COMPARISON OF THORACOSCOPIC AND OPEN THORACIC DISKECTOMY IN A LIVE OVINE MODEL FOR ANTERIOR SPINAL-FUSION

Study Design. The authors undertook a randomized comparison of 30 thor acoscopic and 30 open thoracic discectomies for anterior spinal fusion in a live sheep model. Objectives. To compare in a live sheep model d iscectomies performed using a thoracoscopic technique with those using an open thoracotomy technique to validate the efficacy of thoracoscop ic disc and end plate removal for potential fusion. Summary of Backgro und Data. in 1993, Mack and Regan described a technique for video-assi sted thoracic surgery that resulted in less morbidity than open techni ques, Subsequent reports support the finding that thoracoscopic spinal surgery results in less morbidity. Methods, Sixty discectomies were p erformed in 10 live sheep. In each sheep, three randomly selected disc ectomies were performed thoracoscopically, and, subsequently, three op en discectomies were performed. The animal then was killed, and the sp ine was sectioned and analyzed by computer imaging. Results. Statistic al analysis found no significant difference in the amount of disc rese cted (t' = 1.9639, t(0.025, 60) = 2.000, alpha = 0.05). The mean perce ntage of disc resected was 67.8% (range, 0-92.2%) in the thoracoscopic group and 76.1% (range, 44.9-95.4%) in the open group. More than 50% of the disc was excised in 27 of 30 spines (90%) in the thoracoscopic group and in 29 of 30 (96.7%) in the open group. This difference was n ot statistically significant (theta(20.05.1) = 3.84, theta(2') = 1.07) , Conclusion. The findings in this study indicate that the thoracoscop ic discectomy technique is equivalent to the open technique in the amo unt of disc and end plate resected. In addition, these findings sugges t that thoracoscopic discectomies provide adequate disc resection to p rovide for an acceptable fusion rate according to the criteria demonst rated by Bunnell in 1982 and therefore support the efficacy of a thora coscopic technique for anterior spinal infusion.