Scoliosis Research Society-Schwab Grade 6 Osteotomy for Severe Congenital Angular Kyphoscoliosis: An Analysis of 17 Cases With a Minimum 2-Year Follow-up

BACKGROUND: For some patients with severe congenital angular kyphoscoliosis (SCAK), 1-level vertebral column resection is insufficient and the Scoliosis Research Society (SRS)-Schwab Grade 6 osteotomy may be necessary. However, the indications and clinical outcomes of SRS-Schwab Grade 6 osteotomy in patients with SCAK have not been investigated in depth. OBJECTIVE: To investigate the middle-term radiographic and clinical outcomes, and to evaluate the safety of this high technique-demanding procedure. METHODS: Patients with SCAK undergoing SRS-Schwab Grade 6 osteotomy from 2005 to 2016 followed up at least 2 yr were retrospectively reviewed. The potential indications of SRS-Schwab Grade 6 osteotomy were analyzed. The coronal Cobb angle, segmental kyphosis (SK), deformity angular ratio (DAR), coronal balance, and sagittal vertical axis (SVA) were measured in the preoperative, postoperative, and final follow-up. The intraoperative and postoperative complications were recorded. RESULTS: A total of 17 patients with SCAK (10 M and 7F) were included, and the mean follow-up was 30.8 ± 16.4 mo. The indications of SRS-Schwab Grade 6 osteotomy were as follows: multiple "pushed-out" hemivertebrae (13, 76.5%) and multilevel anterior block (4, 23.5%). Compared with preoperation, the coronal Cobb angle, SK and SVA at postoperation were significantly improved (P < .05 for all). The mean total DAR was 33.4 ± 9.9 at preoperation. Three patients were found to have postoperative neurological deficit. Rod breakage occurred in 3 patients at 15- to 48-mo follow-up, and revision surgeries were performed. At the last follow-up, firm bony fusion was observed in all patients. CONCLUSION: The technique-demanding SRS-Schwab Grade 6 osteotomy, if well indicated, could provide satisfying correction of the SCAK deformity.