Monitoring fracture site properties with external fixation

An in-vitro system has been devised to monitor the properties of an idealized fracture site immobilized with a Hoffman-Vidal external fixator. A dial gage was used to measure the relative pin displacements under controlled axial loading. The displacement measurements were then used in conjunction with a finite element model to predict the modulus of an idealized fracture site. Five fracture sites made of neoprene disks of different mechanical properties were monitored in order to simulate the increasing modulus of a healing fracture. Good agreement was observed between directly measured mechanical properties of the neoprene and those inferred from the combined finite element and pin displacement tests.     

Perilymphatic fistula and its interest to audiologists

Forty-one patients who had sudden hearing loss associated with spontaneous perilymphatic fistllas were reviewed in this investigation. A history of physical exertion or an upper respiratory infection prior to the onset of hearing loss strongly suggests the presence of spontaneous perilymphatic fistula. However, absence of such a history does not necessarily preclude the possibility of membrane rupture. A great variation in audiologic and vestibular findings was observed. Tinnitus was present for most patients and vertigo or disequilibrium was reported by some. Findings support the need for surgical exploration in patients with sudden hearing loss when a perilymphatic fistula is suspected. Postoperative success in restoring hearing function in cases with perilymphatic fistula is good if the fistula is closed within two weeks after the initial insult. Delay in closure of such fistulas can cause irreversible loss of hearing.     

Free nor-adrenaline and adrenaline excretion in relation to complications in acute myocardial infarction

The authors report on the clinical data, operating technique, postoperative complications, and late results in a series of 31 epidermoid and 21 dermoid cysts of the central nervous system.