Innovative Apparatus for Quantitatively Evaluating Effectiveness of Cervical Orthosis and Cervical Thoracic Orthosis
Accurate and objective evaluation of the effectiveness of cervical orthosis and cervical thoracic orthosis in restricting neck motion is essential for making clinical decision. Existing methodologies, however, are either not cost-effective or incapable of offering consistent and/or objective outcomes. The objective of this study was to develop and evaluate a cost-effective apparatus which is capable of delivering controllable loading to the head and neck in all three anatomical planes. The apparatus consists of a custom helmet and an instrumented T-handle, allowing the experimenter to apply a force couple in each of the three anatomical planes. Twenty-seven young healthy subjects participated in the evaluation study with cervical orthosis and cervical thoracic orthosis. Four trials were conducted in each plane and the signals of torque and three-dimensional motion sensors were collected simultaneously. Intra-class correlation coefficients (ICCs) of intra-rater reliability ranged from 0.916 to 0.996 for flexion, extension, and lateral bending. ICCs of intra-rater reliability ranged from 0.762 to 0.967 for axial rotation. ICCs of loading and unloading were comparable across test conditions. A similar pattern was revealed in inter-rater reliability. When the experimenter held the T-handle using both hands, a force couple formed, producing a primarily rotary effect. The relatively low reliability in axial rotation might be attributed to the deficiency of cervical orthoses in effectively restricting neck motion in the transverse plane. The apparatus will be a useful tool and offer both quantitative and objective biomechanical evaluation of cervical orthoses.