The pelvic balance after surgical treatment for pediatric SDSG 5/6 developmental spondylolisthesis

English Keywords:Lumbar spondylolisthesis  Dysplasia  Pelvic parameters  Unbalanced pelvis  Children

English Abstract:

  【Abstract】 Objectives: To investigate the effect of surgical reduction and reconstruction of lumbosacral lordosis on the improvement of pelvic balance in children with high-grade developmental spondylolisthesis of type 5 and 6 according to Spinal Deformity Study Group(SDSG) classification. Methods: 23 children with high-grade developmental spondylolisthesis treated by operation from February 2015 to February 2019 were analyzed retrospectively. There were 2 males and 21 females, aged 5.3 to 13.8 years(9.6±2.4 years). All patients with retroverted pelvis before operation were classified into type 5 and 6 according to SDSG classification. All patients underwent decompression, reduction, lumbosacral kyphosis correction and internal fixation. The related parameters of sagittal plane of spine and pelvis were measured before operation and at one year follow-up, including pelvic incidence(PI), pelvic tilt(PT), sacral slope(SS), L5 slope(L5S), lumbar lordosis(LL), slip percentage(SP), SDSG dysplastic lumbosacral angle(SDSG-dysLSA), Boxall′s slip angle(BSA), Dubousset′s lumbosacral angle(Dub-LSA), and kyphotic Cobb angle(k-Cobb). All patients were divided into two groups according to postoperative pelvic rotation, group balanced pelvis and group unbalanced pelvis. Comparison of lumbosacral kyphosis, slippage reduction rate and proximal anchoring level was made between two groups. Results: The patients were followed up for 26±11 months(13-48 months). There was no significant change in PI(P>0.05). SS and Dub-LSA increased significantly(P<0.05). PT, L5S, LL, SP, SDSG dys-LSA and BSA decreased significantly(P<0.05). The k-Cobb was improved from 11.6°±12.8° to -11.5°±16.3°. The reduction rate of spondylolisthesis was (85.5±16.4)%. Of the 23 patients, 5(22%) had pelvic improvement to balanced type. Group of balanced pelvis had a higher reduction rate than group of unbalanced pelvis(90.9% vs. 76.2%, P<0.05). There was no significant difference on lumbosacral kyphosis and proximal anchoring level between two groups. Conclusions: Surgical reduction of spondylolisthesis and reconstruction of lumbosacral lordosis can improve the sagittal balance of spine-pelvis in children with dysplastic severe spondylolisthesis. 22% of the patients could be improved from unbalanced pelvis to balanced pelvis.