Neurosurgery
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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.
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A new index of cerebral hemodynamics, cerebral hemodynamic reserve (CHR), was evaluated in 12 comatose adults with severe, acute, traumatic, diffuse swelling of the brain, who underwent continuous monitoring with a fiberoptic catheter of the saturation difference in arteriojugular oxyhemoglobin. CHR was assessed as the ratio of changes in global cerebral oxygen extraction to changes in cerebral perfusion pressure (CPP) as a result of spontaneous increases in intracranial pressure (ICP). During the course of hyperventilation (Pco2 in the range of 20 mm Hg) for ICP control below 20 mm Hg, 34 observations were made over the initial 48 hours postinjury. ⋯ This was reflected by the occurrence of baseline normalized cerebral oxygen extraction. It is concluded that in this group of patients, under circumstances of profound hyperventilation, ICP elevations within the normal CPP range may result in decreased cerebral oxygenation, even when the normal CPP would imply otherwise. It is suggested that CHR assessment may provide information regarding the status of intracranial "tightness," insofar as cerebral circulation and oxygenation are concerned.
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A case of the de novo formation of an aneurysm in a young woman is presented. At age 13 years, she had a spontaneous subarachnoid hemorrhage. Cerebral angiography showed an aneurysm of the bifurcation of the left internal carotid artery and a small aneurysm of the left anterior choroidal artery. ⋯ Thirteen years later, the patient had another subarachnoid hemorrhage. Cerebral arteriography showed four aneurysms that had developed at previously angiographically normal sites. This case suggests that young patients with aneurysms might benefit from follow-up angiography in search of late aneurysm formation.
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Case Reports
Spinal cord compression complicating subarachnoid infusion of morphine: case report and laboratory experience.
The intraspinal administration of morphine has been employed increasingly in the management of intractable pain of malignant as well as benign origin. We have encountered a previously unreported clinical complication: spinal cord compression by an inflammatory tissue mass surrounding a subarachnoid infusion catheter administering morphine, leading to paraplegia. The patient was referred to our institution after catheter and pump implantation for chronic, intractable pain associated with pre-existing lumbar arachnoid fibrosis, after multiple myelograms and surgeries. ⋯ We have encountered a similar phenomenon, however, in a canine laboratory model. The pathological features in both our patient and our laboratory preparation, with inflammatory tissue masses around the tip of the catheter but not around proximal subarachnoid segments, suggest an effect related to infusion, as opposed to infection or the presence of the catheter. We review the pathological features in both settings and the pertinent literature.