Microsurgical Resection of a Large Intraventricular Trigonal Tumor: 3-Dimensional Operative Video

A 62-yr-old woman presented with incidentally detected left trigonal mass by magnetic resonance imaging (MRI) performed during workup for left-sided hearing loss and vertigo of 5-yr duration. Due to persistent dizziness, headache, and progressive enlargement of the tumor in follow-up scans, operation was planned. Because the tumor extended superiorly, a superior parietal lobule approach was selected.She underwent a left parietal craniotomy. A strip electrode was used to localize the motor and sensory regions, and neuronavigation was used to confirm the entry site. A small transsulcal corticotomy was performed posterior to a large cortical vein. The tumor was pinkish in color with a well-defined capsule. It was centrally debulked by using curettes, pituitary forceps, and the ultrasonic aspirator. Tumoral blood supply from the choroid plexus and the posterior choroidal vessels were cauterized and divided. Additional blood supply coming from the anterior choroidal vessels was also found and cauterized. After circumferential dissection of the tumor capsule, the tumor was removed completely. The pathology indicated WHO Grade I meningioma. The patient had mild expressive and receptive aphasia postoperatively, but improved progressively. The postoperative MRI showed total resection with no evidence of brain injury. At 3-mo follow-up, the speech was normal; she was independent for all daily activities, but had not yet returned to work (Karnofsky score 80).This 3-D video shows the technical nuances of microsurgical resection of an intraventricular tumor through a narrow brain corridor.Informed consent was obtained from the patient prior to the surgery that included videotaping of the procedure and its distribution for educational purposes. All relevant patient identifiers have also been removed from the video and accompanying radiology slides.

Semi-autonomous image-guided brain tumour resection using an integrated robotic system: A bench-top study

BACKGROUND

Complete brain tumour resection is an extremely critical factor for patients' survival rate and long-term quality of life. This paper introduces a prototype medical robotic system that aims to automatically detect and clean up brain tumour residues after the removal of tumour bulk through conventional surgery.

METHODS

We focus on the development of an integrated surgical robotic system for image-guided robotic brain surgery. The Behavior Tree framework is explored to coordinate cross-platform medical subtasks.

RESULTS

The integrated system was tested on a simulated laboratory platform. Results and performance indicate the feasibility of supervised semi-automation for residual brain tumour ablation in a simulated surgical cavity with sub-millimetre accuracy. The modularity in the control architecture allows straightforward integration of further medical devices.

CONCLUSIONS

This work presents a semi-automated laboratory setup, simulating an intraoperative robotic neurosurgical procedure with real-time endoscopic image guidance and provides a foundation for the future transition from engineering approaches to clinical application.

Transpetrosal approach to petro-clival meningioma

A 38-year-old woman had a 3-week gradual onset of right-sided weakness in the upper and lower extremities. MRI showed a large left petro-clival meningioma encasing the basilar and left superior cerebellar artery and compressing the brainstem. A posterior transpetrosal approach, with a left temporal and retrosigmoid craniotomy and mastoidectomy, was performed. The tumor was removed in a gross-total resection with questionable remnants adherent to the brainstem. Intraoperative partial iatrogenic injury to the left oculomotor nerve was repaired with fibrin glue. Postoperatively, the hemiparesis improved, and the patient was discharged to the rehabilitation center with left oculomotor and abducens palsies. A postoperative MRI scan showed complete resection of tumor with no remnants on the brainstem. A 6-month follow-up examination showed complete resolution of motor symptoms and complete recovery of cranial nerve (CN) palsies affecting CN III and CN VI. The video can be found here: https://youtu.be/vOu6YFA8uoo .

Onyx embolization prior to stereotactic radiosurgery for brain arteriovenous malformations: a single-center treatment algorithm

BACKGROUND

Embolization before stereotactic radiosurgery (SRS) for brain arteriovenous malformations (BAVMs) is controversial.

OBJECTIVE

To compare clinical and radiographic outcomes in patients undergoing pre-SRS embolization with ethylene copolymer (Onyx) with outcomes in patients undergoing SRS alone.

METHODS

Seventy consecutive patients with BAVMs who underwent SRS were retrospectively reviewed. Univariate and multivariate analyses were performed to assess the factors associated with radiographic obliteration and complication.

RESULTS

Forty-one (59%) patients presented without BAVM rupture and 29 (41%) patients presented with rupture. Pre-SRS embolization was used in 20 patients (28.6%; 7 unruptured and 13 ruptured). Twenty-five of 70 (36%) patients sustained a complication from treatment, including 6 (9%) patients with a post-SRS latency period hemorrhage. Ten (14%) patients had persistent neurological deficits after treatment. Functional outcome (as modified Rankin Scale), complication rate, and radiographic obliteration at last follow-up were not significantly different between embolized and non-embolized groups in both unruptured and ruptured BAVMs. For unruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 23% and 73% for non-embolized patients and 20% and 60% for embolized patients, respectively. For ruptured BAVMs, 3- and 5-year rates of radiographic obliteration were 45% and 72% for non-embolized patients and 53% and 82% for embolized patients, respectively.

CONCLUSION

Pre-SRS embolization with Onyx was not associated with worse clinical or radiographic outcomes than SRS treatment without embolization. Pre-SRS embolization has a low complication rate and can safely be used to target high-risk BAVM features in carefully selected patients destined for SRS.

Basilar Artery Ectasia Causing Trigeminal Neuralgia: An Evolved Technique of Transpositional Suture-Pexy

BACKGROUND

Microvascular decompression for patients with trigeminal neuralgia (TGN) is widely accepted as one of the modalities of treatment. The standard approach has been retrosigmoid suboccipital craniotomy with placement of a Teflon pledget to cushion the trigeminal nerve from the offending artery, or cauterize and divide the offending vein(s). However, in cases of severe compression caused by a large artery, the standard decompression technique may not be effective.

OBJECTIVE

To describe a unique technique of vasculopexy of the ectatic basilar artery to the tentorium in a patient with TGN attributed to a severely ectatic and tortuous basilar artery. A case series of patients who underwent this technique of vasculopexy for arterial compression is presented.

METHODS

The patient underwent a subtemporal transtentorial approach and the basilar artery was mobilized away from the trigeminal nerve. A suture was then passed through the wall of the basilar artery (tunica media) and secured to the tentorial edge, to keep the artery away from the nerve.

RESULTS

The neuralgia was promptly relieved after the operation, with no complications. A postoperative magnetic resonance imaging scan showed the basilar artery to be away from the trigeminal root. In a series of 7 patients who underwent this technique of vasculopexy, no arterial complications were noted at short- or long-term follow-up.

CONCLUSION

Repositioning and vasculopexy of an ectatic basilar artery for the treatment of TGN is safe and effective. This technique can also be used for other neuropathies that result from direct arterial compression.

Cerebral Revascularization for Aneurysms in the Flow-Diverter Era

BACKGROUND: Cerebral bypass has been an important tool in the treatment of complex intracranial aneurysms. The recent advent of flow-diverting stents (FDS) has expanded the capacity for endovascular arterial reconstruction.

OBJECTIVE: We investigated how the advent of FDS has impacted the application and outcomes of cerebral bypass in the treatment of intracranial aneurysms.

METHODS: We reviewed a consecutive series of cerebral bypasses during aneurysm surgery over the course of 10 years. FDS were in active use during the last 5 years of this series. We compared the clinical characteristics, surgical technique, and outcomes of patients who required cerebral bypass for aneurysm treatment during the preflow diversion era (PreFD) with those of the postflow diversion era (PostFD).

RESULTS: We treated 1061 aneurysms in the PreFD era (from July 2005 through June 2010) and 1348 in the PostFD era (from July 2010 through June 2015). Eighty-five PreFD patients (8%) and 45 PostFD patients (3%) were treated with cerebral bypass. PreFD patients had better baseline functional status compared to PostFD patients with average preoperative modified Rankin Scale score of 0.55 in PreFD and 1.18 in PostFD.

CONCLUSION: After the introduction of FDS, cerebral bypass was performed in a lower proportion of patients with aneurysms. Patients selected for bypass in the flow-diverter era had worse preoperative modified Rankin Scale scores indicating a greater complexity of the patients. Cerebral bypass in well-selected patients and revascularization remains an important technique in vascular neurosurgery. It is also useful as a rescue technique after failed FDS treatment of aneurysms.

The dual microcatheter technique for transvenous embolization of dural arteriovenous fistulae

Background

Dural arteriovenous fistulae (dAVFs) comprise 10–15% of all intracranial arteriovenous malformations. The goal of surgical or endovascular intervention is complete obliteration of the fistulous connection(s). In cases where dAVF venous drainage is separate from normal cortical drainage, transvenous embolization can provide fast and effective fistula obliteration.

Objective

To describe a new method of efficient transvenous embolization (the ‘dual microcatheter technique’) for the treatment of dAVFs.

Methods

Three patients with dAVFs were treated using the dual microcatheter technique for transvenous embolization. Two microcatheters were placed in the distal aspect of the dAVF venous pouch, after which coil embolization reduced fistula flow, and liquid embolic agent injection with reflux into arterial feeders completed the obliteration of the fistula.

Results

Lesion grade ranged from Borden–Shucart grades 2 through 3. In all cases, dAVF venous drainage was isolated from the normal cerebral venous drainage. Dual microcatheter transvenous embolization was successful in all patients, with non-target embolization and no new postoperative deficits. At the last follow-up, all three patients were symptom-free without evidence of radiographic recurrence.

Conclusions

The dual microcatheter technique of transvenous dAVF embolization is safe and feasible in cases where dAVF venous outflow is isolated from normal cerebral venous drainage.

Toward a comprehensive assessment of functional outcomes in pediatric patients with brain arteriovenous malformations: the Pediatric Quality of Life Inventory

OBJECTIVE Brain arteriovenous malformations (bAVMs) are rare in pediatric patients but represent the most common cause of hemorrhagic stroke in this population. Pediatric patients demonstrate superior outcomes in comparison with adult patients with similar lesions and presentations. Most studies of clinical outcomes of pediatric bAVMs use the modified Rankin Scale (mRS), despite a lack of validation in pediatric patients. METHODS The authors interviewed the parents of 26 pediatric patients who underwent multimodality bAVM treatment and administered the Pediatric Quality of Life Inventory (PedsQL)-a well-validated tool for pediatric outcomes that quantifies performance in a physical, emotional, social, and school domains. They also reviewed clinical information from the patients' medical charts. Statistical analysis was performed using a log-transformed t-test, the Mann-Whitney exact test, the Kruskal-Wallis test, and Spearman correlation. In addition, the literature was reviewed for prior reports of clinical outcome of pediatric cases of bAVM. RESULTS The average PedsQL health-related quality of life score was 71 ± 24, with an average age at diagnosis of 12.5 years and an average follow-up period of 6.8 years. Seventeen patients (65%) presented with hemorrhage and 4 (15%) with seizures. PedsQL scores correlated strongly and at a statistically significant level (p < 0.001) with mRS, Pediatric Overall Performance Category (POPC), Pediatric Cerebral Performance Category (PCPC), and Glasgow Outcome Scale scores. Multivariate modeling validated special education, corrective devices, and cure status as significant predictors of PedsQL scores. Statistically significant risk factors for undergoing placement of a ventriculoperitoneal shunt included lower Glasgow Coma Scale motor scores on admission (p = 0.042), cerebellar location (p = 0.046), and nidus volume (p = 0.017). Neither treatment modality nor location statistically affected clinical outcomes at follow-up. CONCLUSIONS There have been few studies of long-term clinical outcomes of bAVM in pediatric patients, and previously published studies have used conventional metrics that have been validated in the adult population, such as the mRS. Although these metrics can serve as reasonable surrogates, an accurate understanding of overall health-related quality of life is contingent on utilizing validated toolsets, such as the PedsQL.

High-resolution intracranial vessel wall imaging: imaging beyond the lumen

Accurate and timely diagnosis of intracranial vasculopathies is important due to significant risk of morbidity with delayed and/or incorrect diagnosis both from the disease process as well as inappropriate therapies. Conventional vascular imaging techniques for analysis of intracranial vascular disease provide limited information since they only identify changes to the vessel lumen. New advanced MR intracranial vessel wall imaging (IVW) techniques can allow direct characterisation of the vessel wall. These techniques can advance diagnostic accuracy and may potentially improve patient outcomes by better guided treatment decisions in comparison to previously available invasive and non-invasive techniques. While neuroradiological expertise is invaluable in accurate examination interpretation, clinician familiarity with the application and findings of the various vasculopathies on IVW can help guide diagnostic and therapeutic decision-making. This review article provides a brief overview of the technical aspects of IVW and discusses the IVW findings of various intracranial vasculopathies, differentiating characteristics and indications for when this technique can be beneficial in patient management.

Safety and Efficacy of Preoperative Embolization of Intracranial Hemangioblastomas

BACKGROUND

Intracranial hemangioblastomas are highly vascular tumors that account for 1% to 2% of all central nervous system tumors. Preoperative embolization has been proposed to limit the often significant intraoperative blood loss associated with resection and potentially make the tumor more soft/necrotic and thus more amenable to gross total resection. The safety and efficacy of preoperative embolization of intracranial hemangioblastomas, however, are not well characterized.

OBJECTIVE

To evaluate the safety and efficacy of preoperative endovascular embolization of intracranial hemangioblastomas using a variety of embolic agents.

METHODS

A retrospective review of all surgically resected intracranial hemangioblastomas treated with preoperative embolization between 1999 and 2014 at 2 high-volume centers was performed. Clinical and radiographic criteria, including von Hippel-Lindau status, magnetic resonance imaging tumor characteristics, embolization-related complications, degree of angiographic devascularization, intraoperative blood loss, ability to obtain gross total resection, transfusion requirements, and operative time, were analyzed.

RESULTS

A total of 54 patients underwent surgery, with 24 undergoing preoperative embolization followed by surgical resection, and 30 patients undergoing surgical resection alone. Embolization-related neurological complications were seen in 6 patients (25%), including 3 hemorrhages when polyvinyl alcohol particles (P = .04) were used and 3 infarctions when liquid embolic agents were used (P = .27). Permanent neurological deficits were seen in 15%.

CONCLUSION

Preoperative embolization of intracranial hemangioblastomas should be performed with caution, given the potential for neurological morbidity. Further studies are needed to help guide patient and embolic agent selection.

Outcomes of Multimodality Therapy in Pediatric Patients With Ruptured and Unruptured Brain Arteriovenous Malformations

BACKGROUND:

Brain arteriovenous malformations (BAVMs) are a frequent cause of pediatric hemorrhagic stroke, which frequently results in significant morbidity and mortality.

OBJECTIVE:

To analyze the results of multimodality treatment for a consecutive series of pediatric patients with ruptured and unruptured BAVMs at a single institution.

METHODS:

Forty patients &lt;18 years of age were retrospectively reviewed. Results were divided by hemorrhage status, ie, ruptured or unruptured, and the intended curative treatment modality, ie, surgical resection or stereotactic radiosurgery.

RESULTS:

Twenty-seven patients (68%) presented with hemorrhage, and 13 patients (32%) presented without hemorrhage. Among ruptured patients, 19 (70%) underwent surgery and 8 (30%) underwent stereotactic radiosurgery. In surviving patients who presented with hemorrhage, 23 of 26 (88%) had a modified Rankin Scale (mRS) score of 0 to 2 at the last follow-up, and 24 of 26 (92%) obtained radiographic cure. For unruptured BAVMs, all 6 patients with grade I to III BAVM obtained radiographic cure and had an mRS score of 0 to 1 at the last follow-up, whereas 1 of 5 patients (20%) with grade IV and V BAVM had BAVM obliteration and a mean mRS score of 1.8 at the last follow-up. In a total of 93.6 years of follow-up from date of presentation to last clinical follow-up, there was 1 hemorrhage (1.1%/y). Of 30 patients with radiographic obliteration, 2 patients had radiographic recurrence (7% incidence).

CONCLUSION:

The majority of ruptured patients had an mRS score of 0 to 2 at the last follow-up and obtained radiographic cure. Unruptured patients with grade I to III BAVMs had superior outcomes compared with those with grade IV and V AVMs. Treatment of grade I to III BAVMs appears safe, and additional study is needed to determine optimal strategies for the management of unruptured grade IV and V BAVMs.

Bypasses and reconstruction for complex brain aneurysms

Microsurgery for brain aneurysms is a current relevant technique, as advances in endovascular and stent-assisted coiling have not solved many of the difficulties inherent in the management of complex brain aneurysms. The following review highlights the importance of microsurgical bypass techniques for the management of complex cerebrovascular aneurysms and emphasizes, through two clinical cases, the technical difficulties and indications for bypass surgery. These cases demonstrate that in selected scenarios, bypass microsurgery still offers the only viable treatment for complex aneurysms.

Laser-assisted flat-detector CT-guided intracranial access

PURPOSE

Flat-detector CT can be integrated with C-arm fluoroscopy for CT-guided neurosurgical and endovascular procedures. We studied the accuracy of this technique with laser assistance in targeting intracranial lesions in a cranial model.

METHODS

An acrylic scale-model skull containing foam parenchyma was embedded with 2.16-mm-diameter targets. A flat-detector CT was acquired and registered to the skull's position. Ten targets were accessed with biopsy needles under fluoroscopic guidance, flat-detector CT overlay, and laser assistance. Accuracy was measured from the needle tip to the target center using flat-detector CT.

RESULTS

Ten targets were accessed successfully using XperGuide software. Needles were placed within 1.30 [Formula: see text] 0.63 mm of target isocenter. Accuracy did not vary by entry site, operator, location, or lesion depth.

CONCLUSIONS

Laser-assisted flat-detector CT-guided targeting of all intracranial targets was successful with excellent accuracy. This technique can be applied to other minimally invasive neurosurgical procedures.

Treatment Outcomes of Unruptured Arteriovenous Malformations With a Subgroup Analysis of ARUBA (A Randomized Trial of Unruptured Brain Arteriovenous Malformations)-Eligible Patients

BACKGROUND:

The design and conclusions of A Randomized Trial of Unruptured Brain Arteriovenous Malformations (ARUBA) trial are controversial, and its structure limits analysis of patients who could potentially benefit from treatment.

OBJECTIVE:

To analyze the results of a consecutive series of patients with unruptured brain arteriovenous malformations (BAVMs), including a subgroup analysis of ARUBA-eligible patients.

METHODS:

One hundred five patients with unruptured BAVMs were treated over an 8-year period. From this series, 90 adult patients and a subgroup of 61 patients determined to be ARUBA eligible were retrospectively reviewed. A subgroup analysis for Spetzler-Martin grades I/II, III, and IV/V was performed. The modified Rankin Scale was used to assess functional outcome.

RESULTS:

Persistent deficits, modified Rankin Scale score deterioration, and impaired functional outcome occurred less frequently in ARUBA-eligible grade I/II patients compared with grade III to V patients combined (P = .04, P = .04, P = .03, respectively). Twenty-two of 39 patients (56%) unruptured grade I and II BAVMs were treated with surgery without and with preoperative embolization, and all had a modified Rankin Scale score of 0 to 1 at the last follow-up. All patients treated with surgery without and with preoperative embolization had radiographic cure at the last follow-up.

CONCLUSION:

The results of ARUBA-eligible and unruptured grade I/II patients overall show that excellent outcomes can be obtained in this subgroup of patients, especially with surgical management. Functional outcomes for ARUBA-eligible patients were similar to those of patients who were randomized to medical management in ARUBA. On the basis of these data, in appropriately selected patients, we recommend treatment for low-grade BAVMs.

Treatment of giant and large fusiform middle cerebral artery aneurysms with excision and interposition radial artery graft in a 4-year-old child: case report

BACKGROUND AND IMPORTANCE

We report an unusual case of complex giant and large fusiform aneurysms not amenable for clipping or coiling in a 4-year-old child managed with aneurysm resection and radial artery interposition graft.

CLINICAL PRESENTATION

A 4-year-old child presented with repeated severe headache and vomiting. Computed tomography, magnetic resonance imaging, and magnetic resonance angiography and digital subtraction angiography showed a giant fusiform aneurysm on the right middle cerebral artery (MCA). Because of the complex shape, endovascular treatment or clip reconstruction was not possible, and a bypass procedure was planned. Right frontotemporal craniotomy and orbitotomy was performed. Two aneurysms involving the M1 segment of the MCA were found in line, 1 giant, and the other large in size. The aneurysms were resected and treated with short radial artery interposition graft, which was narrower than the proximal or distal MCA. The child recovered normally, and the bypass was patent after 1 year.

CONCLUSION

Large fusiform MCA aneurysms may be difficult to treat, but there are treatment options that include a bypass procedure. Resection and short interposition radial artery graft is an excellent but rare treatment option in a very young child. This was a very successful treatment in this child.

Multimodality treatment of complex unruptured cavernous and paraclinoid aneurysms

BACKGROUND

Unruptured aneurysms of the cavernous and paraclinoid internal carotid artery can be approached via microsurgical and endovascular approaches. Trends in treatment reflect a steady shift toward endovascular techniques.

OBJECTIVE

To analyze our results with multimodal treatment.

METHODS

We reviewed patients with unruptured cavernous and paraclinoid internal carotid artery aneurysms proximal to the posterior communicating artery treated at a single center from 2007 to 2012. Treatment included 4 groups: (1) stent-assisted coiling, (2) pipeline endovascular device (PED) flow diverter, (3) clipping, and (4) trapping/bypass. Follow-up was 2 to 60 months.

RESULTS

The 109 aneurysms in 102 patients were studied with the following treatment groupings: 41 were done with stent-assisted coiling, 24 with Pipeline endovascular device, 24 by microsurgical clipping, and 20 by trap/bypass. Group: (1) two percent had delayed significant intraparenchymal hemorrhage; (2) thirteen percent had central nerve palsies, 8% had small asymptomatic infarcts, and 4% had small, asymptomatic remote-site hemorrhages; (3) twenty-nine percent of patients suffered from transient central nerve palsies, 4% experienced major stroke, and 8% had small intracerebral hemorrhages; (4) thirty-five percent had transient central nerve palsies, 10% had strokes, and 10% had intracerebral hemorrhages. In terms of follow-up obliteration, 83% had complete/nearly complete obliteration at last follow-up, 17% had residual aneurysms, and 10% required retreatment. Ninety-six percent of group 1 (35/38), 100% of group 2 (23/23), 100% of group 3 (21/21), and 95% of group 4 had modified Rankin Scale scores of 0 to 1.

CONCLUSION

Treatment of these aneurysms can be carried out with acceptable rates of morbidity. Careful patient selection is crucial for optimal outcome. Endovascular treatment volumes likely will continue to predominate over microsurgical techniques as changing skill sets evolve in neurosurgery, but individualized application of all available treatment options will continue.

A case of malignant peripheral nerve sheath tumor of the hypoglossal nerve after stereotactic radiosurgery treatment

Objectives Hypoglossal schwannomas are rare. Surgical resection has been the standard treatment modality. Radiosurgery has been increasingly used for treatment. Radiation-associated secondary malignancy/malignant transformation has not been documented in the literature for the treatment of nonvestibular schwannomas. Setting The patient was a 52-year-old man with an enlarging high cervical/skull base lesion 8.5 years after CyberKnife treatment of a presumed vagal schwannoma. A decision was made for surgical resection, and the tumor was found to originate from the hypoglossal nerve intraoperatively. Final pathology diagnosis was malignant peripheral nerve sheath tumor. Results Patient had a gross total resection. Three months after resection, he received fractionated radiation of 50 Gy in 25 fractions and a boost gamma knife radiosurgery of 10 Gy to the 50% isodose surface. He remained tumor free on repeat magnetic resonance imaging 9 months after the resection. Conclusion Although extremely rare, radiation treatment of nonvestibular schwannomas can potentially cause malignant transformation.

Bypass using V2-V3 segment of the vertebral artery as donor or recipient: technical nuances and results

OBJECTIVE

Surgical revascularization (bypass) technique has been used to treat vascular diseases of the posterior circulation, including ischemia, aneurysms, and tumors encasing a major artery. We focused on procedures using the V2-V3 segment of the vertebral artery (VA) as either the donor or recipient of the bypass. We have described technical nuances developed over time and evaluated the surgical results of those cases.

METHODS

Data on all patients who underwent bypasses using the V2-V3 segment were collected retrospectively from a prospectively maintained database.

RESULTS

Twenty patients had bypasses using V2-V3 distal VA as either the donor (13) or recipient (7); 19 patients had an intervening graft and in 1 patient, the VA was used for reimplantation of the posterior inferior cerebellar artery. Except for 1 patient, who died during the perioperative period, the mean follow-up time for the rest of the patients was 24.7 months (range 1-72 months). One patient developed postoperative stroke. One radial artery graft occluded, and a redo saphenous vein graft also occluded in the same patient. All the other bypasses were patent without flow limitation at the latest follow-up. Fourteen patients had a modified Rankin Scale score of 2 or better at the latest follow-up, and 2 died of unrelated causes as the result of their tumors.

CONCLUSIONS

The V2-V3 segment of the VA can be used both as a donor and a recipient for bypass surgery. Using the technical steps perfected over time, we are able to achieve surgical results with high rate of graft patency and good functional outcome in patients.

Flow diversion radial artery bypass graft coupled with terminal basilar artery occlusion for the treatment of complex basilar apex aneurysms: operative nuances

BACKGROUND

A subset of basilar apex aneurysms are unsuitable for either primary microsurgical clipping or endovascular coiling. These complex aneurysms can be treated by terminal basilar artery occlusion, but only if collateral circulation is adequate. To circumvent these complications, a high-flow vertebral artery-posterior cerebral artery or middle cerebral artery-posterior cerebral artery bypass may be performed to create an adequate collateral circulation to allow treatment of the aneurysm by basilar artery occlusion and/or clipping.

OBJECTIVE

To discuss the operative nuances of this approach in the case of a 47-year-old man with progressive hemiparesis resulting from brainstem compression from a giant, unruptured basilar apex aneurysm with absent posterior communicating artery collaterals and incorporation of bilateral superior cerebellar arteries and posterior cerebral arteries within the aneurysm neck.

METHODS

The patient underwent a staged bypass from V3 to P2 coupled with terminal basilar artery occlusion.

RESULTS

The patient initially presented as modified Rankin Scale score 2 with right hemiparesis. The aneurysm ruptured after the first stage of the operation, and the patient underwent a V3 to P2 bypass the next day. His postprocedural neurologic decline improved at the 14-month follow-up to modified Rankin Scale score 2, with substantial reduction in aneurysm size observed at 9 months. The outcomes for 3 other bypass cases for basilar apex aneurysms are also summarized.

CONCLUSION

: We discuss the indications, preoperative diagnostic workup, operative management, and postoperative outcomes in managing challenging basilar apex aneurysms. In our experience, high-flow bypass procedures with or without hunterian ligation in the treatment of these aneurysms are well tolerated with good long-term results.

Accuracy of computational cerebral aneurysm hemodynamics using patient-specific endovascular measurements

Computational hemodynamic simulations of cerebral aneurysms have traditionally relied on stereotypical boundary conditions (such as blood flow velocity and blood pressure) derived from published values as patient-specific measurements are unavailable or difficult to collect. However, controversy persists over the necessity of incorporating such patient-specific conditions into computational analyses. We perform simulations using both endovascularly-derived patient-specific and typical literature-derived inflow and outflow boundary conditions. Detailed three-dimensional anatomical models of the cerebral vasculature are developed from rotational angiography data, and blood flow velocity and pressure are measured in situ by a dual-sensor pressure and velocity endovascular guidewire at multiple peri-aneurysmal locations in 10 unruptured cerebral aneurysms. These measurements are used to define inflow and outflow boundary conditions for computational hemodynamic models of the aneurysms. The additional in situ measurements which are not prescribed in the simulation are then used to assess the accuracy of the simulated flow velocity and pressure drop. Simulated velocities using patient-specific boundary conditions show good agreement with the guidewire measurements at measurement locations inside the domain, with no bias in the agreement and a random scatter of ≈25%. Simulated velocities using the simplified, literature-derived values show a systematic bias and over-predicted velocity by ≈30% with a random scatter of ≈40%. Computational hemodynamics using endovascularly measured patient-specific boundary conditions have the potential to improve treatment predictions as they provide more accurate and precise results of the aneurysmal hemodynamics than those based on commonly accepted reference values for boundary conditions.

Monitoring Flow in Extracranial-Intracranial Bypass Grafts Using Duplex Ultrasonography: A Single-Center Experience in 80 Grafts Over 8 Years

BACKGROUND:

High-flow extracranial-intracranial (EC-IC) bypass is performed by using radial artery graphs (RAGs) or saphenous vein grafts (SVGs) for various pathologies such as aneurysms, ischemia, and skull-base tumors. Quantifying the acceptable amount of blood flow to maintain proper cerebral perfusion has not been well established, nor have the variables that influence flow been determined.

OBJECTIVE:

To identify the normative range of blood flow through extracranial-intracranial RAGs and SVGs as measured by duplex ultrasonography. Multiple variables were evaluated to better understand their influence of graft flow.

METHODS:

All EC-IC grafts performed at Harborview Medical Center from 2005 to 2012 were retrospectively reviewed for this cohort study. Daily extracranial graft duplex ultrasonography with flow volumes and transcranial graft Doppler were examined, as were short- and long-term outcomes. Both ischemic and hyperemic events were evaluated in further detail.

RESULTS:

Eighty monitorable high-flow EC-IC bypasses were performed over the 8-year period. Sixty-five bypasses were performed by using RAGs and 15 were performed with SVGs. The average flow was 133 mL/min for RAGs and 160 mL/min for SVGs (P = .25). For both RAG and SVG groups, the donor and recipient vessel selected significantly impacted flow. For the RAG group only, preoperative graft diameter, postoperative hematocrit, and postoperative date significantly influenced flow. A 1-week average of &gt;200 mL/min was 100% sensitive to cerebral hyperemia syndrome.

CONCLUSION:

This study establishes the normative range of duplex ultrasonographic flow after high-flow EC-IC bypass, as well the usefulness and practicality of such monitoring as a surrogate to flow in the postoperative period.

Intraventricular tissue plasminogen activator for the prevention of vasospasm and hydrocephalus after aneurysmal subarachnoid hemorrhage

BACKGROUND

The sequelae of aneurysmal subarachnoid hemorrhage (SAH) include vasospasm and hydrocephalus.

OBJECTIVE

To assess whether intraventricular tissue plasminogen activator (tPA) results in less vasospasm, fewer angioplasties, or fewer cerebrospinal fluid shunting procedures.

METHODS

41 patients (tPA group, Hunt and Hess 3, 4, 5) from 2007 to 2008 received intraventricular tPA and lumbar drainage for a minimum of 5 days (range 5-7 days) and were compared to a matched group of 35 patients from 2006 to 2007 (Control, HH 3, 4, 5). Statistical comparison was done by t test analysis or Fisher exact tests and data are expressed as average+/-standard error of the mean.

RESULTS

There were no significant differences in demographic data, although the tPA group had a trend toward more surgical patients. The tPA group of patients had a significantly higher modified Fisher grade than controls (P<.001) and had a significantly better Hunt and Hess grade than controls (P<.03). The angioplasty rate was significantly lower among the tPA patients (15.0%+/-5.6) than controls (40.0%+/-8.5, P=.019). The number of days spent in severe vasospasm normalized over the 14-day monitoring period by transcranial Doppler was significantly lower in the tPA group (0.09+/-0.02) than controls (0.17+/-0.03). The shunt rate was significantly lower among tPA patients (17.5%+/-6.0) than controls (42.8%+/-8.6). There were 2 clinically silent tract hemorrhages in the tPA group (4.8%).

CONCLUSION

Intraventricular tPA is a safe and effective treatment for reducing both angioplasty and shunting rates in patients with SAH H&H Grades 3 to 5. A randomized trial is indicated.

Incidence of microemboli and correlation with platelet inhibition in aneurysmal flow diversion

Flow-diverting stents have been associated with embolic and hemorrhagic complications, but the rate of procedure-related microemboli is unknown. Using transcranial Doppler sonography, we measured the rate of microemboli in 23 patients treated with flow-diverting stents. Patients received preprocedural dual antiplatelet medications and intraprocedural heparinization. Point-of-care platelet reactivity testing was performed before the procedure, and nonresponders (>213 P2Y12/ADP receptor reactivity units) received additional thienopyridine. Transcranial Doppler sonography was performed within 12-24 hours. Microemboli were detected in 3 patients (13%), 2 of whom were initially nonresponders. There was no association between the presence of microemboli and procedural or neurologic complications, aneurysm size, number of stents, or procedure time. Eight procedures (34.8%) required additional thienopyridine for inadequate platelet inhibition, and 3 required further treatment for persistent nonresponse to point-of-care platelet reactivity testing. There were 6 technical and 2 postoperative complications; none were associated with inadequate platelet inhibition or microemboli. The combination of routine point-of-care platelet reactivity testing and postprocedural microembolic monitoring may help identify patients at risk for thromboembolic complications after flow-diverting stents.