12 Cochlear Implantation in Cholesteatoma Surgery


12 Cochlear Implantation in Cholesteatoma Surgery

Patients with profound hearing loss were once considered untreatable. The fitting of a cochlear implant is an innovative technique that totally changed therapeutic strategy of both congenital and acquired sensorineural hearing loss. With this device, as long as the cochlear nerve has kept its integrity, patients with acquired hearing loss have a considerable chance of improving or restoring verbal communication, and infants with congenital hearing loss subsequently may show very good linguistic development. Even though profound bilateral hearing loss is complicated with some pathology, basic requirement for the candidate of cochlear implantation stays the same.

12.1 Indications

General Indications for Cochlear Implantation

Profound (or total) bilateral hearing loss with little or insufficient benefits from conventional hearing aids in the presence of the following:

  • Good health condition.

  • Motivation to hear (adults).

  • Support from the family (children).

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.

Indications of Cochlear Implantation with Subtotal Petrosectomy in Cholesteatoma Surgery

Profound (or total) bilateral hearing loss with little or insufficient benefits from conventional hearing aids in the presence of the following:

  • Middle ear cholesteatoma.

  • Radical or canal wall down cavity with/without inflammation.

  • Petrous bone cholesteatoma with preserved cochlea and cochlear nerve.

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.

Fig. 12.1 A case of cholesteatoma with profound hearing loss in both ears. An inverted J incision is made in the temporal area to permit wide exposure of the skull for the placement of the internal unit of cochlear implant. The skin and soft tissue are opened in two layers.
Fig. 12.2 An inverted J incision is made in the temporal area, and the skin and soft tissue are opened in two layers. The opening of the skin is maintained with stiches to maximize its size.
Fig. 12.3 The external auditory canal is closed in two layers. Cartilage of the external auditory canal is removed to mobilize the skin of the cartilaginous portion. Two stitches are placed in the meatal skin to pull it out through the external auditory canal (see Chapter 11).
Fig. 12.4 Mastoidectomy is carried out to expose the inflamed canal wall down cavity. The bone near the sinodural angle should not be removed extensively to leave place for the internal unit of implantation. The sigmoid sinus is identified posteriorly, and the middle fossa plate (MFP) superiorly.
Fig. 12.5 The tympanomeatal flap is detached from the bony annulus to remove it completely.
Fig. 12.6 Bony edges in the cavity should be rounded to visualize the cavity well for cholesteatoma removal.
Fig. 12.7 Most part of the skin including cholesteatoma is removed from the middle ear after finishing the bone work. Note the wellrounded cavity. FN, facial nerve; LSC, lateral semicircular canal; MFP, middle fossa plate; SS, sigmoid sinus.
Fig. 12.8 The final piece of cholesteatoma covering the footplate is removed.
Fig. 12.9 The medial wall of the tympanic cavity is shown. The facial nerve running just superomedially to the cochleariform process is exposed posteriorly to the process. The medial wall of the tympanic cavity is covered with scar tissue. CP, cochleariform process; FN, facial nerve; TT, tensor tympani.
Fig. 12.10 The scar tissue is removed from the area of the footplate (arrow). The dissection is advanced inferiorly to expose the promontory and the round window niche. FN, facial nerve; P, promontory.
Fig. 12.11 The eustachian tube should be obliterated with periosteum before making a cochleostomy.
Fig. 12.12 Cleaning of the medial wall is completed. The footplate of the stapes and the round window niche are visualized clearly. CP, cochleariform process; FN, facial nerve; FP, footplate; JB, jugular bulb; RWN, round window niche.
Fig. 12.13 Scar tissue in the round window niche is removed. The round window membrane forming the anterosuperior wall of the niche seems to be ossified. FN, facial nerve; FP, footplate; RWN, round window niche.
Fig. 12.14 Preparation of the cochlear implantation should be completed just before opening the cochlea. A dummy of the internal unit is used to create a bet to accommodate it properly.
Fig. 12.15 A bed for the internal unit is created behind the inflamed cavity. A groove for the electrode connecting the bed and the cavity is seen (arrow).
Fig. 12.16 Holes for stay sutures have been created around the bed using small burrs. After placing the internal unit in appropriate position, a nonabsorbable surgical thread is used to fix it. An inflamed cavity is seen anteriorly to the internal unit.
Fig. 12.17 The roof of the round window niche is drilled to see clearly the round window membrane.
Fig. 12.18 The ossified round window niche is shown.
Fig. 12.19 Further drilling over the area of the round window opens the scala tympani of the basal turn.
Fig. 12.20 An electrode array is introduced into the cochlea. The eustachian tube should be closed (arrow) with periosteum before making cochleostomy.
Fig. 12.21 The cochleostomy is closed, and the electrode array is stabilized with pieces of periosteum. The cavity is packed with abdominal fat.
Fig. 12.22 The electrode is fixed to the cortical bone with bone wax.

Only gold members can continue reading. Log In or Register to continue

May 12, 2020 | Posted by in OTOLARYNGOLOGY | Comments Off on 12 Cochlear Implantation in Cholesteatoma Surgery
Premium Wordpress Themes by UFO Themes