bluuebunny/crossref_metadata_2025 huggingface dataset:
Review of the secondary injury theory of acute spinal cord trauma with emphasis on vascular mechanisms
Authors: Tator Charles H. , Fehlings Michael G.
Published: May 2009

✓ In patients with spinal cord injury, the primary or mechanical trauma seldom causes total transection, even though the functional loss may be complete. In addition, biochemical and pathological changes in the cord may worsen after injury. To explain these phenomena, the concept of the secondary injury has evolved for which numerous pathophysiological mechanisms have been postulated. This paper reviews the concept of secondary injury with special emphasis on vascular mechanisms. Evidence is presented to support the theory of secondary injury and the hypothesis that a key mechanism is posttraumatic ischemia with resultant infarction of the spinal cord. Evidence for the role of vascular mechanisms has been obtained from a variety of models of acute spinal cord injury in several species. Many different angiographic methods have been used for assessing microcirculation of the cord and for measuring spinal cord blood flow after trauma. With these techniques, the major systemic and local vascular effects of acute spinal cord injury have been identified and implicated in the etiology of secondary injury.

The systemic effects of acute spinal cord injury include hypotension and reduced cardiac output. The local effects include loss of autoregulation in the injured segment of the spinal cord and a marked reduction of the microcirculation in both gray and white matter, especially in hemorrhagic regions and in adjacent zones. The microcirculatory loss extends for a considerable distance proximal and distal to the site of injury. Many studies have shown a dose-dependent reduction of spinal cord blood flow varying with the severity of injury, and a reduction of spinal cord blood flow which worsens with time after injury. The functional deficits due to acute spinal cord injury have been measured electrophysiologically with techniques such as motor and somatosensory evoked potentials and have been found proportional to the degree of posttraumatic ischemia. The histological effects include early hemorrhagic necrosis leading to major infarction at the injury site.

These posttraumatic vascular effects can be treated. Systemic normotension can be restored with volume expansion or vasopressors, and spinal cord blood flow can be improved with dopamine, steroids, nimodipine, or volume expansion. The combination of nimodipine and volume expansion improves posttraumatic spinal cord blood flow and spinal cord function measured by evoked potentials. These results provide strong evidence that posttraumatic ischemia is an important secondary mechanism of injury, and that it can be counteracted.
Stereotactic craniotomy in the resection of small arteriovenous malformations
Authors: Sisti Michael B. , Solomon Robert A. , Stein Bennett M.
Published: May 2009

✓ Surgical resection of 10 obscure arteriovenous malformations (AVM's) was accomplished with craniotomy guided by computerized tomography (CT) or angiography and the use of the Brown-Roberts-Wells stereotactic frame. Stereotactic craniotomy was invaluable for resection of the following types of AVM's: 1) AVM's with a nidus less than 2 cm in diameter, 2) AVM's located in an eloquent area of the brain, and 3) AVM's located deep in the brain. Stereotactic localization of these AVM's on preoperative radiological studies provides a precise route to the nidus, often avoiding important areas of the brain. This series included six male and four female patients with a mean age of 32 years. All patients presented with an intracerebral hemorrhage, from which eight made a complete neurological recovery prior to surgery. Two AVM's were located on the cortex, three were found subcortically, and five were situated near the ventricles or in the deep white matter.

As a guide, angiography was used in six cases and CT in four cases. In each instance, the study providing the best image of the AVM nidus was employed. Postoperatively, no neurological deficits were found in eight patients and, in the two patients with preoperative deficits, neurological improvement was observed after recovery from surgery. Postoperative studies revealed complete removal of the AVM in all patients, and all lesions were confirmed histologically. The authors conclude that stereotactic craniotomy provides the optimum operative approach for the localization and microsurgical resection of AVM's that are either obscure or located deep in the brain.
Screening for unruptured asymptomatic intracranial aneurysms in patients undergoing coronary angiography
Authors: Iwata Kinzo , Misu Norio , Terada Kouichi , Kawai Sadami , Momose Motoichi , Nakagawa Hiroshi
Published: May 2009

✓ In screening for unruptured asymptomatic intracranial aneurysms, an intracranial intra-arterial digital subtraction angiography (IA-DSA), posteroanterior view, was obtained in 72 consecutive patients who underwent coronary angiography for workup of angina pectoris. In cases where an aneurysm was suspected from IA-DSA, conventional intracranial angiography was obtained. Five asymptomatic unruptured aneurysms were detected in four of these cases. The aneurysms ranged from 4 to 16 mm in diameter. There were no complications associated with the coronary angiography nor with the additional intracranial IA-DSA, which required less than 5 minutes to perform in all cases. The value of performing intracranial IA-DSA in patients undergoing coronary angiography to screen for unruptured asymptomatic aneurysm is discussed, as is the possible racial differences in the frequency of aneurysms.
Somatosensory evoked potentials in intracranial hypertension: analysis of the effects of hypoxia
Authors: Eldridge Paul R. , Hope D. Terence , Yeoman Patrick M. , Farquhar Iain K. , Mitchell Michael , Clarke Sharon A. , Smith N. Jollyon
Published: May 2009

✓ The loss of somatosensory evoked potentials (SSEP's) was investigated in a feline model of intracranial hypertension. Threshold values of cerebral perfusion pressure (CPP) and cerebral blood flow (CBF) required for maintenance of SSEP's are defined using a mathematical model. The model describes loss of amplitude of SSEP's using the form of a dose-response curve. Amplitude of the SSEP's declined to 50% of control values at a CBF of 15 ml/100 gm/min and a CPP of 20 mm Hg in the normoxic animal; in the presence of mild hypoxia (8 to 9 kPa), a significant increase in these values to 18 ml/100 gm/min and 32 mm Hg, respectively, occurred. No reliable changes in latency or central conduction time were demonstrated. It is concluded that, given adequate oxygenation, evoked electrical activity is lost at too low a level of CPP for this parameter to be useful in clinical monitoring. However, even mild hypoxia, when combined with intracranial hypertension, produces a major risk to neuronal integrity.
Deformity correction and long-term survival in an infant with iniencephaly
Authors: Gartman John J. , Melin Thomas E. , Lawrence W. Thomas , Powers Stephen K.
Published: May 2009

✓ The authors describe the case of a male infant who was diagnosed prenatally as having iniencephaly. Since birth, the child has grown, thrived, and undergone two successful operations to correct his cervical deformity. This case demonstrates that the iniencephaly defect is not uniformly fatal and that neurosurgical intervention may offer significant improvement in the cervical deformity.
Isolated symptomatic cervical spinous process fracture requiring surgery
Authors: Hirsh Leonard F. , Duarte Luis E. , Wolfson Eric H. , Gerhard Wilhelm
Published: May 2009

✓ Isolated cervical spinous process fractures are common, but are usually considered to be inconsequential. Although such fractures may produce pain, complete recovery without residual symptoms is expected after conservative treatment, and neurological injury does not usually occur. The case of a patient with a persistently symptomatic C-2 spinous process fracture that required surgical treatment for pain relief is reported. A review of the pertinent literature illustrates with unusual clarity the interactions of social, political, and economic forces associated with this medical condition.
Paul Broca and the first craniotomy based on cerebral localization
Authors: Stone James L.
Published: May 2009

✓ Paul Broca (1824–1880) was a well-known French surgeon-anthropologist-neurologist. Best known for his work on cerebral cortical localization and speech mechanisms, Broca also carefully worked out skull and scalp localization for underlying cortical regions. In 1871, Broca treated a man who had sustained a scalp laceration from a blow to the head without loss of consciousness or skull fracture. The patient exhibited a nonfluent aphasia about 1 month after injury and became progressively obtunded and eventually comatose. Suspecting an intracranial abscess, Broca trephined at the region of the left third frontal convolution and drained an epidural abscess. The patient improved transiently but died a few days later. Autopsy showed a left-sided, predominantly frontal purulent meningoencephalitis. Broca's other neurosurgical contributions included various surgical cases, methods for scalp localization of the cerebral convolutions, extensive studies of skull and brain abnormalities, thermoencephalography, and the stimulation of younger surgical colleagues and neurologists to make practical use of cerebral localization.
The influence of volume on the tolerance of the brain to radiosurgery
Authors: Marks Lawrence B. , Spencer David P.
Published: May 2009

✓ Radiosurgery (delivery of a high dose of radiation to a small volume of the brain) is usually well tolerated since the volume of brain irradiated is small. Despite growing interest in radiosurgery, the influence of the volume of brain irradiated on the tolerance of the brain to radiation is not well understood. The results of six studies reporting clinically significant radiation reactions following radiosurgery for arteriovenous malformations are reviewed. In the combined series, 23 (9%) of 255 patients developed a clinically significant radiation reaction. The volume of brain irradiated and the dose delivered in each of these 23 patients are presented. The compiled data suggest that the previously presented guidelines may underestimate the risks of radiosurgery. Additional clinical and experimental data are needed to determine “safe” doses of radiation to be used during radiosurgery.
Phase I trial of tissue plasminogen activator for the prevention of vasospasm in patients with aneurysmal subarachnoid hemorrhage
Authors: Zabramski Joseph M. , Spetzler Robert F. , Lee K. Stuart , Papadopoulos Stephen M. , Bovill Edwin , Zimmerman Richard S. , Bederson Joshua B.
Published: May 2009

✓ Recent laboratory studies have demonstrated that intracisternal administration of recombinant tissue plasminogen activator (rt-PA) can facilitate the normal clearing of blood from the subarachnoid space and prevent or ameliorate delayed arterial spasm. The results of a preliminary Phase I trial of intracisternal rt-PA in 10 patients are reported with documented aneurysmal subarachnoid hemorrhage (SAH). All patients enrolled were classified as clinical Grade III or IV (according to Hunt and Hess) with thick clots or layers of blood in the basal cisterns and major cerebral fissures (Fisher Grade 3). Ventriculostomy and surgery for clipping of the aneurysms were performed within 48 hours of hemorrhage. In one patient, 10 mg rt-PA was instilled into the subarachnoid cisterns prior to closing the dura. In the remaining nine patients, a small silicone catheter was left in the subarachnoid space and rt-PA (5 mg in four cases or 1.5 mg (0.5 mg every 8 hours for three infusions) in five cases) was instilled 12 to 24 hours after surgery. Minor local bleeding complications were noted in all patients receiving 5 or 10 mg rt-PA. Oozing was noted at the operative incision site in four of five patients and at the ventriculostomy site in two patients. One patient developed a small epidural hematoma that was treated by delayed drainage. No bleeding complications were noted in the patients receiving the lower regimen of rt-PA (three infusions of 0.5 mg each). Serial coagulation studies demonstrated no evidence of systemic fibrinolysis. Analysis of cisternal cerebrospinal fluid samples revealed thrombolytic tissue plasminogen activator (t-PA) levels for 24 to 48 hours. Follow-up cerebral angiography 7 to 8 days after rupture disclosed mild to moderate spasm in nine patients, while one patient with hemorrhage from a posterior inferior cerebellar artery aneurysm had severe focal spasm of the vertebral arteries that was not symptomatic. These results suggest that postoperative treatment with rt-PA may be effective in reducing the severity of delayed cerebral vasospasm. The results of serial t-PA levels suggest that the lower dosage regimen with divided dosages at 8-hour intervals is well tolerated and that even lower dosages may be effective. Further studies are clearly indicated.
Histological grading and bromodeoxyuridine labeling index of astrocytomas
Authors: Labrousse François , Daumas-Duport Catherine , Batorski Leszek , Hoshino Takao
Published: May 2009

✓ The histological grade and the bromodeoxyuridine (BUdR) labeling index of 60 astrocytomas of “ordinary” cell types (fibrillary, protoplasmic, gemistocytic, and anaplastic astrocytomas and glioblastomas) were compared to determine whether the grading system reflects the proliferative potential of the tumors. The tumor grade was based on the presence or absence of four criteria (nuclear abnormalities, mitosis, necrosis, and vascular endothelial proliferation): Grade 1, no criterion, Grade 2, one criterion, Grade 3, two criteria; and Grade 4, three or four criteria. The BUdR labeling index, or percentage of S-phase cells, was calculated in paraffinembedded tumor sections after in situ labeling by intraoperative intravenous infusion of BUdR, 200 mg/sq m. Exponential regression analyses showed a positive correlation between the histological grade and labeling index (r = 0.88, p < 0.001) that was stronger than the correlations between log labeling index and age (r = 0.55, p < 0.001) and between grade and age (r = 0.55, p < 0.001). These results indicate that the histological grading system reflects the proliferative potential of “ordinary” astrocytomas.
The nature of congenital posterior cervical or cervicothoracic midline cutaneous mass lesions
Authors: Steinbok Paul , Cochrane D. Douglas
Published: May 2009

✓ Between 4% and 8% of cases of spina bifida cystica occur in a cervical or cervicothoracic location. Despite a large body of literature concerning spinal dysraphism, there has been little written specifically about patients afflicted with this disorder in a cervical location. Eight children who presented at birth with posterior cervical or cervicothoracic lumps, all of which represented a dysraphic state, are discussed. Two types of abnormalities were noted. Three patients had hydromyelia with an associated myelocystocele herniating posteriorly into a meningocele sac. In these three patients there was an associated Chiari II malformation and hydrocephalus. The other five children had a meningocele in which a band of tissue extended from the posterior aspect of the spinal cord through a defect in the bone and fascia to the posterior part of the meningocele sac itself. No patient had a lesion that could be described as a meningomyelocele. The investigation and surgical management of these conditions are discussed and the need for intradural exploration to untether the spinal cord in the cervical region is stressed.
Magnetic resonance imaging of the transverse atlantal ligament for the evaluation of atlantoaxial instability
Authors: Dickman Curtis A. , Mamourian Alexander , Sonntag Volker K. H. , Drayer Burton P.
Published: May 2009

✓ Twenty normal human subjects and 14 patients with upper cervical spine pathology were studied with axial high-field magnetic resonance (MR) imaging to examine the transverse atlantal ligament. Gradient-echo MR imaging pulse sequences provided reliable visualization of the transverse ligament, which exhibited low signal intensity and extended behind the dens between the medial portions of the lateral masses of C-1. The MR imaging characteristics of the transverse ligament were verified in clinical studies and in postmortem specimens. The clinical MR examinations defined 27 normal ligaments, three ligament disruptions, and four stretched rheumatoid ligaments. Atlantoaxial instability associated with transverse ligament rupture or ligamentous laxity required internal fixation. In contrast, fractures of C-1 or C-2 or atlantoaxial rotatory dislocations associated with an intact transverse ligament healed without instability or nonunion. The transverse ligament is the primary stabilizing component of C-1. The treatment of atlantoaxial instability has previously been based on criteria drawn from computerized tomography or plain radiographic studies, which only indirectly assess the probability of rupture of the transverse ligament. It is concluded that MR imaging accurately depicts the anatomical integrity of the transverse ligament. After transverse ligament failure, the remaining ligaments of the craniovertebral junction are inadequate to maintain stability. The presence of ligament disruption should be considered as a criterion for early fusion.
Grafting of perfused adrenal medullary tissue into the caudate nucleus of patients with Parkinson's disease
Authors: López-Lozano Juan J. , Bravo Gonzalo , Abascal Javier , _ _
Published: May 2009

✓ The authors report results obtained in 20 severely affected patients with Parkinson's disease (Grade IV or V) who received an autotransplant of perfused adrenal medullary tissue. This study seems to indicate that these autoimplants can improve the parkinsonian symptomatology and induce amelioration in the patients' performance of routine activities. All the symptoms analyzed showed improvement, although it differed in intensity and time of onset. Moreover, this improvement was accompanied by a reduction in the daily intake of L-dopa, with discontinuance of dopamine agonists and amantadine.

A number of medical complications were encountered, including three deaths, probably related to performing abdominal surgery in seriously affected parkinsonian patients who were unable to tolerate the discontinuance of their medication. The transient psychiatric disorders observed appeared to be related to the postoperative dose of L-dopa and/or anticholinergic agents administered, and diminished or disappeared when the doses were reduced.

The reasons for improvement, which was bilateral, remain unknown, although one cause may be the surgical trauma (minicaudotomy) together with the implantation of adrenal medullary tissue, which may promote the sprouting of surviving dopaminergic fibers. Moreover, in this series, perfusion of adrenal medulla increased the capacity for revascularization of the tissue and may have reduced the damaging effects of warm ischemia on the cells. This, together with the existence of fenestrated vessels, could hypothetically have served as an access point for drugs, and if the implanted cells were viable, they might have served to store and manufacture different factors and/or transmitters. These results as well as those of other groups justify the development of a controlled international clinical trial.
Cross-resistance patterns in ACNU-resistant glioma sublines in culture
Authors: Saito Yuji , Nakada Yosihiro , Hotta Takuhiro , Mikami Takasi , Kurisu Kaoru , Yamada Kenji , Kiya Katuzou , Kawamoto Keiichi , Uozumi Tohru
Published: May 2009

✓ Three ACNU-resistant clones (R1, R3, and R12) were isolated from 9L rat glioma cells under selection pressure of ACNU in vitro. The authors have investigated the mechanisms of resistance and characteristics of these clones at the cellular level by studying cross-resistance patterns to chemical and physical agents. Although these resistant sublines showed complete cross-resistance to methyl-chloroethylnitrosourea (MCNU), no cross-resistance was observed for other alkylating agents, while each of the resistant sublines showed partial cross-resistance to structurally dissimilar toxic agents (vinblastine, Adriamycin, and VP-16). No difference in ACNU uptake was observed between 9L and R3 cells, and resistance patterns among alkylating agents suggested that the mechanism of ACNU resistance was specific to bifunctional nitrosoureas. Based on a transport study, this multidrug resistance could be explained by reduced intracellular uptake of these drugs, but there seemed little possibility that membrane P-glycoprotein, which usually is observed in typical multidrug-resistant cells, was expressed in these ACNU-resistant cells because enhanced drug efflux was not found in ACNU-resistant sublines. Significant collateral sensitivity to L-asparaginase indicated that ACNU might disturb the asparagine synthetic pathways by its mutagenic action. The increased level of total glutathione in the resistant sublines may be one mechanism of radiation or ACNU resistance.
Response of low-passage human malignant gliomas in vitro to stimulation and selective inhibition of growth factor-mediated pathways
Authors: Pollack Ian F. , Randall Margaret S. , Kristofik Matthew P. , Kelly Robert H. , Selker Robert G. , Vertosick Frank T.
Published: May 2009

✓ The proliferation of many nonglial tumors in vitro depends on the presence of nanomolar concentrations of one or more growth factors. To define the growth factor requirements of malignant glial tumors, the authors examined the response properties of four low-passage human malignant glioma lines to the following mitogens: epidermal growth factor (EGF), acidic and basic fibroblast growth factors (FGF's), insulin-like growth factor I (IGF-1), nerve growth factor (NGF), platelet-derived growth factor (PDGF), 12-0-tetradecanoyl-13-phorbol acetate (TPA), and serum. Each of the tumors showed increased deoxyribonucleic acid (DNA) synthesis (assessed by acid-precipitable [3H]-thymidine incorporation) in response to PDGF with a maximum effect at 50 ng/ml. Three tumors responded to EGF, three to IGF-I, two to acidic FGF, two to basic FGF, and two to TPA with maximum effects at 10, 50, 1, 1, and 10 ng/ml, respectively. None of the tumors responded to NGF. In the responsive tumors, optimum concentrations of EGF, IGF, TPA, acidic FGF, and basic FGF induced, at most, a two- to fourfold increase in [3H]-thymidine incorporation, which was only 30% to 50% of the response seen in 10% serum. In contrast, PDGF increased DNA synthesis eight- to 10-fold, equaling the effect of 10% serum. Measurements of cell proliferation also demonstrated a significant response to PDGF in each of the tumors. Appropriate concentrations of an anti-PDGF neutralizing antibody inhibited baseline DNA synthesis and proliferation in the absence of added growth factors, suggesting the possible role of PDGF in autocrine stimulation of these cells. However, this antibody produced only slight inhibition of seruminduced mitogenesis. Trapidil, an agent reported to inhibit the effects of PDGF, and polymyxin B, an inhibitor of protein kinase C, strongly inhibited baseline as well as PDGF- and serum-induced mitogenesis. It is concluded that, in the malignant gliomas studied, PDGF may be acting as a dominant mitogen to enhance DNA synthesis, and may function in autocrine stimulation. However, other factors contained in serum can also contribute to cell division.
Coronary vasospasm following subarachnoid hemorrhage as a cause of stunned myocardium
Authors: Yuki Kiyoshi , Kodama Yasunori , Onda Jun , Emoto Katsuya , Morimoto Tadao , Uozumi Tohru
Published: May 2009

✓ A patient with subarachnoid hemorrhage was found to have electrocardiographic abnormalities resembling an acute myocardial infarction as well as left ventriculographic findings of cardiac dysfunction. These cardiac abnormalities resolved following surgical clipping of the aneurysm and the patient recovered well from the operation. She died 2 months later from cancer and a postmortem examination at that time revealed no evidence of myocardial necrosis. In this report, the authors discuss coronary vasospasm and reversible postischemic “stunned myocardium,” a condition that has not been considered previously in relation to subarachnoid hemorrhage.
Spinal intramedullary ependymal cyst
Authors: Robertson Daniel P. , Kirkpatrick Joel B. , Harper Richard L. , Mawad Michel E.
Published: May 2009

✓ Three cases of spinal intramedullary ependymal cyst, two at the thoracolumbar junction and one in the cervical spinal cord, are reported in women in their fifth to seventh decades. Neurological signs and symptoms were extremity dysesthesias, paresthesias, and weakness. Plain cervical and lumbothoracic x-ray films were normal for the patients' age. Magnetic resonance (MR) imaging demonstrated a rounded cystic intramedullary mass at the thoracolumbar junction in two cases and at C3–7 in one case. The signal intensity of the cyst contents approximated that of cerebrospinal fluid on T1- and T2-weighted images. Upon administration of gadolinium-diethylenetriaminepenta-acetic acid (Gd-DTPA), MR imaging showed no enhancement in the cyst wall or cavity. Myelotomy and cyst drainage were performed in each case, and the neurological status of each patient improved. The lining of the cyst was biopsied in one of the three patients undergoing surgery and was composed of a single layer of cuboidal cells supported by glial tissue. Periodic acid-Schiff staining of the tissue did not reveal a basement membrane. The findings in these cases suggest that the Gd-DTPA-enhanced MR imaging appearance of intramedullary spinal ependymal cyst is consistent and allows for accurate preoperative diagnosis with or without biopsy.
Cervical paraganglioma with subsequent intracranial and intraspinal metastases
Authors: Blades Deborah A. , Hardy Russell W. , Cohen Mark
Published: May 2009

✓ Paragangliomas, tumors derived from the extra-adrenal paraganglion system, have commonly been found in the retroperitoneum, abdomen, mediastinum, skull base, and neck. Rare intraspinal cases have included involvement of the cauda equina and filum terminale, and a recent case has been reported of thoracic cord paraganglioma with metastasis to the cauda equina. The authors present the case of a patient with a cervical paraganglioma who underwent subtotal resection followed by postoperative irradiation; she subsequently developed multiple intracranial and intraspinal metastases 7 months following the first decompression procedure.
Lateral parascapular extrapleural approach to the upper thoracic spine
Authors: Fessler Richard G. , Dietze Donald D. , Millan Michael Mac , Peace David
Published: May 2009

✓ The upper thoracic vertebrae are difficult to approach surgically because of the narrowing of the thoracic inlet, the proximity of the brachial plexus, and the parascapular shoulder musculature. A novel lateral parascapular extrapleural approach to the upper thoracic vertebrae is described. The parascapular shoulder musculature (trapezius, levator scapulae, and rhomboid muscles) is reflected off the spinous processes to the scapula as a musculocutaneous flap, preserving the neurovascular supply. The paraspinal musculature is mobilized and retracted, and the upper dorsal ribs are removed with caution to avoid injury to the C-8 and T-1 nerve roots. The rami communicantes are transected, and the sympathetic chain is displaced anterolaterally. The T2–4 vertebrae can be approached unobstructed. The T-1 nerve root obstructs posterolateral access to the T-1 vertebra, necessitating an inferolateral approach underneath the T-1 nerve root axilla.

Four patients with compressive myelopathy from upper thoracic vertebral metastases underwent neural decompression, vertebral reconstruction, and posterior spinal fixation with this approach. Their postoperative neurological status was either unchanged or improved. Complications included radiographic pleural effusion and superficial wound dehiscence; one patient required posterior spinal reinstrumentation for progressive kyphosis. One patient developed pneumonia 7 days postoperatively which was unresponsive to appropriate treatment.

It is believed that the anatomical limitations to this region have been overcome, and that excellent exposure of the T1–4 vertebrae for neural decompression and vertebral reconstruction can be performed safely. A major advantage is that posterior spinal fixation can be carried out simultaneously.
Microvascular decompression for hemifacial spasm
Authors: Nagahiro Shinji , Takada Akira , Matsukado Yasuhiko , Ushio Yukitaka
Published: May 2009

✓ To determine the causative factors of unsuccessful microvascular decompression for hemifacial spasm, the follow-up results in 53 patients were assessed retrospectively. The mean follow-up period was 36 months. There were 32 patients who had compression of the seventh cranial nerve ventrocaudally by an anterior inferior cerebellar artery (AICA) or a posterior inferior cerebellar artery. Of these 32 patients, 30 (94%) had excellent postoperative results. Of 14 patients with more severe compression by the vertebral artery, nine (64%) had excellent results, three (21%) had good results, and two (14%) had poor results; in this group, three patients with excellent results experienced transient spasm recurrence. There were seven patients in whom the meatal branch of the AICA coursed between the seventh and eighth cranial nerves and compressed the dorsal aspect of the seventh nerve; this was usually associated with another artery compressing the ventral aspect of the nerve (“sandwich-type” compression). Of these seven patients, five (71%) had poor results including operative failure in one and recurrence of spasm in four. The authors conclude that the clinical outcome was closely related to the patterns of vascular compression.
Optochiasmal arachnoiditis following muslin wrapping of ruptured anterior communicating artery aneurysms
Authors: McFadzean Robert M. , Hadley Donald M. , McIlwaine Gawn G.
Published: May 2009

✓ Optochiasmal arachnoiditis has been reported following treatment of ruptured intracranial aneurysms, particularly arising from the anterior communicating artery. It has been suggested that the accompanying loss of vision is due to a muslin-induced optic neuropathy. This paper considers five cases of this condition; the response to steroid therapy was beneficial in three cases. A review of the literature is included. The arachnoiditis is considered to be due to an inflammatory response to muslin gauze placed close to the optic nerves and chiasm.
Treatment of chronic pain by epidural spinal cord stimulation: a 10-year experience
Authors: Kumar Krishna , Nath Rahul , Wyant Gordon M.
Published: May 2009

✓ Epidural spinal cord stimulation by means of chronically implanted electrodes was carried out on 121 patients with pain of varied benign organic etiology. In 116 patients, the pain was confined to the back and lower extremities and, of these, 56 exhibited the failed-back syndrome. Most patients were referred by a pain management service because of failure of conventional pain treatment modalities. Electrodes were implanted at varying sites, dictated by the location of pain. A total of 140 epidural implants were used: 76 unipolar, 46 Resume electrodes, 12 bipolar, and six quadripolar. Patients were followed for periods ranging from 6 months to 10 years, with a mean follow-up period of 40 months. Forty-eight patients (40%) were able to control their pain by neurostimulation alone. A further 14 patients (12%), in addition to following a regular stimulation program, needed occasional analgesic supplements to achieve 50% or more relief of the prestimulation pain. Pain secondary to arachnoiditis or perineural fibrosis following multiple intervertebral disc operations, when predominantly confined to one lower extremity, seemed to respond favorably to this treatment. Uniformly good results were also obtained in lower-extremity pain secondary to multiple sclerosis. Pain due to advanced peripheral vascular disease of the lower limbs was well controlled, and amputation below the knee was delayed for up to 2 years in some patients. Pain due to cauda equina injury, paraplegic pain, phantom-limb pain, pure midline back pain without radiculopathy, or pain due to primary bone or joint disease seemed to respond less well. Patients who responded to preliminary transcutaneous electrical nerve stimulation generally did well with electrode implants. Notable complications included wound infection, electrode displacement or fracturing, and fibrosis at the stimulating tip of the electrode. Three patients in this series died due to unrelated causes. Epidural spinal cord stimulation has proven to be an effective and safe means of controlling pain on a long-term basis in selected groups of patients.

The mechanism of action of stimulation-produced analgesia remains unclear; further studies to elucidate it might allow spinal cord stimulation to be exploited more effectively in disorders that are currently refractory to this treatment modality.
Suppression by traumatic brain injury of spontaneous hemodynamic recovery from hemorrhagic shock in rats
Authors: Yuan X. Q. , Wade Charles E. , Clifford Charles B.
Published: May 2009

✓ The effects of brain trauma on cardiovascular and endocrine responses to hemorrhage were investigated. Forty anesthetized rats were randomly assigned to one of four groups of 10 rats each: a control group (Group C); a group with induction of hemorrhage at 16.2 ml/kg/10 min (Group H); a group with fluid-percussion brain injury at a peak pressure of 1.7 atm and an impulse duration of 25 msec (Group T); and a group receiving hemorrhagic shock following brain trauma (Group TH). Group C and T rats showed no significant alterations in cardiovascular function. At the end of hemorrhage there were no significant differences between Groups TH and H in the nadirs of mean arterial blood pressure (MABP) (mean values ± standard error of the mean: 42 ± 2 vs. 40 ± 4 mm Hg) and stroke volume index (SVI) (0.61 ± 0.11 vs. 0.66 ± 0.10 ml/bt/kg); however, 1 hour post-hemorrhage recovery was blunted in Group TH compared to Group H (MABP 56 ± 4 vs. 65 ± 3 mm Hg; cardiac index 182 ± 15 vs. 220 ± 15 ml/min/kg; and SVI 0.71 ± 0.06 vs. 0.81 ± 0.06 ml/bt/kg). Since the two groups showed no significant differences in heart rate, preload (central venous pressure), and afterload (systemic vascular resistance), the reduced cardiac index recovery in Group TH is believed due to the attenuation of cardiac contractile performance. The Group TH preparation potentiated hormonal responses to hemorrhage with significantly higher epinephrine and aldosterone levels than in Group H. Brain trauma enhanced the norepinephrine response to hemorrhage, even at an injury level that by itself did not result in an increase in this hormone. Group TH rats also had significantly lower blood pH and HCO3 levels. The data suggest that brain trauma suppresses MABP and cardiac index recovery after hemorrhage mainly by inhibiting cardiac contractile performance, probably due to high catecholamine levels and severe metabolic acidosis.
Traumatic pericallosal aneurysm in a patient with no major trauma
Authors: Senegor Moris
Published: May 2009

✓ The case of a young woman who developed a traumatic distal anterior cerebral artery (“pericallosal”) aneurysm from a roller-coaster ride is described. She presented with a subarachnoid hemorrhage (SAH) restricted to the interhemispheric fissure. The initial angiogram was normal but repeat angiography at 8 days revealed the aneurysm. After craniotomy and clipping the patient made a satisfactory recovery. This is the only reported case of a traumatic aneurysm arising under circumstances not usually considered as trauma. It raises questions about the pathophysiology of the formation of such aneurysms and suggests that traumatic pericallosal aneurysms should be considered in SAH of unknown etiology. This case provides further evidence that repeat angiography occasionally helps reveal an aneurysm when the initial study fails to do so.
Stabilization of traumatic atlanto-occipital dislocation
Authors: Belzberg Allan J. , Tranmer Bruce I.
Published: May 2009

✓ Traumatic atlanto-occipital dislocation is most often fatal. Consequently, there are only scattered case reports of patients surviving this injury, and treatment modalities are anecdotal and varied. The case of an 18-year-old woman who suffered an anterior atlanto-occipital dislocation as the result of a motor-vehicle accident is presented. Rigid posterior fixation and complete reduction of the dislocation were achieved using an anatomically contoured steel loop secured to the occiput and cervical vertebrae. The addition of cancellous bone to the graft afforded long-term stability. This operative treatment provided anatomical realignment of the dislocation and allowed early mobilization of the patient with the use of aggressive rehabilitation. Previously reported cases of patients surviving anterior atlanto-occipital dislocation are reviewed. The use of cervical traction, halo bracing, and operative stabilization is discussed.
Geniculate neuralgia: the surgical management of primary otalgia
Authors: Rupa Vedantam , Saunders Richard L. , Weider Dudley J.
Published: May 2009

✓ Intractable, unexplained deep-ear pain presents a rare, albeit significant problem in otolaryngological and neurosurgical practice. The authors review their experience with 18 cases of primary otalgia during the past 15 years. A total of 31 surgical procedures were performed. Seventeen patients had sequential rhizotomies and one patient had microvascular decompression alone. Based on the clinical diagnosis, the nerves sectioned were singly or in combination: the nervus intermedius (14 patients), geniculate ganglion (10 patients), ninth nerve (14 patients), 10th nerve (11 patients), tympanic nerve (four patients), and chorda tympani nerve (one patient). Microvascular decompression of the involved nerves was undertaken in nine patients, in whom vascular loops were discovered. Adhesions (six patients), thickened arachnoid (three patients), and benign osteoma (one patient) were other intraoperative abnormalities noted.

The overall success of these procedures in providing pain relief was 72.2%, and the mean follow-up period was 3.3 years (range 1 month to 14.5 years). There was no surgical mortality. Expected side effects were: decreased lacrimation, salivation, and taste related to nervus intermedius nerve section, and transient hoarseness and diminished gag related to ninth and 10th nerve section. Four patients developed sequelae consisting of sensorineural hearing loss, vertigo, and transient facial nerve paresis. One patient had a cerebrospinal fluid leak and another developed aseptic meningitis as postoperative complications. Except when primary glossopharyngeal neuralgia is the working diagnosis, a combined posterior cranial fossa-middle cranial fossa approach is recommended for adequate exploration and/or section of the fifth, ninth, and 10th cranial nerves as well as the geniculate ganglion and nervus intermedius.
Determination of cerebrospinal fluid shunt obstruction with magnetic resonance phase imaging
Authors: Drake James M. , Martin Alastair J. , Henkleman R. Mark
Published: May 2009

✓ The cerebrospinal fluid (CSF) flow rates in 12 patients with symptoms suggestive of CSF shunt obstruction were measured with magnetic resonance (MR) phase imaging. The shunts were imaged over the skull, just distal to any reservoir, using a curved surface coil. Images perpendicular to the direction of flow were made on a 1.5-tesla clinical unit with a flow-sensitive pulse sequence. The patients' ages ranged from 2 months to 28 years. All patients had ancillary investigations to determine the functional status of the shunt. No flow was detected in seven patients with blocked shunts. Flow rates between 3 and 40 cc/hr were found in three patients with functioning shunts. Two patients, one with a blocked shunt and one with a functioning shunt, could not be imaged due to motion artifact. Magnetic resonance phase imaging is a promising technique in the determination of CSF shunt obstruction.
Malignant astrocytomas: focal tumor recurrence after focal external beam radiation therapy
Authors: Liang Bertrand C. , Thornton Allan F. , Sandler Howard M. , Greenberg Harry S.
Published: May 2009

✓ Hochberg and Pruitt have reported glioblastomas recurring within 2 cm of the primary site in 90% of patients after whole-brain radiation therapy. They suggested that computerized tomography (CT) scan accuracy would permit smaller radiation fields. A treatment protocol with smaller-field focal brain irradiation following surgical resection is reported. The first 4500 cGy of radiation is focused to within a 3-cm margin around the tumor, with a 1500-cGy boost within a 1.5-cm margin. Forty-two patients with grade III or IV astrocytoma, treated with focal brain radiation therapy were reviewed retrospectively to assess patterns of tumor recurrence. Thirty patients received intra-arterial bromodeoxyuridine (BUdR) radiosensitization with focal brain radiation therapy, and 12 patients underwent conventional focal brain radiation therapy. Tumor margin was defined on preoperative and recurrence CT scans as the contrast-enhanced area; these were traced on acetate templates and compared with each other and with the actual scans.

In all 42 patients, the lesion recurred within a 2-cm margin of the original tumor. Four patients had two recurrent areas: the second area was within the 2-cm margin in two, and outside this margin in two. These results are similar to those of Hochberg and Pruitt. It is suggested that focal irradiation is now the optimal treatment for malignant astrocytoma. Since recurrences continue to be within the irradiated volumes, it appears that higher focal doses of radiation are appropriate for clinical treatment trials of malignant astrocytomas.
Medulloblastoma: freedom from relapse longer than 8 years — a therapeutic cure?
Authors: Belza Mark G. , Donaldson Sarah S. , Steinberg Gary K. , Cox Richard S. , Cogen Philip H.
Published: May 2009

✓ Seventy-seven patients presenting with medulloblastoma between 1958 and 1986 were treated at Stanford University Medical Center and studied retrospectively. Multimodality therapy utilized surgical extirpation followed by megavoltage irradiation. In 15 cases chemotherapy was used as adjunctive treatment. The 10- and 15-year actuarial survival rates were both 41% with an 18-year maximum follow-up period (median 4.75 years). There were no treatment failures after 8 years of tumor-free survival. Gross total removal of tumor was achieved in 22 patients (32%); the surgical mortality rate was 3.9%. No significant difference was noted in the incidence of metastatic disease between shunted and nonshunted patients. The classical form of medulloblastoma was present in 67% of cases while the desmoplastic subtype was found in 16%. Survival rates were best for patients presenting after 1970, for those with desmoplastic tumors, and for patients receiving high-dose irradiation (≥ 5000 cGy) to the posterior fossa. Although early data on freedom from relapse suggested a possible beneficial effect from chemotherapy, long-term follow-up results showed no advantage from this modality of treatment. The patterns of relapse and survival were examined; 64% of relapses occurred within the central nervous system, and Collins' rule was applicable in 83% of cases beyond the period of risk. Although patients treated for recurrent disease could be palliated, none were long-term survivors.

The study data indicate that freedom from relapse beyond 8 years from diagnosis can be considered as a cure in this disease. Long-term follow-up monitoring is essential to determine efficacy of treatment and to assess survival patterns accurately.
“Angioglioma” and the arteriovenous malformationglioma association
Authors: Lombardi Daniela , Scheithauer Bernd W. , Piepgras David , Meyer Fredric B. , Forbes Glenn S.
Published: May 2009

✓ The term “angioglioma” denotes a highly vascular glioma, most of which are low-grade lesions associated with a favorable prognosis. The authors encountered an example of this pathology, a cystic oligodendroglioma associated with prominent vasculature which both clinically and histologically mimicked an occult arteriovenous malformation (AVM). This case and reports of the association of AVM and glioma prompted a histological review of 1034 surgically resected AVM's, both angiographically occult and visible, among which no oligodendroglial or astrocytic forms of “angioglioma” were found. Eight cases were observed, however, wherein oligodendroglial cells were increased in number within or about the malformation. Two basic histological patterns of oligodendroglial cell excess were seen; one appeared to be malformative in nature with abnormal disposition of oligodendroglial cells being an integral part of the AVM, whereas in the other an apparent increase in cellularity seemed the result of chronic ischemia with condensation of white matter. It appeared that the areas of increased oligodendrocyte content seen in association with AVM are non-neoplastic lesions that exhibit two rather distinct histological patterns of differing origin.

In an effort to determine the frequency of “angioglioma,” the authors examined Tissue Registry data for several glioma groups in which highly vascular examples are prone to occur. Tumors selected for study included 104 cerebellar-type (pilocytic) astrocytomas, 82 oligodendrogliomas, and 51 supratentorial pilocytic astrocytomas. Histological hypervascularity mimicking a vascular malformation (that is, an “angioglioma”) was encountered in 5%, 4%, and 12% of the cases, respectively. Based upon clinical, radiological, and pathological reviews of these cases, as well as a careful review of the literature, it was concluded that 1) “angiogliomas” are neither rare nor represent a distinct clinicopathological entity; 2) in histological but not necessarily angiographic surgical terms, they represent simply highly vascular gliomas, usually of low grade; and 3) the clinicopathological and angiographic features as well as the prognosis of such lesions do not differ from those of similar gliomas without angioma-like vasculature. Finally, “angiogliomas” must not be confused with gliomas of high-grade malignancy which, due to neovascularity, may be highly vascular at angiography and at surgery.
Effects of recombinant human tumor necrosis factor on rodent gliomas and normal brain
Authors: Kiwit Jürgen C. W. , Schmitz Karl-Heinz , Daum Ludwig , Reifenberger Guido , Roosen Norbert
Published: May 2009

✓ In a study examining the possible therapeutic effects of recombinant human tumor necrosis factor-alpha (rHuTNF-α) on malignant gliomas without expression of tumor necrosis factor (TNF)-receptors, RG-2 glioma cells were tested in vitro as well as in a rat experimental glioma model. A growth inhibition assay revealed no inhibiting effect in vitro up to a concentration of 20 µg/ml rHuTNF-α. Receptor-binding studies showed that RG-2 cells did not present specific receptors for rHuTNF-α. The pharmacokinetics of rHuTNF-α after intravenous injection were studied with respect to serum, tissue, and brain tumor concentrations and showed increased glioma concentrations of (mean ± standard error of the mean) 0.47 ± 0.18 ng TNF/mg brain compared to 0.15 ± 0.05 ng TNF/mg brain in the normal contralateral hemisphere.

No therapeutic effect on solid RG-2 gliomas could be observed after stereotactic injection of 7.3 µg rHuTNF/10 µl buffer solution into the tumor in 10 animals. Immunohistochemical studies after stereotactic injection of rHuTNF-α showed total disappearance of the substance after 24 hours without internalization into tumor cells. Stereotactic injection of 7.3 µg rHuTNF10 µl into normal brain resulted in marked inflammatory response around the injection track, including microvascular thrombosis. These results demonstrate that rHuTNF has neither direct nor indirect cytotoxic activity on RG-2 glioma cells. Furthermore, before clinical use of rHuTNF-α in malignant gliomas, the authors suggest that receptor studies be done in each patient. In receptor-positive patients undergoing treatment with rHuTNF-α, precautions should be taken to prevent local encephalitic reactions.