Five Year Clinical Outcomes Following Anterior Cervical Discectomy and Fusion in Cervical Spondylotic Myelopathy: A Comparison of Polyetheretherketone and Allograft Interbody Spacers

Introduction: Debate remains over choice of interbody graft type in Anterior Cervical Discectomy and Fusion (ACDF). Polyetheretherketone (PEEK) and structural allograft are commonly used interbody spacers in ACDF. Allograft interbody cages come at lower costs to PEEK. The objective of this study was to evaluate the clinical outcomes between the two interbody types.

Methods: A retrospective analysis of the prospectively collected quality outcomes database (QOD) of a high enrolling private practice in the QOD Study Group was performed. Patients with CSM who underwent ACDF with either PEEK or allograft interbody cages were isolated. Patient baseline characteristics and patient reported outcome measures (PROMs) were collected.

Results: A total of 32 patients were identified of which 21 had allograft interbody cages and 11 had PEEK cages. There were no significant variations in baseline patient comorbidities, disability, or underlying pathology between the two cohorts. No significant variation was seen in the number of levels treated between PEEK and allograft (2.09 v. 1.67, p=0.23). Higher postoperative satisfaction was seen in the PEEK group at 12 and 24 months (p=0.03 and p=0.02, respectively) but no difference was observed at 60 months (p=0.34). No significant variation was observed between the two interbody groups in disability at 12 and 24 months. At 60 months, PEEK saw significantly higher NDI (13.5 v. 4.4, p=0.03) and lower MJOA (13.0 vs 15.2, p=0.01) than allograft. There was one reoperation in the PEEK group for ASD and none in the allograft group.

Conclusion : Both PEEK and allograft interbody cages in ACDF demonstrate similar clinical outcomes in the short term, with PEEK showing higher patient satisfaction at 12 and 24 months. However, at 60 months, the allograft group exhibited better functional outcomes, as evidenced by lower disability (NDI) and higher neurological function (MJOA). The results suggest that while PEEK may offer early postoperative benefits, allograft may provide better long-term outcomes. Larger studies with similar follow up durations and radiographic evaluations are needed to discern these differences.