Articles: peripheral-nerve-injuries.
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We have studied the immediate and long term (up to 28 days) effects of short and long bevelled needle impalement of the rat sciatic nerve. Three techniques were used to assess neural trauma and its consequences: stained longitudinal nerve sections were assessed by light microscopy and scored for injury; the extravasation of Evan's Blue dye, after antidromic electrical nerve stimulation, was used as a test of unmyelinated fibre function; the flexion withdrawal times from a noxious stimulus were measured. ⋯ Nerve injury induced by short bevelled needles was associated with persisting signs of injury 28 days after the injury. These results suggest that the current practice of using short bevelled needles to prevent nerve injury complicating regional anaesthesia be reassessed.
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An elderly female cadaver fore-quarter amputation was dissected, and a custom straight intramedullary nail with a 55 degrees oblique downward lateral to medial proximal screw was inserted with a trocar protruding beyond the medial cortex of the humeral surgical neck. The main trunk of the axillary nerve was found to be at risk with any penetration from anterior to posterior and any screw penetration beyond the medial cortex with internal rotation. ⋯ Transverse screws inserted through the humeral neck from lateral to medial have the potential for damaging a small branch of the axillary nerve laterally, and care must be taken of the lateral humerus while inserting these screws. Screws inserted in a downward direction near the greater tuberosity, if originating above the equator of the humeral head, may cause impingement.
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Neurosurg. Clin. N. Am. · Jan 1991
ReviewAspects on pathophysiology of nerve entrapments and nerve compression injuries.
The microanatomy of the neuron and the peripheral nerve, which is a composite tissue, should be considered when discussing the pathophysiology of nerve compression injuries. Acute and chronic compression of peripheral nerve can induce changes in intraneural microcirculation and nerve fiber structure, increase vascular permeability with subsequent edema formation, and impair anterograde and retrograde axonal transport, which all contribute to the clinical symptoms and deterioration of nerve function. ⋯ Diabetes mellitus may confer on the peripheral nerve an increased susceptibility to compression injuries. Clinical stages of compression syndromes, such as carpal tunnel syndrome, may be related to specific pathophysiologic events occurring in the nerve.
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Acta Orthop Scand Suppl · Jan 1991
ReviewTourniquet-induced neuromuscular injury. A recent review of rabbit and clinical experiments.
A rabbit model was developed which facilitates controlled, experimental studies of tissue injury beneath and distal to a pneumatic tourniquet. Non-uniform tissue deformation was observed beneath inflated tourniquets; such patterns were not predicted by previous mathematical models. Two hours was a time threshold for tourniquet compression injury; depending upon the cuff inflation pressure, greater muscle injury was induced beneath the tourniquet than distal to it. ⋯ In conclusion, tourniquet application, at clinically relevant cuff inflation pressures and durations, induces greater neuromuscular injury beneath the tourniquet than distal to it. Investigators of systemic effects of limb ischemia should be aware of compression injury induced by pneumatic tourniquet models. Surgeons must weigh the advantages of a bloodless field against the disadvantages of tourniquet-induced neuromuscular injury.