Cervical orthoses.

A biomechanical study is presented to compare the effectiveness of three types of off-the-shelf cervical orthoses and one custom-fit collar in restricting cervical spine motion. A group of 10 normal subjects was studied. The measurements of flexion and extension, lateral side flexion and axial rotation were recorded using various measurement techniques. Interface pressures at the chin and occiput were also measured, along with the warming effect of the collars. The results indicated that all the collars restricted neck movements, for example, the Plastazote collar by 50% of flexion and extension, and that there was no significant difference between off-the-shelf Plastazote and custom-fit collars in restricting movement. Significantly high interface pressures were recorded at the chin, with the subjects wearing the hard and Plastazote orthoses. The warming effect of the soft collar was equal to that of a wool scarf. The study was aimed at improving prescription and although the subjective observations were not validated, the subjects concluded that the custom-fit collars were more comfortable; an important point with such a high rejection rate.