Outcomes of active cervical therapeutic exercise on dynamic intervertebral foramen changes in neck pain patients with disc herniation

Background: To better understand biomechanical factors that affect intervertebral alignment throughout active therapeutic exercise, it is necessary to determine spinal kinematics when subjects perform spinal exercises. This study aims to investigate the outcomes of active cervical therapeutic exercise on intervertebral foramen changes in neck pain patients with disc herniation. Methods: Thirty diagnosed C4/5 and/or C5/6 disc-herniated patients receiving an 8-week cervical therapeutic exercise program were followed up with videofluoroscopic images. The dynamic changes in the foramen were computed at different timepoints, including the neutral position, end-range positions in cervical flexion-extension, protrusion-retraction, and lateral flexion movements. Results: The results showed that the active cervical flexion, retraction, and lateral flexion away from the affected side movements increased the area of the patients' intervertebral foramen; while the active extension, protrusion, and lateral flexion toward the affected side reduced the areas of intervertebral foramen before treatment. After the treatment, the active cervical flexion significantly increased the C2/3, C3/4, and C6/7 foramen area by 5.02-8.67% (p = 0.001 similar to 0.029), and the extension exercise significantly reduced the C2/3 and C4/5 area by 5.12-9.18% (p = 0.001 similar to 0.006) compared to the baseline. Active retraction movement significantly increased the foramen area from C2/3 to C6/7 by 3.82-8.66% (p = 0.002 similar to 0.036 with exception of C5/6). Active lateral flexion away from the affected side significantly increased the foramen by 3.71-6.78% (p = 0.007 similar to 0.046 with exception of C6/7). Conclusions: The 8-week therapeutic exercises including repeated cervical retraction, extension, and lateral flexion movements to the lesion led to significant changes and improvements in intervertebral foramen areas of the patients with disc herniation.