Do magnesium infusions protect the inner ear during middle ear surgery? A randomized double blind study.

Joachims et al. recently demonstrated that magnesium was able to protect the inner ear during exposure to noise and fire arms. During middle ear surgery, the inner ear is subjected to noise from fraising and drilling. We saw fit, therefore, to conduct a random double blind study to establish whether magnesium infusions would protect the inner ear during middle ear surgery. We examined 80 patients (38 verum, 42 placebo). The verum patients received 10 mg/kg body weight magnesium 12 hours and 1 hour prior to operation. Plasma and red cell magnesium levels were measured pre-operatively and intra-operatively; they rose as expected. Post-operative auditory tests showed that magnesium had no tendency to prevent inner ear damage. Advocates of magnesium criticize the limited number of patients in our study as well as the administration of the magnesium substitute. In our opinion, however, it should be borne in mind when evaluating these findings that noise from drilling and fraising is only one factor among many which can induce inner ear injury during middle ear surgery.

[The effect of noise trauma on speech discrimination in silence and under influence of party noise (author's transl)]. / Die Auswirkungen von Knallschäden auf das Sprachgehör in Ruhe und bei Nebengeräuschen unter Berücksichtigung von Schweregrad der Schäden und Alter der Probanden.

Speech audiometry investigations were carried out in silence and under action of cocktail party noise in 44 soldiers. The testing subjects were grouped according to age and degree of noise lesion. The statistical evaluation of discrimination losses measured in silence and under acting party noise indicated that noise lesions induced considerable discrimination losses even in young subjects particularly under cocktail party noise conditions. Discrimination decreases significantly as the degree of noise trauma increases. In order to assess the real effect of the hearing loss caused by noise trauma upon speech discrimination, the tests of speech audiometry should be performed under noise conditions.