Closed Mastoido-Epitympanectomy with Tympanoplasty 北京大学第三医院耳鼻咽喉科 马芙蓉

Surgical Technique The closed mastoido-epitympanectomy with tympanoplasty is a tympanomastoidectomy in which particular emphasis is applied to the work in the attic. A closed MET includes mastoidectomy, and tympanoplasty.

Surgical Steps The first surgical steps of intact canal MET are similar to those of retroauricular tympanoplasty. Retroauricular skin incision Raising of periosteal flap Canal incision Exposure of external auditory canal and mastoid Elevation of meatal skin flap Canalplasty

Surgical Highlights General anesthesia Retroauricular skin incision Meatal skin flap Canalplasty Middle ear inspection Mastoidectomy Epitympanectomy Posterior tympanotomy Complete removal of cholesteatoma matrix Tympanoplasty

Surgical site after canalplasty All bony overhang has been eliminated. The shape of the canal is that of an inverted truncated cone. A correct canalplasty facilitates tympanic membrane grafting, speeds up healing, ensures the self-cleansing property of the external canal, and makes it easier to carry out second-stage tympanoplasty. Surgical site after canalplasty

The tympanomeatal flap is raised and the extent of cholesteatoma invasion of the middle ear assessed. The decision to perform a closed cavity is made on the basis of: (1)no evidence of Eustachian tube dysfunction,(2) good pneumatization of the tympanomastoid cleft, and (3) limited extension of cholesteatoma. Middle ear inspection

Division of the incudostapedial joint This step is necessary to avoid inducing a sensorineural hearing loss when working along the incusand malleus in the attic. In most instances, the long process of the incus is already eroded by the cholesteatoma so that division of the incudostapedial joint is superfluous. Division of the incudostapedial joint

Mastoidectomy

Mastoidectomy: exposure of mastoid plane The mastoid plane is exposed with two articulated retractors supplemented bt a third rigid retracor placed between the temporalis muscle and mastoid tip. Mastoidectomy: exposure of mastoid plane

Mastoidectomy: identification of antrum The antrum is identified at the intersection of two grooves formed by removing bone along the superior and posterior canal wall. The entrance of the bony external canal sbould not be lowered when drilled for the antrum. This is why the canalplasty should be completed before looking for the antrum. The middle fossa dura and sigmoid sinus are skeletonized at this stage when working in a sclerotic mastoid. Mastoidectomy: identification of antrum

Mastoidectomy: correct bone removal a: The posterior canal wall should not be lowered during canalplasty and mastoidectomy. b: Lowering the posterior entrance of the canal carries the risk of squamous epithelium ingrowth from the external canal into the mastoid the mastoid ( meatomastoid fistula ). Mastoidectomy: correct bone removal

Mastoidectomy(cont.): danger of incorrect bone removal Schematic cross section through the ear showing the correct(a) and incorrect (b) shaping of the posterior canal wall. Note that the posterior limb of the endaural incision must be made lower than the lateral entrance of the external canal and hoe the mastoid periosteal flap is rotated against the posterior canal wall to prevent atrophy of the bone and a meatomastoid fistula. Mastoidectomy(cont.): danger of incorrect bone removal

Mastoidectomy(cont.): danger of incorrect bone removal Schematic cross section through the ear showing the correct(a) and incorrect (b) shaping of the posterior canal wall. Note that the posterior limb of the endaural incision must be made lower than the lateral entrance of the external canal and hoe the mastoid periosteal flap is rotated against the posterior canal wall to prevent atrophy of the bone and a meatomastoid fistula. Mastoidectomy(cont.): danger of incorrect bone removal

Surgical site after mastoidectomy The broken lines show the position of the antrum. The digastric ridge and the stylomastoid periosteum are exposed to identify the stylomastoid foramen. The course of the mastoid segment of the fallopian canal is identified through the bone using EMG monitoring of the facial muscles (NIM-2). The retrofacial cells are exenterated. The sigmoid sinus and the middle cranial fossa dura are skeletonized. Surgical site after mastoidectomy

Epitympanectomy: exposure of the attic The lateral wall of the attic is removed with a diamond burr. The cholesteatoma fills the epitympanum. The matrix is opened with small tympanoplasty scissors, and the contents of the cholesteatoma sac are evacuated by suction. The size of the cholesteatoma is reduced to allow easier separation of the matrix from the surrounding bone. Epitympanectomy: exposure of the attic

Epitympanectomy:identification of tympanic facial nerve. The atropgic incus is removed. The cholesteatoma matrix is elevated from the lateral semicircular canal. The tympanic facial nerve is identified along the inferior margin of the lateral semicircular canal. Only on rare occasions, does an extremely large cholesteatoma prevent adequate identification of the facial nerve along the lateral semicircular canal. In such a situation, it is best to follow the mastoid facial nerve from the stylomastoid formen into the area where the anatomy has been distorted by the lesion. EMG monitoring of facial function(NIM-2) is essential in such a situation. Epitympanectomy:identification of tympanic facial nerve.

Management of semicircular canal fistula a: Always expect a fistula when elevating the cholesteatoma matrix from the lateral semicircular canal. Look for a fistula before removing the medial wall of the cholesteatoma sac. In the presence of a fistula,leave the covering skin until the end of the operation to avoid damaging the inner ear. Management of semicircular canal fistula

Management of semicircular canal fistula b: Remove the skin over the fistula when the bone work and the removal of the remaining matrix is completed.Use constant irrigation. The matrix covering the fistula is only removed if the exdostium is intact. This is usually possible infistulas up to 2 mm in diameter. If the perilymphatic space is open, the skin covering the fistula is replaced in its original position. Management of semicircular canal fistula

Management of semicircular canal fistula c: If the matrix has been removed, the intact endostium of the fistula is covered with bone dust ( obtained by drilling ) mixed with fibrin glue (bone paste). Management of semicircular canal fistula

Management of semicircular canal fistula d: The fistula is finally covered with fresh temporalis fascia placed over the bone paste. Management of semicircular canal fistula

Epitympanectomy(cont.):exenteration of the attic The malleus neck is divided and the head of the malleus removed.The cholesteatoma matrix is carefully detached from the walls of the epitympanum, and the size of the cholesteatoma sac is success matrix. The completely closed chorda-tensor fold is removed. The matrix lying lateral to the facial nerve is removed from the supralabyrinthine and supratubal recess.The position of the geniculum, petrosal nerve, and labyrinthine segment of the facial nerve should be known to avoid injury of a dehiscentnerve. A spontaneous dehiscence of the facial nerve may exist proximal to the geniculum. EMG monitoring of the facial muscles with the NLM-2 is very helpful in this phase of surgery to avoid causing a lesion of the facial nerve. Epitympanectomy(cont.):exenteration of the attic

Posterior tympanotomy The bone situated between the pyramidal facial nerve and the chorda tympani is drilled away along the tympani is drilled away along the tympanic segment of the fallopian canal. The resulting opening to the middle ear is the posterior tympanotomy. A lesion of the facial nerve should not occur because the posterior tympanotomy is carried out under direct visual control of the nerve and with EMG monitoring of the facial muscles(NLM-2). The size of the tympanotomy depends on the extent of the cholesteatoma in the facial recess and sinus tympani. A wide exposure of the sinus tympani requires sacrifice of the chorda. If the cholesteatoma is limited to the superior half of the matrix can be accomplished at this stage, working from both sides of the intact canal wall (combined approach). Posterior tympanotomy

Posterior tympanotomy:removal of cholesteatoma from the oval window Matrix covering the stapes and oval window is removed aftercompletion of all bone work because uncontrolled suction irrigation might damage the exposed inner ear.

Posterior tympanotomy:removal of cholesteatoma from the oval window A: The last portion of cholesteatoma invading the oval window niche between the stapes arch and facial nerve is exposed. Posterior tympanotomy:removal of cholesteatoma from the oval window

Posterior tympanotomy:removal of cholesteatoma from the oval window B: The removal of the matrix from the oval window begins anteriorly where the footplate ( or membrane covering the oval window ) is best identified. For the elevation of matrix from the oval window,the same precautions should be taken as when working over a fistula of the lateral semicircular. Posterior tympanotomy:removal of cholesteatoma from the oval window

Posterior tympanotomy:removal of cholesteatoma from the oval window C: The posterior matrix is best removed through the transcanal approach. Drilling a small notch in the posterior canal wall may be necessary to visualize the posterior footplate. Removal of matrix from the stapes is performed in a posteroanterior direction, taking advantage of the stability offered by the stapedial tendon. Posterior tympanotomy:removal of cholesteatoma from the oval window

Posterior tympanotomy:removal of cholesteatoma from the oval window D: The matrix has been completely removed from the oval window niche and stapes. The notch in the posterior canal wall will be reconstructed later on with preserved septal or tragal cartilage. Cutting the stapes arch with crurotomy scissors to remove matrix surrounding the stapes arch is rarely necessary. Manipulations around the stapes arch require caution to avoid luxation of the footplate. Posterior tympanotomy:removal of cholesteatoma from the oval window

Surgical site following completion of closed tympanomastoidectomy The supralabyrinthine and supratubal recesses are exenterated. Good knowledge of the anatomy of the tympanic and labyrinthine segment of the facial nerve is necessary for this purpose. Keep in mind the acute angle formed by the lateral tympanic segment. Note that the chorda-tensor fold was removed to provide adequate ventilation of the anterior attic(arrow). Surgical site following completion of closed tympanomastoidectomy

Primary reconstruction of the ossicular chain is possible in this case because the stapes, the malleus handle, the tensor tympani tendon, and the pars tensa of the tympanic membrane are intact. A modified Ionomer incus is interposed between the stapes head and malleus handle. If the malleus handle is missing, the reconstruction of the ossicular chain is carried out at a second stage. Tympanoplasty

Packing and transmastoid drain Schematic representation of packing and transmastoid drain in closed mastoido-epitympanectomy with tympanoplasty. For the sake of demonstration, a different ossicular situation from that of Fig.80 Pis illustrated. The malleus handle and the stapes arch are missing. Silastic sheeting was introduced into the tympanic cavity and Eustachian tube because of the defective middle ear mucosa. Septal cartilage is used to reconstruct the posterior canal wall. An anterior underlay of temporalis fascia was used to reconstruct the tympanic membrane.Gelfoam pledgets impregnated with Otosporin keep the meatal skin and the underlaid fascia in position over the tympanic sulcus. The external canal is packed with a strip of gauze impregnated with antibiotic mintment (Terracortril). The concha is covered by a large gauze. A conventional pressure dressing is applied over the wound. Packing and transmastoid drain

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