What is the recommended concentration of trichloroacetic acid (TCA) for treating a small tympanic membrane perforation?

TCA Concentration for Small Tympanic Membrane Perforations

For treating small tympanic membrane perforations with chemical cauterization, use 50% trichloroacetic acid (TCA) applied to the perforation margins, though the FDA-labeled concentration is 5%. 1, 2

Evidence-Based Concentration Recommendations

The literature reveals a significant discrepancy between FDA labeling and clinical practice:

• Clinical practice uses 50% TCA concentration for chemical cauterization of tympanic membrane perforations, as documented in multiple studies showing successful closure rates of 73.75% 2
• FDA labeling specifies 5% TCA for topical use 3
• The higher 50% concentration has been used since Derlacki popularized this technique in 1953, with consistent success in closing small to moderate perforations 2

Application Technique

When performing chemical cauterization for small TM perforations:

• Apply 50% silver nitrate or TCA to cauterize the perforation margins to stimulate healing 2
• Cover the perforation with a thin sterile patch (aluminum foil or similar material) after cauterization 2
• Limit applications to a maximum of 5 sessions to achieve closure 2
• This technique works best for traumatic perforations and small to moderate-sized defects 2

Clinical Context and Success Rates

• Traumatic perforations show the highest success rates with chemical cauterization 2
• Larger perforations may be reduced to pinhole sizes, which can then be closed surgically if needed 2
• One case report documented successful closure of a tiny persistent perforation using trichloroacetic acid after initial spontaneous healing was incomplete 1
• This should be considered first-line management before surgical intervention for appropriate candidates 2

Important Caveats

• The 50% concentration used clinically is 10 times higher than the FDA-labeled 5% concentration 3, 2
• This represents off-label use of a higher concentration based on decades of clinical experience 2
• Keep the ear dry during treatment to prevent infection and optimize healing 4, 5
• Use only non-ototoxic preparations if concurrent infection requires treatment 4, 5