12.1 Indications

In same particular case of cholesteatoma, cochlear implantation is required either in the same stage, or as a second-stage procedure to restore hearing. In contrast to cochlear implantation in normal middle ear in which the electrode array is inserted through posterior tympanotomy, the surgeon should take risk of recurrent disease into consideration. Canal wall down and radical cavities after cholesteatoma surgery force surgeon to place the lead of electrode array close to the surface if the cavity is maintained. Therefore, different strategy to avoid complications needs to be applied.

Recurrence of cholesteatoma in the implanted ear or shallow placement of electrode array in the open cavity gives risks of extrusion of the cochlear implant. If the ear gets infection, the risks of breakdown of the retroauricular skin covering the internal unit and even meningitis arise. Combination of cochlear implantation with subtotal petrosectomy with fat obliteration significantly reduce such danger, since the procedure separates the cavity from external environment and eliminates possibility of recurrent disease. In some cases of petrous bone cholesteatoma, cholesteatoma is removed with translabyrinthine approach. The labyrinthectomy leads to postoperative ossification and/or fibrosis of the cochlea, making cochlear implantation in future impossible. If the surgeon preserves the cochlea, an electrode array may be inserted in the same stage depending on its necessity.

An electrode is inserted into the scala tympani of the cochlea through either the round window or a cochleostomy created in the promontory. We prefer to use round window approach whenever possible, just because it is more natural anatomically. However, in case of cholesteatoma, the round window is often obliterated with ossification, and need of drilling on the area of the round window is frequently encountered. In addition, the basal turn of the cochlea may be ossified due to inflammatory process, requiring further drilling of the cochlea. To create a cochleostomy in appropriate position in such complicated situations, full anatomical knowledge of the middle ear and inner ear is required.

The surgeon should recognize that insertion of the electrode is just the start of cochlear implantation. Cochlear implantation is a system of therapy that comprises not only surgery but also postoperative fitting and rehabilitation that require a range of other professional skills and teamworking with audiologists, speech therapists, and electrophysiologists. Currently, devices produced by four companies are available in the market. Each device has its own advantages over others, but the indication for any particular patient is not known fully, especially cases with cholesteatoma. Experience with this new device is accumulating, and further studies are required.

12.2 Contraindications

Relative contraindications arise in the presence of active purulent infection with multiresistant microorganisms or tuberculosis. The procedure can be staged when the risk of postoperative infection is considered to be high. In such cases, subtotal petrosectomy with total eradication of the infection under antibiotic coverage is performed in the first stage. After 3 to 6 months when there is no sign of infection, the obliterated cavity is reopened to perform cochlear implantation. The same strategy is applied to cholesteatoma when the surgeon is suspicious of complete removal.

The required surgical steps are shown in cases described below. In contrast to other middle ear procedures, the surgery requires hair shaving and usually facial nerve monitoring.

Case 12.1 (Right Ear): Cochlear Implantation in Acquired Cholesteatoma

See ▶Fig. 12.1, ▶Fig. 12.2, ▶Fig. 12.3, ▶Fig. 12.4, ▶Fig. 12.5, ▶Fig. 12.6, ▶Fig. 12.7, ▶Fig. 12.8, ▶Fig. 12.9, ▶Fig. 12.10, ▶Fig. 12.11, ▶Fig. 12.12, ▶Fig. 12.13, ▶Fig. 12.14, ▶Fig. 12.15, ▶Fig. 12.16, ▶Fig. 12.17, ▶Fig. 12.18, ▶Fig. 12.19, ▶Fig. 12.20, ▶Fig. 12.21, ▶Fig. 12.22.