Cochlear implant soft surgery: fact or fantasy?

A basic surgical principle is to be as gentle as possible to accomplish the goals of the operation. The concept of "soft surgery" for cochlear implants consisted of a small, localized cochleostomy and gentle electrode insertion, the hope being that by limiting damage to the inner ear, superior hearing results might be obtained. The technique includes deferring the cochleostomy until immediately before electrode insertion, use of a large burr to flatten the promontory, followed by a smaller burr to expose the endosteum, preservation of the endosteum of the scala tympani, smoothing of the bony edges with burrs and dissectors, limited opening of the scala tympani, no suctioning of perilymph, gentle electrode insertion, and potential use of a lubricant to facilitate insertion. Although this technique has a theoretic basis, is esthetically satisfying, and has been used in many cases involving the Nucleus device at multiple centers, no data are available that demonstrate its advantages. Furthermore, the Clarion device, the results of which seem to be comparable to those of the Nucleus device, requires much more extensive and potentially damaging surgery. The pros and cons of soft surgery will be discussed. Although soft surgery seems desirable to limit trauma within the cochlea, other factors such as full electrode insertion, stimulation strategy, and survival of ganglion cells may be more important predictors of successful results.