A slightly dull, short sickle knife is used to make external canal incisions in the 11 and 6 o'clock positions; these incisions are joined approximately 6 mm lateral to the drum with a round knife (Fig. 15-1). Several interrupted passes with the knife are made so as to take the incision through the periosteum and cut tissue tags tethering the flap. The sickle knife crushes the edges of the flap to minimize
FIGURE 15—1 External ear canal incisions.
bleeding. It is usually possible to gradually increase the size of the speculum during this step. The final connection may be easier to make using the micro-scissors.
The speculum is fixed using a speculum holder. The holder is always used, as it assists with hemostasis, helps to secure the patient's head, provides a firm base against which to curette, and keeps both hands free to work. The canal elevator is passed firmly along the bone to elevate a tympano-meatal flap down to the annulus; every effort is made to avoid tearing the flap. The use of increased magnification helps to improve precision in this dissection and to avoid errors. The annulus is exposed along the entire width of the flap. The middle ear is entered in the posterosuperior quadrant, and a Rosen needle is used to dissect the annulus from its groove and identify the chorda tympani if it is not encased in the bone. An annulus elevator is inserted and the annulus freed from its sulcus inferiorly. Most tears occur here as the annulus is not clearly identified or as it is deeply embedded in bone. The chorda is dissected free from its fold of mucosa and then followed anterior and superiorly, medial to the malleus. The chorda is regularly moistened with gelatin foam pledgets soaked in saline during the procedure. This prevents many of the patient complaints of taste disturbance later.
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