Radiographic outcomes and subsidence rate in hyperlordotic versus standard lordotic interbody spacers in patients undergoing anterior cervical discectomy and fusion

Background:Anterior cervical discectomy and fusion (ACDF) is a common surgery for patients with degenerative cervical disease and current interbody spacers utilized vary based on material composition, structure, and angle of lordosis. Currently, there is a lack of literature comparing subsidence rates or long-term radiographic outcomes with hyperlordotic and standard lordotic spacers. This study compares long-term radiographic outcomes, subsidence rate, and rate of fusion in patients who underwent ACDF with hyperlordotic or standard interbody placement. Materials and Methods:Patients who underwent 1-3-level ACDF with either a standard lordosis or hyperlordotic interbody were included. Standard radiographs were evaluated for C2-7 lordosis (CL), sagittal vertical axis, C2 slope (C2S), T1 slope (T1S), subsidence rate, and fusion. Results:Forty-five patients underwent ACDF with hyperlordotic interbody placement and after a 1:1 propensity match with standard lordotic patients, 90 patients were included. 1-year postoperative radiographs demonstrated the hyperlordotic cohort achieved higher CL (15.3 degrees +/- 10.6 degrees vs. 9.58 degrees +/- 8.88 degrees; P = 0.007). The change in CL (8.42 degrees +/- 9.42 degrees vs. 0.94 degrees +/- 8.67 degrees; P < 0.001), change in C2S (-4.02 degrees +/- 6.68 degrees vs. -1.11 degrees +/- 5.42 degrees; P = 0.026), and change in T1S (3.49 degrees +/- 7.30 degrees vs. 0.04 degrees +/- 6.86 degrees, P = 0.008) between pre- and postoperative imaging were larger in the hyperlordotic cohort. There was no difference in overall subsidence (P = 0.183) and rate of fusion (P = 0.353) between the cohorts. Conclusion:Hyperlordotic spacer placement in ACDF can provide increased CL compared to standard lordosis spacers, which can be considered for patients requiring restoration or maintenance of CL following ACDF.