Prospective radiographic and clinical outcomes and complications of single solid rod instrumented anterior spinal fusion in adolescent idiopathic scoliosis

Study Design. Prospective clinical cases series. Objectives. To prospectively evaluate outcomes and critically review radiographic results and complications associated with single solid rod anterior spinal fusions in adolescent idiopathic scoliosis with 2-year minimum follow-up (range, 2-6 years). Methods. Ninety consecutive patients at a single institution with thoracic (n = 43) or thoracolumbar/lumbar (n = 47) adolescent idiopathic scoliosis were treated by one of two surgeons with a similar anterior surgical technique using rib autograft, intradiscal structural (Harms) cages placed below T12, and anterior single solid rod convex compressive instrumentation. The patients were evaluated prospectively with the Scoliosis Research Society outcome instrument and upright radiographs before surgery and minimum 2-year follow-up. Results (Radiographic). The average coronal correction of thoracic curves was from 55° to 29° (47%). The average correction of thoracolumbar/lumbar curves was from 50° to 15° (70%). In the sagittal plane, kyphosis was improved in thoracic fusions from 23° to 30° (T5-T12) and lordosis maintained in thoracolumbar/lumbar fusions at -58° (T12-sacrum). Five patients (5.5%) developed a pseudarthrosis, four with implant failure. Three of five required a posterior fusion for a reoperation rate of 3.3%. The fourth and fifth patients were asymptomatic and appeared fused at the 2-year follow-up, with minimal loss of correction. Common risk factors for pseudarthrosis were smoking (4 of 5), weight > 70 kg (4 of 5), and for thoracic pseudarthrosis, hyperkyphosis >40° T5-T12 (2 of 3). Results (Clinical Outcome). Scoliosis Research Society domain average scores were improved for function, pain, and self-image (P < 0.01). With the Scoliosis Research Society satisfaction domain, 88% responded that they were satisfied with their results and 89% would undergo the same treatment again. Four of five patients with pseudarthrosis did not have statistically significant lower final Scoliosis Research Society scores than those with solid fusions (93 vs. 97, P = 0.18). Conclusion. Anterior instrumented fusions for adolescent idiopathic scoliosis using a single solid rod had good radiographic and clinical outcomes. Consideration should be given to alternate techniques in larger adolescents (>70 kg) with thoracic hyperkyphosis (>40°), and smoking should be avoided. Poor radiographic outcomes did not correlate with final Scoliosis Research Society scores.