A 72-year-old man presented with an extremely rare case of symptomatic isolated lumbosacral interdural arachnoid cyst manifesting as pain and weakness in the right buttock and lower extremity that had aggravated for 2 weeks. Although the surgical strategy for the interdural cyst was not complicated, the origination of the cyst was not clearly understood. Surgery found an isolated membrane of the cyst inside double-layered dura without communication with the intact arachnoid membrane. Cerebrospinal fluid with hemorrhage accumulated within the interdural cyst indicated recent bleeding into the cyst. Our experience suggests that this cyst was congenital based on the surgical results and imaging studies. (+info)
Anatomic relations of the arachnoidea around the pituitary stalk: relevance for surgical removal of craniopharyngiomas.
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Ultrastructural changes in the Liliequist membrane in the hydrocephalic process and its implications for the endoscopic third ventriculostomy procedure.
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Modified three-dimensional brain model for study of the trans-sylvian approach.
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The trans-sylvian approach is one of the most frequently employed neurosurgical procedures, but it is difficult for medical students to understand the approach stereoscopically. A three-dimensional model equipped with an arachnoid membrane and sylvian vein was developed which can be repeatedly used to simulate surgery for the education of medical students and residents in the trans-sylvian approach. The model was prepared using existing models of the skull bone, brain, and cerebral artery. Polyvinylidene chloride film, commonly used as plastic wrap for food, was adopted for the arachnoid membrane, and wetted water-insoluble tissue paper for the arachnoid trabeculae. The sylvian vein was prepared by ligating woolen yarn with cotton lace thread at several sites. Students and residents performed the trans-sylvian approach under a microscope, and answered a questionnaire survey. Using this model, simulation of division of the arachnoid membrane and arachnoid trabeculae, and dissection of the sylvian vein was possible. In the questionnaire, the subjects answered 8 questions concerning understanding of the stereoscopic anatomy of the sylvian fissure, usefulness of the simulation, and interest in neurosurgical operation using the following ratings: yes, very much; yes; somewhat; not very much; or not at all. All items rated as 'yes, very much' and 'yes' accounted for more than 70% of answers. This model was useful for medical students to learn the trans-sylvian approach. In addition, repeated practice is possible using cheap materials, which is advantageous for an educational model. (+info)
Tethered cord syndrome in childhood: special emphasis on the surgical technique and review of the literature with our experience.
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Chronic subdural hematoma associated with arachnoid cyst. Two case histories with pathological observations.
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Arachnoid cysts are well known to induce chronic subdural hematoma (CSDH) after head injury. However, histological observations of the arachnoid cyst and hematoma membrane have only been rarely described. An 8-year-old boy and a 3-year-old boy presented with CSDH associated with arachnoid cyst. Surgical removal of the hematoma and biopsy of the hematoma membrane and cyst wall were performed. Clinical courses were good and without recurrence more than 1.5 years after surgery. Histological examination suggested that the cysts did not contribute to hematoma development. Pediatric hematoma membranes, similar to adult hematoma membranes, are key in the growth of CSDH. Therefore, simple hematoma evacuation is adequate as a first operation for CSDH associated with arachnoid cyst. (+info)
Morphine and alfentanil permeability through the spinal dura, arachnoid, and pia mater of dogs and monkeys.
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Little information exists about which spinal meninx is the principal permeability barrier between the epidural space and the spinal cord or about what physicochemical properties of drug molecules govern their meningeal permeability. To better understand these aspects of epidural pharmacokinetics, the authors measured the permeability of morphine and alfentanil through the different components of the spinal meninges-dura mater, arachnoid mater, and pia mater-of dogs and monkeys in vitro. Live meningeal tissue from either species (dura mater alone, pia mater alone, or intact dura-arachnoid-pia) was placed between two fluid reservoirs of a temperature-controlled diffusion cell. The permeability of the tissues to each opioid was determined by placing the opioid in one of the reservoirs of the diffusion cell and measuring the rate at which the drug diffused through the tissue and appeared in the second reservoir. The arachnoid mater was found to be the major meningeal diffusion barrier between the epidural space and the spinal cord. Alfentanil was 3.7 times more permeable than morphine through all three meninges, suggesting that increased lipid solubility increases meningeal permeability. However, neither lipid solubility nor molecular weight adequately explained the difference in permeability between morphine and alfentanil. The authors conclude that this in vitro model has significant utility for studies aimed at predicting in vivo meningeal permeability and hence the potency and rapidity of action of any opioid administered by the epidural route. (+info)