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Results for “SUBARACHNOID SPACE”

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At least 109 records · Page 6Linked to original sources
PubMed1991

Local and diffuse spread of juvenile cerebellar astrocytomas in subarachnoid space. Light and electron microscopic study.

Based on 5 cases of juvenile astrocytomas the unusual behaviour of this type of tumor is described. It is expressed by local and/or diffuse spread of the neoplasms in the subarachnoid space of the brain hemispheres, cerebellum and spinal cord. The light and electron microscopic examinations have revealed the morphological features of well differentiated tumors of astrocytic origin and of fibrillary type which in a great number of cases have a favourable prognosis. The cause of break through into the subarachnoid space, despite its morphology which indicates on a high degree of differentiation of the tumors, is not known. The relation of primary to secondary infiltration of the subarachnoid space or of the leptomeninges is discussed.

Astrocytes↗
PubMed1991

Distribution of catheter-injected local anesthetic in a model of the subarachnoid space.

Maldistribution of local anesthetic administered through a subarachnoid catheter recently has been implicated as a possible cause of sacral root injury. To examine subarachnoid distribution of catheter-injected local anesthetic, we constructed a model of the subarachnoid space and administered solutions containing lidocaine and methylene blue through sacrally directed catheters. We studied three catheters: a 28-G endport, a 20-G endport, and a 20-G multiple sideport. To determine the injection rates to be used, ten clinicians were observed while they performed mock subarachnoid injections: the mean (+/- standard deviation) "normal" injection times for the 28-G and 20-G catheters were 52.6 +/- 17.2 and 11.9 +/- 7.2 s, respectively. The correlation coefficient for lidocaine concentration estimated by methylene blue spectrophotometric absorbance and measured by immunoassay was 0.977. Administration of hyperbaric local anesthetic through a sacrally directed catheter resulted in restricted distribution of anesthetic with a relatively high peak concentration. Rate of injection was a critical factor affecting distribution; faster injections tended to distribute solution more uniformly and to a higher segmental level, resulting in substantially lower peak concentrations. When catheters were injected at clinically relevant rates, the 28-G catheter produced the greatest degree of maldistribution; this difference appeared to be primarily a function of flow rate. Differences in peak lidocaine concentration between the two 20-G catheters were neither large nor consistent. However, despite sacral placement, the multiple-sideport catheter distributed anesthetic toward "higher" spinal segments more consistently. Distribution was more favorable when the injected solution was less dense (closer to isobaric).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Spinal↗
PubMedDate not supplied

Catheterization of the subarachnoid space in rabbits using a Vascular Access Port.

A surgical technique allowing chronic access to the subarachnoid space in unanesthetized rabbits was devised using the Vascular Access Port system. Instrumentation provides the investigator with a method of measuring intracranial pressure and sampling cerebrospinal fluid in awake rabbits. The catheter is introduced into the dorsal cervical subarachnoid space at the C4-C5 intervertebral space via dorsal laminectomy and passed cranially into the cisterna magna. The access port is subcutaneously implanted in the dorsal thoracic region between the scapulas. This system reduces the potential for infection, is not easily removed by the animal, and is relatively easy to access with minimal discomfort for the animal.

Animals↗
PubMed1978

Normal computed tomography anatomy of the suprasellar subarachnoid space.

To assess normal variants of the suprasellar subarachnoid space, 680 CT scans were reviewed. Three main configurations with subgroups of the suprasellar cistern could be found: a large hexagon (60.7%), a small hexagon (17.6%) and a small tetragon (21.7%). In about a third of the scans, the region of interest was not visualized sufficiently. The large variety of CT appearance of the normal suprasellar space could be attributed to anatomical and technical reasons. To exclude a suprasellar mass lesion it is necessary to be aware of the anatomical variations, investigate the suprasellar region with additional intermediate cuts or contrast enhancement and define the cut level and osseous structures by a lateral skull radiograph.

Humans↗
PubMed2003

Altered subarachnoid space compliance and fluid flow in an animal model of posttraumatic syringomyelia.

STUDY DESIGN: A histologic study of cerebrospinal fluid tracers in Sprague-Dawley rats undergoing lumboperitoneal shunt insertion in the excitotoxic animal model of posttraumatic syringomyelia (PTS). OBJECTIVES: To determine the effects of cerebrospinal fluid (CSF) diversion from the subarachnoid space on perivascular flow (PVS) and syrinx formation in posttraumatic syringomyelia. SUMMARY OF BACKGROUND DATA: In an animal model of PTS, fluid enters syringes from the subarachnoid space via perivascular spaces. Preferential PVS flow occurs at the level of the syrinx. It has been suggested that arachnoiditis predisposes to posttraumatic syringomyelia formation by obstructing subarachnoid cerebrospinal fluid flow and enhancing perivascular flow. MATERIALS AND METHODS: Thirty-two male Sprague-Dawley rats were investigated using the CSF tracer horseradish peroxidase (HRP), the excitotoxic model of PTS, and lumboperitoneal shunt insertion. Five experimental groups consisted of normal controls, syrinx only and shunt only controls, and shunt insertion before or after syrinx formation. In all groups except normal controls, CSF flow studies were performed 6 weeks after the final intervention. Grading scales were used to quantify HRP staining. RESULTS: All excitotoxic model animals formed syringes. Perivascular flow was greatest at the level of the syrinx. Cerebral cortex perivascular flow was significantly reduced after shunt insertion in animals with a syrinx (P < 0.05). Shunt insertion did not alter syrinx length or size. There were no significant differences between shunt and syrinx first groups. CONCLUSIONS: Increasing caudal subarachnoid space compliance with a shunt does not affect local CSF flow into the spinal cord and syrinx. These results suggest that localized alterations in compliance, as opposed to obstruction from traumatic arachnoiditis, may act as an important factor in syrinx pathogenesis.

Animals↗
PubMed1997

Attenuation of formalin pain responses in the rat by adrenal medullary transplants in the spinal subarachnoid space.

Previous reports have indicated that the implantation of adrenal medullary chromaffin cells into the spinal subarachnoid space can reduce both acute and chronic pain in several animal models. Recent findings suggest that acute and chronic pain alleviation may be mediated by distinct mechanisms. Since the formalin response is composed of an acute and tonic phase which can be pharmacologically distinguished, the ability of adrenal medullary implants to alter these responses was assessed. In rats with adrenal medullary transplants, both phases of the formalin response were attenuated, in contrast to control implanted animals. Suppression of the acute phase by adrenal medullary implants was reversed by the opiate antagonist naloxone, and partially reversed by the alpha-adrenergic antagonist phentolamine, suggesting that opioid peptides and catecholamines released by the implanted chromaffin cells contribute to the observed antinociception. However, neither antagonist altered the antinociceptive effects of adrenal medullary implants on the tonic phase of the formalin response. These results indicate that adrenal medullary implants in the spinal subarachnoid space alleviate acute and tonic pain via distinct pharmacologic mechanisms.

Adrenal Medulla↗
PubMed2006

Ultrasonographic measurement of subarachnoid space in normal term newborns.

This study was conducted in order to assess the normal range of subarachnoid space width in healthy term newborns. A total of 230 healthy newborns were evaluated within the first 28 days of life. Measurements were correlated with body weight, height and head circumference. Mean measurements for falx-cortex and craniocortical widths and the correlations are given in tables. Subarachnoid space widths increased as weight, height and head circumference increased and the correlation was statistically significant.

Body Height↗
PubMed1998

Decoy administration of NF-kappaB into the subarachnoid space for cerebral angiopathy.

Subarachnoid hemorrhage (SAH), encephalitis, meningitis, and autoimmune diseases sometimes lead to cerebral angiopathy, characterized specifically by narrowing of vessels, morphological changes in the structure of vessel walls, and a concomitant decrease in cerebral blood flow. Many patients also develop delayed ischemic neurological deficits. Thus, preventing vascular reactions is of paramount importance in treating SAH. Although cerebral vasospasm has some relationship with the inflammatory reaction of major cerebral vessels against the autologous blood, and many trials have attempted to prevent angiopathy after SAH, an effective treatment has not yet been established. The purpose of this article is to evaluate the preventive effect of nuclear factor KB (NF-kappaB) decoy oligo-DNA after SAH; since NF-kappaB is closely related to inflammation. In the rabbit angiopathy model after SAH, we evaluated the effectiveness of the decoy oligo-DNA using the angiographic (digital subtraction angiography) and histological (hematoxylin-eosin and Masson's trichrome staining) methods. Moreover, a gel-shift assay for NF-kappaB was also performed in order to evaluate the activity of NF-kappaB. We describe a new concept for treating cerebral angiopathy after SAH and for successfully inhibiting cerebral vasospasm and morphological changes in vessel walls in a rabbit model. In this treatment, we used synthetic double-strand oligo-DNA with a high affinity for transcription factor NF-kappaB, and cationic liposome complex administered through the cerebrospinal fluid.

Animals↗
PubMed1996

Humoral and cellular immune response within the subarachnoid space of patients with neurocysticercosis.

To study the immune response within the subarachnoid space in patients with neurocysticercosis, we measured the cerebrospinal fluid contents of immunoglobulins A, E, G, and M in 38 patients and the contents of the proinflammatory cytokines TNF-alpha, IL-1b, IL-6 and IFN-gamma in 17 patients. The same measurements were made in 30 neurological patients without inflammatory or immune-mediated disorders. Each immunoglobulin and cytokine, including the gender and age of the patient, was compared by multiple regression analysis with the CSF contents of cells, protein and ELISA for cysticercal antigens. A direct correlation was found of IgM with cell content (p < 0.058) and with ELISA values (p < 0.027); of age with protein content (p < 0.006); of IL-6 with protein content (p < 0.018) and of IL-1b with ELISA values (p < 0.004). An inverse correlation was found of glucose with ELISA values (p < 0.008). A complex function of the immune response within the subarachnoid space was observed: mean values of IgG, IgM, IgE and interleukins 1b and 6 were increased, whereas values of IgA, TNF-alpha and IFN-gamma were similar to those of controls.

Antigens, Helminth↗
PubMed1982

T-dependent antigens are more immunogenic in the subarachnoid space than in other sites.

Systemic antibody responses were compared in mice injected with antigens into the subarachnoid space (SAS) and into conventional sites. Introduction of T-dependent antigens into the SAS induced higher systemic antibody responses than injections into any other sites. This applied to both soluble and particulate antigens and was more apparent in secondary than in primary responses. The effect was not observed with a T-independent antigen and not consistently with high doses of sheep red blood cells (SRBC). It was concluded that the subarachnoid space is a highly efficient site for the induction of systemic antibody production, in particular to low amounts of T-dependent antigens.

Animals↗
PubMed2006

Subdural hematomas in infants with benign enlargement of the subarachnoid spaces are not pathognomonic for child abuse.

BACKGROUND AND PURPOSE: Patients who have benign enlargement of the subarachnoid spaces (BESS) have long been suspected of having an increased propensity for subdural hematomas either spontaneously or as a result of accidental injury. Subdural hematomas in infants are often equated with nonaccidental trauma (NAT). A better understanding of the clinical and imaging characteristics of subdural hematomas that occur either spontaneously or as a result of accidental trauma may help distinguish this group of patients from those who suffer subdural hematomas as a result of NAT. The purpose of this study is to describe the clinical and imaging characteristics of subdural hematomas that occur either spontaneously or as a result of accidental injury in infants with BESS. METHODS: We conducted a retrospective review of all patients with BESS complicated by subdural hematomas evaluated at a single institution from 1998 to 2004. Data concerning the patient's clinical presentation, physical findings, imaging, and management are described. RESULTS: During the study period, 7 patients with BESS complicated by subdural hematoma were identified. Their mean age at identification of the subdural hematoma was 7.4 months of age. In 5 cases, there was no recognized trauma before identification of the subdural hematoma. In 3 cases, baseline CT or MR imaging was available, showing prominent subarachnoid spaces without any evidence of subdural hemorrhage. CONCLUSION: Although suspicious for NAT, subdural hematomas can occur in children either spontaneously or as a result of accidental trauma. Caution must be exercised when investigating for NAT based on the sole presence of subdural hematomas, especially in children who are otherwise well and who have BESS.

Accidents, Traffic↗
PubMed2000

Theoretical foundations for noninvasive measurement of variations in the width of the subarachnoid space.

Numerical modeling was used for the theoretical analysis of the propagation of optical radiation in the tissues of the human head, generated by a single source placed on the surface of the scalp. Of special interest and importance is the propagation of radiation within the layer of cerebrospinal fluid contained in the subarachnoid space (SAS), which is the only low absorption/high transmittance medium whose width can vary rapidly. Qualitative and quantitative assessment of changes in propagation of radiation within the SAS could become a source of information on changes in the geometry of this anatomical compartment playing a crucial role in cranio-spinal physiology and pathology. Essential for the idea of the possible noninvasive assessment of changes in width of the SAS by an optical method is the dependence of intensity of radiation reaching a photodetector located at a certain distance from the source on changes in the width of this fluid layer, which acts like a biological optical waveguide. Monte Carlo modeling and numerical analysis confirmed the feasibility of assessing changes in the width of the subarachnoid space optically. Presented here are details of the Monte Carlo simulation of light propagation in the tissues of human head and the results of such simulation as a function of the width of the subarachnoid space, calculated for different distances between the source and detector and for a few selected values of bone thickness. Results of numerical modeling were then compared with those of experiments on a mechanical-optical model.

Adolescent↗
PubMedDate not supplied

Elimination of metrizamide from the spinal subarachnoid space: a study of patients with abolished intracranial circulation.

Two absorptive pathways for contrast media injected into the lumbar subarachnoid space have been postulated: (1) through the intracranial parasagittal arachnoid granulations and (2) direct absorption through the spinal arachnoid villi into the blood. To study the capacity of the spinal absorptive pathway, serial measurements of metrizamide concentrations in blood serum and urine were obtained before and after lumbar intrathecal injection of contrast medium in four patients with arrested intracranial blood circulation ("brain death") and intracranial pressure exceeding systolic blood pressure who had no circulation of cerebrospinal fluid from the spinal subarachnoid space to the parasagittal arachnoid granulations. These measurements indicated a high capacity of the spinal absorptive pathway for metrizamide elimination.

Blood-Brain Barrier↗
PubMed1996

Study of subarachnoid spaces in children with idiopathic mental retardation.

The aim of this study was to assess quantitatively the size of the subarachnoid space in children with "idiopathic" mental retardation. The extent of various cerebrospinal fluid compartments was measured in 106 brain computed tomographic examinations of children with idiopathic mental retardation, and the results were compared with the corresponding normative data. The third ventricle was enlarged in 77% of the cases. A mild degree of diffuse widening of the subarachnoid spaces was found in about 30% of the patients. These morphologic alterations are additional observations supporting the hypothesis that "idiopathic" mental retardation has a biologic basis.

Adolescent↗
PubMed2002

Decompression of the spinal subarachnoid space as a solution for syringomyelia without Chiari malformation.

STUDY DESIGN: Review and analysis of seven cases of syringomyelia treated surgically. OBJECTIVE: To demonstrate the beneficial role of decompressive surgery for the altered cerebrospinal fluid (CSF) flow dynamics in syringomyelia not associated with Chiari I malformation. A comparison between the pre- and post-operative syrinx size and CSF flow in the subarachnoid space was made using cine-mode magnetic resonance imaging (cine-MRI) and then correlated with clinical improvement. SETTING: University Hospital, Seoul, Korea. METHODS: Conventional spinal MRI and cine-MRI were performed in the region of CSF flow obstruction preoperatively in seven patients with syringomyelia not associated with Chiari I malformation. The group consisted of one case of syrinx with post-traumatic compression fracture, one case of post-traumatic arachnoiditis, two cases of holocord syrinx associated with hydrocephalus without Chiari malformation, one case of syrinx with post-traumatic pseudomeningeal cyst, one case of post-laminectomy kyphosis-associated syringomyelia and one case of post-tuberculous arachnoiditis syringomyelia. Based on the preoperative cine-MRI, the types of surgery appropriate to correct the CSF flow obstruction were chosen: decompressive laminectomy-adhesiolysis and augmentation duraplasty in arachnoiditis cases, ventriculoperitoneal shunt for hydrocephalus, cyst extirpation in pseudomeningeal cyst and both anterior and posterior decompression-fusion in the case of post-laminectomy kyphosis. A syrinx-draining shunt operation was performed in three cases; where the syringomyelia was associated with post-traumatic compression fracture refractory to a previous decompression, where hydrocephalus was present in which the decompression by ventriculoperitoneal shunt was insufficient and where post-traumatic arachnoiditis was present in which the decompression was impossible due to diffuse adhesion. Change in syrinx size was evaluated with post-operative MRI in all seven cases and restoration of flow dynamics was evaluated with cine-MRI in three of the cases, two patients with clinical improvement and one patient with no change of clinical status, respectively. RESULTS: Four out of seven patients showed symptomatic improvement after each decompressive operation. In the remaining three cases, reconstruction of the spinal subarachnoid space was not possible due to diffuse adhesion or was not the main problem as in the patient with syrinx associated with hydrocephalus who had to undergo a shunt operation. One of these three patients showed clinical improvement after undergoing syringosubarachnoid shunt. A decrease of syrinx size was observed in only two out of the five patients who showed clinical improvement after treatment. Of these five patients, two patients underwent post-operative cine-MRI and the restoration of normal CSF flow dynamics was noted in both patients. Of the remaining two patients, one underwent post-operative cine-MRI and there was no change in the CSF flow dynamics evident. CONCLUSION: These results suggest that the restoration of CSF flow dynamics between the syrinx and the subarachnoid space by decompressive operation is more effective than simple drainage of the syrinx cavity itself in the treatment of syringomyelia without Chiari malformation.

Adolescent↗
PubMed1991

[The neuroevolutionary profile of the nursing infant with macrocephaly and benign enlargement of the subarachnoid space].

With the purpose of studying the neuroevolutionary prognosis of children with macrocephaly (percentile 95) and the widening of the subarachnoid space, identified using head CAT scans-five cases were selected from the Pediatric-Neurology Department from the Teaching Regional Hospital of Trujillo-Perú, seen during January 1983 and January 1988 with a follow-up of 1 and 1/2 and 3 years. All of the children showed an abnormal separation of the frontal subarachnoid space, interhemispheric fissure and Silvio incision without ventriculomegaly o a minimal dilation of the ventricular system. Through neurological evaluation and the Denver Development Test, in all cases except one, a characteristic pattern of hypotony and gross motor retardation were seen during the first year of life, which was modified towards normality during the following months until the age of 24 to 40 months. This findings suggest the good prognosis and benign nature of this condition which can be spontaneously resolved and apparently related to benign family macrocephaly.

Brain↗
PubMedDate not supplied

Elimination of aqueous myelographic contrast media from the subarachnoid space.

Elimination of aqueous contrast media from the lumbar subarachnoid space was measured. Iodine concentrations in serum and cisterna magna cerebrospinal fluid were studied in animals undergoing myelography with metrizamide, iocarmate, Iopamidol, or P-297. We found that all four contrast media were eliminated rapidly into the serum and urine, and transported slowly into the basal cisterns.

Animals↗