Interstitial spinal-cord oedema in syringomyelia associated with Chiari type 1 malformations.

OBJECT: The pathophysiology of syringomyelia in Chiari type 1 malformations has not been clarified. Oedema-like spinal-cord swelling was recently reported in several pathological conditions, including Chiari type 1 malformations as a pre-syrinx state. However, the role of the pre-syrinx state in the development of syringomyelia is unknown. The purpose of this study is to investigate the parenchymal changes of the spinal cord in syringomyelia associated with Chiari type 1 malformations. METHODS: Pre- and postoperative MRI findings in 14 patients who underwent foramen magnum decompression in our institute were reviewed. The analysis was focused on differences in visualisation of the syrinx between T1- and T2-weighted images and abnormal parenchymal signal changes. There were 6 men and 8 women, aged from 6 to 79 years. No patients showed hydrocephalus. RESULTS: Twelve patients had large and expansive syrinx, whereas 2 patients showed small syrinx confined to the centre of the spinal cord. T2-weighted images displayed significantly larger intramedullary abnormal signal areas. Nine patients showed parenchymal hyperintensity areas around the enlarged central canal or base of the posterior white columns adjacent to the syringomyelic cavity. Such parenchymal hyperintensity areas markedly diminished with reduction of the syrinx after surgery and were considered to be interstitial oedema. CONCLUSIONS: From this study, the interstitial oedema of the spinal cord commonly accompanies syringomyelia with Chiari type 1 malformations. Accumulation of the extracellular fluid due to disturbed absorption mechanisms may play an important role in the pathophysiology of syringomyelia associated with Chiari type 1 malformations.

Evaluation of carotid plaque composition by computed tomographic angiography and black blood magnetic resonance images.

The purpose of this study was to evaluate quantitatively the composition of carotid plaque by computed tomographic (CT) angiography and qualitatively by black blood magnetic resonance images (MRI). Thirty-eight patients with high-grade carotid artery stenosis were included in this study. Ultrasonography, CT angiography and black blood MRI of the cervical carotid artery were performed, and the CT number was measured in Hounsfield units (HU). The average CT number of the 15 unstable plaques (39.5%) was 27.7+/-7.5 HU and that of the 23 stable plaques (60.5%) was 60.4+/-20.8 HU (p=0.0001). In the 23 patients with stable plaque, 21 demonstrated isointensity in T (1)- and T (2)-weighted images in the black blood MRI (p=0.0001). By using CT angiography and MRI, precise images of the pathology of the carotid arterial wall can be obtained. It is possible to evaluate the components of carotid artery plaque with high reliability by quantification of the CT number in CT angiography and performing black blood MRI as well as carotid ultrasonography.

Evaluation of carotid plaque composition by computed tomography angiography and black blood magnetic resonance image.

SUMMARY: The purpose of this study was to evaluate the composition of a carotid plaque quantitatively by computed tomography (CT) angiography and qualitatively by black blood magnetic resonance imaging (MRI). Thirty-eight patients with high-grade carotid artery stenosis were included in this study. Ultrasonography, CT angiography and black blood MRI of the cervical carotid artery were performed, and the CT number was measured in Hounsfield units (HU). The average CT number of the 15 unstable plaques (39.5%) was 27.7 +/- 7.5 HU and that of the 23 stable plaques (60.5%) was 60.4 +/- 20.8 HU (p < 0.0001). In the 23 patients with stable plaque, 21 demonstrated isointensity in T1 and T2 in the black blood MRI (p < 0.0001). By using CT angiography and MRI, precise images of the pathology of the carotid arterial wall can be obtained. It is possible to evaluate the components of a carotid artery plaque with high reliability by quantification of the CT number in CT angiography and performing black blood MRI as well as in carotid ultrasonography.

The 5-hydroxytryptamine2A receptor antagonist sarpogrelate hydrochloride inhibits acute platelet aggregation in injured endothelium.

In this study, the effect of sarpogrelate hydrochloride, a 5-hydroxytryptamine2A receptor antagonist, on platelet aggregation at the site of injured carotid artery endothelium was examined. The rat common carotid artery was clamped for 30 min to induce endothelial injury. Sarpogrelate hydrochloride was administered before and after the injury, and the effects were compared with those in rats receiving sham operation only and those receiving clipping injury but no sarpogrelate hydrochloride. The animals were killed 24 h after the procedure. The common carotid artery was examined by scanning electron microscopy and stained immunochemically for factor VIII. Sarpogrelate hydrochloride treatment was associated with reduced aggregation of platelets on electron microscopy and lower expression of factor VIII at the injured intima. Sarpogrelate hydrochloride has an inhibitory effect on platelet aggregation at the intima in the acute stage after injury, suggesting that this drug may be used to prevent early ischaemic complications after surgical or endovascular arterial intervention.

Reversible brain dysfunction in MELAS: MEG, and (1)H MRS analysis.

This case report describes a follow up investigation of a patient with impaired word discrimination due to mitochondrial encephalopathy with lactic acidosis and stroke-like syndrome (MELAS) using proton magnetic resonance spectroscopy ((1)H MRS) and auditory evoked magnetic fields (AEFs). The initial (1)H MRS showed no N-acetyl aspartate (NAA) and marked accumulation of lactate (Lac) in the stroke-like lesion of MELAS, which was silent in neural activity according to AEFs. The follow up investigations, however, demonstrated that NAA reappeared, that the formerly increased Lac signal was significantly reduced, and that the magnitude of AEFs of the lesion was markedly increased. Metabolic and functional changes in (1)H MRS and AEFs reflected the neurological recovery very well. The stroke-like lesion was shown, using AEFs and (1)H MRS, to be able to function properly, although brain tissue of the lesion initially had severe damage due to mitochondrial dysfunction.

Acute cervical cord injury without fracture or dislocation of the spinal column.

OBJECT: It is known that the spinal cord can sustain traumatic injury without associated injury of the spinal column in some conditions, such as a flexible spinal column or preexisting narrowed spinal canal. The purpose of this study was to characterize the clinical features and to understand the mechanisms in cases of acute cervical cord injury in which fracture or dislocation of the cervical spine has not occurred. METHODS: Eighty-nine patients who sustained an acute cervical cord injury were treated in our hospitals between 1990 and 1998. In 42 patients (47%) no bone injuries of the cervical spine were demonstrated, and this group was retrospectively analyzed. There were 35 men and seven women, aged 19 to 81 years (mean 58.9 years). The initial neurological examination indicated complete injury in five patients, whereas incomplete injury was demonstrated in 37. In the majority of the patients (90%) the authors found degenerative changes of the cervical spine such as spondylosis (22 cases) or ossification of the posterior longitudinal ligament (16 cases). The mean sagittal diameter of the cervical spinal canal, as measured on computerized tomography scans, was significantly narrower than that obtained in the control patients. Magnetic resonance (MR) imaging revealed spinal cord compression in 93% and paravertebral soft-tissue injuries in 58% of the patients. CONCLUSIONS: Degenerative changes of the cervical spine and developmental narrowing of the spinal canal are important preexisting factors. In the acute stage MR imaging is useful to understand the level and mechanisms of spinal cord injury. The fact that a significant number of the patients were found to have spinal cord compression despite the absence of bone injuries of the spinal column indicates that future investigations into surgical treatment of this type of injury are necessary.

Factors in neurological deterioration and role of surgical treatment in lumbosacral spinal lipoma.

The purpose of this study was to determine factors that might be involved in neurological deterioration and the role of surgical treatment in patients with lumbosacral spinal lipoma. Pre- and postoperative courses of 34 patients were retrospectively analyzed. The age at surgery ranged from 1 month to 47 years. The records of preoperative neurological status indicated that older patients had more severe deficits, while all 8 asymptomatic patients were under 5 years of age. Motor deficits were noted in 9 patients, in 7 of whom the lipoma extended cranially beyond the L5 level. Transitional-type lipomas were accompanied by more severe deficits (asymptomatic 1, symptomatic 17) than other types (asymptomatic 7, symptomatic 9). Postoperative follow-up periods ranged from 5 months to 13 years. During these periods, 7 of the 8 asymptomatic patients remained neurologically intact. Nine of the 26 symptomatic patients improved. Age, extension of the lipoma in the spinal canal and type of lipoma will influence the preoperative neurological status of the patients. Early untethering surgery is recommended in patients with large lipomas extending beyond the L5 level.

Reevaluation of syringosubarachnoid shunt for syringomyelia with Chiari malformation.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of syringosubarachnoid (S-S) shunting for syringomyelia with Chiari malformation. The authors describe the technical methods of performing the S-S shunt and the clinical results, including shunt malfunction. METHODS: Forty-nine patients underwent S-S shunting. These patients were divided into three groups according to differences in the surgical technique used. Group I patients underwent laminectomy plus midline myelotomy and had a shunt tube placed in the dorsal subarachnoid space. Group II patients underwent laminectomy plus dorsal root entry zone myelotomy and had a shunt tube placed in the dorsolateral subarachnoid space. Group III patients underwent hemilaminectomy plus dorsal root entry zone myelotomy and had a shunt tube placed in the ventrolateral subarachnoid space. RESULTS: Clinical results were generally satisfactory, especially in terms of pain relief, in all three groups. However, 10 patients among Groups I and II required follow-up surgery because of shunt problems; no second surgery was necessary for any patient in Group III. CONCLUSION: The S-S shunt was very effective in deflating the syrinx, and the clinical results were satisfactory. Therefore, even though foramen magnum decompression is a very effective treatment, S-S shunting should be reevaluated and not rejected; it should be considered as one of the major surgical options. To prevent the possibility of cord injury by myelotomy or shunt malfunction, the dorsal root entry zone should be selected as the myelotomy site, and the shunt tube should be inserted into the ventral subarachnoid space at the cervical level.

MRI at 1.5 T of intramedullary ependymoma and classification of pattern of contrast enhancement.

We retrospectively reviewed the MRI findings in 28 patients with an intramedullary spinal cord ependymoma who underwent surgical treatment. There were 26 tumours in the cervical and two in the thoracic spine. T1- and T2-weighted and contrast-enhanced images at 1.5 T were obtained in all cases. T1-weighted imaging showed solid tumour as isointense in 13 patients, high-signal in ten and low signal in five. In contrast, T2-weighted imaging showed all tumours as high signal. Contrast enhancement was heterogeneous 13 patients, homogeneous 10, heterogeneous with cyst wall enhancement in three, and a nodule on a cyst wall was seen in two. Cases with these latter patterns require careful differential diagnosis from astrocytoma or haemangioblastoma.

Vascular anatomy of the spinal cord and classification of spinal arteriovenous malformations.

SUMMARY: The arterial and venous anatomy of the spinal cord was described in terms of extrinsic and intrinsic contribution to the cord substance. Based upon anatomical location of an arteriovenous shunt, spinal arteriovenous malformations (AVMs) were classified into intramedullary AVM, perimedullary arteriovenous fistula (AVF) and dural AVF. This simple classification seems practical from the standpoint of endovascular and surgical treatments since it reflects anatomical differences in the shunt location, which is the target in either approach.

Autoradiographic [3H]nimodipine distribution after experimental spinal cord injury in rats.

Because of its potential for augmentation of blood flow and protection of neurons after neurological insult, nimodipine has been investigated as a treatment of spinal cord injury (SCI). The results have been inconsistent, possibly because of poor delivery of nimodipine to the injured spinal cord. The following study was designed to determine the delivery of nimodipine to the injured spinal cord. It was also hoped that information about the temporal and spatial pattern of binding of nimodipine after SCI might further elucidate the relationship between calcium channel activation and injury. Fourteen female Wistar rats were divided into three groups: control (n = 3), 30 min post-SCI (n = 6); and 4 h post-SCI (n = 5). The injury was produced by acute clip compression for 1 min at T1. [3H]Nimodipine was administered 5 min after laminectomy in the control group, and at the above-specified times after injury in the SCI groups. The drug was then allowed to equilibrate for 30 min before the animals were killed. The spatial patterns and concentrations of [3H]nimodipine in various segments of the spinal cord were autoradiographically determined. The highest concentrations of [3H]nimodipine were at the injury site after SCI. Also, the mean [3H]nimodipine concentrations in all sites in each animal were higher in the injury groups than in the control group (p < 0.05). This study indicates that delivery of this agent to the injured cord is possible, and provides evidence of widespread Ca2+ channel activation in the first 4 h after injury.

Syringo-subarachnoid shunt for syringomyelia using partial hemilaminectomy.

Syringo-subarachnoid shunt (S-S shunt) is one of the established surgical procedures for syringomyelia. However, this procedure requires a laminectomy which may lead to spinal column complications. We present a modified form of S-S shunt using a partial hemilaminectomy; a S-S shunt is placed via the dorsal root entry zone into the anterior subarachnoid space which is considered to be an ideal site for the drainage of the syrinx fluid. This technique will decrease the incidence of neuronal and spinal complications after surgery and avoid subarachnoid adhesions around the shunt tube. Between 1992 and 1997, a total of 24 patients with syringomyelia have been treated with this surgical procedure without any complications. Collapse of the syrinx was achieved in all cases. The authors believe that the procedure is an effective surgical treatment for syringomyelia and can be applied safely to adolescent and child cases.

[Clinical reference values for laboratory hematology tests calculated using the iterative truncation method with correction: Part 2, Reference values for white blood cell (WBC) count, WBC differential including segmented neutrophil, band neutrophil, lymphocyte, monocyte, eosinophil, basophil, platelet count and mean platelet volume].

Age and sex dependent differences in the clinical reference values for white blood cell(WBC) count, WBC differential including segmented neutrophils(SEG), band neutrophils(BAND), lymphocytes (LYMPH), monocytes(MONO), eosinophils(EOSINO), basophils(BASO), platelet count(PLT) and mean platelet volume(MPV) were calculated by the iterative truncation method with correction(Usui's method) using the result from tests on 6,300 patient specimens obtained at Kyoto University Hospital. WBC counts exhibited log-normal distribution in all age either in male and female. PLT counts and MPV showed normal or log-normal distribution. WBC differential (SEG, BAND, LYMPH, MONO, EOSINO, BASO) usually showed log-normal distribution. As to the reference value for WBC, high limit values gradually decreased in the age range of 5-14 year old in males and females. After 15 year old, it gradually increased and reached adult's level. Low limit values for WBC gradually decreased with age both in males and females. The reference value for SEG showed similar change to WBC. The reference value for LYMPH gradually decreased age both in males and females. The reference values for BAND, MONO, EOSINO, BASO were generated by the percentile method instead of the iterative truncation method because of the strong deviation in the distribution pattern. BAND, MONO and BASO values were very stable for all ages in males and females. High limit values for EOSINO in the age range of 5-10 year old in males and females remained constant, and gradually decreased in 10-20 year old, and were stable at ages above 20 year old. PLT counts gradually decreased with age, and the MPV remained constant in all age populations both in male and female.

Pediatric syringomyelia with chiari malformation: its clinical characteristics and surgical outcomes.

BACKGROUND: Most reports regarding pediatric syringomyelia have focused not only on Chiari malformation, but also on spinal dysraphism. However, the clinical characteristics of syringomyelia with spinal dysraphism are quite different from those of syringomyelia due to Chiari Type I malformation. The objectives of this study were to identify clinical characteristics of pediatric syringomyelia and to determine whether surgery prevents or corrects the scoliosis associated with syringomyelia. METHODS: We reviewed the records of 16 pediatric patients with syringomyelia and Chiari Type I malformation. The patients' ages ranged from 3 to 15 years, with mean age of 9.8 years. None of the patients had spinal dysraphism. RESULTS: Nystagmus was observed in 2 of the 16 patients, motor weakness in 8 patients, sensory disturbance in 10 patients, and scoliosis in 13 patients. As the initial surgical procedure, foramen magnum decompression (FMD) was performed in seven patients and syringo-subarachnoid (S-S) shunting in nine patients. The motor function improved in 7 of the 8 affected patients, and the sensory disturbance improved in 9 of the 10 affected patients. The magnetic resonance images obtained after the surgery revealed marked decrease of the syrinx size in all patients. Of the 13 patients with scoliosis, 5 showed improvement, 5 stabilization, and 3 deterioration. CONCLUSIONS: Compared with adolescent and adult syringomyelia, pediatric syringomyelia shows a much lower incidence of sensory disturbance and pain, but quite a high incidence of scoliosis. Surgery is effective in improving or stabilizing scoliosis in these patients.

Anterior approach to intramedullary hemangioblastoma: case report.

OBJECTIVE AND IMPORTANCE: Intramedullary spinal cord tumors are generally operated on by using the posterior approach. However, the posterior approach may not be suitable for a tumor in the anterior part of the spinal cord. In this report, we describe a case of a cervical intramedullary tumor that was successfully removed by using the anterior approach. CLINICAL PRESENTATION: A 48-year-old woman presented with lower cranial nerve disturbance and motor weakness of the upper extremities. Magnetic resonance imaging revealed a large extensive syrinx and an intramedullary enhanced tumor at the C6 level. The tumor was located at the left of the anterior part of the spinal cord. INTERVENTION: Based on these findings, the anterior approach was used in performing a corpectomy of C5 and C6. The tumor was highly vascular and was resected without resulting in any operative deficits. The pathological diagnosis was hemangioblastoma. CONCLUSION: The present case suggests that the anterior approach is an important option among surgical approaches to the intramedullary tumor in cases in which the tumors are small in size and are located in the anterior part of the cervical cord.

Analysis of optical signals evoked by peripheral nerve stimulation in rat somatosensory cortex: dynamic changes in hemoglobin concentration and oxygenation.

The origins of reflected light changes associated with neuronal activity (optical signals) were investigated in rat somatosensory cortex with optical imaging, microspectrophotometry, and laser-Doppler flowmetry, and dynamic changes in local hemoglobin concentration and oxygenation were focused on. Functional activation was carried out by 2-second, 5-Hz electrical stimulation of the hind limb under chloralose anesthesia. These measurements were performed at the contralateral parietal cortex through a thinned skull. Regional cortical blood flow (rCBF) started to rise 1.5 seconds after the stimulus onset, peaked at 3.5 seconds (26.7% +/- 9.7% increase over baseline), and returned to near baseline by 10 seconds. Optical signal responses at 577, 586, and 805 nm showed a monophasic increase in absorbance coincident with the increase in rCBF; however, the signal responses at 605 and 760 nm were biphasic (an early increase and late decrease in absorbance) and microanatomically heterogeneous. The spectral changes of absorbance indicated that the concentrations of both total hemoglobin and oxyhemoglobin increased together with rCBF; deoxyhemoglobin, increased slightly but distinctly (P = 0.016 at 1.0 seconds, P = 0.00038 at 1.5 seconds) just before rCBF increases, then decreased. The authors conclude that activity-related optical signals are greatly associated with a moment-to-moment adjustment of rCBF and metabolism to neuronal activity.

Diagnosis of spinal cord ependymoma and astrocytic tumours with magnetic resonance imaging.

Ependymoma and astrocytic tumours, both originating from the glial tissue, constitute the majority of intramedullary spinal cord tumours. The purpose of this study is to evaluate the diagnostic ability of magnetic resonance imaging (MRI) in these two types of intramedullary spinal cord tumours. MRI findings of 17 ependymomas and 11 astrocytic tumours of the spinal cord were reviewed. Pre-contrast T(1)-weighted images revealed abnormal enlargement of the spinal cord in all cases. Peritumoural cyst formation was noted in 14 ependymomas (82%) and four astrocytic tumours (36%). Evidence of haemorrhage was identified in five (29%) ependymomas and one (9%) astrocytic tumour. Gadolinium-MRI (Gd-MRI) revealed marked enhancement in 11 ependymomas (65%), while six ependymomas showed irregular, partial or no enhancement. Five of these six ependymomas had evidence of prior haemorrhage. Eight astrocytic tumours (73%) were enhanced on Gd-MRI and the pattern of enhancement was more irregular or partial than that of ependymomas. Two pilocytic astrocytomas showed marked ring-like enhancement. In conclusion, detection of haemorrhage and Gd-MRI will help to differentiate these two types of tumours. Further study will be needed to elucidate the relationship between the histological subtypes of the tumours and MRI findings. Copyright 1999 Harcourt Publishers Ltd.

Anterior approach for dumbbell type cervical neurinoma.

A one-stage anterior approach was performed in four patients for total removal of dumbbell type neurinoma at the cervical level. In each case, the neurinoma compressed the spinal cord in the cervical canal, developed anteriorly through the intervertebral foramen, and compressed the vertebral artery. A conventional cervical anterior approach at the tumor site was performed, followed by confirmation of the tumor located outside the spinal canal. After identification of the vertebral artery, corpectomy was carried out and the extradural component of the tumor was resected. In cases with a portion of the tumor located also within the dura mater, the dura mater was opened for removal of the intradural tumor. We found the anterior approach to be effective for the total removal of some kinds of cervical dumbbell type neurinomas.

A split cord malformation.

This report describes a case of split cord malformation without a septum. A 2-year-old boy presented with a 3-month history of neurogenic bladder. MRI did not show any apparent abnormality around the conus medullaris. However, CT myelography clearly demonstrated the presence of a split filum terminale. The patient underwent laminectomy of L1-5 laminas and untethering of the split filum terminale. CT myelography was superior to MRI in diagnosing split cord malformation in this case. As MRI is currently regarded as the superior imaging modality, this reported case may have been missed because the pathology was not apparent on MRI.

Spinal intrathecal actinomycosis: a case report.

BACKGROUND: Actinomycosis of the central nervous system is a rare disease that most frequently forms cerebral abscesses. In the present report, we describe an extremely rare case of spinal intrathecal actinomycosis. CASE PRESENTATION: A 33-year-old man presented with high fever followed by back pain and paraparesis. Magnetic resonance imaging (MRI) with gadolinium-diethylene-triamine penta-acetic acid (Gd-DTPA) enhancement (Gd-MRI) displayed an irregularly enhanced mass lesion at the thoraco-lumbar junction that mimicked an intramedullary tumor with exophytic growth. Surgical exploration 7 months after the onset of the high fever revealed intrathecal granulation tissue with small abscess formation. Another surgical exploration was carried out 2 months after the first operation because the patient developed progressive paraparesis and showed an intrathecal ring-like enhancement that was detected with Gd-MRI. Actinomyces organisms were finally identified histologically in the surgical specimen. CONCLUSIONS: The clinical course and serial changes of Gd-MRI findings are important considerations when this rare and infectious spinal lesion is suspected.