The Relationship between Increased Intervertebral Disc Height and Development of Postoperative Axial Neck Pain after Anterior Cervical Fusion

OBJECTIVE To evaluate the relationship between postoperative increase in intervertebral disc space height (IVH) and posterior axial neck in cases of degenerative cervical disease treated with anterior cervical discectomy and fusion (ACDF). METHODS A total of 155 patients who underwent ACDF with more than 1 year follow up were included. Radiologically, IVH and interfacet distance (IFD) of the operated segment were measured preoperatively and postoperatively. We clinically evaluated neck and arm pains according to visual analogue scale (VAS) scores and assessed neck disability index (NDI) scores preoperatively, postoperatively, at 3 months, 6 months, and 1 year postoperatively. The relationship between radiological parameters, and clinical scores were analyzed using a regression analysis. RESULTS The mean increase in IVH was 2.62 mm, and the mean increase in IFD was 0.67 mm. The VAS scores for neck pain preoperatively, postoperatively, and at 3 months, 6 months, 1 year postoperatively were 4.46, 2.11, 2.07, 1.95, and 1.29; those for arm pain were 5.89, 3.24, 3.20, 3.03, and 2.18. The NDI scores were improved from 18.52 to 7.47. No significant relationship was observed between the radiological evaluation results regarding the increase in intervertebral height or interfacet distance and clinical changes in VAS or NDI scores. CONCLUSION The increase in intervertebral space or interfacet distance by the insertion of a large graft material while performing ACDF for the treatment of degenerative cervical disease was not related with the change in VAS scores for neck and arm pains and NDI scores postoperatively and during the follow-up period.