Two-Level Anterior Cervical Discectomy and Fusion versus Hybrid Total Disc Replacement for Bilevel Pathology with Cervical Radiculopathy/Myelopathy: A Comparative Study with a Minimum 2-Year Follow-up in an Indian Population

STUDY DESIGN: Retrospective study. PURPOSE: To study the outcomes of two-level anterior cervical discectomy and fusion (2L-ACDF) versus hybrid total disc replacement (H-TDR) for cervical myeloradiculopathy. OVERVIEW OF LITERATURE: For bilevel disc issues of the cervical spine, 2L-ACDF has been a historical tool with numerous implants used at different time frames. Recent developments in total disc replacement at mobile level with fusion at a spondylotic level known as hybrid fixation have added a new armamentarium for such disorders. METHODS: An analysis of 49 consecutive patients who underwent 2L-ACDF (n=22) and H-TDR (n=27) from January 1, 2014 to December 31, 2017 was performed. Data were studied as retrieved from InstaPACS ver. 4.0 (Mediff Technologies Pvt. Ltd., Bengaluru, India) and medical records. RESULTS: Twenty-two patients with 2L-ACDF and 27 patients with H-TDR were included. The mean±standard deviation (SD) follow-up duration was 4.0±1.5 years in H-TDR and 3.1±1.1 years in 2L-ACDF. The mean±SD Neck Disability Index (NDI) decreased from 26.1±7.6 to 6.5±3.9 in the H-TDR group and from 27.6±7.2 to 6.4±4.8 in the 2L-ACDF group at final follow-up. Disc height at suprajacent level in the 2L-ACDF group was 4.12±0.48 mm, 4.10±0.45 mm, and 4.05±0.48 mm preoperatively, at 1-year, and final follow-up, respectively. Disc height at supradjacent level in the H-TDR group was 4.28±0.36 mm, 4.20±0.32 mm, and 4.19±0.34 mm preoperatively, at 1-year, and final follow-up, respectively. CONCLUSIONS: There was significantly improved NDI in both groups. Adjacent segment disc height loss was greater in the 2L-ACDF group than in H-TDR but not statistically significant (p=0.304). Supradjacent segment range of motion was greater in the 2L-ACDF group than in the H-TDR group (p=0.003). Both findings supported radiographic adjacent segment degeneration (ASD), but symptomatic ASD was absent in both groups.