Abstract
Abstract: :
Purpose: To determine the quality of Q-switched Er:YAG laser cuts in corneal tissue for penetrating nonmechanical keratoplasty and skin, brain and bone tissue for neurosurgical applications. Methods: Enucleated rabbit eyes were trephined using slit masks (stainless steel 18CrNi) until focal perforation was achieved by Q-switched Er:YAG laser with defined parameters: 0.7 mm spot size, 65 mJ pulse energy, 600 - 800 ns pulse duration, 5 Hz repetition rate. On freshly excised human tissue (skin, bone, brain) laser cuts were performed with the laser using slit or circular mode. The tissue was stained with PAS and the thermal effects were assessed. Results: In rabbit corneas, the thermal zone was 6.9+/-3.0 um in the superficial and 8.1+/-1.7 um in the middle and deeper stroma. The thermal coagulation zone was 4.2+/-1.4 um in spongiotic bone, 6.8+/-1.6 um in compact bone, in skin 8.3+/-3.8 um. The area of cell damage adjacent to laser trephination in brain tissue measured 77.7+/-22.5 um in the superficial layers and 55.0+/-43.8 um in the deeper layers. Conclusion: This first comparison of Q-switched Er:YAG laser effects in different ex vivo tissues demonstrated the smallest thermal effects in bone, corneal and skin tissue. Our studies may be the first step for interdisciplinary use of this laser in ophthalmology and neurosurgery.
Keywords: 374 cornea: stroma and keratocytes • 454 laser • 474 microscopy: light/fluorescence/immunohistochemistry