The development of a new form of instrument fixation for the OSI CA 6000 spine motion analyzer

The CA 6000 Spine Motion Analyzer (OSI Inc., Union City, CA, USA) is an instrument with a computer interface which utilises electrogoniometry to provide an index of ranges of motion and patterns of movement for the cervical, thoracic or lumbar spines. A new method of securing the instrument on a subject by means of a skin fixation system is described. The design criteria for the new system are detailed along with the development stages required to attain these criteria. It is argued that availability of the CA 6000 with the new skin fixation system described, now provides a practical and ethically acceptable means of providing an accurate index of spinal motion and pattern of movement in both asymptomatic and symptomatic subjects.