Dural Layer Research Articles

Holohemispheric Hemorhhage in Infantile Acute Subdural Hematoma: Serial Neuroimaging Analysis

Background: An acute subdural hematoma (ASDH) in infants without any external sign of trauma is differently recognized as shaken baby syndrome (SBS) / abusive head trauma (AHT) in the United States or as infantile acute subdural hematoma (IASDH) due to minor head trauma in Japan. The present case report aimed to demonstrate that IASDH can occur after a mild head impact if the dural border cell layer is disrupted in an infant with cranio-cerebral disproportion (CCD). Case description: A 5-month-old, male patient fell from a baby bed and struck his occiput against a mat. He began to cry and soon thereafter demonstrated signs of altered consciousness. He was taken to a pediatric hospital where computed tomography (CT) revealed a thin subdural hematoma (SDH) surrounding the entire right cerebral hemisphere. Fundoscopy found a right-sided retinal hemorrhage. Magnetic resonance imaging (MRI) on hospital day 4 revealed a thin, high-intensity ASDH surrounding the entire, cerebral convexity on the right side. In addition, benign enlargement of the subarachnoid space (BESS) and large sylvian fissure (LSF) were noted. On hospital day 12 and 18, follow-up MRI revealed a residual SDH with minimal reduction. The patient had an uneventful clinical course and met all the normal, developmental milestones as of his current age of 3 years. Conclusion: The present case is invaluable because it demonstrates that ASDH can occur as a result of a mild, occipital impact. Particularly relevant here is the thin, holohemispheric appearance of the hematoma on neuroimaging studies, which has been suitably termed, holohemispheric subdural hematoma (HHSDH). Also noteworthy is the long-term presence of the HHSDH with minimal reduction of the SDH. The HHSDH may be caused by entrapment of the hematoma in the dural border cell layer in the absence of any communication with the surrounding structures.

How I do it: Endoscopic endonasal resection of the medial wall of the cavernous sinus.

Resection of the medial wall of the cavernous sinus (MWCSR) is a growing surgical maneuver for the radical removal of pituitary adenomas. We present a simple modification of the technique following the two dural layers of the floor of the sella turcica, allowing for early identification of the medial wall and simplifying dissection. We support this technique with an anatomical analysis on cadaveric specimens and clarifying dissection images. Recognition and dissection of the dural unfolding of the floor of the sella turcica are "key points" that lower the risk and facilitate the MWCSR.

Pathogenesis and epidemiology of chronic subdural hematoma

Background: Chronic subdural hematoma (SDH) is a common condition encountered in neurosurgical practice; however, its pathogenesis remains controversial.Current Concepts: SDH refers to blood accumulation inside the dura and is classified into acute, subacute, and chronic types. Histopathologically, acute SDH shows no neomembrane formation and the hematoma is a clot, in contrast to chronic SDH characterized by a neomembrane surrounding the liquefied hematoma. SDH is usually categorized into acute and chronic types, with subacute SDH being more similar to chronic SDH. Posttraumatic subdural lesions include acute and chronic SDH, subdural hygroma (SDG), or effusion. SDG is a blood-tinged fluid accompanied by neomembrane formation in some cases. These lesions are pathologically different from each other but may change depending on the situation.Discussion and Conclusion: Chronic SDH mainly originates from an SDG and acute SDH. SDG is usually triggered by trauma but only occurs in patients in whom sufficient potential space is available and may occur spontaneously in such cases. Therefore, SDG frequently occurs in children and in elderly patients, in men with a larger skull size, and on the left side of the body, which usually shows a wider hemisphere. Separation of the dural border cell layer causes inflammation, indicated by fibroblast proliferation and neovascularization. Conversion of an SDG into a chronic SDH or enlargement of a chronic SDH is attributable to formation of neomembranes, neovascularization, and repeated microhemorrhages from fragile capillaries. Chronic SDH is treated with removal of the hematoma to relieve the mass effect and embolization of the feeding artery for the bleeder. Outcomes of chronic SDH depend on the absorptive-expansion capacity dynamics.

Dural mural cells paint an anti-inflammatory picture.

Mural cells directly contact macrophages in the dural layer of the meninges to suppress pro-inflammatory phenotypes, including antigen presentation and lymphocyte differentiation. These mechanisms represent new targets for modulating CNS immune surveillance and pathological inflammation (Min et al. 2024. J. Exp. Med.https://doi.org/10.1084/jem.20230326).

A rare entity of primary hydatid cyst located between the two laiers of the intracranial dura in a child: a case report

Background: Hydatid disease is a parasitic infection caused by the tapeworm Echinococcus granulosus. Intracranial hydatid cysts are rare and account for less than 3% of all cases of hydatid disease. Typically, these cysts are found in the intracerebral spaces. However, this study presents an extremely rare intradural hydatid cyst. Case Presentation: This study presents the case of an 8-year-old boy presented with a 3-month history of headache and vomiting without any neurological deficit. Full radiological investigations were performed, and only brain magnetic resonance imaging showed a large cerebral hydatid cyst located within the dura layers between the periosteal and the endosteal layers. Surgery was performed without cyst rupture, confirming the intracerebral intradural location. Conclusion: Early diagnosis and treatment for intracranial hydatid cysts are crucial to prevent complications such as neurological deficits, seizures, and even death. In this case, the intracerebral intradural location of the cyst is extremely rare.

A rare entity of primary hydatid cyst located between the two laiers of the intracranial dura in a child: a case report

Background: Hydatid disease is a parasitic infection caused by the tapeworm Echinococcus granulosus. Intracranial hydatid cysts are rare and account for less than 3% of all cases of hydatid disease. Typically, these cysts are found in the intracerebral spaces. However, this study presents an extremely rare intradural hydatid cyst. Case Presentation: This study presents the case of an 8-year-old boy presented with a 3-month history of headache and vomiting without any neurological deficit. Full radiological investigations were performed, and only brain magnetic resonance imaging showed a large cerebral hydatid cyst located within the dura layers between the periosteal and the endosteal layers. Surgery was performed without cyst rupture, confirming the intracerebral intradural location. Conclusion: Early diagnosis and treatment for intracranial hydatid cysts are crucial to prevent complications such as neurological deficits, seizures, and even death. In this case, the intracerebral intradural location of the cyst is extremely rare.

Predictive factors for cranioplasty complications – A decade's experience

IntroductionCranioplasty (CP) following craniectomy provides cerebral protection, improves cerebrospinal fluid dynamics, and restores cosmesis. Although often viewed as minor, CP can have major complications. Research questionThis study aims to identify the predictive factors for post-operative complications in patients undergoing CP after decompressive craniectomy. MethodsWe conducted a retrospective study at a tertiary hospital, analyzing patients who underwent CP after decompressive craniectomy (DC) from 2008 to 2019. Patient demographics, medical history, and surgery details were retrieved from hospital records. Complications included symptomatic intracerebral haemorrhage, extradural or subdural haemorrhage, hydrocephalus, infection, or bone resorption. ResultsThe study included 168 patients: 139 adults (mean age 47.6 ± 12.68 years) and 29 pediatric patients (mean age 11.8 ± 5.62 years), with a slight male predominance. The overall complication rate was 26.2%, with infection being the most common (8.9%). Predictive factors for CP complications identified by binomial logistic regression, controlling for age and sex, included primary coagulopathy (14.3-fold risk increase, p = 0.034), intraoperative ventricular puncture (7.9-fold risk increase, p = 0.009), and intraoperative dural layer breach (2.8-fold risk increase, p = 0.033). Pre-CP home living was a protective factor. ConclusionsCP requires vigilant management to prevent complications. Primary coagulopathy, intraoperative ventricular puncture, and dural layer breach are significant risk factors for complications.

Anterior Petrosectomy With Intertentorial Approach.

The extradural anterior petrosal approach (EAPA) can present a challenge because it deals with critical structures in a narrow, confined corridor. It is associated with several potential approach-related risks including temporal lobe and venous injuries. Tentorial peeling has the potential to largely eliminate these risks during the approach and may offer more options for tailoring the dural opening to the anatomic region that one wants to expose. Anatomic dissections of five adult injected non-formalin-fixed cadaveric heads were performed. Anterior petrosectomy with intertentorial approach (APIA) through a tentorial peeling was completed. Step-by-step documentation of the cadaveric dissections and diagrammatic representations are presented along with an illustrative case. Tentorial peeling separates the tentorium into a temporal tentorial leaf and posterior fossa tentorial leaf, adding a fourth dural layer to the three classic ones described during a standard EAPA. This opens out the intertentorial space and offers more options for tailoring the dural incisions specific to the pathology being treated. This represents a unique possibility to address brainstem or skull base pathology along the mid- and upper clivus with the ability to keep the entire temporal lobe and basal temporal veins covered by the temporal tentorial leaf. The APIA was successfully used for the resection of a large clival chordoma in the illustrative case. APIA is an interesting modification to the classic EAPA to reduce the approach-related morbidity. The risk reduction achieved is by eliminating the exposure of the temporal lobe while maintaining the excellent access to the petroclival region. It also provides several options to tailor the durotomies based on the localization of the lesion.

Accuracy of Bleeding Volume as a Predictor of Mortality in Epidural Hemorrhage Patients Undergoing Surgery at Dr. Mohammad Hoesin General Hospital, Palembang, Indonesia

Introduction: EDH is a collection of blood clots between the dura layer and the cranium. This is usually caused by rupture of the middle meningeal artery but can also be caused by rupture of the dural venous sinus, diploic vein, meningeal vein, or bleeding from the fracture line. CT scan is the investigation of choice to detect intracranial injury after trauma. CT scans can also identify additional features that influence the results, namely, midline shifting, blood clot thickness and hematoma volume, cerebral edema, and cranium fractures. This study aimed to determine the accuracy of bleeding volume as a predictor of mortality in epidural hemorrhage patients undergoing surgery at Dr. Mohammad Hoesin General Hospital, Palembang Indonesia.
 Methods: This study is a retrospective study of prognostic tests to determine the accuracy of bleeding volume as a predictor of mortality in patients with EDH who underwent surgery at Dr. Mohammad Hoesin General Hospital. This study uses secondary data obtained from medical record data at the medical records installation of Dr. Mohammad Hoesin General Hospital, Palembang, Indonesia. A total of 106 research subjects participated in this study. 
 Results: The sensitivity value of bleeding volume was 77.7%, and specificity was 78.3%, and also obtained a positive predictive value of 7.21% and a negative predictive value of 97.4%, it can be concluded that bleeding volume is not accurate as a predictor of mortality.
 Conclusion: Bleeding volume is not an accurate predictor of mortality in epidural hemorrhage patients undergoing surgery at Dr. Mohammad Hoesin General Hospital, Palembang Indonesia.

Molecular anatomy of adult mouse leptomeninges

Leptomeninges, consisting of the pia mater and arachnoid, form a connective tissue investment and barrier enclosure of the brain. The exact nature of leptomeningeal cells has long been debated. In this study, we identify five molecularly distinct fibroblast-like transcriptomes in cerebral leptomeninges; link them to anatomically distinct cell types of the pia, inner arachnoid, outer arachnoid barrier, and dural border layer; and contrast them to a sixth fibroblast-like transcriptome present in the choroid plexus and median eminence. Newly identified transcriptional markers enabled molecular characterization of cell types responsible for adherence of arachnoid layers to one another and for the arachnoid barrier. These markers also proved useful in identifying the molecular features of leptomeningeal development, injury, and repair that were preserved or changed after traumatic brain injury. Together, the findings highlight the value of identifying fibroblast transcriptional subsets and their cellular locations toward advancing the understanding of leptomeningeal physiology and pathology.

Natural killer cells and innate lymphoid cells 1 tune anxiety-like behavior and memory in mice via interferon-γ and acetylcholine

The mechanisms of communication between the brain and the immune cells are still largely unclear. Here, we characterize the populations of resident natural killer (NK) cells and innate lymphoid cells (ILC) 1 in the meningeal dura layer of adult mice. We describe that ILC1/NK cell-derived interferon-γ and acetylcholine can contribute to the modulation of brain homeostatic functions, shaping synaptic neuronal transmission and neurotransmitter levels with effects on mice behavior. In detail, the interferon-γ plays a role in the formation of non-spatial memory, tuning the frequency of GABAergic neurotransmission on cortical pyramidal neurons, while the acetylcholine is a mediator involved in the modulation of brain circuitries that regulate anxiety-like behavior. These findings disclose mechanisms of immune-to-brain communication that modulate brain functions under physiological conditions.

Anatomy and Histology of the Petrous Carotid Membrane: Application to Skull Base Surgery

Published reports regarding the tissue types that surround the internal carotid artery (ICA) as it travels through the carotid canal vary. Reports have variably defined this membrane as periosteum, loose areolar tissue, or dura mater. With such discrepancies and realizing that knowledge of this tissue might be important for skull base surgeons who expose or mobilize the ICA at this location, the present anatomical/histological study was performed. In 8 adult cadavers (16 sides), the contents of the carotid canal were evaluated; specifically, the membrane surrounding the petrous part of the ICA was studied, and its relationship to the deeper lying artery was observed. These specimens were stored in formalin and submitted for histological evaluation. Grossly, the membrane within the carotid canal traversed the entire carotid canal and was loosely adherent to the underlying petrous part of the ICA. Histologically, all membranes surrounding the petrous part of the ICA were consistent with dura mater. The dura mater of the carotid canal had an outer endosteal layer and an inner meningeal layer as well as a clear dural border cell layer in most specimens that approximated and was loosely applied to the adventitial layer of the petrous part of the ICA. The membrane that surrounds the petrous part of the ICA is dura mater. To our knowledge, this is the first histological investigation of this structure and thus serves to establish the true identity of this membrane and correct previous reports in the literature that have erroneously concluded that it is periosteum or loose areolar tissue.

Keyhole retrosigmoid approach without watertight dural closure - Evaluation of a minimalistic approach.

The retrosigmoid craniotomy is a versatile surgical approach to the cerebellopontine angle though cerebrospinal fluid leak remains a concern, with a reported prevalence of 0-22 %. A host of closure materials and strategies have been proposed to achieve a watertight dural closure to varying degrees of success. We review our series of keyhole retrosigmoid craniotomies and describe our simple, standardized method of closure without watertight dural closure. A retrospective review of all retrosigmoid craniotomies performed by the senior author was completed. Closure was achieved by placing an oversized piece of gelatin in the subdural space. The dura is grossly approximated. An oversized sheet of collagen matrix is placed as an overlay followed by gelatin sponge in the craniectomy defect held in place with titanium mesh. The superficial layers are approximated. The skin is closed with a running sub-cuticular suture followed by skin glue. Patient demographics, cerebrospinal fluid leak risk factors, and surgical outcomes were determined. A total of 114 patients were included. There was one case (0.9 %) of CSF leak, which resolved with placement of a lumbar drain for 5 days. The patient had one defined risk factor (morbid obesity, BMI 41.0kg/m2). Obtaining a watertight dural layer closure has been the generally accepted strategy in preventing CSF leaks in a traditional retrosigmoid approach. In keyhole retrosigmoid approaches it may not be necessary by utilizing a simple gelfoam bolstered collagen matrix onlay technique potentially improving outcome measures including operative time.

The Oculomotor Cistern and Its Role in the Management of Pituitary Lesions: An Anatomical, Radiographic, and Clinical Scoping Review.

The oculomotor cistern (OMC) is a cerebrospinal fluid space bound by meningeal layers that surrounds the oculomotor nerve as it crosses the oculomotor triangle to reach the lateral wall of the cavernous sinus at the level of the anterior clinoid process. Although several anatomical and radiological studies are available, its anatomy and relationship with pituitary adenomas (PAs) are still matter of discussion. The aim of the study is to provide an updated and focused overview of the OMC, highlighting the different perspectives and descriptions from anatomical, radiological, and clinical points of view. A scoping review was conducted up to 29th October 2022, according to PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) criteria. PubMed, Web of Science, Scopus databases, and correlated citations were investigated. Of the 562 records identified, 22 were included in the present analysis. There were 13, 5, and 4 anatomo-surgical, radiological, and clinical studies, respectively. Though there is general consensus on its definition, data are variable on different features of OMC. Defects or absence of dural layers adjacent to the oculomotor nerve were described in only 4 papers. The transition from meningeal to neural layers is still unclear. PAs with OMC involvement are poorly studied and have unique clinical characteristics. To date, 21 patients have been described; the reported prevalence of OMC involvement by PAs ranges from 4.1% to 14.6%. Clarifying the OMC features with further systematic studies may not only broaden theoretical knowledge but also have implications on endoscopic transnasal pituitary surgery.

Middle Meningeal Artery Embolization in the Management of Chronic Subdural Hematoma: a Comprehensive Review of Current Literature

Chronic subdural hematoma (cSDH) is a common intracranial hemorrhagic disorder with a high incidence rate among the elderly. While small, asymptomatic cSDH may resolve spontaneously, surgical intervention has been the treatment of choice for larger, symptomatic cases. Surgical evacuation of cSDH may be associated with high rates of recurrence, and even asymptomatic cSDH cases tend to progress. Over the last few years, middle meningeal artery (MMA) embolization has proven to be a safe non-invasive treatment of choice with favorable outcomes and a low recurrence rate. The ensuing paper discusses current treatment modalities for cSDH and reviews existing literature on the anatomy of MMA and its embolization as a treatment option for cSDH. Recent studies show that traumatic head injury leading to subdural hemorrhage can induce neovascularization that may initiate a cycle of recurrent subdural hematoma. Distal branches of MMA supply blood to the dural layers. Several studies have revealed that embolization of the MMA can stop the neovascularization process and blood flow. In addition, patients who underwent MMA embolization had a significantly quicker brain re-expansion and lower recurrence rate. Although the management of cSDH is still very much a dilemma, recent research findings bring MMA embolization to light as a promising treatment alternative and adjunctive therapy.

Surgical management of idiopathic thoracal ventral spinal cord herniation: a case report

IntroductionIdiopathic spinal cord herniation is a rare entity that is characterized by the displacement of the spinal cord through a defect in the dural layer and presents with symptoms of myelopathy. Surgical management usually results in good outcomes.Case presentationA 58-year-old female patient presented with weakness of both legs since four months. Her neurological examination showed paraplegia in the lower extremities, and ventral herniation was detected in the T9 vertebral level. The patient underwent surgery. Left T9 hemilaminectomy was followed by the reduction in the herniated spinal cord into its physiological location and the covering the anteriorly located dural defect via circumferentially covering the dural surface of the corresponding vertebral level. Postoperatively, the patient’s neurological status improved gradually and radiological scans showed a total reduction in the herniation.ConclusionDespite the rarity of the pathology, spinal cord herniation should be included in the differential diagnosis of the patients presenting with myelopathy or Brown–Séquard syndrome.

Spontaneous epidural and subdural hematomas of the spine: Review of anatomy and imaging findings.

Spontaneous epidural (SEH) and subdural hematomas (SSH) of the spine are a rare cause of spinal injury and morbidity. They often present in the emergency setting, though magnetic resonance imaging is the gold-standard for diagnosis. Knowledge of anatomy, and in particular of the dural layers of the spine, is crucial to understand the location of SEH and SSH and their relationship with spinal structure. In this pictorial review, we aim to explain imaging features of the SEH and SSH, and to rule out their main differential diagnosis.

Seno cavernoso: anatomía, histología y terminología.

Although the cavernous sinus (CS) has been studied since 1695, its anatomy and name are still under discussion. Anatomy and histology of 40 CS from human cadavers were studied, included both from a newborn specimen. Two walls limit the CS, an inferior medial one composed only of the dura's outer layer and a superior lateral one consisting of both dura's layers. Sinusoidal veins pass through the lateral wall of the CS as a transition between venous tributaries and the CS. An endothelial layer covers the inner surface of the CS and the outer surface of the internal carotid artery. The space within the CS shows trabeculae, which are rarer in adults compared to the newborn. The loss of trabeculae in the CS may be a natural process along with life. In conclusion, the CS is a real sinus, and the term "cavernous sinus" is appropriately applied.

Role of surgery in management of intracranial dural arteriovenous fistulas.

Intracranial dural arteriovenous fistulas (DAVF) are abnormal connections between intracranial arterial and venous systems within the dural layers. Intracranial DAVFs are rare but can occur wherever dural components exist. The pathogenesis of DAVFs is controversial. Venous hypertension is considered as a main cause of clinical symptoms which are subclassified into asymptomatic, benign and aggressive manifestations. To date, several classification schemes have been proposed to stratify the natural course and risks of DAVFs. Currently, endovascular therapy is the main treatment modality. Moreover, the use of radiosurgery and radiotherapy has been limited. Open surgery is also selectively performed as a main treatment modality for specific types of DAVFs and an adjunctive modality for the endovascular approach. Herein, we present a review of the general perspectives of intracranial DAVFs with an emphasis on the role of surgery.

Spinal extradural arachnoid cysts: A novel formation mechanism and dural defect location technology

PurposeThe formation mechanism of spinal extradural arachnoid cysts (SEACs) remains unclear. There are several hypotheses for the formation of SEACs, but none of them can fully explain its pathological findings and surgical procedures. In this study, we retrospectively analyzed the cases of SEACs, aiming to clarify the formation mechanism of SEACs. In addition, we summarize a concise method for locating dural defects preoperatively and formulate a putative explanation of this method. MethodsThe clinical data of 14 patients with SEACs underwent surgery in our hospital from January 2017 to December 2021 were retrospectively analyzed. ResultsFourteen patients were identified during the study period. The cysts all spanned the T12/L1 segment, and dural defects were also located at the T12/L1 level (2 cases not recorded) as well as the middle or the upper-middle level of the cysts. Nine cases were treated with total cyst excision, 2 cases were treated with dural defect closure only, and 3 cases were treated with total cyst excision and dural defect closure. Histopathological examination demonstrated that the cyst wall contained both the arachnoid epithelial and compact fibrous connective tissue. The symptoms were relieved in all patients, and no recurrence was observed. ConclusionsAccording to intraoperative and pathological findings, the dural outer layer cyst (DOLC) is a more reasonable hypothesis about SEACs formation. When CT myelography or cinematic MRI cannot determine the location of the dural defect preoperatively, it can be located according to the middle level of the SEACs with high accuracy.