Neurosurgery
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Recent reports have suggested that peripheral neurectomy with the CO2 laser may be effective in preventing subsequent neuroma formation. To study this question further, we performed bilateral sciatic nerve sections in 31 rats using a steel scalpel on one nerve and a CO2 laser on the opposite side. The animals were killed 30 days after neurectomy and specimens were removed for gross observation, light microscopy, and electron microscopy. ⋯ Analysis of axon composition studies revealed that both neuromas had a greater density of axons and a higher percentage of small diameter myelinated and unmyelinated axons as compared to control nerves. Laser neuromas had more axons per unit area than scalpel neuromas, but the percentage composition of axons was very similar in the two groups. We could find no evidence in the rat sciatic nerve model that CO2 laser neurectomy is less likely to result in neuroma formation than is conventional scalpel neurectomy.
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Six patients representing seven cases of spontaneous (nontraumatic) saphenous neuralgia secondary to entrapment of the nerve in the subsartorial canal are presented. All patients complained of medial knee and leg pain. Clinical findings included tenderness over the subsartorial canal and sensory changes in the cutaneous distribution of one or both terminal branches of the saphenous nerve. ⋯ All patients were treated operatively, which resulted in symptomatic improvement. All six patients initially underwent external neurolysis; however, three patients required saphenous neurectomy for recurrent symptoms. Saphenous neuralgia should be considered in the differential diagnosis of medial lower extremity pain.
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We studied 61 patients with a closed head injury and increased intracranial pressure (ICP). The ICP was monitored continuously, concomitant with the administration of 20% mannitol. ⋯ The level of the ICP measurements and the cumulative amount of preceding doses of mannitol influenced the response of ICP to mannitol more than did the size of the dose of mannitol. These findings imply that: (a) the initial administration of more mannitol than is absolutely needed may lead to larger doses being required to control ICP and (b) for that reason, mannitol given on a gram/kilogram, an hourly, or a serum osmolarity basis to control increased ICP has negative long term effects because more mannitol may be required to decrease ICP when an excessive amount of it has been given previously.