Short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type VI adult degenerative scoliosis.

BACKGROUND: The effect of short-segment decompression/fusion versus long-segment decompression/fusion and osteotomy for Lenke-Silva type VI adult degenerative scoliosis (ADS) has not been clarified. This study aimed to compare the clinical and radiographic results of short-segment fusion vs. long-segment fusion and osteotomy for patients with Lenke-Silva type VI ADS. METHODS: Data of 28 patients who underwent spinal surgery for ADS from January 2012 to January 2014 in the General Hospital of Northern Theater Command were reviewed. Of the 28 patients, 12 received long-segment fusion and osteotomy and 16 received short-segment fusion. Radiographic imaging parameters and clinical outcomes, including the sagittal vertical axis (SVA), lumbar lordosis (LL) angle, pelvic tilt (PT), sacral slope (SS), the visual analog scale (VAS), Japanese Orthopedic Association (JOA), Oswestry disability index (ODI), and lumbar stiffness disability index (LSDI) scores, were recorded. The difference between groups was compared using the dependent t test or Chi-squared test. RESULTS: The Cobb and LL angles and SVA improved in both groups; however, PT and SS angles did not improve following short fusion. There were significant differences in the post-operative SVA (26.8 ±â€Š5.4 mm vs. 47.5 ±â€Š7.6 mm, t = -8.066, P < 0.001), PT (14.7 ±â€Š1.8° vs. 29.1 ±â€Š3.4°, t = -13.277, P < 0.001), and SS (39.8 ±â€Š7.2° vs. 26.1 ±â€Š3.3°, t = 6.175, P < 0.001) between the long and short fusion groups. All patients had improved ODI, JOA, and VAS scores post-operatively (all P < 0.001), with no significant difference between the groups (all P > 0.05). The post-operative LSDI score was 3.5 ±â€Š0.5 in the long fusion group, which was significantly higher than that of the short fusion group (1.4 ±â€Š0.7; P < 0.001). CONCLUSIONS: The clinical outcomes of patients with Lenke-Silva type VI ADS who underwent short-segment decompression/fusion were comparable to those of patients who underwent long-segment decompression/fusion and osteotomy despite poor correction of sagittal imbalance. Moreover, short-segment decompression/fusion showed a short operation time and reduced surgical trauma.

Optimal Pelvic Incidence Minus Lumbar Lordosis Mismatch after Long Posterior Instrumentation and Fusion for Adult Degenerative Scoliosis.

OBJECTIVE: To evaluate the influence of Scoliosis Research Society (SRS)-Schwab sagittal modifiers of pelvic incidence minus lumbar lordosis mismatch (PI-LL) on clinical outcomes for adult degenerative scoliosis (ADS) after long posterior instrumentation and fusion. METHODS: This was a single-institute, retrospective study. From 2012 to 2014, 44 patients with ADS who underwent posterior instrumentation and fusion treatment were reviewed. Radiological evaluations were investigated by standing whole spine (posteroanterior and lateral views) X-ray and all radiological measurements, including Cobb's angle, LL, PI, and the grading of vertebral rotation, were performed by two experienced surgeons who were blind to the operations. The patients were divided into three groups based on postoperative PI-LL and the classification of the SRS-Schwab: 0 grade PI-LL (<10°, n = 13); + grade PI-LL (10°-20°, n = 19); and ++ grade PI-LL (>20°, n = 12). The clinical outcomes were assessed according to Japanese Orthopaedic Association (JOA) score, Oswestry Disability Index (ODI), Visual Analog Scale (VAS), Lumbar Stiffness Disability Index (LSDI), and complications. Other characteristic data of patients were also collected, including intraoperative blood loss, operative time, length of hospital stay, complications, number of fusion levels, and number of decompressions. RESULTS: The mean operative time, blood loss, and hospital stay were 284.5 ± 30.2 min, 1040.5 ± 1207.6 mL, and 14.5 ± 1.9 day. At the last follow-up (2.6 ± 0.6 years), the radiological and functional parameters, except the grading of vertebral rotation, were all significantly improved in comparison with preoperative results (P < 0.05), but it was obvious that an ideal PI-LL (≤10°) was not achieved in some patients. Significant differences were only observed among the three groups in the ODI and LSDI. Patients with + grade PI-LL seemed to have the best surgical outcome compared to those with 0 and ++ grade PI-LL, with the lowest ODI score (+ grade vs 0 grade, 17.3 ± 4.9 vs 26.0 ± 5.4; + grade vs ++ grade, 17.3 ± 4.9 vs 32.4 ± 7.3; P < 0.05) and lower LSDI (+ grade vs 0 grade, 1.6 ± 1.0 vs 3.5 ± 0.5, P < 0.05; + grade vs ++ grade, 1.6 ± 1.0 vs 0.6 ± 0.5, P > 0.05). A Pearson correlation analysis further demonstrated that LSDI was negatively associated with PI-LL. Furthermore, the incidence rate of postoperative complications was lower in patients with + grade PI-LL (1/19, 5.26%) than that in patients with 0 (2/13, 15.4%) and ++ grade PI-LL (3/12, 25%). CONCLUSION: Our present study suggest that the ideal PI-LL may be between 10° and 20° in ADS patients after long posterior instrumentation and fusion.