Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty

The Eustachian Tube Dysfunction in Children: Anatomical Considerations and Current Trends in Invasive Therapeutic Approaches

The eustachian tube (ET) has a crucial role in the physiology of the middle ear. Thus, any condition that renders the tube dysfunctional is directly implicated with middle ear pathophysiology, like in the case of acute otitis media and otitis media with effusion. Children are more vulnerable to pathologies of the middle ear, primarily due to the immature development of their eustachian tubes. Otitis media with effusion, apart from being a burden for hearing, with direct consequences for speech development, may also be implicated in cholesteatoma formation. Medical therapy is not practically effective for the treatment of effusion. Moreover, the established surgical approaches, like grommets and adenoidectomy, deal only indirectly with the problem since they are not addressing the dysfunctional ET itself. An emerging interventional approach that intends to restore the function of the tube is the transnasal balloon dilation of the cartilaginous part of the ET. Growing international experience indicates that this promising technique is safe and effective. In the current review, we aim to provide background information on the anatomy, physiology, and pathophysiology of the ET and to present the progress of the balloon dilation technique with emphasis on pediatric patients.

In vivo study measuring middle ear pressure during various stages of Eustachian tube balloon dilation

OBJECTIVE

Documentation of middle ear pressure at different stages of balloon Eustachian tuboplasty and assessing risk of barotrauma with this procedure.

MAIN OUTCOME MEASURES

Middle ear pressure measurements in patients undergoing balloon Eustachian tuboplasty at the time of pre-insertion, catheter insertion, inflation, one minute post inflation, deflation, and catheter withdrawal, as well as documentation of pressure change in the middle ear between different stages.

RESULTS

A total of 24 patients and 45 Eustachian tubes, 11 females and 13 males, with an average age of 55.6 years were included in this study. Middle ear pressure values during the active stages of the procedure varied from -356 to +159 daPa. The overall greatest negative pressure change measured was -515 daPa from catheter insertion to immediately post balloon inflation. The overall greatest positive pressure change measured was +418 daPa from immediate catheter inflation to one minute post inflation.

CONCLUSIONS

There was no consistent pattern of middle ear pressure change noted during the different stages of balloon Eustachian tuboplasty as both positive and negative middle ear pressure changes were noted at the time of balloon dilation. Dangerous levels of middle ear pressure raising concern for barotrauma were not identified during the procedure.

LEVEL OF EVIDENCE

Level IV.

In Vivo Measurement of Middle Ear Pressure Changes during Balloon Eustachian Tuboplasty

Background

Balloon Eustachian tuboplasty (BET) is known as a treatment for chronic obstructive Eustachian tube dysfunction (OETD). The precise mechanism of action is not fully understood. Observations in sheep cadavers and human cadavers have shown specific middle ear pressure changes related to BET.

Methods

In this prospective study using a microfibre optical pressure sensor, pressure changes during BET were for the first time monitored transtympanically in five normal human middle ears in vivo.

Results

Middle ear pressure changes during 21 BETs consisted of five stages (insertion, inflation, deflation, withdrawal, and recovery). The highest pressure change occurred in most of the cases during the withdrawal of the balloon catheter. Withdrawal pressure yielded a mean middle ear pressure of 4.76 mmHg (61.89 daPa) with a maximum of 13.88 mmHg (179.55 daPa). Pressure amplitudes capable of causing barotrauma to ear structures were not detected. Internal carotid artery dehiscences were detected as causative of sinusidual pressure changes.

Conclusion

The middle ear pressure changes detected in vivo during BET can be attributed to the balloon inflation. Further human studies with patients affected by OETD are necessary to gain more insight into the mechanism of action of BET to clarify a possible pressure related second mechanism of action of BET.