Learning Objectives:
Intro: The treatment of discharging mastoid cavities is hampered by long-term deterioration of the surgical reconstruction.
We hypothesised that it would be optimal to use a graft that would become incorporated into, and indistinguishable from the skull bone.
We developed a simplified technique of posterior canal wall reconstruction using a free cortical bone graft in patients who have discharging mastoid cavities.
Method: Technique: Reconstruction of the posterior canal wall with a free cortical bone graft harvested from the cortex of the mastoid process.
Patients: 40 patients with discharging mastoid cavities.
The following were assessed at one year following surgery:
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1. Integrity of the barrier formed by the cortical bone graft.
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2. Integrity of the keratinising epithelium of the ear canal.
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3. Patient report of ear discharge.
Results: Adequate bone grafts were obtainable in all cases.
An intact barrier between the mastoid cavity and a new, physiological ear canal were maintained at one year in all cases, bar one, when a recurrent cholesteatoma developed through a defect between the graft and facial ridge, whereafter the technique was modified.
All but one patient grew intact keratinising epithelium lining their ear canal and tympanic membrane. Healing was initially prolonged, so a pericranial flap was incorporated into the technique.
All but one patient reported a dry ear at one year.
The small number of revision operations allowed us to confirm that the bone grafts had become fully incorporated into the temporal bone.
Conclusions: Reconstruction of the posterior ear canal using a cortical bone is an effective procedure for treating mastoid cavities which are unstable and symptomatic.
Learning Points: Cortical bone becomes vitalised and incorporated into the skull and so has the potential to be exceptionally robust in the long term.
