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Repeated inflation does not prevent otitis media with effusion in a monkey model
1Department of Pediatric Otolaryngology, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA.
Objective:
Investigate the efficacy of repeated middle ear inflation with an inert gas (argon) for preventing the development of middle ear effusion in monkeys with functional eustachian tube obstruction.
Study Design:
Prospective controlled trial of daily middle ear inflation with five monkeys assigned to the inflation group and four to the control group.
Methods:
The right tensor veli palatini muscle of nine monkeys was paralyzed with botulinum toxin. Tympanometry was done before the procedure and then daily for 21 days. Presence and distribution of effusion were assessed before paralysis and on day 15 using magnetic resonance imaging (MRI). In five right ears inflation was done beginning at the first observation of negative middle ear pressure of < or =200 mm H2O and repeated on all days with pressures < or =-100 mm H2O. Four right ears served as uninflated controls.
Results:
Right middle ear pressure decreased in all animals over the course of the study. Pressure returned to near-ambient levels immediately following the argon inflation but was decreased to control levels at the subsequent observation on the following day. MRI at day 15 documented effusion in all right ears with no quantifiable differences in amount or distribution between ears that were and were not inflated with argon.
Conclusions:
Repeated inflation with an inert gas does not prevent middle ear effusion in monkeys with functional eustachian tube obstruction.
Insights
Repeatedly inflating the middle ear with argon gas did not prevent middle ear effusion in monkeys with eustachian tube dysfunction. This study found no difference in effusion between treated and control groups.
Area of Science:
- Otolaryngology
- Comparative Medicine
- Medical Imaging
Background:
- Middle ear effusion (MEE) is a common condition, particularly in children.
- Eustachian tube dysfunction (ETD) is a primary cause of MEE.
- Current treatments for ETD and MEE are limited.
Purpose of the Study:
- To investigate the efficacy of repeated middle ear inflation with an inert gas (argon) for preventing MEE.
- To assess the impact of argon inflation on middle ear pressure in a model of functional ETD.
Main Methods:
- A prospective controlled trial was conducted on nine monkeys with induced eustachian tube obstruction.
- Middle ear pressure was monitored via tympanometry, and effusion was assessed using magnetic resonance imaging (MRI).
- Five ears received daily argon inflation, while four served as uninflated controls.
Main Results:
- Middle ear pressure decreased in all animals but returned to near-ambient levels after inflation, only to decrease again by the next day.
- MRI at day 15 revealed effusion in all treated and control ears.
- No significant difference in the amount or distribution of effusion was observed between the inflated and control groups.
Conclusions:
- Repeated middle ear inflation with argon gas is ineffective in preventing middle ear effusion in a primate model of eustachian tube obstruction.
- This finding suggests that mechanical inflation may not overcome functional ETD to prevent MEE.