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A wide range of diseases can involve the foramen magnum and cranial-vertebral junction (CVJ). Among them, vascular cases represent infrequent pathologies when compared with development disorders, trauma, and tumors. In spite of this, different vascular pathologies can occur at the CVJ, like posterior circulation aneurysms (saccular or fusiform/dissecting vertebral artery—posterior inferior cerebellar artery aneurysms and distal posterior inferior cerebellar artery aneurysms), arteriovenous malformations at the medulla oblongata or cervico-medullary junction and dural arteriovenous fistulas (DAVFs) of foramen magnum, hypoglossal canal, jugular foramen, marginal sinus and cervico-medullary junction. Surgery, endovascular treatment, and radiosurgery are all considered as treatment options for vascular diseases at the CVJ. Nevertheless, considering possible complications deriving from different treatment strategies, a multidisciplinary team evaluation is required. When surgical treatment is preferred, different approaches directed toward the CVJ can be used, e.g., midline suboccipital or far-lateral approach with or without extension to the high cervical region. Thus, total knowledge of CVJ neurovascular anatomy and good surgical exposure are both mandatory to reduce cranial nerves manipulation during surgical maneuvers. The exact location of the pathology and regional anatomy strictly influence surgical and clinical outcome. In this chapter, we review the technical nuances of approaches and surgical outcomes for aneurysm and arteriovenous malformations (including dural AVFs) of this region.

Craniopharyngiomas (CPs) are rare, benign tumors derived from Rathke's pouch, known for their high recurrence rates and associated morbidity and mortality. Despite significant investigation on risk factors for recurrence, a lack of consensus persists. Recent research suggests that specific histopathological and molecular characteristics are prognostic for disease progression. In this systematic review, we analyzed and consolidated key features of CPs that contribute to increased recurrence rates. This systematic review was performed in accordance with PRISMA guidelines. A search string was created with the keywords "craniopharyngioma," "histology," "histopathology," "molecular," and "recurrence." Literature was collected from 2006 to 2016 on the PubMed/Medline and Web of Science databases. The initial search resulted in 242 papers, examined with inclusion and exclusion criteria. The final review included a total of 37 studies, 36 primary studies covering a total of 1461 patients and 1 previous meta-analysis. Cystic lesions and whorl-like arrays were found to be associated with increased recurrence, while previously considered reactive gliosis and finger-shaped protrusions were not. The genetic elements found to be associated with increased risk of recurrence were Ki-67, Ep-CAM, PTTG-1, survivin, and certain RAR isotypes, as well as the glycoproteins osteonectin and chemokines CXCL12/CXCR4. The effects of VEGF, HIF-1α, and p53, despite extensive study, yielded conflicting results. Certain histopathological and molecular characteristics of CPs provide insight into their pathogenesis, likelihood of recurrence, and potential novel targets for therapy.

Large middle cerebral artery (MCA) bifurcation aneurysms are known vascular lesions that are usually symptomatic but often difficult to treat (whether with open or endovascular techniques), especially when the M2 branches originate from the aneurysm dome.1-7 The challenge lies in securing the aneurysm while fully maintaining the flow in the vessels arising from the dome. Standard microsurgical clipping or endovascular techniques are not feasible in perfectly treating these aneurysms. Revascularization of the MCA branches with bypass and trapping of the aneurysm is often necessary. Here, we present a case of a large complex partially thrombosed right MCA bifurcation aneurysm with both the superior and the inferior divisions arising from the dome. The patient initially presented with a right MCA stroke and left hemiparesis. Using radial artery as an interposition graft, 2 bypasses-internal maxillary artery to the inferior division and superficial temporal artery to the superior division-were performed. The aneurysm was trapped and decompressed by placing clips at the M1 terminus and the M2 origins. Intraoperative angiography and postoperative NOVA (VasSol Inc.) magnetic resonance angiography (MRA) confirmed patency and excellent flow in the bypass grafts. The patient's postoperative course was uncomplicated, and at 2-mo follow-up, had significant improvement of her hemiparesis. The patient provided informed consent for the procedure.

Endovascular and surgical techniques are conventional options for treating intracranial aneurysms, but criteria for selecting an optimal approach for individual patients remain variable across practitioners and institutions. While endovascular and surgical approaches are generally used alone, both modalities combined in single patients can produce efficacious outcomes. The aim of this study was to evaluate outcomes of combined, concomitant endovascular and surgical modalities in the treatment of multiple and/or complex aneurysms in single patients. Indications, sequencing rationale, and categorization for multimodality treatments are reviewed. All intracranial aneurysms treated at our institution from 2004 to 2014 were reviewed. Single patients who had undergone concomitant endovascular and surgical treatments were eligible for participation in our study. Demographic data and clinical presentation parameters, including location, size, and morphological features of lesions, treatment sequencing, and outcomes were recorded. Our cohort consisted of 27 patients with 57 aneurysms who received concomitant endovascular and surgical treatment of their aneurysm(s). One patient arrived to us after he had an aneurysm clipped at an outside institution and then required treatment for a contralateral ruptured aneurysm. 66.7% of patients were diagnosed with subarachnoid hemorrhage. These were subdivided according to therapeutic approach: clipping and coiling (CL+CO), clipping and stenting (CL+ST), bypass and endovascular parent vessel occlusion (PVO) (BY+PVO), attempted clipping then stenting, and bypass followed by stenting. Glasgow Outcome Scale was as follows: CL-CO-Multiple, 4.17 (five in unruptured patients, 3.75 in ruptured); CO-CL-Multiple, five (all patients had a ruptured aneurysm); CL-CO-Single, three (all patients had a ruptured aneurysm); CO-CL-Single, five (all patients had a ruptured aneurysm). No patients suffered a new neurological deficit as a result of treatment. A total of two mortalities were documented. Concomitant, mutimodality endovascular and surgical therapy may offer a safe and potentially more effective paradigm than single modality approaches for the management of multiple, complex, or "failed" aneurysm treatments in selected patients.

The resection of tuberculum sellae meningiomas poses a challenge particularly when dealing with the medial aspect of the optic nerve. Dissection of the tumor off the optic nerve is usually carried out in the blind spot “behind” the optic nerve. We describe a contralateral approach for asymmetric tuberculum sellae meningiomas, allowing direct visualization of the medial optic nerve. Contralateral lateral supraorbital approach was performed, and complete tumor resection was achieved without any injury to the optic nerve. The contralateral approach for asymmetric tuberculum sellae meningioma is an efficient technique allowing improved visualization of the medial optic nerve.

BACKGROUND Large vestibular schwannomas (VSs) with brainstem compression are generally reserved for surgical resection. Surgical aggressiveness must be balanced with morbidity from cranial nerve injury. The purpose of the present investigation is to evaluate the clinical presentation, management modality, and patient outcomes following near total resection (NTR) vs gross total resection (GTR) of large VSs. OBJECTIVE To assess facial nerve outcome differences between GTR and NTR patient cohorts. METHODS Between January 2010 and March 2018, a retrospective chart review was completed to capture patients continuously who had VSs with Hannover grades T4a and T4b. NTR was decided upon intraoperatively. Primary data points were collected, including preoperative symptoms, tumor size, extent of resection, and postoperative neurological outcome. RESULTS A total of 37 patients underwent surgery for treatment of large and giant (grade 4a and 4b) VSs. Facial nerve integrity was preserved in 36 patients (97%) at the completion of surgery. A total of 27 patients underwent complete resection, and 10 had near total (>95%) resection. Among patients with GTR, 78% (21/27) had House-Brackmann (HB) grade I-II facial nerve function at follow-up, whereas 100% (10/10) of the group with NTR had HB grade I-II facial nerve function. Risk of meningitis, cerebrospinal fluid leak, and sinus thromboses were not statistically different between the 2 groups. There was no stroke, brainstem injury, or death. The mean follow-up was 36 mo. CONCLUSION NTR seems to offer a benefit in terms of facial nerve functional outcome compared to GTR in surgical management of large VSs without significant risk of recurrence.

Background: Recent reports have raised various concerns about the risk of vessel wall injury while withdrawing current laser-cut stent retrievers during active strut apposition to the vessel walls. The development of braided thrombectomy assist devices in conjunction with aspiration systems may be gentler on the fragile brain vessels and more optimized with regard to the radial force (RF) for vessel diameters of proximal (M1) and distal (M2) large vessel occlusions (LVOs). Methods: Mechanical bench testing of the RF was performed using a radial compression station mounted on a tensile testing machine. The total RF in newtons (N) generated in vessels with diameters ranging from 2.25 to 3 mm as seen in proximal LVOs (∼M1), and in vessel diameters ranging from 1.5 to 2.24 mm as seen in distal LVOs (∼M2), was measured. The outer diameter of each stent was recorded, and an RF ≤1 N was grouped as “low,” while an RF >1 N was grouped as “high” for this analysis. Results: The total RFs of all laser-cut stent retrievers were all higher in the simulated M2 vessels (>1 N) than in the M1 vessels (Conclusions: Novel braided thrombectomy assist devices in conjunction with aspiration systems have lower RFs than existing laser-cut stent retrievers in M1 and M2 vessel diameters. Further in vivo studies are needed to delineate the impact of lowering the RF on vessel wall integrity.

BACKGROUND Large vestibular schwannomas (VSs) with brainstem compression are generally reserved for surgical resection. Surgical aggressiveness must be balanced with morbidity from cranial nerve injury. The purpose of the present investigation is to evaluate the clinical presentation, management modality, and patient outcomes following near total resection (NTR) vs gross total resection (GTR) of large VSs. OBJECTIVE To assess facial nerve outcome differences between GTR and NTR patient cohorts. METHODS Between January 2010 and March 2018, a retrospective chart review was completed to capture patients continuously who had VSs with Hannover grades T4a and T4b. NTR was decided upon intraoperatively. Primary data points were collected, including preoperative symptoms, tumor size, extent of resection, and postoperative neurological outcome. RESULTS A total of 37 patients underwent surgery for treatment of large and giant (grade 4a and 4b) VSs. Facial nerve integrity was preserved in 36 patients (97%) at the completion of surgery. A total of 27 patients underwent complete resection, and 10 had near total (>95%) resection. Among patients with GTR, 78% (21/27) had House-Brackmann (HB) grade I-II facial nerve function at follow-up, whereas 100% (10/10) of the group with NTR had HB grade I-II facial nerve function. Risk of meningitis, cerebrospinal fluid leak, and sinus thromboses were not statistically different between the 2 groups. There was no stroke, brainstem injury, or death. The mean follow-up was 36 mo. CONCLUSION NTR seems to offer a benefit in terms of facial nerve functional outcome compared to GTR in surgical management of large VSs without significant risk of recurrence.

Dural arteriovenous fistulas (dAVFs) are rare vascular malformations of uncertain pathophysiology. If associated with cortical venous reflux, they present a significant risk of hemorrhage. We present a 69-year-old patient who presented with spontaneous right-sided symptomatic chronic subdural hematoma, which was evacuated via burr hole. Due to lack of history of prior trauma, computer tomography angiography was performed, which showed dilated convoluted vessels in the right occipital region and an enlarged right posterior cerebral artery, suspected to be an arteriovenous malformation or dAVF. Subsequent angiography demonstrated occipital tentorial dAVF with primary cortical venous reflux (Cognard III) and reflux into the transverse sinus, fed primarily from the petrosquamous branch of the middle meningeal artery and neuromeningeal trunk. The fistula was initially treated by transarterial endovascular embolization of the occipital artery and neuromeningeal trunk with Onyx, achieving complete obliteration. However, follow-up angiography demonstrated recurrence of the lesion fed from the contralateral middle meningeal artery and pial branches of the enlarged right posterior cerebral artery. Given the recruitment of the contralateral supply from the left middle meningeal artery and ipsilateral posterior cerebral artery, we felt that surgical disconnection of the fistula was the best option for the patient. An occipital craniotomy with disconnection of the fistula without isolation of the transverse sinus was performed ( Video 1 ), as published literature demonstrated lower intraoperative risk with disconnection only. The perioperative course was uneventful. Immediate postoperative and follow-up angiography demonstrated complete occlusion of the fistula.

Surgical treatment of large vestibular schwannomas is challenging. Both facial and cochlear nerves should be preserved in patients who have no neurological deficit preoperatively. In this 3-dimensional video, we present a 35-yr-old patient who presented with documented increase in the size of a known vestibular schwannoma over the span of 3 yr. Surgery was favored among all treatment options due to his young age and the tumor size. Informed consent was obtained. Semisitting surgery allowed for bimanual microdissection of the tumor capsule from the surrounding arachnoid and cranial nerves with 2 micro dissectors. The precision of microdissection is enhanced in the sitting position. Facial nerve stimulation remained stable at 0.05 mA. The auditory evoked potential remained unchanged during the surgery. Complete resection of the tumor and preservation of facial and cochlear nerves was achieved. The patient had a stable hearing grade B and a normal facial nerve function at 3-mo follow-up.

Introduction Accurate sizing of the Woven EndoBridge (WEB) device is of critical importance as it determines procedural safety and successful occlusion of wide neck bifurcation aneurysms. The aim of this study was to assess the ability of aneurysm volume to assist in accurate WEB size selection. Methods All patients with an intracranial aneurysm treated with the WEB SL or WEB SLS device between March 2019 and October 2019 were identified for this retrospective study. Aneurysm volumes were calculated with auto-segmentation using a three-dimensional volume rendering program on an independent Syngo workstation (Siemens Healthineers AG). Pearson correlation coefficients were calculated for aneurysm auto-segmented volumes and WEB volumes, as well as for aneurysm height × width and WEB height × width. Follow-up angiographic outcomes were collected at 6–9 months post-procedure. Results Twenty-nine aneurysms were evaluated by 3D rotational angiography. The correlation coefficient with WEB size was larger for auto-segmented aneurysm volumes (r = 0.979) compared to height × width measurements (r = 0.867). Using Fisher r-to-z transformations, we found the difference between the two correlations to be statistically significant (p = 0.0007). Follow-up angiography available in 13 subjects demonstrated an 85% complete aneurysm occlusion rate. Conclusion Aneurysm volumes are highly correlated with WEB volumes, with auto-segmentation volumes displaying statistically significant difference against conventional height by width measurements. These results suggest that volumetric measurements of aneurysm size provide a useful adjuvant measure to assist in appropriate size selection of the WEB device.

To investigate the usefulness of 3-dimensional computerized tomography angiography (3D-CTA) in the microsurgical management of anterior communicating artery (AcomA) aneurysms.Twenty-six consecutive patients with AcomA aneurysms (22 ruptured) underwent microsurgical clipping. Detailed angioanatomic assessment of the AcomA complex and operative approach was based on the 3D-CTA.The 3D-CTA showed a dominant proximal anterior cerebral artery (A1) segment in 61% and symmetric A1s in 39% of aneurysms. Dominant A1 segments presented with rotation of the AcomA complex toward the contralateral side in 63%, toward the ipsilateral side in 25%, and without rotation in 12%. With symmetric A1s, the AcomA was parallel to the coronal plane in 90% and a right-sided approach was carried out in these patients. In rotated AcomA complexes, the virtual 3D views were compared to determine the side of the approach. For superior projecting aneurysms, we determined that the approach from the side in which the A1-distal anterior cerebral artery (posterior communicating) angle was posterior was more favorable. For posterior projecting aneurysms, the approach from the side where the A1-distal anterior cerebral artery (posterior communicating) angle was more anterior was more favorable. For anteroinferior projecting aneurysms, an approach from the dominant A1 side was chosen regardless of AcomA complex rotation. Postoperative 3D-CTA showed complete exclusion of 24 aneurysms (92%) and 2 small remnants (2 mm). Outcome was excellent or good (modified Rankin score 0-2) in 88% of patients.Rotation of the AcomA complex and dome projection are important angioanatomic elements in determining the surgical exposure and side of the approach. This study illustrates the role of 3D-CTA in the management of these difficult lesions by individualizing the surgical approach.

Background The cervical carotid system has been used as a source of donor vessels for radial artery or saphenous vein grafts in cerebral bypass. Recently, internal maxillary artery to middle cerebral artery bypass has been described as an alternative, with reduction of graft length potentially correlating with improved patency. Objective To describe our experience using the forearm cephalic vein grafts for short segment internal maxillary artery to middle cerebral artery bypasses. Methods All vein grafts were harvested from the volar forearm between the proximal cubital fossa where the median cubital vein is confluent with the cephalic vein and the distal wrist. Results Six patients were treated with internal maxillary artery to middle cerebral artery bypass. In 4, the cephalic vein was used. Postoperative angiography demonstrated good filling of the grafts with robust distal flow. There were no upper extremity vascular complications. All but 1 patient (mortality) tolerated the procedure well. The other 3 patients returned to their neurological baseline with no new neurological deficit during follow-up. Conclusion The internal maxillary artery to middle cerebral artery "middle" flow bypass allows for shorter graft length with both the proximal and distal anastomoses within the same microsurgical field. These unique variable flow grafts represent an ideal opportunity for use of the cephalic vein of the forearm, which is more easily harvested than the wider saphenous vein graft and which has good match size to the M1/M2 segments of the middle cerebral artery. The vessel wall is supple, which facilitates handling during anastomosis. There is lower morbidity potential than utilization of the radial artery. Going forward, the cephalic vein will be our preferred choice for external carotid-internal carotid transplanted conduit bypass.

Superiorly projecting (SP) anterior communicating artery (AComA) aneurysms are typically described as a homogenous group. Clinically and microsurgically, these aneurysms vary in multiple important characteristics. We propose a microsurgical classification system for these complex aneurysms and review its implications regarding presentation, microsurgical techniques, and outcome. This retrospective analysis reviews patients undergoing clipping of SP AComA aneurysms (2005-2013). The classification system is based on the virtual plane created by the A2 segments and its relationship to the aneurysm. Aneurysm type was assessed by intraoperative images and videos. Type 1 is defined by bisection of the dome by the virtual plane. Type 2 is defined by dome projection posterior to this plane. Sagittal rotation of the plane defines type 3. We analyzed clinical presentation, morphology, angiographic characteristics, operative technique, and outcome relative to the classification types. There were 44 SP AComA aneurysms. 3D angiographic images predicted classification type in 83%. Type 1 presented more often with SAH (95.5%, p = 0.0046). There was no statistically significant difference between the types regarding patient demographics or aneurysm characteristics. In type 2, fenestrated clips were used frequently (87.5% p= 0.0016), and there was higher rate of intraoperative rupture (37.5%). Although there was no statistically significant difference between the types in respect to HH grade upon presentation, patients with type 2 aneurysms experienced higher rates of poor GOS (50%). The proposed classification system for SP AComA aneurysms has implications regarding surgical planning, micro-dissection, clipping, and outcome. Type 2 aneurysms carry significant surgical risk.

A 79-year-old woman presented to the emergency department following multiple falls in the previous week. Her past medical history was unremarkable except for chronic obstructive pulmonary disease. She was neurologically intact on arrival with normal laboratory data. Brain imaging revealed a right-sided sphenoid wing meningioma with considerable edema around it. Owing to her cognitive decline and recent symptoms, it was decided to proceed with surgical resection of the lesion. Considering her age and underlying disease, we planned to avoid probable complications of an aggressive resection. She underwent preoperative transarterial embolization with particles. In the supine position, a right pterional craniotomy with orbital extension was performed followed by tumor resection under microscopic magnification. One of the branches of the middle cerebral artery was engulfed by the tumor and could not be separated; therefore, the artery was cut to resect the tumor and then mobilized and reanastomosed under microscope. Doppler probe confirmed patency of the anastomosis. The patient recovered well from the surgery, experienced an uneventful hospital stay, and was discharged on postoperative day 10 after completely controlling her chronic obstructive pulmonary disease. Postoperative imaging did not show any signs of infarction, and the revascularized artery was patent on postoperative computed tomography angiography (Video 1).

OBJECTIVECerebral revascularization for carotid occlusion was previously a mainstay procedure for the cerebrovascular neurosurgeon. However, the 1985 extracranial-intracranial bypass trial and subsequently the Carotid Occlusion Surgery Study (COSS) provided level 1 evidence via randomized controlled trials against bypass for symptomatic atherosclerotic carotid occlusion disease. However, in a small number of patients optimal medical therapy fails, and some patients with flow-limiting stenosis develop a perfusion-dependent neurological examination. Therefore it is necessary to further stratify patients by risk to determine who may most benefit from this intervention as well as to determine perioperative morbidity in this high-risk patient population.METHODSA retrospective review was performed of all revascularization procedures done for symptomatic atherosclerotic cerebrovascular steno-occlusive disease. All patients undergoing revascularization after the publication of the COSS in 2011 were included. Perioperative morbidity and mortality were assessed as the primary outcome to determine safety of revascularization in this high-risk population. All patients had documented hypoperfusion on hemodynamic imaging.RESULTSAt total of 35 revascularization procedures were included in this review. The most common indication was for patients with recurrent strokes, who were receiving optimal medical therapy and who suffered from cerebrovascular steno-occlusion. At 30 days only 3 perioperative ischemic events were observed, 2 of which led to no long-term neurological deficit. Immediate graft patency was good, at 94%. Long term, no further strokes or ischemic events were observed, and graft patency remained high at 95%. There were no factors associated with perioperative ischemic events in the variables that were recorded.CONCLUSIONSCerebral revascularization may be done safely at high-volume cerebrovascular centers in high-risk patients in whom optimal medical therapy has failed. Further research must be done to develop an improved methodology of risk stratification for patients with symptomatic atherosclerotic cerebrovascular steno-occlusive disease to determine which patients may benefit from intervention. Given the high risk of recurrent stroke in certain patients, and the fact that patients fail medical therapy, surgical revascularization may provide the best method to ensure good long-term outcomes with manageable up-front risks.

Sylvian arteriovenous malformations (AVMs) are challenging lesions for surgical management. They are classified according to the Sugita classification based on the location of the nidus in the sylvian fissure: pure, lateral, medial, and deep. Resection of these lesions are fraught with risks, as it requires extensive arachnoid dissection in the sylvian fissure in close proximity to surrounding eloquent tissue, and the presence of en passage arteries can resemble feeding arteries. In this video illustration, the authors describe a complex, Spetzler-Martin Grade IV right sylvian AVM and its surgical resection. By Sugita classification, this was a medial sylvian AVM, with an associated flow related middle cerebral artery (MCA) bifurcation aneurysm. Informed consent was obtained from the patient prior to the procedures. The AVM was embolized preoperatively, and surgical resection was carried out via a pterional approach. The detail of the AVM resection is described in the video clip. Postoperative digital subtraction angiography showed complete excision of the lesion, and the patient was discharged to home on postoperative day 6 without any neurological deficit. In 1-yr follow-up angiogram, beside complete obliteration of the AVM, the flow-related MCA bifurcation aneurysm as well as the M1 and M2 vessels have decreased in size and are much less prominent in comparison to the pretreatment angiography.

Objects: Tectocerebellar dysraphism was first described by Padget and Lindenberg, together with occipital encephaloceles, cerebellar midline defects, tectal beaking, posterior kinked and displaced brainstem, and inverted cerebellum. We present a unique case of lipoencephalocele associated with tectocerebellar dysraphia and discuss the etiologies of both pathologies. The importance of the developmental comprehension of posterior fossa malformations is stressed. Case report: A 9-month-old girl in good health was referred for a huge occipital mass. On local examination, the patient had a rounded mass about 10×12cm in size, covered by alopecic skin, with a small eccentric dimple without any discharge. Magnetic resonance imaging revealed a lipoencephalocele with an intra- and an extracranial part, associated with tectocerebellar dysraphia with no aspect of inverted cerebellum as originally described in the tectocerebellar dysraphia. Resection of the extracranial part of the lipoma was performed for esthetic reasons. The intracranial part remained in situ. Conclusion: The association of lipoencephalocele and tectocerebellar dysraphia is extremely rare. The functional prognosis seems to be less severe for this combination than for the isolated tectocerebellar dysraphia. This association favors the dysraphic theory for the embryogenesis of the lipoma. It seems safe to restrict the surgery of this bizarre malformation to its external part

Flow-replacement revascularization and/or flow augmentation surgery may be necessary for safe deconstruction of complex middle cerebral artery (MCA) aneurysms. Roughly 1% to 2% of all MCA aneurysms have angiographic features prohibiting standard microsurgical or endovascular management. Consent was obtained from the patient for the production of this video. No International Review Board approval was required for the creation of this video. A 17-yr-old female presented at the age of 15 with headaches. At the time of initial presentation, the patient was found to have an MCA bifurcation aneurysm. Initially, the aneurysm was managed conservatively and followed. However, on follow-up imaging, the aneurysm was found to have grown and developed into a large, complex MCA bifurcation aneurysm. Patient underwent planned trapping and deconstruction of the aneurysm. An internal maxillary artery (IMAX) to MCA bypass was performed using a cephalic vein graph to a robust inferior MCA branch combined with an in Situ MCA to MCA bypass. Follow-up angiography showed complete occlusion of the aneurysm. Patient was neurologically intact at 1-yr follow-up. Microsurgery continues to be the best treatment option for complex MCA aneurysms. A surgeon trained in bypass is an absolute prerequisite for management of those lesions. The IMAX offers an ideal high flow donor vessel for subcranial to intracranial flow replacement, which was required for re-establishment of flow to the robust inferior MCA branch in this case. The superior branch of the MCA was less robust. Therefore, by recreating a more distal bifurcation, the in Situ side-to-side MCA-MCA bypass simplified the revascularization strategy.

Currently, there is no consensus in the initial management of small vestibular schwannomas (VSs). They are routinely watched and/or referred for radiosurgical treatment, although surgical removal is also an option. We hereby evaluate clinical outcomes of patients who have undergone surgical removal of smaller symptomatic VSs. Patients with vestibular schwannomas (grade T1–T3b according to Hannover classification) were reviewed. Patients with symptomatic tumors who underwent surgery were evaluated. Their preoperative hearing status was based on the guideline of the committee on hearing and equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) foundation. Their postoperative facial nerve function, hearing status, vestibular symptoms, and degree of tumor resection were assessed. Thirty patients were selected for surgery via a retrosigmoid approach based on their age, symptoms, and their own decision-making after discussion of management options. Most patients presented with hearing loss. Seventeen patients had useful hearing preoperatively. Among them, 10 patients (59%) preserved useful hearing (class A or B) postoperatively. MRI at 1-year follow-up confirmed complete resection in 26/29 patients. Also, 29 patients (97%) had HB grade I–II, and 1 patient had HB III at 1-year follow-up. Except for 1 patient with CSF leak, 1 patient with delayed facial nerve palsy, and 2 patients with asymptomatic sigmoid sinus occlusion, there were no other new morbidities. Although both observation and radiosurgery are valid options in the management of smaller size vestibular schwannomas, surgical treatment seems to offer a high rate of facial nerve preservation, a reasonable rate of hearing sparing, and a high total resection rate. Clinicians should consider surgical treatment as a valid option in the initial management of symptomatic small vestibular schwannomas in younger patients.

Introduction Petroclival meningiomas represent very uncommon and challenging tumors. Surgical morbidity is high due to the difficult and complex approaches to this area. In the present video presentation, we demonstrate a staged-approach surgical resection for petroclival meningioma. Patient and Methods A 47-year- old female was incidentally diagnosed with right sizable petroclival meningioma (Fig. 1). The decision to proceed with a staged approach was made based on size and extension of the tumor to both the middle and posterior fossa. At the first stage we performed a right anterior petrosectomy with the patient in the supine position and the head turned 45 degrees to the left. Residual tumor was left behind along its inferior pole. At the second stage, 2 weeks after the 1st surgery, a right retrosigmoid craniotomy was performed with the patient placed on left park-bench position and the residual tumor was removed. The patient tolerated both stages very well without significant neurological deficits except a transient diplopia after the first stge. Postoperative magnetic resonance imaging (MRI) revealed gross total resection of the tumor. Conclusion Staged approach for petroclival meningiomas represents a safe and effective surgical management, tolerable for the patient and more comfortable for the neurosurgeon.The link to the video can be found at: https://youtu.be/QJJchjAwD5c.

Objective Awake craniotomy for removal of intra-axial lesions is a well-established procedure. Few studies, however, have investigated the usefulness of this approach for resection of arteriovenous malformations adjacent to eloquent language areas. We demonstrate our experience by using cortical stimulation mapping and report for the first time on the usefulness of subcortical stimulation with interrogation of language function during resection of arteriovenous malformations (AVMs) located near language zones. Methods Patients undergoing awake craniotomy for AVMs located in language zones and at least 5 mm away from the closest functional magnetic resonance imaging activation were analyzed. During surgery, cortical bipolar stimulation at 50 Hz, with an intensity of 2 mA, increased to a maximum of 10 mA was performed in the region around the AVM before claiming it negative for language function. In positive language site, the area was restimulated 3 times to confirm the functional deficit. The AVM resection was started based on cortical mapping findings. Further subcortical stimulation performed in concert with speech interrogation by the neuropsychologist continued at key points throughout the resection as feasible. The usefulness of cortical and subcortical stimulation in addition to patient outcomes was analyzed. Results Between March 2009 and September 2014, 42 brain AVM resections were performed. Four patients with left-sided language zone AVMs underwent awake craniotomy. The AVM locations were fronto-opercular in 2 patients and posterior temporal in 2. The AVM Spetzler-Martin grades were II (2 patients) and III (2 patients). In 1 patient, complete speech arrest was noticed during mapping of the peri-malformation zone, which was not breached during resection. In a second patient who initially demonstrated negative cortical mapping, a speech deficit was noticed during resection and subcortical stimulation. This guided the approach to protect and avoid the sensitive zone. This patient experienced mild postoperative expressive dysphasia that improved to normal within 6 weeks. Complete resection was achieved in all 4 patients. There were no other complications and no permanent neurological morbidity, resulting in good outcome in all 4 patients. Conclusions Language mapping, both cortical and subcortical during AVM resection, may be valuable in a very select group of AVMs in language zones. Defining safe margins and feedback to the surgeon may provide the highest chances of a surgical cure while minimizing the risk of incurring a language deficit.

Background The endoscopic endonasal approach for pituitary neoplasms has shown similar efficacy compared with the microscopic approach. However, outcomes and complication rates with larger macroadenomas is not as well documented. This study addresses the efficacy and outcome of the fully endoscopic endonasal approach for large and giant pituitary adenomas. Methods Endoscopic endonasal resection was performed in 39 patients with large (>3 cm) or giant (>4 cm) pituitary macroadenomas. Outcomes were assessed using formal visual examinations, endocrine status, and neurologic examinations. Statistical analyses of multiple variables were addressed for correlation to visual, endocrine, and neurologic outcomes. Results Gross total resection of the pituitary macroadenoma was achieved in 22 of 39 (56.4%) patients based on postoperative magnetic resonance imaging. Higher Knosp grade was associated with near-total resection or subtotal resection ( P = 0.0004). All patients had improved or stable visual symptoms. Time to diagnosis, preoperative visual deficit, and tumor size were not significant predictors of visual outcome. Of patients, 34 (87.1%) had a "good" endocrine outcome, whereas 5 did not. Among the 5 patients who did not have a good outcome, 1 had new hypopituitarism, and 4 required increased dosages of pharmacologic therapy. All patients with recurrent tumors had stable visual and good endocrine outcomes. Postoperative cerebrospinal fluid leak occurred in 4 patients; lumbar drainage resolved the leak in 3, and reoperation was performed in 1 patient. There were no new cranial nerve deficits, new neurologic deficits, or mortality. Conclusions Endoscopic endonasal resection of large and giant pituitary macroadenomas is safe and efficient. Postoperative complications, including cerebrospinal fluid leak, are low. Surgical efficacy of the fully endoscopic endonasal approach for large and giant macroadenomas makes the technique a preferable option in this subset of patients.

The most common etiology of classic trigeminal neuralgia is vascular compression. However, other causes must be excluded. It is very unlikely that a meningocele presents with symptomatic trigeminal neuralgia. We present a rare case of a patient presenting with left trigeminal neuralgia. Thin-slice CT and MRI showed a transclival Meckel's cave meningocele. The patient underwent endoscopic repair of the meningocele, which resulted in complete resolution of her symptoms. Meckel's cave meningocele or encephalocele should be considered among the differential diagnoses of trigeminal neuralgia. Meningocele repair should be suggested as the first treatment option in this rare situation.

The potential utility of intraoperative microscope-integrated indocyanine green (ICG) fluorescence angiography in the surgery of brain arteriovenous malformations (AVMs) and evaluation of the completeness of resection is debatable. Postoperative catheter angiography is considered the gold standard. We evaluated the value of ICG and intraoperative catheter angiography in this setting. Between January 2009 and July 2013, 37 patients with brain AVMs underwent surgical resection of their vascular lesions. ICG videoangiography and an intraoperative catheter angiography were performed in 32 cases, and a routine postoperative angiogram was performed within 48 h to 2 weeks after surgery. The usefulness of ICG findings and the ability to confirm total resection and to identify residual nidus or persistent shunt were assessed and compared to intraoperative and postoperative digital subtraction angiography, respectively. There were 7 grade 1, 11 grade 2, 11 grade 3 and 3 grade 4 Spetzler-Martin classification AVMs. ICG angiography helped to distinguish AVM vessels in 26 patients. In 31 patients, it demonstrated that there was no residual shunting. In one patient, a residual AVM was identified and further resected. Intraoperative catheter angiography detected two additional small residuals that were missed by ICG angiography, both deep in the surgical cavity. Further resection of the AVM was performed, and total resection was confirmed by a repeat intraoperative angiogram. Postoperative angiography in a patient with a grade 4 lesion revealed one additional small deep residual AVM nidus with persistent late shunting missed on both ICG and intraoperative angiography. Overall ICG angiography missed three out of four residual AVMs after initial resection, while the intraoperative angiogram missed one. Although ICG angiography is a helpful adjunct in the surgery of some brain AVMs, it’s yield in detecting residual AVM nidus or shunt is low, especially for deep-seated lesions and higher grade AVMs. ICG angiography should not be used as a sole and/or reliable technique. High-resolution postoperative angiography must be performed in brain AVM surgery and remains the best test to confidently confirm complete AVM resection.

A 61-year-old male patient presented with recurrent malignant meningioma involving the left optic canal and decreased vision from the left eye. The patient had undergone orbital exenteration on the right 2 years ago. The decision to treat the patient was made based on the significant vision deterioration and rapid tumor growth. Endoscopic transsphenoidal approach considered the most suitable route due to the inferomedial invasion of the optic canal. Gross total removal was achieved and the patient's vision improved postoperatively. The patient developed hydrocephalus 4 weeks postoperatively and cerebrospinal fluid (CSF) leak. Ventriculoperitoneal shunt placement corrected both hydrocephalus and CSF leak.The link to the video can be found at: https://youtu.be/2cOF0pf5gAk.

BACKGROUND The role of expanded endonasal endoscopic surgery for primary and recurrent craniopharyngioma is not yet fully established. OBJECTIVE To report and evaluate our experience with the endoscopic endonasal approach (EEA) for the resection of primary and recurrent craniopharyngiomas. METHODS This is a retrospective cohort analysis of 43 consecutive EEA procedures in 40 patients operated from September 2006 to February 2012 for suprasellar craniopharyngiomas. In 21 patients (48.8%) the disease was recurrent. We have assessed the surgical results, visual, endocrinological, and functional outcomes and resection rates in this patient cohort. RESULTS At presentation, 31 (72.1%) patients had visual deficits, 15 patients (34.9%) complained of headaches, 25 patients (58.1%) had anterior pituitary insufficiency, and 14 (32.5%) had diabetes insipidus. Total resection was achieved in 44.2% surgeries, of which 77.3% were in primary lesions and 9.5% in recurrent lesions (P

Particular care to facial nerve function preservation should be the ultimate goal in surgery for large vestibular schwannomas. We present a 60-year-old patient who presented with an enlarging right vestibular schwannoma and nonserviceable hearing. The patient was operated in the semisitting position after a patent foramen ovale was ruled out. During the positioning, the feet were positioned at the level of the heart. Precordial Doppler was used to monitor for air embolism. Straight skin incision and retrosigmoid craniotomy was performed. Specific attention to venous bleeding was made during the approach. Meticulous arachnoid dissection of the capsule preserving the arachnoid plane at the surface of the brain stem and the facial nerve can be achieved more efficiently with the patient in the semisiting position and with bimanual microdissection technique. After drilling of the internal auditory canal (IAC), we were able to achieve near total removal of the tumor, leaving a tiny tumor carpet due to extreme adherence to the nerve. Water-tight dura closure and replacement of the bone flap was performed. The patient woke up with a House–Brackmann grade III facial weakness which improved to grade I at 6 weeks postoperatively. Postoperative magnetic resonance imaging (MRI) showed a tiny residual at the surface of the facial nerve at the entrance of the IAC. Near total (> 98%) resection of large vestibular schwannomas is an acceptable surgical strategy with excellent facial nerve outcome. With appropriate patient positioning in semisitting and proper anesthesiological and surgical management, the risk of air embolism is negligible.The link to video can be found at: https://youtu.be/ErG9VexbiGw.

Tuberculum sella meningioma can be approached by either open or endoscopic approaches. The aim of this video case presentation is to highlight the nuances of the lateral supraorbital craniotomy for tuberculum sella meningioma resection. The authors present a 34-year-old female patient who presented with decreased right eye visual acuity (20/60), afferent pupillary defect, and nasal field cut due to a tuberculum sella meningioma. The tumor was partially encasing the left A1 artery, severely displacing the optic apparatus, and minimally invading the right optic canal. The lateral supraorbital craniotomy was considered the most suitable approach to this tumor. The operative nuances and pitfalls of this approach are detailed in the video. Gross total resection of the tumor was achieved and confirmed with postoperative MRI. The patient's vision gradually improved and she was discharged on the fourth postoperative day. The minimally invasive lateral supraorbital craniotomy for tuberculum sella meningioma is a suitable approach in selected cases.The link to the video can be found at: https://youtu.be/yG8q6YH2D9k.

A 64-year-old man with a midbrain cavernoma and prior bleeding presented with a 1-week history of diplopia, partial left oculomotor nerve palsy, and worsening dysmetria and right-sided weakness. MRI revealed a hemorrhagic left tectal plate and midbrain cavernoma. A left suboccipital supracerebellar transtentorial approach in the sitting position was performed for resection of his lesion utilizing the lateral mesencephalic sulcus safe entry zone. Postoperatively, he developed a partial right oculomotor nerve palsy; imaging depicted complete resection of the cavernoma. He recovered from the right third nerve palsy, weakness, and dysmetria, with significant improvement of his partial left third nerve palsy.The video can be found here: https://youtu.be/ofj8zFWNUGU.

Posterior fossa dural arteriovenous fistulas are rare vascular malformations. If associated with cortical venous reflux, they present a significant risk of hemorrhage. We present a 54-year-old male who presented with progressive hearing loss without other neurologic symptoms. Further workup revealed tentorial incisura dural arteriovenous fistula with cortical venous reflux and aneurysmal dilation of venous drainage (type IV Cognard), fed from the right internal carotid artery and external carotid artery. After multidisciplinary discussion, we decided on surgical disconnection of the fistula as we felt this approach would have the highest chance of immediate and durable cure. We performed a right retrosigmoid craniotomy with (Video 1) disconnection of the arterialized veins and thus achieved completed obliteration. Follow-up angiography 8 months later showed no evidence of residual/recurrent fistula. The patient's hearing improved. There were no adverse effects during the perioperative period.

Posterior fossa dural arteriovenous fistulas (dAVFs) are rare vascular malformations. They carry a significant risk of hemorrhage if associated with cortical venous reflux. A 70-year-old man presented with right-sided medullary hemorrhage with pronounced Wallenberg syndrome. Angiography demonstrated right jugular foramen dAVF with direct brainstem venous reflux (Cognard IV). It was fed from multiple branches of the external carotid artery and the vertebral artery, and draining into the ascending pontomesencephalic vein. Primary two-stage transarterial embolization was performed with near-total occlusion of the fistula to prevent it from rebleeding in the acute phase. Because of the patient’s significant neurological deficit, the surgery was deferred to later and if the DAVF showed further progression. Follow-up angiography 8 months later demonstrated obvious recurrence and progression of the fistula from adjacent feeders. In the meantime, the patient had a remarkable recovery from the Wallenberg symptoms. To achieve complete occlusion of the fistula, a right far lateral approach was chosen with complete disconnection of the fistula. Postoperative angiography confirmed complete occlusion of the fistula, and the patient remained intact from the procedure.The video can be found here: https://youtu.be/DJvpa8G4olc.

The orbitozygomatic craniotomy has been developed and modified over the last three decades, and has become a quintessential approach and technique for the well-rounded neurosurgeon. In this paper, we describe the technique as well as numerous modifications developed in order to suit the various pathologies in the anterior and middle cranial fossae.

Having absolute hemostasis is crucial in skull base surgery, because bleeding decreases visualization and increases the risk of postoperative complications. Achieving hemostasis starts from the preoperative evaluation. A thorough clinical history and routine tests guide the surgeon to minimize bleeding risk preoperatively, and comprehensive study of preoperative images helps the surgeon to predict bleeding risk and to consider preoperative embolization in suitable cases. Many hemostatic agents are available to control intraoperative bleeding; understanding of their indications and properties is crucial to achieve hemostasis. Whether endoscopic or transcranial approach, microsurgical techniques to avoid and control bleeding are the same.

Background For some posterior inferior cerebellar artery (PICA) aneurysms, there is no constructive endovascular or direct surgical clipping option. Intracranial bypass is an alternative to a deconstructive technique. Objective To evaluate the clinical features, surgical techniques, and outcome of PICA aneurysms treated with bypass and obliteration of the diseased segment. Methods Retrospective review of PICA aneurysms treated via intracranial bypass was performed. Outcome measurements included postoperative stroke, cranial nerve deficits, gastrostomy/tracheostomy requirement, bypass patency, modified Rankin scale (mRS) at discharge, and mRS at 6 mo. Results Seven patients with PICA aneurysms treated with intracranial bypass were identified. Five had fusiform aneurysms (4 ruptured, 1 unruptured), 1 had a giant partially thrombosed saccular aneurysm (unruptured), and 1 had a dissecting traumatic aneurysm (ruptured). Two aneurysms were at the anteromedullary segment, 4 at the lateral medullary segment, and 1 at the tonsillomedullary segment. Three patients underwent PICA-to-PICA side to side anastomoses, 2 PICA-to-PICA reanastomosis, 1 vertebral artery-to-PICA bypass, and 1 occipital artery-PICA bypass. Six out of 7 aneurysms were obliterated surgically and 1 with additional endovascular occlusion after the bypass. All bypasses were patent intraoperatively; 2 were later demonstrated occluded without radiological signs or symptoms of stroke. No patients had new cranial nerve deficit postoperatively. With the exception of 1 death due to pulmonary emboli 3 mo postoperatively, all others remain at a mRS ≤ 2. Conclusion Constructive bypass and aneurysm obliteration remains a viable alternative for treatment of PICA aneurysms not amenable to direct surgical clipping or to a vessel-preserving endovascular option.

Transsphenoidal selective adenectomy is considered the treatment of choice in patients with Cushing’s disease given the possibility for high remission and low complication rates. The endoscopic endonasal surgical nuances for Cushing’s disease are not well illustrated in the neurosurgical technique and video collections. We describe the technical nuances of microadenoma resection for two cases of Cushing’s disease, one in which the adenoma is visualized on imaging and one in which the pre-operative MRI is negative. Transsphenoidal endoscopic selective adenectomy is a safe and effective surgery for patients with Cushing’s disease regardless of preoperative MRI findings.