Fate of Posterior Osteophytes in Fused Segments After Anterior Cervical Discectomy and Fusion

Abstract

Prospective cohort study. To investigate the fate of posterior osteophytes after anterior cervical discectomy and fusion (ACDF) using computed tomography. As a method of ACDF, indirect decompression through interbody height distraction and spontaneous posterior osteophyte resorption has the advantage of reducing complications that can occur during direct decompression. However, the outcome of resorption, of the posterior osteophytes, has not been considered to be satisfactory. Thirty-one patients underwent ACDF with plate fixation for cervical spondylotic radiculomyelopathy. The areas and lengths of the most prominent posterior osteophytes in each patient and the anteroposterior diameter of the intervertebral foramen were measured from computed tomographic images using commercial software. Among 31 patients, the posterior osteophytes decreased in 7 (23%), increased in 5 (16%), and were unchanged in 19 (61%). The mean change of area of prominent posterior osteophytes (ΔArea(5 years - 3 months)) was -0.42 ± 4.21 mm. There was no statistically significant change between Area(3 months) and Area(5 years) (P = 0.82). The mean change of length (ΔLength(5 years - 3 months)) was -0.02 ± 0.41 mm. There was no statistically significant difference between Length(3 months) and Length(5 years) (P = 0.84). The mean anteroposterior diameter of each intervertebral foramen of fused segments did not change significantly between 3 months and 5 years postoperatively on oblique foraminal images (C5 Rt. P = 0.31, Lt. P = 0.56; C6 Rt. P = 0.61, Lt. P = 0.49) and axial images (C5 Rt. P = 0.61, Lt. P = 0.49; C6 Rt. P = 0.71, Lt. P = 0.51). Contrary to previous reports, there was no evidence of consistent posterior osteophyte resorption during 5 years of follow-up.