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.