Stents for intracranial aneurysms: the beginning of a new endovascular era?
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Publications and source records attributed to G Lanzino.
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UNLABELLED: OBJECTIVE/IMPORTANCE: One of the most severe complications of craniosynostosis repair is dural sinus laceration. Massive hemorrhage and air embolism are potentially life-threatening sequelae that can result from such an event. The aberrant anatomy of patients with craniosynostosis only accentuates this risk, because separation of the calvaria from the underlying dura is often performed without direct visualization of the sinuses. METHODS: Three-dimensional computed tomography was combined with computed tomographic angiography in the preoperative assessment of patients with craniofacial abnormalities. RESULTS: A clear understanding of the dural sinus anatomy in relation to the overlying bony landmarks became available to the operating surgeon. Six patients underwent this procedure, with excellent visualization of the bony and sinus anatomy achieved in all cases. CONCLUSION: It is thought, that the benefit of combining these procedures has been significant by allowing the visualization of the dural sinus anatomy and overlying bony landmarks. This procedure conveys minimal concomitant morbidity or expense to the patient, yet offers valuable insight toward operative planning and complication avoidance.
OBJECTIVE AND IMPORTANCE: Endovascular stents have been successfully used in the treatment of fusiform and dissecting aneurysms of the peripheral circulation and extracranial carotid and vertebral arteries. Technical limitations related to the inability to navigate the stent and the delivery system through tortuous vascular segments has limited their application with intracranial lesions. Availability of new flexible and pliable stent systems might overcome these difficulties. CLINICAL PRESENTATION: A 49-year-old woman presented with a dissecting pseudoaneurysm of the horizontal portion of the petrous internal carotid artery that increased in size, as revealed by serial angiographic studies. INTERVENTION: The aneurysm was treated by deploying a new flexible stent across the aneurysm neck and by then packing the aneurysm sac with Guglielmi detachable coils that were delivered by a microcatheter positioned through the stent struts into the aneurysm lumen. CONCLUSION: New flexible stents can be used to treat intracranial internal carotid artery aneurysms in difficult-to-access areas, such as the horizontal petrous segment. The stent may disrupt the aneurysm inflow tract, thereby inducing stasis and facilitating intra-aneurysmal thrombosis. In addition, the stent acts as an endoluminal scaffold to prevent coil herniation into the parent artery, which allows tight packing of even wide-necked and irregularly shaped aneurysms. The stent may also serve as a matrix for endothelial growth. We think this new generation of flexible stents and the use of this described technique will usher in the next era of endovascular management of intracranial aneurysms.
Guglielmi detachable coil (GDC) treatment for complicated cerebral aneurysms is an attractive option that has become widely accepted in recent years. This technique is usually considered only if the patient harbors an aneurysm that is not a good candidate for surgical clipping. However, the definition of "surgical candidate" varies among institutions, and many patients worldwide are being treated with GDCs as primary therapy. Although most centers currently perform follow-up angiography at 6 months to 1 year, others do not routinely perform it after an initially good result. The authors present a case that indicates longer follow up may be necessary and illustrates some of the pitfalls of GDC treatment. This 56-year-old man presented to the emergency room with a Hunt and Hess Grade II subarachnoid hemorrhage and was found to have a wide-necked basilar apex aneurysm. Because of associated medical comorbidities, it was decided to treat the aneurysm with endovascular techniques. The patient did well on follow-up angiography at 1 year postprocedure. However, at approximately 2 years follow up, the aneurysm was demonstrated to have dramatically recanalized and regrown, requiring open surgical intervention. Endovascular coiling was insufficient to treat this aneurysm and complicated definitive surgical management because a large coil mass had been placed in the operative field. It can be inferred from this case that angiographic follow up of these types of lesions may be beneficial up to 2 years after GDC treatment.
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Fibrosarcomas involving the sella turcica are rare lesions and, when encountered, have been associated with previous radiation of a pituitary adenoma. Although primary intracranial fibrosarcomas are well recognized, no case of primary fibrosarcoma of the sella turcica has been reported to date. We describe here a patient who presented with a 2-month history of headache, visual disturbances, and diabetes insipidus. Her past medical history was unremarkable, with no radiation therapy. Magnetic resonance imaging revealed a sellar/suprasellar lesion that at surgery appeared firm in consistency. A radical removal of the mass was performed through a transsphenoidal approach. The patient recovered promptly from the operation and 2 weeks later, given the aggressive histologic appearance of the lesion, underwent gamma knife radiosurgery. Seven months after diagnosis, the patient presented with local tumor recurrence. A subtotal surgical resection was performed, and additional postsurgical treatment is still under consideration. Although most often related to previous radiation of the pituitary gland, primary fibrosarcomas can occur in the sella. This possibility should be suspected in the differential diagnosis of sellar masses that lack the classical characteristics of the much more common pituitary adenomas.
Timing of surgery is one of the most important and controversial aspects in the management of the patient with a ruptured aneurysm. For each patient with a ruptured aneurysm, the treating physician is faced with a difficult decision: to operate acutely in order to avoid rebleeding despite the swollen brain, or to wait until the effects of the initial hemorrhage subside. The decision of whether or not to perform surgery acutely after subarachnoid hemorrhage (SAH) strongly affects the ability to prevent and treat some of the complications of SAH. Either approach, early or delayed surgery, has pros and cons. This article reviews the numerous factors that play a role in this delicate decision-making process.
Malformations of the human neocortex are commonly associated with developmental delays, mental retardation, and epilepsy. This study describes a novel neurologically mutant rat exhibiting a forebrain anomaly resembling the human neuronal migration disorder of double cortex. This mutant displays a telencephalic internal structural heterotopia (tish) that is inherited in an autosomal recessive manner. The bilateral heterotopia is prominent below the frontal and parietal neocortices but is rarely observed in temporal neocortex. Neurons in the heterotopia exhibit neocortical-like morphologies and send typical projections to subcortical sites; however, characteristic lamination and radial orientation are disturbed in the heterotopia. The period of neurogenesis during which cells in the heterotopia are generated is the same as in the normotopic neocortex; however, the cells in the heterotopia exhibit a "rim-to-core" neurogenetic pattern rather than the characteristic "inside-out" pattern observed in normotopic neocortex. Similar to the human syndrome of double cortex, some of the animals with the tish phenotype exhibit spontaneous recurrent electrographic and behavioral seizures. The tish rat is a unique neurological mutant that shares several features with a human cortical malformation associated with epilepsy. On the basis of its regional connectivity, histological composition, and period of neurogenesis, the heterotopic region in the tish rat is neocortical in nature. This neurological mutant represents a novel model system for investigating mechanisms of aberrant neocortical development and is likely to provide insights into the cellular and molecular events contributing to seizure development in dysplastic neocortex.
BACKGROUND: Age is considered an important limiting factor for surgical excision of parenchymal arteriovenous malformations (AVMs) and a more conservative therapeutic approach has been advocated in the elderly. There are no studies available investigating the long-term outcome after surgical excision of parenchymal AVMs in patients over 60 years of age. METHODS: We report the surgical outcome after excision of an AVM in a series of 13 consecutive patients older than 60 years. Medical records were analyzed retrospectively. RESULTS: Hemorrhage was the mode of presentation in all patients. Three patients were admitted in a comatose state. Surgery was performed within 1 week from the initial bleeding in seven cases and within 2 weeks in five cases. There were no deaths directly related to surgery in this series. However, one patient died as a result of an intracranial hemorrhage complicating preoperative embolization and another patient died 3 months after surgery from intervening medical complications. During the follow-up period (mean 46 months), three more patients had died 8, 19, and 48 months after surgery, respectively. Of the remaining eight patients, six are doing well and are independent in the activities of daily living. One patient is independent but requires supervision, and the remaining one was lost to follow-up. CONCLUSIONS: Age alone should no longer be considered a contraindication to treatment. In selected cases, surgery can be performed safely even in the elderly patient with an AVM. After surgical excision, elderly patients have the potential for several years of active life.
BACKGROUND: With increasing frequency, dissecting aneurysms of the intracranial arteries are recognized as a possible cause of subarachnoid hemorrhage (SAH). In the presence of a dissecting aneurysm, angiographic changes may be subtle at presentation and correct diagnosis often requires serial angiograms. We report a patient with a dissecting aneurysm of the anterior cerebral artery (ACA) causing SAH, in whom less invasive diagnostic tools, such as high-resolution computerized tomographic angiography (CTA) and magnetic resonance angiography (MRA), were helpful in confirming the diagnosis and in following the evolution of the dissection. CASE PRESENTATION: We present this 51-year old woman who experienced the sudden onset of severe headache without associated neurological deficits. Head CT showed SAH with blood in the interhemispheric fissure, suggesting a ruptured ACA aneurysm. Serial cerebral angiograms failed to demonstrate an aneurysmal sac, but showed evolving irregularities of the ACA consistent with a dissecting aneurysm. These findings were confirmed by CTA and MRA. The patient was treated conservatively and made an excellent recovery. A MRA obtained 2 months later showed slight improvement of the previously visualized ACA dilatation. CONCLUSION: Serial angiograms are often required to confirm the diagnosis and to follow the evolution of an intracranial dissection. With recent advances in neuroradiological techniques, however, critical information can be obtained by less invasive imaging studies, such as CTA and MRA.
Although neurologic changes after organ transplantation are often secondary to opportunistic infections or vascular insults, new pathological entities are emerging. We have recently encountered two patients who, a few days after liver and heart transplant, respectively, developed neurological signs and symptoms. Head computerized tomography (CT) scan showed nonenhancing areas of low attenuation, and magnetic resonance imaging (MRI) demonstrated multiple areas of increased signal intensity in the subcortical white matter on T2-weighted images. Stereotactic biopsy of the intracranial lesions was performed in one case. Light microscopic examination demonstrated only mildly edematous white matter. No infectious organisms were observed on light or electron microscopy. In one patient, follow-up MRI 3 months later showed almost complete resolution of the signal abnormalities. Both patients' clinical condition progressively improved. The neuroradiological abnormalities described are consistent with the 'reversible posterior leukoencephalopathy' syndrome associated with cyclosporine toxicity. The pathophysiology of these lesions is unclear; however, it has been suggested that cyclosporine causes an acute ischemic insult secondary to vascular spasm with resultant axonal swelling. This hypothesis is supported by the hypoattenuation seen on CT, the prolonged T2 relaxation seen on MRI, and the absence of contrast enhancement. Concomitant factors (such as hypocholesterolemia or associated therapy with high dose steroids) are important in the development of these lesions as in both of our patients cyclosporine levels were in the normal range. Fortunately, these lesions and the associated manifestations are most often reversible and regress with adjustments of cyclosporine dosage and/or correction of concomitant facilitating factors.
One hundred years ago, in 1896, Joseph Babinski published a preliminary report on "réflexe cutané plantaire" (cutaneous plantar reflex), which became widely known as the Babinski sign. However, Babinski did not view the description of the sign as his major achievement. Instead, he considered his greatest contribution to medicine to be his having "... indiqué la voie à Martel et à Vincent" (pointed the way to Thierry de Martel and Clovis Vincent, founders of French neurosurgery). Several of Babinski's manuscripts deal with neurosurgical problems. In 1900, 1 year before Alfred Fröhlich's description, Babinski gave the first account of the adiposogenital syndrome and its relation to pituitary-hypothalamic disorder. Many other original contributions ensued. These include a report on the relief of papilledema by surgical decompression in 1901, the successful removal (in collaboration with de Martel) of an intracranial meningioma in 1909, the description (again with de Martel) of a cerebellopontine angle tumor treated by surgical excision with good result in 1925, and several manuscripts concerning diagnosis and treatment of compressive spinal cord lesions. Babinski's dream to establish a department of neurosurgery became a reality shortly after his death. The Hôpital de la Pitie in Paris, where Babinski did most of his work, established the first French department of neurosurgery chaired by Babinski's pupil, Vincent.
OBJECTIVE AND IMPORTANCE: Hearing preservation has become an important issue in surgical procedures involving the cerebellopontine angle (CPA). Although several prognostic factors for hearing preservation in patients with "useful" preoperative hearing have been described, it is difficult to predict which patients have the potential for hearing preservation or recovery. Otoacoustic emission measurement is a new technique that allows recording of sounds produced by the cochlear outer hair cells as a normal byproduct of the receptor process and can be used to assess cochlear involvement in patients with hearing loss. CLINICAL PRESENTATION: We present the case of a 53-year-old patient with a recurrent arachnoid cyst of the CPA. She had noticed progressive severe hearing loss ipsilateral to the cyst that was confirmed by preoperative audiogram. TECHNIQUE: Otoacoustic emissions were obtained and were within normal limits on the involved side, suggesting that the cochlear outer hair cells were still intact and that the patient had the potential for hearing recovery. The CPA was decompressed by marsupialization of the cyst. Postoperative audiogram demonstrated a dramatic recovery of hearing to a normal level. CONCLUSION: Otoacoustic emissions clearly provide valuable information about the potential for hearing preservation/recovery after CPA surgery and have significant implications for the current neurosurgical management of these lesions.
PURPOSE: To assess the cost versus the benefit of routine cerebral angiography after surgery for ruptured aneurysms. METHODS: Decision tree and Markov analyses that used cohort simulation were conducted to determine the incremental cost:benefit ratio of routine postsurgical angiography. Input data for unexpected partially clipped and unclipped cerebral aneurysms were estimated from the literature for the following variables: frequency; annual rate of subsequent hemorrhage; morbidity and mortality rates of subsequent hemorrhage; efficacy and morbidity and mortality rates of subsequent surgery; and costs of subsequent surgery, angiography, subsequent hemorrhage of aneurysm, and rehabilitation. RESULTS; Baseline input variables resulted in an acceptable cost:benefit ratio for routine postsurgical angiography. However, essentially all of the benefit was derived from intervening in cases of unexpected unclipped aneurysms rather than partially clipped aneurysms. Isolated instances of angiography and subsequent surgery for unexpected partially clipped aneurysms yielded unacceptable cost:benefit ratios. Surgical costs had minimal effect on the analysis. CONCLUSIONS: When routine postsurgical angiography was performed primarily to diagnose and to subsequently operate on unexpected partially clipped aneurysms, the cost:benefit ratio was unacceptable. However, even low frequencies of unexpected unclipped aneurysms resulted in favorable cost:benefit ratios.
OBJECTIVE: Iron catalyzed generation of injurious free radicals has been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH). The present study assessed the effects of the iron chelator deferiprone on cerebral vasospasm in an in vivo rabbit model of SAH. METHODS: Twenty-four rabbits were assigned to three groups as follows: SAH plus placebo (n = 8), SAH plus deferiprone (n = 8), or control plus placebo (n = 8). Deferiprone was administered to an additional group of three rabbits that were not subjected to SAH. Drug administration was initiated 8 hours after SAH was induced and was repeated at 8-hour intervals. The animals were killed using perfusion-fixation 48 hours after SAH. Cross-sectional areas of basilar artery histological sections were measured by an investigator blinded to the treatment groups. RESULTS: In placebo-treated animals, the average luminal cross-sectional area of the basilar artery was reduced by 54% after SAH compared to controls (i.e., from 0.272 to 0.125 mm2). The vasospastic response after SAH was attenuated significantly in animals treated with deferiprone (0.208 mm2, representing a 24% reduction). CONCLUSION: Previous experimental studies suggested that iron chelation can be effective in attenuating cerebral vasospasm after SAH. Deferiprone is a recently developed iron chelator that has been extensively evaluated for the treatment of patients requiring chronic blood transfusions. The present study demonstrates that deferiprone is effective in attenuating experimental cerebral vasospasm. Because of its stability, lipophilicity, and ability to penetrate the blood-brain barrier, deferiprone represents an attractive candidate for the treatment of cerebral vasospasm.
OBJECTIVE: We intended to characterize the CT patterns of hemorrhage associated with ruptured posterior inferior cerebellar artery (PICA) aneurysms. MATERIALS AND METHODS: CT scans of 44 cases of angiographically confirmed ruptured saccular PICA aneurysms (4) aneurysms at the junction of the vertebral artery and the PICA and three distal PICA aneurysms) were retrospectively reviewed. All scans had been obtained within 2 days of the subarachnoid hemorrhage (SAH) (day 0 [less than 24 hr], 35 patients; day 1, eight patients; day 2, one patient). Presence or absence of hemorrhage in specific subarachnoid, intraventricular, and intraparenchymal locations was noted, as were the presence and degree of hydrocephalus. RESULTS: Posterior fossa SAH was present in 95% of cases. Isolated posterior fossa SAH was present in 30% of cases, but in no case was isolated supratentorial SAH present. Supratentorial SAH was present in 70% of cases. SAH involving the sylvian fissure or the interhemispheric region was present in 25% and 23% of cases, respectively. SAH along the convexity was present in 2% of cases. Intraventricular hemorrhage (IVH) with or without associated SAH was seen in 95% of cases, whereas isolated IVH was seen in 5% of cases. Hydrocephalus was present in 95% of cases and was moderate to marked in 70%. Both IVH and hydrocephalus were present in 93% of cases. CONCLUSION: Ruptured PICA aneurysms almost always coexist with hydrocephalus and IVH, as seen in 93% of cases, and almost never coexist with SAH along the convexity. The most common pattern of hemorrhage associated with such aneurysms includes IVH and posterior fossa hemorrhage. Extensive supratentorial SAH, in conjunction with posterior fossa SAH, is a common finding in patients with ruptured PICA aneurysms. SAH isolated to the posterior fossa is present in a sizeable minority of cases.
PURPOSE: To evaluate the imaging findings, possible pathogenesis, and frequency of hemorrhage near the tentorial surface of the cerebellum after supratentorial surgery. METHODS: Over a 5-year period, 13 patients with posterior fossa hemorrhage after supratentorial surgery were identified with postoperative CT studies, which were obtained in all patients after craniotomy. Four of the 13 patients also had postoperative MR examinations. Preoperative and postoperative radiologic studies and medical records were reviewed. RESULTS: All hemorrhages were located along the superior aspect of the cerebellum transversely oriented along the cerebellar fossa and fissures. None of the patients had coagulopathy or radiologic evidence of posterior fossa tumor or vascular malformation. None of the hemorrhages had an appearance typical of hypertensive hemorrhage. Ten patients (77%) had lumbar drains placed before surgery and all had epidural drains placed at the conclusion of surgery. One patient had surgery for a meningioma, and 12 had surgery for aneurysms. The frequency of hemorrhage after aneurysmal surgery was 3.5%. No neurologic deficits developed referable to the cerebellum. CONCLUSIONS: Hemorrhage should be viewed as a potentially benign sequela of surgery rather than as an indication of hypertension, aneurysm, or previously unrecognized vascular malformation or neoplasm.
OBJECTIVE: Cranioplasty using acrylic is a common procedure in patients with cranial defects secondary to trauma, infection, or tumor. The limitations of this technique include poor adherence of the acrylic to surrounding bone and difficulty in achieving a proper cosmetic contour in complicated cranial defects, especially those involving the orbital rim. The authors have been continually developing techniques of cranioplasty. METHODS: Ten consecutive cranioplasties were performed over the past 5 years using this new technique. TECHNIQUE: The authors describe a technique using miniplates as struts to which the acrylic is applied using a "reinforced concrete" principle. RESULTS/CONCLUSION: All patients achieved excellent cosmetic results with no complications. This technique allows contour of the repair site while the acrylic is curing and provides a more resilient resulting prosthesis.