Programmable shunt valves: in vitro assessment of safety of the magnetic field generated by a portable game machine.

Cerebrospinal fluid (CSF) shunts are frequently used to treat hydrocephalus. The use of a programmable shunt valve allows physicians to easily change the opening pressure. Since patients with adjustable CSF shunt valves may use portable game machines, the permanent magnets in these machines may alter the shunt valve programmed settings or permanently damage the device. This study investigated the risk of unintentional valve adjustment associated with the use of game machines in patients with programmable CSF shunt valves. Four adjustable valves from 4 different manufacturers, Sophysa Polaris model SPV (Polaris valve), Miethke proGAV (proGAV), Codman Hakim programmable valve (CHPV), and Strata II small valve (Strata valve), were evaluated. Magnetic field interactions were determined using the portable game machine, Nintendo DS Lite (DS). The maximum distance between the valve and the DS that affected the valve pressure setting was measured by x-ray cinematography. The Polaris valve and proGAV were immune to unintentional reprogramming by the DS. However, the settings of the CHPV and Strata valves were randomly altered by the DS. Patients with an implanted shunt valve should be made aware of the risks posed by the magnetic fields associated with portable game machines and commonly used home electronics.

Electromagnetic field system for transsphenoidal surgery on recurrent pituitary lesions - technical note.

BACKGROUND: Post operative scar tissue makes transsphenoidal surgery for recurrent pituitary lesions very difficult. However, with the use of a new cautery system, known as the EMF system, we were able to perform the surgical procedures with relative ease. In this article, we report the advantages and clinical applications of this new instrument in transnasal reoperation. METHODS: The EMF system generates a high frequency current of 13.56 MHz that is focused on the target. This enables it to coagulate, cut, and vaporize tissue in a pinpoint fashion. The bayonet and pencil-type hand pieces of the EMF system are slim, and the tips of the probe are flexible. This enables the surgeon to easily reach deep narrow spaces. We have used the EMF system for transsphenoidal surgery on recurrent pituitary lesions in 18 patients. The system was used to cut and vaporize scar tissue and vaporize firm and fibrotic tumor tissue. RESULTS: During surgery, the system could easily cut and vaporize scarred tissues in the nasal cavity, the sphenoid sinus, and the sella, without damage to the surrounding tissue. In addition, in 3 patients who had extremely fibrotic and firm tumors, we were able to easily vaporize the tumor with safety. CONCLUSIONS: The EMF system enables the surgeon to cut and vaporize tissue with ease and with minimal injury to the surrounding structures. It was particularly valuable in the resection of firm tumors. It may also shorten the operating time because of quick vaporization of the firm tissue.

[A case of a hemorrhagic non-functioning pituitary adenoma presenting with abducens nerve palsy].

A pituitary adenoma presenting with isolated abducens nerve palsy is an extremely rare occurrence. The authors report a rare case of a hemorrhagic non-functioning pituitary adenoma presenting with isolated abducens nerve palsy. The etiology of isolated abducens nerve palsy by a pituitary tumor is discussed. A 34-year-old male presented with severe headache, vomiting, right-sided ophthalmic pain, and diplopia. On admission, he had right-sided isolated abducens nerve palsy. Magnetic resonance (MR) images demonstrated a less-enhancing intra-and suprasellar mass lesion with intratumoral hemorrhage and right-sided slight cavernous sinus invasion, that exhibited an iso-high mixed intensity on T1-weighted image and a low-high mixed intensity on T2. Cerebral angiogram revealed no abnormality. The pituitary hormone function was within normal range. The tumor was totally resected via the transnasal route. The histological diagnosis was a typical non-functioning pituitary adenoma with hemorrhage. The abducens nerve palsy was completely resolved 7 months after surgery. It was supposed that the isolated abducens nerve palsy was caused by the direct compression of abducens nerve in the cavernous sinus by the extension of a pituitary tumor and hematoma. Pituitary adenoma should be considered in the differential diagnosis of abducens nerve palsy. Early diagnosis and transsphenoidal surgery is recommended to improve the abducens nerve palsy.

Clinicopathological examination of glioma by proton magnetic resonance spectroscopy background.

Automation of proton magnetic resonance spectroscopy (MRS) in recent years has made it possible for MRS measurement to be performed in a shorter time than before, and the number of reports of its usefulness for the assessment of glioma malignancy has been increasing in the past several years. We studied the efficacy of proton MRS when used for glioma and conducted clinicopathological examination of glioma. The subjects were 15 patients who had received a pathological diagnosis of glioma at our hospital (6 cases of glioblastoma, 1 case of anaplastic astrocytoma, 4 cases of low-grade astrocytoma, and 4 cases of radiation necrosis); Siemens Magnetom Vision 1.5T was used for the study. Regions of interest (ROIs) were defined as the areas where abnormal signals were found on magnetic resonance imaging (MRI). Areas of primary peaks, such as choline (Cho), N-acetylaspartate (NAA), and lactate (Lac), were measured, and the ratios to normal brain tissue were examined. This study revealed a tendency of increased malignancy of glioma with a decrease in NAA. Some cases also displayed a decrease in Cho with an increase in malignancy. Assessment of malignancy must not be based on a single ROI alone, but several ROIs should be assessed comprehensively. Measurement was difficult when the tumor volume was small. Because diagnosis of very early glioma by MRS seemed difficult, other adjunctive diagnoses may be necessary. Proton MRS is very useful for diagnosis of glioblastoma.

Gliomatosis cerebri in a young patient showing various cranial nerve manifestations: a case report.

A case of gliomatosis cerebri in a 27-year-old man showing various cranial nerve manifestations is described. He was diagnosed as having cranial mononeuritis multiplex (bilateral oculomotor nerve paralysis, left facial nerve paralysis, bulbar palsy manifestations, and hypoglossal nerve paralysis) and was hospitalized in the neurology department on August 1, 2000. Although he continued to visit the neurology department after discharge, his manifestations showed no improvement. He was sent to our department for brain biopsy in August 2001. A biopsy performed at the Sylvian fissure from the frontal lobe/temporal lobe cortex showed high intensity on T2-weighted and Flair magnetic resonance imaging (MRI). The pathological findings were diffuse low-grade astrocytoma infiltrating between the pia mater and the cerebral cortex. We believed that the astrocytoma spreading on the subpia mater was responsible for the various cranial nerve manifestations, and we started whole-brain irradiation (46 Gy) + interferon (IFN)-beta D.I.V. from September 2001. The pathological findings of the brain biopsy showed diffuse astrocytoma. The clinical presentation was dramatically improved after radiotherapy. It seemed that this tumor had spread along the subpia mater and subependyma. When he was discharged in early December, he walked by himself. The characteristic features of this case are that no lesion in the cerebellum or brain stem was found on MRI, even though the main manifestations were cerebello-brain stem manifestations, and biopsy of the cerebral cortex revealed astrocytoma. It should be noted that the clinical manifestations of astrocytoma in some cases are dissociated from the imaging observations.

Male prolactinoma with pituitary apoplexy concomitant with intracerebral hemorrhage--case report.

A 56-year-old male presented with a prolactin-secreting pituitary adenoma who suffered pituitary apoplexy associated with intracerebral hemorrhage of the caudate head and putamen. The centers of both the intratumoral hematoma and intracerebral hemorrhage appeared as hyperintense on T1-weighted and T2-weighted magnetic resonance imaging, indicating the subacute stage and probably similar timing of onset. The tumor was treated surgically 6 weeks after the onset. The causative factor for the apoplexy remains unclear.

Optic nerve decompression for orbitofrontal fibrous dysplasia.

Orbitofrontal fibrous dysplasia often involves the bony orbit and the optic canal. Although fibrous dysplasia reportedly produces compression of the optic nerve leading to visual distrubances, optic nerve decompression in patients without clinical signs of optic neuropathy is still controversial. We describe two patients with orbitofrontal fibrous dysplasia without signs of visual disturbance and one patient with McCune-Albright syndrome and progressive visual impairment. Optic nerve decompression was performed prophylactically for two patients and therapeutically for one patient through the transcranial extradural route. Dystopias and craniofacial deformities induced by fibrous dysplasia also were corrected. The micropressure suction-irrigation system was especially effective for decreasing heat transfer and thereby preventing thermal injury of the optic nerve. The orbitofrontal area was reconstructed from cranial bone, iliac bone, and ribs. Postoperative follow-up revealed no disturbances in visual function and no evidence of cerebrospinal fluid leakage. These findings suggest that optic nerve decompression may be effective in preventing visual disturbances with minimal risk of other neurological sequelae. Subsequent orbital reconstruction yielded satisfactory cosmetic results.