Arterial spin labeling imaging correlates with the angiographic and clinical vascularity of vestibular schwannomas.

PURPOSE: Hypervascular vestibular schwannomas (HVSs) are a type of the vestibular schwannomas (VSs) that are extremely difficult to remove. We examined whether HVSs can be predicted by using arterial spin labeling (ASL) imaging. METHODS: A total of 103 patients with VSs underwent ASL imaging and digital subtraction angiography (DSA) before surgery. Regional cerebral blood flow (CBF) of gray matter and regional tumor blood flow (TBF) were calculated from ASL imaging, and we defined the ratio of TBF to CBF as the relative TBF (rTBF = TBF/CBF). Angiographic vascularity was evaluated by DSA, and clinical vascularity was evaluated by the degree of intraoperative tumor bleeding. Based on the angiographic and clinical vascularity, the VSs were divided into two categories: HVS and non-HVS. We compared rTBF with angiographic and clinical vascularities, retrospectively. RESULTS: The mean rTBFs of angiographic non-HVSs and HVSs were 1.29 and 2.58, respectively (p < 0.0001). At a cutoff value of 1.55, the sensitivity and specificity were 93.9% and 72.9%, respectively. The mean rTBFs of clinical non-HVS and HVSs were 1.45 and 2.22, respectively (p = 0.0002). At a cutoff value of 1.55, the sensitivity and specificity were 79.4% and 66.7%, respectively. CONCLUSION: The rTBF calculated from ASL imaging correlates well with tumor vascularity and may be useful for predicting HVSs before surgery.

Middle Fossa Approach for Facial Nerve Schwannoma Aiming for Functional Improvement: 2-Dimensional Operative Video.

The treatment paradigm of skull base surgery has been changed from radical tumor resection to maximal tumor removal while giving priority to functional preservation. Facial nerve schwannoma is one of the representative disorders of this type of paradigm shift.1 This video demonstrates facial nerve schwannoma surgery through the middle fossa approach, aiming for improvement of facial function. A 33-yr-old woman presented with gradually worsening facial palsy (House-Brackmann grade IV), dizziness, and nausea. Neuroimaging revealed a growing tumor involving the geniculate ganglion, and extending to the middle fossa, internal acoustic meatus, and cerebellopontine angle. The nerve-sparing surgery through the left middle fossa approach was performed under detailed neuromonitoring including the evoked facial electromyograms and auditory brainstem response. The facial nerve fibers were involved within the tumor mass and the plane between the tumor and facial nerve could not be identified as seen in most cases of such large facial nerve schwannomas. But sufficient tumor removal with facial nerve preservation was achieved owing to continuous facial monitoring.2 The patient had no new neurological deficits. Her facial palsy has been gradually improving, now at grade III, without any signs of tumor regrowth during the 10 mo of follow up after the operation. Careful follow up is being continued to survey the possible tumor recurrence. The video was reproduced after informed consent of the patient.

Extradural Transjugular Transsigmoid Approach with High Cervical Exposure for Glomus Jugulare Tumor.

Surgical removal of glomus jugulare tumors is challenging owing to the complex anatomy of the temporal bone and craniocervical region, aggressive tumor invasion into the nearby structures, and their hypervascularity. However, recent advances in skull base techniques, intraoperative neuromonitoring, and radiological interventions have enabled their relatively safe resection, while giving priority to functional preservation. This video demonstrates a case of a glomus jugulare tumor treated by the extradural transjugular transsigmoid approach with high-cervical exposure and tympamoplasty, after preoperative embolization. A 47-year-old woman presented with progressive hearing disturbance, pulsatile tinnitus, and hemifacial spasm. Neuroimaging displayed a hypervascular tumor occupying the temporal bone, extending to the cervical region through the jugular foramen, and to the external auditory canal. Preoperative feeder occlusion was successfully performed without any additional symptoms, while carefully evaluating the provocative test. Near-total resection of the tumor was achieved through the transjugular transsigmoid approach with high-cervical exposure under detailed neuromonitoring, including continuous facial nerve monitoring and auditory brainstem response. In this patient, in whom the tumor did not invade intradurally and the sigmoid sinus was already occluded preoperatively, the sinus was managed only by coagulation, to avoid unnecessary dural opening and the risk of cerebrospinal fluid leakage. Anterior facial nerve rerouting was not required since the tumor removal was accomplished through the corridor above and below the fallopian bridge. The patient had no new neurological deficits, and her pulsatile tinnitus and hemifacial spasm disappeared after the surgery. Her hearing disturbance improved postoperatively. The link to the video can be found at: https://youtu.be/gqf3dxHlv_0 .

Anterior Transpetrosal Approach for Trigeminal Schwannoma with Persistent Primitive Trigeminal Artery: 2-Dimensional Operative Video.

The surgical management of trigeminal schwannomas often requires complicated skull base approaches based on detailed anatomical understanding because of the involvement of multiple compartments of the trigeminal nerve from its root to the peripheral branches. When there is vital anatomical anomaly around the tumor, this can make the surgical management and anatomical understanding more difficult.1,2 This video demonstrates the microsurgical removal of a dumbbell-shaped trigeminal schwannoma via the anterior transpetrosal transtentorial approach in a patient with a persistent primitive trigeminal artery, the most common persistent embryonic carotid-vertebrobasilar anastomosis. A 32-yr-old woman presented with progressive facial sensory impairment, dizziness, and slight diplopia because of right abducens palsy. Neuroimaging revealed a right Meckel's cave tumor extending to both the middle and posterior cranial fossae and displacing the abducens nerve inferomedially. The persistent primitive trigeminal artery, which is an anomalous communication between the cavernous carotid and basilar arteries, was identified ventral to the tumor. While preserving most of the noninvaded trigeminal nerve, gross-total resection was achieved under direct visualization of the abducens nerve and persistent primitive trigeminal artery, piercing the dura of the posterior cavernous sinus and coursing medially along the clivus. The patient's facial sensory impairment and diplopia almost disappeared without new neurological deficits or tumor recurrence during the follow-up period of 1 yr. Three-dimensional reconstructed images demonstrated the anatomical relationship of the tumor, the persistent primitive trigeminal artery, and the extent of osseous drilling of the petrosectomy. Informed consent was obtained from the patient.

Retrosigmoid Intradural Suprajugular Approach to Jugular Foramen Tumors with Intraforaminal Extension: Surgical Series of 19 Cases.

OBJECTIVE: The intraforaminal component of jugular foramen tumors is difficult to access surgically, as it requires complex approaches for radical removal and leads to a high recurrence due to residual tumor. The retrosigmoid suprajugular approach, intradural drilling of the roof of the jugular foramen, has been recently proposed for removal of such intraforaminal component without sacrificing the sigmoid-jugular venous system or requiring additional approaches. This study presents our experience with this approach and introduces the use of intraoperative continuous vagus nerve monitoring. METHODS: Nineteen patients (14 with neuromas and 5 with meningiomas) were operated using this approach over a 12.5-year period. In the more recent 14 cases, continuous vagus nerve monitoring was performed with a ball-type electrode placed on the proximal vagus nerve. RESULTS: More than 95% of the tumor removal was achieved in all but the first neuroma case. Extubation immediately after surgery and oral feeding within a week postoperatively was achieved in all patients. Seven of 9 patients with preoperative hearing disturbance symptomatically improved after surgery. All but the first case had no signs of recurrence during the follow-up period (average of 58 months). CONCLUSIONS: The retrosigmoid suprajugular approach is safe and effective for removal of tumors extending into the jugular foramen, maintaining a chance of hearing improvement. Intraoperative continuous vagus nerve monitoring is useful to avoid postoperative complications in such surgeries.

Partial Transcondylar Approach for Ventral Foramen Magnum Neurenteric Cyst: 2-Dimensional Operative Video.

The anterior foramen magnum area, ventral to the brainstem is one of the most difficult regions to access surgically, and the extent of osseous drilling through the far-lateral or transcondylar approach should be planned in each case based on the tumor extension.1,2 This video, reproduced after informed consent of the patient, demonstrates a case of a ventral foramen magnum neurenteric cyst surgically treated using the partial transcondylar approach. A 27-yr-old woman presented with gait disturbance, oscillopsia, and transient arm numbness. Neuroimaging revealed a ventral foramen magnum cystic tumor involving the basilar and bilateral vertebral arteries. The tumor extended inferiorly from the middle clivus to the C1 level, and occupied the whole premedullary cistern compressing the bilateral lower cranial nerves. The left partial transcondylar approach was performed with drilling the condylar fossa, superior part of the occipital condyle, C1 posterior arch, and posterior part of the jugular process to achieve the sufficient surgical view from the inferolateral side. The drilling of the occipital condyle was minimized so that the articular facet of the occipital condyle was preserved. The tumor on the bilateral side was completely removed as enabled by the sufficient surgical field without new neurological deficits. Three-dimensional reconstructed images based on the postoperative computed tomography scans demonstrated the appropriate extent of the osseous drilling.

Preservation of Venous Drainage in Middle Fossa During Combined Transpetrosal Approach for Petroclival Meningioma.

The combined transpetrosal approach enables wide exposure around the petroclival region by lifting of the middle fossa dura and cutting of the tentorium. However, interruption of the venous drainage on the middle skull base during the transpetrosal approach has been reported to lead to temporal lobe damage.1,2Video 1 demonstrates a microsurgical technique for the preservation of various venous drainage in the middle fossa including the sphenobasal and sphenopetrosal veins during the combined transpetrosal approach for treatment of a petroclival meningioma. The patient is a 51-year-old woman with a petroclival meningioma extending into the cavernous sinus. The superficial middle cerebral vein drained into the foramen ovale as the sphenobasal vein, and the sphenopetrosal vein draining into the superior petrosal sinus coursed on the middle skull base. A developed middle meningeal vein was also identified on the middle skull base. While preserving the venous drainage in the middle fossa by a modified incision of the middle fossa dura, sufficient decompression of the brainstem was achieved by removal of the cisternal part of the tumor. The patient developed diplopia after the surgery, but her headache and dizziness were improved without other neurologic deficits. The patient's diplopia improved within 1 year after the surgery, without any other neurologic deficits or tumor regrowth during the follow-up period of 3 years. Informed consent was obtained from the patient.

Solitary tentorial sarcoid granuloma associated with Propionibacterium acnes infection: case report.

Sarcoidosis is a systemic granulomatous disease with unknown cause, which very rarely occurs exclusively in the central nervous system. The authors performed biopsy sampling of a mass that developed in the left tentorium cerebelli that appeared to be a malignant tumor. The mass was diagnosed as a sarcoid granuloma, which was confirmed with the onset of antibody reaction product against Propionibacterium acnes. Findings suggesting sarcoidosis to be an immune response to P. acnes infection have recently been reported, and they give insight for diagnosis and treatment of this disease. The authors report the possible first case that was confirmed with P. acnes infection in a meningeal lesion in solitary neurosarcoidosis.

Usefulness of embolization of the middle meningeal artery for refractory chronic subdural hematomas.

BACKGROUND: Chronic subdural hematoma (CSDH) is generally treated by burr hole irrigation. However, sometimes repeated recurrence is observed, and treatment may consequently become difficult. We examined the efficacy of embolization of the middle meningeal artery (MMA) for such cases. METHODS: We considered embolization of the MMA for three patients who had refractory CSDH with repeated recurrence and two CSDH patients who were at risk of recurrence and showed signs of recurrence after surgery. A microcatheter was advanced through the MMA as peripherally as possible, and embolization was performed with 15-20% n-butyl-2-cyanoacrylate or 200 µm polyvinyl alcohol particles. RESULTS: EMBOLIZATION WAS PERFORMED IN THE THREE PATIENTS WHO HAD REFRACTORY CSDH WITH REPEATED RECURRENCE: The procedure was performed after burr hole irrigation of the hematoma in two patients and before the irrigation in one patient. In the two CSDH patients at risk of recurrence, embolization was performed when signs of recurrence appeared. The timing of embolization differed for each patient. However, in all the patients, the hematoma tended to decrease in size, and no recurrence was observed. CONCLUSION: Embolization of the MMA is effective for refractory CSDH or CSDH patients with a risk of recurrence, and is considered an effective therapeutic method to stop hematoma enlargement and promote resolution.

Mixed pial-dural arteriovenous malformation in the anterior cranial fossa--two case reports.

Most arteriovenous malformations (AVMs) associated with the meningeal artery in the anterior cranial fossa are the pure dural type, and mixed pial-dural AVMs are rare. Two types of mixed pial-dural AVM occur in the anterior cranial fossa according to the shunting point: one with the nidus in the brain parenchyma of the frontal lobe, and the other with the shunting point in the dura mater. We describe two patients with AVMs fed by the anterior ethmoidal arteries and the persistent primitive olfactory artery, with the nidus located in the pure brain parenchyma of the inferior aspect of frontal lobe, and drained via an abnormal cortical vein into the cavernous and superior sagittal sinuses. The importance of occluding the venous outflow to obliterate intracranial dural arteriovenous fistula (AVF) is emphasized. However, removal of the nidus in the brain parenchyma is required. The presence of a pial feeder should be considered before diagnosis of dural AVF of the anterior cranial fossa, and preoperative detailed evaluation for the pial supply and shunting point is mandatory.

Primary suprasellar malignant tumor with odontogenic features: case report.

OBJECTIVE: Primary malignant odontogenic tumors in the suprasellar region have rarely been reported. CLINICAL PRESENTATION: A partially cystic tumor that originated from the stalk and showed rapid enlargement was observed in a 56-year-old woman. INTERVENTION: Gross total removal of the tumor was performed with sacrifice of the stalk. The tumor was a malignant epithelial type with odontogenic features, whereas findings consistent with craniopharyngioma were absent. The tumor recurred 14 months after surgery. CONCLUSION: The present unusual tumor may represent a novel member of malignant tumors of the suprasellar region. Given the common embryological origin of craniopharyngiomas to odontogenic lesions, a possible correlation with craniopharyngioma was suggested.

Dural suturing for repair of cerebrospinal fluid leak in transnasal transsphenoidal surgery.

OBJECTIVE: Repair of a cerebrospinal fluid (CSF) leak after transsphenoidal surgery (TSS) is usually accomplished using various graft materials. These methods are effective in most, but not all, cases. METHODS: Since 2006, we have been directly suturing the sellar floor dura in patients with an intraoperative CSF leak. Fat and/or fascial grafts were utilized only when a major CSF leak developed. The incidence of postoperative CSF rhinorrhea was compared before and after the suture. RESULTS: Postoperative CSF rhinorrhea developed in 3.7% (7 out of 188) of cases before 2005, but never since the dural suture was introduced (0 out of 136, 0%; P = 0.0229). Although watertight closure was not achieved in some cases, narrowing the dural defect and supporting the intrasellar graft was attained in every case. Surgical time was approximately 30 min longer in patients who underwent dural suture (148 +/- 42 min) than those who did not (119 +/- 37 min; P = 0.0001). CONCLUSION: Direct suturing of the sellar dura is a simple, safe, and reliable surgical technique for repairing CSF leaks after TSS. Using this procedure, more than 70% of patients with an intraoperative CSF leak can avoid autologous tissue grafts.

Headaches associated with Rathke's cleft cyst.

OBJECTIVE: Headaches are common presentations in patients with Rathke's cleft cyst (RCC). This study was conducted to elucidate the characteristics and underlying mechanisms of the headache. METHODS: We retrospectively studied 46 patients with RCC, 33 of whom underwent surgical intervention. RESULTS: Headache, particularly frontal headache, was the most common symptom, occurring in 27 patients (58.7%). Eleven patients with sudden episodic headache mimicking that of pituitary apoplexy. Although the presence of headache did not correlate with cyst size, it was significantly more common in RCCs with: high- and iso intensity content on T1-weighted MR image (P= .0363), mucous content within the cyst (P= .0023), and intense chronic inflammation at the cyst wall (P= .0276). Among 6 patients with histologically recognized intense inflammation, every patient had frontal headache (P= .0407), 5 patients had episodic headache (P= .0002), and 4 patients had associated hypopituitarism (P= .0073), none of which improved after surgical intervention. Headaches improved after surgery in 17 of 21 patients (81.0%). CONCLUSIONS: Headache, particularly frontal episodic headache, is a common and characteristic manifestation in patients with RCC and may indicate intermittent inflammatory reactions caused by mucous content. Patients with episodic headache should undergo surgical treatment to prevent exacerbation of the inflammation that can result in irreversible endocrine dysfunction.

Magnetic resonance imaging, clinical manifestations, and management of Rathke's cleft cyst.

OBJECTIVE: The management of Rathke's cleft cyst (RCC), particularly in patients with no symptoms or with only minor endocrinopathies, has not yet been established. We retrospectively analysed patients with RCC to elucidate correlations between the clinical manifestations, magnetic resonance imaging (MRI) findings, histology and therapeutic outcomes. METHODS: We retrospectively studied 37 patients with RCC, who underwent computed tomography (CT), MRI and endocrinological examinations, of whom 27 patients underwent surgical intervention. RESULTS: The presence of frontal headaches and anterior pituitary dysfunction was unrelated to the cyst size but was more frequent in patients with high- and isointensity cysts on T1-weighted images (WIs) than those with low-intensity cysts (P=0.0159 and P=0.0249, respectively). All three patients with posterior pituitary dysfunction had a high-intensity cyst on T1-WI (P=0.0385), whereas pituitary dysfunction was not observed in patients with a low-intensity cyst on T1-WI. In contrast to the excellent therapeutic outcomes with regard to visual disturbance and hyperprolactinaemia, recovery of pituitary dysfunction was rare; only three of nine patients with hypopituitarism showed improvement. Among six patients with histologically recognized intense chronic inflammation in the cyst wall, five patients had an RCC of T1 high intensity (P=0.0161), two patients had distinct rim enhancement on MRI (P=0.0060), all patients had frontal headaches (P=0.0130), and four patients had associated hypopituitarism (P=0.0243), none of which improved after surgical intervention. CONCLUSION: RCCs of high- and isointensity on T1-weighted images, which contain mucous material within the cyst, may be associated with chronic inflammation that can potentially cause irreversible endocrine dysfunction. In asymptomatic patients with RCCs of these MR intensities, close follow-up with precise endocrinological evaluation and gadolinium-enhanced MRI is necessary to avoid occult progression of the inflammation.