Eimoto Hamada

Otitis Media with Effusion and Eustachian Tube Dysfunction in Adults and Children

Eustachian tube (ET) function was studied in 162 ears with otitis media with effusion (OME) and chronic otitis media (COM), using tubo-tympanoaerodynamic graphy, patency and pressure equilibration test in the inflation-deflation test. Severe impairment of active opening function was found in both OME children and adults compared with that of COM patients. This impairment in active opening was thought to result from functional obstruction of the ET in 71.8% of OME children and 51.8% of OME adults. However, 45.6% of OME adults had an organic obstruction while such was present only in 28.2% of OME children. We deduce from this study that impaired active opening function of the ET in both OME children and adults is the result of functional obstruction rather than organic obstruction, but organic obstruction is considered to be related to the pathogenesis of OME in adults.

Eustachian Tube Function Tests and their Diagnostic Potential in Normal and Diseased Ears

We have summarized various methods for testing Eustachian tube function since the 1980s. There have been numerous contributions to our knowledge on Eustachian tube and middle ear functions, and the pathophysiology of disorders of the middle ear has been clarified. Understanding of the Eustachian tube function and controlling the Eustachian tube dysfunction are mandatory for adequate clinical management and for improvement of the prognosis.

Active opening function of the human eustachian tube: comparison between sonotubometry and pressure equilibration test.

Sonotubometry and pressure equilibration test are representative test methods to evaluate the active opening capacity of the Eustachian tube. We applied these tests to 72 ears with otitis media with effusion and 21 ears with chronic otitis media. In 73 ears, both tests showed identical results (11 ears with good active function and 62 ears with poor function). Twenty ears showed good active opening by sonotubometry despite inability to relieve applied negative pressure by swallowing. This inconsistency is believed to result from a too short duration of the tubal opening, by which sound is transmitted through the Eustachian tube, without pressure change in the middle ear cavity. We propose that sonotubometry is a suitable method of detecting impairment of the tubal active opening function, but that a good result by sonotubometry does not always indicate a satisfactory pressure equilibration capacity of the Eustachian tube.

Sensation of Ear Fullness Caused by Eustachian Tube Dysfunctions

One hundred and ninety-four patients with a sensation of ear fullness were examined with the audiometry, tympanometry, and tubotympanoaero-dynamic graphy (TTAG) as a eustachian tube ventilatory test. In 74 cases of 194, the eustachian tube dysfunction was thought to cause an ear fullness sensation and patulous tube was found in 19 patients which is more frequent than expected. Functional unbalance of the both eustachian tubes which results from minimum ventilatory disturbance on the complaining side was also thought to be one of the causes of this symptom. The eustachian tube dysfunctions like stenotic or patulous tube could not be fully diagnosed by the audiometry and tympanometry because most patients with the eustachian tube dysfunctions showed normal middle ear pressure measured by the tympanometry. From our study, it could be concluded that eustachian ventilatory test like TTAG was very available in the patient with an ear fullness feeling which is one of the most common symptoms in the otolaryngological field.

Effect of adenoidectomy on eustachian tube function.

Adenoid vegetation has been considered to be one of the possible causes of otitis media with effusion (OME). Judging from endoscopic findings of the nasopharynx of children with OME, mechanical compression of the adenoid against the pharyngeal orifice of the Eustachian tube appears to result in dysfunction of the tube. However, accumulated clinical experience has revealed that adenoidectomy is not always effective for OME. In this study an attempt was made to assess the effect of adenoidectomy upon the Eustachian tube and middle ear function in children with OME. First, the effect of adenoidectomy on hearing was evaluated in comparison with other combined surgical procedures such as insertion of a ventilating tube and myringotomy. Second, the influence of adenoidectomy on the ventilatory function of the Eustachian tube was examined before and immediately after adenoidectomy.

Animal model of otitis media with effusion

A rat model of otitis media with effusion (OME) was developed by intratympanic injection of E. coli endotoxin and section of the third branch of the trigeminal nerve (V3). The period of fluid retention induced by the endotoxin was prolonged for 5 days or longer, in cases when tubal function was impaired by cutting of V3. Three Eustachian tube function tests (patency test of inflation-deflation tests, forced response test and negative pressure test) were carried out before and after the endotoxin inoculation and V3 sectioning. At 4 days after these procedures, passive opening pressure (Po), closing pressure (Pc) and tubal resistance (R2) were significantly lowered. The negative pressure test showed impaired capacity of active opening. This model of Eustachian tube dysfunction is considered to reveal functional obstruction, a condition similar to that of clinical cases of OME. The study shows that both inflammation in the middle ear and tubal dysfunction, such as functional obstruction, are factors in the development and prolongation of OME.

Passive Opening Function of the Eustachian Tube in Middle Ear Diseases.

Passive opening pressure in various middle ear diseases were measured with three different ventilatory tests (catheter insuffiation, Valsalvas maneuver and inflation-deflation test). The organic status of the Eustachian tube could be divided into four types: normal, stenotic, patulous and pharyngeal stenotic. The pharyngeal stenotic type was found in half of the patients with otitis media with effusion and in 37.5% of those with adhesive otitis media. In this organic change of the tube, the tube does not dilate with swallowing, because the M. tensor veli palatini is not located in the pharyngeal part of the tube. The pharyngeal stenotic type is thought to be one of the causes of disturbed active ventilation of the middle ear and to play an important role in the pathogenesis of otitis media with effusion and of adhesive otitis media.

Experimental Studies on Eustachian Tube Function in Otitis Media with Effusion.

The pathogenesis of otitis media with effusion (OME) in relation to eustachian tube function was investigated in rats.First, the passive function of the eustachian tube was examined by the inflation-deflation test and the forced response test in experimental OME induced by the intratympanic injection of E. coli endotoxin (ET). Before injection passive opening pressure (Po) was 292.1±64.7 mmH2O, closing pressure (Pc) was 184.5±49.1 mmH2O, tubal resistance (R2) was 85.8±23.7 mmH2O/ml/min. OME persisted for up to 2 days. On the day after inoculation Po, Pc, and R2 were significantly higher than before.Second, the third branch of the trigeminal nerve (V3), which supplies the tensor veli palatini muscle (TVPM), was cut and the four eustachian tube function tests were repeated. The three passive tubal ventilatory tests (inflation-deflation, forced response, and eustachian tube function in a pressure chamber) showed that Po, Pc, and R2 were significantly lower than before the nerve was cut; the negative pressure test indicated that negative middle ear pressure was not released even by swallowing. This dysfunctional eustachian tube model is considered to represent the compliant tube (floppy tube), which is characterized by low middle ear pressure for passive opening and functional obstruction under negative middle ear pressure.Third, three eustachian tube function tests (inflation-deflation, forced response, and negative pressure) were performed after ET inoculation and V3 section. Middle ear effusion was observed for 5 days or longer in all the rats. Compliant tube features were seen on the fourth day, and they persisted even after the effusion cleared.In conclusion, these experimental studies indicate that both inflammation and tubal dysfunction are probably important factors in the pathogenesis of OME.

Measurement of middle ear ventilation with xenon gas - Normal subjects.

The ventilation and clearance of the middle ear were measured by radioisotope imaging techniques in order to gain a clear picture of the mechanism of ventilation. Radioactive xenon gas was insufhated into the middle ear of 9 normal subjects via the Eustachian tube, and observed by scinti camera. The volume was calculated with the passage of time. Approximately 11% of the insufflated gas immediately entered into the middle ear cavity and mastoid air cells in spite of the fact that the middle ear and mastoid air cells are a closed cavity. The gas in the middle ear diminished at a rate of 6% of volume per hour and it was thought to be absorbed mainly into the middle ear mucosa at a regular rate in the resting state.

Effect of adenoidectomy on Eustachian tube function of children with otitis media with effusion.

To evaluate the effect of adenoidectomy on Eustachian tube function, opening pressure was measured before and immediately after adenoidectomy and every month for 5 months in 10 children, and the inflation-deflation test was performed every month for 6 months after the insertion of tympanostomy tubes in 42 children.The following results were obtained: 1) opening pressure decreased immedeately after adenoidectomy in about half of the children, 2) inflation-deflation test results did not improve after adenoidectomy, at least for 6 months, 3) children with adenoid hypertrophy failed to respond to the inflation-deflation test at all, while 20% of the children treated with adenoidectomy showed a positive response to the test. One can conclude that children with adenoid hypertrophy should be treated with adenoidectomy.