How does closure of tympanic membrane perforations affect hearing and middle ear mechanics? An evaluation in a patient cohort and temporal bone models.
OBJECTIVE
This study aimed to determine how tympanic membrane (TM) perforations and their closure, using a paper-patch technique, affect middle-ear mechanics and, thus, conductive hearing for different sizes of the TM perforation.


METHODS
Temporal bone (TB) study and prospective clinical trial.


METHODS
Tertiary referral center.


METHODS
Nine patients with chronic otitis media for more than 3 months.


METHODS
The TM perforations were closed with a paper patch in all 9 patients. In 5 of 9 patients, myringoplasty was performed. Matching TM perforations were created in a TB model (n = 8) and closed using the paper patch.


METHODS
Air-bone gap was measured in all 9 patients of the patient cohort with TM perforations before and after closure and in 5 patients after myringoplasty. Stapes velocity and sound pressure difference between the ear canal and middle-ear cavity were measured in TBs with intact TM, with TM perforations, and with the perforations closed by the paper patch. All measurements in the patient cohort and TBs were performed for different sizes of TM perforations to determine if the effects varied as a function of size.


RESULTS
Degree of the air-bone gap differed as a function of size of the TM perforations and its recovery after closure, and myringoplasty was independent of the size of the TM perforation in the frequency range of 0.25 to 4 kHz. In the TB measurements, although pressure difference across the TM was almost fully recovered by closing the perforation with a paper patch, recovery of the stapes motion was limited at frequencies above 4.5 kHz for larger sizes of TM perforations.


CONCLUSIONS
Hearing loss caused by TM perforations depends on the size of the perforation. Hearing returns almost completely across the frequency range after closure except above 4 kHz for larger perforations. This is because the structural damage caused by large TM perforations cannot be completely restored by application of a paper patch.
Clinic of Otorhinolaryngology-Head and Neck Surgery, University Hospital Zurich, Zurich, Switzerland. christof.roeoesli@usz.ch
Christof
C
Röösli
Jae Hoon
JH
Sim
Michailis
M
Chatzimichalis
Alex M
AM
Huber
D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D001301:Audiometry, Pure-Tone; D001309:Auditory Threshold; D002102:Cadaver; D015331:Cohort Studies; D004424:Ear Canal / Q000473:pathology; D004432:Ear, Middle / Q000503:physiopathology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006314:Hearing Loss, Conductive / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D013016:Sound; D013199:Stapes / Q000473:pathology; D013701:Temporal Bone / Q000473:pathology*; D018058:Tympanic Membrane Perforation / Q000503:physiopathology* / Q000601:surgery*; D055815:Young Adult