bluuebunny/crossref_metadata_2025 huggingface dataset:
Cognitive impairment and adjustment in patients without neurological deficits after aneurysmal SAH and early operation
Authors: Ljunggren Bengt , Sonesson Bengt , Säveland Hans , Brandt Lennart
Published: May 2009

✓ The mortality rate has recently been reduced to only a small percentage of patients selected for early aneurysm surgery. Despite recovery without neurological deficits, however, a diffuse encephalopathy may remain, with emotional and psychological sequelae that will interfere with rehabilitation and social reintegration. The present study evaluates quality of life, degree of cognitive dysfunction, and adjustment of patients with a satisfactory neurological recovery after aneurysm operation in the acute stage following a major subarachnoid hemorrhage (SAH). Of 118 patients with a good neurological recovery, 40 patients were randomly sampled for a cross-sectional study and subjected to a questionnaire relating to their symptoms, a clinical interview, and a comprehensive neuropsychological investigation. The time interval between SAH and assessment varied between 14 months and 7 years, averaging 3½ years. By means of standardized psychometric testing of intellectual capacity, memory functions, visuo-spatial abilities, perceptual speed and accuracy, and concept formation, degrees of cognitive impairment ranging from slight to severe dysfunction were identified. The results suggest that these disturbances may be permanent. The degree of impairment appeared to correlate with the patients' age. Interview data revealed substantial post-hemorrhagic maladjustment with respect to vitality, social management, self-assertion, emotional control, temperament, mood, and cognitive abilities. These findings were considerably at variance with the symptoms reported. It is stressed that, in the absence of gross neurological deficits, vital information on post-hemorrhage adjustment and impairment may easily be overlooked due to psychological defensive measures. It remains an open question whether post-SAH encephalopathy is enhanced by surgery performed in the acute stage.
Intraoperative evoked potentials recorded in man directly from dorsal roots and spinal cord
Authors: Nashold Blaine S. , Ovelmen-Levitt Janice , Sharpe Robbin , Higgins Alfred C.
Published: May 2009

✓ Direct spinal cord surface recordings of evoked spinal cord potentials have been made in 26 patients during neurosurgical procedures for intractable pain. Monopolar recordings at the dorsal root entry zone after peripheral nerve stimulation have been made at multiple levels for segmental localization and to monitor the state of the afferent path and dorsal horn. Dorsal root and dorsal column conduction has been tested on diseased and intact sides. Normal afferent conduction velocity was found to have an overall mean of 61.33 m/sec for cervicothoracic and lumbosacral peripheral nerves, and 50 m/sec for the dorsal columns. The normal mean amplitude for the slow negative wave (N1) recorded at the root entry was 52.54 µV, while that for the dorsal column conducted response recorded within 4 cm of the stimulus point on the dorsal columns was 347.5 µV. Several different placements of stimulating and recording electrodes are described, as well as their application. An interpretation of the resulting data is proposed.
Thermographic imaging of cutaneous sensory segment in patients with peripheral nerve injury
Authors: Uematsu Sumio
Published: May 2009

✓ Sensory examination based on the patient's subjective assessment of symptoms may raise difficult questions about whether the individual's expressed complaint is based on organic nerve damage, psychogenic factors, or even malingering. A prototype computerized telethermograph has allowed clinical quantification of peripheral nerve injury. The system makes possible mapping and imaging of the damaged area, as well as skin temperature measurements. In normal persons, the skin temperature difference between sides of the body was only 0.24° ± 0.073°C. In contrast, in patients with peripheral nerve injury, the temperature of the skin innervated by the damaged nerve deviated an average of 1.55°C (p < 0.001). The new technique requires further refinement, but it appears that use of this method may be cost-effective in helping to resolve medicolegal conflicts concerning peripheral nerve injury.
Evaluation of the efficacy of intrathecal nimodipine in canine models of chronic cerebral vasospasm
Authors: Gioia A. Eric , White Richard P. , Bakhtian Bijan , Robertson James T.
Published: May 2009

✓ Previous studies have examined whether calcium antagonists given sublingually, intravenously, or orally affect an experimentally induced vasospasm. This study was designed primarily to determine the efficacy of nimodipine given intracisternally in reversing the cerebral vasospasm produced in dogs by the injection of 4 ml of autogenous blood into the cisterna magna. The magnitude of the vasospasm and the vascular response to nimodipine were determined arteriographically. One group of animals was studied acutely to determine the dose and pharmacodynamic effects of intrathecal nimodipine, a second group was studied 1 to 4 days after the intrathecal injection of blood, and a third group was studied 3 to 6 days after successive injections of cisternal blood given 48 hours apart. Some animals were studied further 24 hours after the nimodipine treatment. Intrathecal administration of 4 ml of 10−3 M nimodipine promptly and completely reversed the cerebral vasospasm in all groups. This effect lasted at least 4 hours but had disappeared by 24 hours. The intrathecal administration of nimodipine produced a transient drop in blood pressure. In contrast, nimodipine given sublingually (0.28 to 0.58 mg/kg) or intravenously (0.1 mg/kg) produced a persistent hypotensive effect without affecting the vasospasm. The results show that the presence of nimodipine in the cerebrospinal fluid will reverse the blood-induced vasospasm, and suggest that this calcium antagonist administered intrathecally would be an effective emergency treatment of cerebral arterial spasm.
The isolation and characterization of Ca++-accumulating subcellular membrane fractions from cerebral arteries
Authors: Barry Kevin J. , Mikkelsen Ross B. , Shucart William , Keough Ellen M. , Gavris Virginia
Published: May 2009

✓ A study was undertaken using differential centrifugation methods to isolate from rabbit cerebral arteries the subcellular microsomal protein fractions capable of actively sequestering Ca++. One isolated protein fraction displayed a relatively large adenosine triphosphate (ATP)-dependent Ca++-accumulating capacity that was completely inhibited by NaN3, and was therefore designated the “mitochondrial fraction.” Electron microscopy confirmed that this fraction consisted of numerous mitochondrial elements. Another isolated membrane fraction possessed a Ca++-accumulating capacity dependent on ATP and oxalate and only partially sensitive to NaN3. In the presence of mersalyl acid or the Ca++ ionophore, A23187, Ca++ uptake by this fraction was inhibited 98.0% and 87.4%, respectively. Electron microscopy revealed that this fraction consisted of numerous membrane vesicles, and measurements of Na+-K+-ATPase (adenosine triphosphatase) activity indicated minimal plasma membrane contamination. It was concluded that this microsomal fraction consisted primarily of sarcoplasmic reticulum. At physiological free [Ca++] levels, Ca++ uptake by this fraction was inhibited by norepinephrine through a process sensitive to tolazoline but not propranolol. The effects on Ca++ uptake of added cyclic adenosine monophosphate (cAMP) alone or with rabbit or bovine protein kinase were inconclusive. The organic Ca++ channel blockers, nifedipine and verapamil, significantly inhibited Ca++ uptake by sarcoplasmic reticulum.
Estrogen and progestin binding by cytosolic and nuclear fractions of human meningiomas
Authors: Martuza Robert L. , Miller Douglas C. , MacLaughlin David T.
Published: May 2009

✓ Frozen tissue samples were obtained from meningiomas in 42 patients. Both cytosolic and nuclear fractions were tested for estradiol and progestin binding using equilibrium binding assays. The results were correlated with the age of the patient and the histological type and cellular density of the tumor.

Cytosolic estradiol binding was noted in 25 (60%) of 42 tumors, with eight (19%) of the 42 having levels over 10 femtomoles (fM)/mg protein. Nuclear estradiol binding was detected in 16 (57%) of 28 tumors, with six (21%) of the 28 having levels over 10 fM/mg protein. Cytosolic progestin binding was noted in 16 (73%) of 22 samples, with levels in nine (41%) of 22 being greater than 10 fM/mg protein. There was no correlation between the level of cytoplasmic progestin binding and either the level of cytoplasmic estradiol binding or the level of nuclear estradiol binding. In several specimens, levels of cytoplasmic progestin binding in excess of 100 fM/mg protein were found in tissues demonstrating little or no estradiol binding by either the nucleus or the cytosol. This discrepancy differs from the situation found in other hormonally responsive tissues such as breast or uterus, and suggests either a possible derangement of the normal cellular hormonal control mechanism or that the measured hormone binder is a molecule other than a classical hormone receptor.
Benign metastasizing meningioma
Authors: Miller Douglas C. , Ojemann Robert G. , Proppe Karl H. , McGinnis Barry D. , Grillo Hermes C.
Published: May 2009

✓ A patient with a histologically benign intracranial meningioma was found, at the time of initial presentation, also to have a pulmonary tumor. Fine-needle aspiration cytology of the lung mass was consistent with metastatic meningioma. When resected, the pulmonary tumor was found to be histologically benign. The patient has remained well and disease-free for 28 months. Only four other patients with apparently benign metastasizing meningiomas have been described previously.
Transorbital intracavernous needle biopsy in painful ophthalmoplegia
Authors: Rowed David W. , Kassel Edward E. , Lewis Anthony J.
Published: May 2009

✓ Painful ophthalmoplegia due to lesions in the region of the anterior cavernous sinus and superior orbital fissure may elude early diagnosis. Principal disease categories to be considered in patients with this complaint are neoplasm, vascular lesion, and inflammation. Although high-resolution computerized tomography (CT) may be helpful, definitive diagnosis frequently requires histological examination of tissue. In suitable patients this may be obtained by transsphenoidal or orbital biopsy. The orbital fine-needle aspiration technique has been recommended, but experience with this method is limited, and a definitive diagnosis cannot always be reached. The authors have established that, in suitable patients, the fine-needle aspiration technique with CT guidance may also be employed safely and effectively for lesions of the anterior cavernous sinus.
Intraoperative echocardiographic control during ventriculoatrial shunt placement
Authors: Bosi Giuliano , Zorzi Emilio , Guerrini Pietro , Lintermans Jean P.
Published: May 2009

✓ A method for positioning the cardiac end of a ventriculoatrial shunt with the aid of echocardiography is described. This simple procedure has resulted in safe and accurate shunt placement in infants.
Embryonal central neuroepithelial tumors and their differentiating potential
Authors: Rubinstein Lucien J.
Published: May 2009

✓ The embryonal central nervous system (CNS) neoplasms are reviewed with special reference to their differentiating potential and in the light of current neuro-oncogenetic concepts partly derived from the experimental induction of neural tumors. The conceptual (and, occasionally, practical) distinction between adult-type and embryonal CNS tumors raises a complex problem, because neoplastic transformation essentially involves replicating stem cells in tissues of renewal and because in the human brain such cells are found mostly in the course of CNS development. A cytogenetic scheme is therefore needed to serve as a frame of reference for a classification of embryonal CNS tumors that will account for the different histological entities documented so far and for the range and the restrictions of their differentiating capabilities. Most embryonal CNS tumors can be fitted into such a scheme. The cerebral medulloepithelioma, the cerebral and cerebellar neuroblastomas, the primitive polar spongioblastoma, and the ependymoblastoma show characteristic morphological features and a correspondingly distinctive cellular differentiating potential. The differentiating capabilities of the cerebellar medulloblastoma, the pineoblastoma, and the retinoblastoma are also distinctive, and are apparently determined by the cytogenesis of the area of the CNS in which the tumors originate. The indiscriminate application of a simplistic concept that would include all the so-called “primitive neuroectodermal tumors” into a single neuroepithelial tumor entity is unlikely to bring further understanding to the problem.
Current application of “high-dose” steroid therapy for CNS injury
Authors: Braughler J. Mark , Hall Edward D.
Published: May 2009

✓ Although administration of glucocorticoid steroids is one of the most widely used therapeutic modalities for the clinical management of acute trauma of the central nervous system (CNS), controversy continues regarding their effectiveness. In essence, two viewpoints concerning their use exist. Some believe that despite their poor clinical record, the steroids nevertheless have a place in the treatment of human CNS trauma. In general, this group of clinical investigators uses the steroids primarily out of tradition, feeling that steroid therapy may be of some benefit. Unfortunately, confusion remains as to what constitutes an appropriate dose or regimen. In this regard, it has been suggested that the steroid dose be increased and the regimen intensified. Others believe that steroids should not be used. They contend that in view of their poor clinical record, it is unlikely that increasing the steroid dose or changing the dosing regimen will improve clinical efficacy, since steroids have already failed at what may be considered huge doses by glucocorticoid standards. Furthermore, it is contended that the side effects associated with large steroid doses reduce the margin of safety so as to make the steroids unsafe. Complicating these arguments is a body of experimental evidence that by and large strongly supports the utility of steroids for the acute treatment of CNS trauma. The intent of this article is to evaluate the current use of steroid therapy for CNS trauma from a purely pharmacological perspective, and to compare the steroids' experimental use with their clinical application.
Prediction of survival in glioma patients by means of positron emission tomography
Authors: Patronas Nicholas J. , Chiro Giovanni Di , Kufta Conrad , Bairamian Dikran , Kornblith Paul L. , Simon Richard , Larson Steven M.
Published: May 2009

✓ The aim of this study was to determine whether positron emission tomography (PET) with fluorine-18 (18F)-2-deoxyglucose (FDG) can be used as a prognostic test in patients with high-grade cerebral gliomas, regardless of the treatment given. Forty-five patients with astrocytoma Grade III or IV were included in this analysis. The mean survival time of patients with tumors exhibiting high glucose utilization as determined by PET-FDG was 5 months, whereas patients with gliomas showing lower glucose utilization had a mean survival period of 19 months. It is postulated that PET-FDG scans reflect the biological behavior of high-grade astrocytomas and may be used to predict the survival time of patients harboring such neoplasms.
Assessment of cardiac and respiratory function during surgery on patients with acute quadriplegia
Authors: Mackenzie Colin F. , Shin Baekhyo , Krishnaprasad Deepika , McCormack Frank , Illingworth William
Published: May 2009

✓ Cardiorespiratory function was assessed in 22 mechanically ventilated patients who underwent surgery within an average of 4.8 days following traumatic spinal cord injury at C3–7. A fluid challenge technique was used to derive right and left ventricular function curves and to assist in choice of therapy from four possible outcome responses. Both right and left ventricular stroke work increased but left ventricular stroke work was still lower than normal in six (27%) of 22 patients despite elevation of cardiac filling pressures. Pulmonary vascular resistance fell, but systemic vascular resistance was unchanged following fluid challenge. Respiratory function, including intrapulmonary shunt, lung/thorax compliance, dead space, and arterial pO2 and pCO2, were unchanged by fluid administration averaging 520 ml of plasma protein fraction in 12 minutes. The Bainbridge reflex was inoperative. There was no correlation between anesthetic agent, level or type of neurological deficit, and cardiorespiratory function. Left ventricular function was impaired so the use of peripheral vasoconstrictors that elevate systemic vascular resistance should be avoided in the management of spinal shock. Instead, myocardial depressants should be reduced and fluid replacement used to optimize cardiac function. Elevation of central venous or pulmonary capillary wedge pressures to 18 mm Hg should be used to reverse hypotension, acidosis, low venous pO2, or oliguria before institution of centrally acting inotropic therapy in the management of acute spinal cord injury.
Early cerebral blood flow and computerized tomography in predicting ischemia after cerebral aneurysm rupture
Authors: Knuckey Neville W. , Fox Richard A. , Surveyor Ivor , Stokes Bryant A. R.
Published: May 2009

✓ Cerebral blood flow (CBF) was measured during the 1st week of subarachnoid hemorrhage in 46 patients who were in a good clinical grade and had a proven ruptured intracranial aneurysm. The mean initial CBF in patients who developed cerebral ischemia was 42 ml/min−1/l00 gm brain−1, which was significantly lower than in patients who did not develop cerebral ischemia (49 ml/min−1/l00 gm brain−1). This reduced CBF was not secondary to raised intracranial pressure or angiographic spasm. Patients with a reduced CBF (less than 50 ml/min−1/100 gm brain−1) and diffuse subarachnoid blood on computerized tomography had a very high incidence (78%) of cerebral ischemia, despite a good clinical grade at the time of measurement. Serial CBF measurements are of value in monitoring the evolution of cerebral vasospasm.
Leukotriene production in gerbil brain after ischemic insult, subarachnoid hemorrhage, and concussive injury
Authors: Kiwak Kevin J. , Moskowitz Michael A. , Levine Lawrence
Published: May 2009

✓ A leukotriene-like immunoreactivity was measured by radioimmunoassay in the gerbil forebrain following ischemia and reperfusion, subarachnoid hemorrhage (SAH), or nonlethal concussive brain injury. In each paradigm an increase in immunoreactivity levels was found. Peak levels were reached 15 to 30 minutes after each insult, and slowly returned to baseline over the next 24 hours. The study supports the suggestion that cerebral vessels and circulating blood are capable of producing leukotrienes, and that a major source of production is a nonvascular component within gray matter, possibly the cortical neuron. Leukotrienes may play a role in the pathophysiology of cerebral edema formation, cerebral vasospasm, seizure activity, and other central nervous system abnormalities. These studies are the first to demonstrate leukotriene production in gerbil brain following SAH or concussive brain injury.
Reflex activity and axonal conduction in the L-7 spinal cord segment following experimental compression trauma
Authors: Nacimiento Amadeo C. , Bartels Matthias , Herrmann Hans-Dietrich , Loew Friedrich
Published: May 2009

✓ In cats in which the spinal cord was transected at C-1, the exposed L-7 spinal cord segment was compressed with an electromagnetically driven rod applied to the dorsal surface of the segment. With the magnitude of compression constant at 3 mm, the cord was compressed for durations of 50 msec, 0.5 sec, or 1.0 sec. Polysynaptic reflex discharges integrated in the injured segment and action potentials conducted in dorsal column axons traversing the same region were electrophysiologically measured before, during, and for 4½ hours after trauma. Structural changes were evaluated on frozen serial sections obtained both from compressed segments and from tissue adjacent to the injury. At a compression duration of 50 msec, the amplitude of evoked reflex activity decreased abruptly, and dorsal column axonal conduction was blocked for 1 minute following compression. This early-phase response was followed by partial recovery of both functions which persisted until the end of the experiment. Prolonging compression to 0.5 sec brought about a further decrease of polysynaptic reflex activity. Axonal conduction was also decreased, but not significantly. With compression lasting 1.0 sec, no significant changes in reflex discharges and axonal conduction occurred compared with those measured at 0.5 sec. Neither function was abolished, even after the longest compression time. Prolongation of compression significantly increased both the intensity and the spread of edema, whereas changes in hemorrhage were not significant. Thus, a plateau rather than a progressive increase in severity of functional and structural posttraumatic changes was reached by increasing the duration of compression. This injury model reduces the sources of variability found in other experimental compression trauma models and permits the quantitative assessment of basic spinal cord mechanisms and correlated histopathological changes in the same preparation following trauma.
Study of the motility and contractility of cultured brain-tumor cells
Authors: Koga Hiroaki
Published: May 2009

✓ The motility of cultured cells and contractility of their cytoplasmic microfilament system were studied in benign compared with malignant brain-tumor cells. Motility of cultured cells was continuously monitored in a perfusion chamber by a computerized microscope system equipped with an autotracking device. The contractility of the microfilament system was defined by the increase in cell motility when the cell was perfused with an antimicrofilamentous agent, cytochalasin B. The motility and contractility of malignant cells were greater than those of benign cells. The increased contractility of malignant astrocytoma cells was associated with conspicuous morphological changes on electron microscopy. No significant change was observed in the motility, contractility, or morphology in various cells during perfusion with an antimicrotubular agent, colchicine. The significant differences in the motility and contractility of benign compared with malignant cells are believed to originate from qualitative differences of the microfilament system.
Effect of diltiazem on experimental chronic cerebral vasospasm in the monkey
Authors: Frazee John G. , Bevan John A. , Bevan Rosemary D. , Jones K. Roy
Published: May 2009

✓ The influence of diltiazem on chronic cerebral vasospasm was studied following subarachnoid hemorrhage (SAH) in a primate model. The model mimics the human experience including the production of neurological deficits. Six monkeys were pretreated with diltiazem (25 mg/kg twice daily) for 2 days prior to surgical production of an SAH and for 5 days after the hemorrhage. This group was compared with six untreated monkeys that also sustained an SAH. The mean diameter of cerebral arteries measured at six angiographic sites was 60.6% of the pre-SAH diameter for the untreated group and 99.7% for the diltiazem-treated group. These values are significantly different (p < 0.0005). There was no neurological deficit in the pretreated animals. The mean diameter of the “most constricted vessel” in each experiment was 22% of the prehemorrhage diameter for the untreated and 84% for the treated group (p < 0.0005). Arterial pressure was unaffected by the dosage regimen. These experiments with this primate model of chronic cerebral vasospasm demonstrate that vascular narrowing and neurological deficit can be markedly attenuated by diltiazem pretreatment.
Variation in response to CCNU of glioblastoma multiforme in brain and cervical lymph node
Authors: Steinbok Paul , Dolman Clarisse L. , Goldie James H.
Published: May 2009

✓ The case is reported of a patient in whom a cervical lymph node metastasis decreased in size while the primary intracranial glioblastoma continued to grow during chemotherapy with CCNU (1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea). This is the first such case reported in humans. Possible explanations for this phenomenon are discussed.
Posttraumatic cerebrospinal fluid cyst of the orbit
Authors: Sibony Patrick A. , Anand Azad K. , Keuskamp P. Arjen , Zippen Allen G.
Published: May 2009

✓ A 27-year-old man sustained a fracture of the orbital roof and a basofrontal dural tear in a motor-vehicle accident. One week later, he developed an orbitocranial dural fistula manifested by an orbital cyst, pulsatile proptosis, and serous drainage from the eye. Specific diagnosis was established only after computerized tomography metrizamide cisternography demonstrated direct communication of the orbital cyst with the subarachnoid space. The pertinent literature is reviewed.
Malignant behavior of myxopapillary ependymoma
Authors: Davis Charles , Barnard Robin O.
Published: May 2009

✓ From a series of 66 cases of central nervous system ependymomas, three cases of well differentiated ependymoma of the cauda equina are described. These tumors recurred and spread to produce intracranial deposits. No extraneural lesions were found.
Familial pineoblastoma
Authors: Lesnick James E. , Chayt Karen J. , Bruce Derek A. , Rorke Lucy B. , Trojanowski John , Savino Peter J. , Schatz Norman J.
Published: May 2009

✓ Two cases of pineoblastoma are presented. One occurred in a 12-year-old girl and the other, 20 months later, in her 43-year-old mother. A possible genetic basis and mutual exposure to an environmental factor responsible for the expression of a tumor gene are postulated in the discussion.
Bipolar diathermy forceps with automatic irrigation
Authors: Ohta Tomio , Funatsu Noboru , Kuroiwa Toshihiko , Matsui Takayoshi
Published: May 2009

✓ A method for providing a saline drip during bipolar diathermy is described. Stainless steel tubing is incorporated in both blades of standard bipolar forceps and connected to the irrigating line. Irrigation is started when the forceps are closed and is stopped when they are open.
The pathogenesis of acromegaly
Authors: Laws Edward R. , Scheithauer Bernd W. , Carpenter Sandra , Randall Raymond V. , Abboud Charles F.
Published: May 2009

✓ A series of 75 patients with acromegaly and immunocytochemically characterized pituitary adenomas has been analyzed. Tumors secreting growth hormone (GH) only were found in 21% of cases. The remainder had tumors immunoreactive for more than one pituitary hormone: GH and prolactin in 31%; GH, prolactin, and glycoprotein in 40%; and GH and glycoprotein in 8%. Microadenomas were surgically treated in 17 patients with a success rate of 82%. Overall, normalization of basal GH secretion (to ≤ 5 ng/ml) was achieved in 54% of cases. The implications of these findings for the pathogenesis and neurosurgical management of acromegaly are discussed.
Pituitary enlargement mimicking pituitary tumor
Authors: Bilaniuk Larissa T. , Moshang Thomas , Cara Jose , Weingarten Martin Z. , Sutton Leslie N. , Samuel Lewis R. , Zimmerman Robert A.
Published: May 2009

✓ Primary hypothyroidism can result in reactive enlargement of the pituitary gland which is indistinguishable from primary pituitary lesions on computerized tomography (CT) scans. The presenting symptoms may be due to pituitary gland enlargement, as in two of the three cases reported here. Therefore, the diagnosis of pituitary hypertrophy or hyperplasia secondary to hypothyroidism must be based on the endocrinological work-up. Following treatment of primary hypothyroidism, the diminution in size of the pituitary gland can be demonstrated with CT.
Effect of mannitol on cerebral blood flow and cerebral perfusion pressure in human head injury
Authors: Mendelow A. David , Teasdale Graham M. , Russell Thomas , Flood John , Patterson James , Murray Gordon D.
Published: May 2009

✓ Patients with severe head injury frequently have evidence of elevated intracranial pressure (ICP) and ischemic neuronal damage at autopsy. Mannitol has been used clinically to reduce ICP with varying success, and it is possible that it is more effective in some types of head injury than in others. The aim of the present study was to determine the effect of mannitol on ICP, cerebral perfusion pressure (CPP), and cerebral blood flow (CBF) in patients with severe head injury, and to discover if these effects differed in different types of injury. Measurements of CPP, ICP, and CBF were made in 55 patients with severe head injury. In general, the resting level of CBF was higher in patients with diffuse injury (mean 50.2 ml/100 gm/min) than in those with focal injury (mean 39.8 ml/100 gm/min). Mannitol consistently reduced ICP and increased CPP and CBF by 10 to 20 minutes after infusion. The lowest flows (31.8 ml/100 gm/min) were recorded from the most damaged hemispheres of patients with focal injuries and elevated ICP. The baseline levels of flow did not correlate with ICP, CPP, Glasgow Coma Scale score, or outcome. Only four of the 55 patients had a CBF of less than 20 ml/100 gm/min in either or both hemispheres. The few low CBF's in this and other studies may reflect the steady-state conditions under which measurements are made in intensive care units, and that these patients have entered a phase of reperfusion.
Incidence of multiple intracranial aneurysms
Authors: Østergaard John R. , Høg Esben
Published: May 2009

✓ Theoretically, if arterial hypertension plays a role in aneurysm formation, it might also be associated with a higher incidence of multiple aneurysms as compared to their occurrence in normotensive patients. In an unselected series of 737 aneurysm patients, the structure of dependence between 1) number of aneurysms, 2) patients' sex, 3) patients' age, and 4) the presence or absence of hypertension was analyzed using contingency-table analysis. Evidence of arterial hypertension was determined by means of three complementary criteria of hypertension. A significant mutual state of dependence was demonstrated between the presence or absence of hypertension and the number of aneurysms, and between number of aneurysms and sex of the patient. In addition, for patients with a given number of aneurysms, the action of gender was independent of the blood pressure level. No interaction between the age of the patient and the number of aneurysms could be demonstrated. In order to quantify the relative contribution of the patients' sex, the patients' age, and the presence of hypertension to multiplicity of aneurysms, a probability model for multiplicity of aneurysms was estimated by logistic-regression analysis. It was demonstrated that the most important factor explaining multiplicity was the presence of hypertension, whereas the age of the patient had no influence. A “pure” effect of gender was revealed, indicating that females are significantly more susceptible to aneurysm formation, even in cases without arterial hypertension.
Human neonatal hydrocephalus
Authors: Del Bigio Marc R. , Bruni J. Edward , Fewer H. Derek
Published: May 2009

✓ An infant of 43 weeks gestational age with severe congenital hydrocephalus was operated on for removal of a subependymal astrocytoma in the region of the foramen of Monro. A biopsy of periventricular tissue was taken from the lateral ventricle for examination by scanning and transmission electron microscopy. The ependyma was largely denuded, with glial cell processes forming most of the ventricular lining. Many of the attenuated ependymal cells, however, had intact junctional complexes at areas of contact with other ependymal cells. Club-shaped unipolar cells, believed to be a previously undescribed form of immature ependymal cells, were found in the ventricular lining. Cerebrospinal fluid edema was present in the neuropil up to 60 µm from the ventricular lumen, but there was no obvious axonal pathology in the tissues examined.
Brain specific gravity and CT scan density measurements after human head injury
Authors: Bullock Ross , Smith Roger , Favier Jean , du Trevou Michael , Blake Gordon
Published: May 2009

✓ White matter specific gravity was measured using the microgravimetric method in 20 comatose patients with diffuse head injury who were undergoing intracranial pressure (ICP) monitoring, and in 19 patients with focal injuries who were undergoing evacuation of contusions or intracerebral hematomas. Computerized tomography (CT) density readings were obtained for each site of white matter sampling by locating the sampling site on the preoperative CT scan. A significant correlation was found between the specific gravity values and the CT density numbers (r = 0.775; p < 0.001). Patients with focal injuries demonstrated reduced perifocal specific gravity, suggesting brain edema. The mean specific gravity in patients with diffuse injury was within the normal range. In 10 of 12 patients in whom the specific gravity was above the normal range, the CT density was also above the normal range. These data suggest that cerebral vascular engorgement is the cause of the high specific gravity. Six (60%) of this small subgroup of 10 patients also demonstrated a high ICP.
Biomechanical and hydrodynamic characterization of the hydrocephalic infant
Authors: Shapiro Kenneth , Fried Arno , Marmarou Anthony
Published: May 2009

✓ The pressure-volume index (PVI) technique of bolus manipulation of cerebrospinal fluid (CSF) was used to measure neural axis volume-buffering capacity and resistance to the absorption of CSF in 16 hydrocephalic infants prior to shunting.

The mean steady-state intracranial pressure (ICP) was 11.7 ± 5.7 mm Hg (± standard deviation (SD)), representing a modest elevation of ICP in infants. The mean measured PVI was 28.1 ± 1.5 ml (± standard error of the mean (SEM)) compared to the predicted normal level for these infants of 12.1 ± 2.7 ml (± SD) (p < 0.001). This resulted from an enhanced volume storage capacity in the hydrocephalic infants. The PVI was not related to ventricular size in these hydrocephalic infants. Although absorption of the additional bolus of fluid did not occur at steady-state ICP, it was readily absorbed once ICP was raised above a mean threshold pressure of 16.0 ± 5.0 mm Hg (± SD) in 13 of the 16 infants. Above this pressure, the mean CSF absorption resistance was 7.2 ± 1.3 mm Hg/ml/min (± SEM) which is twice the normal values as measured by the bolus injection technique.

The biomechanical profile of infantile hydrocephalus described in this study indicates that two factors are required for progression of ventricular volume. While an absorptive defect may initiate the hydrocephalic process, progressive volume storage requires an alteration in the mechanical properties of the intracranial compartment.
Concussive head injury producing suppression of sensory transmission within the lumbar spinal cord in cats
Authors: Katayama Yoichi , Glisson James D. , Becker Donald P. , Hayes Ronald L.
Published: May 2009

✓ This study examines the effects of concussive levels of a fluid-percussion head injury on sensory transmission within the lumbar spinal cord of the cat. Primary afferent depolarization (PAD) was suppressed for 2 to 5 minutes following injury, as assessed by dorsal root potentials and augmentation of antidromic dorsal root potentials, both evoked by stimulation of adjacent dorsal roots. Polysynaptic reflex discharges in ventral root potentials evoked by dorsal root stimulation were also profoundly suppressed during this same period, even when spontaneous and monosynaptic reflex discharges were facilitated. Changes in PAD produced by injury were abolished by spinal cord transection, but were not affected by midpontine transection. These findings suggest that concussive head injury can produce suppression of segmental sensory transmission by neurally mediated processes involving the bulbar brain stem. Recordings of dorsal root resting potentials, antidromic dorsal root potentials, and reductions of antidromic dorsal root potentials induced by tetanic root stimulation indicated that depressed segmental sensory function produced by injury was due to suppression of postsynaptic interneuronal transmission rather than to excitability changes in primary afferent fibers. Somatosensory cortical potentials evoked by dorsal root stimulation were profoundly depressed at the same time as segmental sensory transmission was suppressed, suggesting that suppressed segmental sensory transmission may also contribute to suppression of ascending sensory transmission. It is hypothesized that transmission failure of interneuronal systems in the initial period following insult may be a general response occurring in wide areas of the central nervous system, and not restricted to areas to which mechanical stress is directly applied. This response pattern may result from indiscriminate activation of interconnected excitatory and inhibitory elements of interneuronal systems.
Changes in contralateral brain-stem auditory evoked responses to cerebellopontine angle compression in rats
Authors: Zappulla Rosario A. , Wang Zhong Zhi , Malis Leonard I. , Karmel Bernard Z.
Published: May 2009

✓ Eleven rats were subjected to graded compression of the brain stem at the cerebellopontine angle (CPA) following craniectomy and cerebellectomy. Clicks were delivered to the ear contralateral to the compression site, and brain-stem auditory evoked responses (BAER's) were collected before and during compression. With increasing compression, there was an increase in the latency and a decrease in the amplitude of the peaks of the BAER. The later peaks of the BAER (V and VI) demonstrated changes with minimal compression that progressed as compression increased, while changes in the amplitude and latency of the earlier peaks (II, III, and IV) occurred at the higher grades of compression. Following decompression of the brain stem, there was a decrease in the latencies of most of the BAER peaks. Peak amplitude remained depressed following brain-stem decompression.

These experimental findings corroborate clinical reports of abnormal BAER's elicited from stimulation of the ear contralateral to a CPA tumor. The relative sensitivity of the later peaks of the BAER to even minimal brain-stem compression explains the prolonged III to V interpeak latency reported in the literature in patients with brain-stem compression from a CPA lesion. The possible mechanisms for the BAER changes that were observed contralateral to compression are discussed.
Nonsurgical treatment of subdural empyema
Authors: Mauser Henk W. , Ravijst Robert A. P. , Elderson Arthur , van Gijn Jan , Tulleken Cees A. F.
Published: May 2009

✓ The nonsurgical treatment of a case of interhemispheric subdural empyema is reported. At the time of diagnosis, the patient had a mild decrease in consciousness and only moderate focal neurological deficits. Computerized tomography (CT) confirmed the limited (interhemispheric) extent of the intracranial infection. After drainage of the nasal sinuses and antibiotic treatment, the patient recovered, although the lesion was initially increased in size on CT scanning.
Bayonette curettes for anterior cervical spine procedures
Authors: Sisco Alton Brown , Tippett Troy M. , Chapleau Charles E.
Published: May 2009

✓ A modification of the shape of currently available curettes is described that facilitates anterior cervical procedures performed with the operating microscope.
Preservation of hearing in patients undergoing excision of acoustic neuromas and other cerebellopontine angle tumors
Authors: Tator Charles H. , Nedzelski Julian M.
Published: May 2009

✓ Microsurgical techniques have made it possible to identify and preserve the cochlear nerve from its origin at the brain stem and along its course through the internal auditory canal in patients undergoing removal of small or medium-sized acoustic neuromas or other cerebellopontine angle (CPA) tumors. In a consecutive series of 100 patients with such tumors operated on between 1975 and 1981, an attempt was made to preserve the cochlear nerve in 23. The decision to attempt to preserve hearing was based on tumor size and the degree of associated hearing loss. In cases of unilateral acoustic neuroma, the criteria for attempted preservation of hearing were tumor size (2.5 cm or less), speech reception threshold (50 dB or less), and speech discrimination score (60% or greater). In patients with bilateral acoustic neuromas or tumors of other types, the size and hearing criteria were significantly broadened. All patients were operated on through a suboccipital approach.

Hearing was preserved postoperatively in six (31.6%) of the 19 patients with unilateral acoustic neuromas, although the cochlear nerve was preserved in 16. Of the six patients with postoperative hearing, three retained excellent hearing, and the other three had only sound awareness and poor discrimination. Hearing was preserved in three cases with other CPA tumors, including an epidermoid cyst and small petrous meningiomas in the internal auditory canal. Of the two cases with bilateral tumors, hearing was preserved in one. Of the 23 patients in whom hearing preservation was attempted, nine (39.1%) had some postoperative hearing, which in six was equal to or better than the preoperative level. Thus, it is worthwhile to attempt hearing preservation in selected patients with CPA tumors.
Intracranial pressure monitoring by flaccid-cuff catheter in an animal model
Authors: Miller Jimmy D. , Pattisapu Jogi , Peeler Dudley F. , Parent Andrew D.
Published: May 2009

✓ Several methods of monitoring intracranial pressure (ICP) are in current use, each with its own advantages and disadvantages. The intraventricular line has been most useful because of the ability to withdraw cerebrospinal fluid to assist in control of elevated ICP. However, masses within the brain or generalized increased ICP may compress the lateral ventricle, making insertion of the catheter difficult or impossible. The intracerebral wick records hydrostatic changes too slowly to be used clinically. Swollen cerebral tissue may occlude the subarachnoid bolt thereby dampening the recorded pressure, and epidural monitors may give falsely high recordings because of irregularities of dura or bone. The authors have developed a flaccid-cuff catheter which has proven in animals to be an effective ICP monitor. There are several advantages, such as easy insertion into the centrum semiovale, rapid response to acute pressure changes, and continued sensitivity for periods of up to 3 weeks. The flaccid catheter cuff has no tension so that the pressure across the membrane is equal to zero, simplifying calibration. This type of cuff is necessary for maximum sensitivity to interstitial, brain-tissue, and gross ICP changes. The flaccid-cuff catheter may prove to be useful in a variety of situations such as after closed head trauma or intracranial surgery to assess elevated ICP caused by edema or evolving hematoma.
Effects of potassium channel-blocking agents on spontaneous discharges from neuromas in rats
Authors: Burchiel Kim J. , Russell Lisa C.
Published: May 2009

✓ Thirty-five Sprague-Dawley rats with saphenous neuromas underwent acute microfilament recording in the proximal nerve. The effect of the potassium channel-blocking agents, tetraethylammonium bromide (TEA) and 4-aminopyridine, on spontaneous activity in A fibers terminating in the neuroma was observed. The effects of gallamine were also tested. Of the two channel-blocking agents, TEA reliably increased spontaneous firing in active fibers and initiated spontaneous activity in some fibers with no spontaneous baseline discharge. 4-Aminopyridine had no effect on baseline activity of either spontaneously active or quiescent fibers; however, it inhibited spontaneous activity induced by prior TEA treatment. Gallamine application produced effects similar to TEA in that spontaneous activity was dramatically increased. These results imply that a tonic potassium conductance is present in regenerating fibers in the neuroma and that this conductance moderates the tendency toward hyperexcitability and spontaneous firing. Spontanous activity in nociceptive afferent fibers may represent the mechanism of chronic pain and paresthesias that often accompany peripheral nerve injury. These results suggest that agents which either increase potassium conductance or selectively inhibit the sodium current in regenerating axons might be effective in the treatment of these chronic pain syndromes.
Increase in rat spinal cord blood flow with the calcium channel blocker, nimodipine
Authors: Guha Ab , Tator Charles H. , Piper Ian
Published: May 2009

✓ Nimodipine, a calcium channel blocker, is known to increase cerebral blood flow. In the present study, the authors investigated the effect of nimodipine on spinal cord blood flow in normal rats. Cardiovascular parameters, including mean systemic arterial blood pressure, cardiac output, and heart rate, were recorded during infusion of nimodipine in a dose-response fashion. The experiment was a randomized blind study in which four groups of five rats received different doses of nimodipine (0.001, 0.01, 0.05, and 0.10 mg/kg) intravenously over 30 minutes, and a control group of five rats received only the diluent. The hydrogen clearance and thermodilution techniques were used to measure spinal cord blood flow and cardiac output, respectively.

The 0.05-mg/kg dose of nimodipine caused the largest increase in spinal cord blood flow, with a 40% increase over the preinfusion level, although there was a 25% reduction in mean arterial pressure. The 0.10-mg/kg dose did not increase spinal cord blood flow more than the 0.05-mg/kg dose, most likely due to the concomitant 37% reduction in mean arterial pressure. Cardiac output was significantly increased by the 0.05- and 0.10-mg/kg doses secondary to the drop in total peripheral resistance. The increase in spinal cord blood flow produced by nimodipine lasted approximately 20 minutes after the termination of the infusion. Thus, nimodipine at a dose of 0.05 mg/kg markedly increased blood flow in the normal spinal cord even though there were major changes in mean systemic arterial pressure and cardiac output. Further research is required to determine whether this drug might be beneficial in treating ischemic states of the spinal cord, such as posttraumatic ischemia.