ERB-YAG AND HOL-YAG LASER OSTEOTOMY - THE EFFECT OF LASER-ABLATION ONBONE HEALING

Sixty-nine male Sprague Dawley rats were divided into three groups of 23 animals each and osteotomies were performed in group 1 with a power saw, in group 2 with the Erb:Yag laser, and in group 3 with the Hol:Y AG laser. Two animals of each group were sacrificed 1 week, 4, 8, and 12 weeks after operation for histologic investigation, and five animal s of each group at 4, 8, and 12 weeks after osteotomy for torque testi ng. Anterior-posterior (AP) radiographs were taken at the same time po ints and investigated for callus formation and development of pseudoar throsis. All tibiae osteotomied with the Hol:YAG laser (group 3) devel oped pseudoarthrosis within 12 weeks and, therefore, torque testing co uld not be performed for this group. Biomechanical measurements of bon e treated by power saw or Erb:YAG laser osteotomies, respectively, sho wed no significant statistical difference in the stability of bone bet ween the two groups. Histologic examination after 1 week exhibited fib rous tissue at the site of osteotomy in rats of all three groups and a dditionally carbonization in rats of group 3. Saw osteotomies resulted in more callus formation than Erb:YAG osteotomies, but both technique s provoked a certain reunion within 8 weeks. Hol:YAG laser-treated ost eotomies, however, exhibited formation of dense fibrous tissue, carbon ization and no callus formation within 12 weeks. Radiographic pictures showed more callus formation for saw osteotomies as compared to those performed with the Erb: YAG laser. For Hol:YAG laser osteotomies pseu doarthrosis was identified also radiologically. (C) 1994 Wiley-Liss, I nc.