Analysis of the corrective forces exerted by a dynamic derotation brace (DDB)

Abstract

Background: Discrepancies exist in the current literature for bracing of spinal curvature conditions. This can be explained by the diversity of brace types, the different curve patterns and the various measurement methods and instruments. Objectives: The aim of this study was the analysis of the corrective forces exerted by a dynamic derotation brace (DDB), at the skin-brace interface, altering the strap tension and body posture. Study Design: We analysed the direct forces exerted by a DDB's main pad, on 44 (38 girls, 6 boys) idiopathic scoliotic patients. Twenty-seven patients had a single right thoracic and 17 a single left or right thoracolumbar curve. Methods: We used the F-Socket 9801 pressure sensor and the MatScan Research BETA STAM 6.30 software, while patients adopted nine different postures. The patients were divided into three different groups: those who wore the brace for the first time, those who were changing their brace for a new one, and those who were having adjustments made to their existing brace. Results: These patients who were having adjustments made to their existing brace caused the highest mean exerted force. Changes in strap tension and body posture resulted in statistically significant alterations of the interface pressure and the forces exerted on the patient's body. Conclusions: Tightening the brace's straps always produces a significant force increase, independent of the body posture and the curve type. Also there are some body postures which significantly modify the exerted force. The body posture of maximum inspiration for thoracolumbar curves and, additionally, prone and lying left for thoracic curves. Clinical relevanceAnalysis of forces does not provide information on the correction of spinal curvature, but seem to be helpfully trying to achieve the brace's optimal fit and the best therapeutic result.

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

“…We found no significant correlation between the magnitude of pad pressures and the degree of achieved radiographic in-brace curve correction ( r =−0.08, p =0.47). These findings were confirmed by previous studies for adolescents with idiopathic scoliosis who had been managed with the thoracolumbosacral orthoses [ 9 11 16 ].…”

“…Also, in-brace pressure in the standing position was higher than that in the sitting position. In contrast, van den Hout et al [ 16 ] and Loukos et al [ 9 ] reported higher pad pressures in the sitting than in the standing position, using a Boston brace and dynamic derotation brace. However, Pham et al [ 11 ] and Aubin et al [ 17 ] did not observe any differences in thoracic pad pressures of the thoracolumbosacral orthosis in either the sitting or standing position in scoliotic patients.…”

“…In a study by Pham et al [ 11 ], strap tension was increased by 2 cm and the mean in-brace pressures were increased significantly. In another study by Loukos et al [ 9 ], there was a significant increase in the in-brace pressure when the strap tension was maximum. Indeed, if brace effectiveness depends on how tightly the brace should be fastened, a standard tension may be set in each strap.…”

“…Some studies were conducted to analyze the skinbrace interface pressure at different strap tensions while the subjects take on different positions and activities [ 9 11 17 19 20 ]. In these studies, results showed that tightening the brace's straps can produce a higher in-brace force, but different brace types, various curve patterns, and dissimilar application methods were used; the resulting data disparity hindered any conclusion.…”

“…Adjustment of pad force is a fundamental issue associated with in-brace curve correction and brace effectiveness, but few studies have evaluated the magnitude of these corrective forces [ 9 10 11 ]. For example, Loukos et al [ 9 ] assessed interface forces in a dynamic derotation brace by a PEDAR system in different postures. Pham et al [ 11 ] evaluated the pressure of corrective pads in the Chêneau brace by the Tekscan Clin Seat type 5315 sensor.…”