A simple device to monitor flexion and lateral bending of the lumbar spine.

Monitoring compliance with exercise and motivating patients with lower back pain to perform prescribed exercise regimens are considerable tasks. The objective of this study was to develop and test a low-cost device that can be used by a patient at home to both record and provide real-time biofeedback of lumbar position in the midsagittal and frontal planes during exercises. Our device utilizes strain gages on a thin stainless steel beam to measure lumbar flexion-extension and an optical mouse sensor attached to the end of the blade to measure lateral bending. In comparison tests with a standard electrogoniometer, our device was shown to be accurate within 3 degrees in both the sagittal and frontal planes in healthy subjects. Furthermore, users were capable of reapplying the device themselves and obtaining measurements that were repeatable within 4 degrees in both planes. The capability of this simple device to accurately measure lumbar spine position in a nonlaboratory setting makes it well suited as a tool for providing feedback on exercise performance to both patients and clinicians.