Anesthetic management of labor and delivery in patients with elevated intracranial pressure.

The anesthetic management of labor and delivery in patients with elevated intracranial pressure is complex. This review discusses the etiologies of diffuse and focal pathologies which lead to elevated intracranial pressure in pregnancy. The role of neuraxial and general anesthesia in the management of labor and delivery is also examined. Finally, a comprehensive review of strategies to minimize increases in intracranial pressure during general anesthesia for cesarean delivery is presented.

Endarterectomy of the intradural vertebral artery via the far lateral approach.

Transient ischemic attacks (TIAs) of the posterior circulation are associated with a significant risk of subsequent infarction, particularly when caused by stenotic lesions in the intracranial portion of the vertebral artery (VA). Eight patients who had persistent posterior circulation TIAs despite receiving maximal medical therapy (including anticoagulation) and who had angiographic evidence of severe stenosis of the proximal intracranial VA with poor collateral flow were treated by endarterectomy of the intradural VA. Their ages ranged from 52 to 65 years. Five of these operations were performed via the far lateral approach. In all patients, the contralateral VA was hypoplastic or occluded, or ended in the posterior inferior cerebellar artery. Postoperative angiograms showed that the arteries of five of the patients were widely patent, one was improved but still stenotic, and two were occluded. The latter two patients subsequently underwent thrombectomy, after which the artery was patent in one patient and remained occluded in the other. After surgery, the TIAs of seven patients were relieved completely, and the patients were neurologically intact. The patient with persistent occlusion ultimately had moderate disability. Complications included the two cases of thrombotic occlusion that required a second operation, three cases of communicating hydrocephalus that required lumboperitoneal shunts, and two cases of transient dysfunction of the 9th and 10th cranial nerves. Suitable patients with persistent posterior circulation TIAs refractory to medical therapy who have appropriate angiographic evidence of proximal VA stenosis and poor collateral flow may benefit from endarterectomy of the intradural VA.(ABSTRACT TRUNCATED AT 250 WORDS)

Bovine pericardium for dural grafts: clinical results in 35 patients.

OBJECTIVE: The United States Food and Drug Administration has recently approved the marketing of bovine pericardium as a dural graft material, but literature reports of this use are limited. Bovine pericardium has been widely used for grafts in cardiac surgery and seems to have suitable properties for use as a dural graft. We report the use of glutaraldehyde-processed bovine pericardium for dural grafts in 35 patients undergoing cranial and craniospinal operations with the objective of providing a clinical assessment of this material and technique. METHODS: This report is a retrospective analysis of 35 patients. All available records were reviewed and information regarding the indication for grafting, graft size, complications, and outcome were collected and analyzed for all patients. RESULTS: Indications for grafting included meningioma resection, posterior fossa craniotomy, Chiari decompression, dural-based metastases, and trauma. Outcomes were good or excellent in 32 patients; the three fair or poor outcomes were not related to surgical closure. In no patient was the dural graft a significant factor in outcome. Bovine pericardium was found to be easily sutured to be watertight using standard suture material. The material is relatively inexpensive and requires no additional incision. It has low antigenicity and toxicity, good strength, and minimal elasticity. CONCLUSION: In this clinical assessment, bovine pericardium was found to be an excellent dural graft material.

Rupture of a giant carotid aneurysm after extracranial-to-intracranial bypass surgery.

We report a case of a fatal rupture of a previously unruptured giant aneurysm of the bifurcation of the internal carotid artery (ICA), which occurred after an extracranial-intracranial (EC-IC) bypass and the partial occlusion of the ICA. Interim angiography showed retrograde filling of the proximal middle cerebral artery to the aneurysm. There have been four previously reported cases of giant aneurysms rupturing after treatment with an EC-IC bypass and carotid ligation, and it appears likely that a change in pressure/flow dynamics produced by the bypass may have been the cause. The technique of carotid ligation with an EC-IC bypass is used frequently to treat unclippable intracranial aneurysms, and the resulting hemodynamic changes need to be considered carefully to prevent this type of complication. To minimize hemodynamic stress on the aneurysm, we suggest that 1) the bypass caliber should be as small as possible consistent with sufficient cerebral blood flow after ICA occlusion, and 2) complete ICA occlusion should be performed as soon as possible after the bypass.

Resection of giant invasive pituitary tumors through a transfacial approach: technical case report.

Giant invasive pituitary adenomas are rare tumors that have been reported to extensively involve the cranial base, as well as other intra- and extra-cranial structures, making surgical resection by traditional approaches impossible. We report two cases, each of a giant invasive adenoma involving the entire length of the clivus and adjacent structures that was resected via a transfacial approach with excellent results. Both tumors were in middle-aged men; one was nonsecreting, and the other secreted follicle-stimulating hormone alpha-subunit. Most previously reported giant invasive adenomas have been prolactinomas. Both tumors were resected via a transfacial approach that incorporated an osteoplastic maxillotomy with palatal division and a posterior pharyngeal incision that provided exposure from the suprasellar region to C2. Both of the patients received postoperative radiation and have done very well. Their cosmetic results were excellent. The complications included postoperative meningitis in one patient and a nasal voice in the other. The transfacial approach provides excellent access for this type of extensive midline tumor requiring resection from the suprasellar region down to the foramen magnum.

Surgical decisions on the basis of magnetic resonance angiography of the carotid arteries.

The recent demonstration of the efficacy of carotid endarterectomy in certain patients emphasizes the advantages of having a noninvasive, accurate means of evaluating the carotid arteries. Advances in magnetic resonance (MR) angiography now allow accurate depiction of the carotid arteries that may be adequate for surgical planning in many cases. This report examines the accuracy of MR angiography compared with that of conventional angiography in symptomatic patients undergoing carotid endarterectomy and compares them with surgical findings. Twenty-one carotid arteries in 20 patients were treated surgically for severe stenosis or occlusion. Preoperatively, all patients had both MR and conventional angiograms, which were interpreted on a five-grade scale by two independent neuroradiologists who were unaware of the patient's clinical history. The two studies were highly correlated, particularly in the case of severe stenosis and occlusion. There were no false-negative MR studies that missed surgically significant lesions. In two cases, MR angiography overestimated the stenosis by one grade. On MR angiography, surgically significant stenosis appears as focal areas of signal intensity loss at the level of stenosis with reappearance of the signal distally. If the distal signal intensity does not reappear, the artery is likely to be occluded. In symptomatic patients, MR angiograms that demonstrate a flow-void gap with distal reappearance at a site consistent with the symptoms may be adequate as the sole preoperative study. Three patients who underwent carotid endarterectomy on this basis are presented. The factors that contribute to artifactual and overestimated stenosis are reviewed.

Surgical resection of intramedullary spinal cord cavernous malformations: delayed complications, long-term outcomes, and association with cryptic venous malformations.

OBJECTIVE: To examine outcomes and delayed complications after the surgical resection of intramedullary spinal cord (IMSC) cavernous malformations. The association of these lesions with cryptic intraparenchymal venous malformations at surgery also was analyzed. METHODS: The records of 17 patients who underwent resection of their histologically verified IMSC cavernous malformations were analyzed. There were nine female and eight male patients (mean age, 40.1 yr). The locations of the cavernous malformations were as follows: cervical, eight; thoracic, eight; and conus medullaris, one. The mean follow-up period was 48.3 months. Immediate postoperative and long-term neurological outcomes were compared, and delayed complications were assessed. RESULTS: The patients presented with radiculopathy (n = 6), myelopathy (n = 10), and conus medullaris syndrome (n = 1). Intraoperatively, 16 (94.1%) IMSC cavernous malformations were associated with cryptic venous malformations. Immediately after surgery, four (23.5%) patients worsened neurologically whereas one (5.9%) improved. At long-term follow-up, however, 10 (58.9%) patients had improved and only 1 (5.9%) remained worse. Four (23.5%) patients experienced delayed complications. Three had undergone incomplete resection and experienced subsequent hemorrhage, necessitating subsequent resection. Another patient developed radiological tethering of the thoracic spinal cord without clinical symptoms. Two of the three patients who had undergone subsequent resection developed symptomatic tethering of the cervical spinal cord. In one of the two patients, the tethering was associated with an iatrogenic cerebellar tonsillar herniation. Both patients required surgical intervention. CONCLUSIONS: The frequent coexistence of IMSC cavernous malformations with cryptic venous malformations in this series indicates a need for operative vigilance to preserve these venous anomalies. Delayed complications were the result of incomplete resection. The resultant hemorrhage required reexploration, which led to tethering of the spinal cord. Most patients who underwent resection, however, had improved neurologically at long-term follow-up.

A comparison of fluoroscopy and computed tomography-derived volumetric multiple exposure transmission holography for the guidance of lumbar pedicle screw insertion.

Holographic technology has recently been modified in such a manner that it may now provide clinical use. It allows the visualization of complex structures in three dimensions and permits clinician interaction with the image, which, in turn, provides significant additional geometric and anatomic information. To objectively assess the potential clinical applicability of holography in pedicle screw placement, we studied 11 elderly human cadavers. All of the cadavers, each of which showed significant degenerative disease of the lumbar spine, underwent thin-section computed tomographic scans of the lumbar spine. The acquired digital information was processed, and volumetric multiple exposure transmission holographic images were rendered. Pedicle screws were passed into anatomically acceptable and radiographically visualized L3-L5 pedicles in each cadaver, half using fluoroscopic guidance and half using holographic guidance alone. The accuracy of screw placement was objectively assessed by a three-point grading scale. The total score for the placement of each pedicle screw was determined by both trajectory (location within the pedicle) and accuracy (containment within the vertebral body) of screw tip placement parameters. Three points were possible for each screw placed. Screw placement in the last six cadavers was individually timed for each technique, and fluoroscopic time was also recorded. Each technique was used on 27 pedicles. The total score for fluoroscopic screw placement was 71 (71 of a possible 81; 88%) and for holographic screw placement was 74 (74 of a possible 81; 91%). In the last six cadavers, the screw placement time (per cadaver) was 8 minutes for fluoroscopic placement and 3.6 minutes for holographic placement. Fluoroscopic time averaged 1.9 minutes per cadaver.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical resection of intramedullary spinal cord cavernous malformations.

Cavernous malformations are being increasingly well recognized throughout the central nervous system, where they compose approximately 1% of all vascular lesions and 15% of all vascular malformations. These malformations are uncommon in the spinal column and rarely found within the spinal cord. There have been only a few isolated reports of surgical resection of intramedullary spinal cord cavernous malformations. A series of six patients with intramedullary spinal cord cavernous malformations is described; all were treated by complete surgical excision, and all had a good or excellent outcome with partial or complete relief of neurological symptoms. There were no surgical complications, although transient postoperative neurological worsening was common. The clinical, radiological, and surgical features of these patients are discussed. It is concluded that intramedullary spinal cord cavernous malformations are an uncommon cause of progressive myelopathy that can be safely and effectively treated by surgical excision.

Giant serpentine middle cerebral artery aneurysm treated by extracranial-intracranial bypass. Case report.

Giant intracranial aneurysms often pose difficult management issues. Such aneurysms may not be amenable to direct surgical attack because of their size, location, or lack of a clear aneurysmal neck. In such cases, a combination of strategies may provide a means of proximal aneurysm occlusion and distal cerebral revascularization. The authors report the successful treatment of a giant (186.8-ml) serpentine aneurysm of the left middle cerebral artery (MCA) in a 14-year-old boy. The aneurysm was managed in a two-stage procedure in which the MCA branches distal to the aneurysm were anastomosed first with branches of the left superficial temporal artery. After the bypass procedure, direct occlusion of the MCA was performed at the proximal base of the aneurysm at its site of dilatation. The patient had no intraoperative or postoperative complications and was intact neurologically 6 months following the procedures.

Subarachnoid hemorrhage in sickle-cell disease.

The neurological complications of sickle-cell disease include cerebral intracerebral hemorrhage; subarachnoid hemorrhage (SAH) has been infrequently reported. Among 325 patients with sickle-cell disease followed at the University of Illinois between 1975 and 1989, 11 cases of SAH were identified. Aneurysms were found in 10 of these patients, three of whom had multiple aneurysms. All of the patients had some degree of anemia and nine underwent craniotomy without hematological or neurological complications. From this review it appears that SAH is not uncommon in sickle-cell disease patients and tends to occur at a younger age and with smaller aneurysm size than in the general population. With proper perioperative management, including exchange transfusions to reduce the proportion of hemoglobin S to less than 30%, these patients can undergo angiography and craniotomy without an increased incidence of complications. The techniques used in managing sickle-cell disease patients with SAH are discussed.

Spinal aneurysm of the lateral sacral artery. Case report.

Spinal aneurysms are rare, and those not associated with either an arteriovenous malformation or coarctation of the aorta are particularly rare. In this report, the authors present a case of spinal aneurysm involving the lateral sacral artery. The aneurysm presented as a cauda equina syndrome 6 years after the patient underwent a renal transplant contralateral to the side of the aneurysm parent vessel. To the authors' knowledge, only one similar case has been previously reported. They conclude that spinal aneurysms should be included in the differential diagnosis of an extramedullary spinal mass lesion.

Characteristics and surgical treatment of dolichoectatic and fusiform aneurysms.

Dolichoectatic and fusiform aneurysms represent a small subset of cerebral aneurysms and are often among the most difficult to treat. A consecutive series of 40 patients with 41 of these two types of aneurysms is presented, including their clinical characteristics and surgical treatments. Common to all aneurysms was the pathological involvement of a length of blood vessel with separate inflow and outflow sites (nonsaccular). However, dolichoectatic aneurysms have markedly different symptoms and surgical treatments depending on their location in either the anterior or posterior circulation. Anterior circulation aneurysms involved the petrous internal carotid artery (ICA) in one, the supraclinoid ICA in three, the middle cerebral artery in 13, and the anterior cerebral artery in four patients. Posterior circulation aneurysms involved the basilar artery in 13, the vertebral artery in six, and the posterior inferior cerebellar artery in one patient. Various surgical procedures were performed, including direct clipping, trapping with bypass, proximal occlusion, resection with reanastomosis, transposition, aneurysmorrhaphy with thrombectomy, and wrapping. There was no surgical mortality in the patient series, and treatment was effective in many patients. Overall, outcome at late follow up was good (Glasgow Outcome Scale scores 1-2) in 78% of patients. Patients with anterior circulation aneurysms had better outcomes than patients with posterior circulation aneurysms, with good outcomes in 90% and 65% of the cases, respectively. Dolichoectatic and giant serpentine aneurysms may develop from smaller fusiform aneurysms and represent a spectrum of the same pathological entity. Arterial dissection may also play a role in the initial development of these aneurysms.

Treatment strategies for intracranial fusiform aneurysms.

Fusiform aneurysms represent a small subset of intracranial aneurysms that form from the pathological circumferential dilatation of a length of cerebral artery. These lesions have separate inflow and outflow sites and frequently differ from saccular aneurysms in both their clinical presentations and surgical treatment. Thromboembolic complications and hemorrhage occur from these aneurysms. This article reviews the pathophysiology and clinical presentation of fusiform aneurysms and also discusses some of the special considerations regarding surgical treatment of these lesions.

Diagnostic accuracy of AIDS-related CNS lesions.

Because of the high incidence of neurological complications seen in patients with acquired immunodeficiency syndrome (AIDS), an increasing number of these cases are being referred to neurosurgeons for consideration of intracranial biopsy. To better determine the need for biopsy in these patients we evaluated the accuracy of non-tissue-based neurological diagnoses in AIDS patients who subsequently had a final diagnosis on the basis of biopsy or postmortem brain examinations. The records of 56 AIDS patients who had undergone either autopsy or brain biopsy were retrospectively reviewed. Of the ten patients who underwent biopsy, three were found to have a lesion that was different from the suspected diagnosis and that resulted in a change in treatment. Thirty patients with neurological symptoms had postmortem brain examinations. In the case of the 12 patients who had carried specific diagnoses and received treatments based on those diagnoses, only six diagnoses (50%) were proven correct at autopsy. Of the 18 cases that did not record a specific antemortem diagnosis, in only 5 were normal brains reported, while the others reported a variety of nonspecific or infectious findings. Twelve patients without neurological symptoms had postmortem brain examinations and only six of these (50%) had normal or slightly atrophic brains. Case reports of the others noted nonspecific findings most of which were suggestive of subacute HIV encephalitis. The poor rate of diagnostic accuracy in this series suggests that biopsy should be considered for atypical lesions or those that do not respond to empiric therapy. The use and relative sensitivities of various diagnostic studies are also discussed.

Spinal extradural angiolipoma: a report of two cases and review of the literature.

Extradural angiolipomas are rare tumors that can produce spinal cord compression. Two patients with thoracic spinal angiolipoma are presented that were treated with surgical resection and radiation. The histological and clinical features of the 18 previously reported cases of these tumors are discussed.

Use of gadolinium-enhanced magnetic resonance imaging in the diagnosis and management of posterior fossa hemangioblastomas.

The diagnosis of central nervous system hemangioblastoma as well as the surgical treatment requires the accurate radiologic visualization of both the cystic and solid components of the tumor. We report two cases of posterior fossa hemangioblastoma examined with gadolinium-diethylenetriaminepentaacetic acid-enhanced magnetic resonance imaging, which clearly defined the tumor nodule that was not visualized on noncontrast magnetic resonance imaging, contrast-enhanced computed tomography scans, or angiography. In both cases the operative findings precisely correlated with the gadolinium-enhanced magnetic resonance image. Gadolinium-enhanced magnetic resonance imaging is the examination of choice for preoperative evaluation of posterior fossa hemangioblastoma. In cases of von Hippel-Lindau syndrome, magnetic resonance imaging is a useful tool for clinical screening as well as follow-up.

Post-ictal Klüver-Bucy syndrome after temporal lobectomy.

In both animals and humans, Klüver-Bucy syndrome is produced by bilateral temporal lobectomy. It is characterised by hypersexuality, visual agnosia, strong oral tendencies, dietary changes, and hypermetamorphosis. Recurrent, postictal Klüver-Bucy syndrome occurred transiently after seizures in a female who had undergone unilateral temporal lobectomy. The pathophysiological mechanism may have been postictal dysfunction of the remaining temporal lobe, producing a transient functional bilateral temporal lobectomy.

Carotid endarterectomy.

The Council on Scientific Affairs of the California Medical Association presents the following inventory of items of progress in neurosurgery. Each item, in the judgement of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and important clinical significance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, researchers, and scholars to stay abreast of these items of progress in neurosurgery that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another. The items of progress listed below were selected by the Advisory Panel to the Section on Neurosurgery of the California Medical Association, and the summaries were prepared under its direction.