Standardization of Criteria for AIS Brace Studies - SRS Committee on Bracing and Non-operative Management

Purpose: To establish consistent parameters for future AIS bracing studies so that valid and reliable comparisons can be made. As prior literature lacks consistency for both inclusion criteria and brace effectiveness, clinicians are currently unable to draw valid conclusions from existing data.

Methods: A thorough review of published natural history studies was performed to determine the AIS patient population most at-risk for curve progression (and the subsequent possible need for surgery). Then, 31 bracing articles including the current BrAIST proposal were analyzed to determine 1) inclusion criteria that will best identify those patients most at-risk for progression 2) the most appropriate definitions for bracing effectiveness, and 3) identification of additional variables which would provide valuable information.

Results: S: Early studies either lacked inclusion criteria or were quite varied in age at brace prescription (4- 18.9 years), skeletal maturity (Risser 0-4), and curve magnitude (120-680). In more recent studies, inclusion criteria narrowed considerably; specifically, Risser 0-2, age e” 10 years at brace prescription, and primary curves between 250-450 (250-390 in the current BrAIST proposal). Curves 200-250 were included in some studies if progression had been documented. Brace effectiveness was usually defined as the prevention of curve progression d”50 at maturity. However, maturity was variably defined as the end of growth, Risser 4, or two years post-menarchal. Most commonly, bracing was described as ineffective when curve progression was e”60 or if surgical intervention was recommended. Less frequently, bracing was described as ineffective when progression was e”100, if the curve progressed to > 450, or if there was change to another brace. In those studies with follow-up e”2 years beyond maturity, additional curve progression (ultimately leading to surgical intervention) was not unusual. Potentially useful additional variables included: curve patterns, curve grouping (250-350, 300-400, 350-450), brace type, in-brace correction, and amount of daily time in brace.

Conclusions: I. Inconsistent selection criteria in many older bracing studies prevent clinicians from drawing valid conclusions about the effectiveness of bracing in AIS. II. Optimal inclusion criteria for future AIS brace studies consist of age e”10 years old when brace is prescribed, Risser 0-2, primary curve angles between 250 and 390, and no prior treatment. III. Assessment of brace effectiveness should include: 1) the percentage of patients who have d”50 curve progression and the percentage who have e”60 progression at maturity 2) the percentage of patients who have had surgery recommended/undertaken at maturity (surgical indications must be documented), and 3) two-year follow-up beyond maturity to determine the percentage of patients who subsequently undergo surgery (again, surgical indications must be documented). IV. All patients, regardless of subjective reports on compliance, should be included in results (intent to treat). Whenever possible, compliance should be measured objectively. V. All studies should provide results stratified by curve type and size grouping.