bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endovascular treatment of acutely ruptured and unruptured aneurysms of the basilar bifurcation
Authors: Raymond Jean , Roy Daniel , Bojanowski Michel , Moumdjian Robert , L'Espérance Georges 
Published: June 2009

✓ The surgical treatment of basilar bifurcation aneurysms is difficult and the need for an alternative approach is frequently stated. To assess the efficacy and safety of endovascular treatment of aneurysms located at the basilar bifurcation, the authors prospectively studied angiographic results, clinical results, and complications in 31 patients treated with Guglielmi detachable coils (GDCs). Patients treated acutely after subarachnoid hemorrhage (SAH) were graded according to the Hunt and Hess classification and clinical outcome was determined at 1- and 6-month intervals according to the Glasgow Outcome Scale (GOS).
There were 18 women and 13 men, ranging in age from 34 to 67 years (mean age 48 years). Twenty-three were treated acutely after SAH. Clinical Hunt and Hess grades at presentation were as follows: Grade I, six patients; Grade II, three; Grade III, 11; Grade IV, two; and Grade V, one. The GOS score for the group of patients treated acutely was: GOS I, 18 patients; GOS II, III, and IV, one patient each; and GOS V, two patients. There were seven technical complications in this group, most often asymptomatic, but one patient died after aneurysm rupture during treatment and one had residual diplopia at 4 months. Eight patients were treated for incidental basilar bifurcation aneurysms. One technical complication with no neurological deficit occurred in this group of patients with incidental aneurysms.
Immediate angiographic results were considered to be satisfactory in 94% of patients, with complete obliteration in 42% and residual neck and dog ears in 52%. There was no bleeding episode after treatment during clinical follow-up periods ranging from 3 to 42 months (mean 15.5 months in 29 surviving patients). Angiographic results were available for 27 patients at 6 months and were as follows: 30% of the lesions were completely obliterated, 59% presented some residual neck, and 11% showed some opacification of the aneurysm sac. During the follow-up period of up to 42 months, a total of seven recurrences were noted, necessitating retreatment with GDCs in five patients.
Endovascular treatment of basilar bifurcation aneurysms prevented rebleeding and could be performed without clinically significant complications in 94% of patients. Clinical results after SAH compared favorably with surgical series. Morphological results appear less satisfactory, and long-term angiographic follow-up review is mandatory to detect recurrences.
Waveform changes due to conduction block and their underlying mechanism in spinal somatosensory evoked potential: a computer simulation
Authors: Tani Toshikazu , Ushida Takahiro , Yamamoto Hiroshi , Okuhara Yoshiyasu 
Published: June 2009

✓ Based on a square-wave solid-angle analysis, a simplified mathematical model was produced for computing a sequence of potential change in a volume conductor generated by an impulse traveling along a nerve fiber. A conduction block was simulated as a phenomenon in which a depolarization wavefront stops traveling when it reaches a certain point, although the following repolarization wavefront continues to travel until it reaches the same point. The spinal somatosensory evoked potential (SSEP) was produced as an algebraic sum of simulated nerve fiber action potentials (NFAPs).With a conduction block, an NFAP that was normally triphasic showed a positive—negative diphasic wave with reduced negativity at the point of the block, diphasic waves with enhanced negativity at points immediately preceding the block, and initial-positive waves alone or abolition of any wave at points beyond the block. The absence of their terminal-positive phases paradoxically enhanced the negative peak of the spinal SSEPs in a partial block that involved only the constituent fastest fibers, because phase cancellation of the phases between the terminal-positive phases of the fastest fibers and the negative phases of the slower fibers, which normally happens, failed to occur. At the points immediately preceding the block, the identical mechanism sustained the spinal SSEP enhancement even when every fiber was included in the block. The computer model predicted that localization of the precise site of conduction block can be achieved by demonstrating an abrupt reduction in the amplitude of the spinal SSEP, which is accompanied by an increased negative wave caudally and an enhanced monophasic positive wave rostrally.
Normal perfusion pressure breakthrough: the role of capillaries
Authors: Sekhon Lali H. S. , Morgan Michael K. , Spence Ian 
Published: June 2009

✓ Excision of human cerebral arteriovenous malformations (AVMs) can be complicated by postoperative edema and hemorrhage in adjacent brain tissue, despite the complete excision of the malformation. Various theories have purported to explain the hemodynamic basis for this predisposition, including disordered autoregulation causing “normal perfusion pressure breakthrough” and obstruction of venous drainage leading to “occlusive hyperemia.” This study did not evaluate the arterial or venous circulations in this scenario, but rather examined the capillaries in adjacent brain parenchyma for any structural deficiencies that would predispose the brain to the postoperative formation of edema and hemorrhage.
Arteriovenous fistulas (AVFs) were created surgically in the necks of 10 male Sprague—Dawley rats, which caused chronic cerebral hypoperfusion with a reduction in cerebral blood flow of between 25% and 50%. Ten age-matched animals were used as controls. Twenty-six weeks after AVF formation the animals were killed and perfusion fixed. Their brain tissue was prepared for light microscopic studies by staining for glial fibrillary acidic protein or for transmission electron microscopy. In the CA1 pyramidal cell region of the hippocampus, it was found that in the animals with AVFs there was increased capillary density and absent astrocytic foot processes in some of these vessels. It was concluded that these vessels had developed as a result of neovascularization in response to chronic cerebral ischemia and that their anatomical configuration made them prone to mechanical weakness and instability following the increase in perfusion pressure that occurs in adjacent brain parenchyma after AVM excision.
The authors believe that this study pinpoints a structural accompaniment to the hemodynamic changes that occur in brain tissue in the vicinity of cerebral AVMs that predispose these areas to the formation of edema and hemorrhage after AVM excision.
Isolation and characterization of human malignant glioma cells from histologically normal brain
Authors: Silbergeld Daniel L. , Chicoine Michael R. 
Published: June 2009

✓ Brain invasion prevents complete surgical extirpation of malignant gliomas; however, invasive cells from distant, histologically normal brain previously have not been isolated, cultured, and characterized. To evaluate invasive human malignant glioma cells, the authors established cultures from gross tumor and histologically normal brain. Three men and one woman, with a mean age of 67 years, underwent two frontal and two temporal lobectomies for tumors, which yielded specimens of both gross tumor and histologically normal brain. Each specimen was acquired a minimum of 4 cm from the gross tumor. The specimens were split: a portion was sent for neuropathological evaluation (three glioblastomas multiforme and one oligodendroglioma) and a portion was used to establish cell lines. Morphologically, the specimens of gross tumor and histologically normal brain were identical in three of the four cell culture pairs. Histochemical staining characteristics were consistent both within each pair and when compared with the specimens sent for neuropathological evaluation. Cultures demonstrated anchorage-independent growth in soft agarose and neoplastic karyotypes. Growth rates in culture were greater for histologically normal brain than for gross tumor in three of the four culture pairs. Although the observed increases in growth rates of histologically normal brain cultures do not correlate with in vivo behavior, these findings corroborate the previously reported stem cell potential of invasive glioma cells. Using the radial dish assay, no significant differences in motility between cultures of gross tumor and histologically normal brain were found.
In summary, tumor cells were cultured from histologically normal brain acquired from a distance greater than 4 cm from the gross tumor, indicating the relative insensitivity of standard histopathological identification of invasive glioma cells (and hence the inadequacy of frozen-section evaluation of resection margins). Cell lines derived from gross tumor and histologically normal brain were usually histologically identical and demonstrated equivalent motility, but had different growth rates.
Tremor control after pallidotomy in patients with Parkinson's disease: correlation with microrecording findings
Authors: Taha Jamal M. , Favre Jacques , Baumann Thomas K. , Burchiel Kim J. 
Published: June 2009

✓ The goals of this study were to analyze the effect of pallidotomy on parkinsonian tremor and to ascertain whether an association exists between microrecording findings and tremor outcome.
Forty-four patients with Parkinson's disease who had drug-induced dyskinesia, bradykinesia, rigidity, and tremor underwent posteroventral pallidotomy. Using a 1-µ-tip tungsten electrode, microrecordings were obtained through one to three tracts, starting 10 mm above the pallidal base. Tremor severity was measured on a patient-rated, 100-mm Visual Analog Scale (VAS), both preoperatively and 3 to 9 months (mean 6 months) postoperatively.
Preoperatively, tremor was rated as 50 mm or greater in 24 patients (55%) and as less than 25 mm in 13 patients (30%). Postoperatively, tremor was rated as 50 mm or greater in five patients (11%) and less than 25 mm in 29 patients (66%). The difference was significant (p = 0.0001). Four patients (9%) had no postoperative tremor. Tremor improved by at least 50% in eight (80%) of 10 patients in whom tremor-synchronous cells were recorded (Group A) and in 12 (35%) of 34 patients in whom tremor-synchronous cells were not recorded (Group B). This difference was significant (p = 0.03). Tremor improved by at least 50 mm in all (100%) of the seven Group A patients with severe (≥ 50 mm) preoperative tremor and in nine (53%) of 17 Group B patients with severe preoperative tremor. This difference was also significant (p = 0.05).
The authors proffer two conclusions: 1) after pallidotomy, tremor improves by at least 50% in two-thirds of patients with Parkinson's disease who have severe (≥ 50 mm on the VAS) preoperative tremor; and 2) better tremor control is obtained when tremor-synchronous cells are included in the lesion.
Repositioning of the vertebral artery as treatment for neurovascular compression syndromes
Authors: Bejjani Ghassan K. , Sekhar Laligam N. 
Published: June 2009

✓ Neurovascular compression syndromes are usually treated by interposing Teflon felt or padding or some other implant between the offending vessel and the nerves. However, this cannot be done in some cases in which ectatic vertebrobasilar arteries are involved. In these instances, alternative techniques must be used.
The authors report the use of a sling made of Prolene to reposition the vertebral artery in two patients with neurovascular compression disorder. The clinical results were gratifying, with complete resolution of the patients' symptoms.
Compression by large vessels is an uncommon but important source of neurovascular compression in patients with trigeminal neuralgia, hemifacial spasm, disabling positional vertigo, and, possibly, hypertension. The technique described may be useful to surgeons treating these problems.
Paradoxical effects of acute ethanolism in experimental brain injury
Authors: Kelly Daniel F. , Lee Stefan M. , Pinanong Patty A. , Hovda David A. 
Published: June 2009

✓ Acute ethanol intoxication is a frequent complicating factor in human head injury, yet its impact on neurological outcome remains poorly defined. This study was undertaken to assess the effect of varying levels of preinjury ethanol on early postinjury mortality, recovery of motor function, and degree of neural degeneration after cortical contusion injury in the rat. Adult rats were pretrained on a beam-walking task, then randomized to one of five groups: low-dose ethanol and injury (1 g/kg, 16 animals); moderate-dose ethanol and injury (2.5 g/kg, 11 animals); high-dose ethanol and injury (3 g/kg, 17 animals); no ethanol and injury (nine animals); or ethanol and sham injury (seven animals). Forty minutes after intraperitoneal injection of ethanol or saline, the rats received a pneumatic piston—induced contusion injury of the left primary motor cortex. Their beam-walking ability was assessed daily for the next 7 days. At 4 weeks postinjury, the brains were sectioned and the dimensions of the cortical lesions were determined.
Preinjury ethanol administration was associated with an acute postinjury mortality rate of 29.5% (p < 0.05); the highest mortality rate (47.1%) occurred in the high-dose ethanol group, whereas no deaths occurred in the animals in the no ethanol or sham-injured groups (p < 0.01). However, injured animals receiving low- and moderate-dose ethanol had significantly less severe beam-walking impairment initially, and a more rapid return to normal beam-walking ability, compared to the no and high-dose ethanol groups (p < 0.05). Additionally, the mean lesion volumes were significantly smaller in the low- and moderate-dose ethanol treatment groups compared to the no and high-dose ethanol groups (23.2 ± 8 mm3 and 29 ± 6.7 mm3 vs. 52 ± 8.8 mm3 and 53.7 ± 10.9 mm3, respectively, p < 0.01). In this cortical contusion model, the presence of ethanol before injury appears to exert a potent neuroprotective effect when administered in low or moderate doses. This action is postulated to result from ethanol-induced inhibition of N-methyl-d-aspartate receptor-mediated excitotoxicity. The loss of neuroprotection and increased mortality rates observed with high-dose ethanol may be related to ethanol-induced hemodynamic and respiratory depression.
Stereotactic biopsy of nonpolar tumors in the dominant hemisphere: a prospective study of effects on language functions
Authors: Thomson Ann-Marie , Taylor Robert , Fraser Diane , Whittle Ian R. 
Published: June 2009

✓ A prospective study of patients undergoing computerized tomography (CT)—guided stereotactic biopsy of nonpolar tumors in the dominant hemisphere was undertaken to determine if stereotactic biopsy caused a deterioration of language functions. Language was assessed using the Western Aphasia Battery (WAB) and the Boston Naming Test (BNT) before and after a biopsy sample was obtained. Of 16 patients studied, five (31%) were dysphasic preoperatively. After the biopsy the Aphasia Quotient (AQ), derived from the WAB, had significantly deteriorated in four (80%) of these patients, whereas in the fifth it remained relatively unchanged. One of these patients with an extensive infiltrating hemispheric oligoastrocytoma subsequently recovered normal language function after radiotherapy. In 10 of the 11 patients who had normal language function preoperatively there were no deleterious changes after biopsy in either the WAB subtest or BNT scores. In the other patient whose WAB score was normal preoperatively, there was a significant deterioration in postoperative AQ. This patient, who declined steroid therapy before and after biopsy, had a glioblastoma multiforme in Wernicke's area. A postoperative CT scan revealed no changes from what was shown on preoperative scan.
This clinical study shows that CT-guided stereotactic biopsy of nonpolar tumors in the dominant hemisphere using the Brown-Roberts-Wells system and the Sedan—Nashold biopsy cannula carries a 9% risk (95% confidence intervals 0–26%) of impairing language functions if the patient is not dysphasic preoperatively. If the patient is dysphasic preoperatively, there is a very high risk of aggravating the dysphasia with stereotactic biopsy.
Basilar invagination in osteogenesis imperfecta and related osteochondrodysplasias: medical and surgical management
Authors: Sawin Paul D. , Menezes Arnold H. 
Published: June 2009

✓ Osteogenesis imperfecta (OI) is a heritable disorder of bone development caused by defective collagen synthesis. Basilar invagination is an uncommon but devastating complication of this disease. The authors present a comprehensive strategy for management of craniovertebral anomalies associated with OI and related osteochondrodysplasias.Twenty-five patients with congenital osteochondrodysplasias (18 OI, four Hajdu—Cheney syndrome, and three spondyloepiphyseal dysplasia) and basilar invagination were evaluated between 1985 and 1995. The male/female ratio in this cohort was 1:1. The mean age at presentation was 11.9 years (range 13 months–20 years). Fourteen patients (56%) presented during adolescence (11–15 years of age). Symptoms and signs included headache (76%), lower cranial nerve dysfunction (68%), hyperreflexia (56%), quadriparesis (48%), ataxia (32%), nystagmus (28%), and scoliosis (20%). Four patients (16%) were asymptomatic. Seven (28%) had undergone previous posterior fossa decompression; one had also undergone ventral decompression. Imaging findings included basilar invagination (100%), ventral brainstem compression (84%), hydrocephalus (32%), hindbrain herniation (28%), and syringomyelia/syringobulbia (16%).Patients with hydrocephalus underwent ventricular shunt placement. Reducible basilar invagination (40%) was treated with posterior fossa decompression and occipitocervical fusion. Those with irreducible ventral compression (60%) underwent transoral—transpalatopharyngeal decompression followed by occipitocervical fusion. All patients improved initially. However, basilar invagination progressed radiographically in 80% (symptomatic in 24%) despite successful fusion. Prolonged external orthotic immobilization with the modified Minerva brace afforded symptomatic improvement and arrested progression of the deformity. The mean follow-up period was 5.9 years (range 1.1–10.5 years).Ventral brainstem compression in OI should be treated with ventral decompression, followed by occipitocervical fusion with contoured loop instrumentation to prevent further squamooccipital infolding. Despite fusion, however, basilar invagination tends to progress. Prolonged immobilization (particularly during adolescence) may stabilize symptoms and halt further invagination. This study represents the largest series to date addressing craniovertebral anomalies in OI and related congenital bone softening disorders.
Revision of anterior cervical pseudarthrosis with anterior allograft fusion and plating
Authors: Coric Domagoj , Branch Charles L. , Jenkins Jeffrey D. 
Published: June 2009

U Anterior cervical discectomy and fusion is an efficacious procedure used to treat a variety of cervical spinal disorders, including spondylosis, myelopathy, herniated discs, trauma, and degenerative disc disease. Pseudarthrosis, or failure of fusion, may be the most common complication of spinal fusion procedures. Nineteen consecutive patients with symptomatic pseudarthrosis following failed anterior cervical fusions were treated with anterior cervical revision using iliac crest allografts and either the Cervical Spine Locking Plate system (10 patients) or the Trapezial Osteosynthetic Plate system (nine patients). The mean age of the nine men and 10 women undergoing treatment was 49.1 years (range 25–72 years). Eleven patients (57.9%) exhibited pseudarthrosis at one level, six (31.5%) at two levels, and two (10.5%) at three levels. The indications for revision were intractable neck pain with radiculopathy (17 patients) or myelopathy (two patients), with evidence of pseudarthrosis on plain cervical radiography as well as computerized tomography (CT) or single-photon emission computerized tomography (SPECT) scanning, or both. All eight patients evaluated with SPECT showed increased focal uptake consistent with pseudarthrosis, which was subsequently confirmed intraoperatively in all eight. The average follow-up period was 22.4 months (range 12–42 months).Solid osseous fusion was achieved over all 28 levels in all 18 patients available for follow-up review (100%). One patient died 4 months postoperatively from myocardial infarction related to preexisting coronary artery disease. There were no intraoperative complications; postoperatively, two patients (10.5%) experienced transient hoarseness.Anterior revision of failed cervical fusions using allograft interbody fusion material and anterior plating is a safe and efficacious procedure. In this series, the use of allografts avoided donor site morbidity without adversely affecting fusion rates. Rigid internal fixation was achieved by means of anterior plating without increasing surgical morbidity rates. The SPECT imaging technique has the potential to reliably confirm the diagnosis of pseudarthrosis.
Reduction of spinal cord injury by administration of iloprost, a stable prostacyclin analog
Authors: Taoka Yuji , Okajima Kenji , Uchiba Mitsuhiro , Murakami Kazunori , Harada Naoaki , Johno Masayoshi , Naruo Masakuni , Okabe Hiroaki , Takatsuki Kiyoshi 
Published: June 2009

✓ To investigate whether iloprost, a stable analog of prostacyclin, is useful for the prevention of posttraumatic spinal cord injury, we examined its effects on compression trauma—induced spinal cord injury in rats. Spinal cord injury was induced by applying a 20-g weight for 20 minutes to the spinal cord at the level of T-12, resulting in motor disturbances in the hindlimbs. These motor disturbances, evaluated using Tarlov's index, were markedly attenuated in rats with nitrogen mustard—induced leukocytopenia. Administration of iloprost also attenuated the motor deficits. Histological examination revealed that intramedullary hemorrhages observed 24 hours after trauma were significantly attenuated in leukocytopenic animals and in animals that received iloprost. The accumulation of leukocytes at the site of trauma, evaluated by measuring tissue myeloperoxidase activity, significantly increased with time following the trauma, peaking at 3 hours postinjury. Spinal cord myeloperoxidase activity in sham-operated animals did not increase postoperatively. Leukocyte depletion and administration of iloprost reduced the accumulation of leukocytes in the damaged spinal cord segment 3 hours posttrauma.These findings indicate that iloprost attenuates motor disturbances induced by spinal cord trauma and that its therapeutic efficacy can be partly explained by its inhibition of leukocyte accumulation at the traumatized site.