Classification
10.2.1 Congenital Cholesteatoma
Cholesteatoma is categorized as congenital, primary acquired, and secondary acquired. Congenital cholesteatoma is a true inclusion epidermoid incorporated into the temporal bone during embryonic development. The original cell rests do not always originate in the middle ear and can be located anywhere in the temporal bone. Often these lesions are located in the anterosuperior mesotympanum, presenting initially as a white mass behind an intact drum and subsequently with conductive hearing loss. Progression can be rapid and extensive throughout the ear, the temporal bone, and the mastoid.
10.2.2 Primary Acquired Cholesteatoma
This refers to a lesion arising in the attic or posterosuperior part of the middle ear where there has been no previous history of otitis media. In the early stage, the disease is silent ( ▶ Fig. 10.1), but when the keratin becomes moist and infected, the erosive properties of the cholesteatoma become active.
Fig. 10.1 Primary acquired attic cholesteatoma of right ear, presents with dry crust in attic.
10.2.3 Secondary Acquired Cholesteatoma
Secondary acquired cholesteatoma follows active middle ear infection usually with large posterior marginal defects and may present earlier because of an offensive smelling discharge.
10.2.4 Presentation, Early Management, and Imaging
The clinical presentations of cholesteatoma are otorrhea and conductive deafness. 1 The diagnosis is confirmed by otoscopy, supplemented by microscopy, as needed, when the presence of keratin or matrix ingress is seen ( ▶ Fig. 10.2). A pure-tone audiogram (PTA) with masking as appropriate to the findings is an essential baseline investigation in a child with a cholesteatoma. In children too young for a PTA or in children with comorbidity that makes PTA unsuitable, an accurate audiological assessment of hearing thresholds under the supervision of an experienced audiologist is mandatory before embarking on surgery. Definitive treatment is surgical but initial management includes medical treatment often with antibiotic–steroid eardrops and microsuction (Box 10.1). This aural toilet will allow better assessment of the disease and in the short term helps control the secondary infections.
Box 10.1 Management of Pediatric Cholesteatomas
Microscope and otoendoscope assessment.
Preoperative air and bone PTA.
Preoperative computed tomography (CT) scan of ears.
Definitive surgery (closed or open).
Fig. 10.2 Infected erosive attic cholesteatoma; right ear.
A CT scan is recommended to identify the extent of the soft-tissue disease, the amount of pneumatization of the mastoid, and whether there is any bone erosion over the labyrinth. A fistula of the lateral semicircular canal is the most common such finding. The scan will allow planning of the best surgical approach for the disease. It will also assist in diagnosis when this is unclear as erosion of the scutum and the distribution of the soft tissue in the attic and antrum may all help to indicate likely cholesteatoma disease. The advantage CT scanning has in children is that images are acquired quickly, so a general anesthetic (GA) is often not required. Magnetic resonance imaging (MRI) scanning more often needs a GA and gives no fine anatomical detail of the mastoid and middle ear, so while diffusion-weighted (DW) scans can confirm keratin, they have a very limited place in preoperative assessment.
10.3 Treatment of Cholesteatoma
10.3.1 Aim of Treatment
The definitive treatment for all childhood cholesteatomas is surgical.
If left untreated, an ear with cholesteatoma will lead to progressive adjacent bone destruction risking sensorineural deafness, dizziness, facial nerve palsy, and intracranial spread with meningitis, lateral sinus thrombosis, extradural collections, and cerebral or cerebellar abscesses. The hearing will inevitably deteriorate. The untreated ear will continue to discharge offensively from time to time even if these more serious complications do not occur. The risk of serious intracranial complication from untreated cholesteatoma is very significant. In one adult retrospective study, 2 nearly 7.5% of patients suffering from chronic middle ear disease with cholesteatoma developed intracranial complications. The most frequent complication was meningitis, and the average duration of the disease was 11.9 years. If the risks were divided equally over time (which is unlikely), this equates to a 0.6% risk per annum.
The goal of surgery is to remove all the cholesteatoma matrix from the middle ear and mastoid air cells while retaining or improving hearing, preserving facial nerve function, and, if possible, the chorda tympani nerve.
The aim is to provide a safe dry ear, free of infections and with useful hearing. If possible, good natural ventilation of the middle ear cleft and prevention of future progression of disease should be sought as well.
10.3.2 Choice of Approach
There are two principal approaches to surgery for cholesteatoma:
Canal wall up (CWU) or closed cavity surgery in which the posterior canal wall is left intact.
Canal wall down (CWD) or open cavity surgery in which the canal wall is sacrificed to improve access and to permit a better view during follow-up.
There are advantages and disadvantages of both the closed and open cavity techniques 3; these are summarized in ▶ Table 10.1. The big advantage of CWU or closed surgery is that a dry and self-cleaning ear is readily achieved. However, it is technically more difficult to remove the matrix completely and both residual disease and a recurrence of a new cholesteatoma from re-retraction means that further surgeries are likely to be needed. Typically, the author would plan a second-look revision tympanomastoidectomy at approximately 18 months after the first-stage combined-approach tympanoplasty (CAT) operation for an extensive cholesteatoma. The disadvantage of the open technique remains the greater likelihood of infections and the difficulty of repeated clinic visits and microsuction treatment of a child’s ear in the clinic setting.
Ideally, the surgeon should be comfortable performing all available techniques and tailor the operation to the individual’s needs.
A preoperative CT scan can provide invaluable information in planning surgery.
The author’s preference in all cases with a well or moderately pneumatized mastoid bone is to employ a postaural approach and attempt a CWU ( CAT) tympanomastoidectomy. If, however, the CT scan demonstrates a very small poorly pneumatized sclerotic mastoid bone, or an unusually low middle fossa dura or anterior sigmoid sinus, then an “inside-out” CWD atticoantrostomy operation is selected. As a rule of thumb, the distance from the posterior canal wall to the sigmoid sinus should be at least a little wider than the ear canal diameter to allow adequate access for combined-approach surgery. The surgical access from the mastoid to the attic will also require evaluation as the height of the middle fossa dura is very variable and may dip so low that the CAT is not the optimal choice.
CAT closed surgery | Open cavity surgery | |
Advantages |
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Disadvantages |
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Abbreviation: CAT, combined-approach tympanoplasty. | ||
10.3.3 Surgical Technique
A CAT allows access to the middle ear through the ear canal and also from a posterior tympanotomy (facial recess approach) through mastoidectomy. The posterior ear canal wall is left in situ, so the reconstructed ear retains a normally sized, self-cleaning ear canal and normal middle ear depth. When CAT surgery is undertaken and the ossicular chain is eroded, some surgeons like to attempt ossicular reconstruction at the first-stage operation. Others feel the results are better by waiting until the second-look surgery. The author prefers the former approach since, if successful, the child hears well immediately, and with modern scanning for surveillance (vide infra), a second surgery might be avoidable.
In the CWD operation, the posterior bony canal wall is drilled away creating an open mastoid cavity. This is also termed atticoantrostomy or a modified radical mastoidectomy.
With this operation, while the cholesteatoma matrix is also fully removed, the open cavity will become lined with similar squamous epithelium.
The cartilaginous external meatus also needs to be enlarged with a meatoplasty, with the object of achieving a self-cleaning ear in which wax and desquamated epithelium may migrate outward. This is not always achievable, and the CWD mastoidectomy patient might typically require a couple of outpatient attendances per annum for aural toilet.
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