What is the purpose of inserting tympanostomy (ear) tubes in a patient with a perforated tympanic membrane?

Purpose of Tympanostomy Tubes in Perforated Tympanic Membrane

Tympanostomy tubes are not typically inserted in patients with pre-existing perforated tympanic membranes, as the tubes are designed to create a controlled opening in an intact tympanic membrane to ventilate the middle ear and prevent fluid accumulation. 1

Understanding Tympanostomy Tubes

Tympanostomy tubes (also called ventilation tubes, grommets, or pressure equalizing tubes) are small tubes inserted into the tympanic membrane that serve several key purposes:

• Provide middle ear ventilation and pressure equalization
• Allow drainage of middle ear fluid
• Prevent accumulation of fluid in the middle ear
• Reduce the frequency of acute otitis media episodes
• Improve hearing by eliminating conductive hearing loss from fluid
• Create a route for topical medication delivery to the middle ear 1, 2

Why Tubes Are Not Used in Perforated Eardrums

When a tympanic membrane is already perforated:

1. Redundant function: A perforation already provides the ventilation and drainage that a tube would provide
2. Risk of complications: Inserting a tube in a damaged membrane could:
   • Enlarge the existing perforation
   • Delay natural healing of the perforation
   • Increase risk of persistent perforation after treatment
   • Potentially introduce additional infection 3

Appropriate Management for Perforated Tympanic Membranes

Instead of tube insertion, management typically includes:

1. Observation and Protection

• Keep the ear dry
• Avoid water entry into the ear canal
• Use earplugs or petroleum jelly-coated cotton when showering
• Avoid swimming until cleared by a physician 4

2. Medical Management

• For infections with perforated membrane:
  • Use non-ototoxic topical antibiotics (ofloxacin 0.3% otic solution)
  • Avoid ototoxic preparations to prevent hearing loss
  • Pain management with acetaminophen or NSAIDs as needed 4

3. Surgical Repair Options

• Small perforations may heal spontaneously (75-90% within 3 months)
• Persistent perforations may require:
  • Gelatin film or paper patch myringoplasty (for smaller perforations)
  • Adipose (fat) myringoplasty
  • Formal tympanoplasty for larger or persistent perforations 3, 4

When Tympanostomy Tubes Are Indicated

Tubes are appropriate for intact tympanic membranes in these scenarios:

1. Chronic Otitis Media with Effusion (OME):

   • Bilateral OME for ≥3 months with hearing loss (16-40 dB)
   • OME in at-risk children (developmental delays, syndromes, etc.) 1

2. Recurrent Acute Otitis Media (AOM):

   • With middle ear effusion present at time of assessment
   • History of ≥3 episodes in 6 months or ≥4 episodes in 12 months 1

Complications of Tympanostomy Tubes

• Otorrhea (ear drainage) - most common complication
• Tube blockage
• Premature extrusion
• Persistent perforation after tube extrusion (occurs in ~2% with short-term tubes)
• Tympanosclerosis (31% of ears with tubes) 1, 5

Follow-up Recommendations

• Regular follow-up within 3 months to assess healing
• Audiometric testing at least 6 weeks after diagnosis
• Referral to otolaryngologist if perforation fails to heal after 3 months 4

Important Considerations

• Perforations from retained tubes (tubes that stay in too long) are more common (73%) than those occurring after normal extrusion (27%) 3
• The median duration before complications from retained tubes is 48 months 3
• Using an appropriate treatment algorithm for perforated tympanic membranes can achieve healing rates of up to 91% after the first intervention 3

In summary, tympanostomy tubes serve no purpose in an already perforated tympanic membrane and may complicate healing. The appropriate approach is to manage the perforation directly through protection, medical treatment of any infection, and surgical repair if needed.