Wednesday, September 26, 2018 3:35 PM – 5:05 PM How to Avoid Complications

Abstract

BACKGROUND CONTEXT Rod fracture is known to occur due to delayed fusion or pseudarthrosis following ASD surgery. Rod fracture following radiographic fusion has not been previously investigated. PURPOSE To determine the rate and risk factors for rod fracture after radiographically solid arthrodesis following ASD surgery. STUDY DESIGN/SETTING Retrospective cohort of prospectively collected multicenter data. PATIENT SAMPLE A total of 402 adult spinal deformity patients. OUTCOME MEASURES Rod fracture. METHODS ASD patients in a multicenter prospective database were assessed for radiographic fusion by a committee of three spinal deformity surgeons. Fusions were rated as bilaterally solidly fused (A), unilaterally solidly fused (B), partially fused (C), or no fusion (D). Ratings required agreement of a minimum of two judges. Inclusion criteria were 2-year follow-up and radiographically-confirmed fusion (grade A or B). Patients were defined as rod fracture after fusion (RFAF) if rod fracture was documented following radiographically confirmed fusion. Adjusted analyses were conducted with multiple logistic regression, utilizing backwards variable selection to a threshold of p RESULTS Of 402 patients with solid fusion on 2-year follow-up radiographs, 9.5% (n=38) subsequently suffered RFAF. On multivariate analysis, higher rates of RFAF were seen among patients of age group 60-69 (vs. 18-49, OR 6.28, p=.0091), BMI 30-34 (vs. CONCLUSIONS Rod fracture after fusion occurred in 9.5% of patients with apparently solid radiographic solid fusion following ASD surgery. Advanced age, obesity, smaller diameter rods, stainless steel rods, osteotomy, posterior-only approach, interbody fusion, and lower comorbidity burden were significantly associated with RFAF. This study suggests that assessment of solid fusion by plain radiographs is insensitive to probable pseudarthrosis. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.