39 Tympanomastoidectomy and Ossicular Chain Reconstruction Flashcards
What is a mastoidectomy? What is a tympanomastoidectomy?
What is a mastoidectomy? What is a tympanomastoidectomy?
The mastoid is a portion of the temporal bone that houses air cells connected to the middle ear space. A mastoidectomy is a surgical procedure in which mastoid bone and air cells are removed. A tympanomastoidectomy is a tympanoplasty plus mastoidectomy. This procedure is commonly used to address chronic ear disease in the mastoid bone as well as a tympanic membrane that is perforated, severely retracted, or involved with cholesteatoma.
What are the main types of mastoidectomy?
What are the main types of mastoidectomy?
There are a number of different types of mastoidectomy surgery, broadly grouped into canal wall up (CWU) and canal wall down (CWD) procedures.
- CWU mastoidectomy, the mastoid air cells are removed, leaving the posterior external auditory canal wall intact. The borders of a complete mastoidectomy are the (1) tegmen superiorly, the (2) sigmoid sinus posteriorly, and the (3) posterior canal wall anteriorly.
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CWD mastoidectomy is one in which the mastoid air cells are removed along with the posterior wall of the external auditory canal. This creates a mastoid cavity or “bowl.” With this procedure, a meatoplasty is also usually performed, which widens the opening of the outer ear canal in order to improve visualization and access to the mastoid bowl. A canal wall down mastoidectomy effectively “exteriorizes” the mastoid.
- Modified radical mastoidectomy the canal wall is taken down and the epitympanum, mastoid antrum, and external auditory canal are converted into a common cavity. The middle ear space, tympanic membrane, and ossicles are preserved. This procedure is sometimes called the Bondy modified radical mastoidectomy.
- Radical mastoidectomy, a CWD mastoidectomy is performed and the tympanic membrane and ossicles, except for the stapes, are also permanently removed. These structures are not reconstructed.
What are the indications for a mastoidectomy?
What are the indications for a mastoidectomy?
- The most common indication is chronic disease such as cholesteatoma or mastoiditis.
- Indicated for some complications of acute otitis media, such as acute mastoiditis or a subperiosteal abscess.
- A key portion of the approach for cochlear implantation or facial nerve decompression.
- Performed as part of a transmastoid approach for excision of temporal bone tumors, such as vestibular schwannoma, glomus tumor, or meningioma.
- In unusual cases, a mastoidectomy may be required for repair of a cerebrospinal fluid leak.
What are the important landmarks in mastoidectomy surgery?
What are the important landmarks in mastoidectomy surgery?
The superior border of a mastoidectomy is the tegmen, which is the thin bone layer separating the middle cranial fossa from the ear. The posterior border is the sigmoid sinus. The anterior border is the posterior wall of the EAC. The deep (medial) border is the lateral semicircular canal and incus, which are found in the aditus ad antrum, the connection between the mastoid cavity and the middle ear space. Another key landmark is the facial nerve.
When is a canal wall down procedure indicated?
When is a canal wall down procedure indicated?
A canal wall down (CWD) procedure is indicated in the following situations:
- Cholesteatoma involving the sinus tympani area, not accessible transcanal or through the facial recess
- Semicircular canal fistula with adherent cholesteatoma matrix
- The posterior canal wall is extensively damaged by disease
- The mastoid is contracted and sclerotic, preventing adequate visualization and access via a CWU approach
- Unresectable cholesteatoma matrix on the dura or posterior cranial fossa
- Attic or mastoid cholesteatoma in a patient unable to maintain follow-up or unable to safely tolerate further surgery
What are the disadvantages of a CWD mastoidectomy?
What are the disadvantages of a CWD mastoidectomy?
The mastoid bowl often fills with cerumen and requires periodic debridement* to prevent infection. Although not necessarily unsightly, the meatoplasty is often visible. *Hearing outcomes* may be slightly diminished due to the change in the acoustic properties of the ear canal. *Water restrictions are recommended due to risk of mastoid bowl infection.
What are the disadvantages of a canal wall up (CWU) procedure?
What are the disadvantages of a canal wall up (CWU) procedure?
There is a higher chance of recurrent or residual cholesteatoma, as exposure of the attic, antrum, and facial recess is more limited if the canal wall is left intact. Patients that have had a CWU procedure are more likely to require a “second look” procedure in the operating room whereas patients undergoing a CWD mastoidectomy can often be monitored in the clinic.
What is a second look procedure?
What is a second look procedure?
For patients who have had cholesteatoma removed using the CWU technique, a second look surgery may be performed several months later (typically 6 to 12 months) to determine whether there is recurrent or residual disease that was not visible at the time of the previous surgery and could not be detected on office examination.
The procedure is performed several months later to allow time for any microscopic residual disease to grow large enough to be visualized. However, one should not wait too long, as residual or recurrent cholesteatoma may grow large enough to cause damage to ear structures.
What is a facial recess approach?
What are the borders of the facial recess?
What is a facial recess approach? What are the borders of the facial recess?
The facial recess is an area within the mastoid that frequently contains air cells and is a pathway to the middle ear space. The facial recess is bordered anteriorly by the chorda tympani, posteriorly by the facial nerve, and superiorly by the incus buttress. The facial recess air cells are at the same level as the tip of the short process of the incus.
- The facial recess may be opened up to help eradicate cholesteatoma
- Also, cochlear implantation to allow introduction of the electrode through the middle ear space into the round window.
How should a lateral semicircular canal fistula be managed?
How should a lateral semicircular canal fistula be managed?
This is most often managed by performing a CWD mastoidectomy and leaving a portion of squamous matrix over the fistula. In rare cases, the cholesteatoma may be removed in its entirety and the fistula patched with a graft. Suctioning of the area should be avoided to preserve the endolymph within the canal.
What are the potential complications of a mastoidectomy?
What are the potential complications of a mastoidectomy?
Major complications include facial nerve injury, sensorineural hearing loss, cerebrospinal fluid leak, and dural venous sinus injury.
Minor complications include temporary change in taste sensation from manipulation of the chorda tympani, vertigo, and tympanic membrane perforation.
What is a Bondy atticotomy?
What is a Bondy atticotomy?
This procedure involves a limited approach to an attic cholesteatoma. An endaural incision is used and then a small atticoantrostomy is performed. The bone overlying the attic is then taken down to inferior to the level of the disease. The pars tensa and the ossicular chain are left intact.
What is an “inside-out” mastoidectomy?
What is an “inside-out” mastoidectomy?
An “inside-out” approach usually begins endaurally by raising a tympanomeatal flap and drilling an atticotomy. The mastoid air cells are drilled starting from the atticotomy and posterior canal wall, rather than starting from the mastoid cortex as with a traditional mastoidectomy. This approach can be useful when there is a very low-lying tegmen or anteriorly placed sigmoid sinus which can limit the approach for a typical atticoantrostomy.
What are the indications for an ossicular chain reconstruction?
What are the indications for an ossicular chain reconstruction?
The ossicular chain is composed of the three bones of the middle ear: the malleus, incus, and stapes. Ossicular chain reconstruction is performed when conductive hearing loss is due to a disruption or abnormality of these bones. The disruption may be due to trauma, congenital abnormalities, chronic ear disease, cholesteatoma, or surgery. Osteoclastic properties of cholesteatoma often erode the ossicular chain. Ossicular chain reconstruction is undertaken when the ear is felt to be free of disease, which is often not until a second look or subsequent procedure.
What are contraindications for an ossicular chain reconstruction?
What are contraindications for an ossicular chain reconstruction?
Acute otitis media at time of reconstruction is an absolute contraindication. Relative contraindications include persistent middle ear disease such as cholesteatoma, dehiscent facial nerve overlying the oval window, or an only hearing ear.
