Continuous Passive Motion (CPM) is a long tested and successful therapy for the relief of pain caused by trauma to the knee and other joins. It produces a stressless motion for the pain affected joints. It is used by sports medicine physicians, surgeons and physical therapists throughout the U.S. and the world.

Once patients pass the initial phase of acute mechanical back pain, the benefits of rest diminish, Prolonged rest may lead to unnecessary pain, functional deterioration, and disability. Active self-care exercise can speed the recovery of comfort and function. For some patients, carefully chosen exercise can centralize pain from its peripheral location to the back and even eliminate it. Mechanical continuous passive motion (CPM) of the spine is a new approach to providing spinal activation. It shows promise as an adjunct for patients who exercise and for patients who will not or cannot follow a regular exercise program. When back pain makes sitting a problem, a lumbar support that provides seated CPM may be the solution. Postoperative CPM can help patients improve flexibility after lumbar surgery.

Prolonged sitting commonly causes low back pain and secondary disability. Recently a continuous passive motion device (CPMD), consisting of a cyclically inflated lumbar support bladder, has been shown to improve sitting comfort and to reduce fatigue and subjective stiffness. In a previous study, these benefits were associated with lumbar lordotic motion measured by a flexible ruler technique. The purpose of this study was to measure this motion more directly with radiographs of the spine.

Two male subjects sat with the CPMD centered at L3. While the CPMD was cyclically inflated and deflated at customary, maximally comfortable pressures, sagittal spinal motion was recorded fluoroscopically and with radiographs at the beginning and end of inflation. L1-S1 lordotic angle changes were 29 and 41 degrees (Cobb technique) and 11 and 12 decrees (NIOSH technique) for the two subjects.

Spinal lordotic excursions in this study were very similar to those measured by flexible ruler and associated with improved comfort in previous studies. The CPMD appears to be safe in that the observed maximum lordosis angles were similar to those previously reported for people sitting with 4-cm thick lumbar supports, and the sagittal spinal movements resembled those seen when people rise from sitting to standing.

CONTINUOUS PASSIVE MOTION IN SEATING:A NEW STRATEGY AGAINST LOW BACK PAIN

Vermont Rehabilitation Engineering Center, Department of Orthopaedics and Rehabilitation, McClure Musculoskeletal Research Center, University of Vermont, Burlington, Vermont, USA

Low back pain commonly reduces tolerance for the prolonged sitting required by many occupations and routine daily activities. In order to provide lumbar lordotic continuous passive motion (CPM), a pneumatic device was developed. This device includes a lumbar support bladder, which is cyclically inflated and deflated by a pump and valve system. This system is controlled by a timer and by pressure feedback from the bladder. The user selects cycle duration and peak support pressure. Using a simulated automobile setting, the first part of this study demonstrated that CPM produces lumbar lordotic motion and improved comfort for subjects without histories of this study demonstrated that CPM produces lumbar lordotic motion and improved comfort for subjects without histories of low back pain. In the second part of the study, 28 people with chronic low back pain reported greater comfort using CPM during their routine motor vehicle operation. Further research is needed to determine whether this promising new strategy against low back pain can reduce occupational disability due to sitting intolerance.

This article was presented to the International Society for Study of the Lumbar Spine in Marseilles, France. The authors were awarded first prize for their presentation.