Single or double-level anterior interbody fusion techniques for cervical degenerative disc disease.

BACKGROUND: The number of surgical techniques for decompression and solid interbody fusion as a treatment for cervical spondylosis has increased rapidly, but the rationale for the choice between different techniques is unclear. OBJECTIVES: The goal of this study was to determine which method of anterior cervical interbody fusion at a single or double-level provides the best clinical and radiological outcome in patients with degenerative disc disease. SEARCH STRATEGY: Studies were identified with a computer-assisted search of electronic databases in the Cochrane Central Register of Controlled Trials (Issue 1, 2004), MEDLINE (1966 to 2004), EMBASE (1980 to 2004), and Current Contents (1996 to 2004). We also searched references of selected articles. SELECTION CRITERIA: With the aid of a checklist, two reviewers independently screened the identified references. Consensus was reached through negotiation. A third reviewer was consulted if consensus could not be reached. Inclusion criteria included: articles were reports of randomised comparative studies; treatments compared anterior cervical decompression and interbody fusion techniques, participants were individuals scheduled for surgery for a chronic (longer than 12 weeks) diagnosis of degenerative disc disease. DATA COLLECTION AND ANALYSIS: Methodological quality was assessed independently by two reviewers, using the van Tulder list of criteria. With the aid of a data extraction form, data was extracted independently by two reviewers on group characteristics, intervention details and outcome measures. MAIN RESULTS: Fourteen studies with 939 patients evaluated three comparisons of different fusion techniques. From these comparisons it appears that discectomy alone has a shorter operation time, hospital stay, and post-operative absence from work than discectomy with fusion, while there is no statistical difference for pain relief and rate of fusion. It also appears that fusion techniques that use autograft give a better chance for fusion than interbody fusion techniques that use a cage, but other outcome variables could not be combined. REVIEWERS' CONCLUSIONS: The low quality of the trials prohibits extensive conclusions from this review. More studies with better methodology and reporting are needed. There should be a more general agreement between researchers on which outcome parameters should be used in the evaluation of anterior cervical fusion procedures.