Advantages and Limitations of Zero-Profile Spacers in the Treatment of Cervical Spinal Cord Injury Without Fracture or Dislocation: A 5-Year Retrospective Analysis.

Abstract

Aim: Treatment options for cervical spinal cord injury without fracture or dislocation (CSCIWFD) remain varied. Although zero-profile spacers are widely used in degenerative cervical conditions, their long-term efficacy in CSCIWFD is underexplored. This study compared the five-year outcomes of zero-profile spacers and plate-cage constructs in CSCIWFD.

Material and methods: A retrospective review was conducted on patients undergoing anterior cervical discectomy and fusion (ACDF) for CSCIWFD using zero-profile spacers (n=46) (ZP group) or plate-cage constructs (n=59) (PC group) between June 2014 and December 2019. Neurological function was assessed using the American Spinal Injury Association Impairment Scale (AIS), motor score (AMS), and Japanese Orthopaedic Association (JOA) score. Radiographic parameters included intervertebral height (IH), cervical lordosis, adjacent segment degeneration (ASD), and fusion rate.

Results: The ZP group had shorter operative times and less blood loss than the PC group (P 0.05). Both groups showed comparable neurological improvement. Postoperative IH and cervical lordosis were restored in both groups but declined over time, with greater decline in the ZP group (IH loss: 31.12% vs. 16.38%; cervical lordosis loss: 40.20% vs. 14.98%, P 0.05). The incidence of early and moderate-to-severe dysphagia was significantly lower in the ZP group. Subsidence occurred in 5 of 78 levels in the ZP group and in 1 of 106 levels in the PC group (P 0.05). ASD was observed in 6 ZP vs. 14 PC patients (P 0.05). Both groups achieved complete fusion.

Conclusion: In the long-term follow-up of ACDF for CSCIWFD, zero-profile spacers demonstrated comparable clinical outcomes to plate-cage constructs. While offering advantages like shorter surgical time, reduced intraoperative blood loss, and a lower incidence of ASD, zero-profile spacers had significantly greater loss of correction for IH and cervical lordosis. Surgeons must carefully weigh these risks and benefits when selecting the optimal treatment for CSCIWFD.