Surgical strategy and clinical outcomes in degenerative lumbar scoliosis with type C coronal imbalance

Objective To illustrate the surgical strategy of sequential correction in degenerative lumbar scoliosis (DLS) with type C coronal imbalance, and to evaluate the clinical outcomes and advances of sequential correction technique. Methods Twelve patients (2 males and 10 females) applying sequential correction technique from January 2015 to August 2017 were retrospectively reviewed. The ages of the cohort ranged 48-74 years and the average value was 52.3±8.4 years. The sequential correction technique was mainly applied in 3 steps: correction of local kyphoscoliosis with satellite rod on convex side of lumbar spine; correction of lumbosacral curve with L 4-S1 Intervertebral fusion and satellite rod on convex side of lumbosacral spine; correction of global deformity with bilateral long rods. The coronal parameters including Cobb angle and distance between C7 plumb line and center sacral vertical line (C7PL-CSVL), and the sagittal parameters including global kyphosis (GK) and sagittal vertical axis (SVA) were assessed at pre-operation, post-operationand last follow-up. The quality of life was evaluated using SF-36 questionnaire, and paired t test was used for the statistical analysis. Results The average follow-up period was 16.7±4.8 months. The Cobb angles at pre-operation and post-operation were 59.6°±18.7° and 25.6°±12.4° (t=3.705, P<0.001), respectively. At last follow-up, the average Cobb angle was 27.5°±13.0°, and there was no significant loss of correction (t=0.366, P=0.718). Post-operative C7PL-CSVL changed from 48.5±17.2 mm to 9.7±4.3 mm (t=5.842, P<0.001), of which the average value was 10.1±4.5 mm at last follow-up (t=0.223, P=0.826). At post-operation, 11 patients were with type A coronal imbalance, and 1 patient was still with type C coronal imbalance. The scores of bodily pain, general health, and social functioning were 8.4±1.9, 78.1±9.4 and 76.7±8.4 at pre-operation, 10.2±2.0 (t=2.260, P=0.034) , 89.5±7.6 (t=3.267, P=0.004) and 84.5±9.3 (t=2.156, P=0.042) at post-operation. In addition, there was no implant-related complications during follow-up. Conclusion The sequential correction technique could be well used in adult degenerative lumbar scoliosis patients with type C coronal imbalance, which can simplify the surgical procedure, decrease the rates of post-operative coronal imbalance, and obtain rigid internal fixation. Key words: Adult; Lumbar vertebrae; Intervertebral disc degeneration; Scoliosis; Spinal fusion