Long-Segment Posterior Instrumentation and Fusion with Freeze-Dried Allograft in Congenital Scoliosis

Abstract

Objective: The aim of this study was to evaluate the effectiveness of long-segment posterior instrumentation and allograft application in obtaining fusion in congenital scoliosis. Methods: Twenty-one patients with congenital scoliosis who were treated with long-segment posterior instrumentation (>6 levels) and freeze-dried allograft and followed up for more than 24 months were reviewed. Six patients were excluded from the study due to anterior procedures. Fifteen patients with congenital scoliosis (13 females, 2 males; mean age: 12.2 +/- 3,rears, range: 7-17 years) were retrospectively reviewed. Mean follow-up time was 30.9 +/- 9.4 (range: 24 to 48) months. Six patients had laminectomy either due to previous posterior surgeries or to address intraspinal pathologies during the posterior fusion procedure. Preoperative, postoperative and final follow-up anteroposterior and lateral spine X-rays were reviewed. Fusion was graded according to the classification reported by Bridwell et al. Results: Two patients were graded as 'no fusion' (pseudarthrosis), four patients as 'probably fused', and nine patients as 'definitely fused'. The major curve was corrected from an average of 68 +/- 18.6 to 39.3 +/- 12.2 degrees (p<0.001). Mean correction lost in the major curve was an average of 4.5 +/- 5.2 degrees in the latest follow-up. There was significant correction in the compensatory curve (preoperative 37.9 +/- 13.2 degrees, postoperative 20.2 +/- 6.6 degrees; p=0.001). Preoperative and postoperative global thoracic kyphosis were 39.5 +/- 13.3 and 32.3 +/- 7.9 degrees, respectively (p=0.018). Preoperative and postoperative global lumbar lordosis was 36.3 +/- 7.4 and 36.1 +/- 8.9 degrees, respectively (p=0.883). Successful fusion was detected in %86.7 of patients in the final follow-up. Conclusion: The usage of allograft alone to achieve fusion increases the rates of pseudarthrosis while additional anterior procedure decreases the pseudarthrosis rate in patients with congenital scoliosis that require long-segment posterior instrumentation. Further studies should be performed to assess the efficacy of the usage of polysegment pedicle screw instrumentation