10 Problems and Solutions in Middle Ear Cholesteatoma Surgery


10 Problems and Solutions in Middle Ear Cholesteatoma Surgery

10.1 Labyrinthine Fistula

In our experience, labyrinthine fistulas complicate about 10% of cholesteatomas we operated on (▶Fig. 10.1). In all cases of cholesteatoma, the presence of a labyrinthine fistula should be assumed during surgery until its absence is verified. Lack of any inner ear symptom or signs of a fistula does not mean that the labyrinth is intact. The lateral semicircular canal, located superficially in the vicinity of the attic, is the site most commonly involved (▶Fig. 10.2 ).

The choice between canal wall down or up technique, depends mainly on how far the disease has extended and the size of the mastoid (see Indications in Chapters 6 and 7). When canal wall down technique is used, it is better to leave the matrix on the fistula to avoid postoperative labyrinthitis. Therefore, according to our strategy in which the closed technique is used only in limited numbers of cases, the posterior wall is usually removed and the matrix is left in place. If the extent of the disease and the status of the mastoid allow the closed technique to be used, treatment of a labyrinthine fistula depends on its size. In many cases, the fistula is already large (> 2 mm) at the time of operation. In such cases and those with fistulas in the ear with better hearing, canal wall down techniques are indicated and the cholesteatoma matrix is left over the fistula, to avoid deaf ear (▶Fig. 10.3, ▶Fig. 10.4, ▶Fig. 10.5). In canal wall down tympanoplasty, since the fistula is exteriorized in the cavity with the matrix left in place, second-stage surgery for the fistula is not necessary.

Cholesteatoma with fistulas smaller than 2 mm may be treated with canal wall up techniques. When canal wall up technique is used, management of the fistula depends on its size. If the matrix is cut with a sufficient margin, the matrix covering the fistula is isolated from the surrounding area, and most of the cholesteatoma is dissected from the middle ear. To avoid keeping the inner ear open for a long time, further management on the fistula should be performed at the end of surgery when all the reconstructions are completed and materials to cover the fistula are available. If the fistula is less than 1 mm in size, the matrix covering the fistula can be removed. Blunt dissection of the matrix is done carefully with a microdissector and a small cottonoid under continuous suction irrigation (▶Fig. 10.6). The opening in the labyrinth (▶Fig. 10.7) should immediately be closed with bone paste, and the area covered with a piece of either temporal fascia or perichondrium (▶Fig. 10.8, ▶Fig. 10.9). If the matrix is adherent to the membranous labyrinth or the fistula is larger than 1 mm, the matrix is left in place, even in canal wall up technique. To reduce the epidermis and to interrupt its possible nutrient pathways, the matrix is trimmed with a sharp knife, leaving a small matrix that is less than 1 mm larger than the margin of the fistula. Meticulous care should be taken not to enter the labyrinth. If the labyrinth is entered, the matrix is removed and the fistula is managed as described above. If the canal wall up technique is implemented, second-stage surgery should be planned within 6 months. In our experience, the epidermis left over the fistula in closed technique disappears in 70% of cases, or in the remainder forms an easy-to-remove pearl at the second stage (▶Fig. 10.10).

In some cases, the fistulas get local inflammation that lead to closure of the semicircular canal with fibrosis. Removal of the matrix is possible in such cases even when the fistula is large. The condition can be diagnosed preoperatively with heavily T2-weighted magnetic resonance imaging (MRI). Another case of safe removal of the skin from large labyrinthine fistula is a thick coverage over it. In such condition, the surgeon can remove only the superficial part of its coverage using sharp scissors, and removal of skin without entering the labyrinth is achieved. In such cases, the area of the fistula can be covered with bone paste to reduce possibility of labyrinthitis.

Fig. 10.1 A case of cholesteatoma with labyrinthine fistulae in the right ear. In both superior (white arrow) and lateral (yellow arrow) semicircular canals, labyrinthine fistulas are clearly seen after removal of the cholesteatoma matrix.
Fig. 10.2 The commonest site for labyrinthine fistula. LSC, lateral semicircular canal.
Fig. 10.3 (a, b) Cholesteatoma matrix is dissected using a sharp knife.
Fig. 10.4 (a) Matrix is left in place. (b) Matrix is exteriorized through the fascia.
Fig. 10.5 View at the end.
Fig. 10.6 (a, b) Dissecting the cholesteatoma matrix from a small fistula.
Fig. 10.7 (a, b) View of the fistula after matrix removal.
Fig. 10.8 (a, b) The fistula is immediately covered with bone paste.
Fig. 10.9 (a, b) Fascia overlying the matrix and bone paste.
Fig. 10.10 (a, b) Removal of residual cholesteatoma during second-stage surgery.

10.2 Bone Erosion in the Tegmen

Bone erosion in the tegmen is seen frequently in cholesteatoma surgery. It may eventually cause meningoencephalic herniation (see Chapter 10.5). Patients with meningoencephalic herniation have a high risk of liquorrhea, meningitis, and epilepsy caused by an epileptogenic focus in the herniating brain tissue. Since the presence of both the erosion in the tegmen and labyrinthine fistulas usually mean progression of destructive process in the attic and the antrum, they often complicated with each other. In such cases, management of both complications simultaneously is required.

To prevent these complications, large erosions should be repaired with cartilage and bone paste, and the area covered with fascia. If a small area of the middle cranial fossa dura is exposed but not protrude into the canal wall up cavity, it can be left in place. If it is seen in the canal wall down cavity, a pedicled subcutaneous tissue flap may be harvested (from beneath the concha cartilage during the later meatoplasty) and placed over that area.

Case 10.1 (Right Ear)

See ▶Fig. 10.11, ▶Fig. 10.12, ▶Fig. 10.13, ▶Fig. 10.14.

Fig. 10.11 Management of labyrinthine fistula in the lateral semicircular canal. The majority of cholesteatoma has already been removed from the middle ear except the thickened and inflamed skin (white arrows) covering the area of fistula. The tympanic segment of the facial nerve courses just superiorly to the cochleariform process (yellow arrow).
Fig. 10.12 The skin covering the fistula is started to be dissected toward the fistula taking care not to open the inner ear.
Fig. 10.13 A small piece of skin covering the fistula is cut out, and rest of inflamed skin is removed.
Fig. 10.14 The final status of the labyrinthine fistula is shown (arrow). The fistula covered with a small piece of skin is located in a bony bulge just superiorly to the facial nerve. In reconstruction, the medial wall of the cavity is covered with pieces of fascia, leaving the area of the fistula. CP, cochleariform process; FN, facial nerve.

Case 10.2 (Right Ear)

See ▶Fig. 10.15, ▶Fig. 10.16, ▶Fig. 10.17, ▶Fig. 10.18, ▶Fig. 10.19, ▶Fig. 10.20, ▶Fig. 10.21, ▶Fig. 10.22, ▶Fig. 10.23, ▶Fig. 10.24, ▶Fig. 10.25, ▶Fig. 10.26, ▶Fig. 10.27.

Fig. 10.15 Viaretroauricular incision, the external auditory canal is entered. Granulation tissue is seen in the pars flaccida. Note the limited access to the tympanic membrane at this moment.
Fig. 10.16 The posterior wall is removed to reach the area of the tympanic membrane and to open the small antrum. Cholesteatoma in the antrum is started to be seen (arrow). The tympanic membrane is protected with an aluminum sheeting.
Fig. 10.17 Cholesteatoma filling the attic and the small mastoid is visualized. The tympanic membrane is detached from the bony annulus, and the tympanic cavity is opened. Cholesteatoma descending to the posterior mesotympanum is visualized (arrow).
Fig. 10.18 Thick mucosal sac covering cholesteatoma descending to the posterior mesotympanum is opened.
Fig. 10.19 Evacuation debris visualized the head of the stapes (arrow) under the matrix.
Fig. 10.20 The head of the malleus is cut with scissors to make access to the cholesteatoma invaginating anteriorly and medially to it.
Fig. 10.21 Cholesteatoma filling the supratubal recess is dissected.
Fig. 10.22 The small area of middle fossa dura uncovered in the tegmen of the antrum is coagulated with bipolar to eliminate risk of leaving matrix over it.
Fig. 10.23 The majority of cholesteatoma is removed from the middle ear. Once the inner ear is opened, it should be closed as soon as possible to avoid labyrinthitis. For that sake, further management of fistula is reserved for the last moment, and a small piece of inflamed skin is left over the fistula (black arrow). The facial nerve is exposed and prominently bulged (yellow arrow) just behind the cochleariform process. The stapes (white arrow) can be identified posteriorly to the bulge. CP, cochleariform process; FN, facial nerve.
Fig. 10.24 In this particular case, the surface of the thick coverage over the fistula is cut out taking care not to open the lateral semicircular canal (arrow).
Fig. 10.25 Removal of the skin covering the fistula is accomplished (arrow). Note the huge bulge of the facial nerve just behind the cochleariform process. CP, cochleariform process; FN, facial nerve.
Fig. 10.26 The temporalis fascia is grafted underlay. A plastic cut is made in the inferior meatal skin for intimate lining.
Fig. 10.27 The final shape of the cavity is shown. The small area of the middle fossa dura exposed in the tegmen is covered with bone paste. The final shape of the cavity is shown. F, fascia; TM, tympanic membrane.

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May 12, 2020 | Posted by in OTOLARYNGOLOGY | Comments Off on 10 Problems and Solutions in Middle Ear Cholesteatoma Surgery
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