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INTRODUCTION: Anterior cervical discectomy and fusion (ACDF) and cervical disc arthroplasty (CDA) are established surgical options for the treatment of cervical radiculopathy, myelopathy, and cervical degenerative disc disease. However, current literature does not demonstrate a clear benefit between ACDF or CDA. The primary objective of this study is to compare the outcomes of ACDF and CDA for patients enrolled in the Michigan Spine Surgery Improvement Collaborative (MSSIC) database. Secondary objectives include assessment of early complications, procedural/perioperative outcomes, and patient-reported outcome measures after both ACDF and CDA. METHODS: Patients undergoing 1 or 2 level ACDF or CDA surgery were included. A 4:1 propensity score matching analysis was performed between ACDF and CDA, balanced exactly on levels fused/replaced, and using nearest neighbor of propensity scores in common support region. Covariates included in the matching were age, gender, race, education, BMI, diabetes, coronary artery disease, hypertension, COPD, ASA > 2, independent ambulation pre-op, private insurance, levels (which were specified to be an exact match), current smoking status, pre-op daily opioid use, and duration of symptoms. Univariate comparisons were performed both pre- and post-propensity score matching. RESULTS: A total of 10,991 patients undergoing surgery between January 4, 2016 and November 5, 2021 were included in the analysis. After matching, there were 3552 patients in the ACDF group and 888 patients in the CDA group. All discussed results are post-propensity score matching. Demographics yielded significant differences in age (48.8 ± 10.0 years and 46.6 ± 10.8 for ACDF vs CDA, respectively; p < 0.001) and pre-operative scoliosis (11% vs 9%; p = 0.048). Other demographic criteria were similar. There was no difference in preoperative duration of symptoms, foraminal stenosis, or central stenosis (p > 0.05); however, the CDA group had a higher prevalence of disc herniation (p = 0.002) and the ACDF group had a higher prevalence of myelopathy (p<0.001). Preoperative results are presented in Table 1. Regarding outcomes, length of surgery in hours was increased in the CDA group (1.7 ± 0.9 CDA vs 1.5 ± 0.7 ACDF; p < 0.001) while length of stay in days was decreased (1.0 ± 1.0 CDA vs 1.4 ± 1.8 ACDF; p < 0.001). Patients who underwent CDA were more likely to be discharged home (100% CDA vs 98% ACDF; p = 0.002) and experience an outpatient surgery defined as less than 23 hours hospital stay (62% CDA vs 51% ACDF; p < 0.001). Estimated blood loss was similar for both groups (p = 0.089). There was a higher incidence of postoperative complications, including urinary retention, readmission, surgical site infection, return to OR, new or worsening radicular findings, cerebrospinal fluid leak, and myelopathy, in the ACDF group (25% ACDF vs 21% CDA; p = 0.022). At 1 year postop, significantly more patients were satisfied with their surgery in the CDA group (87% CDA vs 82% ACDF; p = 0.049). No significant differences in satisfaction were observed at 90 days or 2 years. No significant differences were observed in PROMIS, EQ-5D, neck pain, and arm pain minimal clinically important differences (MCIDs). Return to work favored CDA at 90 days (78% in CDA vs 71% in ACDF; p = 0.043) and 2 years (92% in CDA vs 83% in ACDF; p = 0.049). Outcome results are presented in Table 2. DISCUSSION AND CONCLUSION: Patients undergoing ACDF and CDA demonstrated similar preoperative characteristics. Postoperatively, patients undergoing CDA were more likely to be discharged home and experience an outpatient procedure. In addition, there were fewer complications in patients who underwent CDA. Furthermore, patients who underwent CDA were more satisfied with their surgery at 1 year and had higher rates of return to work at 90 days and 2 years after surgery. Further investigation is needed to further elucidate the significance of these postoperative benefits seen with CDA.


American Academy of Orthopaedic Surgeons AAOS 2023 Annual Meeting, March 7-11, 2023, Las Vegas, NV