IN-VITRO ANALYSIS OF LASER MENISCECTOMY

Partial meniscectomies were performed on 32 fresh human meniscal autop sy specimens. The following laser systems were tested: carbon dioxide (CO2), neodymium:yttrium aluminum garnet (Nd:YAG), potassium titanyl p hosphate (KTP), holmium:YAG (Ho:YAG), and excimer. Meniscectomies with these lasers were compared with scalpel, mechanical, and electrocaute ry meniscectomies. Lasers were applied to specimens in and out of norm al saline. Routine hematoxylin and eosin and sirius red sections were prepared for each specimen, and the depths of thermal changes were ana lyzed. Scanning electron microscopy was used to visualize the meniscec tomy interface. Among these specimens, the scalpel and mechanical meni scectomies showed the least extension of cellular changes (range, 10-1 5 mm). The excimer laser caused the least tissue changes of the lasers tested. Tissue changes were less extensive with the pulsed CO2 laser than with the holmium:YAG, neodymium:YAG, and KTP lasers. Scanning ele ctron microscopy showed that use of the scalpel meniscectomy resulted in the smoothest meniscectomy edge, followed by use of the excimer, CO 2, holmium:YAG, neodymium:YAG, and KTP lasers. The most surface disrup tion occurred with electrocautery. Meniscectomies under saline require d more energy and took longer in each case, with the holmium:YAG, neod ymium:YAG, and CO2 laser cutting the best. Saline meniscectomies showe d less thermal change. The COL and KTP lasers cut best in air.