The Early Effect of Anterior Cervical Discectomy and Fusion on Adjacent Segment Degeneration in Cases of Cervical Degenerative Disease: A Clinical and Retrospective Study

Abstract

BACKGROUND: The cervical spine is the most mobile part of the spine in the sagittal plane. It is important for surgeons to have reliable, simple, and reproducible parameters to analyze the cervical spine pre-operative and post-operative. Despite anterior cervical discectomy and fusion (ACDF) is a common procedure, adjacent segment failure after surgery is an ongoing clinical concern; adjacent segment disease (ASD) occurs in approximately 3% of patients per year, with an expected incidence of 25% within the first 10 years following fusion. It has been suggested that the increased stress placed on adjacent segments after successful ACDF may increase the rate of symptomatic disc disease at those segments, so our study focuses on how to evaluate ASD using magnetic resonance imaging (MRI) and X-ray. METHODS: The retrospective study conducted on 72 patients in the department of neurosurgery at Kasr Al-Ainy hospitals to evaluate ASD after ACDF for degenerative cervical spondylosis using pre-operative and post-operative cervical spine X-ray lateral view as well as MRI for cervical spine after 2 years from the date of surgery. RESULTS: Among the 72 patients in our study, the follow-up MRI after 2 years showed new pathology in 14 patients (19.4%) while 58 patients (80.6%) showed no new pathology; also 20 patients (27.8%) presented with new complaints while 52 patients (72.2%) had no new complaints and only 3 patients (4.16%) were scheduled for surgery. CONCLUSION: ASD is an ongoing process of degeneration that could be accelerated by ACDF procedures, but not every adjacent segment degeneration or symptomatic disease requires additional surgery. Cervical mal-alignment greatly affects the neck pain rather than development of other new neurological manifestations and plays a role in adjacent segment failure which should be considered during cervical fusion surgeries. ASD must be differentiated from adjacent segment degeneration using clinical examination and imaging to help in patients’ follow-up and decision-making of further intervention.