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Spinal arteriovenous fistulas (AVFs) account for approximately 70% of all vascular spinal malformations and commonly develop in the lateral epidural space at the epidural /radicular venous junction. The fistula is located close to the spinal nerve root where a radiculomeningeal artery shunts to a radicular vein. Increased venous pressure leads to decreased spinal venous drainage and venous congestion causing progressive myelopathy, bowel/bladder incontinence and erectile dysfunction. Treatment consists of surgical occlusion of the intradural vein, or endovascular embolization, which has a reported success rate of 25%-75%. 1 Endovascular failure can occur with inadequate embolic penetration of the nidus and the proximal segment of the draining vein, or premature reflux of the liquid embolic agent.The use of a dual-lumen balloon microcatheter offers advantage in these cases given the ability to push liquid embolysate more distally during balloon inflation. The Scepter Mini is a new dimethyl-sulfoxide (DMSO)-compatible dual-lumen balloon microcatheter with a distal-tip outer diameter of 1.6 Fr and a nominal balloon diameter of 2.2 mm, facilitating atraumatic navigation and safer balloon inflation. Limited neurointerventional experience using the Scepter Mini in predominantly cerebrovascular cases has reported favorable navigability and flow arrest 2, 3 Although Onyx is rarely used for spinal AVF embolization, success has been reported considering the well-known favorable experience in cerebral cases. 1, 4, 5 We present one of the first cases of Onyx embolization of a spinal dural AVF through a Scepter Mini in a patient with progressively worsening lower extremity sensorimotor dysfunction. Operators should be aware of radiculomedullary arteries arising at the same level or at adjacent levels to avoid unintentional Onyx migration during balloon inflation., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Stereotactic radiosurgery (SRS) following surgical resection is the standard of care for patients with symptomatic oligo brain metastasis (BM), however, it is associated with 10-15% local failure. Targeting a resection cavity is imprecise, thus preoperative radiosurgery where the target is well-defined may be superior, however, the efficacy of preoperative SRS has not yet been tested in a clinical trial., Methods: We conducted a phase 2, single-arm trial of preoperative SRS followed by surgical resection in patients with 1-4 symptomatic oligo BMs (NCT03398694) with the primary objective of measuring 6-month local control (LC). SRS was delivered to all patients utilizing a gamma knife or linear accelerator as per RTOG-9005 dosing criteria [Shaw E, Scott C, Souhami L, et al. Single dose radiosurgical treatment of recurrent previously irradiated primary brain tumors and brain metastases: final report of RTOG protocol 90-05. Int J Radiat Oncol Biol Phys . 2000;47(2):291-298] based on tumor diameter with the exception that the largest lesion diameter treated was 5 cm with 15 Gy with all SRS treatment given in single fraction dosing., Results: The trial screened 50 patients, 48 patients were treated under the protocol and 32 patients completed the entire follow-up period. Of all the patients who completed the follow-up period, the primary endpoint of 6-month LC was 100% (95% CI: 0.891-1.000; P  = .005). Secondary endpoints, presented as medians, were overall survival (17.6 months), progression-free survival (5.3 months), distant in-brain failure (40.8% at 1 year), leptomeningeal failure (4.8% at 1 year), and radiation necrosis (7.7% at 1 year)., Conclusions: Our data confirms superior local control in patients who received preoperative SRS when compared to historical controls. Further study with a larger randomized cohort of patients is warranted to fully understand the benefits of preoperative SRS., Competing Interests: The authors declare no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Society for Neuro-Oncology and the European Association of Neuro-Oncology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Stereotactic radiosurgery (SRS) has been shown to be efficacious for the treatment of limited brain metastasis (BM); however, the effects of SRS on human brain metastases have yet to be studied. We performed genomic analysis on resected brain metastases from patients whose resected lesion was previously treated with SRS. Our analyses demonstrated for the first time that patients possess a distinct genomic signature based on type of treatment failure including local failure, leptomeningeal spread, and radio-necrosis. Examination of the center and peripheral edge of the tumors treated with SRS indicated differential DNA damage distribution and an enrichment for tumor suppressor mutations and DNA damage repair pathways along the peripheral edge. Furthermore, the two clinical modalities used to deliver SRS, LINAC and GK, demonstrated differential effects on the tumor landscape even between controlled primary sites. Our study provides, in human, biological evidence of differential effects of SRS across BM's., Competing Interests: The authors declare no competing interests., (© 2024 The Author(s).)

Epistaxis is common, impacting more than half the population, and can require procedural intervention in approximately 10% of cases. With an aging population and increasing use of antiplatelets and anticoagulants, severe epistaxis is likely to increase in frequency significantly over the next two decades. Sphenopalatine artery embolization is rapidly becoming the most common type of procedural intervention. The efficacy of endovascular embolization is dependent on a refined understanding of the anatomy and collateral physiology of this circulation as well as the impact of temporizing measures such as nasal packing and inflation of a nasal balloon. Likewise, safety is dependent on a detailed appreciation of collateralization with the internal carotid artery and ophthalmic artery. Cone beam CT imaging has the resolution to enable a clear visualization of the anatomy and collateral circulation associated with the arterial supply to the nasal cavity, in addition to assisting with hemorrhage localization. We present a review of epistaxis treatment, a detailed description of anatomic and physiologic considerations informed by cone beam CT imaging, and a proposed protocol for sphenopalatine embolization for which there is currently no standard., Competing Interests: Competing interests: DHS: grant from Microvention, consulting fees from Medtronic, Microvention and Phonex, support for attending meetings from Medtronic and Microvention, payment or honoraria for lectures from Medtronic and Microvention, equity from Scientia and Vasorum. AD: payment or honoraria from Cerenovus, payment for expert testimony. KA: consulting fees from Medtronic. TP: royalties from Stryker, payment for expert testimony. ER: consulting fees from Balt, Imperative Care and Medtronic, payment or honoraria for lectures from Penumbra, Medtronic, Stryker, Rapid Medical, Micrvention and Phenox, stock with Siemens, equity from Siemens, proctor for Microvention, site PI for PROST, Inspire and NECC. DG: consulting fees from iSchemaView, participation in RAPID AI Advisory Board, Chair of Stroke Performance Measures Oversight Committee (Stroke Council/American Heart Association)., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Cerebral aneurysm rupture is associated with high rates of morbidity and mortality. Detecting aneurysms at high risk of rupture is critical in management decision making. Rupture risk has traditionally been associated with size-measured as a maximum dimension. However, aneurysms are morphologically dynamic, a characteristic ignored by large prospective aneurysm risk studies. Manual measurement is challenging and fraught with error. We used an artificial intelligence (AI) measurement tool to study aneurysms that ruptured during conservative management to detect changes in size not appreciated by manual linear measurement., Methods: A single practice database with >5000 aneurysms was queried. Patients followed conservatively for an unruptured aneurysm were identified using appropriate diagnosis codes. This cohort was screened for subsequent rupture using procedure codes. Only patients with two vascular imaging studies before rupture were included., Results: Five patients met the criteria. All patients had aneurysm enlargement, two of which were not detected from manual linear measurements, including adjudication and analysis, during a multidisciplinary neurovascular conference in a high volume practice. Maximum dimension increased at a minimum of 1.8% (range 1.8-63.3%) from the first scan to the last, and aneurysm volume increased at a minimum of 5.9% (5.9-385.5%), highlighting the importance of volumetric measurement., Conclusions: AI-enabled volumetric measurements are more sensitive to changes in size and detected enlargement in all aneurysms that ruptured during conservative management. This finding has major implications for clinical practice and methods used for interval aneurysm measurement in patients being conservatively followed., Competing Interests: Competing interests: DHS: consultant for Medtronic, Microvention and Phenox, grant from Microvention, payment or honoraria for lectures from Medtronic and Microvention, support for attending meetings from Microvention and Medtronic. DPG: data support and consultant for iSchemaView. KA: consultant for Medtronic., (© Author(s) (or their employer(s)) 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Internal carotid artery (ICA) injuries represent a rare, potentially fatal complication of endoscopic endonasal skull base surgery (EESBS). The use of adenosine to induce transient hypotension and facilitate management of high-flow, high-pressure arterial lesions has been well-documented in neuro-endovascular literature. A similar setting in which adenosine-induced hypotension may prove beneficial is during the management of major vascular injury encountered during EESBS., Methods: A case of ICA injury and subsequent repair during EESBS is presented., Results: A 74-year-old female underwent endoscopic transsphenoidal resection for a recurrent pituitary adenoma. During suprasellar resection, the right cavernous ICA was inadvertently injured resulting in brisk bleeding. Immediate vascular tamponade was applied, and a crushed muscle graft was obtained. Two intravenous doses of adenosine were administered in quick succession to produce transient hypotension and facilitate repair of the injury with the graft. Neurovascular imaging revealed a small pseudoaneurysm which remained stable throughout the postoperative course. The patient underwent definitive stent embolization of the pseudoaneurysm 1 month following discharge., Conclusion: Prompt repair of ICA injury during EESBS is crucial, but often limited by poor visualization. Adenosine-induced hypotension has demonstrated great efficacy as an adjuvant in neurovascular clipping of intracranial aneurysms and remains a valuable tool for the endoscopic skull-base surgeon as well. In cases with high risk for ICA injury, adenosine should be readily available.

Background and Purpose: Acute ischemic stroke due to tandem occlusive lesions involves high-grade ICA stenosis or occlusion with a distal intracranial occlusion. Several approaches and devices exist in the treatment of tandem occlusions; however, a consensus on the optimal technique does not exist. The Dotter technique is a method of catheter-based angioplasty to recanalize cervical ICA occlusions. We present a modified dilator-Dotter technique, which involves a polyethylene, tapered inner dilator to initially cross the occlusion, followed by guide catheterization and subsequent intracranial thrombectomy. The purpose of this study was to examine the safety and efficacy of this dilator-Dotter technique., Materials and Methods: We performed a retrospective review of patients with acute stroke due to tandem ICA intracranial occlusions, treated with our dilator-Dotter technique and thrombectomy between June 2018 and December 2019. We examined clinical, radiographic, and procedural data, as well as complications and outcomes., Results: Thirty-two patients were included. In 100% of cases, the dilator-Dotter technique resulted in ICA recanalization allowing successful thrombectomy. TICI 2b-3 revascularization was obtained in 31 patients (96%), within an average time of 25 minutes. The average preprocedural ICA stenosis was 98%, including 23 patients (72%) with complete occlusion. Following the dilator-Dotter technique, average ICA stenosis improved to 59%. There were no instances of death, iatrogenic dissection, emboli to new territory, or symptomatic intracranial hemorrhage., Conclusions: The dilator-Dotter technique may be a safe and effective modification of the traditional Dotter technique in allowing rapid ICA recanalization in cases of acute ischemic stroke due to tandem occlusions., (© 2020 by American Journal of Neuroradiology.)

Background: Stereotactic radiosurgery (SRS) has emerged as a common adjuvant modality used with surgery for resectable brain metastases (BMs). However, the optimal sequence of the multi-modality therapy has not been established. The goal of the study is to evaluate 6-month local control utilizing pre-operative SRS followed by surgical resection for patients with 1-4 brain metastases., Methods: This prospective, single arm, phase II trial will recruit patients with up to 4 brain metastases and at least one resectable lesion. All lesions will be treated with SRS and symptomatic lesions will be resected within 1-4 days after SRS. Patients will be monitored for 6-month local control, in-brain progression free survival, distant in-brain failure, rate of leptomeningeal spread, radiation necrosis and overall survival. Additionally, we will also perform correlative radiobiological molecular studies to assess the effect of radiation dosing on the tumor tissue and clinical outcomes. We expect that pre-operative SRS to the gross tumor prior to surgical resection will improve local control and decrease leptomeningeal failure., Discussion: Our study is the second prospective trial to investigate the efficacy of pre-operative SRS in the treatment of multiple BMs. In addition, the correlative molecular studies will be the first to investigate early response of BMs at a cellular and genetic level in response to radiation doses and potentially provide molecular prognostic markers for local control and overall survival., Trial Registration: Clinicaltrials.gov identifier: NCT03398694 (registration date: January 12, 2018).

Background: Although gun-related penetrating traumatic brain injuries make up the majority of cranial missile injuries, low-velocity penetrating injuries present significant clinical difficulties that cannot necessarily be identically managed. Bow hunting is an increasingly popular pastime, and a crossbow allows a unique mechanism to cause a self-inflicted cranial injury with a large, low-velocity projectile. Historically, arrow removal is described in an operating room setting, which provides limited knowledge of the location of vascular injury in the setting of postremoval hemorrhage, and may represent an inefficient use of operating room availability., Case Description: Two patients presented after self-inflicted cranial crossbow injuries. Both were neurologically salvageable. Initial assessment with computed tomography angiography allowed triage into likely or unlikely vascular injury. Arrow removal was performed in a radiology setting rather than in the operating room to allow immediate postremoval imaging to localize hemorrhage. While an operating room was on standby, neither patient required neurosurgical operative intervention. Both patients made a good recovery with no further injury caused by arrow removal., Conclusions: We describe a novel approach to retained cranial arrow removal in a radiologic, rather than operative, setting and describe its relative benefits over traditional removal in the operating room., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVE Most patients suffering from aneurysmal subarachnoid hemorrhage (aSAH) initially present to a hospital that lacks a neurosurgical unit. These patients require interhospital transfer (IHT) to tertiary facilities capable of multidisciplinary neurosurgical intervention. Yet, little is known about the effects of IHT on the outcomes of patients suffering from aSAH. In this study, the authors examined the effects of IHT and transport method on the timing of treatment, rebleed rates, and overall outcomes of patients who have experienced aSAH. METHODS A retrospective review of medical records identified all consecutive patients who presented with aSAH at an outside hospital and subsequently underwent IHT to a tertiary aneurysm care center and patients who initially presented directly to a tertiary aneurysm care facility between 2008 and 2015. Demographic, operative, radiological, hospital of initial evaluation, transfer method, and outcome data were retrospectively collected. RESULTS The authors identified 763 consecutive patients who were evaluated for aSAH at a tertiary aneurysm care facility either directly or following IHT. For patients who underwent IHT and after accounting for these patients' clinical variability and dichotomizing the patients into groups transferred less than 20 miles and more than 20 miles, the authors noted a significant increase in mortality rates: 7% (< 20 miles) and 18.8% (> 20 miles) (p = 0.004). The increased mortality rate was partially explained by an increased rate of initial presentation to an accredited stroke center in patients undergoing IHT of less than 20 miles (p = 0.000). The method of transport (ground or air ambulance) was found to have significant effect on the patients' outcomes as measured by the Glasgow Outcome Scale score (p = 0.021); patients who underwent ground transport demonstrated a higher likelihood of discharge to home (p = 0.004). The increased severity of presentation in the patient cohort undergoing IHT by air as defined by the Glasgow Coma Scale score, a need for an external ventricular drain, Hunt and Hess grade, and intubation status at presentation did not result in increased mortality when compared with the ground cohort (p = 0.074). In addition, there was an 8-hour increase in duration of time from admission to treatment for the air cohort as compared with the ground cohort (p = 0.054), indicating a potential for further improvement in the overall outcome of this patient group. CONCLUSIONS Aneurysmal SAH remains a challenging neurosurgical disease process requiring highly coordinated care in tertiary referral centers. In this study, the overall distance traveled and the transport method affected patient outcomes. The time from admission to treatment should continue to improve. Further analysis of IHT with a focus on patient monitoring and treatment during transport is warranted.

Background and Importance: Indocyanine green angiography (ICGA) has become a useful intraoperative tool during aneurysm surgery to determine parent, branching, and perforator vessel patency. Although extremely useful, ICGA is limited to the evaluation of vessels that are in direct view in the surgical field., Clinical Presentation: We present 2 cases of patients who underwent a craniotomy for clipping of unruptured posterior communicating artery aneurysms. A Yaşargil movable mirror was used as an adjuvant to ICGA to visualize the ventromedial posterior communicating vessels after clip placement to determine vessel patency., Conclusion: Although ICGA can be very useful during aneurysm surgery, it is limited to vessels directly visualized in the surgical field. A Yaşargil movable mirror can be used during ICGA to visualize elusive vessels, in these cases on the ventromedial surface of the internal carotid artery.

Background: Telemedicine has emerged as an efficient means of distributing professional medical expertise over a broad geographic area with few limitations to the various services that can be provided around the globe. Telepathology is particularly well suited to distributing subspecialty expertise in certain environments in an economical fashion, while preserving centers of excellence., Materials and Methods: After a decade of intrainstitutional teleneuropathology for intraoperative consultation, we expanded our practice to cross state lines and communicate between geographically and financially separate medical centers., Results: The result was an effective means of distributing neuropathological expertise while at the same time preserving a professional center of excellence. While technical and legal (i.e., physician licensing) barriers were surmounted, expected and unexpected issues related to communication required commitment on the part of multiple individuals with diverse expertise and responsibilities., Conclusion: Lessons learned from this successful venture can be used to facilitate future efforts in this ever-growing practical vehicle for distributing pathology subspecialty expertise.

Background: The adequate repair of intraoperative CSF leaks during transsphenoidal surgery remains a challenge. The authors describe the application of N-butyl 2-cyanoacrylate (cyanoacrylate) tissue glue for repair of CSF fistulas during transsphenoidal surgery., Methods: The authors retrospectively reviewed the records of 221 consecutive patients who underwent transsphenoidal surgery during 1998-2007. Among these patients, 52 (24%) experienced detectable intraoperative CSF leakage. The CSF fistulas were graded on a scale of 1-3, according to the amount of CSF loss and extent of diaphragmatic disruption. 39 patients who had an average leak scale of 1.28 received cyanoacrylate glue to seal the floor. The remaining 13 patients who were not part of this report received other dura sealant substitutes, including Tisseel and Dura Seal, or fat/cartilage grafts without any additional glue material., Results: 4 of 221 patients (2%) who underwent surgery had postoperative CSF fistula. Of the 39 patients who underwent repair of their fistula using fat graft, cartilage/bone buttress and cyanoacrylate reconstruction, 2 (5.13%) developed postoperative CSF fistulas without any other side effects. The average intraoperative leak grade in these 2 patients was 2.00., Conclusions: The authors used cyanoacrylate glue for intraoperative repair of higher grade CSF fistulas. As an adjunct to careful sellar reconstruction, cyanoacrylate glue appears to be effective and safe in preventing postoperative CSF leakage after transsphenoidal surgery., (© Georg Thieme Verlag KG Stuttgart · New York.)

Object: The authors prospectively evaluated the safety and efficacy of a novel polyethylene glycol (PEG) hydrogel sealant in patients undergoing elective cranial surgery with documented cerebrospinal fluid (CSF) leakage after sutured dural repair., Methods: The PEG hydrogel sealant was used at 11 different study sites in 111 patients with documented intraoperative CSF leakage after neurosurgical dural repair for a variety of conditions. Intraoperative CSF leakage was either spontaneous or induced by a Valsalva maneuver. Patients were monitored for 3 months postoperatively with physical examinations, clinical laboratory analyses, and diagnostic imaging. The PEG hydrogel sealant was 100% effective in stopping CSF leakage in all patients. There were no sealant-related adverse events and all clinical outcomes were consistent with expectations for seriously ill patients undergoing prolonged neurosurgical procedures., Conclusions: The PEG hydrogel sealant provides a safe and effective watertight closure when used as an adjunct to sutured dural repair during cranial surgery.

Dysregulation of enzymes involved in prostaglandin biosynthesis plays a critical role in influencing the biological behavior and clinical outcome of several tumors. In human gliomas, overexpression of cyclooxygenase-2 has been linked to increased aggressiveness and poor prognosis. In contrast, the role of prostaglandin E synthase in influencing the biological behavior of human gliomas has not been established. We report that constitutive expression of the microsomal prostaglandin E synthase-1 (mPGES-1) is associated with increased prostaglandin E(2) (PGE(2)) production and stimulation of growth in the human astroglioma cell line U87-MG compared with human primary astrocytes. Consistently, pharmacologic and genetic inhibition of mPGES-1 activity and expression blocked the release of PGE(2) from U87-MG cells and decreased their proliferation. Conversely, exogenous PGE(2) partially overcame the antiproliferative effects of mPGES-1 inhibition and stimulated U87-MG cell proliferation in the absence of mPGES-1 inhibitors. The EP2/EP4 subtype PGE(2) receptors, which are linked to stimulation of adenylate cyclase, were expressed in U87-MG cells to a greater extent than in human astrocytes. PGE(2) increased cyclic AMP levels and stimulated protein kinase A (PKA) activity in U87-MG cells. Treatment with a selective type II PKA inhibitor decreased PGE(2)-induced U87-MG cell proliferation, whereas a selective type I PKA inhibitor had no effect. Taken together, these results are consistent with the hypothesis that mPGES-1 plays a critical role in promoting astroglioma cell growth via PGE(2)-dependent activation of type II PKA.

Objective: Intraoperative rupture (IOR) of an aneurysm is a known risk in the surgical management of intracranial aneurysms. The purpose of this study was to determine the incidence of IOR in a modern surgical series and to assess which factors bear upon it., Methods: This study retrospectively examined 1269 patients with saccular aneurysms treated surgically between 1986 and 1998. Three vascular neurosurgeons performed 1435 operations on 1694 aneurysms. Multiple factors, including the magnitude and time of occurrence of IOR, aneurysm location, subarachnoid hemorrhage, timing of surgery, and use of temporary occlusion, were analyzed., Results: There were 113 instances of IOR (7.9% per surgery; 6.7% per aneurysm; 8.9% per patient). If the 59 "minor leaks" are excluded (as in previously published reports), the incidence becomes 3.8% per surgery, 3.2% per aneurysm, and 4.3% per patient. Posteroinferior cerebellar artery and anterior and posterior communicating artery aneurysms were more liable to rupture intraoperatively. The IOR rate was greater in ruptured than unruptured aneurysms (10.7 versus 1.2%, P < 0.0001). There was a lower rate of IOR in operations using temporary arterial occlusion (3.1 versus 8.6%, P < 0.0001). The occurrence of IOR for early surgery was not significantly higher than for surgery performed more than 3 days after subarachnoid hemorrhage (11.1 versus 10.0%, P = 0.6234)., Conclusion: The rate of significant IOR can be kept low. Aneurysm location, subarachnoid hemorrhage, and temporary arterial occlusion seem to be important factors affecting the incidence of IOR.

Neuromuscular choristoma (NMC) is an uncommon tumor that usually involves a large nerve trunk. Only 28 cases of NMC have been previously reported in the English-language literature, 17 of which involved cranial nerves. We report a new case of intracranial NMC that arose from a facial nerve at the cerebellopontine angle in a 44-year-old man. The patient was taken to surgery, where the lesion was found to involve the right facial nerve. The tumor was partially removed, and at the 2-year follow-up, the patient showed no sign of recurrence.

Unlabelled: The benefit of using intraoperative angiography (IA) during aneurysm surgery is still uncertain., Object: In this prospective study, the authors evaluate the radiographically demonstrated success of surgical treatment in 151 consecutive patients harboring 173 aneurysms who selectively underwent IA examination. The authors also assess the frequency with which IA led to repositioning of the aneurysm clip., Methods: Intraoperative angiography was used selectively in this series, based on the surgeon's concern about the potential for residual aneurysm, distal branch occlusion, or parent vessel stenosis. Specific variables were analyzed to determine their impact on the incidence of clip repositioning and the accuracy of IA was evaluated by direct comparison with postoperative angiography (PA) in 90% of the cases in which IA was used., Conclusions: The selective use of IA led to successful treatment as shown by PA, with a low incidence of unexpected residual aneurysm (3.2%), distal branch occlusion (1.9%), and parent vessel stenosis (0%). Intraoperative angiography led to immediate repositioning of the aneurysm clip in 27% of the cases. Anterior cerebral artery aneurysms required clip repositioning less often and superior hypophyseal artery aneurysms required repositioning more often than aneurysms in other locations. Large and giant aneurysms required clip repositioning more often than small aneurysms; however, they were also more likely to display false success on IA as determined by PA. Aneurysms arising along the internal carotid artery were more likely to display successful clipping on IA, as determined by PA, than were aneurysms in other locations. The results of this series support the selective use of IA in the treatment of complex aneurysms, particularly large and giant aneurysms as well as superior hypophyseal artery aneurysms. As measured by PA, IA will improve the outcome of these patients.

The success of medical and surgical treatment for hemifacial spasm, and involuntary paroxysmal unilateral contraction of the facial muscles, has been mixed. Although microvascular decompression has the greatest reported success, symptom recurrence affects many patients in whom treatment was initially successful. In this study, we report the results of 34 patients who underwent microvascular decompression of the facial nerve from 1976 to 1989 as well as review the literature concerning the incidence and timing of recurrence in more than 600 patients who underwent microvascular decompression. In this series, 94% of 34 patients had continuous relief of spasm after surgical treatment (mean duration, > 6 yr). Of those patients whose spasms were completely initially relieved, 10.3% developed some degree of recurrent spasm; however, no patient developed a recurrence after 24 months without spasm. Our review of the literature discloses that 86% of all recurrences occurred within 2 years of surgery. Patients who have no recurrence of symptoms 2 years after surgical treatment have only a 1% chance of developing recurrent hemifacial spasm. We also comment on possible causes of treatment failure and recurrence of hemifacial spasm after surgical treatment.

Intracranial section of the glossopharyngeal and upper vagal rootlets for the treatment of vagoglossopharyngeal neuralgia may cause dysphagia or vocal cord paralysis from injury to the motor vagal rootlets in 10% to 20% of cases. To minimize this complication, we recently applied a technique of intraoperative monitoring of the vagus nerve (previously described by Lipton and McCaffery to monitor the recurrent laryngeal nerve during thyroid surgery) in a patient undergoing intracranial rhizotomy for vagoglossopharyngeal neuralgia. By inserting an electrode in the ipsilateral false vocal cord and stimulating the rostral vagal rootlets intraoperatively under general anesthesia, we could differentiate the rostral vagal motor rootlets from the sensory rootlets. In this patient, the technique allowed us to preserve a rostral vagal rootlet, which if sectioned, could have caused dysphagia or vocal cord paralysis. We conclude that intraoperative monitoring of the rostral vagal rootlets is an important technique to minimize complications of upper vagal rhizotomy.

Cavernous angiomas of the dura mater are clinically and radiographically distinct from parenchymal cavernous angiomas. In this report, we present two cases of dural cavernous angiomas located outside the middle cranial fossa. The first patient is a 36-year-old woman with two dural cavernous angiomas, including one that enlarged during a 2-year period of observation. The second patient is a 33-year-old man with medically intractable seizures from a dural cavernous angioma of the convexity, which was discovered at autopsy. From our experience and a review of the literature, we have identified two groups of dural cavernous angiomas that differ in incidence, natural history, and surgical management. Most dural cavernous angiomas arise from the middle fossa; in contrast, only 15 cases of dural cavernous angiomas outside the middle fossa have been reported. Those in the middle fossa are more clinically aggressive and more difficult to resect surgically, because they grow toward the cavernous sinus and the parasellar region. Most patients with dural cavernous angiomas outside the middle fossa present with headaches, whereas those patients with dural cavernous angiomas in the middle fossa present with ocular signs, visual field defects, endocrinopathy, and trigeminal symptoms. Radiographically, both of the angiomas resemble meningiomas. Because of their intimate association with the cavernous sinus, surgical resection of middle fossa cavernous angiomas often is incomplete and may require postoperative radiosurgery to control growth. In contrast, angiomas in other locations are easily and successfully resected with little blood loss. The location of dural cavernous angiomas is an important factor in making the surgical decision and in predicting the outcome.

The acquired descent of the cerebellar tonsils radiographically indistinguishable from Chiari I malformations has been previously reported. The relationship between lumbar shunting procedures for hydrocephalus and symptomatic Chiari malformations has been established. We report the cases of 10 children with lumboperitoneal shunts in whom previous radiographic studies had confirmed a normal hindbrain configuration. Seven of the 10 patients acquired tonsillar descent into the foramen magnum, detected by magnetic resonance imaging, whereas the others remained normal. Four of seven patients were symptomatic; two underwent the removal of the lumboperitoneal shunt and conversion to a ventriculoperitoneal shunt, and two underwent posterior fossa decompression. Further magnetic resonance imaging revealed that one of the two patients who underwent conversion shows ascent of the cerebellar tonsils. All four patients became asymptomatic less than 6 months after treatment. In this article, we discuss seven cases of acquired Chiari malformations and the complete reversal of an acquired Chiari malformation after surgical treatment, as documented by magnetic resonance imaging. Cases of asymptomatic acquired Chiari malformations are reported, including those resulting from shunting for intracranial hypertension without hydrocephalus. We conclude that a craniospinal pressure gradient creates a potential for cerebellar tonsil descent and recommend that ventriculoperitoneal shunting be performed in children with communicating hydrocephalus to avoid this potential complication. We also recommend annual surveillance of the cervicomedullary junction in children with lumboperitoneal shunting. Finally, if symptomatic tonsillar descent occurs from lumbar shunting, a trial conversion to ventriculoperitoneal shunting may eliminate the need for posterior fossa decompression.

Sucrose density centrifugation has been used to characterize the relative levels of AChE molecular forms in different parts of the brain, during development, or in various disease states. We have examined the influence of various tissue or sample storage and handling techniques on the abundance of the 4S and 10S molecular forms of AChE in rat forebrain. Our results demonstrate that freezing either a subcellular fraction or the intact tissue causes dramatic shifts in the level of the 4S and 10S molecular forms as compared to the values obtained in fresh tissue. Total AChE activity was unchanged suggesting that 4S and 10S forms are equally active and that 4S AChE is easily dissociated from 10S. These observations suggest that 4S and 10S molecular forms in brain are extremely labile and that great care should be taken when studying the factors that regulate these forms.