Tympanoplasty Laboratory Medicine

Updated: Mar 02, 2016
  • Author: Brian Kip Reilly, MD; Chief Editor: Arlen D Meyers, MD, MBA  more...
  • Print
Laboratory Medicine

Laboratory Medicine Summary

Audiometric Testing

Audiometry should be performed preoperatively in all surgical candidates. Tympanometry can add useful information in younger children who are difficult to properly examine. The primary reason for audiometric analysis is to establish the degree of conductive hearing loss. Perforations usually cause low-frequency conductive loss. [17] If underlying ossicular discontinuity exists and is not addressed during surgery, then postoperative hearing can be worse despite an intact neo-tympanum. One should consider ossicular involvement if the conductive hearing loss is flat across all frequencies or greater than 35 db. Finally, the presence and degree of any sensorineural hearing loss should be documented preoperatively.

Radiographic Testing

Computed tomography (CT) and magnetic resonance imaging (MRI) is not essential but may be indicated in patients in whom a concern for cochlear, labyrinthine, or intracranial pathology exists. Other patients who might be considered for preoperative imaging include patients with a history of facial palsy, children with craniofacial abnormalities, and revision cases in which the anatomy may be distorted.

Pre-operative imaging assists the surgeon in preoperatively identifying pathology and planning surgery. CT scan should be ordered when concern exists for cholesteatoma and in patients with previous mastoid surgery, otalgia, or vertigo. MRI is beneficial for delineating the integrity of the dura as well as detecting small retrocochlear lesions such as acoustic neuromas.