Tympanoplasty

Anesthesia Implications

Position: Supine, airplaned left, airplaned right, head turned away from field, Bed turned 180 degrees
Time: 1-2 hours (average)
Blood Loss: Very Low (5-10 ml)
Post-op Pain: Minimal (1-3)
Maintenance Paralytic: No

Anesthetic Approaches

  • GETT
  • GLMA
The Anesthesia

Preparation – You may need circuit extender and straight connector for ETT as bed will be turned 180 degrees and circuit will be laying on patient. Place goggles on the patient to further protect the eyes.

Positioning – In order for the surgeon to gain access to the surgical site, the head will be positioned on a headrest which might be lower than the OR table and extreme lateral rotation may be required.

NO nitrous – Increased pressure from the N2O can dislodge a tympanic graft.

No Paralytic – During the procedure, the surgeon will identify the facial nerve to prevent any possible damage. In order to do this he/she will use electrical stimulation via brainstem auditory evoked potential monitoring which means complete muscle relaxation needs to be avoided. At least 30% of the muscle response needs to be preserved.

Avoid BP elevation – Minimize excessive increases in blood pressure to improve bleeding within the surgical field. Relative hypotension can be effective but the pros and cons should be evaluated.

PONV – Be aware of the possibility of profound PONV. Since surgical stimulation of the vestibular system occurs during tympanoplasty (via H1 histamine and M1 Ach receptors), PONV is very likely.

180 degree turns (general considerations): Arrange lines and monitor cords in anticipation to turn. If turning right, keep cords and lines draped to the left. If turning left, keep cords and lines draped to the right. Have a circuit extension connected. Disconnect the circuit when turning and immediately reconnect.

The Pathophysiology

A tympanoplasty is performed to repair a perforation in the tympanic membrane (eardrum) or eradicate any disease in the middle ear. A perforation may be caused by head trauma, ear infections, cholesteatoma, a sudden change in pressure, etc.

This surgery is performed a minimum of three months after infection in the middle ear has been eliminated.

The Surgery

Tympanoplasty is one of the most common procedures performed on the middle ear. 

Tympanoplasty is essentially reconstruction of the tympanic membrane and ossicular chain. It is performed to remove disease in the middle ear and rebuild the ossicular chain. This may involve grafting. The graft, often temporalis facia (a fibrous layer that covers the temporalis muscle) is placed as a scaffold over which new epithelium will grow. Chronic middle ear changes will also be repaired in order to restore the function of the middle ear and improve hearing.

References: Barash. Clinical anesthesia. 8th edition. 2017.