Preoperative evaluation of the petrosal vein with contrast-enhanced PRESTO imaging in petroclival meningiomas to establish surgical strategy.

The present detailed radiological study investigated the relationship between petroclival meningiomas and petrosal veins with contrast-enhanced (CE) principles of echo-shifting with a train of observations (PRESTO) imaging to assess the potential contribution of the findings to the surgical strategy. Fourteen patients (13 women and 1 man) with unilateral petroclival meningiomas underwent microsurgical resection at Osaka City University Hospital between April 2009 and February 2011. Preoperatively, patients were examined using computed tomography (CT) and magnetic resonance (MR) imaging, including CE PRESTO imaging, focusing on the relationship between the tumor and the petrosal vein, and compared to the sensitivity of three-dimensional CT (3D-CT) venography or conventional MR imaging, including CE MR venography and constructive interference in steady-state (CISS) MR imaging. In 11 of 14 cases, we could identify the petrosal veins with intraoperative findings. In 10 of these 14 cases, the anatomical relationship between the tumor and the petrosal vein was detected preoperatively with CE PRESTO imaging, compared to 5 of 14 cases with 3D-CT venography, 5 of 14 cases with CE MR venography, and only 4 of 14 cases using CISS MR imaging. CE PRESTO imaging compares favorably to other approaches. There was no venous complication related to the surgery in any of the cases. CE PRESTO imaging is a non-invasive and useful method to assess the status of the petrosal vein in patients with petroclival meningiomas.

Analysis of venous drainage from sylvian veins in clinoidal meningiomas.

OBJECTIVE: To categorize clinoidal meningiomas according to their venous drainage patterns, and use each category as a guideline to establish an appropriate surgical strategy. METHODS: We performed a retrospective analysis of 22 consecutive surgically treated patients with clinoidal meningioma who underwent preoperative digital subtraction angiography to examine the characteristics of the venous drainage system. These patients were categorized into: 1) cortical type in which the sylvian vein did not drain medially but drained to cortical veins, 2) sphenobasal type in which the sylvian vein drained into the pterygoid plexus, or 3) cavernous type in which the sylvian vein drained into the cavernous sinus directly through the sphenoparietal sinus. We tailored the surgical strategy to preserve these draining veins. RESULTS: Preoperative angiographic evaluation demonstrated 14 patients (63.6%) with cortical type, 6 patients (27.3%) with sphenobasal type, and 2 patients (9.1%) with the cavernous type. In most cases, no restriction from the venous structure was observed because the sylvian vein belonged to the cortical type. However, in the case of the sphenobasal or sphenoparietal type, the surgical strategy seemed to be tailored to preserve the venous drainage system. CONCLUSIONS: The surgical risk from venous complication in the treatment of clinoidal meningiomas appears to be low; however, there are likely to be patients that require a tailored surgical approach to avoid venous complications. Detailed preoperative assessment of anatomic structure and consideration of the optimal surgical strategy are critical to improve treatment outcomes.

Oncogenic osteomalacia associated with mesenchymal tumor in the middle cranial fossa: a case report.

INTRODUCTION: Tumor-induced osteomalacia is a paraneoplastic syndrome of hypophosphatemia. Osteomalacia causes multiple bone fractures and severe pain. CASE PRESENTATION: We report the case of a 57-year-old Japanese man with tumor-induced osteomalacia associated with a middle cranial fossa bone tumor. The tumor was successfully resected by using a middle fossa epidural approach. His phosphate level recovered to a normal range immediately after the surgery. CONCLUSIONS: It is rare that tumor-induced osteomalacia originates from the middle skull base. This report suggests that, if patients have a clinical and biochemical picture suggestive of tumor-induced osteomalacia, it is crucial to perform a meticulous examination to detect the tumor or the lesion responsible for the tumor. The serum level of fibroblast growth factor 23 is the most reliable marker for evaluating the treatment outcome of tumor-induced osteomalacia.

Bilateral subfrontal approach for tuberculum sellae meningiomas in long-term postoperative visual outcome.

OBJECT: Various surgical approaches, such as uni- and bifrontal, frontolateral, and pterional approaches, have been advocated for tuberculum sellae meningiomas. The authors retrospectively reviewed the effectiveness of a bilateral subfrontal approach for tuberculum sellae meningiomas with special attention to ophthalmological outcomes and complications. METHODS: Between 1993 and 2009, 34 patients underwent surgery for removal of tuberculum sellae meningiomas at Osaka City University. Tumor size ranged from 14 to 45 mm. Thirty-two of 34 patients presented with visual disturbances before the surgery. The visual functions in all patients were assessed using a visual impairment score (VIS) before and after surgery. Postoperative visual examination was performed 2 weeks after surgery. Long-term follow-up examinations were conducted 1 year after surgery. RESULTS: Radical resection (Simpson Grades I and II) was accomplished in 27 patients, and subtotal or partial resection (Simpson Grades III and IV) was achieved in 7. There was no deterioration in postoperative visual outcome. Twenty-nine (90.6%) of 32 patients showed improved VIS compared with preoperative VIS. The average VIS was 38.1 preoperatively, 23.5 in the short-term postoperative period, and 21.8 in the long-term postoperative period. In the short-term postoperative period, the visual function in 6 patients normalized, and visual problems persisted in the remaining 26. Six (23%) of 26 patients showed further improvement in VIS during the long-term follow-up period, and no patient exhibited a worsened VIS during this time. One patient complained of hyposmia after surgery, but there was no indication of related complications such as CSF leakage or frontal brain contusion. CONCLUSIONS: The bilateral subfrontal approach was previously avoided because of the relatively high rate of complications in earlier surgical series of tuberculum sellae meningiomas. However, after developments in microsurgical techniques in recent years, the bilateral subfrontal approach can now provide satisfactory visual outcomes with minimal postoperative complications. Careful preservation of the blood supply to optic apparatus and early unroofing of the optic canal using a bilateral subfrontal approach led to further improvement in long-term postoperative visual outcome.

Middle skull base approach with posterolateral mobilization of the geniculate ganglion to access the clival regions.

BACKGROUND: Clival lesions remain one of the most challenging intracranial tumors to treat surgically. Many skull base approaches have been described to improve resection and to decrease patient morbidity. OBJECTIVE: To describe a middle skull base approach with posterolateral mobilization of the geniculate ganglion of the facial nerve to access the clival regions. METHODS: Three patients with petroclival chordoma and 1 patient with petroclival meningioma underwent surgical resection of lesions with our new procedure. Surgical techniques consisted of temporal craniotomy and exposure of the facial nerve from the tympanic segment to the labyrinthine segment, keeping the fundus of the internal auditory canal intact. The geniculate ganglion was mobilized posterolaterally, followed by drilling of the cochlea and exposure of the Dorello canal. RESULTS: Four lesions were successfully removed with complete preservation of facial nerve function. CONCLUSION: This approach is a modification of the Goel procedure in which the facial nerve from the tympanic segment to the cisternal segment was totally mobilized. Our procedure carries less risk to the facial nerve function than the Goel procedure and provides sufficiently wide exposure of clival lesions.

Pituitary apoplexy causing internal carotid artery occlusion--case report.

A 50-year-old man presented with pituitary apoplexy resulting in internal carotid artery occlusion manifesting as sudden onset of severe headache, right ptosis, and left hemiparesis, associated with visual impairment. Computed tomography showed a nodular mass, located in the sellar and suprasellar regions with early signs of acute cerebral ischemia. Magnetic resonance (MR) imaging indicated that the mass compressed the bilateral cavernous sinuses, resulting in obliteration of the cavernous portion of the right internal carotid artery. Right middle cerebral artery territory infarction was also found. Conservative therapy with steroids was given in the acute stage and repeated MR imaging showed recanalization of the internal carotid artery with reduction of the tumor size. The tumor was removed through the transsphenoidal approach to obtain a definitive diagnosis in the chronic stage. The histological diagnosis was consistent with non-functioning pituitary adenoma. Eye movement of this patient showed full recovery after the operation. Pituitary apoplexy resulting in internal carotid artery occlusion is rare. Surgical decompression through the transsphenoidal approach is appropriate, but the optimal timing should consider severe disturbance of visual acuity and visual field in the acute stage.

Surgery of spinal nerve sheath tumors originating from C1 or C2 of high cervical spine.

Spinal nerve sheath tumors (NSTs) originating from the C1 or C2 level are unique from both anatomical and clinical perspectives. Surgical technique to accomplish radical but safe resection of these tumors is described in 8 cases treated during the past 5 years. Surgical measures included positioning the patient in the lateral oblique position, unilateral posterior approach, exposure of the tumor along the surgical plane of the dural or perineural boundary, and proximal and distal amputation of the tumor with resection of dural penetration. Excessive bone resection and soft tissue manipulation were unnecessary. Microscopic complete removal of the tumor was accomplished in seven of eight cases. Subtotal resection was done in one case where the tumor extended beyond the vertebral artery. Functional assessment demonstrated satisfactory improvement after surgery in all cases. Surgery-related complications were not encountered in any case. Exposure of the tumor along the surgical plane of the dural or perineural boundary may be the key procedure required to accomplish radical but safe resection of spinal NSTs originating from the C1 or C2 level.

Focal adhesive arachnoiditis of the spinal cord: Imaging diagnosis and surgical resolution.

BACKGROUND: Although adhesive arachnoiditis of the spinal cord can cause progressive symptoms associated with syringomyelia or myelomalacia, its surgical resolution based on the imaging diagnosis is not well characterized. This study aims to describe the use of imaging for the diagnosis of focal adhesive arachnoiditis of the spinal cord and its surgical resolution using microsurgical arachnoidolysis. MATERIALS AND METHODS: Four consecutive patients with symptomatic syringomyelia or myelomalacia caused by focal adhesive arachnoiditis underwent microsurgical arachnoidolysis. Comprehensive imaging evaluation using constructive interference in steady-state (CISS) magnetic resonance imaging (MRI) or myelographic MR imaging using true fast imaging with steady-state precession (TrueFISP) sequences was included before surgery to determine the surgical indication. RESULTS: In all four patients a focal adhesion was identified at the cervical or thoracic level of the spinal cord, a consequence of infection or trauma. Three patients showed modest or minor improvement in neurological function, and one patient was unchanged after surgery. The syringomyelia or myelomalacia resolved after surgery and no recurrence was noted within the follow-up period, which ranged from 5 months to 30 months. CONCLUSIONS: MRI diagnosis of focal adhesive arachnoiditis is critical to determine the surgical indication. Microsurgical arachnoidolysis appears to be a straightforward method for stabilizing the progressive symptoms, though the procedure is technically demanding.

Primary epidural peripheral primitive neuroectodermal tumor of the thoracic spine.

A 25-year-old male patient presented with an extremely rare primary spinal peripheral primitive neuroectodermal tumor (pPNET) manifesting as acutely progressive paraparesis and back pain. Neuroimaging and intraoperative examination showed that the tumor was confined to the epidural space of the thoracic spine. The patient was treated successfully by gross total resection of the tumor followed by chemotherapy and local radiotherapy. The present case illustrates the unexpected occurrence and important differential diagnosis of primary epidural pPNET of the thoracic spine in young patients presenting with progressive paraparesis and back pain.

[Enlarged perivascular spaces associated with hydrocephalus: a case report].

We report a case of enlarged perivascular spaces (EPVS) in the mesencephalothalamic region associated with hydrocephalus. EPVS are extensions of the subarachnoid space that accompany penetrating arteries and may cause mass effects. A 56-year-old woman with EPVS-associated hydrocephalus underwent third ventriculostomy and biopsy. We compared pre-and postoperative images by magnetoencephalography (MEG) and tractography, and evaluated the effects of EPVS. These images were useful to determine the patient' s condition.

[A case of spontaneous fusiform aneurysm in a middle cerebral artery branch which causes rapidly thrombosed formation in a short period].

A 61-year-old man presented with the complaint of headache. Investigations revealed a fusiform middle cerebral artery aneurysm at the M2 part. The formation of the aneurysm rapidly developed to a partially thrombosed aneurysm in the course of four months. As regards the treatment of the aneurysm, at first we tried surgery with a superficial temporal artery middle cerebral artery bypass (STA-MCA bypass) and trapping of the aneurysm. However, during the procedure, it was difficult to control bleeding from the temporal muscle, bone flap, and subdural space. Because of this, we finished the STA-MCA bypass without trapping of the aneurysm and then, four days later, we confirmed bypass patency and treated the aneurysm using endovascular coil embolization. Based on both surgical and interventional investigations in this case and a review of the reported literature, the authors propose that there are two mechanisms causing the middle cerebral artery fusiform aneurysm to develop thrombosed formation rapidly: (i) Peripheral middle cerebral artery branches demand less blood flow than other major trunk arteries. (ii) Bypass flow maintains perfusion to the distal branches. On the other hand, this flow alteration caused by surgical vascular bypass may promote the development of the aneurysm to thrombosed formation. The treatment of a fusiform middle cerebral artery aneurysm at the M2 part is also discussed.

[A case of amnesia caused by a falx meningioma in the right frontal region].

A 60-year-old right-handed man suffered frontal lobe dysfunction caused by a falx meningioma. He appeared to have amnesia and left hemiparesis. It is note-worthy that he had a lesion of the right frontal region but exhibited both verbal and non-verbal memory impairment, although his intelligence, remote memory and digit span were normal. Computed tomography and magnetic resonance imaging revealed a falx meningioma in the right frontal lobe including the right cingulate gyrus and corpus callosum. Single photon emission CT revealed a wide area of low perfusion surrounding the right frontal lobe including the cingulate gyrus. After surgery, left hemiparesis and amnesia disappeared. SPECT after surgery showed an area of low perfusion limited to the right frontal region. We concluded that the amnesia in this case might be caused by the interruption of hippocampal input into the cingulate gyrus.