Biomedical subjects
Publications and source records attributed to J R Causse.
The authors present here the usually less developed complications of stapedectomies: postoperative cochlear drops, tinnitus, vertigo. They also mention the other complications of stapedial surgery. They insist particularly on the interest of half posterior platinectomy technique, associated with a sufficiently large venous interposition.
Extensive research on enzymes led to the discovery of the innermost mechanism of the otospongiotic disease. The authors present the results of multiple correlations made from February 1976 to September 1980 on 648 samples of perilymph taken during stapedectomies performed on otosclerotic patients. We studied microdosages of three selected enzymes--trypsin, alpha 1 antitrypsin, and alpha 2 macroglobulin--in each of the samples and their relationship with cochlear deterioration expressed in dBs of bone conduction decrease in pure-tone audiometry testing. This study allowed us a better knowledge of the enzymatic mechanism of the otospongiotic disease, based on the previously reported trypsin-alpha 1 antitrypsin balance, but in which alpha 2 macroglobulin appears to play a role as essential as that of alpha 1 antitrypsin. This enzymatic mechanism explains NaF efficiency, which is due in fact to a double action: not only direct trypsin inhibition, but also an overall reduction in enzymatic values in the perilymph of otospongiotic/otosclerotic patients. Current studies could lead to the possibility of future NaF replacement by proteinase inhibitors either of microbial origin, under study by Japanese researchers, or even of synthetic origin, which should be investigated. In fact, the role of NaF therapy could already be taken over by diphosphonates currently under study.
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The authors present the conclusions they reached after more than four years of multiple correlations made from february 1976 to september 1980. 648 perilymph samples were selected from a total number of 811 samples taken during stapedectomies on otosclerotic patients. These multiple correlations were based on micro-dosages of three selected enzymes (trypsin-alpha 1 antitrypsin and alpha 2 macroglobulin, the fourth cathepsin B having not been found, even in perilymph pools) in each of the selected samples, and on their relationship with the cochlear deterioration expressed in dBs of B.C. decrease and in audiometric stages corrected with reference to the patients' age. This study leads to an enzymatic mechanism, based on the previously reported trypsin-alpha 1 antitrypsin balance, but in which alpha 2 macroglobulin appears to play as essential a role as that of alpha 1 A. This enzymatic mechanism explains NaF efficiency, due in fact to a double action, not only to direct trypsin inhibition, but also to an overall reduction in enzymatic levels in the perilymph of otosclerotic patients. The authors conclude by suggesting the possibility of future NaF replacement by proteinase inhibitors, either of microbial origin currently under study by Japanese researchers, or even of synthetic origin.
This study of a possible relationship between the ABG and the remodeling of the niche in otosclerosis in a significant number of patients operated on by stapedectomy allows the authors to define six types of ABG shape, corresponding to various types of stapedial fixation and remodeling of the niche. But the difficulties in finding the real bone conduction threshold levels, which ABG shapes depend on, lead us first to explain the mechanism of the various dips and notches altering bone conduction curves; and second, to try to find a safe and sure method for precise evaluation of the real cochlear reserve in otospongiosis/otosclerosis. We conclude that the best method is the bone conduction speech audiometry, mainly the bone conduction speech Weber tes, which automatically shows the true cochlear reserve of the ear to be operated on.
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This presentation discusses the most valuable way to correlate specific morphologic changes in cochlear otospongiosis with sensorineural hearing loss. Both biochemical and vascular factors may be responsible for the association of far advanced otospongiosis and histopathologic changes. An enzymatic concept of the disease is proposed on the basis of experimental findings and cytoclinical correlations, and the spread of proteolytic enzymes from the bursting lysosomes in histiocytes of the otospongiotic microfoci of the lateral wall. In addition, according to Ruedi's vascular concept, abnormal vascular connections called "shunts", provoked by active foci breakiny oxygen. Such extensive otospongiotic bone transformation breaking the endosteum of the cochlear is much less frequent than the progressive cochlear component encountered by otologic surgeons in far advanced otospongiosis. It is for this reason that the authors believe that their enzymatic concept of otospongiosis may explain the most important part of the sensorineural impairment in cochlear otospongiosis.
Previous studies by the Adams method demonstrated a strong correlation between hydrolytic enzyme activity of perilymph and progression of bone conduction loss two years preceding stapedectomy. Alpha 1-Antitrypsin was chosen since its activity can be very precisely measured by a radical immunodiffusion technique and since it is one of the enzymes identified in perilymph of patients with active otospongiosis. Samples of 3 mul to 5 mul of perilymph removed during 103 stapedectomies and samples of known alpha 1-trypsin activity were placed on slides coated with alpha 1-antitrypsin serum. The zone of diffusion was stained and measured after 38 hours of incubation. Antitrypsin values were lowest in 24 cases, two with no preoperative bone conduction progression, three with moderate progression of 10 to 15 dB, and 19 with rapid progression of more than 20 dB. They were highest in 36 cases with no progression, and in one case with moderate progression. This study confirms previous reports on the enzymatic activity in otospongiotic disease.
The 'fistula test' is performed when an abnormal opening between the vestibule and the middle ear cavity is suspected. The fistula is usually seen after stapedectomy, but may also occur after trauma to a normal ear when the round window membrane may rupture. Tympanometry with an electronystagmographic (ENG) tracing may show a positive result after stapedectomy in the absence of a fistula, and there may conversely be a normal ENG tracing after tympanometry when there is in fact a perilymph fistula. The authors explain the reasons for this paradoxical response. In no way does it detract from the value of the test, which only needs to be interpreted correctly.
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Progress in new audiometric techniques, chiefly in impedance-audiometry, and better knowledge of the innermost mechanism of the otospongiotic disease, have led the authors to plan prevention of the otospongiotic disease, which appears to be a genetic deafness with an autosomal dominant inheritance and about 40% penetrance of genes. The bases of this prevention are: first, the early detection of stapedial fixation by means of systematic audiometric investigations, particularly elicitation of the on-off effect by impedance-audiometry; second, the treatment of oto-spongiotic children with very low doses of sodium fluoride without any risk of stunting the growth. The authors have been applying these means for four years to families of stapedectomized otosclerotic patients, but they think that it would be advisable to extend this type of prevention to the systematic detection of otospongiosis in school-children by means of audiometry investigations, including the elicitation of the stapedius reflex in order to detect a possible on-off effect. Moreover, the prescription of a fluoride treatment to otospongiotic mothers for prevention in their new-borns (exactly as in dental prevention), would allow us, with the support of parents and public authorities, to eradicate this severe disease in the near future. Twenty years ago, otospongiosis still seemed incurable, but at present this disease can be very easily controlled by a medical treatment based on enzymogenesis regulators, associated with surgery if needed.