Short-segment bone-on-bone fusion of adolescent idiopathic scoliosis using Kaneda Anterior Spinal System

Abstract

Purpose of study: The objective of this study was to evaluate a new technique for treatment of idiopathic scoliosis with a single major curve using the short-segment, bone-on-bone approach and the Kaneda Anterior Spinal System (KASS). This report describes the technique and presents the results for our first 10 patients.Methods used: The short-segment bone-on-bone KASS technique was performed in 10 consecutive patients with adolescent idiopathic thoracic or thoracolumbar scoliosis. The mean age was 14.4 years (12 to 20 years), and the average follow-up was 44 months (range, 34 to 61 months). None were lost to follow-up.of findings: Preoperatively, the major curve averaged 48 degrees (38 to 55 degrees); this corrected to 11 degrees (0 to 20 degrees) postoperatively (77% correction rate). Preoperative compensatory curves measured 34 degrees (29 to 39 degrees); these spontaneously corrected to 13 degrees postoperatively (62% correction rate) as a consequence of correction of primary curve. The preoperative tilt angle was 20 degrees (14 to 28 degrees). Postoperatively the tilt angle was reduced to 6 degrees (2 to 10 degrees). The tilt angle correction was 70%. The fusion was healed and postoperative immobilization discontinued 6 to 10 weeks after the procedure. There was no loss of correction. The average number of vertebra fused using our technique was five (four discs). The average number of posterior fusion levels are proposed by King was 10. There were no implant problems, nonunions or serious peri- or postoperative complications.Relationship between findings and existing knowledge: The bone-on-bone short-segment technique permits correction of single-curve idiopathic scoliosis below 75 degrees over half the levels that have been traditionally operated on by posterior instrumentation, yet provides 77% average correction with no nonunion, no loss of correction and healing in 6 to 8 weeks.Overall significance of findings: The new short-segment, bone-on-bone approach for single major curves using the KASS instrumentation provides excellent correction over half the levels operated on by previous posterior systems with rapid fusion and with no loss of correction.Disclosures: Device or drug: Kaneda Anterior Spinal System. Status: approved.Conflict of interest: Robert Gaines, consultant speaker's bureau; and, other support from De Puy Acromed.