Clinical outcomes of posterior hemivertebra resection combined with unilateral single S2 alar-iliac screw fixation in the treatment of pediatric lumbosacral hemivertebra

English Keywords:Scoliosis  Hemivertebra  Bone screws  Pelvic fixation  S2 alar-iliac screw

English Abstract:

  【Abstract】 Objectives: To investigate the short-term clinical outcomes and complications of posterior hemivertebra resection and unilateral single S2 alar-iliac(S2AI) screw fixation in treating pediatric lumbosacral hemivertebra. Methods: The data of 16 patients undergone posterior hemivertebra resection and unilateral single S2AI screw fixation from January 2017 to December 2021 were retrospective reviewed. There were 6 males and 10 females, aged 10.6±3.7 years(6-18 years). All 16 patients(hemivertebra located between L5 and S1) underwent vertebral column resection(VCR) of lumbosacral hemivertebra and unilateral single S2AI screw pelvic fixation. The main imaging parameters including lumbosacral curve Cobb angle, compensatory curve Cobb angle, regional kyphosis(RK), coronal balance distance(CBD), and L5 tilt angle. The Scoliosis Research Society(SRS)-22 questionnaires and Oswestry disability index(ODI) were utilized to evaluate the patient-reported outcomes before and at final follow-up. Complications were also recorded. Result: The follow-up period was 18.7±3.6 months(12-26 months). The lumbosacral curve Cobb angle was 32.3°±8.7° before operation, which was improved to 8.6°±3.8° after operation, with significant difference(P<0.001), and 9.0°±3.7° at final follow-up, with no statistical difference comparing with the postoperative value(P=0.110) and no significant loss of correction during follow-up. The pre-operative, post-operative and final follow-up compensatory curve Cobb angles were 42.5°±9.5°, 18.2°±8.0°(vs preoperation, P＜0.001) and 17.9°±8.1°(vs postoperatin, P=0.120), with no significant loss of correction during follow-up. The pre-operative, post-operative and final follow-up L5 tilt angles were 17.5°±5.7°, 6.5°±3.7°(vs preoperation, P＜0.001) and 6.7°±3.8°(vs postoperatin, P=0.103), with no significant loss of correction during follow-up. The pre-operative, post-operative and final follow-up CBDs were 41.4±10.2mm, 13.1±6.0mm(vs preoperation, P＜0.001) and 14.0±6.5mm(vs postoperatin, P=0.084), well maintained during follow-up. RK angle was found with no statistical difference between preoperation, postoperation and final follow-up. At final follow-up, the SRS-22 score and ODI were significantly improved compared with those pre-operation(P＜0.001). In all 16 patients, there were no changes or losses in somatosensory evoked potential(SEP) and motor evoked potential(MEP) signals during the operation. One patient had S2AI screw breakage and underwent revision; Two patients suffered deep infection, and recovered at 4 weeks after debridement surgery. Conclusions: Posterior hemivertebra resection combined with unilateral single S2AI screw fixation can obtain satisfying correction in the treatment of pediatric lumbosacral hemivertebra, especially in the correction of coronal imbalance, which can be well maintained during short-term follow-up.