Assessing range of motion to evaluate the adverse effects of ill-fitting cervical orthoses

Abstract Background context Although previous studies have primarily focused on testing the effectiveness of cervical orthoses under properly fit conditions, this study focuses on analyzing the effects of an ill-fitted cervical orthosis (Miami J). This may have significance to health-care providers in understanding the effects of an improperly fitted neck brace. Purpose The aims of this study were threefold: first, to apply virtual reality (VR) feedback control to repeatedly measure orthoses effectiveness in the primary motions; second, to use this control methodology to test the orthoses ability to restrict flexion/extension (FE) as a function of axial rotation (AR); third, to test the effects of an ill-fitting Miami J on cervical motion. Study design/setting This study combines six degrees of freedom electromagnetic trackers and VR feedback to analyze the effectiveness of common cervical orthoses under less than optimal conditions. Patient sample Twelve healthy male subjects aged 21 to 35 (mean 29.44 years, SD 6.598) years with no previous spinal cord injuries or current neck pain participated in the study. Outcome measures Cervical range of motion (CRoM) measurements were used to determine the amount of motion restriction for each of the fitted (too small, correct size, and too big) Miami J orthoses. Methods One Nest of Birds (NOB) electromagnetic sensor (Ascension Technology) was placed on the head and another on the upper back to measure motion of the head relative to the torso. The VR goggles (i-O Display Systems) were worn so that real-time feedback was available to the subject for motion control. The subject executed the primary motions of FE, AR, and lateral bending (LB) in separate sets of five trials each. Next, in combined motion, the subject axially rotated to a set point and then FE to his maximums. This entire set of motions was repeated for each (soft collar, Miami J, Miami J with chest extension, Sternal Occipital Mandibular Immobilizer (AliMed, Inc.), (SOMI and Halo) as well as the Miami J (one size too small and one size too big); the fitting of each brace was done by a board certified orthotist. A repeated measures analysis of variance was used to determine differences between the tested states (∗p=.05). Results For the validation test, the primary motions recorded for subjects wearing each cervical brace, which demonstrated that the various orthoses all restricted CRoM. The soft collar restricted less motion than the other devices, whe