3:51 Single-rod instrumentation in the treatment of adolescent idiopathic scoliosis

Abstract

Purpose of study: Single-rod posterior spinal instrumentation for the treatment of adolescent idiopathic scoliosis (AIS) was briefly considered as an alternative to the traditional double-rod construct. Cited advantages include decreased incidence of infection, blood loss, operative time, cost of instrumentation and technical difficulty of the procedure. A retrospective analysis of patients with AIS treated with single-rod posterior instrumentation with segmental fixation was undertaken.Methods used: Forty-two patients were initially identified. Seventeen were excluded because of inadequate follow-up (less than 2 years). Twenty-five patients, 2 male and 23 females, were included in our study. Charts and radiographs were reviewed. All had right thoracic curve patterns. All patients underwent instrumentation and fusion by means of the standard posterior approach performed by a single surgeon (PFS). All levels except the apical vertebrae were instrumented. Distraction was performed. No patients were initially braced.of findings: The average age was 13.9 years (± 2.2 years). Months of follow-up averaged 40.5. Number of segments fused averaged 10.4. Average preoperative and postoperative curves measured 52.5 and 24 degrees, respectively. Postoperative correction averaged 28 degrees. Loss of correction at latest follow-up averaged 7 degrees. Length of surgery averaged 279 minutes. Blood loss averaged 880 cc. Hospital stay averaged 4.8 days. The total complication rate was 40% (10 of 25 patients). Rod breakage occurred in six patients (24%) with five requiring revision (20%). Two developed late infections (8%). One patient's curve decompensated requiring bracing (4%), and one patient's curve decompensated above the instrumented region requiring revision (4%). Cost analysis was performed on the first 14 patients instrumented with the Richards Scoliosis System. The average hardware cost per patient for a single-rod construct was $2,567. The average calculated cost per patient for a double-rod construct was $3,326.Relationship between findings and existing knowledge: Only a few studies have been published in recent years comparing posterior segmental single-rod constructs with traditional double-rod constructs for the treatment of AIS. These studies have generally found that single-rod constructs are prone to implant failure. Our study supports this finding. In addition, we had an infection rate comparable to those reported for most studies involving traditional double-rod constructs. Previous authors have cited a theoretical decreased risk of infection with a single-rod construct because of decreased hardware surface area, decreased dead space and decreased operative time. Our findings do not support this theoretical advantage of single-rod constructs.Overall significance of findings: Because of the high complication rate present in our study, we do not recommend a single-rod instrumentation in the treatment of AIS.Disclosures: No disclosures.Conflict of interest: No conflicts.