Shinya Ichimura

Four subtypes of petroclival meningiomas: differences in symptoms and operative findings using the anterior transpetrosal approach

SummaryBackground. Petroclival meningiomas are vaguely defined as tumours arising from the antero-medial zone to the internal auditory meatus. This report subclassifies petroclival meningiomas based on their origin determined by using radiological and intra-operative findings.Method. Ninety-one patients with petroclival meningioma underwent surgery via the anterior transpetrosal approach. The Meckel’s cave was routinely opened. Tumour origin was classified into four subtypes according to the main attachment and trigeminal nerve deviation into, upper clivus (UC), cavernous sinus (CS), tentorium (TE), and petrous apex (PA). Their characteristic clinical symptoms and anatomical features were investigated.Findings. The characteristic symptom was ataxia in the UC type (37.5%), abducens nerve palsy in the CS type (64.3%) and trigeminal neuropathy, mainly neuralgia in the PA type (80.0%) with a higher statistical difference from other subtypes. The rate of tumour invasion into Meckel’s cave reached 70.3% in average, with the lowest rate in the PA type (25.0%). The rate of middle fossa extension was the highest in the TE type (59.5%). The middle fossa approach was considered to be ideal for UC and TE types because of easier access to the Meckel’s cave. Radical dissection without complications was difficult in the CS type. Both the anterior transpetrosal approach and the lateral suboccipital approach could be indicated in the PA type due to the rare invasion of Meckel’s cave and middle fossa, and frequent extension into the internal auditory meatus.Conclusions. This classification is useful to predict the relation between the tumour and the cranial nerves based on symptoms and images. The anterior transpetrosal approach could be used for all four subtypes and with an absolute indication in the UC and TE types showing middle fossa extension.

Greater petrosal nerve schwannomas—analysis of four cases and review of the literature

Schwannomas arising from the greater petrosal nerve (GPN) are exceedingly rare: only 10 such cases have been reported in the English literature. We report on four cases of GPN schwannomas and discuss the surgical approach for their removal. Four patients with GPN schwannomas underwent surgery at Keio University Hospital. We present the pre- and postoperative clinical findings and describe the structures around the GPN schwannomas as observed during the surgery. Histological sections were performed around the GPN using Masson’s trichrome stain to elucidate the membrane structures. Three patients presented with xerophthalmia, and one with facial palsy, hearing disturbance, and generalized convulsions. Contrast-enhanced magnetic resonance images revealed tumors in the temporal lobe. Bone-window computed tomography showed erosion of the anterior petrous apex. During the operation, the temporal lobe was retracted epidurally. The tumors were visible inside the interdural space and covered with the epineurium. In three cases, the tumors were completely removed, and in one case, the tumor was subtotally removed with intraoperative facial monitoring. In the histological sections, we confirmed that the GPN ran within the interdural space. Approaching epi- and interdurally is suitable for the removal of GPN schwannomas because the GPN is located within the interdural space. The advantage of this approach is that the landmark points can be identified. Moreover, the possibility of injuring the temporal lobe is low because the temporal lobe is not exposed in this approach.

Surgical approach for hypoglossal schwannomas to prevent deformity of the atlanto-occipital joint

BackgroundHypoglossal schwannomas are very rare tumors that often enlarge the hypoglossal canal and jugular foramen, and erode the bone bridge of the occipital condyle. We compared pre- and postoperative 3D bone CT images and discussed the ideal craniotomy to prevent fracture formation.MethodSeven patients with hypoglossal schwannomas underwent surgery in our department. Six cases were type B and 1 case was type C. All patients complained of hypoglossal nerve paresis and nuchal pain.FindingsWe used the condylar fossa approach for four cases of type B, the lateral suboccipital approach with C1 laminectomy for two cases of type B and extradural transjugular approach for one case of type C. In all cases, the lateral rim of the foramen magnum or the posterior rim of the jugular foramen was not resected at the same time. The intracranial part of the tumor was removed in all type B cases. Radiotherapy was added for the residual tumor. No patient had deformity or fracture of the joint.ConclusionsOpening the hypoglossal canal and dural incision toward the hypoglossal canal are important for high radicality. However, preservation of the lateral rim of the foramen magnum must be noted to prevent consecutive deformity or fracture of the atlanto-occipital joint.

Executive dysfunction is related with decreased frontal lobe blood flow in patients with subarachnoid haemorrhage

Abstract Objective: This study evaluated executive dysfunction in patients with subarachnoid haemorrhage (SAH) using the Behavioural Assessment of the Dysexecutive Syndrome (BADS) and correlated the occurrence of executive dysfunction with cerebral blood flow (CBF) reduction in the frontal lobe as assessed by single photon emission computed tomography (SPECT). Design: Correlational study. Subjects: Twenty-two patients who underwent microsurgical clipping at least 3 months after SAH. Methods: This study evaluated the BADS and the Wechsler Adult Intelligence Scale-III (WAIS-III). In addition, it assessed activities of daily living (ADL). CBF was evaluated using SPECT. The patients were divided into the following groups according to the results of SPECT: (1) those with reduced CBF in the frontal lobe (reduced CBF group, n = 8) and (2) those with intact CBF (intact CBF group, n = 14). Results: The BADS score was significantly lower in the reduced CBF group compared with that of the intact CBF group, while there was no significant difference in the WAIS-III scores and ADL scale between the two groups. Conclusion: Although this result was conducted with a small sample size, executive dysfunction correlates with reduced CBF in the frontal lobes of SAH patients. A detailed evaluation of executive function is suggested in SAH patients, even if the patient’s intelligence test and ADL scale reveal no abnormalities.

Epidural anterior petrosectomy with subdural visualization of sphenobasal vein via the anterior transpetrosal approach—technical case report

The drainage of the superficial middle cerebral vein (SMCV) is classified into four subtypes. The sphenobasal vein (SBV) drains from the SMCV to the pterygoid venous plexus at the temporal skull base. Epidural procedures in the standard anterior transpetrosal approach (ATPA) may damage the route of the SBV. We report a case in which modified surgical procedures via the ATPA were used to preserve the SBV. A 45-year-old man complained of right facial pain. Magnetic resonance images revealed a right cerebellopontine tumor suggestive of an epidermoid cyst. Right carotid angiography revealed that the SMCV drained into the pterygoid venous plexus via the SBV. The convexity dura mater of the temporal lobe was cut and the anterior part of the temporal lobe was retracted subdurally. The SBV was visualized from the subdural side. The basal dura mater of the temporal lobe posterior to the SBV was cut and the posterior part of the temporal lobe was retracted epidurally. After dissecting the dura mater medial to the greater petrosal nerve and to the edge of the petrous apex, the petrous apex was exposed and drilled out without injuring the SBV. The superior petrous sinus and the tentorium were cut. The tumor compressed the root exit zone of the trigeminal nerve. The tumor was grossly totally removed. The modified ATPA (epidural anterior petrosectomy with subdural visualization of the SBV) is effective in preserving the SBV.

A Case of Intraosseous Microcystic Meningioma Without a Mass Lesion

Both intraosseous and microcystic meningiomas are rare tumor types. We report the case of a 66-year-old woman with intraosseous microcystic meningioma without a mass lesion. She presented with a rare intraosseous microcystic meningioma manifesting as pain. Radiological examination revealed an osteolytic lesion in the right parietal bone. Magnetic resonance (MR) images showed iso- to hypointensity on T1-weighted images and hyperintensity on T2-weighted images corresponding to the lesion. T1-weighted MR imaging with gadolinium enhancement better defined the marginal area. The inner table of the skull was disrupted prominently, and both sides of the outer table were eroded. There was fluid leakage during surgery but no obvious tumor mass. Histological examination revealed microcystic meningioma in the inner part of the defective bone. A macroscopic lesion was not found, because most of the tumor comprised microcysts, and their contents leaked out during the surgical procedure. Intraosseous microcystic meningioma may be considered as one of the differential diagnoses when the intraosseous tumor in the skull has fluid leakage and does not have a mass lesion during the surgery.

Nontraumatic acute subdural hematoma associated with the myelodysplastic/myeloproliferative neoplasms.

98 Journal of Neurosciences in Rural Practice | January April 2012 | Vol 3 | Issue 1 SDH showed good recovery on conservative management. Although the spinal SDH cleared spontaneously in our patient, there was intracranial subdural rebleed, requiring surgical evacuation. In the presence of a spontaneous spinal hematoma, MRI of the brain and the entire spine is essential for complete diagnosis and early prompt management.

A Case of Large Anterior Paraclinoid Aneurysm with Intraoperative Premature Rupture

We report here troubleshooting of intraoperative premature rupture with large anterior paraclinoid aneurysm, which was successfully clipped. A 61-year-old woman with left nasal hemianopia was referred to our institute. Preoperative three-dimensional computed tomography angiography and a left internal carotid artery angiogram showed a large left anterior clinoid aneurysm adjacent to the anterior clinoid process. Aneurysm was ruptured prematurely and tentative clipping of the dome of the aneurysm was done incidentally to stop bleeding and to reduce the volume of the aneurysm. The anterior clinoid process and superior wall of the orbit were drilled out safely, since the tentative clipping had created sufficient space between the aneurysm and the anterior clinoid process to perform the procedure. The proximal neck was observed and tandem clipping was applied to the aneurysm. Intraoperative and postoperative angiography revealed complete disappearance of the aneurysm.

Treatment of Hyponatremia with Tolvaptan in a Patient after Neurosurgical Treatment of a Pituitary Tumor: Case Report and Review of Literature

Hyponatremia is a frequent complication following pituitary surgery. We report a case with hyponatremia after surgery of a pituitary adenoma that was successfully treated with tolvaptan. A 68-year-old man with a pituitary tumor presented with mild hyponatremia (133 mEq/L) before surgery. The patient developed hyponatremia (125 mEq) 4 days postsurgery, and 10% sodium chloride was infused. Seven 7 days postsurgery, hyponatremia was improved (132 mEq/L), and tolvaptan 15 mg was given orally as a single dose instead of the 10% sodium chloride infusion. His serum sodium remained within normal limits. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) after pituitary surgery most probably led to the hyponatremia, and tolvaptan was effective because it is an oral vasopressin receptor antagonist.

Spontaneous spinal epidural hematoma (SSEH) after coil embolization of cerebral aneurysm: implication of high SSEH frequency in East Asia.

Spontaneous spinal epidural hematoma (SSEH) is a rare disease ith extremely serious symptoms and is triggered by antithromotic use [1]. However, the proportion of unruptured aneurysms reated by coil embolization has increased from 20% in 2001 to 63% n 2008 in the US, and antithrombotics are necessary to prevent hromboembolic complications. Other endovascular procedures ave also gained popularity; hence, more patients are exposed to ntithrombotics. To date, only 2 SSEH cases following endovascular reatment have been reported. One study found an SSEH following mplantation of coronary artery stents to treat acute myocardial nfarction [2]. The other found an SSEH associated with direct atheter thrombolytic therapy for deep vein thrombosis (DVT) [3]. his is the first report of an SSEH occurring after coil embolization or cerebral aneurysm. A 65-year-old man was referred to our hospital after invesigations performed at another hospital indicated right anterior