New minimally-invasive laser treatment in orthopaedics on spinal deformations and bone tumours
Three completely new, minimally-invasive laser operation techniques were developed and extensive investigations were carried out for a clinical application in orthopaedics. With a focus on laser tissue interactions, this work covers a broad range of different applications from cw to femtosecond laser systems. Throughout this work, the emphasis was put on laser tissue interaction and the optimisation of laser parameters with regard to safety and efficiency. Two effects, laser ablation and laser coagulation, were investigated with regard to minimal thermal damage to collateral structures. The main part was the development of a completely new laser-induced operation technique for the minimally-invasive treatment of spinal deformities in young patients. The method is based on endoscopic laser treatment with an anterior (thoracoscopic) surgical approach. In a second application, experiments with a picosecond and a femtosecond-laser system showed that plasma-mediated tissue ablation of cortical bone is possible with sufficiently high ablation rates and accuracy for the clinical application of microsurgical treatment. In a third application, we demonstrated the feasibility of laser-induced interstitial thermotherapy (LITT) of bone tissue as a minimally-invasive treatment of bone tumours (osteoid osteoma). After evaluating three lasers (Ho:YAG, Nd:YAG and diode (940 nm)), we found that thermal penetration and, thus, coagulation of bone tumours is possible for tumour sizes up to 2 cm.
Networked Digital Library of Theses and Dissertations