[A case of a lumbar spinal synovial cyst located on the midline].

We report a case of lumbar spinal synovial cyst located on the midline. A 72-year-old man was admitted to our hospital with the chief complaint of low back pain radiating to the left buttock and posterior thigh. An MR image revealed an extradural cystic lesion adjacent to the dorsal side of the dural sac at the L4-5 level. The cyst was remote from the facet joints and existed on the midline just in front of the L4 lamina. A CT scan showed a concave deformity of the ventral aspect of the L4 lamina because of compression by the cyst. The patient underwent L4 laminectomy and total removal of the cyst. The cyst was in contact with the anterior surface of the ligamentum flavum and it had no connection with the facet joint. In the histological examination, the cyst was multilobular and lined with synovial epithelium. Therefore the cyst was diagnosed as a synovial cyst. After the operation, the pain radiating to the buttock and thigh completely disappeared. Intraspinal synovial cysts are usually located in the lower lumbar spine and most of them are adjacent to the facet joint. The cysts that are located on the midline are very rare. We review previous reports and discuss clinical and pathological features of spinal synovial cysts.

Severe subarachnoid hemorrhage during transsphenoidal surgery for pituitary adenoma.

There are many reports about complications of transphenoidal surgery for pituitary adenomas. We report a patient who suffered severe subarachnoid hemorrhage due to an indirect injury of the intradural internal carotid artery during or immediately after transsphenoidal surgery for pituitary adenoma. An autopsy suggested that a small branch of the intradural internal carotid artery was strongly adherent to the suprasellar portion of the tumor capsule and its avulsion from the internal carotid artery might have been caused as the capsule fell down during the intracapsular removal of the tumor. In a case of pituitary adenoma operated by the transsphenoidal approach the possibility of subarachnoid hemorrhage due to this type of arterial injury, though rare, should be kept in mind.

[Sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment; a case report].

A case of sphenoid sinus aspergillosis presenting abducens nerve palsy and visual field impairment is reported. A 73-year-old woman visited our hospital with the complaint of head heaviness on the 27th of March, 1989. Although results of neurological examinations were normal, craniogram revealed the destruction of the clivus, and CT scan and MRI showed a mass lesion, which was thought to be a mucocele in the sphenoid sinus. On the 1st of September, she developed right abducens nerve palsy and visual field impairment. MRI performed on the same day showed an enlargement of the mass lesion in the sphenoid sinus. In order to decompress the involved cranial nerves, her sphenoid sinus was explored on the 22nd of September. The sphenoid sinus was filled with purulent fluid and yellowish mass. Histopathological examination revealed colonies of aspergillus fumigatus. Fluconazole, a new antifungal drug, was given for 34 days postoperatively. The right abducens nerve palsy and the visual field impairment gradually improved along with a reduction of the mass lesion in her sphenoid sinus. Sphenoid sinus aspergillosis is a rare disease. Its diagnosis is difficult. However, MRI can show a specific low signal intensity in T2-weighted image. Also in our case, MRI on the first admission showed a definite low signal intensity in some parts of the lesion, which exhibited a high intensity later on during the second administration, probably due to a qualitative change. To our knowledge, only 33 such cases have been previously reported. Intracranial involvement occasionally occurs in this disease. In its early stage, cranial nerve palsies are caused by nerve compression or invasion by this disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Dural arteriovenous malformation in the cervical spine presenting with subarachnoid hemorrhage: case report.

Most spinal dural arteriovenous malformations are located in the thoracic and lumbar regions. The symptoms include pain, weakness, sensory disturbances, and sphincter dysfunction, which are usually gradual in onset. They are attributed to venous hypertension with a resultant ischemia of the cord, and hemorrhage from them is rare. The authors report an unusual case of a patient with a dural arteriovenous malformation in the cervical spine who was admitted with a sudden onset of severe headache and dysesthesia due to subarachnoid hemorrhage.

Rotatostereoradiography: a new radiodiagnostic method--development of a new three-dimensional radiodiagnostic device and evaluation in neurosurgical clinics.

The rotatostereoradiographic device uses an x-ray tube coupled with an image intensifier rotating through a 180 degree arc in 2.25 seconds. The rapidly rotating x-ray tube allows 180 degree-arc angiograms to be obtained with a single injection of contrast medium. Subtracted fluoroscopic angiograms can be viewed immediately after injection of the contrast medium with digital recording. These three-dimensional images are displayed on side-by-side monitors stereoscopically. The mortality and morbidity of subarachnoid hemorrhage can only be greatly reduced by surgical treatment of unruptured aneurysms and arteriovenous malformations detected by a wide survey of subarachnoid hemorrhage. Such a wide survey would be possible utilizing intra-arterial digital subtraction angiography via the ascending aorta and this new three-dimensional radiodiagnostic method. A fluoroscopic device must be used to allow easier manipulation of the catheter from the axillary or brachial artery.

Lithium ion does not protect brain against transient ischemia in gerbils.

It has been proposed that lithium ion desensitizes neuronal receptors that function via the inositol phospholipid signaling mechanism. We examined the effects of lithium chloride on the morphologic outcome after 5 minutes of cerebral ischemia induced in gerbils by occluding both common carotid arteries under brief halothane anesthesia. In three treated groups of 10 gerbils each, 5 meq/kg i.p. lithium chloride was given 2 days, 1 day, and 2 hours before ischemia; 2 hours before ischemia; or immediately after the end of ischemia. Corresponding control groups of nine or 10 gerbils each received equivalent volumes of saline injected at comparable times. All gerbils were perfusion-fixed 1 week later, and neuronal density of the hippocampal CA1 pyramidal cells was determined. Lithium induced very mild intraischemic systemic hypothermia, but postischemic hyperthermia developed in both treated and control groups. Neuronal densities were equal in corresponding groups. The results indicate that our regimen of lithium administration provides no benefit in survival of hippocampal neurons, and intraischemic hypothermia of less than 0.8 degrees C is not protective. Other strategies to inactivate the signal transduction system that is specific for excitatory neurotransmission should be evaluated.

[Development of all-silicone detachable balloons].

Treatment of cerebral vascular lesions such as carotid cavernous sinus fistulas and giant aneurysms is now being performed with intravascular detachable balloon embolization techniques. We have developed several types of all-silicone detachable balloons. Our balloons have self-sealing valves (with or without collars) and detach with simple traction. The self-sealing valve is smaller than 0.6 mm and the balloon can easily be placed through a 7-F catheter. We started clinical trials and a representative case was reported.

[Studies on the operative factors affecting the reduction of chronic subdural hematoma, with special reference to the residual air in the hematoma cavity].

The authors previously reported the effect of preoperative factors affecting the reduction of chronic subdural hematoma. In this report, we evaluated some operative factors, including operative methods, duration of drainage, and residual air volume, with newly developed CT volumetry technique. As described before, the hematoma volume reduces exponentially. An exponential curve was fitted to the reduction curve using the least square method, and its half reduction days (HRD) was calculated. This HRD represents a mathematical indicator of the reduction rate of CSDH. Using this technique, the relationship between this HRD and operative method, the duration of drainage and the volume of the postoperative residual air were examined in 61 patients. Operative method (burr hole or small craniotomy) has no correlation with HRD. The duration of drainage also has no correlation. However, the volume of the residual air was highly correlated with the reduction rate of hematoma (r = 0.430; p less than 0.01). These results suggest that the residual air in the hematoma cavity may delay the reduction rate of the hematoma. Based on these results, the authors pay attention to the following points; 1) Less invasive burr hole method should be selected. 2) Patient's head position should be controlled to make the burr hole at the highest level in the operative field. 3) Hematoma cavity should be filled with saline as much as possible. 4) The inner membrane should never be injured, as it may cause tension pneumocephalus. Moreover, the drainage of cerebrospinal fluid may reduce the counter pressure and it leads to the delay of the hematoma reduction.

[Studies of the factors affecting the reduction of chronic subdural hematoma: effect of preoperative factors with special reference to cerebral atrophy].

The authors examined the preoperative factors affecting the reduction of chronic subdural hematoma (CSDH). A new method was developed to calculate the reduction rate of CSDH using CT volumetry technique. Postoperative serial CT films were examined and each hematoma volume was calculated by microcomputer. A postoperative exponential decrease of hematoma volume was observed, and the log-transformation of the hematoma volume turned the curve to a linear decrease. The least square method was used to fit an exponential curve, and the half reduction date (HRD) was calculated from the fitting curve. This HRD represents a mathematical indicator of the reduction rate of CSDH. Using this technique, the relationships between this HRD and the following parameters were examined in 61 patients. The preoperative factors examined are as follows; 1) patient's age, 2) preoperative hematoma volume, 3) CT number of the hematoma, 4) time interval between the head injury and the onset of symptom, and 5) the degree of cerebral atrophy. The degree of cerebral atrophy was calculated by means of a simple approximate formula as described by one of the authors (K.N.). Patient's age and the hematoma volume were correlated with HRD, and the correlation coefficients were 0.346 (p less than 0.01) and 0.298 (p less than 0.05) respectively. On the other hand, preoperative CT findings and the duration from the trauma had no correlation with HRD. Cerebral atrophy has hitherto been thought to affect the reduction of hematoma. However, our quantitative study revealed no correlation between cerebral atrophy and the reduction of hematoma rate. This unexpected result may be attributed to the difference between cerebral atrophy and cerebral elasticity.(ABSTRACT TRUNCATED AT 250 WORDS)

[Clinical application of microfibrillar collagen hemostat (Avitene) in neurosurgical field].

Microfibrillar collagen hemostat (Avitene) is a new absorbable hemostatic agent, of which mechanisms are adhesion to the bleeding site and platelet aggregation. Histopathological examinations revealed that Avitene was biocompatible with cerebral cortex in an animal experiments. Our previous studies indicated that Avitene is very effective and safe to use as a topical hemostatic agent during craniotomy in an experimental animal. Avitene was used as a topical hemostatic agent during craniotomy in 36 patients with intracranial organic lesions. Its effectiveness of hemostasis was revealed in 95%. This agent was especially useful to prevent oozing during craniotomy. Side effect of this agent was not reported in this study. Therefore, Avitene is very effective and safe to use as a topical hemostatic agent in the neurosurgical field.

[Sequential magnetic resonance images of a case of cerebral sinus thrombosis--imaging of the thrombosed sinus and its recanalization].

Magnetic resonance images of a case of superior sagittal sinus thrombosis before and after complete recanalization are presented. The patient was a 61-year-old man with two days history of intermittent right hemiconvulsion followed by post-ictal hemiplegia. Mild erythrocytosis was noted on admission. CT scans revealed left frontal hemorrhagic infarction with empty delta sign in the middle portion of the superior sagittal sinus. Left carotid angiogram showed occlusion of two frontal cortical veins and retrograde filling of these veins into the cavernous sinus. Lack of filling of the middle and anterior part of the superior sagittal sinus was noted. These studies led to the diagnosis of superior sagittal sinus thrombosis associated with hemorrhagic infarction. He was treated with intravenous infusion of low molecular dextran and venesection. Neither heparin, urokinase, hyperosmolar solutions nor steroids were used because of the presence of hemorrhagic infarction and of the lack of signs of increased intracranial pressure. He completely recovered neurologically and recanalization of the superior sagittal sinus was confirmed angiographically eight weeks after the onset. Magnetic resonance images were taken with a Siemens 1.5 T Magnetom scanner using spin-echo pulse sequences. A T 1-weighted mid-sagittal magnetic resonance image ten days after the onset showed hyperintensity in the middle part of the superior sagittal sinus which corresponded to the thrombus. Both T 1 and T 2 weighted coronal images revealed a small area of hypointensity indicating the existence of residual blood flow in the superior sagittal sinus in addition to the thrombus both in the sinus and in the cortical vein.(ABSTRACT TRUNCATED AT 250 WORDS)

[Tuberculoma and tuberculous meningitis mimicking metastatic brain tumor and meningeal carcinomatosis--case report].

A 45-year-old man was well until February 1986, when he experienced gait disturbance and psychiatric symptoms. On February 11 he fell down several times and developed generalized convulsion on the following day. He was admitted to a hospital in a delirious condition. The chest X-ray film showed infiltration in the left upper lobe, but computed tomographic (CT) scan of the head revealed no abnormality. Cerebrospinal fluid obtained by lumbar puncture contained 155 cells/mm3, all of which were lymphocytes, and protein and glucose concentrations were 372 mg/dl and 68 mg/dl respectively. In spite of negative smear tests of sputum and cerebrospinal fluid for tubercle bacilli he was administered antituberculosis drugs on the suspicion of pulmonary tuberculosis and tuberculous meningitis. His level of consciousness gradually returned to normal but the follow-up CT scans showed a low density area with contrast enhancement in the right thalamus and obliteration of the right quadrigeminal cistern which was also enhanced with contrast medium. He was transferred to our hospital on March 28 for further evaluation. On admission to our hospital he was alert and oriented, his pupils were equal and reactive to light and he had mild left hemiparesis, left hyperreflexia and left hemihypesthesia. Cell count of the cerebrospinal fluid was 243/mm3, 90% of which were lymphocytes and protein and glucose contents were 340 mg/dl and 42 mg/dl respectively. Both smear and culture of the cerebrospinal fluid were negative for tubercle bacilli and other organisms. Cytological examination of the cerebrospinal fluid demonstrated clusters of cells of various sizes with high N/C ratio which suggested these cells were malignant.(ABSTRACT TRUNCATED AT 250 WORDS)

[Chondromyxoid fibroma of the skull base extending from the middle fossa to the posterior fossa--case report].

An extremely rare case of chondromyxoid fibroma of the skull base extending from middle fossa to posterior fossa is reported. The patient is a forty-seven year old woman who became paranoiac four months before admission and her gait was unsteady for one month. On April 27th, 1985, she fainted and was admitted to Kanto Rosai Hospital on April 30th. She was drowsy and disoriented. Neurologic examination revealed left pyramidal tract signs and impaired functions of right Vth (first and second branches), VIth and VIIIth cranial nerves. She was anemic and bleeding tendency due to thrombocytopenia was also recognized. Hematologist's diagnoses were myelodysplastic syndrome plus iron deficiency anemia. Neuroradiologic studies including CT scan, cerebral angiographies and MRI revealed a huge extra-axial skull base tumor extending from middle fossa to posterior fossa completely destroying the skull base. Stenosis of cavernous portion of internal carotid artery due to tumoral involvement was also noted. Surgical excision of the tumor was performed three weeks after the admission with the use of platelet transfusion. Transpetrosal transtentorial approach was performed removing the intracranial part of the tumor which was a semi-translucent jelly-like soft mass. The patient had a good post-operative course and improvement in the neurologic condition was recognized. Microscopically, the tumor showed marked lobular formation with small vessels and fibroblasts in the periphery of the lobule. The fibroblasts took stellate figures in the myxoid matrix at the center of the lobule. Chondroid pattern was also observed. Mitosis and nuclear atypism were not observed. Histological diagnosis was chondromyxoid fibroma.(ABSTRACT TRUNCATED AT 250 WORDS)

[The effectiveness of dynamic CT as a tool for the analysis of cerebral hemodynamics].

It is generally accepted that dynamic CT is one of the best way to evaluate cerebral hemodynamics. Employing our original computer simulation method, the present study was undergone to examine the theoretical background of dynamic CT. When a single bolus injection of non-diffusable indicator is intravenously performed, the time density curve of a cerebral tissue consists of the following two components: the time density curve of a carotid artery (g(x)) and the dispersion curve through the cerebral tissue (f(x)). A mean transit time (MTT) of the latter curve can be mathematically calculated by height-over area method. The concept gave us an interesting idea that a computer simulation could produce the time density curve implying an MTT. Convolution technique was applied to synthesize it from f(x) and g(x). The latter curve (g(x)) is influenced by several conditions such as a dispersion through a lung, a cardiac output and systemic arterial pressure. Therefore, it is not essential to measure the definite parameter from the time density curve obtained by dynamic CT. Dynamic CT should be considered as a qualitative method rather than a quantitative one. Several parameters were given by the analysis of a simulated curve. A time to peak (PT), above all, was most linearly correlated to MTT. A prolongation of PT in the insulted area, which means a prolongation of MTT, leads to a decrease of cerebral blood flow. In addition, we examined if Gamma variate fitting curve could apply a substitute for an original time density curve.(ABSTRACT TRUNCATED AT 250 WORDS)

[Spontaneous disappearance of cerebellopontine angle arachnoid cyst: report of a case].

A case of a cerebellopontine angle arachnoid cyst spontaneously disappeared is reported. A 1-year-and-11-month old boy was suffered from sudden onset of left facial palsy. CT scan demonstrated dilatation of left internal auditory canal and a cystic lesion in the left cerebellopontine angle. Neurological examination disclosed only left facial palsy and left hearing loss. There was no signs and symptoms of increased intracranial pressure. He was followed up by CT scan. Repeated CT scan showed non-enhanced cystic lesion, the attenuation value of which was similar to that of cerebrospinal fluid. The cyst expanded gradually, and the brain stem was severely compressed. Then operation was planned under the diagnosis of left cerebellopontine angle arachnoid cyst about 2 years after the onset. But CT scan performed before operation showed disappearance of the cyst. Without operation the patient was followed by CT scan. There is no recurrence of the cyst. Natural history of arachnoid cyst will be well understood with repeated CT scan.

A quantitative study of physiological cerebral atrophy with aging. A statistical analysis of the normal range.

A new method of discriminating pathological cerebral atrophy from physiological atrophy during aging is reported. The authors advocate a pixel counting method using a minicomputer for the quantitative measurement of cerebral atrophy. Five hundred cases were studied with this quantitative method and the normal range of the physiological atrophy was determined statistically. In order to estimate the degree of cerebral atrophy easily, the conventional linear measurement methods were compared with the pixel counting method using multivariant analysis, and a simple formula for the calculation of the degree of cerebral atrophy is proposed. Using this formula and the normal range, pathological cerebral atrophy is easily detectable.

[The normal range of cerebral atrophy during aging: statistical analysis of 500 normal subjects].

We previously reported the newly developed quantitative measurement of the cerebral atrophy (pixel count method), and advocated the value CCR (CSF-cranial ratio) as the index of the volumetric measurement of the cerebral atrophy. As the pixel count method is somewhat troublesome, we tried to compare the various linear measurement methods with pixel count method by means of multivariant analysis, and reported a single formula to calculate CCR from the linear measurement methods. Now we studied 500 normal subjects using the pixel count method and examined the normal range of the cerebral atrophy during aging by means of the maximum likelihood method. The normal range was estimated as follows; 0.32 less than y less than 5.78 (t less than 48), 0.068 t--2.944 less than y less than 0.368 t--11.884 (t greater than 48). Using these formula and this newly reported normal range, we can easily predict whether the cerebral atrophy is pathological or not.

Radiopaque synthetic sponge as a prosthesis for microvascular decompression. Technical note.

A radiopaque synthetic sponge is proposed as a prosthesis for microvascular decompression. Displacement of the prosthesis can be easily detected on a plain x-ray skull film.