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.

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.

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.

The role of radiotherapy in the management of spinal cord glioma.

PURPOSE: To determine the role of radiotherapy in the management of spinal cord gliomas. METHODS AND MATERIALS: Thirty-six patients with spinal cord glioma treated between 1979 and 1993 were examined. The patients had 13 astrocytic tumors (7 astrocytomas, 4 anaplastic astrocytomas, 2 glioblastomas), 22 ependymal tumors (18 ependymomas, 4 myxopapillary ependymomas), and 1 unclassified glioma. Fifteen of the patients were treated by surgery alone, but the remaining 21 patients also received postoperative radiotherapy. Total resection was performed on 1 astrocytoma and 13 ependymomas. In general, 40-50 Gy/16-20 fractions/4-5 weeks were given after parital resection, but no radiotherapy was given after total resection. RESULTS: Actuarial survival was significantly better for patients with ependymal tumors than for those with astrocytic tumors (p = 0007), 5-year actuarial survival rates being 96% and 50% for patients with ependymal tumors and astrocytic tumors, respectively. For patients with ependymal tumors, there was no difference in motor function and survival between those with total resection and those with partial resection followed by radiotherapy. Actuarial 3-year survival was 80% for patients with astrocytomas and 40% for those with anaplastic astrocytomas plus glioblastomas. The difference in the degree of motor function between the patients treated with radiotherapy and those without radiotherapy was not statistically significant. One anaplastic astrocytoma and one glioblastoma patient have lived longer than 4 years after radical treatment including radiocordectomy, or irradiation using doses larger than the tolerance threshold of the spinal cord. CONCLUSION: Postoperative conventional radiotherapy is indicated after less than total resection of low-grade ependymal tumors and astrocytomas but not after total resection of ependymomas. Radiocordectomy may be an option for certain cases with high-grade astrocytic tumors.

Sensory evoked potentials for selective monitoring of the rat spinal cord: a cerebellar evoked potential to assess ventral cord integrity.

The purpose of this study was to evaluate two types of ascending sensory evoked potentials (SEPs) in the rat and their capacity for selective monitoring of dorsal versus ventral spinal cord integrity. SEPs were elicited by direct sciatic nerve stimulation. A cerebellar evoked response was recorded over the paramedian lobule of the cerebellar hemisphere (CEPpml) while somatosensory evoked potentials (SSEPs) were simultaneously recorded over the sensorimotor cortex. All components of the CEPpml and SSEP except the longest latency positive waves were present in each animal. At stimulus intensities of 3 to 10 mA, no significant changes in latency of the peaks were observed, but amplitudes of the longer latency responses tended to increase throughout this stimulation range. Unilateral sciatic stimulation resulted in bilateral cortical responses, larger ipsilaterally for the CEPpml, and contralaterally for the SSEP. Selective spinal cord lesions demonstrated N9 and P14 of the CEPpml to be mediated primarily through the ventral spinal cord, while P14 and N19 of the SSEP were conducted primarily through the dorsal columns. Sectioning of the cerebellar peduncles abolished N9 and P14 of the CEPpml despite persistence of the SSEP. This study demonstrates that selective assessment of the ventral and dorsal spinal cord is possible in the rat by monitoring SEPs.

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.

Three-dimensional analysis of the vascular system in the rat spinal cord with scanning electron microscopy of vascular corrosion casts. Part 2: Acute spinal cord injury.

The purpose of this study was to investigate the vascular mechanisms involved in the pathophysiology of acute spinal cord injury. Vascular corrosion casts of traumatized rat spinal cords at C7-T1 were inspected by scanning electron microscopy. Nineteen rats were subjected to a 51g acute clip compression at C8-T1 and then underwent transcardial perfusion with polyester resin at 15 minutes, 4 hours, or 24 hours after injury. The injured spinal cord appeared almost avascular at the compression site, although the large vessels on the surface of the spinal cord were all intact. The sulcal arteries at the injury site frequently showed constriction, and the impressions of endothelial nuclei were more slender and less distinct in the constricted arterial casts. Extravasation of the injected resin at the injury site was observed most frequently in the 15-minute group. Poorly filled distal branches of the sulcal arteries were seen at the injury site in every group. Indeed, it was concluded that the disruption and occlusion of the sulcal arteries and their branches accounted for a considerable amount of the posttraumatic ischemia of the cord. Occlusion of the sulcal arteries in the anterior median sulcus at the injury site was more frequently observed in the 24-hour group than in earlier groups. This observation suggests that there was a progressive circulatory disturbance of the damaged sulcal arteries at the injury site. The 4- and 24-hour groups showed avascular areas extending longitudinally from the injury site in the posterior columns, probably the result of hemorrhage and venous obstruction.

Three-dimensional analysis of the vascular system in the rat spinal cord with scanning electron microscopy of vascular corrosion casts. Part 1: Normal spinal cord.

Vascular corrosion casts of polyester resin in the normal spinal cord at C4-C6 and C7-T1 were inspected three-dimensionally by scanning electron microscopy in 13 rats. Arteries and veins were easily differentiated by the impression pattern of endothelial nuclei on the casts. The centrifugal arterial system from the sulcal arteries supplied most of the gray and white matter in the ventral and lateral spinal cord. Each sulcal artery supplied only one side of the cord. The average number of sulcal arteries was 2.6 per mm. The centripetal arterial system from the posterior spinal arteries fed the posterior gray and white matter. In contrast with classical concepts, there was no pial arterial plexus on the ventral and ventrolateral surface except for infrequent transverse branches from the anterior spinal artery. In the posterior columns, two types of large veins were identified: the posterior medial septal veins and the posterior oblique veins that drained the posterior columns, medial posterior gray matter, and posterior gray commissure. The remainder of the gray and white matter was drained by the sulcal veins and the radial veins. This method clearly demonstrates the three-dimensional structure of both the arterial and venous system in the rat spinal cord.

Silicone rubber microangiography of acute spinal cord injury in the rat.

The purpose of this study was to investigate the acute changes in the large vessels and microvasculature of the spinal cord after acute clip compression injury in the rat. Nineteen female Wistar rats underwent acute compression of the spinal cord at C8-T1 at 53 g for 1 min. Silicone rubber was injected into the ascending aorta at 15 minutes, 1, 4, or 24 hours after injury. An additional nine rats served as normal controls. The perfused spinal cords were cleared by the alcohol-methylsalicylate technique. The results showed that, in the normal rat, the centrifugal arterial system from the sulcal arteries provided the major blood supply to the gray matter and the lateral and ventral white matter extending all the way to the pial surface. In the normal rat, there were large veins in the posterior columns coursing longitudinally in the parasagittal plane at the base of the posterior columns. The injured spinal cords displayed marked ischemia and hemorrhage at the injury site. The hemorrhage predominated in the gray matter and posterior white columns and extended rostrally and caudally for 2 to 7 mm in each direction from the injury site. Remote hemorrhages originated from damage to the large parasagittal veins in the posterior columns. Extravasations of silicone rubber were frequently seen at the earlier posttraumatic times and often originated from the sulcal arteries or their branches at the injury site. Occluded sulcal arteries were identified at the injury site at 4 and 24 hours.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

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.

Surgical indication and results of foramen magnum decompression versus syringosubarachnoid shunting for syringomyelia associated with Chiari I malformation.

Several surgical procedures have been used for the treatment of syringomyelia associated with Chiari I malformation at our institute. The purpose of this article is to evaluate the results of two major surgical procedures, foramen magnum decompression (FMD) and syringosubarachnoid (SS) shunting. The series consisted of 70 patients with syringomyelia associated with Chiari I malformation who were surgically treated. Their ages ranged from 3 to 59 years (median, 29.4 yr). FMD was performed on 33 patients, and SS shunting was performed on 37 patients. The follow-up period ranged from 6 months to 12.5 years, with a mean of 60 months. The clinical and radiological outcomes were analyzed comparing the two groups. We principally performed FMD in patients with symptoms of Chiari I malformation and/or a small syrinx. We prefer to use SS shunting in patients with large syringes. Postoperative magnetic resonance imaging demonstrated that the syrinx had collapsed or decreased in size in 94% of the patients who underwent FMD and in 100% of the patients who underwent SS shunting. Neurological improvements were observed in 82% and in 97% of the patients who underwent FMD and SS shunting, respectively. In particular, the relief of pain was more fully achieved after SS shunting than after FMD. The average time for the syrinx to collapse was 6.3 weeks after surgery in the FMD group and 1.8 weeks in the SS shunting group. These results indicate that clinical symptoms and radiological findings improved much more quickly in the SS shunting group than in the FMD group.(ABSTRACT TRUNCATED AT 250 WORDS)

Magnetic resonance imaging in cases of spinal dural arteriovenous malformation.

Two patients with spinal dural arteriovenous malformations associated with intramedullary changes confirmed by the T2-weighted magnetic resonance imaging (MRI) scans are reported. The characteristics of the MRI findings for these 2 patients were as follows. 1) In the T2-weighted spin-echo image, intramedullary changes observed by MRI were visualized as a high signal intensity area at the level where delay in venous circulation of the spinal cord was revealed by the angiography of the spinal cord. 2) After the obliteration of the arteriovenous shunt by surgical management, intramedullary changes remarkably decreased and disappeared with the disappearance of swelling of the spinal cord observed preoperatively. After that, the atrophy of the spinal cord was shown. 3) The level, extent, and severity of intramedullary changes were decided by the condition of the level where the radiculospinal vein, as the flowing vein, refluxes into the coronal venous plexus and venous flow occurs through the radiculospinal vein into the epidural veins. We suspect that intramedullary changes shown by the T2-weighted MRI scan chiefly represent edema of the spinal cord, caused by an increase in venous pressure due to venous congestion of the spinal cord. MRI is a very useful diagnostic aid to detect intramedullary changes associated with a spinal dural arteriovenous malformation and to evaluate therapeutic results after surgery.

Spontaneous shrinkage of lumbosacral lipoma in conjunction with a general decrease in body fat: case report.

OBJECTIVE AND IMPORTANCE: We describe a rare case of a lumbosacral lipoma that shrank spontaneously in parallel to a general loss of body fat. Although early prophylactic surgery is generally recommended for lumbosacral lipomas, the observation made in this case may provide an important implication regarding the conservative management of this disorder. CLINICAL PRESENTATION: A 9-year-old male patient with a subcutaneous lipoma at the sacral level was found to have a lumbosacral lipoma in the spinal canal and tethered spinal cord, as revealed by magnetic resonance imaging. The patient showed no neurological or urological deficits, except for a mild pes cavus deformity. INTERVENTION: Follow-up magnetic resonance imaging performed 4 years later revealed a significant decrease in the size of the lumbosacral lipoma. The patient became very thin and showed no neurological deterioration during the follow-up period. The shrinkage of the lipoma was considered to be in association with the general loss of body fat. CONCLUSION: The control of body weight may be an important factor in the conservative management of patients with lumbosacral spinal lipomas.

Spinal cord evoked potential monitoring after spinal cord stimulation during surgery of spinal cord tumors.

Spinal cord evoked potentials (SCEPs) after spinal cord stimulation were used as a method of spinal cord monitoring during surgery of 6 extramedullary and 14 intramedullary spinal cord tumors. SCEPs were recorded from an epidural electrode placed rostral to the level of the tumor. Electrical stimulation was applied on the dorsal spinal cord from a caudally placed epidural electrode. The wave forms of SCEPs consisted of a sharp negative peak (N1) in 15 cases and two negative peaks (N1 and N2) in 5 cases. The N2 wave was markedly attenuated by posterior midline myelotomy, whereas the N1 activity showed less-remarkable changes by myelotomy. An increase in N1 amplitude was observed after the removal of the tumor in four extramedullary and three intramedullary cases. Of six patients that showed decreased N1 amplitude after the removal of the tumor, five patients developed postoperative motor deficits. However, there were four false-negative cases and one false-positive case in regard to changes of N1 amplitude and postoperative motor deficits. Four false results occurred in intramedullary cases. In two of them, postoperative symptoms indicated intraoperative unilateral damage to the spinal cord. The position of the stimulating electrode, the difference in thresholds of the axons for electrical stimulation between the right and left side of the spinal cord, or the change of the distance between the electrode and the spinal cord surface may account for these false results. Thus, our analysis of the changes of SCEP wave forms and early postoperative symptoms indicates that the sensitivity of this monitoring method to detect intraoperative insults to the spinal cord is unsatisfactory in spite of the reproducible wave forms. We conclude that SCEP monitoring can be used as an alternative method or in combination with other types of evoked potentials in patients with severe spinal cord lesions who show abnormal somatosensory evoked potentials preoperatively.

Vascular mechanisms in the pathophysiology of human spinal cord injury.

Vascular injury plays an important role in the primary and secondary injury mechanisms that cause damage to the acutely traumatized spinal cord. To understand the pathophysiology of human spinal cord injury, the authors investigated the vascular system in three uninjured human spinal cords using silicone rubber microangiography and analyzed the histological findings related to vascular injury in nine acutely traumatized human spinal cords obtained at autopsy. The interval from spinal cord injury to death ranged from 20 minutes to 9 months. The microangiograms of the uninjured human cervical cords demonstrated new information about the sulcal arterial system and the pial arteries. The centrifugal sulcal arterial system was found to supply all of the anterior gray matter, the anterior half of the posterior gray matter, approximately the inner half of the anterior and lateral white columns, and the anterior half of the posterior white columns. Traumatized spinal cord specimens in the acute stage (3-5 days postinjury) showed severe hemorrhages predominantly in the gray matter, but also in the white matter. The white matter surrounding the hemorrhagic gray matter showed a variety of lesions, including decreased staining, disrupted myelin, and axonal and periaxonal swelling. The white matter lesions extended far from the injury site, especially in the posterior columns. There was no evidence of complete occlusion of any of the larger arteries, including the anterior and posterior spinal arteries and the sulcal arteries. However, occluded intramedullary veins were identified in the degenerated posterior white columns. In the chronic stage (3-9 months postinjury), the injured segments showed major tissue loss with large cavitations, whereas both rostral and caudal remote sites showed well-demarcated necrotic areas indicative of infarction mainly in the posterior white columns. Obstruction of small intramedullary arteries and veins by the initial mechanical stress or secondary injury mechanisms most likely produced these extensive white matter lesions. Our studies implicate damage to the anterior sulcal arteries in causing the hemorrhagic necrosis and subsequent central myelomalacia at the injury site in acute spinal cord injury in humans.

Magnetic resonance imaging findings in ossification of the posterior longitudinal ligament of the cervical spine.

OBJECT: Because of the lack of magnetic resonance (MR) signal from cortical bones, MR imaging is inadequate for diagnosing ossified lesions in the spinal canal. However, MR imaging provides important information on spinal cord morphology and associated soft-tissue abnormality. The purpose of this study is to determine the role of MR imaging in the diagnosis and treatment of patients with ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. METHODS: The authors reviewed MR imaging findings in 42 patients with cervical OPLL who were examined with a superconducting MR imaging system. The types of OPLL reviewed included eight cases of continuous, 21 cases of segmental, and 13 cases of the mixed type. All patients were treated surgically either by anterior (26 cases) or posterior decompression (16 cases). CONCLUSIONS: The T1-weighted images clearly demonstrated the spinal cord deformity caused by OPLL. Associated disc protrusion was found to be present at the maximum compression level in 60% of the patients in this series. The highest incidence of disc protrusion (81%) was found in patients with segmental OPLL. Intramedullary hyperintensity on T2*-weighted imaging was noted in 18 patients (43%). The neurological deficits observed in these 18 patients were significantly more severe than those observed in the other 24 patients. Postoperative MR imaging revealed improvement in the spinal cord deformity, although the intramedullary hyperintensity was still observed in most cases. The present study demonstrates the importance of associated disc protrusion in the development of myelopathy in patients with cervical OPLL. Magnetic resonance imaging findings may be used to help determine the actual levels of spinal cord compression and to suggest the method of surgical treatment.

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.

Effect of a single huge dose of methylprednisolone on blood flow, evoked potentials, and histology after acute spinal cord injury in the rat.

Effects of a single, huge dose of methylprednisolone on post-traumatic spinal cord blood flow (SCBF), evoked potentials and histological changes were studied in a rat model of spinal cord injury. The purpose of this study was to assess the optimal dose of methylprednisolone for the treatment of rat spinal cord injury. Twenty-five male Wistar rats were subjected to an acute clip compression injury at 51 g for 1 min at C8-T1, and then received an intravenous bolus injection of one of the following 30 min after injury: vehicle, 30, 60, 120 or 240 mg kg-1 methylprednisolone. SCBF was measured at the injury site and an adjacent area with the hydrogen clearance technique. Sensory evoked potentials following sciatic stimulation were recorded from the somatosensory and cerebellar cortices. Descending volleys were recorded from T9-10 spinal cord following cerebellar stimulation. SCBF and evoked potential recordings were repeated until perfusion-fixation at 4 h after injury. After injury, SCBF at both levels significantly dropped, and all evoked potentials disappeared in all animals. None of the doses of methylprednisolone improved post-traumatic SCBF, or evoked potentials. Quantitative histological assessment of the injured cords revealed no significant differences in hemorrhages or cavitation in the spinal cord among the treatment groups. This study showed that a single huge dose of methylprednisolone from 30 to 240 mg kg-1 had no beneficial effects on the traumatized rat spinal cord in the acute stage.

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.