The temporalis muscle is dissected superiorly from the dural line so that the root of the zygoma is well exposed. Here, the first cut of the drill with the largest cutting bur is made, brought back posteriorly and gently carried down so that the first landmark seen is always the level of the middle fossa tegmen. This structure will have a slight bluish to purplish hue. The rest of the mastoid dissection in the classical shape is then made, preserving the canal wall at first and establishing the degree of cellularity in the mastoid. There are two possibilities at this point. Due to lifelong eustachian dysfunction, the mastoid may be completely sclerotic with a very low-hanging middle fossa tegmen, almost touching the superior wall of the canal. If this is the case, then the canal wall is brought down as the mastoid dissection progresses, entering the antrum, which will always be present (Fig. 9-3). In this case, the wall is lowered to the level of the facial ridge (Fig. 9-4). Again, this brings up the advantage of doing the middle ear work first because one is able to see the middle ear portion of the facial nerve as one approaches the antrum. The second possibility is that the mastoid is somewhat cellular, allowing the mastoid dissection to take place, preserving carefully the integrity of the middle fossa tegmen and performing a small mas-toid dissection.
It is very rare to have a fully cellular mastoid with a cholesteatoma, although it can occur and poses a problem when taking the wall down because a large mastoid bowl has to be maintained and cleaned. So, most of the time a small cavity results when the wall is taken down for cholesteatoma. The cholesteatoma is then removed as much as possible, and, for the reasons stated earlier in the chapter, the wall is then taken down. A double-action biting forceps is used, and then with a smaller drill the wall is lowered
completely to the level of the facial ridge. It is important not to leave any sort of "step" between the level of the middle ear and the mastoid. It is very essential not to drill out nondeveloped parts of the mastoid, because there is no disease present, and
FIGURE 9—4 Facial ridge is lowered.
because it adds to the size of the mastoid and scope of the mastoid maintenance that has to be carried on for the rest of the patient's life. I prefer not to obliterate mastoids but to leave them open, lower the wall to a safe level, polish the mastoid cavity, and then, finally, cover all exposed bone with fascia, even returning to the upper part of the postauricular incision to obtain more fascia if needed.
The middle ear, in my practice, is always reconstructed (Fig. 9—5). Over the years, transposed incus grafts have been used, followed by plasti-pore, then by hydroxyapatite. Currently in my practice, I use exclusively the Kurz prosthesis interposed between the footplate in the absence of a stapes superstructure or on the stapes head to the new eardrum or to the malleus, depending on the anatomic relationships. Banked homograft rib graft cartilage or autograft tragal cartilage is interposed between the Kurz prosthesis and stapes. I do not use silastic or Gelfoam in the middle ear. I graft the middle ear with a medially laid piece of fascia brought out over to completely line the exposed bone (Fig. 9—6). Then, silastic is introduced over the eardrum and fascia. A meatoplasty is then performed and the ear is packed with gauze containing Cortisporin ointment. The incision is closed with interrupted buried catgut sutures. A pressure dressing is applied, and the patient is discharged from the hospital either that day or the next morning.
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