Lasers in surgery and medicine
-
Comparative Study
Ablation of porcine ligamentum flavum with Ho:YAG, q-switched Ho:YAG, and quadrupled Nd:YAG lasers.
Ligamentum flavum (LF) is a tough, rubbery connective tissue providing a portion of the ligamentous stability to the spinal column, and in its hypertrophied state forms a significant compressive pathology in degenerative spinal stenosis. The interaction of lasers and this biological tissue have not been thoroughly studied. Technological advances improving endoscopic surgical access to the spinal canal makes selective removal of LF using small, flexible tools such as laser-coupled fiber optics increasingly attractive for treatment of debilitating spinal stenosis. Testing was performed to assess the effect of Ho:YAG, Q-switched Ho:YAG, and frequency quadrupled Nd:YAG lasers on samples of porcine LF. The objective was to evaluate the suitability of these lasers for surgical removal of LF. ⋯ The Ho:YAG, Q-Switched Ho:YAG, and frequency quadrupled Nd:YAG lasers were shown to remove ligamentum flavum (LF). A single pulse of the Ho:YAG laser was shown to cause tearing of the tissue and a large zone of necrosis surrounding the laser-hole. Multiple pulses of the Ho:YAG and Q-Switched Ho:YAG lasers caused charring around the rim of the laser-hole, though the extent of charring was more extensive with the Ho:YAG laser. Charring caused by the Ho:YAG laser was shown to be mitigated by continuously flushing the affected LF with saline during irradiation. The Nd:YAG laser was shown to ablate LF with no gross visible indication of thermal damage to surrounding LF.