What are the indications for a modified radical mastoidectomy (MRM) in patients with chronic otitis media (COM)?

Indications for Modified Radical Mastoidectomy

Modified radical mastoidectomy (MRM) is indicated for chronic otitis media with cholesteatoma, chronic mastoiditis, or chronic active otitis media with cholesteatoma and mastoiditis, particularly when there is extensive disease requiring complete eradication and creation of a safe, dry ear. 1

Primary Indications

Cholesteatoma with Chronic Otitis Media

• MRM is the definitive surgical treatment for cholesteatoma with tympanic membrane perforation and chronic otitis media, aiming to completely remove cholesteatoma, control infection, repair the tympanic membrane, and preserve or improve hearing when possible 2
• The presence of cholesteatoma significantly alters management, making mastoidectomy necessary rather than optional 3
• Cholesteatoma appears as abnormal whitish material in the middle ear, often associated with tympanic membrane retraction pockets or perforations 2

Advanced Chronic Otitis Media

• MRM is effective for eradication of advanced chronic otitis media, particularly in the attico-antral type 1, 4
• The procedure is especially beneficial in populations with low socioeconomic status and poor follow-up potential, as it provides maximum benefit in terms of disease eradication and hearing improvement in a single-stage procedure 4

Acute Mastoiditis with Complications

• Subperiosteal abscess formation indicates advanced disease requiring modified radical mastoidectomy 3
• When acute mastoiditis fails conservative management (IV antibiotics with or without myringotomy for 48 hours), surgical intervention with mastoidectomy becomes necessary 5
• Significant conductive hearing loss suggests extensive middle ear involvement, necessitating surgical intervention 3

Specific Clinical Scenarios

Ossicular Chain Involvement

• Ossicular chain erosion is present in approximately 91% of cases requiring MRM 1
• The presence or absence of stapes suprastructure is a major factor in determining hearing outcomes (p=0.025 preoperatively, p=0.031 postoperatively) 1
• Significant hearing loss indicates substantial middle ear involvement requiring surgical intervention 3

Failed Conservative Management

• Conservative management with antibiotics alone has only a 10% success rate in acute mastoiditis, while antibiotics plus mastoidectomy has a 22% success rate 5, 3
• Prior antibiotic treatment does not eliminate the risk of developing complications, as 33-81% of patients with mastoiditis had received antibiotics before diagnosis 5, 3

Anatomical Considerations

"Drum Sinus" Type CSOM

• For "drum sinus" type chronic suppurative otitis media (characterized by specific measurements of tympanic sinus size, extent of meningeal plate lowering, and sigmoid ante-displacement), MRM via epitympanum approach can be performed 6
• This approach achieves an 81.5% dry ear rate and 77.8% successful tympanic membrane repair rate at 3 months 6

Mastoid Cavity Issues

• Open cavity techniques are indicated when there is persistent intermittent drainage (occurring in 20-60% of cases) that requires exteriorization of disease 7
• MRM with cavity reconstruction using Palva flap and medial graft technique achieves 93% complete obliteration of the mastoid cavity and successful tympanic membrane reconstruction 7

Expected Outcomes

Disease Control

• MRM achieves a dry ear in 78% of patients with a 3% recurrence rate 1
• The procedure does not worsen hearing when properly performed 1

Hearing Results

• MRM provides significant improvement in air conduction (mean gain 21.24 dB) and closure of air-bone gap (mean 15.62 dB) 4
• Hearing results after MRM are better after primary surgery than after revision surgery 8
• No significant differences exist between hearing results obtained by MRM and intact canal wall mastoidectomy, irrespective of ossicular replacement prostheses use 8

Important Caveats

• Imaging with high-resolution CT temporal bone with IV contrast is essential to fully evaluate the extent of disease, bony erosion, and potential intracranial complications before proceeding with MRM 3
• MRI may be complementary if intracranial complications are suspected, as it has higher sensitivity for detecting these complications 9, 3
• Patients with diabetes or immunocompromised states require special attention due to increased risk of complications 2