Ultrasonic measurement of lumbar canal diameter: a screening tool for low back disorders?

Preventive screening measures for low back pain are limited. Despite considerable evidence that anatomic narrowing of the lumbar spinal canal is a risk factor for specific back problems, difficulty in measuring the canal without unacceptable radiation exposure, cost, or discomfort has limited the assessment of its clinical significance. Using ultrasound to measure the lumbar canal is relatively easy to do, and provides accurate values. In this paper we review the reports on this use of ultrasound, including our own experience in a case control study, and discuss the potential use of ultrasonic measurement as a screening tool to identify narrow lumbar canals.