Prevention of complications and failures in endolymphatic system surgery.

Endolymphatic system surgery for Meniere's disease has been shown to be effective in selected cases. However, substantial long term relief of symptoms may not be achieved in some patients in spite of early success and revision surgery may be required. Revision endolymphatic system surgery has been reported as being required in 9.7 to 16.3 per cent of the patients. As part of an ongoing prospective analysis of endolymphatic valve implant surgery, the first 400 procedures we performed over six years were analyzed to determine the incidence and reasons for revision surgery, as well as the incidence and nature of the intraoperative and postoperative complications. Fifty-four (13.9 per cent) of 386 endolymphatic valve implant operations performed by the authors required revision. The results in 14 patients initially operated on elsewhere were also analyzed. The most frequent cause of failure was outflow tract obstruction by temporalis fascia, previously used to anchor the valve. Since that technique has been abandoned, the revision rate of primary valve implants has been 6.7 per cent. The valve implant for hydrops appears to be a safe and effective treatment with a minimum of complications. A thorough understanding of the surgical anatomy as related to surgical technique and instrumentation is essential in minimizing the risk of failure resulting in a revision or a complication. The incidences of complications in the first 400 valve implant operations were: "dead ear" resulting from various causes, 2.5 per cent; transient facial nerve paresis, 0.75 per cent; permanent facial nerve damage, none; cerebrospinal fluid leaks, 4.5 per cent (one requiring surgical closure, 0.25 per cent); wound infections, 1.25 per cent; postoperative malignant hyperthermia, one case (0.25 per cent). There were no cases of meningitis and no deaths. The complications and related factors as well as a failure analysis of the pressure sensitive unidirectional inner ear valve implant for hydrops are evaluated in detail.