P. Bretlau

Enzymatic concept of otospongiosis and cochlear otospongiosis

Parallel anatompathological and enzymatic research led to the discovery of the role played by histiocytes, actively engaged in the lytic process and containing numerous lysosomes, and thus to postulate a cellular and enzymatic concept of otospongiosis. The enzymatic experiments were continued by mico-electrophoresis and allowed the authors to confirm this enzymatic action. In a third step, specific micro-concentrations of trypsin and alpha-1 antitrypsin correlated with cochlear progression, and showed an identical sudden reversal of activity. It was deduced that, when the balance of trypsinlantitrypsin is upset, cochlear deterioration can occur. Confirmation of this concept was done by experimental cytologic findings by scanning electron microscopy. Alteration or destruction of hair cells were the proof of the toxicity of the trypsin action on the inner ear, chiefly on the outer hair cells. The upset of the equilibrium of trypsin and antitrypsin in otospongiotic microfoci and resulting spreading of enzymes from the microfoci into different parts of the cochlea, provokes the peculiar response of the otic capsule with various clinical expressions according to the localization of the impairment: a clinical, stapedial one, resulting in conductive hearing loss; a cochlear one, leading to a sensorineural deafness; a vestibular one, provoking dizziness or even vertigo. The relationship of this enzymatic concept with the disease is explained in detail and leads the authors to express genetic prospects and possibilities of treatment by enzymatic inhibitors.

Sodium fluoride therapy

As a medical treatment for otospongiosis-otosclerosis, sodium fluoride influences the underlying bony changes in the labyrinth so as to arrest or prevent the onset of hearing loss. Sodium fluoride is an enzyme inhibitor and reduces osteoclastic bone resorption and, if the dosage is more than 60 mg a day, may rebuild pseudohaversian bone.

BONE RESORPTION IN OTOSPONGIOSIS

Considerable interest has been raised in recent years concerning the basic mechanisms involved in bone destruction and rebuilding in the otospongiotic focus. Under general bone resorption the osteoclasts play a decisive role, but in otospongiotic tissue electron-microscopic and cytochemical studies have shown that osteoclasts alone are not responsible for the bone resorption. Mononuclear histiocytes found in the marrow spaces and in the surrounding bone of an otospongiotic focus together with osteocytes take active part in the resorption. Cytochemical studies of acid phosphatase activity have shown that hydrolases in the lysosomes are expelled into the surrounding tissue, resulting in its resorption.

Otospongiosis: morphologic and microchemical investigation after NaF-treatment.

Element analysis of microareas of otospongiotic specimens is described. A total of 36 otospongiotic stapes are ultrasectioned without decalcification and examined using a transmission and a scanning electron microscope (STEM-mode). The latter was equipped with an energy dispersive x-ray analyzer. Twenty of the stapes came from patients who have had sodium fluoride (NaF) treatment (15 to 45 mg/day) for a minimum of 12 months. The otospongiotic stapes are classified as spongiotic and sclerotic according to their pathologic characteristics and state of mineralization. Using the Ca/P ratio as criterion—measured by the characteristic x-ray fluorescence—it was shown in a blind study that the NaF-treated otospongiotic stapes had a statistically higher Ca/P ratio, indicating that the fluoride may stabilize otospongiotic lesions, particularly the spongiotic type with unstable mineralization.

Experimental Studies of Cholesteatomas

A model for studying different aspects of human cholesteatomas in vivo in the immunodeficient “nude” mouse is described. Epithelial-mesenchymal interaction was studied in human cholesteatoma membranes, transplanted to the flank region. Findings of cystic lesions lined by stratified keratinizing epithelium were frequent, and the connective tissue reaction was weak. Furthermore, human cholesteatoma membranes were transplanted into the middle ear cavity of “nude” mice. After 21-28 days, bone resorption was found in the labyrinthine capsule, but not always with signs of inflammation.

PLACEBO EFFECT IN SURGERY FOR MENIERE??S DISEASE: NINE-YEAR FOLLOW-UP

: A 9-year follow-up report of our study on endolymphatic shunt procedure versus mastoidectomy is presented. Success has been maintained in about 70% of the patients in both groups and no significant differences between the two groups have been found.

Neoglottic Reconstruction A.M. Staffieri after Total Laryngectomy

22 patients have been operated on with a neoglottic reconstruction a.m. Staffieri after total laryngectomy (tracheo-hypopharyngeal fistula). Only 33 % of the patients had success with a good or acceptable voice and no aspiration). A critical review is given of this surgical procedure.