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

Abstract

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.

Keywords: Cervical radiculopathy; Hybrid total disc replacement; Myelopathy; Two level anterior cervical discectomy and fusion.

Fig. 1

Flowchart depicting inclusion of the patient in the study. 2L-ACDF, two-level anterior cervical discectomy and fusion; H-TDR, hybrid total disc replacement; PACS, picture archiving and communication system.

Fig. 2

Postoperative X-ray at 6-week (A, AP; B, lateral), 3-month (C, AP; D, lateral), 1-year (E, AP; F, lateral), and final follow-up (G, AP; H, lateral) in patient undergoing two-level anterior cervical discectomy and fusion. AP, anteroposterior.

Fig. 3

Preoperative X-ray (A, AP; B, lateral; C, lateral flexion; D, lateral extension), immediate postoperative X-ray (E, AP; F, lateral), 3-month follow-up X-ray (G, AP; H, lateral), and 1-year follow-up X-ray (I, lateral flexion; J, lateral extension) in patient undergoing hybrid total disc replacement. AP, anteroposterior.

Fig. 4

Comparison of (A) Neck Disability Index (NDI) scores and (B) Visual Analog Scale (VAS) scores (arm pain) at various time points between the two groups. ACDF, anterior cervical discectomy and fusion.

Fig. 5

Comparison of (A) average disc height of two levels and (B) supradjacent level at various time points between the two groups. ACDF, anterior cervical discectomy and fusion.