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Microstereo‐Laryngoscopic Lipoinjection: Practical Considerations

INTRODUCTION Brünings introduced injection medialization by means of direct laryngoscopy in 1911. He described injection of paraffin into the paraglottic space to augment the atrophic soft tissues associated with vocal fold paralysis and thereby medialized the excavated musculomembranous region. In 1991, Mikaelian et al. described autologous fat injection for the treatment of vocal fold paralysis. Since then, injection of autologous fat for vocal fold augmentation has become commonplace. Lipoinjection laryngoplasty has been demonstrated to be a safe, efficacious technique for vocal fold augmentation. It has been used for phonosurgical treatment of dysphonia resulting from aerodynamic incompetency associated with paralysis and cancer defects. Although the literature has been replete with articles describing techniques for harvesting and preparation of fat, methods for microlaryngoscopic injection with stereoscopic visualization have not been described in detail. It is a tribute to Brünings that his injection device is still the most commonly used instrument for this purpose. However, the injector was designed approximately 50 years before the introduction of the surgical microscope to laryngoscopy. Therefore, it is not well suited for use given the limited working distance of approximately 20 cm between the microscope and the proximal lumen of the laryngoscope when a typical 400 mm lens is used (Fig. 1). In addition, the narrow-lumen tubular speculae of most laryngoscopes preclude substantial angulation and range of motion of the needle shaft. The problem is exacerbated if there is a micromanipulator from a CO2 laser attached in front of the microscope objective. Previous solutions sacrifice stereoscopic vision or forego magnification altogether. It has even been proposed that the microscope should not be used for laryngeal injections because “it obstructs the instrumentation.” We believe that employing high-powered magnification and stereoscopic visualization of the surgical field during lipoinjection are laudable and achievable goals. This is based on the tenets espoused by the fathers of microlaryngoscopic surgery. The value of microlaryngoscopic lipoinjection with depth perception is further supported by the extensive body of literature describing complications of Teflon injection medialization resulting from technical mishaps of imprecise needle placement. In fact, many current Brünings injection sets contain a needle with a rounded guard several millimeters before the beveled aperture to restrict penetration depth. Given the commonplace performance of lipoinjection, and the paucity of information regarding technical execution, practical considerations for magnified stereoscopic lipoinjection are detailed.