Surgical management and alternative strategies for neighboring intracranial aneurysms

AIM

Neighboring aneurysms are misidentified or named as a single multi-lobulated aneurysm, despite the demonstration of angiographic cleavage, because of the close proximity and different size. During surgery, neighboring intracranial aneurysms represent an interesting subset of aneurysms that may pose unique management challenges. Meticulous preoperative radiological planning is necessary to properly appreciate the local anatomy. Intraoperative microsurgical dissection of these aneurysm complexes may be difficult if a plane cannot be created between the neighboring lesions with dissection of the aneurysm necks and preservation of blood flow becoming a challenging situation.

METHODS

A retrospective review over a 10-year period, of all patients with intracranial aneurysms treated by our service was performed to identify those patients with neighboring aneurysms.

RESULTS

We encountered 73 instances of neighboring aneurysms (MCA-22, PCOMMA/AChA-20, ACOMMA-15, paraclinoid-5, upper basilar-4, pericallosal-3, ICA bifurcation-2, VB junction-2). Most patients were managed with either microsurgery for both aneurysms or coiling for both. Seven patients with severe SAH underwent coiling of the presumed ruptured (much larger) aneurysm with subsequent microsurgery for the neighboring aneurysm which was not considered amenable to endovascular therapy. In the setting of neighboring lesions, microsurgery was sometimes deemed significantly more difficult than usual, particularly when the aneurysm domes were adherent precluding optimal visualization of the local vascular anatomy. Temporary vascular occlusion was often helpful to allow for proper inspection and identification of all perforating vessels initially hidden by the adherent sacs.

CONCLUSION

Neighboring intracranial aneurysms represent an interesting subset of aneurysms that may pose unique management challenges. Careful evaluation of preoperative angiography is necessary to properly appreciate the local anatomy in these cases. Microsurgical dissection of these aneurysm complexes may be difficult if a plane cannot be created between the neighboring lesions. Because neighboring aneurysms tend to obscure the local anatomy, intraoperative angiography and innovative surgical strategies were useful in our experience.

Non-infected carotid artery pseudoaneurysm 29 years after endarterectomy, endovascular management with covered stent

Pseudoaneurysm formation is a rare complication following carotid endarterectomy (CEA). Arterial pseudoaneurysms lack all three layers of the arterial wall that include the intima, media and adventitia. Pseudoaneurysms are most commonly seen after injuries to the artery in the form of blunt trauma and puncture, and are less common after surgeries such as carotid endarterectomy. These lesions present most frequently as enlarging, pulsatile, expandable masses associated with swelling and pain. Management of this complication is challenging. Traditionally, open surgical repair has been the preferred treatment. Recently, endovascular techniques using stent graft implantation alone or combined graft and coil embolization have offered a less invasive approach for the management of this lesion. Pseudoaneurysm development has been described within hours to several years after initial arterial injury, normally presenting within 5 years. To our knowledge, this is the first case report of pseudoaneurysm formation in a patient presenting 29 years after a carotid endarterectomy; during that time the patient remained completely asymptomatic until 2 months prior to his admission. The patient is an 84-year-old male with a history of stroke which prompted a left carotid endarterectomy in 1981. Twenty-nine years post procedure it was noted that the patient had a lump that was progressively enlarging on the left side of his neck, zone 1. It was pulsatile on examination. MRI/A imaging suggested a left carotid bulb aneurysm. The consulting vascular surgeon felt the patient would not be a good surgical candidate and so stenting was considered. Carotid and cerebral angiogram demonstrated a large 6 cm left carotid pseudoaneurysm off the carotid bulb. The diagnostic procedure was followed by a successful placement of an 8 x 10 cm Viabahn covered stent from the left common carotid artery to the left internal carotid artery. Following the procedure, the carotid artery was patent and there was minimal to no further residual filling of the pseudoaneurysm. Poststenting, the patient remained at his neurological baseline. This case demonstrates that pseudoaneurysm formation can occur as a long term complication after carotid endarterectomy. It may present as a rapidly expandable, pulsatile, vascular lesion in the absence of clinical and sub-clinical infection. Placement of an endovascular stent graft may be a safe and effective option for treatment of infected and non-infected carotid pseudoaneurysm.

Intracranial aneurysm formation in siblings with pseudoxanthoma elasticum: case report

Although intracranial aneurysms have been associated with many hereditary collagen disorders, the incidence of brain aneurysms in pseudoxanthoma elasticum (PXE) appears to be exceedingly low and uncertain. We describing a rare case of a sisters with PXE who both developed intracranial aneurysms. This report supports the previously questioned hypothetical association between PXE and intracranial aneurysms.

Pseudomyasthenia resulting from a posterior carotid artery wall aneurysm: a novel presentation: case report

OBJECTIVE AND IMPORTANCE

Painful oculomotor palsy can result from enlargement or rupture of intracranial aneurysms. The IIIrd cranial nerve dysfunction in this setting, whether partial or complete, is usually fixed or progressive and is sometimes reversible with surgery. We report an unusual oculomotor manifestation of a posterior carotid artery wall aneurysm, which mimicked ocular myasthenia gravis.

CLINICAL PRESENTATION

A 47-year-old woman developed painless, intermittent, partial IIIrd cranial nerve palsy. She presented with isolated episodic left-sided ptosis, which initially suggested a metabolic or neuromuscular disorder. However, digital subtraction angiography revealed a left posterior carotid artery wall aneurysm, just proximal to the origin of the posterior communicating artery.

INTERVENTION

The aneurysm was successfully clipped via a pterional craniotomy. During surgery, the aneurysm was observed to be compressing the oculomotor nerve. The patient's symptoms resolved after the operation.

CONCLUSION

The variability of incomplete IIIrd cranial nerve deficits can present a diagnostic challenge, and the approach for patients with isolated IIIrd cranial nerve palsies remains controversial. Although intracranial aneurysms compressing the oculomotor nerve classically produce fixed or progressive IIIrd cranial nerve palsies with pupillary involvement, anatomic variations may result in atypical presentations. With the exception of patients who present with pupil-sparing but otherwise complete IIIrd cranial nerve palsy, clinicians should always consider an intracranial aneurysm when confronted with even subtle dysfunction of the oculomotor nerve.

Delayed cerebrovascular complications of intrathecal colloidal gold

OBJECTIVE

Therapy with intrathecal colloidal gold has been used in the past as an adjunct in the treatment of childhood neoplasms, including medulloblastoma and leukemia. We describe the long-term follow-up period of a series of patients treated with intrathecal colloidal gold and emphasize the high incidence of delayed cerebrovascular complications and their management.

METHODS

Between 1967 and 1970, 14 children with posterior fossa medulloblastoma underwent treatment at the University of Minnesota. Treatment consisted of surgical resection, external beam radiotherapy, and intrathecal colloidal gold. All patients underwent long-term follow-up periods.

RESULTS

Of the 14 original patients, 6 died within 2 years of treatment; all experienced persistent or recurrent disease. The eight surviving patients developed significant neurovascular complications 5 to 20 years after treatment. Three patients died as a result of aneurysmal subarachnoid hemorrhage, and five developed ischemic symptoms from severe vasculopathy that resembled moyamoya disease.

CONCLUSION

Although therapy with colloidal gold resulted in long-term survival in a number of cases of childhood medulloblastoma, our experience suggests that the severe cerebrovascular side effects fail to justify its use. The unique complications associated with colloidal gold therapy, as well as the management of these complications, are presented. We recommend routine screening of any long-term survivors to exclude the presence of an intracranial aneurysm and to document the possibility of moyamoya syndrome.

Outcomes after aneurysm rupture during endovascular coil embolization

OBJECTIVE

Intracranial aneurysm rupture during placement of Guglielmi detachable coils has been reported, but the management and consequences of this event have not been extensively described. We present our experience with this feared complication and report possible neuroradiological and neurosurgical interventions to improve outcomes.

METHODS

We retrospectively reviewed the records for 701 patients with 734 intracranial aneurysms that were treated with endovascular coiling, during a 6-year period, in the metropolitan Minneapolis-St. Paul (Minnesota) area. This analysis revealed 10 cases of perforation during coiling. The management and outcomes were recorded, and the pertinent literature was reviewed.

RESULTS

All 10 cases involved previously ruptured aneurysms. This complication occurred sporadically and was not observed in the first 100 cases. Perforation occurred during microcatheterization of the aneurysm in two cases and during coil deposition in eight cases. Seven of the perforated aneurysms were located in the anterior circulation and three in the posterior circulation. Six of the 10 patients made good or fair recoveries; all three patients with posterior circulation lesions died immediately after rehemorrhage. Elevated intracranial pressure (ICP) was noted for all five patients with intraventricular catheters in place. Bilateral pupil dilation and profound hemodynamic changes were noted for eight patients. Coiling was rapidly completed, and total or nearly total occlusion was achieved in all cases. Emergency ventriculostomy was performed to rapidly reduce increased ICP for two patients, both of whom made good recoveries. Hemodynamic and angiographic factors after perforation, such as prolonged systemic hypertension, persistent dye extravasation after deployment of the first Guglielmi detachable coil, and persistent prolongation of contrast dye transit time (suggesting ongoing ICP elevation), were correlated with poor outcomes.

CONCLUSION

Previously ruptured aneurysms seem to be more susceptible to endovascular treatment-related perforation than are unruptured lesions. Worse prognoses are associated with iatrogenic rupture during coiling of posterior circulation lesions, compared with those in the anterior circulation. When perforation is recognized, the definitive treatment seems to be reversal of anticoagulation therapy and completion of Guglielmi detachable coil embolization. Immediate neurosurgical intervention is limited in these cases and focuses on decreasing ICP via emergency ventriculostomy. However, these measures may be life-saving, and neurosurgical assistance must be readily available during treatment of these cases.

Multiple intracranial aneurysms as delayed complications of an atrial myxoma: case report

OBJECTIVE AND IMPORTANCE

Atrial myxomas are rare cardiac tumors that may cause neurological complications; however, delayed neurological events after total tumor resection are rare. In this report, we present a patient who developed transient cerebral ischemic attacks and was found to have multiple intracranial aneurysms 5 years after successful resection of her atrial myxoma. At the time of myxoma resection, there were no neurological symptoms; at the time of presentation with transient ischemic attacks, there was no evidence of atrial recurrence.

CLINICAL PRESENTATION

A 32-year-old woman presented with five episodes of right arm and face paresthesia, each lasting 15 to 20 minutes, 5 years after successful resection of her atrial myxoma. Clopidogrel bisulfate therapy was initiated, with resolution of her symptoms. Angiography revealed multiple, peripherally located, fusiform cerebral aneurysms.

INTERVENTION

A left frontal craniotomy for resection and biopsy of one of the aneurysms was performed, to establish the diagnosis. Pathological analysis of the biopsied aneurysm provided evidence of direct atrial myxoma invasion and occlusion of the cerebral blood vessel.

CONCLUSION

Neurological symptoms may accompany or lead to the diagnosis of atrial myxoma. Rarely, as in this case, myxomatous aneurysms may develop years after definitive treatment of the primary tumor. Patients who have undergone successful resection of a left atrial myxoma may be at risk for delayed cerebral ischemia associated with aneurysm development, and this phenomenon must be considered for patients with neurological symptoms who present even years after myxoma removal. The natural history, pathophysiological features, and treatment dilemma of these aneurysms are discussed.

Ruptured intracranial aneurysms. A review of diagnosis and management

Despite decades of aggressive efforts to improve the outcome from ruptured intracranial aneurysms, subarachnoid hemorrhage (SAH) still carries high morbidity and mortality rates. Aneurysmal subarachnoid hemorrhage continues to be a frightening and poorly understood condition, contributing to delays in diagnosis and compromising patient care. Prompt diagnosis followed by aggressive treatment represents the best available method to improve patient outcome. Optimal results depend on rapid medical stabilization of the patient, early aneurysm repair to prevent rebleeding, and prevention of the recognized complications of subarachnoid hemorrhage. This review summarizes recommendations for managing the patient with a ruptured intracranial aneurysm.

Long-term survival with metastatic cancer to the brain

Metastatic cancer to the brain has a poor prognosis. The focus of this work was to determine the incidence of long-term (> or = 2y) survival for patients with brain metastases from different primary cancers and to identify prognostic variables associated with prolonged survival. A retrospective review of 740 patients with brain metastases treated over a 20 y period identified 51 that survived 2 or more years from the time of diagnosis of the brain metastasis. Prognostic variables that were examined included age, sex, histology, tumor number and location, and treatment. In the 51 patients, 35 (69%) had single lesions and 16 (31%) had multiple tumors. For all tumor types (740 patients), the actuarial survival rate was 8.1% at 2 y, 4.8% at 3 y, and 2.4% at 5 y. At 2 y, patients with ovarian carcinoma had the highest survival rate (23.9%) and patients with small cell lung cancer (SCLC) had the lowest survival rate (1.7%). At 5y, survival rates were 7.8% for ovarian carcinoma, 2.9% for non-SCLC, 2.3% for melanoma and renal cell carcinoma, 1.3% for breast carcinoma and there were no survivors with SCLC, gastrointestinal, bladder, unknown primary, or prostate cancer. Age, sex, histology, location for single tumors, systemic chemotherapy, and stereotactic radiosurgery did not significantly influence survival. The presence of a single lesion (P = 0.001, chi-square test), surgical resection (P= 0.001), and WBRT (P = 0.009) were favorable prognostic variables for extended survival. Multiple bilateral metastases was a poor prognostic indicator (P= 0.001). Multivariate analysis showed younger age (P< 0.05), single metastasis (P < 0.0001), surgical resection (P < 0.0001), whole brain radiation therapy (P < 0.0001), and chemotherapy (P = 0.0288) were associated with prolonged survival. 29 patients (57%) died of systemic disease progression, 9 (18%) died of central nervous system progression, and the cause of death was unknown in 3 (6%). Patients with a single non-SCLC, breast, melanoma, renal cell, and ovarian carcinoma brain metastasis have the best chance for long-term survival if treated with surgical resection and WBRT.

Carotid stenting and "extarterectomy" in the management of head and neck cancer involving the internal carotid artery: technical case report

OBJECTIVE AND IMPORTANCE

Head and neck cancer that invades the internal carotid artery (ICA) represents a significant management challenge. We describe a novel technique that allows for aggressive tumor removal without disrupting blood flow through the affected ICA.

CLINICAL PRESENTATION

A 62-year-old man was referred to our institution for management of a neck malignancy involving the ICA. Cerebral angiography suggested that there was good collateral flow from the opposite hemisphere, but the patient reported visual loss in the ipsilateral eye during balloon test occlusion of the ICA.

INTERVENTION

A self-expanding stent was deployed in the ICA; it spanned the entire length of the artery involved by tumor. One month later, the patient underwent tumor resection. During surgery, a long ICA arteriotomy was performed directly down to the mesh of the stent. A neoendothelium had formed within the stent, which prevented arterial bleeding. The carotid wall was dissected from the stent without difficulty and removed en bloc with the surrounding tumor. The exposed stent was wrapped circumferentially with a synthetic patch material. The patient tolerated the procedure well, and postoperative angiography demonstrated normal filling of the ICA.

CONCLUSION

We describe a novel approach to a patient with head and neck cancer involving the cervical ICA. Preliminary stenting, which allows time for endothelialization before surgery, may permit aggressive tumor resection without interrupting flow through the ICA. This technique obviates the need for complicated carotid reconstruction procedures and avoids the risk of delayed ischemia from carotid sacrifice.

Transient cardiac standstill induced by adenosine in the management of intraoperative aneurysmal rupture: technical case report

OBJECTIVE AND IMPORTANCE

Intraoperative aneurysmal rupture represents a potentially catastrophic event. We describe the use of an intravenous adenosine bolus to induce transient cardiac asystole to control a severe intraoperative aneurysmal rupture. This treatment resulted in a brief period of severe hypotension, which enabled successful clipping of the aneurysm.

CLINICAL PRESENTATION

A 55-year-old man was referred to our institution 7 days after experiencing a mild subarachnoid hemorrhage from a fusiform, multilobulated aneurysm of the anterior communicating artery. The patient was found to have multiple additional fusiform aneurysms as well as a large parietal arteriovenous malformation.

INTERVENTION

A craniotomy was performed to clip the aneurysm, but surgical dissection was complicated by premature rebleeding that could not be controlled satisfactorily with tamponade or temporary arterial occlusion. Infusion of adenosine resulted in the rapid onset of profound hypotension, allowing for safe completion of the dissection and clipping of the aneurysm with a good outcome. There were no complications identified in relation to the use of adenosine.

CONCLUSION

In the setting of severe intraoperative aneurysmal rupture, intravenous adenosine represents a potential means of achieving a near-immediate profound decrease in the blood pressure that may allow for safe completion of the dissection and aneurysm clipping.

Use of gadolinium as an intraarterial contrast agent in digital subtraction angiography of the cervical carotid arteries and intracranial circulation. Technical note

Patients with renal insufficiency or other contraindications to iodine-based contrast agents present a significant management dilemma when conventional arteriography is required. The authors describe the use of gadolinium as an alternative contrast agent for arterial digital subtraction (DS) angiography of the cervical carotid arteries (CAs) and intracranial circulation. Three patients with renal insufficiency presented with symptoms of ischemic cerebrovascular disease and inconclusive noninvasive imaging studies, which necessitated conventional angiography. Traditional transfemoral catheterization of the cervical CAs was performed and DS angiographic studies were obtained using gadolinium as an intraarterial contrast agent. In one case, selective arteriographic examination of the internal carotid arteries and vertebrobasilar system was performed as well. High-quality, diagnostic images essentially indistinguishable from routine angiographic studies were obtained in all cases. No patient suffered a complication related to the use of gadolinium, and no patient demonstrated worsened renal function after the procedure. In the setting of a contraindication to iodine-based contrast agents, gadolinium represents an important alternative contrast material that allows for excellent visualization of the cervical CAs and intracranial circulation.

Extracranial-intracranial bypass for ischemic cerebrovascular disease refractory to maximal medical therapy

OBJECTIVE

To examine the potential role of cerebral revascularization in the treatment of patients with symptomatic occlusive cerebrovascular disease refractory to medical therapy.

METHODS

Twenty patients with symptomatic occlusive cerebrovascular disease underwent 22 extracranial-intracranial bypass procedures after failing maximal medical therapy. The average follow-up time was 3.5 years, and no patient was lost to follow-up.

RESULTS

All patients presented with repeated transient ischemic attacks refractory to medical therapy. Angiographic findings included internal carotid artery occlusion in 8 patients, middle cerebral artery stenosis or occlusion in 4, moyamoya disease in 4, internal carotid artery dissection in 2, and supraclinoid internal carotid artery stenosis in 2. Outcome was excellent in 17 patients and good in 3. The only surgical complication occurred in one patient, who experienced postoperative seizures and required anticonvulsant therapy. There were no deaths in this series.

CONCLUSION

Although the Cooperative Study on Extracranial-Intracranial Bypass failed to show a benefit from the bypass procedure, we have continued to perform the operation in selected cases. Carefully selected individuals with occlusive cerebrovascular disease and persistent ischemic symptoms, despite maximal medical therapy, seem to obtain demonstrable and durable benefit from cerebral revascularization.

Diagnosis and management of carotid stenosis: a review

Since its introduction in the 1950s, carotid endarterectomy has become one of the most frequently performed operations in the United States. The tremendous appeal of a procedure that decreases the risk of stroke, coupled with the large number of individuals in the general population with carotid stenosis, has contributed to its popularity. To provide optimal patient care, the practicing physician must have a firm understanding of the proper evaluation and management of carotid stenosis. Nevertheless, because of the large number of clinical trials performed over the last decade addressing the treatment of stroke and carotid endarterectomy, the care of patients with carotid stenosis remains a frequently misunderstood topic. This review summarizes the current evaluation and treatment options for carotid stenosis and provides a rational management algorithm for this prevalent disease process.

The fate of intracranial microaneurysms treated with bipolar electrocoagulation and parent vessel reinforcement

OBJECTIVE

Although direct clipping remains the treatment of choice for intracranial aneurysms, not all aneurysms can be clipped. This report reviews the results of bipolar coagulation followed by parent vessel reinforcement for the treatment of intracranial microaneurysms (maximal diameter of < or =3 mm), with immediate and delayed postoperative angiographic evaluation in all cases.

METHODS

During a 1-year period, 20 intracranial microaneurysms in 12 patients were treated with bipolar electrocoagulation followed by reinforcement of the parent artery with muslin gauze. All patients underwent intraoperative or immediate postoperative angiographic evaluation, and all underwent follow-up angiographic evaluation approximately 1 year later. No patient was lost to follow-up monitoring.

RESULTS

Microaneurysms involved the middle cerebral artery (eight cases), internal carotid artery (six cases), anterior cerebral/anterior communicating artery (five cases), and superior cerebellar artery (one case). In all cases, the patient was undergoing a craniotomy for clipping of a larger aneurysm, and the microaneurysms were treated concurrently. At the time of the immediate angiographic examinations, 19 of 20 (95%) microaneurysms were no longer visible and 1 was substantially smaller (< 1-mm irregularity on the parent vessel). No patient experienced an adverse event related to microaneurysm treatment. In the 1-year follow-up examinations, there was no angiographic evidence of recurrence in the 19 cases with complete obliteration; the one residual aneurysm remained stable.

CONCLUSION

At 1 year, direct coagulation followed by parent vessel reinforcement seems to provide a satisfactory treatment option for intracranial microaneurysms.

Brain biopsy using high-field strength interventional magnetic resonance imaging

OBJECTIVE

Lesions within the brain are commonly sampled using stereotactic techniques. The advent of interventional magnetic resonance imaging (MRI) now allows neurosurgeons to interactively investigate specific regions, with exquisite observational detail. We evaluated the safety and efficacy of this new surgical approach.

METHODS

Between January 1997 and June 1998, 35 brain biopsies were performed in a high-field strength interventional MRI unit. All biopsies were performed using MRI-compatible instrumentation. Interactive scanning was used to confirm accurate positioning of the biopsy needle within the region of interest. Intraoperative pathological examination of the biopsy specimens was performed to verify the presence of diagnostic tissue, and intra- and postoperative imaging was performed to exclude the presence of intraoperative hemorrhage. Recently, magnetic resonance spectroscopic targeting was used for six patients.

RESULTS

Diagnostic tissue was obtained in all 35 brain biopsies and was used in therapeutic decision-making. Histological diagnoses included 28 primary brain tumors (12 glioblastomas multiforme, 9 oligodendrogliomas, 2 anaplastic astrocytomas, 2 astrocytomas, 1 lymphoma, and 1 anaplastic oligodendroglioma), 1 melanoma brain metastasis, 1 cavernous sinus meningioma, 1 cerebral infarction, 1 demyelinating process, and 3 cases of radiation necrosis. In all cases, magnetic resonance spectroscopy was accurate in distinguishing recurrent tumors (five cases) from radiation necrosis (one case). No patient sustained clinically or radiologically significant hemorrhage, as determined by intraoperative imaging performed immediately after the biopsy. One patient (3%) suffered transient hemiparesis after a pontine biopsy for investigation of a brain stem glioma. Another patient developed scalp cellulitis, with possible intracranial extension, 3 weeks after the biopsy; this condition was effectively treated with antibiotic therapy. Three patients were discharged on the day of the biopsy.

CONCLUSION

Interventional 1.5-T MRI is a safe and effective method for evaluating lesions of the brain. Magnetic resonance spectroscopic targeting is likely to augment the diagnostic yield of brain biopsies.

Reperfusion injury after focal cerebral ischemia: the role of inflammation and the therapeutic horizon

Recent evidence indicates that thrombolysis may be an effective therapy for the treatment of acute ischemic stroke. However, the reperfusion of ischemic brain comes with a price. In clinical trials, patients treated with thrombolytic therapy have shown a 6% rate of intracerebral hemorrhage, which was balanced against a 30% improvement in functional outcome over controls. Destruction of the microvasculature and extension of the infarct area occur after cerebral reperfusion. We have reviewed the existing data indicating that an inflammatory response occurring after the reestablishment of circulation has a causative role in this reperfusion injury. The recruitment of neutrophils to the area of ischemia, the first step to inflammation, involves the coordinated appearance of multiple proteins. Intercellular adhesion molecule-1 and integrins are adhesion molecules that are up-regulated in endothelial cells and leukocytes. Tumor necrosis factor-alpha, interleukin-1, and platelet-activating factor also participate in leukocyte accumulation and subsequent activation. Therapies that interfere with the functions of these factors have shown promise in reducing reperfusion injury and infarct extension in the experimental setting. They may prove to be useful adjuncts to thrombolytic therapy in the treatment of acute ischemic stroke.

High-field strength interventional magnetic resonance imaging for pediatric neurosurgery

BACKGROUND

Interventional magnetic resonance (MR) imaging allows neurosurgeons to interactively perform surgery using MR guidance. High-field (1.5-Tesla) strength imaging provides exceptional visualization of intracranial and spinal pathology. The full capabilities of this technology for pediatric neurosurgery have not been defined or determined.

MATERIALS AND METHODS

From January 1997 through June 1998, 10 of 85 cases performed in the interventional MR unit were in the pediatric population (mean age 8.3, median 8, range 2-15 years). Procedures included 2 brain biopsies, 5 craniotomies for tumor, 2 thoracic laminectomies for syringomyelia, and placement of a reservoir into a cystic brainstem tumor. The biopsies and reservoir placement were performed using MR-compatible equipment. Craniotomies and spinal surgery were performed with conventional instrumentation outside the 5-Gauss magnetic footprint. Interactive and intraoperative imaging was performed to assess the goals of surgery.

RESULTS

Both brain biopsies were diagnostic for cerebral infarct and anaplastic astrocytoma and the reservoir was optimally placed within the tumor cyst. Of the 5 tumor resections, all were considered radiographically complete. One biopsy patient and 1 tumor resection patient experienced transient neurological deficits after surgery. The patient with the thoracic syrinx required reoperation when the syringosubarachnoid shunt migrated into the syrinx 3 months after initial placement. No patient sustained a postoperative hemorrhage. Tumor histologies found at craniotomy were craniopharyngioma, ganglioglioma, and 3 low-grade gliomas. No evidence of tumor progression has been seen in any of these patients at a mean follow-up of 5.3 (range 4-8) months. The goals of the procedure were achieved in all 10 cases. There were no untoward events experienced related to MR-compatible instrumentation or intraoperative patient monitoring, despite the present inability to monitor core body temperature.

CONCLUSIONS

1.5-Tesla interventional MR is a safe and effective technology for assisting neurosurgeons to achieve the goals of pediatric neurosurgery. Preliminary results suggest that surgical resection of histologically benign tumors is enhanced in the interventional MR unit. The incidence of surgically related morbidity is low.

The pathogenesis of arteriovenous malformations: insights provided by a case of multiple arteriovenous malformations developing in relation to a developmental venous anomaly

OBJECTIVE AND IMPORTANCE

Developmental venous anomalies (DVAs) are common anomalies of intracranial venous drainage that may occur in conjunction with other cerebral vascular malformations. The present case raises important questions regarding the association between anomalous venous drainage patterns and the development of arteriovenous malformations (AVMs).

CLINICAL PRESENTATION

We present the case of a 24-year-old man with small AVMs fed by the superior cerebellar artery that drained directly into a large DVA of the cerebellum.

INTERVENTION

The patient was managed conservatively and returned 10 years later with recurrent symptoms. A repeat angiogram demonstrated spontaneous thrombosis of the previously documented AVMs; however, new AVMs at a different site that was also fed by the superior cerebellar artery and drained into the same DVA had appeared. The AVMs were completely embolized, and the DVA was left intact.

CONCLUSION

Recently, increasing attention has focused on the possible importance of venous outflow disturbance and venous hypertension in the pathogenesis and pathophysiology of AVMs. The potential mechanisms for this association and the implications of the present case are discussed, and the pertinent literature is reviewed.

Intra-aortic balloon counterpulsation augments cerebral blood flow in the patient with cerebral vasospasm: a xenon-enhanced computed tomography study

OBJECTIVE

We previously established the ability of intra-aortic balloon counterpulsation (IABC) to improve cerebral blood flow (CBF) significantly in a canine model of cerebral vasospasm. This study was performed to assess the efficacy of IABC in a patient with cardiac dysfunction and severe cerebral vasospasm that was refractory to traditional treatment measures.

METHODS

We report our experience with the clinical use of IABC to treat cerebral vasospasm in a patient who suffered subarachnoid hemorrhage and concomitant myocardial infarction. Hypertensive, hypervolemic, hemodilution therapy was ineffective, and IABC was instituted. Xenon-enhanced computed tomography (Xe-CT) was utilized to obtain serial measurements of CBF with and without IABC over a 4-day period.

RESULTS

IABC dramatically improved cardiac function in this patient, and Xe-CT demonstrated significant improvement in CBF with IABC. The average global CBF was 20.5 +/- 4.4 ml/100g/min before versus 34.7 +/- 3.8 ml/100g/min after IABC (p < 0.0001, paired student's t-test). The lower the CBF before IABC, the greater the improvement with IABC (correlation coefficient r = 0.83, p = 0.0007). CBF improvement ranged from 33% to 161% above baseline, average 69.3%. No complications of IABC were observed.

CONCLUSIONS

This is the first report demonstrating the ability of IABC to improve CBF in a patient with vasospasm. We suggest that IABC is a rational treatment option in select patients with refractory cerebral vasospasm who do not respond to traditional treatment measures.

Intracranial aneurysm rupture presenting as delayed stroke secondary to cerebral vasospasm

BACKGROUND

Days after aneurysmal subarachnoid hemorrhage (SAH), cerebral vasospasm can result in the delayed appearance of ischemic neurological deficit identical to that produced by other causes of stroke. Despite the well-described, "classic" presentation of SAH, up to 25% of patients are initially misdiagnosed, and the initial hemorrhage from a ruptured aneurysm will not always bring the patient to medical attention.

CASE DESCRIPTIONS

We report our experience with two patients who presented with signs and symptoms of ischemic stroke resulting from cerebral vasospasm that followed unrecognized rupture of a brain aneurysm. In one case, it was the recent complaint of significant headache and a prior history of SAH that led to the correct diagnosis. In the other case, a major rebleed occurred before the accurate diagnosis was recognized.

CONCLUSIONS

It is critical to make the correct diagnosis of stroke due to vasospasm so that appropriate treatment can be instituted, thrombolytic and anticoagulant therapy can be avoided, and the unsecured aneurysm can be obliterated to prevent potentially catastrophic rebleeding.

Brain metastases. Histology, multiplicity, surgery, and survival

BACKGROUND

With the advent of new therapies for metastatic carcinoma to the brain, patterns of intracranial disease and factors influencing survival become important considerations when examining potential treatment options.

METHODS

The records of 729 patients with metastases to the brain treated during the period between 1973 to 1993 were reviewed.

RESULTS

Primary tumor histologic type in order of descending frequency included nonsmall cell lung carcinoma (NSCLC), breast carcinoma, small cell lung carcinoma (SCLC), malignant melanoma, renal cell carcinoma, gastrointestinal carcinoma, uterine/vulvar carcinoma, and unknown primary carcinoma. There were 384 patients (53%) with a single brain metastasis, which was encountered most commonly in patients with prostate carcinoma and least often in patients with SCLC. Multiple metastases were present in 345 patients (47%). The median duration from diagnosis to presentation with a brain metastasis was 12 months, ranging from 3 months for patients with NSCLC to 53 months for patients with breast carcinoma. The median duration from presentation with brain metastases to death was 4 months, ranging from 3 months for patients with SCLC to 13 months for patients with prostate carcinoma. Median survival from presentation with brain metastases to death was 5 months for patients with single lesions and 3 months for patients with multifocal disease (P = 0.0001). Median survival for patients with a single lesion was 11 months with surgery and 3 months without surgery (P = 0.0001). Surgery did not significantly influence survival in patients with multiple metastases.

CONCLUSIONS

Dissemination of systemic carcinoma to the brain continues to carry a poor prognosis. Knowledge of the metastatic patterns and limited survival associated with specific tumor types may be useful for guiding future therapeutic intervention.

Cost-effectiveness of carotid endarterectomy

Carotid endarterectomy (CEA) reduces the risk of stroke in symptomatic patients with high-grade carotid stenosis. In this study, we evaluated the long-term, societal cost-benefit ratio of endarterectomy using a decision analysis model. We reviewed the results of 150 CEAs performed at an academic center and established a Markov model comparing cohorts of patients who experienced transient ischemic attacks and then underwent observation, aspirin therapy, or CEA. The cost-effectiveness of CEA was estimated using perioperative complication rates from our review and from the North American Symptomatic Carotid Endarterectomy Trial. Stroke and mortality rates were estimated from the literature. Cost estimates were based on medicare reimbursement data. Among the 150 CEAs reviewed, complications included major stroke (0.67%), minor stroke (1.33%), myocardial infarction (1.33%), pulmonary edema (0.67%), and wound hematoma (3.33%). There were no deaths or intracerebral hemorrhages. Using complication rates from our review, CEA produced cost savings of $5730.62 over the cost of observation and $3264.66 over the cost of aspirin treatment. CEA extended the average quality-adjusted life expectancy 15.8 months over that of observation and 13.2 months over that of aspirin. Substituting the North American Symptomatic Carotid Endarterectomy Trial results, CEA yielded savings of $2997.50 over the cost of observation and $531.54 over the cost of aspirin. Quality-adjusted life expectancy was extended 13.8 months compared with observation and 11.2 months compared with aspirin therapy. This analysis demonstrates that when performed with low perioperative morbidity and mortality rates, CEA is a highly cost-effective therapy for symptomatic carotid stenosis and results in substantial societal cost and life savings.

Spinal tuberculosis: a diagnostic and management challenge

The authors reviewed 29 cases of spinal tuberculosis treated from 1973 to 1993 with an average follow-up time of 7.4 years. Clinical findings included back pain, paraparesis, kyphosis, fever, sensory disturbance, and bowel and bladder dysfunction. Twenty-two patients (76%) presented with neurological deficit; 12 (41%) were initially misdiagnosed. Sixteen patients (55%) had predominant vertebral body involvement; nine had marked bone collapse with neurological compromise. Eleven individuals (39%) had intraspinal granulomatous tissue causing neurological dysfunction in the absence of bone destruction, and two (7%) had intramedullary tuberculomas. All patients received antituberculous medications: 13 were initially treated with bracing alone, eight underwent laminectomy and debridement of extra- or intradural granulomatous tissue, and eight underwent anterior, posterior, or combined fusion procedures. No patient with neurological deficit recovered or stabilized with nonoperative management. Thirteen patients were readmitted with progression of inadequately treated osteomyelitis; 12 (92%) of these required new or more radical fusion procedures. Anterior fusion failure was associated with marked preoperative kyphosis and multilevel disease requiring a graft that spanned more than two disc spaces. Courses of antibiotic medications shorter than 6 months were invariably associated with disease recurrence. It was concluded that 1) patients should receive at least 12 months of appropriate antituberculous therapy; 2) individuals with neurological deficit should undergo surgical decompression; 3) laminectomy and debridement are adequate for intraspinal granulomatous tissue in the absence of significant bone destruction; 4) when vertebral body involvement has produced wedging and kyphosis, aggressive debridement and fusion are indicated to prevent delayed instability and progression of disease.

Meningeal sarcoma mimicking an acute subdural hematoma on CT

A case of meningeal sarcoma arising at the site of a prior subdural hematoma and mimicking an acute subdural hematoma on noncontrast CT is presented. The potential confusion between a hyperdense, nonhemorrhagic lesion and a hematoma on CT is highlighted. This report also reviews the possible relationship between meningeal injury and subsequent neoplastic change.

Cyclosporine A toxicity presenting with acute cerebellar edema and brainstem compression. Case report

A 38-year-old man receiving cyclosporine A after bilateral lung transplantation for cystic fibrosis presented with cortical blindness, generalized seizures, and cerebellar edema. Progressive brainstem compression necessitated emergency posterior fossa decompression. Replacement of cyclosporine A with an alternative immunosuppressive agent, FK506, was followed by rapid neurological recovery and dramatic resolution of radiographic abnormalities. The etiology, clinical features, and radiographic findings of cyclosporine A neurotoxicity are discussed. The pertinent literature is reviewed.

Intra-aortic balloon counterpulsation augments cerebral blood flow in a canine model of subarachnoid hemorrhage-induced cerebral vasospasm

We tested the effect of intra-aortic balloon counterpulsation (IABC) on cerebral blood flow (CBF) in a canine model of cerebral vasospasm. Cerebral vasospasm was induced in ten adult mongrel dogs using a "two-hemorrhage" model. CBF was then measured using radiolabeled microspheres, before and after activation of an intra-aortic balloon pump. Physiologic parameters including pCO2 and cardiac filling pressures were maintained constant during the experiment. Cardiac output was monitored in each animal. CBF increased with IABC in all ten animals. The mean CBF was 78.5 milliliters per 100 grams per minute (ml/100g/min) before versus 93.3ml/100g/min after IABC (P = 0.0001). Increases in CBF were associated in most, but not all, cases with increases in cardiac output. This study supports the ability of IABC to raise CBF in the setting of cerebral vasospasm. IABC may represent an important clinical option in cases of refractory vasospasm following aneurysmal subarachnoid hemorrhage.

Epidural abscess in the cervical spine

A ten-year retrospective review of 23 cases of documented spinal epidural abscess in the cervical spine was undertaken to define the clinical features and establish current diagnostic and therapeutic criteria. Diagnosis was made by magnetic resonance imaging or myelography. Risk factors included intravenous drug abuse, diabetes mellitus, previous trauma, and a positive serologic test for the human immunodeficiency virus. A bacterial agent was isolated in 21 cases (91%). Neurologic deficits were present in 20 of the cases (87%) at the time of diagnosis. Erythrocyte sedimentation rate was elevated in all patients in whom it was measured. All patients were treated with appropriate antibiotics, usually for 6 to 8 weeks. Twenty-one patients underwent operative procedures using percutaneous aspiration (1 patient), the anterior approach (14 patients) or the posterior approach (4 patients), or a combination of the two approaches (2 patients). Four of ten patients who initially had less than antigravity strength were eventually ambulatory and continent; in each case, operative decompression was performed within 36 hours of initial consultation. Three patients who had no initial neurologic deficits remained intact.

Rhinocerebral mucormycosis: changing patterns of disease

Eleven cases of rhinocerebral mucormycosis (RM) encountered over a 13-year period were reviewed. Predisposing factors included leukemia (36%), diabetes mellitus (27%), aplastic anemia (9%), myelodysplastic syndrome (9%), and treatment with immunosuppressive medications necessary to maintain solid organ or bone marrow graft viability (64%). Two patients had no predisposing factors. Clinical findings included headache (73%), fever (55%), black nasal eschar (45%), orbitofacial cellulitis (36%), cranial nerve palsy (36%), altered sensorium (36%), and hemiparesis (27%). Seven patients presented with destruction of the paranasal sinuses and local invasion; three with direct extension to the frontal or temporal lobes. Four patients displayed hematogenous dissemination to the cerebrum, brain stem, and cerebellum from a primary pulmonary focus. The seven patients with sinus involvement were treated with aggressive surgical debridement. Two patients with focal intracerebral lesions underwent either open craniotomy or stereotactic biopsy. Amphotericin B was administered intravenously to all patients. Local irrigation via a percutaneous catheter was performed in the seven patients with sinus disease and in one case of intracranial abscess. All seven patients with intracranial infection died, in contrast to four patients that survived with infection localized to the sinuses and orbits. All survivors had been treated with a combination of surgery and amphotericin B therapy. This review demonstrates that RM is increasingly affecting patients with sources of immunosuppression other than diabetes mellitus. Early aggressive therapy to prevent cerebral involvement by this severe infection provides the best chance for a good outcome.

Spinal epidural abscess: A report of 40 cases and review

Despite modern medical advances, the morbidity and mortality rates associated with spinal epidural abscess remain significant, and the diagnosis often is elusive. A retrospective study was undertaken to define better the incidence and clinical features of this infection, and to establish current diagnostic and therapeutic guidelines. Forty cases of spinal epidural abscess were encountered at our institution between July 1979 and March 1991. All medical records and radiological images were reviewed. We report a significant increase in the incidence of epidural abscess after June 1988 (p = 0.0195). Sixteen patients used drugs intravenously, and six had undergone spinal procedures. Twelve patients were misdiagnosed in various emergency rooms or clinics and discharged. Localized back pain, fever, and neurological deficit remained the typical clinical manifestations. Erythrocyte sedimentation rate was elevated uniformly when measured (21 cases). Magnetic resonance imaging was diagnostic specifically in 23 of 24 instances. The majority of patients underwent surgical drainage, but five selected patients were managed nonoperatively. The highly variable presentation of spinal epidural abscess may confuse the diagnosis and delay indicated surgical intervention. Localized back pain in a febrile patient at significant risk for epidural abscess warrants erythrocyte sedimentation rate measurement. The presence of erythrocyte sedimentation rate elevation or evidence of spinal cord compression on physical examination are indications for immediate magnetic resonance imaging examination with contrast enhancement. Surgical drainage with sustained intravenous antibiotic treatment remains the cornerstone of therapy. Nonoperative management may be considered in selected cases.

Myelographic and enhanced computed tomographic appearance of acute traumatic spinal cord avulsion

The neuroradiological findings that revealed spinal cord transection/laceration in 6 patients with acute, blunt spinal trauma are described. Four patients suffered cervical spine injuries, and two had thoracic injuries. Initially, all patients had complete neurological deficit at the level of injury. The deficit improved in only 1 patient. On the basis of clinical history and spinal radiographs, spinal hyperflexion with distraction was the predominant mechanism of injury in our patients. Computed tomography with intrathecal contrast was performed on all patients and was always diagnostic. Visualization of intrathecal contrast material accumulating within the cord or the absence of cord shadow within the contrast column established the diagnosis in all cases. A dural tear was noted in 3 patients. Thoracic myelography was performed in 2 patients and, in both, demonstrated contrast pooling within the spinal cord at the level of the laceration. Magnetic resonance imaging was obtained in 1 patient and revealed an irregular, low-signal-intensity, intramedullary region extending to the cord surface on T1-weighted axial images. The myelographic and enhanced computed tomographic appearances of acute, traumatic spinal cord avulsion/laceration, which have been infrequently reported in the literature, are described.

Complete temporal lobectomy for surgical resuscitation of patients with transtentorial herniation secondary to unilateral hemispheric swelling

Transtentorial herniation is an ominous finding in the patient with head injuries. We report our experience with 10 patients suffering from acute transtentorial herniation secondary to posttraumatic unilateral hemispheric swelling who were treated aggressively with temporal lobectomy. Eight patients were men and 2 were women. Their ages ranged from 22 to 61 years, with a mean of 37 years. Their preoperative Glasgow Coma Scale scores ranged from 3 to 6, with a mean of 4. All patients had both computed tomographic and clinical evidence of unilateral hemispheric shift and acute herniation without a significant subdural or epidural hematoma. Seven patients had unilateral nonreactive pupils and 3 had bilateral nonreactive pupils. All were taken to the operating room within 2 hours of clinical signs of herniation. Complete unilateral temporal lobectomies including the mesial structures, amygdala, and uncus were performed. In this series, the mortality rate was 30%, including a single patient who was neurologically stable but died from nonneurological injuries. Of the 7 survivors, 4 were functionally independent and 3 required minimal assistance with the activities of daily living. Aggressive, early decompression via complete temporal lobectomy may thus significantly improve the outcome in patients with transtentorial herniation accompanying posttraumatic hemispheric swelling and midline shift.