New generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT): a study protocol for a multicenter randomized controlled trial.

PURPOSE: Aneurysm recanalization constitutes a limitation in the endovascular treatment of intracranial aneurysms using conventional bare platinum coils. The development of platinum coils coupled with hydrogel polymers aimed at decreasing the rates of recurrence by way of enhanced coil packing density and biological healing within the aneurysm. While enhanced occlusion and durability has been shown for the first generation hydrogel coils, their use was limited by technical challenges. Less data is available regarding the second-generation hydrogel coils which have been designed to perform like bare platinum coils. METHODS: The new generation Hydrogel Endovascular Aneurysm Treatment Trial (HEAT) is a multicenter, randomized controlled trial that compares the health outcomes of the second-generation HydroCoil Embolic System with bare platinum coils in the endovascular intracranial aneurysms. The primary endpoint is aneurysm recurrence, defined as any progression on the Raymond aneurysm scale, over a 24-month follow-up period. Secondary endpoints include packing density, functional independence, procedural adverse events, mortality rate, initial complete occlusion, aneurysm retreatment, hemorrhage from treated aneurysm, and any aneurysm recurrence. RESULTS: Patient recruitment initiated in June 2011 and ended in January 2016 in 46 centers. Six hundred eligible patients diagnosed with an intracranial aneurysm, ruptured or unruptured were randomly assigned to one of the two treatment arms. CONCLUSION: The HEAT trial compares the durability, imaging, and clinical outcomes of the second-generation hydrogel versus bare platinum coils in the endovascular treatment of ruptured or unruptured intracranial aneurysms. The results of this trial may further inform current endovascular treatment guidelines based on observed long-term outcomes.

Real-Time MRI-Guided Stereotactic Aspiration of Spontaneous Intracerebral Hematoma: A Preclinical Feasibility Study.

BACKGROUND: Minimally invasive surgical techniques have reinvigorated the role of surgical options for spontaneous intracranial hematomas; however, they are limited by the lack of real-time feedback on the extent of hematoma evacuation. OBJECTIVE: To describe the development of a MRI-guided catheter-based aspiration system, the ClearPoint Pursuit Neuroaspiration Device (ClearPoint Neuro) and validation in phantom models. METHODS: In this preclinical experimental trial, 8 phantom brains with skull models were created to simulate an intracranial hematoma with 2 clot sizes, 30 cc (small clot) and 60 cc (large clot). After registration, the aspiration catheter (Pursuit device) was aligned to the desired planned trajectory. The aspiration of the clot was performed under real-time MRI scan in 3 orthogonal views. The primary end point was reduction of the clot volume to less than 15 cc or 70% of the original clot volume. RESULTS: Successful completion of clot evacuation was achieved in all models. The average postaspiration clot volume was 9.5 cc (8.7 cc for small clots and 10.2 cc for large clots). The average percentage reduction of clot volume was 76.3% (range 58.7%-85.2%). The average total procedure time (from frame registration to final postaspiration clot assessment) was 50 min. The average aspiration time was 6.9 min. CONCLUSION: This preclinical trial confirms the feasibility and efficacy of MRI-guided aspiration under real-time image guidance in simulation models for intracranial hematoma. Clinical use of the system in patients would further validate its efficacy and safety.

Normalization of Peri-Arteriovenous Malformation Hemodynamics Prior to Direct Microsurgery: 2-Dimensional Operative Video.

Arteriovenous malformations (AVMs) are highly complex vascular lesions characterized by abnormal connections between arteries and an intervening nidus. Definitive and safe treatment of AVMs may require the combination of multiple treatment modalities to address the various complex features of the AVM.1 Endovascular embolization can be used as an adjuvant to surgery in order to control deep feeders, reduce flow, and address high-risk features such as aneurysms. In addition, by progressively reducing the AVM flow, staged embolization can lead to normalization of peri-AVM hemodynamics and therefore may decrease the risk of postresection hemorrhage.2,3 In this operative video, we present a case of a 41-yr-old female who presented with progressively worsening left-sided hemiparesis. Magnetic resonance imaging (MRI) and angiography revealed a complex right fronto-parietal AVM with significant associated edema, likely due to the vascular steal phenomenon. The area of edema, which included the motor cortex, was thought to be at high risk for postoperative hemorrhage from normal perfusion pressure breakthrough. We therefore decided to proceed with staged presurgical embolization to gradually normalize the perilesional hemodynamics, and therefore possibly reduce the risk of postoperative morbidity. The patient underwent 3 embolization sessions at 6-wk intervals. An MRI after the last embolization showed near-complete resolution of the fluid-attenuated inversion-recovery (FLAIR) signal around the AVM. Microsurgical resection was performed on the day after the last embolization. The patient tolerated the procedure well and was discharged at her neurological baseline with mild contralateral hemiparesis, which has continued to improve at follow-up. Postoperative angiography showed complete resection of the AVM. The patient consented to the procedure as shown in this operative video and gave informed written consent for use of her images in publication.

Quality of Life of Patients with Unruptured Intracranial Aneurysms Before and After Endovascular Coiling: A HEAT Trial Secondary Study and Systematic Review of the Literature.

BACKGROUND: The study of quality of life (QOL) in patients with asymptomatic diseases receiving interventional treatment provides an essential metric for the assessment of procedural benefits in the surgical patient population. In this study, we analyzed QOL data collected from patients with unruptured intracranial aneurysms (UIAs) before and after endovascular coiling in the HEAT Trial, alongside a systematic review on QOL in unruptured brain aneurysms. METHODS: HEAT was a randomized controlled trial comparing recurrence rates in aneurysms treated with either bare platinum coils or hydrogel coils. Patients enrolled in this trial completed a short form-36 (SF-36) QOL questionnaire before treatment and at the 3- to 12- and 18- to 24-month follow-ups. The change in QOL before and after treatment was assessed. Regression analysis evaluated the effect of select baseline characteristics on QOL change. RESULTS: A total of 270 patients were eligible for analysis. There was an increase in the role physical (P = 0.043), vitality (P = 0.022), and emotional well-being (P < 0.001) QOL components at the 18- to 24-month follow-up compared with baseline scores. Regression analysis showed that age younger than 60 and absence of serious adverse events were associated with improved social functioning and vitality. The literature review showed a mixed effect of intervention on QOL in patients with UIAs. CONCLUSIONS: Our analysis has revealed that patients with 3- to 14-mm UIAs had improvements in some physical and emotional components of QOL at 18-24 months following aneurysm coiling in the HEAT study. The literature remains indeterminate on this issue. Further studies are needed to better understand the effects of the diagnosis of UIAs and their treatment on QOL.

Microvascular Decompression and Transposition of the 8th Cranial Nerve Using a Fenestrated Clip.

Neurovascular compression is a potential, yet rare cause of vertigo and unilateral tinnitus. Despite the high success rate of microvascular decompression (MVD) in other vascular compression syndromes, the outcome reported after MVD of the vestibulocochlear nerve is variable.1,2 The presence of combined symptoms of tinnitus and vertigo treated by MVD has demonstrated a higher predictive value for success.3 In this video, we present the case of a 68-year-old male who presented with vertigo and tinnitus refractory to medical management and vestibular therapy. Audiologic evaluation was normal apart from mild sensorineural hearing loss. Vestibular testing was suggestive of uncompensated right peripheral vestibulopathy. Magnetic resonance imaging with fast imaging employing steady-state acquisition sequences revealed vascular compression by the right anteroinferior cerebellar artery (AICA) at the cisternal component of vestibulocochlear nerve. After a multidisciplinary discussion, a microvascular decompression was performed through a right retrosigmoid craniotomy. The AICA was mobilized off the vestibulocochlear nerve and was secured to the petrous dura using a fenestrated clip. Indocyanine green angiography with Glow-800 was conducted before and after AICA transposition to confirm adequate flow through the mobilized vessel. Postoperatively, the patient's vestibular symptoms improved significantly. This case demonstrates that microvascular decompression can provide a satisfactory outcome in patients with unilateral tinnitus and vertigo associated with vascular compression in appropriately selected cases (Video 1).

Extended Lateral Orbital Craniotomy: Anatomic Study and Initial Clinical Series of a Novel Minimally Invasive Pterional Approach.

Background Of the minimally invasive "keyhole" alternatives to the pterional region, the supraorbital eyebrow approach is the most widely adopted. Yet it can prove disadvantageous when a more direct lateral microsurgical trajectory of attack to the Sylvian fissure and anterior middle fossa are needed. Objective The extended lateral orbital (XLO) approach was designed to be direct and minimally invasive, with the sphenoid ridge at the center of exposure. Methods Five injected cadaver heads were used for anatomic study of the XLO approach. The anatomic course of the frontalis branch of facial nerve was studied in relation to the XLO incision. Following XLO incision, the bone exposure was measured. The intracranial microsurgical exposure was assessed subjectively. Application of the technique in representative clinical operative cases is provided. Results The frontalis nerve was protected in the subgaleal fat pad, with an average minimum distance of 2.3 cm from the XLO incision. The mean calvarial area exposure was 4.95 cm 2 and consistently centered on the sphenoid ridge. Excellent access to ipsilateral Sylvian's fissure, perisylvian regions, and supra-/parasellar structures was possible. The main limitations related to exposure of the posterior Sylvian fissure and the expected limitations of microsurgical instrument manipulation from a smaller craniotomy. Conclusions The XLO approach is a minimally invasive keyhole approach to the pterional region that affords a unique lateral trajectory via a craniotomy centered on the sphenoid ridge. Excellent exposure to properly selected lesions is possible. The incision is at a safe distance from the frontalis branch and shows excellent cosmetic healing.

Vascular Transposition of the Superior Cerebellar Artery Using a Fenestrated Clip and Fibrin Glue in Trigeminal Neuralgia: 2-Dimensional Operative Video.

This is the case of an 86-yr-old gentleman who presented with left facial pain exacerbated by eating, drinking, chewing, and shaving (distribution: V2, V3). The patient was diagnosed with trigeminal neuralgia and was refractory to medications. Imaging showed a superior cerebellar artery (SCA) loop adjacent to the trigeminal nerve root entry zone and a decision to perform a microvascular decompression of the fifth nerve was presented to the patient. After patient informed consent was obtained, a standard 3 cm × 3 cm retrosigmoid craniotomy was performed with the patient in a supine head turned position and in reverse Trendelenburg. The arachnoid bands tethering the SCA to the trigeminal nerve were sharply divided. A slit was then made in the tentorium and a 3 mm fenestrated clip was then used to secure the transposed SCA away from the trigeminal nerve. The SCA proximal to this was slightly patulous in its course so a small amount of a fibrin glue was also used to secure the more proximal SCA to the tentorium. The patient was symptom-free postoperatively and no longer required medical therapy. Additionally, imaging was consistent with adequate separation of the nerve from adjacent vessels.1-5.

Utility of Augmented Reality Imaging (GLOW800) in Resection of Hemangioblastoma.

This is a surgical video that sheds light on the utility of a new imaging modality GLOW800 (Leica Microsystems, Wetzlar, Germany) in resection of vascular tumors. We describe the surgical resection of posterior fossa hemangioblastoma in 2 different patients after informed consent was obtained. In the first case no intraoperative angiographic imaging was used, while in the second case GLOW800 was used. Because of its ability to overlay the augmented reality view on the surgical field, it allowed for localization of highly vascular tumors as seen in the second patient. In addition, it helped in the confirmation of complete resection of the lesion. Another advantage of GLOW800 was that it allowed safe resection of the lesion in and around highly eloquent areas with a narrow surgical corridor (Video 1).

Surgical Outcomes with Midline versus Lateral Approaches for Cranial Base Chordomas: A Systematic Review and Meta-Analysis.

BACKGROUND: Cranial base chordomas are complex lesions centered on the clivus that surgically can be approached from either a midline or a lateral corridor. OBJECTIVE: To compare the surgical outcomes from midline versus lateral approaches by conducting a meta-analysis of the literature. METHODS: Studies were identified between 2000 and 2018. The primary outcome was gross total resection (GTR) rate. The secondary outcomes were recurrence rate and rates of cerebrospinal fluid (CSF) leak and new cranial nerve palsy. Odds ratios were calculated with a random-effect model using studies describing both approaches. An indirect (proportion) meta-analysis was performed pooling studies describing either of the approaches. Individual patient data were analyzed for differences in GTR or recurrence rate with different tumor extensions. RESULTS: Thirty-three studies were found suitable for indirect meta-analysis and 10 studies for direct meta-analysis. The overall odds of GTR with a midline approach compared with a lateral approach was 0.83 (95% confidence interval [CI], -0.43 to 1.62). The odds ratios for recurrence, CSF leak, and new cranial nerve palsy were 0.82 (95% CI, 0.26-2.56), 1.49 (95% CI, 0.14-15.5), and 0.14 (95% CI, 0.04-0.56), respectively. With individual patient data analysis, no statistically significant difference was observed in GTR or recurrence rates between the 2 approaches with different tumor extensions. CONCLUSIONS: The meta-analysis did not show any significant difference in GTR or recurrence rates between the midline versus lateral approaches. Tumor extension to different compartments did not affect the GTR or recurrence rates with either approach. In terms of complications, CSF leak rate was higher in midline approaches and cranial nerve palsy was higher in lateral approaches.

Balloon Occlusion Testing to Assess Retinal Collateral and Predict Visual Outcomes in the Management of a Fusiform Intraorbital Ophthalmic Artery Aneurysm: Technical Note and Literature Review.

BACKGROUND AND IMPORTANCE: Aneurysms of the ophthalmic artery (OA) within the orbit and optic canal are extremely rare. Given the peripheral location of these aneurysms and the fact that most are fusiform, parent artery occlusion is preferred for symptomatic aneurysms. However, the impact of OA occlusion on vision is not always innocuous. Balloon occlusion testing (BOT) of the OA has the potential to gauge the possibility of visual compromise, in addition to assessing collaterals. While BOT has been assessed for carotid artery occlusion, its role in OA occlusion has not been well defined. CLINICAL PRESENTATION: We describe a patient with a 6-mm intracanalicular OA aneurysm who was treated with endovascular coil embolization of the aneurysm and occlusion of the parent artery. We performed a 30-min balloon occlusion test, in which we verified intact visual and neurological function. Collateral vascularity was confirmed. Complete occlusion was achieved and the patient recovered with intact visual and neurological function. We provide a review of literature pertaining to parent artery occlusion of OA aneurysms that occur within optic canal and orbit. A brief note on anatomy of OA and collaterals is provided. CONCLUSION: Endovascular parent artery occlusion is an effective treatment for OA aneurysms that occur in optic canal and orbit. Assessment of effect of occlusion on vision is important. BOT can assess this and provide valuable information. Recovery or preservation of visual function is highly dependent on preoperative visual status.

Lateral supracerebellar infratentorial approach for pontomesencephalic cavernous malformations.

Cavernomas at the posterolateral pontomesencephalic surface can be approached from a lateral infratentorial supracerebellar corridor. In this surgical video, we demonstrate two cases of brainstem cavernomas resected through a lateral supracerebellar infratentorial approach. A supine position with lateral turn of the head was used along with significant reverse Trendelenburg to allow the cerebellum to fall away with gravity from the tentorium. After exposure of the posterior surface of the brainstem between the tentorium and the superior cerebellar surface with aid of neuronavigation, the cavernomas were safely resected. The video can be found here: https://youtu.be/fUDdaprg26Y.

Treatment Strategy of a Patient With a Brain Arteriovenous Malformation and Cranial Dural Fistula: 2-Dimensional Operative Video.

We present the case of a 56-yr-old right-handed male, after informed consent was obtained, who presented with acute confusion and agitation, on the background of a remote history of an uncomplicated resection of a left parietal grade 2 glioma. Imaging revealed a large, acute right temporal intracerebral hemorrhage (ICH). Standard vascular workup for the cause of the ICH included catheter angiography. No direct cause of the hemorrhage was revealed; however, a high grade parasagittal dural arteriovenous fistula (DAVF) with cortical venous reflux was noted close to the prior craniotomy site. The venous reflux was towards the left hemisphere, but it was hypothesized that similar reflux on the right side may have been present and was not presently evident due to thrombosis. The DAVF was embolized by endovascular means, followed by evacuation of the hematoma. Follow-up angiogram 7 mo later revealed a high-flow, right superior temporal cortical arteriovenous malformation (AVM). The DAVF unfortunately had also progressed. Endovascular occlusion of both lesions was attempted but was not successful. Subsequently, microsurgical resection for both the vascular malformations was performed with careful pre- and intraoperative planning to obtain a successful clinical and angiographic result. In this video, we summarize diagnostic and therapeutic nuances that have broad implications for the workup of ICH and the strategic management of a unique scenario involving a brain AVM and high-grade cranial dural fistula in the same patient. Prior to each procedure, informed consent was obtained from the patient, which includes consent for publication.

Tulip Giant Aneurysm Amputation and "Shingle Clip Cut Clip" Technique for Microsurgical Reconstruction of a Giant Thrombosed Middle Cerebral Artery Aneurysm.

In this video, we present the case of a 61-year-old female who was brought to the emergency department after she had partial complex seizures. Computed tomography and magnetic resonance imaging of the brain revealed a right temporal lobe mass, which was initially thought to be a tumor. The patient was therefore referred to us for further management. The round nature of the lesion raised suspicion for an aneurysm. Computed tomography angiography was performed, followed by a diagnostic conventional cerebral angiogram, and confirmed the presence of a giant thrombosed aneurysm. Giant aneurysms represent 3%-5% of all cerebral aneurysms.1 They are more common in females with a ratio of 2:1 to 3:1.1 They have a high risk of rupture up to 50% in the posterior circulation and 40% in the anterior circulation over 5 years according to the International Study of Unruptured Intracranial Aneurysms Investigators.2,3 Their treatment can be complex and treacherous. Treatment options vary widely from parent artery sacrifice in select cases to clip reconstruction to an array of endovascular approaches such as flow diversion. In some cases a combination of both open and endovascular approaches might be necessary.4-8 In our case, we opted for an open surgical clip reconstruction. A superior temporal artery-middle cerebral artery bypass was attempted to allow for trapping of the aneurysm without risking ischemic complication distal to it. Unfortunately, the patient's vessels were too atherosclerotic to maintain patency. A strategy was then devised, which consisted of cutting the dome of the aneurysm and clearing the distal two thirds of the clot ("tulip technique") and then completing thrombus resection under temporary occlusion. Once clot removal was completed, the aneurysm was clipped using the "shingle clip cut clip" technique (Video 1). The patient's postoperative course was uneventful, and the patient remained seizure free.

Microsurgical Treatment of Foramen Magnum Cognard Type V Dural Arteriovenous Fistula: 2-Dimensional Operative Video.

Cognard type V dural fistulas represent a rare and unique entity, and present clinically with myelopathy. They are frequently located around the foramen magnum and are most commonly fed by dural branches of the vertebral and external carotid artery. Detection requires meticulous angiography to define the angioarchitecture of the fistula, which in turn defines the treatment modality. We present the case of a 63 yr old woman, after informed consent was obtained, with prolonged, severe and progressive lower extremity myelopathy for 6 yr, with T2-weighted signal changes in the thoracic spinal cord on magnetic resonance imaging (MRI). Cervical MRI was unremarkable. Following computed tomography (CT), angiography of the spinal canal that revealed tortuous and dilated veins on the thoracic spinal cord surface, catheter angiography was performed. This demonstrated a fistula in relation to a dural branch of left vertebral artery with a characteristic single draining vein coursing caudally to the thoracic level, with delayed outflow suggestive of venous hypertension. Given the fact that the dural feeder was tortuous and relatively small, thus, precluding distal microcatheter access, and with presence of a single accessible draining vein, microsurgical treatment was preferred. Following a midline suboccipital craniotomy in prone position, a limited vertical dural opening was performed. Careful microsurgical arachnoid dissection revealed the arterialized draining vein with the aid of Indocyanine Green angiography. The draining vein was clipped, coagulated, and disconnected. Postoperative recovery was uneventful and the patient is undergoing rehabilitation therapy. Follow-up angiography showed complete elimination of the fistula. Salient teaching points are narrated at conclusion.

Awake Surgery for Brain Vascular Malformations and Moyamoya Disease.

OBJECTIVE: Although a significant amount of experience has accumulated for awake procedures for brain tumor, epilepsy, and carotid surgery, its utility for intracranial neurovascular indications remains largely undefined. Awake surgery for select neurovascular cases offers the advantage of precise brain mapping and robust neurologic monitoring during surgery for lesions in eloquent areas, avoidance of potential hemodynamic instability, and possible faster recovery. It also opens the window for perilesional epileptogenic tissue resection with potentially less risk for iatrogenic injury. METHODS: Institutional review board approval was obtained for a retrospective review of awake surgeries for intracranial neurovascular indications over the past 36 months from a prospectively maintained quality database. We reviewed patients' clinical indications, clinical and imaging parameters, and postoperative outcomes. RESULTS: Eight consecutive patients underwent 9 intracranial neurovascular awake procedures conducted by the senior author. A standardized "sedated-awake-sedated" protocol was used in all 8 patients. For the 2 patients with arteriovenous malformations and the 3 patients with cavernoma, awake brain surface and white matter mapping was performed before and during microsurgical resection. A neurological examination was obtained periodically throughout all 5 procedures. There were no intraoperative or perioperative complications. Hypotension was avoided during the 2 Moyamoya revascularization procedures in the patient with a history of labile blood pressure. Postoperative imaging confirmed complete arteriovenous malformation and cavernoma resections. No new neurologic deficits or new-onset seizures were noted on 3-month follow-up. CONCLUSIONS: Awake surgery appears to be safe for select patients with intracranial neurovascular pathologies. Potential advantages include greater safety, shorter length of stay, and reduced cost.