Estimation of the rupture point of the craniovertebral junction intradural arteriovenous fistula with vessel wall magnetic resonance image and its pathological findings: A case report.

Background: Arteriovenous fistulas (AVFs) of the craniocervical junction (CCJ) and intradural AVFs are often associated with aneurysms and varics, and it is sometimes difficult to identify the ruptured point on radiological images. We report a case in which vessel wall magnetic resonance image (VW-MRI) was useful for identifying the ruptured point at the CCJ AVF. Case Description: A 70-year-old man presented with a sudden onset of headache. He had Glasgow Coma Scale E4V5M6, world federation of neurosurgical societies (WFNS) Grade I. Fisher group 3 subarachnoid hemorrhage and hydrocephalus were found on head computed tomography. Cerebral angiography showed a spinal AVF at the C1 level of the cervical spine. Magnetic resonance image-enhanced motion sensitized driven equilibrium (MSDE-method showed an enhancing effect in part of the AVF draining vein, but the vascular architecture of this lesion was indeterminate. We performed continuous ventricular drainage for acute hydrocephalus and antihypertensive treatment. Cerebral angiography was performed 30days after the onset of the disease, and was revealed an aneurysmal structure in a portion of the AVF draining vein, which VW-MRI initially enhanced. On the 38th day after onset, he underwent direct surgery to occlude the AV fistula and dissect the aneurysmal structure. Histopathology showed that the aneurysmal structure was varices with lymphocytic infiltration, and hemosiderin deposition was observed near the varices. Conclusion: Recently, VW-MRI has been reported to show an association between the enhancement of varices in dural AVF and rupture cases. VW-MRI, especially the enhanced MSDE method, may be useful in estimating the ruptured point in arteriovenous shunt disease.

Intracranial parenchymal capillary hemangioma: A case report.

Background: Capillary hemangioma is a rare benign hemangioma that occurs in the soft tissues of the skin, orbit, head, and neck. Intracranial cases, especially intraparenchymal cases, are extremely rare. In this study, we report the course of an intracranial parenchymal capillary hemangioma with left mild motor paresis and involuntary movements of the left upper extremity and was successfully treated by surgical resection, including radiological and pathological examinations. Case Description: This is a case of a 60-year-old woman who presented with motor weakness and involuntary movement of the left upper extremity. Computed tomography and magnetic resonance imaging revealed the right frontal hemorrhagic mass lesion without enhancement of contrast medium. Cerebral digital subtraction angiography showed no vascular stain and abnormal arteriovenous shunt. Preoperatively, we diagnosed cavernous hemangioma with a hemorrhagic component located in the right motor cortex. Because this case was symptomatic, we performed a craniotomy and gross total resection of the right frontal lesion. The diagnosis of capillary hemangioma was made by histological examination, including immunohistological study. Conclusion: Because intraparenchymal capillary hemangiomas are difficult to diagnose with preoperative imaging, surgical treatment, and histopathological examination are important.

Late-onset aqueductal membranous occlusion treated neuroendoscopic procedure and consideration of its pathological findings: A case report.

Background: Aqueduct of Sylvius stenosis/obstruction interferes with cerebrospinal fluid (CSF) flow and leads to the non-communicating hydrocephalus. Acquired non-neoplastic causes of aqueduct of Sylvius stenosis/ obstruction include simple stenosis, gliosis, slit-like stenosis, and septal formation, but the detailed mechanisms are not clear. In the present study, we experienced a case of late-onset aqueductal membranous occlusion (LAMO) successfully treated by neuroendoscopic procedure, which allowed us to examine the pathology of the membranous structures of the aqueduct of Sylvius occlusion. Case Description: A 66-year-old woman presented with gradually progressive gait disturbance, cognitive dysfunction, and urinary incontinenc. Brain magnetic resonance imaging (MRI) showed enlargement of the bilateral lateral ventricles and the third ventricle without dilatation of fourth ventricle, and heavily T2-weighted images showed an enlarged aqueduct of Sylvius and a membranous structure at its caudal end. Gadolinium contrast-enhanced T1-weighted images showed no neoplastic lesions. We diagnosed this case that the hydrocephalus due to late-onset idiopathic aqueductal stenosis or LAMO and the patient underwent endoscopic third ventriculostomy and endoscopic aqueduct oplasty. Membranous tissue specimens were obtained from the occluded aqueduct of Sylvius at the time of treatment. Histopathological examination revealed gliosis, and inside the gliosis, there were cell clusters that appeared to be ependymal cells and were corpora amylacea. We confirmed CSF flow at the site of obstruction of the aqueduct of Sylvius and the stoma of the third ventricle floor by MRI images. Her symptoms were improved immediately. Conclusion: We experienced a case of LAMO successfully treated by neuroendoscopic procedure, which allowed us to examine the pathology of the membranous structure of the aqueduct of Sylvius. The pathological study of LAMO is rare, and we report it, including a review of the literature.

Postpartum reversible cerebral vasoconstriction with cortical subarachnoid hemorrhage and posterior reversible encephalopathy syndrome concomitant with vertebral artery dissection diagnosed by MRI MSDE method: A case report and review of literature.

Headache is one of the most common symptoms encountered during the postpartum period. The cause may be unknown, or the following illnesses are possible: cervical artery dissection (CAD), reversible posterior cerebral encephalopathy syndrome (PRES), and reversible cerebral vasoconstrictor syndrome (RCVS). It is suggested that they are interrelated and share a similar mechanism such as small vessel endothelial dysfunction, deficiencies in self-regulation, and decreased sympathetic innervation of the posterior circulation. However, there are few reports of neuroradiological findings. We experienced a rare case of multiple postpartum vascular disease occurring at the same time. A 38-year-old woman suddenly developed thunderclap headache after giving birth. She was clear and had no neuropathy. Computed tomography revealed subarachnoid hemorrhage, including the cortical surface of the frontal lobe. Magnetic resonance image fluid-attenuated inversion recovery revealed high-intensity area in the bilateral basal ganglia and right occipital cortex. Angiography showed "string sausage" and extracranial left vertebral artery stenosis, but no aneurysm. Based on the clinical course and neuroradiological findings, we diagnosed her as postpartum vascular disease including CAD, PRES, RCVS, and cortical subarachnoid hemorrhage (SAH). Three-dimensional black blood T1-weighted images using a motion-sensitized driven equilibrium three-dimensional turbo spin echo (MSDE) sequencing method revealed an intramural hematoma consistent with the extracranial vertebral artery. After 3 months, MSDE lost its abnormal signal. Our case was rare in that multiple phenomena of postpartum vascular disease occurred at the same time. In particular, we could reveal that this speculation was reversible in the MRI MSDE sequencing.

Ingenuity using 3D-MRI fusion image in evaluation before and after microvascular decompression for hemifacial spasm.

Background: Hemifacial spasm (HFS) is most often caused by blood vessels touching a facial nerve. In particular, responsible vessels compress the root exit zone (REZ) of the facial nerve. Although we recognize these causes of HFS, it is difficult to evaluate the findings of precise lesion in radiological imaging when vessels compress REZ. Hence, we tried to obtain precise images of pre- and postoperative neuroradiological findings of HFS by creating a fusion image of MR angiography and the REZ of facial nerve extracted by magnetic resonance imaging (MRI) diffusion tensor image (DTI). Case Description: A 52-year-old woman had a 2-year history of HFS on the left side of her face. It was confirmed that the left vertebral artery and anterior inferior cerebellar artery were presented near the facial nerve on MRI. REZ of the facial nerve was visualized using DTI and fusion image was created with vascular components, making it possible to recognize the relationship between compression vessels and REZ of the facial nerve in detail. She underwent microvascular decompression and her HFS completely disappeared. We confirmed that the REZ of the facial nerve was decompressed by MRI imaging, in the same way as before surgery. Conclusion: We describe that the REZ of facial nerve and compressive vessels was delineated in detail on MRI and this technique is useful for pre- and postoperative evaluation of HFS.

Endovascular Treatment of Hemifacial Spasm Associated with a Tentorial DAVF Using Transarterial Onyx Embolization: A Case Report.

Objective: We describe a patient treated with transarterial Onyx embolization for a tentorial dural arteriovenous fistula (DAVF) who presented with hemifacial spasm (HFS). Case Presentation: A 56-year-old man suffered from right blepharospasm for 4 years, and the symptom gradually spread to the right side of his face with oculo-oral synkinesis. MRI of the brain revealed abnormal multiple flow voids at the surface of brainstem and cerebellar hemisphere. MRA (time of flight) and spoiled gradient recalled echo-revealed abnormal vessels at the posterior fossa indicated arteriovenous shunting. 3D-MRI fusion images showed that a dilated vein was in contact with the root exit zone (REZ) of the right facial nerve. The right carotid angiography displayed a complex tentorial DAVF on the right side. There were multiple feeding vessels drained to the tentorial sinus at the point where the inferior cerebellar vermian vein met, and severe venous congestion was noted. We diagnosed a tentorial DAVF and thought that this was responsible for the right HFS. We used neuroendovascular treatment for this lesion. After transarterial Onyx embolization, his right HFS diminished. MRI after treatment showed that the vein in contact with the REZ of the right facial nerve had shrank. Conclusion: We experienced a rare case of HFS associated with a DAVF. Our case supports that transarterial Onyx embolization can treat HFS associated with a tentorial DAVF. It is the first description of successful treatment that could be confirmed through postoperative MRI.

Bioresorbable plate fracture after cranioplasty caused by head injury: a pediatric case.

BACKGROUND: Recently, bone fixation materials have been developed as surgical materials. Bioabsorbable materials offer several advantages over other materials and are widely used. We report a rare case of the fracture of bioresorbable plates caused by head injury and describe some considerations. CASE DESCRIPTION: A 6-year-old boy suffered from consciousness disturbance. He was admitted to our hospital and diagnosed with left frontal subcortical hemorrhage due to ruptured arteriovenous malformation (AVM). He received the surgery of removal of the AVM with decompressive craniectomy. He was discharged without any neurologic deficit and underwent the cranioplasty 4 months after the initial surgery. Two months after the last treatment, he was fallen and hit his left frontal head. The next day, he noticed an abnormal bulge in the injured area. We diagnosed the bulging as cerebrospinal fluid leakage because of the dural tear. The repairment of dural tear was performed. We found that two bioresorbable plates used by cranioplasty were both cracked, and the dura mater beneath them was torn. We repaired the damaged dura with an artificial dura mater. After surgery, cerebrospinal fluid leakage did not occur. CONCLUSION: It has been reported that the durability of bioresorbable plates is no less than that of titanium plates. We experienced a relatively rare case in which bioabsorbable plate used for bone fixation was damaged due to head trauma. After craniotomy or cranioplasty using bioresorbable plates, special attention should be paid to head trauma that involves bone flap sinking force and side bending stress.

Coil embolization of subarachnoid hemorrhage with ruptured persistent primitive olfactory artery aneurysm.

BACKGROUND: Persistent primitive olfactory artery (PPOA) is a rare anomaly of the anterior cerebral artery. We experienced a rare case of subarachnoid hemorrhage caused by a ruptured saccular aneurysm of PPOA. CASE DESCRIPTION: A 72-year-old man was transported to our hospital with sudden headache. On examination, World Federation of Neurological Surgeons scale was Grade I, and computed tomography of the head showed subarachnoid hemorrhage in Fisher Group 3. Cerebral angiography showed left PPOA and a 4-mm saccular aneurysm at the hairpin turn. No other abnormalities causing bleeding were observed. Based on these findings, subarachnoid hemorrhage due to a ruptured PPOA aneurysm was diagnosed. As the patient had a ventilatory defect due to emphysema, direct approach to the lesion would have been difficult and an endovascular surgery was performed. Three coils were inserted into the aneurysm, and complete occlusion was achieved. Cerebral vasospasm was not observed, and the patient was discharged 1 month after surgery without any neurologic deficit. CONCLUSION: Most aneurysms of the PPOA are formed at the hairpin turn, as observed in our patient; therefore, a hemodynamic mechanism may be involved in the etiology. To the best of our knowledge, there is no report on treatment using intra-aneurysmal coil embolization, indicating that ours was the first case. As the long-term outcome of intra-aneurysmal coil embolization for PPOA aneurysm is unknown, careful follow-up will be necessary in the future.

Trigeminal Neuralgia Due to Compression of Primitive Trigeminal Artery Variant: Usefulness of Fusion Images of Constructive Interference in Steady-State Magnetic Resonance Imaging and Computed Tomography Angiography.

BACKGROUND: Trigeminal neuralgia (TN) is one of the neuropathic pain syndromes, most commonly caused by vascular compression in the root entry zone of the trigeminal nerve in the cerebellopontine angle. It was rare as offending artery that primitive trigeminal artery and primitive trigeminal artery variant (PTAv) as an anomaly that occurs carotid-basilar anastomosis. We report a case of TN caused by the PTAv, and usefulness of fusion images of magnetic resonance imaging (MRI) and computed tomography angiography (CTA). CASE DESCRIPTION: A 65-year-old man presented with a 2-year history of left paroxysmal facial pain in the second division of the trigeminal nerve. We diagnosed left TN due to PTAv using constructive interference in steady state magnetic resonance imaging (CISS MRI) and CTA. Microvascular decompression surgery disclosed trigeminal nerve compressed by PTAv consisted with findings from preoperative neuroimaging. We report a case of TN caused by PTAv, and usefulness of fusion images of CISS MRI and CTA to understand the neurovascular and bony structure during the perioperative period. CONCLUSIONS: The fusion image created by CISS MRI and 3-dimensional CTA was useful to identify the offending vessel and to clearly understand the neurovascular structure preoperatively.

Delayed acute subdural hematoma treated with endoscopic procedure: A case report.

Background: Delayed acute subdural hematoma (DASDH) is defined as late onset ASDH with the absence of any abnormal radiological and clinical findings at initial examination. Moreover, this entity is very rare in traumatic brain injury and its mechanism is still unclear. Recently, endoscopic surgery for ASDH has also been performed. In this case, we describe some considerations of the mechanism of DASDH and review previous literature and usefulness of endoscopic surgical procedure for ASDH. Case Description: A 73-year-old man fell at night, and visited a former medical institution by himself. No abnormal neurological finding was detected. Head computed tomography (CT) detected no abnormal finding. He was diagnosed minor head injury and was hospitalized at midnight and discharged after brain magnetic resonance image (MRI) next day. Brain MRI also detected no abnormal findings. Three days later, he visited our hospital himself, because of the severe headache. Neurologically, he had a mild consciousness disturbance and head CT revealed left ASDH. We performed endoscopic evacuation of hematoma under local anesthesia. Then, the clot was evacuated under the endoscopic procedure through dilated burr hole and pulsatile bleeding from the cortical artery was observed, which was considered to be the source of the ASDH. The patient's consciousness disturbance was improved immediately after surgery and he discharged without neurological deficit. Conclusion: We revealed the source of bleeding of DASDH under endoscopic procedure and described hypothesis and speculation of its cause in our case. DASDH is rare entity, so we need further experiences and more considerations.

Novel Burr Hole Dilator for Endoscopic Surgery for Intracranial Hemorrhagic Lesion: Technical Note.

OBJECTIVE: When performing burr hole endoscopic neurosurgery, it is necessary to get enough surgical corridor. We have used various instruments to extend burr hole size, but it was cumbersome to use so many tools. METHODS: In this report, we describe a novel instrument-a dilator attachment with a cordless handle to make it simple and safe to extend a burr hole. We developed this burr hole dilator attachment with blades on the side and an arc form on the bottom to prevent dural damage. It can be used to drill safely and efficiently. We describe some experiences of using this device. RESULTS: It is important to balance the maximization of the operation range and surgical invasiveness for endoscopic neurosurgery. This new dilator for extending a burr hole is a safe, useful device to get enough surgical view and easily perform a surgical procedure in endoscopic surgery. CONCLUSIONS: Our dilator for expanding a burr hole improves the work of endoscopic surgery on intracranial hemorrhagic lesions.

[Treatment of Rathke's Cleft Cyst:Technical Note for Preservation of Pituitary Function].

Pituitary dysfunction, such as panhypopituitarism or diabetes insipidus(DI), is often found in patients with Rathke's cleft cyst. Patients were treated with transsphenoidal microscopic surgery; however, pituitary dysfunction did not usually recover. Recently, endoscopic transsphenoidal surgery(eTSS)has enabled minimally invasive surgery for patients with Rathke's cleft cyst. In this study, we analyzed 22 consecutive patients with Rathke's cleft cyst who underwent eTSS to determine if pituitary dysfunction recovered. The follow-up period ranged from 3 months to 19.25 years(mean, 4.75 years). Preoperative endocrinological evaluation showed impaired secretion of adrenocorticotropic hormone(ACTH)in 4 cases(18.2%), thyroid-stimulating hormone(TSH)in 2 cases(9.1%), hyperprolactinemia in 5 cases(22.7%), growth hormone(GH)in 9 cases(40.9%), and luteinizing hormone(LH)/follicle-stimulating hormone(FSH)in 11 cases(50%). In addition, preoperative DI was found in 2 cases(9.1%). We planned the site of fenestration for the cyst wall using preoperative sagittal magnetic resonance imaging. As a result, the recovery rate for ACTH, GH, and TSH secretion was 25%, 33.3%, and 50%, respectively. On the other hand, two patients with DI and other hormonal deficiencies did not recover pituitary function because of severe inflammation. Pituitary function might be preserved with minimally invasive surgery for Rathke's cleft cyst with mild inflammation.

Endoscopic hematoma evacuation for acute subdural hematoma in a young patient: a case report.

Case: The standard treatment for acute subdural hematoma (ASDH) is large craniotomy; decompressive craniectomy may also be carried out, if needed, to prevent secondary brain damage. Recently, an endoscopic procedure for elderly patients with ASDH was carried out and reported; its safety and effectiveness were emphasized because of minimal invasiveness. We report a young case and discuss its difficulties and tips.A 31-year-old man was found to be in a state of general convulsion. At the time of admission, we observed severe consciousness disturbance, anisocoria, and left hemiparesis. Computed tomography showed a massive subdural hematoma with marked midline shift. Outcome: Osmotherapy and emergency trepanation improved anisocoria. An endoscopic procedure under local anesthesia was sequentially selected. After surgery, the patient's symptoms clearly improved. Conclusion: Although the standard treatment for ASDH is craniotomy, endoscopic surgery may be useful in some cases.

Practical use of a simple technique, insertion of wet cotton pledgets into the tumor resection cavity in transsphenoidal surgery of pituitary tumors, for a better comparison between pre- and intraoperative high-field magnetic resonance images.

BACKGROUND: Intraoperative high-field magnetic resonance imaging (iMRI) is a useful modality for immediate intraoperative quality control. With iMRI, a surgeon can confirm whether tumor remnants exist during surgery; which makes it possible to add further resection, obtain a higher resection rate, and improve the cure rate. It is sometimes difficult to evaluate the existence of tumor remnants when the tumor resection cavity is collapsed. In this study, we reported a simple technique for comparing pre- and intraoperative MR images. PATIENTS AND METHODS: Thirty-five consecutive patients with pituitary adenoma underwent endoscopic endonasal transsphenoidal surgery using iMRI. Twenty-six patients had adenomas with suprasellar extension, and 9 had intrasellar adenomas. Nine adenomas had cavernous sinus invasion. Eight patients had endocrine-active, and 27 endocrine-inactive tumors. The simple technique included wet cotton pledgets inserted into the resection cavity to easily and precisely compare pre- and intraoperative MR images. Furthermore, we evaluated the efficacy of iMRI using our method on determining the extent of tumor resection in this study. RESULTS: The first iMRI scan showed that 12 of 35 patients had some tumor remnants, and 23 patients did not. Eight of these 12 patients with tumor remnants had cavernous sinus invasion. Three cases received further tumor resection after iMRI and had a gross total removal. CONCLUSIONS: We presented our initial results after using a simple method in high-field iMRI during endoscopic transnasal transsphenoidal pituitary surgery. This procedure allowed us to obtain valuable information to determine the extent of tumor resection and to precisely visualize the parasellar structures.

Usefulness of multimodal examination and intraoperative magnetic resonance imaging system in glioma surgery.

Extensive surgical removal of tumor tissue can contribute to longer survival for patients with gliomas. Intraoperative magnetic resonance (iMR) imaging is important for safe and maximal resection of brain tumors. A new operating room equipped with a 1.5-T MR imaging system and neuronavigation opened at Yamagata University Hospital in 2008. Using this new suite, we have safely treated over 200 cases. Use of iMR imaging improved glioma resection rates in 25 (34%) of 73 cases, and gross total resection was achieved in 48 patients (66%). Motor evoked potential (MEP) monitoring was performed in combination with iMR imaging for 32 gliomas. MEP monitoring was successful in 30 cases (94%). Transient decreases in MEP amplitude were seen in two patients. One patient showed transient motor weakness and another showed improvement of motor function. The iMR imaging system provides useful information for tumor resection that allows intraoperative modification of surgical strategies. Combining MEP monitoring with iMR imaging appears to offer the most effective method for safe glioma surgery near eloquent areas.

[Long-term outcomes of surgical treatment for epidermoid].

OBJECTIVE: Surgical strategies for epidermoids in our department is that the tumor capsule and surrounding arachnoid membrane should be sharply dissected and resected as much as possible. However, if total resection is not possible, because of the danger of surgical morbidity, partial resection should be carried out. The present study reports on long-term outcomes of surgical treatment for intracranial epidermoid in our department. METHODS: Since 1994, intracranial epidermoids have been resected in 13 patients in our department. The mean age at the time of surgery was 50.2 years and the mean postoperative follow-up period was 75.8 months. Surgical outcome, postoperative morbidity, Karnofsky Performance Status (KPS) during long-term follow-up, hydrocephalus, and regrowth rate were investigated. RESULTS: Among the 13 patients, 5 underwent total resection, 5 subtotal resection, and 3 partial resection. No permanent morbidity occurred and KPS did not worsen postoperatively in any of the patients. Surgery for hydrocephalus was performed in 3 patients. However, hydrocephalus had been suspected before surgery in each patient. Regrowth occurred in 1 patient, showing malignant transformation 1 year after total resection. No regrowth during long-term follow-up was observed in the other 12 patients, and none showed exacerbation of KPS. CONCLUSION: The present study indicates that regrowth does not necessarily occur in patients with epidermoids. Although total resection is ideal, to avoid any surgical morbidity is even more important. Partial resection should be performed if total resection is impossible.

Atypical teratoid rhabdoid tumor located in the pineal region following prophylactic irradiation for acute lymphoblastic leukemia.

Atypical teratoid rhabdoid tumor (AT/RT) is a rare entity. In the central nervous system, AT/RT generally arises from the posterior fossa of infants and behaves aggressively. AT/RT is reported to arise from the infratentorial region (63%) and other sites, such as the suprasellar region, cerebellopontine angle, and spinal cord. The pineal region is rare (6%) as a site of origin. Radiation-induced brain tumors are well known. In this report, we present a case of a pineal region tumor causing acute hydrocephalus that could be pathologically diagnosed as AT/RT following prophylactic cranial irradiation for acute lymphoblastic leukemia.

The alterations of oligodendrocyte, myelin in corpus callosum, and cognitive dysfunction following chronic cerebral ischemia in rats.

Although the white matter lesions, so called leuko-araiosis, often seen in elderly people have been gaining attention due to their association with cognitive dysfunction (CD) and high risk of incident stroke, the pathological significance of these lesions still remains controversial. Therefore, in the present study, we investigated the alterations in oligodendrocytes (OLG), including oligodendrocytes progenitor cells (OPCs), myelin, and CD following chronic cerebral ischemia in rats. SD rats were subjected to bilateral common carotid artery occlusion. Immunohistochemical staining was performed at 2, 4, 6, 8, and 12weeks after the induction of ischemia with anti-NG2 (OPCs), anti-GST-π (OLG), and anti-MBP antibodies in paramedian corpus callosum (CC). CD was assessed by the Morris water maze test. There was a significant decrease in the number of GST-π positive cells at 2weeks after the start of ischemia compared with that seen in the sham group. There was a significant increase of the number of NG2 positive cells at 4weeks in the ischemia group compared with the sham group. In the ischemic group, the amount of MBP was observed to have decreased significantly at each time point compared with the sham group. CD was observed in the ischemic group than that in the sham group at all time points. Our results indicate that remyelination is strongly correlated with the recovery of cognitive dysfunction following chronic cerebral ischemia.

Intraoperative magnetic resonance imaging in the successful surgical treatment of an arteriovenous malformation--case report.

A 44-year-old female presented with left occipital arteriovenous malformation (AVM) manifesting as sudden onset of severe headache. Magnetic resonance (MR) imaging and conventional angiography showed the left occipital AVM with hemorrhage. Intraoperative MR imaging (iMR imaging) and intraoperative time-resolved imaging of contrast-kinetics (iTRICKS) at 1.5 T revealed complete removal of the nidus of the AVM without conventional catheter angiography. Conventional catheter angiography is commonly used in preoperative and intraoperative examination of AVMs, and for documentation of the surgical outcome, but less-invasive techniques are desirable for both preoperative screening and intraoperative examination. iMR imaging with iTRICKS is less invasive and safer than conventional angiography for both brain tumor surgery and AVM surgery.

Technical notes on endoscopic transnasal transsphenoidal approach for clival chondrosarcoma.

Although there are various operative approaches for clival tumors, a transsphenoidal approach is one of choices when the main tumor extention is in an anterior-posterior direction with a slight lateral extension. However, this approach sometimes provides only narrow and deep operative field. Recently, endoscopic transnasal transsphenoidal approach is quite an effective approach for clival tumors because of the improvement of surgical instruments, image guidance systems, and techniques and materials of wound closure. In this paper, we describe the effectiveness, technical problems, and solution of this approach based on our experiences with two clival chondrosarcomas that was removed by endoscopic transnasal transsphenoidal approach.