Open versus Closed Cavity Techniques

Although controversy over "open" versus "closed" cavity techniques has cooled down considerably during the last decade or two, and despite the fact that most surgeons are now willing to use either technique depending on circumstance, there are still some surgeons who favor closed techniques and others who favor open ones.3-5

The characteristics of the two techniques are illustrated in Table 37-2. It is now generally recognized and is widely accepted that there is no significant difference in the hearing results between the two techniques.5-8

Sometimes the decision whether to use a canal wall-up or canal wall-down technique can be made preoperatively. If there have been several episodes of recurrence and the patient wishes to avoid a future operation, the canal wall-down technique is chosen. For individuals unwilling or unable to be followed-up regularly and be available for a second "stage" procedure, canal wall-down is preferable. Some patients may refuse to accept a meatoplasty under any circumstances, and such individuals should be treated with closed (canal wall-up) techniques. These patients must understand that the disease can recur, and they may require multiple serial procedures.

In individuals who have known irremediable auditory tube dysfunction (on the basis of congenital anomalies or previous surgical procedures which have destroyed the eustachian tube), a canal wall-down procedure is best.3'5'9

It is generally best to reserve the decision as to how to manage the canal wall until the time of operation because intraoperative findings are frequently important in making that decision. Findings that favor a canal wall-down or an open technique include the following:

1. Involvement of the sinus tympani

2. Involvement of the medial end of the canal wall with cholesteatoma wedged laterally between the heads of the ossicles and the medial canal wall

3. Osteitis or irremovable cholesteatoma in the pro-tubal area or hypotympanum, which generally calls for a true radical mastoidectomy

4. Substantial destruction of the canal wall, with small defects in the canal wall readily repaired (however, if the defect is large, the better part of valor may be to remove it com-pletely3)

5. The presence of labyrinthine fistula,5,10 especially if the labyrinthine fistula is large and one wishes to leave the matrix down (it is not possible to leave the cholesteatoma matrix down and perform a closed or canal wall up technique5).

More important than the technique actually chosen is how well the operation is performed. The requirements for a

TABLE 37-2

"Open" versus "Closed" Cavity Techniques

TABLE 37-2

Closed Cavity

Open Cavity

1.

Normal appearance

1.

Enlarged meatus

2.

Easy-to-fit hearing aid

2.

Difficulty to fit hearing aid

3.

No routine cleaning required

3.

Annual or semiannual canal cleaning needed

4.

Relatively high rate of recurrent

4.

Low rate of persistent or recurrent

or persistent cholesteatoma

cholesteatoma

5.

High tolerance for water exposure

5.

Occasional problem with water exposure

6.

Usually staged

6.

Usually single procedure

TABLE 37-3

Creation of a Well-Functioning Open Cavity

1. Remove all air cells, including those within the retrofacial, retrolabyrinthine, and subarcuate air cell tracts.

2. Remove the lateral and the posterior walls of the epitympa-num so that the tegmen mastoid and tegmen tympani are a smooth, featureless plane.

3. Amputate the mastoid tip.

4. Saucerize the lateral margins of the cavity.

5. Lower the posterior bony external auditory wall to the level of the facial nerve.

6. Exteriorize the anterior epitympanic recess by removing the "cog."

7. Enlarge the meatus (at least twice as large) by removing conchal cartilage.

8. Lower the medial end of the EAC toward the floor of the hypotympanum.

good open or closed cavity are listed in Table 37-3. Closed cavities must be followed regularly to detect recurrences. Open cavities must be followed regularly for annual or semiannual "cleaning."

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