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Biomedical subjects

M Portmann

Publications and source records attributed to M Portmann.

At least 55 records · Page 3Linked to original sources
PubMed1987

The Portmann procedure after sixty years.

This article recalls the technique described by Georges Portmann in 1926 for the opening of the endolymphatic sac in cases of Meniere's disease. Criteria of indication used at the time are critically analyzed. Modifications of the original operation proposed by various authors, particularly those of T. Naito, W. House, A.W. Morrison, and I.K. Arenberg, are then described. Finally, the current technique and indication criteria implemented in Bordeaux are analyzed, with stress on electrocochleographic determination of the summation potential and its disappearance under the effect of glycerol. According to the author, these latest examination techniques contribute to improving results by providing a better selection of cases likely to be treated by the opening of the endolymphatic sac.

Ear, Inner↗
PubMed1986

Ceravital in ossiculoplasty: experimental studies and early clinical results.

The biocompatibility of the bioactive glass-ceramic Ceravital was investigated experimentally both in vivo and in vitro. In the former, ceramic discs were interposed in 30 rat middle ears for periods ranging from 6 weeks to 12 months. In the latter, Ceravital otological prosthesis were placed in human fibroblast culture. Reactions to the biomaterial were assessed by means of scanning electron microscopy (SEM) with chemical analysis facilities (EDAX, WDAX) and light microscopy. The interface reactions were similar in both in vivo and in vitro studies and confirmed the findings of other authors regarding the implants' biocompatibility and bioactivity. The technique of ion etching, however, enabled clear demonstration of this bioactivity on the implant surface, exposed merely to the middle-ear secretions, thus questioning the necessity of placing bone pâté on the implant head at surgery, in order to encourage bioactive bonding with the overlying drum. A clinical trial of Ceravital in 128 patients with an average follow-up period of 2 years is reported. Forty per cent of these patients underwent a type II tympanoplasty, 60 per cent a type III. Though relatively short-term, the results to date have been encouraging: 88 per cent of the implants have been well-tolerated; 70 per cent of the cases have yielded a satisfactory hearing result; and only 3 per cent of the implanted prostheses have been extruded.

Animals↗
PubMed1986

Experimental and clinical aspects of carbon as a middle ear prosthesis.

The biocompatibility of vitreous carbon and carbon fibre reinforced carbon (CFRC) as middle ear implants was investigated. In separate animal model systems, vitreous carbon was implanted in the middle ear of 20 DA rats for up to 6 months, whilst 3 varieties of CFRC (basic or crude, ultrasonically cleaned, glazed) were implanted in 98 guinea-pig middle ears for up to 4 months. Tissue reactions to implantation were assessed by means of stereoscopic and standard light microscopy, and scanning electron microscopy with chemical analysis facilities (EDAX, WDAX). Vitreous carbon and glazed CFRC were considered suitable for human implantation and a trial of the latter was started in 23 patients (14 partial, 9 total ossicular implants). At 9 months, only 52% of the implants were still in situ; 40% had been extruded and 8% had elicited inflammatory responses which would undoubtedly result in extrusion. Carbon particle dissemination with carbon fibre destruction and exposure as a result of peroperative prosthesis drilling were considered the likely causes for the failure of this implant.

Animals↗
PubMed1986

Extracochlear implants.

A unichannel extracochlear implant designed and made in our laboratory was tried on several patients. Results to date are very similar in all cases. Very rudimentary auditory information is provided, which can help totally deaf patients.

Cochlear Implants↗