bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal bone neoplasms: a report on 20 surgically treated cases
Authors: Sekhar Laligam N. , Pomeranz Shlomo , Janecka Ivo P. , Hirsch Barry , Ramasastry Sai
Published: May 2009

✓ The surgical resection of neoplasms involving the petrous bone and surrounding areas in 20 patients is reported. Technical advances described include the total resection of several tumors previously considered inoperable due to involvement of dura and brain, petrous internal carotid artery (ICA), the vein of Labbé, and adjacent areas such as the clivus and the cavernous sinus. Areas of reconstruction after resection included the ICA, the seventh and 11th cranial nerves, and the cranial base, often requiring the use of vascularized flaps. There were no intraoperative deaths. Many patients experienced significant temporary morbidity related primarily to wound healing and to lower cranial nerve palsy; however, all but three patients (all with fast-growing malignancies) returned to their preoperative functional status.

During a median follow-up period of 30 months (range 17 to 63 months), the 10 patients with benign tumors and slow-growing malignancies fared well, seven being alive and disease-free. The 10 patients with fast-growing malignancies fared poorly, only two being alive without disease. This outcome appeared to be related to tumor pathology and extent of invasion; both survivors harbored tumors confined to the petrous bone. An anatomical classification system of tumor spread is introduced, which should be considered concomitantly with tumor pathology.
The combined supra- and infratentorial approach for lesions of the petrous and clival regions; experience with 46 cases
Authors: Spetzler Robert F. , Daspit C. Phillip , Pappas Conrad T. E.
Published: May 2009

✓ The combined supra- and infratentorial approach has been subdivided into three variations: the retrolabyrinthine technique (petrous bone resection with preservation of hearing); the translabyrinthine technique (greater petrous bone resection and sacrifice of hearing); and the transcochlear technique (maximum petrous drilling, sacrifice of hearing, and transposition of the facial nerve). These three variations maximize temporal bone drilling and therefore provide exquisite exposure of the clivus and petrous regions with minimal or no brain retraction. The superior petrosal sinus is always sacrificed and the tentorium completely cut. The sigmoid sinus can be transected or kept intact, depending on the venous drainage and the degree of exposure required. A series of 46 patients who underwent the combined approach is presented.
Etiological evaluation of dural arteriovenous malformations of the lateral and sigmoid sinuses based on histopathological examinations
Authors: Nishijima Michiharu , Takaku Akira , Endo Shunro , Kuwayama Naoya , Koizumi Fumitomo , Sato Hideji , Owada Kenji
Published: May 2009

✓ Controversy persists concerning the pathogenesis of dural arteriovenous malformations (AVM's) and whether they are congenital or acquired. Furthermore, it remains undetermined whether the lesion is located in the sinus itself or within the sinus wall. In order to elucidate the pathogenesis of dural AVM's of the lateral and sigmoid sinuses, histopathological profiles of this disease were studied in serial sections of completely resected lesions from three patients. The essential lesion was histologically confirmed to be a dural arteriovenous fistula within the wall of the venous sinuses. The etiology process of this disease and its progression were evaluated.
Cranial and sacral dural arteriovenous fistulas as a cause of myelopathy
Authors: Partington Michael D. , Rüfenacht Daniel A. , Marsh W. Richard , Piepgras David G.
Published: May 2009

✓ The authors report a series of seven patients with myelopathy who were found to have spinal dural arteriovenous (AV) fistulas in which the nidus was located at some distance from the spinal cord. The nidus was intracranial in three cases and involved a sacral nerve root sheath in the other four, in each case, the arterialized draining vein led into the coronal plexus of medullary veins. A lack of normal draining radicular veins was noted in all cases. Magnetic resonance images were obtained in four patients and demonstrated spinal cord tissue changes only in the lower thoracic cord in three cases and in the cervical cord in one, all consistent with an ischemic process secondary to venous hypertension. Five patients were managed surgically by division of the draining vein, with improvement of the neurological deficit in all. One patient was treated by embolization alone and had stabilization of her deficit. The remaining patient in the series died of unrelated systemic disease before the spinal dural AV fistula could be treated.

These cases support the theory that venous hypertension is the dominant pathophysiological mechanism involved in spinal dural AV fistulas independent of their location. In patients with a suspected spinal dural AV fistula, lumbar and thoracic spinal angiography will reveal the site of the fistula in the majority of cases (88% in this series). In the remaining patients, the possibility of a remote fistula must be considered. The lack of normal venous drainage of the cord following injection in the artery of Adamkiewicz is the most reliable indicator of venous hypertension in the cord and can be helpful in making the decision to proceed with a search for a cranial or sacral arterial supply.
Direct evidence for a key role of protein kinase C in the development of vasospasm after subarachnoid hemorrhage
Authors: Nishizawa Shigeru , Nezu Nobukazu , Uemura Kenichi
Published: May 2009

✓ Vascular contraction is induced by the activation of intracellular contractile proteins mediated through signal transduction from the outside to the inside of cells. Protein kinase C plays a crucial role in this signal transduction. It is hypothesized that protein kinase C plays a causative part in the development of vasospasm after subarachnoid hemorrhage (SAH). To verify this directly, the authors measured protein kinase C activity in canine basilar arteries in an SAH model with (γ-32P)adenosine triphosphate and the data were compared to those in a control group. Protein kinase C is translocated to the membrane from the cytosol when it is activated, and the translocation is an index of the activation; thus, protein kinase C activity was measured both in the cytosol and in the membrane fractions.

Protein kinase C activity in the membrane in the SAH model was remarkably enhanced compared to that in the control group. The percentage of membrane activity to the total was also significantly greater in the SAH vessels than in the control group, and the percentage of cytosol activity in the SAH group was decreased compared to that in the control arteries. The results indicate that protein kinase C in the vascular smooth muscle was translocated to the membrane from the cytosol and was activated when SAH occurred. It is concluded that this is direct evidence for a key role of protein kinase C in the development of vasospasm.
The intracerebral distribution of BCNU delivered by surgically implanted biodegradable polymers
Authors: Grossman Stuart A. , Reinhard Carla , Colvin O. Michael , Chasin Mark , Brundrett Robert , Tamargo Rafael J. , Brem Henry
Published: May 2009

✓ The local concentration and distribution of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) within normal brain tissue were studied following surgical implantation of biodegradable polymer containing BCNU in New Zealand White rabbits. Cylindrical discs of poly(bis(p-carboxyphenoxy)-propane:sebacic acid) copolymer in a 20:80 formulation were made containing [3H]-inulin or [3H]-BCNU labeled in the methylene hydrogens of the chloroethyl groups. These were implanted in the brains of 56 New Zealand White rabbits. The animals were sacrificed 3, 7, 14, or 21 days later and the brains were rapidly removed, frozen, and prepared for quantitative autoradiography. Autoradiographs from coronal sections bisecting the polymer were analyzed to determine both the proportion of the brain section exposed to the tracer and the local drug concentrations as a function of distance from the polymer. Tritiated BCNU was also injected directly into the brains of eight additional rabbits, and local brain concentrations were studied over time.

The results of this study demonstrate that approximately 50% of the area of the brain sections was exposed to radiolabeled compound 3 days after BCNU-polymer implantation, 15% at 7 days, and less than 10% at 14 and 21 days. Polymer discs containing 600 µg BCNU generated 6 mM concentrations of BCNU in brain tissue 10 mm from the polymer at 3 and 7 days. Pharmacological studies demonstrated that approximately 25% of the tritium label was associated with intact BCNU 3 days following polymer implantation. Radiolabeled inulin delivered by polymer remained dispersed throughout the ipsilateral hemisphere for 14 days. Direct injection of [3H]-BCNU into brain parenchyma resulted in widely distributed tracer at 1 and 3 hours with rapid disappearance thereafter. It is concluded that local delivery of BCNU to brain tissue with this polymeric drug delivery system results in sustained high local concentrations of BCNU which may be of value in the treatment of patients with brain tumors.
Action of phospholipases A2 and C on free fatty acid release during complete ischemia in rat neocortex
Authors: Umemura Atsushi , Mabe Hideo , Nagai Hajime , sugino Fumihiko
Published: May 2009

✓ The levels of brain free fatty acids rapidly increase after the onset of ischemia. The purpose of this study was to investigate the action of phospholipases A2 and C during complete ischemia based on the effects of a phospholipase C inhibitor (phenylmethylsulfonyl fluoride) and the N-methyl-D-aspartate antagonist MK-801 on the release of free fatty acids in rat neocortex. Complete brain ischemia was induced in rats with cardiac arrest by intracardiac injection of KC1. Free fatty acid levels in the neocortex were measured 0, 2, 4, and 8 minutes after cardiac arrest. Phenylmethylsulfonyl fluoride inhibited the release of free fatty acids primarily from phosphatidylinositol during the first 2 minutes of ischemia and from phosphatidylcholine and phosphatidylethanolamine at 4 to 8 minutes of ischemia. Conversely, MK-801 inhibited free fatty acid release mainly from phosphatidylcholine and phosphatidylethanolamine at 2 to 4 minutes of ischemia.

These results indicate that the release of free fatty acids during the first 2 minutes of ischemia can be attributed mostly to the action of phospholipase C, and that the activation of phospholipase C further influences the activation of phospholipase A2 in the subsequent course, while phospholipase A2 predominantly acts after 2 minutes of ischemia.
The effect of tumor necrosis factor-α on human malignant glial cells
Authors: Del Maestro Rolando F. , Lopez-Torres Monica , McDonald Warren B. , Stroude Eric C. , Vaithilingam Indrasen S.
Published: May 2009

✓ The influence of human recombinant tumor necrosis factor-α has been assessed on a cell line (U-251) derived from a human malignant glial tumor. The results of this study demonstrate that tumor necrosis factor-α at doses of 50 and 100 ng/ml: 1) did not have cytotoxic or cytostatic effects on the U-251 cell line; 2) significantly increased the intracellular activity of manganese superoxide dismutase but had no effect on copper and zinc superoxide dismutase, catalase, or glutathione peroxidase activity; and 3) did not significantly alter the intracellular or extracellular general protease and collagenase type IV activity of these cells. The resistance of the U-251 cell line to tumor necrosis factor-α cytotoxicity may be related in part to the high intrinsic manganese superoxide dismutase activity present in this cell line combined with the ability of this cell line to induce substantial amounts of protective manganese superoxide dismutase activity in response to tumor necrosis factor-α.
Human antiglioma monoclonal antibodies from patients with astrocytic tumors
Authors: Dan Michael D. , Schlachta Christopher M. , Guy John , McKenzie Richard G. , Dorscheid Delbert R. , Sandor Victor A. , Villemure Jean-Guy , Price Gerald B.
Published: May 2009

✓ The current management of malignant gliomas is unsatisfactory compared to that of other solid tumors; the expected median survival period is less than 1 year with the patient undergoing conventional surgery, radiotherapy, and chemotherapy treatment. Immunological reagents could be a useful adjunct. Human monoclonal antibodies derived from patients with astrocytic tumors might recognize subtle antigenic specificities that would differ from those recognized by xenogeneic (murine) systems. Five hybridomas, designated as BT27/1A2, BT27/2A3, BT32/A6, BT34/A5, and BT54/B8, were produced from the fusion of peripheral blood lymphocytes of four patients with astrocytic tumors to the human myeloma-like cell line TM-H2-SP2. This cell line has a 46, XX karotype and is negative for hypoxanthine guanine phosphoribosyltransferase. All five human monoclonal antibodies produced 2.4 to 44 µg/ml of immunoglobulin M, had a similar but not identical pattern of reactivity against a panel of human tumor cell lines, and failed to react with normal human astrocytes. Labeling of four neuroectodermal tumor explant cultures by BT27/2A3 was demonstrated by flow cytometry. Karyotyping of three of the five hybridomas demonstrated that two were pseudodiploid (2–3n) and one hypodiploid (< 2n). The monoclonality of the hybridomas was evaluated by Southern blot analysis of JH gene rearrangements, revealing two types of rearrangements for each hybridoma, both consistent with monoclonality. Preliminary antigen characterization indicated that at least four of the five human monoclonal antibodies were directed to cell-surface glycolipids.
The effects of lumbar sympathectomy on regional spinal cord blood flow in rats during acute hemorrhagic hypotension
Authors: Iwai Atsushi , Monafo William W.
Published: May 2009

✓ It has not previously been determined whether the sympathetic nervous system has a role in the regulation of regional blood flow in the spinal cord. The authors used 14C-butanol distribution to measure regional spinal cord blood flow at seven cord levels, in the sciatic nerve, and in the biceps femoris muscle in 36 rats, 18 of which had undergone excision of both lumbar sympathetic chains at least 6 days previously. Blood flows were measured during pentobarbital anesthesia. Mean arterial blood pressure (MABP) was monitored and arterial pO2, pCO2, and pH were determined prior to flow measurement. Anesthetic dose and duration were controlled. Measurements were made in normotensive rats and in rats with MABP maintained at either 69 ± 3 mm Hg or 48 ± 3 mm Hg for 1 hour by the withdrawal of arterial blood. One-half of the rats in each group had undergone sympathectomy. The resting cord blood flow was lower than control values following sympathectomy only at the S1–4 cord level (p < 0.01) and cauda equina (p < 0.01), and was marginally lower at the L1-2 and L3–6 levels (p < 0.1). Cord blood flow was unaffected by sympathectomy during moderate hypotension. During severe hypotension, cord blood flow was less than control at the C3–5 level (p < 0.05), but did not differ from control at the other six levels. Flows in nerve and muscle were consistent with known effects of sympathectomy on peripheral tissues. It is concluded that, at most, sympathectomy may moderately decrease resting blood flow in the cord levels caudal to L-1. Sympathectomy has no major effect on regional spinal cord blood flow in rats stressed by either moderate or severe arterial hemorrhage.
Primary intracranial Hodgkin's lymphoma without dural attachment
Authors: Clark W. Craig , Callihan Thomas , Schwartzberg Lee , Fontanesi James
Published: May 2009

✓ A very rare case of primary intracranial Hodgkin's lymphoma without dural attachment is reported. Based on a review of the literature and the clinical results in the present case, recommended therapy consists of surgical excision whenever possible, followed by radiotherapy.
Tortuous peripheral arteries: a cause of focal neuropathy
Authors: Segal Ricardo , Machiraju Usha , Larkins Mark
Published: May 2009

✓ Segmental ulnar neuropathy has been reported as a result of ulnar nerve compression due to posttraumatic false aneurysms of the ulnar artery and, more infrequently, due to thrombosis or true aneurysms of the same vessel. The authors present a case of segmental sensory ulnar neuropathy in the wrist which intraoperatively demonstrated impingement on the ulnar nerve by a tortuous ulnar artery. The symptomatic relief and electrophysiological improvement that occurred immediately following neurovascular decompression confirm that the vascular anomaly was the cause of neuropathy. Pulsatile pressure applied to the nerve trunk may have triggered ectopic stimulation of sensory fibers manifested by a tingling and burning sensation. There was immediate resolution of paresthesia following mobilization of the impinging vessel from the nerve. Subsequent rapid electrophysiological recovery may be explained by improvement in focal nerve microcirculation following vascular decompression. Tortuosity (megadolichoectatic anomaly) of intracranial arteries has been related to cranial nerve or brain-stem dysfunction; however, this appears to be the first report in the literature of a case in which such association has been found to occur extracranially, involving a peripheral nerve.
Meningeal melanocytoma: magnetic resonance imaging characteristics and pathological features
Authors: Uematsu Yuji , Yukawa Syuuya , Yokote Hideki , Itakura Toru , Hayashi Seiji , Komai Norihiko
Published: May 2009

✓ A case of meningeal melanocytoma at the foramen magnum is reported in a 62-year-old man. Magnetic resonance (MR) imaging revealed characteristic signal patterns: homogeneous high intensity on the T1-weighted image and low intensity on the T2-weighted image. Light microscopy showed a histological appearance similar to that of melanotic meningioma. The ultrastructural features of the neoplastic cells were compatible with those of melanocytes, but they contained no features of arachnoidal cells. Immunohistochemical bromode-oxyuridine study revealed low proliferative activity among the neoplastic cells. The MR appearance and pathological features in this rare case of meningeal melanocytoma are demonstrated and discussed.
Spontaneous intracerebral hematoma from occult carotid-cavernous fistula during pregnancy and puerperium
Authors: Lin Tzu-Kang , Chang Chen-Nen , Wai Yau-Yau
Published: May 2009

✓ In most cases, intracerebral hemorrhage during pregnancy or puerperium results from cerebral aneurysms or arteriovenous malformations. The authors present a case of a 30-year-old woman whose symptoms from a traumatic carotid-cavernous fistula had completely resolved 1½ years after the event, but recurred 4 years later, causing two hemorrhages during pregnancy (33rd and 35th week of gestation) and one during the postpartum period (10 days after Caesarean section). Partial thrombosis of the cavernous sinus with obliteration of most of the drainage from the fistula accounted for the resolution of clinical symptoms, but also promoted back-flow to the preserved drainage of superficial cortical veins. The hemodynamic changes and the hormonal effects due to the patient's subsequent pregnancy further aggravated the venous engorgement and finally caused rupture. All three hematomas occurred in the vicinity of the extremely dilated veins, suggesting that back-flow with venous hypertension was the probable cause for the intracerebral hematomas. Spontaneous healing of the carotid-cavernous fistula should be confirmed with cerebral angiography.
Overall outcome in aneurysmal subarachnoid hemorrhage
Authors: Säveland Hans , Hillman Jan , Brandt Lennart , Edner Göran , Jakobsson Karl-Erik , Algers Göran
Published: May 2009

✓ The present prospective study, with participation of five of the six neurosurgical centers in Sweden, was conducted to evaluate the overall management results in patients with aneurysmal subarachnoid hemorrhage (SAH). The participating centers covered 6.93 million (81%) of Sweden's 8.59 million inhabitants. All patients with verified aneurysmal SAH admitted between June 1, 1989, and May 31, 1990, were included in this prospective study. A uniform management protocol was adopted involving ultra-early referral, earliest possible surgery, and aggressive anti-ischemic treatment.

A total of 325 patients were admitted during the study period, 69% within 24 hours after hemorrhage. On admission, the patients were graded according to the scale of Hunt and Hess: 43 patients (13%) were classified in Grade I, 119 (37%) in Grade II, 53 (16%) in Grade III, 76 (23%) in Grade IV, and 34 (II%) in Grade V. Nimodipine was administered to 269 of the 325 patients: intravenously in 218, orally in 15, and intravenously followed by orally in 36. At follow-up examination 3 to 6 months after SAH, 183 patients (56%) were classified as having made a good neurological recovery, 73 patients (23%) suffered some morbidity, and 69 (21%) were dead. Surgery was performed in 276 (85%) of the patients; emergency surgery with evacuation of an associated intracerebral hematoma was carried out in 30 patients. Early surgery (within 72 hours after SAH) was performed in 170 individuals, intermediate surgery (between Days 4 and 6 post-SAH) in 29 patients, and late surgery (Day 7 or later after SAH) in 47 individuals. Of 145 patients with supratentorial aneurysms who were preoperatively in Hunt and Hess Grades I to III and who were treated within 72 hours, 81 made a good recovery; in 5.5% of patients, the unfavorable outcome was ascribed to delayed ischemia. It is concluded that, among patients with all clinical grades and aneurysmal locations, almost six of 10 SAH victims referred to a neurosurgical unit can be saved and can recover to a normal life.
Hippocampal pathology in patients with intractable seizures and temporal lobe masses
Authors: Fried Itzhak , Kim Jung H. , Spencer Dennis D.
Published: May 2009

✓ The authors examined hippocampal tissue removed during surgical procedures in 17 patients with intractable epilepsy who were found by preoperative magnetic resonance imaging or computerized tomography to have intra-axial masses in the temporal lobe. Neuronal densities in the cornu ammonis (CA) fields of the hippocampus and in the dentate granule cell layer were measured in hematoxylin and eosin-stained sections and were found to be lower compared to a group of 18 autopsy controls. The neuronal densities in all hippocampal fields except CA2 were related to the patient's age at seizure onset. Patients with an earlier onset of seizures had lower neuronal densities. With the exception of CA4, neuronal densities were not significantly related to the duration of the seizure disorder. Cell counts in all fields except CA2 were also related to the location of the lesion in the temporal lobe. Patients with mesial temporal lesions had lower neuronal counts. These results suggest increased vulnerability of hippocampal cytoarchitecture to proximal lesions with early ictal manifestation.
Neuro-ophthalmological function of patients with pineal region tumors approached transtentorially in the semisitting position
Authors: Nazzaro Jules M. , Shults William T. , Neuwelt Edward A.
Published: May 2009

✓ To optimize orientation and operative exposure for aggressive resection, the authors approached pineal region tumors transtentorially with the patient in a semisitting position. In the current report, 12 consecutive patients were evaluated to document operative ocular morbidity referable to the brain stem as well as visual deficits secondary to occipital lobe retraction. Before craniotomy, ophthalmological findings related to dorsal midbrain dysfunction were evident in four of the 10 patients who had previously undergone ventricular shunting. The other patients developed a partial or complete Parinaud's syndrome in the early postoperative period and some suffered additional deficits such as cranial nerve palsies. These deficits improved to varying degrees in all patients. Although each had full visual fields preoperatively, an absolute or incomplete left homonymous hemianopsia developed in the immediate postoperative period. Such visual field deficits fully resolved over a variable period of time in 10 of the 12 patients. One patient has a permanent left homonymous hemianopsia, while another has a left homonymous paracentral scotoma. Eight patients were able to return to preoperative pursuits. While ocular abnormalities related to dorsal midbrain dysfunction are most probably independent of operative approach, visual field deficits attributable to occipital lobe retraction were common in patients after a occipital transtentorial approach performed in the semisitting position. Reading difficulties associated with ocular motor dysfunction due to dorsal midbrain involvement represent the principal long-term neuro-ophthalmological complaint of patients who have undergone pineal region surgery.
Correlation of basic fibroblast growth factor expression levels with the degree of malignancy and vascularity in human gliomas
Authors: Takahashi Jun A. , Fukumoto Manabu , Igarashi Koichi , Oda Yoshifumi , Kikuchi Haruhiko , Hatanaka Masakazu
Published: May 2009

✓ Basic fibroblast growth factor (FGF) is a mitogen, a differentiation factor for neuroectoderm-derived cells, and a potent angiogenic factor. The authors have previously demonstrated that the messenger ribonucleic acid of basic FGF is expressed in more than 90% of human gliomas. In the present study, they examined the expression of basic FGF in human glioma tissues using immunohistochemical techniques with a mouse monoclonal antibody against human basic FGF. They also correlated the basic FGF level with the histological grades of malignancy assessed by the number of nucleolar organizer regions (NOR's). Basic FGF was detected in 18 of 19 gliomas, whereas it was undetectable in two normal brains. The expression level of basic FGF peptide increased proportionally with the degree of malignancy. There was also a tendency for the number of NOR's in glioma cells to increase in glioma samples with a high level of basic FGF expression. Furthermore, most of the cases with increased vascularity demonstrated on cerebral angiograms showed a relatively high level of basic FGF expression of tumor cells and a large number of NOR's in endothelial cells in tumor tissues. These results suggest that basic FGF is actually produced in most gliomas and is involved in tumorigenesis and malignant progression as an autocrine growth factor. Moreover, basic FGF may play an important role in tumor neovascularization as a paracrine angiogenic factor.
Biomechanics of sequential posterior lumbar surgical alterations
Authors: Cusick Joseph F. , Yoganandan Narayan , Pintar Frank A. , Reinartz John M.
Published: May 2009

✓ Compromise of the functional integrity of the posterior lumbar ligaments and facet joints is a common occurrence after repeated lumbar operative procedures. To evaluate the biomechanical effects of sequential surgical alterations, this investigation analyzed bilateral facetectomies (medial, total, and total with posterior ligament section) in three segments of human cadaveric lumbar spines under increasing compression-flexion. These iatrogenic alterations, designed to replicate common methods of surgical exposure, were created at the lower intervertebral joint (L4–5) while the upper joint (L3–4) remained intact. Overall strength characteristics in the physiological range of 400 N and 600 N demonstrated significant differences (p < 0.05) in applied compressions for all preparations compared to the intact specimen. Comparison of sequential surgeries, however, did not demonstrate this tendency. Significant changes in the movement of the spinous processes at the upper (unaltered) level occurred only after posterior ligament section, whereas the lower (altered) level showed markedly increasing distraction of both the facets and the spinous processes with sequential operations. Sectioning of the supraspinous/interspinous ligament and associated fascial attachments resulted in a marked transfer of motion to the altered level. This was manifested by the increased anterior displacement of the centrode at the lower level associated with probable posterior migration of the centrode at the upper level. These data suggest that the effects of progressive surgical alterations of the lumbar facet joints are controllable in a preparation undergoing acute compression-flexion loads until the supraspinous/interspinous ligaments, with associated residual tendinous, midline muscle, and fascial attachments, are violated.
The effect of chronic subarachnoid hemorrhage on basal endothelium-derived relaxing factor activity in intrathecal cerebral arteries
Authors: Edwards David H. , Byrne James V. , Griffith Tudor M.
Published: May 2009

✓ The authors have investigated the hypothesis that loss of endothelium-derived relaxing factor (EDRF) activity contributes to cerebral vasospasm after subarachnoid hemorrhage. Adventitial exposure to hemoglobin was studied angiographically by injecting purified hemoglobin solution or autologous whole blood into the cisterna magna of anesthetized pigs. Both interventions induced intra- but not extracerebral vasoconstriction, which persisted for 2 and 7 days, respectively. Cyclic guanosine monophosphate (cGMP) levels were measured in isolated buffer-perfused pig intrathecal arteries to quantify inhibition of basal EDRF activity by hemoglobin. Adventitial exposure was less effective than intimal exposure, 10 µM hemoglobin applied adventitially for 30 minutes having an effect equivalent to that of 1 µM applied intraluminally for 5 minutes. The depression of cGMP levels by hemoglobin was reversible and equivalent to the effect of endothelial denudation or incubation with NG-nitro-L-arginine methyl ester, so that the effects of hemoglobin can be attributed to a specific action on EDRF rather than interaction with a nitric oxide-like substance produced by vascular smooth muscle or adventitial nerves. Cyclic GMP levels in isolated arteries were unchanged after in vivo exposure to hemoglobin for either 2 or 7 days or to whole blood for 2 days, and were reduced by intraluminal perfusion with 1 µM hemoglobin. In contrast, after 7 days of in vivo exposure to whole blood, cGMP levels were already depressed, and not further reduced by intraluminal perfusion with 1 µM hemoglobin. The findings support the view that adventitially applied hemoglobin can inhibit basal EDRF activity and that in vivo adventitial exposure to whole blood leads to a reduction in basal cGMP levels in association with vasoconstriction of intrathecal arteries. Both mechanisms could contribute to the clinical syndrome of cerebral vasospasm after subarachnoid hemorrhage.
Anastomosis of the anterior temporal artery to a secondary trunk of the middle cerebral artery for treatment of a giant M1 segment aneurysm
Authors: Bederson Joshua B. , Spetzler Robert F.
Published: May 2009

✓ The clinical course, operative technique, and angiographic outcome are reported for a patient with a giant intracranial aneurysm of the proximal middle cerebral artery (MCA) who presented with symptoms of ischemia. Treatment of the aneurysm required bypassing the involved MCA bifurcation, but the patient lacked a suitable donor superficial temporal artery. The involved arterial segment was therefore bypassed with a side-to-side anastomosis of the anterior temporal artery to one of the secondary trunks of the MCA. This bypass eliminated the need to harvest a vein graft and re-established flow using in situ intracranial vessels of similar diameter, minimal arterial dissection, and only one suture line.
Fentanyl-induced electrocorticographic seizures in patients with complex partial epilepsy
Authors: Tempelhoff René , Modica Paul A. , Bernardo Kerry L. , Edwards Isaac
Published: May 2009

✓ Although electrical seizure activity in response to opioids such as fentanyl has been well described in animals, scalp electroencephalographic (EEG) recordings have failed to demonstrate epileptiform activity following narcotic administration in humans. The purpose of this study was to determine whether fentanyl is capable of evoking electrical seizure activity in patients with complex partial (temporal lobe) seizures. Nine patients were studied in whom recording electrode arrays had been placed in the bitemporal epidural space several days earlier to determine which temporal lobe gave rise to their seizures. The symptomatic temporal lobe was localized by correlating clinical and electrical seizure activity obtained during continuous simultaneous videotape and epidural EEG monitoring. In each patient, clinical seizures and electrical seizure activity were consistently demonstrated to arise unilaterally from one temporal lobe (four on the right, five on the left). During fentanyl induction of anesthesia in preparation for secondary craniotomy for anterior temporal lobectomy, eight of the nine patients exhibited electrical seizure activity at fentanyl doses ranging from 17.7 to 35.71 µg · kg−1(mean 25.75 µg · kg−1). More importantly, four of these eight seizures occurred initially in the “healthy” temporal lobe contralateral to the surgically resected lobe from which the clinical seizures had been shown to arise. These findings indicate that, in patients with complex partial seizures, moderate doses of fentanyl can evoke electrical seizure activity. The results of this study could have important implications for neurosurgical centers where electrocorticography is used during surgery for the purpose of determining the extent of the resection.
Changes in gamma-aminobutyric acid and somatostatin in epileptic cortex associated with low-grade gliomas
Authors: Haglund Michael M. , Berger Mitchel S. , Kunkel Dennis D. , Franck JoAnn E. , Ghatan Saadi , Ojemann George A.
Published: May 2009

✓ The role of specific neuronal populations in epileptic foci was studied by comparing epileptic and nonepileptic cortex removed from patients with low-grade gliomas. Epileptic and nearby (within 1 to 2 cm) nonepileptic temporal lobe neocortex was identified using electrocorticography. Cortical specimens taken from four patients identified as epileptic and nonepileptic were all void of tumor infiltration. Somatostatin- and γ-aminobutyric acid (GABAergic)-immunoreactive neurons were identified and counted. Although there was no significant difference in the overall cell count, the authors found a significant decrease in both somatostatin- and GABAergic-immunoreactive neurons (74% and 51 %, respectively) in the epileptic cortex compared to that in nonepileptic cortex from the same patient. It is suggested that these findings demonstrate changes in neuronal subpopulations that may account for the onset and propagation of epileptiform activity in patients with low-grade gliomas.
Arteriovenous malformations of the brain: choosing embolic materials to enhance safety and ease of excision
Authors: Purdy Phillip D. , Batjer H. Hunt , Risser Richard C. , Samson Duke
Published: May 2009

✓ The authors report their experience with surgical resection of 108 previously embolized arteriovenous malformations (AVM's). Embolization was performed via only transfemoral catheterization in 70 lesions and via the surgical exposure of feeding vessels in 32. The remaining six patients were referred for resection following silicone sphere embolization elsewhere. Materials used included polyvinyl alcohol (PVA) foam, platinum microcoils, detachable silicone balloons, surgical silk, a mixture of 33% ethanol and microfibrillar collagen, and isobutyl cyanoacrylate (IBCA). It is believed that proximal arterial occlusion with balloons is an inferior choice for preresection embolization, because the technical difficulty of placement is high and the nidus of the AVM is unaffected. Vascular coagulation and section and AVM retraction are more difficult with IBCA; therefore, this is also considered an inferior choice.

Among the materials studied, the combination of PVA for distal occlusion and microcoils for proximal occlusion appears to be the superior choice. Fewer complications (stroke or hemorrhage) are seen when intraarterial Amytal (amobarbital) testing is used to guide the embolization. Data regarding toxicity, oncogenicity, and vascular metabolism or recanalization associated with PVA, IBCA, and n-butyl cyanoacrylate are reviewed.
Symptomatic and functional outcome of stereotactic ventralis lateralis thalamotomy for intention tremor
Authors: Goldman Marc S. , Kelly Patrick J.
Published: May 2009

✓ In the past, intention tremor has responded well to selected neuroablative procedures; however, objective symptomatic and functional outcomes of ventralis lateralis (VL) thalamotomy specifically for intention tremor in the post-computerized tomography era has rarely been reported. This series explored the symptomatic and functional impact of VL thalamotomy on 14 patients presenting at the Mayo Clinic with severe, refractory intention tremor due to multiple sclerosis (five patients), trauma (four patients), or stroke (five patients).

General neurological examinations, psychometric evaluations, speech pathology assessments, and neuroradiological scans were performed. Pre- and postoperative disability were graded according to a modified form of an established rating scale for tremor. All patients received VL radiofrequency thalamotomies utilizing neurophysiological recording and stimulation control. Contralateral targeted upper-extremity tremor remained symptomatically absent or markedly reduced in 81.8% of cases (mean follow-up period 23.4 months). The median disability score was reduced by 12 points (0.02 < p < 0.05). Persistent surgical morbidity was limited to two patients with mild, nondisabling dysarthrias. One elderly patient died of pulmonary complications 2 weeks postoperatively. There were no reported surgically induced exacerbations in multiple sclerosis; however, some of these patients exhibited difficulties with electrophysiological localization. These results compare favorably with those reported in the literature and confirm that stereotactic VL thalamotomy for debilitating intention tremor carries a low surgical risk and can be an effective treatment option for properly selected patients.
Atretic cephalocele: the tip of the iceberg
Authors: Martinez-Lage Juan F. , Sola Joaquin , Casas Carlos , Poza M´ximo , Almagro Maria J. , Girona Diego G.
Published: May 2009

✓ Atretic cephalocele appears as an unimportant and benign lesion. This malformation consists of meningeal and vestigial tissues (arachnoid, glial, or central nervous system rests). The authors report the findings in 16 cases (seven parietal and nine occipital) of rudimentary cephaloceles. Twelve patients presented with associated brain abnormalities detected by either computerized tomography (CT) or magnetic resonance imaging (MR). Nine lesions also exhibited an anomalous vascular component demonstrated by CT or MR imaging or at surgery. The existence of this tiny malformation in five cases was the main diagnostic clue to a severe complex of cerebral anomalies, namely cerebro-oculomuscular (Walker-Warburg) syndrome. An occipital location of the atretic cephalocele was associated with the worst prognosis, with only two children developing normally. However, a parietal location carried a better prognosis, which is contrary to the outcome reported in the current literature.

The authors classify atretic cephaloceles into two types based on histological examination of the surgical specimens, and suggest that these types represent different stages in the development of this malformation. It is concluded that, in the evaluation of the atretic cephalocele, the neurosurgeon is obliged to proceed to a detailed neuroradiological study of the patient and that the prognosis does not depend on the existence of the cephalocele itself, but rather on associated “occult” brain anomalies.
Intrathecal baclofen for spasticity of spinal origin: seven years of experience
Authors: Penn Richard D.
Published: May 2009

✓ A total of 66 consecutive patients with severe spasticity of spinal cord origin were screened with intrathecal baclofen, and all but two responded with a two-point decrease in their Ashworth spasticity scale and/or spasm scale score. Of these, 62 elected to receive chronic intrathecal baclofen administration by means of an implanted delivery system. These patients have been followed for an average of 30 months (the first three for 81 months). Intrathecal baclofen has been well tolerated and all serious side effects were transient and have been managed by dose adjustments. The pump presently available has worked safely; the only problem has been stalling in 7% of these devices. The catheter system has had to be repaired in just over one-half of the patients and is the main cause of interruption of drug delivery. Of the 62 patients implanted, 52 (84%) continue to be treated adequately for spasticity; there are three poor long-term responders, four deaths due to underlying disease, and three whose participation has been voluntarily withdrawn. It is suggested that long-term control of spinal spasticity by intrathecal baclofen can be achieved in most patients.
Management of cervical spinal cord injury in ankylosing spondylitis: the intervertebral disc as a cause of cord compression
Authors: Rowed David W.
Published: May 2009

✓ Twenty-one patients with universal syndesmophytosis due to ankylosing spondylitis were identified in a consecutive series of 1578 patients with acute spine and spinal cord injuries. They were predominantly male, older than spinal cord-injured patients in general, and most were injured by falls. Approximately one-half were managed by halo-vest immobilization alone with good clinical and radiological outcomes. The remainder required surgery either for recurrent dislocation or for spinal cord compression associated with neurological deterioration. Extradural hematoma, a recognized cause of spinal cord compression in ankylosing spondylitis patients with spinal fractures, was encountered in two patients. Herniated intervertebral disc as a cause of spinal cord compression in ankylosing spondylitis does not appear to have been previously reported and was recognized three times in the present series, once in association with extradural hematoma. The pathology of ankylosing spondylitis is such that the nucleus pulposus tends to be spared, allowing disc herniation to occur in the heavily ossified spine. In virtually all patients, satisfactory correction of the flexion deformity could be safely accomplished following spinal fracture.

It is concluded that fracture/dislocations of the cervical spine should be managed initially by halo-vest immobilization, without prior traction and with careful incremental correction of flexion deformity. Decompression is performed as required for extradural hematoma or intervertebral disc herniation, and internal fixation is carried out for recurrent dislocation.
On spinal osteochondromas
Authors: Albrecht Steffen , Crutchfield J. Stewart , SeGall Gary K.
Published: May 2009

✓ Osteochondromas (or osteocartilaginous exostoses) make up about 30% to 40% of benign bone tumors. Most are solitary lesions but some are multiple, usually with autosomal dominant inheritance. From 1% to 4% of osteochondromas occur in the spine, where they can cause a variety of signs and symptoms, including those of spinal cord or spinal root compression. The authors present five patients with osteochondromas of the spine and review the findings together with those of over 130 cases reported since 1907. The cases were divided into: 1) spinal osteochondromas in patients with multiple osteochondromas, and 2) solitary osteochondromas occurring in the spine. The age (mean ± standard error of the mean) of patients in the first group was 21.6 ± 1.8 years compared to 30.0 ± 2.1 years for those in the second group (p < 0.02). There was a significant male predominance overall (M:F = 2.5:1; p < 0.0005). In both groups, one-half of the lesions involved the cervical spine. Symptoms are caused by pressure on adjacent structures. Spinal cord compression was reported more than twice as frequently in the multiple osteochondroma group as in the single osteochondroma group (77% vs 33%; p < 0.0005). Computerized tomography (CT) is the imaging procedure of choice. In both groups, the majority of surgically treated patients (90% and 88%, respectively) improve, with about three-quarters of the improved patients having no residual disease or only minor deficits.
Loss of cerebral regulation during cardiac output variations in focal cerebral ischemia
Authors: Tranmer Bruce I. , Keller Ted S. , Kindt Glenn W. , Archer David
Published: May 2009

✓ Focal cerebral ischemia was induced in anesthetized macaque monkeys by unilateral middle cerebral artery occlusion. The effect of blood volume expansion by a colloid agent and subsequent exsanguination to baseline cardiac output (CO) on local cerebral blood flow (CBF) was measured by the hydrogen clearance technique in both ischemic and nonischemic brain regions. Cardiac output was increased to maximum levels (159% ± 92%, mean ± standard error of the mean) by blood volume expansion with the colloid agent hetastarch, and was then reduced a similar amount (166% ± 82%) by exsanguination during the ischemic period. Local CBF in ischemic brain regions varied directly with CO, with a correlation coefficient of 0.89 (% change CBF/% change CO), while CBF in nonischemic brain was not affected by upward or downward manipulations of CO. The difference in these responses between ischemic and nonischemic brain was highly significant (p < 0.001).

The results of this study show a profound loss of regulatory control in ischemic brain in response to alterations in CO, thereby suggesting that blood volume variations may cause significant changes in the intensity of ischemia. It is proposed that CO monitoring and manipulation may be vital for optimum care of patients with acute cerebral ischemia.
Cytokines and immunoregulatory molecules in malignant glial neoplasms
Authors: Schneider John , Hofman Florence M. , Apuzzo Michael L. J. , Hinton David R.
Published: May 2009

✓ Cytokines are important regulatory proteins controlling growth and differentiation of normal and malignant glial cells. Astrocytes and microglial cells produce and respond to many of the same cytokines employed by cells of the immune system. The authors have analyzed 15 histologically confirmed malignant glial neoplasms for the presence of infiltrating lymphocytes, macrophages, cytokines, and other immunoregulatory molecules using a panel of specific monoclonal and polyclonal antibodies on frozen-tissue sections. All neoplasms showed focal T-cell infiltration with CD8 cells predominating. Infiltration of activated macrophages (positive for CD11c, class II, and interleukin-2 receptor) was marked in all tumors. Within the neoplasm, tumor necrosis factor-α (TNF-α)- and interleukin (IL)-6-positive macrophages were prominent in five cases, while the tumor cells themselves were only weakly positive. In the other 10 cases, the numerous infiltrating macrophages were only rarely immunoreactive for TNF-α or IL-6. Transforming growth factor-β (TGF-β) immunoreactivity was most prominent in those tumors with little TNF-α-positive macrophage infiltration, although intratumoral variability was present. This study suggests that, in malignant gliomas, the cytokines TNF-α and IL-6, although weakly present in neoplastic cells, are most prominent in infiltrating macrophages and in those regions of the tumors that show little immunoreactivity for TGF-β. The important interactions among neoplastic, reactive glial, and inflammatory cells, which regulate tumor growth, are likely to be in part mediated through these molecules.