Cervical traction therapy with and without neck support: A finite element analysis.

BACKGROUND: Cervical traction is commonly used for treating neck pain. However, few studies have investigated the biomechanical impact such traction has on soft tissues.

OBJECTIVES: To analyze the biomechanics of cervical traction therapy in a supine position with and without neck support (NS and non-NS).

METHODS: A finite element model of the cervical spine was constructed to investigate the mechanism behind cervical traction therapy. An axial traction force of 100-N was loaded on the upper surface of C0 to simulate traction weight. Neck support traction was simulated by additionally constraining anterior-posterior motion of the surface of the C4 vertebral lamina. The average von Mises stress, tensile force and motions of related tissues were calculated and compared between the two conditions. Stress in the posterior annulus fibers under flexion was also recorded for comparison.

RESULTS: At the C4-C5 and C5-C6 levels, NS traction resulted in less of a decrease in the lordotic angle. At these levels, the highest average stress was distributed in the posterior annulus fibers with non-NS traction and both traction therapies produced greater stress on the posterior annulus fibers than physical flexion. The intradiscal pressure in all intervertebral discs between C4-T1 decreased during both traction therapies.

CONCLUSION: Neck support traction therapy produced less tension on the posterior annulus fibers and ligaments posterior to it at the C4-C5 and C5-C6 levels. In order to minimize the potential harm to soft tissue in clinical practice, it may be beneficial to use a neck support according to the targeted level.