Multicenter evaluation of the digisonic SP cochlear implant fixation system with titanium screws in 156 patients

We describe and evaluate the process of fixation of the Digisonic SP cochlear implant with two titanium screws.

The characteristics of this implant allow cochlear implantation using a minimal incision, a subperiosteal pocket, and fixation with two titanium screws, without drilling a custom-fitted seat or creating suture-retaining holes in the skull. The fixation system relies on two tailfins for use of osseo-integratable screws, incorporated into the cochlear implant housing. The first version of this fixation system was modified after a case of device migration: the size of the titanium insert inside the silicone tailfin was increased. Data on 156 patients (8 months to 86 years of age) from a 4-year period in 6 cochlear implantation centers were retrospectively evaluated. Ten patients have undergone bilateral implantation.

Of 166 implantations, 4 postoperative infections and 1 device failure after head trauma were reported. No cerebrospinal fluid leaks or epidural hematomas were reported. One device migration was observed in the first series; no device migrations occurred in the second series.

The fixation system with screws embedded in the Digisonic SP involves a fast and simple surgical technique that seems to efficiently prevent implant migration.