bluuebunny/crossref_metadata_2025 huggingface dataset:
Pachymeningitis cervicalis hypertrophica
Authors: Rosenfeld Jeffrey V. , Kaye Andrew H. , Davis Stephen , Gonzales Michael
Published: May 2009

✓ The authors present the case of a 25-year-old man with idiopathic pachymeningitis hypertrophica that caused cervical radiculopathy. Decompressive surgery produced significant neurological improvement. The etiology and management of the condition are discussed and the literature is reviewed.
A direct transnasal approach to the sphenoid sinus
Authors: Griffith Huw B. , Veerapen Richard
Published: May 2009

✓ The transsphenoidal route to the pituitary gland is well established in neurosurgical practice, and several approaches to the sphenoidal air sinus have been described. In this paper, the authors describe a technique that utilizes a direct route through the nasal cavity, thereby minimizing disruption of normal tissues.
In vitro drug sensitivity testing in human gliomas
Authors: Kimmel David W. , Shapiro Joan R. , Shapiro William R.
Published: May 2009

✓ In vitro drug sensitivity assays have been developed with the goal of predicting the clinical response to chemotherapy. The colony-forming assay, radiolabeled precursor inhibition assay, and microcytotoxicity assay are most commonly used. In retrospective studies, the assays correctly predict clinical response to a chemotherapeutic agent in 50% to 70% of patients and predict clinical resistance in nearly 100% of patients. All of the assays suffer from technical and theoretical problems. In vitro assays depend on cell culture and therefore do not entirely simulate in vivo conditions. Heterogeneity in chemosensitivity is commonly found and can complicate the interpretation of results. Further investigation is needed to determine if these assays will be able to select prospective chemotherapy for patients. The malignant origin of the cells in culture must be verified if meaningful conclusions are to be made.
Principles of preparation of vein bypass grafts to maximize patency
Authors: Sundt Thoralf M. , Sundt Thoralf M.
Published: May 2009

✓ Experience in cardiovascular and peripheral vascular surgery with saphenous vein bypass conduits is reviewed. It is clear that meticulous technique and graft preparation are crucial to short-term and long-term patency. The risk of early thrombosis is related to damage to the graft 's native intima, graft flow, and coagulability of the patient 's blood. Attention to atraumatic harvesting techniques and perfection of anastomoses are crucial to minimizing intimal damage. Graft inflow and outflow are fundamental principles. The use of vitamin K antagonists and platelet inhibitors may improve graft survival. Subacute occlusion is related to structural alterations in the grafts themselves. These include intimal hyperplasia and medial fibrosis as the grafts become “arterialized,” valve fibrosis, aneurysmal dilatation, clamp stenosis, and suture stenosis. Long-term patency is threatened primarily by atherosclerosis in the graft itself. There is some evidence that care in vein harvesting and implantation as well as the use of anticoagulant agents affect the development of this complication.

A technique for graft preparation is presented that is based on the experience of the authors in harvesting grafts for both cerebral and coronary bypass conduits.
Intracranial carotid artery injury in closed head trauma
Authors: Morgan Michael K. , Besser Michael , Johnston Ian , Chaseling Raymond
Published: May 2009

✓ Six patients with trauma to the intracranial internal carotid artery are reported. One patient died and two are permanently disabled due to ischemic sequelae. The incidence of this complication of trauma is unknown because of the infrequent use of angiography in head-injured patients. The pathology, clinical course, and management of this condition are discussed with reference to the 25 previously reported cases in addition to the six in this series.
Giant intracranial varices secondary to high-flow arteriovenous fistulae
Authors: ViñUela Fernando , Drake Charles G. , Fox Allan J. , Pelz David M.
Published: May 2009

✓ An intracranial varix is rare and has been associated mostly with vein of Galen fistulae or arteriovenous (AV) malformations. The authors present eight cases of intracranial, pial or subpial AV fistulae with concomitant giant varices. Six were supratentorial and two were infratentorial. Only one case involved the vein of Galen. In six cases successful surgical and/or endovascular occlusion of the intracranial AV fistula was obtained, and one case was treated conservatively. Staging of surgery and postoperative hypotension were considered to be important in avoiding edema and hemorrhage following obliteration of a large AV shunt. One patient died from delayed postoperative intracerebral bleeding.
A new approach in the treatment of hydrocephalus
Authors: Sainte-Rose Christian , Hooven Michael D. , Hirsch Jean-François
Published: May 2009

✓ To date, most patients suffering from hydrocephalus have been treated by insertion of differential-pressure valves that have fairly constant resistance. Since intracranial pressure (ICP) is a variable parameter (depending on such factors as patient's position and rapid eye movement sleep) and since cerebrospinal fluid (CSF) secretion is almost constant, it may be assumed that some shunt complications are related to too much or too little CSF drainage. The authors suggest a new approach to treating hydrocephalus, the aim of which is to provide CSF drainage at or below the CSF secretion rate within a physiological ICP range. This concept has led the authors to develop a three-stage valve system. The first stage consists of a medium-pressure low-resistance valve that operates as a conventional differential-pressure valve until the flow through the shunt reaches a mean value of 20 ml/hr. A second stage consists of a variable-resistance flow regulator that maintains flow between 20 and 30 ml/hr at differential pressures of 80 to 350 mm H2O. The third stage is a safety device that operates at differential pressures above 350 mm H2O (inducing a rapid increase in CSF flow rate) and therefore prevents hyper-elevated ICP. An in vitro study is described that demonstrates the capability of this system to maintain flow rates close to CSF production under a range of pressures similar to those observed under various human physiological and postural conditions. Promising clinical results in 19 patients shunted with this valve are summarized.
Modulation in vitro and in vivo of ACNU resistance in a subline of C6 glioma with reserpine
Authors: Yoshida Tatsuo , Shimizu Keiji , Ushio Yukitaka , Mogami Heitaro , Sakamoto Yukiya
Published: May 2009

✓ Reserpine enhanced in vitro the cytotoxicity of 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) in both the C6 glioma and its ACNU-resistant subline, C6/ACNU. Reserpine also enhanced the chemotherapeutic effect of ACNU in C6/ACNU-bearing (C6/ACNU-meningeal gliomatosis) rats, in which ACNU resistance could be modulated by combined ACNU and reserpine therapy.

When 10 μM reserpine was added to ACNU in culture, the concentration of drug required for 50% inhibition of cell growth (IC50) of ACNU for C6/ACNU cells decreased to the level of that for C6 cells. When 20 μM reserpine was added to the culture, intracellular uptake of ACNU in C6/ACNU cells increased further and the efflux of the drug from the cells decreased. In in vivo experiments in rats, combined chemotherapy with ACNU (1 mg/kg) and reserpine (250 μg/kg) by intrathecal injection significantly increased the life span of the rats as compared to results with ACNU chemotherapy alone. The enhanced cytotoxicity of ACNU in ACNU-resistant glioma cells in vitro and in vivo may be explained by the increase of intracellular concentration of ACNU resulting from the inhibition of ACNU efflux from the resistant cells by reserpine. It was concluded that ACNU resistance could be modulated in vitro and in vivo by combined therapy with ACNU and reserpine.
Monitoring retraction pressure on the brain
Authors: Hongo Kazuhiro , Kobayashi Shigeaki , Yokoh Akira , Sugita Kenichiro
Published: May 2009

✓ The problem of minimizing tissue damage during brain retraction was studied both experimentally in dogs and clinically with the aid of newly designed strain-gauge retractor. The pressure required to obtain a specific exposure decreased gradually with time. The average time for a 50% reduction in retraction pressure was 6.6 minutes in the earlier trials of repeated retraction. The attenuation rate of retraction pressure gradually decreased when retraction of the same area was repeated. The lower the head position of the dog, the larger was the amplitude of brain retraction pressure. Clinical studies demonstrated that: 1) cerebrospinal fluid drainage was effective in decreasing the retraction pressure required; 2) use of multiple retractors reduced the pressure applied by each retractor; and 3) retraction pressure could be monitored when the strain-gauge retractors were applied to arteries and cranial nerves.
Vertebral arteriovenous fistula following anterior cervical spine surgery
Authors: Cosgrove G. Rees , Théron Jacques
Published: May 2009

✓ Fistulous communication between the vertebral artery and its surrounding venous plexus is rare. Two cases of vertebral arteriovenous fistula following anterior cervical spine surgery are reported. The anatomic relationships of the vertebral vessels, the radiographic findings, and the various therapeutic approaches to these lesions are discussed.
Mixed germ-cell tumor of the pineal region
Authors: Graziano Stephen L. , Paolozzi Frank P. , Rudolph Alfred R. , Stewart William A. , Elbadawi Ahmad , Comis Robert L.
Published: May 2009

✓ The case is presented of a 15-year-old boy with a mixed nongerminomatous germ-cell tumor of the pineal region associated with elevated cerebrospinal fluid and serum levels of the beta subunit of human chorionic gonadotropin. Treatment consisted of initial subtotal resection followed by radiotherapy and systemic chemotherapy with cisplatin, vinblastine, and bleomycin. The patient is alive without evidence of tumor 37 months after his initial diagnosis. A literature review of intracranial embryonal carcinoma and choriocarcinoma provided the rationale for a combined-modality approach to this otherwise lethal neoplasm.
Thoracic spinal canal stenosis
Authors: Barnett Gene H. , Hardy Russell W. , Little John R. , Bay Janet W. , Sypert George W.
Published: May 2009

✓ Hypertrophy of the posterior spinal elements leading to compromise of the spinal canal and its neural elements is a well-recognized pathological entity affecting the lumbar or cervical spine. Such stenosis of the thoracic spine in the absence of a generalized rheumatological, metabolic, or orthopedic disorder, or a history of trauma is generally considered to be rare. Over a 2-year period the authors have treated six cases of thoracic myelopathy associated with thoracic canal stenosis. In four patients the deficits developed gradually and painlessly. The three older patients had a clinical profile characterized by complaints of pseudoclaudication, spastic lower limbs, and evidence of posterior column dysfunction. Two patients were younger adults with low thoracic myelopathy associated with local back pain after minor trauma. Both patients also had congenital narrowing of the thoracic spinal canal.

Oil and metrizamide contrast myelography in the prone position were of limited value in diagnosing this condition; in fact, myelography may be misleading and result in erroneous diagnosis of thoracic disc protrusion, when the principal problem is dorsal and lateral compression from hypertrophied facets. Magnetic resonance imaging and computerized tomography sector scanning were more useful in the diagnosis of this disorder than was myelography. Thoracic canal stenosis may be more common than is currently recognized and account for a portion of the failures in anterior and lateral decompression of thoracic disc herniations.
Influence of modes of ACNU administration on tissue and blood drug concentration in malignant brain tumors
Authors: Hori Tomokatsu , Muraoka Kiyoaki , Saito Yoshikazu , Sasahara Kunihiro , Inagaki Hirotaka , Inoue Yukiya , Adachi Shigeru , Anno Yuichi
Published: May 2009

✓ The water-soluble nitrosourea compound ACNU is also lipid-soluble at normal physiological pH levels. It lacks toxic effects on vision that nitrosoureas occasionally produce following intra-arterial administration. In 28 cases of both primary and secondary malignant brain tumors, ACNU was administered at surgery or angiography by three different modes: intravenous injection in Group I (10 cases), intra-arterial injection via the carotid artery in Group II (11 cases), and intra-arterial injection via the carotid artery after opening the blood-brain barrier (BBB) by means of mannitol in Group III (seven cases). Tumor tissue and blood samples were taken serially at various time intervals after ACNU injection, and ACNU was measured by high-performance liquid chromatography. The time-concentration curve for ACNU was calculated in each case by the two- and one-compartment open models for determination of ACNU levels in blood and tissue, respectively. Pharmacokinetic parameters including biological half-life, blood and tissue levels (0-t minutes and 0-∞ minutes), total plasma clearance, and distribution volume of the β phase were compared. Statistical analysis of tissue ACNU levels at 0-t minutes revealed higher concentrations in Group III patients than in Groups II and I: levels in Group II were significantly higher than in Group I. Mean biological half-life was 30.3, 23.0, and 38.5 minutes in Groups I, II, and III, respectively. Levels of ACNU were significantly increased in tumor tissue as well as in peritumoral tissue in one Group III patient with multiple metastatic anaplastic adenocarcinoma. In this series, treatment of malignant brain tumor by intra-arterial administration of ACNU produced significantly higher tissue levels of ACNU than did the systemic intravenous route.
Physiological and metabolic response to isolated closed-head injury
Authors: Deutschman Clifford Scott , Konstantinides Frank N. , Raup Sandra , Cerra Frank B.
Published: May 2009

✓ In order to determine the effects of steroid administration on the metabolic response to isolated closed-head injury, a longitudinal study was performed. Metabolic indices were prospectively evaluated for the first 5 days postinjury in six patients who received steroids and 10 patients who did not. Patients were carefully screened to eliminate those with associated injuries as well as those with abnormalities due to sepsis. Other than steroid administration, a uniform treatment regimen was used in both groups. Metabolic indices measured on postinjury Days 1, 3, and 5 were analyzed. In addition, data were compared to results in large data banks obtained both from overnight-fasted patients (fasted controls) and from polytrauma victims (stressed controls). Both treatment groups were comparable with respect to age, mean Glasgow Coma Scale scores on admission and on Day 5, and initial intracranial pressure. Metabolic data indicated significantly higher levels of nitrogen excretion and somatic protein mobilization in steroid-treated patients than in patients not receiving steroids. In both groups, glucose levels, the lactate/pyruvate ratio, and branched-chain amino acid levels (all metabolic indices that correlate well with level of stress) initially corresponded to values for stressed controls. By Day 5, values for these variables were similar to fasted controls for the group not receiving steroids. In patients receiving steroids, however, the data remained similar to those for stressed controls. It is concluded that steroids prolong the metabolic abnormalities associated with the initial phase of head injury. In view of inconclusive data regarding benefit from steroid administration, serious questions must be raised regarding the use of these catabolic agents in this setting.
The shaken baby syndrome
Authors: Duhaime Ann-Christine , Gennarelli Thomas A. , Thibault Lawrence E. , Bruce Derek A. , Margulies Susan S. , Wiser Randall
Published: May 2009

✓ Because a history of shaking is often lacking in the so-called “shaken baby syndrome,” diagnosis is usually based on a constellation of clinical and radiographic findings. Forty-eight cases of infants and young children with this diagnosis seen between 1978 and 1985 at the Children's Hospital of Philadelphia were reviewed. All patients had a presenting history thought to be suspicious for child abuse, and either retinal hemorrhages with subdural or subarachnoid hemorrhages or a computerized tomography scan showing subdural or subarachnoid hemorrhages with interhemispheric blood. The physical examination and presence of associated trauma were analyzed; autopsy findings for the 13 fatalities were reviewed. All fatal cases had signs of blunt impact to the head, although in more than half of them these findings were noted only at autopsy. All deaths were associated with uncontrollably increased intracranial pressure.

Models of 1-month-old infants with various neck and skull parameters were instrumented with accelerometers and shaken and impacted against padded or unpadded surfaces. Angular accelerations for shakes were smaller than those for impacts by a factor of 50. All shakes fell below injury thresholds established for subhuman primates scaled for the same brain mass, while impacts spanned concussion, subdural hematoma, and diffuse axonal injury ranges. It was concluded that severe head injuries commonly diagnosed as shaking injuries require impact to occur and that shaking alone in an otherwise normal baby is unlikely to cause the shaken baby syndrome.
Effect of a calcium channel blocker on posttraumatic spinal cord blood flow
Authors: Guha Abhijit , Tator Charles H. , Piper Ian
Published: May 2009

✓ The normal rat spinal cord blood flow (SCBF) has been shown to increase after administration of nimodipine, a calcium channel blocker. The present study investigates the capability of nimodipine to improve SCBF, as measured by the hydrogen clearance technique, after a 53.0-gm clip compression injury to the T-1 segment of the rat spinal cord.

The profound drop in mean systemic arterial blood pressure (MSAP) after cervical cord injury precluded any improvement in posttraumatic SCBF by nimodipine alone. Hence, in a randomized controlled study with five rats per group, pressor agents (whole blood, angiotensin, or adrenaline) were infused to maintain MSAP between 100 and 120 mm Hg after injury. Control animals received only a saline infusion. Nimodipine at the optimal dose found in normal animals (1.5 µg/kg/min) was added to the pressor agents. The MSAP and other physiological parameters were measured in rats receiving the pressor agents only and in those receiving pressor agents combined with nimodipine.

In rats receiving whole blood, angiotensin, or adrenaline the posttraumatic MSAP improved to between 100 and 120 mm Hg, but there was no improvement in SCBF compared to the saline group. The addition of nimodipine decreased MSAP and SCBF in all groups except those animals also receiving adrenaline, where the MSAP was maintained at 109 ± 5 mm Hg. In these animals a significant increase in posttraumatic SCBF from 16.5 ± 2.1 to 20.2 ± 2.3 ml/100 gm/min (mean ± standard error of the mean) occurred at the site of injury with the addition of nimodipine.

The maintenance of an adequate MSAP by a pressor agent was crucial for nimodipine to improve posttraumatic SCBF by its ability to dilate the spinal vascular bed. Adrenalin was the only pressor agent that could fulfill the above criteria, although other pressor agents need to be investigated. Experiments are underway with the combination of adrenaline and nimodipine to further verify these encouraging results demonstrating an improvement in posttraumatic ischemia of the spinal cord.
Microangioarchitecture of the feline spinal cord
Authors: Naka Yutaka , Itakura Toru , Nakai Kunio , Nakakita Kazuo , Imai Harumichi , Okuno Takashi , Kamei Ichiro , Komai Norihiko
Published: May 2009

✓ The microangioarchitecture of corrosion casts of the cat spinal cord was studied by scanning electron microscopy. On the ventral surface of the spinal cord, the anterior spinal artery and the anterior spinal vein ran parallel along the anterior median fissure. Many central arteries branching from the anterior spinal artery coursed in a wavelike manner in the anterior median fissure. The number of central arteries was lowest in the thoracic spinal cord. Central arteries at some spinal cord levels revealed well-developed anastomoses with other central arteries in the anterior median fissure. These well-developed anastomotic central arteries were frequently observed in the thoracic spinal cord, in which the number of central arteries was lowest. On the dorsal surface of the spinal cord, the posterior spinal vein ran longitudinally at the midline and was drained by circumferential veins and posterior central veins. This vein formed a characteristic anastomotic plexus. Small arterioles (20 µm in diameter) in the spinal parenchyma revealed a ring-like compression at the branching site.
Multiple intracranial aneurysms due to Coccidioides immitis infection
Authors: Hadley Mark N. , Martin Neil A. , Spetzler Robert F. , Johnson Peter C.
Published: May 2009

✓ True mycotic (fungal) aneurysms are distinctly uncommon. The case of a young woman with multiple intracranial aneurysms of Coccidioides immitis origin is presented. Coccidioides immitis organisms are not uncommon central nervous system pathogens and usually cause basilar meningitis and hydrocephalus. There are no previous reports of a coccidioidal mycotic aneurysm. The management of intracranial coccidioidomycosis and fungal aneurysms is reviewed.
Spontaneous carotid-cavernous fistula and multiple arterial dissections in Type IV Ehlers-Danlos syndrome
Authors: Lach Boleslaw , Nair Sreelatha G. , Russell Neville A. , Benoit Brien G.
Published: May 2009

✓ A 43-year-old woman without phenotypic expression of Ehlers-Danlos syndrome developed a spontaneous unilateral carotid-cavernous fistula (CCF). Attempts at balloon occlusion of the CCF were unsuccessful, and caused multiple arterial dissections and lacerations eventually leading to massive retroperitoneal hemorrhage and death. The CCF was demonstrated during postmortem studies. In addition, the patient had independent dissections of the internal carotid artery at the site of the fistula and an intracavernous aneurysm of the contralateral internal carotid artery. Despite widespread dissections, the major arteries showed only mild histological abnormalities. Morphometric analysis of collagen from the aorta revealed an increase in largesized fibers, consistent with deficiency of Type III collagen.
Reconstruction of cerebral cortical veins using silicone tubing
Authors: Sakaki Toshisuke , Morimoto Tetsuya , Takemura Kiyoshi , Miyamoto Seiji , Kyoi Kikuo , Utsumi Shozaburo
Published: May 2009

✓ A technique for reconstruction of a cerebral cortical vein which has been sacrificed during an interhemispheric or subtemporal surgical approach is described. The method involves the use of silicone tubing. The author's clinical experience in six patients is summarized.
CT localization of a convexity brain tumor on the scalp
Authors: Penning Lourens
Published: May 2009

✓ Preoperative localization of a tumor on the scalp can be achieved with the help of computerized tomography (CT) but is liable to error. A simple method is presented to relate the data provided by the CT scan precisely to the scalp of the patient.
Aneurysms of the basilar artery trunk
Authors: Sugita Kenichiro , Kobayashi Shigeaki , Takemae Toshiki , Tada Tsuyoshi , Tanaka Yuichiro
Published: May 2009

✓ Ten cases of basilar artery trunk aneurysms are reported; nine were operated on by a middle subtemporal approach and one by a pterional transsylvian technique. The middle subtemporal approach facilitated clipping of aneurysms located as deep as 25 mm below the posterior clinoid process as seen on the lateral views of the angiogram, such that the junction of the vertebral arteries was visible in most cases. The authors emphasize the usefulness of direct retraction of the trigeminal nerve, the pons, and the aneurysm itself; occasionally, drilling off the pyrimidal edge is also valuable. Surgical results were satisfactory in seven cases and poor in one; two patients died.
Management of simple depressed skull fractures in children
Authors: Steinbok Paul , Flodmark Olof , Martens Diana , Germann Eva T.
Published: May 2009

✓ Surgical elevation is the treatment usually recommended for a simple depressed skull fracture if the depression is more than the full thickness of the adjacent skull, but there is no clinical evidence to support this management. On that basis, a progressively more conservative approach to the treatment of this condition was adopted, especially in young children. Experience with this mode of management over the period 1972 to 1984 is presented. Of 111 patients under 16 years of age with depressed skull fractures, 64 had simple and 47 compound fractures. Simple depressed skull fractures occurred in a younger age group after less significant trauma than compound fractures. In those patients who were treated surgically, there was an 11% incidence of dural laceration in patients with simple depressed fractures versus 67% for the patients with compound depressed fractures. There was no difference in outcome between surgically and nonsurgically treated patients with simple depressed fractures with respect to the occurrence of seizures, neurological dysfunction, or cosmetic appearance. Surgical treatment prolonged hospitalization, and the only case with a fatal outcome was found in the group of patients treated surgically. It is suggested that the standard treatment of simple depressed skull fractures in the pediatric age group should not include surgery. Surgery is indicated when there is definite evidence of dural penetration and in the older child with an unacceptable cosmetic appearance.
Familial intracranial aneurysms
Authors: Lozano Andrés M. , Leblanc Richard
Published: May 2009

✓ The authors report seven individuals from two families, all of whom had aneurysmal subarachnoid hemorrhage. These cases and all reported cases of familial aneurysms (243 aneurysms in 177 patients from 74 families) were submitted to computer-aided multivariate analysis to determine if the aneurysms or the patients who harbor them differ from sporadic aneurysm cases. Familial aneurysms rupture at a smaller size (mean diameter 10.5 mm), and when the patient is younger (mean age 42.3 years and decennial age at peak incidence 40 to 49 years). There is a similar sex distribution (male to female ratio 48:52), a similar incidence of multiple aneurysms (21.5%), and a similar predominance of females over males with multiple aneurysms (2.2:1). Anterior communicating artery aneurysms occur less often in familial cases (19%) than in sporadic cases. In sibling pairs the aneurysms occur at the same or at mirror sites, and rupture within the same decade twice as frequently as randomly selected nonfamilial aneurysm patient pairs. The occurrence of aneurysms at identical and mirror sites is more frequent in familial cases and appears to be a function of the degree of kinship between affected individuals. These observations suggest a genetic basis for the pathogenesis of familial intracranial aneurysms.
Cerebral arteriovenous malformations, steal, and the hypertensive breakthrough threshold
Authors: Morgan Michael K. , Johnston Ian , Besser Michael , Baines David
Published: May 2009

✓ An experiment was designed to investigate the effects of arteriovenous (AV) fistula occlusion on cerebral autoregulation. A right carotid-jugular fistula was created in 63 rats in such a way as to produce an intracranial AV fistula with a loop extension into the neck. The fistula was occluded after an 8-week interval with the rats under both normotension and metaraminol-induced hypertension, and evidence of blood-brain barrier disruption was investigated with an Evans blue dye technique. The results indicate that an intracranial AV fistula may cause cerebral steal which is responsible for a reduction in the threshold for hypertensive breakthrough following fistula occlusion.
Experimental intracerebral hemorrhage: effects of a temporary mass lesion
Authors: Sinar E. J. , Mendelow A. David , Graham David I. , Teasdale Graham M.
Published: May 2009

✓ Late pathophysiological events after the production and subsequent removal of an intracerebral mass were investigated using a mechanical microballoon model to simulate intracerebral hemorrhage. Immediately following balloon inflation in the caudate nucleus of rats, there was a significant increase in intracranial pressure to 14 ± 1 mm Hg (mean ± standard error of the mean), accompanied by a reduction in cerebral blood flow (CBF) in the ipsilateral frontal cortex, as measured by the hydrogen-clearance technique. Carbon-14-iodoantipyrine autoradiography revealed a significant reduction in the CBF of the ipsilateral caudate nucleus 4 hours after balloon inflation: 31% of the caudate nucleus had a CBF of less than 20 ml ⋅ 100 gm−1 ⋅ min−1 compared to only 1% in the sham-treated control group (balloon insertion without inflation). The rats with an intracerebral mass exhibited a significant increase in the volume of ischemic damage in the ipsilateral caudate nucleus (17.1% of total volume) compared to only 1.7% in the sham-treated group; however, there was no evidence of cerebral edema. Ischemic damage and reduced CBF persisted for 4 hours after transient inflation of a microballoon in the caudate nucleus. This suggests that ischemic damage occurs at the time of formation of the lesion and is not prevented by its early removal.
Influence of the rate of ventricular enlargement on the white matter water content in progressive feline hydrocephalus
Authors: Takei Futoshi , Shapiro Kenneth , Kohn Ira
Published: May 2009

✓ The effectiveness of transependymal absorption of cerebrospinal fluid in hydrocephalus was studied by correlating the measured water content of feline hydrocephalic white matter with the rate of enlargement of the ventricles. Two groups of cats were subjected to opening of either the calvaria or the calvaria and dura before the intracisternal injection of kaolin to obtain two profiles of ventricular enlargement. The water content 1, 2, and 3 mm from the lateral ventricles was measured in each group using the dry/wet weight and microgravimetric techniques after sacrificing the animals in each group at 2, 3, or 6 weeks after inducing hydrocephalus.

In the animals with both calvarial and dural opening, the ventricles enlarged rapidly in the first 2 to 3 weeks and then continued to increase but at a slower rate. Concomitant with this early increase of ventricular size was a progressive increase in white matter water content both adjacent to and remote from the ventricles, which continued through 6 weeks. When only the calvaria was opened, ventricular size increased gradually, but continued to increase at a constant rate throughout the 6 weeks. Water content adjacent to the ventricle did not increase until the 3rd week, with little spread to adjacent areas by the 6th week. The central canals of the spinal cord were enlarged in both groups at all sampling levels.

Neither increased periventricular water nor dilatation of the central canal was associated with stabilization of ventricular size in these studies. The authors conclude that these pathways are not sufficient to arrest the hydrocephalic process in these models.
Cerebral endometriosis
Authors: Thibodeau Lee L. , Prioleau George R. , Manuelidis Elias E. , Merino Maria J. , Heafner Michael D.
Published: May 2009

✓ A 20-year-old woman presented with a 3-year history of intermittent focal headaches and a generalized seizure. Computerized tomography demonstrated a hypodense ring-enhancing cystic right parietal lobe lesion. At operation, a chocolate-colored cyst was excised which on histological examination proved to be endometriosis.
Syringomyelia as a complication of Paget's disease
Authors: Elisevich Kost , Fontaine Suzanne , Bertrand Gilles
Published: May 2009

✓ Cranial settling and basilar invagination with medullospinal compression is believed to have resulted in the production of a syrinx in a case of Paget's disease of the cranium. This mechanism of compression at the craniovertebral junction resembles the development of syringomyelia in Chiari malformations presenting in adult life.
Intracranial metastases from malignant spinal-cord astrocytoma
Authors: Johnson Dennis L. , Schwarz Saul
Published: May 2009

✓ A patient with postoperative intracranial seeding from a malignant spinal-cord astrocytoma is presented. This case is compared with 17 previously cited cases of intracranial dissemination from spinal-cord astrocytoma. Factors associated with tumor dissemination include histological malignancy, proximity of the tumor to cerebrospinal fluid (CSF) pathways, and surgical manipulation. Hydrocephalus with infiltration of the basal cisterns also appears to be a consistent feature in these patients. Cytological studies of the CSF in this and previous cases were noted to be misleading, whereas intravenous contrast-enhanced cranial computerized tomography was invaluable for diagnosis of tumor dissemination in each case. Prophylactic irradiation of the entire neuraxis may limit intracranial metastases from malignant astrocytomas of the spinal cord.
A new fixation device for the Leksell stereotaxic system
Authors: Leksell Lars , Lindquist Christer , Adler John R. , Leksell Dan , Jernberg Bengt , Steiner Ladislau
Published: May 2009

✓ A device is presented that permits several applications for the Leksell stereotaxic system. The patient is fixed in this new system by means of a rectangular instrument that connects to the standard Leksell stereotaxic coordinate frame and maintains spatial orientation after the frame itself is removed. Specific uses for this device include stereotaxic radiosurgery and stereotaxic guidance during microsurgery. Other attractive features of this device are its capability of being precisely reapplied, its compatibility with both computerized tomography and magnetic resonance imaging, and the availability of an accessory device to adapt it for animal stereotaxis.
Vertebrobasilar insufficiency
Authors: Hopkins Leo N. , Martin Neil A. , Hadley Mark N. , Spetzler Robert F. , Budny James , Carter L. Philip
Published: May 2009

✓ Posterior circulation transient ischemic attacks have an associated risk of subsequent infarction of approximately 5% per year. Intracranial vertebrobasilar thrombo-occlusive lesions appear particularly likely to result in repetitive ischemic symptoms and in infarction due to hemodynamic insufficiency. The authors present their experience with 45 patients with symptomatic intracranial vertebrobasilar vascular disease despite maximal medical therapy. The specific operative approaches for intracranial vertebral artery endarterectomy and extracranial to intracranial posterior circulation revascularization procedures are outlined.
Hydrocephalus secondary to cysticercotic arachnoiditis
Authors: Sotelo Julio , Marin Cora
Published: May 2009

✓ Ninety-two patients with hydrocephalus secondary to cysticercotic meningitis were followed for a mean period of 8 years 11 months. The mortality rate was 50%, with most patients dying within the first 2 years after cerebrospinal fluid (CSF) shunting. The prognosis was worse in females than in males. Multiple surgical procedures for shunt obstruction were necessary in half of the patients. Complications such as bacterial meningitis and shunt obstruction were more frequent in the patients who died than in those who survived. The follow-up data revealed that the clinical status was satisfactory in 78% of survivors and unsatisfactory in 22%. Spontaneous remission of the cysticercotic arachnoiditis, as shown by the CSF findings, occurred in only 18% of the cases. In most patients, arachnoiditis and positive immune reactions persisted unchanged even after several years. The results demonstrate the poor outcome of these patients and indicate the need for better medical and surgical therapy.
The neurological and skeletal outcome in patients with closed cervical spinal cord injury
Authors: Donovan William H. , Kopaniky Dennis , Stolzmann Eweline , Carter R. Edward
Published: May 2009

✓ Sixty-one patients with closed cervical spinal cord injury were cared for within a defined protocol and followed for at least 1 year. Neurological recovery and healing of spinal structures were evaluated at intervals. Forty-three patients were managed without surgical intervention at the site of spine trauma, and the incidence of spontaneous fusion (”autofusion”) was noted. Surgical fusion was performed on 17 patients, mainly to restore spinal stability and alignment. One patient underwent laminectomy without fusion. In both the surgical fusion and the autofusion groups, there were significant numbers of patients who improved neurologically, including some designated as having a complete spinal cord lesion at the initial neurological examination. As expected, better spinal alignment was achieved in the surgical group, although alignment in the nonsurgically treated group was generally acceptable. The majority of patients developed radiographically apparent callus formation anterior to the injured vertebral bodies, regardless of the mechanism of injury or the method of treatment. After 3 months all patients who underwent surgical fusion achieved spinal stability, as did the majority of patients in the autofusion group. Only individuals with flexion-distraction injuries who did not undergo surgical fusion appeared to be at risk for progressive spinal column deformity. Neither retropulsion of bone fragments nor angulation at the fracture site appeared to correlate with a poor neurological outcome, since improvement in neurological function occurred similarly in patients with and without these deformities.
Magnetic resonance imaging of spinal meningiomas and neurinomas
Authors: Schroth Gerhard , Thron Armin , Guhl Lothar , Voigt Karsten , Niendorf Hans-Peter , Garces Luis Rios-Nogales
Published: May 2009

The detection and delineation of spinal tumors by magnetic resonance imaging (MRI) after intravenous administration of gadolinium (Gd)-diethylenetriaminepenta-acetic acid (DTPA) is demonstrated in eight cases of neurinoma or meningioma. The advantages of Gd-DTPA-enhanced MRI over other MRI techniques used in more than 100 cases of spinal cord diseases are described.
Time course of blood velocity changes related to vasospasm in the circle of Willis measured by transcranial Doppler ultrasound
Authors: Harders Albrecht G. , Gilsbach Joachim M.
Published: May 2009

✓ Fifty patients with ruptured aneurysms were operated on within 72 hours after the first subarachnoid hemorrhage (SAH). To prevent symptomatic vasospasm, the patients were given the calcium channel blocker, nimodipine, intravenously (2 mg/hr) for 14 days and orally (60 mg four times daily) for another 7 days. At short intervals (at least every 3rd day) the blood flow velocity in the different segments of the circle of Willis was measured with a noninvasive transcranial Doppler ultrasonography method. Within the first 72 hours after SAH, the velocity was normal in the large branches of the circle of Willis and angiography revealed no signs of vasospasm. The Doppler frequency changes that relate to blood flow accelerated between Days 3 and 10, and maximum blood flow velocities were recorded between Days 11 and 20, with normalization occurring within the following 4 weeks. The changes showed a significant relationship to the source of SAH, the side of the operative approach, and the method of nimodipine administration. A comparison between the angiographically proven diameter of spastic arteries and the Doppler-measured blood flow velocity showed an inverse relationship in flow of the middle cerebral artery and the internal carotid artery that was statistically highly significant (p < 0.001) while this correlation was only slightly significant in the A1 segment of the anterior cerebral artery (p = 0.054). Seven patients (14%) developed delayed ischemic deficits (DID's), which were all functionally reversible. One patient (2%) died as a result of decompensated vasospasm. Based on the information provided by Doppler measurement of the individual blood flow velocity changes due to vasospasm, preventive hypertensive treatment was introduced to improve the perfusion pressure while patients were still in an asymptomatic stage. Among the last 40 patients who were treated according to this regimen, reversible DID's were observed in only three patients (7.5%) and postoperative angiography to detect vasospasm was not necessary.
Correlation of tumor plasminogen activator with peritumoral cerebral edema
Authors: Quindlen Eugene A. , Bucher Anita P.
Published: May 2009

✓ Extracts from 15 human cerebral tumors were tested by a fibrin-plate plasminogen-dependent assay for levels of tumor plasminogen activator (TPA) activity. The TPA activity was correlated with the amount of perineoplastic edema as quantified on computerized tomography (CT) brain scanning. Analysis of the results showed a correlation coefficient of 0.72 when all tumors were included. Analysis of the nine tumors with the highest TPA levels showed a correlation coefficient of 0.96. One metastatic tumor had the highest level of TPA activity, equivalent to a pure 100-µg/ml solution of urokinase, and the greatest amount of cerebral edema on CT. Meningiomas generally had the next highest levels of TPA activity and edema, followed by astrocytomas of varying grades, which generally had the lowest level of TPA activity. However, three astrocytomas that had low TPA activity also had significant edema surrounding the tumor, indicating that more than one mechanism may be producing peritumoral edema. There was no correlation between tumor size and the amount of perineoplastic edema. These preliminary results suggest that TPA's may be involved in the production of perineoplastic cerebral edema and that treatment of patients with currently available plasminogen activator inhibitors may be successful in reducing peritumoral edema.
A laboratory model of shunt-dependent hydrocephalus
Authors: Fried Arno , Shapiro Kenneth , Takei Futoshi , Kohn Ira
Published: May 2009

✓ This study was designed to determine whether implanting shunts in hydrocephalic cats produced the same biomechanical changes as have previously been found in children with shunts. Neuraxis volume-buffering capacity (pressure-volume index: PVI) and the resistance to the absorption of cerebrospinal fluid (CSF) were determined before and 3 weeks after placing shunts in 16 hydrocephalic cats. Intracranial pressure (ICP) was monitored for at least 6 hours after the shunts were occluded. The brains were perfused in vivo and removed to assess the size of the ventricles.

The mean PVI of the hydrocephalic cats was 3.6 ± 0.2 ml (± standard error of the mean) before the shunts were placed. Three weeks after adequate shunt function was first established, the mean PVI decreased to 1.1 ± 0.1 ml and was similar to values determined in control animals. Prior to shunt placement, the resistance to the absorption of CSF was 28.4 ± 4.5 mm Hg/ml/min and did not vary with ICP. This parameter changed after shunting and increased as a function of ICP (r = 0.87, p < 0.001). At ICP's below 20 mm Hg, the resistance to the absorption of CSF was 65.0 ± 18.0 mm Hg/ml/min but increased to 220.0 ± 40.5 mm Hg/ml/min when determined at ICP's above 20 mm Hg. Corroborating evidence for this linkage of resistance to the absorption of CSF to ICP was found in the inexorable rise of ICP during the 6 hours of monitoring after the shunts were occluded. After shunt placement, the ventricles were normal in size in 12 cats and slightly enlarged in four.

The biomechanical profile and pressure response to shunt occlusion in this laboratory model resembles that previously described in shunt-dependent children. As in humans, shunt placement in hydrocephalic cats results in normalization of the PVI and a linkage of the resistance to the absorption of CSF to ICP. The significance of these changes as they relate to shunt dependency is discussed.
Argon laser-induced arterial photothrombosis
Authors: Watson Brant D. , Dietrich W. Dalton , Prado Ricardo , Ginsberg Myron D.
Published: May 2009

✓ The common carotid, femoral, and middle cerebral arteries in the rat have been occluded thrombotically by means of a rose bengal dye-sensitized photochemical reaction initiated in vascular endothelium by the 514.5-nm beam of an argon laser, focused for maximum excitation efficiency of the photosensitizer according to a derived criterion. The total energy required for vessel occlusion was approximately 1 joule (J) for the middle cerebral artery and 140 to 180 J for the femoral and carotid arteries. At energy fluences (energy deposited per unit area) of 3.5 kJ/sq cm for the middle cerebral artery and 35 kJ/sq cm for the larger arteries, occlusion was observed within 3 minutes. The middle cerebral artery thrombus consisted entirely of aggregated platelets; in the larger arteries the thrombi were composed of platelet aggregates and groups of red blood cells interspersed within a matrix of coagulum. Vessels irradiated similarly in the absence of rose bengal dye displayed no morphological or functional damage. Because the photochemical reaction is mediated by electronic-state transitions, the process of photothrombosis (as opposed to photocoagulation) can be initiated in vessels with high flow rates without the requirement of increased temperature. The photothrombotic technique may be useful in the treatment of arteriovenous malformations owing to its significant enhancement of the efficiency and permanency of vessel occlusion.
The hemodynamic effects of internal carotid artery stenosis and occlusion
Authors: Mendelow A. David , Graham David I. , Tuor Ursula I. , Fitch William
Published: May 2009

✓ The purpose of this study was to determine in subhuman primates whether hemodynamic mechanisms (as compared with embolic mechanisms) contribute to cerebral ischemia following carotid artery occlusion or stenosis. Following carotid artery occlusion there was loss of cerebral autoregulation: cerebral blood flow (CBF) measured with the xenon-133 technique became passively dependent upon the mean arterial blood pressure (MABP) over an MABP range of 30 to 110 mm Hg. By contrast, autoregulation was preserved in normal animals and in animals with a 90% carotid artery stenosis. Regional CBF was measured with carbon-14-labeled iodoantipyrine autoradiography in normotensive baboons, in hypotensive animals, and in hypotensive animals with carotid artery occlusion or stenosis. With carotid artery occlusion and hypotension, reduced levels of local CBF were seen ipsilaterally in the boundary zones between the anterior and middle cerebral arteries with 35% of the area of an anterior section through the hemisphere displaying a CBF value of less than 20 ml/100 gm/min. Comparable values with hypotension were 21% with carotid artery stenosis, 20% with no proximal vascular lesion, and 1% in normotensive animals. These areas of reduced CBF corresponded with areas of boundary-zone ischemia seen with light microscopy. The study suggests that while hemodynamic ischemia develops with carotid artery occlusion, it does not occur with even a 90% carotid artery stenosis or in normal animals.