Sagittal spino-pelvic alignment after surgical reduction for pediatric high-grade developmental spondylolisthesis

English Keywords:Spondylolisthesis  Reduction  Sagittal alignment  Surgery  Child

English Abstract:

  【Abstract】 Objectives: To determine the effect of surgical reduction for pediatric L5 high-grade developmental spondylolisthesis on the sagittal spino-pelvic alignment. Methods: Thirteen children(two boys and eleven girls) with L5 high-grade developmental spondylolisthesis were retrospectively evaluated in this study, all cases underwent the process of decompression, reduction, internal fixation and fusion. Radiological assessment of spino-pelvic sagittal alignment was carried out. The average age at surgery was 11.5±2.4 years(range 7-15 years). The differences of radiological parameters[slip degree, lumbar lordosis(LL), Boxall′s slip angle(BSA), Spinal Deformity Study Group dysplastic lumbosacral angle(SDSG-dys LSA), pelvic incidence(PI), pelvic tilt(PT) and sacral slope(SS)] between preoperation and final follow-up were compared by the paired sample t test. Results: The average follow-up time was 20.6±21.9 months(range, 3-64 months). Spondylolisthesis decreased from the average (76.01±16.64)% at preoperation to (17.57±16.64)% at final follow-up(P<0.01), with the improvement rate of (58.44±16.31)%, four children with grade Ⅲ spondylolisthesis got completely reduction. Sacral dome osteotomy was performed in 11 patients, with the correction rate of (30.16±14.54)%. All patients showed statistically significant changes of above parameters at final follow-up compared with preoperative ones(P<0.05). LL decreased from 74.75°±18.11° to 57.77°±14.83°, BSA from 48.98°±16.01° to 19.56°±18.70°, SDSG-dys LSA from 19.78°±20.19° to -1.72°±19.04°, while SS increased from 28.68°±23.21° to 41.13°±15.67°. PI increased from 65.64°±19.88° to 73.20°±18.85° and PT decreased from 36.88°±11.68° to 32.03°±11.76°, which showed no statistically significant changes at final follow-up compared with preoperative ones(P>0.05). Sagittal vertical axis(SVA) decreased compared with preoperative ones. Improvements of pelvic sagittal alignment after surgical reduction in the retroverted pelvis group were more obvious than those in the balanced pelvis group, 20% of the cases shifted from retroverted pelvis to balanced pelvis at final follow-up. Conclusions: Surgical reduction for pediatric L5 high-grade developmental spondylolisthesis can improve the spino-pelvic and sacro-pelvic sagittal alignment, and correct the lumbosacral kyphosis.