bluuebunny/crossref_metadata_2025 huggingface dataset:
Hemorrhagic dilation of the fourth ventricle: an ominous predictor
Authors: Shapiro Scott A. , Campbell Robert L. , Scully Thomas
Published: May 2009

✓ Very little is known about the effect of computerized tomography (CT)-documented fourth intraventricular hemorrhage (IVH). An analysis of 50 patients with CT-documented fourth IVH treated between 1987 and 1992 is presented. The various etiologies included intraparenchymal hemorrhage with secondary fourth IVH (19 cases), spontaneous subarachnoid hemorrhage (18 cases), spontaneous IVH (seven cases), and trauma (six cases). Overall, 28 patients (56%) had hemorrhagic dilation of the fourth ventricle and all 28 suffered brain death, despite aggressive therapy in 79% of cases. Twenty-two patients (44%) had fourth IVH without dilation; of these, nine (41%) died and 13 (59%) experienced functional survival, despite aggressive care in 90% of cases. The survival rate was significantly worse for patients with dilation of the fourth ventricle (p < 0.01, chi-squared test). Of the 28 patients with fourth IVH associated with dilation, 25 (89%) had diffuse clot, involving the lateral and third ventricles as well, and three (11%) had isolated fourth IVH. Of the 22 patients with fourth IVH and no dilation, 13 (59%) had diffuse IVH (eight of these died and five had functional recovery) and nine (41%) had isolated fourth IVH (one died and eight had functional recovery). Diffuse ventricular clot was associated with an increased mortality rate for patients with fourth IVH and no dilation (p < 0.05).

Of the 28 patients with fourth IVH associated with dilation, 24 (86%) presented with a Glasgow Coma Scale (GCS) score of 3 or 4, one with a GCS score of 6, and three with a GCS score of 13 to 15; all 28 died. For the 22 patients with fourth IVH and no dilation, nine presented with a GCS score of 3 to 5 (eight died and one had functional recovery), three had a GCS score of 6 to 8 (all three had functional survival), two had a GCS score of 9 to 12 (both had functional survival), and eight had a GCS score of 13 to 15 (one died and seven had functional survival). There was a greater chance of higher GCS scores in patients with fourth IVH and no hemorrhagic dilation (p < 0.01). Logistic regression multivariate analysis showed hemorrhagic fourth ventricular dilation to be the most significant outcome predictor (p = 0.0001), followed by GCS score (p = 0.007) and the presence of diffuse IVH (p = 0.0279).
Resective surgery for medically intractable epilepsy associated with schizencephaly
Authors: Silbergeld Daniel L. , Miller John W.
Published: May 2009

✓ Four adults with unilateral (three cases) or bilateral (one case) closed schizencephaly, medically intractable epilepsy, and otherwise normal neurological examinations are presented. Three were examined preoperatively with magnetic resonance imaging and one with computerized tomography. Scalp electroencephalographic (EEG) studies in all four patients and electrocorticography via intracranial electrodes in two showed seizure origin in the cleft regions in two patients and in the ipsilateral temporal lobe in the other two. Temporal lobectomy was performed in the two patients with temporal lobe foci. Resection of superficial pachygyria around the cleft was performed in one patient. The authors conclude that the abnormal cortical mantle lining schizencephalic clefts may be epileptogenic. Alternatively, temporal allocortex may become the source of seizures. Therefore, these patients require careful EEG monitoring of the entire ipsilateral hemisphere as well as the cleft region.
Continuous monitoring of jugular bulb oxygen saturation as a measure of the shunt flow of cerebral arteriovenous malformations
Authors: Katayama Yoichi , Tsubokawa Takashi , Hirayama Teruyasu , Himi Kazuhisa
Published: May 2009

✓ Jugular bulb oxygen saturation (SjO2) was monitored during preoperative embolization procedures in a consecutive series of 15 patients with large supratentorial arteriovenous malformations (AVM's) in order to test the hypothesis that changes in the shunt flow ratio can be continuously evaluated from the SjO2. A fiberoptic catheter was placed at the dominant jugular bulb. The SjO2 measured using jugular blood withdrawn before embolization was significantly higher than the SjO2 measured at the end of the final embolization procedure (mean ± standard deviation 84.1% ± 12.7% vs. 74.2% ± 10.9%, p < 0.0001), showing a positive correlation with the AVM volume (r = 0.66, p < 0.001). Continuous monitoring of SjO2 via the fiberoptic catheter revealed a progressive decrease in association with the embolization procedures. Microsurgical resection of the AVM was performed at 1 to 2 weeks after the final embolization. Cases in which postoperative hemispheric deformation was revealed on computerized tomography demonstrated a higher SjO2 at the end of embolization compared to that in the remaining cases (81.6% ± 8.6% vs. 67.8% ± 8.4%, p < 0.008). Hemispheric deformation was observed in all cases in which the SjO2 did not decline to a level below 90% following embolization. The risk of severe hyperemic complications appeared to be greatly diminished when the SjO2 fell to below 80%. Assuming that the oxygen saturation of the perfusion flow (SjpO2) ranges from 50% to 75%, the ratio of the shunt flow to total flow at an SjO2 of 90% was estimated to be 0.6 to 0.8 based on the following equation: shunt flow/(perfusion flow + shunt flow) = (SjO2 − SjpO2)/(arterial oxygen saturation − SjpO2). These results suggest that monitoring the SjO2 provides real-time information concerning the progress of embolization and helps to determine whether the embolization has progressed sufficiently to avoid postoperative hyperemic complications.
Ventricular entry during resection of malignant gliomas: effect on intracranial cerebrospinal fluid tumor dissemination
Authors: Elliott J. Paul , Keles G. Evren , Waite Michael , Temkin Nancy , Berger Mitchel S.
Published: May 2009

✓ The ventricular system is not infrequently entered during the course of maximum cytoreductive surgery for high-grade supratentorial gliomas. It is unclear if ventricular entry during surgery and/or proximity of the tumor to the ventricular system affects cerebrospinal fluid (CSF) tumor dissemination or the patients' overall survival rate. The authors retrospectively reviewed hospital records and neuroradiological studies of 51 patients operated on at the University of Washington between 1987 and 1991. Inclusion in this study necessitated a pathological diagnosis of malignant glioma and the availability of preoperative and postoperative computerized tomography scans or magnetic resonance images. Patients were excluded from the study if they had radiographic evidence of ventricular entry or CSF tumor dissemination prior to referral to the authors' institution. The index operation was defined as the first operation at the University of Washington or (in those patients with ventricular entry) the operation in which the ventricle was entered. Patients were followed until time of death or, in the case of survivors, until February, 1992. The effect of both ventricular entry and the proximity of the tumor to the ventricular system on CSF tumor dissemination and survival rate was assessed using statistical survival methodology.

There was no significant difference in time from diagnosis to the index operation between groups compared (Mann-Whitney U-test, p > 0.40). Cerebrospinal fluid dissemination was radiographically documented in 18 patients (35%) following the index operation. This occurrence was not significantly influenced by either ventricular entry during surgery (Mantel-Cox test, p = 0.13), the proximity of the tumor to the ventricular system (p = 0.63), or these two variables combined (p = 0.28). Survival rate following the index operation was not significantly affected by ventricular entry (p = 0.66), proximity of the tumor to the ventricular system (p = 0.61), or these two variable considered in combination (p = 0.44). However, survival rate was significantly decreased once CSF tumor dissemination had occurred (Cox model, p = 0.03).
Preoperative localization of the central sulcus by dipole source analysis of early somatosensory evoked potentials and three-dimensional magnetic resonance imaging
Authors: Buchner Helmut , Adams Ludwig , Knepper Achim , Rüger Rainer , Laborde Gabriel , Gilsbach Joachim M. , Ludwig Irene , Reul Jürgen , Scherg Michael
Published: May 2009

✓ Surgery of lesions within or close to the central area of the brain always carries the risk of iatrogenic motor or sensory deficits. Functional localization by means of intraoperative direct stimulation of the motor area or by recording somatosensory evoked potentials (SSEP's) from the surface of the somatosensory cortex is believed to reduce the operative risk. The authors introduce the combination of dipole source analysis of scalp-recorded SSEP's with three-dimensional (3-D) magnetic resonance (MR) imaging as a tool for preoperative localization of the central sulcus. This provides information on both functional and structural localization for preoperative planning.

Four repeated measurements of right and left median nerve SSEP's were obtained from 20 subjects. Dipole source analysis showed a retest reliability of the 3-D localization error of 2.9 ± 2.0 mm. Compared to the MR evaluation, dipole source analysis was found to mark the central sulcus within 3 mm for 15 conditions (subjects × side of stimulation), while the 3-D MR measurement was accurate to within 6 mm for 10 conditions and 9 mm for 14 conditions. Dipole locations were confirmed in six patients who underwent surgery of the central region.

With respect to this application, dipole source analysis combined with 3-D MR imaging appears to be a valuable tool for preoperative functional localization. The accuracy in localization will be further improved when realistic head models become available that can take into account individual head geometry. Further development of the proposed new method holds promise that evoked potentials and electroencephalography will gain greater use in presurgical functional localization.
Prognostic scoring in adult astrocytic tumors using patient age, histopathological grade, and DNA histogram type
Authors: Salmon Isabelle , Dewitte Olivier , Pasteels Jean-Lambert , Flament-Durand Jacqueline , Brotchi Jacques , Vereerstraeten Pierre , Kiss Robert
Published: May 2009

✓ High-grade astrocytic tumors constitute the most serious as well as the most common group of primary brain tumors. Although several prognostic factors have been proposed, little is known about the prognostic value of deoxyribonucleic acid (DNA) ploidy in adult astrocytic tumors. In a series of 146 adult patients, aged 16 to 82 years, the individual prognostic values of six variables were studied, namely: tumor histopathological grade, treatment, patient age, extent of tumor, ploidy level, and DNA histogram type. Cox's proportional hazard model was then applied to the data to ascertain which factors might independently determine patient survival. Univariate analyses revealed that histopathological grade, age, and DNA histogram type were very powerful prognostic factors. The statistical significance of the influence of adjuvant radiotherapy and chemotherapy was at a borderline level, and the two remaining variables (tumor extent and ploidy level) had no prognostic relevance. Multivariate analyses showed that age, histopathological grade, and DNA histogram type were independent, statistically significant prognostic factors.

A prognostic score was calculated from Cox's polynomial function in which those factors were introduced. The best score corresponded to a patient aged 16 years with a hypertriploid low-grade astrocytoma, while the worst score corresponded to a patient aged 82 years with a diploid high-grade astrocytoma. The worst score:best score ratio revealed a risk 71 times higher for a bad prognosis. It is concluded that patient age, histopathological grade, and DNA histogram type are very powerful prognostic factors for adult astrocytic tumors. A prognostic score including those factors could be used to characterize astrocytic tumor aggressiveness presurgically on fine-needle aspirates, and to monitor the patient's postsurgical evolution to define the appropriate therapy.
Intracranial dissection of the distal middle cerebral artery as an uncommon cause of distal cerebral artery aneurysm
Authors: Piepgras David G. , McGrail Kevin M. , Tazelaar Henry D.
Published: May 2009

✓ An aneurysmal dissection of a right middle cerebral artery (MCA) branch is described in a 56-year-old woman. The abnormality was an incidental finding on computerized tomography and subsequently appeared on magnetic resonance imaging performed to evaluate the patient for subjective pulsatile tinnitus. The intracranial aneurysm was documented to have enlarged on serial angiography over a 6-week interval. Treatment was believed to be necessary because of the unknown etiology of the aneurysm, with the differential diagnosis including mycotic or neoplastic aneurysm with a risk of hemorrhage. The lesion was excised and flow to the distal MCA branch was preserved with an anastomosis of the superficial temporal artery to the MCA. The aneurysm, which developed at the level of the sylvian fissure, proved on pathological study to be related to a focal dissection of the MCA branch. The radiographic appearance and pathological findings are presented. Focal dissection must henceforth be included in the differential diagnosis of peripheral cerebral artery aneurysms.
Intraspinal mesenchymal chondrosarcoma
Authors: Ranjan Alok , Chacko Geeta , Joseph Thomas , Chandi Sushil M.
Published: May 2009

✓ A 52-year-old man presented with symptoms of progressive cervical radiculomyelopathy. A myelogram showed an intradural block at the C-6 level. Magnetic resonance T1-weighted imaging revealed a hypointense, sausage-shaped mass extending from C-3 to C-6, located posterolaterally on the right side and pushing the spinal cord to the left and anteriorly. At surgery, a mass was found attached solely to the pia mater, with a normal arachnoid and dura mater overlying it. The mass was excised completely and microscopic examination identified a mesenchymal chondrosarcoma. The patient was symptom-free 6 months after surgery.
Assessment of bladder function after lumbar decompressive laminectomy for spinal stenosis: a prospective study
Authors: Deen H. Gordon , Zimmerman Richard S. , Swanson Scott K. , Larson Thayne R.
Published: May 2009

✓ Lumbar spinal stenosis is a common problem in elderly patients. In its more advanced forms, it typically causes intractable leg pain, but many patients also manifest varying degrees of bladder dysfunction. The goal of lumbar decompressive laminectomy is relief of leg pain and paresthesias, yet some patients also achieve improvement in bladder function. This study prospectively investigated patients with lumbar spinal stenosis to determine whether laminectomy had any effect on urological function. Of the 20 patients in the study, 10 were men and 10 women (average age 70.9 years). All patients had severe lumbar stenosis affecting between two and four spinal segments, and all reported some degree of bladder dysfunction. Cystoscopy and urodynamic testing were completed preoperatively. A standard decompressive laminectomy was performed over the appropriate number of spinal segments. Urodynamic studies were repeated at 2 and 6 months postoperatively. At the 6-month follow-up review, bladder function was subjectively improved in 12 patients (60%) and unchanged in eight (40%). Postvoiding residual urine volume was the urodynamic factor most likely to be improved by laminectomy. In nine patients (45%), baseline postvoiding residual urine volume was elevated and all nine had improvement postoperatively. In the remaining 11 patients (55%), this urine volume was normal before and after surgery. Maximum urine flow rates also improved, but the results of cytometrography and electromyography, urine flow pattern, and bladder capacity were unchanged postoperatively. Cystoscopy detected previously undiagnosed malignancy of the lower urinary tract in two patients (10%). It is concluded that lumbar decompressive laminectomy can have a beneficial effect on bladder function in a significant number of patients with advanced lumbar spinal stenosis.
Temporary vessel occlusion in spontaneously hypertensive and normotensive rats
Authors: Selman Warren R. , Bhatti Sana U. , Rosenstein C. Cory , Lust W. David , Ratcheson Robert A.
Published: May 2009

✓ Temporary occlusion of an intracranial artery is frequently necessary in the surgical management of intracranial aneurysms, arteriovenous malformations, and tumors. While the risks of vessel damage associated with clip application have been lessened by improved design, the threat of ischemic damage remains. It is unclear whether multiple, brief periods of clip application are more or less safe than a single period of occlusion, and whether the underlying cerebrovascular status influences the outcome from either method.

The effect of each of these paradigms (single: 1-hour occlusion; multiple: three 20-minute episodes separated by 10 minutes of reperfusion) on histopathological outcome was assessed in a middle cerebral artery (MCA) occlusion model using both normotensive and spontaneously hypertensive rats. The mean volume of infarction (± standard error of the mean) was not different between the single-ischemic (49.4 ± 17.3 cu mm) and the multiple-ischemic (42.9 ± 12.9 cu mm) episode groups of normotensive rats, whereas in the spontaneously hypertensive rats a significant difference existed between the volume of infarction for the single-occlusion group (126.7 ± 18.7 cu mm) and the multiple-occlusion group (162.4 ± 15.5 cu mm) (p < 0.05). The metabolic data obtained from spontaneously hypertensive animals did not provide an explanation for the larger infarction in that there were no significant differences between the single- and multiple-occlusion groups with respect to tissue glucose, adenosine triphosphate, or lactate levels. The results suggest that intermittent reperfusion may have different effects depending not only on the degree and duration of ischemia and reperfusion, but also on the underlying cerebrovascular status.
Familial occurrence of subependymoma
Authors: Ryken Timothy C. , Robinson Robert A. , VanGilder John C.
Published: May 2009

✓ Subependymomas are unusual tumors believed to arise from the bipotential subependymal cell. Previous reports of familial occurrence of subependymoma have involved monozygous twins and siblings. The authors describe the first reported occurrence of fourth ventricular subependymoma in a father and son, suggesting the possibility of direct inheritance.
Retirement of Mrs. Jean Lawe, Managing Editor of the Journal of Neurosurgery
Authors: Sundt Thoralf M.
Published: May 2009

✓ On June 30, Mrs. Jean Lawe will step down as Managing Editor of the Journal of Neurosurgery. She has worked on the Journal since 1965, when Dr. Louise Eisenhardt retired as the first Editor. Since that time the Journal has grown in size and circulation, and production has become fully computerized. In her valedictory, Mrs. Lawe summarizes her years with the Journal and her approach to scientific editing.
Microvascular decompression for trigeminal neuralgia caused by vertebrobasilar compression
Authors: Linskey Mark E. , Jho Hae Dong , Jannetta Peter J.
Published: May 2009

✓ Thirty-one (2%) of 1404 consecutive patients with typical trigeminal neuralgia who underwent microvascular decompression between 1972 and 1993 were found to have vascular compression by the vertebral artery (VA) or the basilar artery (BA). Compared to the remaining 1373 patients, this subgroup was older (mean age 62 vs. 55 years, p < 0.001), was predominantly male (68% vs. 39%, p < 0.002), demonstrated left-sided predominance (65% vs. 39%, p < 0.002), was more likely to be hypertensive (65% vs. 18%, p < 0.001), and was more likely to have ipsilateral hemifacial spasm (16% vs. 0.6%, p < 0.001). The trigeminal nerve was compressed by the VA in 18 cases (the VA alone in three and the VA plus other vessels in 15), the BA in 12 cases (the BA alone in four and the BA plus other vessels in eight), and the vertebrobasilar junction in one case. Twenty-nine of the 31 patients underwent vascular decompression of the trigeminal nerve, one had a complete trigeminal root section, and one underwent partial root section with vascular decompression of the remaining nerve.

All 31 patients were pain-free, off medication immediately after surgery, and this pain-free, medication-free status was maintained at 1 year after surgery in 96% of cases, at 3 years in 92%, and at 10 years in 86%, based on life-table analysis. Minor trigeminal hypesthesia/hypalgesia was present preoperatively in 52%. New or worsened minor hypesthesia/hypalgesia developed in 41% of patients, while transient diplopia as well as hearing loss developed in 23% and 13% in the overall series, respectively. No patient developed major trigeminal sensory loss or masseter weakness after vascular decompression alone. There was no operative mortality. Vascular decompression is an effective treatment for patients with trigeminal neuralgia who have vertebrobasilar compression of the trigeminal nerve. Patients should be warned that decompression of a tortuous vertebrobasilar system carries a higher risk of mild trigeminal dysfunction, diplopia, and hearing loss than standard microvascular decompression.
Cytotoxic effects of bloody cerebrospinal fluid on cerebral endothelial cells in culture
Authors: Foley Patricia L. , Takenaka Katsunobu , Kassell Neal F. , Lee Kevin S.
Published: May 2009

✓ The release of intracellular products from lysed blood cells is believed to play a critical role in the etiology of vascular pathology following intracerebral hemorrhage. The present studies investigated the effects of a mixture of blood and cerebrospinal fluid (CSF) on bovine intracranial endothelial cells maintained in culture. The incorporation of 3H-leucine into endothelial cells was used as an index of cellular viability. Cerebrospinal fluid alone did not alter the incorporation of 3H-leucine into the cells. In contrast, CSF preincubated with blood for 3 days or longer prior to treatment elicited significant reductions in leucine incorporation. Treatment with CSF preincubated with blood for 5 to 7 days resulted in the rapid deterioration of the culture, with large numbers of cells detaching almost immediately. Concentrations of hemoglobin were elevated profoundly in mixtures of blood and CSF preincubated for periods longer than 3 days. The increases in hemoglobin concentration were related temporally to increases in the cytotoxic impact of the bloody CSF.

These findings suggest that factors released during the breakdown of blood exert a deleterious effect on intracranial endothelial cells. The time course of this effect is closely related to the development of vasospasm in humans following subarachnoid hemorrhage. Taken together, these observations are consistent with the hypothesis that intracellular blood products, particularly hemoglobin, contribute to vasospasm by directly compromising endothelial function.
Experimental intracerebral hemorrhage: relationship between brain edema, blood flow, and blood-brain barrier permeability in rats
Authors: Yang Guo-Yuan , Betz A. Lorris , Chenevert Thomas L. , Brunberg James A. , Hoff Julian T.
Published: May 2009

✓ There have been few investigations of brain edema formation after intracerebral hemorrhage (ICH), despite the fact that mass effect and edema are important clinical complications. The present study was designed to investigate the time course for the formation and resolution of brain edema and to determine how changes in cerebral blood flow (CBF) and blood-brain barrier (BBB) permeability are temporally related to edema formation following ICH.

Anesthetized adult rats received a sterile injection of 100µl of autologous blood into the caudate nucleus. Water and ion contents were measured immediately, at 4 and 12 hours, and daily to Day 7 (10 time points, six rats at each time) after experimental ICH. The water content of the ipsilateral basal ganglia increased progressively (p < 0.002) over the first 24 hours, then remained constant until after Day 5, when the edema began to resolve. Edema was most severe in the tissue immediately surrounding the hemorrhage; however, it was also present in the ipsilateral cortex, the contralateral cortex, and the basal ganglia. Measurements of local CBF (using [14C]-iodoantipyrine) and BBB permeability (using [3H]-α-aminoisobutyric acid) were obtained in separate groups of six to eight rats at various time intervals between 1 and 48 hours after ICH. Cerebral blood flow was reduced to 50% of control at 1 hour, returned to control values by 4 hours, but then decreased to less than 50% of control between 24 and 48 hours after ICH. The BBB permeability increased significantly prior to the occurrence of significant edema in the tissue surrounding the clot. However, BBB permeability in the more distant structures remained normal despite the development of edema.

These results demonstrate a time course for the formation and resolution of brain edema following ICH similar to that observed during focal ischemia. Brain edema forms in the immediate vicinity of the clot as a result of both BBB disruption and the local generation of osmotically active substances and then spreads to adjacent structures. While local ischemia, due to the mass effect of the hemorrhage, may play a role in producing cytotoxic and vasogenic edema, the release of toxic substances from the clot should also be considered. Since edema is nearly maximal by 24 hours after ICH, therapy directed at reducing edema formation must be instituted within the 1st day.
Hindbrain herniation: an unusual occurrence after shunting an intracranial arachnoid cyst
Authors: Hassounah Maher I. , Rahm Bengt E.
Published: May 2009

✓ The case is presented of a prepontine arachnoid cyst in a 28-year-old woman. She was treated by craniotomy, stereotactic aspiration, internal shunting, and finally by insertion of a cystoperitoneal shunt. Eight months later she developed an asymptomatic Arnold-Chiari type I malformation. The pathogenesis of this unusual hindbrain herniation is explained on the basis of the differential pressure between two compartments and cephalocranial disproportion.
The Journal of Neurosurgery in the computer era
Authors: Collins William F.
Published: May 2009

✓ The fourth Editor of the Journal of Neurosurgery offers short vignettes on the Editors who preceded and succeeded him. He recounts some of the challenges that were faced and changes that were made during his time as Editor. One of the major changes was production of the Journal via computer.
Hormone receptors in initially excised versus recurrent intracranial meningiomas
Authors: Rubinstein Abraham B. , Loven David , Geier Abraham , Reichenthal Eli , Gadoth Natan
Published: May 2009

✓ Intracranial meningiomas from 51 surgical patients consecutively treated during an 18-month period were evaluated for the presence of receptors to progesterone and estrogen. Thirty-eight patients underwent initial resection during this time and 13 underwent reoperation for recurrent disease. With positivity defined as receptor levels greater than 10 fmol/mg of cytosol protein, 84% of all the meningiomas were positive for progesterone receptors, whereas only 33% were positive for estrogen receptors. Among the recurrent meningiomas, 92% showed evidence of progesterone receptors and 54% of estrogen receptors; these figures were not significantly different from the corresponding incidence of 82% and 26%, respectively, among the initially excised tumors. However, the mean concentration of progesterone receptors in the recurrent tumor group was significantly higher when compared to the concentration in the initially excised group (p < 0.02).

Twenty meningiomas (39%) were considered to be radiation-induced, since they were removed from patients who had received scalp irradiation during childhood. The incidence and concentration of receptors in the radiation-induced tumors were generally comparable to those in the spontaneous meningiomas.

This study confirms previous reports of a high incidence of hormone receptors, mainly for progesterone, in meningiomas. In addition, it shows that in recurrent meningiomas these receptors persist and even increase. The results therefore support hormone treatment for nonresectable meningiomas, especially at recurrence.
Posterolateral approach to intradural extramedullary thoracic tumors
Authors: Steck John C. , Dietze Donald D. , Fessler Richard G.
Published: May 2009

✓ Six ventrally located intradural thoracic tumors were successfully resected through the posterolateral approach. This approach allows direct visualization of the ventral and dorsal boundaries of the tumor with minimal manipulation of the spinal cord. Compared to the traditional laminectomy, the operative time is increased but visualization of the tumor and spinal cord is markedly improved. Compared to the transthoracic approach, the posterolateral approach has fewer potential complications and eliminates the necessity of vertebrectomy. Neurological improvement occurred in all six patients. It is believed that this approach offers significant advantages for the treatment of ventrally located intradural thoracic tumors, and should be considered an alternative to the transthoracic approach.
Fractures of the C-2 vertebral body
Authors: Benzel Edward C. , Hart Blaine L. , Ball Perry A. , Baldwin Nevan G. , Orrison William W. , Espinosa Mary
Published: May 2009

✓ Vertical C-2 body fractures are presented in 15 patients with clinical and imaging correlations that suggest the existence of a variety of mechanisms of injury. In these patients, clinical and imaging correlations were derived by: 1) defining the point of impact by clinical examination; 2) defining the point of impact by soft-tissue changes on cranial magnetic resonance (MR) imaging or computerized tomography (CT); 3) obtaining an accurate history of the mechanism of injury; and 4) spine imaging (x-ray studies, CT, and MR imaging) of the C-2 body fracture and surrounding bone and soft tissue.

The cases presented involve the region located between the dens and the pars interarticularis of the axis. Although these fractures are rarely reported, they are not uncommon. An elucidation of their pathological anatomy helps to further the understanding of the mechanistic etiology of upper cervical spine trauma.

A spectrum of mechanisms of injury causing upper cervical spine fractures was observed. The type of injury incurred is determined predominantly by the force vector applied during impact and the intrinsic strength and anatomy of C-2 and its surrounding spinal elements. From this clinical experience, two types of vertical C-2 body fractures are defined and presented: coronally oriented (Type 1) and sagittally oriented (Type 2). A third type of C-2 body fracture, the horizontal rostral C-2 fracture (Type 3), is added for completeness; this Type 3 fracture is the previously described Type III odontoid process fracture described by Anderson and D'Alonzo.
Intradural perimedullary arteriovenous fistulas (Type IV spinal cord arteriovenous malformations)
Authors: Barrow Daniel L. , Colohan Austin R. T. , Dawson Robert
Published: May 2009

✓ Intradural perimedullary arteriovenous fistulas (Type IV spinal cord arteriovenous malformations (AVM's)) are rarely reported in the literature and occasionally are classified together with Type II AVM's as intradural spinal cord AVM's. The authors report eight cases of Type IV spinal cord AVM's managed over a 2-year period. Seven of these AVM's were surgically obliterated, with intraoperative angiography being used as an adjunct; one other patient was managed using endovascular therapy. One of these lesions was definitely and another possibly the result of trauma; a malformation in a newborn infant was clearly congenital. The authors believe that the pathophysiological mechanisms and anatomical features of these lesions represent a unique spinal vascular anomaly that must be recognized angiographically to plan appropriate therapy.
The role of hemolysate in the facilitation of oxyhemoglobin-induced contraction in rabbit basilar arteries
Authors: Aoki Toshiki , Takenaka Katsunobu , Suzuki Satoshi , Kassell Neal F. , Sagher Oren , Lee Kevin S.
Published: May 2009

✓ The importance of factors within hemolysate in modulating oxyhemoglobin (oxyHb)-induced contraction was examined in an in vitro model of rabbit basilar arteries. When the basilar arteries were exposed to purified oxyHb alone, the contractile response observed was significantly weaker than that seen in arteries exposed to hemolysate containing an equal concentration of oxyHb. In order to delineate the nature of the factors within hemolysate that facilitate contraction, hemolysate was fractionated, and various components were tested individually for their ability to elicit this effect. A low-molecular-weight fraction of hemolysate, ranging from 0.5 to 2.0 kD, elicited only a mild contraction. However, when this fraction was combined with purified oxyHb, the contractile response was comparable in magnitude to that of unfractionated hemolysate. These studies confirm that purified oxyHb is capable of inducing contraction in vitro. The data also demonstrate that oxyHb elicits a significantly weaker contraction than does hemolysate. In addition, the results suggest that low-molecular-weight components in hemolysate (in the 0.5- to 2.0-kD range), while incapable of inducing a potent contraction alone, may act in concert with oxyHb to elicit the vasoconstriction seen following subarachnoid hemorrhage.
Traumatic brain injury enhances the amnesic effect of an NMDA antagonist in rats
Authors: Hamm Robert J. , Pike Brian R. , O'Dell Dianne M. , Lyeth Bruce G.
Published: May 2009

✓ The authors have examined the effect of experimental traumatic brain injury on the amnesia produced by the N-methyl-D-aspartate (NMDA) antagonist MK-801. Rats were either subjected to a moderate level of fluid-percussion injury or prepared for injury but not injured (“sham injury”). Nine days following injury or sham injury, the rats were injected either with saline (sham/saline group, nine rats; injured/saline group, nine rats) or with 0.1 mg/kg of MK-801 (sham/MK-801 group, nine rats; injured/MK-801 group, eight rats) 30 minutes before being trained on a passive-avoidance task. Twenty-four hours later, the rats were tested for retention of the passive-avoidance task. Results revealed that the low dose of MK-801 did not significantly affect retention of the passive-avoidance task in the sham-injured group. In injured animals, administration of MK-801 produced a profound amnesia in contrast to the sham-injured animals treated with MK-801 and the injured animals treated with saline. To further investigate this enhanced sensitivity to the amnesic effects of MK-801 exhibited by the injured animals, nine injured and eight sham-injured rats were injected with 0.3 mg/kg of MK-801 15 minutes before injury. Results indicated that the animals treated with MK-801 before injury did not significantly differ from the sham-injured animals in retention of the passive-avoidance task. In addition, test results in the animals treated with MK-801 before injury and reinjected with MK-801 before passive-avoidance testing did not differ from those in untreated injured animals reinjected with saline before passive-avoidance testing. These findings indicate that MK-801 treatment before injury prevented the enhanced sensitivity to MK-801-induced amnesia that follows traumatic brain injury.
Central neurocytomas of the cervical spinal cord
Authors: Tatter Stephen B. , Borges Lawrence F. , Louis David N.
Published: May 2009

✓ Central neurocytoma is a neuronal neoplasm that occurs supratentorially in the lateral or third ventricles. The authors report the clinical, neuroradiological, and neuropathological features of two neurocytomas arising in the spinal cord of two men, aged 65 and 49 years. The patients presented with progressive neurological deficits referable to the cervical spinal cord. Magnetic resonance imaging revealed isodense intramedullary spinal cord tumors at the C3–4 level. Both tumors were initially misdiagnosed as gliomas. In Case 1 the correct diagnosis was made after electron microscopy revealed neuronal features. Immunostaining in Case 2 revealed that tumor cells were positive for synaptophysin and negative for glial fibrillary acidic protein, strongly indicating a neuronal tumor. It is suggested that this spinal cord neoplasm be included under the designation “central neurocytoma.”
Effects of vertebral axial decompression on intradiscal pressure
Authors: Ramos Gustavo , Martin William
Published: May 2009

✓ The object of this study was to examine the effect of vertebral axial decompression on pressure in the nucleus pulposus of lumbar discs. Intradiscal pressure measurement was performed by connecting a cannula inserted into the patient's L4-5 disc space to a pressure transducer. The patient was placed in a prone position on a VAX-D therapeutic table and the tensionometer on the table was attached via a pelvic harness. Changes in intradiscal pressure were recorded at resting state and while controlled tension was applied by the equipment to the pelvic harness. Intradiscal pressure demonstrated an inverse relationship to the tension applied. Tension in the upper range was observed to decompress the nucleus pulposus significantly, to below −100 mm Hg.
The validity of electrophysiological criteria used in selective functional posterior rhizotomy for treatment of spastic cerebral palsy
Authors: Steinbok Paul , Keyes Robert , Langill Lisa , Cochrane D. Douglas
Published: May 2009

✓ Although selective functional posterior rhizotomy (SFPR) is an established procedure for the treatment of spasticity, the electrophysiological criteria used to define which posterior rootlets should be cut have not been standardized. The purpose of this study was to determine the validity of the intraoperative electrophysiological criteria used to select posterior rootlets for sectioning in SFPR.

Intraoperative stimulation of posterior lumbosacral nerve roots and rootlets, using a 50-Hz stimulus at threshold intensity, was performed in five nonspastic children (controls) undergoing laminectomy for spinal cord untethering and in 32 spastic patients undergoing SFPR. Electromyographic responses were recorded in the upper and lower limbs, the neck, and the face. The pattern of sustained responses was assessed in detail in 17 additional patients who had previously undergone SFPR and in the five controls. Sustained responses with ipsilateral lower limb extrasegmental spread occurred in both spastic patients and the control group. Contralateral lower limb spread and suprasegmental spread to the upper limbs, neck, and face were found only in spastic children. Sustained responses with an incremental pattern were restricted to the spastic population and correlated well with the extent of contralateral and suprasegmental spread, whereas decremental patterns were not associated with contralateral spread.

It is concluded that contralateral and suprasegmental spread into the upper limbs, neck, and face, and incremental responses are probably valid criteria of abnormality.
Neural sheath tumors of major nerves
Authors: Donner Thomas R. , Voorhies Rand M. , Kline David G.
Published: May 2009

✓ Over a 22-year period, operations were performed on 263 patients for 288 primary benign tumors of major peripheral nerves. The tumors included 85 schwannomas, 197 neurofibromas, and six plexiform neurofibromas. Total removal was achieved in 83 of the 85 schwannomas, and 76 of these patients were available for follow-up evaluation. Motor function either improved or was unchanged in 87% of these patients and 85% of those with pain in the distribution of the involved nerve had either total or partial resolution of their symptoms. Of the neurofibromas, 123 occurred in 121 patients without von Recklinghausen's disease. All tumors within this group were completely excised using a fascicular approach to the tumor. Of the 99 patients available for follow-up evaluation, 90% had either improved or unchanged motor function and 88% had partial or complete resolution of pain syndromes. Fifty-nine patients with von Recklinghausen's disease had 80 tumors removed: 74 fusiform tumors (58 of which were completely removed) and six plexiform tumors. Forty-eight of the 58 patients with gross total removal of fusiform tumors were available for follow-up evaluation, of whom 83% had improved or unchanged motor function and 74% had partial or complete resolution of pain syndromes. All six patients with plexiform tumors had progression of symptoms postoperatively. One brachial plexus schwannoma recurred and was re-excised without subsequent recurrence at the 5-year follow-up evaluation. Several incompletely excised plexiform neurofibromas have recurred with a symptomatic presentation.
Plasminogen activator inhibitor-1 in the pathogenesis of delayed radiation damage in rat spinal cord in vivo
Authors: Sawaya Raymond , Rayford Alan , Kono Shinji , Ang K. Kian , Feng Yan , Stephens L. Clifton , Rao Jasti S.
Published: May 2009

✓ The pathophysiology of radiation-induced damage to the central nervous system (CNS) is poorly understood. Preliminary data suggest that fibrinolytic inhibitors are involved in the development of necrosis. In this study, cervical spinal cord irradiation was studied in 90 rats by measuring plasminogen activator inhibitor (PAI)-1 on Days 2, 7, 30, 60, 90, 120, 130, or 145 after irradiation. Paralysis due to radiation necrosis developed in all animals kept alive for 140 to 150 days. Assay of PAI-1 was by Western blot, enzyme-linked immunosorbent assay (ELISA), and complex formation with 125I-labeled urokinase. No PAI-1 was detected in normal spinal cord tissue or in irradiated spinal cord up to Day 90. However, PAI-1 was detected at Day 120 and was marked by elevated ELISA levels at the time of paralysis. Western blot showed detectable PAI-1 (51 kD) at Day 120 and very significant levels at the time of paralysis. Complex formation with 125I-labeled urokinase was also detected at Day 120 with similar results. Immunohistochemical studies showed that PAI-1 was highly concentrated within and immediately adjacent to zones of necrosis at 145 days and was absent in normal tissue. This study adds considerable weight to the proposal that PAI-1 is closely associated with the pathogenesis of CNS radiation necrosis.
Effect of tyrphostin on cell growth and tyrosine kinase activity of epidermal growth factor receptor in human gliomas
Authors: Miyaji Katsuya , Tani Eiichi , Shindo Hideki , Nakano Atsuhisa , Tokunaga Takashi
Published: May 2009

✓ The effects of tyrphostin, a selective protein tyrosine kinase inhibitor, on epidermal growth factor (EGF)-stimulated cell growth and EGF-receptor tyrosine kinase activity were studied in four human glioma cell lines. Stimulation by EGF induced variable enhancements of cell growth as well as tyrosine phosphorylation of EGF receptor and intracellular target proteins in all glioma cell lines. The level of immunoreactive EGF receptor detected with antibodies against extra- and intracellular domains was moderate in all four glioma cell lines, but markedly decreased with the latter antibody in two glioma cell lines. This variation was associated with considerable reduction of the EGF-stimulated tyrosine autophosphorylation level. Tyrphostin inhibited dose-dependently the EGF-stimulated cell growth and tyrosine autophosphorylation in all glioma cell lines, and the optimum time for the maximum inhibitory effect on tyrosine autophosphorylation was 12 to 18 hours after treatment with tyrphostin. The antiproliferative activity of tyrphostin nearly correlated quantitatively with its potency as an inhibitor of the EGF-stimulated EGF receptor tyrosine kinase activity. Tyrphostin had no significant effect on the immunoreactive EGF receptor levels, on the affinity constants and numbers of EGF receptor, or on the down-regulation and specific internalization of EGF receptor in any glioma cell line, suggesting that the effects of tyrphostin are not likely to be the results of reduction in EGF receptor and EGF binding capacity. In addition, the serum-stimulated cell growth was also inhibited dose-dependently by higher concentrations of tyrphostin in all glioma cell lines. It might be suggested, therefore, that tyrphostin inhibits EGF-stimulated cell growth by a specific suppression of EGF receptor tyrosine kinase activity, and at higher concentrations there appears to be some degree of either nonspecific inhibition or inhibition of serum-stimulated protein tyrosine kinase activity to induce the cell growth inhibition of gliomas.
Hemorrhage into a lumbar synovial cyst causing an acute cauda equina syndrome
Authors: Tatter Stephen B. , Cosgrove G. Rees
Published: May 2009

✓ Juxtafacet cysts of the lumbar spine have been reported with increasing frequency but their pathogenesis remains obscure. These cysts most frequently present with back pain, followed by chronic progressive radiculopathy or gradual onset of symptoms of spinal canal compromise. The authors report an unusual case of hemorrhage into a right L3–4 synovial cyst causing an acute cauda equina syndrome and describe its successful surgical treatment. The clinical, radiographic, and pathological features are discussed.
Progression of multiple cryptic vascular malformations associated with anomalous venous drainage
Authors: Ciricillo Samuel F. , Dillon William P. , Fink Matthew E. , Edwards Michael S. B.
Published: May 2009

✓ The case of a young girl with a pericallosal venous malformation associated with multiple cryptic vascular malformations (CVM's) is described. The presenting cryptic malformation, which hemorrhaged, was completely excised, but the venous malformation was not. Routine follow-up magnetic resonance images obtained over the past 9 years have documented the development of multiple new cryptic malformations along the radicles of the venous malformation. Magnetic resonance imaging and cerebral angiography revealed venous outflow obstruction at the junction of the venous malformation with the straight sinus. The association of CVM's with anomalous venous drainage patterns and the role of venous hypertension in the pathogenesis of cryptic malformations are discussed. This case suggests that CVM's associated with a venous malformation may recur and new ones may develop if the venous malformation is not excised, particularly if venous hypertension is also present. The likelihood of a surgical cure in these patients may depend on complete excision of both anomalies, which is rarely feasible because of the potentially devastating results of resecting a venous malformation. Alternative treatments for patients with both types of lesions are discussed.