RESUMEN
STUDY DESIGN: Biomechanical volunteer study. OBJECTIVE: To quantify the stabilizing effect of 2 different semirigid thoracolumbar orthoses during various body movements. SUMMARY OF BACKGROUND DATA: Various spinal diseases need to be treated by immobilization. The literature shows, that the immobilizing effect of orthoses strongly depends on the orthosis design and on the loading direction. Few data are available for loading directions other than flexion and extension. METHODS: Ten young and healthy volunteers (22-44 yr, 5 male, 5 female) performed 4 different tasks: full active flexion/extension, lateral bending, and axial rotation as well as a full active everyday movement (flexion plus lateral bending plus axial rotation). These tasks were carried out without orthosis, with the DorsoFX (BORT GmbH, Weinstadt-Benzach, Germany) and with the SofTec Dorso orthosis (Bauerfeind AG, Zeulenroda-Triebes, Germany). The flexibility of the spine was measured using a 3-dimensional motion capturing system (Zebris Medical GmbH, Isny, Germany). Additionally, the pressure exerted by the orthoses on the subject's body surface was measured using a pressure sensor (Tekscan Inc., South Boston, MA). RESULTS: The range of motion significantly decreased in all loading planes by 42% to 69%. The movement with the largest decrease was axial rotation and the smallest decreases were observed in extension (DorsoFX), flexion and the everyday movement (SofTec Dorso), respectively. The differences between the 2 orthoses were small and not statistically significant. The pressure between orthosis and the body surface was similar for both orthoses but differed between the movements. CONCLUSION: Both orthoses had a similar stabilizing effect on the thoracolumbar spine. The stabilizing effect differed between the 4 movements, which indicates that all loading planes should be tested to understand the effect of an orthosis completely. Complete immobilization of the thoracolumbar spine was not possible with either of the 2 orthoses, but the stability increase was statistically significant. LEVEL OF EVIDENCE: N/A.
