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Biomedical subjects

B H Britton

Publications and source records attributed to B H Britton.

31 records · Page 2Linked to original sources

Carcinoma of the external auditory canal.

Successful management of carcinoma of the external auditory canal depends upon four factors: 1. early diagnosis is imperative if a high cure rate is to be expected; 2. correct evaluation of the extent of the malignancy; 3. adequate surgery based upon correct evaluation; and 4. postoperative radiation in certain selected cases. In this review of 35 cases, two factors were used to determine whether the disease was localized or extensive. When extension occurs inot the mastoid as deep as the middle ear cleft or into the facial nerve, it should be designated as extensive tumor. Tumors which do no go as deep as the facial nerve or involve the mucosa of the middle ear should be designated as localized tumors. In localized tumors, it is possible to perform a wide en bloc resection of the bony and cartilaginous external auditory canal including the tympanic membrane and malleus, and if necessary, including the superficial lobe of the parotid. Postoperative radiation is indicated when the pathological specimen shows unclear margins in the surgical dissection. With localized tumors, en bloc resection of the external auditory canal offers a high cure rate. In extensive lesions, an en bloc dissection removing the bulk of the tumor mass, followed by irradiation, seems to offer at least as good a prognosis as more radical surgery.

Adenocarcinoma↗

Microscopic characteristics of the acoustic tumor in relationship of its nerve of origin.

The microscopic characteristics of a 0.9 cm vestibular schwannoma en bloc resected with its nerve of origin which occurred in a 54-year-old white woman presenting with a two-year history of a unilateral progressive sensori-neural hearing loss is described. The tumor originated in the inferior vestibular portion of the vestibular division of the VIIIth cranial nerve just medial to the internal auditory canal meatus at approximately the level of the glial-non-glial junction. The tumor demonstrated two distinctly different, yet simultaneous, modes of involvement with its nerve of origin: 1. inseparable cellular continuity; and 2. peripheral compression of the remainder of the nerve within the tumor capsule. Despite only slight microscopic continuity of the nerve histologically, electronystagmography showed no unilateral weakness on bithermal caloric testing, and pure tone and speech audiometry was only moderately depressed.

Audiometry↗

Time course of eye nystagmus and body movement after peripheral vestibular lesions in guinea pigs.

Body movement of guinea pigs was measured using a force platform at various times before and after unilateral end organ ablation and before and after sham surgery. Both spontaneous and drop-evoked movement patterns differed in the same animal after vestibular ablation and from control animals that received sham lesions. Whereas measures of eye nystagmus disappeared by 48 h postablation, measures of body movement indicated persistent differences even at 72 h. We conclude that the force platform can differentiate between movement patterns of normal and vestibular-lesioned animals and, in fact, measures a vestibular deficiency that is independent of eye nystagmus. The force platform appears to be a useful addition to evaluate vestibular deficits as well as to detect any benefits of pharmacological or surgical therapies.

Analysis of Variance↗