14    Otomastoiditis and Cochlear Implantation

Postimplantation chronic and acute middle ear and mastoid disease is dealt with in Chapter 7 and is only briefly mentioned here.

14.1 Chronic Suppurative Otitis Media

Patients with chronic suppurative otitis media (CSOM) might also become candidates for cochlear implantation after losing their sensorineural hearing due to the chronic middle ear infection, cavity infection, or cholesteatoma destruction or due to previous surgery. At the same time some CI candidates may suffer a chronic middle ear infection coincidentally without relation to the cause of their deafness. For both groups cochlear implantation would lead to hearing restoration, but the presence of the infection has been regarded as a (relative) contraindication.1–5

The most important risk for cochlear implantation in this group is recurrence of the infection, which could lead to labyrinthitis, meningitis, or extrusion of the implant.^6,7 The latter can be either extrusion of the electrode array out of the cochlea or through the tympanic membrane, or breakdown of the retroauricular skin covering the receiver-stimulator.^3,6–10

14.1.1 Preoperative Evaluation

As the different forms of CSOM can be considered as a continuum, several different options in treatment exist. Which to choose depends on the type of pathology, the patient, and the surgeon’s experience and choice. As limited treatment of chronic middle ear disease will very often have only a temporary effect, safer more radical options are favored. This should preferably be decided on before implantation, because revision surgery with radical removal of all pathology in the presence of a CI is difficult if not impossible and carries a serious risk of accidently sacrificing the CI during the procedure. Also, adequate pharmaceutical treatment is difficult once an infection is present, due to biofilm formation on the surface of the cochlear implant.11–13 For these reasons subtotal petrosectomy (SP) may be considered as the primary surgical solution because it represents the safer option, allowing CI insertion in the same stage in the majority of cases. In presence of a severe preoperative infection, even in SP the CI insertion may be delayed to a second stage to be performed after a few months. More information on SP can be found in Chapter 10.

14.1.2 Surgical Treatment

Simple perforations in the tympanic membrane with a dry, inactive middle ear can be closed using a staged procedure, starting with a tympanomastoidectomy or myringoplasty. Three months later, when the drum has proven to be still intact without signs of CSOM or otitis media with effusion (OME) the cochlear implantation can be performed using posterior tympanotomy approach.14 However, in some cases, the perforation functions as a physiologic grommet, preventing active disease (CSOM/OME). The myringoplasty (with or without mastoidectomy) could cause the CSOM to reappear and interfere with the cochlear implantation. Simple failure of the myringoplasty should also be considered. For these reasons subtotal petrosectomy and cochlear implantation (SP + CI) in one stage can be the preferred option.¹⁵

In CSOM without cholesteatoma the infection has to be eradicated. Staged surgery can be performed, with at least 3 months between tympanomastoidectomy and cochlear implantation.14 The perioperative treatment with antibiotics can be extended into these months. A preoperative culture of the external ear canal can reveal colonization with multidrug-resistant pathogens that can cause lasting infections. Good antibiotic prophylaxis based on such a culture will lower the risk of postoperative infection. In case of an active persistent infection with Pseudomonas aeruginosa or multiple resistant Staphylococcus aureus, a canal wall up tympanomastoidectomy performed under antibiotic coverage and a longer waiting time before implantation can be necessary. Alternatively, subtotal petrosectomy and CI placement can be performed in these cases, either in one stage or in a two-stage procedure.

In presence of middle ear atelectasis, staged canal wall up surgery with strengthening of the tympanic membrane using cartilage can be performed. In these cases, postoperatively a wait and watch policy is advised to allow diagnosis of any recurrence. However, in severe atelectasis, SP is the better option to prevent later development of cholesteatoma or electrode extrusion.⁸ This is even more important to consider in patients with a cleft palate, eustachian tube dysfunction, or atelectasis.⁷

In CSOM with cholesteatoma either staged canal wall up surgery, staged SP, or SP combined with CI (in one stage) can be performed.

After canal wall up surgery in a cholesteatoma case, however, a longer waiting time of 9 to 12 months is advised. Still, there is never an absolute guarantee of total eradication of disease. Residual or recurrent cholesteatoma can develop long after the 9 to 12 months waiting time. We therefore prefer SP combined with CI. An advantage of SP is the fact that it allows more radical removal of disease and thus lowers the risk of recurrence. A meticulous surgical technique may reduce the risk of residual/entrapped cholesteatoma to almost zero.^15–17 A disadvantage of SP is that the cavity becomes hidden from external inspection, with a need for radiologic follow-up to check for entrapment of cholesteatoma. SP in cholesteatoma cases can be performed in two stages when the ear is actively infected or when the surgeon is not sure of total removal of the disease.

Finally, the presence of a previous radical cavity also demands special care. Early attempts to insert a cochlear implant in an existing radical cavity (canal wall down) resulted in a high rate of complications, mainly extrusion of the array through the very thin epithelial lining of the cavity.^4,6,10,18 Also, cavities are in direct contact with the external environment and can easily and repeatedly become infected. Regular cleaning of the cavity once or twice a year at the outpatient clinic can produce damage to the epithelial lining, with a potential risk for the implant. Infections of the cavity confer a higher risk of developing labyrinthitis, meningitis, and implant extrusion. Although there are different techniques for covering the array described (using muscle or cartilage), we feel that SP with abdominal fat is the safest and most permanent solution in cases with a previous radical cavity. Alternatively, a technique with closure of the external ear canal and eustachian tube without abdominal fat obliteration is described, which can be useful in children without much fat.¹⁹ In a dry, inactive cavity SP can be performed in a single stage; in an infected cavity a staged procedure may be considered.

14.1.3 Postoperative Imaging

Follow-up with imaging might be required when there is risk of residual or recurrent cholesteatoma. The presence of a cochlear implant impedes the routine use of MRI for follow-up of cholesteatoma cases, although MRI up to 1.5 T can be used safely after application of a head bandage to fixate the implant.20,21 However, the visibility of a possible cholesteatoma on MRI will be compromised because of the presence of an 8-cm artifact (see Chapter 3). Removal of the magnet requires only two small procedures (removal and replacement) performed under local anesthesia and in sterile circumstances (in adults), but artifacts from the cochlear implant (up to 3 cm) will still be present. Moreover, both procedures may lead to infection of the surgical site and weakening of the pocket carrying the magnet, giving more risk of displacement.²¹

CT imaging is a good option for follow-up, following the patient at 1, 3, 5, and 10 years postoperatively, even though it is not the gold standard for detecting residual cholesteatoma. The capacity of CT in this situation is improved by the presence of air (in combined approach, staged surgery) or abdominal fat (in SP), both of which create an ideal interface for differentiation. Also repeated CT examinations might demonstrate the lesion to be growing and thus more suspect for cholesteatoma (see Chapter 10, Fig. 10.1 and Fig. 10.2).

14.1.4 Special Populations

Not all patients are equally vulnerable to middle ear infections. There are several groups that need more attention before planning a cochlear implantation. These groups also have a higher risk for complications or loss of the CI postoperatively. The prolonged use of antibiotics (local application using ear drops or systemically applied) can lead to fungal biofilm formation that might also need treatment.12

Risk factors for infection or extrusion

• Children under 3 years of age

• Otitis due to multiple resistant bacteria such as Staphylococcus aureus or Pseudomonas aeruginosa

• Tuberculous otitis media

• Cleft palate/eustachian tube dysfunction

• Immune deficiencies (e.g., AIDS/HIV, diabetes mellitus, chemotherapy, other)

• Radiotherapy

• Osteoradionecrosis

• Multiple skin incisions or previous wound healing problem

Multidrug-Resistant Staphylococcus aureus/Pseudomonas aeruginosa/ Other

In patients with a history of chronic otomastoiditis/otitis media or in patients with continuous use of a hearing aid, the external ear canal can be permanently colonized with these bacteria. Postoperative infections may be prevented by taking a culture of the external ear canal preoperatively and treating accordingly, starting antibiotics 1 week preoperatively.^22,23

Tuberculous Otitis Media

Tuberculous otitis media (TOM) presents a rare form of chronic otitis media and is usually only recognized late.^24,25 Specific tests for tuberculosis are not routinely performed. Although the incidence is low, only 0.05 to 0.9% of all chronic middle ear infections in developed countries, worldwide it is rising. Classic symptoms are refractory otorrhea, necrotic eardrums with granulation tissue, white exudate, and single or multiple perforations. Complications can comprise sensorineural hearing loss, fistulas, facial paralysis, labyrinthitis, osteomyelitis, and spread of infection to the central nervous system (CNS). When no reaction to antibacterial or antifungal therapy is seen, TOM has to be considered. Intensive treatment with antituberculosis therapy should be started and continued for at least 6 months.24–27 It is wise to perform cochlear implantation only after adequate treatment. Cochlear fibrosis or ossification in TOM has been reported²⁶ and seems likely to occur in part of the TOM population due to the long-lasting inflammation. Loss of sensorineural hearing in TOM patients could also be the result of the antituberculosis therapy (aminoglycosides). Interactions occur between HIV infection and tuberculosis and therefore HIV testing is recommended in patients with TOM.

Cleft Palate/Eustachian Tube Dysfunction

Due to eustachian tube dysfunction in patients with a cleft palate (or in patients with middle ear atelectasis), there is a higher risk for CSOM with development of cholesteatoma or OME. SP technique is advised.⁷

Radiotherapy

Previous radiotherapy can lead to sensorineural hearing loss but can also hamper implantation. Pathologic changes could lead to middle ear effusion, eustachian tube fibrosis, and chronic suppurative otitis media. Radiotherapy can also lead to intracochlear fibrosis and ossification,²⁸ to fibrosis and scarring of tissues in the internal auditory canal, and to obliterative endarteritis that has an influence on the vessels in the radiation field.²⁹ As the skin too can be affected (radiation dermatitis), thought should be given to a minimal incision and skin flap design.²⁹ Management of irradiated cases can be challenging, but an irradiated ear without any infection and rehabilitated with a cochlear implant should still be possible.²⁹ An SP in combination with a cochlear implant seems a reasonable solution in these rare cases, although some suggest muscle flap obliteration instead of obliteration with fat.²⁹

Osteoradionecrosis

In osteoradionecrosis the blood supply to the temporal bone is compromised, with necrosis of bone as a result. Osteoradionecrosis has been reported as a lasting source of infection,³⁰ possibly with softening of the temporal bone making facial nerve damage more likely. This pathology can be treated with local débridement, local antibiotics and hyperbaric oxygen, and sometimes surgical removal of bone sequesters is necessary. Staged surgery is advised.³⁰

14.2 Otitis Media with Effusion

In OME cases, pre as well as post cochlear implantation, ventilation tubes can be inserted. Ventilation tubes do not represent a contraindication to cochlear implantation once they are present in a dry, trouble-free ear.14,31 Checking on adenoid and tonsil hypertrophy, performing a preventive adenoidectomy, and treating allergy or chronic sinus disease are recommended in this population. The management of ventilation tubes in CI patients is not much different than in any other patient with ventilation tubes. Sometimes the tubes have been inserted in combination with ABR measurement for better diagnostics on hearing loss before the cochlear implantation.

It is advised to perform the insertion at least 2 to 6 weeks before CI surgery.³¹ Counseling of the patient or parents of a child patient needs to include the higher risk of otitis media and thus meningitis because of the presence of ventilation tubes. Also recommended is counseling of the general practitioner on these higher risks with the need for prescription of systemic antibiotics in case of middle ear disease. Children under 3 years of age are known to have a high incidence of acute otitis media: 50% have three episodes of AOM by 3 years of age and the peak occurs around 1 year.¹⁴ In patients (often children) with middle ear infections, an outpatient check 1 week before surgery is an extra safeguard for adequate preoperative management with better chances of successful surgery. Recent otorrhea, the presence of mucosal edema, and mucopurulent fluid found during surgery are considered contraindications for cochlear implantation. In pediatric CI candidates some surgeons proceed with implantation in the least affected ear to create access to hearing/speech language development, and place a ventilation tube in the contralateral ear that receives a delayed second-side implantation later. This possibility of placing only one implant, because of inflammation in the other ear, has to be included in preoperative counseling of the parents.³¹ Further counseling on the delayed second implant might be necessary; not all parents will agree with proceeding with the second implant.

Table 14.1 shows the different middle ear and mastoid infections with their management.

14.3 Postoperative Chronic Middle Ear and Mastoid Disease

In an active CSOM without presence of cholesteatoma, treatment with intravenous antibiotics is sometimes sufficient to resolve the infection, even with a CI present. In the presence of fluctuation (of fluid) around the receiver-stimulator, the site needs to be punctured and the fluid needs to be cultured, using either a needle for aspiration or a small incision in the retroauricular scar. Caution should be taken not to damage the receiver-stimulator or the electrode arrays. An additional head bandage is necessary when a void is present. In limited infections this usually solves the problem, but in more extended infections this may not be sufficient. Biofilm formation could already have started, making pharmaceutical treatment more difficult if not impossible.11 Then only explantation and reimplantation after settling of the infection (after 3–6 months) remain as a viable option.

Table 14.1 Preimplantation middle ear and mastoid pathology: management and treatment

Table 14.2 Postimplantation middle ear and mastoid pathology: management and treatment

The rate of explantation for medical reasons, including postoperative infection and implant extrusion, is around 1 to 3% for adults and 2 to 8% for children.23 Likelihoods for explantation mentioned are 1:3 in the presence of a postauricular abscess and 1:10 in otitis media.²³ Thus these postimplantation infections have to be taken very seriously. Chapter 7 presents some examples of postoperative infections and their management.

Table 14.2 shows the different postoperative middle ear infections with their management.

14.4 Acute Postoperative Middle Ear and Mastoid Infection

Finally, postimplantation acute middle ear infections with/without intratemporal or intracranial complications can also develop in a CI patient. These are also not necessarily related to the CI, but do form a serious threat for the patient and the implant. Treatment needs to be prompt and vigorous, and usually leads to explantation. See Table 14.2 and Chapter 7.

14.5 Removal of Cochlear Electrode and Use of Dummy Electrode

When a cochlear implant has to be explanted and the cochlea itself is not involved by the infection, it is best to leave the distal, intracochlear part of the electrode array in the cochlea and remove the rest of the implant. In this way the lumen of the cochlea remains patent for future re-implantation but also remains sealed off from the infection. In case of a purulent infection with extension around the electrode array or invasion of the cochlea by the infection, the electrode array needs to be removed. A dummy electrode can be inserted in the cochlea to keep the lumen patent.32 A higher risk of meningitis is present in the last situation. Antibiotic treatment is necessary perioperatively.

14.5.1 Dummy Electrode

In sporadic cases a dummy electrode is needed to keep the cochlear lumen patent, without placement of an actual cochlear implant. This could be necessary, for example, in active otomastoiditis with meningitis, where the infection is still too active for implantation, but with the need to safeguard the lumen in the cochlea for future insertion (after 3–6 months). Also in revision surgery during which the cochlear implant needs to be removed, the cochlear electrode array should be cut off and left in the cochlea. Only when there is ongoing infection in the cochlea (cochleitis) should the array be replaced with a dummy electrode to keep the lumen accessible for future insertion of a new electrode array (see Case 7.6 in Chapter 7).

A dummy electrode could also be of help in countries where the insurance and reimbursement relating to cochlear implantation takes time to organize, especially in the more acute cases.³²

Dummy electrodes (sterile nonfunctional electrodes) can be provided on request by the companies supplying the CIs: the diameter needs to be the same size as the electrode of the intended eventual cochlear implant. During the replacement, the fibrous sheath surrounding the dummy electrode can easily be recognized and the real electrode can be inserted using this same sheath to give proper access.

Case 14.1 Cochlear Implantation in a Patient with Radical Cavity Right Ear (Fig. 14.1.1–Fig. 14.1.16)

Stay updated, free articles. Join our Telegram channel

Join