Survival Analysis of the First Weaned Patients Treated with the SpineCor Brace

· (a – Sainte-Justine Hospital; b – Biorthex Inc.)

Purpose: The objective of this study is to assess the success of treatment during the follow-up of a group of consecutively treated Idiopathic Scoliosis (IS) patients treated with the SpineCor brace.

Methods: A survival analysis was performed on 68 patients who had terminated treatment from a cohort of 200 consecutively treated patients with the SpineCor since 1994. Each patient underwent a comprehensive evaluation (clinical and radiological) prior to treatment without brace, at 4 month intervals during treatment with brace, at the end of treatment and at follow-up without brace. A survival analysis was performed to estimate the probability of success at 1, 2, 3, 4 years posttreatment without brace. The difference between the initial radiological Cobb angle, and the last available Cobb angle during follow-up without brace was used to define a failure (aggravation of 5 degrees or more) or success (stabilization, correction). The patient cohort was categorized as either less than 30° (G1), and greater than 30° (G2).

Results: For the total group of patients (Initial Cobb angle: 30°±9°) the trend during treatment was a decrease in spinal curvature at three months with a mean difference of 9° (SD: 6°), at termination of treatment (time=23 months) a mean difference of 5° (SD: 7°); and at a follow-up time of 1, 2, 3 and 4 years there was a difference of 2° (SD: 7°), 6° (SD: 5°), 0° (SD: 8°), and 8° (SD: 4°) in reference to the initial condition. The survival analysis (G1 and G2) indicated a cumulative probability of success during follow-up without brace as follows. Year 1: probability (p) =1.00, (Confidence Interval (CI): 1.00 to 1.00) for G1, p=1.00 (CI: 1.00 to 1.00) for G2; Year 2: (p) =.98 (CI: .93 to 1.00) for G1, p=.92 (CI: .82 to 1.00) for G2; Year 3: p=.92(CI: .83 to 1.00) for G1, p=.92(CI: .83 to 1.00) for G2; Year 4: p=.88(CI: .76 to .99) for G1, p=.92(CI: .73
to 1.00) for G2.

Conclusions: This initial cohort of patients demonstrated a general trend of initial decrease in spinal curvature in brace, followed by a stabilisation and/or correction at the end of treatment which was maintained through 1, 2, 3, and 4 years follow-up.

· If noted, the author indicates something of value received. The codes are identified as: a-research or institutional support; b-miscellaneous funding; c-royalties; d-stock options.