Strenge KB, Heller JE, Williams DM, Lemons AC, Shah RV, Nunley PD, Tender GC, Stone MB, McCormack BM, Block JE, Jenkins MB, Slee AE, Summerside EM

Spine (Phila Pa 1976). 2025 Sep 01;50(17):1161-1170. doi: 10.1097/BRS.0000000000005387. PMID: 40331720.

Study design: Prospective randomized controlled trial.

Objective: This trial was designed to understand safety and effectiveness outcomes in subjects with three-level cervical degenerative disc disease treated with anterior cervical discectomy and fusion (ACDF) alone or supplemented with a posterior cervical fusion (PCF) performed using an investigational posterior cervical stabilization system (PCSS).

Background: ACDF remains the most common surgical treatment for cervical disc disease. Long-segment (3+ disc levels) procedures are associated with increased risk of complications including symptomatic nonunion. Supplementing ACDF with PCF to form a circumferential cervical fusion (CCF) improves biomechanical stability but increases the surgical burden for the patient.

Materials and methods: This multicenter study compared outcomes in participants with three-level symptomatic cervical disc degeneration treated with either ACDF or CCF. The CCF procedure incorporated PCF with PCSS. The primary endpoint was 12-month fusion success, defined by bridging bone across the interbody and range of motion <2° across all treated disc levels. The 24-month secondary endpoint was a composite of fusion success, neck disability index (NDI) improvement, neurological status success, and freedom from surgical revision.

Results: This protocol-defined interim analysis included 202 participants with 12-month outcomes and 116 participants with 24-month outcomes. Twelve-month fusion success was higher for CCF (61/100, 61%) compared with ACDF (17/102, 17%) ( P <0.001). The 24-month secondary endpoint was also improved with CCF compared with ACDF [51% (30/59) vs. 23% (13/57); P =0.002]. Revision rates were lower for CCF (1/59, 2%) compared with ACDF (13/57, 23%) ( P <0.001), with 11 of 13 ACDF revisions addressing symptomatic nonunion. Adding supplemental PCF with PCSS did not increase the rates of adverse events (ACDF=65%, CCF=46%, P =0.005).

Conclusions: This study represents the first randomized controlled trial assessing treatment of three-level cervical disc disease. Long-segment ACDF demonstrated low fusion rates and high rates of revision. Adding supplemental PCF with PCSS improved fusion without increasing the risk of surgical complications.

Keywords: anterior cervical discectomy and fusion; cervical spine; circumferential cervical fusion; degenerative disease; fusion; multilevel; nonunion; posterior cervical fusion; pseudarthrosis; randomized controlled trial