Role of magnesium in the reduction of ischemic depolarization and lesion volume after experimental subarachnoid hemorrhage

2002 ◽  
Vol 97 (2) ◽  
pp. 416-422 ◽  
Author(s):  
Walter M. van den Bergh ◽  
J. Karel Zuur ◽  
Niels A. Kamerling ◽  
Jan Thies H. van Asseldonk ◽  
Gabriël J. E. Rinkel ◽  
...  

Object. Ischemia-induced tissue depolarizations probably play an important role in the pathophysiology of cerebral ischemia caused by parent vessel occlusion. Their role in ischemia caused by subarachnoid hemorrhage (SAH) remains to be investigated. The authors determined whether ischemic depolarizations (IDs) or cortical spreading depressions (CSDs) occur after SAH, and how these relate to the extent of tissue injury measured on magnetic resonance (MR) images. In addition, they assessed whether administration of MgSO4 reduces depolarization time and lesion volume. Methods. By means of the endovascular suture model, experimental SAH was induced in 52 rats, of which 37 were appropriate for analysis, including four animals that underwent sham operations. Before induction of SAH, serum Mg++ levels were measured and 90 mg/kg intravascular MgSO4 or saline was given. Extracellular direct current potentials were continuously recorded from six Ag/AgCl electrodes, before and up to 90 minutes following SAH, after which serum Mg++ levels were again measured. Next, animals were transferred to the MR imaging magnet for diffusion-weighted (DW) MR imaging. Depolarization times per electrode were averaged to determine a mean depolarization time per animal. No depolarizations occurred in sham-operated animals. Ischemic depolarizations occurred at all electrodes in all animals after SAH. Only two animals displayed a single spreading depression-like depolarization. The mean duration of the ID time was 41 ± 25 minutes in the saline-treated controls and 31 ± 30 minutes in the Mg++-treated animals (difference 10 minutes; p = 0.31). Apparent diffusion coefficient (ADC) maps of tissue H2O, obtained using DW images approximately 2.5 hours after SAH induction, demonstrated hypointensities in both hemispheres, but predominantly in the ipsilateral cortex. No ADC abnormalities were found in sham-operated animals. The mean lesion volume, as defined on the basis of a significant ADC reduction, was 0.32 ± 0.42 ml in saline-treated controls and 0.11 ± 0.06 ml in Mg++-treated animals (difference 0.21 ml; p = 0.045). Serum Mg++ levels were significantly elevated in the Mg++-treated group. Conclusions. On the basis of their data, the authors suggest that CSDs play a minor role, if any, in the acute pathophysiology of SAH. Administration of Mg++ reduces the cerebral lesion volume that is present during the acute period after SAH. The neuroprotective value of Mg++ after SAH may, in part, be explained by a reduction in the duration of the ID of brain cells.

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 68-73 ◽  
Author(s):  
Pierre-Hugues Roche ◽  
Jean Régis ◽  
Henry Dufour ◽  
Henri-Dominique Fournier ◽  
Christine Delsanti ◽  
...  

Object. The authors sought to assess the functional tolerance and tumor control rate of cavernous sinus meningiomas treated by gamma knife radiosurgery (GKS). Methods. Between July 1992 and October 1998, 92 patients harboring benign cavernous sinus meningiomas underwent GKS. The present study is concerned with the first 80 consecutive patients (63 women and 17 men). Gamma knife radiosurgery was performed as an alternative to surgical removal in 50 cases and as an adjuvant to microsurgery in 30 cases. The mean patient age was 49 years (range 6–71 years). The mean tumor volume was 5.8 cm3 (range 0.9–18.6 cm3). On magnetic resonance (MR) imaging the tumor was confined in 66 cases and extensive in 14 cases. The mean prescription dose was 28 Gy (range 12–50 Gy), delivered with an average of eight isocenters (range two–18). The median peripheral isodose was 50% (range 30–70%). Patients were evaluated at 6 months, and at 1, 2, 3, 5, and 7 years after GKS. The median follow-up period was 30.5 months (range 12–79 months). Tumor stabilization after GKS was noted in 51 patients, tumor shrinkage in 25 patients, and enlargement in four patients requiring surgical removal in two cases. The 5-year actuarial progression-free survival was 92.8%. No new oculomotor deficit was observed. Among the 54 patients with oculomotor nerve deficits, 15 improved, eight recovered, and one worsened. Among the 13 patients with trigeminal neuralgia, one worsened (contemporary of tumor growing), five remained unchanged, four improved, and three recovered. In a patient with a remnant surrounding the optic nerve and preoperative low vision (3/10) the decision was to treat the lesion and deliberately sacrifice the residual visual acuity. Only one transient unexpected optic neuropathy has been observed. One case of delayed intracavernous carotid artery occlusion occurred 3 months after GKS, without permanent deficit. Another patient presented with partial complex seizures 18 months after GKS. All cases of tumor growth and neurological deficits observed after GKS occurred before the use of GammaPlan. Since the initiation of systematic use of stereotactic MR imaging and computer-assisted modern dose planning, no more side effects or cases of tumor growth have occurred. Conclusions. Gamma knife radiosurgery was found to be an effective low morbidity—related tool for the treatment of cavernous sinus meningioma. In a significant number of patients, oculomotor functional restoration was observed. The treatment appears to be an alternative to surgical removal of confined enclosed cavernous sinus meningioma and should be proposed as an adjuvant to surgery in case of extensive meningiomas.


2005 ◽  
Vol 102 (Special_Supplement) ◽  
pp. 262-265
Author(s):  
C. P. Yu ◽  
Joel Y. C. Cheung ◽  
Josie F. K. Chan ◽  
Samuel C. L. Leung ◽  
Robert T. K. Ho

Object. The authors analyzed the factors involved in determining prolonged survival (≥ 24 months) in patients with brain metastases treated by gamma knife surgery (GKS). Methods. Between 1995 and 2003, a total of 116 patients underwent 167 GKS procedures for brain metastases. There was no special case selection. Smaller and larger lesions were treated with different protocols. The mean patient age was 56.9 years, the mean number of initial lesions was 3.15, and the mean lesion volume was 10.45 cm.3 The mean follow-up time was 9.2 months. The median patient survival was 8.68 months. One-, 2-, 3-, 4-, and 5-year actuarial survival rates were 31.8%, 19.8%, 14.6%, 7.7%, and 6.9%, respectively. Patient age, number of lesions at presentation, and lesion volume had no influence on patient survival. Twenty-three (19.8%) patients survived for 24 months or more. Certain factors were associated with increased survival time. These were stable primary disease (21 of 23 patients), a long latency between diagnosis of the primary tumor and the occurrence of brain metastases (mean 28.4 months, median 16 months), absence of third-organ involvement, and repeated local procedures. Ten patients underwent repeated GKS (mean 3.4 per patient). Seven patients required open surgery for local treatment failures (recurrence or radiation necrosis). Two patients had both. Fifteen patients underwent repeated procedures. Conclusions. Aggressive local therapy with GKS, repeated GKS, and GKS plus surgery can achieve increased survival in a subgroup of patients with stable primary disease, no third-organ involvement, and long primary-brain secondary intervals.


2005 ◽  
Vol 102 ◽  
pp. 234-240 ◽  
Author(s):  
Chihiro Ohye ◽  
Tohru Shibazaki ◽  
Sumito Sato

Object.The authors studied the effects of gamma knife thalamotomy (GKT) on Parkinson disease-related tremor and essential tremor before and after reloading of radioactive cobalt.Methods.Based on experience in stereotactic thalamotomy aided by depth microrecording, the target was located at the lateral border of the thalamic ventralis intermedius nucleus (VIM). For more precise targeting, the percentage representation of the thalamic VIM in relation to the entire thalamic length is useful. The location of the target was determined on magnetic resonance (MR) imaging and computerized tomography scanning. A maximum dose of 130 Gy was delivered to the target by using a single isocenter with the 4-mm collimator. In more recent cases, a systematic follow-up examination was performed at 3, 6, 12, 18, and 24 months after GKT.Since 1993, the authors have treated 70 patients with PD. Throughout the series the same dosimetric technique has been used. The course after GKT was compared between the 25 cases with PD treated before reloading and the 35 cases treated after reloading. In the majority (80–85%) treated after reloading, tremor and rigidity were reduced around 6 months after GKT. In the cases treated before reloading this effect took approximately 1 year. The thalamic reaction on MR imaging showed the same two lesion types in both series: a restricted and a diffuse. After reloading the restricted lesion was more frequent and the lesion volume was smaller.Conclusions.The shorter delay in clinical improvement and smaller lesion size may be related to an increased radiation dose.


2002 ◽  
Vol 96 (6) ◽  
pp. 988-992 ◽  
Author(s):  
Veronica L. Chiang ◽  
Phillipe Gailloud ◽  
Kieran J. Murphy ◽  
Daniele Rigamonti ◽  
Rafael J. Tamargo

Object. The routine use of intraoperative angiography as an aid in the surgical treatment of aneurysms is uncommon. The advantages of the ability to visualize residual aneurysm or unintended occlusion of parent vessels intraoperatively must be weighed against the complications associated with repeated angiography and prolonged vascular access. The authors reviewed the results of their routine use of intraoperative angiography to determine its safety and efficacy. Methods. Prospectively gathered data from all aneurysm cases treated surgically between January 1996 and June 2000 were reviewed. A total of 303 operations were performed in 284 patients with aneurysms; 24 patients also underwent postoperative angiography. Findings on intraoperative angiographic studies prompted reexploration and clip readjustment in 37 (11%) of the 337 aneurysms clipped. Angiography revealed parent vessel occlusion in 10 cases (3%), residual aneurysm in 22 cases (6.5%), and both residual lesion and parent vessel occlusion in five cases (1.5%). When compared with subsequent postoperative imaging, false-negative results were found on two intraoperative angiograms (8.3%) and a false-positive result was found on one (4.2%). Postoperative angiograms obtained in both false-negative cases revealed residual anterior communicating artery aneurysms. Both of these aneurysms also subsequently rebled, requiring reoperation. In the group that underwent intraoperative angiography, in 303 operations eight patients (2.6%) suffered complications, of which only one was neurological. Conclusions. In the surgical treatment of intracranial aneurysms, the use of routine intraoperative angiography is safe and helpful in a significant number of cases, although it does not replace careful intraoperative inspection of the surgical field.


2003 ◽  
Vol 99 (6) ◽  
pp. 978-985 ◽  
Author(s):  
Chih-Lung Lin ◽  
Aaron S. Dumont ◽  
Ann-Shung Lieu ◽  
Chen-Po Yen ◽  
Shiuh-Lin Hwang ◽  
...  

Object. The reported incidence, timing, and predictive factors of perioperative seizures and epilepsy after subarachnoid hemorrhage (SAH) have differed considerably because of a lack of uniform definitions and variable follow-up periods. In this study the authors evaluate the incidence, temporal course, and predictive factors of perioperative seizures and epilepsy during long-term follow up of patients with SAH who underwent surgical treatment. Methods. Two hundred seventeen patients who survived more than 2 years after surgery for ruptured intracranial aneurysms were enrolled and retrospectively studied. Episodes were categorized into onset seizures (≤ 12 hours of initial hemorrhage), preoperative seizures, postoperative seizures, and late epilepsy, according to their timing. The mean follow-up time was 78.7 months (range 24–157 months). Forty-six patients (21.2%) had at least one seizure post-SAH. Seventeen patients (7.8%) had onset seizures, five (2.3%) had preoperative seizures, four (1.8%) had postoperative seizures, 21 (9.7%) had at least one seizure episode after the 1st week postoperatively, and late epilepsy developed in 15 (6.9%). One (3.8%) of 26 patients with perioperative seizures (onset, preoperative, or postoperative seizure) had late epilepsy at follow up. The mean latency between the operation and the onset of late epilepsy was 8.3 months (range 0.3–19 months). Younger age (< 40 years old), loss of consciousness of more than 1 hour at ictus, and Fisher Grade 3 or greater on computerized tomography scans proved to be significantly related to onset seizures. Onset seizure was also a significant predictor of persistent neurological deficits (Glasgow Outcome Scale Scores 2–4) at follow up. Factors associated with the development of late epilepsy were loss of consciousness of more than 1 hour at ictus and persistent postoperative neurological deficit. Conclusions. Although up to one fifth of patients experienced seizure(s) after SAH, more than half had seizure(s) during the perioperative period. The frequency of late epilepsy in patients with perioperative seizures (7.8%) was not significantly higher than those without such seizures (6.8%). Perioperative seizures did not recur frequently and were not a significant predictor for late epilepsy.


1992 ◽  
Vol 77 (1) ◽  
pp. 69-77 ◽  
Author(s):  
Michael G. Muhonen ◽  
Arnold H. Menezes ◽  
Paul D. Sawin ◽  
Stuart L. Weinstein

✓ A prospective study was undertaken in 1985 to better understand how the surgical manipulation of hind-brain herniation affected abnormal spinal curvature. Eleven patients under 16 years of age with Chiari malformation (not associated with myelodysplasia) and scoliosis of at least 15° were studied. The mean curve angle at the time of original treatment was 29°, with the convexity to the right in seven patients. The curvature was rapidly progressing in four patients. The most common presenting signs were myelopathy and weakness. Investigative procedures included spine radiographs with the patient standing and magnetic resonance (MR) imaging of the brain, spinal cord, and craniovertebral junction. Eight children had associated hydrosyringomyelia. Surgical intervention consisted of a dorsal posterior fossa decompression in all patients and a transoral ventral decompression of the cervicomedullary junction in five. All patients were followed at 3, 6, and 12 months, and at yearly intervals thereafter with clinical evaluations, spine radiographs in the standing position, and postoperative MR imaging. The mean follow-up period was 35 months. The scoliosis improved in eight patients, stabilized in one, and progressed in two. Only one child required postoperative spinal fusion and instrumentation for progression of scoliosis. Hematomyelia or hematobulbia was associated with persistent scoliosis in two patients. The presence of hydrosyringomyelia and bone erosion did not preclude curve improvement. All patients under 10 years of age had resolution of their scoliosis, despite preoperative curves of more than 40°. These findings emphasize the importance of early surgical intervention, with the restoration of normal cerebrospinal fluid dynamics at the craniovertebral junction in children with symptomatic Chiari malformations.


2003 ◽  
Vol 98 (6) ◽  
pp. 1235-1240 ◽  
Author(s):  
Mehmet A. Topcuoglu ◽  
Christopher S. Ogilvy ◽  
Bob S. Carter ◽  
Ferdinando S. Buonanno ◽  
Walter J. Koroshetz ◽  
...  

Object. The aim of this study was to assess the diagnostic yield of imaging tests performed in patients in whom the cause of subarachnoid hemorrhage (SAH) had not been demonstrated on initial angiography. Methods. By reviewing medical records of 806 patients with SAH who had been admitted during a 6.5-year period, the authors identified 86 in whom initial transfemoral catheter angiography failed to reveal the cause of SAH. Clinical and radiological data were analyzed to determine the diagnostic yield of subsequent catheter angiography, computerized tomography (CT) angiography, magnetic resonance (MR) angiography, and MR imaging of the brain and spine for various subtypes of SAH (bleeding not visualized on CT studies [CT-negative SAH], perimesencephalic SAH, and nonperimesencephalic SAH). Of 41 patients with nonperimesencephalic SAH, 36, 32, and 21 underwent repeated catheter angiography, CT angiography, and MR angiography, respectively; brain MR imaging was performed in 23 patients (18 with Gd and 15 with susceptibility contrast sequences), and spine MR imaging in 17. Of 36 patients with perimesencephalic SAH, 31, 23, and 17 underwent repeated catheter angiography, CT angiography, and MR angiography, respectively; brain MR imaging was performed in 18 patients (17 with Gd and 11 with susceptibility contrast sequences), and spine MR imaging in 14. Of nine patients with SAH not visualized on CT scanning, three, one, and six underwent repeated catheter angiography, CT angiography, and MR angiography, respectively; brain MR imaging was performed in eight patients (five with Gd and three with susceptibility contrast sequences), and spine MR imaging in seven. The cause of SAH could be determined in only four patients, all with nonperimesencephalic SAH. The only test that yielded a diagnosis was catheter angiography (three aneurysms on the second and one on the third angiography, all surgically secured). Diffusion-weighted MR imaging demonstrated small, deep infarcts in five patients. Conclusions. Repeated catheter angiography remains the most sensitive test to determine the cause of SAH that is not demonstrated on initial angiography, particularly in the subtype of nonperimesencephalic SAH. Newer, noninvasive imaging techniques provide little diagnostic yield.


2003 ◽  
Vol 99 (1) ◽  
pp. 23-30 ◽  
Author(s):  
Patrick P. Han ◽  
Felipe C. Albuquerque ◽  
Francisco A. Ponce ◽  
Christopher I. Mackay ◽  
Joseph M. Zabramski ◽  
...  

Object. Intracranial stent placement combined with coil embolization is an emerging procedure for the treatment of intracranial aneurysms. The authors report their results using intracranial stents for the treatment of intracranial aneurysms. Methods. A prospectively maintained database was reviewed to identify all patients with intracranial aneurysms that were treated with intracranial stents. Ten lesions, including eight broad-based aneurysms and two dissecting aneurysms, were treated in 10 patients. Four lesions were located in the cavernous segment of the internal carotid artery, two at the vertebrobasilar junction, two at the basilar trunk, one at the basilar apex, and one in the intracranial vertebral artery. Attempts were made to place stents in 13 patients, but in three the stents could not be delivered. Altogether, intracranial stents were placed in 10 patients for 10 lesions. Results that were determined to be satisfactory angiographically were achieved in all 10 lesions. Two patients suffered permanent neurological deterioration related to stent placement. In two patients, the aneurysm recurred after stent-assisted coil embolization. In one case of recurrence a second attempt at coil embolization was successful, whereas in the second case of recurrence parent vessel occlusion was required and well tolerated. Conclusions. Intracranial stents can be a useful addition to coil embolization by providing mechanical, hemodynamic, and visual benefits in the treatment of complex, broad-based aneurysms.


1999 ◽  
Vol 91 (1) ◽  
pp. 54-59 ◽  
Author(s):  
Mark D. D'Alise ◽  
Edward C. Benzel ◽  
Blaine L. Hart

Object. Confirmation of cervical spine stability is difficult to obtain in the comatose or obtunded trauma patient. Concurrent therapies such as endotracheal intubation and the application of rigid cervical collars diminish the utility of plain radiographs. Bony as well as supportive soft-tissue structures must be evaluated before the cervical spine can be determined to be uninjured. Although major injuries to extradural soft-tissue structures in the awake trauma patient are frequently excluded by physical examination, when the patient is obtunded the physical examination may be unreliable. Therefore, an enhanced diagnostic method for the evaluation of soft-tissue injury is desirable. The authors conducted a study in which magnetic resonance (MR) imaging was used as such a method to assess posttraumatic spinal stability in the comatose or obtunded patient. Methods. Early, limited (sagittal T1- and T2-weighted) MR imaging was performed posttruama in 121 patients to assess soft-tissue injury. In all patients the mechanism of injury potentially could be associated with cervical spine instability, and each patient was endotracheally intubated because of head injury or severe multisystem injuries. All patients underwent imaging studies within 48 hours of injury and were either treated or cleared and spinal precautions were discontinued. Patients were excluded from this study if they had an obvious cervical spine injury identified on the initial radiographic studies or if they were determined to be too medically unstable to undergo MR imaging within the acute period (<48 hours postinjury). Thirty-one (25.6%) of the 121 patients were found to have sustained significant injury to the paravertebral ligamentous structures, the disc interspace, or the bony cervical spine. These injuries were undetected by plain radiography. The other 90 patients (74.4%) were determined within 48 hours not to have sustained a soft-tissue injury. Eight patients (6.6%) ultimately underwent surgery to treat the cervical spine injury, and MR imaging was the first test that identified the injury in each of these patients. There were no complications related to imaging procedures. Conclusions. Sagittal T1- and T2-weighted MR imaging appears to be a safe, reliable method for evaluating the cervical spine for nonapparent injury in comatose or obtunded trauma patients. In the early postinjury period, nursing and medical care are thereby facilitated for patients in whom occult injury to the spine is ruled out and for whom those attendant precautions are unnecessary.


2005 ◽  
Vol 102 ◽  
pp. 262-265 ◽  
Author(s):  
C. P. Yu ◽  
Joel Y. C. Cheung ◽  
Josie F. K. Chan ◽  
Samuel C. L. Leung ◽  
Robert T. K. Ho

Object.The authors analyzed the factors involved in determining prolonged survival (≥ 24 months) in patients with brain metastases treated by gamma knife surgery (GKS).Methods.Between 1995 and 2003, a total of 116 patients underwent 167 GKS procedures for brain metastases. There was no special case selection. Smaller and larger lesions were treated with different protocols. The mean patient age was 56.9 years, the mean number of initial lesions was 3.15, and the mean lesion volume was 10.45 cm.3The mean follow-up time was 9.2 months.The median patient survival was 8.68 months. One-, 2-, 3-, 4-, and 5-year actuarial survival rates were 31.8%, 19.8%, 14.6%, 7.7%, and 6.9%, respectively. Patient age, number of lesions at presentation, and lesion volume had no influence on patient survival. Twenty-three (19.8%) patients survived for 24 months or more. Certain factors were associated with increased survival time. These were stable primary disease (21 of 23 patients), a long latency between diagnosis of the primary tumor and the occurrence of brain metastases (mean 28.4 months, median 16 months), absence of third-organ involvement, and repeated local procedures. Ten patients underwent repeated GKS (mean 3.4 per patient). Seven patients required open surgery for local treatment failures (recurrence or radiation necrosis). Two patients had both. Fifteen patients underwent repeated procedures.Conclusions.Aggressive local therapy with GKS, repeated GKS, and GKS plus surgery can achieve increased survival in a subgroup of patients with stable primary disease, no third-organ involvement, and long primary-brain secondary intervals.


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