Which is a more appropriate recipient for posterior circulation bypass surgery: V3 or V2? Differences in underlying disease and lesion sites between extracranial vertebral artery dissection and atherosclerotic changes. Illustrative cases.

BACKGROUND: Revascularization for extracranial vertebral artery dissection or vertebral artery atherosclerotic occlusive lesions caused by vertebrobasilar insufficiency or posterior circulation infarction is relatively rare. When bypassing the cervical external carotid artery (ECA) or common carotid artery (CCA) using a radial artery (RA) or saphenous vein (SV) graft, it is difficult to determine whether the recipient site should be the V2 or V3 portion. OBSERVATIONS: In case 1, cervical ECA-RA-V3 bypass was performed for bilateral extracranial vertebral artery dissection with the onset of ischemia, and cervical CCA-SV-V3 bypass was added 12 days later. Nine years after surgery, the bilateral vertebral artery dissection had improved, and the patient still had a patent bypass. In case 2, cervical ECA-RA-V2 bypass was performed for arteriosclerotic bilateral extracranial vertebral artery occlusion. The bypass was patent 5 years after surgery. The postoperative course was uneventful in both patients. LESSONS: The authors present cases of posterior fossa revascularization using the vertebral artery V3 and V2 portions via skull base surgery and note that it is important to consider each patient's individual characteristics when selecting the V3 or V2 portion.

Extensive extracranial growth of spheno-orbital meningioma: illustrative case.

BACKGROUND: Spheno-orbital meningioma (SOM) typically presents with a classic triad of symptoms (i.e., proptosis, visual impairment, and ocular paresis), resulting from intraorbital tumor invasion. The authors present a very rare case of SOM in which the chief complaint was swelling of the left temporal region, which, to the best of their knowledge, has not been reported previously. OBSERVATIONS: The patient presented with marked extracranial extension to the left temporal region but unremarkable intraorbital extension, even on radiological examination. Physical examination of the patient showed almost no exophthalmos or restriction of left eye movement, consistent with the radiological findings. Four separate meningioma specimens were removed by extraction (i.e., one each from the intracranial, extracranial, and intraorbital segments of the tumor and one from the skull). The World Health Organization grade was 1 and the MIB-1 index was less than 1%, indicating a diagnosis of a benign tumor. LESSONS: SOM may be present even in patients with only temporal swelling and few ocular-related symptoms, and detailed imaging evaluations may be required to identify the tumor.

Microvascular Decompression for Glossopharyngeal Neuralgia in the Semi-Sitting Position: A Report of Two Cases.

The semi-sitting position is well known to neurosurgeons. However, there are few reports of microvascular decompression surgery for glossopharyngeal neuralgia performed using the semi-sitting position. The semi-sitting position is not widely adopted in Japan, but it is considered to be a very useful neurosurgical position. Microvascular decompression surgery for glossopharyngeal neuralgia is a relatively rare procedure, and the semi-sitting position is very effective, considering the possibility of intraoperative cardiac arrest and postoperative complications of lower cranial nerve palsy. This report describes two cases of glossopharyngeal neuralgia operated in the semi-sitting position. Microvascular decompression was performed on both patients, and postoperative pain controls were good and no complications were observed. We show that the use of the semi-sitting position to perform microvascular decompression for glossopharyngeal neuralgia provides an excellent surgical view of the brainstem.

A Rare Case of Intracerebral Pneumocephalus Caused by Preexisting Multiple Bone Defects and Encephalocele after Resection of Meningioma.

Pneumocephalus is generally secondary to direct damage to the skull base. Spontaneous intracerebral pneumatocele without head injury was extremely rare, but previously reported as a serious complication of shunt procedures. We describe a 40-year-old man with intracerebral pneumocephalus who previously underwent craniotomy for large frontal convexity meningioma and lumbo-peritoneal shunting. He presented with gait disturbance 14 months after tumor resection. Computed tomography and magnetic resonance imaging showed intracerebral pneumocephalus in the right temporal lobe, which continued into the mastoid air cells through a bone defect of the right petrous bone. We performed urgent right temporal craniotomy to reduce the mass effect and to repair the fistula. Intraoperatively, bone defects were identified at the roof petrous bone, into which the encephalocele had penetrated. The herniated cerebral parenchyma was removed, and the pneumocephalus opened. The dura was closed with sutures and covered with fascia. To elucidate the underlying mechanism for the development of intracranial pneumocephalus, the previous images obtained before or immediately after resection of meningioma were reviewed. We founded that multiple preexisting bone defects and encephaloceles, one of which was considered to be the cause of the intracerebral pneumocephalus. This case demonstrates that intracerebral pneumocephalus can be caused by preexisting bone defect and encephalocele, and this finding may be useful for prediction of pneumocephalus after shunt procedures.

Estimation of the head elevation angle that causes clinically important venous air embolism in a semi-sitting position for neurosurgery: a retrospective observational study.

INTRODUCTION: The benefits of a sitting position for neurosurgery involving the posterior fossa remain controversial. The main concern is the risk of venous air embolism (VAE). A recent study showed that the rate of VAE was higher when the head was elevated to 45° than when it was elevated to 30°. However, the degree of head elevation that causes clinically important VAE is unclear. The purpose of this study was to estimate the head elevation angle at which the probability of VAE is 50% by using EtCO2 monitoring to detect of VAE. METHODS: The anesthesia records of 23 patients who underwent neurosurgery in a sitting position were reviewed retrospectively. Intraoperative ventilation was set to maintain EtCO2 at approximately 38-42 mmHg. The head elevation angle in each case was determined from a photograph taken by the anesthesiologist or brain surgeon. Nineteen of the 23 cases had photographs available that contained a horizontal reference in the background. Seven cases were treated as VAE during the operation. Six of these cases met the criteria for VAE in this study. Data analysis was performed on a total of 18 patients. The angle between the line connecting the hip joint and the shoulder joint and the horizontal reference was obtained by ImageJ software. Logistic regression was performed using the Python programming language to determine the head elevation angle at which the probability of air embolism was 50%. RESULTS: The decision boundary in the logistic regression was 35.7°. This head elevation angle was the boundary where the probability of VAE was 50%. CONCLUSION: The angle of head elevation that caused clinically important VAE was estimated to be 35.7°.

Limitations of median nerve somatosensory evoked potential monitoring during carotid endarterectomy.

OBJECTIVE: Hypoperfusion during carotid artery cross-clamping (CC) for carotid endarterectomy (CEA) may result in the major complication of perioperative stroke. Median nerve somatosensory evoked potential (MNSSEP) monitoring, which is an established method for the prediction of cerebral ischemia, has low sensitivity in detecting such hypoperfusion. In this study the authors sought to explore the limitations of MNSSEP monitoring compared to tibial nerve somatosensory evoked potential (TNSSEP) monitoring for the detection of CC-related hypoperfusion. METHODS: The authors retrospectively analyzed data from patients who underwent unilateral CEA with routine shunt use. All patients underwent preoperative magnetic resonance angiography and were monitored for intraoperative cerebral ischemia by using MNSSEP, TNSSEP, and carotid stump pressure during CC. First, the frequency of MNSSEP and TNSSEP changes during CC were analyzed. Subsequently, variables related to stump pressure were determined by using linear analysis and those related to each of the somatosensory evoked potential (SSEP) changes were determined by using logistic regression analysis. RESULTS: A total of 94 patients (mean age 74 years) were included in the study. TNSSEP identified a greater number of SSEP changes during CC than MNSSEP (20.2% vs 11.7%; p < 0.05). Linear regression analysis demonstrated that hypoplasia of the contralateral proximal segment of the anterior cerebral artery (A1 hypoplasia) (p < 0.01) and hypoplasia of the ipsilateral precommunicating segment of the posterior cerebral artery (P1 hypoplasia) (p = 0.02) independently and negatively correlated with stump pressure. Both contralateral A1 hypoplasia (OR 26.25, 95% CI 4.52-152.51) and ipsilateral P1 hypoplasia (OR 8.75, 95% CI 1.83-41.94) were independently related to the TNSSEP changes. However, only ipsilateral P1 hypoplasia (OR 8.76, 95% CI 1.61-47.67) was independently related to MNSSEP changes. CONCLUSIONS: TNSSEP monitoring appears to be superior to MNSSEP in detecting CC-related hypoperfusion. Correlation with stump pressure and SSEP changes indicates that TNSSEP, and not MNSSEP monitoring, is a reliable indicator of cerebral ischemia in the territory of the anterior cerebral artery.

Clinical features of subarachnoid hemorrhage in patients with positive cancer history.

Advances in cancer treatment have dramatically increased long-term survivors. Prolonged survival increases comorbidity risk, but there is a paucity of studies on how cancer history alters clinical outcomes from subsequent diseases. This study aims to investigate whether positive cancer history influences clinical outcome following subarachnoid hemorrhage (SAH). We retrospectively reviewed consecutive SAH patients admitted between January 2008 and March 2014. Medical histories, known SAH risk factors, and outcome were compared between SAH patients with and without cancer history. Out of the 498 SAH patients, 55 cases had cancer history, 438 cases had no cancer history and 5 cases had an unknown cancer history. Compared with SAH patients without cancer history, those with cancer history had poorer Hunt & Hess grade at SAH presentation (P = 0.021), and poorer modified Rankin Scale (mRS) score at discharge (P < 0.001). After adjustment for age, sex, modified Fisher, previous SAH, history of hypertension, current smoking status, and current alcohol consumption, positive cancer history remained an independent risk factor for poorer mRS0-6 [odds ratio (OR) = 2.25, 95 % confidence interval (CI) 1.28-3.94] and mRS6 (OR = 2.74, 95 % CI 1.40-5.37). Furthermore, stratified analysis by Hunt & Hess grade adjusted by age, sex, and modified Fisher scale, OR of poorer mRS0-6 was 2.12 (95 % CI 0.89-5.05) and OR of mRS6 was 3.68 (95 % CI 1.35-10.04). After adjustment of patients for demographic factors, classical risk factors for SAH and Hunt & Hess grade, previous cancer history is a risk factor for the poor functional outcome of SAH.

A case of difficult management of fluid-electrolyte imbalance in choroid plexus papilloma.

A 22-month-old boy presented with nausea and gradual deterioration of gait disturbance. Computed tomography (CT) demonstrated an intraventricular mass lesion in the right lateral ventricle. He was referred to our department 3 weeks after onset. Acute hydrocephalus gradually proceeded 4 days after admission, and external ventricular drainage (EVD) was performed. EVD revealed cerebrospinal fluid (CSF) overproduction (800-1,500 mL/day) under constant pressure of 10 cm H2O above external auditory meatus. Magnetic resonance imaging showed a multi-lobular mass in the inferior horn of the right lateral ventricle. A choroid plexus tumor was suspected. The ratio of blood urea nitrogen:creatinine (BUN:Cre) remained between 30 and 40, and hemoglobin was between 14.0-17.0 mg/dL, suggesting marked dehydration. Serum sodium varied between 117 and 140 mmol/L, and serum potassium between 2.2 mmol/L and 6.9 mmol/L. The amount of EVD was unstable and fluid balance management was difficult. Hypotonic fluid with sodium chloride supplement was used to adjust the fluid and electrolyte imbalance. Surgical removal of the tumor was performed 6 days after EVD and tumor was grossly and totally removed. The high BUN:Cre ratio decreased to about 15 and hemoglobin recovered to 7.5-9.0 mg/dL after removal. Electrolytes returned to the normal range. Overproduction of CSF also markedly improved to < 300 mL/day. Histopathological examination diagnosed choroid plexus papilloma.We experienced a case of choroid plexus papilloma associated with fluid-electrolyte imbalance due to over-drainage after EVD, which could not be effectively controlled before tumor removal. Cautious fluid management and emergent surgical resection might be required to manage the overproduction of CSF and fluid-electrolyte imbalance.

Subarachnoid hemorrhage after an ischemic attack due to a bacterial middle cerebral artery dissecting aneurysm: case report and literature review.

A 78-year-old woman suffered sudden-onset left hemiparesis. There were no remarkable infectious findings. Computed tomography (CT) demonstrated a low-intensity area supplied by the right middle cerebral artery (MCA). The diagnosis was cerebral ischemia and she was conservatively treated with hyperosmotic fluids. Two days after the ischemic stroke she suddenly became comatose. CT showed diffuse subarachnoid hemorrhage (SAH) in the basal cistern associated with a right intra-Sylvian and a right frontal subcortical hematoma. Three-dimensional (3D)-CT angiography demonstrated occlusion of the M2 portion of the right MCA. Four days after the ischemic onset she died of brain herniation. Autopsy revealed arterial dissection in the intermediate membrane of the right MCA bifurcation and occlusion of the M2 portion of the thrombosed right MCA. Gram staining showed remarkable bacterial infection in the thrombus. SAH after an ischemic attack due to MCA dissection is extremely rare. We suspect that bacterial infection was involved in the formation of her fragile dissecting aneurysm.

Distinctive flow pattern of wall shear stress and oscillatory shear index: similarity and dissimilarity in ruptured and unruptured cerebral aneurysm blebs.

OBJECT: The difference in the hemodynamics of wall shear stress (WSS) and oscillatory shear index (OSI) between ruptured and unruptured aneurysms is not well understood. The authors investigated the hemodynamic similarities and dissimilarities in ruptured and thin-walled unruptured aneurysm blebs. METHODS: Magnetic resonance imaging-based fluid dynamics analysis was used to calculate WSS and OSI, and hemodynamic and intraoperative findings were compared. The authors also compared ruptured and unruptured thin-walled blebs for the magnitude of WSS and OSI. RESULTS: Intraoperatively, 13 ruptured and 139 thin-walled unruptured aneurysm blebs were identified. Twelve of the ruptured (92.3%) and 124 of the unruptured blebs (89.2%) manifested low WSS and high OSI. The degree of WSS was significantly lower in ruptured (0.49 ± 0.12 Pa) than in unruptured (0.64 ± 0.15 Pa; p < 0.01) blebs. CONCLUSIONS: Ruptured and unruptured blebs shared a distinctive pattern of low WSS and high OSI. The degree of WSS at the rupture site was significantly lower than in the unruptured thin-walled blebs.

Subependymoma in the lateral ventricle manifesting as intraventricular hemorrhage.

A 32-year-old man presented with subependymoma in the lateral ventricle causing intraventricular hemorrhage and manifesting as severe headache and disturbance of consciousness. Computed tomography on admission showed a massive intraventricular hemorrhage and acute obstructive hydrocephalus. Cerebral angiography revealed no abnormal findings. Emergency external ventricular drainage was performed, and his neurological deficits gradually improved. Magnetic resonance imaging at 5 weeks after admission showed a tumor arising from the septum pellucidum or the floor of the right lateral ventricle, appearing as a mixed-intensity solid tumor, which was partially enhanced following gadolinium administration. The tumor had arisen from the septum pellucidum and was totally removed via an interhemispheric anterior transcallosal approach. Histological examination found typical subependymoma, with little vascularity. Intraventricular hemorrhage from cerebral neoplasms is usually due to highly vascular tumors. Since subependymomas are quite benign and show poor vascularity, intraventricular or subarachnoid hemorrhages are very rare, but do occasionally occur.

Anterior cranial fossa dural arteriovenous fistula with bilateral cortical drainers--case report.

A 58-year-old man presented with sudden onset of severe headache. Computed tomography demonstrated subarachnoid hemorrhage and right acute subdural hematoma. He had no neurological deficits. Cerebral angiography showed an anterior cranial fossa dural arteriovenous fistula (AVF) supplied by the bilateral ethmoidal arteries. A fistula was suggested on the right side, and the dural AVF drained into the superior sagittal sinus via the bilateral frontal cortical veins. Venous varix was observed at both drainage sites. Bifrontal craniotomy with right-side dural incision was performed and the fistula was interrupted. Postoperative angiography demonstrated a persistent fistula draining into the left cortical vein. Nineteen days later, bifrontal craniotomy with left-side dural incision was performed and the draining vein was completely coagulated with the aid of intraoperative angiography. Postoperatively, there was no detectable residual fistula. He was discharged without neurological deficits 2 weeks after surgery. The present case of anterior cranial fossa dural AVF with bilateral cortical drainers shows that drainer occlusion at two points may be needed for complete obliteration of the drainers because the fistulous connection may not be simple.

[A case of symptomatic arachnoid cyst, that had been growing for 14 years, at the posterior part of the left temporal lobe].

The authors report a 54-year-old woman with headache in whom a cyst was detected at the posterior part of the left temporal lobe following a traffic accident in 1993. Symptoms had recently worsened and computed tomography demonstrated an enlarged cyst in 2007. Thereafter, the patient underwent cyst fenestration. Intraoperative findings showed multilocular cysts with calcification. Symptoms improved immediately. Histological findings showed that the cyst was composed of collagenous membrane and a monolayer of cells compatible with arachnoid cyst. These findings also showed calcification and we considered that growth of the arachnoid cyst had been induced by trauma. We expected an arachnoid cyst with a single cavity, but this lesion was multilocular. Retrospectively, cine magnetic resonance image (MRI) seemed to show multilocular cysts. Cine MRI might be an effective tool to determine whether a cyst is multilocular.

Cavernous angioma associated with arteriovenous malformation of the brain--case report.

A 61-year-old man presented a rare case of cerebral cavernous angioma associated with cerebral arteriovenous malformation (AVM) manifesting as headache. Magnetic resonance imaging showed an AVM in the right occipital lobe and a cavernous angioma in the left middle fossa. The patient underwent left frontotemporal craniotomy with total resection of the left parasellar intra-axial tumor. One month after the first operation, he underwent right occipital craniotomy with total resection of the right occipital AVM. The histological diagnoses were cavernous angioma and AVM, respectively. Immunostaining for angiogenic growth factors and structural proteins revealed different expression patterns of alpha-smooth muscle actin in these structures. Expression of structural proteins may reflect differences in their pathogenesis.

Efficacy of middle meningeal artery embolization in the treatment of refractory chronic subdural hematoma.

BACKGROUND: There are no established treatment procedures for repeatedly recurring chronic subdural hematoma (CSH). In this study, we discussed the efficacy of middle meningeal artery (MMA) embolization in preventing recurrence of CSH. METHODS: We performed superselective angiography of MMA in four patients who suffered from repeated recurrence of CSH. After angiography, we performed embolization of MMA with endovascular procedure. RESULTS: In all cases, superselective angiography of MMA revealed diffuse abnormal vascular stains that seemed to represent the macrocapillaries in the outer membrane of CSH. In all the patients, there were no recurrences or enlargements of CSH after the embolization of the MMA. CONCLUSION: MMA embolization can be an effective adjuvant procedure in preventing the recurrence of CSH.

Serial angiography of dynamic changes of traumatic middle meningeal arteriovenous fistula: case report.

A 48-year-old woman suffered head trauma and presented with an acute epidural hematoma with a linear fracture of the right temporal bone across the middle meningeal groove. Initial angiography demonstrated no vascular abnormalities. Eight months later, she again suffered head trauma and computed tomography demonstrated traumatic subarachnoid hemorrhage. Right external carotid angiography revealed a middle meningeal arteriovenous fistula (AVF) which drained into the superficial sylvian veins via the sphenoparietal sinus. Serial angiography showed progressive dilation of the draining veins, but she refused surgical intervention and dropped out of our outpatient clinic. Fifteen years after the first head trauma, she presented with subarachnoid hemorrhage. Angiography demonstrated formation of venous aneurysms on the drainer of the AVF. The dilated superficial sylvian vein was removed together with the ruptured venous aneurysm. Histological examination of the drainer revealed an arterialized vein. The serial angiographic evaluations revealed dynamic changes of the traumatic middle meningeal AVF, including progressive dilation of the drainers, simplification of the drainage routes, and the formation of venous aneurysms, which presumably represents the entire natural course of traumatic middle meningeal AVF manifesting as hemorrhage. The present case of traumatic middle meningeal AVF with a deteriorating course suggests that surgical removal or embolization of the AVF is strongly indicated if follow-up angiography shows dilation of the drainers, which implies increased shunt flow.

[A case of posttraumatic forehead cavernous angioma].

Cavernous angiomas of the bone are rare tumors. Skull cavernomas are even less frequent. Most cavernous angiomas of the bone are congenital tumors. In a review of the literature, we found only one case report of de novo generation of a skull cavernous angioma. We present a case of a 25-year-old woman who had experienced a head injury, and 7 years later exhibited a skull tumor at the exact region of the injury. We performed tumor resection and cranioplasty. Follow-up examinations revealed no recurrence or neurological defects. Pathological findings showed a cavernous angioma-like lesion with some atypical details. We finally diagnosed the lesion as a de novo cavernous angioma. Our case suggests that fine injury may result in de novo generation of bone cavernomas.

[Choice of intentional partial coiling for a ruptured intracranial aneurysm in the acute stage followed by clipping in the chronic stage].

The inpact of the International Subarachnoid Aneurysm Trial (ISAT) trial publication in 2002 and major technical advances in neuroimaging, endovascular devices and techniques have resulted in increasing numbers of patients with ruptured aneurysms undergoing endovascular coiling, as first-line treatment for aneurysm occlusion. We treated six cases of ruptured aneurysms with this strategy, with choice of clipping as as additional treatment following intentional partial coiling. In this series, patients ranged in age from 36 to 74 years and included one man and five women. Three aneurysms were located in AcomA, 1 in ACA, and 2 in MCA. The reasons for the choice of this strategy were clinical and angiographical spasm in 2, high general surgical risk in 2, and other reasons in 2 cases, respectively. The mean interval between the first partial coiling and final clipping was 33 days. All cases were successfully clipped without difficulties and coil removal were performed in 3 cases for follow up examination. It is proposed that the choice of this strategy contributes to progresses in overall outcomes in cases of aneurysmal subarachnoid hemorrhage.