Neurosurgery
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Electric stimulation of the dorsal spinal cord (DCS) in the treatment of pain in peripheral vascular disease is known to enhance peripheral circulation, but the mechanisms are still obscure. An earlier study has provided indirect evidence that the vasodilator effect is dependent upon alteration of sympathetic vasomotor activity. In the present study, surgical interruption of sympathetic pathways was performed to define the role of the sympathetic system for the stimulation-induced vasodilation. ⋯ DCS with clinical parameters did not produce this reciprocity in the control and sham-operated rats, but induced a vasodilation in both skin and muscle. After complete sympathectomy, defined as postoperative disappearance of the vasomotor responses to cold, the vasodilation in skin and muscle in response to DCS was abolished; however, the vasodilatory response to high-intensity stimulation (approximately 10 times the motor threshold) was not affected. Incomplete sympathetic denervation in some animals resulted in partial preservation of a vasodilatory response to DCS.(ABSTRACT TRUNCATED AT 250 WORDS)
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The vertebral arteries appear to be particularly susceptible to injury in trauma of the cervical spine because of their close anatomical relationship to the spine; however, traumatic subintimal dissection of the vertebral artery is rare judging from the paucity of cases reported in the literature. The case of a patient who developed a visual field defect secondary to a fracture-subluxation of the cervical spine is reported. Angiography demonstrated an intimal dissection of the vertebral artery at the site of the fracture-subluxation resulting in thrombus formation and subsequently in emboli occluding the posterior temporal branch of the posterior cerebral artery. Early angiography is recommended if extracranial injury of the vertebral artery is suspected, and the institution of heparin therapy is necessary if a subintimal dissection is demonstrated.
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The authors review their experience with a dorsolateral approach to the anterior rim of the foramen magnum and adjacent region. The operative technique includes exposure of the vertebral artery at C1, partial resection of the occipital condyle and lateral atlantal mass, and extradural drilling of the jugular tubercle. ⋯ No morbidity and no mortality were associated with this approach. The main advantage of the dorsolateral, suboccipital, transcondylar route is the direct view it offers to the anterior rim of the foramen magnum without requiring brain stem retraction.