A review of combined anterior cervical discectomy and fusion with cervical disc replacement for multilevel cervical disc disease

Hybrid surgery is a relatively new surgical technique that combines anterior cervical discectomy and fusion (ACDF) and anterior cervical disc replacement (CDR) to treat multilevel cervical disc disease (MCDD). ACDF has long been the standard operative treatment for cervical disc degeneration. CDR is an alternative treatment that is intended to preserve motion at the index levels but has narrower indications. Complications of ACDF are well described and include pseudarthrosis and adjacent segment degeneration. The rates and severity of complications increase with the number of consecutive levels treated with ACDF. Likewise, risk of instability at the index level, an established complication after CDR, increases with the number of levels treated with CDR. Surgical treatment for MCDD often requires a multilevel construct, and the traditional approach is an all-ACDF or all-CDR construct. However, hybrid surgery utilizes both procedures within one construct, reducing the number of levels being treated in a row with the same operation to theoretically mitigate complications. This review describes the indications, risks, and benefits of each treatment, analyzes the biomechanics, and summarizes the clinical results of various ACDF/ CDR hybrid surgery constructs, and compares them to ACDF-only and CDR-only constructs.