Regeneration across preserved peripheral nerve grafts.

The potential to store nerve grafts for a prolonged period of time was assessed in a rat sciatic nerve model. Three-centimeter syngeneic nerve grafts were stored in Belzer/University of Wisconsin cold storage solution at different temperatures (5 degrees C, 22 degrees C, or 37 degrees C) for varying time periods (6 h, 24 h, or 3 weeks) prior to transplantation. Functional assessment using serial walking track analyses revealed no difference between storage times and temperatures. At 14 months postengraftment, the conduction velocities and the number of myelinated fibers that had regenerated across all grafts stored at 5 degrees C for all time periods tested were superior to grafts stored at either 22 degrees C or 37 degrees C. Nerve grafts stored for up to 3 weeks at 5 degrees C acted as effective conduits for proximal regenerating fibers and resulted in histologic, electrophysiologic, and functional results equivalent to fresh nerve grafts. Nerve graft storage may be applicable to nerve allografts and potentially provide allograft material that requires reduced or no associated host immunosuppression.

Ligation of the common carotid artery for the management of a mycotic pseudoaneurysm of an extracranial internal carotid artery. A case report and review of the literature.

Although vascular involvement by deep neck space infections occurs very rarely today with the widespread use of antibiotics, they often pose a significant challenge to the modern otolaryngologist, who most likely will have had no previous experience with either the diagnosis or treatment of these potentially life-threatening infections. We describe the case of a young female presenting with fevers, dysphagia, and blood-tinged sputum, who was diagnosed by contrast-enhanced computerized tomography, to possess a mycotic pseudoaneurysm of her right extracranial internal carotid artery, for which ligation of her common carotid artery was required. We also discuss both the clinical findings which should lead one to suspect that a neck infection may be involving the extracranial carotid arteries, and the English literature, on the morbidity and mortality of ligating a common carotid artery.

Skeletal muscle form and function after 4 hr ischemia-hypothermia.

The purpose of this study was to examine the use of hypothermia to protect skeletal muscle from the effects of 4 hr of tourniquet ischemia. Muscle recovery was investigated at 6 weeks. Four hours of tourniquet ischemia was induced in two groups (n = 8 per group) of male, Wistar rats (344 +/- 15 g). In the ischemia-only group (IO), the ischemic leg was exposed to room temperature. In the ischemic-hypothermic group (IH), the ischemic leg was cooled to 5-8 degrees C throughout the ischemic period. The contralateral leg served as control. After 6 weeks, the isometric contractile function of the gastrocnemii of both the ischemic and nonischemic legs was determined. Following the functional assessment, the soleus and plantaris muscles were removed and weighed, and biopsies were taken for muscle fiber composition, mean fiber area, and myosin heavy chains (MHC) analysis. Differences between groups (P < 0.05) were determined using ANOVA. Muscle wet weight, tetanic forces, fiber area, fiber type, and MHC composition of IH group were the same as the control group. Yet, twitch tension and relaxation time were lower and longer in the IH group than control group. The tetanic force at 100 Hz of the IH group (12.62 +/- 0.73 N/g) was significantly greater than that of the IO group (2.12 +/- 0.84 N/g). The type 1 muscle fiber areas of plantaris in the IH (1.84 +/- 0.04 x 1000 microns 2) were significantly greater than those of the IO group (1.56 +/- 0.42 x 1000 microns 2).(ABSTRACT TRUNCATED AT 250 WORDS)

Isometric contractile function following nerve grafting: a study of graft storage.

In order to assess the effects of storage on nerve grafts, the isometric contractile function of the gastrocnemius muscle was assessed 14 months following sciatic nerve autografting in the rat. Three-centimeter sciatic nerve grafts were stored at either 5 degrees C or 22 degrees C for 6 h, 24 h, or 3 weeks in an organ transplant solution. Muscle mass and maximal force in the fresh control graft group returned to 47% and 36% of normal levels, respectively, which was similar to stored grafts. Storage at 5 degrees C was superior to 22 degrees C and there was no decrement in contractile function in grafts stored up to 3 weeks at 5 degrees C. These findings suggest that the storage of nerve grafts is a feasible technique that might be applied to nerve allografts, thus permitting elective reconstruction of large peripheral nerve gaps.