Construct type and risk factors for pseudarthrosis at the cervicothoracic junction

Study Design. Retrospective cohort. Objective. The primary goal is to compare the clinical results of 2 types of constructs commonly used at the cervicothoracic junction: small rods (3.2-mm/3.5-mm rods) or transitional constructs. The secondary goal is to perform a case-control study of risk factors for pseudarthrosis at the cervicothoracic junction. Summary of Background Data. Various constructs have been used to stabilize across the cervicothoracic junction; however, no study to date has objectively compared their outcome. Our hypothesis was that both constructs would have similar fusion and complication rates. Methods. A retrospective review of a prospectively collected database revealed 135 patients with the aforementioned constructs and having followed up with imaging at 6 months, 12 months, and 24 months. Univariate analysis comparing the 2 different construct groups was performed. Multivariate analysis for risk factors of pseudarthrosis was also performed. Results. There were a total of 10 patients with pseudarthrosis at 2-year follow-up. There was no difference in pseudarthrosis rate between the small rods (7%) and transitional constructs (8.6%) (P = 0.99). The overall construct lengths were similar (5.8 levels in small rods, 6.7 levels in transitional construct). Blood loss was higher in transitional constructs (574 ± 69 mL) than in small rods (236 ± 53 mL) (P < 0.001). Transitional constructs also had longer operating times (249 min) than small rods (207 min) (P < 0.03). Overall complication rate was higher in the transitional constructs (P < 0.03). Tobacco use, corpectomy, lack of an anterior construct, and construct length were all risk factors for cervicothoracic junction pseudarthrosis in the multivariate analysis. Conclusion. Overall pseudarthrosis rates were similar between small rods and transitional constructs. There was higher complications rate, blood loss, and operating time associated with transitional constructs. Pseudarthrosis risk factors at the cervicothoracic junction include tobacco use, corpectomy, lack of an anterior construct, and longer constructs.