Impact of subsidence on clinical outcomes and radiographic fusion rates in anterior cervical discectomy and fusion: a systematic review

J Spinal Disord Tech. 2014 Feb;27(1):1-10. doi: 10.1097/BSD.0b013e31825bd26d.

Abstract

Study design: Systematic review.

Objective: To provide a systematic review of published literature on the impact of subsidence on clinical outcomes and radiographic fusion rates after anterior cervical discectomy and fusion with plates or without plates.

Background: Subsidence of interbody implants is common after anterior cervical spine fusions. The impact of subsidence on fusion rates and clinical outcomes is unknown.

Methods: Systematic literature review on published articles on anterior cervical discectomy and fusion, which objectively measured graft subsidence, radiographic fusion rates, and clinical outcomes between April 1966 and December 2010.

Results: A total of 35 articles that measured subsidence and provided fusion rates and/or clinical outcomes were selected for inclusion. The mean subsidence rate ranged from 19.3% to 42.5%. The rate of subsidence based on the type of implant ranged from 22.8% to 35.9%. The incidence of subsidence was not impacted by the type of implant (P=0.98). The overall fusion rate of the combined studies was 92.8% and was not impacted by subsidence irrespective of subsidence definition or the measurement technique used (P=0.19). Clinical outcomes were evaluated in 27 of 35 studies with all studies reporting an improvement in patient outcomes postoperatively.

Conclusions: Subsidence irrespective of the measurement technique or definition does not appear to have an impact on successful fusion and/or clinical outcomes. A validated definition and standard measurement technique for subsidence is needed to determine the actual incidence of subsidence and its impact on radiographic and clinical outcomes.

Publication types

  • Meta-Analysis
  • Review
  • Systematic Review

MeSH terms

  • Biomechanical Phenomena
  • Bone Plates
  • Cervical Vertebrae / diagnostic imaging*
  • Cervical Vertebrae / physiopathology
  • Cervical Vertebrae / surgery*
  • Demography
  • Diskectomy / methods*
  • Humans
  • Radiography
  • Spinal Fusion / methods*
  • Treatment Outcome