Effect of a Traction Exercise Neck Brace on Cervical Spondylopathy Radiculopathy: A Clinical Study and Finite Element Analysis

Abstract

Traction of cervical spine is an effective method for the treatment of cervical spondylotic radiculopathy (CSR). In this study, a cervical tractor named traction exercise neck brace (TENB) was used to evaluate its effect on the patients with CSR. Forty CSR volunteers were recruited and randomly divided into two groups. One group was subjected to cervical muscle exercise with TENB under static traction condition. Another group was subjected to (JOBT) as controls. Symptoms of CSR were evaluated by the visual analogue scale (VAS) and neck disability index (NDI). Imaging characteristics were assessed by curvature of the cervical spine and size of the intervertebral foramen. A finite element (FE) analysis model of cervical spine was established by 3D reconstruction to simulate the TENB traction, which evaluates the biomechanical performance. Results showed that TENB significantly reduced scores of VAS and NDI in subjects, and this improved effect on symptoms of pain and radiculopathy is better than that of JOBT. TENB also improved the cervical curvature and enlarged intervertebral foramen at the C4-C6 level. Moreover, FE analysis found that simulated TENB traction increased the spacing of intervertebral foramen, intervertebral disc, and zygapophyseal and uncovertebral joints and changed the stress distribution on the facet joints and nucleus pulposus. This study demonstrates that TENB relieves the symptoms of CSR by adjusting structure of cervical vertebra and restoring its biomechanical performance, which may be a promising instrument in the treatment of CSR.

Figure 1

Effect of TENB on the symptoms of patients with CSR. (a) TENB. (b) Fixation of head and neck posture for vertical traction. (c) Experiment traction by TENB. (d) Conventional traction by JOBT. (e) VAS scores. (f) NDI scores. ^∗∗∗P < 0.001, vs. before treatment; ^††P < 0.01; ^†††P < 0.001, TENB vs. JOBT.

Figure 2

Effect of TENB on the curvature and intervertebral foramen of cervical vertebra. Measurements of cervical curvature by Borden (a) and CCI (b) methods. (c) A 3D model of cervical spine. Size of intervertebral foramen on the left (d) and right (e) sides in the TENB group. ^∗P < 0.05; ^∗∗∗P < 0.001, vs. before treatment; ^†††P < 0.001, TENB vs. JOBT.

Figure 3

Three-dimensional FE model of intact cervical vertebra (C1–C7). (a) Lateral and (b) posterior views of the spine. RP-1, RP-2, and RP-3 indicate the force loading points that simulated the TENB traction.

Figure 4

Effect of TENB on the structure of cervical vertebra. (a) Intervertebral foramen spacing. (b) Zygapophyseal joint spacing. (c) Uncovertebral joint spacing. (d) Anterior and (e) posterior intervertebral disc spacing. Angle values in the abscissa stand for the different angles of traction force.

Figure 5

Internal von Mises stress on cervical vertebra at different simulated angles of traction force. (a) Lateral and (b) anterior views of cervical spine. (c) Maximum tensile stress and (d) maximum compressive stress of nucleus pulposus.