Osteogenese nach Laserosteotomie mit einem CO2-Laser im Vergleich zur Osteotomie mit konventioneller Sägetechnik - eine tierexperimentelle Studie

Laser osteotomy has several potential advantages in comparison to classical bone incision by mechanical saws. In previous studies the bone healing was delayed due to the damage of the thermal effects compared to mechanical instruments like the bone saw. With 7 Beagles as an experimental model, a comparative study was done to assess the healing of bone in response to osteotomy by a new modified carbon dioxide laser system and a mechanical bone saw. Using sterile technique, an approximately 6 mm deep incision was made in the ventral aspect of both mandibles with each method. During the follow-up period three intravital stains were injected to mark the surface of new-bone growth. After the dogs were killed 22 days following the surgical procedure the tissue response was examined by polychrome sequential labelling and undecalicfied paragon-stained ground sections. The sawed mandibles demonstrated a retarded rate of healing and a persistent superficial defect at the impact site. The results of the laser group were quite different. Some of the specimen showed a similar delay in bone healing like in the saw group. In some cases a large layer of carbonised debris was recognized. This retarded healing was most likely due to a surface deposit of charred tissue elements, produced by the thermal effects of the laser. In a third group of laser specimen showed a complete reconstruction of the incision by new Haversian bone and no signs of any damage by thermal effects due to the laser application. This modified carbon dioxide laser appears to be an effective and precise bone ablator. According to the results of previous studies the appearance of carbonisation could be prevented in some cases. If the key is found to reduce the risk of carbonisation to the maximum the future is open for the laser in orthopaedic surgery.