Change in classification grade by the SRS-Schwab Adult Spinal Deformity Classification predicts impact on health-related quality of life measures: prospective analysis of operative and nonoperative treatment

Analysis of the reliability of surgeons' ability to differentiate between idiopathic and degenerative spinal deformity in adults radiologically. What descriptive parameters help them decide?

PURPOSE

Adult spinal deformity (ASD) may be classified as idiopathic (ID) or degenerative (DD) (or other) based on classifier's perception, the reliability of and factors inherent to which remain unknown. The aim of this study is to evaluate the inter- and intra-observer reliability of surgeons' perception in differentiating ID from DD and to identify the determinants of this differentiation.

METHODS

From a multicentric prospective database of ASD, 179 patients were identified with the diagnosis of ID (n = 103) or DD (n = 76); without previous surgery; and a lumbar coronal curve larger than 20°. Standing antero-posterior and lateral X-rays of these patients were sent to five experienced spine surgeons to be identified as DD or ID (or other); followed by a second round after reshuffling. Weighted kappa statistics were used, the strength of agreement for the kappa coefficient was considered as; 0.81-1 = almost perfect, 0.61-0.8 = substantial, 0.41-0.60 = moderate, 0.21-0.40 = fair, 0.01-0.20 = slight, and ≤0 = poor. Patients were then stratified based on the number of agreements on a total of 10 rounds as excellent (10 out of 10), good (more than 7 out of 10) and fair/poor (7 and less). These excellent and good agreements were further compared for additional radiological parameters.

RESULTS

Agreement levels were moderate to substantial for intra but mostly fair for inter-observer comparisons. For ID patients, there were 42 cases with excellent and 38 with very good agreement whereas for DD, there were no excellent and only 17 cases with very good agreement. Upon comparison of these (ID vs DD for at least very good cases), it was seen that they were different for some coronal parameters such as lumbar Cobb angle (larger in ID, p < 0.001), central sacral vertical line (CSVL) modifier (C more common in ID, p = 0.007) and presence of rotatory subluxation (less common in DD, p = 0.017), but very different for sagittal parameters (lumbar lordosis, sagittal vertical axis, T2 sagittal tilt, pelvic tilt, sacral slope, and global tilt; increased sagittal imbalance in DD, all p ≤ 0.001).

CONCLUSION

Surgeons in this study demonstrated reasonable (moderate to substantial) intra-observer agreement, but only fair agreement amongst them. Alarming as it may appear, we should be cautious in interpreting these results based on only radiology and no clinical information. In patients with good agreement, the most consistent radiologic determinant of degenerative ASD appeared to be the presence of sagittal imbalance.

Prevalence and type of cervical deformities among adults with Parkinson's disease: a cross-sectional study

OBJECT

To identify the characteristics of cervical deformities in Parkinson's disease (PD) and the role of severity of PD in the development of cervical spine deformities, the authors investigated the prevalence of the cervical deformities, cervical kyphosis (CK), and cervical positive sagittal malalignment (CPSM) in patients with PD. They also analyzed the association of severity of cervical deformities with the stage of PD in the context of global sagittal spinopelvic alignment.

METHODS

This study was a prospective assessment of consecutively treated patients (n = 89) with PD. A control group of the age- and sex-matched patients was selected from patients with degenerative cervical spine disease but without PD. Clinical and demographic parameters including age, sex, duration of PD, and Hoehn and Yahr (H&Y) stage were collected. Full-length standing radiographs were used to assess spinopelvic parameters. CK was defined as a C2-7 Cobb angle < 0°. CPSM was defined as C2-7 sagittal vertical axis (SVA) > 4 cm.

RESULTS

A significantly higher prevalence of CPSM (28% vs. 1.1%, p < 0.001), but not CK (12% vs. 10.1%, p = 0.635), was found in PD patients compared with control patients. Among patients with PD, those with CK were younger (62.1 vs. 69.0 years, p = 0.013) and had longer duration of PD (56.4 vs. 36.2 months, p = 0.034), but the severity of PD was not significantly different. Logistic regression analysis revealed that the presence of CK was associated with younger age, higher mismatch between pelvic incidence and lumbar lordosis, and lower C7-S1 SVA. The patients with CPSM had significantly greater thoracic kyphosis (TK) (p < 0.001) and a trend toward more advanced H&Y stage (p = 0.05). Logistic regression analysis revealed that CPSM was associated with male sex, greater TK, and more advanced H&Y stage.

CONCLUSIONS

Patients with PD have a significantly higher prevalence of CPSM compared with age- and sex-matched control patients with cervical degenerative disease but without PD. Among patients with PD, CK is not associated with the severity of PD but is associated with overall global sagittal malalignment. In contrast, the presence of CPSM is associated more with the severity of PD than it is with the presence of global sagittal malalignment. Collectively, these data suggest that the neuromuscular pathogenesis of PD may affect the development of CPSM more than of CK.

Reliability assessment of a novel cervical spine deformity classification system

OBJECT

Despite the complexity of cervical spine deformity (CSD) and its significant impact on patient quality of life, there exists no comprehensive classification system. The objective of this study was to develop a novel classification system based on a modified Delphi approach and to characterize the intra- and interobserver reliability of this classification.

METHODS

Based on an extensive literature review and a modified Delphi approach with an expert panel, a CSD classification system was generated. The classification system included a deformity descriptor and 5 modifiers that incorporated sagittal, regional, and global spinopelvic alignment and neurological status. The descriptors included: “C,” “CT,” and “T” for primary cervical kyphotic deformities with an apex in the cervical spine, cervicothoracic junction, or thoracic spine, respectively; “S” for primary coronal deformity with a coronal Cobb angle ≥ 15°; and “CVJ” for primary craniovertebral junction deformity. The modifiers included C2–7 sagittal vertical axis (SVA), horizontal gaze (chin-brow to vertical angle [CBVA]), T1 slope (TS) minus C2–7 lordosis (TS–CL), myelopathy (modified Japanese Orthopaedic Association [mJOA] scale score), and the Scoliosis Research Society (SRS)-Schwab classification for thoracolumbar deformity. Application of the classification system requires the following: 1) full-length standing posteroanterior (PA) and lateral spine radiographs that include the cervical spine and femoral heads; 2) standing PA and lateral cervical spine radiographs; 3) completed and scored mJOA questionnaire; and 4) a clinical photograph or radiograph that includes the skull for measurement of the CBVA. A series of 10 CSD cases, broadly representative of the classification system, were selected and sufficient radiographic and clinical history to enable classification were assembled. A panel of spinal deformity surgeons was queried to classify each case twice, with a minimum of 1 intervening week. Inter- and intrarater reliability measures were based on calculations of Fleiss k coefficient values.

RESULTS

Twenty spinal deformity surgeons participated in this study. Interrater reliability (Fleiss k coefficients) for the deformity descriptor rounds 1 and 2 were 0.489 and 0.280, respectively, and mean intrarater reliability was 0.584. For the modifiers, including the SRS-Schwab components, the interrater (round 1/round 2) and intrarater reliabilities (Fleiss k coefficients) were: C2–7 SVA (0.338/0.412, 0.584), horizontal gaze (0.779/0.430, 0.768), TS-CL (0.721/0.567, 0.720), myelopathy (0.602/0.477, 0.746), SRS-Schwab curve type (0.590/0.433, 0.564), pelvic incidence-lumbar lordosis (0.554/0.386, 0.826), pelvic tilt (0.714/0.627, 0.633), and C7-S1 SVA (0.071/0.064, 0.233), respectively. The parameter with the poorest reliability was the C7–S1 SVA, which may have resulted from differences in interpretation of positive and negative measurements.

CONCLUSIONS

The proposed classification provides a mechanism to assess CSD within the framework of global spinopelvic malalignment and clinically relevant parameters. The intra- and interobserver reliabilities suggest moderate agreement and serve as the basis for subsequent improvement and study of the proposed classification.

The National Neurosurgery Quality and Outcomes Database Qualified Clinical Data Registry: 2015 measure specifications and rationale

Meaningful quality measurement and public reporting have the potential to facilitate targeted outcome improvement, practice-based learning, shared decision making, and effective resource utilization. Recent developments in national quality reporting programs, such as the Centers for Medicare & Medicaid Services Qualified Clinical Data Registry (QCDR) reporting option, have enhanced the ability of specialty groups to develop relevant quality measures of the care they deliver. QCDRs will complete the collection and submission of Physician Quality Reporting System (PQRS) quality measures data on behalf of individual eligible professionals. The National Neurosurgery Quality and Outcomes Database (N2QOD) offers 21 non-PQRS measures, initially focused on spine procedures, which are the first specialty-specific measures for neurosurgery. Securing QCDR status for N2QOD is a tremendously important accomplishment for our specialty. This program will ensure that data collected through our registries and used for PQRS is meaningful for neurosurgeons, related spine care practitioners, their patients, and other stakeholders. The 2015 N2QOD QCDR is further evidence of neurosurgery’s commitment to substantively advancing the health care quality paradigm. The following manuscript outlines the measures now approved for use in the 2015 N2QOD QCDR. Measure specifications (measure type and descriptions, related measures, if any, as well as relevant National Quality Strategy domain[s]) along with rationale are provided for each measure.

Clinical Improvement Through Surgery for Adult Spinal Deformity: What Can Be Expected and Who Is Likely to Benefit Most?

STUDY DESIGN

Multicenter, prospective, nonconsecutive, surgical case series from the International Spine Study Group.

OBJECTIVES

To evaluate the extent of clinical improvement after surgery for adult spinal deformity (ASD) based on minimal clinically important difference (MCID) and baseline measures.

SUMMARY OF BACKGROUND DATA

For ASD, evaluation of surgical treatment success using clinical scores should take into account baseline disability and pain and the improvement defined relative to the MCID.

METHODS

Inclusion criteria included operative patients (age >18 years) with baseline and 2-year SRS-22 scores. Normative values for the SRS scores were included and improvement for patients was expressed in number of MCIDs. At baseline, patients were classified by differences in activity and pain scores from normative values in four groups: "worst," "severe," "poor," and, "moderate." At 2 years after surgery, patients were classified into four groups based on their change in SRS score as follows: "no improvement or deterioration," "mediocre," "satisfactory," or "optimal." Distinction among curve types was also performed based on the SRS-Schwab ASD classification.

RESULTS

A total of 223 patients (age = 55 ± 15 years) were included. At baseline, for 77% of the patients, the worst scores were in Activity or Pain. At baseline, the distribution was 36% "worst," 28% "severe," 19% "poor," and 17% "moderate." Patients with sagittal malalignment only were more likely to be in the "worst" state (54%). The overall distribution of improvement was as follows: 24% no improvement or deterioration, 17% mediocre, 25% satisfactory, and 33% optimal. Forty-one percent of baseline "moderate" patients achieved no improvement. Of the baseline "worst" patients, 20% achieved no improvement, and 36% and 19% achieved "satisfactory" and "optimal" improvement, respectively.

CONCLUSION

Overall, 24% of patients did not experience improvement after surgery. Patients with baseline severe disability were more likely to perceive improvement than patients with less disability.

LEVEL OF EVIDENCE

Level II.

Volume and fat infiltration of spino-pelvic musculature in adults with spinal deformity

AIM: To investigate fat infiltration and volume of spino-pelvic muscles in adults spinal deformity (ASD) with magnetic resonance imaging (MRI) and 3D reconstructions.

METHODS: Nineteen female ASD patients (mean age 60 ± 13) were included prospectively and consecutively and had T1-weighted Turbo Spin Echo sequence MRIs with Dixon method from the proximal tibia up to T12 vertebra. The Dixon method permitted to evaluate the proportion of fat inside each muscle (fat-water ratio). In order to investigate the accuracy of the Dixon method for estimating fat vs water, the same MRI acquisition was performed on phantoms of four vials composed of different proportion of fat vs water. With Muscl’X software, 3D reconstructions of 17 muscles or group of muscles were obtained identifying the muscle’s contour on a limited number of axial images [Deformation of parametric specific objects (DPSO) Method]. Musclar volume (Vmuscle), infiltrated fat volume (Vfat) and percentage of fat infiltration [Pfat, calculated as follow: Pfat = 100 × (Vfat/Vmuscle)] were characterized by extensor or flexor function respectively for the spine, hip and knee and theirs relationship with demographic data were investigated.

RESULTS: Phantom acquisition demonstrated a non linear relation between Dixon fat-water ratio and the real fat-water ratio. In order to correct the Dixon fat-water ratio, the non linear relation was approximated with a polynomial function of degree three using the phantom acquisition. On average, Pfat was 13.3% ± 5.3%. Muscles from the spinal extensor group had a Pfat significantly greater than the other muscles groups, and the largest variability (Pfat = 31.9% ± 13.8%, P < 0.001). Muscles from the hip extensor group ranked 2^nd in terms of Pfat (14% ± 8%), and were significantly greater than those of the knee extensor (P = 0.030). Muscles from the knee extensor group demonstrated the least Pfat (12% ± 8%). They were also the only group with a significant correlation between Vmuscle and Pfat (r = -0.741, P < 0.001), however this correlation was lacking in the other groups. No correlation was found between the Vmuscle total and age or body mass index. Except for the spine flexors, Pfat was correlated with age. Vmuscle and Vfat distributions demonstrated that muscular degeneration impacted the spinal extensors most.

CONCLUSION: Mechanisms of fat infiltration are not similar among the muscle groups. Degeneration impacted the spinal and hip extensors most, key muscles of the sagittal alignment.

Radiographical and Implant-Related Complications in Adult Spinal Deformity Surgery: Incidence, Patient Risk Factors, and Impact on Health-Related Quality of Life

STUDY DESIGN

A multicenter, prospective review of surgical patients with adult spine deformity.

OBJECTIVE

Assessment of the incidence, risk factor, and impact of radiographical and implant-related complications (RIC) on health-related quality of life measures.

SUMMARY OF BACKGROUND DATA

This study provides assessment of the incidence of RIC in adult spinal deformity surgery and impact of these complications on need for reoperation. Risk factors for development of RIC are also assessed, as well as the impact of these complications on health-related quality of life (HRQOL) outcomes measures.

METHODS

A multicenter, prospective database of surgical patients with adult spinal deformity was reviewed. All patients with complete 2-year follow-up were included. HRQOL was measured using the Oswestry Disability Index, General Health Survey (36-Item Short Form Health Survey [SF-36]), and Scoliosis Research Society-22 (SRS-22r) at baseline, 6 weeks, 1 year, and 2 years postoperatively. Univariate testing was performed as appropriate. Multivariate logistic regression modeling was used to determine independent predictors of RIC. Multivariate repeated-measures mixed models were used to examine HRQOL, accounting for confounders.

RESULTS

A total of 245 patients met inclusion criteria. The incidence of RIC was 31.7% and 52.6% of those patients required reoperation. Rod breakage accounted for 47% of the implant-related complications, and proximal junctional kyphosis accounted for 54.5% of radiographical complications. Univariate analysis identified the following potential risk factors for RIC: weight, American Society of Anesthesiologists score, revision, stopping the fusion in the lower thoracic spine, worse SRS-Schwab classification modifiers (pelvic tilt++, pelvic incidence minus lumbar lordosis++, sagittal vertical axis++), higher T1 spinopelvic inclination, and higher T1 slope. Independent predictors of RIC as identified on multivariate logistic regression included American Society of Anesthesiologists (odds ratio: 1.75, P = 0.029) and sagittal vertical axis modifier ++ (odds ratio 3.43, P = 0.0001). The RIC and no RIC groups each experienced significant improvement over time, as measured on the Oswestry Disability Index (P = 0.0001), SF-36 (P = 0.0001), and SRS-22r (P = 0.0001). However, the rate of improvement over time was less for patients with RIC (SRS-22r P = 0.043, SF-36 P = 0.0001).

CONCLUSION

This study identified that nearly one-third of patients undergoing adult spinal deformity surgery experienced a radiographical or implant-related complication, and that just more than one-half of these patients experiencing complication required a reoperation within 2 years of surgery. These complications significantly affected HRQOL measures. Baseline patient characteristics and parameters of the SRS-Schwab classification can be used to help identify those patients at greater risk.

LEVEL OF EVIDENCE

3.

The likelihood of reaching minimum clinically important difference and substantial clinical benefit at 2 years following a 3-column osteotomy: analysis of 140 patients

OBJECT

Three-column osteotomies (3COs) are technically challenging techniques for correcting severe rigid spinal deformities. The impact of these interventions on outcomes reaching minimum clinically important difference (MCID) or substantial clinical benefit (SCB) is unclear. The objective of this study was to determine the rates of MCID and SCB in standard health-related quality of life (HRQOL) measures after 3COs in patients with adult spinal deformity (ASD). The impacts of location of the uppermost instrumented vertebra (UIV) on clinical outcomes and of maintenance on sagittal correction at 2 years postoperatively were also examined.

METHODS

The authors conducted a retrospective multicenter analysis of the records from adult patients who underwent 3CO with complete 2-year radiographic and clinical follow-ups. Cases were categorized according to established radiographic thresholds for pelvic tilt (> 22°), sagittal vertical axis (> 4.7 cm), and the mismatch between pelvic incidence and lumbar lordosis (> 11°). The cases were also analyzed on the basis of a UIV in the upper thoracic (T1–6) or thoracolumbar (T9–L1) region. Patient-reported outcome measures evaluated preoperatively and 2 years postoperatively included Oswestry Disability Index (ODI) scores, the Physical Component Summary and Mental Component Summary (MCS) scores of the 36-Item Short Form Health Survey, and Scoliosis Research Society-22 questionnaire (SRS-22) scores. The percentages of patients whose outcomes for these measures met MCID and SCB were compared among the groups.

RESULTS

Data from 140 patients (101 women and 39 men) were included in the analysis; the average patient age was 57.3 ± 12.4 years (range 20–82 years). Of these patients, 94 had undergone only pedicle subtraction osteotomy (PSO) and 42 only vertebral column resection (VCR); 113 patients had a UIV in the upper thoracic (n = 63) orthoracolumbar region (n = 50). On average, 2 years postoperatively the patients had significantly improved in all HRQOL measures except the MCS score. For the entire patient cohort, the improvements ranged from 57.6% for the SRS-22 pain score MCID to 24.4% for the ODI score SCB. For patients undergoing PSO or VCR, the likelihood of their outcomes reaching MCID or SCB ranged from 24.3% to 62.3% and from 16.2% to 47.8%, respectively. The SRS-22 self-image score of patients who had a UIV in the upper thoracic region reached MCID significantly more than that of patients who had a UIV in the thoracolumbar region (70.6% vs 41.9%, p = 0.0281). All other outcomes were similar for UIVs of upper thoracic and thoracolumbar regions. Comparison of patients whose spines were above or below the radiographic thresholds associated with disability indicated similar rates of meeting MCID and SCB for HRQOL at the 2-year follow-up.

CONCLUSIONS

Outcomes for patients having UIVs in the upper thoracic region were no more likely to meet MCID or SCB than for those having UIVs in the thoracolumbar region, except for the MCID in the SRS-22 self-image measure. The HRQOL outcomes in patients who had optimal sagittal correction according to radiographic thresholds determined preoperatively were not significantly more likely to reach MCID or SCB at the 2-year follow-up. Future work needs to determine whether the Schwab preoperative radiographic thresholds for severe disability apply in postoperative settings.

Comparison of best versus worst clinical outcomes for adult spinal deformity surgery: a retrospective review of a prospectively collected, multicenter database with 2-year follow-up

OBJECT

Although recent studies suggest that average clinical outcomes are improved following surgery for selected adult spinal deformity (ASD) patients, these outcomes span a broad range. Few studies have specifically addressed factors that may predict favorable clinical outcomes. The objective of this study was to compare patients with ASD with best versus worst clinical outcomes following surgical treatment to identify distinguishing factors that may prove useful for patient counseling and optimization of clinical outcomes.

METHODS

This is a retrospective review of a prospectively collected, multicenter, database of consecutively enrolled patients with ASD who were treated operatively. Inclusion criteria were age > 18 years and ASD. For patients with a minimum of 2-year follow-up, those with best versus worst outcomes were compared separately based on Scoliosis Research Society-22 (SRS-22) and Oswestry Disability Index (ODI) scores. Only patients with a baseline SRS-22 ≤ 3.5 or ODI ≥ 30 were included to minimize ceiling/floor effects. Best and worst outcomes were defined for SRS-22 (≥ 4.5 and ≤ 2.5, respectively) and ODI (≤ 15 and ≥ 50, respectively).

RESULTS

Of 257 patients who met the inclusion criteria, 227 (88%) had complete baseline and 2-year follow-up SRS-22 and ODI outcomes scores and radiographic imaging and were analyzed in the present study. Of these 227 patients, 187 had baseline SRS-22 scores ≤ 3.5, and 162 had baseline ODI scores ≥ 30. Forthe SRS-22, best and worst outcomes criteria were met at follow-up for 25 and 27 patients, respectively. For the ODI, best and worst outcomes criteria were met at follow-up for 43 and 51 patients, respectively. With respect to the SRS-22, compared with best outcome patients, those with worst outcomes had higher baseline SRS-22 scores (p < 0.0001), higher prevalence of baseline depression (p < 0.001), more comorbidities (p = 0.012), greater prevalence of prior surgery (p = 0.007), a higher complication rate (p = 0.012), and worse baseline deformity (sagittal vertical axis [SVA], p = 0.045; pelvic incidence [PI] and lumbar lordosis [LL] mismatch, p = 0.034). The best-fit multivariate model for SRS-22 included baseline SRS-22 (p = 0.033), baseline depression (p = 0.012), and complications (p = 0.030). With respect to the ODI, compared with best outcome patients, those with worst outcomes had greater baseline ODI scores (p < 0.001), greater baseline body mass index (BMI; p = 0.002), higher prevalence of baseline depression (p < 0.028), greater baseline SVA (p = 0.016), a higher complication rate (p = 0.02), and greater 2-year SVA (p < 0.001) and PI-LL mismatch (p = 0.042). The best-fit multivariate model for ODI included baseline ODI score (p < 0.001), 2-year SVA (p = 0.014) and baseline BMI (p = 0.037). Age did not distinguish best versus worst outcomes for SRS-22 or ODI (p > 0.1).

CONCLUSIONS

Few studies have specifically addressed factors that distinguish between the best versus worst clinical outcomes for ASD surgery. In this study, baseline and perioperative factors distinguishing between the best and worst outcomes for ASD surgery included several patient factors (baseline depression, BMI, comorbidities, and disability), as well as residual deformity (SVA), and occurrence of complications. These findings suggest factors that may warrant greater awareness among clinicians to achieve optimal surgical outcomes for patients with ASD.

Comprehensive study of back and leg pain improvements after adult spinal deformity surgery: analysis of 421 patients with 2-year follow-up and of the impact of the surgery on treatment satisfaction

OBJECT

Back and leg pain are the primary outcomes of adult spinal deformity (ASD) and predict patients' seeking of surgical management. The authors sought to characterize changes in back and leg pain after operative or nonoperative management of ASD. Outcomes were assessed according to pain severity, type of surgical procedure, Scoliosis Research Society (SRS)–Schwab spine deformity class, and patient satisfaction.

METHODS

This study retrospectively reviewed data in a prospective multicenter database of ASD patients. Inclusion criteria were the following: age > 18 years and presence of spinal deformity as defined by a scoliosis Cobb angle ≥ 20°, sagittal vertical axis length ≥ 5 cm, pelvic tilt angle ≥ 25°, or thoracic kyphosis angle ≥ 60°. Patients were grouped into nonoperated and operated subcohorts and by the type of surgical procedure, spine SRS-Schwab deformity class, preoperative pain severity, and patient satisfaction. Numerical rating scale (NRS) scores of back and leg pain, Oswestry Disability Index (ODI) scores, physical component summary (PCS) scores of the 36-Item Short Form Health Survey, minimum clinically important differences (MCIDs), and substantial clinical benefits (SCBs) were assessed.

RESULTS

Patients in whom ASD had been operatively managed were 6 times more likely to have an improvement in back pain and 3 times more likely to have an improvement in leg pain than patients in whom ASD had been nonoperatively managed. Patients whose ASD had been managed nonoperatively were more likely to have their back or leg pain remain the same or worsen. The incidence of postoperative leg pain was 37.0% at 6 weeks postoperatively and 33.3% at the 2-year follow-up (FU). At the 2-year FU, among patients with any preoperative back or leg pain, 24.3% and 37.8% were free of back and leg pain, respectively, and among patients with severe (NRS scores of 7–10) preoperative back or leg pain, 21.0% and 32.8% were free of back and leg pain, respectively. Decompression resulted in more patients having an improvement in leg pain and their pain scores reaching MCID. Although osteotomies improved back pain, they were associated with a higher incidence of leg pain. Patients whose spine had an SRS-Schwab coronal curve Type N deformity (sagittal malalignment only) were least likely to report improvements in back pain. Patients with a Type L deformity were most likely to report improved back or leg pain and to have reductions in pain severity scores reaching MCID and SCB. Patients with a Type D deformity were least likely to report improved leg pain and were more likely to experience a worsening of leg pain. Preoperative pain severity affected pain improvement over 2 years because patients who had higher preoperative pain severity experienced larger improvements, and their changes in pain severity were more likely to reach MCID/SCB than for those reporting lower preoperative pain. Reductions in back pain contributed to improvements in ODI and PCS scores and to patient satisfaction more than reductions in leg pain did.

CONCLUSIONS

The authors' results provide a valuable reference for counseling patients preoperatively about what improvements or worsening in back or leg pain they may experience after surgical intervention for ASD.

Cervical sagittal alignment in idiopathic scoliosis treated by posterior instrumentation and in situ bending

STUDY DESIGN

Retrospective radiographical analysis of cervical and thoracolumbar sagittal alignment in young adults with idiopathic scoliosis.

OBJECTIVE

To analyze cervical alignment types, the relationship between cervical and thoracolumbar alignment and the effect of posterior instrumentation.

SUMMARY OF BACKGROUND DATA

Thoracic scoliosis with hypokyphosis may decrease cervical lordosis. Additional adaptive positional changes of the mobile cervical segment may exist, because sigmoid cervical patterns are observed. Sagittal alignment of the instrumented thoracolumbar spine may influence cervical alignment.

METHODS

Pre- and postoperative full-spine radiographs of 52 patients were analyzed at 8-year average follow-up. Sagittal thoracolumbar measurements were T1 slope, T1-T4 kyphosis, T4-T12 kyphosis, L1-S1 lordosis, pelvic incidence, pelvic tilt, sacral slope, sagittal vertical axis (SVA) C7, and SVA C2. Cervical measurements were C0-C2, C2-C6, C2-C4, C4-C6, and C2-T1 lordosis, chin-brow vertical angle.

RESULTS

Five cervical alignment types were identified: lordotic, hypolordotic, kyphotic, sigmoid with cranial lordosis, and sigmoid with cranial kyphosis. Spinopelvic parameters and global thoracolumbar balance remained unchanged postoperatively. The average C2-C6 lordosis increased by 6.4° (P < 0.0001). Twenty-seven of the 52 patients changed cervical alignment postoperatively. SVA C2-C7 difference changed in this subgroup (P = 0.0159). In 21 of the 27 patients, SVA changed more than 5 mm at C2 (P = 0.0029), and in 25 of the 27 patients at C7 (P < 0.0001). A correlation existed between T4-T12 kyphosis and L1-S1 lordosis, C2-C4 and L1-S1 lordosis, L1-S1 lordosis, and pelvic tilt. T1-T4 kyphosis and T1 slope correlated with C2-T1 lordosis, but proximal junctional kyphosis was not linked to a specific cervical alignment type.

CONCLUSION

Postoperative adaptive changes occurred at C7 and C2 by shifting anteriorly or posteriorly, resulting in different radiographical cervical shapes. The amount of lumbar lordosis may influence cervical lordosis, which needs to be considered for surgical correction. Adaptive hip movements may influence thoracolumbar and cervical alignment. The amount of proximal thoracic kyphosis influenced cervical lordosis. Global thoracic hypokyphosis might influence cervical alignment, but it was not evidenced.

LEVEL OF EVIDENCE

4.

Radiographic outcomes of anterior column realignment for adult sagittal plane deformity: a multicenter analysis

PURPOSE

Anterior column reconstruction (ACR) is a minimally invasive technique for the treatment of sagittal plane deformity. ACR uses a lateral transpsoas approach with ALL release and the application of an interbody device to achieve correction. Here, we present 1-year radiographic results from a multicenter study of adult spinal deformity (ASD) patients.

METHODS

A multicenter database was queried from 2005 to 2013 for ASD patients treated with ACR. Demographics, surgical data, and radiographic measurements were collected and retrospectively analyzed. Radiographic time points included preoperative (pre-op), postoperative (post-op; first visit prior to 3 months), and last follow-up (last FU; minimum of 1 year). Sagittal radiographic measurements included regional lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), T1 spinopelvic inclination (T1SPi), and segmental lordosis (disc angle).

RESULTS

Mean patient age was 67.4 years (range 46.5-80.0) and 11 patients (32.4 %) were male. Twenty patients (58.8 %) had previous lumbar surgery. All patients had a minimal of one-level ACR with ALL release (mean 1.7; range 1-4). Mean number of lateral interbody fusion (LLIF) levels without ALL release per patient was 0.7 (range 0-3). Thirty-three patients (97.1 %) received supplemental posterior fixation and 1 patient (2.9 %) had lateral fixation only. In 26 patients (76.5 %), supplemental posterior fixation was performed using an open approach, and 7 patients (20.6 %) were treated with percutaneous placement. Mean of number of levels fused was 7.1 (range 2-16). There was a significant improvement in LL (p < 0.001), PI-LL mismatch (p < 0.001), and PT (p = 0.03) from pre-op to post-op, and pre-op to last FU. There was no change in T1SPi, SS, or PI. Segmental lordosis improved at ACR levels from mean of -2.2° pre-op to -16.0° post-op (p < 0.01) and -16.3° at last FU (p < 0.001). The addition of posterior column osteotomy increased the change in segmental lordosis with ACR by 72.7 % (p < 0.001). LLIF without ALL release led to significant improvement in segmental lordosis from pre-op (-2.4°) to post-op (-7.1°; p < 0.01) but not from pre-op to last FU (-5.7°; p = 0.06).

CONCLUSION

ACR successfully restores lumbar lordosis in ASD patients with sagittal imbalance. ACR results in greater segmental correction than is achieved with LLIF alone. Supplementing with posterior osteotomies allows for even greater correction. The ability to achieve the desired radiographic goals is expected to improve as technical nuances are refined and patient selection is optimized.

Will immediate postoperative imbalance improve in patients with thoracolumbar/lumbar degenerative kyphoscoliosis? A comparison between Smith-Petersen osteotomy and pedicle subtraction osteotomy with an average 4 years of follow-up

STUDY DESIGN

A retrospective radiographical study.

OBJECTIVE

To compare compensatory behavior of coronal and sagittal alignment after pedicle subtraction osteotomy (PSO) and Smith-Petersen osteotomy (SPO) for degenerative kyphoscoliosis.

SUMMARY OF BACKGROUND DATA

There was a paucity of literature paying attention to the postoperative imbalance after PSO or SPO and natural evolution of the imbalance.

METHODS

A retrospective study was performed on 68 consecutive patients with degenerative kyphoscoliosis treated by lumbar PSO (25 patients) or SPO (43 patients) procedures at a single institution. Long-cassette standing radiographs were taken preoperatively, postoperatively, and at the last follow-up and radiographical parameters were measured. The lower instrumented vertebral level and level of osteotomy were compared between the patients with and without improvement.

RESULTS

Negative sagittal vertical axis (SVA) was observed in the PSO group postoperatively, implying an overcorrection of SVA. This negative SVA improved spontaneously during follow-up (P < 0.05). Coronal balance was found to worsen immediately postoperatively in the SPO group (P < 0.05). At the last follow-up, spontaneous improvement was observed in 15 patients and the average coronal balance decreased to 16.35 mm. For the 15 patients with improved coronal balance, fusion at L5 or above was more common compared with the 11 patients with persisted postoperative imbalance (P = 0.027), whereas no difference in term of levels of osteotomy was found (P > 0.05).

CONCLUSION

The overcorrection of SVA is more often seen in the PSO group. The coronal imbalance is more likely to occur in the SPO group. The postoperative sagittal imbalance often spontaneously improves with time. Lower instrumented vertebra at S1 or with pelvic fixation should be regarded as potential risk factors for persistent coronal imbalance in patients with SPO.

LEVEL OF EVIDENCE

3.

Mid- and long-term clinical outcomes of corrective fusion surgery which did not achieve sufficient pelvic incidence minus lumbar lordosis value for adult spinal deformity

Background

Recent studies have demonstrated sagittal spinal balance was more important than coronal balance in terms of clinical result of surgery for adult spinal deformity. Notably, Schwab reported that one of the target spinopelvic parameters for corrective surgery was that pelvic incidence (PI) minus lumbar lordosis (LL) should be within +/- 10 °. The present study aimed to investigate whether the clinical outcome of corrective fusion surgery was really poor for patients who could not acquire sufficient PI-LL value through the surgery.

Methods

The present study included 13 patients (mean 68.5 yrs old) with adult spinal deformity. Inclusion criteria were corrective fusion surgery more than 4 intervertebral levels, PI-LL ≥10° on the whole spine X-ray immediately after surgery, and follow-up period ≥3 years. All surgeries were performed by posterior approach. Parameters using SRS-Schwab classification, proximal junctional kyphosis (PJK) of ≥15°, implants loosening, and non-union were investigated using the total standing spinal X-ray. Clinical outcomes were evaluated by Japanese Orthopaedic Association scores (JOA score), Oswestry Disability Index, SF-36, Visual Analog Scale for low back pain, and satisfaction for surgery using SRS-22 questionnaire.

Results

All patients showed the PI-LL ≥20° before surgery. Although the LL were acquired mean 23.6° after surgery, significant loss of correction was observed at final follow up. The acquired coronal spinal alignment was maintained within the follow-up period. However, sagittal vertical axis (SVA) was shifted forward significantly, from mean 4.5cm immediately after surgery to 11.1cm at final follow-up. Five patients showed PJK, 10 patients showed implants loosening, 8 patients showed non-union at final follow-up. The JOA score and mental health summary measures of SF-36 were significantly improved at final follow-up. The satisfaction score was mean 3.3 points, including 3 patients with ≥4 points, at final follow-up. The satisfaction score correlated negatively with SVA at final follow-up (ρ=-0.58 p=0.03).

Conclusions

The forward shift of SVA was frequently observed, and SVA at final follow-up related to the patient’s satisfaction of surgery. This study indicated the importance of postoperative PI-LL value, but also noted 23% of patients acquired good SVA and satisfaction nevertheless they had inadequate postoperative LL.

Three-column osteotomy surgery versus standard surgical management for the correction of adult spinal deformity: a cohort study

Background

The aim of this study was to analyze and compare the surgical data, clinical outcomes, and complications between three-column osteotomy (3-COS) and standard surgical management (SSM) for the treatment of adult spine deformity (ASD).

Methods

A total of 112 patients who underwent consecutive 3-COS (n = 48) and SSM (n = 64) procedures for ASD correction at a single institution from 2001 to 2011 were reviewed in this study. The outcomes were assessed using the Scoliosis Research Society (SRS)-22 scores. The complications of patients with 3-COS and SSM were also compared.

Results

No significant differences were found in patient characteristics between SSM and 3-COS groups. Surgical data and radiographic parameters showed that the patients of the 3-COS group suffered more severe ASD than those of the SSM group. The distribution of surgical complications revealed that SSM group underwent more complications than 3-COS groups with no significant differences. At final follow-up, the total SRS-22 score of SSM was not significant between pre-operation and post-operation. However, the total SRS-22 score of 3-COS at final follow-up was significantly higher than pre-operation.

Conclusion

For severe ASD patients with high grade pelvic incidence (PI), pelvic tilt (PT), and PI/lumbar lordosis (LL) mismatch and who have subjected to spine surgeries more than twice before, 3-COS might be more effective than SSM in improving the clinical outcomes. However, due to the higher reoperation rate of 3-COS, SSM may be more appropriate than SSM for correcting the not serious ASD patients.

Cervical spine alignment following lumbar pedicle subtraction osteotomy for sagittal imbalance

PURPOSE

The alignment of the cervical spine is of primary importance to maintain horizontal gaze and contributes to the functional outcome of patients. Cervical spine alignment after correction of major sagittal imbalance has rarely been reported in the literature.

METHODS

Retrospective review of 31 consecutive patients with sagittal plane deformities operated by lumbar pedicle subtraction osteotomy. Pre-operative and 3 months post-operative full-length radiographies were analyzed for spinopelvic and cervical-specific parameters.

RESULTS

There was a significant increase in lumbar lordosis (LL), thoracic kyphosis, and sacral slope. There was also a significant decrease in pelvic tilt, pelvic incidence minus LL, knee flexion and sagittal vertical axis. The cervical analysis revealed that there was no significant difference between pre- and post-operative global cervical lordosis (CL) angle and external auditory meatus (EAM) tilt. There was a significant decrease of C7 slope and distal CL, while a significant increase in occipito-C2 (OC2) angle was observed.

CONCLUSION

LL restoration decreased the need of compensation at the pelvis and thoracic spine. The distal CL and C7 slope decreased because there was no need for compensation at this level after the surgery, but the proximal cervical spine takes a slightly flexed position to maintain horizontal sight. EAM tilt measures the head position toward C7, and is close to 0° even in severe cases. Changes of this parameter after surgery are insignificant, probably due to the balance between upper and lower cervical segments; when one of these segments shifts backward the other shifts forward and the result is a balanced head over C7.

An analysis of spinopelvic sagittal alignment after lumbar lordosis reconstruction for degenerative spinal diseases: how much balance can be obtained?

STUDY DESIGN

A retrospective and radiological study of degenerative spinal diseases.

OBJECTIVE

To explore the changes in spinopelvic sagittal alignment after lumbar instrumentation and fusion of degenerative spinal diseases.

SUMMARY OF BACKGROUND DATA

Efforts have been paid to clarify the ideal postoperative sagittal profile for degenerative spinal diseases. However, little has been published about the actual changes of sagittal alignment after lumbar lordosis reconstruction.

METHODS

Radiographical analysis of 83 patients with spinal degeneration was performed by measuring sagittal parameters before and after operations. Comparative studies of sagittal parameters between short (1 level) and long (≥ 2 level) instrumentation and fusion were performed. Different variances (Δ) of these sagittal parameters before and after operations were calculated and compared. Correlative study and linear regression were performed to establish the relationship between variances.

RESULTS

No significant changes were shown in the short-fusion group postoperatively. In the long-fusion group, postoperative lumbar lordosis (LL) and sacral slope (SS) were significantly increased; pelvic tilt (PT), sagittal vertical axis (SVA), pelvic incidence minus lumbar lordosis, and PT/SS were significantly decreased. Different variances of ΔLL, ΔSS, ΔPT, ΔSVA, Δ(pelvic incidence - LL), and ΔPT/SS were significantly greater in the long-fusion group than the short-fusion group. Close correlations were mainly shown among ΔLL, ΔPT, and ΔSVA. Linear regression equations could be developed (ΔPT = -0.185 × ΔLL - 7.299 and ΔSVA = -0.152ΔLL - 1.145).

CONCLUSION

In degenerative spinal diseases, long instrumentation and fusion (≥ 2 levels) provides more efficient LL reconstruction. PT, SS, and SVA improve corresponding to LL in a linear regression model. Linear regression equations could be developed and used to predict PT and SVA change after long instrumentation and fusion for LL reconstruction.

Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity

OBJECT

Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.

METHODS

This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.

RESULTS

Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8).

CONCLUSIONS

Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.

Surgical treatment of pathological loss of lumbar lordosis (flatback) in patients with normal sagittal vertical axis achieves similar clinical improvement as surgical treatment of elevated sagittal vertical axis

Object

Increased sagittal vertical axis (SVA) correlates strongly with pain and disability for adults with spinal deformity. A subset of patients with sagittal spinopelvic malalignment (SSM) have flatback deformity (pelvic incidence–lumbar lordosis [PI-LL] mismatch > 10°) but remain sagittally compensated with normal SVA. Few data exist for SSM patients with flatback deformity and normal SVA. The authors' objective was to compare baseline disability and treatment outcomes for patients with compensated (SVA < 5 cm and PI-LL mismatch > 10°) and decompensated (SVA > 5 cm) SSM.

Methods

The study was a multicenter, prospective analysis of adults with spinal deformity who consecutively underwent surgical treatment for SSM. Inclusion criteria included age older than 18 years, presence of adult spinal deformity with SSM, plan for surgical treatment, and minimum 1-year follow-up data. Patients with SSM were divided into 2 groups: those with compensated SSM (SVA < 5 cm and PI-LL mismatch > 10°) and those with decompensated SSM (SVA ≥ 5 cm). Baseline and 1-year follow-up radiographic and health-related quality of life (HRQOL) outcomes included Oswestry Disability Index, Short Form–36 scores, and Scoliosis Research Society–22 scores. Percentages of patients achieving minimal clinically important difference (MCID) were also assessed.

Results

A total of 125 patients (27 compensated and 98 decompensated) met inclusion criteria. Compared with patients in the compensated group, patients in the decompensated group were older (62.9 vs 55.1 years; p = 0.004) and had less scoliosis (43° vs 54°; p = 0.002), greater SVA (12.0 cm vs 1.7 cm; p < 0.001), greater PI-LL mismatch (26° vs 20°; p = 0.013), and poorer HRQOL scores (Oswestry Disability Index, Short Form-36 physical component score, Scoliosis Research Society-22 total; p ≤ 0.016). Although these baseline HRQOL differences between the groups reached statistical significance, only the mean difference in Short Form–36 physical component score reached threshold for MCID. Compared with baseline assessment, at 1 year after surgery improvement was noted for patients in both groups for mean SVA (compensated –1.1 cm, decompensated +4.8 cm; p ≤ 0.009), mean PI-LL mismatch (compensated 6°, decompensated 5°; p < 0.001), and all HRQOL measures assessed (p ≤ 0.005). No significant differences were found between the compensated and decompensated groups in the magnitude of HRQOL score improvement or in the percentages of patients achieving MCID for each of the outcome measures assessed.

Conclusions

Decompensated SSM patients with elevated SVA experience significant disability; however, the amount of disability in compensated SSM patients with flatback deformity caused by PI-LL mismatch but normal SVA is underappreciated. Surgical correction of SSM demonstrated similar radiographic and HRQOL score improvements for patients in both groups. Evaluation of SSM should extend beyond measuring SVA. Among patients with concordant pain and disability, PI-LL mismatch must be evaluated for SSM patients and can be considered a primary indication for surgery.

Prevalence and type of cervical deformity among 470 adults with thoracolumbar deformity

STUDY DESIGN

Multicenter, prospective, consecutive case series.

OBJECTIVE

To assess prevalence and type of cervical deformity among adults with thoracolumbar (TL) deformity and to assess for associations between cervical deformities and different types of TL deformities.

SUMMARY OF BACKGROUND DATA

Cervical deformity can present concomitantly with TL deformity and have implications for the management of TL deformity.

METHODS

Multicenter, prospective, consecutive series of adult (age >18 yr) patients with TL deformity. Parameters included pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), C2-C7 sagittal vertical axis (C2-C7SVA), C7-S1SVA, and C2-C7 lordosis. Cervical deformity was defined as cervical lordosis more than 0° (cervical kyphosis [CK]) or C2-C7SVA more than 4 cm (cervical positive sagittal malalignment [CPSM]). Patients were stratified by the Scoliosis Research Society-Schwab classification of adult TL deformity, including curve type (N = sagittal deformity, T = thoracic scoliosis, L = lumbar scoliosis, and D = T + L scoliosis) and modifier grades: PT (0: <20°, +: 20°-30°, ++: >30°), C7-S1SVA (0: <4 cm, +: 4-9.5 cm, ++: >9.5 cm), and PI-LL mismatch (0: <10°, +: 10-20°, ++: >20°).

RESULTS

A total of 470 patients met criteria (mean age = 52 yr). Mean cervical lordosis and C2-C7SVA were -8° and 3.2 cm, respectively. CK and CPSM prevalence were 31% and 29%, respectively, and prevalence of CK and/or CPSM was 53%. CK prevalence differed by curve type (N = 15%, L = 27%, D = 37%, T = 49%; P < 0.001); CPSM prevalence did not differ by curve type (P = 0.19). Higher PT grades had lower CK prevalence (0 = 40%, += 27%, ++= 15%; P < 0.001) but greater CPSM prevalence (0 = 23%, += 28%, ++= 45%; P = 0.001). Similarly, higher SVA grades had lower CK prevalence (0 = 40%, += 23%, ++= 11%; P < 0.001) but greater CPSM prevalence (0 = 24%, += 24%, ++= 48%; P < 0.001). Higher PI-LL grades had lower CK prevalence (0 = 35%, += 31%, ++= 22%; P = 0.034) but no CPSM association (P = 0.46).

CONCLUSION

Cervical deformity is highly prevalent (53%) in adult TL deformity. C7-S1SVA, PT, and PI-LL modifiers are associated with cervical deformity prevalence. These findings suggest that TL deformity evaluation should include assessment for concomitant cervical deformity and that further study is warranted to define their potential clinical impact.

LEVEL OF EVIDENCE

3.

T1 pelvic angle (TPA) effectively evaluates sagittal deformity and assesses radiographical surgical outcomes longitudinally

STUDY DESIGN

Retrospective review of a multicenter database of consecutive patients undergoing 3-column osteotomy for treatment of adult spinal deformity (ASD).

OBJECTIVE

To rigorously develop a T1 pelvic angle (TPA) categorization paradigm and use it to assess the surgical management of patients with ASD.

SUMMARY OF BACKGROUND DATA

TPA, the angle between the hips-T1 line and hips-S1 endplate line, is a novel spinopelvic parameter that assesses the combined effect of a loss of lordosis on trunk inclination and pelvic retroversion.

METHODS

A prospective, multicenter database of consecutive patients with ASD was queried to identify the severe deformity threshold and meaningful change values for TPA by correlation with Oswestry Disability Index. A separate multicenter, consecutive, retrospective database of patients with ASD treated with single lumbar 3-column osteotomy was then analyzed at baseline, 3-month, and 1-year follow-up. Subjects were classified into well-aligned or poorly aligned groups at 3 months on the basis of TPA. Patients "deteriorated" if they lost more than 1 meaningful change in TPA between 3 months and 1 year and had TPA more than deformity threshold at 1 year.

RESULTS

The severe deformity threshold for TPA was 20° (Oswestry Disability Index > 40) and the meaningful change was 4.1° (Oswestry Disability Index change = 15). Review of the 3-column osteotomy database identified 179 patients with preoperative severe deformity; 63 were well-aligned (TPA < 15.9°) and 73 were poorly aligned (TPA > 20°) at 3-month follow-up. This newly developed TPA categorization mechanism grouped patients in a manner comparable with the Scoliosis Research Society-Schwab Classification. Subjects who were well-aligned at 3 months had less severe baseline deformity, but received more correction, than poorly aligned subjects. Four well-aligned patients and 13 poorly aligned patients deteriorated between 3 months and 1 year after surgery.

CONCLUSION

TPA accounts for sagittal vertical axis and pelvic tilt and shows great promise as a classification tool. Longitudinal analysis demonstrated undercorrection among patients with more severe preoperative deformity. We propose a surgical target of 10° for TPA.

LEVEL OF EVIDENCE

4.

Pelvic retroversion is the key protective mechanism of L4-5 degenerative spondylolisthesis

PURPOSE

To explore the role of spinopelvic sagittal alignment in the pathological mechanism of degenerative spondlylolisthesis (DS) development.

METHOD

A total of 52 asymptomatic volunteers, 32 single segment L4-5 DS and 29 lumbar spinal stenosis (LSS) without spondylolisthesis patients were enrolled. All subjects had standard lumbar spine X-ray films with standard position along with lumbar spine magnetic resonance image. Comparative analysis of sagittal parameters and disc degeneration grades among asymptomatic volunteers and patients with the two disorders were performed.

RESULTS

Compared to normal population (NP) and LSS, DS showed significantly greater pelvic incidence (PI), sacral slope (SS) and lumbar lordosis (LL), while LSS showed significantly smaller PT and PT/SS. DS showed significantly greater L5 slope than NP and LSS. In both Great-PI group and Small-PI group, all above differences between DS and LSS remained. LSS showed significantly higher degenerative grade of each adjacent disc than DS. Population with adjacent segment degeneration showed higher incidence of pelvic retroversion (PT/SS ≥1), and LSS showed greater proportion of adjacent segment degeneration than DS.

CONCLUSIONS

Lumbar spine morphology of great LL determined by great PI is a risk factor of L4-5 DS. L5 slope is a parameter that can be used to predict the risk of L4-5 DS. Pelvic retroversion is the key protective mechanism from DS. Adjacent segment degeneration is a driving factor of pelvic retroversion for compensation of lumbar sagittal malalignment.

Maintenance of radiographic correction at 2 years following lumbar pedicle subtraction osteotomy is superior with upper thoracic compared with thoracolumbar junction upper instrumented vertebra

PURPOSE

The goal of this study was to characterize the spino-pelvic realignment and the maintenance of that realignment by the upper-most instrumented vertebra (UIV) for adult deformity spinal (ASD) patients treated with lumbar pedicle subtraction osteotomy (PSO).

METHODS

ASD patients were divided by UIV, classified as upper thoracic (UT: T1-T6) or Thoracolumbar (TL: T9-L1). Complications were recorded and radiographic parameters included thoracic kyphosis (TK, T2-T12), lumbar lordosis (LL, L1-S1), sagittal vertical axis (SVA), pelvic tilt, and the mismatch between pelvic incidence and LL. Patients were also classified by the Scoliosis Research Society (SRS)-Schwab modifier grades. Changes in radiographic parameters and SRS-Schwab grades were evaluated between the two groups. Additional analyses were performed on patients with pre-operative SVA ≥ 15 cm.

RESULTS

165 patients were included (UT: 81 and TL: 84); 124 women, 41 men, with average age 59.9 ± 11.1 years (range 25-81). UT had a lower percentage of patients above the radiographic thresholds for disability than TL. UT had a significantly higher percentage of patients that improved in SRS-Schwab global alignment grade than the TL group at 2 years. Within the patients with pre-operative SVA ≥ 15 cm, TL developed significantly increased SVA and had a significantly higher percentage of patients above the SVA threshold at 3 months, and 1 and 2 years than UT.

CONCLUSIONS

Patients undergoing a single-level PSO for ASD who have fixation extending to the UT region (T1-T6) are more likely to maintain sagittal spino-pelvic alignment, lower overall revision rates and revision rate for proximal junctional kyphosis than those with fixation terminating in the TL region (T9-L1).

Radiographic Outcomes of Adult Spinal Deformity Correction: A Critical Analysis of Variability and Failures Across Deformity Patterns

STUDY DESIGN

Multicenter, prospective, consecutive, surgical case series from the International Spine Study Group.

OBJECTIVES

To evaluate the effectiveness of surgical treatment in restoring spinopelvic (SP) alignment.

SUMMARY OF BACKGROUND DATA

Pain and disability in the setting of adult spinal deformity have been correlated with global coronal alignment (GCA), sagittal vertical axis (SVA), pelvic incidence/lumbar lordosis mismatch (PI-LL), and pelvic tilt (PT). One of the main goals of surgery for adult spinal deformity is to correct these parameters to restore harmonious SP alignment.

METHODS

Inclusion criteria were operative patients (age greater than 18 years) with baseline (BL) and 1-year full-length X-rays. Thoracic and thoracolumbar Cobb angle and previous mentioned parameters were calculated. Each parameter at BL and 1 year was categorized as either pathological or normal. Pathologic limits were: Cobb greater than 30°, GCA greater than 40 mm, SVA greater than 40 mm, PI-LL greater than 10°, and PT greater than 20°. According to thresholds, corrected or worsened alignment groups of patients were identified and overall radiographic effectiveness of procedure was evaluated by combining the results from the coronal and sagittal planes.

RESULTS

A total of 161 patients (age, 55 ± 15 years) were included. At BL, 80% of patients had a Cobb angle greater than 30°, 25% had a GCA greater than 40 mm, and 42% to 58% had a pathological sagittal parameter of PI-LL, SVA, and/or PT. Sagittal deformity was corrected in about 50% of cases for patients with pathological SVA or PI-LL, whereas PT was most commonly worsened (24%) and least often corrected (24%). Only 23% of patients experienced complete radiographic correction of the deformity.

CONCLUSIONS

The frequency of inadequate SP correction was high. Pelvic tilt was the parameter least likely to be well corrected. The high rate of SP alignment failure emphasizes the need for better preoperative planning and intraoperative imaging.

Clinical improvement through nonoperative treatment of adult spinal deformity: who is likely to benefit?

Object

The goal of this study was to determine the outcome and risk factors in patients with adult spinal deformity (ASD) who elected to receive nonoperative care.

Methods

In this retrospective study the authors reviewed a nonoperative branch of the International Spine Study Group database, derived from 10 sites across the US. Specific inclusion criteria included nonoperative treatment for ASD and the availability of Scoliosis Research Society (SRS)-22 scores and radiographic data at baseline (BL) and at 1-year (1Y) follow-up. Health-related quality of life measures were assessed using the SRS-22 and radiographic data. Changes in SRS-22 scores were evaluated by domain and expressed in number of minimum clinically important differences (MCIDs) gained or lost; BL and 1Y scores were also compared with age- and sex-matched normative references.

Results

One hundred eighty-nine patients (mean age 53 years, 86% female) met inclusion criteria. Pain was the domain with the largest offset for 43% of patients, followed by the Appearance (23%), Activity (18%), and Mental (15%) domains. On average, patients improved 0.3 MCID in Pain over 1Y, without changes in Activity or Appearance. Baseline scores significantly impacted 1Y outcomes, with up to 85% of patients in the mildest category of deformity being classified as < 1 MCID of normative reference at 1Y, versus 0% of patients with the most severe initial deformity. Baseline radiographic parameters did not correlate with outcome.

Conclusions

Patients who received nonoperative care are significantly more disabled than age- and sex-matched normative references. The likelihood for a patient to reach SRS scores similar to the normative reference at 1Y decreases with increased BL disability. Nonoperative treatment is a viable option for certain patients with ASD, and up to 24% of patients demonstrated significant improvement over 1Y with nonoperative care.