5 Retroauricular Transcanal Approach


5 Retroauricular Transcanal Approach

According to our strategy, a transcanal approach through retroauricular incision can be used only in limited cases of cholesteatoma. To prevent recurrence of the cholesteatoma, we believe that it is important to maintain bony wall as much as possible when canal wall down technique is not used. Therefore, we do not pursue distal end of cholesteatoma by removing the posteri- or wall widely from the bony meatus. The use of this approach in our group is therefore limited only to the cases with small pars tensa cholesteatomas with minimal invagination into the attic and the facial recess, or congenital cholesteatomas mainly localized in the tympanic cavity. Since a wide external auditory canal is a prerequisite of the safe surgery, technique to carry out appropriate meatoplasty safely is of tremendous importance. The bone removed in the surgery to enlarge the approach to the cholesteatoma should be securely closed using a sufficiently large piece of cartilage. If there is a necessity to enlarge the approach, or the matrix is disrupted in invisible area from the small atticotomy, we convert the technique to canal wall up to ensure eradication of the disease under the preserved canal wall. Refer to the case presented in this chapter (see ▶Fig. 5.1, ▶Fig. 5.2, ▶Fig. 5.3, ▶Fig. 5.4, ▶Fig. 5.6, ▶Fig. 5.7, ▶Fig. 5.8, ▶Fig. 5.9, ▶Fig. 5.10, ▶Fig. 5.11, ▶Fig. 5.12, ▶Fig. 5.13, ▶Fig. 5.14, ▶Fig. 5.15, ▶Fig. 5.16, ▶Fig. 5.17). Additional cases are also shown in Chapter 8.

Case 5.1 (Right Ear)

Fig. 5.1 The axial computed tomography (CT) (a) demonstrates limited extension of the cholesteatoma to the posterosuperior part of the tympanic cavity. An erosion of the incudostapedial joint is identified (arrow), The coronal CT (b) demonstrates small extension of the cholesteatoma superiorly to the tympanic segment of the facial nerve (red arrow), but it does not surpass the short process of the incus (blue arrow).
Fig. 5.2 The meatus is entered through a retroauricular incision. A pars tensa cholesteatoma is identified in the posterosuperior quadrant of the tympanic membrane (arrow). Access to the tympanic membrane is limited by bony protrusions in the anterior and the inferior walls. SS, sigmoid sinus.
Fig. 5.3 The whole skin in the external auditory canal is detached medially, and the bony meatus is ready for canaloplasty. To save time, the largest possible burrs are used in this procedure. Since cutting burrs easily catch the tympanomeatal flap, the flap should be protected with an aluminum sheet made from the cover of surgical thread.
Fig. 5.4 Canaloplasty is on the way. In canaloplasty, never move the drill from lateral to medial. The drill should be moved from medial to lateral in the superior and the inferior walls (arrow), and parallel in the anterior and the posterior walls.
Fig. 5.5 Removal of the bony protrusion to some extent enables dissection of the meatal skin from the bone located medially to the drilled area. The drilling of the meatus is gradually advanced medially by repeating such process.
Fig. 5.6 Canaloplasty is accomplished. Note that the entire tympanic membrane has become accessible. Ch, cholesteatoma.
Fig. 5.7 The tympanic cavity is entered from inferior not to damage the matrix of cholesteatoma. The inferior pole of the cholesteatoma is visualized (black arrow). The chorda tympani nerve involved in the cholesteatoma is seen (blue arrow).
Fig. 5.8 The chorda tympani nerve is cut, and the matrix is carefully detached from the surrounding bony structures.
Fig. 5.9 The remnant of the incus covering the cholesteatoma is removed. Note the erosion of the long process. I, incus.
Fig. 5.10 Since the cholesteatoma has eroded the posterosuperior part of the bony annulus, removal of the incus visualized the superior pole of the cholesteatoma. CP, cochleariform process; FN, facial nerve; S, stapes.
Fig. 5.11 The cholesteatoma is detached from the superstructure of the stapes (arrow). FN, facial nerve.
Fig. 5.12 The cholesteatoma is eradicated from the middle ear. The matrix is completely preserved.
Fig. 5.13 The tendon of the tensor tympani muscle is cut to mobilize the medialized tympanic membrane.
Fig. 5.14 A piece of temporalis fascia is introduced into the canal.
Fig. 5.15 The fascia is grafted underlay. After partially packing the tympanic cavity with Gelfoam, a piece of thick tragal cartilage serving for reinforcement of the posterosuperior quadrant of the tympanic membrane, and simultaneously, as a columella is introduced.
Fig. 5.16 The cartilage is placed over the stapes.
Fig. 5.17 The tympanomeatal flap is replaced over the fascia, and the tympanoplasty is completed.

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May 12, 2020 | Posted by in OTOLARYNGOLOGY | Comments Off on 5 Retroauricular Transcanal Approach
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