Comparison of Scheuermann kyphosis correction by posterior-only thoracic pedicle screw fixation versus combined anterior/posterior fusion

Study Design. Retrospective comparison review. Objective. Compare posterior-only treatment results with segmental thoracic pedicle screw constructs versus combined posterior fusion in patients with Scheuermann kyphosis. Summary of Background Data. Traditionally, operative Scheuermann kyphosis has been treated with combined anterior/posterior spinal fusion, with the anterior portion being performed via an open thoracotomy or a video- assisted thoracoscopic approach. Methods. There were 18 patients with Scheuermann kyphosis who underwent a posterior- only thoracic pedicle screw (P/TPS) fusion and 21 who underwent an anterior/posterior fusion who were followed for a 2- year minimum. The 2 groups were well matched according to average age (anterior/posterior fusion 18.0 degrees and P/TPS 17.3 degrees; P = 0.60), maximum preoperative kyphosis (anterior/ posterior fusion 89.1 degrees and P/TPS 84.4 degrees; P = 0.21), flexibility index (anterior/posterior fusion 0.408 degrees and P/TPS 0.407 degrees; P > 0.99), and posterior fusion levels (anterior/posterior fusion 12.1 degrees and P/ PS 12.2 degrees; P = 0.95). Of 21 patients with anterior/ posterior fusions, zero versus 12 of 18 (67%) patients in the P/TPS group underwent apical Smith- Petersen osteotomies. Fixation in the anterior/posterior fusion group was achieved with hybrid hook/screw constructs. Posterior fixation in the P/TPS group was performed using segmental thoracic pedicle screw constructs. Both groups had posterior iliac bone autografting. Operating time and blood loss were noted, and radiographs were evaluated before surgery, after surgery, and at final follow- up. At final follow up, Scoliosis Research Society-30 questionnaire data and complications were recorded. Results. At surgery, operating time and blood loss were significantly less in the P/TPS group (P = 0.009 and P = 0.05, respectively). The mean residual kyphosis of the P/ TPS group averaged 38.2 degrees after surgery and 40.4 degrees at final follow-up versus anterior/posterior fusion group (51.9 degrees and 58.0 degrees, P < 0.001 and P = 0.001, respectively). Even without an anterior release, kyphosis correction in the P/TPS group averaged 54.2% after surgery and 51.8% at final follow-up versus the anterior/posterior fusion group (41.2% and 38.5%, P < 0.001 and P = 0.001, respectively). Scoliosis Research Society-30 outcome scores at final follow-up were comparable between the 2 groups (P/TPS = 120 and anterior/posterior fusion = 128; P = 0.14). The anterior posterior fusion group had 8/21 (38%) patients with complications, including paraplegia in 1, proximal junctional kyphosis in 1, proximal hook pullout in 1, and infection in 2. The P/TPS group had no complications (P = 0.003). Conclusions. With less operating time and intraoperative blood loss, posterior- only Scheuermann kyphosis treatment with thoracic pedicle screws achieved and maintained better correction, and had significantly less complications than with circumferential fusion.