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The central nervous system is lined by meninges, classically known as dura, arachnoid, and pia mater. We show the existence of a fourth meningeal layer that compartmentalizes the subarachnoid space in the mouse and human brain, designated the subarachnoid lymphatic-like membrane (SLYM). SLYM is morpho- and immunophenotypically similar to the mesothelial membrane lining of peripheral organs and body cavities, and it encases blood vessels and harbors immune cells. Functionally, the close apposition of SLYM with the endothelial lining of the meningeal venous sinus permits direct exchange of small solutes between cerebrospinal fluid and venous blood, thus representing the mouse equivalent of the arachnoid granulations. The functional characterization of SLYM provides fundamental insights into brain immune barriers and fluid transport.

Background RNA extraction is a step that precedes several molecular techniques. The fibrous tissue, more specifically the dura mater, has several limitations in routine protocols, and lacks optimization protocols to overcome these problems. Objective To test stock reagents and purification kits, optimizing commercial kit protocols for RNA extraction from the dura mater. Methods Dura mater samples were obtained from eight Wistar rats and maintained in two different stabilizers. The samples were purified using four different protocols, and the RNA was evaluated for the yield and purity in NanoDrop 2000 (Thermo Scientific, Wilmington, DE, United States). Beta-actin gene was used for analyzing gene expression, since is one of the most used reference genes. Results The RNA preservation was similar in both stabilizers. The addition of an incubation step prior the purification protocols allowed better tissue digestion and RNA recovery. The RNA purified using the protocols membrane-based showed higher quality than liquid-liquid purification. This impact was observed in the 3-week evaluation using RT-qPCR. Conclusion Stabilizers are efficient for RNA preservation and membrane-based purification protocols are more suitable for RNA recovery from dura mater tissue, allowing the evaluation of gene expression in this type of tissue. Adaptations in the dura mater RNA extraction protocol differ from the pre-established protocols because it takes into account the peculiarity of fibrous tissue and low cellularity. In addition to providing a low-cost mechanism, based on techniques that are part of the laboratory routine, it is possible to improve the quality of the extracted material, ensuring greater efficiency in the use of subsequent techniques. Resumo Antecedentes A extração de RNA é uma etapa que antecede várias técnicas moleculares. O tecido fibroso, mais especificamente a dura-máter, apresenta várias limitações nos protocolos de rotina e carece de protocolos de otimização para superar estes problemas. Objetivo Testar reagentes de estoque e kits de purificação, otimizando protocolos de kits comerciais para extração de RNA da dura-máter. Métodos Amostras de dura-máter foram obtidas de oito ratos Wistar e mantidas em dois estabilizadores diferentes. As amostras foram purificadas em quatro protocolos diferentes e o RNA foi avaliado quanto ao rendimento e pureza no NanoDrop 2000 (Thermo Scientific, Wilmington, DE, United States). O gene da beta-actina foi utilizado para analisar a expressão gênica, uma vez que é um dos genes de referência mais utilizados. Resultados A preservação do RNA foi semelhante em ambos os estabilizadores. A adição de uma etapa de incubação antes dos protocolos de purificação permitiu uma melhor digestão do tecido e recuperação de RNA. O RNA purificado pelos protocolos baseados em membrana apresentou qualidade superior ao da purificação líquido-líquido. Este impacto foi observado na avaliação de três semanas usando RT-qPCR. Conclusão Os estabilizadores são eficientes para preservação do RNA e os protocolos de purificação baseados em membrana são mais adequados para recuperação de RNA do tecido da dura-máter, permitindo a avaliação da expressão gênica neste tipo de tecido. As adaptações no protocolo de extração de RNA da dura-máter diferem dos protocolos preestabelecidos porque leva em consideração a peculiaridade do tecido fibroso e com baixa celularidade. Além de fornecer um mecanismo de baixo custo, baseado em técnicas que fazem parte da rotina laboratorial, é possível melhorar a qualidade do material extraído, garantindo maior eficácia no uso de técnicas subsequentes.

Falcine meningioma is usually approached ipsilaterally, and the technique for tumor removal has traditionally been performed under microscopy. We report a surgical procedure for large falcine meningioma by an endoscopic contralateral interhemispheric transfalcine keyhole approach.The study period was from September 2019 to March 2021. Study participants were patients with World Health Organization grade I meningioma showing falx attachment, excluding neurofibromatosis, who underwent initial surgery at our institution. The surgical procedure begins with a small contralateral craniotomy of about 3 cm, followed by insertion of an endoscope. The tumor attachment to the falx is excised, exposing the tumor. Internal decompression is performed, and the lesion is dissected from the surrounding brain before removal through the falx.An endoscopic contralateral interhemispheric transfalcine keyhole approach was used to resect 4 cases of large falcine meningioma. The mean operation time was 265 minutes (range: 216-294 minutes), achieving Simpson grade I removal in all cases. No evidence of cerebral infarction, cerebral edema, or new neurological complaints related to impaired venous return was seen using this surgical method.In the case of falcine meningioma, the endoscopic keyhole contralateral technique allows detachment of the tumor from the falx and safe manipulation in a minor field of view. In addition, because the craniotomy is smaller and the operation time is shorter, this procedure offers a less-invasive approach for the patient. This technique is thus, in our opinion, quite advantageous.

(1) Background: The inferior anastomotic vein of Labbé (LV) courses on the temporal lobe, from the sylvian fissure towards the tentorium cerebelli and finishes at the transverse sinus (TS). The importance of the LV topography is related to skull base neurosurgical approaches. Based on the hypothesis of the existence of as yet unidentified anatomical possibilities of the LV, we aimed through this research to document the superficial venous topographic patterns at the lateral and inferior surfaces of the temporal lobe. (2) Methods: A retrospective cohort of 50 computed tomography angiograms (CTAs) of 32 males and 18 females was documented. (3) Results: Absent (type 0) LVs were found in 6% of cases. Anterior (temporal, squamosal–petrosal–mastoid, type 1) LVs were found in 12% of cases. LVs with a posterior, temporoparietal course (type 2) were found to be bilateral in 46% of cases and unilateral in 36% of cases. Type 3 LVs (posterior, parietooccipital) were found to be bilateral in 8% and unilateral in 32% of cases. In 24% of cases, duplicate LVs were found that were either complete or incomplete. A quadruplicate LV was found in a male case. On 78 sides, the LV drained either into a tentorial sinus or into the TS. (4) Conclusions: The anatomy of the vein of Labbé is variable in terms of its course, the number of veins and the modality of drainage; thus, it should determine personalized neurosurgical and interventional approaches. A new classification of the anatomical variations of Labbé’s vein, as detected on the CTAs, is proposed here (types 0–3).

The endothelial-lined dural venous sinuses collect blood from the brain, meninges, and calvaria and drain it to the internal jugular veins. The adult drainage pathway of the venous sinuses confluent is commonly via the transverse and sigmoid sinuses to the jugular bulb. The occipital (OS) and marginal (MS) sinuses are well-represented before birth, in most cases. During a retrospective study of the computed tomography angiograms of a 64 y.o. female was found a rare combination of variants of the posterior fossa sinuses. The confluence of the dural venous sinuses was rhomboidal and drained superiorly the superior sagittal sinus, and inferiorly a well-represented occipital sinus (OS). The transverse sinuses were aplastic, on the right side, and hypoplastic on the opposite side. The OS further drained into the MS which, on each side, emptied into the respective jugular bulb. On each side a condylar vein left the junction of the sigmoid sinus and jugular bulb. Such posterior fossa drainage, exclusively on the OS-MS pathway, should be kept in mind when transections of the venous sinuses are intended during neurosurgical approaches of the foramen magnum. The OS-MS drainage is rather a persisting fetal pattern. The bilateral anatomical exclusion of the transverse sinuses is an added condition to spare the OS and MS.

Incidental durotomies resulting in symptomatic postoperative cerebrospinal fluid (CSF) leaks can be treated with bedrest, subarachnoid lumbar drain, and surgical re-exploration. Another option is an epidural blood patch, which forms a clot over the dural tear in a minimally invasive manner. Our objective was to describe our center's outcomes and complications following epidural blood patches for symptomatic postoperative durotomies.Patients undergoing spine surgeries at one institution from 2012-2020 were included. Patient charts were reviewed for demographic information, surgical data, rate of dural tear, type of repair, and use of blood patches postoperatively.A total of 1392 patients (726 male, 666 female, average age: 56.3 ± 15.4 years), including 436 cervical and 956 posterior thoracolumbar/lumbar spine surgeries were screened. There were 6 (1.4%) cervical, 64 (6.7%) lumbar, and a total of 70 (5.0%) patients with incidental dural tears/blebs. Of these patients, we identified 2 cervical and 8 lumbar spine patients with persistent CSF leaks who received epidural blood patches postoperatively. Nine of 10 (90%) had resolution of symptoms. One lumbar patient failed both an initial blood patch and subsequent surgical re-exploration, but had successful relief after a second blood patch.The incidence of dural tears/blebs was 1.4% in cervical, 6.7% in lumbar, and 5.0% in all spine surgeries. Of the 10 patients with symptomatic CSF leaks, 9 were successfully treated with blood patches. Targeted epidural blood patch is effective in treating symptomatic CSF leaks and minimizes the morbidity of surgical re-exploration.

The myodural bridge (MDB) complex are fibrous bridges that functionally connect the spinal dura mater to the suboccipital musculature. Previously, we described the maturational sequence of the MDB within the posterior atlanto-occipital interspace of the rat. The present paper describes the morphology and developmental maturation of the MDB within the posterior atlanto-axial interspace of the rat. In the present study, E18 embryonic rats, newborn rats, and adult rats were selected to evaluate the development and growth of the MDB. Within the posterior atlanto-axial interspace of the rat, the fibers of the MDB and its associated muscles, in the embryonic rat, were observed to be scarce and lightly stained. In contrast, these same structures observed in the postnatal rat were quite apparent and robustly stained. After birth, it was observed that MDB originated from the rectus capitis dorsal major muscle, extended forward and downward, and finally merged with the posterior atlanto-axial membrane. As the rats developed and matured, the observed MDB fibers passing through the posterior atlanto-axial interspace appeared denser and more organized. This study evidenced that the MDB fibers within the posterior atlanto-axial interspace were primarily composed of type I collagen fibers in the postnatal rat. By observing the suboccipital region, we are able to hypothesize that the MDB complex plays a key role in maintaining the subdural space located within the upper cervical segment during growth and development. This study provides a morphological basis for future research on the function of the MDB complex.

Patient-derived cells hold great promise for precision medicine approaches in human health. Human dermal fibroblasts have been a major source of cells for reprogramming and differentiating into specific cell types for disease modeling. Postmortem human dura mater has been suggested as a primary source of fibroblasts for in vitro modeling of neurodegenerative diseases. Although fibroblast-like cells from human and mouse dura mater have been previously described, their utility for reprogramming and direct differentiation protocols has not been fully established. In this study, cells derived from postmortem dura mater are directly compared to those from dermal biopsies of living subjects. In two instances, we have isolated and compared dermal and dural cell lines from the same subject. Notably, striking differences were observed between cells of dermal and dural origin. Compared to dermal fibroblasts, postmortem dura mater-derived cells demonstrated different morphology, slower growth rates, and a higher rate of karyotype abnormality. Dura mater-derived cells also failed to express fibroblast protein markers. When dermal fibroblasts and dura mater-derived cells from the same subject were compared, they exhibited highly divergent gene expression profiles that suggest dura mater cells originated from a mixed mural lineage. Given their postmortem origin, somatic mutation signatures of dura mater-derived cells were assessed and suggest defective DNA damage repair. This study argues for rigorous karyotyping of postmortem derived cell lines and highlights limitations of postmortem human dura mater-derived cells for modeling normal biology or disease-associated pathobiology. Graphical abstract

We herein report a 73-year-old man with isolated hypertrophic pachymeningitis (HP) showing serological and pathological characteristics of both IgG4-related disorders and granulomatosis with polyangiitis. The patient presented with chronic onset headaches and ophthalmalgia. Brain magnetic resonance imaging (MRI) revealed a hypertrophic enhanced dura mater. Serum IgG4 and myeloperoxidase anti-neutrophil cytoplasmic antibody (MPO-ANCA) levels were elevated. A dura mater biopsy showed infiltration of numerous IgG4-positive plasma cells and granulomatous inflammation without apparent vasculitic lesions, storiform fibrosis, or obstructive phlebitis. Corticosteroid treatments improved his clinical symptoms and MRI findings. There have been reports of MPO-ANCA-positive IgG4-related HP presenting as granulomatous inflammation in the dura mater.

Dural suturing is one of the most robust reconstruction methods in transsphenoidal surgery; however, the technique is considered difficult, primarily due to the restricted range of needle movement.We performed dural threading during transsphenoidal surgery by holding the needle with forceps as a hook and moving the needle in a distal to proximal direction.Our dural suturing technique is simple and quick. It can be used not only for dural closure but also for other procedures, such as controlling haemostasis from the intercavernous sinus and dural tenting.

To perform measurements in normal brain imaging studies from the free edge of the falx cerebri to the genu and the body of the corpus callosum and perform a statistical analysis based on age, type of study, and sex highlighting potential surgical implication of these measurements.In 193 normal brain imaging studies, 3 anatomical points of the corpus callosum were used to measure the distance to the falx cerebri. Horos and RadiAnt DICOM Viewer software were used to perform the measurements. Statistical analysis of data was performed with Minitab18 software.The results obtained in computed tomography (CT) studies were: distance A, mean 2.1065 cm; distance B, mean 2.2677 cm; distance C, mean 1.765 cm. The results obtained in magnetic resonance imaging studies were: distance A, mean 1.7148 cm; distance B, mean 2.1197 cm; distance C, mean 1.5321 cm. Statistically significant differences were obtained in measurements related to the type of study and in measurements made in CT studies related to age.There is a distance from the free edge of the falx cerebri to the genu and body of the corpus callosum of at least 1 cm in both CT and magnetic resonance imaging studies of normal brains. Statistically significant differences were found in the measurements in relation to the type of study and in relation to age in the measurements made in CT studies. These measurements could be important in determining the extent of bone resection in certain types of decompressive craniectomies.

Patients treated for complex oncological calvarial defects are at a higher risk of severe complications (38%): infection, meningitis, dehiscence, and hardware/brain exposure. The patient cohorts at our center have led to the development of the "U-Turn" technical (UTT) addition of our previously reported turnover "tournedos" myocutaneous latissimus dorsi free flap. This allows for an improved ability to fill these large, round, complex defects, maintaining the safety of our original surgical technique, while improving aesthetic outcomes.A single-institution case series of complex microsurgical reconstructions for full-thickness oncologic calvarial defects using the UTT addition was reviewed. A free 30 cm latissimus dorsi myocutaneous flap was harvested, deepithelialized in-situ, and turned over with the dermal component laying on the avascular reconstructed dura. Both ends were positioned next to each other into a U shape and sutured together, creating a 15 cm round paddle.Fifty two complex microsurgical procedures for oncological calvarial defect reconstruction were performed. The 7 most recent were ideal for the UTT addition. There were no instances of microvascular thrombosis, infection, cerebral spinal fluid leak, or major wound healing problems. All procedures provided stable volume and full coverage, with all patients requiring debulking and contouring to achieve optimal aesthetic results. All flaps remained stable after debulking.The UTT addition takes the previously established "tournedos" latissimus dorsi free flap to another level of reconstruction, providing a larger volumetric filler, round shape, better defect filling, better durability, and better aesthetics, even in irradiated and/or infected calvarial chronic wound bed.

Extended endonasal transsphenoidal surgery (eTSS) offers a wide surgical field for various parasellar lesions; however, intraoperative high-flow cerebrospinal fluid (CSF) leakage is inevitable. Therefore, secure sellar reconstruction methods are essential to prevent postoperative CSF leakage. Although collagen matrix has been applied for dural reconstruction in neurosurgery, its suitability for application in extended eTSS remains unclear.Fifteen patients underwent modified shoelace dural closure using collagen matrix after lesionectomy via extended eTSS. In this technique, a collagen matrix, which was placed subdurally (inlay graft), was continuously sutured with both open dural edges like a shoelace. Then, another collagen matrix was placed epidurally (onlay graft), and rigid reconstruction was performed using the septal bone and a resorbable fixation mesh. Postoperative CSF leakage did not occur in fourteen patients, but did in one patient with tuberculum sellae meningioma. In this case, the CSF leakage point was detected just around the area between the coagulated dura and the adjacent collagen matrix. The collagen matrix harvested from this area was pathologically examined; neovascularization and fibroblastic infiltration into the collagen matrix were not detected. On the other hand, neovascularization and fibroblast infiltration into the collagen matrix were apparent on the surface of the collagen matrix harvested from the non-CSF leakage area.Our novel dural closure technique using collagen matrix could be an effective option for sellar reconstruction in extended eTSS; however, it should be applied in patients in whom normal dural edges are preserved.Clinical trial registrationNot applicable

Spinal meningiomas are the common benign tumors in intradural extramedullary spinal tumors. Simpson grade I resection is recommended to avoid tumor recurrence. However, the dura reconstruction increases a risk of cerebrospinal fluid leakage after this surgical resection. To address this concern, the inner dura layer resection and long-term surgical outcomes of this technique were designed and examined after total tumor resection to preserve the outer dura layer.This study included 40 spinal meningioma patients undergoing the outer dura layer resection between 2002 and 2019. Clinical characteristics, radiologic features, preoperative and postoperative functional states, tumor recurrence, and perioperative complications were described and evaluated.A total of 40 spinal meningioma cases with the median age of 63 years (36-81 years) were enrolled in this study. The median postoperative follow-up period of all 40 cases was 96 months (34-193 months). About 82.5% of cases were located in the thoracic spine, while 16.5% of cases were located in the cervical spine. Of the symptomatic cases, 87.5% of cases follow with satisfactory outcomes and 12.5% of cases follow with unexpected outcomes. The local spinal meningioma recurrence rate was 2.5% (1 of 40 cases). No postoperative cerebrospinal fluid leak occurred in the 40 spinal meningioma cases.A long-term postoperative follow-up indicated that this modified spinal dura preservation technique caused good neurologic improvement with rare recurrence. Therefore we recommend this improved technique may be an alternative surgical option for total resection of spinal meningiomas with favorable prognosis.

The pineal region and dorsal midbrain are among the most challenging surgical targets. To approach lesions in this region that harbor a superior to inferior long axis, we describe the basic steps of the precuneal, interhemispheric, trans-tentorial approach and illustrate anatomical landmarks of this established, but not so popular, surgical trajectory.To study the anatomical landmarks and safety of this approach, the neurovascular anatomy was studied on 22 sides of 11 formalin-fixed latex-injected anatomical specimens. A step-by-step dissection of the precuneal interhemispheric trans-tentorial approach and study of the key anatomical landmarks was performed. An illustrative clinical case of a pontomesencephalic cavernous malformation (CM) resected through this approach is also detailed.The mean distance from the transverse sinus to the most posterior cortical vein draining into the superior sagittal sinus was 6.4 cm. The mean distance from the calcarine sulcus to the most posterior cortical vein was 5.3 cm. Key steps of the dissection are as follows: craniotomy exposing the posterior aspect of the superior sagittal sinus (SSS), durotomy and gentle retraction of the SSS edge, dissection of the interhemispheric fissure, linear incision of the tentorium that extends anteriorly to the incisura and lateral reflection of the tentorium, and arachnoidal dissection and exposure of the cerebellomesencephalic fissure.The precuneal, interhemispheric, trans-tentorial approach affords excellent access to the falcotentorial junction, splenium, pineal region, quadrigeminal cistern, and dorsal pons once the cerebellomesencephalic fissure has been dissected.

Accurate biomechanical properties of the human dura mater are required for computational models and to fabricate artificial substitutes for transplantation and surgical training purposes. Here, a systematic literature review was performed to summarize the biomechanical properties of the human dura mater that are reported in the literature. Furthermore, anthropometric data, information regarding the mechanically tested samples, and specifications with respect to the used mechanical testing setup were extracted. A meta-analysis was performed to obtain the pooled mean estimate for the elastic modulus, ultimate tensile strength, and strain at maximum force. A total of 17 studies were deemed eligible, which focused on human cranial and spinal dura mater in 13 and 4 cases, respectively. Pooled mean estimates for the elastic modulus (n = 448), the ultimate tensile strength (n = 448), and the strain at maximum force (n = 431) of 68.1 MPa, 7.3 MPa and 14.4% were observed for native cranial dura mater. Gaps in the literature related to the extracted data were identified and future directions for mechanical characterizations of human dura mater were formulated. The main conclusion is that the most commonly used elastic modulus value of 31.5 MPa for the simulation of the human cranial dura mater in computational head models is likely an underestimation and an oversimplification given the morphological diversity of the tissue in different brain regions. Based on the here provided meta-analysis, a stiffer linear elastic modulus of 68 MPa was observed instead. However, further experimental data are essential to confirm its validity.

OBJECTIVE The discovery of dural lymphatics has spurred interest in the mechanisms of drainage of interstitial fluid from the CNS, the anatomical components involved in clearance of macromolecules from the brain, mechanisms of entry and exit of immune components, and how these pathways may be involved in neurodegenerative diseases and cancer metastasis. In this study the authors describe connections between a subset of arachnoid granulations (AGs) and the venous circulation via intradural vascular channels (IVCs), which stain positively with established lymphatic markers. The authors postulate that the AGs may serve as a component of the human brain’s lymphatic system. METHODS AGs and IVCs were examined by high-resolution dissection under stereoscope bilaterally in 8 fresh and formalin-fixed human cadaveric heads. The superior sagittal sinus (SSS) and adjacent dura mater were immunostained with antibodies against Lyve-1 (lymphatic marker), podoplanin (lymphatic marker), CD45 (panhematopoietic marker), and DAPI (nuclear marker). RESULTS AGs can be classified as intradural or interdural, depending on their location and site of drainage. Interdural AGs are distinct from the dura, adhere to arachnoid membranes, and occasionally open directly in the inferolateral wall or floor of the SSS, although some cross the infradural folds of the dura’s inner layer to meet with intradural AGs and IVCs. Intradural AGs are located within the leaflets of the dura. The total number of openings from the AGs, lateral lacunae, and cortical veins into the SSS was 45 ± 5.62 per head. On average each cadaveric head contained 6 ± 1.30 intradural AGs. Some intradural AGs do not directly open into the SSS and use IVCs to connect to the venous circulation. Using immunostaining methods, the authors demonstrate that these tubular channels stain positively with vascular and lymphatic markers (Lyve-1, podoplanin). CONCLUSIONS AGs consist of two subtypes with differing modes of drainage into the SSS. A subset of AGs located intradurally use tubular channels, which stain positively with vascular and lymphatic markers to connect to the venous lacunae and ultimately to the SSS. The present study suggests that AGs may function as a component of brain lymphatics. This finding has important clinical implications for cancer metastasis to and from the CNS and may shed light on mechanisms of altered clearance of macromolecules in the setting of neurodegenerative diseases.

OBJECTIVE Chronic adhesive spinal arachnoiditis (SA) is a complex disease process that results in spinal cord tethering, CSF flow blockage, intradural adhesions, spinal cord edema, and sometimes syringomyelia. When it is focal or restricted to fewer than 3 spinal segments, the disease responds well to open surgical approaches. More extensive arachnoiditis extending beyond 4 spinal segments has a much worse prognosis because of less adequate removal of adhesions and a higher propensity for postoperative scarring and retethering. Flexible neuroendoscopy can extend the longitudinal range of the surgical field with a minimalist approach. The authors present a cohort of patients with severe cervical and thoracic arachnoiditis and myelopathy who underwent flexible endoscopy to address arachnoiditis at spinal segments not exposed by open surgical intervention. These observations will inform subsequent efforts to improve the treatment of extensive arachnoiditis. METHODS Over a period of 3 years (2017–2020), 10 patients with progressive myelopathy were evaluated and treated for extensive SA. Seven patients had syringomyelia, 1 had spinal cord edema, and 2 had spinal cord distortion. Surgical intervention included 2- to 5-level thoracic laminectomy, microscopic lysis of adhesions, and then lysis of adhesions at adjacent spinal levels performed using a rigid or flexible endoscope. The mean follow-up was 5 months (range 2–15 months). Neurological function was examined using standard measures. MRI was used to assess syrinx resolution. RESULTS The mean length of syringes was 19.2 ± 10 cm, with a mean maximum diameter of 7.0 ± 2.9 mm. Patients underwent laminectomies averaging 3.7 ± 0.9 (range 2–5) levels in length followed by endoscopy, which expanded exposure by an average of another 2.4 extra segments (6.1 ± 4.0 levels total). Endoscopic dissection of extensive arachnoiditis in the dorsal subarachnoid space proceeded through a complex network of opaque arachnoidal bands and membranes bridging from the dorsal dura mater to the spinal cord. In less severely problematic areas, the arachnoid membrane was transparent and attached to the spinal cord through multifocal arachnoid adhesions bridging the subarachnoid space. The endoscope did not compress or injure the spinal cord. CONCLUSIONS Intrathecal endoscopy allowed visual assessment and safe removal of intradural adhesions beyond the laminectomy margins. Further development of this technique should improve its effectiveness in opening the subarachnoid space and untethering the spinal cord in cases of extensive chronic adhesive SA.

A chronic subdural haematoma (cSDH) is a collection of altered blood products between the dura and brain resulting in a slowly evolving neurological deficit. It is increasingly common and, in high income countries, affects an older, multimorbid population. With changing demographics improving the care of this cohort is of increasing importance.We convened a cross-disciplinary working group (the 'Improving Care in Elderly Neurosurgery Initiative') in October 2020. This comprised experts in neurosurgical care and a range of perioperative stakeholders. An Implementation Science framework was used to structure discussions around the challenges of cSDH care within the United Kingdom. The outcomes of these discussions were recorded and summarised, before being circulated to all attendees for comment and refinement.The working group identified four key requirements for improving cSDH care: (1) data, audit, and natural history; (2) evidence-based guidelines and pathways; (3) shared decision-making; and (4) an overarching quality improvement strategy. Frequent transfers between care providers were identified as impacting on both perioperative care and presenting a barrier to effective data collection and teamworking. Improvement initiatives must be cognizant of the complex, system-wide nature of the problem, and may require a combination of targeted trials at points of clinical equipoise (such as anesthetic technique or anticoagulant management), evidence-based guideline development, and a cycle of knowledge acquisition and implementation.The care of cSDH is a growing clinical problem. Lessons may be learned from the standardised pathways of care such as those as used in hip fracture and stroke. A defined care pathway for cSDH, encompassing perioperative care and rehabilitation, could plausibly improve patient outcomes but work remains to tailor such a pathway to cSDH care. The development of such a pathway at a national level should be a priority, and the focus of future work.

The lower bioavailability after oral administration limited icariin applications in central nervous system. Icariin/HP-β-cyclodextrin (HP-β-CD) inclusion complex was prepared for acute severe opening traumatic brain injury (TBI)

OBJECTIVE The optic nerve sheath diameter (ONSD) excluding the dura mater (ONSDE; i.e., the subarachnoid diameter) and the ONSD including the dura mater (ONSDI) have been used differently in studies, but the predictive ability of these two different measurements of the ONSD as measured by invasive intracranial pressure (ICP) monitoring has never been compared. Additionally, studies on the prediction of ICP using central retinal artery (CRA) Doppler ultrasonography are scarce. The authors aimed to determine how the two different ONSD measurements, the ONSD/eyeball transverse diameter (ETD) ratio, and transorbital Doppler ultrasonography parameters are associated with ICP via external ventricular drainage (EVD). METHODS This prospective observational study included 50 patients with brain injury who underwent EVD between August 2019 and September 2020. The mean of three repeated measurements of the ONSDI and ONSDE was calculated to reduce artifact and off-axis measurements. ETD, an immutable value, was measured from the initial brain CT with a clear outline of the eyeball. Simultaneously, flow velocities in the CRA and posterior ciliary artery (PCA) were compared with the ICP. RESULTS The ONSDE, ONSDI, and ONSD/ETD ratio were significantly associated with ICP (p = 0.005, p < 0.001, and p < 0.001, respectively). The ONSD/ETD ratio showed the highest predictive power of increased ICP (area under the curve [AUC] 0.897). The ONSDI was correlated more with the ICP than was the ONSDE (AUC 0.855 vs 0.783). None of the Doppler ultrasonography parameters in the CRA and PCA were associated with ICP. CONCLUSIONS The ONSD/ETD ratio is a better predictor of increased ICP compared with the ONSDI or ONSDE in brain-injured patients with nonsevere ICP. The ONSDI may be more available for predicting the ICP than the ONSDE.

International audience; A 59-year-old woman with no history of trauma presented with severe headaches and right-sided weakness. A CT scan showed a left hemispheric isodense subdural collection thought to be consistent with a subacute subdural hematoma (figure 1A). The patient underwent a single parietal burr hole for evacuation, but the neurosurgeon found subdural fleshy tissue and performed a biopsy. Immediate postoperative MRI showed a homogeneous hypercellular subdural mass (figure 1, B–F).1 Pathology was consistent with Burkitt lymphoma (figure 2). Retrospectively, the homogeneous density of the collection argued against hematoma. In nonemergent situations, an atypical radiologic appearance of a subdural hematoma may suggest the need for further radiologic investigations before surgical evacuation.2

OBJECTIVE Although evaluating tissue elasticity has various clinical applications, spinal cord elasticity (SCE) in humans has never been well documented. In this study, the authors aimed to evaluate the impact of compression on human SCE in vivo. METHODS The authors prospectively assessed SCE using intraoperative shear wave elastography (SWE). All consecutive patients undergoing spinal cord (SC) decompression (laminectomy or corpectomy) between June 2018 and June 2019 were included. After intraoperative exposure of the patient’s dura mater, at least three SWE measurements of the SC and its coverings were performed. Intraoperative neurological monitoring in the form of motor and somatosensory evoked potentials was utilized. Cases were divided into two groups based on the state of SC compression following bone removal (laminectomy or corpectomy): patients with adequate decompression (the decompressed SC group [DCG]) following bone removal and patients with remining compression, e.g., compressing tumor or instability (the compressed SC group [COG]). RESULTS A total of 25 patients were included (8 females and 17 males) with a mean age of 48.28 ± 21.47 years. Most cases were degenerative diseases (10 cases) followed by tumors (6 cases), and the compression was observed at cervical (n = 14), thoracic (n = 9), and conus medullaris (n = 2) levels. The COG (6 cases) expressed significantly higher elasticity values, i.e., greater stiffness (median 93.84, IQR 75.27–121.75 kPa) than the decompressed SC in DCG (median 9.35, IQR 6.95–11.22 kPa, p < 0.001). Similarly, the compressed dura mater in the COG was significantly stiffer (mean ± SD 121.83 ± 70.63 kPa) than that in the DCG (29.78 ± 18.31 kPa, p = 0.042). Following SC decompression in COG, SCE values were significantly reduced (p = 0.006; adjusted for multiple comparisons). Intraoperative monitoring demonstrated no worsening from the baseline. CONCLUSIONS The current study is to the authors’ knowledge the first to quantitatively demonstrate increased stiffness (i.e., elasticity value) of the human SC and dura mater in response to external compression in vivo. It appears that SCE is a dynamic phenomenon and is reduced following decompression. Moreover, the evaluation of human SCE using the SWE technique is feasible and safe. Information from future studies aiming to further define SCE could be valuable in the early and accurate diagnosis of the compressed SC.

The myodural bridge, that is, skeletal muscle fibers attaching to the cervical dura mater, has been described from a variety of mammals and other amniotes. To test an earlier assumption about the presence of the myodural bridge in snakes, a comparative study was designed using a group of Colubrine snakes. Serial histological sections revealed no evidence of the myodural bridge in any of the snakes examined. Further analyses, including histology, computed tomography (CT), and micro-CT imaging of other distantly related snakes, also turned up no evidence of a myodural bridge. The close apposition of adjacent neural arches in snakes may preclude muscle tendons from passing through the intervertebral joint to reach the spinal dura. It is hypothesized that the myodural bridge functions in the clearance of the cerebrospinal fluid (CSF) by creating episodic CSF pressure pulsations, and that snakes are capable of creating equivalent CSF pressure pulsations through vertebral displacement.

STUDY DESIGN Basic science study. OBJECTIVE The aim of this study was to examine whether epidural fat tissue (EFT) transplantation can prevent epidural adhesion after laminectomy more efficiently than subcutaneous fat tissue (SFT) transplantation. SUMMARY OF BACKGROUND DATA Epidural adhesion is almost inevitable after laminectomy. Although many materials have been used to prevent adhesion, none has been widely accepted. As EFT is an ectopic fat tissue located on the dura mater and there is no adhesion between EFT and the dura mater, we focused on the efficacy of EFT for adhesion prevention. METHODS We examined the differences in histology and gene expression between EFT and SFT of mice. We performed laminectomy at the 10th thoracic level and immediately transplanted EFT or SFT to the dura mater in mice. At six weeks after transplantation, we performed histological and gene expression analyses and evaluated the adhesion tenacity. In addition, we examined the characteristic differences between human EFT and SFT. RESULTS The adipocytes of EFT were significantly smaller than those of SFT in mice and humans. The gene expression of inflammatory cytokine and fibrosis-related factors was significantly higher in SFT than in EFT. At six weeks after transplantation, the percentage of the remaining fat area over the dura mater was significantly greater in the EFT group than in SFT group, and the adhesion tenacity score was significantly lower in the EFT group than that in the SFT group. An RNA sequencing analysis revealed 1921 differentially expressed genes (DEGs) between human EFT and SFT, and a Gene Ontology term associated with the inflammatory response was most highly enriched in SFT. CONCLUSIONS EFT has different molecular and histological profiles from SFT and EFT grafting is more effective for epidural adhesion prevention than conventional SFT transplantation after laminectomy in a mouse model.Level of Evidence: N/A.

This study aimed to assess the changes and values on follow-up computed tomography (F/U-CT) for isolated falcine (F-SDH) and tentorial (T-SDH) subdural hematomas (SDHs).Fifty-four cases of isolated F-SDH and/or T-SDH were retrospectively reviewed. Subdural hematoma morphology, mass effect on the adjacent parenchyma, and interval change at F/U-CT were evaluated. Subdural hematoma size was measured parallel and perpendicular to the falx/tentorium (long or short axis, respectively).Short-axis increase on F/U-CT was seen only in 5 F-SDHs (16%) and 7 T-SDHs (19%), with a maximum of a 2-mm increase. Long-axis growth was more prominent and frequent, seen in 18 F-SDH patients (56.2%) and 19 T-SDH patients (51.4%), with maximum change of up to 43 mm. Falcine SDH and T-SDH were ipsilateral and contiguous in 77.8% of patients. Minimal mass effect was seen in 13 patients (24.1%), which was resolved or stable on F/U-CT. Anticoagulation did not affect SDH size. No patients required neurosurgery or died.Based on our limited data, the current standard of F/U-CT may be unnecessary in patients with isolated F-SDH and/or T-SDH, which expand minimally along the short axis without a significant mass effect. Characteristic anatomic structure of the tentorium and falx, and their connectivity may direct SDH expansion and limit mass effect as well as injury to the adjacent parenchyma.

Reconstructive surgeries have long been considered as an essential part of rehabilitation of breast cancer patients. The majority of patients tend to choose one-stage reconstruction, because this type of surgery ensures rapid emotional and physical recovery. Due to the lack of subcutaneous fat in a substantial proportion of cases, which leads to postoperative complications, the most common surgical tactics now is simultaneous reconstruction after subcutaneous mastectomy with subpectoral implant location and strengthening of the lower breast slope using different materials. So far, there has been no gold standard material for secure covering of the lower pole of the implant. Autologous acellular dura mater grafts are a promising material for breast reconstruction. Studies evaluating biointegration, compatibility, inertness, reactivity, and cost effectiveness of autologous acellular dura mater grafts have determined feasibility of using these grafts in reconstructive surgeries.

OBJECTIVES To develop a novel grading system and appropriate surgical approaches for patients with diffuse type tensosynovial giant cell tumor (D-TGCT) of the temporal bone. STUDY DESIGN Retrospective cohort study. METHODS We retrospectively reviewed 31 patients with temporal bone D-TGCT between June 2012 and July 2021. All patients underwent comprehensive clinical evaluations, including clinical presentations, hearing threshold, imaging studies, surgical approaches, and prognosis. A grading system was developed based on the tumor location and adjacent neurovascular structures involvement according to imaging and intraoperative findings. RESULTS In this study, grade II tumors were the most common (13/31), followed by grades I (7/31), III (7/31), and IV (4/31) tumors. Seven grade I patients received the subtemporal middle cranial fossa approach (SMCF) combined with the canal wall up mastoidectomy and tympanoplasty (CWUT). Nine grade II patients underwent SMCF combined with subtotal petrosectomy (SPTR), and four grade II patients underwent SMCF combined with CWUT. Seven grade III patients received SMCF combined with SPTR and dura mater reconstruction, and four grade IV patients underwent infratemporal fossa approach type B. Gross total resection was achieved in all patients, and the median follow-up time was 30.1 months (range, 4-96 months). Three patients (one grade II, one grade III, and one grade IV) had recurrence during follow-up, and the patient with grade III tumor had two recurrences. CONCLUSIONS Gross total resection is the first-line treatment for patients with D-TGCT of the temporal bone. This novel grading system enables surgeons to select optimal surgical strategy. Long-term follow-up is mandatory postoperatively. LEVEL OF EVIDENCE 4 Laryngoscope, 2021.

Intracranial dural AVFs are abnormal communications between arteries that supply the dura mater and draining cortical veins or venous sinuses. They are believed to form as a response to venous insults such as thrombosis, trauma, or infection. Classification and management are dependent on the presence of drainage/reflux into cortical veins because such drainage markedly elevates the risk of hemorrhage or venous congestion, resulting in neurologic deficits. AVFs with tolerable symptoms and benign drainage patterns can be managed conservatively. Intolerable symptoms, presentation with hemorrhage/neurologic deficits, or aggressive drainage patterns are indications for intervention. Treatment options include microsurgical disconnection, endovascular transarterial embolization, transvenous embolization, or a combination. This is the first in a series of 3 articles on endovascular management of intracranial dural AVFs, in which we outline the principles and outcomes of endovascular treatment.

Cerebrospinal fluid (CSF) leak remains a significant source of morbidity after neurosurgical procedures. The objective is to evaluate the effectiveness and safety of a polyethylene glycol-coated collagen patch (PCC) in different neurosurgical procedures.A retrospective, single-center cohort study in patients who underwent a cranial neurosurgical procedure. After collecting multiple data variables, patients were divided into two groups depending on the use of PCC as sealant on dural closure following procedures.Data from 230 patients were collected (PCC, 128; control group, 102). Incidence of CSF leakage was significantly lower in the PCC group (p .001). Complications that were significantly lower in PCC than the control group included surgical infection (p = .022), and hydrocephalus (p = .017), as well as reduced rates of reintervention (p .001) and shorter hospital stays (p = .028). Factors associated with a higher incidence of CSF leakage included posterior fossa procedures, reinterventions, and the need for CSF drainage placement. PCC reduced the risk of suffering CSF leakage by more than 75% (p = .002) once adjusted for age, surgical approach, type of cranial opening, reintervention, CSF drainage, dural substitute, and dural defect coverage.Our findings confirm PCC as an effective means of preventing CSF leakage following cranial neurosurgery with fewer associated complications.

BACKGROUND Pericranial autograft is a popular option for duraplasty during Chiari decompression with several theoretical advantages, but comparisons to other materials have yielded mixed results. OBJECTIVE To compare outcomes between pericranial autograft and AlloDerm (BioHorizons). METHODS Consecutive suboccipital craniectomies for patients with type I Chiari malformation (CM-I) over an 8-yr period at a single institution were identified. Exclusion criteria included revision surgeries and suboccipital decompressions without duraplasty. Outcomes included incisional cerebrospinal fluid (CSF) leakage, length of stay (LOS), wound complication, aseptic meningitis, syrinx improvement, and symptomatic improvement. RESULTS A total of 101 patients (70 females and 31 males) with a median (interquartile range) age of 17 yr (11-32) met the inclusion criteria. There were 51 (50%) patients who underwent duraplasty with pericranial autograft, and the remainder underwent duraplasty with AlloDerm. There were 9 (9%) patients who experienced a postoperative CSF leak. After adjusting for confounding factors, obesity (odds ratio [OR]: 4.69, 95% CI: 1.03-25.6) and use of AlloDerm (OR: 10.54, 95% CI: 1.7-206.12) were associated with CSF leak. Wound complication occurred in 8 (8%) patients but was not associated with graft type (P = .8). Graft type was not associated with LOS, syrinx improvement, or symptom improvement. Reoperations occurred in 10 patients with 4 in the autograft group and 6 in the AlloDerm group (P = .71). CONCLUSION In patients with CM-I, expansile duraplasty with AlloDerm was associated with greater odds of CSF leakage than pericranial autograft. Obesity was also associated with increased odds of CSF leakage.

Background: The study hypothesis is that the knowledge about the mechanical properties of biological tissues will help surgeons to choose a transplant. Aim: To determine the optimal type of a graft, based on the assessment of the mechanical properties of three types of grafts used for the superior capsule reconstruction of the shoulder joint with a massive rotator cuff tear. Methods: In the experimental work, 3 types of biological tissues were studied: allografts of the fascia lata and of the dura mater, and the DX Reinforcement Matrix (a dermal ECM xenograft). The experiment was divided into two parts. In the first part, the mechanical strength at rupture of the samples was evaluated and compared, in the second part the resistance of a vertical suture was studied. The tests included uniaxial stretching with the force and strain at rupture recorded. Results: The fascia lata allograft showed the highest ultimate tensile strength, while the dura mater allograft had the lowest ultimate tensile strength. All the three materials showed rather high values of the rupture strain. The lowest value of the rupture strain was detected for the dura mater allograft 15.22.6%, the highest value was obtained for the dermal ECM xenograft 63.320.8%. The largest value of the fracture stress was recorded for the DX Reinforcement Matrix 33.5 N. The minimum value was recorded for the fascia lata allograft 9.9 N. Conclusion: The fascia lata allograft and DX Reinforcement Matrix have the optimal mechanical characteristics and can be recommended as grafts for the superior capsule reconstruction of the shoulder joint with a massive rotator cuff tear.

OBJECTIVE Torcular dural sinus malformations (tDSMs) are rare pediatric cerebrovascular malformations characterized by giant venous lakes localized to the midline confluence of sinuses. Historical clinical outcomes of patients with these lesions were poor, though better prognoses have been reported in the more recent literature. Long-term outcomes in children with tDSMs are uncertain and require further characterization. The goal of this study was to review a cohort of tDSM patients with an emphasis on long-term outcomes and to describe the treatment strategy. METHODS This study is a single-center retrospective review of a prospectively maintained data bank including patients referred to and cared for at The Hospital for Sick Children for tDSM from January 1996 to March 2019. Each patient’s clinical, radiological, and demographic information, as well as their mother’s demographic information, was collected for review. RESULTS Ten patients with tDSM, with a mean follow-up of 58 months, were included in the study. Diagnoses were made antenatally in 8 patients, and among those cases, 4 families opted for either elective termination (n = 1) or no further care following delivery (n = 3). Of the 6 patients treated, 5 had a favorable long-term neurological outcome, and follow-up imaging demonstrated a decrease or stability in the size of the tDSM over time. Staged embolization was performed in 3 patients, and anticoagulation was utilized in 5 treated patients. CONCLUSIONS The authors add to a growing body of literature indicating that clinical outcomes in tDSM may not be as poor as initially perceived. Greater awareness of the lesion’s natural history and pathophysiology, advancing endovascular techniques, and individualized anticoagulation regimens may lead to continued improvement in outcomes.

Cerebral spinal fluid (CSF) leakage is a major postoperative complication requiring surgical intervention, resulting in prolonged healing and higher costs. Biocompatible polymers, such as cyanoacrylates, are currently used as tissue adhesives for closing surgical defects and incisions. Coupling these polymers with nanofiber technology shows promising results for generating nanofibers used in wound care, tissue engineering, and drug delivery. Fiber membranes formed by electrospinning of n-octyl-2-cyanoacrylate (NOCA) are investigated for in situ dural closures after neurosurgery to improve the quality of the closure and prevent post-surgical CSF leaks. Electrospun NOCA fiber membranes showed significantly higher sealing capabilities of defects in human dura, with an average burst pressure of 149 mmHg, compared with that of an FDA-approved common dural sealant that had an average burst pressure of 37 mmHg. In this study, microfabrication of NOCA fibers demonstrates a promising technique for dural repairs.

The current surgical management of adult Chiari malformation type I (CM-I) with associated syringomyelia remains controversial. The objective of this study was to explore posterior fossa decompression and duraplasty (PFDD) with and without tonsillar resection in adult patients with CM-I and syringomyelia.A total of 116 adult patients suffering from both CM-I and syringomyelia who were scheduled to undergo surgical decompression at our institution between 2012 and 2020 were randomly divided into 2 groups: the PFDD group (n = 64) underwent PFDD without tonsillar resection, while the PFDD-T group (n = 52) underwent PFDD with tonsillar resection. The primary outcome was improvement or resolution of the syrinx. The secondary outcome was an improvement in clinical outcome based on Chicago Chiari Outcome Scale (CCOS) scores. All participants were followed-up to 1-year postoperatively.The proportions of patients who had20% improvement in syrinx size were 60.9% and 78.8% in the PFDD and PFDD-T groups, respectively (P = .038). The improvement in clinical outcome based on CCOS scores was significantly different in the 2 groups (P = .004). The functionality sub-score was significantly different between the 2 groups (P = .027), but there were no significant differences in the pain symptoms, non-pain symptoms, and complications sub-scores. The total CCOS scores were higher in the PFDD-T group than in the PFDD group (P = .037).This study determined the role of tonsillar resection in achieving obvious syrinx improvement following PFDD-T. PFDD with tonsillar resection seems to be a safe and effective surgical option to treat adult CM-I patients with syringomyelia.

Arachnoid granulations (AG) are poorly investigated. Historical reports suggest that they regulate brain volume by passively transporting cerebrospinal fluid (CSF) into dural venous sinuses. Here, we studied the microstructure of cerebral AG in humans with the aim of understanding their roles in physiology. We discovered marked variations in AG size, lobation, location, content, and degree of surface encapsulation. High-resolution microscopy shows that AG consist of outer capsule and inner stromal core regions. The fine and porous framework suggests uncharacterized functions of AG in mechanical CSF filtration. Moreover, internal cytokine and immune cell enrichment imply unexplored neuroimmune properties of these structures that localize to the brain–meningeal lymphatic interface. Dramatic age-associated changes in AG structure are additionally identified. This study depicts for the first time microscopic networks of internal channels that communicate with perisinus spaces, suggesting that AG subserve important functions as transarachnoidal flow passageways. These data raise new theories regarding glymphatic–lymphatic coupling and mechanisms of CSF antigen clearance, homeostasis, and diseases.

Meningomyelocele is the most common disease of the spina bifida, and repair surgery is recommended within the first 48 hours of life to prevent infection and secondary neurological damage. The basic surgical approach is a five-layer closure that closes the five layers of the spinal cord, dura matter, fascia, subcutaneous tissue, and skin. Comprehending the relationship between normal anatomy of the spinal cord and myelomeningocele is key. In this section, we discuss the basic repair surgery of meningomyelocele by describing the surgery of lumbosacral meningomyelocele.

Posterior fossa decompression (PFD) with/without duraplasty is the standard surgical treatment for symptomatic CM-1. Posterior fossa decompression without duraplasty (PFD) may be associated with shorter operative times and hospital stays, fewer complications, and may yield improvements in symptoms and syrinx sizes. Posterior fossa decompression with duraplasty (PFDD) may be associated with superior long-term symptomatic improvements, larger syrinx reductions, and a lower need for revision decompression. Various dural graft materials may be used for PFDD, though the ideal type of graft has not been definitively established. Other adjunct surgical procedures may be added to PFD/PFDD given certain symptomatic or anatomical considerations.

Chiari 1 malformation has crowding at craniovertebral junction (CVJ), treated by Foramen magnum decompression (FMD) but is associated with high failure rates, which is explained by recently introduced concept of central instability. So, we propose a new concept of relieving this crowding without affecting stability.To derive a threshold for coring out of internal surface of C1 posterior arch instead of complete laminectomy accompanying FMD.We prospectively included nine patients with a mean age of 25.33 ± 7.97 years, diagnosed with ACM-1 without AAD, who were operated with FMD and lax duraplasty and C1 laminectomy. The preoperative dural diameter and area covered under the dura at the level of C1 were measured and compared with the postoperative state. Results were analyzed to derive a cut-off threshold which could be drilled from the inner aspect of C1 arch.The postoperative AP diameter of the dura increased statistically significantly from pre-op; however, the AP extension was less than the preoperative diameter with posterior arch included. Likewise, the area spanned by the dura increased statistically significantly from pre-op but was less than the cumulative area of dura with C1 arch included in pre-op. Analyzing all, a mean cut-off of 50.58% was achieved.The authors suggest FMD with partial coring (~50%) of the inner part of arch of C1, instead of full-thickness laminectomy with a wider length of coring as the target, and this will serve the purpose intended, without increasing mobility.

Objective The purpose of this study is to explore whether electrical impedance tomography (EIT)-guided individualized positive end-expiratory pressure (PEEP) can reduce the incidence of pulmonary complications within 1 week following a craniotomy compared with a single PEEP (PEEP = 6 cmH2O) from dura suturing to extubation. Methods A randomized controlled trial will be conducted at the Second Affiliated Hospital of Soochou University. Five hundred forty patients undergoing a craniotomy in the supine position will be randomly allocated into the P6 (PEEP = 6 cmH2O) or Pi (individualized PEEP) group. Both groups of patients will receive a lung recruitment maneuver before suturing the dura. Then, the P6 group will receive 6 cmH2O PEEP, and the Pi group will receive EIT-guided individualized PEEP. The incidence and severity score of pulmonary complications within 1 week following surgery, the lung ultrasound score (LUS), regional cerebral oxygen saturation (rScO2), and PaO2/FiO2 before anesthesia (T0), 10 min after extubation (T1), 24 h after extubation (T2), and 72 h after extubation (T3) will be compared between the two groups. The duration of surgery and anesthesia, the level and duration of PEEP during surgery, the volume of liquid intake and output during surgery, and the postoperative ICU and hospital stays will be recorded. The main outcome of this study will be the incidence of pulmonary complications within 1 week after surgery. Discussion The purposes of this study are to determine whether EIT-guided individualized PEEP from the beginning of dura suturing to extubation reduces the incidence of pulmonary complications within 1 week after a craniotomy compared with a single constant PEEP and to evaluate the length of ICU and hospital stays. If our results are positive, this study will show that EIT-guided individualized PEEP is better than a single constant PEEP and can further improve the prognosis of neurosurgical patients and reduce hospitalization costs, which will promote the wide application of individualized PEEP in clinical anesthesia. Trial registration Chinese Clinical Trial Registry CHiCTR2100051200. Registered on 15 September 2021.

STUDY DESIGN Retrospective study. OBJECTIVE To determine the risk factors for insufficient recovery from C5 palsy (C5P) following anterior cervical decompression and fusion (ADF). SUMMARY OF BACKGROUND DATA Postoperative C5P is a frequent but unsolved complication following cervical decompression surgery. Although most patients gradually recover, some recover only partially. When we encounter new-onset C5P following ADF, the question that often arises is whether the palsy will sufficiently resolve. METHODS We retrospectively reviewed consecutive patients who underwent ADF at our institution. We defined C5P as postoperative deterioration of deltoid muscle strength by two or more grades determined by manual muscle testing (MMT). We evaluated the following demographic data: patient factors, surgical factors, and radiological findings. C5P patients were divided into two groups: sufficient recovery (MMT grade≧4) and insufficient recovery (MMT grade

Capsaicin is able to induce mast cell degranulation, an event probably related to the pathophysiologyof a migraine attack. The present review study aimed to address the mechanisms of action of capsaicin and other chemical inducers in mast cell degranulation and an interaction of nerves and events that happen in the dura mater with the activation of mast cells. A survey was carried out in the literature, from 1980 to 2019, in different databases, using the following terms: capsaicin, mast cell and dura mater. 36 articles were selected for this review. Studies indicate that the main mechanisms of action of capsaicin are chemical induction through the activation of TRPV1 channels,allowing calcium influx into neurons in the trigeminal ganglion of the dura mater, activating mast cell degranulation, releasing pro-inflammatory (e.g., histamine, oxide nitric) and vasoactive (e.g., CGRP and substance P) substances. Therefore, the use of capsaicin may be a tool to be used in an animal model to better understand the pathophysiology of migraine.

C342Y (Cys342Tyr) point mutation of FGFR2 (fibroblast growth factor receptor 2) is closely associated with the pathogenesis of Crouzon syndrome. The dura mater plays an important role in mediating the closure of cranial sutures. However, the underlying mechanisms of these pathological processes have been rarely investigated. in this study, the authors analyzed the effects of dura cells with FGFR2 mutations on the biological function of osteoblasts.Dura cells and cranial osteoblasts from C57BL/6 mice were extracted and cultured. C342Y-FGFR2 mutant constructs were established via lentivirus and applied to infect dura cells. A co-cultured trans-well system with dura cells and osteoblasts was established. Three experimental groups were set up: oste group, Oste + Dura-vector group, and Oste + Dura-C342Y group. The expression levels of key factors in MEK (Mitogen-activated protein kinase kinase, MAPKK)/extracellular signal-regulated kinase (ERK) and Hippo pathway were detected by western blot and RT-qPCR (Real Time Quantitative PCR). Finally, a rescue experiment was carried out with small interference RUA.The proliferation level of osteoblasts in Oste + Dura- C342Y group was significantly up-regulated. Our studies indicated that the activation of MEK/ERK pathway in Oste + Dura-C342Y group could inhibit the Hippo pathway, lead to down-regulation of large tumor suppressor 1 and promote the activation and nuclear localization of yes-associated protein, and the results of rescue experiments showed a reverse expression trend, further confirming the effects of C342Y-FGFR2 mutation in dura cells on osteoblasts and its potential mechanism.This study suggested that the C342Y-FGFR2 mutation in dura cells could promote osteoblastic proliferation, and shown the crosstalk between MEK/ERK and Hippo pathways. As the regulatory machinery center, yes-associated protein might play a bridging role in these pathways, and might influence the pathogenesis of craniosynostosis by activating downstream transcriptional factors.

The maxillary artery (MA) is one of the terminal branches of the external carotid artery (ECA) and through its branches, it is responsible for vascularizing several organs and muscles of the head and neck, including their surrounding soft tissues, the oral and sinonasal cavities, dura mater, and various cranial nerves. The aim of this study was to conduct a systematic review and meta-analysis of maxillary artery anatomy according to the Anatomical Quality Assurance (AQUA) checklist. We conducted a systematic search through PubMed, EMBASE, Scopus, ScienceDirect, Web of Science, SciELO, Springerlink, WILEY and BIREME databases. We applied the Anatomical Quality Assurance (AQUA) checklist for analysis the methodological quality of the articles. From a total of 11,759 articles found in the first search, and after applying the inclusion/exclusion criteria, in addition to eliminating duplicate articles, a final number of 24 articles were identified. The information on the maxillary artery was analyzed from each study regarding its course in relation to the lateral pterygoid muscle, the intra- and extraluminal diameters of the maxillary artery and its branches, and the types of branching of the maxillary artery in the pterygopalatine fossa. From this study, it was possible to conclude the importance of anatomical knowledge of the maxillary artery, for its application in the clinical study of the head and neck, as well as the need to apply the AQUA checklist in the development of systematic anatomical reviews to ensure accurate reliability and a better assessment of the effect of anatomical publications.

OBJECTIVE Isolated anterior cerebral artery (ACA) territory ischemia in pediatric moyamoya disease (MMD) is rare but has been increasingly recognized, particularly in children manifesting progression of disease in a delayed fashion after middle cerebral artery revascularization surgery. Surgical treatment is complicated by limited graft choices, with the small number of case series largely focused on complex, higher-risk operations (omental flap transfers, large interhemispheric rotational grafts); direct bypass (often untenable in children due to vessel size); or, alternatively, the technically simpler method of multiple burr holes (of limited efficacy outside of infants). Faced with the problem of a growing cohort of pediatric patients with MMD that could benefit from anterior cerebral revascularization, the authors sought to develop a solution that was specifically designed for children and that would be lower risk than the more complex approaches adapted from adult populations but more effective than simple burr holes. In this study, the authors aimed to describe the long-term clinical and radiographic outcomes of a novel approach of pial pericranial dural (PiPeD) revascularization, building on the principles of pial synangiosis but unique in using the pericranium and the dura mater as the primary vascular supply, and employing a larger craniotomy with arachnoid dissection to provide robust full-territory revascularization in all ages with reduced risk relative to more complex procedures. METHODS The medical records of all pediatric patients with MMD who presented at a single center between July 2009 and August 2019 were retrospectively reviewed to identify patients with MMD with anterior cerebral territory ischemia. Clinical characteristics, surgical indications, operative techniques, and long-term clinical and radiographic follow-up data were collected and analyzed. RESULTS A total of 25 operations (5.6% of total procedures) were performed in 21 patients (mean age 9.4 years [range 1–16.5 years]; 12 female and 9 male). Almost one-third of the patients had syndromic associations, with no familial cases. Complications included 1 patient (4.7%) with a superficial infection, with no postoperative strokes, hemorrhage, seizures, or deaths. Long-term follow-up was available in 18 of 21 patients (mean 24.9 months [range 4–60 months]). Radiographic engraftment was present in 90.9% (20/22 hemispheres), and no new strokes were evident on MRI on long-term follow-up, despite radiographic progression of the disease. CONCLUSIONS The use of the pericranium and the dura mater for indirect revascularization provided robust vascularized graft with great flexibility in location and high potential for engraftment, which may obviate more complex and higher-risk operations for ACA territory ischemia. Long-term follow-up demonstrated that PiPeD revascularization conferred durable, long-term radiographic and clinical protection from stroke in pediatric patients with MMD. Based on the results of the current study, the PiPeD technique can be considered an additional tool to the armamentarium of indirect revascularization procedures in select pediatric patients with MMD.

In mucopolysaccharidoses (MPS), spinal cord compression (SCC) resulting from glycosaminoglycan (GAG) accumulation is a critical complication that can cause significant neurological and respiratory morbidities. However, clinically similar disorders such as mucolipidosis types II and III (ML) with SCC have been scarcely reported. Herein, we report four patients with ML who had SCC. Brain MRI revealed progressive spinal canal stenosis and SCC. In addition, T2-weighted high signal changes in the cervical cord were detected in two cases. Severe cases of SCC were detected as early as 1 year of age. All cases had respiratory problems. One case showed severe hypoxia and another, severe sleep apnea. In two cases, respiratory insufficiency and tetraplegia rapidly progressed as SCC progressed. Then, the patients became bedridden and needed artificial ventilation. In addition, two of the four patients died of respiratory failure. The autopsy of one patient revealed a compressed cervical cord and marked dura mater thickening due to GAG accumulation. These findings suggest that the accumulation of substrates in the dura mater caused SCC in the patients with ML. Our cases indicate that SCC is expected to be a common and critical complication of ML and MPS. MRI evaluation of cervical involvements and careful clinical observation are required in patients with ML.

A malignancy is a fatal condition that could occur through various mechanisms. Forensic pathologists sometimes find unexpected findings during autopsy and post-mortem (PM) tests. Colorectal cancer is one of the leading causes of cancer-related deaths worldwide. The deceased was a 64-year-old man with a medical history of right hemicolectomy due to colon cancer approximately two years earlier. He was found dead at his home. He was admitted to the hospital due to subdural hemorrhage (SDH) two days prior to his demise and was discharged without the permission of the doctor after one day of hospitalization. An autopsy was performed within two days of his death. After gross dissection, the cause and manner of death were assumed to be SDH and unnatural death, respectively. Microscopic examination revealed fresh SDH and dural metastasis of signet-ring cell carcinoma. Furthermore, metastasis was identified in the heart, stomach, and peritoneum. Immunohistochemical examination revealed cancer cells to originate from the colon. After meticulous PM examination, including gross dissection, microscopic examination, PM computed tomography, and PM laboratory tests, the cause and manner of death were determined as SDH and natural death, respectively. This case report highlights the importance of comprehensive PM evaluation for investigating death.

Spontaneous intracranial hypotension (SIH) is secondary to a cerebrospinal fluid leak at the spinal level without obvious causative events. Several signs on brain and cervical spine magnetic resonance (MR) imaging (MRI) have been associated with SIH but can be equivocal or negative. This retrospective study sought to identify characteristic SIH signs on thoracic spinal MRI. Cranial and spinal MR images of 27 consecutive patients with classic SIH symptoms, who eventually received epidural autologous blood patches (EBPs), were analyzed. The most prevalent findings on T2-weighted MRI at the thoracic level were anterior shift of the spinal cord (96.3%) and dorsal dura mater (81.5%), probably caused by dural sac shrinkage. These dural sac shrinkage signs (DSSS) were frequently accompanied by cerebrospinal fluid collection in the posterior epidural space (77.8%) and a prominent epidural venous plexus (77.8%). These findings disappeared in all six patients who underwent post-EBP spinal MRI. Dural enhancement and brain sagging were minimum or absent on the cranial MR images of seven patients, although DSSS were obvious in these seven patients. For 23 patients with SIH and 28 healthy volunteers, a diagnostic test using thoracic MRI was performed by 13 experts to validate the usefulness of DSSS. The median sensitivity, specificity, positive-predictive value, negative-predictive value, and accuracy of the DSSS were high (range, 0.913–0.931). Detection of DSSS on thoracic MRI facilitates an SIH diagnosis without the use of invasive imaging modalities. The DSSS were positive even in patients in whom classic cranial MRI signs for SIH were equivocal or minimal.