Bulla osteotomy

Introduction

• Surgical access to the tympanic bulla via a ventral approach osteotomy.

Uses

• Investigation and treatment of otitis media when medical therapy fails.
• For middle ear bacterial and fungal infections.
• Where there is extension of the infection into the bone of the tympanum or external bony meatus, or where the tympanum has ruptured extending the disease to an otitis externa.
• Investigation and treatment of neoplasia of the middle ear.

Advantages

• Allows full exposure of the contents of the tympanic bulla.
• Facilitates sampling for bacterial or fungal culture and histopathology.
• Facilitates curettage, drainage and flushing of purulent debris.
• Provides a route for administration of topical treatment.
• Allows placement of antibiotic impregnated polymethylmethacrylate PMMA beads.

Disadvantages

• Post-operative complications.
• Advanced surgical skills and specialized instrumentation are necessary.

Requirements

Materials required

Minimum equipment

• Standard surgical pack.
• Hand-held (Hohmann) or self-retaining (Gelpi) tissue retractors. 
• Rongeurs.
• Steinmann pin and hand chuck.
• Volkmanns curette.

Ideal equipment

• Radiosurgery.
• Irrigation/suction apparatus.
• Sterile burr.

Minimum consumables

• Suture materials.
• Swabs and media for aerobic, anaerobic bacterial and fungal cultures.
• Histopathological fixative.
• Catheters and surgical drains.

Preparation

• 10 min.
• Up to 30 min if a combined surgical approach via the external ear canal is needed.

Sequelae

Complications

• Recurrence or extension of localized infection.
• Inner ear damage caused during curettage of the bulla or as an extension of infection.
• Facial or hypoglossal nerve damage.
• Horners syndrome    .
• Hemorrhage or facial edema as a result of damage to or constriction of the major vessels in the area.
• Torticollis/head tilt    .
• Ileus    .

Prognosis

• Guarded.

Reasons for treatment failure

• Persistence of infection as a consequence of failure to remove all infected debris from the bulla, due to deep penetration of infection into bone and inner ear structures, that cannot be curetted.
• Post-operative infection.

Sources

Publications

• Recent references from PubMed.
• Chow E P, Bennett R A & Dustin L (2009) Ventral bulla osteotomy for treatment of otitis media in a rabbit.  J Exotic Pet Med 18 (4), 299-305. 
• Capello V (2004) Surgical treatment of otitis externa and media in pet rabbits.  Exotic DVM 6 (3) 15-21.