Early intracerebral hemorrhage complicating the successful occlusion of a carotid-cavernous fistula.

SUMMARY: A 74-year-old woman with a direct carotidcavernous fistula secondary to aneurysm rupture was treated by endovascular balloon occlusion of the fistula. Two days later, she suffered an intracerebral hemorrhage ipsilateral to the treated carotid cavernous fistula, perhaps due to normal perfusion pressure breakthrough. Normal perfusion pressure breakthrough has been described as a cause of hemorrhage following treatment of arteriovenous malformations (1) and carotid stenosis (2,3). We report an unusual case of therapeutic endovascular occlusion of a direct carotid-cavernous fistula complicated by hemorrhage presumably caused by normal pressure perfusion breakthrough.

Fifty years of the congress of neurological surgeons: foundations, objectives, and legacies.

As the Congress of Neurological Surgeons (CNS) approaches its 50th anniversary, we review the genesis of our professional society, the environment in which it was created, and the legacies it has established. The CNS was the first nonexclusive, international neurosurgical organization with no ostensible limitations to membership. From its unpretentious origins, the CNS has grown remarkably in size and scope, yet it has remained focused on its original primary objectives: education, the young neurosurgeon, membership, and volunteerism for the benefit of our specialty. During its 50-year history, the CNS has established a number of lasting legacies that have positively influenced the development and maturation of our chosen specialty. Neurosurgery is unique in having benefited from two strong national member organizations to ensure representation of different generations and perspectives for policy-making, to provide for two comprehensive annual meetings and complimentary journals, to broaden the representation for neurosurgery in our interaction with outside agencies, and to minimize the cost of services provided on behalf of neurosurgeons.

Prevention of complications resulting from endovascular carotid sacrifice: a retrospective assessment.

OBJECTIVE: To determine the protective effects of various periprocedural interventions in the prevention of cerebral ischemia as a complication of endovascular carotid sacrifice (ECS). METHODS: Thirty-two cases of ECS performed at our institution, between October 1987 and July 1998, were reviewed. Fifteen patients underwent superficial temporal artery-to-middle cerebral artery bypass surgery. In 21 patients, the carotid artery was occluded proximal to the target lesion; and in 11 patients, a lesion trapping procedure was performed. Six patients were prophylactically anticoagulated, 14 received antiplatelet agents prophylactically, and 12 received no pharmacoprophylaxis. RESULTS: Among the six patients who were anticoagulated, there were no embolic events. Embolic events affected 4 of 14 patients receiving prophylactic antiplatelet agents, 2 of 12 patients receiving no pharmacoprophylaxis, 1 of 11 patients who underwent a trapping procedure, and 5 of 21 patients whose carotid artery was occluded proximal to the target lesion. Postocclusion cerebral ischemia developed in 7 of 15 patients who underwent bypass surgery, and in 1 of the remaining 17. CONCLUSION: Superficial temporal artery-to-middle cerebral artery bypass did not protect against postocclusion cerebral ischemia after ECS in this series (P = 0.01). Although the small number of patients studied precludes statistical validity (P = 0.29), the trends suggest that antiplatelet agents provide no protection against postocclusion cerebral emboli after ECS. Prophylactic anticoagulation (P = 0.32) and lesion trapping (P = 0.12) may reduce the frequency of postocclusion embolic events after ECS; however, because of the small number of patients, statistical significance could not be demonstrated.

Surgical management of angiographically occult spinal dural arteriovenous fistulae (type I spinal arteriovenous malformations): three technical case reports.

OBJECTIVE AND IMPORTANCE: Spinal dural arteriovenous fistulae (Type I spinal arteriovenous malformations [AVMs]) have been recognized as a treatable cause of progressive myelopathy. The diagnosis and characterization of these lesions rest heavily on spinal angiography. CLINICAL PRESENTATION: We present three patients whose clinical presentations were consistent with a spinal dural AVM but whose spinal angiographic results were negative. INTERVENTION: The surgical treatment of these angiographically occult spinal AVMs is described. In retrospect, in each case, the feeding vessel to the AVM was injected but not seen. CONCLUSION: Some spinal dural arteriovenous fistulae will be angiographically occult. If the clinical and radiographic presentations strongly suggest the presence of an arteriovenous fistula, surgical exploration should be considered.

Microsurgical anatomy of the artery of Adamkiewicz and its segmental artery.

OBJECT: The blood supply of the lower spinal cord is heavily dependent on the artery of Adamkiewicz, which characteristically originates from one of the thoracolumbar segmental arteries. The aforementioned artery is of enormous clinical, surgical, and radiological importance, and the goal of this study was to elucidate the course and branches of the segmental artery that gives rise to this important vessel. METHODS: In this cadaveric, microsurgical anatomical study, the authors investigate and describe the course and branches of the artery of Adamkiewicz and the segmental branch from which it ultimately originates. A review of the literature is provided. CONCLUSIONS: By documenting the microsurgical anatomy of these important vessels, this study facilitates an understanding of the anatomy that will aid in treatment planning for surgery of various lesions in this area.

Microsurgical anatomy of the dorsal cervical nerve roots and the cervical dorsal root ganglion/ventral root complexes.

BACKGROUND: It is known that a "dissociated motor loss" of the deltoid muscle can occur with disconcerting frequency after cervical spine surgery. The etiology of this entity is in question. We conducted an anatomic study to identify anatomic factors that might predispose C5 to injury. METHODS: We studied 128 dorsal cervical nerves and root ganglion/ventral root complexes in 10 adult cadavers. At each cervical level the following data were recorded: number of rootlets, range of width of rootlets, length of DREZ, cranial angles of the superior and inferior rootlets with the spinal cord, length of the superior and inferior rootlets, dimensions of the foramina, dimensions of the dorsal root, dimensions of the dorsal root ganglion (DRG)/ventral root (VR) complex, and the blood supply to the DRG. The histology at the site of compression was also examined. Statistical analysis was conducted using the single factor-repeated measures analysis of variance. RESULTS: We found that, 1) the C5 superior dorsal rootlets angle less inferiorly from the cervical cord than the other dorsal cervical roots (p=0.001), 2) the majority of the DRG/VR complexes from C3 to C6 were compressed by the vertebral artery (73%), 3) the C5 DRG/VR complex was compressed to the greatest extent (77.6%, p=0.3519), and 4) the ganglionic artery was more frequent at C4, C5, and C6. CONCLUSION: To our knowledge, the second finding has not been reported previously. The first and third findings may help explain why C5 is more vulnerable to injury.

Transvenous embolization as the primary therapy for arteriovenous fistulas of the lateral and sigmoid sinuses.

PURPOSE: We report on the evolution in one institution from transarterial embolization for the treatment of dural arteriovenous fistulas of the lateral and sigmoid sinuses to the safer and more durable technique of transvenous endovascular therapy for the majority of these lesions. METHODS: Arterial, venous, and combined embolizations were performed for 24 fistulas of the lateral and sigmoid sinuses between August 1991 and December 1996. The patients were followed up clinically for 2 to 63 months, with a mean follow-up period of 30 months. RESULTS: Nine patients had arterial embolization without transvenous treatment: five of the nine had angiographic and clinical obliteration of their fistulas; two of the nine, with unusual lesions, required surgery; and the remaining two had recurrences and were not retreated. Seven patients had both arterial embolization and coil embolization (packing) of the dural sinuses, four after arterial embolization had failed to cure the lesions; in all seven, the fistulas were obliterated angiographically and clinically. Eight patients had only transvenous coil embolization of the dural sinuses; all eight were cured. One patient had minimal arterial embolization during the primary venous embolization procedure. Complications occurred in two patients, both related to arterial embolization with ethanol. CONCLUSION: Our experience suggests that arterial embolization of dural arteriovenous fistulas of the lateral and sigmoid sinuses is associated with a low cure rate and high rate of recurrence, whereas transvenous endovascular packing of the involved segment of the sinus results in a high cure rate that obviates arterial embolization or surgical excision in most cases.

Lipomatous glioneurocytoma of the posterior fossa with divergent differentiation: case report.

OBJECTIVE AND IMPORTANCE: We report a case of a posterior fossa neuroepithelial tumor with unusual clinical presentation, magnetic resonance imaging appearance, and morphological features. CLINICAL PRESENTATION: This 66-year-old man presented with a history of gait ataxia, dizziness, and tinnitus and was found to have a large tumor in the posterior fossa and cerebellopontine angle. INTERVENTION: Gross total excision of the tumor was accomplished. Histologically, the most unique features were macrovesicular accumulations of lipid, giving the tumor (at least focally) an appearance virtually identical to that of mature adipose tissue. Evidence of biphasic neuronal and glial differentiation was noted by immunohistochemistry and electron microscopy. CONCLUSION: A literature review is presented. Diagnostically, this neoplasm seems to fit in a unique group of rarely described, lipomatous neuroectodermal tumors that show divergent neuronal and glial differentiation.

Efficacy and biocompatibility of a photopolymerized, synthetic, absorbable hydrogel as a dural sealant in a canine craniotomy model.

OBJECT: A canine craniotomy model was used to evaluate the dural sealing efficacy and biocompatibility of a novel, synthetic, bioresorbable hydrogel. METHODS: Bilateral craniotomies were performed in 24 dogs assigned to six survival periods. In each animal a parasagittal durotomy was created and then repaired. At the treatment sites the hydrogel sealant was applied over the dural repair and photopolymerized. The repair was tested for leaks to 20 cm H2O by using a Valsalva maneuver. At the control sites the incisions were sutured and tested for leaks only. After uneventful survival periods, the leak test was repeated in three of the four animals in each group. Bone-dura adhesion was evaluated, after which the dura and underlying brain were removed, fixed, and examined histologically. En bloc histological investigation was performed on a specimen obtained from the fourth animal in each group. Over a 56-day period, 18 treated sites were tested for leaks. A leak was detected at a site remote from that of the repair in one animal; this was excluded from analysis. Thus 17 of 17 treated sites remained free of leaks. On the control side of one animal, there was a leak from a new dural tear at the cranial end of the durotomy, which occurred when the bone flap was removed. This site was also excluded from analysis. Eleven of 17 leak-tested control sites remained free of leaks over the study period. Bone-dura adhesions occurred in 15 of 19 control sites and had a mean adhesion score of 1.37 (range 0-4), whereas adhesions occurred in 10 of 19 treated sites with a mean adhesion score of 0.84 (range 0-3). No cortical reaction was noted. CONCLUSIONS: This novel hydrogel sealant is efficacious in sealing dural repair sites measuring up to 2 mm. Healing of the underlying dura is not compromised and exposed cortical tissue is not altered histologically.

Cranial bone graft to reconstruct the mandibular condyle in Macaca mulatta.

PURPOSE: The purpose of this study was to evaluate the efficacy of cranial bone grafts to reconstruct the mandibular condyle in a nonhuman primate model. MATERIALS AND METHODS: The right mandibular condyle was resected in eight female, adult, nongrowing monkeys (Macaca mulatta) and the mandible was reconstructed with autogenous, full-thickness cranial bone harvested from the frontal area of the skull and stabilized with rigid fixation. Joint function, facial symmetry, and occlusion were evaluated preoperatively and over the course of 1 year postoperatively. The height of the bone graft was measured intraoperatively and at 1 year postoperatively. RESULTS: Seven monkeys survived for 1 year. The animals' weights were stable postoperatively. There were no statistically significant changes in maximal incisal opening or lateral excursion, as well as no statistically significant changes in facial symmetry or occlusion. On average, the total decrease in height of the graft was 0.7 +/- 0.9 mm (P = .07). CONCLUSION: After reconstruction of the mandibular condyle in Macaca mulatta, full-thickness cranial bone grafts provided a functional joint that resisted resorption. Cranial bone may therefore provide a suitable alternative to other autologous or alloplastic graft materials for reconstruction of the human mandibular condyle in nongrowing patients.

Arterial saccular aneurysm model in the rabbit.

Saccular aneurysms arising from the common carotid artery in the neck at the origin of the internal carotid artery were created in male rabbits using the stump of a ligated external carotid artery. These stumps were intraluminally perfused with varying concentrations of porcine pancreatic elastase for 45 minutes via a microcatheter introduced into the femoral artery. The aneurysms were allowed to mature for 2 to 12 weeks. Gross examination and histologic studies confirmed the presence of an aneurysm in all 15 experiments. Ninety-two percent (12 of 13) of the aneurysms studied by postoperative angiography were shown to be angiographically patent: 40% of all aneurysms were noted to be patent at harvest; and the remainder showed evidence of intraluminal thrombus. On histologic examination, all aneurysms showed complete loss of elastic lamina without evidence of fibrosis or scarring.

Treatment of experimental aneurysms using collagen-coated microcoils.

Endovascular treatment of certain surgically difficult aneurysms is currently performed using fibered microcoils or electrolytically detachable microcoils to obliterate these lesions by forming an intra-aneurysmal thrombus. Unfortunately, this treatment option results in a significant incidence of incomplete obliteration of treated aneurysms. A thrombus can recanalize, resulting in further aneurysm growth and subsequent rupture. Nineteen aneurysms were surgically created in 10 pigs using jugular venous pouches. The aneurysms were allowed to mature for periods of 7 days to as long as 11 weeks prior to embolization. Fourteen remained patent for embolization. The aneurysms were then embolized (9 with collagen-coated microcoils, 5 with dacron-fibered platinum microcoils). Follow-up angiograms were obtained prior to sacrifice at 1, 3, 6, 9, and 12 weeks postembolization, and the embolized aneurysms and parent vessels were harvested for histopathological studies. The current study was designed to evaluate the potential efficacy of collagen-coated microcoils in providing an enduring therapy for aneurysms by comparing this new embolic device with the standard dacron-fibered platinum microcoils in a swine common carotid artery side wall aneurysm model. The aneurysms treated with collagen microcoils were completely obliterated with a collagen-rich fibrous scar with no histological evidence of residual thrombus or recanalization. Additionally, after treatment of experimental aneurysms with collagen microcoils, re-endothelialization across the former aneurysm neck was seen. In contrast, aneurysms embolized with dacron-fibered microcoils contained persistent thrombus surrounded by a relatively immature scar with residual aneurysmal lumen and lack of endothelium.(ABSTRACT TRUNCATED AT 250 WORDS)

Microsurgical revascularization of the ophthalmic artery.

We have developed and performed a microsurgical arterial anastomosis to revascularize the ophthalmic artery in patients with ischemic visual loss, resulting in improvement in visual function. A detailed description of the surgical procedure is discussed as well as the indications for surgery in these cases. An ischemic etiology of visual impairment was predicted by binocular fundus reflectometry, a noninvasive technique to indicate ocular perfusion abnormalities. Encouraging early results suggest that such a revascularization procedure may provide a therapeutic option for a particular group of patients with progressive ischemic visual loss.

Natural history of giant intracranial aneurysms and indications for intervention.

Giant intradural aneurysms are associated with an extremely grave natural history, yet remain potentially curable. Those aneurysms located on the intracavernous segment of the internal carotid artery are associated with a more benign natural history but frequently present with intractable cranial neuropathy requiring intervention. Proper current management requires a multidisciplinary approach through which the therapeutic goals are clearly defined. The treatment of giant intracranial aneurysms must be individualized after considering the various therapeutic options available to the multidisciplinary team. The cost of managing these complex lesions can be reduced by minimizing complications. Future advances in our ability to better manage patients with giant intracranial aneurysms will require careful assessment of outcome parameters.

Surgical management of arteriovenous malformations in the region of the ventricular trigone.

The results in the surgical management of 26 patients with arteriovenous malformations intimately related to the trigone of the lateral ventricle are presented. Three operative approaches were used in the series, including a transtemporal route through the inferior or middle temporal gyrus (15 patients), an interhemispheric approach (8 patients), and a transcortical parieto-occipital approach (3 patients). The surgical approach was chosen on the basis of the relationship of the arteriovenous malformation to the trigone, the presence and location of associated hematoma, and preoperative neurological deficits. This report emphasizes the use of surgical adjuncts that are instrumental in the management of these challenging lesions, including magnetic resonance imaging for precise localization and operative planning, preoperative embolization to obliterate deep arterial supply, and intraoperative ultrasound and angiography to aid in localization and to document complete excision of the arteriovenous malformation before closure. The results of the management of these 26 patients are as follows: 21 had no or minor neurological deficits and were able to resume premorbid activities; 2 had a fair result, being independent but unable to resume their premorbid occupation; 2 had a poor result and were dependent as the result of an incapacitating neurological deficit; and 1 died.