Degenerative Lumbar Scoliosis

Correlations between spinopelvic parameters and health-related quality of life in degenerative lumbar scoliosis patients before and after long -level fusion surgery

BACKGROUND

For degenerative lumbar scoliosis (DLS), prior studies mainly focused on the preoperative relationship between spinopelvic parameters and health-related quality of life (HRQoL), lacking an exhaustive evaluation of the postoperative situation. Therefore, the postoperative parameters most closely bonded with clinical outcomes has not yet been well-defined in DLS patients. The objective of this study was to comprehensively assess the correlation between radiographic parameters and HRQoL before and after surgery, and to identified the most valuable spinopelvic parameters for postoperative curative effect.

METHODS

This study retrospectively reviewed 130 consecutive patients who underwent long-level fusion with at least 1 year follow-up. Standing whole-spine radiographs and HRQoL measurements were examined preoperatively and at final follow-up. Spinopelvic parameters included thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), lumbar lordosis (LL), pelvic incidence minus lumbar lordosis (PI-LL), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), sagittal vertical axis (SVA), T1 pelvic angle (TPA), Global tilt (GT), Cobb angle (CA), apical vertebral translation (AVT) and coronal vertical axis (CVA). HRQoL was evaluated using the Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), Chinese version of Lumbar Stiffness Disability Index (C-LSDI), Japanese Orthopedic Association-29 (JOA-29), Scoliosis Research Society-22 (SRS-22),and the 36-item Short Form Health Survey (SF-36) total and subscale scores. Pearson's correlation analysis was performed to determine relationships between them.

RESULTS

The study population included 104 women and 26 men with an average age of 62.9 years. Both coronal and sagittal parameters showed significant correlations with HRQoL scores pre- and post-operatively. Among the coronal parameters, only CA showed correlations with SRS-22 subscale scores, and its correlation with Self-image scores were observed both before and after surgery. Among sagittal parameters, PT, PI-LL, LL, SVA, TPA, and GT showed significant correlations with HRQoL before surgery, including ODI, JOA-29, and SF-36 PCS. At final follow-up, except for AVT, CVA, and LL, all other sagittal parameters were significantly correlated with HRQoL.

CONCLUSIONS

HRQoL scores not only correlated with radiological parameters before surgery, but also after long-term follow-up. Besides, sagittal parameters, especially postoperative PI-LL, SVA, TPA, GT, were more closely correlated with clinical outcome measurements.

Ultrasound measurement of abdominal and low back muscle symmetry in adult degenerative lumbar scoliosis: A case-control study

BACKGROUND

Individuals with adult degenerative lumbar scoliosis (ADLS) have underlying biomechanical alterations along the trunk muscles. However, few studies have evaluated trunk muscles in ADLS.

OBJECTIVE

To quantify and evaluate the symmetry, thickness, and stiffness (shear modulus) of the abdominal and back muscles in ADLS participants.

METHODS

This was a case-control study with participants aged 60-79 years with ADLS (n = 37) and without ADLS (n = 37). Radiographic examination data were collected from the participants. Ultrasound thickness and shear modulus measurements were performed to compare differences in the rectus abdominis, external oblique, internal oblique, transversus abdominis (TrA), multifidus, erector spinae, and quadratus lumborum muscles in the supine, prone and standing positions in the ADLS (n = 37) and control groups (n = 37). Thicknesses and shear modulus were compared.

RESULTS

The absolute thickness of the TrA in ADLS group was significantly greater on the convex side than on the concave side in both the supine (2.978 ± 0.552 vs. 2.556 ± 0.513, p = 0.041) and standing positions (2.671 ± 0.475 vs. 2.054 ± 0.401, p = 0.034). The percentage changes in both sides of the shear modulus of the TrA were significantly greater in the ADLS group than in the control group for the supine position (p = 0.019), and standing position (p = 0.039).

CONCLUSIONS

Compared with those in the control group, only the absolute muscle thicknesses and percent change in the shear modulus of the TrA in the ADLS participants were more asymmetric.

Development of a Motion-Based Video Game for Postural Training: A Feasibility Study on Older Adults With Adult Degenerative Scoliosis

Forward sagittal alignment affects physical performance, is associated with pain and impacts the health-related quality of life of the elderly. Interventions that help seniors to improve sagittal balance are needed to inhibit the progression of pain and disability. A motion-sensing video game (active game) is developed in this study to monitor sitting and standing postures in real-time and facilitate the postural learning process by using optical sensors to measure body movement and a video game to provide visual feedback. Ten female subjects (mean age: 60.0 ± 5.2 years old; mean BMI: 21.4 ± 1.9) with adult degenerative scoliosis (mean major Cobb's angle: 38.1° ± 22.7°) participate in a 6-week postural training programme with three one-hour postural training sessions a week. Eleven body alignment measurements of their perceived "ideal" sitting and standing postures are obtained before and after each training session to evaluate the effectiveness of postural learning with the game. The participants learn to sit and stand with increased sagittal alignment with a raised chest and more retracted head position. The forward shift of their head and upper body is significantly reduced after each training session. Although this immediate effect only partially sustained after the 6-week program, the participants learned to adjust their shoulder and pelvis level for a better lateral alignment in standing. The proposed postural training system, which is presented as a gameplay with real-time visual feedback, can effectively help players to improve their postures. This pilot feasibility study explores the development and initial assessment of a motion-based video game designed for postural training in older adults with adult degenerative scoliosis, and demonstrates the usability and benefits of active gameplay in motor training.

Impact of preoperative clinical state on 2-year clinical outcomes following degenerative lumbar scoliosis surgery

To assess the preoperative clinical state's impact on clinical outcomes after surgery for degenerative lumbar scoliosis (DLS) based on the minimal clinically important difference (MCID). Preoperative and follow-up (FU) scores in each Scoliosis Research Society-22 (SRS-22) domain were compared with age- and sex-matched normative references. At baseline, patients were classified by differences from normative values in four groups: Worst, Severe, Poor, and Moderate. At 2 years postoperative FU, patients were divided into four groups (Worst Severe Poor Asymptomatic) based on the difference in MCID between postoperative and normal values. The changes in MCID were considered as the criterion for surgical efficacy. In addition, we calculated the classification of preoperative and FU clinical symptom severity in each domain in same patient. The distinction among curve types was also performed based on the SRS-Schwab classification. A total of 123 patients were included. During FU, patients with more severe preoperative clinical symptoms were more likely to achieve clinical changes (>1 MCID, p < 0.05), but the rate of reaching "asymptomatic" was lower (p < 0.05). Kendall's tau-b correlation analysis found that preoperative clinical severity was correlated with clinical changes category in Activity (Tau-b = 0.252; p = 0.002), Pain (Tau-b = 0.230; p = 0.005), Appearance (Tau-b = 0.307; p < 0.001), and Mental (Tau-b = 0.199; p = 0.016), and it also was correlated with FU clinical severity in Activity (Tau-b = 0.173; p = 0.023), Pain (Tau-b = 0.280; p < 0.001), and Mental (Tau-b = 0.349; p < 0.001). There was a correlation between preoperative clinical severity and FU SRS-22 score outcomes. Patients with severe preoperative clinical symptoms can experience better treatment outcomes during FU, but it is also more difficult to recover to the normal reference.

Oblique lateral interbody fusion for lumbosacral fractional curve correction in degenerative lumbar scoliosis

PURPOSE

In combined anterior-posterior adult spinal deformity surgery, the optimal combination of anterior and posterior procedures remains unclear. We aimed to demonstrate the radiological outcomes and relevant factors in oblique lateral interbody fusion (OLIF) for lumbosacral fractional curve (FC) correction combined with open posterior surgery in degenerative lumbar scoliosis (DLS).

METHODS

This study involved 42 consecutive patients with DLS who had a major curve (MC) ≥ 20° and an FC (L4 to S1) ≥ 10°, and underwent a combined anterior-posterior surgery Changes in the MC, FC, coronal balance distance, type of coronal imbalance, coronal/sagittal disc angle at L4-5 and L5-S1, L4 and L5 tilt, and sagittal parameters were examined. The associations between FC correction and demographic, surgical, and radiological factors were analysed.

RESULTS

The FC decreased from 16.9 ± 7.3° preoperatively to 6.6 ± 4.4° at the last follow-up (P < 0.001). The coronal disc angle at L4-5 and L5-S1 were, respectively, 6.8 ± 2.2° and 6.0 ± 4.1° preoperatively and decreased to 2.2 ± 2.1 and 1.2 ± 1.3° at the last follow-up (both P < 0.001). The changes in FC were greater in uppermost instrumented level > T10 (P < 0.001), and associated with the preoperative FC (r = 0.820, P < 0.001), L4 tilt (r = 0.434, P = 0.007), and L5 tilt (r = 0.462, P = 0.003).

CONCLUSION

OLIF at the FC combined with open posterior surgery is an effective combined anterior-posterior correction strategy in DLS.

Risk Factors for Distal Junctional Problems Following Long Instrumented Fusion for Degenerative Lumbar Scoliosis: Are they Related to the Paraspinal Muscles

PURPOSE

Although the incidence of distal junctional problems (DJPs) following long construct-based treatment for degenerative lumbar scoliosis (DLS) is lower, affected patients are more likely to require revision surgery when they occur. So the aim of this study is to identify risk factors associated with DJPs to avoid its occurrence by at least 1-year follow-up.

METHODS

A total of 182 DLS patients undergoing long instrumented fusion surgery (≥4 levels) between February 2011 and March 2022 were retrospectively analyzed. Patients were placed into the DJP group if a DJP occurred at the final follow-up; patients without mechanical complications were matched 1:2 according to age, sex and BMI as the control group. Patient characteristics, surgical variables, radiographic parameters, lumbar muscularity and fatty degeneration were analyzed statistically. The statistical differences in the results between the two groups (p values <0.05) and other variables selected by experts were entered into a multivariate logistic regression model, and the forwards likelihood ratio method was used to analyze the independent risk factors for DJPs.

RESULTS

Twenty-four (13.2%) patients suffered a DJP in the postoperative period and the reoperation rate was 8.8%. On univariate analysis, the lowest instrumented vertebra (LIV) CT value (p = 0.042); instrumented levels (p = 0.030); preoperative coronal vertical axis (CVA) (p = 0.046), thoracolumbar kyphosis (TLK) (p = 0.006), L4-S1 lordosis (p = 0.013), sacral slop (SS) (p = 0.030), pelvic tilt (PT) classification (p = 0.004), and sagittal vertical axis (SVA) (p = 0.021); TLK correction (p = 0.049); post-operative CVA (p = 0.029); Overall, There was no significant difference in the paraspinal muscle parameters between the two groups. On multivariate analysis, instrumented levels (OR = 1.595; p = 0.035), preoperative SVA (OR = 1.016; p = 0.022) and preoperative PT (OR = 0.873; p = 0.001) were identified as significant independent risk factors for DJP.

CONCLUSION

Longer instrumented levels, a greater preoperative SVA and a smaller PT were found to be strongly associated with the presence of DJPs in patients treated for DLS. The degeneration of the paraspinal muscles may not be related to the occurrence of DJPs. For DLS patients, the occurrence of DJP can be reduced by selecting reasonable fusion segments and evaluating the patient's sagittal balance and spino-pelvic parameters before operation.

Association of Various Spinopelvic Parameters and the Quality of Life in Those With Degenerative Lumbar Scoliosis in the Indian Population

Purpose The current study aimed to find any association between various spinopelvic parameters and the quality of life in patients with degenerative lumbar scoliosis (DLS) measured as per the Oswestry disability index (ODI) and visual analog scale (VAS) in the Indian population. Methods We included 20 DLS patients of more than 40 years with a Cobb angle of more than 10° and without any trauma, tumour, infection, or congenital scoliosis presented in our tertiary care centre in the study. The VAS and ODI were calculated for each patient. Radiological parameters were recorded for every patient, including sagittal balance, coronal balance, Cobb angle, pelvic incidence, pelvic tilt, and lumbar lordotic angle. We evaluated the results and sought any association between clinical and radiological variables for DLS. Results Patients with positive sagittal balance had significantly higher disability than those with neutral sagittal balance (p-value 0.007). Furthermore, patients with coronal imbalance had more severe pain (p-value 0.013) and disability (p-value 0.038) than those with neutral coronal balance. We also found that the ODI and VAS were not associated with any other spinopelvic parameters. Conclusion From the present study, we can conclude that in the Indian population, both positive sagittal and coronal imbalances are associated with poor functional status in patients with DLS. Therefore, while planning surgical correction for these patients, both coronal and sagittal balance are important and need to be considered.

Therapeutic Strategy of Percutaneous Transforaminal Endoscopic Decompression for Stenosis Associated With Adult Degenerative Scoliosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

To investigate the effects of percutaneous transforaminal endoscopic decompression (PTED) for lumbar stenosis associated with adult degenerative scoliosis and to analyze the correlation between preoperative radiological parameters and postoperative surgical outcomes.

METHODS

Two years of retrospective data was collected from 46 patients with lumbar stenosis associated with adult degenerative scoliosis who underwent PTED. The visual analog scale (VAS), Oswestry Disability Index, and modified MacNab criteria were used to evaluate the clinical outcomes. Multiple linear regression analysis was used to analyze the correlation between radiological parameters and surgical outcomes.

RESULTS

The mean age of the 33 female and 13 male patients was 73.5 ± 8.1 years. The mean follow-up was 27.6 ± 3.5 months (range from 24 to 36). The average coronal Cobb angle was 24.5 ± 8.2°. There were better outcomes of the VAS for leg pain and Oswestry Disability Index after surgery. Based on the MacNab criteria, excellent or good outcomes were noted in 84.78% of patients. Multiple linear regression analysis showed that Cobb angle and lateral olisthy may be the predictors for low back pain.

CONCLUSION

Transforaminal endoscopic surgery may be an effective and safe method for geriatric patients with lumbar stenosis associated with degenerative scoliosis. The predictive factors of clinical outcomes were severe Cobb angle and high degree lateral subluxation. Transforaminal endoscopic surgery may not be recommended for patients with Cobb angle larger than 30° combined with lateral subluxation.

The classification of coronal deformity based on preoperative global coronal malalignment for adult spinal deformity is questionable

Study design

Retrospective case–control radiographic study.

Objective

To identify main effects of preoperative pattern and global coronal malalignment (GCM) on postoperative coronal imbalance in degenerative lumbar scoliosis (DLS) patients and evaluate the rationality of the classification of coronal deformity based on preoperative GCM.

Summary of background data

A classification of coronal deformity based on preoperative GCM (20 mm set as the threshold of coronal imbalance) has been proposed recently, but whether it is practical is unclear.

Methods

One hundred twelve DLS patients treated with posterior instrumented fusion were reviewed. Coronal measurements included GCM and major Cobb angle. Based on relationship between C7 PL and major curve, preoperative patterns were classified into: Pattern 1(concave pattern), C7 PL shifted to the concave side of major curve; Pattern 2(convex pattern), C7 PL shifted to the convex side of major curve. Patients were separated into 4 groups (3 types): Type 0–1: GCM < 20 mm plus Pattern 1; Type 0–2: GCM < 20 mm plus Pattern 2; Type 1: GCM > 20 mm plus Pattern 1; Type 2: GCM > 20 mm plus Pattern 2. After comparison within patterns or among 4 groups, further factorial analysis was performed.

Results

Significant differences regarding postoperative GCM or coronal imbalance/balance ratio existed among 4 groups (F = 6.219, p = 0.001; x² = 22.506, p < 0.001, respectively), despite no significant difference in intra-pattern 1(concave pattern) or intra-pattern 2(convex pattern) groups. Two-way analysis of variance showed preoperative pattern exhibited significant effect on postoperative GCM or imbalance/balance ratio (F_(1,108) = 14.286, p < 0.001; F_(1,108) = 30.514, p < 0.001, respectively) while neither preoperative GCM alone nor interaction of preoperative GCM with pattern did.

Conclusion

In DLS patients, it’s the preoperative pattern other than GCM that had main effects on postoperative coronal imbalance. Classification of coronal deformity based on preoperative GCM is questionable.

Level of evidence

3

Incidence, Risk, and Outcome of Pedicle Screw Loosening in Degenerative Lumbar Scoliosis Patients Undergoing Long-Segment Fusion

STUDY DESIGN

Retrospective study.

OBJECTIVE

To investigate the incidence, risk factors, and outcomes of pedicle screw loosening in degenerative lumbar scoliosis (DLS) undergoing long-segment spinal fusion surgery.

METHODS

One hundred and thirty DLS patients who underwent long-segment fusion surgery with at least a 12-month follow-up were studied. The incidence and risk factors of screw loosening were investigated. VAS, SRS-22, and ODI scores were obtained preoperatively and at follow-up.

RESULTS

One hundred and sixty-eight of 1784 (9.4%) screws showed evidence of loosening in 71 (54.6%) patients. Three patients required revision surgery. Screw loosening rates according to vertebral insertion level were lowest instrumented vertebra (LIV): 45.4%; uppermost instrumented vertebra (UIV):17.7%; one vertebra above the LIV: 0.5%; 2 vertebrae above the LIV: 0.4%. Multiple logistic regression analysis of possible risk factors indicated that preoperative lateral subluxation ≥8 mm (odds ratio [OR]: 2.68, 95% confidence interval [CI]: 1.16-6.20), osteopenia (OR: 5.52, 95% CI: 1.64-18.56), osteoporosis (OR: 8.19, 95% CI: 2.40-27.97), fusion to sacrum (OR: 2.55, 95% CI: 1.12-5.83), postoperative TLK greater than 10° (OR: 2.63, 95% CI: 1.14-6.04) and SVA imbalance (OR: 3.44, 95% CI: 1.17-10.14) were statistically significant. No difference was noted in preoperative, follow-up, and change of VAS, ODI, and SRS-22 scores.

CONCLUSIONS

Screw loosening in DLS underwent long-segment surgery is common and tends to occur in the LIV or UIV. Lateral subluxation ≥8 mm, osteopenia, osteoporosis, fusion to the sacrum, postoperative TLK greater than 10°, and SVA imbalance were the independent influencing factors. Screw loosening can be asymptomatic, while longer-term follow-up is required.

Directionality of Lumbosacral Fractional Curve Relative to C7 Plumb Line, A Novel Index Associated with Postoperative Coronal Imbalance in Patients with Degenerative Lumbar Scoliosis

STUDY DESIGN

Retrospective case-control radiographic study.

OBJECTIVE

The aim of this study was to explore whether directionality of lumbosacral fractional curve relative to C7 plumb line (PL) affected postoperative coronal imbalance in patients with degenerative lumbar scoliosis (DLS).

SUMMARY OF BACKGROUND DATA

The spatial relationship between lumbar main curve and C7 PL was reported to have impact on postoperative coronal imbalance in DLS. Although fractional curve played more important role than lumbar main curve in DLS, the spatial relationship between fractional curve and C7 PL and their impact on the postoperative coronal balance are still unknown.

METHODS

One hundred one DLS patients treated with posterior instrumented fusion were reviewed. Coronal measurements included C7 migration, fractional curve, L4/L5 coronal tilt, major Cobb angle. Based on directionality of fractional curve (orientation of L4 coronal tilt was used to represent it) relative to C7 PL preoperatively, coronal patterns was separated into: consistency pattern, L4 coronally tilts toward C7 PL; opposition pattern, L4 coronally tilts opposite C7 PL; the distributions of these two patterns and Type A, B,C were analyzed. According to postoperative C7 migration, patients were divided into imbalanced group and balanced group.

RESULTS

Compared to balanced group, the imbalanced group had higher percentage of preoperative consistency pattern (80.6% vs. 33.8%, P < 0.001) and Type C (36.1% vs. 7.7%, P < 0.001); larger fractional curve or L4 coronal tilt pre- and postoperatively, larger L5 coronal tilt postoperatively. Logistic regression analysis showed predictors for postoperative coronal imbalance were consistency pattern (odds ratio [OR] 5.103, 95% confidence interval [CI]: 1.660-15.687, P = 0.004) and type C (OR 4.061; 95% CI: 1.056-15.618; P = 0.041).

CONCLUSION

Directionality of fractional curve relative to C7 PL was associated with postoperative coronal imbalance in DLS patients. In addition to type C, consistency pattern might be an independent risk factor for postoperative coronal imbalance.Level of Evidence: 3.

Prospective investigation of Oswestry Disability Index and short form 36 subscale scores related to sagittal and coronal parameters in patients with degenerative lumbar scoliosis

PURPOSE

This study investigated relationships of Oswestry Disability Index (ODI) and Short Form 36 (SF-36) total and subscale scores with global spinal parameters in patients with degenerative lumbar scoliosis (DLS).

METHODS

This was a prospective single-center study of 126 consecutive patients with DLS. Disability was evaluated using the ODI and SF-36 total and subscale scores. Sagittal and coronal parameters were measured. Pearson's correlation analysis was performed to determine relationships between disability and radiographic parameters.

RESULTS

The study population included 76 women and 15 men (mean age, 70.2 ± 8.4 years). Mean Cobb angle was 18.9° ± 8.0°. The ODI total score and SF-36 physical component score were only correlated with coronal parameters. ODI pain intensity, personal care, lifting, sitting, and sex life domains were only correlated with coronal parameters. The walking, standing, social life, and traveling domain scores were correlated with coronal and sagittal parameters. The SF-36 bodily pain and vitality domain scores were only correlated with coronal parameters. The SF-36 physical function domain score was correlated with both coronal and sagittal parameters. Among the clinical and radiographic parameters, the personal care score and the coronal vertical-axis had the strongest correlation (r = 0.425), although the r² value was only 0.18.

CONCLUSIONS

ODI total score and most of the subscale scores were significantly, but weakly correlated with coronal parameters. Sagittal parameters were only correlated with some of the ODI and SF-36 subscale scores. Analysis using ODI and SF-36 subscale scores may aid in understanding and treatment of disability in patients with DLS.

Degenerative lumbar scoliosis patients with proximal junctional kyphosis have lower muscularity, fatty degeneration at the lumbar area

PURPOSE

To assess the lumbar muscle conditions on the incidence of proximal junctional kyphosis (PJK) after long-level correction and instrumentation surgery for degenerative lumbar scoliosis (DLS) patients with a minimum 2-year follow-up.

METHODS

Eighty-four DLS patients undergoing long instrumented fusion surgery (≥ 5 vertebrae) were retrospectively studied. According to the occurrence of PJK at the final follow-up, patients were divided into the PJK group and the Non-PJK group. Patient characteristics, surgical variables and radiographic parameters were analyzed statistically. The lumbar muscularity (cross-sectional area of muscle-disc ratio × 100) and fatty degeneration (signal intensity of muscle-subcutaneous fat ratio × 100) were evaluated on magnetic resonance imaging .

RESULTS

The prevalence of PJK was 20.24%. Gender, age at surgery, body mass index, uppermost instrumented vertebrae level, fusions extending to the sacrum, and levels fused were not significantly different between the groups. Lower bone mineral density, smaller functional cross-sectional area (FCSA) of paraspinal extensor muscles (PSE), higher lean muscle-fat index and total muscle-fat index of PSE, greater preoperative thoracolumbar kyphosis (TLK), smaller preoperative sacral slope (SS), larger preoperative sagittal vertical axis were identified in PJK group. Logistic regression analysis showed that osteoporosis, preoperative TLK > 15°, SS > 24°, FCSA of PSE > 138.75, and total muscle-fat index of PSE > 4.08 were independently associated with PJK. The final follow-up VAS score for back pain was higher, and SRS-22 subcategories of pain, function, self-image, and total score were significantly lower in the PJK group.

CONCLUSION

Osteoporosis, lower lumbar muscularity and higher fatty degeneration, preoperative greater TLK and smaller SS were found to be strongly associated with the presence of PJK in DLS.

Compensatory Mechanism of Maintaining the Sagittal Balance in Degenerative Lumbar Scoliosis Patients with Different Pelvic Incidence

Objective

To investigate the compensatory mechanism of maintaining the sagittal balance in degenerative lumbar scoliosis patients with different pelvic incidence (PI).

Methods

This was a retrospective imaging observation study. Patients in our department with degenerative lumbar scoliosis between 2017 and 2019 were reviewed. A total of 36 patients were eligible and included in the present study. The average age of those patients was 64.22 years, including 8 men and 28 women. The coronal and sagittal parameters were measured on full‐length spine X‐ray film, including globe kyphosis (GK), lumber lordosis (LL), thoracolumbar kyphosis (TLK), thoracic kyphosis (TK), sagittal vertical axis (SVA), sagittal shift angle, Cobb angle, coronal shift angle, and vertebra. The anterior pelvic plane angle (APPA) and pelvic parameters were also measured, including the pelvic tilt (PT), the PI, and the sacral slope (SS). PI‐LL, LL‐SS, and GK‐SS were calculated. Traditional pelvic tilt was also calculated using the following formula: cPT = PI × 0.37–7. These patients were divided into two groups according to their PI values. The patients’ PI value in Group 1 was smaller than 50°. The patients’ PI value in Group 2 was equal to or larger than 50°.

Results

These patients’ SS, PT, PI, LL, TLK, TK, and GK were 28.70° ± 11.36°, 23.28° ± 6.55°, 52.00° ± 11.03°, 31.66° ± 14.12°, 12.12° ± 14.9°, 17.81° ± 13.53°, and −13.17° ± 16.27°. The sagittal shift angle, the APPA, the Cobb angle, the coronal shift angle, vertebra, PI‐LL, cPT, APPA‐4, LL‐SS, and GK‐SS were 4.38° ± 5.75°, −12.55° ± 8.83°, 30.03° ± 12.59°, 2.40° ± 2.13°, 4.08 ± 0.93, 19.86° ± 10.97°, 12.35° ± 4.55°, −8.30° ± 9.07°, 3.30° ± 8.82°, and 15.53° ± 9.83°, respectively. There was no significant difference between PT and cPT + APPA‐4 or between cPT and PT‐APPA+4. There was significant difference between PT and cPT + APPA or between cPT and PT‐APPA. This demonstrated that the APPA‐4 is reliable as degree of the pelvic sagittal retroversion. There were significant differences in SS, PI, LL, TLK, GK, APPA, PT‐APPA, PT‐APPA+4, cPT, and APPA‐4 between Group 1 and Group 2. There were no significant differences in PT, TK, sagittal shift angle, SVA, Cobb angle, coronal shift angle, vertebra number, PI‐LL, cPT + APPA, cPT + APPA‐4, LL‐SS, and GK‐SS between Group 1 and Group 2. The Pearson tests showed that PI‐LL had significant correlations with TK, LL, sagittal shift angle, SVA, and LL‐SS. There was no significant correlation between PI‐LL and Cobb angle, GK, TLK, APPA, vertebra, Coronal Shift Angle, or GK‐SS.

Conclusion

The APPA‐4 is reliable as degree of the pelvic sagittal retroversion. In degenerative lumbar scoliosis, patients with smaller PI tended to rely more on the pelvic retroversion to maintain the sagittal balance than patients with larger PI, or patients with smaller PI were likely to start up the pelvic retroversion compensatory mechanism earlier than the patients with larger PI.

Does sagittal imbalance impact the surgical outcomes of short-segment fusion for lumbar spinal stenosis associated with degenerative lumbar scoliosis?

BACKGROUND

The degenerative lumbar scoliosis (DLS) patients who mainly complained about neurogenic claudication due to spinal canal stenosis are well-indicated for short segment fusion (SSF) at the affecting levels. However, it is unclear whether we should consider global sagittal balance or not. The aim of this study was to evaluate the impact of sagittal balance on the surgical outcomes of degenerative lumbar scoliosis (DLS) patients who underwent SSF.

METHODS

We retrospectively reviewed 70 DLS patients who underwent SSF (less than 3 levels) and could be followed for at least 2 years. The PI-LL, PT, SVA, and T1 pelvic angle (TPA) were measured using standing whole spine X-rays preoperatively (PreO) and at final follow-up (FFU). Surgical outcomes were assessed with the improvement in Japanese Orthopaedic Association score (JOAs) for low back pain (LBP), and the level of LBP was measured using the visual analogue scale (LBP-VAS). We analysed the relationships between the radiographic parameters and the surgical outcomes.

RESULTS

We divided the patients into the three groups (poor/fair/good) based on the JOAs. The analysis with the Jonckheere-Terpstra trend test indicated that the following radiographic parameters had a significant trend with surgical outcomes in each group: (poor/fair/good; p value); PreO PI-LL (26/20/17°; P = 0.04), SVA (46/75/35.5 mm; P = 0.02), TPA (28/27/23°; p = 0.04), FFU PI-LL (33/25/8.5°; P = 0.004), SVA (93/90.5/32.5 mm; P = 0.001), and TPA (33/29/25°; P = 0.007). Additionally, LBP-VAS had a significant correlation between the three groups at final follow-up (P = 0.004). There were significant correlations between improvement in JOAs and PI-LL, SVA, and TPA both PreO and at FFU (P < 0.05).

CONCLUSIONS

Sagittal spinal imbalance and spinopelvic malalignment significantly impact the surgical outcomes of SSF for DLS. Preoperative evaluation of spinopelvic alignment and sagittal balance is of critical importance when SSF are performed for DLS patients.

Renal Artery Dissection in a Patient With Degenerative Scoliosis: A Rare Complication Caused by Lumbar Vertebra Osteophyte

Isolated spontaneous renal artery dissection (RAD) without known trauma is rare, and its etiology has not been determined. However, notable risk factors including hypertension, strenuous exercise, connective tissue disorders, atherosclerosis, extracorporeal shock wave lithotripsy, and cocaine abuse have been reported. To the best of our knowledge, isolated RAD caused by lumbar vertebra osteophytes in patients with degenerative lumbar scoliosis has not been reported in the literature. In this article, we present a case of RAD caused by lumbar vertebra osteophyte in a patient with degenerative scoliosis and discuss the management of the disease.

Morphometric Analysis of the Retroperitoneal Vessels With Respect to Lateral Access Surgery in Adult Scoliosis

STUDY DESIGN

Cross-sectional study reviewing 62 magnetic resonance imaging or computed tomography scans from consecutive adult patients with scoliotic spinal deformity in the thoracolumbar spine.

OBJECTIVE

To investigate the variation in anatomic position of retroperitoneal vessels in relationship to curve direction, location, magnitude, and axial rotation of curves in adult scoliosis.

SUMMARY OF BACKGROUND DATA

The minimally invasive lateral approach to the thoracolumbar spine avoids manipulation of abdominal and retroperitoneal structures and decreases risk of injury to paraspinal musculature. In adult patients with scoliosis, the varying anatomic relationship between retroperitoneal vessels and intervertebral disk spaces can increase the risk of vascular injury.

MATERIALS AND METHODS

Axial images were used to measure the anterior-posterior diameter of the inferior vertebral endplate with respect to the disk space perpendicular to the widest length of the disk. The overlap of the retroperitoneal vessels with the endplate were measured at the cephalad end vertebra, apex, and caudad end vertebra of each curve. Overlap and accessible disk space for individual disk spaces were also measured.

RESULTS

There was a significant difference in percentage overlap of the apex and cephalad vertebral endplate and inferior vena cava in right versus left-sided curves (P=0.002). Overlap between the inferior vertebral endplate and inferior vena cava at the cephalad, apex, and caudad end of the curve was significantly different between thoracolumbar and lumbar curves (P<0.05). Axial rotation significantly affected vessel overlap at multiple curve locations. There was a statistically significant difference in accessible disk space when approaching the curve from the concavity versus convexity.

CONCLUSIONS

Overlap between retroperitoneal vessels and inferior vertebral endplates at the disk level in scoliotic spines varies significantly with direction of the curvature, level of the deformity, and degree of axial rotation. There is decreased accessible disk space and increased vessel overlap on the concavity of the curve. Surgeons, as usual, will take an individualized case by case approach to avoid approach-related vascular complications, but the general relationships reported in this study can guide side of approach.