Tympanoplasty

Definition and Goals

1. Eradicate middle ear infection/pathology
2. Restore middle ear function - specifically the middle ear transformer mechanism
3. Repair the tympanic membrane (TM)
4. Reconstruct the ossicular chain (ossiculoplasty) when needed

Middle Ear Mechanics - Functional Basis

• Ossicular coupling: Sound pressure gain through TM and ossicular chain. Mean middle ear gain is ~20 dB at 250-500 Hz, peaks ~25 dB at 1 kHz, then decreases ~6 dB/octave above 1 kHz.
• Acoustic coupling: Direct sound pressure difference between oval and round windows. Normally negligible but becomes significant in diseased/reconstructed ears.
• TM perforation effect: Reduces the sound pressure difference across TM, causing frequency-dependent hearing loss proportional to perforation size. Hearing loss does NOT vary significantly with perforation location.
• Middle ear aeration: A minimum of ~0.5 mL of middle ear air is required to maintain ossicular coupling within 10 dB of normal.

Preoperative Evaluation

• Detailed history: infections, drainage, prior surgery, PE tube placement
• Otomicroscopic examination: perforation type (central vs. marginal), extent, TM remnant health, myringosclerosis, atrophic areas
• Central perforation: surrounded circumferentially by residual TM
• Marginal perforation: no TM remnant between part of the perforation and bony canal wall
• Perforations >50% of the membrane have lower success rates
• Eustachian tube function assessment (no current test reliably predicts postoperative function when perforation is present)
• Complete audiometry + tuning fork tests
• Radiographic evaluation usually not needed for dry central perforations

Surgical Approaches

Graft Techniques

Medial (Underlay) Technique

• Graft placed medial to the TM remnant and manubrium of malleus
• Easier to master; high success rates
• Most common technique today
• Advantages: avoids blunting of the anterior sulcus, no epithelial pearl formation

Lateral (Overlay) Technique

• Graft placed lateral to the malleus handle
• Better for total perforations and when cholesteatoma lines the TM remnant (allows excision of remnant)
• Complications: anterior sulcus blunting (~10-15%), epithelial pearl formation, graft lateralization
• Requires meticulous removal of all squamous epithelium

Graft Materials

Temporalis Fascia (TF)

• Most widely used; high success rates (88-97% graft take)
• Harvested from the temporalis muscle fascia via postauricular or endaural approach

Perichondrium

• Harvested from tragus or concha
• Good results; often used with cartilage as composite graft

Cartilage Grafts

• Eustachian tube dysfunction (ongoing or anticipated)
• Revision surgery
• Perforation >50%
• Ear draining at time of surgery
• Atelectatic ear / retraction pockets
• Reconstruction after cholesteatoma
• Bilateral perforations

• Palisade technique: strips of cartilage arranged side-by-side
• Composite cartilage/perichondrium island graft: eccentrically placed cartilage disk attached to perichondrial flap
• Butterfly/inlay technique: for small-to-medium perforations without elevating a tympanomeatal flap; scored circumferentially 2 mm and nestled between freshened perforation edges

Fat Graft

• For small persistent perforations (e.g., after PE tube extrusion), failed myringoplasty
• Can be done under local anesthesia as office/ambulatory procedure
• Earlobe fat harvested via small incision, inserted in dumbbell fashion

Ossiculoplasty (Ossicular Chain Reconstruction)

Common Causes of Ossicular Problems

• Erosion by cholesteatoma (most commonly the lenticular process or long process of incus)
• Trauma (longitudinal temporal bone fractures - incus dislocation most common)
• Chronic infection with ossicular necrosis

Audiometric Patterns

• Ossicular discontinuity: near-maximal (~55-60 dB) conductive loss across all frequencies; deep tympanometric pattern (type Ad)
• Ossicular fixation: low-frequency predominant conductive loss; flat tympanogram; Carhart notch (5-10-15-5 dB dip at 500-1000-2000-4000 Hz in bone conduction)
• Partial incudostapedial separation (fibrous union): air-bone gap greater in high frequencies

Prosthesis Types

Materials

• Autografts: Reshaped incus or cortical bone/cartilage (biocompatible, low extrusion, no cost, but time-consuming to shape; concerns about cholesteatoma recurrence)
• Allografts (synthetic prostheses): Titanium, hydroxyapatite, plastipore/TORP/PORP. Trend has shifted toward allografts over autografts.
• Cartilage placed between TM and prosthesis reduces extrusion risk

Anesthesia

• General anesthesia: preferred in children and anxious adults
• Local anesthesia: feasible for adults; ear canal injected with 1% lidocaine + epinephrine 1:100,000 for vasoconstriction
• Povidone-iodine (Betadine) prep should not enter the middle ear

Postoperative Care

• Discharged same day (next day if nausea/vomiting)
• Mastoid dressing and drain removed next day
• Antibiotic ear drops at bedtime
• Water precautions; cotton ball with petroleum ointment when showering
• No nose blowing until TM healed; open mouth if sneezing
• First visit: 1 week (remove Merocel/Pope's ear wick)
• Second visit: 3-4 weeks (suction remaining Gelfoam; cauterize granulations with 25% silver nitrate)
• Hearing improvement noted within 6-8 weeks
• Audiogram at 4-6 months postoperatively

Outcomes

Negative Prognostic Factors

• Eustachian tube dysfunction
• Presence of cholesteatoma or atelectasis
• Previous tympanoplasty failure
• Lateralized tympanic membrane
• Smoking
• Drainage at time of surgery
• Perforation >50% of TM

Complications and Failure Modes

Causes of Tympanoplasty Failure

• Persistent/recurrent perforation
• Blunting of the anterior sulcus (associated with overlay technique; requires meticulous technique to prevent)
• Graft lateralization (graft migrates away from manubrium; can occur if placed lateral to manubrium at primary surgery)
• Epithelial pearl formation (keratin accumulation; associated with overlay technique; meticulous epithelium removal at primary surgery is preventive)
• Conductive hearing loss

Contributing Factors

• Poor Eustachian tube function
• Inadequate visualization of anterior sulcus
• Extensive tympanosclerosis of TM remnant
• Inadequate Gelfoam support anteriorly
• Recurrent/residual cholesteatoma

Cholesteatoma After Tympanoplasty

• Recurrent cholesteatoma: ~14% after intact canal wall (ICW) mastoidectomy
• Residual cholesteatoma: ~12% after ICW mastoidectomy
• Higher in children (25% vs 11.7% in adults)
• Requires "second look" procedure at 12 months after ICW mastoidectomy

Revision Tympanoplasty

• Slightly less successful than primary cases but still satisfactory
• Cartilage "shield" technique for revision: graft-take ~93.5%, majority achieve air-bone gap <25 dB

Special Situations

Pediatric Tympanoplasty

• Generally deferred until age 7-8 (Eustachian tube more mature)
• Higher failure rates than adults due to ongoing ET dysfunction and otitis media
• Cartilage grafts preferred

Atelectatic Ear

• End-stage Eustachian tube dysfunction
• Management controversial (observe vs. cartilage tympanoplasty)
• Risk: converting a dry, asymptomatic ear into one requiring ongoing care

Secondary Acquired Cholesteatoma

• Keratinized epidermis migrates into middle ear through perforation
• Suspect when: no retraction/adhesion; smooth epidermal transition around perforation margins; opaque TM adjacent to perforation
• Lateral technique preferred to allow complete excision of cholesteatoma-lined remnant

Recent Evidence (2024-2026)

• A 2024 meta-analysis (PMID 38415937) comparing endoscopic vs. microscopic tympanoplasty found endoscopic approaches offer comparable outcomes with less invasiveness.
• A 2025 systematic review (PMID 39786316) on endoscopic vs. microscopic ossicular chain reconstruction showed similar functional hearing outcomes between approaches.
• A 2024 meta-analysis (PMID 39113516) evaluated tympanic cavity packing in Type 1 tympanoplasty.