The dose-related effects of single focal irradiation on the medial temporal lobe in rats were investigated by sequential magnetic resonance imaging and histological examination. Irradiation of 200 Gy as a maximum dose using 4mm collimators with a gamma unit created an area of necrosis consistently at the target site within 2 weeks after irradiation. Irradiation of 100 Gy caused necrosis within 10 weeks, and 75 Gy caused necrosis within one year. Irradiation of less than 50 Gy did not induce necrosis consistently, although a restricted area of necrosis was created in the medial temporal structures including the intraparenchymal portion of the optic tract. 75 Gy may be the optimum dose for creating necrosis consistently in the medial temporal lobe structures. However, careful dose planning considering both dose-time and dose-volume relationships in necrosis development is necessary to avoid injury to vulnerable neural structures such as the optic tract when applying radiosurgical techniques to treat functional brain disorders in medial temporal lobe structures such as temporal lobe epilepsy.
Intraoperative ultrasonography (IOUS) was used to evaluate the location and compressive effects of intraspinal fragments in thoracolumbar fractures and the efficacy of reduction maneuvers in patients operated on for isolated or attached intraspinal fragments or for global posterior wall disruption. Dynamic IOUS was used to evaluate the effects of traction and lordosis. Fifty-eight patients were evaluated using a 7.5 MHz ultrasound probe, including 27 treated by impaction, 19 by removal of apparently isolated fragments, and 12 by traction followed by lordosis for global posterior wall disruption. IOUS had limitations and problems caused by split fragments and residual pedicular attachments that can compromise intraoperative maneuvers. The risk of secondary displacement of isolated fragments treated by impaction was very high. In particular, the pinching effect produced by T-shaped fractures was commonly responsible for secondary displacement. IOUS evaluation of canal clearance after fragment removal was satisfactory, but did not provide quantitative data. IOUS was easier to perform and apparently more reliable than intraoperative myelography. The dynamic IOUS data suggest that, except for severely tilted fragments that are completely free or remain attached to a pedicle, residual discal attachments significantly influence the likelihood of successful reduction.
To clarify whether epilepsy surgery improves cerebral metabolism, pre- and postoperative positron emission tomography (PET) scans were performed, with special reference to hypometabolism outside the resected epileptogenic zones in nine patients (8 males, 1 female) with medically intractable complex partial seizures and multiple hypometabolic zones. Seven patients underwent unilateral anterior temporal lobectomy, one patient underwent selective amygdalohippocampectomy, and one patient underwent parieto-occipital cortical resection and anterior temporal lobectomy. PET scans were obtained at least 6 months after surgery. Eight patients became seizure-free, and one patient had fewer than three seizures per year. Four patients showed improved glucose metabolism in the formerly hypometabolic zones, which were remote to the surgical site and ipsilateral to the epileptogenic foci. Five patients, who showed bilateral temporal hypometabolism preoperatively, had contralateral temporal hypometabolism after surgery. The relative glucose uptake in four of these patients showed increased metabolism of the adjacent lobes ipsilateral to the surgical site. The lobes that showed increased glucose metabolism after surgery were mostly frontal. Hypometabolism is reversible in the ipsilateral remote area, and may be caused by inhibition via the intercortical pathway. Contralateral temporal hypometabolic zones that persist after surgery may be caused by a different mechanism, and neither indicate the presence of seizure foci nor affect the seizure outcome.
A 41-year-old female presented with a rare case of bilateral vertebral artery occlusion following C5-6 cervical spine subluxation after a fall of 30 feet. Digital subtraction angiography showed occlusion of the bilateral vertebral arteries. Unlocking of the facet joint, posterior wiring with iliac crest grafting, and anterior fusion were performed. The patient died on the 3rd day after the operation. This type of injury has a grim prognosis with less than a third of the patients achieving a good outcome.
A 75-year-old male was hit by a car, when riding a bicycle. The diagnosis of acute epidural hematoma was made based on computed tomography (CT) findings of lentiform hematoma in the left temporal region. On admission he had only moderate occipitalgia and amnesia of the accident, so conservative therapy was administered. Thirty-three hours later, he suddenly developed severe headache, vomiting, and anisocoria just after a positional change. CT revealed typical acute subdural hematoma (ASDH), which was confirmed by emergent decompressive craniectomy. He was vegetative postoperatively and died of pneumonia one month later. Emergent surgical exploration is recommended for this type of ASDH even if the symptoms are mild due to aged atrophic brain.
A 60-year-old female and a 66-year-old male presented with post-traumatic pituitary apoplexy associated with clinically asymptomatic pituitary macroadenoma manifesting as severe visual disturbance that had not developed immediately after the head injury. Skull radiography showed a unilateral linear occipital fracture. Magnetic resonance imaging revealed pituitary tumor with dumbbell-shaped suprasellar extension and fresh intratumoral hemorrhage. Transsphenoidal surgery was performed in the first patient, and the visual disturbance subsided. Decompressive craniectomy was performed in the second patient to treat brain contusion and part of the tumor was removed to decompress the optic nerves. The mechanism of post-traumatic pituitary apoplexy may occur as follows. The intrasellar part of the tumor is fixed by the bony structure forming the sella, and the suprasellar part is free to move, so a rotational force acting on the occipital region on one side will create a shearing strain between the intra- and suprasellar part of the tumor, resulting in pituitary apoplexy. Recovery of visual function, no matter how severely impaired, can be expected if an emergency operation is performed to decompress the optic nerves. Transsphenoidal surgery is the most advantageous procedure, as even partial removal of the tumor may be adequate to decompress the optic nerves in the acute stage. Staged transsphenoidal surgery is indicated to achieve total removal later.
A 54-year-old female presented subarachnoid hemorrhage from an aneurysm arising from the anterior (dorsal) wall of the internal carotid artery (ICA). During four-vessel angiography, an extravasated saccular pooling of contrast medium emerged in the suprasellar area unrelated to any arterial branch. The saccular pooling was visualized in the arterial phase and cleared in the venophase during every contrast medium injection. We suspected that the extravasated pooling was surrounded by hard clot but communicated with the artery. Direct surgery was performed but major premature bleeding occurred during the microsurgical procedure. After temporary clipping, an opening of the anterior (dorsal) wall of the ICA was found without apparent aneurysm wall. The vessel wall was sutured with nylon thread. The total occlusion time of the ICA was about 50 minutes. Follow-up angiography demonstrated good patency of the ICA. About 2 years after the operation, the patient was able to walk with a stick and to communicate freely through speech, although left hemiparesis and left homonymous hemianopsia persisted. The outcome suggests our treatment strategy was not optimal, but suture of the ICA wall is one of the therapeutic choices when premature rupture occurs in the operation.
A 72-year-old male presented with a primary hemangioblastoma of the posterior fossa with unusual dural attachment and meningeal arterial blood supply from the external carotid artery and marginal tentorial artery. Preoperative embolization facilitated complete resection of the tumor with no resultant neurological deficit. Hemangioblastoma must be included in the differential diagnosis of tumors with dural involvement. Preoperative embolization is very useful in such tumors.
A 50-year-old female presented with primary intracranial squamous cell carcinoma (SCC) at the right cerebellopontine angle manifesting as right facial nerve paresis. She had undergone gross total removal of a right cerebellopontine angle epidermoid cyst 10 years before and had done well until recently. Magnetic resonance imaging showed a heterogeneous tumor with markedly enhanced irregular margin. Subtotal removal of the tumor was achieved. Histological examination showed moderately differentiated SCC. After surgery, she underwent chemotherapy and gamma radiosurgery. She is now well 5 years after the diagnosis of SCC.
The ostium of the recipient artery and the orifice of the donor artery must be clearly visualized for the establishment of microvascular anastomosis. Specially designed colored flexible cylindrical or T-shaped silicone rubber stents were made in various sizes (400 or 500μm diameter and 5mm length) and applied to bypass surgery in patients with occlusive cerebrovascular disease such as moyamoya disease and internal carotid artery occlusion. The colored flexible stents facilitated confirmation of the ostium of the artery even in patients with moyamoya disease and allowed precise microvascular anastomosis without problems caused by the stent.
The Committee of Brain Tumor Registry of Japan (1996-1997) Classification of Tumor Sites and Histology for the Registry 1) Sites of Tumor 2) Classification of Histology Part I General Features of Brain Tumors 1. Total Registered Number 1) Numbers of Primary and Metastatic Brain Tumors 2) Age Distribution of Primary Brain Tumors (1969-1990) 3) Annual Trend of Frequency of Brain Tumors by Age Distribuion 2. Frequency of Primary Brain Tumors 1) Frequency of Tumors by Histology (1969-1990) 2) Frequency of Tumors by Histology (1984-1990) 3) Frequency of Tumors by Histology in Children (1984-1990) 4) Age and Sex Distribution of Primary Brain Tumors in Children (1984-1990) 5) Location of Tumor Origin (Except Meningioma) [1984-1990] 6) Location of Tumor Origin: Meningioma [1984-1990] 7) Location of Tumor Origin: Various Tumors [1984-1990] 3. Metastatic Brain Tumors: 1984-1990 1) Age Distribution of Metastatic Tumors 2) Location of Metastases 3) Frequency of Tumors by Primary Cancer 4) Mode of Treatment for Brain Metastases Part II Results of Treatments Computation of Relative Survival Rate Definition of Various Classifications of Gliomas 1. Relative Survival Rate 1) Relative Survival Rate (1986-1990): Various Brain Tumors 2) Relative Survival Rate (1969-1980): Relatively Rare Tumors 3) Relative Survival Rare (1981-1990): Relatively Rare Tumors 2. Relative Survival Rate of Primary Brain Tumors (Operation, Radiation, Chemotherapy) 1) Craniopharingioma 2) Germinoma 3) Malignant Glioma 4) Glioblastoma 5) Benign Glioma 6) Astrocytoma 7) Malignant Astrocytoma 8) Medulloblastoma 9) Oligodendroglioma 3. Relative Survival Rate by Age:1981-1990 1) All Glioma 2) Glioblastoma 3) Astrocytoma 4) Malignant Astrocytoma 4. Results of Treatments for Metastatic Brain Tumors: 1981-1990 1) Primary Site and Survival Rate 2) Radiation Therapy 3) Extent of Cancer and Survival Rate 4) Meastasis to Other Organ and Survival Rate 5) Operation with or without Radiation Therapy