Tubenfunktionspr�fung in der Druckkammer: Registrierung mittels eines differentialmanometers

[The pressure-equalizing function of the Eustachian tube : Evaluation in a hypo-/hyperbaric pressure chamber]

BACKGROUND

The Eustachian tube connects the tympanic cavity (cavum tympani) and the nasopharynx, and enables pressure equalization between the middle ear and ambient pressure. Functional pressure compensation is very important for flying and diving in particular, due to non-physiologically large pressure differences.

OBJECTIVE

Evaluation of the pressure-equalizing function of the Eustachian tube is still a clinical challenge. This review article evaluates the existing data.

METHODS

Based on a selective literature search, different methods for evaluation of tube function are presented and evaluated, with special reference to evaluation of the pressure-equalizing function in a hypo-/hyperbaric pressure chamber.

RESULTS

The pressure chamber enables the dynamics of active and passive pressure compensation to be provoked and also permits accurate measurement of pressures in the millibar range.

CONCLUSION

A pressure chamber seems to be suitable to evaluate Eustachian tube function and therapeutic approaches to tube dysfunction. Further studies are needed to assess the value of the pressure chamber in combination with other functional tests.

The improvement of middle ear ventilation by laser ablation of the epipharyngeal eustachian tube: a prospective study

A long-lasting dysfunction of the eustachian tube seems to be the etiologic origin for development of chronic otitis media (COM) with mesotympanic perforation, otitis media with effusion (OME), and chronic atelectasis of the middle ear. Surgical interventions in the middle ear generally treat the sequelae of the tube dysfunction but not the dysfunction itself. This prospective clinical study investigated how far fiber-guided laser ablation of the posterior half of the epipharyngeal tubal ostium led to better middle ear ventilation in the otologic disease patterns mentioned below. There were 38 adult patients included in the analysis. The patients in one group had a perforated tympanic membrane [COM before primary tympanoplasty (n = 14) or revision tympanoplasty (n = 5)]; the patients in a second group had an intact eardrum [OME resistant to therapy (n = 3), with an atelectasis of the middle ear (n = 2) or problems of pressure equalization with fast changes in ambient pressure (diving, flying) (n = 14)]. Laser ablation of the posterior half of the epipharyngeal tubal ostium was performed, generally with local anesthesia, if tubal function testing was pathologic (Valsalva maneuver, passive tube opening, tympanogram). In patients with COM the procedure was performed 8 weeks before the middle ear surgery. All patients were checked 8 weeks postoperatively and in the course of the following year. The intervention seemed to have had a positive effect on tube function in 68.4% of patients operated on (P = 0.001). In 26 of the 38 patients that had undergone operation, an improvement the results of tubal function tests could be seen in the postoperative follow-up. In the COM group the Valsalva maneuver improved in 14 of 19 patients (73.6%) (P = 0.001), and the passive tube opening improved in nine of 18 patients (50%). In the group with an intact eardrum the Valsalva maneuver improved in 13 of 18 patients (72.2%) (P = 0.001). The resulting condition remained stable after 1 year. None of the patients showed any complications as a result of the therapy. Minimally invasive shaping of the distal eustachian tube under topical anesthesia can be recommended for patients with the above-mentioned diagnoses who have pathologic middle ear ventilation. Especially prior to tympanoplasties, and especially in otologic revision procedures, where middle ear ventilation is a prerequisite for successful otologic surgery, the function of the eustachian tube can be optimized in 70% of the patients, particularly if there are pathological findings (tubal tonsil, narrow orifice of the tubal ostium, adenoids). The placement of permanent ear tubes in adults with recurrent OME can also be avoided by the procedure described. The resultant conditions remained stable for the next year. Patients with tympanic ventilation problems due to rapid pressure changes (flying, diving) can also benefit from this procedure.

Funktionsuntersuchungen der Tuba Eustachii

The Eustachian tube regulates the homeostasis of the middle ear. Problems with its function are predominantly found in childhood. As a consequence, otitis and hearing impairment occur. The most important muscle is the tensor tympani muscle. The complexity of the functional anatomy and physiology are reasons why no function test alone is capable of fulfilling all diagnostic needs. The predictive value of the various Eustachian tube function tests for the outcome of a tympanoplasty is not yet clear. An overview of clinically and scientifically relevant tests for the Eustachian tube function is provided.

Aerodynamic pattern of Eustachian tube dysfunction

Detailed aerodynamic patterns for various disorders of the Eustachian tube function were reported. Simultaneous recording of the pressure in the ear canal and the pharyngeal cavity during Valsalva's maneuver and deglutition permitted an objective evaluation of different tubal dysfunctions. The patient with occluded tube showed either disturbance of the air flowing into the tube or outflowing from the tympanum to the pharynx. Depending on the degree of patency, the patulous tube showed either a synchronous change of the tympanal pressure with that of the pharyngeal cavity or an early and sudden drop of the tympanal pressure without deglutition. Through this rather simple aerodynamic technique, evaluation of different tubal dysfunction is possible.