Spinal Dura Research Articles

Multiple lumbar spinal inter-dural cysts

Abstract Introduction: Cysts of the spinal canal may be located in the extradural or intradural space. Distinct from these cysts, inter-dural spinal cysts form between the two layers of the spinal dura and contain fluid, including cerebrospinal fluid (CSF) and blood. Inter-dural spinal cysts are extremely rare. We recently encountered a patient presenting with a multiple lumbar spinal inter-dural cysts. Patient concerns: A 58-year-old woman presented with an acute onset of back pain radiating to her left leg. She had no history of surgery or trauma and no other medical illness. Her pain was not relieved by considerable attempts to control it through medication or physical therapy Diagnosis: The magnetic resonance imaging indicated multiple cystic lesions ventral and dorsal to the thecal sac at L2/3 which were compressing the roots of the cauda equina. The contents of the ventral lesion were relatively high signal on T2-weighted images and low-signal on T1-weighted images, suggesting a CSF. Additional magnetic resonsnce myelography was highly suggestive of multiple isolated cysts located in the inter-dural space, with a thin wall separated from the CSF. Interventions: The patient underwent total laminectomy of the 2nd to 3rd lumbar vertebral to expose the cyst. After midline dural incision, inner dural leaflet was found and we could have confirmed the exact position of the cyst was interdural space, and the inner dura was excised. We then retracted the rootlets to find another ventral cyst. A small incision was made in the inner dura overlying the ventral cyst and yellowish fluid was drained. Complete cyst fenestration and excision of the inner dural leaflet was performed. Outcomes: A histopathology report confirmed the cyst to be dura. The patient had complete resolution of symptoms and was asymptomatic 3 years after surgery. Conclusions: Inter-dural cysts occur very rarely. We report the first case of multiple lumbar spinal inter-dural cysts. Acknowledging inter-dural spinal cysts as a type of spinal meningeal cyst is imperative, as this will allow surgeons to avoid unnecessary dural breaches and associated complications.

The morphology of the suboccipital region in snakes, and the anatomical and functional diversity of the myodural bridge.

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.

Not All Lectins Are Equally Suitable for Labeling Rodent Vasculature.

The vascular system is vital for all tissues and the interest in its visualization spans many fields. A number of different plant-derived lectins are used for detection of vasculature; however, studies performing direct comparison of the labeling efficacy of different lectins and techniques are lacking. In this study, we compared the labeling efficacy of three lectins: Griffonia simplicifolia isolectin B4 (IB4); wheat germ agglutinin (WGA), and Lycopersicon esculentum agglutinin (LEA). The LEA lectin was identified as being far superior to the IB4 and WGA lectins in histological labeling of blood vessels in brain sections. A similar signal-to-noise ratio was achieved with high concentrations of the WGA lectin injected during intracardial perfusion. Lectins were also suitable for labeling vasculature in other tissues, including spinal cord, dura mater, heart, skeletal muscle, kidney, and liver tissues. In uninjured tissues, the LEA lectin was as accurate as the Tie2–eGFP reporter mice and GLUT-1 immunohistochemistry for labeling the cerebral vasculature, validating its specificity and sensitivity. However, in pathological situations, e.g., in stroke, the sensitivity of the LEA lectin decreases dramatically, limiting its applicability in such studies. This work can be used for selecting the type of lectin and labeling method for various tissues.

Novel Dural-Splitting Operative Technique for Excision of Ventrally Located Spinal Meningiomas

Spinal meningiomas are one of the frequently seen intradural extramedullary spinal tumors. They are almost always World Health Organization grade I, and a complete removal of the tumor can be curative. However, ventrally located spinal meningioma removal can be challenging due to the position in front of the spinal cord through a narrow corridor provided by routine dorsal approaches. Incomplete excision of the relatively inaccessible dural attachment can consequently lead to recurrence. We describe a safe and reproducible technique used to achieve Simpson grade I removal of ventrally located spinal meningioma. Since the spinal dura can be easily divided into inner and outer layers and the tumor usually spares the outer layer, we developed a simple technique to achieve total resection of the tumor and involved dura while leaving the outer dural layer intact. An advantage of this procedure is that it exploits an interdural approach to allow early devascularization of the tumor without cord manipulation and provides access to the ventral dura to achieve Simpson grade I excision. Another advantage is complete dural closure to minimize postoperative cerebrospinal fluid leak or ventral cord herniation without the need for dural substitutes. Its novel interdural approach can be used for all ages and all spinal meningiomas.

Dural sac shrinkage signs on magnetic resonance imaging at the thoracic level in spontaneous intracranial hypotension-its clinical significance.

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.

A specialized myodural bridge named occipital-dural muscle in the narrow-ridged finless porpoise (Neophocaena asiaeorientalis)

A dense bridge-like tissue named the myodural bridge (MDB) connecting the suboccipital muscles to the spinal dura mater was originally discovered in humans. However, recent animal studies have revealed that the MDB appears to be an evolutionarily conserved anatomic structure which may have significant physiological functions. Our previous investigations have confirmed the existence of the MDB in finless porpoises. The present authors conducted research to expound on the specificity of the MDB in the porpoise Neophocana asiaeorientalis (N.asiaeorientalis). Five carcasses of N.asiaeorientalis, with formalin fixation, were used for the present study. Two of the carcasses were used for head and neck CT scanning, three-dimensional reconstructions, and gross dissection of the suboccipital region. Another carcass was used for a P45 plastination study. Also, a carcass was used for a histological analysis of the suboccipital region and also one was used for a Scanning Electron Microscopy study. The results revealed that the MDB of the N.asiaeorientalis is actually an independent muscle originating from the caudal border of the occiput, passing through the posterior atlanto-occipital interspace, and then attaches to the cervical spinal dura mater. Thus the so called MDB of the N.asiaeorientalis is actually an independent and uniquely specialized muscle. Based on the origin and insertion of this muscle, the present authors name it the ‘Occipital-Dural Muscle’. It appears that the direct pull of this muscle on the cervical spinal dura mater may affect the circulation of the cerebrospinal fluid by altering the volume of the subarachnoid space via a pumping action.

Head-nodding: a driving force for the circulation of cerebrospinal fluid

The myodural bridge (MDB) is a dense connective tissue bridge connecting the suboccipital muscles to the spinal dura mater, and it has been proven to be a normal common existing structure in humans and mammals. Some scholars believe that the suboccipital muscles can serve as a dynamic cerebrospinal fluid (CSF) pump via the MDB, and they found head rotations promote the CSF flow in human body, which provided evidence for this hypothesis. Head movement is a complex motion, but the effects of other forms of head movement on CSF circulation are less known. The present study explored the effects of head-nodding on CSF circulation. The CSF flow of 60 healthy volunteers was analyzed via cine phase-contrast magnetic resonance imaging at the level of the occipitocervical junction before and after one-minute-head-nodding period. Furthermore, the CSF pressures of 100 volunteers were measured via lumbar puncture before and after 5 times head-nodding during their anesthetizing for surgical preparation. As a result, it was found that the maximum and average CSF flow rates at the level of the upper border of atlas during ventricular diastole were significantly decreased from 1.965 ± 0.531 to 1.839 ± 0.460 ml/s and from 0.702 ± 0.253 to 0.606 ± 0.228 ml/s respectively. In the meantime, the changes in the ratio of cranial and caudal orientation of the net flow volume were found differed significantly after the one-minute-head-nodding period (p = 0.017). And on the other hand, the CSF pressures at the L3–L4 level were markedly increased 116.03 ± 26.13 to 124.64 ± 26.18 mmH2O. In conclusion, the head-nodding has obvious effects on CSF circulation and head movement is one of the important drivers of cerebrospinal fluid circulation. We propose that the suboccipital muscles, participating in various head movements, might pull the dura sac via the myodural bridge, and thus, head movement provides power for the CSF circulation.

Assessment of potential strain injury to rectus capitis posterior minor muscles during whiplash type distortions of the cervical spine.

Whiplash type injuries resulting from a rear end motor vehicle accident (REMVA) are thought to be caused by excessive loading and displacement of structural components of the cervical spine. On impact, the seat propels the driver's torso forward relative to the head, resulting in forced flexion of the occipitoatlantal (OA) joint, accompanied by forced stretching of the rectus capitis posterior minor (RCPm) muscles. Flexion of the OA joint and stretching of the RCPm muscles continues to increase until the vehicle's headrest strikes the back of the driver's head. It is known that externally applied forces that attempt to move the OA joint beyond its anatomic barrier can result in fracture, dislocation, or soft tissue damage to its structural components. However, the magnitude of headrest backset, defined as the distance between the driver's head and the vehicle's headrest, that would result in RCPm muscles being stretched to a length that would put them at risk for a muscle strain injury is unknown. To quantify the relationships among flexion of the OA joint, RCPm muscle stretch, and backset, and to quantify the biomechanical response of RCPm muscles to increasing levels of axial load due to stretching. Unembalmed head and neck specimens from three White females aged 85, 63, and 70 years were obtained from the Anatomical Services Division at the University of Maryland. Donors had provided written consent allowing use of their body for research purposes. Using an analytic model of the OA joint, the relationships between flexion of the OA joint and RCPm muscle stretch as a function of backset were estimated. RCPm muscles were removed from the cadavers and forcibly stretched using a servomechanism controlled hydraulic testing machine to quantify the load/displacement properties. After testing, the tissues were sectioned, mounted, and stained using Masson's trichrome to selectively stain muscle fibers red and collagen blue. Forced flexion of the OA joint was seen to be directly related to the magnitude of headrest backset. For values of backset greater than 7.2cm, biomechanical testing of the RCPm muscles revealed that strain injuries ranged from the tearing of a few muscle fibers to complete rupture of the muscle and separation of the tendon at the posterior process of C1. Results showed that headrest backset at the time of vehicle impact is an important factor in estimating the risk of muscle strain injury to RCPm muscles. Muscle strain injury would be expected to impact the functional relationship between the RCPm muscles and the pain sensitive spinal dura. Physicians should be alert to the possibility that cervicogenic pain patients who have experienced whiplash associated with REMVA may show clinically relevant structural damage to the RCPm muscles on MRI.

P.136 All that fits isn’t eclampsia

Introduction: Intracranial subdural haematoma (ISH) due to inadvertent puncture of the spinal dura mater following central neuraxial blockade is exceedingly rare, with fewer than 100 cases reported. [1] Szeto V, Kosirog J, Eilbert W. Intracranial subdural hematoma after epidural anesthesia: a case report and review of the literature. Int J Emerg Med 2018; 11:36. Google Scholar In obstetrics, ISH secondary to epidural anaesthesia is around 1:500,000. [1] Szeto V, Kosirog J, Eilbert W. Intracranial subdural hematoma after epidural anesthesia: a case report and review of the literature. Int J Emerg Med 2018; 11:36. Google Scholar We present an obstetric case exemplifying these consequences, ultimately presenting with seizure, also revealing an undiagnosed cerebral structural abnormality.

Investigation of a Novel Cranial Ligament Between the Occiput and Cervical Spinal Dura

Introduction The brain and spinal cord are covered by dura mater which attaches to bones and muscles in the cervical region. Dural connective structures have been described as the Ligamentum Craniale Durae Matrice Spinalis (LCDMS) (Von Lanz, 1929). The myodural bridge complex (MBC) is a component of the LCDMS linking suboccipital musculature to the cervical spinal dura. While performing en bloc dissections of the central nervous system, we found a novel connection between the occiput and the cervical spinal dura that has not been previously described that we have termed, the ligamentum kryptos craniale (LKC). In this study, we provide evidence that the LKC is a previously unrecognized component of the LCDMS. Methods A total of 13 cadavers were dissected. Total spinal laminectomy and en bloc dissection was performed on two cadavers, and the occiput was removed via a coronal cut with inferior borders meeting the lateral most aspect of the foramen magnum. Eleven different cadaver skulls were cut at the euryon in transverse section. Five of the 11 cadavers were hemisected to the level of C5. LKC Length from origin to opisthion, thicknesses at opisthion, length from opisthion to cervical dura, and width at opisthion were measured. All measurements were taken with Mitutoyo Absolute IP-67 digital calipers except for LKC width, in which a flexible ruler was used. Photograph evidence was also obtained, and statistical analysis was conducted using Microsoft Excel. Results The LKC was found in all bodies (13 specimens). Its shape was triangular as it exited the foramen magnum and inserted onto the cervical spinal dura (Fig. 1). Its origin spanned across the internal occipital crest, the inferior ridge of the cerebellar fossa, and the opisthion (Fig. 2). Various measurements of the LKCs were made (expressed as means + SD) including the length from origin to opisthion (1.94 ± 0.3 cm, N = 10), thickness at opisthion (0.58 ± 0.05 mm, N = 6), length from opisthion to cervical dura (10.51 ± 2.59 mm, N = 5) and width at opisthion (5.05 ± 0.44 cm, N = 10). Conclusion Based on the findings of this study, we believe the LKC is a novel component of the LCDMS. Data suggests the MBC attaches to the LKC rather than directly to the cervical spinal dura mater. In the clinical setting, the LKC may be relevant to unknown causes of head and neck pain. Future histological studies and microscopic analysis will be necessary to further categorize this structure. References von Lanz, T. (Jun 1929). Über die Rückenmarkshäute : I. Die Konstruktive Form der harten Haut des menschlichen Rückenmarkes und ihrer Bänder. 118, 252-307.

The morphology, biomechanics, and physiological function of the suboccipital myodural connections

The myodural bridge (MDB) connects the suboccipital musculature to the spinal dura mater (SDM) as it passed through the posterior atlanto-occipital and the atlanto-axial interspaces. Although the actual function of the MDB is not understood at this time, it has recently been proposed that head movement may assist in powering the movement of cerebrospinal fluid (CSF) via muscular tension transmitted to the SDM via the MDB. But there is little information about it. The present study utilized dogs as the experimental model to explore the MDB’s effects on the CSF pressure (CSFP) during stimulated contractions of the suboccipital muscles as well as during manipulated movements of the atlanto-occiptal and atlanto-axial joints. The morphology of MDB was investigated by gross anatomic dissection and by histological observation utilizing both light microscopy and scanning electron microscopy. Additionally biomechanical tensile strength tests were conducted. Functionally, the CSFP was analyzed during passive head movements and electrical stimulation of the suboccipital muscles, respectively. The MDB was observed passing through both the dorsal atlanto-occipital and the atlanto-axial interspaces of the canine and consisted of collagenous fibers. The tensile strength of the collagenous fibers passing through the dorsal atlanto-occipital and atlanto-axial interspaces were 0.16 ± 0.04 MPa and 0.82 ± 0.57 MPa, respectively. Passive head movement, including lateral flexion, rotation, as well as flexion–extension, all significantly increased CSFP. Furthermore, the CSFP was significantly raised from 12.41 ± 4.58 to 13.45 ± 5.16 mmHg when the obliques capitis inferior (OCI) muscles of the examined specimens were electrically stimulated. This stimulatory effect was completely eliminated by severing the myodural bridge attachments to the OCI muscle. Head movements appeared to be an important factor affecting CSF pressure, with the MDB of the suboccipital muscles playing a key role this process. The present study provides direct evidence to support the hypothesis that the MDB may be a previously unappreciated significant power source (pump) for CSF circulation.

Existence and features of the myodural bridge in Gentoo penguins: A morphological study.

Recent studies have evidenced that the anatomical structure now known as the myodural bridge (MDB) connects the suboccipital musculature to the cervical spinal dura mater (SDM). In humans, the MDB passes through both the posterior atlanto-occipital and the posterior atlanto-axial interspaces. The existence of the MDB in various mammals, including flying birds (Rock pigeons and Gallus domesticus) has been previously validated. Gentoo penguins are marine birds, able to make 450 dives per day, reaching depths of up to 660 feet. While foraging, this penguin is able to reach speeds of up to 22 miles per hour. Gentoo penguins are also the world's fastest diving birds. The present study was therefore carried out to investigate the existence and characteristics of the MDB in Gentoo penguin (Pygoscelis papua), a non-flying, marine bird that can dive. For this study, six Gentoo penguin specimens were dissected to observe the existence and composition of their MDB. Histological staining was also performed to analyze the anatomic relationships and characteristic of the MDB in the Gentoo penguin. In this study, it was found that the suboccipital musculature in the Gentoo penguin consists of the rectus capitis dorsalis minor (RCDmi) muscle and rectus capitis dorsalis major (RCDma) muscle. Dense connective tissue fibers were observed connecting these two suboccipital muscles to the spinal dura mater (SDM). This dense connective tissue bridge consists of primarily type I collagen fibers. Thus, this penguin's MDB appears to be analogous to the MDB previously observed in humans. The present study evidences that the MDB not only exists in penguins but it also has unique features that distinguishes it from that of flying birds. Thus, this study advances the understanding of the morphological characteristics of the MDB in flightless, marine birds.

Variations in the cerebrospinal fluid dynamics of the American alligator (Alligator mississippiensis)

BackgroundStudies of mammalian CSF dynamics have been focused on three things: paravascular flow, pressure and pulsatility, and “bulk” flow; and three (respective) potential motive forces have been identified: vasomotor, cardiac, and ventilatory. There are unresolved questions in each area, and few links between the different areas. The American alligator (Alligator mississippiensis) has pronounced plasticity in its ventilatory and cardiovascular systems. This study was designed to test the hypothesis that the greater cardiovascular and ventilatory plasticity of A. mississippiensis would result in more variation within the CSF dynamics of this species.MethodsPressure transducers were surgically implanted into the cranial subarachnoid space of 12 sub-adult alligators; CSF pressure and pulsatility were monitored along with EKG and the exhalatory gases. In four of the alligators a second pressure transducer was implanted into the spinal subarachnoid space. In five of the alligators the CSF was labeled with artificial microspheres and Doppler ultrasonography used to quantify aspects of the spinal CSF flow.ResultsBoth temporal and frequency analyses of the CSF pulsations showed highly variable contributions of both the cardiac and ventilatory cycles. Unlike the mammalian condition, the CSF pressure pulsations in the alligator are often of long (~ 3 s) duration, and similar duration CSF unidirectional flow pulses were recorded along the spinal cord. Reduction of the duration of the CSF pulsations, as during tachycardia, can lead to a “summation” of the pulsations. There appears to be a minimum duration (~ 1 s) of isolated CSF pulsations. Simultaneous recordings of cranial and spinal CSF pressures reveal a 200 ms delay in the propagation of the pressure pulse from the cranium to the vertebral canal.ConclusionsMost of the CSF flow dynamics recorded from the alligators, are similar to what has been reported from studies of the human CSF. It is hypothesized that the link between ventilatory mechanics and CSF pulsations in the alligator is mediated by displacement of the spinal dura. The results of the study suggest that understanding the CSF dynamics of Alligator may provide unique insights into the evolutionary origins and functional regulation of the human CSF dynamics.

Microsurgical anatomy and treatment of dural defects in spontaneous spinal cerebrospinal fluid leaks.

Spontaneous spinal CSF leaks are caused by abnormalities of the spinal dura mater. Although most cases are treated conservatively or with an epidural blood patch, some intractable cases require neurosurgical treatment. However, previous reports are limited to a small number of cases. Preoperative detection and localization of spinal dural defects are difficult, and surgical repair of these defects is technically challenging. The authors present the anatomical characteristics of dural defects and surgical techniques in treating spontaneous CSF leaks. Among the consecutive patients who were diagnosed with spontaneous CSF leaks at the authors' institution between 2010 and 2020, those who required neurosurgical treatment were included in the study. All patients' clinical information, radiological studies, surgical notes, and outcomes were reviewed retrospectively. Outcomes of two different procedures in repairing dural defects were compared. Among 77 patients diagnosed with spontaneous CSF leaks, 21 patients (15 men; mean age 57 years) underwent neurosurgery. Dural defects were detected by FIESTA MRI in 7 patients, by CT myelography in 12, by digital subtraction myelography in 1, and by dynamic CT myelography in 1. The spinal levels of the defects were localized at the cervicothoracic junction in 16 patients (76%) and thoracolumbar junction in 4 (19%). Intraoperative findings revealed that the dural defects were small, circumscribed longitudinal slits located at the ventral aspect of the dura mater. The median dural defect size was 5 × 2 mm. The presence of dural defects at the thoracolumbar junction was associated with manifestation of an altered mental status, which was an unusual manifestation of CSF leaks (p = 0.003). Eight patients were treated via the posterior transdural approach with watertight primary sutures of the ventral defects, and 13 were treated with muscle or fat grafting. Regardless of the two different procedures, postoperative MRI showed either complete disappearance or significant reduction of the extradural CSF collection. No patient experienced postoperative neurological deficits. Clinical symptoms improved or stabilized in 20 patients with a median follow-up of 12 months. Dural defects in spontaneous CSF leaks were small, circumscribed longitudinal slits located ventral to the spinal cord at either the cervicothoracic or thoracolumbar junction. Muscle/fat grafting may be an alternative treatment to watertight primary sutures of ventral dural defects with a good outcome.

Anatomy of the posterolateral spinal epidural ligaments.

Background: The epidural ligaments (ELs) (of Hofmann) were described as fibrous bands interconnecting the ventrolateral spinal dura and the posterior longitudinal ligament below L1. They are hardly ever discussed in the literature or considered in hypothesis-driven basic science experiments or spine biomechanical models.Methods: Intraoperative photographs were obtained to illustrate a group of posterolateral spinal ELs. In addition, electronic database searches (PubMed, Ovid Embase, and SCOPUS) were utilized to summarize the anatomy, and relevant clinical and surgical factors impacting these ELs.Results: ELs attach circumferentially at most spinal levels. They anchor the nerve root sleeves ventrally, and therefore, may play a role in the some idiopathic neurologic deficits (e.g., postoperative radiculopathies, C5 palsies) in patients without radiological compression. The posterolateral ELs originate on the dura dorsal to the nerve root sleeves and insert on the ipsilateral lamina, interlaminar ligament, and facet capsule. They appear to be continuous with the peridural membrane, a fibrovascular sheath that surrounds the thecal sac and serves as a scaffold for the internal vertebral venous plexus of Batson and epidural fat.Conclusion: The spinal ELs should be divided sharply during surgery to prevent durotomies, especially in patients with advanced spondylosis and facet arthropathy. Disconnecting these ligaments releases the thecal sac laterally and ventrally, allowing for medial mobilization when performing discectomies or for working in the ventral epidural space.

Hypertrophic spinal pachymeningitis caused by ANCA-associated vasculitis revealed by 18F-FDG PET/CT

Rationale:Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) can involve the central nervous system in estimatedly 15% of patients. Hypertrophic pachymeningitis causes inflammatory hypertrophy of the cranial or spinal dura mater and patients present with various neurological deficits. ANCA-associated hypertrophic spinal pachymeningitis has rarely been reported in literature. We report a case of AAV presenting with hypertrophic spinal pachymeningitis detected by 18F-FDG PET/CT.Patient concerns:A 66-year-old woman diagnosed with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis developed back pain, bilateral lower limb weakness, dysuria, and dysporia 1 month ago.Diagnosis:Contrast-enhanced MRI showed thickening and enhancement of the dura mater in the thoracic cord. Intraspinal hypermetabolism in the corresponding region was observed on 18F-FDG PET/CT. The patient was finally diagnosed with ANCA-associated hypertrophic spinal pachymeningitis.Interventions:The patient was treated with a higher dose of prednisone and cyclophosphamide.Outcomes:After 2-week treatment, the patient's neurological symptoms improved rapidly and laboratory findings were ameliorated. A repeated contrast-enhanced MRI showed partial improvement of the disease in the thoracic cord.Lessons:18F-FDG PET/CT and contrast-enhanced MRI can aid in the clinical diagnosis and surveillance in AAV-associated hypertrophic spinal pachymeningitis and potentially facilitate early recognition and intervention to prevent irreversible neurological impairment.

Dura Mater: Anatomy and Clinical Implication

The dura mater is of similar embryological origin to the fascial organ. It contains several fibroblasts which make the dura mater a flexible structure. Dura mater is the outermost of the three layers of meninges, a thick and rigid inelastic membrane that covers the brain and spinal cord and that is impermeable to the cerebrospinal fluid. The cranial dura mater in certain respects differs anatomically from the dura material in the spinal cord, and it is important to classify them separately. This article reviews the anatomical structure of spinal and cranial dura mater and its anatomy with muscle, fascia, bone structure and ligaments. Dura mater is a structure in the body that is connected with systemic functions.

The biomechanical characteristics of spinal dura mater in the context of its basic morphology

Purpose: Spinal dura mater plays a crucial role in the biomechanics and protection of the spine. Therefore, the present study investigated the dura mater's mechanical and basic morphological properties to learn more about the biomechanical behaviour of this fibrous membrane. Methods: Tissue strips, oriented in the longitudinal and circumferential directions, were cut from the cervical, thoracic, and lumbar vertebrae parts of the porcine spinal cord. Uniaxial tensile tests were performed using a device with a speed of 4 mm/min until rupture of the sample. Results: It was demonstrated that the dura mater is a heterogeneous, anisotropic material. The longitudinal excised specimens showed the highest values of mechanical properties (ultimate force (FU), the stiffness coefficient (k), ultimate tensile strength (σUTS), and Young’s modulus (E)) compared to those of the circumferentially. Confocal microscopy and sulforhodamine B (SRB) assay enabled us to visualise collagen and elastin elements more efficiently without a need for sample fixation. Conclusions: The spinal dura mater mechanical properties are not uniform along the entire length of the spinal cord, but, in the case of morphological features, no major differences were noticed. The utilisation of SRB occurred to be a non-destructive, fast, and efficient tool for visualising even the smallest elastic fibres on different depths of examined samples. The mechanical and morphological properties of the dura mater provided by this study can be further used in computational modelling to understand injury mechanisms better and help develop injury prevention strategies.

Effects of anatomical sites on mechanical responses of spinal dura mater

Effects of anatomical sites on mechanical responses of spinal dura mater

Topography and evidence of a separate "fascia plate" for the femoral nerve inside the iliopsoas - A dorsal approach.

The femoral nerve stretch test is an essential part of clinical neurological examinations. This test is performed alongside Magnetic Resonance Imaging (MRI) to determine if there is any evidence of nerve root irritation, usually as a consequence of disc prolapse. The test occasionally gives false positive results. Why such false positives can occur, is subject to continued research, however, no obvious reason has yet emerged. We hypothesize that connectives of the femoral nerve may explain such a phenomenon. To see these connectives, we approached the femoral nerve from dorsal in 12 cases. With the use of ink injection into the subparaneural compartment of the femoral nerve and dissections, a thin transparent structure can clearly be seen that is separate from the epineurium, perineurium, and a paraneural sheath. A continuation of the paraneural sheath produces a fascia plate approximately 1.5 cm in width and with a thickness of around 3 mm, which not only circumnavigates the nerve but projects into the surrounding tissues. Our qualitative observations show that not only does this femoral nerve fascia plate exists, but it also contains nerves and vessels. Furthermore, we show that the femoral nerve is connected to the myofascial complex of the iliopsoas, and in a separate fascia plate from the iliopsoas fascia. This plate is a hitherto neglected connective which extends as far as the spinal dura mater. Evidence from our plastinates and histological sections suggests that when tension is applied to the femoral nerve during the femoral nerve stretch test, tension is also applied to the femoral nerve fascia plate. The femoral nerve fascia plate could be a specific factor that contributes to pain resulting in a false positive femoral nerve stretch test.