Two-year clinical and radiological outcomes of minimally invasive surgery for severe adult degenerative scoliosis

Abstract

Objectives: To evaluate the efficacy of restoring the balance in the coronal and sagittal planes and to evaluate clinical outcomes in the treatment of severe adult degenerative scoliosis patients using staged lateral lumbar interbody fusion (LLIF) and percutaneous transpedicle screw fixation (pTSF). Methods: A retrospective analysis was made on 13 patients with severe adult degenerative scoliosis treated with staged surgery in Ruijin Hospital between May, 2014 and July, 2015. The operation data were collected, including operation time, estimated blood loss, and complications. Preoperative and postoperative standing anteroposterior and lateral lumbar radiographs were obtained by EOS image system in all patients for measurement of sagittal and coronal plane alignment. All patients were available for at least 24 months of following-up (18-32 months). Paired sample t test was used to compare the parameters of each group pre- and post-operation. Results: All of the 13 patients received LLIF with staged transpedicle screw fixation. Mean operation time was (231±48) minutes and (155±33) minutes for two-stage surgery. Mean blood loss was (253±80) ml during one-stage LLIF surgery and (326±99) ml during two-stage pTSF surgery. The interval between two surgical procedures was from 7 to 42 days (mean 14 days). In the coronal plane, the mean Cobb angle of curves was 43.1°±7.3° preoperatively, and it was 11.4°±4.0°after one-stage LLIF (t=10.16, P<0.001) and 5.5°±1.9° after two-stage pTSF (t=6.14, P<0.001). In the sagittal plane, lumbar lordosis (LL) changed after each procedure was as follows: LLIF from 16.8°±8.4° to 30.1°±6.8° (t=5.21, P<0.001) and PSF to 37.1°±4.0° (t=5.04, P<0.001). Sagittal vertical axis (SVA) was reduced from (10.5±2.4) cm to (5.3±2.1) cm after one-stage LLIF (t=8.52, P<0.001) and to (3.1±1.5) cm after two-stage pTSF (t=5.51, P<0.001). In the spino-pelvic parameter, pelvic incidence(PI)-LL mismatch decreased from 33.6°±9.6° to 17.8°±4.5° (t=5.31, P<0.001) after LLIF and to 9.9°±3.7° after pTSF (t=4.68, P<0.001). The visual analogue scale (VAS) of low back pain and leg pain and the Oswestry dability Index (ODI) improved significantly at the last follow-up (t=10.42, 8.94, 19.20, all P<0.01). Conclusions: LLIF significantly improves segmental and coronal plane alignment in patients with degenerative lumbar scoliosis, and these patients can be effectively corrected by staged minimally invasive surgery.