Outcomes Following Anterior Cervical Discectomy and Fusion: The Role of Interbody Disc Height, Angulation, and Spinous Process Distance
Anterior cervical discectomy and fusion (ACDF) is a successful procedure for the degenerative cervical spine. One goal of the fusion is to restore the loss of disc height that results from the degenerative process. Whereas cervical alignment improves with increased disc height, the ideal graft size used for disc space restoration is unknown. Few studies have examined the relationships between these changes in cervical alignment and clinical outcomes.Methods:
All patients underwent a single-level ACDF at the authors' institution. Radiographs at early and final follow-up were examined, and three measurements were made: disc height, disc space angulation, and spinous process distance. These radiographic measurements were correlated with Visual Analog Scales (VASs) for neck and arm pain and Oswestry Disability Index (ODI).Results:
There were significant changes in disc height (5.3 vs 7.0 mm) as well as disc space angulation (3.3° vs 0.1°). Reduction in neck pain VAS score (6.7 vs 3.2) and arm pain VAS score (5.1 vs 2.3) was significant. ODI scores were not statistically different, but improvement of 20.1% was observed. Correlations between radiographic parameters and clinical outcomes were moderate to low, and none was significant.Conclusions:
While restoration of cervical alignment and disc height is important, clinical results are critical in analysis of outcomes following ACDF. We have shown that although clinical outcomes remain good, there does not appear to be any strong correlation with radiographic results. Emphasis on restoration of cervical alignment appears justified, but its influence on clinical outcomes may be overstated.