Residency · Residency · Otolaryngology
Chronic Otitis Media and Cholesteatoma
Overview
Chronic otitis media (COM) represents a spectrum of persistent middle ear and mastoid disease including chronic suppurative otitis media (CSOM), tympanic membrane perforation, and cholesteatoma. Surgical decision-making between canal wall up (CWU) and canal wall down (CWD) mastoidectomy remains an area of active controversy.
Classification of Chronic Ear Disease
Chronic Suppurative Otitis Media (CSOM)
CSOM is defined as persistent otorrhea through a perforated tympanic membrane for more than 6 to 12 weeks. It represents active mucosal disease without cholesteatoma and may be associated with granulation tissue, polyps, or tympanosclerosis.
Tympanic Membrane Perforation
Perforations are classified as central or marginal. Marginal perforations, which involve the annulus, carry a higher risk of cholesteatoma formation. The size and location of the perforation affect both the degree of hearing loss and the surgical approach to repair.
Cholesteatoma
Cholesteatoma is defined as keratinizing squamous epithelium in the middle ear or mastoid. It is locally destructive, eroding bone through enzymatic activity involving collagenase and osteoclast activation via cytokines. Although it is not a true neoplasm, it behaves aggressively and requires surgical management.
Cholesteatoma
Classification
Congenital cholesteatoma presents as a white mass behind an intact TM in a patient with no history of ear surgery, infection, or perforation. It is most commonly found in the anterior-superior quadrant and typically presents in young children. Primary acquired cholesteatoma arises from a retraction pocket, most often in the pars flaccida at Prussak space, and is related to chronic eustachian tube dysfunction with negative middle ear pressure. Secondary acquired cholesteatoma results from ingrowth of squamous epithelium through a marginal perforation or may be iatrogenic, implanted during prior ear surgery.
Pathophysiology Theories
The invagination (retraction pocket) theory is the most widely accepted explanation: chronic negative pressure causes retraction of the pars flaccida, creating a pocket that progressively accumulates keratin debris. The migration theory proposes that squamous epithelium migrates inward through a perforation. The squamous metaplasia theory suggests that middle ear mucosa undergoes metaplastic change to keratinizing epithelium. The basal cell hyperplasia (papillary ingrowth) theory posits invasion of epithelial cells through an intact or weakened basement membrane.
Clinical Presentation
The hallmark presentation is painless, foul-smelling otorrhea. Conductive hearing loss results from ossicular erosion. On examination, a retraction pocket filled with keratin debris, granulation tissue, or a polyp is typically identified. Advanced disease may manifest as vertigo from a labyrinthine fistula, facial weakness from facial nerve erosion, or symptoms of intracranial complications.
Complications
Ossicular erosion occurs in the vast majority of cases, with the long process of the incus being the most commonly affected structure in approximately 90% of cases. A labyrinthine fistula, most commonly involving the lateral semicircular canal, presents with vertigo and a positive fistula test. Facial nerve dehiscence or injury most commonly affects the tympanic segment. Intracranial extension may result in epidural abscess, brain abscess, meningitis, or sigmoid sinus thrombosis.
Imaging
High-resolution non-contrast CT of the temporal bone is the first-line imaging study. Findings include soft tissue opacity in the middle ear or mastoid, ossicular erosion, scutum blunting (characteristic of pars flaccida cholesteatoma), tegmen or sigmoid plate erosion, and labyrinthine fistula. MRI with diffusion-weighted imaging (DWI) is increasingly used in follow-up. Non-echo-planar DWI can detect residual or recurrent cholesteatoma larger than 2 to 3 mm, reducing the need for "second-look" surgery. Cholesteatoma characteristically shows restricted diffusion, appearing bright on DWI sequences.
Medical Management of CSOM
The cornerstone of medical management is aural toilet with suctioning under microscopy. Topical antibiotic-steroid drops such as ciprofloxacin/dexamethasone or ofloxacin are the primary pharmacologic treatment. Fluoroquinolones are ototopically safe without risk of ototoxicity, whereas aminoglycosides (gentamicin, neomycin) carry a theoretical ototoxicity risk when applied through a perforation. Culture-directed therapy is reserved for refractory cases. Patients should observe water precautions. Systemic antibiotics have a limited role in uncomplicated CSOM.
Surgical Management
Tympanoplasty
Tympanoplasty involves repair of the TM perforation without mastoidectomy and is indicated for a stable, dry ear with perforation and conductive hearing loss. Common graft materials include temporalis fascia, tragal perichondrium, and cartilage (either as an island graft or in palisade fashion).
Mastoidectomy Types
Canal Wall Up (CWU / Intact Canal Wall) Mastoidectomy
In this approach, the posterior EAC wall is preserved, offering better cosmetic and functional outcomes including water tolerance and ease of hearing aid use. However, it carries a higher recurrence/residual rate of up to 30-40% and often requires planned "second-look" surgery at 9 to 12 months, unless MRI DWI is used for surveillance. It is typically combined with tympanoplasty for ossicular reconstruction.
Canal Wall Down (CWD / Open Cavity) Mastoidectomy
In this approach, the posterior EAC wall is removed, creating a mastoid bowl. The recurrence rate is substantially lower at 5-10%, but patients require lifelong cavity maintenance including water avoidance and periodic cleaning. Hearing rehabilitation is more challenging due to a larger air-bone gap. Indications include extensive cholesteatoma, unreliable patient follow-up, an only hearing ear (to minimize recurrence risk), failed CWU procedures, and labyrinthine fistula with extensive matrix.
Controversy: CWU vs. CWD
| Feature | Canal Wall Up (CWU) | Canal Wall Down (CWD) |
|---|---|---|
| Posterior EAC wall | Preserved | Removed |
| Recurrence rate | 30-40% | 5-10% |
| Second-look surgery | Often required (unless MRI DWI) | Usually not needed |
| Water tolerance | Normal | Requires water precautions |
| Hearing aid use | Standard fitting | Difficult (open cavity) |
| Cavity maintenance | Not needed | Lifelong cleaning |
| Sinus tympani visualization | Limited | Better |
| Cosmetic outcome | Superior | Mastoid bowl |
No definitive randomized controlled trial has compared these two approaches. CWU offers the advantages of preserved anatomy, better hearing outcomes, and water tolerance. CWD provides lower recurrence rates, often requires only a single-stage surgery, and allows better visualization of the sinus tympani. The current trend favors CWU with MRI DWI surveillance to avoid second-look surgery. Endoscopic ear surgery is increasingly used as an adjunct to improve visualization, particularly of the sinus tympani, facial recess, and epitympanum.
Ossicular Reconstruction
Ossicular reconstruction is performed at the time of tympanoplasty or as a staged procedure. A partial ossicular replacement prosthesis (PORP) is used when the stapes superstructure is intact, while a total ossicular replacement prosthesis (TORP) is used when the superstructure is absent. Materials include titanium, hydroxyapatite, and autologous sculpted incus. Placing a cartilage cap over the prosthesis reduces the risk of extrusion.
| Prosthesis Type | Abbreviation | Stapes Superstructure | Bridges |
|---|---|---|---|
| Partial ossicular replacement | PORP | Intact | Incus to stapes capitulum |
| Total ossicular replacement | TORP | Absent | Tympanic membrane to footplate |
Staging Systems
The STAMCO staging system evaluates cholesteatoma by Site, Tympanic membrane status, Attic involvement, Middle ear involvement, Complications, and Ossicular status. The EAONO/JOS Classification represents an attempt to standardize cholesteatoma staging for meaningful outcome comparison across institutions.
<image>Coronal CT scan of a temporal bone with cholesteatoma showing soft tissue opacity in the epitympanum (Prussak space) with erosion of the scutum, lateral epitympanic wall destruction, and extension into the mastoid antrum. The ossicles are partially eroded. Labeled radiologic illustration with arrows pointing to key pathologic findings.</image>
<image>Intraoperative view comparing canal wall up (intact canal wall) mastoidectomy and canal wall down (open cavity) mastoidectomy. Left panel shows CWU with preserved posterior canal wall, the aditus ad antrum, and the facial recess approach to the middle ear. Right panel shows CWD with the posterior canal wall removed, creating a mastoid bowl communicating with the ear canal. Key structures labeled including facial nerve, lateral semicircular canal, sigmoid sinus, and tegmen.</image>
<image>Diagram showing the pathogenesis of acquired cholesteatoma via the retraction pocket theory. Sequential panels showing: (1) normal pars flaccida, (2) eustachian tube dysfunction causing negative middle ear pressure, (3) retraction of pars flaccida into Prussak space, (4) accumulation of keratin debris in the retraction pocket, (5) expansion and bony erosion of the scutum and ossicles. Medical illustration with cross-sectional views.</image>
Clinical Pearls
Foul-smelling, painless otorrhea is the hallmark of cholesteatoma until proven otherwise. Scutum erosion on CT is pathognomonic for pars flaccida cholesteatoma. The long process of the incus is the most commonly eroded ossicle, affected in approximately 90% of cases. A labyrinthine fistula (most commonly involving the lateral SCC) should be suspected when a patient with cholesteatoma presents with vertigo; the ear should not be irrigated during examination. When a labyrinthine fistula is identified intraoperatively, the cholesteatoma matrix over it may be intentionally left in situ to avoid sensorineural hearing loss, with staged removal planned later -- though this remains controversial. Non-echo-planar DWI MRI is revolutionizing cholesteatoma surveillance by detecting residual disease 2 to 3 mm or larger, potentially eliminating the need for second-look surgery. Fluoroquinolone otic drops are safe through a perforation, while aminoglycosides should be avoided. The contralateral ear should always be examined in cholesteatoma patients, as bilateral disease occurs in up to 10% of cases.
References
- Yung M, Tono T, Olszewska E, et al. "EAONO/JOS Joint Consensus Statements on the Definitions, Classification and Staging of Middle Ear Cholesteatoma." J Int Adv Otol. 2017;13(1):1-8.
- Stable I, Plodpai Y. "Canal wall up versus canal wall down mastoidectomy: systematic review and meta-analysis." J Laryngol Otol. 2021;135(9):764-774.
- De Foer B, Vercruysse JP, Bernaerts A, et al. "Detection of postoperative residual cholesteatoma with non-echo-planar diffusion-weighted magnetic resonance imaging." Otol Neurotol. 2008;29(4):513-517.
- Semaan MT, Megerian CA. "The pathophysiology of cholesteatoma." Otolaryngol Clin North Am. 2006;39(6):1143-1159.
