Myringoplasty — Detailed Overview

1. Definition & Goals

• Restore an intact, infection-resistant TM
• Improve conductive hearing loss
• Prevent recurrent middle ear disease (cholesteatoma, repeated infections)
• Re-establish the transformer mechanism of the middle ear

2. Indications

• Chronic tympanic membrane perforation (central, not marginal)
• Chronic otitis media (tubotympanic/mucosal type, inactive — dry ear)
• Conductive hearing loss from TM perforation
• Dysventilation syndromes and atelectasis

3. Surgical Approaches — Incision Positions

A. Postauricular (Retroauricular) Approach — Most Common

• A Wilde's incision is made 5–10 mm behind the postauricular sulcus, running from the superior attachment of the auricle to its inferior pole
• The skin and subcutaneous tissue are incised down to the periosteum
• The periosteum is marked and incised; a Lempert elevator elevates the periosteum anteriorly to expose the spine of Henle and the bony canal
• Provides wide exposure, ideal for large perforations, revision cases, and simultaneous mastoidectomy
• Allows generous graft harvesting (temporalis fascia)

B. Endaural (Rosen's) Incision

• Incision placed between the tragus and helix in the incisura terminalis (notch of Rivinus)
• Extended superiorly into the conchal bowl
• Used when more limited exposure is needed; intermediate between transcanal and postauricular approaches

C. Transcanal Approach

• No external skin incision
• Tympanomeatal flap elevated entirely through the ear canal
• A vascular strip incision is made: vertical incisions at 6 o'clock and 12 o'clock connected by a horizontal incision just lateral to the annulus
• Limited to small to moderate central perforations with adequate canal width
• Can be done under microscope or endoscope (endoscopic myringoplasty)

4. Vascular Strip

5. Graft Material

6. Graft Placement Techniques

Underlay (Medial) Technique — Most Common

• Graft placed medial to the fibrous annulus and TM remnant
• Graft rests on the medial surface; supported by Gelfoam packing in the middle ear
• Ideal for posterior and inferior central perforations
• Less technically demanding; avoids risk of lateralization or anterior blunting
• Middle ear is entered by lifting the annulus out of the tympanic sulcus with a pick or hook

Overlay (Lateral) Technique

• Graft placed lateral to the fibrous layer of TM remnant, medial to the malleus handle
• Requires complete removal of squamous epithelium from the TM remnant surface (to prevent iatrogenic cholesteatoma)
• Requires bony canalplasty for anterior visualization
• Useful for large perforations, anterior perforations, revision cases
• Greater vascular ingrowth potential; promotes epithelialization

7. Instruments Used

General Set

8. Step-by-Step Operative Technique (Postauricular Underlay)

1. Positioning: Supine, head turned contralateral; operating microscope positioned
2. Infiltration: Local anaesthetic with adrenaline (1:100,000) in canal and postauricular area
3. Incision: Wilde's postauricular incision, 5–10 mm behind sulcus
4. Graft harvest: Temporalis fascia harvested, thinned with fascia press, allowed to dry
5. Periosteal elevation: Lempert elevator exposes bony canal; self-retaining retractor placed
6. Vascular strip incisions: Sickle knife at 12 and 6 o'clock, connected horizontally just lateral to annulus
7. Tympanomeatal flap elevation: Flap elevated from lateral to medial using drum elevator; annulus freed from sulcus with Rosen needle
8. Middle ear entry: Posterior half of drum lifted; chorda tympani identified and preserved
9. Perforation edge freshening: Margins of perforation denuded of epithelium with small curette or pick to create a raw edge for graft adherence
10. Gelfoam packing: Absorbable gelatin foam placed in middle ear for graft support
11. Graft placement: Dry fascia slid medial to TM remnant and annulus; positioned over Gelfoam
12. Flap repositioning: Tympanomeatal flap laid back over graft
13. Canal packing: Gelfoam strips or ribbon gauze placed lateral to graft in canal
14. Wound closure: Postauricular wound closed in layers (periosteum, subcutaneous, skin)
15. Dressing: Mastoid dressing applied

9. Postoperative Care

• Ear kept dry for 4–6 weeks
• Antibiotic eardrops after canal pack removal (1–2 weeks)
• Avoid nose blowing; Valsalva manoeuvre contraindicated
• Audiogram at 6–8 weeks to assess hearing improvement
• Success rates for Type I tympanoplasty: 80–95% (graft uptake); no single technique or approach has been shown superior in meta-analyses

10. Complications

Surgical Images

Complications of CSOM — Tubotympanic (Mucosal/Safe) Type

Classification (Box 141.1 — Cummings Otolaryngology)

Extracranial (Intratemporal)

1. Acute mastoiditis
2. Coalescent mastoiditis
3. Chronic mastoiditis
4. Masked mastoiditis
5. Postauricular (subperiosteal) abscess
6. Bezold abscess
7. Temporal abscess
8. Petrous apicitis (Gradenigo syndrome)
9. Labyrinthine fistula
10. Facial nerve paralysis
11. Acute suppurative labyrinthitis
12. Encephalocele and CSF leakage

Intracranial

1. Meningitis
2. Brain abscess
3. Subdural empyema
4. Epidural abscess
5. Lateral (sigmoid) sinus thrombosis
6. Otitic hydrocephalus

Routes of Spread

Extracranial Complications in Detail

1. Acute Mastoiditis

• Most common extracranial complication
• Occurs when AOM/COM fails to resolve → mucosal edema blocks aditus ad antrum → pus accumulates in mastoid air cells
• Features: Fever, post-auricular pain, tenderness, erythema, auricle displaced anteroinferiorly
• Pathogens: S. pneumoniae, S. pyogenes, S. aureus, H. influenzae
• Coalescent mastoiditis: Bony septa between air cells dissolve → empyema cavity forms
• Managed with IV antibiotics ± myringotomy ± cortical mastoidectomy

2. Subperiosteal (Postauricular) Abscess

• Pus erodes through the lateral cortex of the mastoid → collects between periosteum and bone
• Pinna pushed anteriorly and laterally; post-auricular sulcus obliterated
• Requires incision and drainage + mastoidectomy

3. Bezold Abscess

• Pus perforates the medial/inner cortex of the mastoid tip → tracks along sternocleidomastoid (SCM) muscle sheath into the neck
• Presents as a deep neck swelling along the anterior border of SCM
• Can track to mediastinum → descending necrotising mediastinitis (rare, life-threatening)

4. Temporal (Zygomatic) Abscess

• Pus extends anteriorly through zygomatic air cells → subcutaneous abscess over the zygoma/temple

5. Petrous Apicitis (Gradenigo Syndrome)

• Infection spreads through the petrous apex air cells
• Classic Gradenigo's triad:
  • Ipsilateral CN VI palsy (abducens — lateral rectus palsy → diplopia)
  • Deep retro-orbital/facial pain (CN V — Meckel's cave irritation)
  • Otorrhoea (purulent discharge)
• Managed with IV antibiotics; surgical drainage if no improvement

6. Labyrinthine Fistula

• More common with cholesteatoma, but can occur in tubotympanic CSOM with granulation tissue
• Usually involves the lateral semicircular canal (most exposed)
• Presents with sensorineural hearing loss, vertigo, positive fistula test (pressure-induced nystagmus)
• Managed surgically — fistula sealed with fascia graft

7. Facial Nerve Paralysis

• Bacteria reach the facial nerve via congenital dehiscences of the fallopian canal or erosion by granulation tissue
• In CSOM without cholesteatoma: affects the horizontal (tympanic) segment near the stapes
• Onset is usually gradual (unlike cholesteatoma, where it can be acute)
• Progression from partial to complete palsy
• Managed by mastoidectomy + facial nerve decompression; best outcomes if decompressed within 1 week of onset
• If nerve undergoes complete degeneration before surgery, prognosis is poor

8. Acute Suppurative Labyrinthitis

• Bacterial invasion of the labyrinth → immediate, total, irreversible loss of auditory and vestibular function
• Extension usually via weakened oval window membrane or round window
• Presents with sudden profound SNHL + severe vertigo + nausea/vomiting
• Treated with high-dose IV antibiotics; hearing loss is permanent
• Can progress to meningitis via the cochlear aqueduct or IAC

Intracranial Complications in Detail

1. Meningitis

• Most common intracranial complication overall
• Spread via: labyrinth → cochlear aqueduct → subarachnoid space; or direct dural erosion
• Features: high fever, severe headache, neck stiffness, photophobia, Kernig's/Brudzinski's signs
• CSF: turbid, raised protein, low glucose, polymorphs, organisms on gram stain
• Managed with IV antibiotics (penicillin/cephalosporin/chloramphenicol) + mastoidectomy after stabilisation

2. Brain Abscess

• Second most common intracranial complication in COM
• Temporal lobe abscess (via tegmen erosion) and cerebellar abscess (via sigmoid sinus or posterior fossa erosion)
• Stages: encephalitis → central softening → abscess capsule formation
• Features: headache, fever (may be low grade or absent), focal neurological deficits, seizures, papilloedema
• CT/MRI: ring-enhancing lesion
• Managed: neurosurgical drainage (aspiration/excision) + IV antibiotics + mastoidectomy

3. Epidural Abscess

• Pus accumulates between the dura and inner cortex of temporal bone
• Often asymptomatic or mild headache; discovered incidentally on CT
• Dura acts as a barrier → less serious unless it progresses
• Treated by mastoidectomy with evacuation of abscess

4. Subdural Empyema

• Pus between dura and arachnoid
• Spreads rapidly over the cerebral surface → very serious
• Features: fever, headache, meningism, focal deficits, altered consciousness, seizures
• Neurosurgical craniotomy/drainage is priority; then mastoidectomy

5. Lateral (Sigmoid) Sinus Thrombosis

• Infection from mastoid air cells → perisinus abscess → thrombophlebitis → sigmoid sinus thrombosis
• Features:
  • Picket-fence (hectic) fever — characteristic spiking fever with rigors
  • Griesinger's sign: oedema and tenderness over mastoid emissary vein (posterior to mastoid)
  • Tobey-Ayer test: compression of ipsilateral internal jugular vein → no rise in CSF pressure (thrombosis blocks venous return)
• Can embolise → septic pulmonary emboli, septicaemia
• Managed with mastoidectomy, removal of infected thrombus, IV antibiotics; anticoagulation controversial

6. Otitic Hydrocephalus

• Raised intracranial pressure without evidence of abscess, meningitis, or thrombosis
• Mechanism: lateral sinus thrombosis → impaired CSF absorption at arachnoid granulations → raised ICP
• Features: severe headache, papilloedema, diplopia (CN VI palsy), visual changes; CSF is normal in composition
• Treated with acetazolamide, serial lumbar punctures, or CSF shunting; mastoidectomy for underlying disease

Key Points: Why Tubotympanic is "Safer" But Not Safe

Investigations for Suspected Complications

• CT temporal bone — bony erosion, mastoid opacification, sinus plate erosion
• MRI brain with contrast — intracranial extension, abscess ring enhancement, sinus thrombosis
• CBC — leukocytosis
• Blood cultures — septicaemia
• Lumbar puncture — CSF analysis for meningitis (contraindicated if raised ICP with brain abscess/subdural empyema)

Management Principles

1. IV broad-spectrum antibiotics covering aerobes and anaerobes (e.g., ceftriaxone + metronidazole)
2. Mastoidectomy — to eradicate the primary source
3. Neurosurgical intervention (aspiration/drainage) for intracranial collections
4. Sequential or concurrent treatment of the ear and intracranial complication
5. Post-treatment follow-up CT/MRI to confirm resolution — new complications can emerge