What are the procedure steps for endoscopically using Epidermal Growth Factor (EGF) to repair a tympanic membrane perforation not in active infection?

Endoscopic Procedure for Using EGF to Repair Tympanic Membrane Perforation

The most effective endoscopic procedure for using Epidermal Growth Factor (EGF) to repair non-infected tympanic membrane perforations involves careful preparation of the perforation edges, application of 1.0 μg EGF directly to the tympanic membrane, and weekly reapplications until complete closure is achieved, which typically occurs within 21 days.

Pre-procedure Assessment and Preparation

• Perform thorough otoscopic examination to confirm the diagnosis, noting the size and location of the perforation 1
• Ensure there is no active infection present in the ear canal or middle ear 1
• Discuss procedural techniques and risks with the patient and family prior to beginning the procedure 2
• Obtain informed consent after explaining the procedure, expected outcomes, and potential complications 2

Equipment Required

• Endoscope with appropriate light source and camera system 3
• Sterile instruments for atraumatic cleaning and manipulation 3
• EGF solution (1.0 μg concentration) 4
• Delivery vehicle (hydrogel or Gelfoam) 5
• Non-ototoxic topical preparations if needed 1

Procedure Steps

Step 1: Ear Canal Preparation

• Position the patient appropriately to visualize the perforation site 2
• Clean the external auditory canal using atraumatic suctioning under endoscopic guidance to avoid trauma 3
• Use carbon dioxide for insufflation if needed, as it is safer than air 2

Step 2: Perforation Edge Preparation

• Carefully trim or freshen the margins of the perforation under endoscopic visualization to stimulate the healing process 6
• Keep the area clean and dry to prevent contamination 1
• Avoid aggressive manipulation that could enlarge the perforation 3

Step 3: EGF Application

• Prepare the EGF solution at 1.0 μg concentration, which has shown 100% closure rates in experimental studies 4
• Apply EGF using one of two effective methods:
  • Option A: Direct application of 1.0 μg EGF to the perforation margins 4
  • Option B: Apply EGF (50 μg) formulated in hydrogel or shredded Gelfoam as a delivery vehicle 5

Step 4: Perforation Coverage

• If using a patch technique, place an atelocollagen/silicone bilayer membrane infiltrated with EGF over the perforation with the silicon layer facing outward 6
• Ensure the patch completely covers the perforation and adheres well to the remaining tympanic membrane 6

Step 5: Post-application Care

• Instruct the patient to keep the ear dry to prevent infection 1
• Recommend ear plugs or cotton balls coated with petroleum jelly when showering 1
• Prohibit swimming until the perforation has completely healed 1

Follow-up Protocol

• Schedule weekly follow-up visits for reapplication of EGF until complete closure is achieved 4
• Monitor for adverse effects such as external canal hypertrophy, which is less common with EGF than with other growth factors 4
• Complete closure can be expected within 21 days with weekly EGF applications 4
• Perform audiometric testing after closure to confirm restoration of hearing function 7

Important Considerations and Pitfalls

• Avoid irrigation of the ear canal when tympanic membrane perforation is present as this can lead to middle ear infection 1
• Do not use cotton-tipped applicators in the ear canal as they may cause further trauma 1
• Use only non-ototoxic preparations if any additional topical medications are needed 2
• For perforations with significant edema of the ear canal, a wick made of compressed cellulose may be placed to facilitate drug delivery 1
• Be aware that EGF has shown superior results compared to other growth factors like bFGF, with fewer side effects such as canal hypertrophy 4

Expected Outcomes

• Complete closure of tympanic membrane perforation within 21 days with EGF treatment 4
• Restoration of normal hearing function between 2-6 months after treatment 7
• Return of normal tympanic membrane vibration characteristics as measured by laser Doppler vibrometry 7

This endoscopic EGF application procedure offers a non-surgical alternative to traditional tympanoplasty with excellent closure rates and functional outcomes 4, 7.