Pelvic tilt and truncal inclination: two key radiographic parameters in the setting of adults with spinal deformity

The standing T1-L1 pelvic angle: a useful radiographic predictor of proximal junctional kyphosis in adult spinal deformity

OBJECTIVE

Proximal junctional kyphosis (PJK), which can worsen a patient's quality of life, is a common complication following the surgical treatment of adult spinal deformity (ASD). Although various radiographic parameters have been proposed to predict the occurrence of PJK, the optimal method has not been established. The present study aimed to investigate the usefulness of the T1-L1 pelvic angle in the standing position (standing TLPA) for predicting the occurrence of PJK.

METHODS

The authors retrospectively extracted data for patients with ASD who underwent minimum 5-level fusion to the pelvis with upper instrumented vertebra between T8 and L1. In the present study, PJK was defined as ≥ 10° progression of the proximal junctional angle or reoperation due to progressive kyphosis during 1 year of follow-up. The following parameters were analyzed on whole-spine standing radiographs: the T1-pelvic angle, conventional thoracic kyphosis (TK; T4-12), whole-thoracic TK (T1-12), and the standing TLPA (defined as the angle formed by lines extending from the center of T1 and L1 to the femoral head axis). A logistic regression analysis and a receiver operating characteristic curve analysis were performed.

RESULTS

A total of 50 patients with ASD were enrolled (84% female; mean age 74.4 years). PJK occurred in 19 (38%) patients. Preoperatively, the PJK group showed significantly greater T1-pelvic angle (49.2° vs 34.4°), conventional TK (26.6° vs 17.6°), and standing-TLPA (30.0° vs 14.9°) values in comparison to the non-PJK group. There was no significant difference in the whole-thoracic TK between the two groups. A multivariate analysis showed that the standing TLPA and whole-thoracic TK were independent predictors of PJK. The standing TLPA had better accuracy than whole-thoracic TK (AUC 0.86 vs 0.64, p = 0.03). The optimal cutoff value of the standing TLPA was 23.0° (sensitivity 0.79, specificity 0.74). Using this cutoff value, the standing TLPA was the best predictor of PJK (OR 8.4, 95% CI 1.8-39, p = 0.007).

CONCLUSIONS

The preoperative standing TLPA was more closely associated with the occurrence of PJK than other radiographic parameters. These results suggest that this easily measured parameter is useful for the prediction of PJK.

Assessment of sagittal spinopelvic alignment in asymptomatic Chinese juveniles and adolescents: a large cohort study and comparative meta-analysis

STUDY DESIGN

Retrospective study and comparative meta-analysis.

OBJECTIVE

To document the sagittal spinopelvic alignment in a large cohort study in asymptomatic Chinese juveniles and adolescents, and to explore whether these parameters were different from various regions using meta-analysis.

METHODS

Medical records of 656 asymptomatic Chinese juveniles and adolescents were reviewed, whose mean age was 13.14 ± 3.41 years old, including 254 male and 402 female volunteers. Demographic and lateral radiological parameters were evaluated. Furthermore, a systematic online search was performed to identify eligible studies. Weight mean difference (WMD) with 95% confidence interval (CI) were used to evaluate whether these sagittal parameters were different from various regions.

RESULTS

The mean value of sagittal spinopelvic alignment in this study was calculated and analyzed respectively. Significant differences of PI (34.20 ± 4.00 vs. 43.18 ± 7.12, P < 0.001) and PT (3.99 ± 6.04 vs. 8.42 ± 7.08, P < 0.001) were found between juveniles and adolescents. A total of 17 studies were recruited for meta-analysis. For juvenile populations, TK, PI and SS of Caucasians were significantly larger than those of our study (all P < 0.001). As for adolescent populations, PI (P = 0.017), TK (P = 0.017) and SS (P < 0.001) of Caucasians was found to be greater when compared with that of our study. All in all, TK, PI and SS in Chinese pre-adult populations were significantly smaller than those populations in Caucasian regions (all P < 0.001).

CONCLUSION

Our study was the first large-scale study that reported the mean values of sagittal parameters in asymptomatic Chinese juveniles and adolescents. There were significant differences in TK, PI and SS between our study and other previous reported populations, which reminded us for using specific mean values in different populations when restoring a relatively normal sagittal spinopelvic balance in spinal deformity.

Does Cervical Alignment Matter? The Effect of 2-level Anterior Cervical Discectomy and Fusion on Sagittal Alignment and Patient-reported Outcomes

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

This study aimed to determine the change in cervical sagittal balance following 2-level anterior cervical discectomy and fusion (ACDF) and whether the degree of change was associated with improvement in patient-reported outcomes (PROs).

SUMMARY OF BACKGROUND DATA

Sagittal balance in cervical spine surgery has been recognized as an important surgical goal. However, its influence on clinical outcomes following anterior decompressive procedures remains debatable.

MATERIALS AND METHODS

Patients who underwent primary 2-level ACDF for cervical spondylotic radiculopathy and/or myelopathy were identified from an institutional spine registry. Radiographic measurements were done preoperatively, postoperatively, and at minimum 24 months follow-up. Measurements comprised segmental lordosis (SL), C2-C7 cervical lordosis (CL), C2-C7 sagittal vertical axis, C7 slope (C7S), T1 slope (T1S) and C7 slope minus cervical lordosis (C7S-CL). Disk heights were measured preoperatively and postoperatively. PROs including the Neck Disability Index, Short Form-36, and Visual Analog Scale for neck pain and arm pain were collected preoperatively and at 24 months postoperatively.

RESULTS

In total, 90 patients were included. Mean follow-up was 58.6±22.9 months. Significant improvement in all PROs was achieved at 24 months (P<0.05). SL was -1.2±8.2 degrees preoperatively, increased to 5.2±5.9 degrees postoperatively (P<0.001), and decreased to 1.2±6.2 degrees at follow-up (P=0.005). CL was 8.5±12.5 degrees preoperatively, increased to 10.8±12.4 degrees postoperatively (P=0.018), and maintained at 10.9±11.2 degrees at follow-up (P=0.030). Sagittal vertical axis, C7S, T1S, and C7S-CL did not change significantly. Significant increases in disk heights were achieved postoperatively (P<0.001). Fusion rate was 98.9% at follow-up. PROs were not related to radiologic measurements. Maintaining or increasing CL or SL was not related to a greater degree of improvement in PROs.

CONCLUSIONS

Two-level ACDF restored segmental and global CL, but changes in cervical sagittal alignment did not correlate with the magnitude of improvement in PROs. Adequate decompression with solid fusion remains fundamental to achieving good clinical outcomes in patients with degenerative cervical disease.

Sagittal imbalance of the spine-pelvis-lower extremity axis associated with back-related disability

BACKGROUND

The impact of sagittal imbalance in patients has been reported in LBP and LBP-related disabilities due to spinopelvic imbalance. However, no reports investigating the spine-pelvis-lower extremity axis using lateral images have been reported thus far. This study introduced a novel parameter of the spine-pelvis-lower extremity axis and evaluated whether this parameter was related to symptoms.

METHODS

A total of 343 subjects were included in this cross-sectional study. Standing spine-pelvis and pelvis-lower extremity radiographs were obtained to assess the sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), lumbar lordosis, and thoracic kyphosis. The sacral-knee distance (SKD) (i.e., distance from the anterior femoral condyle to the vertical axis at the upper posterior edge of S1 body) was measured. Furthermore, the SVA/SKD ratio was calculated for global balance. Subjects were divided into leg compensated (LC; SVA/SKD ratio <0.8) and decompensated (LD; SVA/SKD ratio ≥0.8) groups. The SVA was divided into balanced spine (BS; SVA ≤40 mm) and imbalanced spine (IS; SVA >40 mm) groups. All individuals were classified into LC + BS, LC + IS, LD + BS, and LD + IS groups. The relationships among the four groups and low back pain (LBP), Oswestry Disability Index (ODI), and knee pain were examined.

RESULTS

SKD was significantly correlated with SVA, SS, PI, PT, and knee-femoral angle. ODI was significantly higher in the LC + IS group than in the LD + BS group (p < 0.05). Knee pain prevalence was significantly higher in the LC + IS and LC + BS groups than in the LD + IS group (p < 0.05).

CONCLUSION

SVA/SKD ratio is useful for evaluating global alignment. Our findings are significant because they highlight the importance of SKD with respect to knee pain, LBP, and LBP- related disabilities.

Long-term follow-up of untreated Scheuermann's kyphosis

STUDY DESIGN

Long-term cross-sectional study.

OBJECTIVES

To investigate the long-term effects of untreated Scheuermann's kyphosis on quality of life, and its relationship to radiographic parameters of spinal deformity. Previous studies reported reduced self-image, increased pain and impaired physical status. Little is known of the long-term impact of sagittal plane deformity in untreated SK.

METHODS

One hundred and thirteen consecutive untreated patients with SK were identified from a national service database prior to 2000, when surgery was not offered at this unit. 81 of these patients were available for evaluation; 66 (81%) consented to questionnaire and clinical evaluation, and 47 (58%) consented to additional radiological evaluation. Health-related quality of life (HRQoL) was compared to normative population values. Mean age was 45.1 years (31-65), and mean follow-up was 27 years (16-36). 57 patients had thoracic kyphosis and 9 had thoracolumbar deformity.

RESULTS

SRS-22 and SF-36 scores were lower, and ODI was greater in patients with untreated SK compared to normative population values. Kyphosis progressed from mean 66° at skeletal maturity to 78° (p < 0.001) after mean follow-up of 27 years. Long-term progression of untreated SK was 0.45°/year (n = 47). Multilinear regression showed good correlation between increasing SVA and worse ODI scores (r = 0.59; p = 0.001). Increasing SVA also correlated with worse function, pain and mental health scores reported by SRS-22, and with worse physical function and bodily pain scores reported by SF-36. Increasing CL correlated with worse SF-36 physical function scores. Increasing cSVA and increasing TK correlated with worse SRS-22 self-image scores.

CONCLUSION

SRS-22 and SF-36 scores were lower, and ODI was greater in patients with untreated SK compared to normative data. Long-term progression of untreated SK was 0.45°/year (n = 47). Increasing SVA correlated with worse SF-36 physical function, SRS-22 function, SRS-22 pain and higher ODI scores. Total kyphosis (TK) and cSVA were independent predictors of low SRS self-image.

LEVEL OF EVIDENCE

III.

The effect of spinopelvic parameters on transforaminal epidural steroid injection treatment success in lumbar disc herniation

BACKGROUND

Spinopelvic parameters (SPP) is closely associated with diseases such as lumbar disc herniation (LDH), disc degeneration and spondylolisthesis. Although there exist many known clinical and radiological factors affecting the success of the transforaminal epidural steroid injection (TFESI) treatment, the effect of SPP has not yet been investigated. This study aims to examine the effects of SPP on treatment success in patients who undergo TFESI because of lumbar disc herniation and to investigate the correlation among multifidus cross-sectional area (MFCSA).

METHODS

This was a prospective, observational study. Patients with low back and/or leg pain, unilateral nerve root compression were applied TFESI. Outcome measures included the numerical rating scale (NRS), Oswestry Disability Index (ODI) and Beck Depression Inventory (BDI). The patients were evaluated at the first hour, third week and third month. The SPP and MFCSA measurements were made on direct radiographs and MRIs.

RESULTS

A total of 58 patients, 24 women and 34 men, with an average age of 42.0 ± 9.5 were included. NRS, ODI and BDI scores improved significantly up to three months follow-up (P < .001). Moderately positive correlations were found between leg NRS and PT/PI scores immediately after treatment (r: 0.307 and r: 0.334) and a weak positive correlation was found between BDI and PT at third week (r: 0.269). The MFCSA/vertebral sectional area (VSA) and MFCSA/total multifidus cross-sectional area (TMFCSA) of the affected side was found to be significantly low (P < .001).

CONCLUSIONS

Subjects with high PI and PT reported less improvement in leg pain immediately after treatment and patients with high PT had fewer BDI improvements. MFCSA had no correlations with SPPs in patients who underwent TFESI.

Understanding sagittal compensation in adult spinal deformity patients: relationship between pelvic tilt and lower-extremity position

OBJECTIVE

In adult spinal deformity (ASD), quantifying preoperative lower-extremity (LE) compensation is important in formulating an operative plan to achieve optimal global sagittal alignment. Whole-body radiographs are not always available. This study evaluated the possibility of estimating LE compensation without whole-body radiographs.

METHODS

In total, 200 consecutive ASD patients with full-body radiographic assessment were categorized into the following three groups according to their cranio-hip balance (distance from the cranial sagittal vertical axis to the hip axis [CrSVA-H]): group 1, anterior-shift (A-shift) group (CrSVA-H > 40 mm); group 2, balanced group, -40 mm < CrSVA-H < 40 mm; and group 3, posterior-shift (P-shift) group, CrSVA-H < -40 mm. After analyzing the correlation between CrSVA-H, pelvic tilt (PT), and LE parameters, the cutoff PT and PT/pelvic incidence (PI) values that correlated with the presence of LE compensation were determined. Previously published data from asymptomatic volunteers were used as a baseline threshold (sacrofemoral angle [SFA] > 217.0° and knee flexion angle [KA] > 11.0°).

RESULTS

Among the hip, knee, and ankle, only KA showed a significant increase in the A-shift group compared to the other two groups (p < 0.01). With a wide threshold (SFA > 208.0° and KA > 5.0°), 84.9% of the A-shift group showed LE compensation (hip or knee or both), which was a significantly greater percentage than those in the balanced and P-shift groups (48.4% and 51.9%, p < 0.01). With a narrow threshold (SFA > 217.0° and KA > 11.0°), 62.2% of the A-shift group showed any LE compensation, which was also a higher percentage than the other two groups. The CrSVA-H was moderately correlated with KA (r = 0.502), but had no correlation with PT, SFA, and ankle dorsiflexion angle (AA). PT showed a moderate/strong correlation with SFA, KA, and AA (r = 0.846, 0.624, and 0.622, respectively). With receiver operating characteristic curves, the authors determined that a 23.0° PT with PT/PI > 0.46 predicts the presence of any type of LE compensation with use of the wide threshold.

CONCLUSIONS

ASD patients with increased CrSVA-H, which represents cranio-hip anterior imbalance, demonstrated a higher prevalence of LE compensation, especially knee flexion, compared to those with neutral and posterior shift of CrSVA. PT represents the extent of LE compensation in patients with spinal sagittal malalignment. Using the cutoff value of PT determined in this study, surgeons can preoperatively estimate the extent of LE compensation without obtaining a full-body radiograph.

Volume of spinopelvic muscles: comparison between adult spinal deformity patients and asymptomatic subjects

PURPOSE

Spinal muscles are a major component of posture in spinal pathologies and changes to the spine with aging. Specifically, spinopelvic muscles may compensate for underlying anomalies such as pelvic retroversion, knee flexion, and cervical or thoracic spinal balance abnormalities. To increase understanding between muscular characteristics and compensatory mechanisms, this study aimed to compare the volume of spinopelvic muscles in adults with a spinal deformity (ASD) to a control group of well-aligned adult subjects.

METHODS

Twenty-eight lumbar ASD patients [Cobb angle > 20°, > 40 years old (yo)] were prospectively included and compared to 35 normal subjects divided into 2 different groups: one group of young (Y) subjects (n = 23, < 20 yo) and one group of old (O) subjects (n = 12, > 40 yo). All subjects had a fat/water separation MRI (from C7 to the knees). Volumetric 3D reconstructions of 30 spinopelvic muscles were performed and muscles volumes were compared.

RESULTS

Mean age was 60 ± 16 yo, without significant differences between the ASD and O groups (57 ± 11 yo). Age and BMI were smaller in the young group. Mean Cobb angle of the ASD group was 45 ± 11°. Comparing the ASD and O groups, total muscular volume was similar; however, erector spinae (0.24 ± 0.06 vs 0.68 ± 0.08 dm³, p = 0.001), iliopsoas (0.49 ± 0.09 vs 0.60 ± 0.09 dm³, p = 0.001) and obliquus (0.42 ± 0.08 vs 0.50 ± 0.08 dm³, p = 0.02) were significantly smaller in the ASD group. Comparing the Y and the ASD groups, total muscular volume was higher in the Y group than the ASD group (+ 3.3 dm³, p = 0.003) and erector spinae (0.24 ± 0.06 vs 0.74 ± 0.08, p = 0.0001), gluteus medius (0.51 ± 0.07 vs 0.62 ± 0.13, p = 0.01) and vastus lateralis (1.33 ± 0.21 vs 2.08 ± 0.29, p = 0.001) were significantly bigger in the Y group.

CONCLUSION

This is the first study to compare volume of spinopelvic muscles between ASD patients and a control group without spinal deformity. Our results demonstrate that muscular degeneration has a double origin: aging and deformity. Erector spinae, iliopsoas, and obliquus are the muscles most affected by degeneration.

Reliability assessment of cervical spine parameters measured on full-body radiographs in asymptomatic subjects and patients with spinal deformity

BACKGROUND

Cervical spinal alignment is usually assessed on full-body radiographs allowing for the concomitant evaluation of possible compensatory mechanisms that may occur at any level in the setting of postural malalignment.

HYPOTHESIS

Cervical parameters measured on full-body radiographs are reliable.

PATIENTS AND METHODS

A total of 70 subjects were included and divided in 3 groups: asymptomatic adults (n=21), adolescents with idiopathic scoliosis (n=20), and adults with spinal deformity (n=29), for whom full-body low-dose biplanar radiographs were obtained. Eighteen cervical parameters including gaze and cervical curvature, upper cervical spine, global cervical alignment, thoraco-cervical and cervico-pelvic parameters were measured by 4 operators, three times each. The intraclass correlation coefficient (ICC) and the 95% confidence interval (95% CI) where calculated for each parameter and compared between the 3 groups.

RESULTS

ICC and the 95% CI were similar between the 3 groups. The measured parameters showed a very high repeatability (ICC>0.8) except for C0-C2, which presented an average repeatability (ICC=0.57). The cSVA, CTPA, C2-SPi, cranial offset, T1-SPi, CBVA and cranial tilt had a 95% CI<2 (° or cm). The TIA, T1-CL and C0-C2 had a 95% CI>6°.

DISCUSSION

The poor visibility of the foramen magnum, hard palate, C7, T1, and the sternum on radiographs could explain why certain parameters showed a higher measurement error. The assessment of these error margins is essential for an accurate evaluation of cervical spinal deformities and a proper therapeutic approach.

LEVEL OF EVIDENCE

III; retrospective analysis of prospectively collected data.

Does obesity affect acetabular cup position, spinopelvic function and sagittal spinal alignment? A prospective investigation with standing and sitting assessment of primary hip arthroplasty patients

Background

Total hip arthroplasty (THA) instability is influenced by acetabular component positioning, spinopelvic function and sagittal spinal alignment. Obesity is considered as a risk factor of THA instability, but the causal relationship remains unknown. This study aimed to investigate the influence of BMI on (1) spinopelvic function (lumbar flexibility, pelvic mobility and hip motion), (2) sagittal spinal alignment pre- and postoperatively and (3) acetabular cup position postoperatively in primary THA patients in a prospective setting.

Methods

One hundred ninety patients receiving primary total hip arthroplasty were enrolled in a prospective cohort study and retrospectively analysed. All patients received stereoradiography (EOS) in standing and relaxed sitting position pre-and postoperatively. C7-sagittal vertical axis (C7-SVA), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), anterior plane pelvic tilt (APPT), and pelvic femoral angle (PFA) were assessed. Key parameters of the spinopelvic function were defined as lumbar flexibility (∆ LL = LL_standing − LL_sitting), pelvic mobility (∆ PT = PT_standing − PT_sitting) and hip motion (∆ PFA = PFA_standing − PFA_sitting). Pelvic mobility was further defined based on ∆ PT as stiff, normal and hypermobile (∆ PT < 10°; 10°–30°; > 30°). The patients were stratified to BMI according to WHO definition: normal BMI ≥ 18.5–24.9 kg/m² (n = 68), overweight ≥ 25.0–29.9 kg/m² (n = 81) and obese ≥ 30–39.9 kg/m² (n = 41). Post-hoc analysis according to Hochberg's GT2 was applied to determine differences between BMI groups.

Results

Standing cup inclination was significant higher in the obese group compared to the normal BMI group (45.3° vs. 40.1°; p = 0.015) whereas standing cup anteversion was significantly decreased (22.0° vs. 25.3°; p = 0.011). There were no significant differences for spinopelvic function key parameter lumbar flexibility (∆ LL), pelvic mobility (∆ PT) and hip motion (∆ PFA) in relation to BMI stratified groups. The obese group demonstrated significant enhanced pelvic retroversion compared to the normal BMI group (APPT − 1.8° vs. 2.4°; p = 0.028). The preoperative proportion of stiff pelvic mobility was decreased in the obese group (12.2%) compared to normal (25.0%) and overweight (27.2%) groups. Spinal sagittal alignment in C7-SVA and PI-LL mismatch demonstrated significantly greater imbalance in the obese group compared to the normal BMI group (68.6 mm vs. 42.6 mm, p = 0.002 and 7.7° vs. 1.2°, p = 0.032, respectively) The proportion of patients with imbalanced C7-SVA was higher in the obese (58.5%) than in the normal BMI group (44.1%).

Conclusions

The significantly increased spinal sagittal imbalance with altered pelvic mechanics is a potential cause for the reported increased risk of THA dislocations in obese patients. Consequently, the increased spinal sagittal imbalance in combination with normal pelvic mobility need to be taken into account when performing THA in obese patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02716-8.

Determining the validity and reliability of spinopelvic parameters through comparing standing whole spinal radiographs and upright computed tomography images

Background

Standing whole spinal radiographs are used to evaluate spinal alignment in adult spinal deformity (ASD), yet some studies have reported that pelvic incidence, pelvic tilt, and thoracic kyphosis (TK) intra- and inter-observer reliability is low. This study aimed to evaluate the accuracy of spinopelvic parameters through comparing standing whole spinal radiographs and upright CT images.

Methods

We enrolled 26 patients with ASD. All standing whole spinal posterior/anterior and lateral radiographs and upright whole spinal CT had been obtained in a natural standing position. Two examiners independently measured 13 radiographic parameters. Interclass correlation coefficients (ICCs) were used to analyze measurement intra- and inter-observer reliability. Paired t- and Pearson’s correlation tests were used to analyze validity of the standing whole spinal radiographs.

Results

ICCs of upright CT were excellent in both intra- and inter-observer reliability. However, intra-observer ICCs for TK2–12, TK1–5, TK2–5, and TK5–12 on standing lateral radiographs were relatively low, as were inter-observer ICCs for TK2–12, TK1–5, TK2–5, and TK5–12. Concerning TK values, the difference between the radiographs and CT in TK1–12 and TK2–12 were 4.4 ± 3.1 and 6.6 ± 4.6, respectively, and TK values from T2 showed greater measurement error (p < 0.05).

Conclusions

Upright CT showed excellent intra- and inter-observer reliability in the measurement of spinopelvic parameters. Measurement of TK with T2 on standing whole spinal radiographs resulted in a greater measurement error of up to 6.6°. Surgeons need to consider this when planning surgery and measuring postoperative TK changes in patients with ASD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04786-5.

Prevalence and location of endplate fracture and subsidence after oblique lumbar interbody fusion for adult spinal deformity

BACKGROUND

Recently, Oblique lumbar interbody fusion (OLIF) is commonly indicated to correct the sagittal and coronal alignment in adult spinal deformity (ASD). Endplate fracture during surgery is a major complication of OLIF, but the detailed location of fracture in vertebral endplate in ASD has not yet been determined. We sought to determine the incidence and location of endplate fracture and subsidence of the OLIF cage in ASD surgery, and its association with fusion status and alignment.

METHODS

We analyzed 75 levels in 27 patients were analyzed using multiplanar CT to detect the endplate fracture immediately after surgery and subsidence at 1 year postoperatively. The prevalence was compared between anterior and posterior, approach and non-approach sides, and concave and convex side. Their association with fusion status, local and global alignment, and complication was also investigated.

RESULTS

Endplate fracture was observed in 64 levels (85.3%) in all 27 patients, and the incidence was significantly higher in the posterior area compared with the anterior area (85.3 vs. 68.0%, p=0.02) of affected vertebra in the sagittal plane. In the coronal plane, there was no significant difference in incidence between left (approach) and right (non-approach) sides (77.3 and 81.3%, respectively), or concave and convex sides (69.4 and 79.6%) of wedged vertebra. By contrast, cage subsidence at 1 year postoperatively was noted in 14/75 levels (18.7%), but was not associated with endplate fracture. Fusion status, local and global alignment, and complications were not associated with endplate fracture or subsidence.

CONCLUSION

Endplate fracture during OLIF procedure in ASD cases is barely avoidable, possibly induced by the corrective maneuver with ideal rod counter and cantilever force, but is less associated with subsequent cage subsidence, fusion status, and sustainment of corrected alignment in long fusion surgery performed even for elderly patients.

Lower pelvic tilt, lower pelvic incidence, and increased external rotation of the iliac wing in patients with femoroacetabular impingement due to acetabular retroversion compared to hip dysplasia

AIMS

The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?

METHODS

A retrospective, review board-approved, controlled study was performed including 120 hips in 86 consecutive patients with symptomatic FAI or hip dysplasia. Pelvic CT scans were reviewed to calculate parameters for sagittal balance (pelvic incidence (PI), PT, and sacral slope), anterior pelvic plane angle, pelvic inclination, and external rotation of the iliac wing and were compared to a control group (48 hips). The 120 hips were allocated to the following groups: AR (41 hips), hip dysplasia (47 hips) and cam FAI with normal acetabular morphology (32 hips). Subgroups of total AR (15 hips) and high acetabular anteversion (20 hips) were analyzed. Statistical analysis was performed using analysis of variance with Bonferroni correction.

RESULTS

PI and PT were significantly decreased comparing AR (PI 42° (SD 10°), PT 4° (SD 5°)) with dysplastic hips (PI 55° (SD 12°), PT 10° (SD 6°)) and with the control group (PI 51° (SD 9°) and PT 13° (SD 7°)) (p < 0.001). External rotation of the iliac wing was significantly increased comparing AR (29° (SD 4°)) with dysplastic hips (20°(SD 5°)) and with the control group (25° (SD 5°)) (p < 0.001). Correlation between external rotation of the iliac wing and acetabular version was significant and strong (r = 0.81; p < 0.001). Correlation between PT and acetabular version was significant and moderate (r = 0.58; p < 0.001).

CONCLUSION

These findings could contribute to a better understanding of hip pain in a sitting position and extra-articular subspine FAI of patients with AR. These patients have increased iliac external rotation, a rotational abnormality of the iliac wing. This has implications for surgical therapy with hip arthroscopy and acetabular rim trimming or anteverting periacetabular osteotomy (PAO). Cite this article: Bone Jt Open 2021;2(10):813-824.

Lordosis Distribution Index in Short-Segment Lumbar Spine Fusion - Can Ideal Lordosis Reduce Revision Surgery and Iatrogenic Deformity?

OBJECTIVE

The demand for spinal fusion is increasing, with concurrent reports of iatrogenic adult spinal deformity (flatback deformity) possibly due to inappropriate lordosis distribution. This distribution is assessed using the lordosis distribution index (LDI) which describes the upper and lower arc lordosis ratio. Maldistributed LDI has been associated to adjacent segment disease following interbody fusion, although correlation to later-stage deformity is yet to be assessed. We therefore aimed to investigate if hypolordotic lordosis maldistribution was associated to radiographic deformity-surrogates or revision surgery following instrumented lumbar fusion.

METHODS

All patients undergoing fusion surgery ( ≤ 4 vertebra) for degenerative lumbar diseases were retrospectively included at a single center. Patients were categorized according to their postoperative LDI as: "normal" (LDI 50-80), "hypolordotic" (LDI < 50), or "hyperlordotic" (LDI > 80).

RESULTS

We included 149 patients who were followed for 21 ± 14 months. Most attained a normally distributed lordosis (62%). The hypolordotic group had increased postoperative pelvic tilt (PT) (p < 0.001), pelvic incidence minus lumbar lordosis (PI-LL) mismatch (p < 0.001) and decreased global lordosis (p = 0.007) compared to the normal group. Survival analyses revealed a significant difference in revision surgery (p = 0.03), and subsequent multivariable logistic regression showed increased odds of 1-year revision in the hypolordotic group (p = 0.04). There was also a negative, linear correlation between preoperative pelvic incidence (PI) and postoperative LDI (p < 0.001).

CONCLUSION

In patients undergoing instrumented lumbar fusion surgery, hypolordotic lordosis maldistribution (LDI < 50) was associated to increased risk of revision surgery, increased postoperative PT and PI-LL mismatch. Lordosis distribution should be considered prior to spinal fusion, especially in high PI patients.

Obeid-Coronal Malalignment Classification Is Age Related and Independently Associated to Personal Reported Outcome Measurement Scores in the Nonfused Spine

Objective

To evaluate Obeid-coronal malalignment (O-CM) modifiers according to age, sagittal alignment, and patient-reported outcome measures (PROMs), in the mobile spine.

Methods

Retrospective review of a prospective multicenter adult spinal deformity (ASD) database with 1,243 (402 nonoperative, 841 operative) patients with no prior fusion surgery. Patients were included if they were aged over 18 years and were affected by spinal deformity defined by one of: Cobb angle ≥ 20°, pelvic tilt ≥ 25°, sagittal vertical axis ≥ 5 cm, thoracic kyphosis ≥ 60°. Patients were classified according to the O-CM classification and compared to coronally aligned patients. Multivariate analysis was performed on the relationship between PROMs and age, global tilt (GT) and coronal malalignment (CM).

Results

Four hundred forty-three patients had CM of more than 2 cm compared to 800 who did not. The distribution of these modifiers was correlated to age. After multivariate analysis, using age and GT as confounding factors, we found that before the age of 50 years, 2A1 patients had worse sex life and greater satisfaction than patients without CM. After 50 years of age, patients with CM (1A1, 1A2) had worse self-image and those with 2A2, 2B had worse self-image, satisfaction, and 36-item Short Form Health Survey physical function. Self-image was the consistent determinant of patients opting for surgery for all ages.

Conclusion

CM distribution according to O-CM modifiers is age dependent. A clear correlation between the coronal malalignment and PROMs exists when using the O-CM classification and in the mobile spine, this typically affects self-image and satisfaction. Thus, CM classified according to O-CM modifiers is correlated to PROMs and should be considered in ASD.

The Hip-Spine Challenge

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The proper diagnosis and treatment of patients with concurrent hip and spine pathological processes can be challenging because of the substantial overlap in symptomatology.

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There is no consensus on which pathological condition should be addressed first.

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Factors such as advanced spinal degeneration, deformity, and prior fusion alter the biomechanics of the spinopelvic unit. Attention should be paid to recognizing these issues during the work-up for a total hip arthroplasty as they can result in an increased risk of dislocation.

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In patients with concurrent spine and hip degeneration, the surgeon must pay close attention to appropriate implant positioning and have consideration for implants with enhanced stability to minimize the risk of dislocation.

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A proper understanding of sagittal balance and restoration of this balance is integral to improving patient outcomes following spinal surgery.

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The advent of new imaging modalities, increased awareness of spinopelvic mobility, as well as a better understanding of sagittal alignment will hopefully improve our treatment of patients with hip-spine syndrome.

Effects of different pedicle screw insertion depths on sagittal balance of lumbar degenerative spondylolisthesis, a retrospective comparative study

BACKGROUND

Few reports to date have evaluated the effects of different pedicle screw insertion depths on sagittal balance and prognosis after posterior lumbar interbody and fusion (PLIF) in patients with lumbar degenerative spondylolisthesis (LDS).

METHODS

A total of 88 patients with single-level PLIF for LDS from January 2018 to December 2019 were enrolled. Long screw group (Group L): 52 patients underwent long pedicle screw fixation (the leading edge of the screw exceeded 80% of the anteroposterior diameter of vertebral body). Short screw group (Group S): 36 patients underwent short pedicle screw fixation (the leading edge of the screw was less than 60% of the anteroposterior diameter of vertebral body). Local deformity parameters of spondylolisthesis including slip degree (SD) and segment lordosis (SL), spino-pelvic sagittal plane parameters including pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and lumbar lordosis (LL), Oswestry Disability Index (ODI), and Visual Analog Scale (VAS) for back pain of both groups were compared. Postoperative complications, including vertebral fusion rate and screw loosening rate, were recorded.

RESULTS

Except that PI in Group S at the final follow-up was not statistically different from the preoperative value (P > 0.05), other parameters were significantly improved compared with preoperative values one month after surgery and at the final follow-up (P < 0.05). There was no significant difference in parameters between Group L and Group S before and one month after surgery (P > 0.05). At the final follow-up, SD, SL, LL, PT and PI-LL differed significantly between the two groups (P < 0.05). Compared with the preoperative results, ODI and VAS in both groups decreased significantly one month after surgery and at the final follow-up (P < 0.05). Significant differences of ODI and VAS were found between the two groups at the final follow-up (P < 0.05). Postoperative complications were not statistically significant between the two groups (P > 0.05).

CONCLUSIONS

PLIF can significantly improve the prognosis of patients with LDS. In terms of outcomes with an average follow-up time of 2 years, the deeper the screw depth is within the safe range, the better the spino-pelvic sagittal balance may be restored and the better the quality of life may be.

Thoracic Reciprocal Change Can Be Predicted Before Surgery in Adult Spinal Deformity

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Analysis of postoperative sagittal alignment of the unfused spine is lacking in patients with adult spinal deformity (ASD). The present study aims to evaluate the efficacy of the whole spine full-flexion lateral radiograph to predict the reciprocal change of the unfused spine after correction surgery. We hypothesized that the novel parameter (T1-UIV angle: angle between the upper vertebral endplate of the T1 and the upper vertebral endplate of the upper instrumented vertebra) of the preoperative whole spine full-flexion lateral radiograph is similar to that of the postoperative lateral radiograph if the patient has the ideal sagittal alignment.

METHODS

Twenty-six ASD patients who underwent correction surgery with a minimum 2-year follow-up were enrolled and separated into the Ideal and Non-Ideal groups according to the Scoliosis Research Society (SRS)-Schwab classification of the final follow-up radiograph. Radiographic parameters, including T1-UIV of the preoperative whole spine full-flexion lateral radiograph, were obtained.

RESULTS

Thirteen patients were included in the Ideal group and 13 were in Non-Ideal group. Preoperative T1-UIV of the whole spine full-flexion lateral radiograph exhibited significant correlations with the T1-UIV angles of the postoperative and final follow-up radiographs (r = 0.64, P < .01, y = 0.800x + 8.012, and r = 0.69, P < .01, y = 0.857x + 2.960, respectively). Interestingly, this correlation was stronger for the Ideal group (r = 0.77, P < .01, y = 1.207x - 1.517, and r = 0.89, P < .01, y = 0.986x + 0.694, respectively).

CONCLUSION

A novel radiographic strategy (T1-UIV of preoperative the whole spine full-flexion lateral radiograph) could estimate the postoperative alignment of the unfused spine correctly.

Spine-Pelvis-Hip Alignments in Degenerative Spinal Deformity Patients and Associated Procedure of One-Stage Long-Fusion with Multiple-Level PLIF or Apical-Vertebra Three Column Osteotomy-a Clinical and Radiographic Analysis Study

OBJECTIVE

To explore the spine-pelvis-hip alignments in degenerative spinal deformity (DSD) patients, and compare the outcomes in the procedure of long-fusion with posterior lumbar inter-body fusion (PLIF) or single-level three-column osteotomy (STO) at lower lumbar level (LLL, L3 -S1 ) and thoracolumbar levels (TLL, T10 -L2 ) for those patients.

METHODS

This is a retrospective study. Following institutional ethics approval, a total of 83 patients (Female, 67; Male, 16) with DSD underwent long-fusion with PLIF or STO surgery between March 2015 and December 2017 were reviewed. All of those patients were assigned into LLL and TLL groups. The average age at surgery was 65.2 years (SD, 8.1). Demographic (age, gender, BMI, and comorbidities), radiographs (both coronal and sagittal parameters) and health-related quality of life (HRQOL) assessments were documented. The radiographic parameters and HRQOL-related measurements at pre- and post-operation were compared with paired-samples t test, and those variables in the two groups were analyzed using an independent-sample t test. The relationships between pelvic incidence (PI) and other sagittal parameters were investigated with Pearson correlation analysis. The Pearson χ2 or Fisher's exact was carried out for comparison of gender, incidence of comorbidities and post-operative complications.

RESULTS

There were 53 and 30 patients in the LLL and TLL groups respectively. Those spino-pelvic radiographic parameters had significant improvements after surgeries (P < 0.001). The patients in the two group with different pre-operative thoracolumbar kyphosis (TLK, P = 0.003), PI (P = 0.02), and mismatch of PI minus lumbar lordosis (PI-LL, P = 0.01) had comparable post-operative radiographic parameters except PI (P = 0.04) and pelvic-femur angle (PFA, P = 0.02). Comparing the changes of those spine-pelvic-hip data during surgeries, the corrections of TLK in TLL group were significant larger (P = 0.004). Pearson correlation analysis showed that there were negative relationship between PI and TLK (r = -0.302, P = 0.005), positive relationship between PI and LL (r = 0.261, P = 0.016) at pre-operation. Those patients underwent the surgical procedure that long-segment instrumentation and fusion with STO would have higher incidence of complications involving longer operative timing (P = 0.018), more blood loss (P < 0.001), revision surgery (P = 0.008), and cerebrospinal fluid leakage (P = 0.001). All the HRQOL scores significantly improved at final follow-up (P < 0.001), with no difference of intra-group.

CONCLUSION

Patients suffered de-novo scoliosis or hyper-kyphosis with low PI would be vulnerable to significant thoracolumbar degeneration, and have more changes of spine-pelvis-hip data after long-fusion surgery, however, those with high PI would be closed to significant lumbar degeneration. Although spine-pelvis-hip alignments in DSD patients can be restored effectively after long-fusion with PLIF or STO, the incidence of complications in patients underwent STO was significant higher than that in patients performed multi-level PLIF.

Association of Sagittal Spinopelvic Realignment with Correction in Lower Lumbar Lordosis after Surgical Treatment in Degenerative Lumbar Scoliosis

Objective

To assess the effect that correction of lower lumbar lordosis (3L) has on global spine realignment due to the key role of 3L for scoliosis surgery in patients with degenerative lumbar scoliosis (DLS).

Methods

This study is a retrospective review performed between June 2018 and January 2020, including consecutive patients with DLS. Only patients age ≥ 45 years who had already undergone a selective root block operation and had the procedure of long‐fusion extending to pelvis and posterior lumbar interbody fusion (PLIF) at lower lumbar spine (L₄‐S₁) were retained for analysis. Spinopelvic parameters measured included thoracic kyphosis (TK), lumbar lordosis (LL), 3L, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), T₁ pelvic angle (TPA), and sagittal vertical axis (SVA) at pre‐operation and the third month follow‐up. The mismatch (PI‐LL) was calculated subsequently. Pearson correlation and linear regression analysis were performed to explore the association of the changes in global spinopelvic parameters with 3L correction.

Results

Thirty‐nine patients (five males, 34 females) with the average age of 63.84 years (SD 7.53; range, 45–75 years) at the time of surgery were identified. All patients had the surgical procedure of long‐fusion (≥4 vertebras) with PLIF at lower lumbar spine between L₄ and S₁ spine. Lower instrumented vertebras (LIV) fused to pelvis (S₁, 14; S₂, 18; ilium, 7) were operated in all patients. Seventeen patients were with upper instrumented vertebras (UIV) at thoracolumbar spine (L₂‐T₁₁), and 22 patients at thoracic spine (T10 and above). The median of instrumented segments was 10 (5–14). 3L significantly increased (P = 0.02) after surgical treatment by mean change of 4.21° (range, −19.7° to +22.2°). Perioperatively, all spinopelvic parameters regarding to TK, LL, SS, PT, TPA, SVA, and mismatch (PI‐LL) had significant changes (P < 0.001). The change in 3L correlated significantly with the changes in spinopelvic parameters (r = 0.772 for LL, −0.589 for SVA, −0.439 for TPA, and −0.428 for PI‐LL). After linear regression analysis, the formulas were obtained: d‐LL = 14.977 + 0.636 × d‐3L, (R² = 0.596); d‐(PI‐LL) = 16.575 + 0.62 × d‐3L, (R² = 0.183); d‐TPA = −7.284 to 0.358 × d‐3L, (R² = 0.193); d‐SVA = −30.556–2.639 × d‐3L (R² = 0.347).

Conclusions

Correction in lower lumbar lordosis, following the surgical procedure of long‐fusion with PLIF at lower lumbar spine, could result in significant changes in full‐spine parameters. The significant association of changes in each of global spine parameter with the correction of 3L perioperatively could provide important information for surgeons to make a surgical plan for spinal correction.

Global alignment taking into account the cervical spine with odontoid hip axis angle (OD-HA)

INTRODUCTION

Global alignment analysis is of upmost importance in adult spinal deformity patients (ASD). Numerous parameters exist in the literature to measure global alignment based upon C7 or T1. One common limitation of these parameters is that they neglect the cervical segment which is essential in spinal compensatory mechanisms and in horizontal gaze preservation. A recent stereoradiography analysis of asymptomatic subjects introduced a new 3D parameter (ODHA), defined as the angle between the vertical reference line and the line joining the odontoid tip (OD) to hip axis center (HA). Thus, the goal of this study was to analyze 3D global alignment of ASD patients using the new parameter odontoid hip axis angle and its relationship to other spinal parameters.

METHODS

In this prospective study, 90 adult patients with lumbar scoliosis (Cobb > 20°) were included. All subjects underwent low dose biplanar X-rays with 3D spinal reconstructions. Based on published normative values of ODHA, we defined abnormally high value as mean ODHA of asymptomatic subject + 2SD (i.e., ODHA > 6.1°). Values of 3D radiographic parameters and ODI were compared between patients with ODHA > 6.1° and < 6.1°.

RESULTS

Mean ODHA was 5+/- 3.6° (0.4° to 18.6°). 22 patients had abnormally high ODHA. They were older than the 68 other patients (68+/- 9y vs 53+/- 14y, p = 0.001), without any significant difference in terms of sex, BMI and rate of rotatory subluxation (54% vs 62%, p = 0.06). However, coronal and sagittal deformity was more important in patients with abnormal ODHA (larger Cobb angle, coronal malalignment, pelvic tilt and lower lumbar lordosis). Patients with abnormal ODHA had significantly worst ODI (50+/- 23 vs 30+/- 18, p = 0.0005).

CONCLUSION

Extreme values of ODHA are observed in significantly older patients with significant functional impairment. In addition, in these patients with sagittal malalignment with loss of lumbar lordosis, who recruit compensatory mechanisms such as pelvic retroversion, the cervical area is also involved with a posture in cervical hyperlordosis to maintain the head over the pelvis. Thus, ODHA is an interesting parameter allowing a more comprehensive alignment measurement taking into account the mechanisms of compensation of the cervical spine to the pelvis.

Dose-response relationship between spino-pelvic alignment determined by sagittal modifiers and back pain-specific quality of life

PURPOSE

To determine whether abnormalities of the sagittal modifiers (SMs) of the Scoliosis Research Society (SRS)-Schwab classification truly reflect back pain (BP)-specific quality of life (QOL), it is necessary to examine their dose-response relationships and to determine clinically impactful thresholds for declines in BP-specific QOL. This study aimed to analyse the continuous dose-response relationship between each SM and BP-specific QOL.

METHODS

This cross-sectional study, using data from a Japanese population-based cohort study, included 519 community-dwelling residents aged ≥ 50 years who participated in the annual health examination. The participants completed the Roland-Morris Disability Questionnaire (RDQ) on BP-specific QOL. Spino-pelvic alignment based on SMs was assessed by whole-spine X-ray examinations. We fitted general linear models with or without nonlinear terms to estimate the dose-response relationship between each SM and BP-specific QOL.

RESULTS

Pelvic tilt, pelvic incidence minus lumbar lordosis (PI-LL), and sagittal vertical axis showed dose-response relationships with BP-specific QOL measured as the RDQ score. PI-LL was most likely to predict a minimally clinically important RDQ score when its value exceeded the 90th percentile. A nonlinear relationship between PI-LL and the BP-specific QOL score was found. RDQ increased when PI-LL exceeded 10°.

CONCLUSION

PI-LL might be the most sensitive of the three modifiers of the SRS-Schwab classification for determining BP-specific QOL. Moreover, BP-specific QOL worsens rapidly when the compensatory mechanism against malalignment exceeds a critical value. Therefore, we suggest that traditional classifications and surgical strategies should be re-examined regarding the dose-dependent abnormalities of the SMs to develop a more reliable classification strategy.

Efficacy and radiographic analysis of oblique lumbar interbody fusion in treating adult spinal deformity

Adult spinal deformity (ASD) is usually rigid and requires a combined anterior–posterior approach for deformity correction. Anterior lumbar interbody fusion (ALIF) allows direct access to the disc space and placement of a large interbody graft. A larger interbody graft facilitates correction of ASD. However, an anterior approach carries significant risks. Lateral lumbar interbody fusion (LLIF) through a minimally invasive approach has recently been used for ASD. The present study was performed to evaluate the effectiveness of oblique lumbar interbody fusion (OLIF) in the treatment of ASD. We performed a retrospective study utilizing the data of 74 patients with ASD. The inclusion criteria were lumbar coronal Cobb angle > 20°, pelvic incidence (PI)–lumbar lordosis (LL) mismatch > 10°, and minimum follow–up of 2 years. Patients were divided into two groups: ALIF combined with posterior spinal fixation (ALIF+PSF) (n = 38) and OLIF combined with posterior spinal fixation (OLIF+PSF) (n = 36). The perioperative spinal deformity radiographic parameters, complications, and health-related quality of life (HRQoL) outcomes were assessed and compared between the two groups. The preoperative sagittal vertical axis (SVA), LL, PI–LL mismatch, and lumbar Cobb angles were similar between the two groups. Patients in the OLIF+PSF group had a slightly higher mean number of interbody fusion levels than those in the ALIF+PSF group. At the final follow–up, all radiographic parameters and HRQoL scores were similar between the two groups. However, the rates of perioperative complications were higher in the ALIF+PSF than OLIF+PSF group. The ALIF+PSF and OLIF+PSF groups showed similar radiographic and HRQoL outcomes. These observations suggest that OLIF is a safe and reliable surgical treatment option for ASD.

The impact of preoperative supine radiographs on surgical strategy in adult spinal deformity

OBJECTIVE

Preoperative planning for adult spinal deformity (ASD) surgery is essential to prepare the surgical team and consistently obtain postoperative alignment goals. Positional imaging may allow the surgeon to evaluate spinal flexibility and anticipate the need for more invasive techniques. The purpose of this study was to determine whether spine flexibility, defined by the change in alignment between supine and standing imaging, is associated with the need for an osteotomy in ASD surgery.

METHODS

A single-center, dual-surgeon retrospective analysis was performed of adult patients with ASD who underwent correction of a thoracolumbar deformity between 2014 and 2018 (pelvis to upper instrumented vertebra between L1 and T9). Patients were stratified into osteotomy (Ost) and no-osteotomy (NOst) cohorts according to whether an osteotomy was performed (Schwab grade 2 or higher). Demographic, surgical, and radiographic parameters were compared. The sagittal correction from intraoperative prone positioning alone (sagittal flexibility percentage [Sflex%]) was assessed by comparing the change in lumbar lordosis (LL) between preoperative supine to standing radiographs and preoperative to postoperative alignment.

RESULTS

Demographics and preoperative and postoperative sagittal alignment were similar between the Ost (n = 60, 65.9%) and NOst (n = 31, 34.1%) cohorts (p > 0.05). Of all Ost patients, 71.7% had a grade 2 osteotomy (mean 3 per patient), 21.7% had a grade 3 osteotomy, and 12.5% underwent both grade 3 and grade 2 osteotomies. Postoperatively, the NOst and Ost cohorts had similar pelvic incidence minus lumbar lordosis (PI-LL) mismatch (mean PI-LL 5.2° vs 1.2°; p = 0.205). Correction obtained through positioning (Sflex%) was significantly lower for in the osteotomy cohort (38.0% vs 76.3%, p = 0.004). A threshold of Sflex% < 70% predicted the need for osteotomy at a sensitivity of 78%, specificity of 56%, and positive predictive value of 77%.

CONCLUSIONS

The flexibility of the spine is quantitatively related to the use of an osteotomy. Prospective studies are needed to determine thresholds that may be used to standardize surgical decision-making in ASD surgery.

Sagittal Plane Alignment and Functional Outcomes Following Surgery for Scheuermann Kyphosis

Objective  To evaluate and correlate the pelvic parameters, the sagittal balance (SB), and the functional outcome of the patients submitted to surgical treatment for Scheuermann hyperkyphosis (SK).

Methods  Patients submitted to surgery between January 2005 and December 2016 were included. The following radiographic measurements were obtained: thoracic kyphosis (TK); lumbar lordosis (LL); SB; pelvic incidence (PI); pelvic tilt (PT); and sacral slope (SS). Complications during the follow-up period were recorded.

Results  A total of 19 patients were included (16 males): the mean preoperative kyphosis was of 83°, and the postoperative kyphosis was of 57°. The mean preoperative lumbar lordosis was of 66°, with a postoperative spontaneous correction of 47°. Regarding the preoperative pelvic parameters, the average PI, PT and SS were of 48°,10° and 39° respectively. In the postoperative period, these values were of 50°, 16° and 35° respectively. The preoperative SB was neutral, and it was maintained after the surgical correction. Concerning complications during the follow-up period, three junctional kyphosis were observed–two requiring revision surgery, one nonunion, and one dehiscence of the surgical wound. Regarding the functional results, the average score on the Scoliosis Research Society-22 (SRS-22) patient questionnaire was of 4.04, and we verified that the SB obtained in the postoperative period had no influence on the functional outcome ( p  = 0.125) nor on the postoperative LL ( p  = 0.851).

Conclusion  We verified a spontaneous improvement in the lumbar hyperlordosis at levels not included in the fusion after correction of the TK. Although the postoperative functional results were globally high, we did not find any statistically significant relationship with TK nor LLs. high PI is associated with a greater rate of complications regarding the proximal junctional kyphosis (PJK), and these pelvic parameters should be considered at the time of the SK surgical treatment.

Improvements in lower-extremity patient-reported outcomes after lumbar interbody fusion

OBJECTIVE

Recently, new patient-reported outcome measures (PROMs) of the spine were designed to overcome the limitations of previous spinal PROMs and to consider the whole spine as a single kinetic functional unit. Owing to the significance of spine-hip-knee and global body balance, the spine and lower extremities cannot be considered separately. However, no reports have evaluated lower-extremity functional outcome using PROMs after lumbar spine surgery. The authors aimed to elucidate changes in hip and knee PROMs after lumbar interbody fusion and to evaluate the sagittal spinopelvic radiographic parameters that were most strongly correlated with lower-extremity PROMs.

METHODS

In 2018, the authors consecutively evaluated patients who underwent lumbar interbody fusion surgery with at most three levels. Preoperative and 1-year postoperative clinical and radiographic data were assessed. Spinal functional outcomes were measured with the Oswestry Disability Index (ODI), visual analog scale (VAS) for pain, and Scoliosis Research Society-22r (SRS-22r) questionnaire. Lower-extremity functional outcomes were evaluated with the Harris Hip Score (HHS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Linear regression was used to evaluate the relationship between spinal and lower-extremity PROMs and spinopelvic radiographic parameters.

RESULTS

The authors enrolled 67 patients, with a mean age of 66.4 years. The average number of surgical levels was 1.7. All assessed PROMs improved significantly after surgery (p < 0.001 for ODI, p < 0.001 for VAS, p = 0.017 for SRS-22r, p = 0.042 for HHS, and p = 0.033 for WOMAC). Spinopelvic parameters, including lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and sagittal radiographic parameters of hip and knee, significantly improved after surgery. On linear regression analysis, HHS and WOMAC correlated with LL and PT, respectively (β = 0.554 and p = 0.043 for correlation of HHS with LL; β = 1.573 and p = 0.021 for correlation of WOMAC with PT).

CONCLUSIONS

The current study demonstrated that lumbar fusion surgery may induce postoperative improvements in lower-extremity functional and radiological outcomes. However, among radiographic parameters, changes in LL and PT were the most strongly associated with lower-extremity PROMs.

The Comparison of Spinopelvic Parameters, Complications, and Clinical Outcomes After Spinal Fusion to S1 with or without Additional Sacropelvic Fixation for Adult Spinal Deformity: A Systematic Review and Meta-analysis

STUDY DESIGN

Systematic review and meta-analysis.

OBJECTIVE

The purpose of the study was to compare the outcomes and after spinal fusion with or without iliac screw (IS) insertion for patients with adult spinal deformity (ASD).

SUMMARY OF BACKGROUND DATA

The number of patients undergoing multilevel spinal stabilization for the treatment of ASD is growing. However, the selection of spinopelvic fixation for ASD patients with long fusion is controversial.

METHODS

A comprehensive literature search was performed without time restriction according to the guidelines from the Cochrane Collaboration in May 2020 using PubMed, EMBASE, and the Cochrane Library. The comparison of the two types of fixation was evaluated by spinopelvic parameters, incidence rate of complications, rate of revision, and clinical outcomes at the last follow-up.

RESULTS

The literature search identified 422 records, of which eight studies were included for meta-analysis with a total of 439 patients. All the included studies provided level III evidence. There was no significant difference in the sagittal vertical axis, pelvic incidence, the proximal junctional kyphosis rates, the pseudarthrosis rates, the revision rates, and the clinical outcomes at the last follow-up between those who receive sacrum fixation and sacropelvic fixation. Nevertheless, greater lumbar lordosis (LL) (weighted mean difference [WMD], 4.15; 95% confidence interval [CI] 2.46-5.84, P < 0.01), greater sacral slope (SS) (WMD, 2.32; 95% CI 1.21-3.43, P < 0.01), and lower rate of the distal instrumentation instability (odds ratio, 0.25; 95% CI 0.10-0.61, P = 0.002) were observed in IS group between the comparison.

CONCLUSION

The clinical outcomes in the IS group were similar to those in the non-IS group, but the application of the IS significantly restored LL, prevented decompensation, and reduced the occurrence of the distal instrumentation instability. Therefore, the IS may be a good choice for the operative treatment of ASD patients with sagittal malalignment and other risks of lumbosacral fracture, metal breakage, and screw pullout.Level of Evidence: 3.

Pedicle subtraction osteotomy with patient-specific instruments

Background

Although the utility of patient-specific instruments (PSI) has been well established for complex osteotomies in orthopedic surgery, it is yet to be comparatively analyzed for complex spinal deformity correction, such as pedicle subtraction osteotomy (PSO).

Methods

Six thoracolumbar human cadavers were used to perform nine PSOs using the free-hand (FH) technique and nine with PSI (in total 18 PSOs). Osteotomy planes were planned on the basis of preoperative computed tomography (CT). A closing-wedge angle of 30° was targeted for each PSO. Postoperative CT scans were obtained to measure segmental lordosis correction and the deviation from the planned 30° correction as well as the osseous gap of posterior elements.

Results

The time required to perform a PSO was 18:22 (range 10:22–26:38) min and 14:14 (range 10:13–22:16) min in the PSI and FH groups, respectively (p = 0.489). The PSI group had a significantly higher lordosis gain (29°, range 23–31° vs. 21°, range 13–34°; p = 0.015). The lordosis gain was significantly more accurate with PSI (deviation angle: 1°; range 0–7°) than with the FH technique (9°; range 4–17°; p = 0.003). PSI achieved a significantly smaller residual osseous gap of the posterior elements (5 mm; range 0–9 mm) than the FH group (11 mm; range 3–27 mm; p = 0.043).

With PSI, an angular difference of 3° (range 1–12°), a translational offset of 1 (range 0–6) mm at the level of the lamina, and a vertebral body entry point deviation of 1 (range 0–4) mm was achieved in the osteotomies.

Conclusions

PSI-guided PSO can be a more feasible and accurate approach in achieving a planned lordosis angle than the traditional FH technique in a cadaver model. This approach further reduced osseous gaps, potentially promoting higher fusion rates in vivo.

Incidence of Chronic Periscapular Pain After Adult Thoracolumbar Deformity Correction and Impact on Outcomes

OBJECTIVE

Extension of the posterior upper-most instrumented vertebra (UIV) into the upper thoracic (UT) spine allows for greater deformity correction and reduced incidence of proximal junction kyphosis (PJK) in adult spinal deformity (ASD) patients. However, it may be associated with chronic postoperative scapular pain (POSP). The goal of this study was to assess the relationship between UT UIV and persistent POSP, describe the pain, and assess its impact on patient disability.

METHODS

ASD patients who underwent multilevel posterior fusion were retrospectively identified then administered a survey regarding scapular pain and the Oswestry Disability Index (ODI), by telephone. Univariate and multivariate analysis were utilized.

RESULTS

A total of 74 ASD patients were included in the study: 37 patients with chronic POSP and 37 without scapular pain. The mean age was 70.5 years, and 63.9% were women. There were no significant differences in clinical characteristics, including mechanical complications (PJK, pseudarthrosis, and rod fracture) or reoperation between groups. Patients with persistent POSP were more likely to have a UT than a lower thoracic UIV (p = 0.018). UT UIV was independently associated with chronic POSP on multivariate analysis (p = 0.022). ODI score was significantly higher in patients with scapular pain (p = 0.001). Chronic POSP (p = 0.001) and prior spine surgery (p = 0.037) were independently associated with ODI on multivariate analysis.

CONCLUSION

A UT UIV is independently associated with increased odds of chronic POSP, and this pain is associated with significant increases in patient disability. It is a significant clinical problem despite solid radiographic fusion and the absence of PJK.

Relative pelvic version displays persistent compensatory measures with normalised sagittal vertical axis after deformity correction

PURPOSE

A normal sagittal vertical axis (SVA) after spinal deformity correction can yield mechanical complications of up to 30%. Post-operative compensatory pelvic orientation can produce a normal SVA. We assess relative pelvic version (RPV), an individualised measure, for persistent post-operative compensatory measures.

METHODS

Adult spinal deformity (ASD) patients who were treated operatively, with a normal SVA (< ± 50 mm) at 6-week follow-up were included, who were then followed-up after 2 years. These only included patients with fusion of > 4 vertebrae extending to L5 or below. Six-week subgroups were made regarding pelvis orientation, relative pelvic version (RPV: anteversion, aligned, moderate or severe retroversion) with analysis of patient-related outcome measures (PROMs), complications and spino-pelvic sagittal parameters.

RESULTS

At 6 weeks, 140 patients met the inclusion criteria, 5 (3.6%) patients had anteversion, 59 (42.1%) were aligned, 60 (42.9%) had moderate retroversion and 16 (11.4%) patients had severe retroversion. Follow-up after 2 years demonstrated increased RPV in all groups except the severe RPV group who were more likely to develop SVA > 50 mm. Complications occurred in all groups. Significant 2-year differences were observed between moderate and severe RPV for back pain and PROMs but not between other RPV groups.

CONCLUSION

Adult spinal deformity patients with a normal SVA after spino-pelvic instrumentation carry a significant risk of retroversion progression post-operatively, followed by increased positive sagittal balance. Relative pelvic version (RPV) measurements when categorised into anteversion, aligned, moderate retroversion and severe retroversion at 6 weeks were predictive of PROMs at 2 years.

Surgical strategy for revisional lumbar pedicle subtraction osteotomy to correct fixed sagittal imbalance: The effect of the osteotomy level and iliac screw fixation

BACKGROUND

More caudal osteotomy is believed to lead to greater sagittal correction; however, the osteotomy level and whether or not to use iliac screw fixation (ISF) are topics of on-going debate. The aim of this study was to compare clinical and radiographic outcomes after revisional lumbar pedicle subtraction osteotomy (PSO) for fixed sagittal imbalance (FSI) according to the osteotomy level and ISF.

METHODS

All consecutive patients who underwent revisional PSO (at L3 or L4) for FSI in a single institute from July 2006 to January 2014 were investigated retrospectively. Thirty-eight patients with at least 2-year follow-up were finally included. Clinical outcomes including the visual analogue scale (VAS) and Oswestry Disability Index (ODI) were investigated. Radiographic spinopelvic parameters were analyzed according to the level of PSO, the degree of correction, and the use of ISF.

RESULTS

The mean number of fused segments after PSO was 6.6 ± 1.8. Sagittal vertical axis (SVA) was restored after the surgery (12, 2.5, and 5.2 cm at preoperative, postoperative, and the last follow-up, respectively). PSO was performed at L3 in 16 patients and at L4 in 22 patients. The osteotomy level was not associated with any changes of spinopelvic parameters (pelvic tilt [PT] or lumbar lordosis) or sagittal alignment (T1-pelvic angle [TPA] or SVA). However, better TPA restoration was achieved with more osteotomy resection angle (P = 0.031). ISF group showed significant improvement in postoperative pelvic orientation (PT and ratio of PT to pelvic incidence) which was maintained until the last follow-up.

CONCLUSIONS

Although postoperative sagittal alignment was different in FSI patients according to the osteotomy level, pelvic orientation improved in ISF group. Also, the degree of correction showed significant associations with sagittal alignment. When performing revisional PSO for FSI, spine surgeon should carefully consider how to correct rather than where to do the osteotomy, and the role of ISF.

Progression of pelvic retroversion is a critical factor for clinical outcome after Opening-wedge high tibial osteotomy among elderly patients

Purpose

To evaluate the clinical outcome after opening-wedge high tibial osteotomy (OWHTO) and to determine the critical factors for a poor clinical outcome after OWHTO in patients aged over 65 years.

Methods

Our retrospective analysis was based on the data from 233 patients who underwent OWHTO for medial compartment knee OA at our institution between January 2013 and December 2018, and 88 patients (36 men and 52 women) over 65 years of age were included in this study. Radiographic parameters of weight-bearing line ratio (WBLR) and pelvic inclination (PI); the knee function, range of motion (ROM) and extension; and clinical outcome with Lysholm score were obtained preoperatively and postoperatively at the final follow-up visit. To evaluate the critical factors for the clinical outcome, univariate regression analysis was used to identify the relationship between postoperative and improved Lysholm score and pre-and post-operative essential factors. To reveal the factor having a greater impact on the clinical outcome, a p < 0.05 in univariate factors was entered into a multivariate regression analysis.

Results

The preoperative WBLR was significantly changed, and Lysholm score improved from 59.5 to 81.5 (p < 0.0001), whereas the PI, knee extension and ROM were not changed after OWHTO. Regarding the essential factors affecting clinical outcome after OWHTO, age and delta PI were negative, whereas preoperative WBLR, postoperative ROM, especially extension, had a positive effect (p < 0.05). Furthermore, only delta PI had affected the improvement of clinical outcome with OWHTO (p < 0.01), and postoperative knee extension was negatively correlated with the progression of pelvic retroversion (p < 0.01).

Conclusion

Age at surgery and progression of pelvic retroversion were the critical factors for poor postoperative clinical outcomes after OWHTO. Care should be taken for the progression of pelvic retroversion after OWHTO because it deteriorates the clinical outcome by inducing the knee flexion contracture as the compensatory mechanism for the balance of sagittal alignment.

Pelvic incidence change on the operating table

PURPOSE

While a change in the pelvic incidence (PI) after long spine fusion surgery has been reported, no studies have examined the change in the PI on the operating table. The present study examined the PI-change on the operating table and elucidated the patients' background characteristics associated with this phenomenon.

METHODS

This study included patients who underwent lumbar posterior spine surgery and had radiographs taken in a full-standing position preoperatively and a pelvic lateral radiograph in the prone position in the operative room. The patients with PI-change on the operating table (PICOT; PICOT group) and without PICOT (control group) were compared for their background characteristics and preoperative radiographic parameters.

RESULTS

There were 128 eligible patients (62 males, 66 females) with a mean age (± standard deviation) of 69.9 ± 11.7 (range: 25-93) years old. Sixteen patients (12.5%) showed a decrease in the PI > 10°, which indicated placement in the PICOT group. The preoperative lumbar lordosis (LL) and PI-LL in the PICOT group were significantly worse than those in the control group (LL: 20.8 ± 16.6 vs. 30.6 ± 16.2, p = 0.0251, PI-LL: 33.9 ± 19.0 vs. 17.3 ± 14.8, p < 0.0001). The PICOT group had a higher proportion of patients who underwent fusion surgery than the control group, but the difference was not significant (62.5% vs. 44.6%, p = 0.1799).

CONCLUSION

A decreased PI was observed in some patients who underwent lumbar posterior surgery on the operating table before surgery. Patients with a PI decrease on the operating table had a significantly worse preoperative global alignment than those without such a decrease.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Does Achieving Global Spinal Alignment Lead to Higher Patient Satisfaction and Lower Disability in Adult Spinal Deformity?

STUDY DESIGN

Multicenter retrospective review of prospective database.

OBJECTIVE

The aim of this study was to investigate potential associations between postoperative alignment and satisfaction.

SUMMARY OF BACKGROUND DATA

Achieving high satisfaction is the main goal of any treatment, including adult spinal deformity (ASD) surgery. Despite being one of the key elements, literature is sparse regarding postoperative factors influencing patient satisfaction.

METHODS

ASD patients with 2-year follow-up were retrospectively reviewed. Patients without revision after the index procedure were stratified according to deformity type: sagittal (T1 pelvic angle >22°), coronal (C7 plumb line [C7PL] >5 cm or MaxCobb >50°), or mixed. Bivariate correlation between satisfaction and postoperative data was conducted on the entire cohort as well as by type of preoperative deformity. Multivariate regression controlling for pre-op alignment and demographic information was used to identify independent predictors of 2Y satisfaction.

RESULTS

A total of 509 patients were included in the analysis (58.7 ± 14.8, 80% females). The quality of life significantly improved between pre- and 2-year (ΔOswestry Disability Index [ODI]: 17.6, p < 0.001). At 2 years, SRS22 satisfaction was 4.27 ± 0.89 (median 4.5). Significant associations were found between satisfaction and disability (ODI, r = -0.50) and global coronal (C7PL r = -0.15) and sagittal (sagittal vertical axis [SVA], r = -0.10) alignment (all p < 0.01) but not with the coronal clavicle angle. Stratification by preoperative deformity revealed significant associations between satisfaction and SVA for sagittal deformity only, C7PL and MaxCobb for coronal only, and C7PL for combined deformity. In the multivariate analysis controlling for demographic and pre-op deformity, 2-year ODI and 2-year C7PL were independent predictors of satisfaction. Multilinear regression demonstrated 2-year SVA, pre-op ODI and patient's age were the independent predictors 2-year ODI.

CONCLUSION

The ability to restore global alignment depends on the severity of the preoperative deformity as well as the correction of the main aspect of the deformity. Achieving global coronal and sagittal alignment is an independent predictor of both satisfaction and disability at 2 years post-op. Patients who continue to be disabled are also not satisfied.Level of Evidence: 3.

Surgical Restoration of Sagittal Alignment of the Spine: Correlation with Improved Patient-Reported Outcomes: A Systematic Review and Meta-Analysis

BACKGROUND

The sagittal-plane curvatures of the human spine are the consequence of evolution from quadrupedalism to bipedalism and are needed to maintain the center of mass of the body within the base of support in the bipedal position. Lumbar degenerative disorders can lead to a decrease in lumbar lordosis and thereby affect overall alignment of the spine. However, there is not yet enough direct evidence that surgical restoration of spinal malalignment would lead to a better clinical outcome. Therefore, the aim of this study was to assess the correlation between patient-reported outcomes and actual obtained spinal sagittal alignment in adult patients with lumbar degenerative disorders who underwent surgical treatment.

METHODS

A comprehensive literature search was conducted through databases (PubMed, Cochrane, Web of Science, and Embase). The last search was in November 2018. Risk of bias was assessed with the Newcastle-Ottawa quality assessment scale. A meta-regression analysis was performed.

RESULTS

Of 2,024 unique articles in the original search, 34 articles with 973 patients were included. All studies were either retrospective or prospective cohort studies; no randomized controlled trials were available. A total of 54 relations between preoperative-to-postoperative improvement in patient-reported outcome measures (PROMs) and radiographic spinopelvic parameters were found, of which 20 were eligible for meta-regression analysis. Of these, 2 correlations were significant: pelvic tilt (PT) versus Oswestry Disability Index (ODI) (p = 0.009) and PT versus visual analog scale (VAS) pain (p = 0.008).

CONCLUSIONS

On the basis of the current literature, lower PT was significantly correlated with improved ODI and VAS pain in patients with sagittal malalignment caused by lumbar degenerative disorders that were treated with surgical correction of the sagittal balance.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Sagittal imbalance influences outcome of vertebroplasty in patients with osteoporotic vertebral compression fracture

BACKGROUND AND OBJECTIVES

The correlation between sagittal balance of the spine and clinical outcome after vertebroplasty (VP) in patients with osteoporotic vertebral compression fractures (OVCF) is poorly investigated. We analysed the clinical outcome of patients with OVCF undergoing VP taking into account sagittal balance.

MATERIAL AND METHOD

The primary endpoint was the change in axial back pain, disability and health-related quality-of-life using Visual Analogue Scale (VAS), Oswestry Disability Index (ODI) and SF-36, respectively, in correlation to the parameters that define sagittal balance (SVA). Radiographic assessment included full spine standing lateral films. Imaging and clinical data were collected pre- and post-procedure at 1, 3 and 12 months.

RESULTS

51 patients were included presenting a total of 113 OVCF. 30 patients (60.7%) had multiple OVCF. Comparing the evolution of VAS and ODI throughout the follow-up it does not seem that there are significant differences in their behaviour between the SVA>50mm and the SVA<50mm groups (p>0.05). On the contrary, pre-VP SF-36 scores showed worst results in the SVA>50mm group in the physical functioning (PF) section (p<0.05) and in the physical component score (PCS) (p<0.05). These differences were maintained until 3 months of follow-up in the case of the PCS and until the end of follow-up in the case of the PF (p<0.05).

CONCLUSIONS

Patients with a SVA>50mm showed a slower recovery of their quality-of-life after VP for OVCF, but without significant differences with respect to pain or disability, when compared patients with SVA<50mm.

Demographic, Surgical, and Radiographic Risk Factors for Symptomatic Adjacent Segment Disease After Lumbar Fusion: A Systematic Review and Meta-Analysis

BACKGROUND

Although multiple studies have investigated risk factors for symptomatic adjacent segment disease (ASD) after lumbar fusion, their findings were diverse and inconsistent. This review aimed to summarize risk factors for ASD in order to guide the management of ASD and future research.

METHODS

Six electronic databases were systematically searched from inception to December 2019. Two reviewers independently screened titles, abstracts, and full-text articles to identify studies investigating risk factors for ASD after lumbar fusion in humans. The methodological quality of the included studies and the strength of evidence regarding risk factors were evaluated.

RESULTS

Sixteen studies involving 3,553 patients were included. Meta-analyses revealed that high body mass index, facet joint violation, anterior shift of the preoperative and postoperative lumbosacral sagittal plumb line, decreased preoperative and postoperative lumbar lordosis, preoperative adjacent disc degeneration, decreased preoperative adjacent disc height, increased postoperative lumbopelvic mismatch, postoperative pelvic incidence, and postoperative pelvic tilt were significantly related to ASD.

CONCLUSIONS

This meta-analysis addressed the limitations of prior reviews and summarized evidence with regard to risk factors for ASD following lumbar fusion. Future prospective studies should investigate whether modification of these risk factors can reduce the ASD development.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

The impact of sagittal imbalance on walking in patients with lumbar spinal canal stenosis

PURPOSE

Gait and posture disorder severely impedes the quality of life of affected patients with lumbar spinal canal stenosis (LSCS). Despite the major health concern, there is a paucity of literature about the relationships among spatiotemporal gait parameters and spinal sagittal parameters. This is a cross sectional study performed in a single tertiary referral center to determine the relationships among spatiotemporal gait parameters and spinal sagittal parameters in patients with LSCS.

METHODS

A total of 164 consecutive patients with LSCS, 87 men and 77 women with mean age of 70.7 years, were enrolled. Spatiotemporal gait parameters were studied using a gait analysis system. Spinal sagittal parameters were studied including sagittal vertical axis (SVA), thoracic kyphosis (TK), lumbar lordosis (LL), sacral slope (SS), pelvic inclination (PI), and pelvic tilt (PT) both in the neutral and stepped positions.

RESULTS

SVA was significantly larger in the stepped position than in the neutral position (neutral position, 72.5 mm; stepped position, 96.8 mm; p = 0.003). Parameters regarding the pelvis exhibited significant differences, which could represent pelvic anteversion in the stepped position. By stepwise multiple regression analysis, the prediction models, containing SVA (neutral) and PT (stepped) for double supporting phase, exhibited statistical significance, and accounted for approximately 50% of the variance.

CONCLUSIONS

The present study provides statistically established evidence of correlation among spatiotemporal gait parameters and spinal sagittal parameters. Differences between sagittal parameters in neutral and stepped position may stand for the postural control during gait cycle, and increased SVA in neutral position and increased PT in stepped position may correlate with prolonged double supporting phase.

Does spinal sagittal imbalance lead to future vertebral compression fractures in osteoporosis patients?

BACKGROUND CONTEXT

Many risk factors for osteoporotic vertebral compression fractures (OVCFs) have been reported. However, there are few reports on the relationship between spine sagittal parameters in patients with osteoporosis.

PURPOSE

To explore whether: spinal sagittal imbalance is associated with future vertebral compression fractures in osteoporosis patients; spinal sagittal parameters in patients with osteoporosis can predict the occurrence of vertebral compression fractures.

STUDY DESIGN

A retrospective cohort study.

PATIENT SAMPLE

Patients with osteoporosis.

OUTCOME MEASURES

Occurrence of OVCFs during the follow-up period.

METHODS

From January 2017 to October 2019, eligible patients with osteoporosis at the initial visit were enrolled. They were followed up to November 1, 2020. Based on whether OVCFs occurred during the follow-up, the patients were divided into two groups: the experimental group (vertebral compression fracture group) and the control group (no vertebral compression fracture group). Intragroup analysis was performed as follows: Pearson and Spearman correlation coefficients were used to calculate the correlation between each parameter. Intergroup analysis was performed as follows. For categorical variables, the chi-square test was used; for normally distributed continuous variables, an independent sample t-test was used; and for non-normally distributed variables, a two-sample nonparametric test was used. Binary logistic regression analysis and receiver operating characteristic (ROC) curves were used to determine independent risk factors and critical values, respectively.

RESULTS

A total of 340 patients with osteoporosis were enrolled. The longest and shortest follow-up periods were 44 months and 12 months, respectively, with an average of 25.2±10.2 months. There were significant differences in age, bone mineral density (femur and lumbar), smoking history, medication treatment regularity, Thoracolumbar Kyphosis (TLK), Pelvic Tilt (PT), C7-S1 Sagittal Vertical Axis (C7-S1 SVA), and C2-7 Sagittal Vertical Axis (C2-7 SVA) between the experimental and control groups. There were no significant differences in sex, body mass index (BMI), alcohol consumption history, hypertension, diabetes, coronary heart disease, family history of osteoporosis, physical activity, Thoracic Kyphosis (TK), Lumbar Lordosis (LL), Pelvic Incidence (PI), Sacral Slope (SS), C2-C7 Cobb Angle (CL), T1 slope (T1S) or blood parameters. Through binary logistic regression analysis, we found that BMD, medication treatment regularity and C7-S1 SVA were independent risk factors for future vertebral compression fractures. According to the ROC curve, the prediction accuracy of C7-S1 SVA was the highest. Through the calculation of critical values, we found that when C7-S1 SVA was more than 3.81 cm, future OVCFs were more likely to occur, and for every 1cm increase in C7-S1 SVA, the incidence of future OVCFs would increase by 0.324 times (p<.001, OR=1.324). Through intragroup analysis, we further found that C7-S1 SVA was positively correlated with the percentage of vertebral body wedging.

CONCLUSIONS

For patients with osteoporosis, a C7-S1 SVA more than 3.81cm is significantly associated with a greater risk for vertebral compression fractures in the future.

Survival analysis and risk factors of new vertebral fracture after vertebroplasty for osteoporotic vertebral compression fracture

BACKGROUND CONTEXT

Although risk factors of new adjacent vertebral fracture (AVF) and remote vertebral fracture (RVF) after vertebroplasty may differ, research on this topic is lacking.

PURPOSE

To determine the natural course of new vertebral fractures after vertebroplasty for osteoporotic vertebral compression fracture (OVCF) and to analyze each risk factor for understanding the incidence of AVF and RVF.

STUDY DESIGN

Retrospective cohort study.

PATIENT SAMPLE

The study subjects included 205 patients who received vertebroplasty for OVCF and were followed-up for at least 1-year.

OUTCOME MEASURES

Data on factors that could affect the occurrence of vertebral fractures, such as age, body mass index, and bone density, were collected from the patients' medical records. Fracture pattern, fracture location, sagittal imbalance, degree of segmental kyphosis after vertebroplasty, cement distribution, and cement leakage were radiologically examined.

METHODS

xDuring the follow-up period, any newly developed vertebral fractures were identified. We analyzed whether the time of occurrence differed between AVF and RVF by performing a survival analysis and each risk factor separately.

RESULTS

New vertebral fractures occurred in 47 patients (22.9%) after vertebroplasty, AVF occurred in 21 patients (10.2%), and RVF occurred in 26 patients (12.7%). The onset time of AVF was 6.2±1.8 months after vertebroplasty, showing a significant difference from that of RVF, which was 15.2±1.8 months (p<.001). In the univariate analysis, the risk factors of AVF included severe osteoporosis (T-score<-3.0), vertebroplasty in the thoracolumbar junction, sagittal imbalance, and segmental kyphosis angle >15° (p=0.029, p=0.033, p=0.001, and p=0.021, respectively). The risk factors of RVF included severe osteoporosis (T-score <-3.0) and sagittal imbalance (p=0.013 and p=0.004). In the multivariate analysis, the risk factors of AVF included vertebroplasty in the thoracolumbar junction and sagittal imbalance (hazard ratio=3.34, p=0.032 and hazard ratio=4.05, p=0.008), and those of RVF included only sagittal imbalance (hazard ratio=2.66, p=0.024).

CONCLUSON

After vertebroplasty for OVCF, a significant difference in the meantime of occurrence was found; it took 6 months for AVF and 15 months for RVF to develop. Vertebroplasty in the thoracolumbar junction was identified as a risk factor for AVF, whereas sagittal imbalance was a risk factor of both AVF and RVF.

Predictors of Falls in Patients with Degenerative Cervical Myelopathy: A Prospective Multi-institutional Study

STUDY DESIGN

Prospective multicenter study.

OBJECTIVES

The purpose of this study was to characterize a population of patients with degenerative cervical myelopathy (DCM) combined with a history of falling, and to identify the predictors associated with those falls.

SUMMARY OF BACKGROUND DATA

Falls among patients with DCM are common and can lead to the worsening of neurological symptoms. However, there are no prospective studies that have investigated the risk factors for falls in these patients.

METHODS

We prospectively enrolled patients scheduled for surgery for DCM and evaluated the significance of various preoperative measures for predicting falls. We then examined the correlation between the number of falls and the preoperative factors. Lastly, we performed stepwise logistic regression analysis to assess the concurrent effects of various factors on the occurrence of falls.

RESULTS

Among the 135 patients analyzed, 64 experienced one or more falls from the time of enrollment to 1 year postoperatively. Univariate analysis showed that the preoperative potassium and albumin levels, handgrip strength, and the Japanese Orthopaedic Association score for the assessment of cervical myelopathy (C-JOA score) were lower and Nurick grade was higher in the fallers group. Serum potassium level, handgrip strength, C-JOA score, Nurick grade, European Quality of Life-5 Dimensions (EQ-5D) score, t1 pelvic angle, and sagittal vertical axis had weak correlations with the number of falls. The fallers group had a lower C-JOA and EQ-5D scores and a lower recovery rate at one year postoperatively. Stepwise multiple logistic regression analysis identified preoperative potassium level and handgrip strength as the independent preoperative predictors for falling.

CONCLUSION

We identified preoperative lower serum potassium level and weaker handgrip strength as significant predictors of falls in patients with DCM. Therefore, DCM patients with these risk factors should be cautious about falls and might be candidates for immediate surgical intervention.Level of Evidence: 3.

Fulcrum to Generate Maximum Extension of the Spine and Hip-Proposing A New Strategy using EOS Imaging for Patient-specific Assessment of Degenerated Lumbar Spines

STUDY DESIGN

A retrospective, radiographic comparative study conducted in a single academic institution.

OBJECTIVE

This study aims to compare fulcrum extension with conventional extension imaging to determine maximum "hip lordosis" (HL), an important novel patient-specific parameter in spinal realignment surgery, as well as understand the extension capabilities of the lower lumbar spine, which together, are key contributors to whole-body balancing.

SUMMARY OF BACKGROUND DATA

Recent literature recognizes the hip as an important contributor to whole-body lordosis beyond a compensator for spinal imbalance.

METHODS

Patients >45 years' old with mechanical low back pain due to degenerative spinal conditions were included and grouped based on the imaging performed-fulcrum or conventional extension. All imaging was performed using EOS under standardized instructions and visual aids. Radiographic parameters include global lumbar angle (GLA), inflexion-S1 (Inf-S1) angle, segmental lumbar angles, pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), femoral alignment angle (FAA), HL and spinocoxa angle (SCA). Unpaired t test was used to compare between radiographic parameters.

RESULTS

One hundred patients (40 males and 60 females, mean age 63.0 years) underwent either fulcrum or conventional extension EOS® imaging. Both groups had comparable baseline radiographic parameters. Fulcrum extension gave a larger mean GLA (-60.7° vs. -48.5°, P = 0.001), Inf-S1 angle (-58.8° vs. -48.8°, P = 0.003), SCA (-36.5° vs. -24.8°, P < 0.001), L4/5 and L5/S1 lordosis (-20.7° vs. -17.7°, P = 0.041, and -22.3° vs. -17.1°, P = 0.018, respectively), compared to conventional extension. PI, SS, PT, FAA, and HL were similar between both extension postures.

CONCLUSION

Fulcrum extension, compared to conventional extension, is better at generating lordosis in the lower lumbar spine, thus improving preoperative assessment of stiffness or instability of the lumbar spine. Both extension methods were equally effective at determining the patient-specific maximum HL to assess the flexibility and compensation occurring at the hip, potentially guiding surgical management of patients with degenerative spines.Level of Evidence: 3.

The effect of minimally invasive lumbar decompression surgery on sagittal spinopelvic alignment in patients with lumbar spinal stenosis: a 5-year follow-up study

OBJECTIVE

Several studies have examined the relationship between sagittal spinopelvic alignment and clinical outcomes after spinal surgery. However, the long-term reciprocal changes in sagittal spinopelvic alignment in patients with lumbar spinal stenosis after decompression surgery remain unclear. The aim of this study was to investigate radiographic changes in sagittal spinopelvic alignment and clinical outcomes at the 2-year and 5-year follow-ups after minimally invasive lumbar decompression surgery.

METHODS

The authors retrospectively studied the medical records of 110 patients who underwent bilateral decompression via a unilateral approach for lumbar spinal stenosis. Japanese Orthopaedic Association (JOA) and visual analog scale (VAS) scores for low-back pain (LBP), leg pain, leg numbness, and spinopelvic parameters were evaluated before surgery and at the 2-year and 5-year follow-ups. Sagittal malalignment was defined as a sagittal vertical axis (SVA) ≥ 50 mm.

RESULTS

Compared with baseline, lumbar lordosis significantly increased after decompression surgery at the 2-year (30.2° vs 38.5°, respectively; p < 0.001) and 5-year (30.2° vs 35.7°, respectively; p < 0.001) follow-ups. SVA significantly decreased at the 2-year follow-up compared with baseline (36.1 mm vs 51.5 mm, respectively; p < 0.001). However, there was no difference in SVA at the 5-year follow-up compared with baseline (50.6 mm vs 51.5 mm, respectively; p = 0.812). At the 5-year follow-up, 82.5% of patients with preoperative normal alignment maintained normal alignment, whereas 42.6% of patients with preoperative malalignment developed normal alignment. Preoperative sagittal malalignment was associated with the VAS score for LBP at baseline and 2-year and 5-year follow-ups and the JOA score at the 5-year follow-up. Postoperative sagittal malalignment was associated with the VAS score for LBP at the 2-year and 5-year follow-ups and the VAS score for leg pain at the 5-year follow-up. There was a trend toward deterioration in clinical outcomes in patients with persistent postural malalignment compared with other patients.

CONCLUSIONS

After minimally invasive surgery, spinal sagittal malalignment can convert to normal alignment at both short-term and long-term follow-ups. Sagittal malalignment has a negative impact on the VAS score for LBP and a weakly negative impact on the JOA score after decompression surgery.

Analysis of Radiographic Spinopelvic Parameters in Patients With Degenerative Lumbar Kyphoscoliosis

Purpose:

To analyze the relationships between coronal and sagittal spinopelvic parameters in degenerative lumbar kyphoscoliosis (DLKS).

Methods:

We enrolled 75 patients with DLKS for a radiographic study between January 2016 and September 2018. Correlations between coronal and sagittal spinopelvic radiographic parameters were analyzed. Then patients were divided into 2 groups: sagittal balanced group (SVA< = 5 cm, 30 patients) and sagittal imbalanced group (SVA >5 cm, 45 patients), and relevant parameters were compared.

Results:

The Cobb angle and lumbar lordosis of the DLKS patients were 24.87 ± 11.59° and 17.26 ± 12.24°, respectively. The average age was 68 years old (range: 42-82), and the sex ratio was 2.6:1 (female: 54 patients; male: 21 patients). 50 patients (66.7%) located convexity of the curve at left side, while 25 patients (33.3%) at right side. The Cobb angle correlated with LL-TK (r = −0.228, p = 0.049), LL (r = −0.255, p = 0.027) and SS (r = −0.232, p = 0.045). There were significant differences in PI-LL (t = −3.484, P = 0.001), LL-TK (t = 2.354, P = 0.023), PI (t = −3201, P = 0.002) and PT (t = −2.521, P = 0.014) between sagittal balanced and imbalanced group.

Conclusions:

In degenerative lumbar kyphoscoliosis, there are some correlations between coronal and sagittal spinopelvic parameters. Moreover, PI-LL, LL-TK, PI, PT were significantly different between sagittal balanced and imbalanced DLKS patients.

Analysis of individual differences in pelvic and spine alignment in seated posture and impact on the seatbelt kinematics using human body model

Analysis using human body models has been performed to reduce the impact of accidents; however, no analysis has shown a relationship between lumbar and pelvic/spine angle and seat belts in reducing human damage from accidents. Lumbar and pelvic/spine angles were measured in 75 individuals and the measurements were used to create three different angles for the Total Human Model for Safety model. In the present study, we focused on lumber lordosis (LL) and pelvic angle (PA). A normal distribution and histogram were used for analysis of PA (01, 10, and 50). The Total Human Model for Safety, including LL and PA, was corrected using finite element software. Simulations were conducted under the conditions of the Japan New Car Assessment Programme (JNCAP) 56 kph full lap frontal impact. Using the results of the FEM, the amount of lap-belt cranial sliding-up, anterior movement of the pelvis, posterior tilt of the pelvis, head injury criterion (HIC), second cervical vertebrae (C2) compressive load, C2 moment, chest deflectiou (upper, middle, and lower), left and right femur load, and shoulder belt force were measured. The lap-belt cranial sliding-up was 1.91 and 2.37 for PA10 and PA01, respectively, compared to PA50; the anterior movement of the pelvis was 1.08 and 1.12 for PA10 and PA01, respectively; and the posterior tilt of the pelvis was 1.1 and 1.18 for PA10 and PA01, respectively. HIC was 1.13 for PA10 and 1.58 for PA01; there was no difference in C2 compressive load by PA, but C2 moment increased to 1.59 for PA10 and 2.72 for PA01. It was found that as LL increases and the PA decreases, the seat belt becomes likely to catch the iliac bone, making it harder to cause injury. This study could help to reconsider the safe seat and seatbelt position in the future.

The aging spine: the effect of vertebral fragility fracture on sagittal alignment

Our study investigates the relationship, in the aging population, between vertebral fractures, spinal alignment, and quality of life. Kyphotic fractures were related to more significant disability and impaired spinopelvic alignment. The spinal malalignment was strongly associated with fractures in the thoracolumbar junction vertebrae and the absence of powerful compensatory mechanisms as thoracic hypokyphosis and lower lumbar hyperlordosis.

INTRODUCTION

In adult spine deformity (ASD), the sagittal imbalance is defined by the deformity in the sagittal plane that causes the need for greater use of muscle strength to maintain an upright static posture or walking. Fragility vertebral fractures (VF) and ASD are frequent causes of spinal morbidity in the elderly. The prevalence of both ASD and VF increases with aging. Although these two clinical conditions insist on the same population, little is known about the interactions between sagittal imbalance and vertebral fracture (VF) deformity. The aim of our work is to examine the associations between vertebral fractures, sagittal alignment, and their impact on the quality of life scores in elderly patients.

METHODS

A retrospective cohort study of 110 patients of both sexes, from a spine surgery waiting list, with at least one VF with ≥ 5° of kyphosis and a full-standing X-ray.

INDEPENDENT VARIABLES

the presence of VF with kyphotic deformity ≥ 10°, fracture level, degree of kyphosis (deformity) of the fracture, number of fractures, spinopelvic angular parameters, demographic parameters, and scales of evaluation of the health-related quality of life.

RESULTS

A total of 110 patients with mean age 73.8 ± 5.2, of which 70 women (63%) were included in the study. Subjects with at least one VF ≥ 10° presented greater disability and an overall worse sagittal spinal alignment (no VF10° vs VF10°: TPA 21.30 ± 11.5 vs 26.51 ± 12.6, p = 0.041) and more disability (no VF10° vs VF10°: ODI 41.91 ± 16.9 vs 54.67 ± 15.8, p < 0.001) than patients with less degree of vertebral deformity. Significant compensatory mechanisms involved the thoracic area and the lower lumbar region.

CONCLUSION

Kyphotic VFs were associated with severe alterations of sagittal spine alignment and perceived disability. Subjects with sagittal imbalance have a greater degree of deformity in the thoracolumbar junction area. Thoracic hypokyphosis and lower lumbar hyperlordosis are effective compensatory mechanisms in case of lumbar or thoracic fracture, respectively.

Clinical photographs in the assessment of adult spinal deformity: a comparison to radiographic parameters

OBJECTIVE

The goal of this study was to reliably predict sagittal and coronal spinal alignment with clinical photographs by using markers placed at easily localized anatomical landmarks.

METHODS

A consecutive series of patients with adult spinal deformity were enrolled from a single center. Full-length standing radiographs were obtained at the baseline visit. Clinical photographs were taken with reflective markers placed overlying C2, S1, the greater trochanter, and each posterior-superior iliac spine. Sagittal radiographic parameters were C2 pelvic angle (CPA), T1 pelvic angle (TPA), and pelvic tilt. Coronal radiographic parameters were pelvic obliquity and T1 coronal tilt. Linear regressions were performed to evaluate the relationship between radiographic parameters and their photographic "equivalents." The data were reanalyzed after stratifying the cohort into low-body mass index (BMI) (< 30) and high-BMI (≥ 30) groups. Interobserver and intraobserver reliability was assessed for clinical measures via intraclass correlation coefficients (ICCs).

RESULTS

A total of 38 patients were enrolled (mean age 61 years, mean BMI 27.4 kg/m2, 63% female). All regression models were significant, but sagittal parameters were more closely correlated to photographic parameters than coronal measurements. TPA and CPA had the strongest associations with their photographic equivalents (both r2 = 0.59, p < 0.001). Radiographic and clinical parameters tended to be more strongly correlated in the low-BMI group. Clinical measures of TPA and CPA had high intraobserver reliability (all ICC > 0.99, p < 0.001) and interobserver reliability (both ICC > 0.99, p < 0.001).

CONCLUSIONS

The photographic measures of spinal deformity developed in this study were highly correlated with their radiographic counterparts and had high inter- and intraobserver reliability. Clinical photography can not only reduce radiation exposure in patients with adult spinal deformity, but also be used to assess deformity when full-spine radiographs are unavailable.

Intraoperative versus postoperative radiographic coronal balance for adult spinal deformity surgery

BACKGROUND

Coronal malalignment in adult spinal deformity (ASD) has a close relationship with patient clinical outcomes. The purpose of this study is to evaluate the relationship between intra- and postoperative coronal radiographic parameters. A novel parameter, the central sacral pelvic line (CSPL), and its relation to the central sacral vertical line (CSVL) is explored. CSPL is a measure of spinal alignment referenced to the patient's pelvis as an intraoperative proxy for CSVL. CSVL is difficult to measure intraoperatively, because a C7-plumb line (referenced to gravity) cannot be drawn in the supine position.

METHODS

47 subjects ≥ 18 years old undergoing a spinal fusion of ≥ 6 levels from 2015 to 2017 were enrolled. The CSPL is defined as the perpendicular line bisecting the midpoint of the line that connects the superior aspects of the acetabuli. Two metrics describing coronal alignment were derived from each radiograph: (1) horizontal distance between the C7-plumb line and the CSPL at C7 (C7-CSPL) and (2) horizontal distance between the C7-plumb line and CSVL (C7-CSVL). Pearson's correlation and linear regression analysis was used to study the relationship between the intraoperative C7-CSPL and the postoperative C7-CSVL.

RESULTS

On average, the intraoperative C7-CSPL distance was 32.1 mm, postoperative C7-CSPL 20.8 mm, and postoperative C7-CSVL 18.9 mm. 15/47 (32%) had intraoperative C7-CSPL measurements > 4 cm, requiring intraoperative correction. Of those 15, 10 patients (67%) still had a postoperative C7-CSVL < 4 cm. Linear regression modeling indicates that when intraoperative CSPL is < 7.7 cm on average, the postoperative C7-CSVL will < 4 cm-our threshold for adequate coronal alignment. Patients with intraoperative C7-CSPL > 5 cm had a 50% chance of having a postoperative C7-CSVL > 4 cm; patients with intraoperative C7-CSPL < 5 cm had a 3% chance of having coronal malalignment. There is a strong positive relationship between postoperative C7-CSPL and C7-CSVL (r = 0.80 and 0.85, respectively).

CONCLUSION

In adult spinal surgery, the intraoperative coronal alignment measured using the novel C7-CSPL distance correlates well with postoperative C7-CSVL distance. This gives the surgeon an objective measurement of the correction they need after assessing initial intraoperative imaging. Our findings suggest an intraoperative C7-CSPL distance < 5 cm as a threshold value to predict postoperative C7-CSVL < 4 cm in 97% of patients tested.

Sagittal spine shape literacy in the general adult population, assessed by a novel, simple graphical tool

[Purpose] The sagittal shape of the spine is associated with back-pain, balance and quality of life. We developed, evaluated and report the responses of a graphical tool to assess sagittal spine shape knowledge (literacy). [Participants and Methods] Two hundred and fifty adults were randomly assigned, in a cross-sectional crossover study, to free-hand draw and select the “ideal” sagittal spine shape. We evaluated the inter and intra-rater reliability and agreement between tests and the sagittal and lordotic spine literacy between the drawing and selection test versions. [Results] Drawing test inter- and intra-rater agreement was 79% and 80% respectively. Drawing vs. selection agreement was 43%. More participants drew than selected the correct spine (30% vs. 21%) (p<0.001) and lumbar lordosis shape (56% vs. 42%) (p<0.001). Test order did not affect spine shape literacy scores. A significantly poorer literacy trend was observed with spine pain presence (p=0.02). [Conclusion] We developed a reliable method to evaluate spine shape literacy and established that only 21% and 42% of our sample demonstrated correct sagittal spine and lordotic spine shape literacy, respectively. The low literacy scores suggests that consideration of including spine shape literacy in health literacy and self-management programs may be warranted, especially in ageing populations.

Outcomes of Surgical Treatment for One Hundred Thirty-Eight Patients With Severe Sagittal Deformity at a Minimum 2-Year Follow-up: A Case Series

BACKGROUND

Operative treatment of adult spinal deformity (ASD) can be very challenging with high complication rates. It is well established that patients benefit from such treatment; however, the surgical outcomes for patients with severe sagittal deformity have not been reported.

OBJECTIVE

To report the outcomes of patients undergoing surgical correction for severe sagittal deformity.

METHODS

Retrospective review of a prospective, multicenter ASD database. Inclusion criteria: operative patients age ≥18, sagittal vertical axis (SVA) ≥15 cm, mismatch between pelvic incidence and lumbar lordosis (PI-LL) ≥30°, and/or lumbar kyphosis ≥5° with minimum 2 yr follow-up. Health-related quality of life (HRQOL) scores including minimal clinically important difference (MCID)/substantial clinical benefit (SCB), sagittal and coronal radiographic values, demographic, frailty, surgical, and complication data were collected. Comparisons between 2 yr postoperative and baseline HRQOL/radiographic data were made. P < .05 was significant.

RESULTS

A total of 138 patients were included from 502 operative patients (54.3% Female, Average (Avg) age 63.3 ± 11.5 yr). Avg operating room (OR) time 386.2 ± 136.5 min, estimated blood loss (EBL) 1829.8 ± 1474.6 cc. A total of 71(51.4%) had prior fusion. A total of 89.9% were posterior fusion only. Mean posterior levels fused 11.5 ± 4.1. A total of 44.9% had a 3-column osteotomy. All 2 yr postoperative radiographic parameters were significantly improved compared to baseline (P < .001 for all). All 2yr HRQOL measures were significantly improved compared to baseline (P < .004 for all). A total of 46.6% to 73.8% of patients met either MCID/SCB for all HRQOL. A total of 74.6% of patients had at least 1 complication, 11.6% had 4 or more complications, 33.3% had minimum 1 major complication, and 42(30.4%) had a postop revision.

CONCLUSION

Patients with severe sagittal malalignment benefit from surgical correction at 2 yr postoperative both radiographically and clinically despite having a high complication rate.