bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the risks of anticoagulation therapy following experimental craniotomy in the rat
Authors: Schaible Keith L. , Smith Lawrence J. , Fessler Richard G. , Rachlin Jacob R. , Brown Frederick D. , Mullan Sean
Published: May 2009

✓ The risk of hemorrhagic complications with anticoagulation therapy in patients following intracranial surgery has prevented investigation of the potential use of heparin in the early postoperative period. The authors have evaluated the safety of anticoagulation therapy following experimental craniotomy in male Holtzman rats. The dose and schedule of heparin administration, which elevated and maintained the activated partial thromboplastin time (APTT) within the therapeutic range of 15 to 3 × control APTT, was alternating doses of 400 and 500 IU/kg injected subcutaneously every 6 hours. This schedule was initiated 2, 4, 7, 10, and 14 days after craniotomy and was continued for 72 hours thereafter. The results demonstrated that the incidence of intracerebral hemorrhage declined as the postoperative interval prior to initiation of anticoagulation increased. If anticoagulation therapy was initiated during the first 7 postoperative days, the risk of intracerebral hemorrhage was high (mean 14.7%); however, if an additional 3 to 7 days elapsed prior to initiation of anticoagulation, the incidence of intracerebral hemorrhage dropped significantly (mean 0%) (p < 0.05). These results suggest that anticoagulation therapy can be safely initiated 10 to 14 days after craniotomy.
Diagnosis of subdural hemorrhage in utero
Authors: Hanigan William C. , Ali Maqbool B. , Cusack Thomas J. , Miller Tim C. , Shah Jitendra J.
Published: May 2009

✓ A case is presented of subdural hemorrhage diagnosed in utero at 31 weeks of gestation by fetal ultrasonography. Following delivery, clinical examination of the infant revealed hydrops fetalis, right-sided cardiomegaly, hepatic dysfunction, and coagulopathy. Prompt resolution of these problems led to a retrospective diagnosis of premature closure of the foramen ovale as the precipitating event. The causes of previously reported cases of intrauterine cerebral hemorrhage are reviewed and compared to the present case.
Biocompatibility analysis of the Sundt-Kees booster clip and the Drake aneurysm clip
Authors: Anderson Robert E. , Bowron Alice M. , Sundt Thoralf M.
Published: May 2009

✓ A combination of the Sundt-Kees reinforcing aneurysm clip applied to a Drake aneurysm clip in a piggyback fashion was studied for possible defects due to corrosion and or tissue toxicity. These two clips, which are made of similar metal (301 stainless steel), showed little or no defects when immersed in 5% saline or when implanted in rats for 6 months. This study demonstrates that clips made of similar metals can be used piggyback in patients without ill effects provided that they are carefully handled to avoid any abrasion or misbends which could conceivably lead to corrosion.
Diagnosis and surgical treatment of disabling positional vertigo
Authors: Møller Margareta B. , Møller Aage R. , Jannetta Peter J. , Sekhar Laligam
Published: May 2009

✓ This report reviews the characteristic symptoms of disabling positional vertigo (DPV), and the tests used to reach a differential diagnosis of this disorder. Twenty-one patients were operated on consecutively for management of DPV between March, 1983, and September, 1984. In all patients one or more arteries or veins was found to be compressing the eighth cranial nerve when the nerve was exposed for microvascular decompression to relieve the symptoms of DPV. After the operation, 16 of the 21 patients were free of symptoms, or symptoms were so much improved that the patients returned to normal work or social life. Two patients had no improvement and three had limited relief of symptoms postoperatively. None of the patients experienced hearing loss as a result of the operation to relieve DPV, but one patient suffered a cerebellar contusion during the operation.
Cystic meningiomas
Authors: Parisi Giuseppe , Tropea Rosario , Giuffrida Salvatore , Lombardo Maria , Giuffrè Francesco
Published: May 2009

✓ Seven patients with cystic meningioma are reported. The computerized tomography appearance of these meningiomas may mimic that of a glial or metastatic tumor with cystic or necrotic changes, and lead to an incorrect presumptive diagnosis. Radiological evaluation and recognition are important for the surgical removal of these potentially curable neoplasms.
Vascular and neural pathology of lumbosacral spinal stenosis
Authors: Watanabe Ryo , Parke Wesley W.
Published: May 2009

✓ During a study of the intrinsic vasculature of the lumbosacral spinal nerve roots in cadavers, a typical case of spinal stenosis was encountered. A review of the antemortem anamnesis revealed that this patient had had an intermittent claudication of the cauda equina. Investigation of the concomitant vascular and histopathological alterations of the affected nerve roots suggested that the claudication may have resulted from ectopic nerve impulse discharges elicited by rapid changes in the blood supply following exertion. The unexpectedly slight apparent neural deficit relative to observed root damage may be attributed to a neuronal plasticity within the spinal cord that permitted functional compensations to develop during the slow acquisition of the chronic nerve root pathology.
Treatment of experimental stroke with opiate antagonists
Authors: Baskin David S. , Hosobuchi Yoshio , Grevel Joachim C.
Published: May 2009

✓ The effects are reported of acute and long-term continuous administration of three opiate antagonists — naloxone, naltrexone, and diprenorphine — on neurological function, survival, and infarct size in a feline model of acute focal cerebral ischemia. All three drugs produced statistically significant improvement in motor function following acute administration without concomitant changes in level of consciousness; saline had no effect. Naloxone and naltrexone significantly prolonged survival (p < 0.01); diprenorphine did not. Infarct size was not altered by any treatment administered. These findings confirm previous work suggesting that, with the appropriate methodology, treatment with opiate antagonists partially reverses neurological deficits. They also show that opiate antagonists prolong survival in certain conditions of acute and subacute focal cerebral ischemia without altering the area of infarcted tissue.
Effects of rapid mannitol infusion on cerebral blood volume
Authors: Ravussin Patrick , Archer David P. , Tyler Jane L. , Meyer Ernst , Abou-Madi Mounir , Diksic Mirko , Yamamoto Lucas , Trop Davy
Published: May 2009

✓ Positron emission tomography was used to study the effect of a rapid infusion of mannitol on cerebral blood volume (CBV) in five dogs and in three human subjects. The ability of mannitol to reduce intracranial pressure (ICP) has always been attributed to its osmotic dehydrating effect. The effects of mannitol infusion include increased osmolality, total blood volume, central venous pressure (CVP), and cerebral blood flow, and decreased hematocrit, hemoglobin concentration, serum sodium level, and viscosity. Mannitol's ability to dilate the cerebral vasculature, either directly or indirectly, and thus to transiently increase ICP, is a subject of controversy. By in vivo labeling of red cells with carbon-11, the authors were able to demonstrate an early increase in CBV in dogs of 20%, 27%, and 23% (mean increase, p < 0.05) at 1, 2, and 3 minutes, respectively, after an infusion of 20% mannitol (2 gm/kg over a 3-minute period). The animals' muscle blood volume increased by 27% (mean increase, p < 0.05) 2 minutes after infusion. In the human subjects, lower doses and a longer duration of infusion (1 gm/kg over 4 minutes) resulted in an increase in CBV of 8%, 14% (p < 0.05), and 10% at 1, 2, and 3 minutes, respectively, after infusion. In dogs, ICP increased by 4 mm Hg (mean increase, p < 0.05) 1 minute after the infusion, before decreasing sharply. The ICP was not measured in the human subjects. Hematocrit, hemoglobin, sodium, potassium, osmolality, heart rate, mean arterial pressure (MAP), and CVP were measured serially. Results of these measurements, as well as the significant decrease in MAP that occurred after mannitol infusion, are discussed. This study demonstrated that rapid mannitol infusion increases CBV and ICP. The increase in muscle blood volume, in the presence of a decreased MAP and an adequate CVP, suggests that mannitol may have caused vasodilation in these experiments.
Large extra-abdominal cyst as a postpartum complication of peritoneal shunt
Authors: Nugent Philip , Hoshek Sylvio
Published: May 2009

✓ An extra-abdominal cyst filled with cerebrospinal fluid was found postpartum in a patient with a ventriculoperitoneal (VP) shunt. No similar complication of VP shunting has been reported before.
Outcome evaluation following subarachnoid hemorrhage
Authors: Säveland Hans , Sonesson Bengt , Ljunggren Bengt , Brandt Lennart , Uski Tore , Zygmunt Stefan , Hindfelt Bengt
Published: May 2009

✓ Seventy-eight individuals among a population of 1.46 million suffered aneurysmal subarachnoid hemorrhage (SAH) during 1983. Within 24 hours after the bleed, 32 of the 78 patients were in Hunt and Hess neurological Grades I to II, 13 were in Grade III, 21 were in Grades IV to V, and 12 were dead on admission to a hospital or forensic department. When the amount of blood visualized on computerized tomography (CT) scanning was integrated with the Hunt and Hess neurological classification in order to improve prediction of prognosis, only 16 patients were considered to have a good prognosis (CT-modified Grades I to II), 21 had a less favorable prognosis (CT-modified Grade III), and 29 had a poor prognosis (CT-modified Grades IV to V).

Assessment at 1 year revealed that only 32 patients (41%) had a good physical recovery. The physical morbidity rate was 22%, and the overall mortality rate was 37%. Twenty-six individuals with a good neurological outcome and five with a fair outcome also underwent reexamination 1 year or more post-SAH, which included a comprehensive evaluation of the quality of life, assessment of cognitive dysfunction, and determination of general adjustment. Five of the patients with a good neurological outcome and all five with a fair outcome (four of whom had had a poor prognosis in the acute stage) showed severe psychosocial and cognitive incapacitation. When functional morbidity, based upon persistent severe cognitive and psychosocial impairment, was included in the outcome assessment, only 33% of the total series was considered to have a favorable outcome. Approximately 60% of the initially good-risk patients (Grades I and II) showed a good physical outcome without concomitant indications of severe cognitive dysfunction and/or psychosocial impairment. Among the good-risk patients with a CT-modified grade, the figure was 70%. It is suggested that in any outcome grading system, persistent cognitive and psychosocial disturbances be taken into account.
Serum and urine zinc response in head-injured patients
Authors: McClain Craig J. , Twyman Diana L. , Ott Linda G. , Rapp Robert P. , Tibbs Phillip A. , Norton Jane A. , Kasarskis Edward J. , Dempsey Robert J. , Young Byron
Published: May 2009

✓ A prospective longitudinal evaluation of serum zinc concentrations was performed in 26 head-trauma patients, and 24-hour urine zinc excretion was determined in 15 of these subjects. Patients had markedly depressed admission serum zinc concentrations (mean ± standard error of the mean: 40.2 ± 3.2 µg/dl; normal values: 70 to 120 µg/dl), which gradually increased during the 16-day study period. All subjects demonstrated increased urinary zinc losses throughout the study period. Urinary zinc excretion was greater in patients with more severe head injuries. Indeed, patients with more severe head trauma had mean peak urinary zinc losses of greater than 7000 µg/day (normal less than 500 (µg/day). The implications of this altered zinc metabolism for protein metabolism, wound healing, and immune function, and the specific role of zinc in brain function and recovery from injury are discussed.
Mixing studies during intracarotid artery infusions in an in vitro model
Authors: Lutz Robert J. , Dedrick Robert L. , Boretos John W. , Oldfield Edward H. , Blacklock J. Bob , Doppman John L.
Published: May 2009

✓ Sporadic instances of retinal damage and of focal brain toxicity have been observed following intracarotid artery infusions of chemotherapeutic agents (such as BCNU and cis-platinum) for the treatment of glioblastomas. The episodic nature of these toxicities is consistent with the possibility that the drug solutions were streaming from the catheter tip and, therefore, were not well mixed or not uniformly distributed in all branches distal to the catheter tip location. To test this hypothesis, an in vitro system was fabricated which included a transparent model of the human carotid artery and its major branches. These were furnished with pulsatile flow of a blood simulant. Dye solutions infused at several infusion rates through various types of catheters in both supraophthalmic and infraophthalmic positions were monitored and recorded on videotape and photographic film. The effluent streams from distal branches of the model were collected, and the relative concentrations of dye in each branch were determined spectrophotometrically. The results indicate that infusate streaming occurs at low infusion rates. In some cases, the concentration in a given branch can be at least five times the expected concentration. Similar occurrences of streaming in vivo could cause focal toxicity. Methods to improve mixing should be used during intra-arterial administration of drugs; these include increasing the infusion rates and improving catheter tip design.
Drug streaming during intra-arterial chemotherapy
Authors: Blacklock J. Bob , Wright Donald C. , Dedrick Robert L. , Blasberg Ronald G. , Lutz Robert J. , Doppman John L. , Oldfield Edward H.
Published: May 2009

✓ Treatment of brain tumors by intra-arterial (IA) chemotherapy is occasionally complicated by sites of focal toxicity in the brain and retina. A possible cause of focal toxicity is non-uniform drug delivery due to intravascular drug streaming. To investigate this phenomenon in vivo, the authors examined the distribution of drug delivery after internal carotid artery (ICA) infusion in rhesus monkeys. Carbon-14 (14C)-labeled iodoantipyrine was delivered into the ICA of eight monkeys at slow infusion rates (1% to 2% of ICA flow) or at fast infusion rates (20% of ICA flow) combined with additional techniques to promote mixing with ICA blood. Two monkeys received intravenous (IV) 14C-antipyrine. Uniformity of delivery was assessed by comparing high-to-low ratios of isotope concentration in four brain regions evaluated by quantitative autoradiography.

There was striking non-uniformity of drug delivery in the slow IA infusion group, with as much as 13-fold differences in drug concentration in anatomically contiguous areas. The values of high-to-low concentration ratios (mean ± standard deviation) in individual autoradiographic planes were: 1) frontoparietal cortex: slow IA infusion 4.54 ± 2.07, fast IA infusion 1.71 ± 0.31, IV infusion 1.30 ± 0.174; 2) frontoparietal white matter: slow IA infusion 2.94 ± 1.45, fast IA infusion 1.59 ± 0.41, IV infusion 1.34 ± 0.21; 3) temporal cortex: slow IA infusion 5.43 ± 3.57, fast IA infusion 1.69 ± 0.24, IV infusion 1.67 ± 0.25; 4) basal ganglia: slow IA infusion 3.6 ± 2.9, fast IA infusion 1.18 ± 0.10, IV infusion 1.09 ± 0.04. Differences between concentration ratios after slow IA and fast IA infusion are significant (p < 0.01); those between fast IA and IV infusion are not significant.

Intra-arterial drug administration at infusion rates analogous to those currently used clinically results in drug streaming with markedly heterogeneous drug deposition in the perfused hemisphere. This may cause suboptimal drug levels in the tumor, and toxic levels at sites within the perfused hemisphere. This effect can be abrogated by techniques that eliminate drug streaming.
Preoperative evaluation and surgical management of the Arnold-Chiari II malformation
Authors: Venes Joan L. , Black Keith L. , Latack Joseph T.
Published: May 2009

✓ The authors report their recent experience with 14 meningomyelocele patients with the Arnold-Chiari II malformation. Three major types of fourth ventricle anomalies seen in the Arnold-Chiari II malformation are defined, based on preoperative magnetic resonance imaging and intraoperative ultrasound studies. The Type A deformity is defined as no cystic dilatation of the fourth ventricle. In the Type B anomaly, there is intracranial dilatation of the fourth ventricle. The Type C deformity involves intraspinal dilatation of the fourth ventricle, either dorsal to the cord or within the substance of the cord. The Type A deformity was most common in infants, and in two cases progression from a Type A to Type B deformity was documented. Recognition of the type of Arnold-Chiari II malformation aids in designing an operative approach more specific to that structural abnormality. Intraoperative ultrasound is a valuable adjunct in localization of the underlying anomalies and permits safe decompression of the fourth ventricle.

The authors' indications for surgery now include failure to thrive due to either early respiratory and swallowing dysfunction, progressive spasticity, or upper-extremity weakness. Nine patients significantly improved following surgery and three patients with a progressively deteriorating course were stabilized by surgery. Decompression of the fourth ventricle by fenestration and internal shunting appears to be well tolerated, even in young infants, and is recommended in the treatment of the Arnold-Chiari II deformity.
Perimesencephalic cistern obliteration: a CT sign of life-threatening shunt failure
Authors: Johnson Dennis L. , Fitz Charles , McCullough David C. , Schwarz Saul
Published: May 2009

✓ Death from cerebrospinal fluid shunt malfunction is a rare but tragic event. The authors describe seven children who when admitted were lethargic but arousable because of shunt failure. Sudden deterioration prompted unscheduled emergency shunt revision in each case. Two children subsequently died. Although neither the history nor the physical findings predicted this life-threatening shunt malfunction, obliteration of the perimesencephalic cistern was apparent on all preoperative computerized tomography (CT) scans. For reference, the scans of 43 other hydrocephalic children were drawn randomly from the hospital files and analyzed. It is concluded that CT evidence of obliteration of the perimesencephalic cistern is a useful warning of life-threatening shunt failure.
Pressure-volume relationships in shunt-dependent childhood hydrocephalus
Authors: Shapiro Kenneth , Fried Arno
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 absorption of CSF (Ro) in 20 shunt-dependent hydrocephalic children acutely ill from shunt malfunction. All children had had ventricles that were near normal or subnormal in size when the shunts were functioning.

The mean intracranial pressure (ICP, ± standard deviation (SD)) at the time of revision was 10.6 ± 6.4 mm Hg. The mean measured PVI (± standard error of the mean) was 18.4 ± 1.1 ml compared to the normal PVI of 17.5 ± 4.4 ml (± SD) predicted for these children. According to paired t-tests, these measured values were similar to those predicted on the basis of neural axis volume for each child, indicating that these children had normal neural axis volume buffering capacity. While the study was in progress, abrupt increases of ICP were documented in all children. These waves were observed spontaneously as well as in response to the addition of volume to the neural axis. In each child a specific threshold pressure along the pressure-volume curve corresponded to the appearance of unstable ICP. The threshold pressures at which this occurred corresponded to a mean neural axis compliance of 0.32 ± 0.07 ml/mm Hg (± SD). The Ro varied as a function of ICP. The Ro measured at ICP's below 15 mm Hg ranged from 2 to 7.5 mm Hg/ml/min and rose to 12 to 30 mm Hg/ml/min at pressures in the 20 to 25 mm Hg range.

The results of this study indicate that neural axis volume buffering capacity is normal in shunt-dependent children who respond to shunting by reconstitution of the cortical mantle. This study indicates that the proximate cause of their abrupt clinical deterioration is unstable ICP, which occurred at a similar point on the pressure-volume curve of all children studied. The correlation of Ro to ICP suggests that CSF absorption does not increase in these children as ICP rises, resulting in movement along relatively normal pressure-volume curves. The functional implications of these parameters are discussed.
Spinal cord tethering after traumatic paraplegia with late neurological deterioration
Authors: Ragnarsson Thorir S. , Durward Quentin J. , Nordgren Richard E.
Published: May 2009

✓ The case of a 49-year-old man with traumatic complete T-5 paraplegia of 30 years' duration is presented. Over the last 10 years, he developed cervical myelopathy suggestive of syringomyelia. Work-up, including metrizamide myelography and delayed computerized tomography scanning, revealed an atrophic cord without a syrinx, and a complete block to contrast material at T-5. At operation, the cord was found to be tethered at the original injury site, and was released by transection. This resulted in immediate improvement in the somatosensory evoked potentials and marked postoperative clinical improvement. It is postulated that cord tethering can cause delayed myelopathy in patients with traumatic cord injury. Release of the tethered cord should be considered if a posttraumatic syrinx is not found.
Fusiform posterior cerebral artery aneurysm treated with excision and end-to-end anastomosis
Authors: Chang Han Soo , Fukushima Takanori , Miyazaki Shinichiro , Tamagawa Teruaki
Published: May 2009

✓ A case of a ruptured fusiform aneurysm of the posterior cerebral artery is reported. The aneurysm was excised and end-to-end anastomosis was carried out between the two ends of the posterior cerebral artery. There is no previous report of a posterior cerebral artery aneurysm treated with this technique. The pertinent literature is reviewed and the significance of this technique in the treatment of unclippable cerebral aneurysms is discussed.
Granulomatous brain tumor caused by Acanthamoeba
Authors: Ofori-Kwakye S. Kwame , Sidebottom David G. , Herbert Joseph , Fischer Edwin G. , Visvesvara Govinda S.
Published: May 2009

✓ A case of a previously healthy 7-year-old girl with a left frontoparietal tumor identified as an Acanthamoeba-induced granuloma is reported, and the literature on Acanthamoeba meningoencephalitis is reviewed. Unlike most reported cases, the Acanthamoeba central nervous system infection presented in this girl as a discrete tumor without meningeal involvement or diffuse encephalitis. A favorable outcome was obtained following total excision of the mass and treatment with ketoconazole.
Heterotopic new bone formation in the cervical spine following head injury
Authors: Groswasser Zeev , Reider-Groswasser Irena
Published: May 2009

✓ Heterotopic new bone formation, associated with head injuries, usually affects the shoulder, elbow, and hip joints. The authors present a case with an unusual involvement of the cervical spine, confirmed by bone scanning and computerized tomography. Although the etiology of heterotopic new bone formation is not well understood, factors such as minor local trauma and increased release of growth hormone are considered as possible contributors. The role of drugs and surgery is discussed.
X-ray-translucent retractors in spine surgery
Authors: Knöringer Peter
Published: May 2009

✓ With surgery of the vertebral column under image intensification, surgical instruments and conventional metal retractors often obscure important x-ray landmarks. Surgery is more difficult, operating time is longer, and exposure to x-rays is increased. The author has developed x-ray-translucent retractors for ventral and dorsal operations. Although for reasons of strength these retractors have somewhat more bulk than equivalent metal retractors, they are sufficiently stable and are compatible with spacial requirements. They can be sterilized and reused.
Recognition of special qualifications in neurological surgery
Authors: Kline David G. , Mahaley Stephen
Published: May 2009

✓ In recent years, one-half of the 23 recognized specialty boards in medicine have begun formally to recognize subspecialization with some type of certification process. One such board, the American Board of Internal Medicine, examines and certifies in 11 subspecialty areas while the American Board of Pathology does so in nine, the American Board of Pediatrics in eight, the American Board of Obstetrics and Gynecology in four, and the American Board of General Surgery in three. Arguments for and against similar recognition of subspecialization within neurosurgery are reviewed. The present position of other specialties and their boards regarding this sensitive issue is summarized, as well as their certification structure. The various pathways available to certifying boards for recognition of subspecialization are also presented.

The American Board of Neurological Surgery (ABNS) has approved a subspecialty certificate called a “certificate of Special Qualification in Critical Care Medicine.” This is a subspecialty that is longitudinally oriented, touching on a number of other specialties in addition to neurosurgery, and thus differs from a vertical subspecialty such as Pediatric Neurosurgery or Cerebrovascular Neurosurgery. The background for development of such a certificate and the current requirements for obtaining it are reviewed. At the present time, the ABNS opposes the possible fragmentation of neurosurgery by offering certification in multiple subspecialty areas. Nonetheless, the current trend in medicine as a whole is in the direction of such subspecialization and its formal recognition. Increasing numbers of neurosurgeons tend to concentrate all or a good deal of their professional efforts in a specific area. Thus, organized neurosurgery must continue to consider methods for subspecialty recognition.
Unusual clinical manifestations of dural arteriovenous malformations
Authors: Viñuela Fernando , Fox Allan J. , Pelz David M. , Drake Charles G.
Published: May 2009

✓ Fourteen patients had classical angiographic findings of intracranial dural arteriovenous malformations (AVM's). They presented with unusual central neurological signs and symptoms, including visual disturbances, hemiparesis, speech disturbances, gait ataxia, diffuse increased intracranial pressure, and intracranial hemorrhage. In 12 of the 14 patients there was a direct correlation between the clinical presentation and the venous drainage characteristics of the AVM's. The symptoms were probably related to a regional steal phenomenon in two patients. Six patients had direct surgical excision of the dural AVM. Five patients underwent endovascular embolization of the malformation and, in one case, the AVM was removed surgically after embolization. In one patient, the external carotid artery in the neck was ligated. Ten of the 14 patients had substantial clinical improvement or cure. A complete anatomical obliteration of the malformation was obtained in seven cases. None of the patients deteriorated clinically after therapy.
Lateral suboccipital approach for vertebral and vertebrobasilar artery lesions
Authors: Heros Roberto C.
Published: May 2009

✓ A modification of the unilateral suboccipital approach is elaborated and illustrated. This modification is useful for aneurysms of the vertebral artery, the vertebrobasilar junction, and the proximal basilar trunk, and for arteriovenous malformations of the inferolateral cerebellum. It entails extreme lateral removal of the rim of the foramen magnum toward the condylar fossa and posterolateral removal of the arch of the atlas toward the exposed vertebral artery. This extra bone removal allows an approach to the front of the brain stem from inferolaterally, after gentle upward and medial retraction of the tonsil, with minimal or no retraction of the medulla.
Management of symptomatic deep venous thrombosis and pulmonary embolism on a neurosurgical service
Authors: Swann Karl W. , Black Peter McL. , Baker Mary F.
Published: May 2009

✓ The authors present a retrospective analysis of the management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in neurosurgical patients at the Massachusetts General Hospital from January, 1978, through June, 1982. There were 44 cases of DVT and 13 cases of PE. Management modalities included observation only, femoral vein ligation, inferior vena cava clipping, transvenous placement of an inferior vena cava filter or umbrella, and anticoagulation therapy. Six (75%) of eight patients with symptomatic DVT who were managed by observation alone had subsequent pulmonary emboli, and three (38%) died. Femoral vein ligation was followed by PE in one of four cases and led to significant leg swelling in two others. Neither observation alone nor femoral vein ligation can be recommended as routine management options. Partial inferior vena cava interruption with a De Weese clip, Kim-Ray Greenfield filter, or Mobin-Uddin umbrella all successfully prevented pulmonary emboli. The major problem associated with these methods was leg edema, which occurred in 47% of patients with clip placement, 25% with filter placement, and 21% with a Mobin-Uddin umbrella. Anticoagulation therapy was associated with a complication rate of 29% and a mortality rate of 15%. Fatal PE and paradoxical hypercoagulability with gangrene of a lower extremity were the causes of death. In one patient, hemorrhage into a glioblastoma occurred following discontinuation of anticoagulation therapy when the coagulation parameters were normal.

The authors conclude that: 1) management with observation alone of patients with symptomatic DVT places the patient at risk for the development of life-threatening pulmonary emboli; 2) the safety and timing of therapeutic anticoagulation in postoperative neurosurgical patients or patients with tumors is unclear; and 3) partial interruption of the inferior vena cava with a transvenous filter successfully prevents PE and may represent a safer alternative to anticoagulation therapy.
Recording of spinal somatosensory evoked potentials for intraoperative spinal cord monitoring
Authors: Whittle Ian R. , Johnston Ian H. , Besser Michael
Published: May 2009

✓ The authors' experience with intradural and epidural recording of spinal somatosensory evoked potentials (SSEP's) during 26 cases of spinal surgery is described. The techniques of monitoring spinal cord function provided good quality SSEP waveforms in patients both with and without neurological deficits. The SSEP configuration and peak latencies remained stable for up to 5 hours during anesthesia with nitrous oxide, halothane, and fentanyl. Patterns of baseline SSEP's were characteristic of different spinal segments. Distortion and asymmetry of these baseline patterns were seen in several patients with spinal neoplasms. Loss of waveform components during surgery occurred with profound hypotension, overdistraction of the vertebral axis, dorsal midline myelotomy, and removal of intramedullary tumors. Persistent loss of waveform components was associated with an acquired neurological deficit. Fluctuations in the amplitude of the SSEP's were common but were not associated with postoperative neurological deficits. Spinal cord monitoring by means of SSEP recording would appear to be useful during extradural spinal surgery, but there are limitations associated with this technique during some types of intradural surgery.
Effect of nimodipine on intracellular brain pH, cortical blood flow, and EEG in experimental focal cerebral ischemia
Authors: Meyer Fredric B. , Anderson Robert E. , Yaksh Tony L. , Sundt Thoralf M.
Published: May 2009

✓ Intracellular brain pH, cortical blood flow, and electroencephalograms (EEG's) were recorded in severely and moderately ischemic regions in 10 control and 10 nimodipine-treated rabbits prior to and following major branch occlusion of the middle cerebral artery (MCA). Preocclusion cortical blood flow was 51 ml/100 gm/min and intracellular brain pH was 7.01 in both the control and the treated animals. After MCA occlusion, the severely ischemic regions in the control group showed initial and 4-hour postocclusion flows of 12.7 and 5.2 ml/100 gm/min with a brain pH of 6.64 and 6.08, respectively. In animals given nimodipine after MCA occlusion, blood flow increased from 10.5 to 18.8 ml/100 gm/min, with an associated elevation in intracellular brain pH from 6.57 to 6.91. Comparable findings were observed in areas of moderate ischemia. Improvements in cortical blood flow, intracellular brain pH, and EEG attenuations produced by nimodipine were all statistically significant. Inspection of the cortex revealed reversal of cortical pallor and small-vessel spasm following treatment with nimodipine. It is hypothesized that nimodipine exerts its effects through reversal of ischemia-induced secondary vasoconstriction, and that this drug may be an important adjunctive treatment for patients with focal cerebral ischemia.
Protection against experimental ischemic spinal cord injury
Authors: Robertson Claudia S. , Foltz Richard , Grossman Robert G. , Goodman J. Clay
Published: May 2009

✓ The authors have studied the protection against ischemic damage to rabbit spinal cord by pretreatment with agents that block neuronal activity and directly or indirectly reduce tissue metabolism. Hypothermia, thiopental, magnesium, lidocaine, and naloxone were used to pretreat the spinal cord prior to ischemia. Hypothermia and thiopental provided comparable protection: they each increased the duration of ischemia required to produce neurological deficits in 50% of the animals from 26 to 41 minutes. They also increased from 10 to 30 minutes the time that the postsynaptic waves of the spinal somatosensory evoked potential (SSEP) could be absent and the animal still have neurological recovery. Hypothermia and thiopental, when used together, increased the duration of ischemia required to produce neurological deficits to 57 minutes in 50% of the animals. Naloxone increased the duration of ischemia required to produce neurological deficits to 36 minutes in 50% of the animals, and increased to 20 minutes the time that the postsynaptic waves of the SSEP could be absent and the animal still have neurological recovery. Magnesium pretreatment improved neurological outcome, possibly by improving collateral circulation as the SSEP did not fail completely during aortic occlusion in all animals. Lidocaine was not beneficial, perhaps because of the prolonged hypotension that resulted.
Focal brain edema associated with acute arterial hypertension
Authors: Hatashita Shizuo , Hoff Julian T. , Ishii Shozo
Published: May 2009

✓ Acute arterial hypertension was studied in normal cats to determine its role in the formation of brain edema. Arterial hypertension was induced for 30 minutes by inflation of a balloon catheter situated in the descending aorta. Cerebral edema was evaluated by gross and microscopic observations, tissue water content by wet/dry weights, and blood-brain barrier (BBB) permeability by extravasation of horseradish peroxidase (HRP) and Evans blue dye. For 1 hour after the hypertensive insult, tissue pressure and regional cerebral blood flow (rCBF) were measured from the arterial boundary zone and from a non-boundary region, and intracranial pressure was recorded from the lateral ventricle as ventricular fluid pressure.

Focal lesions with increased BBB permeability to Evans blue dye or HRP were usually located symmetrically in the cortex, corresponding to the occipitoparietal parts of the arterial boundary zones. The increase in water content was found only in areas of increased permeability. Tissue pressure increased simultaneously with the abrupt rise in blood pressure, and an increase in rCBF paralleled the elevation of blood pressure. Tissue pressure and rCBF returned to a steady state when blood pressure returned to normal. There were no differences in tissue pressure or rCBF between the arterial boundary zone and the non-boundary zone, even during arterial hypertension. In cerebral hemispheres examined 48 hours after the hypertensive challenge, brain edema had not continued to develop.

The data indicate that acute arterial hypertension may produce focal brain edema with increased permeability of the BBB in the cortex of normal brain, particularly in the arterial boundary zones. The authors postulate that increased cerebral blood volume, high intraluminal pressure, and breakthrough of autoregulation play an important role in the formation of hypertensive brain edema.
Cerebral astroblastoma: immunohistochemical and ultrastructural features
Authors: Husain Aliya N. , Leestma Jan E.
Published: May 2009

✓ Astroblastoma is a rare glial tumor occurring predominantly in the cerebral hemispheres of young adults. Foci of astroblastoma-like patterns are commonly found in glioblastomas and other malignant glial tumors and cause confusion over the classification of the tumor as an individual entity. However, the existence of astroblastoma in histologically pure form and its typically long history, as compared with the more aggressive gliomas in which it may occur as a pattern, distinguish it as a separate and distinct tumor. A case of pure astroblastoma of the cerebral hemisphere is reported in a 3-year-old child with a 5-year course. The tumor has been resected five times, and its pattern has remained the same in all recurrences. The child is presently alive with some neurological deficit. The immunohistochemical and electron microscopical findings of this tumor are presented, and the historical development of the entity is discussed.
Clip-grafts in microvascular decompression of the posterior fossa
Authors: Laws Edward R. , Kelly Patrick J. , Sundt Thoralf M.
Published: May 2009

✓ A method is described for the protection of the trigeminal root from recurrent vascular irritation or compression after posterior fossa microvascular decompression. A vascular clip-graft, using a Sundt clip of suitable size, is applied to the sensory root of the trigeminal nerve. The technique has proven safe and effective in a series of nine patients followed for up to 28 months.
W. W. Keen and the dawn of American neurosurgery
Authors: Bingham William F.
Published: May 2009

✓ Before the turn of the century, W. W. Keen was the most celebrated neurosurgeon in the United States. During the Civil War he served as a surgeon in the Union Army. He collaborated with Mitchell and Morehouse in clinical studies that culminated in their publishing Gunshot Wounds and Other Injuries of Nerves. In 1887, he was the first surgeon in the Americas to remove a benign brain tumor. He perfected a technique for ventricular puncture, devised operations for spasmodic torticollis, microcephalus, and tic douloureaux, and introduced many European neurosurgical techniques to the United States. An astute clinician and excellent teacher, Keen had no research interests other than anatomical and pathological dissections. He published over 50 papers on neurosurgical topics, in addition to articles on numerous other subjects. Although recognized as a pioneer in neurosurgery, he is not usually considered a founder of neurosurgery in the United States because of his failure to develop the specialty further than his contemporaries in the remainder of the neurosurgical world. This failure related not to his abilities, but probably to the fact that he was elderly before it became technically possible to perform safe and effective intracranial procedures.
Neurological manifestations of intracranial dural arteriovenous malformations
Authors: Lasjaunias Pierre , Chiu Ming , Ter Brugge Karel , Tolia Atul , Hurth Michel , Bernstein Mark
Published: May 2009

✓ The authors describe their experience with four cases of dural arteriovenous malformation (AVM) which led them to analyze the clinical aspects of these lesions in an attempt to understand their pathophysiology. An additional 191 previously reported cases of dural AVM's were reviewed with special attention to the mechanism of intradural, central, and peripheral nervous system manifestations. Apart from the peripheral cranial nerve symptoms, which are most likely due to arterial steal, the central nervous system (CNS) symptoms appear to be related to passive venous hypertension and/or congestion. Generalized CNS symptoms can be related to cerebrospinal fluid malabsorption due either to increased pressure in the superior sagittal sinus, to venous sinus thrombosis, or to meningeal reaction resulting from minimal subarachnoid hemorrhages. These phenomena are not related to the anatomical type of venous drainage. On the other hand, focal CNS symptoms are specifically indicative of cortical venous drainage. Seizures, transient ischemic attacks, motor weakness, and brain-stem and cerebellar symptoms can be encountered depending on the territory of the draining vein or veins. Therefore, the localizing value of focal CNS symptomatology relates to the venous territory and not to the nidus or to the arterial supply characteristics of dural AVM's. Furthermore, the venous patterns of various dural AVM's at the base of the skull are expressed by differences in their clinical presentation. Dural AVM's of the floor of the anterior cranial fossa and of the tentorium are almost always drained by the cortical veins and, therefore, have a high risk of intradural bleeding.

The remarkable similarities in the manifestations of dural and brain AVM's and the differences in the manifestations of dural and spinal dural AVM's are pointed out. High-quality angiograms and a multidisciplinary approach to the study of dural AVM's will provide the best understanding of their symptoms and, therefore, the most appropriate treatment strategy.
Differential diagnosis of CT-hypodense cranial lesions with indium-111-oxine-labeled leukocytes
Authors: Bellotti Carlo , Aragno Maria G. , Medina Massimo , Viglietti Anna L. , Oliveri Giuseppe , Ettorre Francesco , Barrale Salvatore , Camuzzini Gianfranco
Published: May 2009

✓ Scintigraphy using indium-111-oxine-labeled white blood cells was used as a complementary diagnostic study in the differential diagnosis of 20 intracerebral cystic lesions for which computerized tomography scanning did not exclude cerebral abscess. To lower the rate of false-positive findings with scintiscanning, three criteria of positivity were tested in the 20 lesions. The most stringent criterion yielded 100% sensitivity, 94% specificity, and 96% diagnostic accuracy. The clinical and surgical implications of these results are discussed.
In vitro photoradiation therapy of the rat 9L gliosarcoma
Authors: Hamilton Douglas , McKean John D. S. , Tulip John , Boisvert Donald , Cummins Judy
Published: May 2009

✓ The authors have investigated various factors involved in the photoradiation treatment of 9L glioma cells. The cells were grown in tissue culture and exposed to light from a laser source that allowed accurate quantitation of the light energy. Cell death was determined following treatment using the trypan blue exclusion test. It was shown that the treatment is very wavelength-dependent following the absorption spectrum of hematoporphyrin derivative (HPD). The absorption peaks in the lower part of the spectrum are more efficient than those of higher wavelengths. Photoradiation therapy is more effective the higher the concentration of HPD. Intensity of light is a very important factor in calculating the total dose of light necessary for this treatment.
Superoxide production in experimental brain injury
Authors: Kontos Hermes A. , Wei Enoch P.
Published: May 2009

✓ The appearance of superoxide anion radicals in cerebral extracellular space during and after experimental fluid-percussion brain injury was investigated in anesthetized cats equipped with cranial windows. Superoxide was detected by demonstrating the presence of superoxide dismutase (SOD)-inhibitable reduction of nitroblue tetrazolium (NBT). The SOD-inhibitable rate of reduction of NBT was 3.52 ± 0.72 nM/min/sq cm during brain injury and 4.11 ± 0.74 nM/min/sq cm 1 hour after injury. No significant superoxide production was detected in control animals. The sustained arteriolar dilation and reduced responsiveness to the vasoconstrictor effects of arterial hypocapnia observed 30 minutes after brain injury were eliminated by after-treatment with topical SOD (60 U/ml) and catalase (40 U/ml). The results show that experimental brain injury causes the generation and appearance in extracellular fluid space of superoxide. Superoxide production continues for at least 1 hour following injury. The sustained dilation and abnormal responsiveness of cerebral arterioles after injury are due to the continued generation of superoxide and other radicals derived from it. These functional changes can be reversed by after-treatment with appropriate scavenging agents.
Papillary meningioma involving the oculomotor nerve in an infant
Authors: Piatt Joseph H. , Campbell Gerald A. , Oakes W. Jerry
Published: May 2009

✓ A 6-month-old child with an isolated oculomotor nerve palsy was found to have a papillary meningioma infiltrating the nerve along its intracranial course adjacent to the midbrain. The clinical implications of this unusual histological variant are discussed.
Intraoperative angiography using a portable digital subtraction unit
Authors: Foley Kevin T. , Cahan Leslie D. , Hieshima Grant B.
Published: May 2009

✓ A portable digital subtraction unit has been used in the operating room as an important improvement in obtaining high-quality intraoperative angiograms. This digital subtraction system offers several advantages over previously described techniques for intraoperative studies. Not only are the images of good quality, but also the dose of contrast medium is reduced and a real-time imaging capability allows the surgeon to visualize the passage of contrast agent dynamically. Arterial injections may be performed by selective femoral cerebral catheterization, puncture of the cervical carotid artery, retrograde catheterization via the superficial temporal artery, or puncture of an intracranial vessel at the time of surgery.
Intracranial tumors in patients with facial pain
Authors: Bullitt Elizabeth , Tew John M. , Boyd Jane
Published: May 2009

✓ Over the past 10 years, 2000 patients with facial pain have been evaluated at the Mayfield Neurologic Institute. Sixteen of these patients were found to harbor intracranial tumors. The presenting features of this group of patients are analyzed, and the literature reviewed. Peripherally placed tumors tend to cause atypical facial pain associated with sensory loss. Middle fossa tumors may present as trigeminal neuralgia, but usually cause severe pain of an atypical nature and a progressive neurological deficit. Posterior fossa tumors are most likely to cause trigeminal neuralgia; these neoplasms are usually accompanied by subtle neurological deficits and are readily detected by current diagnostic studies.