Desenvolvimento de protótipo para aplicação do laser de CO2 na laringe humana a curtas distâncias

• Autor(a) principal: Morgado, Plínio F. [UNIFESP]
• Data de Publicação: 2002
• Outros Autores: Wagner, Paulo [UNIFESP], Neves, Luciano R. [UNIFESP], Pontes, Paulo A. De L. [UNIFESP]
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNIFESP
• Texto Completo: http://dx.doi.org/10.1590/S0034-72992002000200008; http://repositorio.unifesp.br/handle/11600/1370
• topic: laryngoscopy; endoscopic surgery; laser; larynx; laser; laringoscopia; microcirurgia; laringe

Introduction: Laser endolaryngeal surgery has been performed with 350 and 400mm focal length (f ) lenses which converge the laser beam to a minimum spot size, called beam waist. The beam waist size can be described as: 2omega0 =lambdaf /pw², where lambda is the CO2 wavelength and 2omega is the beam diameter. We developed an optical system which produces a very small beam waist. This small shaft of laser is delivered precisely on the target resulting in a reduced impact spot size enhancing precision and lessening surrounding tissue trauma on laryngeal surgery. Aim: To present an optical system which delivers the laser beam at a small distance from the human glottis. Study design: Clinical trial. Material and Methods: The manufactured prototype has two metallic cylindrical shafts joined in a 135º angle from the horizontal. A coated mirror positioned in its joint change the ray path in the same angle. Two coated lenses converge the laser to a calculated beam waist. The hand piece was coupled to the laser articulated arm and the system was set to 0.5 - 2.0 W at 0.05 sec. exposure time. Laryngeal exposure was achieved with the angled videolaryngoscopy. Three patients with vocal fold polyp underwent laser surgery with the technique above described. Results: A beam waist ranging from 200 to 250 mum was obtained (lambdaCO2 = 10,6 mum). The technique offered adequate laryngeal exposure and satisfactory image quality for a proper laser application. No technical difficulties nor major bleeding or mucosal charring was observed during the treatment. No excessive scarring was observed in a two-month follow-up laryngoscopy. Conclusion: The developed prototype produced very small laser shafts which are useful in the treatment of vocal fold polyps.