Radiosurgical management of benign cavernous sinus tumors: dose profiles and acute complications.

OBJECTIVE: Radiosurgery has emerged as an alternative treatment modality for cranial base tumors in patients deemed not suited for primary surgical extirpation, patients with recurrent or residual tumor after open surgery, or patients who refuse surgical treatment. We review our short-term experience with radiosurgical management of cavernous sinus region tumors with the Leksell gamma knife. METHODS: From August 1994 to February 1999, 69 patients with cavernous sinus lesions were treated in 72 separate treatment sessions. The tumor type distribution was 29 pituitary adenomas, 35 meningiomas, 4 schwannomas, and 1 paraganglioma. The median follow-up was 122 weeks. Lesions were stratified according to a five-level surgical grade. The grade distribution of the tumors was as follows: Grade I, 13; Grade II, 21; Grade III, 19; Grade IV, 12; Grade V, 4. Median tumor volume was 4.7 cm3. The median radiation dose was 15 Gy to the 50% isodose line. Median maximal radiation dose was 30 Gy. RESULTS: Analysis of tumor characteristics and radiation dose to optic nerve and pontine structures revealed a significant correlation between distance and dose. Much lower correlation coefficients were found between tumor volume and dose. One lesion in this series had evidence of transient progression and later regression on follow-up radiographic studies. No other lesions in this series were demonstrated to have exhibited progression. Complications after radiosurgical treatment were uncommon. Two patients had cranial nerve deficits after treatment. One patient with a surgical Grade III pituitary adenoma had VIth cranial nerve palsy 25 months after radiosurgical treatment that spontaneously resolved 10 months later. A patient with a bilateral pituitary adenoma experienced bilateral VIth cranial nerve palsy 3 months after treatment that had not resolved at 35 months after treatment. Six patients with preoperative cranial nerve deficits experienced resolution or improvement of their deficits after treatment. One patient with a prolactin-secreting adenoma experienced normalization of endocrine function with return of menses. CONCLUSION: Radiosurgical treatment represents an important advance in the management of cavernous sinus tumors, with low risk of neurological deficit in comparison with open surgical treatment, even in patients with high surgical grades.

Treating stroke as a medical emergency: a survey of resident physicians' attitudes toward "brain attack" and carotid endarterectomy.

OBJECTIVE: A major impetus of the "brain attack" campaign is the early recognition and treatment of acute stroke. Critical to this goal is the education of physicians during their residency training. METHODS: Resident physicians in Los Angeles who were in family practice (18%), internal medicine (51%), emergency medicine (20%), and neurology (11%) and had already completed their first year of training responded to a questionnaire on stroke and the treatment of carotid stenosis. RESULTS: Of the 266 respondents, 76% had heard of the "brain attack" campaign, 22% did not identify dysarthria as a symptom of stroke, and 21% did not identify obtundation as a presentation of stroke. Twenty-eight percent chose not to use tissue plasminogen activator for acute ischemic stroke, and 60% recognized the need to begin treatment within 3 hours. More than 90% of respondents were able to identify correct screening tests for patients with suspected carotid stenosis. However, 56% responded that they would not advocate operating on patients with asymptomatic severe stenosis (>70%) until stenosis reached a critical value (85%). Conversely, 45% would recommend operative treatment for symptomatic patients who had less than 60% stenosis. Sixty-eight percent would refer patients to vascular surgeons, 14% to neurosurgeons, and 17% to both for carotid endarterectomy. CONCLUSION: Recognition of stroke as a medical emergency is improving. However, significant progress can still be made in the recognition of stroke symptoms. Primary care and neurology residents remain skeptical about carotid endarterectomy for asymptomatic patients, whereas there is enthusiasm for treating stroke survivors. Education by members of the surgical community could promote the aggressive treatment of asymptomatic patients to prevent stroke.

Mismatch between BDNF mRNA and protein expression in the developing visual cortex: the role of visual experience.

Brain-derived neurotrophic factor (BDNF) messenger RNA (mRNA) expression in the rat visual cortex of young and postnatal day 90 (P90) animals is developmentally regulated and influenced by visual experience. In the present paper we compared the expression of BDNF mRNA to the actual changes of BDNF protein occurring during postnatal development and verified whether BDNF protein distribution is controlled by visual activity. To achieve this aim we analysed BDNF mRNA and/or BDNF protein cellular distribution in the rat visual cortex at different postnatal ages by using immunohistochemistry and highly sensitive in situ hybridization. We found that before eye opening (P13), in all cortical layers a large number of visual cortical neurons contain BDNF mRNA with no detectable amount of BDNF protein. At later ages (P23 and P90), the number of BDNF-immunostained cells increases; most neurons are double labelled for BDNF mRNA and protein, and a small group of neurons is labelled only for BDNF protein. The cellular increase of BDNF immunolabelling is blocked in animals deprived of visual experience from birth (dark rearing), with a large population of neurons containing BDNF mRNA but not BDNF protein. This is similar to what is observed before eye opening. Exposure of dark-reared rats to a brief period (2 h) of light restores a good match between BDNF mRNA and BDNF protein cellular expression. We propose that visual experience controls the neuronal content of BDNF mRNA and BDNF protein in developing visual cortex.

Stereotactic radiosurgery in the treatment of metastatic disease to the brain.

OBJECTIVE: In recent years, stereotactic radiosurgery has been growing in popularity as a treatment modality for metastatic disease to the brain. The technique has advantages of reduced cost and low morbidity compared with open surgical treatment. Furthermore, it avoids the potential cognitive side effects of fractionated whole-brain radiotherapy. We undertook this study to determine the usefulness of adjuvant radiation therapy and to determine prognostic factors in patients treated with stereotactic radiosurgery. METHODS: We reviewed our series of patients with metastatic tumors treated using gamma knife stereotactic radiosurgery from August 1994 to February 1999. Nonparametric methods were used to compare treatment subgroups by demographic features including age, Karnofsky Performance Scale score, diagnosis, and systemic disease status. Univariate and multivariate analyses of survival and freedom from progression were performed using Kaplan-Meier and Cox proportional hazards regression techniques. RESULTS: This study included 190 patients harboring 431 lesions who were treated in 263 treatment sessions. The median follow-up after radiosurgery was 36 weeks for all patients. The median actuarial survival from the time of radiosurgery in all patients was 34 weeks. When patients were stratified according to tumor histology, those without melanoma had a median survival of 39 weeks, and those with melanoma had a median survival of 28 weeks. The cause of death could be determined in 122 (92%) of the patients known to have died during the data capture period. For patients harboring melanoma, death was attributable to systemic disease in 31 (47%), to central nervous system-related processes in 29 (44%), and to unknown causes in 6 (9%). For non-melanoma patients, death was attributable to systemic disease in 45 (68%), to central nervous system-related processes in 17 (26%), and to unknown causes in 4 (6%). Significantly improved survival (P = 0.002) was observed in patients with controlled systemic disease. No significant difference in survival could be ascertained for patients presenting with up to four lesions, although patients with a total tumor volume greater than 9 cc had shortened survival. No survival benefit could be demonstrated for whole-brain radiotherapy administered either concomitantly or after radiosurgery. CONCLUSION: Factors correlated with significantly improved survival included controlled systemic disease and non-melanoma histology. We found no significant survival benefit that could be discerned from adjuvant whole-brain radiotherapy in this patient group.

Radiosurgical salvage therapy for patients presenting with recurrence of metastatic disease to the brain.

OBJECTIVE: Radiosurgery has emerged as an important modality in the management of metastatic disease to the brain. A number of groups have published results suggesting that high local control rates can be achieved, with improvements in overall survival that rival the results of open surgical treatment. Typically, however, whole-brain radiotherapy has been used in the salvage therapy of patients who have undergone previous craniotomy or radiosurgery. We describe our experience with radiosurgical salvage in this group of patients. METHODS: From August 1994 to February 1999, 190 patients with brain metastasis were treated with gamma unit radiosurgery at our institution. A subset of 45 patients, who underwent radiosurgical salvage for new tumors in a region remote from an initially treated tumor, form the population base for this study. The usual criteria for repeat treatment were recurrence with five or fewer discrete lesions outside of the previously treated radiosurgical volume and Karnofsky Performance Scale score of at least 70. Survival and freedom from progression were measured from the time of radiosurgical treatment and were computed by the Kaplan-Meier product-limit method. Two or more curves were compared using the log-rank method. RESULTS: In this subgroup of patients, a total of 176 tumors were treated. The median time from first radiosurgical procedure to first salvage was 17.4 weeks. Median survival from the second radiosurgical intervention was 28 weeks. Of the 45 study patients, 34 patients underwent a single salvage procedure, 10 patients underwent two salvage procedures, and 1 patient had three salvage procedures. The actuarial freedom from progression for treated tumors at 52 weeks was 92.4%. Patients undergoing upfront whole-brain irradiation were less likely to require salvage therapy (P = 0.008). There were 33 deaths after salvage radiosurgery during the reporting period. Central nervous system causes accounted for 13 deaths, whereas 19 deaths resulted from systemic disease. The cause of death in one patient could not be determined. No statistically significant advantage in overall survival could be demonstrated in patients treated with whole-brain irradiation. CONCLUSION: Radiosurgical salvage represents a valuable means of treatment for central nervous system recurrence for patients who have undergone previous treatment for metastatic disease to the brain. Whole-brain irradiation may reduce the need for salvage therapy, but no advantage in overall survival could be demonstrated in this subgroup.

Balloon-protected carotid angioplasty.

OBJECTIVE: We describe a method of protecting the distal cerebral circulation during carotid angioplasty and report results using the technique in 17 procedures. METHODS: Eleven men and five women with carotid stenoses ranging in severity from 70 to 95% underwent the procedure. The technique was used bilaterally in one patient. A compliant silicone balloon was used to occlude the distal internal carotid artery during the angioplasty phase, when the largest number of emboli are generated. After angioplasty, debris was then flushed into the external circulation while the occlusion balloon remained inflated. The subsequent passage of an exchange guidewire through the angioplasty catheter, with the occlusion balloon deflated, allowed continuous guidewire access across the area of stenosis and facilitated the subsequent placement of a stent. RESULTS: The technique was successful in 16 (94%) of 17 procedures. In the one patient in whom the occlusion balloon could not be advanced across the stenosis, the patient experienced a transient ischemic attack after subsequent angioplasty that was performed without protection. Otherwise, no complications occurred among the 15 patients undergoing successful, balloon-protected angioplasty. Inflation times for the occlusion balloon did not exceed 5 minutes in any patient. CONCLUSION: This method of cerebral protection prevents the intracranial embolization of thrombus and atherosclerotic debris, while allowing continuous guidewire access across the site of stenosis. The success of this technique and a similar method used by Theron et al. supports the use of balloon protection as a means of reducing the risk of stroke associated with carotid angioplasty.

Parent vessel Guglielmi detachable coil herniation during wide-necked aneurysm embolization: treatment with intracranial stent placement: two technical case reports.

OBJECTIVE AND IMPORTANCE: Despite recent advances in technology, parent vessel coil herniation occasionally complicates successful Guglielmi detachable coil embolization, particularly in wide-necked aneurysms. We report endovascular stent deployment performed in two patients specifically to treat this complication. CLINICAL PRESENTATION: Two patients underwent Guglielmi detachable coil embolization of cavernous segment aneurysms. Both developed coil herniation into the internal carotid artery. In one patient, the herniation occurred during the initial procedure; in the other, it was discovered in a delayed fashion during a follow-up examination for ocular symptoms. INTERVENTION: In both patients, endovascular stent deployment was performed to isolate the herniated portion of the coil from the internal carotid lumen. Follow-up angiography at 6 months demonstrated no aneurysm recanalization and no stenosis of the parent internal carotid artery in the stented region in either patient. CONCLUSION: The use of intraluminal stents has been reported to be a helpful technical adjunct to the conventional endovascular treatment of aneurysms and balloon angioplasty. One additional indication for the use of this technology is sequestering herniated coils from the lumen of the parent artery to reduce potential embolic or occlusive sequelae.

Carotid stenosis in a multiethnic population.

BACKGROUND: Carotid stenosis is an important, treatable cause of stroke. Several population-based studies have shown ethnic differences in the prevalence of carotid atherosclerosis. This study was performed at a large multiethnic hospital to clarify these differences. METHODS: One thousand six carotid artery ultrasounds performed by the Department of Radiology at Los Angeles County General Hospital over a 4-year period were reviewed. Patients were classified as Caucasian (n=151), Hispanic (n=515), Black (n=173), or Asian (n=167) by self-declaration and birthplace. Carotid stenosis was defined as mild (1% to 39%), moderate (40% to 59%), severe (60% to 79%), critical (80% to 99%), or total (100%). RESULTS: Twenty and one-half percent of Caucasian patients had greater than 59% stenosis compared with 10.1% of Hispanics, 8.7% of Blacks, and 10.7% of Asians (P<0.001). Nine and two-tenths percent of Caucasians had greater than 79% stenosis compared with 4.3% of Hispanics, 2.9% of Blacks, and 2.8% of Asians (P<0.001). There were no significant differences in age or gender representations between ethnic groups, and the indications for ordering carotid duplex sonography also did not vary by race. Caucasians and Blacks had a higher prevalence of cardiac disease, smoking, and heavy alcohol abuse. Hispanics had higher rates of diabetes. CONCLUSIONS: These results indicate that significant differences in the degree of carotid stenosis exist among ethnic groups. Caucasian patients in our series showed a statistically higher likelihood of having a severe or critical level of stenosis. These findings may have implications for the allocation of health care resources as ethnic minorities compose a greater proportion of the population.

Examination of the spatial and temporal distribution of sensory cortical activity using a 100-electrode array.

This paper introduces improved techniques for multichannel extracellular electrophysiological recordings of neurons distributed across a single layer of topographically mapped cortex. We describe the electrode array, the surgical implant techniques, and the procedures for data collection and analysis. Neural events are acquired through an array of 25 or 100 microelectrodes with a 400-microm inter-electrode spacing. One advantage of the new methodology is that implantation is achieved through transdural penetration, thereby reducing the disruption of the cortical tissue. The overall cortical territory sampled by the 25-electrode array is 1.6 x 1.6 mm (2.56 mm2) and by the 100-electrode array 3.6 x 3.6 mm (12.96 mm2). Using a recording system with 100 channels available, neural activity is simultaneously acquired on all electrodes, amplified, digitized, and stored on computer. In our data, average peak-to-peak signal/noise ratio was 11.5 and off-line waveform analysis typically allowed the separation of at least one well-discriminated single-unit per channel. The reported technique permits analysis of cortical function with high temporal and spatial resolution. We use the technique to create an 'image' of neural activity distributed across the whisker representation of rat somatosensory (barrel) cortex.

Intraoperative angiography in the management of pediatric vascular disorders.

We reviewed our experience with intraoperative angiography in the management of 7 cerebral aneurysms and 15 arteriovenous malformations (AVMs) in children over the past 5 years. The patients ranged from 4 months to 18 years of age with a mean age of 9 years. In 4 of the 22 cases, angiography provided information that led to changes during surgery. In 3 cases, the intraoperative angiogram revealed residual AVMs that were then completely resected. In 1 patient with an anterior circulation aneurysm, intraoperative studies revealed findings which resulted in clip repositioning. Intraoperative angiography added a mean of 43 (+/-19) min to the operative time, with a mode of 40 minutes. There was 1 complication, a groin hematoma that readily resolved. Intraoperative angiography prolongs to operative course; however, it is a useful adjunct to the management of vascular disorders in children. We now routinely use and recommend intraoperative angiography to assist with the surgical management of vascular malformations in children.

Stereotactic radiosurgery in the treatment of metastatic disease to the brain.

We review 190 consecutive patients with 434 metastatic tumors treated by gamma knife stereotactic radiosurgery, from August 1994 to February 1999. Median actuarial survival for all patients was 34 weeks. Factors correlated with significantly improved survival included controlled systemic disease and nonmelanoma histology. We found that no significant survival benefit could be discerned from adjuvant whole brain radiotherapy in this patient group. Survival was not statistically different for patients initially presenting with 1-4 metastases at initial treatment.

Hypervascular acoustic neuroma.

The authors present a patient with a large acoustic neuroma that exhibited an unusual vascular architecture. Magnetic resonance imaging demonstrated multiple flow voids in and around the mass. At surgery, intra- and extratumoral vascularity was arterialized due to luxurious shunting. Two attempts at removal produced severe engorgement and pulsatility of the surrounding brain, dramatically narrowing the operative exposure. Piecemeal resection of the tumor seemed to redistribute blood flow resulting in engorgement of the surrounding brain, analogous to perfusion breakthrough following AVM resection. Treatment strategies similar to those used for AVM resection may be indicated when encountering a hypervascular tumor.

Embolization of neurosurgical lesions involving the ophthalmic artery.

OBJECTIVE: A number of anteriorly located cranial base and extracranial lesions receive their vascular supply wholly or in part from the ophthalmic artery, and embolization of the ophthalmic artery can be helpful in the management of these lesions, either as the primary treatment or as an adjunct to surgery. We present situations in which the embolization of lesions involving the ophthalmic artery was performed to effect a partial or total cure of the lesion. METHODS: Twelve patients underwent a total of 15 embolization attempts on lesions involving the ophthalmic artery. Four patients had arteriovenous malformations of the orbit, four had dural arteriovenous fistulae, two had orbital meningiomas, one had a planum sphenoidale meningioma, and one had a juvenile nasal angiofibroma. In each case, a Tracker No. 18 microcatheter (Target Therapeutics, Inc., Fremont, CA) was navigated into the ophthalmic artery using a steerable guidewire and digital road mapping. Embolic agents included polyvinyl alcohol particles ranging from 350 to 1500 microm in diameter, 2-mm platinum microcoils, and n-butyl-cyanoacrylate. In 12 of 15 cases, lidocaine and amytal provocation tests were conducted before any attempt at embolization to assess the role of the ophthalmic artery in vision. RESULTS: Embolization was successfully performed in the 14 situations in which it was attempted. Positive results of two lidocaine/amytal tests were noted. In one case, embolization was not attempted. In the other case, a larger caliber embolic agent (2-mm platinum coils) was used. A single transient decrease in visual acuity lasting 4 days was the only embolization-related complication. CONCLUSION: Proper case selection, judicious use of embolic agents, and use of provocative testing can result in safe embolization of lesions supplied by the ophthalmic artery.

Iatrogenic vertebrobasilar insufficiency after surgery of the subclavian or brachial artery: review of three cases.

OBJECTIVE AND IMPORTANCE: Vertebrobasilar insufficiency resulting from disease of the subclavian artery is well recognized. Usually, this occurs as the "subclavian steal" syndrome in the context of chronic subclavian stenosis and is consequently well tolerated because of collateralization. Acute disruption of the hemodynamics of the aortic arch vessels, however, can produce disastrous sequelae. CLINICAL PRESENTATION: We present three cases of iatrogenic vertebrobasilar insufficiency sustained as complications of surgery of the left subclavian artery or its distal continuation. The cases were chosen from a review of approximately 400 emergency neurosurgery consultations requested at the Los Angeles County Hospital between November 1995 and February 1996. INTERVENTION: The first patient underwent repair of a traumatic brachial artery occlusion and awoke postoperatively with bilateral cortical blindness, right hemiparesis, and multiple cranial nerve deficits that were most likely caused by acute subclavian steal. The second underwent removal of a subclavian embolus and developed bilateral cerebellar infarction leading to persistent coma, possibly from inadvertent embolization of the vertebral artery during surgery. The third underwent resection and bypass grafting of a subclavian aneurysm. Good backflow was reported when the vertebral artery was disarticulated from the subclavian artery, and this vessel was not reimplanted into the graft. The patient suffered massive cerebellar infarction leading rapidly to brain death. CONCLUSION: There are myriad ways in which the inherent redundancy of the vertebrobasilar system may be jeopardized, and when this protective mechanism fails, the results can be disastrous. Flow through the vertebral arteries may be compromised by thrombosis, embolization, dissection, inappropriate ligation, excessive head rotation, hypotension, vasospasm, or acute subclavian steal. These examples illustrate the importance of understanding the complex physiology of posterior fossa circulation as the basis of pre-, intra-, and postoperative management of patients undergoing surgery of the subclavian artery.

Carotid angioplasty and stenting in high-risk patients.

BACKGROUND: To examine our initial experience in carotid stenting (CS) for the prevention of stroke in patients with high-grade carotid stenoses. METHODS: The authors performed 26 CS procedures in 25 carotid vessels in 22 patients over a 15-month period. All carotid stenoses treated, except one, were 70% or greater. Of all CS procedures, 84% were performed for obstructing atherosclerotic plaques. CS was performed in one patient each for carotid dissection and pseudoaneurysms caused by a gunshot wound, post-radiation stenosis, post-carotid endarterectomy (CEA) restenosis, and a flow-obstructing post-CEA intimal flap. Of all patients, 68.2% were symptomatic, with a history of stroke or transient ischemic attacks ipsilateral to the treated carotid artery. In addition, 36.4% of our patients were either hospitalized or required skilled nursing care before CS because of severe neurologic deficits. Using the Sundt CEA-risk classification system, 59.1% of our patients were classified as Grade III and 40.9% were Grade IV pre-CS. All but one patient had either a compelling medical or anatomic reason for endovascular treatment of their carotid disease. We used both Wallstents and Palmaz stents, and all procedures were performed via the transfemoral route. Three procedures were performed in conjunction with detachable platinum coil embolization for multiple carotid pseudoaneurysms, a residual carotid "stump" after previous ICA thrombosis, and an ipsilateral MCA saccular aneurysm. RESULTS: We had a 96.2% procedural technical success rate. There was one death in our series 3 weeks post-CS attributable to myocardial infarction. Despite a high 30-day combined death, stroke, and ipsilateral blindness rate of 27.3% (6/22 patients), only two ipsilateral strokes directly related to CS occurred (7.7% per procedures performed) from which one patient recovered fully within 5 days. The average follow-up post-CS was 5.9 months (range, 3 weeks-15 months). Of successfully treated vessels, 58.3% have undergone 6-month follow-up vascular imaging, which has revealed a 14.3% rate of occlusion or restenosis greater than 50%. At or beyond 1 month post-CS, 19 of 21 surviving patients (90.5%) were ambulatory, fluent of speech, and independent, and none has thus far suffered a delayed stroke or TIA. CONCLUSION: CS seems to be a reasonable alternative to medical management for the treatment of carotid disease in patients deemed to be poor candidates for standard carotid surgery. Longer term follow-up is necessary to assess the durability of carotid revascularization using CS.

Endovascular coil occlusion of a traumatic basilar-cavernous fistula: technical report.

OBJECTIVE AND IMPORTANCE: We describe an unusual case of an 8-year-old male patient presenting with a traumatic basilar artery aneurysm associated with a basilar-cavernous fistula. CLINICAL PRESENTATION: The fistula occurred as the result of an accident involving a vehicle and a pedestrian. The patient originally presented in a coma and with a dense left hemiparesis. INTERVENTION: The traumatic basilar aneurysm and basilar-cavernous fistula were successfully occluded by endovascular coil embolization in two sessions. By 6 months after injury, the patient had made an excellent neurological recovery, requiring only a left leg brace for walking. CONCLUSION: Endovascular coil embolization provided an effective treatment option in the case of this complex and unusual arteriovenous fistula. We discuss the radiological and clinical features of related traumatic neurovascular lesions.

Coil embolization of a trigeminal-cavernous fistula.

A 53-year-old woman spontaneously incurred a right trigeminal artery-cavernous sinus fistula, manifested by an intracranial bruit and right sixth nerve palsy. This lesion was successfully managed by coil embolization via the transvenous and transarterial routes.

Carotid endarterectomy compared with angioplasty and stenting: the status of the debate.

Endarterectomy is the treatment of choice for patients with symptomatic stenosis of the internal carotid artery. Recently, debate has arisen over the potential benefits of endovascular techniques. Although retrospective analyses of angioplasty and stenting procedures suggest comparable clinical efficacy to endarterectomy, prospective evaluation is pending. The authors review the status of the debate and discuss those issues on both sides that are particularly contentious and clinically relevant.