Segmental Slope is a Predictor of Fusion Rate in Single Level Anterior Cervical Discectomy and Fusion

Abstract

Study design Retrospective study Objectives To explore preoperative segmental slope as a predictor of fusion rate after single-level anterior cervical discectomy and fusion (ACDF). Methods Data of consecutive patients with single-level cervical spondylosis who underwent ACDF between 2011 and January 2019 were retrospectively reviewed. Preoperative parameters including baseline characteristics, segment slope, T1 slope, range of motion, intervertebral disk height, and bone density were evaluated. Data were analyzed using Student’s t-test, Mann–Whitney U test, χ2 test, Fisher’s exact test, multivariate logistic regression analysis, and receiver operating characteristic curve. Results In total, 253 patients were selected. The mean follow-up was 32.1 months (range 24-99 months). Male sex, body mass index, preoperative segment slope, T1 slope, operative levels, and osteoporosis or osteopenia were associated with non-fusion at an early stage after surgery. However, no statistically significant difference was observed at the last follow-up. Multivariate logistic regression analysis revealed that the preoperative segment slope was an independent predictor for non-fusion at 3, 6, and 12 months postoperatively. Osteoporosis or osteopenia was an independent predictor of non-fusion at 6 and 12 months postoperatively. The area under the curve was .874 at 3 months ( P < .001, cutoff value 10.21°), .888 at 6 months ( P < .001, cutoff value 14.56°), and .825 at 12 months ( P < .001, cutoff value 21.08°). Conclusion Preoperative segment slope can be used as a predictor of early fusion rate after single-level ACDF. We determined detailed cutoff values. This study may help surgeons take measures to promote early fusion in advance.

The association of cervical sagittal alignment with anterior bone loss following single-level anterior cervical surgery

“…Surgical level slope may be influenced by the T1 slope, which acts like the abutment of the cervical spine. Sheng et al ( 18 ) found an obvious correlation between T1 slope and surgical level slope. They also determined that increasing surgical level slope was a risk factor for non-fusion at postoperative early stage.…”

“…Cervical sagittal alignment plays an important role in transmitting axial loads and maintaining biomechanical balance of the cervical spine, and might be related to the bone remodeling process after anterior cervical surgery ( 16 ). Studies have suggested that surgical segment slope may influence the intervertebral fusion process after ACDF ( 17 , 18 ). Cervical sagittal vertical axis (SVA) has also been reported to be associated with the anterior bone formation after CDR ( 19 ).…”

Uncovertebral Joint Fusion Versus End Plate Space Fusion in Anterior Cervical Spine Surgery

“…Although a lack of fusion may be asymptomatic, it may potentially lead to complications 13,14 , even a reoperation. In addition, failure to achieve early fusion may result in prolonged neck-brace wear 15 , a delayed return to work, reduced patient satisfaction 16 , and a delayed return to play for athletes 17,18 .…”