Hiroshi Miyashita

Computed tomography of the temporal bone in tuberculous otitis media.

Nine cases of tuberculous otitis media were treated by us over the past 10 years. Six patients presenting with large tympanic membrane perforations were treated for suppurative otitis media at various ENT clinics. The remaining three patients presented without perforation. Intractable otorrhoea, aggravation of hearing loss, dizziness, and in one case facial palsy, resulted in eventual referral to us. Histological examination revealed a tuberculous granulation, confirming the diagnosis in most cases. CT in four cases with profound sensorineural hearing loss showed bone destruction of the otic capsule around the oval window and the promontory. Changes noted included a notch in one case, disappearance of the bony contour around the hook in two cases, and a distinct fistula in the final case. A cochlear fistula seemed to be characteristic of advanced tuberculous otitis media.

Photochemically induced focal cochlear lesions in the guinea pig: II. A transmission electron microscope study.

Photochemically induced focal lesions in guinea pig cochleas were studied by light microscopy and transmission electron microscopy. The lesions were induced in the second cochlear turns of 35 adult guinea pigs by illumination for 10 minutes with a focused green light immediately after a rose bengal solution was injected into the jugular vein. The cochlear lateral wall and organ of Corti were examined 5, 10, 20, 30, and 90 minutes, l2 and 24 hours, and 3, 7, and 30 days after the procedure. Aggregations of platelets and red blood cells were found in strial capillaries at 5 minutes after illumination. After 30 minutes, marginal cell surfaces protruded into the endolymphatic space; surface membranes were ruptured and the cytoplasm was expelled into the space. In outer hair cells, disruption of the cellular membrane was found near the cuticular plate 12 hours after the procedure. All cellular elements of the lateral wall and organ of Corti were markedly degenerated in the 30‐day specimens. Histological changes found in the stria vascularis were consistent with cell damage caused by active oxygen species. It is likely that the stria vascularis is more sensitive to the photochemical reaction than other parts of the cochlea. Cell damage in other parts of the cochlea seemed to have been caused by local microvascular ischemia in addition to the action of active oxygen species induced by the photochemical reaction. Microsc. Res. Tech. 41:334–340, 1998.

Reconstruction of the cervical trachea with a free forearm flap

With the aim of voice restoration after repair of a total defect or obstruction of the cervical trachea, we developed a new method of total cervical tracheal reconstruction with a free forearm flap. The forearm flap is inverted to form a tube and then interposed between the subglottic trachea and an adjacent cutaneous fistula created at the upper portion of the tracheostoma. A permanent tracheostoma is preserved, and an L-shaped silicone tube is inserted in the reconstructed cervical trachea and the tracheostoma as a stent. In two patients, both became able to speak.

Focal Damage to Cochlear Microcirculation Measured using a Non-Contact Laser Blood Flowmeter in Guinea Pigs

The focal microcirculation damage induced by a photochemical reaction in the stria vascularis (SV) of the guinea pig cochlea was evaluated using a non-contact laser blood flowmeter (NCLBF) and the endocochlear potential (EP). Focal degeneration, including vascular thrombosis in the SV produced by the systemic infusion of rose bengal, and the illumination of green light in the second cochlear turn were observed with scanning and transmission electron microscopy. The NCLBF probe was placed at a position 10 mm from the cochlear surface, and the diameter of the laser light was focused to 1 mm in the green light illumination area. The change in NCLBF values induced by the loading of anoxia and administration of epinephrine agreed very well with those obtained with a conventional contact-type laser Doppler flowmeter. Significant decreases in the cochlear blood flow (CBF) (p < 0.01) and EP (p < 0.01) were observed at the site of the photochemical injury compared with the values at the non-illuminated area. CBF gradually decreased (82.0+/-7.3% at 10 min, 71.2+/-5.5% at 20 min, 64.3+/-11.2% at 30 min from the baseline, n=7), but blood pressure was stable. The EP values also decreased gradually during the first 13 min (79.9+/-3.7 mV at pre-illumination, 11.4+/-10.7 mV at 13 min, n=7). The gradual decline in the EP was comparable to the changes in the CBF. The NCLBF was useful for evaluating the haemodynamic properties of the cochlear microcirculation disorders, and this animal model is expected to be suitable for studying the pathology of focal cochlear vascular disease.

Eight Cases of Tuberculosis of the Middle Ear.

Eight cases (10 ears) of tuberculous otitis media are reported. These patients visited our clinic between 1988 and 1989. Seven of the 8 cases were previously treated as chronic otitis media at some other E. N. T. clinics. As five of these 8 cases were once treated in a certain clinic, iatrogenic implanted infection at that clinic was strongly suspected. Characteristic features of the symptoms were remedy-resistant otorrhea, otalgia, progressive hearing loss and facial paralysis. Important local findings for diagnosis were pale granulation tissue covered with thick fibrinoid material and presence of bare bone on the promontory. Combined use of antituberculous medicines, such as isoniazid, ethambutol, rifampicin, was effective for treatment. Although facial paralysis and progressive hearing loss occurred during the use of these medicines in the non-operated group, none of these complications were seen in patients who had had surgery before the use of these medicines. Eradication of the infection by surgery may be preferable in some cases of tuberculous otitis, especially in cases with bone erosion on the CT images.