To determine the relation between local myofiber anatomy and local deformation in the wall of the left ventricle, both three-dimensional transmural deformation and myofiber orientation were examined in the anterior free wall of seven canine left ventricles. Deformation was measured by imaging columns of implanted radiopaque markers with high-speed, biplane cineradiography (16 mm, 120 frames/sec). Hearts were fixed at end diastole and sectioned parallel to the local epicardial tangent plane to determine the transmural distribution of fiber directions at the site of strain measurement. The principal direction of deformation associated with the greatest shortening was compared with the local fiber direction in the outer (21 ± 8 % of the wall thickness from the epicardium) and inner (65 ±9%) halves of the wall. Although the fiber direction varied substantially with depth from the epicardium, the principal direction did not. In the outer half of the wall, fiber direction averaged-8 ± 24°, while the principal direction averaged-33 ±24° from circumferential (counterclockwise angles are positive). In the inner half, fiber direction averaged 69 ±10°, while the principal direction averaged-22 ±21°. Therefore, while fiber and principal directions were not substantially different hi the outer half, the greatest shortening occurred orthogonally to the fiber direction hi the inner half. Normal and shear strains measured in a cardiac coordinate system (circumferential, longitudinal, and radial coordinates) were rotated (transformed) to "fiber" coordinates hi both halves of the wall. In the outer half, normal strains observed in the fiber (-0.09 ±0.04) and cross-fiber (-0. 0 4 ±0.04) directions were not significantly different (paired t test, p<0.05). In the inner half, more than twice as much strain occurred in the cross-fiber (-0.17 ± 0.03) than in the fiber direction (-0.06 ± 0.06). Moreover, the only shear strain that remained substantial after transformation was transverse shear in the plane of the fiber and radial coordinates. These results suggest that both reorientation and cross-sectional shape changes of myofibers or the interstitium may contribute to the large wall thickenings observed during contraction, particularly in the inner hah* of the ventricular wall. (Circulation Research 1988;63:550-562) T he way in which myofibers lying at different depths in the heart wall and having different orientations interact during contraction is not known. It is well known, however, that there is an extensive collagenous network surrounding the myocyte and collagen struts between myocytes. 12 Moreover, the direction of the myofibers, which varies continuously with depth spanning more than 100° across the anterior free wall of the canine left ventricle, 34 is neither altered by large changes in ventricular mass or shape 3 nor affected greatly by

The improved survival of patients sustaining massive head injuries has increased the number of temporal bone fractures being managed by otolaryngologists and neurosurgeons. We performed a prospective analysis of 35 patients with head injury with temporal bone trauma. The major emphasis of this study was to investigate the incidence, management, and outcome of facial nerve injury in such patients and to evaluate the importance of electrodiagnostics in the surgical management of the facial nerve. The results of this study indicate an incidence of fracture type, hearing loss, and facial nerve paralysis similar to that already recorded in the literature. This study underscores the importance of evoked electromyography, or electroneuronography, in assessing facial nerve function. Electroneuronography provided the indications for surgical intervention for facial paralysis. All patients having surgery for facial paralysis as determined by electroneuronographic findings had pathology of the facial nerve.

Parotid surgery often leaves a facial contour deformity. Free abdominal dermal-fat grafts were used to preserve the facial contour of nine patients undergoing parotid surgery. This procedure is simple to perform and provides an improved cosmetic result without significantly increasing operative time or lengthening hospitalization. No troublesome fat absorption occurred postoperatively. The dermal-fat graft also serves as a barrier to regenerating neurons, thereby preventing postoperative gustatory sweating.

The risk of perioperative strokes has been demonstrated to be very low in general surgical procedures, and somewhat higher in cardiac and carotid artery procedures. We describe 5 patients who underwent major head and neck procedures not requiring carotid ligation and who postoperatively suffered strokes. These occurred between the first and ninth postoperative days. Four of the patients were thought to have had emboli, 3 to the cerebral hemispheres (2 ipsilateral and 1 contralateral to the neck dissections), and another to the lower brain stem. Hypoperfusion was thought to have caused the stroke in the fifth patient. All patients had risk factors for stroke. The cases in our series were difficult to diagnose because of the delayed onset and subtle nature of symptoms, as well as masking of speech and communication due to the operative involved. Thrombogenesis within the internal carotid and vertebral artery systems due to patient positioning and intraoperative cervical manipulation may be an important etiologic factor in this form of stroke.

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The improved survival of patients sustaining massive head injuries has increased the number of temporal bone fractures being managed by otolaryngologists and neurosurgeons. We performed a prospective analysis of 35 patients with head injury with temporal bone trauma. The major emphasis of this study was to investigate the incidence, management, and outcome of facial nerve injury in such patients and to evaluate the importance of electrodiagnostics in the surgical management of the facial nerve. The results of this study indicate an incidence of fracture type, hearing loss, and facial nerve paralysis similar to that already recorded in the literature. This study underscores the importance of evoked electromyography, or electroneuronography, in assessing facial nerve function. Electroneuronography provided the indications for surgical intervention for facial paralysis. All patients having surgery for facial paralysis as determined by electroneuronographic findings had pathology of the facial nerve. (Otolaryngol Head Neck Surg 1997;117:67–71.)

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