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K Koshu

Publications and source records attributed to K Koshu.

At least 19 recordsLinked to original sources
PubMed2000

Diffusion-weighted magnetic resonance imaging in the early evaluation of corticospinal tract injury to predict functional motor outcome in patients with deep intracerebral hemorrhage.

OBJECT: Diffusion-weighted (DW) magnetic resonance imaging was used to visualize corticospinal tract injury in patients with deep intracerebral hemorrhage (ICH), and the results were used to predict motor impairment of the extremities. METHODS: Twenty-eight patients with deep ICH (17 men and 11 women, mean age 58+/-14 years) were examined. The volume of the ICH was assessed on initial computerized tomography scans. Twelve patients had ICH volumes of 40 ml or more and were treated surgically, and 16 patients who had an ICH volume of less than 40 ml were treated medically. Initial corticospinal tract injury was classified into four grades according to the anatomical relationship between the corticospinal tract and the ICH on DW images. Motor impairment of both the upper and lower extremities was assessed at admission and 1 month poststroke by using the National Institutes of Health Stroke Scale. The extent of correlation was determined between motor impairment and corticospinal tract injury. Initial corticospinal tract injury was not correlated with the impairment of extremities at admission but was closely correlated with motor impairment of the upper (r = 0.843, p < 0.001) and lower (r = 0.868, p < 0.001) extremities at 1 month poststroke. Impairment of the upper extremities correlated better with anterior than with posterior corticospinal tract injury (r = 0.911 compared with r = 0.600), and impairment of the lower extremities correlated better with posterior than with anterior injury (r = 0.890 compared with r = 0.787). CONCLUSIONS: Early evaluation of corticospinal tract injury based on DW imaging can provide predictive value for motor functional outcome in patients with deep ICH.

Adult↗
PubMed2000

Hypofixation and hyperfixation of 99mTc-hexamethyl propyleneamine oxime in subacute cerebral infarction.

UNLABELLED: The relationship between hypofixation and hyperfixation of 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) remains unclear. The purpose of this study was to compare 99mTc-HMPAO SPECT with regional cerebral blood flow (CBF) imaging using 133Xe inhalation in patients with subacute cerebral infarction and to investigate the behavior of 99mTc-HMPAO in the infarct area using dynamic SPECT. METHODS: 133Xe and consecutive 99mTC-HMPAO SPECT studies, the latter of which consisted of dynamic and static scanning, were performed on 51 patients (22 women, 29 men; age range, 40-83 y; mean age, 61 y) with cortical infarction in the middle cerebral artery territory 13-15 d after stroke onset. One region of interest (ROI) was drawn in the infarct area. The control ROI was mirrored to the contralateral side, and the same set of ROIs was applied to all SPECT studies. Fractional fixation of 99mTc-HMPAO in the infarct area was evaluated relatively as the ratio of the infarct-to-control region in 99mTc-HMPAO static tomograms/the ratio of the infarct-to-control region in CBF images using 133Xe inhalation and was classified as hyperfixation when this value was >1.1 and hypofixation when this value was <0.9. To investigate the behavior of 99mTc-HMPAO in the infarct area, the second (36-72 s after tracer injection) and eighth (252-288 s after tracer injection) of 8 dynamic scans were selected, and the washout rate was calculated using the formula: 1 - (mean count in the eighth scan/mean count in the second scan). RESULTS: The infarct area showed hyperfixation of 99mTc-HMPAO when CBF in the area was 35 mL/100 g/min or less and showed hypofixation when CBF was >45 mL/U100 g/min. The washout rate was usually negative when CBF imaging using 133Xe inhalation was <20 mL/100 g/min but was positive when it was >45 mUL/100 g/min. The washout rate was negative when the infarct area showed hyperfixation of 99mTc-HMPAO but was positive when it showed hypofixation. CONCLUSION: 99mTc-HMPAO SPECT underestimates CBF in high-flow regions and overestimates CBF in low-flow regions of subacute cerebral infarction. 99mTc-HMPAO hypofixation and hyperfixation are associated with backdiffusion from the brain to blood and gradual accumulation of hydrophilic metabolites, respectively. Dynamic images should be useful for discriminating between 99mTc-HMPAO hypofixation and hyperfixation.

Adult↗
PubMed2000

Intraoperative mild hypothermia ameliorates postoperative cerebral blood flow impairment in patients with aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Intraoperative mild hypothermia has been used during cerebral aneurysm surgery to reduce ischemic injury induced by temporary vessel occlusion and brain retraction. However, the clinical effects on cerebral hemodynamics are unclear. This study investigated the effects of intraoperative mild hypothermia on cerebral blood flow (CBF) after surgery to treat aneurysmal subarachnoid hemorrhage. METHODS: Twenty-four patients with ruptured internal carotid or middle cerebral artery aneurysms, of preoperative Hunt and Hess Grade II or III, underwent aneurysm clipping within 72 hours after the onset of subarachnoid hemorrhage. During surgery, patients were randomly assigned to either intraoperative mild hypothermia (33.5 degrees C, n = 12) or normothermia (37 degrees C, n = 12). Brain single photon emission computed tomography with 99mTc-hexamethylpropylenamine oxime or 99mTc-L,L-ethylcysteinate dimer was performed on Days 4, 7, and 14 after subarachnoid hemorrhage. Regional CBF was determined in the basal ganglia and cingulate, frontal, and frontoparietal cortices, using a semiquantitative method. RESULTS: CBF in the frontal cortex ipsilateral to the aneurysm was significantly higher in the hypothermia group than in the normothermia group on Day 4 (P<0.01) but not Day 7 or 14. There was a similar trend in the ipsilateral frontoparietal cortex, but it was not significant. There were no differences in regional CBF in the ipsilateral cingulate cortex or basal ganglia or in any contralateral region during the study period. CONCLUSION: Intraoperative mild hypothermia may reduce the severity of ischemia induced by intraoperative temporary vessel occlusion and brain retraction, thus ameliorating postoperative CBF impairment.

Adult↗
PubMed2000

[Acute epidural hematoma caused by contrecoup injury].

We report a rare case of the acute epidural hematoma caused by contrecoup injury. A 59-year-old woman came to our hospital on foot because of her head injury. She slipped on a stone and hit her occiput against the concrete floor without loss of consciousness. On admission she was alert and complained of dizziness and nausea without neurological deficits. She had a subcutaneous hematoma in the occiput. There was no Battle's sign nor cerebrospinal fluid leakage. Skull film revealed a linear fracture of the occipital bone. Computed Tomography(CT) of the brain showed the acute epidural hematoma at the left frontal region. She was treated conservatively and discharged 19 days after injury without neurological deficits. The mechanism of this lesion is speculated as follows: the deformation of the skull and the negative pressure produced in the frontal region with the occipital injury stripped the dura mater from the calvarium, which lead to the rupture and hemorrhage of the small interposed vessels resulting in the epidural hematoma.

Accidental Falls↗
PubMed1999

Quantitative analysis of cerebrospinal fluid flow in patients with cervical spondylosis using cine phase-contrast magnetic resonance imaging.

OBJECTIVE: To investigate changes in the cerebrospinal fluid flow in patients with cervical spondylosis using cine phase-contrast magnetic resonance (MR) imaging. METHODS: The participants included 44 healthy volunteers, 11 asymptomatic patients with evidence of degenerative changes of the cervical spine revealed by MR imaging but no neurological symptoms referable to those abnormalities, and 23 symptomatic patients with myelopathy who underwent surgery. Cervical spondylotic myelopathy was evaluated using the Japanese Orthopedic Association scores, and the percentage reduction of the transverse cord area at the level of maximum cord compression was measured on T1-weighted magnetic resonance images. A cine phase-contrast MR pulse sequence with peripheral gating was used to measure the cerebrospinal fluid flow direction and velocity in the ventral subarachnoid spaces at the C1 and T1 levels. RESULTS: The velocity waveforms produced by plotting flow velocity at 16 intervals during one cardiac cycle significantly differed among the healthy volunteers, asymptomatic patients, and preoperative symptomatic patients. However, velocity waveforms did not differ between the healthy volunteers and the postoperative patients at the C1 level. Decreases of flow velocity were significantly correlated with the severity of myelopathy and the percentage reduction of cord area. Patients with severe myelopathy (Japanese Orthopedic Association score of 0-9 points) or greater than 30% reduction of cord area showed significantly decreased flow velocity compared with those with mild myelopathy (Japanese Orthopedic Association score of 10-17 points) or less than 30% reduction of cord area. Changes in flow velocity were not correlated with multiplicity of the lesion or the level of maximum cord compression. Postoperative improvement of flow velocity was not correlated with neurological recovery. CONCLUSION: Cine phase-contrast MR imaging allows quantitative and noninvasive assessment of changes in cerebrospinal fluid flow in patients with cervical spondylosis.

Adult↗
PubMed1999

Transient hyperemia immediately after rapid decompression of chronic subdural hematoma.

OBJECTIVE: Intracerebral hemorrhage occurring after removal of a chronic subdural hematoma (CSH) is a rare but usually devastating postoperative complication. In patients with CSH, we determined cerebral blood flow immediately after surgical decompression to clarify the pathogenic mechanism of this complication. METHODS: In 22 patients with unilateral CSH, a catheter was inserted into the hematoma cavity through a single burr hole without leakage of the contents. Cerebral blood flow was measured using single-photon emission computed tomography 1 day before surgery, immediately after rapid decompression by opening the catheter, and 3 days after surgery. RESULTS: Single-photon emission computed tomography imaging immediately after decompression demonstrated areas of hyperemia in nine patients (41%). In all nine patients, hyperemia was observed in the cortex beneath the CSH, and it disappeared on the 3rd postoperative day. The patients with hyperemia were significantly older than those without hyperemia. Other variables, including preoperative cerebral blood flow, intrahematoma pressure before decompression, and mean arterial blood pressure during decompression had no significant effect on the occurrence of hyperemia. CONCLUSION: In elderly patients, rapid decompression of CSH frequently results in transient hyperemia in the cerebral cortex beneath the hematoma.

Aged↗
PubMed1998

Solitary plasmacytoma in the thoracic spine. Two case reports.

Plasmacytoma of the spine is rather common, but solitary occurrence is not. We report two cases of solitary plasmacytomas in the thoracic spine. A 72 year old male and a 77 year old male presented with progressive paraparesis. In both cases, magnetic resonance images revealed tumors in the thoracic spine which predominantly occupied the posterior elements of the spine with compression of the spinal cord. Abnormal proteinuria and proteinemia were not detected. The tumors were removed and patients' symptoms improved, the tumors were diagnosed by histopathology to be plasmacytomas. Further neuroradiological studies suggested them to be single lesions, so that the final diagnosis was solitary plasmacytomas. Solitary plasmacytoma should be considered for diagnosis of single spinal lesion even without abnormal proteinemia or proteinuria.

Aged↗
PubMed1998

Dural arteriovenous shunts at the craniocervical junction.

OBJECT: A retrospective analysis was conducted of 10 patients (three women and seven men) who were treated for spinal dural arteriovenous shunts (AVSs) located at the craniocervical junction. This analysis was performed to evaluate the characteristics of this unusual location in contrast with those of the more common thoracic and lumbar AVSs. METHODS: Seven patients presented with subarachnoid hemorrhage (SAH) and one with slowly progressive quadriparesis and dyspnea due to myelopathy. The other two cases were detected incidentally and included a transverse-sigmoid dural AVS and a cerebellar arteriovenous malformation. Angiographic studies revealed that the spinal dural AVSs at the C-1 and/or C-2 levels were fed by the dural branches of the radicular arteries that coursed from the vertebral artery and drained into the medullary veins. Venous drainage was caudally directed in the patient with myelopathy. In contrast, the shunt flow drained mainly into the intracranial venous system in patients with SAH. Furthermore, in four of these patients a varix was found on the draining vein. In all patients, the draining vein was interrupted surgically at the point at which this vessel entered the intradural space, using intraoperative digital subtraction angiography to monitor flow. The postoperative course was uneventful in all patients and no recurrence was confirmed on follow-up angiographic studies obtained in seven patients at 6 months after discharge. CONCLUSIONS: If computerized tomography scanning shows SAH predominantly in the posterior fossa and no abnormalities are found on intracranial four-vessel angiographic study, proximal vertebral angiography should be performed to detect dural AVS at the craniocervical junction. The results of surgical intervention for this disease are quite satisfactory.

Adult↗
PubMed1998

[Differential diagnosis of hyponatremia following subarachnoid hemorrhage].

Hyponatremia is a common complication after subarachnoid hemorrhage (SAH). Although the mechanism of hyponatremia is still controversial, cerebral salt-wasting syndrome (CSNS) is currently regarded as being more responsible than the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). The aim of our study was to assess the plasma volume status of a patient with hyponatremia following subarachnoid hemorrhage. In doing this it may be possible to indirectly differentiate its pathogenesis. Fifty patients with SAH were studied. Twenty patients demonstrated hyponatremia (serum sodium < 135 mEq/L) during day 7 to 13 after subarachnoid hemorrhage. Patients with hyponatremia were categorized on the basis of their daily body weight, and central venous pressure. Group A consisted of patients with hypovolemia (16 patients), with the onset time of hyponatremia being day 7 to 9. Group B included those with hypervolemia (4 patients); hyponatremia was observed during day 10 to 11 and was corrected in all patients within 72 hours after induction of fluid restriction. Our findings suggest that hyponatremia following subarachnoid hemorrhage usually occurs due to CSWS, although SIADH remains as a minor pathogenesis. We conclude that the combination of daily body weight and CVP measurements is a simple and practical method to distinguish promptly SIADH from CSWS.

Adult↗
PubMed1997

Biomechanical evaluation of hydroxyapatite intervertebral graft and anterior cervical plating in a porcine cadaveric model.

The biomechanical properties of a porous hydroxyapatite (HA) intervertebral graft with or without anterior cervical plating were evaluated in cadaveric porcine cervical spine model using C3-4 discectomy and dissection of the posterior longitudinal ligament to cause instability. The experimental groups were intact (n = 11), instability (n = 11), autogenous bone implant (n = 6), HA graft implant (n = 5), autogenous bone with plating (n = 6), and HA graft with plating (n = 5). Porous HA with 40% porosity and scapular bone were used as grafts. The displacement rates of the cervical spine by compressive forces in the flexural, extensional, and lateral bending directions were evaluated using video-recording followed by computer-assisted analysis. The stiffness to compressive load was calculated from the load-displacement rate curve. The linear and non-linear coefficients of the Fung's equation were obtained based on the plot of Young's modulus against load. There were no statistical differences in the stiffness between the HA and autogenous bone graft in all directions. The two plating groups showed significantly increased stiffness in all directions. The non-linear coefficient value in Fung's equation was far larger in both HA and HA graft with plating groups than in the other groups in flexural compression. Porous HA graft has a compressive strength similar to autogenous graft in vitro, and anterior plating provides additional stiffness to the cervical spine. The larger non-linear coefficient value of the HA groups may represent the characteristic biomechanical brittleness of HA graft, but this is manifest only in flexural compression.

Animals↗
PubMed1995

How to treat incidental cerebral aneurysms: a review of 139 consecutive cases.

BACKGROUND: Together with current advances in neuroimaging techniques, the chance of incidental discovery of unruptured cerebral aneurysms has increased and the selection of their appropriate management remains controversial. To provide current data about management results of patients with incidental cerebral aneurysms, we have made a retrospective review of 139 consecutive patients treated either by surgical or conservative means. METHODS: The surgical indication for each patient was decided, carefully considering several factors respectively, including the surgical difficulty, aneurysm size, patient's age, and medical condition. RESULTS: Forty-nine patients were managed conservatively. Eight (16%) of those conservatively managed patients had intracranial hemorrhage due to aneurysm rupture during the follow-up period (mean, 4.3 years). Seven of these eight patients died from a fatal subarachnoid hemorrhage (SAH). The follow-up data showed that the mean size of aneurysms with late hemorrhage was significantly larger than that of aneurysms without subsequent rupture. It was also confirmed that none of the 26 tiny aneurysms smaller than 4 mm in diameter had ruptured. Ninety patients harboring 119 incidental aneurysms less than 25 mm in diameter underwent surgery. There was no surgical mortality or morbidity in this series. CONCLUSIONS: These excellent surgical results were presumably achieved due to the strict patient selection. In respect to the size of aneurysms, it seems to be justified to recommend surgery for patients with aneurysms larger than 5 mm in diameter.

Adult↗
PubMed1995

Magnetic resonance imaging of titanium anterior cervical spine plating systems.

Magnetic resonance imaging (MRI) of titanium anterior cervical plating systems and their effect on postoperative images were evaluated ex vivo and in vivo. The Synthes and Caspar plating systems were examined by 0.5- or 1.5-T MRI scanners. A phantom study of these implants showed that in spin-echo modes, the plates and screws were seen as areas of signal loss accompanying a marginal hyperintense band, which was more obvious in higher tesla magnetic fields. Distortion of the magnetic field was more prominent in T2-weighted images. In gradient echo mode, the plate and screws were seen as areas of signal loss larger than the size of the metal because of the magnetic susceptibility effect. Postoperative MRI produced images of the implants similar to those observed ex vivo. The Synthes plating system did not interfere with the evaluation of the spinal cord, and the Caspar screw (which penetrated the posterior cortex of the vertebral body) caused a small artifact to be present at the anterior aspect of the spinal cord. In addition to being able to provide fixation of the cervical spine, titanium anterior cervical plates allow superior MRI of the postoperative spine.

Artifacts↗
PubMed1995

Spinous process-splitting laminoplasty with an extended foraminotomy for cervical myelopathy.

We present the surgical results of a laminoplasty with an extended foraminotomy for cervical myelopathy. We chose spinous process-splitting laminoplasty, because it gave us the opportunity to perform bilateral foraminotomies through the same exposure. An extended foraminotomy means that root decompression is performed as far laterally as possible, using the surgical microscope. We performed this method in 18 patients and experienced favorable clinical results. Neuroradiological evaluations revealed good decompression of the spinal cord postoperatively. Although the operation time needed was longer compared with the original method, the average blood loss was 430 ml and blood transfusion was necessary in five patients. This method can be considered when cervical myelopathy is treated by a posterior approach.

Cervical Vertebrae↗
PubMed1995

[Surgical decompression for massive cerebellar infarction].

The authors report 10 patients with progressive neurological deterioration due to massive cerebellar infarctions. Computerized tomography scans confirmed obstructive hydrocephalus and brain stem compression. All 10 patients (seven men, three women; mean age, 59 years) were treated by external ventricular drainage and decompressive suboccipital craniectomy. After discharge from the hospital, they were followed up (23-101 months) and their functional independence was evaluated by the Barthel Index. The condition of three patients with brain-stem infarction had deteriorated despite decompressive surgery. Two of these died during the acute stage and one because severely disabled. The remaining seven patients showed neurological improvement during the postoperative period. Four patients with preoperative Japan Coma Scale of 100 returned to their previous jobs within the follow-up period and three patients with preoperative Japan Coma Scale of 200 required some assistance in daily activities. It is suggested that decompressive surgery may be beneficial for massive cerebellar infarction. The postoperative prognosis depends mainly on the presence or absence of coexisting brain-stem infarction. It is possible that, without brain-stem infarction, patients who remained in a "dependent" state may have recovered better if they had been operated on earlier.

Aged↗
PubMed1994

Anterior cervical fixation with the titanium locking screw-plate: a preliminary report.

Anterior fixation of cervical spine with screw-plates is gaining in popularity in the management of anterior cervical spine instability. We report on our initial experience with anterior cervical fixation using the titanium locking screw-plate (TLSP). Twelve cases, including cervical trauma, cervical spondylosis, and ossification of the posterior longitudinal ligament (OPLL), underwent multilevel corpectomies or spondylectomies with iliac bone or hydroxylapatite grafting combined with the TLSP system. All 12 patients fused or stabilized with improvement of their neurologic symptoms at a mean follow-up period of 13 months. There were no complications relating to this plating system. Three illustrative cases are presented. Different from previous anterior cervical planting systems such as the Caspar plate, the TLSP system does not gain purchase on the posterior vertebral cortex. It thus reduces possible spinal cord injury during screw placement. The TLSP with interbody fusion may provide reliable stabilization of the cervical spine in a safe and effective manner.

Adult↗
PubMed1994

Monitoring of brain tissue haemoglobin concentration and oxygen saturation using a three wavelength spectrophotometric method.

The authors report a new method of monitoring tissue oxygen saturation and haemoglobin concentration simultaneously and continuously using a three-wavelength spectrophotometry. Light emitting diodes were used as light source which made the recording probe small and flexible enough to be placed on the brain surface tightly. Stable and reliable recording of the tissue oxygen saturation and haemoglobin concentration was ascertained in the experimental studies using middle cerebral artery occlusion model of rabbit. In the clinical studies, monitoring during bypass surgery detected rapid changes of local oxygen metabolism and haemoglobin concentration in ischaemic brain. Simultaneous and continuous monitoring of tissue oxygen saturation and haemoglobin concentration enables more practical analysis of brain circulation and oxygen metabolism in experimental and clinical situations.

Adult↗
PubMed1994

Metastatic meningioma to the second cervical vertebral body: a case report.

A rare case of C2 vertebral body metastasis from a parasagittal meningioma is reported. The metastatic lesion was found 13 years after resection of the primary lesion. The primary and the metastatic lesions had a similar and benign histological appearance. Remote metastasis of a meningioma can occur even with a benign histological finding after a variable disease-free period.

Adult↗