bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clinical and electrophysiological expression of deafferentation pain alleviated by dorsal root entry zone lesions in rats
Authors: Guenot Marc , Bullier Jean , Sindou Marc 
Published: May 2009

Object. The aims of this study were to construct an animal model of deafferentation of the spinal cord by brachial plexus avulsion and to analyze the effects of subsequent dorsal root entry zone (DREZ) lesions in this model. To this end, the authors measured the clinical and electrophysiological effects of total deafferentation of the cervical dorsal horn in rats and evaluated the clinical efficacy of cervical DREZ lesioning.
Methods. Forty-three Sprague—Dawley rats were subjected to total deafferentation of the right cervical dorsal horn by performing a posterior rhizotomy from C-5 to T-1. The clinical effects of this deafferentation, namely self-directed mutilations consisting of scraping and/or ulceration of the forelimb skin or even autotomy of some forelimb digits, were then evaluated. As soon as some of these clinical signs of pain appeared, the authors performed a microsurgical DREZ rhizotomy ([MDR], microincision along the deafferented DREZ and dorsal horn). Before and after MDR, single-unit recordings were obtained in the deafferented dorsal horn and in the contralateral (healthy) side. The mean frequency of spontaneous discharge from the deafferented dorsal horn neurons was significantly higher than that from the healthy side (36.4 Hz compared with 17.9 Hz, p = 0.03).
After deafferentation, 81.4% of the rats developed clinical signs corresponding to pain following posterior rhizotomy. Among these animals, scraping was observed in 85.7% of cases, ulceration (associated with edema) in 37.1%, and autotomy in 8.5%. These signs appeared a mean 5.7 weeks (range 1–12 weeks) after deafferentation.
Thirteen rats benefited from an MDR; nine (69%) experienced a complete cure, that is, a total resolution of scraping or ulceration (a mean 4.6 weeks after MDR). In contrast, only one of 11 sham-operated animals showed signs of spontaneous recovery (p = 0.01).
Conclusions. These results emphasize the role of the spinal dorsal horn in the genesis of deafferentation pain and suggest that dorsal horn deafferentation by cervical posterior rhizotomy in the rat provides a reliable model of chronic pain due to brachial plexus avulsion and its suppression by MDR.
A reproducible model of an epidural mass lesion in rodents. Part II: Characterization by in vivo magnetic resonance imaging
Authors: Bendszus Martin , Burger Ralf , Vince Giles Hamilton , Solymosi Laszlo 
Published: May 2009

Object. The goal of this study was to characterize a novel epidural space-occupying lesion caused by balloon expansion in rodents by using sequential in vivo magnetic resonance (MR) imaging
Methods. Ten Sprague—Dawley rats were intraperitoneally sedated. A trephination was performed over the left parietal cortex to attach a balloon-expansion device, which was secured with dental cement. Measurements were performed using a 1.5-tesla MR imaging device to obtain sequential T2-weighted and diffusion-weighted (DW) sequences in the coronal plane. A three-dimensional, constructed interference in steady state sequence was used for calculation of the balloon volume. The animal's temperature, heartbeat, and the arterial percentage of oxygen saturation were monitored continuously. After a baseline examination had been performed, the balloon was inflated for a 30-minute period until it reached a maximum volume of 0.3 ml; this procedure was followed by a period of sustained inflation lasting 30 minutes, balloon deflation, and a period of reperfusion lasting 3 hours. After perfusion fixation of the animals, morphometric analysis of the lesion size and examination of the percentage of viable neurons in the hippocampus were performed.
Magnetic resonance imaging allowed for the precise visualization of the extension and location of the epidural mass lesion, narrowing of the basal cisterns, and development of a midline shift. A white-matter focus of hyperintensity, consistent with brain edema, developed predominantly in the contralateral temporal lobe. During sustained inflation the volume of the balloon did not change and comprised 5 to 7% of total intracranial volume. During the same period the white-matter edema progressed further but no increased signal was revealed on DW images. After balloon deflation the brain reexpanded to the calvaria and imaging signs of raised intracranial pressure subsided. A cortical area of hyperintensity on T2-weighted images developed in the parietal lobe in the region of the former balloon compression. This area appeared bright on DW images, a finding that corresponded to an early cytotoxic edema. After deflation white-matter vasogenic edema in the temporal lobes regressed within 3 hours after reperfusion. The cortical edema in the parietal lobe and the ipsilateral basal ganglia became sharply demarcated. The histopathological results (that is, the extent of tissue damage) corresponded with findings of the authors' companion investigation, which appears in this issue.
Conclusions. Magnetic resonance imaging allows for a precise and sequential in vivo monitoring of a space-occupying epidural mass lesion and visualizes the time course of vasogenic and cytotoxic brain edema. This rodent model of an epidural mass lesion proved to be reproducible.
Painful human neuromas: a potential role for a structural transmembrane protein, ankyrin G
Authors: Kretschmer Thomas , Nguyen Doan H. , Beuerman Roger W. , Happel Leo T. , England John D. , Tiel Robert L. , Kline David G. 
Published: May 2009

Object. Severe nerve injury induces the formation of a neuroma. Some neuromas cause excruciating pain. Overexpression of Na+ channels leads to hyperexcitability and painful phenomena. Ankyrin G, a multifunctional transmembrane protein of the axolemma, might be a key protein in neuroma formation because it binds Na+ channels in the initial segments of a regenerating axon and links with neuronal cell adhesion molecules. The authors wanted to determine if ankyrin G could be detected in neuroma, and if present, whether there would be differences in distribution between nonpainful neuromas, painful neuromas, and normal nerve.
Methods. First, frozen sections of nine nerve specimens obtained from six patients (six nonpainful neuromas, one painful neuroma, and two normal nerves) were immunocytochemically screened for ankyrin G by using confocal laser scanning microscopy. Second, specimens from 29 patients (seven painful neuromas, 15 nonpainful neuromas, and seven normal nerves) were examined using immunoblot analysis for their ankyrin G content. Western blot analysis detected ankyrin G, which was visualized by applying the enhanced chemiluminescence technique. Computerized densitometry was used to quantitate ankyrin G expression by comparing band intensities. Normal nerve served as control. Neurofilament was used as a marker for nerve tissue content.
Ankyrin G could be detected and was found to be increased in neuromas. The mean band intensity values were 1838 for painful neuromas, 1166 for nonpainful neuromas, and 411 for normal nerves. In two cases the authors were able to compare specimens of painful neuroma and normal nerve from the same patient. The painful neuromas exhibited considerably higher levels of ankyrin G. Painful neuroma and normal nerve densitometry values were 499 and 165, respectively, for one patient, and 4254 and 821, respectively, for the other patient. Painful neuromas were also found to have higher neurofilament values than nonpainful neuromas.
Conclusions. Altered regulation of ankyrin G after nerve injury may lead to hyperexcitability and painful phenomena via clustering of Na+ channels. A propensity to overexpress ankyrin G after peripheral nerve trauma may turn out to be a factor in the development of painful neuromas and neuropathic pain. The relevant literature regarding the importance of ankyrin G for nerve regeneration and nerve membrane remodeling is reviewed.
Quantification of susceptibility artifacts produced on high-field magnetic resonance images by various biomaterials used for neurosurgical implants
Authors: Matsuura Hideki , Inoue Takashi , Konno Hiromu , Sasaki Makoto , Ogasawara Kuniaki , Ogawa Akira 
Published: May 2009

✓ Although various biomaterials such as ceramics or titanium alloy are widely used in neurosurgery, the susceptibility artifacts that appear around these materials cause problems when a magnetic resonance (MR) imager is used to assess lesions after surgery. The purpose of the present study was to quantify the susceptibility artifacts produced by various biomaterials used for neurosurgical implants.
Using a 3-tesla MR imaging unit, we obtained MR images of various biomaterials, including six types of ceramics, a cobalt-based alloy (Elgiloy), pure titanium, a titanium alloy, and stainless steel. All implants shared a uniform size and shape. In each image, a linear region of interest was defined across the center of the biomaterial in the transverse direction, and the diameter of the susceptibility artifact was calculated.
The ceramics produced a considerably smaller artifact diameter than those produced by other biomaterials. Among the types of ceramics, zirconia was found to produce the smallest artifact diameter. Among the remaining biomaterials, the diameters of the artifacts decreased in order from that associated with stainless steel to those associated with cobalt-based alloys, pure titanium, and titanium alloy. Little difference was observed between the artifact diameters associated with pure titanium and titanium alloy.
Ceramics are the most suitable biomaterials for minimizing artifacts in high-field MR imaging.
The impact of methicillin-resistant Staphylococcus aureus in a neurosurgical unit: a growing problem
Authors: Gnanalingham Kanna K. , Elsaghier Ashraf , Kibbler Christopher , Shieff Colin 
Published: May 2009

Object. Methicillin-resistant Staphylococcus aureus (MRSA) infection is a growing problem worldwide. To investigate the severity of the problem, the authors surveyed the incidence of MRSA colonization and infection in the neurosurgical unit at their institution.
Methods. Patients colonized or infected with MRSA who had been treated in the neurosurgical unit between 1993 and 1999 were retrospectively identified from laboratory records. There were 203 patients with MRSA-positive cultures, and the incidence of infection increased between 1993 (16 cases; 1.9% of admissions) and 1999 (60 cases; 6.7% of admissions). The mean duration of hospital stay was longer in patients with MRSA than in all patients treated in the unit (33.6 compared with 10.3 days, p < 0.001). Methicillin-resistant S. aureus was isolated from the nose in 89 patients, the throat in 79, the perineum in 52, surgical wounds in 16, sputum in 15, blood in 10, and from multiple sites in 69 patients. Fifty-six patients (28%) were infected with MRSA, and there were 15 deaths, of which three (20%) were likely to be due to the infection. The sources of MRSA included the neurosurgical ward in 84 patients, the intensive care unit in 28, other hospitals in 39, and the community in 17. The common strains of MRSA isolated were epidemic (E)MRSA-16 (110 cases) and EMRSA-15 (31 cases). The microorganism was eradicated in 16 cases, not eradicated in 20, and 167 patients were discharged from the hospital before eradication was achieved. All MRSA isolates were sensitive to vancomycin and teicoplanin and there was reduced sensitivity to mupirocin.
Conclusions. Infection with MRSA is a growing problem in the neurosurgical population, and most cases are hospital-acquired and are associated with longer hospital stays. Asymptomatic colonization by this organism is far more common than infection of the surgical wound, although there is still morbidity due to MRSA sepsis. Most patients with MRSA are discharged before eradication of infection is achieved, thus increasing the risk that the infection will spread in the community. Strict adherence to the basic principles of infection control is the key to eradication of MRSA.
Prognostic value of magnetic resonance imaging—guided stereotactic biopsy in the evaluation of recurrent malignant astrocytoma compared with a lesion due to radiation effect
Authors: McGirt Matthew J. , Bulsara Ketan R. , Cummings Thomas J. , New Kent C. , Little Kenneth M. , Friedman Henry S. , Friedman Allan H. 
Published: May 2009

Object. The prognostic value of differentiating between recurrent malignant glioma and a lesion due to radiation effect by performing stereotactic biopsy has not been assessed. Thus, this study was undertaken to determine such value.
Methods. Between 1995 and 2001, 114 patients underwent magnetic resonance (MR) imaging—guided stereotactic biopsy to differentiate lesions caused by a recurrence of malignant astrocytoma and by radiation effect. All patients had previously undergone tumor resection (World Health Organization Grade III or IV) followed by radiotherapy. Disease diagnosis based on biopsy and patient characteristics were assessed as predictors of survival according to results of a multivariate Cox regression analysis. The diagnosis determined with the aid of biopsy was compared with that established during a subsequent resection in 26 patients.
Survival following stereotactic biopsy was markedly increased in patients suffering from radiation effect compared with those harboring recurrent malignant glioma (p < 0.0001). In patients with radiation effect on biopsy, an increasing patient age (p < 0.05), having had two compared with one prior resection (p < 0.05), and a decreasing time from radiotherapy to biopsy (p < 0.001) were factors associated with decreased survival. Nevertheless, in patients with biopsy-defined radiation effect at second progression or with an age younger than 50 years the survival rate remained higher than that in patients with recurrent tumor on biopsy (p < 0.01). A biopsy-based diagnosis of radiation effect obtained less than 5 months after radiotherapy was not associated with an increased rate of patient survival compared with a diagnosis of recurrent malignant glioma on biopsy (p = 0.286). Eighty-six percent of lesions initially determined to be due to radiation effect on biopsy fewer than 5 months after radiotherapy were characterized as recurrent glioma by a mean of 11 months later. In contrast, only 25% of lesions initially diagnosed as attributable to radiation effect on biopsy more than 5 months after radiotherapy were classified as recurrent glioma a mean of 12 months later (p < 0.05).
Conclusions. With the aid of stereotactic biopsy the authors demonstrated prognostic significance in differentiating recurrent malignant astrocytoma from a lesion due to radiation effect in patients presenting more than 5 months after having undergone radiotherapy. In patients who presented earlier than 5 months after radiotherapy, radiation effect on biopsy was not associated with an improved rate of survival compared with that in patients harboring recurrent malignant astrocytoma.
Sex-related differences in patients with severe head injury: greater susceptibility to brain swelling in female patients 50 years of age and younger
Authors: Farin Azadeh , Deutsch Reena , Biegon Anat , Marshall Lawrence F. 
Published: May 2009

Object. The goal of this study was to study the influence of sex and age on factors affecting patient outcome in severe head injury.
Methods. Data from the prospectively conducted international trial of tirilazad mesylate in patients with head injury were analyzed retrospectively. Included were 957 patients, 23% of whom were female and all of whom were between the ages of 15 and 79 years. All patients presented with Glasgow Coma Scale (GCS) scores between 3 and 8 and evidence of structural brain damage and/or subarachnoid hemorrhage (SAH) on the initial CT scan. Frequencies of recognized risk factors, including brain swelling, intracranial hypertension, systemic hypotension, advanced age, SAH, and injury severity (based on GCS scores), as well as dichotomized Glasgow Outcome Scale (GOS) scores (good recovery or moderate disability compared with severe disability, persistent vegetative state, or death) obtained 6 months postinjury were compared between male and female patients.
Conclusions. Overall significantly greater frequencies of brain swelling and intracranial hypertension were found in female compared with male patients (35% compared with 24% [p < 0.0008] and 39 compared with 31% [p < 0.03], respectively). The highest rates were found in female patients younger than 51 years old (38% compared with 24% [p < 0.002] and 40% compared with 30% [p < 0.02], respectively, in male patients younger than 51 years of age). This effect was independent of injury severity (GCS) scores, which were not different in male and female patients. Female patients younger than 50 years tended to have worse outcomes, but the difference was not statistically significant. Thus, female patients who sustain severe head injury, especially (presumably) premenopausal ones aged 50 years and younger, are significantly more likely to experience brain swelling and intracranial hypertension than male patients with a comparable injury severity, suggesting that younger women may benefit from more aggressive monitoring and treatment of intracranial hypertension.
Traumatic subarachnoid hemorrhage on the computerized tomography scan obtained at admission: a multicenter assessment of the accuracy of diagnosis and the potential impact on patient outcome
Authors: Mattioli Cristina , Beretta Luigi , Gerevini Simonetta , Veglia Fabrizio , Citerio Giuseppe , Cormio Manuela , Stocchetti Nino 
Published: May 2009

Object. The goal of this study was fourfold: 1) to determine the incidence of traumatic subarachnoid hemorrhage (tSAH) in patients with traumatic brain injury (TBI); 2) to verify agreement in the diagnosis of tSAH in a multicenter study; 3) to assess the incidence of tSAH on the outcome of the patient; and 4) to establish whether tSAH itself leads to an unfavorable outcome or whether it is a sign of major brain trauma associated with severe posttraumatic lesions.
Methods. Computerized tomography (CT) scans obtained in 169 head-injured patients on admission to 12 Italian intensive care units during a 3-month period were examined. The scans were collected for neuroradiological review and were used for the analysis together with data from a multicenter database (Neurolink).
A review committee found a high incidence of tSAH (61%) in patients with TBI and a moderate agreement among centers (K = 0.57). Significant associations were observed between the presence and grading of tSAH and patient outcomes, and between the presence of tSAH and the severity of the CT findings. Logistic regression analysis showed that the presence of tSAH and its grading alone do not assume statistical significance in the prediction of unfavorable outcome.
Conclusions. Traumatic SAH frequently occurs in patients with TBI, but it is difficult to detect and grade. Traumatic SAH is associated with more severe CT findings and a worse patient outcome.
Aneurysmal subarachnoid hemorrhage in young adults
Authors: Ogungbo Biodun , Gregson Barbara , Blackburn Alison , Barnes Jane , Vivar Ramon , Sengupta Robin , Mendelow A. David 
Published: May 2009

Object. The authors reviewed the management protocols for young adults who presented with subarachnoid hemorrhage (SAH) at the Regional Neurosurgery Unit in Newcastle during a study period of 9 years. Aneurysmal SAH is uncommon in the age group selected (18–39 years) and, therefore, the performance of these patients has not been extensively reported in the literature. The authors also evaluated the good-grade rebleed rate (an index of management efficiency) in this cohort of patients.
Methods. The Newcastle neurosurgical unit serves a population of close to 3 million people, and an average of 180 patients with SAH are seen each year. The majority of patients are transferred from other hospitals in the region. This study includes patients admitted between January 1990 and December 1998. A total of 1609 patients were admitted during this period, of whom 295 (18.4%) between the ages of 18 and 39 years constituted the study population of young adults.
Two hundred ninety-five young adults presented with SAH; 181 (61.4%) were women and 114 (38.6%) were men, a ratio of 3:2. Of 246 patients in whom this value was recorded, 15 (6.1%) presented with a history of hypertension, and there was an association between hypertension and the occurrence of multiple aneurysms (Fisher two-tailed exact test, p = 0.008). Thirty-five patients (11.9%) presented with a hematoma on computerized tomography scans; of these, 20 (57%) were women and 15 were men.
In six patients the lesion had rebled before treatment. The good-grade rebleed rate was three (1.7%) of 178. The overall favorable outcome rate was 83.8% (Glasgow Outcome Scale [GOS] 4 and 5) and unfavorable outcome occurred in 16.2% (GOS 1–3), with a total of 40 deaths in this group (13%). Age had no influence on outcome in young adults. Comparing the outcome at discharge with the follow-up evaluation at 6 months revealed that patients in the moderate and severe disability groups continued to improve and many achieved good recovery.
Conclusions. In this report the authors detail the outcome of a large number of young adults with SAH. The incidence of SAH was higher in the female population, although the ratio was not as high as previously reported. The authors have also demonstrated a progressive increase in the incidence of aneurysmal SAH with age, even in young adults. Hypertension but not age influenced the occurrence of multiple aneurysms. The good-grade rebleed rate is low, although it is not zero. Generally, a satisfactory outcome was obtained and significant continuing improvements were noted between discharge and follow-up evaluation. This reflects the power of recovery in young adults. These are people whose economic productivity and fertility are at peak levels and therefore the financial and social burden occasioned by less-than-perfect outcomes is large.