114. Intraoperative conversion of cervical total disc replacement to fusion: incidence and reasons

Abstract

BACKGROUND CONTEXT Cervical total disc replacement (cTDR) currently offers an alternative treatment with results similar or superior to anterior cervical discectomy and fusion (ACDF). There may be conditions identified intraoperatively during cTDR placement that may create a need to convert the procedure to fusion. PURPOSE The purpose of this study was to analyze the incidence and reasons for intraoperative conversions of cTDR to ACDF. STUDY DESIGN/SETTING The study was based on a retrospective review of consecutive cases performed by a spine specialty clinic. PATIENT SAMPLE A database of 1,246 consecutive patients taken to the operating room for cTDR was reviewed. Cases were performed over a 15-year period beginning with the first case experience. OUTCOME MEASURES The outcome measure was the occurrence of intra-operative conversion from cTDR to ACDF. METHODS Cases of attempted TDR converted intraoperatively to a fusion were identified. Operative notes were reviewed in detail to identify the reason for conversion. RESULTS In 0.40% (5/1,246) of patients undergoing cTDR intraoperative conversion to fusion was performed. With respect to the number of operated levels, conversion occurred in 0.32% (5/1,545 levels). Conversion proceeded without complications in all cases. In no case was surgery aborted completely. Reasons for conversion to fusion were as follows: (1) poor vertebral body end plate quality that may not have adequately supported a motion sparing implant; (2) anterior inferior vertebral body was beveled creating an undesirably high risk of migration; (3) patient size (small vertebral bodies with respect to the smallest available implant) and (4) large bridging osteophytes and immobility of a severely collapsed space (n=2 patients). CONCLUSIONS Intraoperative conversion from cTDR to fusion was rarely needed in this series of more than 1,200 patients, including the first case experiences for multiple surgeons. When performed, conversion was accomplished without incident and never was the surgery aborted completely. Ease of conversion may be attributable to the TDR approach being the same as for traditional ACDF. Patients and the surgical staff should be aware of, and prepared for, potential conversion from cTDR to ACDF. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.