Overlying Dura Mater Research Articles

Investigations of the subarachnoid space as a potential link between aura and headache in migraine: A case-control MRI study

Background The connection between migraine aura and headache is poorly understood. Some patients experience migraine aura without headache, and patients with migraine aura with headache commonly experience milder headaches with age. The distance between the cerebral cortex and the overlying dura mater has been hypothesized to influence development of headache following aura. We tested this hypothesis by comparing approximated distances between visual cortical areas and overlying dura mater between female patients with migraine aura without headache and female patients with migraine aura with headache. Methods Twelve cases with migraine aura without headache and 45 age-matched controls with migraine aura with headache underwent 3.0 T MRI. We calculated average distances between the occipital lobes, between the calcarine sulci, and between the skull and visual areas V1, V2 and V3a. We also measured volumes of corticospinal fluid between the occipital lobes, between the calcarine sulci, and overlying visual areas V2 and V3a. We investigated the relationship between headache status, distances and corticospinal fluid volumes using conditional logistic regression. Results Distances between the occipital lobes, calcarine sulci and between the skull and V1, V2 and V3a did not differ between patients with migraine aura with headache and patients with migraine aura without headache. We found no differences in corticospinal fluid volumes between groups. Conclusion We found no indication for a connection between visual migraine aura and headache based on cortico-cortical, cortex-to-skull distances, or corticospinal fluid volumes overlying visual cortical areas. Longitudinal studies with imaging sequences optimized for measuring the cortico-dural distance and a larger sample of patients are needed to further investigate the hypothesis.

Intracranial subdural osteoma

Subdural osteomas are extremely rare benign neoplasms. Here, we report the case of a 35-year-old female patient with a right frontal and parietal subdural osteoma. The patient presented with a 2-year history of intermittent headache and fatigue. Computerized tomography (CT) scan showed a high-density lesion attached to the inner surface of the right frontal and parietal skull. Magnetic resonance imaging (MRI) demonstrated T1 hyperintensity and T2 hypointensity of the lesion. Intraoperatively, the hard mass was located in subdural space and attached to the dura mater. Histopathological examination revealed lamellated bony trabeculae lined by osteoblasts and the intertrabecular marrow spaces occupied by adipose tissue. The patient underwent neurosurgical resection and recovered without complication. Surgical excision is recommended to extract the symptomatic lesions with overlying dura mater.

Dissection of the Trigeminal Ganglion of Nonrodent Species Used in Toxicology Studies.

The ganglion of the trigeminal (V cranial) nerve is generally sampled at necropsy in nonrodent toxicology studies only when somatic or autonomic peripheral nervous system toxicity is suspected. The ganglion is far more difficult to locate in nonrodents than in rats and mice, and suitable methods to dissect it have been described only for swine. The trigeminal nerve caudal to the ganglion passes through a canal, roofed by bone in dogs and rabbits and by a tough layer of dura mater in swine and nonhuman primates. The ganglion is partly or wholly obscured by overlying dura mater. Of the 3 intracranial branches of the nerve, the ophthalmic is delicate and the maxillary and mandibular have extremely short courses within the cranial cavity. Methods that are practical in routine toxicologic pathology for the dissection of the ganglion in nonrodent laboratory species are illustrated and relevant species differences in the anatomy of the intracranial part of the trigeminal nerve are highlighted.

Cerebrospinal fluid spaces between intracranial venous sinuses and overlying dura mater: magnetic resonance imaging.

Purpose The intracranial venous sinuses are thought to lie interdurally, circumferentially contacting the dura maters. There has been no report documenting the cerebrospinal fluid spaces intervening between the venous sinuses and overlying dura mater. Here, we explored such structures using magnetic resonance imaging. Methods A total of 206 patients underwent magnetic resonance imaging with a T2-weighted or constructive interference steady-state sequence. Imaging data were analysed on a workstation. Results The peri-superior sagittal sinus cerebrospinal fluid spaces were identified in 100% of 133 patients who underwent coronal and sagittal T2-weighted imaging and in 98.6% of 73 with a constructive interference steady-state sequence. Among the 205 patients, the cerebrospinal fluid spaces were distributed over the frontoparietal region in 84% and the parietal region in 16%. On sagittal sections performed for 58 patients, the cerebrospinal fluid spaces were identified between the superior sagittal sinus and overlying dura mater. The peri-sinus spaces were found in 91% of the identified transverse sinuses, 29% of the straight and 70% of the occipital sinuses. The peri-superior sagittal sinus cerebrospinal fluid spaces were classified into five distinct appearances. The circumferential type was the most predominant and was found in 68.7%, followed by lateral in 10.2%, lateral plus inferior in 7.5%, lateral plus superior in 6.8% and superior in 6.8%. Conclusions The intracranial venous sinuses do not circumferentially contact with the dura maters. Instead, they are adjacent to the cerebrospinal fluid spaces intervening between the walls and overlying dura maters. These spaces are critical when considering tumour extensions contralateral to the superior sagittal sinus and safe surgical manoeuvres around it.

Strategy in Front of Complex Infected Cranial Defects Overlying Dura Mater. Feasibility and Safety of Negative Pressure Wound Therapy

Although rare, large cranial infected defects are challenging for practitioners, especially when the dura mater is involved. These complex full-thickness wounds (scalp, bone, and dura mater) commonly occur after surgery, trauma or failed reconstructive procedures. Many patients are poor candidates for immediate reconstruction because of original pathology, patient's general state, previous radiotherapy, which compromises the locally available tissue, depth of the sepsis. For these challenging patients, a two-step procedure (cleanliness then reconstruction) has to be proposed. Recently, few authors report the use of negative pressure wound therapy, NPWT, in association with a first-step cleanliness surgery with encouraging results. Methods: We report three consecutive cases with standardized two-step procedure for complex full-thickness cranial wounds. First step is a cleanliness surgery associated with NPWT using a continue negative pressure ranging from 25 to 75 mm Hg. Safety of NPWT protocol is evaluated by neuropsychological and clinical examination. A second step for reconstruction is then performed. Results: Good outcomes were achieved in all cases without any complication due to NPWT with a 9-month follow-up. No significant difference was found between neuropsychological examination with or without NPWT. Conclusion: NPWT is a safe procedure optimizing local wound conditions for poor candidates for immediate reconstruction in complex infected cranial defects overlying the dura mater.

Intervertebral Disk Disease With Spinal Cord Penetration in a Yucatan Pig

A 9-month-old female Yucatan pig was euthanized after acute onset of paraplegia. Gross and microscopic examination revealed dorsal dissection of the nucleus of the L2-L3 intervertebral disk through the annulus fibrosus, extrusion of nucleus pulposus material through the overlying dura mater and into the spinal cord, and associated acute spinal hemorrhage and necrosis. This is, to the authors' knowledge, the first reported case of intervertebral disk disease in swine.

Recurring Intracranial Malignant Peripheral Nerve Sheath Tumor: Case Report and Systematic Review of the Literature

To report the clinical presentation and management of an intracranial frontoparietal malignant peripheral nerve sheath tumor (MPNST) and its recurrence in a 6-year-old girl, along with a systematic review of the literature. A previously healthy 6-year-old girl presented with severe signs of increased intracranial pressure. Magnetic resonance imaging (MRI) revealed a large heterogeneously enhancing mass at the right frontoparietal convexity. The tumor was completely removed, the histological diagnosis was MPNST, and the patient underwent adjuvant radio- and chemotherapy. Fifteen months later, MRI revealed a small local recurrence. After upfront chemotherapy, the recurrence was removed in a radical, ie, true oncological, neuronavigationally guided, en bloc resection, including approximately 1 cm surrounding gray and white matter and overlying dura mater. Neuropathological examination revealed tumor-free margins. The patient again received adjuvant chemotherapy. Four years after diagnosis and 20 months after cessation of adjuvant therapy, there are no signs of tumor recurrence. The literature search resulted in 17 cases of intracranial MPNSTs not associated with cranial nerves. Despite macroscopically complete resection in many cases and adjuvant radio- and chemotherapy, overall survival was poor, with only 5 patients still alive upon publication (including the current patient). Intracranial MPNSTs not associated with cranial nerves are extremely rare and highly malignant tumors with poor overall survival, probably because of infiltrating growth into surrounding brain tissue. We therefore advocate consideration of nonconventional true oncological en bloc resection when approaching this rare tumor or its recurrence.

Focal Idiopathic Hypertrophic Pachymeningoencephalitis

Cranial pachymeningitis is typically a diffuse granulomatous disease that involves the dura mater extensively without intra-axial involvement. We report a rare case of focal idiopathic hypertrophic pachymeningoencephalitis (IHP) focally affecting the right parietal dura mater and adjacent parietal lobule. A 43-year-old male suffered from acute onset of rhythmic twitching over the left abdominal muscles that had persisted for more than 4 hours. Neurologic examination revealed mild weakness and impaired sensation in the left lower limb. Electroencephalography disclosed active focal spikes in the right parietal region and brain magnetic resonance imaging showed a well-enhanced lesion involving the right parietal lobe and its overlying dura mater. Surgical removal of the lesion revealed infiltration by abundant chronic inflammatory cells without granuloma formation, caseous necrosis or vasculitis. After surgery, the patient was treated with steroid, which was tapered off 5 months later. Serial magnetic resonance imaging follow-up revealed that the parenchymal mass and perifocal edema had completely disappeared 6 months after the operation. We suggest that early recognition of this rare IHP, together with proper surgical intervention and concomitant steroid therapy, may be beneficial for long-term remission.

Eliminating the effect of epidural fat during dorsolumbar epidural analgesia in cattle

ObjectiveTo compare the distribution of new methylene blue (NMB) solution injected into either the subperiosteal space or under the epidural fat at the first and second lumbar vertebral interspace in cattle. Study designProspective experimental study. Sample populationNine nonpregnant cows. MethodsNeedles were advanced towards the first interlumbar epidural space using a dorsal mid-line approach. Upon confirmation of successful penetration of the ligamentum flavum, group 1 received 5 mL of 0.12% NMB in 0.9% saline. In group 2, the needle was slowly advanced a further 7–10 mm to ensure injection under the epidural fat; the same dose was injected. The extent of cranial and caudal migration of dye, as indicated by staining of epidural fat and the dura mater was measured. ResultsIn group 1 (n = 4), NMB solution migrated only between the periosteum and the epidural fat. There was unilateral distribution in two cows. In contrast, there was no difference between left- and right-sided distribution in group 2 (n = 5), and the NMB solution migrated only between epidural fat and the dura mater. Although the dura mater was not penetrated in any animal of group 2, the dorsal roots were slightly stained and the overlying dura mater was heavily stained in these animals. Conclusions and clinical relevanceVariation in distribution of local anaesthetic solution can probably be overcome by deeper needle penetration of the epidural fat.

Mechanical strain affects dura mater biological processes: implications for immature calvarial healing.

The human brain grows rapidly during the first 2 years of life. This growth generates tensile strain in the overlying dura mater and neurocranium. Interestingly, it is largely during this 2-year growth period that infants are able to reossify calvarial defects. This clinical observation is important because it suggests that calvarial healing is most robust during the period of active intracranial volume expansion. With a rat model, it was previously demonstrated that immature dura mater proliferates more rapidly and produces more osteogenic cytokines and markers of osteoblast differentiation than does mature dura mater. It was therefore hypothesized that mechanical strain generated by the growing brain induces immature dura mater proliferation and increases osteogenic cytokine expression necessary for growth and healing of the overlying calvaria. Human and rat (n = 40) intracranial volume expansion was calculated as a function of age. These calculations demonstrated that 83 percent of human intracranial volume expansion is complete by 2 years of age and 90 percent of Sprague-Dawley rat intracranial volume expansion is achieved by 2 months of age. Next, the maximal daily circumferential tensile strains that could be generated in immature rat dura mater were calculated, and the corresponding daily biaxial tensile strains in the dura mater during this 2-month period were determined. With the use of a three-parameter monomolecular growth curve, it was calculated that rat dura mater experiences daily equibiaxial strains of at most 9.7 percent and 0.1 percent at birth (day 0) and 60 days of age, respectively. Because it was noted that immature dural cells may experience tensile strains as high as approximately 10 percent, neonatal rat dural cells were subjected to 10 percent equibiaxial strain in vitro, and dural cell proliferation and gene expression profiles were analyzed. When exposed to mechanical strain, immature dural cells rapidly proliferated (5.8-fold increase in proliferating cell nuclear antigen expression at 24 hours). Moreover, mechanical strain induced marked up-regulation of dural cell osteogenic cytokine production; transforming growth factor-beta1 messenger RNA levels increased 3.4-fold at 3 hours and fibroblast growth factor-2 protein levels increased 4.5-fold at 24 hours and 5.6-fold at 48 hours. Finally, mechanical strain increased dural cell expression of markers of osteoblast differentiation (2.8-fold increase in osteopontin levels at 3 hours). These findings suggest that mechanical strain can induce changes in dura mater biological processes and gene expression that may play important roles in coordinating the growth and healing of the neonatal calvaria.

Pneumocephalus Associated with Ethmoidal Sinus Osteoma —Case Report—

A 35-year-old female suffered sudden onset of severe headache upon blowing her nose. No rhinorrhea or signs of meningeal irritation were noted. Computed tomography (CT) with bone windows clearly delineated a bony mass in the right ethmoid sinus, extending into the orbit and intracranially. Conventional CT demonstrated multiple air bubbles in the cisterns and around the mass in the right frontal skull base, suggesting that the mass was associated with entry of the air bubbles into the cranial cavity. T1- and T2-weighted magnetic resonance (MR) imaging showed a low-signal lesion that appeared to be an osteoma but did not show any air bubbles. Through a wide bilateral frontal craniotomy, the cauliflower-like osteoma was found to be protruding intracranially through the skull base and the overlying dura mater. The osteoma was removed, and the dural defect was covered with a fascia graft. Histological examination confirmed that the lesion was an osteoma. The operative procedure resolved the problem of air entry. CT is superior to MR imaging for diagnosing pneumocephalus, by providing a better assessment of bony destruction and better detection of small amounts of intracranial air.

Surgical treatment of the retethered spinal cord after repair of lipomyelomeningocele

In a series of 75 patients with surgically treated lipomyelomeningoceles, the neurological condition of six patients deteriorated 6 months to 14 years after the operation due to repeat tethering of the spinal cord. The tethering resulted from postoperative dense adhesion between the cord and the overlying dura mater. Two of the six patients underwent conventional repeat untethering procedures, and the remaining four were successfully treated with a new surgical technique developed by the authors to prevent such dural adhesion. For this procedure, after complete untethering of the spinal cord, the lumbosacral cord is retained in the center of the dural sac by fine stay sutures between the pia mater of the conus medullaris and the ventral dura mater. In addition, the dura mater is tacked to the posterior arch which is reconstructed with bone grafts at one or two bifid vertebral levels. During a postoperative follow-up period of 1 to 3 years, no further deterioration has been observed and magnetic resonance studies have demonstrated a space filled with cerebrospinal fluid (CSF) around the lumbosacral cord. The authors conclude that long-term observation, both neurological and radiological, is essential even after successful repair of a lipomyelomeningocele. This new surgical procedure can maintain a CSF bath around the lumbosacral cord, thus preventing dural adhesion. Application of this technique will hopefully be beneficial in lipomyelomeningocele patients with a high risk of cord retethering after initial repair.

Origin and Pathological Significance of Smooth Muscle Cells and Myofibroblasts in the Subdural Neomembrane

The outer membranes of the subdural neomembranes (SNs) from 30 patients with chronic subdural hematoma were examined by light and electron microscopes. All the specimens were gained by “en bloc” resection together with the overlying dura mater. Seventeen cases had histories of head injury which varied from 10 to 90 days prior to the operation. Besides the cells known to occur in SN, there were many cells which had ultrastructural characteristics of both smooth muscle cell (SMC) and fibroblast, showing a wide range of transitional morphology between them. They are so-called “myofibroblasts” (MFs) and were observed abundantly in all the cases. In four SNs, typical SMCs were present. They were distributed in a layered fashion in the midzone of the SNs. Examination of the relationship between the incidence of MF and the histological stage of SN or post-traumatic interval revealed that the SMCs were found only in the SNs with fibrosis and after 8 weeks of post-traumatic interval. The SNs containing SMCs showed many MFs in them. It is not recorded in the literature that the presence of MFs in SNs is a common finding, or that SMCs appear in the early stage of SN formation. Although it could not be proven, the origin of SMCs was suggested to be fibroblasts. Considering the recent studies of MF in general pathology, it is conceivable that MFs and SMCs play a role in the contraction and organization of SNs.

Complications of Use of the Neodymium:Yttrium-Aluminum-Garnet Laser in Neurosurgery

Review of the clinical records of 32 patients who underwent operation for brain tumors with the use of the neodymium:yttrium-aluminum-garnet (Nd:YAG) laser during a 4-month period revealed 5 cases of complications related to laser use. One death was presumed to be due to intratumor explosion (the popcorn effect) after excessive Nd:YAG laser application. The other death was due to heat necrosis of the brain stem after radiation of an ependymoma of the 4th ventricle. Two patients suffered neurological deficits. One had facial palsy after radiation of the site of attachment of a meningioma to the petrous bone. The other suffered aphasia and hemiparesis due to heat damage to the cerebral cortex after laser coagulation of the overlying dura mater. The fifth patient suffered postoperative hemorrhage in a residual necrotic chromophobe adenoma after a transsphenoidal approach using the Nd:YAG laser. These complications are preventable. Suggestions are made for the safe use of this laser.

Cryogenic blockade of the visual cortico-thalamic projection in the rat.

A simple procedure is described for rapidly inactivating areas 17 and 18 in the rat by superfusion of the immediately overlying dura mater with chilled, physiological saline solution. Unit recording indicates deep depression of cortical activity within 20 s or less, and equally rapid restoration upon rewarming. Repetition does not appear to be deleterious. During such inactivation of the "visual" cortex (VC) essentially all neurons in the visual portion of the thalamic reticular nucleus (vTRN) are significantly depressed in their background activity and/or in their response to photically or electrically elicited input over the optic tract (Table 1). Activity of neurons in the dorsal portion of the lateral geniculate nucleus (LGNd), on the other hand, is much less likely to be affected, although in occasional neurons the effects should be profound. No evidence of disinhibition was apparent. It is concluded that the vTRN in the rat is highly dependent upon the VC in its activity, and is, thus, likely to be primarily a tool of the VC in the modulation of thalamic events. Extensive work of others shows that the vTRN provides inhibitory input to the LGNd, but in the present experiments the loss of inhibition via this route seems to be balanced by a corresponding loss of general excitatory input when the VC is inactivated.

A CASE OF PRIMARY CANCER OF THE SPHENOID SINUS

Carcinoma of the sphenoid sinus is rare, and even tumors found in the sphenoid sinus are mostly those tumors invading from the epipharynx or the nasal sinuses. Primary carcinoma case of this sinus has not been reported in the literature.In this paper we present a case of primary cancer of the sphenoid sinus. The patient was a 53-year-old male, whose main complaints were headache, amaurosis, exophthalmos and motor disturbance or the left eye without any nasal symptoms. A small polypoid tumor was found in the olfactory fissure on anterior rhinoscopy and not on posterior rhinoscopy.After dissection of the maxilla it was revealed that this tumor has originated and extended from the lateral wall of the sphenoid sinus which was destructed exposing the overlying dura mater. The sinus cavity was filled with papillomatons tumor, but the median wall was covered by thin and flat layer-which was later proved as proliferated squamous cell epithelium, and the rest was covered by the ciliated epithelium.The ethmoid ahd maxillary sinuses seemed intact and infiltration of the tumor was not confirmed histologically in their mucous membrane.The authors believed that this case could be the first case of primary cancer of the sphenoid sinus ever reported in the medical literature.