Efficacy of Anterior Cervical Discectomy and Fusion on Adjacent Disc Height

Abstract

Aim: Disc height has been described as indicator of disc degeneration and regeneration. This study reviews a single surgeon's series of anterior cervical discectomy and interbody cage implantation. The aim of this study was to examine the disc height of the adjacent segment before surgery and at follow-up and to determine the influence on clinical outcome. Methods and Materials: Lateral radiographs were used to evaluate postoperative intervertebral height. The disc height was measured with a ruler. Only 1 cranial adjacent segment was studied. On each radiograph, the posterior height of the body and the height of the operated disc space were measured. The ratio between these 2 measurements was taken. Results: The preoperative posterior height of the body to the height of the adjacent disc space ratio was 0.31 +/- 0.11, which postoperatively decreases to 0.30 +/- 0.008. The difference from preoperative to postoperative adjacent disc height was statistically significant (P = 0.000). Conclusion: A longer period of evaluation is needed, to see if all these radiographic changes will translate to symptomatic adjacent-level disease.