Measurement of Milwaukee Brace Pad Pressure in Adolescent Round Back Deformity Treatment

STUDY DESIGN: In this prospective study, we measured the pad pressures of the Milwaukee brace in adolescent hyperkyphosis treatment. PURPOSE: We evaluated the skin-brace interface forces exerted by the main pads of the Milwaukee brace. OVERVIEW OF LITERATURE: A fundamental factor associated with brace effectiveness in spinal deformity is pad force adjustment. However, few studies have evaluated the in-brace force magnitude and its effect on curve correction. METHODS: Interface forces at four pads of the Milwaukee brace were measured in 73 patients withround back deformity (mean age, 14.04±1.97 years [range, 10–18]; mean initial Cobb angle,67.70°±9.23° [range, 50°–86°]). We used a modified aneroid sphygmomanometer to measure the shoulder and kyphosis pad pressures. Each patient underwent measurement in the standing and sitting positions during inhalation/exhalation. RESULTS: The mean pad pressures were significantly higher in the standing than in thesitting position, and significantly higher pressures were observed during inhalation compared toexhalation (p=0.001).There were no statistically significant differences between right and left shoulder pad pressures (p>0.05); however, the pressure differences between the right and left kyphosis pads were statistically significant (p<0.05). In a comparison of corrective forces with bracing for less or more than 6 months, corrective force was larger with bracing for less than 6 months (p=0.02). In the standing position, there were no statistically significant correlations between pad pressures and kyphosis curve correction. CONCLUSIONS: In the sitting position, there was a trend toward lower forces at the skin-brace interface; therefore, brace adjustment in the standing position may be useful and more effective. There was no significant correlation between the magnitude of the pad pressures and the degree of in-brace curve correction.