RADIOGRAPHIC AND CLINICAL FOLLOW-UP REVIEW OF CASPAR PLATES IN 49 PATIENTS

Although they are excellent clinical tools, Caspar anterior cervical p lates have not been studied closely with regard to their mechanisms of failure. As more extensive operations are contemplated on older, sick er patients, it is imperative to know when a plating system might be p rone to failure and what the mechanism of that failure might be. There fore, the authors reviewed 49 patients undergoing Caspar plate placeme nt in whom sufficient radiographs were obtained to determine if the fa te of the hardware was related to the patient's age, type of operation , and the length of construct. Eleven of 49 patients suffered hardware failure, defined as any amount of screw backout or breakage, plate pu llout, or pseudarthrosis. Four patients underwent hardware removal; on e underwent posterior fusion for pseudarthrosis. Only two required tre atment in a halo brace. There was an eventual fusion rate of 100%, inc luding one fibrous union, and one of the patients who underwent repeat surgery was lost to follow-up review. No graft extrusions or new neur ological deficits were incurred as a result of hardware failure. Plate length predicted plate failure in a statistically significant manner. Increasing age and reoperation correlated with plate failure but were not statistically significant in this small number of patients. Teles coping of the bone graft and vertebral bodies, with concomitant migrat ion of the plate and slippage of the screws, was common. However, tele scoping was more profound in the group in which the plates failed. The authors conclude that Caspar plate failures are more likely to occur in the elderly and in patients who need longer constructs. Bone fusion can be expected even when the hardware loosens.