The Fate of Adjacent Segments After Anterior Cervical Discectomy and Fusion: The Influence of an Anterior Plate System

Objective: The purpose of this study was to compare anterior cervical discectomy and fusion with cage alone (ACDF-CA) and anterior cervical discectomy and fusion with cage and plate (ACDF-CP) with regard to adjacent segment degeneration (ASD) diagnosed by the use of CT and MRI with retrospective matched cohort design.

Methods: This study enrolled 68 patients who underwent single-level ACDF who were diagnosed with cervical degenerative disc disease and were followed up for at least 2 years with plain radiographs, computed tomography, and magnetic resonance imaging. The patients were divided into 2 groups according to the operation method: ACDF-CA (33 patients) and ACDF-CP (35 patients).

Results: ASD occurred in 4 of 33 patients who underwent ACDF-CA and 9 of 35 patients who underwent ACDF-CP as determined by computed tomography and magnetic resonance imaging. The upper segment range of motion and lower segment range of motion increased in both groups postoperatively. The increase was greater in the ACDF-CP group without statistical significance. The upper segment disc height and lower segment disc height gradually decreased in both groups over time. The decrease was significantly greater in the ACDF-CP group at each follow-up visit. Pseudarthrosis and cage subsidence was observed more in the ACDF-CA group. The pain intensity for the neck in the ACDF-CA group was increased 12 and 24 months postoperatively.

Conclusions: The anterior plate system in ACDF tends to increase adjacent segmental motion and decrease adjacent segmental disc height. In addition, irrespective of clinical symptoms, ACDF-CP has a greater tendency to result in ASD than ACDF-CA after 24 months after surgery.