41 Cholesteatoma Flashcards
What is a cholesteatoma?
What is a cholesteatoma?
Cholesteatomas are epidermal inclusion cysts of the temporal bone composed of squamous epithelium and associated debris. These masses enlarge over time and become destructive, commonly with surrounding inflammation and granulation tissue.
The word cholesteatoma was first used to describe its light color and gross resemblance to cholesterol crystals under microscopy. This observation turned out to be incorrect—there is no cholesterol or fat in cholesteatomas.
What are the different types of cholesteatoma?
What are the different types of cholesteatoma?
The three main types are congenital, primary acquired, and secondary acquired (Table 41-1).
Briefly describe the different pathways of formation.
Briefly describe the different pathways of formation.
Congenital cholesteatomas are thought to originate from keratinizing squamous epithelium of the middle ear cleft. Although the etiology remains unknown, multiple theories exist to describe the origin of the squamous epithelium. These theories include epidermoid cell rests within the middle ear (most favored theory), squamous metaplasia, epithelial migration through tympanic membrane (TM) microperforations, and deposition of desquamated epithelial cells from amniotic fluid.
Primary acquired cholesteatomas usually arise in the setting of retraction of the TM, usually as a result of otitis media and chronic eustachian tube dysfunction. Although usually arising from the pars flaccida, they can more rarely develop in the pars tensa. Secondary acquired cholesteatomas, alternatively, arise in the setting of TM perforations with epithelial migration. Multiple theories exist to explain the pathogenesis of acquired cholesteatomas including: TM invagination, migration of epithelium though TM perforations, basal cell hyperplasia, squamous metaplasia, and implantation.
What is the invagination theory?
What is the invagination theory?
Invagination is the most accepted theory of primary acquired cholesteatomas. TM retraction results from negative middle ear pressure due to eustachian tube dysfunction, poor pneumatization of the mastoid, inflammation, and/or TM atrophy. Progressive retraction forms a pocket resulting in disrupted normal epithelial migration and drainage of keratin debris. As this process progresses, a cholesteatoma forms.
Why treat cholesteatoma?
Why treat cholesteatoma?
Cholesteatomas have a propensity to become recurrently infected and erode bone. Once infected, eradication of an infection may be very difficult, and can result in a variety of intracranial and extracranial complications associated with chronic otitis media. The bacterial flora associated with cholesteatomas are also different from those in acute otitis media. Infections associated with cholesteatomas are frequently polymicrobial with an increase in anaerobes and antibiotic-resistant bacteria.
Bone erosion can affect various structures in the temporal bone that can result in hearing loss, vestibular dysfunction, facial nerve injury, and intracranial complications. Bone erosion is thought to be due to the influx of inflammatory mediators due to chronic inflammation and infection that results in an imbalance of bone remodeling favoring resorption.
How does a congenital cholesteatoma present?
How does a congenital cholesteatoma present?
Congenital cholesteatomas usually present as white or yellow masses in the anterior superior quadrant of the middle ear (Figure). Unlike acquired cholesteatomas, congenital cholesteatomas usually arise in the setting of an intact TM with an absence of otorrhea. Many times they are asymptomatic, and other symptoms vary depending on the extent of the disease. Presenting symptoms include slowly progressive conductive hearing loss (CHL), vertigo, facial nerve paralysis, or intracranial infection.
Figure text: Congenital cholesteatoma behind an intact tympanic membrane.
How do acquired cholesteatomas present?
How do acquired cholesteatomas present?
Acquired cholesteatomas usually present as posterior superior retraction pockets seen at the margin of the TM with surrounding keratin debris. Acquired cholesteatomas may or may not have TM perforations with persistent foul-smelling otorrhea and granulation tissue. Presenting symptoms, as in congenital cholesteatoma, vary depending on the extent of the disease and can include many of the same features mentioned in the prior paragraph.
What is the role of imaging in the preoperative assessment?
What is the role of imaging in the preoperative assessment?
Computed tomography (CT) is frequently used to augment physical examination in those suspected of having a cholesteatoma. Although not required for uncomplicated cases, CT provides valuable information regarding extent of disease, involved structures, and relevant anatomy that assists in preoperative planning. CT may also prove to be very helpful in revision cases. Magnetic resonance imaging (MRI) is less commonly used, but is helpful in evaluating intracranial complications.
What is the one CT finding commonly seen in acquired cholesteatoma that your attending likely will ask about?
What is the one CT finding commonly seen in acquired cholesteatoma that your attending likely will ask about?
Blunting or erosion of the scutum is a common finding on CT in those with cholesteatoma. The scutum is a bony prominence in the lateral portion of the middle ear and superior portion of the external auditory canal.
What is significant about finding cholesteatoma around the oval and round windows or eroding into the lateral semicircular canal?
What is significant about finding cholesteatoma around the oval and round windows or eroding into the lateral semicircular canal?
Cholesteatoma around the round window poses an increased risk of sensorineural hearing loss (SNHL) and suppurative labyrinthitis. In addition to the increased risk of suppurative labyrinthitis and SNHL, erosion into the lateral semicircular canal or disease around the oval window can rarely result in a perilymphatic fistula.
What are the risks you would discuss with the patient or the family in obtaining surgical consent for cholesteatoma surgery?
What are the risks you would discuss with the patient or the family in obtaining surgical consent for cholesteatoma surgery?
See Table attached.
Are audiograms useful in the treatment and management of cholesteatoma?
Are audiograms useful in the treatment and management of cholesteatoma?
Preoperative audiograms are indicated to assess baseline hearing, and for long-term follow-up after surgical removal. There are also medical-legal implications in the event of an operative complication.
What are the standard surgical approaches?
What are the standard surgical approaches?
There are various surgical approaches, including tympanotomy for disease contained in the mesotympanum, atticotomy, cortical mastoidectomy, canal wall up or down mastoidectomy, and modified-radical and radical mastoidectomy. Regardless of the type of surgery performed, the goal is for complete removal of disease, preservation of hearing, prevention of residual or recurrent disease, and improvement of ear hygiene. The specific surgical approach is mainly determined by extent of disease as well as surgeon comfort level. Facial nerve monitoring should also be considered, especially during revision surgery or cases with extensive disease. Facial nerve monitoring has been shown to improve identification of dehiscences, and although small, decreases rates of nerve injury, particularly in cases involving a facial recess approach.
Atticotomy is mainly used when disease is limited lateral to the malleus and incus as well as in the “attic.” Cortical mastoidectomy with or without facial recess is used with cholesteatoma extending medially to the ossicles and into the mastoid through the antrum.
The decision of canal wall up or down procedure is largely based on the ability to perform complete removal of cholesteatoma. Canal wall down procedures have been shown to provide improved postoperative physical exam, and superior intraoperative visualization of disease, specifically in difficult to view areas of the middle ear. Canal wall up procedures, alternatively, allow for preserved anatomy, and an improved ability for reconstruction resulting in a more physiologic middle ear with decreased aural care, improved ability to use hearing aids, and no water restrictions.
Why are surgeons reluctant to perform a canal wall down mastoidectomy, especially in young children?
Why are surgeons reluctant to perform a canal wall down mastoidectomy, especially in young children?
Although canal wall down mastoidectomy procedures provide superior visualization during and after cholesteatoma removal, they often result in difficulty reconstructing the middle ear and subsequent problems with the mastoid cavity. These include the need for life-long canal cleaning with increased risk of persistent otorrhea. It may also result in long-term water restrictions, vertigo induced by temperature changes with air or water exposure, and impaired use of hearing aids.
Why is a second-stage procedure required?
Why is a second-stage procedure required?
Planned second-stage procedures are performed due to increased rates of recurrence, especially in the pediatric population, and for evaluation of residual disease. Recurrent cholesteatomas are thought to be due to underlying chronic disease, such as eustachian tube dysfunction, creating a new retraction pocket for cholesteatoma formation. Residual disease is common with extensive cholesteatomas where disease was left inadvertently or intentionally due to involvement of critical structures.
Although common, the timing and decision to perform a second-stage procedure is not well established, and mainly depends on surgeon experience. It should also be noted that certain factors such as location of disease correlate with a higher risk of recurrence. Once the middle ear is deemed safe and free of cholesteatoma, an ossiculoplasty may be performed during a second look surgery.
