Transcanal cochleostomy in cochlear implantation: experience with 50 cases

The traditional access route for cochlear implantation was initially proposed by William House in 1961. Alternatives to this surgical approach have been suggested by many authors. The combined approach technique (CAT) is a variation of the traditional mastoidectomy-posterior tympanotomy method, which uses a transcanal approach to cochleostomy combined with a small mastoidectomy and an equally small posterior tympanotomy for the insertion of electrodes. This paper presents a detailed description of this alternative procedure, reporting our experience with 50 cases, and adds our contribution regarding possible advantages and implications of using a transcanal cochleostomy. The subjects had profound and severe bilateral hearing loss and had not benefited from external hearing aids. They underwent cochlear implantation at Hospital de Clinicas de Porto Alegre from May 2003. The median follow-up was 29 months. All cases were successfully implanted using CAT. No major complications, such as facial paralysis or paresis, meningitis, cholesteatoma, or cerebrospinal fluid leaks, were observed in any patient. The CAT is a safe and efficient variation of cochlear implantation surgery, which is especially appropriate if cochlear calcification or malformations are present, or whenever cochleostomy has to be performed anteriorly, and when the position of the facial nerve prevents an adequate posterior tympanotomy.