Surgical Procedure

The surgical approach for removal of a cholesteatoma involving the hypotympanum or sinus tym-pani is similar to that used for removal of a small glomus jugulare tumor of the middle ear or drainage of a petrous apex cholesterol granuloma.16 A postauricular incision is preferred with the inferior portion carried interiorly, allowing the pinna to be retracted anteriorly and superiorly. A short tympa-nomeatal flap is created extending around the posterior canal from the short process of the malleus at the 12 o'clock position to the 4 o'clock position in a right ear and the 8 o'clock position in a left ear (Fig. 7-8), allowing elevation of the posterior and inferior annulus and drum. The tympanomeatal flap and drum, if present, are pedicled on the malleus. The anterior canal wall skin is elevated medial or lateral, depending on the surgeon's preference.

The bony canal is circumferentially enlarged and the anterior canal straightened. Using the chordae tympani nerve as a guide, the posterior canal wall is removed back to the vertical facial nerve. It is recommended that the drill should be rotating away from the stapes, clockwise in a right ear and counterclockwise in a left ear, and that strokes from inferior to superior, toward the stapes, should be

Tympanic Membrane Right And Left

FIGURE 7-9 Removal of the posterior canal wall back to the vertical facial nerve and floor of the ear canal down to the floor of the hypotympanum exposes cholesteatoma involving the round window niche and sinus tympani. Inspection of the sinus tympani with 30-degree and 70-degree endoscopes ensures the complete removal of cholesteatoma.

FIGURE 7-9 Removal of the posterior canal wall back to the vertical facial nerve and floor of the ear canal down to the floor of the hypotympanum exposes cholesteatoma involving the round window niche and sinus tympani. Inspection of the sinus tympani with 30-degree and 70-degree endoscopes ensures the complete removal of cholesteatoma.

used. The facial nerve is 1 to 2 mm posterior to the annulus at the fossa incudis and up to 10 mm posterior to the inferior annulus. The floor of the bony canal and annulus are lowered to the floor of the hypotympanum, reducing the potential for a postoperative reservoir for debris. By anterior removal of the posterior canal wall it may be possible to look directly into the sinus tympani, up to 10 mm posterior to the round window (Fig. 7-9). Blunt

Posterior Tympanic Sinus

FIGURE 7-8 (A,B) Cholesteatoma developing in the hypotympanum and sinus tympani from adhesive otitis media may be removed using a transcanal hypotympanotomy. For the hypotympanotomy, the tympanomeatal flap is extended inferior and anterior. In a right ear the flap is made circumferentially from the 4 o'clock position to the 12 o'clock position. This allows bone removal from floor of the canal and posterior canal wall.

FIGURE 7-8 (A,B) Cholesteatoma developing in the hypotympanum and sinus tympani from adhesive otitis media may be removed using a transcanal hypotympanotomy. For the hypotympanotomy, the tympanomeatal flap is extended inferior and anterior. In a right ear the flap is made circumferentially from the 4 o'clock position to the 12 o'clock position. This allows bone removal from floor of the canal and posterior canal wall.

MIDDLE EAR AND MASTOID SURGERY

Film Skin

Film Skin

Inner Ear Surgery Procedures

FIGURE 7-10 Reconstruction of the tympanic membrane is supported by absorbable film to reduce middle ear fibrosis. Should the eustachian tube fail to function properly following surgery, the lowered floor of the cavity will allow the drum to collapse, forming a smooth self-draining cavity, without pockets or reservoirs that may lead to chronic infections.

FIGURE 7-10 Reconstruction of the tympanic membrane is supported by absorbable film to reduce middle ear fibrosis. Should the eustachian tube fail to function properly following surgery, the lowered floor of the cavity will allow the drum to collapse, forming a smooth self-draining cavity, without pockets or reservoirs that may lead to chronic infections.

dissection is used to remove cholesteatoma from the middle ear, hypotympanum, and posterior tympanic sinuses. Inspection of the sinus tympani and hypo-tympanum using 30-degree and 70-degree 4-mm nasal endoscopes helps to ensure the complete removal of cholesteatoma.

After removal of cholesteatoma, the tympanic membrane and ossicular chain are reconstructed. Gelfilm or Silastic is placed over the promontory to reduce adhesions (Fig. 7-10). Unfortunately, many these patients have long-standing poor eustachian tube functioning, and frequently have collapse of the middle ear space. The resulting self-cleansing cavity looks like a mini-radical mastoid cavity, with a 30- to 40-dB conductive hearing loss.

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