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Biomedical subjects

K Miyamachi

Publications and source records attributed to K Miyamachi.

16 recordsLinked to original sources
PubMed1997

Stereotactic irradiation without whole-brain irradiation for single brain metastasis.

PURPOSE: The effectiveness of stereotactic irradiation (STI) alone without whole-brain irradiation (WBI) for a single metastatic brain tumor was analyzed retrospectively. METHODS AND MATERIALS: Forty-four patients with this condition were treated using radiosurgery (RS) alone or fractionated stereotactic radiotherapy (FSR) without WBI. RESULTS: The initial response rate was 92% and the overall local control rate was 84% (37 of 44 patients). A total of 39% (18 of 44) of patients experienced intracranial relapse outside the initial target area. Forty-eight percent (21 of 44) of patients required salvage treatment for intracranial relapse. All 7 patients who received WBI as salvage treatment required no further salvage treatment, but 5 of the 14 patients who received salvage STI without WBI required three to four treatments for brain metastasis. Late radiation damage was not seen with initial treatment but was observed with retreatment. The overall median survival time was 261 days, with a standard error of 64 days. Actuarial survival at 12 and 24 months was 34% and 9%, respectively. The actuarial survival rate was significantly affected by the existence of active extracranial disease (p = 0.041). CONCLUSION: The high response rate and short treatment period of STI alone are advantageous in the treatment of single brain metastasis in patients with active extracranial disease with WBI reserved for relapse. Because of the low complication rate, STI alone may be also useful in patients with good prognosis, without extracranial disease.

Aged↗
PubMed1997

Full functional recovery after surgical repair of transected abducens nerve: case report.

OBJECTIVE AND IMPORTANCE: Results of surgical repair of the injured abducens nerve are rarely reported in the literature. A full functional recovery of a completely resected abducens root may be exceptional. We describe a patient who obtained normal ocular alignment and binocular vision after surgical reconstruction of a transected abducens nerve. CLINICAL PRESENTATION: A 56-year-old woman with a petroclival meningioma was presented. She underwent total removal of the tumor through a combined supra/infratentorial transpetrosal approach. The abducens nerve was tightly attenuated by the tumor and thickened dura. During dissection, the nerve was completely transected just behind the entrance to Dorello's canal. INTERVENTION: The abducens nerve was the single root type and inevitably required surgical repair. To obtain a sufficient length of the distal stump for trimming, part of the petrosphenoidal ligament was cut and the superior border of the petrous bone was exposed. The proximal stump of the nerve was also trimmed to obtain healthy tissue, and reconstruction was performed with five 10-0 nylon sutures. Five months later, esodeviation began to improve. Nine months after the surgery, the patient did not complain of diplopia and an objective assessment reported normal ocular alignment and estimated binocular function as "excellent" according to Biglan's system. Overcorrection of abduction did not occur. CONCLUSION: The result in our patient confirms the possibility of full functional recovery after surgical repair of a totally transected abducens nerve.

Abducens Nerve↗
PubMed1996

[Stereotactic irradiation for brain metastases using linear accelerator].

A stereotactic irradiation (STI) system using a linear accelerator was developed and its effectiveness for brain metastasis was investigated. The system consisted of a conventional linear accelerator, invasive fixation head frame (RADFRAME, Mizuho Ika Kogyo), and a tungsten collimator. The RADFRAME was developed to be used with any linear accelerators and with any dose planning systems. The accuracy of the irradiation was assured to be within +/-1.5mm. Fifty-one patients with metastatic brain tumors were treated using the system. The overall median survival time was 10 months. No difference in survival was observed between patients with a single lesion and patients with two or three lesions. Complete, partial, and minimal responses were obtained in 16 (39%), 18 (41%), and 7 (16%) lesions. These were comparable to the reported results of gamma knife treatment. A maximum dose of 25 Gy was suggested to be more effective than lower doses. Local control rate was higher in tumors with a diameter of less than 2.0cm (87.5%) than in larger tumors (60%). No difference in tumor response was observed among various histopathologic types. In a patient with a 25mm cerebellar metastasis from an adenocarcinoma of the lung, autopsy at 5 months after STI showed fibrinoid degeneration and hyaline deposition without residual tumor at the Gd-enhanced region on MRI. The efficacy of linac stereotactic irradiation was equal to that of gamma knife radiotherapy for metastatic brain tumors.

Adenocarcinoma↗
PubMed1991

[A case report of hemangioma of the petrous bone which caused facial spasm and facial palsy].

A rare case of hemangioma of the petrous bone is described. A 31-year-old woman suffered from right facial twitching and palsy. So she underwent a craniectomy intending microvascular decompression of the facial nerve, but no compressing vessels or tumors were found. Three years later, however, her facial fasciculation disappeared spontaneously, but facial weakness deteriorated and she began to feel vertigo. On admission, neurological examination revealed right facial palsy of the peripheral type, slight hearing disturbance, and canal palsy. Bone-window CT and T2-weighted MRI revealed a small tumor destroying the petrous bone near the geniculate portion of the facial nerve. Using the epidural subtemporal approach, the tumor was totally removed and the facial nerve remained intact. Histologically it was diagnosed as hemangioma. Hemangioma of the skull base bone is rare, and it is interesting that the tumor in this case caused abnormal facial contraction like hemifacial spasm.

Adult↗
PubMed1990

[Chemotherapy responsiveness of brain tumors in subrenal capsule assay].

The 6-day subrenal capsule assay for determining chemotherapeutic sensitivities of brain tumors was studied. Rat glioma 9L and ACNU resistant 9L-2 were transplanted under the renal capsule of normal immunocompetent WKA rats for laboratory investigation. Evaluation of implanted tumor growth till 12 days was performed. The effects of chemotherapeutic agents administered intravenously were evaluated by measuring the growth rate of implanted tumor specimens. The results obtained from SRC were compared with the results from colony forming assay. Both were correlated to each other. On the other hand, histological investigation revealed that implanted human tumor cells had been diminished and implanted tumor was replaced by immunoreactive cells from the host in many cases. These results threw doubt on a reliability of SRC. To avoid this immunoreaction, cyclophosphamide was injected as immunosuppressive agent subcutaneously 24 hours before implantation. In such cases, the growth rates of implanted tumors were increased and histologically the implanted tumor cells existed for 6 days after implantation. Twenty-three malignant brain tumors (malignant astrocytomas 16, metastatic tumors 5, malignant lymphoma 2) were obtained as surgical specimens. Evaluable assay rate of our study were 89%. 15 patients with malignant astrocytomas were studied about correlation between the sensitivities of ACNU and post-operative clinical courses. Overall clinical correlation of 15 cases of malignant astrocytomas was 47%. These results from subrenal capsule assay are not seemed to be beneficial for clinical use. Immunoreactive response when using immunocompetent rats must be solved in future.

Animals↗
PubMed1990

[The MR evaluation of normal children and disorders of neuronal migration and myelination].

We often experience the case that is difficult to differentiate normal from abnormal myelinating process by CT scan, because the diagnosis of myelinating maturation of the infant during developmental process is confusing. We can understand maturation of myelination adding to the advancement of diagnostic resolution by MR imager. So we obtain more informations about the abnormality of myelination and development of the brain by MR imaging than CT scan. This study demonstrates the ability of MR imaging to show progression of myelination in 10 infants and children. We also reveals the patients with disorders of neuronal migration or myelination during developing process. MR scanning could be obtained by sedation using such as triclofos or chloral hydrate for infant and younger children. It was necessary to use diazepam or pentazocine intravenously for elder children with mental retardation or restlessness. MR scans were performed with Siemens MAGNETOM 1.5 Tesla. T 1-weighted spin echo image (TR 600/TE 15) and T 2-weighted image (TR 3000/TE 90) were obtained for all cases. The ten normal infants and children (7 boys, 3 girls) were aged from 1 month to 4 years. Maturation of white matter generally proceeded from posterior limb of internal capsule to middle cerebellar peduncle, cerebellar white matter, corpus callosum, anterior limb of internal capsule, occipital white matter, centrum semiovale, finally frontal white matter. Myelination was matured during the first two years by T 2-weighted images. Changes caused by brain myelination were seen earlier on T 1-weighted images (7 months after birth) than on T 2-weighted images (one year and 9 months after birth).(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1990

[Phosphorus-31 MR spectroscopy of brain tumors].

Eleven normal volunteers and 17 subjects with brain tumors were studied by phosphorus-31 Magnetic Resonance (MR) spectroscopy. Measurements were performed by FROGS (Fast Rotating Gradient Spectroscopy) saturating nearly skin or muscle by Volume of Interest (VOI). This measurement took about 30 minutes for each case, including the imaging procedure, shimming and the measuring of spectroscopy. In phosphorus-31 MR spectroscopy, pH of the subjects with brain tumors showed a statistically significant elevation compared with that of the volunteers. In the subjects with benign tumors, only the elevation of pH was significant compared with that in volunteers. There was no other difference. This result suggests that benign tumors have an almost normal metabolic mechanism. Malignant brain tumors showed a decrease of PCr and an increase of Pi and PME. The increase of Pi indicates the increase of energy consumption. The increase of PME is connected with the acceleration of cell proliferation, there is a difference between malignant tumors and benign tumors. Phosphorus-31 spectroscopy has the potential to investigate the metabolism in vivo.

Astrocytoma↗
PubMed1988

[Five cases of primary intracranial germ cell tumor treated by combination chemotherapy with cisplatin].

Five cases of non-germinoma germ cell tumor which received combination chemotherapy with cisplatin were studied to elucidate the efficacy of chemotherapy. The patients' ages ranged from 7 to 24 years old. Three of the patients were male and two were female. Locations of the tumors were suprasellar in three cases, pineal in one case and basal ganglia in the other. Three of the 5 tumors were histologically verified as yolk sac tumors, embryonal carcinoma and HCG_producing germinoma. Two were histologically unverified HCG-producing tumors. Following the reception of PVB therapy (cisplatin, vincristine and bleomycin) by all the patients, three of the HCG-producing tumors showed complete remission and two of AFP producing tumors demonstrated partial remission, and progressive healing process, respectively. Renal dysfunction in two case, leukopenia in two cases and lung fibrosis in one cae were noted as side effects. Two cases were treated only with cisplatin because ling fibrosis due to administration of bleomycin was intractable and harmful. Also the time when irradiation. It seemed better to administer chemotherapeutic agents prior to or during irradiation on account of the fact that, after radiotherapy, there is reduced blood flow in the tumor region. Also, CDDP acts as a radiosensitizer. Therefore, individual administration of cisplatin during irradiation was recommended for the initial chemotherapy against the case of non-germinoma germ cell tumors, in which an intractable side effect might be expected.

Adolescent↗
PubMed1987

[A case of internal carotid artery aneurysm of the cavernous portion treated by trapping with the detachable balloon technic].

The authors report a case of internal carotid artery aneurysm of the cavernous portion, which was treated by trapping of the internal carotid artery using a detachable balloon technique. In April 1984, 56-year-old female was admitted with chief complaint of ptosis of the left eyelid lasting for the past two years. A neurological examination on admission revealed the left oculomotor nerve palsy. Contrast CT scan and left carotid angiogram showed an aneurysm at the cavernous portion of the internal carotid artery. On June 11th, three days before the trapping, superficial temporal artery-middle cerebral artery anastomosis was performed using short vein graft. On June 14th, the internal carotid artery was trapped at the distal and proximal portions of the aneurysmal neck using two Debrun's No. 16 balloons. Digital subtraction angiography taken two weeks after the trapping showed complete occlusion of the left internal carotid artery with no visualization of the aneurysm. Contrast CT scan taken three months after the trapping highly indicated complete thrombosis of the lumen of the aneurysm. Following the intravascular surgery, the left oculomotor paresis was gradually improved. The authors emphasized that the trapping of the internal carotid artery using a detachable balloon technique was the most safe and beneficial method for the treatment of the aneurysm located in the cavernous portion of the internal carotid artery.

Aneurysm↗
PubMed1986

[A case of multiple teratomas combined with embryonal carcinoma].

It is rare to find primary multiple teratomas among intracranial tumors. We report a case of multiple teratomas combined with embryonal carcinoma. A 22-year-old man was admitted to our hospital because of loss of appetite and emaciation. Neurological examination was negative except bilateral optic nerve atrophy and generalized hyperreflexia. The endocrinological study showed panhypopituitarism and partial DI. CT scan revealed irregularly enhanced abnormal masses involving suprasellar cistern and the septum pellucidum. The tumors were removed by the transcallosal approach, and the histopathological study showed mature teratoma which contained cartilage, epithelium of GI tract, ciliated epithelium, smooth muscle, fat tissue. Within the tumor of the septum pellucidum, nests of markedly pleomorphic epithelial tumor cells with necrosis, nuclear pleomorphism and mitosis were identified, embryonal carcinoma. At necropsy, no carcinomatous lesions were identified in other organs. Multiple teratomas from nonmetastatic, separate origins have been rate by reported in the literature. In our case, histologically, the mass in the suprasellar cistern was diagnosed as mature teratoma and the mass of the septum pellucidum was mature teratoma combined with embryonal carcinoma. It seemed likely that each of the tumors was developed from different origins.

Adult↗
PubMed1985

[External immobilization of cervical spine with a halo vest--experience with 31 cases].

Post-traumatic or post-operative immobilization of cervical spine often requires long term bed-rest. But, bed-rest indeed gave discomfort to patients, nonetheless, sometimes complete external fixation cannot be gained. Since 1982, we have applied Halo vest to the patients who required external immobilization of cervical spine. In this paper, we reported our experiences with 31 cases who were treated by Halo vest. Thirty-one cases comprised 19 cases of cervical spinal trauma, 5 cases of atlanto-axial dislocation, 1 case of foramen magnum meningioma, and 6 cases of ossification of posterior longitudinal ligament (OPLL). In traumatic cases, Halo vest was used as external fixation of injured spine in 8 cases, and as an adjunct to surgical fusion in other cases. In case of atlanto-axial dislocation, 3 cases underwent posterior fusion, and 2 cases underwent anterior fusion. Anterior fusion of C1-2 was also done in case of foramen magnum meningioma after total excision of tumor. Six cases of OPLL underwent anterior decompression and anterior fusion. Mean immobilization time by Halo vest was as follows: 58 days (28-113) in case of cervical spinal trauma, 85 days (56-144) in case of atlanto-axial dislocation who underwent posterior fusion, 92 days (89-93) in case of atlanto-axial dislocation and foramen magnum meningioma who underwent anterior fusion, 59 days (54-70) in case of OPLL. Early ambulation was achieved in many cases. Good external fixation and result was obtained 27 cases out of 31 cases. Re-dislocation of cervical spine occurred in 1 case of cervical spinal trauma while he was in Halo vest.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

[Nidus embolization of cerebral arteriovenous malformation fed mainly by a pericallosal artery prior to surgical excision. Case report].

Nidus embolization of large arteriovenous malformation (AVM) by silastic spheres is not rarely performed prior to surgical excision of AVM. This technique is highly indicated for the large AVM supplied by the middle and the posterior cerebral arteries since silastic spheres injected into either the internal carotid or the vertebral arteries usually enter the middle or the posterior cerebral arteries due to less sharp angle from the main arteries. The authors report a case whose AVM, fed mainly by the anterior cerebral artery, was successfully embolized with silastic spheres using balloon catheter technique. On December 1, 1983, a 27-year-old man was admitted to our department with chief complaint of headache and clonic convulsion of the left upper and lower limbs. Convulsion began in 1973 and severe headache suddenly appeared two months prior to admission. He was neurologically asymptomatic on admission. Right internal carotid angiogram taken on admission showed a presence of large arteriovenous malformation in the medial portion of the right fronto-parietal lobe and corpus callosum fed mainly by the right pericallosal artery. Nidus embolization with silastic spheres was planned to make surgical removal easier. To prevent stray of silastic spheres into the right middle cerebral artery, balloon, introduced into the M1, was inflated for a few minutes, during which time, injection of 40 silastic spheres of 1.5 and 2.0 mm in diameter was performed via the right internal carotid artery. The nidus was significantly reduced and total removal of the nidus was successfully done 28 days following the embolization.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

[Combined therapy of ventriculo-cisternal irrigation with external decompression in acute ruptured aneurysm].

Vasospasm after clipping of an acute ruptured aneurysm plays an important role in its prognosis. An effective therapy for vasospasm has not been established. We had attempted to remove the subarachnoid clot, which probably caused vasospasm, by ventriculo-cisternal irrigation and had not so good results (A: a group without decompression). Therefore, we have performed a therapy combined ventriculo-cisternal irrigation with external decompression (B: a group with decompression). We wish to report the efficacy of external decompression for an acute ruptured aneurysm. Evaluation of the outcome is due to Table 2. 55% of A group and 80% of B group have a better grade than "fair". Furthermore, a significant difference lies between A and B group associated with symptomatic vasospasm (brain ischemia caused by vasospasm). Namely, A group has all poor or dead cases but B group has 80% of the cases better than "fair". We concluded that relieving ICP by external decompression could suppress the aggravation of the post operative symptomatic vasospasm.

Acute Disease↗
PubMed1984

[Efficacy of nidus embolization of large arterio-venous malformation prior to surgical excision].

Although it is undoubted that surgical excision is the ideal treatment for arterio-venous malformation, its large nidus and deep localization make it difficult in some instances. To make surgical procedure easier, efficacy of nidus embolization or of obstruction of feeding arteries by detachable balloon technique is reported. A case presented here is such a case with large arterio-venous malformation which was successfully removed surgically following artificial nidus embolization with silastic spheres. On May 12th, 1983, a 27-year-old housewife was admitted to our department with chief complaints of episodes of alexia, apraxia, and aphasia lasting for a few minutes during 4 years prior to admission. Neurological examination on admission showed no abnormalities. Left internal carotid angiogram taken on admission showed a large arterio-venous malformation in the left parieto-temporo-occipital region fed by three branches of the left middle cerebral artery and two branches of the left posterior cerebral artery (Fig. 2a, 3a). To enable successful excision without neurological deficits, nidus embolization with silastic spheres was performed on June 2, 1983. Forty silastic spheres of 1.5 mm in diameter were injected via a catheter introduced in the left internal carotid artery and a second injection of 48 silastic spheres of 2.0 mm in diameter was performed after confirmation of no stray of silastic spheres in the arteries unrelated to the nidus. Embolization procedure was interrupted after the second injection, because of stray of silastic sphere into the posterior internal frontal artery of the left anterior cerebral artery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗