11 Obliteration of the Middle Ear (Subtotal Petrosectomy) in Cholesteatoma Surgery



10.1055/b-0039-169415

11 Obliteration of the Middle Ear (Subtotal Petrosectomy) in Cholesteatoma Surgery



Indications




  • Cholesteatoma in dead ear.



  • Cholesteatoma with heavily infiltrated labyrinth.



  • Unilateral advanced cholesteatoma with mental retardation.



  • Canal wall down cavity with intractable inflammation with no serviceable hearing.



  • Draining ear with no serviceable hearing with multiple previous surgeries.



  • Recurrent cholesteatoma with huge mastoid aeration.



  • Extensive exposure of middle fossa dura.



  • Cholesteatoma with large meningoencephalic herniation.



  • Major tear of the dura during surgery with ample cerebrospinal fluid (CSF) leakage.



  • Cholesteatoma or canal wall down cavity with poor bilateral bone conduction necessitating cochlear implantation.


In some patients, obliteration of the middle ear (subtotal petrosectomy) using abdominal fat with blind sac closure of the external auditory canal and closure of the eustachian tube is reasonable, or even necessary.


In case of cholesteatoma in dead ear, the only concern of that ear is to avoid recurrence. If the technique is properly executed, subtotal petrosectomy is an ultimate solution to eliminate any possibility of recurrence.


Even though there is some residue of bone conduction, heavy erosion of the labyrinth makes leaving matrix on it difficult. It eventually further invaginates into labyrinth, or causes labyrinthitis to make situation more complicated. In such cases, the labyrinth is drilled and the cavity is packed with abdominal fat.


In some advanced cases of unilateral cholesteatoma with mental retardation, maintenance of the open cavity for life is impractical. In such cases, closure of the ear might be a good solution. Meticulous audiologic examination using objective measures such as auditory brainstem response (ABR) and auditory steady-state response (ASSR) is required before surgery to verify good contralateral hearing.


A chronically inflamed open cavity with nonserviceable hearing is one of the most common candidates for obliteration of the middle ear. The patient is annoyed with multiple surgical interventions, repetitive odorous otorrhea, or frequent episode of vertigo due to thermal stimulation. This technique frees the patients from such a troublesome state, reduce frequency of office visits, and eventually improves the quality of life.


The technique can be applied even in cases with intact bony canal wall if the patient still has an inflamed ear with no recovery of hearing after multiple ear surgery.


In some advanced cases of recurrent cholesteatoma with huge pneumatization, achievement of a trouble-free canal wall down cavity using partial obliteration technique with bone paste and/or vascularized flaps is not practical. In such cases, obliteration of the middle ear can be one of the therapeutic choice, depending on contralateral hearing and the patient’s age.


Cholesteatomas with unmanageable exposure of the dura, and presence of a large labyrinthine fistula with no possibility of good hearing are other indications for subtotal petrosectomy.


A CSF leakage from a tear of the dura may occur as a surgical complication. If the leak is severe, obliteration of the cavity after repairing the dural defect with either fascia or piece of muscle is indicated. To reduce the risk of possibly lethal meningitis, air cells are intensively removed to eliminate possible pathway for CSF.


In the majority of large meningoencephalic herniation with cholesteatoma can be treated with combined extradural middle fossa and transmastoid approach. However, in some cases of very large meningoencephalic herniation reconstruction of the bone erosion is impractical, and obliteration of the middle ear after reducing the herniation and dissecting the cholesteatoma matrix is a safer choice.


The obliteration technique is also applied to cochlear implants in some special situations of cholesteatoma surgery (see Chapter 12).


In the obliterating procedure, it is very important to remove all squamous epithelium within the cavity by carrying out meticulous dissection and correct drilling techniques. However, especially in cases of cholesteatoma with thin matrix covering the dura, remnant of such epithelium may eventually form residual cholesteatoma, and radiologic follow-up of the obliterated cavity with magnetic resonance imaging (MRI) using fat suppression and diffusion sequences is mandatory.



11.1 Surgical Steps to Close the External Auditory Canal




  1. After the wide retroauricular incision that extends superior and inferior more anteriorly for better access and possibility to reflect the pinna, the external ear canal is identified (▶Fig. 11.1).



  2. The skin of the lateral part of the external ear canal is then circumferentially elevated for the width of about 1 cm. For elevation of the skin the microscope or loop glasses can be used for better visualization (▶Fig. 11.2).



  3. The external ear canal is now transected. Transection should not be performed too medially as the skin is thinner here, making dissection of the lateral part more difficult (▶Fig. 11.3).



  4. Now also the anterior part of the external ear canal is transected (▶Fig. 11.4).



  5. Anteriorly, the skin is loosened from the tragal cartilage using blunt scissors (▶Fig. 11.5).



  6. The skin of the lateral part of the external meatus is circumferentially loosened for about the width of 1 cm (▶Fig. 11.6).



  7. The skin of the external auditory canal is reflected laterally through the meatus to be sutured using resorbable surgical threads (4–0 Vicril; ▶Fig. 11.7).



  8. The closure of the second layer of the blind sac is performed using either tragal cartilage or an anteriorly pedicled subcutaneous flap (▶Fig. 11.8, ▶Fig. 11.9).

Fig. 11.1 A wide retroauricular C-shaped incision is performed.
Fig. 11.2 Elevation of the lateral part of the external ear canal.
Fig. 11.3 Transection of the external ear canal.
Fig. 11.4 Transection of the anterior wall of the external ear canal.
Fig. 11.5 Dissection of the anterior meatal skin from the tragal cartilage.
Fig. 11.6 The skin of the lateral part of the external meatus is circum ferentially loosened.
Fig. 11.7 The skin of the external auditory canal is reflected laterally through the meatus and sutured.
Fig. 11.8 Closure of the second layer of the blind sac is started.


Case 11.1 (Right Ear): Blind Sac Closure of External Auditory Canal


See ▶Fig. 11.10, ▶Fig. 11.11, ▶Fig. 11.12, ▶Fig. 11.13, ▶Fig. 11.14, ▶Fig. 11.15, ▶Fig. 11.16.

Fig. 11.9 The second layer of the blind sac is completely closed.
Fig. 11.10 After a wide retroauricular incision that covers whole external auditory canal for sufficient mobilization of the auricle, the skin and cartilage of the external auditory canal are transected circumferentially. The transection should be performed more laterally compared with usual middle ear surgery to make dissection of the lateral part easier. Note that the auricle is fully reflected anteriorly with skin hooks for the following procedures. EAC, external auditory canal.
Fig. 11.11 The tragal cartilage is detached from the anterior wall of the bony meatus. The skin of the lateral part of the external meatus is then circumferentially dissected from surrounding tissue for about 1 cm. The cartilage and subcutaneous soft tissue are used for the second layer of the blind-sac closure. For precise dissection, use of microscope is recommended. TC, tragal cartilage.
Fig. 11.12 The skin is loosened circumferentially and then everted laterally. A stitch placed on the medial end of this skin may be used to pull out to it to the external surface.
Fig. 11.13 The skin of the external auditory canal reflected laterally through the meatus is shown.
Fig. 11.14 Resorbable threads (4–0 Vicryl) are used in the external suture or the meatal skin. The everted tissue will shrink after some time and not be as visible as in this picture.
Fig. 11.15 Tragal cartilage (C) or an anteriorly pedicled subcutaneous flap dissected at the beginning of the procedure is used for the second layer of the blind-sac closure. The posterior flap is attached to the posterior rim of cartilage of the auricle. ES, internal surface of the everted skin.
Fig. 11.16 The blind-sac closure on the external auditory canal in two layers is completed.


Case 11.2 (Right Ear)


See ▶Fig. 11.17, ▶Fig. 11.18, ▶Fig. 11.19, ▶Fig. 11.20, ▶Fig. 11.21, ▶Fig. 11.22, ▶Fig. 11.23, ▶Fig. 11.24, ▶Fig. 11.25, ▶Fig. 11.26, ▶Fig. 11.27, ▶Fig. 11.28, ▶Fig. 11.29, ▶Fig. 11.30.

Fig. 11.17 A case of cholesteatoma in a contracted mastoid with large fistula in lateral and superior semicircular canals. As seen in the CT, cholesteatoma erodes the lateral semicircular canal extensively (yellow arrow). The T2-weighted image of MRI indicates decreased signal intensity of the canal (white arrow), implying some scarring process in the canal. In spite of such change, the bone conduction remains near normal.
Fig. 11.18 The meatus is entered via retroauricular incision. The tympanic membrane is retracted, making the handle of the malleus prominent. Cholesteatoma is entered from the posterosuperior quadrant of the tympanic membrane (arrow).
Fig. 11.19 To make maximal access to the middle ear, canal wall down mastoidectomy should be started in such way that the middle fossa plate (MFP) and the sigmoid sinus (SS) is identified first, and all sharp edges are removed. The drilling should gradually be advanced medially maintaining this wide access.
Fig. 11.20 The cholesteatoma filling poorly pneumatized mastoid is exposed. MFP, middle fossa plate; SS, sigmoid sinus.
Fig. 11.21 Removal of cholesteatoma consists of evacuation of debris, careful dissection of matrix from the bone, and drilling of bone that covers cholesteatoma. Suspicious area of leaving matrix for infiltration should also be drilled.
Fig. 11.22 Dissection of the matrix covering the lateral semicircular canal revealed scar tissue filling the canal (white arrow) as suspected in preoperative MRI. Note that the tympanic segment of the facial nerve is exposed extensively. The nerve runs just superomedially to the cochleariform process. CP, cochleariform process; FN, facial nerve.
Fig. 11.23 Dissection of the matrix covering the lateral semicircular canal is advanced anteriorly. The scar tissue ends at the ampulla, and invagination of the matrix into the ampulla is identified. The tympanic membrane totally adherent to the medial wall is seen. FN, facial nerve; TM, tympanic membrane.
Fig. 11.24 Cholesteatoma is removed from the labyrinth. The ampulla of the lateral semicircular canal is filled with scar tissue (yellow arrow). A blue line of the ampulla of the superior semicircular canal (black arrow) can be identified superiorly to the opening. FN, facial nerve; TM, tympanic membrane.
Fig. 11.25 The cholesteatoma covering the area of the stapes (arrow) is removed. The superstructure is totally eroded. Fistulae of superior and lateral semicircular canals are seen superiorly to the facial nerve. Ch, cholesteatoma; FN, facial nerve.
Fig. 11.26 The cholesteatoma is eradicated from the middle ear. CP, cochleariform process; ET, eustachian tube; FN, facial nerve; OW, oval window.
Fig. 11.27 Considering the patient’sold age and the wish to make this ear trouble-free, obliteration of the cavity is indicated. As a first step of closure of the eustachian tube, a piece of cartilage is pushed into the tube.
Fig. 11.28 The area of fistulae is covered with a piece of temporalis fascia. CP, cochleariform process; F, temporalis fascia; FN, facial nerve.
Fig. 11.29 The fistula is further covered with the other piece of fascia. Perichondrium is used to further close the eustachian tube, and the cavity is packed with abdominal fat.
Fig. 11.30 The coronal section of postoperative CT shows that the middle fossa plate is sufficiently thinned. The cavity is filled with abdominal fat. A large fistula is identified in the lateral semicircular canal (arrow). IAC, internal auditory canal; JB, jugular bulb;V, vestibule.


Case 11.3 (Right Ear)


See ▶Fig. 11.31, ▶Fig. 11.32, ▶Fig. 11.33, ▶Fig. 11.34, ▶Fig. 11.35, ▶Fig. 11.36, ▶Fig. 11.37, ▶Fig. 11.38, ▶Fig. 11.39, ▶Fig. 11.40, ▶Fig. 11.41, ▶Fig. 11.42.

Fig. 11.31 A case of acquired cholesteatoma with severe erosion of the labyrinth. Canal wall down mastoidectomy is carried out to expose cholesteatoma entering the middle ear from the pars flaccida (arrow) and filling the attic and the antrum. The tympanomeatal flap is protected by an aluminum sheeting. Ch, cholesteatoma.
Fig. 11.32 The tympanic cavity is entered by reflecting the tympanomeatal flap anteriorly and holding it with an aluminum sheeting. The inferior pole of cholesteatoma only reaches the level of the facial nerve, and obliteration of the cavity is not decided at this moment.
Fig. 11.33 The cholesteatoma filling the attic is partially removed to uncover newly formed bone (arrow) over the cholesteatoma infiltrating the medial wall. The bone should be removed with great care, since the uncovered facial nerve is in vicinity. Ch, cholesteatoma; FN, facial nerve.
Fig. 11.34 The newly formed bone is removed with a curette, and dissection of the matrix is carried out from posterior to anterior, along the exposed facial nerve. Cottonoid is applied to control bleeding. Note that the tympanic segment of the facial nerve is exposed extensively. Cot, cottonoid; FN, facial nerve.
Fig. 11.35 A large labyrinthine fistula is identified in the lateral semicircular canal (arrow). The cholesteatoma infiltrates the cells in the medial wall of the attic, and goes medially to the facial nerve. FN, facial nerve.
Fig. 11.36 The cholesteatoma infiltrating the medial wall of the attic is dissected from the medial face of the facial nerve. FN, facial nerve.
Fig. 11.37 The cholesteatoma is dissected form the facial nerve, but still remains in the cells located posteriorly (arrow). A small part of cholesteatoma going posteriorly toward the superior semicircular canal is indicated by an arrow. FN, facial nerve.
Fig. 11.38 Since the cholesteatoma erodes the superior semicircular canal and invaginates into the ampulla of the superior semicircular canal (arrow), labyrinthectomy is carried out. Three semicircular canals opened are seen. FN, facial nerve; LSC, lateral semicircular canal; PSC, posterior semicircular canal; SSC, superior semicircular canal.
Fig. 11.39 The cholesteatoma is dissected from the ampulla of the superior semicircular canal.
Fig. 11.40 The cholesteatoma is eradicated from the middle ear. LSC, lateral semicircular canal; PSC, posterior semicircular canal; SSC, superior semicircular canal.
Fig. 11.41 All the semicircular canals are drilled, and the vestibule is opened to remove saccule and utricle. Closure of the eustachian tube and obliteration of the cavity with abdominal fat follow. CC, common crus; ET, eustachian tube; FN, facial nerve; P, promontory; V, vestibule.
Fig. 11.42 The eustachian tube is closed with pieces of cartilage and periosteum. Packing of the cavity with abdominal fat follows. FN, facial nerve.


Case 11.4 (Right Ear)


See ▶Fig. 11.43, ▶Fig. 11.44, ▶Fig. 11.45, ▶Fig. 11.46, ▶Fig. 11.47, ▶Fig. 11.48, ▶Fig. 11.49, ▶Fig. 11.50, ▶Fig. 11.51, ▶Fig. 11.52, ▶Fig. 11.53, ▶Fig. 11.54, ▶Fig. 11.55.

Fig. 11.43 The patient underwent middle ear surgery in childhood. Immediate hearing loss followed the surgery, and the patient has never been followed up for tens of years. Hearing examination revealed unmeasurable bone conduction. The preoperative CT shows formation of huge cholesteatoma eroding not only semicircular canals but also the vestibule (arrow). Ch, cholesteatoma; V, vestibule.
Fig. 11.44 The more caudal section shows extensive exposure of the posterior fossa dura and the sigmoid sinus. The facial nerve (arrow) is completely surrounded by cholesteatoma at this level. Ch, cholesteatoma; PF, posterior fossa; SS, sigmoid sinus.
Fig. 11.45 Surface of the mastoid is exposed through retroauricular incision. Cholesteatoma filled with debris eroding surface of the mastoid is seen. EAC, external auditory canal.
Fig. 11.46 Cholesteatoma occupying the very large defect in the mastoid is shown. Ch, cholesteatoma.
Fig. 11.47 The majority of debris is evacuated and matrix covering the cavity is visualized. EAC, external auditory canal.
Fig. 11.48 The matrix is dissected from the posterior wall of the cavity. The sigmoid sinus extensively exposed is visualized. SS, sigmoid sinus.
Fig. 11.49 The cholesteatoma is dissected from the area medially to the facial nerve (FN).
Fig. 11.50 The cholesteatoma infiltrating the labyrinth is shown. Ch, cholesteatoma; FN, facial nerve.
Fig. 11.51 Removal of cholesteatoma opened the superior semicircular canal (arrow). The lateral semicircular canal is completely eroded. Ch, cholesteatoma; FN, facial nerve.
Fig. 11.52 Removal of cholesteatoma from the posterior face of the vestibule is accomplished. An opening of the vestibule can be seen (arrow). FN, facial nerve.
Fig. 11.53 The vestibule and remnants of semicircular canals are opened to ensure total removal of cholesteatoma infiltrating the inner ear. FN, facial nerve; V, vestibule.
Fig. 11.54 The eustachian tube is closed with pieces of periosteum and bone wax, and the cavity is closed with abdominal fat.
Fig. 11.55 The postoperative CT shows sufficient removal of bone from the temporal bone. The arrow indicates the fallopian canal. PF, posterior fossa; SS, sigmoid sinus.

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May 12, 2020 | Posted by in OTOLARYNGOLOGY | Comments Off on 11 Obliteration of the Middle Ear (Subtotal Petrosectomy) in Cholesteatoma Surgery
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