Endoscopic Tympanoplasty

Rationale for Endoscopic Approach

This chapter will review the preoperative work-up, indications, surgical technique, and postoperative care of tympanoplasty using an endoscopic approach for the repair of a tympanic membrane perforations. When compared to the traditional microscopic approaches for middle ear surgery, advocates of total endoscopic ear surgery (TEES) cite its distinct advantages of improved visualization and access to middle ear structures, no postauricular incision or scar, decreased postoperative pain, and augmented teaching ability for surgical trainees. Improved visualization also facilitates access to the anterior tympanic membrane without a postauricular incision, which may be beneficial in repairing anterior tympanic perforations using a minimally invasive technique. In patients with narrowed or particularly curved external auditory canals (EAC), the endoscopic approach may be useful for improved visibility and decreases the requirement for canalplasty in certain cases while accessing the tympanic membrane and middle ear.

Despite the potential advantages, an endoscopic approach has limitations that impact the surgeon and patient. The surgeon is limited to a single-handed surgical technique, as the non-dominant hand is typically used to hold the endoscope. Additionally, endoscopes provide a two-dimensional surgical view, compared to microscopes which provide binocular depth perception. However, this limitation can be overcome by maneuvering the endoscope to create a sense of spatial relationships among the structures. Finally, as with every new surgical technique, there is a learning curve that initially impacts surgical efficiency and efficacy.

Preoperative Evaluation and Patient Selection

Regardless of the surgical approach, the principles of preoperative evaluation for a patient with a tympanic membrane perforation remains the same. A complete preoperative clinical history is obtained, with attention focused on the otologic history. A thorough otologic examination with either an otoscope or operative microscopic is undertaken. The endoscope can be utilized both for examination and documentation in the clinical setting, as images from the endoscopic examination can be saved to the electronic medical record for future comparison and surgical planning. Audiologic testing prior to surgery is required and typically includes pure tone average thresholds, tympanometry, and speech discrimination testing. Imaging is not routinely obtained in patients with tympanic membrane perforations without clinical evidence of cholesteatoma, chronic otitis media, or other middle ear pathology. Imaging or further evaluation may be considered if the clinical history and examination do not align with the severity of hearing loss.

During the preoperative consultation, the risks and benefits of both microscopic and endoscopic approaches are described in detail to patients, as the surgeon needs to be prepared to change to a microscopic approach in cases of severe bleeding or if an ear canal is too narrow. Candidates for endoscopic tympanoplasty must have an EAC that is wide enough for both the endoscope and instrumentation. Typically, access to the tympanic membrane can be determined with the use of an endoscope during the preoperative clinical examination. At this stage, the ear canal anterior bulge must be evaluated, and consideration must be given to performing a canaloplasty. In general, most patients with a tympanic membrane perforation are candidates for a transcanal endoscopic approach.

Preparation in the Operating Room