The "subdural" space: a new look at an outdated concept

Chemokines as markers of local inflammation and angiogenesis in patients with chronic subdural hematoma: a prospective study

OBJECTIVE

The goal of this study was to investigate the chemokines CCL2, CXCL8, CXCL9 and CXCL10 as markers of the inflammatory responses in chronic subdural hematoma (CSDH).

METHODS

Samples of peripheral venous blood and CSDH fluid (obtained during surgery) in 76 adult patients were prospectively analyzed. Chemokine values were assessed by a Multiplex antibody bead kit.

RESULTS

We found significantly higher levels of chemokines CCL2, CXCL8, CXCL9 and CXCL10 in hematoma fluid compared with serum.

CONCLUSIONS

Chemokines are elevated in the hematoma cavity of patients with CSDH. It is likely that these signaling modulators play an important role in promoting local inflammation. Furthermore, biological activity of CCL2 and CXCL8 may promote neovascularization within the outer CSDH membrane, and a compensatory angiostatic activity of CXCL9 and CXCL10 may contribute to repairing this disorder. This phenomenon was restricted to the hematoma site, and the systemic chemokine levels might not reflect local immune responses.

Acute-on-Chronic Subdural Hematoma: Not Uncommon Events

OBJECTIVE

Patients with asymptomatic chronic subdural hematoma (SDH) are prone to fall or slip. Acute trauma on these patients may develop acute subdural bleeding over the chronic SDH. We recently experienced 9 patients with acute-on-chronic SDH. We report the clinical and radiological features of this lesion.

METHODS

We retrospectively examined the computed tomographic (CT) scans of 107 consecutive patients who diagnosed as chronic SDH from January 2008 to December 2010. All cases of CSDH were diagnosed on CT with or without MRI scan.

RESULTS

Acute-on-chronic SDH is not rare, being 8% of chronic SDH. The most common cause of trauma was a slip in drunken state. Alcoholism with multiple episodes of trauma was one of the prominent histories. Acute-on-chronic SDH appeared as a hyperdense layer of clot with irregular blurred margin or lumps in liquefied hematoma. Single or two burr holes was usually effective to remove the hematoma.

CONCLUSION

Repeated trauma may cause acute bleeding over the chronic SDH. It will be helpful to understand the role of repeated trauma as a mechanism of hematoma enlargement.

Spinal subdural hemorrhage in abusive head trauma: a retrospective study

PURPOSE

To compare the relative incidence, distribution, and radiologic characteristics of spinal subdural hemorrhage after abusive head trauma versus that after accidental trauma in children.

MATERIALS AND METHODS

This study received prior approval from the Human Subjects Protection Office. Informed consent was waived. This study was HIPAA compliant. Two hundred fifty-two children aged 0-2 years treated for abusive head trauma at our institute between 1997 and 2009 were identified through retrospective chart review. A second group of 70 children aged 0-2 years treated at our institute for well-documented accidental trauma between 2003 and 2010 were also identified through retrospective chart review. All clinical data and cross-sectional imaging results, including computed tomographic and magnetic resonance imaging of the brain, spine, chest, abdomen, and pelvis, were reviewed for both of these groups. A Fisher exact test was performed to assess the statistical significance of the proportion of the spinal canal subdural hemorrhage in abusive head trauma versus that in accidental trauma.

RESULTS

In the abusive head trauma cohort, 67 (26.5%) of 252 children had evaluable spinal imaging results. Of these, 38 (56%) of 67 children had undergone thoracolumbar imaging, and 24 (63%) of 38 had thoracolumbar subdural hemorrhage. Spinal imaging was performed in this cohort 0.3-141 hours after injury (mean, 23 hours ± 27 [standard deviation]), with 65 (97%) of 67 cases having undergone imaging within 52 hours of injury. In the second cohort with accidental injury, only one (1%) of 70 children had spinal subdural hemorrhage at presentation; this patient had displaced occipital fracture. The comparison of incidences of spinal subdural hemorrhage in abusive head trauma versus those in accidental trauma was statistically significant (P < .001).

CONCLUSION

Spinal canal subdural hemorrhage was present in more than 60% of children with abusive head trauma who underwent thoracolumbar imaging in this series but was rare in those with accidental trauma.

The "Shaken Baby" syndrome: pathology and mechanisms

The "Shaken Baby" syndrome (SBS) is the subject of intense controversy; the diagnosis has in the past depended on the triad of subdural haemorrhage (SDH), retinal haemorrhage and encephalopathy. While there is no doubt that infants do suffer abusive injury at the hands of their carers and that impact can cause catastrophic intracranial damage, research has repeatedly undermined the hypothesis that shaking per se can cause this triad. The term non-accidental head injury has therefore been widely adopted. This review will focus on the pathology and mechanisms of the three physiologically associated findings which constitute the "triad" and are seen in infants suffering from a wide range of non-traumatic as well as traumatic conditions. "Sub" dural bleeding in fact originates within the deep layers of the dura. The potential sources of SDH include: the bridging veins, small vessels within the dura itself, a granulating haemorrhagic membrane and ruptured intracranial aneurysm. Most neuropathologists do not routinely examine eyes, but the significance of this second arm of the triad in the diagnosis of Shaken Baby syndrome is such that it merits consideration in the context of this review. While retinal haemorrhage can be seen clinically, dural and subarachnoid optic nerve sheath haemorrhage is usually seen exclusively by the pathologist and only rarely described by the neuroradiologist. The term encephalopathy is used loosely in the context of SBS. It may encompass anything from vomiting, irritability, feeding difficulties or floppiness to seizures, apnoea and fulminant brain swelling. The spectrum of brain pathology associated with retinal and subdural bleeding from a variety of causes is described. The most important cerebral pathology is swelling and hypoxic-ischaemic injury. Mechanical shearing injury is rare and contusions, the hallmark of adult traumatic brain damage, are vanishingly rare in infants under 1 year of age. Clefts and haemorrhages in the immediate subcortical white matter have been assumed to be due to trauma but factors specific to this age group offer other explanations. Finally, examples of the most common causes of the triad encountered in clinical diagnostic and forensic practice are briefly annotated.

The surgical management of chronic subdural hematoma

Chronic subdural hematoma (cSDH) is an increasingly common neurological disease process. Despite the wide prevalence of cSDH, there remains a lack of consensus regarding numerous aspects of its clinical management. We provide an overview of the epidemiology and pathophysiology of cSDH and discuss several controversial management issues, including the timing of post-operative resumption of anticoagulant medications, the effectiveness of anti-epileptic prophylaxis, protocols for mobilization following evacuation of cSDH, as well as the comparative effectiveness of the various techniques of surgical evacuation. A PubMed search was carried out through October 19, 2010 using the following keywords: "subdural hematoma", "craniotomy", "burr-hole", "management", "anticoagulation", "seizure prophylaxis", "antiplatelet", "mobilization", and "surgical evacuation", alone and in combination. Relevant articles were identified and back-referenced to yield additional papers. A meta-analysis was then performed comparing the efficacy and complications associated with the various methods of cSDH evacuation. There is general agreement that significant coagulopathy should be reversed expeditiously in patients presenting with cSDH. Although protocols for gradual resumption of anti-coagulation for prophylaxis of venous thrombosis may be derived from guidelines for other neurosurgical procedures, further prospective study is necessary to determine the optimal time to restart full-dose anti-coagulation in the setting of recently drained cSDH. There is also conflicting evidence to support seizure prophylaxis in patients with cSDH, although the existing literature supports prophylaxis in patients who are at a higher risk for seizures. The published data regarding surgical technique for cSDH supports primary twist drill craniostomy (TDC) drainage at the bedside for patients who are high-risk surgical candidates with non-septated cSDH and craniotomy as a first-line evacuation technique for cSDH with significant membranes. Larger prospective studies addressing these aspects of cSDH management are necessary to establish definitive recommendations.

Ventral “Spinal Epidural Meningeal Cysts”—Not Epidural and Not Cysts? Case Series and Review of the Literature

BACKGROUND:

Ventral spinal epidural meningeal cysts are rare entities for which the pathogenesis is poorly understood.

OBJECTIVE:

We present the clinical, radiographic, surgical, and pathologic findings of 4 patients with extensive ventral spinal epidural meningeal cysts and review the relevant literature. In addition, we discuss a suspected mechanism for pathogenesis.

METHODS:

Four patients with anterior spinal epidural meningeal cysts are retrospectively reviewed.

RESULTS:

Ventral spinal epidural meningeal cysts are often large, extending on average from C2 to L1 in our series. Patients typically present with a prolonged course of symptoms and signs, including segmental muscle weakness and atrophy, subtle myelopathy, mild to moderate spinal pain, and headache. Histopathologic analysis of the cyst wall demonstrates collagenous tissue consistent with dura but without arachnoid features. Dynamic computed tomographic myelography is the study of choice for localization of the primary dural defect. Patient symptoms and neurological deficits routinely improve after appropriate surgical intervention.

CONCLUSION:

Diverse signs and symptoms herald the presentation of ventral spinal meningoceles. Intraoperative, radiographic, and pathological findings are all suggestive of an intradural dissection as the etiology. Hence, they may be more appropriately named “ventral spinal intradural dissecting meningoceles.” Definitive treatment involves identification and obliteration of the dural defect.

Risk factors associated with subdural hygroma after decompressive craniectomy in patients with traumatic brain injury : a comparative study

OBJECTIVE

Subdural hygroma (SDG) is a complication occurring after head trauma that may occur secondary to decompressive craniectomy (DC). However, the mechanism underlying SDG formation is not fully understood. Also, the relationship between the operative technique of DC or the decompressive effect and the occurrence and pathophysiology of SDG has not been clarified. Purpose of this study was to investigate the risk factors of SDG after DC in our series.

METHODS

From January 2004 to December 2008, DC was performed in 85 patients who suffered from traumatic brain injury. We retrospectively reviewed the clinical and radiological features. For comparative analysis, we divided the patients into 2 groups : one group with SDG after craniectomy (19 patients; 28.4% of the total sample), the other group without SDG (48 patients; 71.6%). The risk factors for developing SDG were then analyzed.

RESULTS

The mean Glasgow Outcome Scale (GOS) scores at discharge of the groups with and without SDG were 2.8 and 3.1, respectively (p<0.0001). Analysis of radiological factors showed that a midline shift in excess of 5 mm on CT scans was present in 19 patients (100%) in the group with SDG and in 32 patients (66.7%) in the group without SDG (p<0.05). An accompanying subarachnoid hemorrhage (SAH) was seen in 17 patients (89.5%) in the group with SDG and in 29 patients (60.4%) in the group without SDG (p<0.05). Delayed hydrocephalus accompanied these findings in 10 patients (52.6%) in the group with SDG, versus 5 patients (10.4%) in the group without SDG (p<0.05). On CT, compression of basal cisterns was observed in 14 members (73.7%) in the group with SDG and in 18 members of the group without SDG (37.5%) (p<0.007). Furthermore, tearing of the arachnoid membrane, as observed on CT, was more common in all patients in the group with SDG (100%) than in the group without SDG (31 patients; 64.6%) (p<0.05).

CONCLUSION

GOS showed statistically significant difference in the clinical risk factors for SDG between the group with SDG and the group without SDG. Analysis of radiological factors indicated that a midline shifting exceeding 5 mm, SAH, delayed hydrocephalus, compression of basal cisterns, and tearing of the arachnoid membrane were significantly more common in patients with SDG.

Normal pressure subdural hygroma with mass effect as a complication of decompressive craniectomy

BACKGROUND

Subdural posttraumatic collections are called usually Traumatic Subdural Hygroma (TSH). TSH is an accumulation of cerebrospinal fluid (CSF) in the subdural space after head injury. These collections have also been called Traumatic Subdural Effusion (TSE) or External Hydrocephalous (EHP) according to liquid composition, or image features. There is no agreement about the pathogenesis of these entities, how to define them or if they are even different phenomena at all.

CASE DESCRIPTION

We present a case of a complex posttraumatic subdural collection, the role of cranioplasty as definite solution and review the literature related to this complication.

CONCLUSION

Patients who undergo decompressive craniectomy (DC) have a risk of suffering a subdural collection of 21-50%. Few of these collections will become symptomatic and will need evacuation. When this happens, cranioplasty might be the definitive solution.

Acute Spinal Epidural Hematoma and Cranial Interdural Hematoma Due to a Rupture of a Posterior Communicating Artery Aneurysm: Case Report

BACKGROUND AND IMPORTANCE:

We describe an unusual presentation of a ruptured aneurysm of the posterior communicating artery with an acute intracranial hematoma between the dural layers associated with an acute spinal epidural hematoma descending to L1.

CLINICAL PRESENTATION:

A 35-year-old woman presented 3 hours after ictus with a postcoital headache, neck stiffness, and bilateral abducens cranial nerve palsy. No other neurological deficits were present. Clinically, she had a subarachnoid hemorrhage World Federation of Neurosurgical Societies grade 1. CT scan demonstrates an acute subdural hematoma, extending from the right parasellar region, around the clivus, tentorium, and falx. Angio-CT showed a posterior communicating artery aneurysm and an anterior communicating artery aneurysm and an extension of the hematoma to the cervical spine. This justified a spinal and cerebral MRI that confirmed an extension of the hematoma to the epidural space at the cervical, thoracic, and lumbar levels. Three-dimensional digital subtraction angiography confirmed aneurysms on the right posterior communicating artery and on the anterior communicating artery. Both aneurysms were completely occluded by coiling. With reference to the concept of the cranial subdural compartment described in studies conducted using an electron microscope, this group of hematomas was classified as interdural.

CONCLUSION:

Ruptured aneurysm of the posterior communicating artery may cause cranial acute interdural hematoma with a typical subarachnoid hemorrhage clinical presentation, and it rarely can extend to spinal epidural space.

Spinal cerebrospinal fluid volume in healthy elderly individuals

The amount of spinal cerebrospinal fluid (CSF) could be of importance for the understanding of CSF dynamics, CSF biomarker analyses as well as for the amount and effect of anaesthesia using intrathecally administered drugs. However, knowledge of spinal CSF volumes is scarce. The main purpose of this article is to present data on spinal CSF volumes. In total, 22 healthy individuals aged between 64 and 76 years underwent MR imaging with a 3D balanced turbo field echo pulse sequence, which provided high contrast between spinal cord, CSF and the extradural surroundings. The entire spinal CSF volume, the cervical, thoracic, and lumbosacral CSF volumes and the spinal cord volume were calculated. The total spinal CSF volume was 81 ± 13 ml (range 52-103 ml). The amount of CSF in the cervical region was 19 ± 4 ml, in the thoracic region 38 ± 8 and in the lumbosacral region 25 ± 7 ml. There was no difference between genders nor was there any correlation with height. The volume of the spinal cord was 20 ± 3 ml. The results present new magnetic resonance imaging-based data on the spinal CSF volume in healthy elderly individuals.

Lumbar Subdural Hematoma From Intracranial Subarachnoid Hemorrhage Presenting With Bilateral Foot Drop: Case Report

BACKGROUND AND IMPORTANCE:

We report a patient with lumbar subdural hematoma secondary to intracranial subarachnoid hemorrhage (SAH) presenting with bilateral foot drop and describe our management.

CLINICAL PRESENTATION:

A 37-year-old woman presented with grade 4 SAH and hydrocephalus requiring emergent external ventricular drainage. Angiography demonstrated a left vertebral artery dissection and pseudoaneurysm that was treated with embolization of the vertebral artery. Six days after admission, her neurologic examination significantly improved. She was awake, alert, following commands, and moving all her extremities normally except for bilateral foot drop. An MRI scan revealed a lumbar subdural hematoma with severe thecal sac compression at L4-S1. The patient was initially treated with expectant management followed by surgery after she demonstrated only modest improvement. Evacuation of the hematoma was undertaken by an L5-S1 laminectomy and drainage of the liquefied clot in the subdural, extra-arachnoid space. Postoperatively, the patient demonstrated improved strength in all muscle groups except for left lower extremity eversion.

CONCLUSION:

We present a case of subdural hematoma that caused bilateral foot drop. Neurologic improvement occured after evacuation of the hematoma.

A rare, high cervical traumatic spinal subdural hematoma

Spinal subdural hematomas (SSDH) are rare lesions occurring in association with a wide variety of conditions, including anticoagulation, coagulation disorders, spinal anesthesia, lumbar puncture, spinal tumors and vascular malformations. SSDH resulting from trauma are the exception. We present a 62-year-old woman with a rare post-traumatic focal SSDH at C1 with bulbomedullary compression, treated successfully with surgery. A review of the literature revealed 26 patients with traumatic SSDH. The aim of this report is to describe the clinical presentation, imaging characteristics and management of traumatic SSDH. The controversial pathogenesis is also discussed.

Imaging of nonaccidental injury and the mimics: issues and controversies in the era of evidence-based medicine

Because of the controversy involving the determination of child abuse, or nonaccidental injury (NAI), radiologists must be familiar with the issues, literature, and principles of evidence-based medicine to understand the role of imaging. Children with suspected NAI must receive protective evaluation along with a timely and complete clinical and imaging work-up. Imaging findings cannot stand alone and must be correlated with clinical findings, laboratory testing, and pathologic and forensic examinations. Only the child protection investigation may provide the basis for inflicted injury in the context of supportive clinical, imaging, biomechanical, or pathology findings.

The interperiosteo-dural concept applied to the perisellar compartment: a microanatomical and electron microscopic study

Object

The dura mater has 2 dural layers: the endosteal layer (outer layer), which is firmly attached to the bone, and the meningeal layer (inner layer), which directly covers the brain. These 2 dural layers join together in the middle temporal fossa or the convexity and separate into the orbital, lateral sellar compartment (LSC), or spinal epidural space to form the extradural neural axis compartment (EDNAC). The aim of this work was to anatomically verify the concept of the EDNAC by using electron microscopy.

Methods

The authors studied the cadaveric heads obtained from 13 adults. Ten of the specimens (or 20 perisellar areas) were injected with colored latex and fixed in formalin. They carefully removed each brain to allow a superior approach to the perisellar area. The 3 other specimens were studied by microscopic and ultrastructural methods to describe the EDNAC in the perisellar area. Special attention was paid to the dural layers surrounding the perisellar area. The authors studied the anatomy of the meningeal architecture of the LSC, the petroclival venous confluence, the orbit, and the trigeminal cave. After dissection, the authors took photographs of the dural layers with the aid of optical magnification. The 3 remaining heads, obtained from fresh cadavers, were prepared for electron microscopic study.

Results

The EDNAC is limited by the endosteal layer and the meningeal layer and contains fat and/or venous blood. The endosteal layer and meningeal layer were not identical on electron microscopy; this finding can be readily related to the histology of the meninges.

Conclusions

In this study, the authors demonstrated the existence of the EDNAC concept in the perisellar area by using dissected cadaveric heads and verified the reality of the concept of the meningeal layer with electron microscopy. These findings clearly demonstrated the existence of the EDNAC, a notion that has generally been accepted but never demonstrated microscopically.

Interdural haemorrhage of the posterior fossa due to infraclinoidal carotid artery aneurysm rupture

Several anatomical studies indicate that the intracranial pachimeninges consist of two dural layers joined together, which divide while bordering the venous sinuses, therefore located in an interdural space. We present here an uncommon case of haematoma due to rupture of an infraclinoidal internal carotid artery aneurysm. The dome of the aneurysm leaned against the posterior wall of the cavernous sinus and, following laceration, pierced the inner dural layer and caused its detachment from the periosteal layer, thus determining a truly interdural haematoma which progressively involved the whole posterior fossa. A 42-year-old female was admitted to our institution with a recent history of thunderclap headache and right ophthalmoparesis. Two cerebral computerised scan tomographies performed elsewhere tested negative for subarachnoid haemorrhage. A cerebral magnetic resonance imaging (MRI) showed a thin collection of blood adjacent to the clivus and all along the wall of the posterior fossa and foramen magnum. A right infraclinoid internal carotid artery aneurysm was also diagnosed, subsequently better highlighted on angiography. The patient underwent surgery with aneurysm clipping. Post-operative course was uneventful, and control angiography showed complete exclusion of the aneurysm from blood circulation. The patient was discharged 5 days later. At 3 months follow-up ophthalmoplegia had disappeared, and the patient had fully recovered. The possibility of a truly interdural location, particularly in cases of non-traumatic parasellar or clival haematomas, must be included in the differential diagnosis of posterior fossa extra-axial haemorrhages. MRI is the test of choice for diagnostic purposes.

Extensive scarring induced by chronic intrathecal tubing augmented cord tissue damage and worsened functional recovery after rat spinal cord injury

Intrathecal infusion has been widely used to directly deliver drugs or neurotrophins to a lesion site following spinal cord injury. Evidence shows that intrathecal infusion is efficient for 7 days but is markedly reduced after 14 days, due to time dependent occlusion. In addition, extensive fibrotic scarring is commonly observed with intrathecal infusion. These anomalies need to be clearly elucidated in histology. In the present study, all adult Long-Evans rats received a 25 mm contusion injury on spinal cord T10 produced using the NYU impactor device. Immediately after injury, catheter tubing with an outer diameter of 0.38 mm was inserted through a small dural opening at L3 into the subdural space with the tubing tip positioned near the injury site. The tubing was connected to an Alzet mini pump, which was filled with saline solution and was placed subcutaneously. Injured rats without tubing served as control. Rats were behaviorally tested for 6 weeks using the BBB locomotor rating scale and histologically assessed for tissue scarring. Six weeks later, we found that the intrathecal tubing caused extensive scarring and inflammation, related to neutrophils, macrophages and plasma cells. The tubing's tip was occluded by scar tissue and inflammatory cells. The scar tissue surrounding the tubing consists of 20-70 layers of fibroblasts and densely compacted collagen fibers, seriously compressing and damaging the cord tissue. BBB scores of rats with intrathecal tubing were significantly lower than control rats (p<0.01) from 2 weeks after injury, implying serious impairment of functional recovery caused by the scarring.

Imaging of the meninges and the extra-axial spaces

The separate meningeal layers and extraaxial spaces are complex and can only be differentiated by pathologic processes on imaging. Differentiation of the location of such processes can be achieved using different imaging modalities. In this pictorial review we address the imaging techniques, enhancement and location patterns, and disease spread that will promote accurate localization of the pathology, thus improving accuracy of diagnosis. Typical and unusual magnetic resonance (MR), computed tomography (CT), and ultrasound imaging findings of many conditions affecting these layers and spaces are described.

Cranial subdural haematoma with concomitant spinal epidural and spinal subarachnoid haematomas: a case report

A 76-year-old man presented with a 4-day history of bilateral leg pain. Magnetic resonance imaging (MRI) of the lumbosacral spine revealed a spinal subarachnoid and spinal epidural haematomas. MRI of the brain revealed a chronic intracranial subdural haematoma with a midline shift. On further questioning, the patient reported a history of a fall 6 weeks earlier and had no evidence of coagulopathy. He underwent a burr-hole decompression of the intracranial subdural haematoma. At the one-year follow-up, the patient was symptom free with no leg pain or headache. The concomitant occurrence of an intracranial subdural haematoma with spinal epidural and spinal subarachnoid haematomas is rare. MRI of the brain and the entire spine is essential in the presence of a spontaneous spinal haematoma.

Influence of cranial morphology on the location of chronic subdural haematoma

BACKGROUND

The purpose of the present study was to evaluate the relationship between cranial morphology and location of a chronic subdural haematoma (CSDH) in patients with and without intracranial vault asymmetry.

METHOD

The study was conducted in 110 consecutive adult patients who underwent surgery for CSDH. The relationship between the following variables and CSDH was studied: sex, age, past medical history, history of trauma, interval between head injury and symptoms, clinical presentation, location of the CSDH, symmetry of the frontal and occipital intracranial vault on the CT scan and/or MR images, surgical treatment and outcome. Throughout the analysis, p < 0.05 was considered statistically significant.

FINDINGS

The frontal cranial vault was symmetrical in 48 patients (43.6%) and asymmetrical in 62 patients (56.4%). CSDH was more commonly bilateral in patients with a symmetrical frontal cranial vault than those with an asymmetrical shape (41.7% vs 17.7% and this difference is statistically significant (p = 0.01). In 62 patients with an asymmetric frontal skull vault, the CSDH was bilateral in 11 patients. In the remaining 51 patients, the CSDH was located on the same side of the most curved frontal convexity in 34 patients and on the side of the less curved frontal convexity in 17 patients. The occipital cranial vault was symmetrical in 44 patients (40%) and asymmetrical in 66 patients (60%). CSDH was more commonly bilateral in patients with a symmetrical occipital cranial vault than those with an asymmetrical one (40.9% vs 19.7%) and this difference was also statistically significant (p = 0.019). In 66 patients with an asymmetric occipital skull vault, the CSDH was bilateral in 13 patients. In the remaining 53 patients, the CSDH located on the same side of the most curved occipital convexity in 39 patients and on the side of the less curved occipital convexity in 14 patients.

CONCLUSIONS

Frontal and occipital intracranial vault morphology provides valuable information about location of CSDH. Bilateral CSDH is common in patients with symmetrical frontal and occipital cranial vault. In asymmetrical cranium, CSDH usually locates on the same side of the most curved frontal or occipital convexity. Identification of this relationship can be very useful to elucidate the origin and the pathogenesis of CSDH.

Demonstration of fluid channels in human dura and their relationship to age and intradural bleeding

PURPOSE

This paper aims to make a systematic study of human dura to establish the presence of fluid transport channels and their relationship to age.

METHODS

Samples of parasagittal dura from autopsy cases from mid-gestation to the ninth decade were examined by light microscopy.

RESULTS

We have demonstrated the presence of unlined rounded spaces, uncommon in the fetus and neonate but increasingly evident after 30 weeks of postnatal life. We have shown that intradural bleeding is inversely correlated with the presence of these channels and with age.

CONCLUSIONS

We suggest that dural maturation, involving the development of arachnoid granulations, may be related to dilatation of intradural fluid channels, allowing them to be identified histologically. The risk of reflux of blood into the dura appears to reduce with age.

Dural relationships of Meckel cave and lateral wall of the cavernous sinus

OBJECT

The purpose of this study was to elucidate the anatomy of the trigeminal nerve (cranial nerve [CN] V), Meckel cave (MC), and lateral wall of the cavernous sinus (CS).

METHODS

Ten fresh cadaver heads (20 sides) and 2 middle fossa embalmed specimens were removed, decalcified, sectioned, stained, and studied microscopically.

RESULTS

In the MC, the posterior fossa meningeal dura extended into the middle fossa surrounding CN V. The average medial length of the MC was 16.7 mm and the lateral length was 13.5 mm. The dural roof of MC was thicker than its floor and was covered by a paw-shaped fibrous tissue extending from the tentorium to the ganglion (in 100% of specimens). Between the dural sleeve of the MC and venous space of the CS, a separate fibrous wall could be identified in 45% (9 of 20) extending between the tentorium and the floor of the CS. The mean length of CN V in the MC proximal to the posterior margin of the Gasserian ganglion was 11.8 mm. The mean length of CN V1 was 19.4 mm; V2, 12.3 mm; and V3, 7.4 mm distal to the anterior margin of the ganglion. The periosteal dura followed the bone of the middle fossa and was continuous with the extracranial periosteum. The lateral dural wall of the CS consisted of a medial (membranous) and a lateral wall. The latter was separated into a thin outer layer and a thicker fibrous inner layer that became thinner as it extended posterolaterally.

CONCLUSIONS

The MC is an extension of the posterior fossa dura with intricate relationships with the surrounding dural layers.

Relationship between supratentorial arachnoid cyst and chronic subdural hematoma: neuroradiological evidence and surgical treatment

Object

Arachnoid cysts are relatively common congenital intracranial mass lesions that arise during the development of the meninges. They can be complicated by the formation of an ipsilateral chronic subdural hematoma (CSDH) after minor cranial trauma. Treatment of these coexisting conditions remains controversial. In this study the authors describe the anatomical, clinical, and neuroradiological features and outcome in a series of patients whose CSDH associated with arachnoid cysts were managed surgically by draining the hematoma alone and leaving the cyst intact. The authors based this surgical management on histological and neuroradiological observations concerning these associated medical conditions.

Methods

A series of 8 patients with CSDHs associated with arachnoid cysts underwent surgery to drain the hematoma though a bur hole. The arachnoid cyst was left intact. Postoperative follow-up included CT scanning and T1- and T2-weighted MR imaging.

Results

Clinical, anatomical, and radiological observations suggest that because separate membranes cover arachnoid cysts and the related hematoma, arachnoid cysts remain unaffected by the subdural bleeding. In the present study, these observations received support from the neuroimaging appearances, suggesting that arachnoid cysts related to hematoma contained only blood breakdown products from the hematoma that had filtered through the reciprocal dividing membranes.

Conclusions

Arachnoid cysts associated with SDH are anatomically separate conditions whose neurological symptoms respond to surgical drainage of the CSDH alone.

Dynamics of subdural hygroma following decompressive craniectomy: a comparative study

Object

This retrospective comparative cohort study was aimed at discovering the risk factors associated with subdural hygroma (SDG) following decompressive craniectomy (DC) to relieve intracranial hypertension in severe head injury.

Methods

Sixty-eight of 104 patients who had undergone DC during a 48-month period and survived > 30 days were eligible for this study. To assess the dynamics of subdural fluid collections, the authors compared CT scanning data from and the characteristics of 39 patients who had SDGs with the data in 29 patients who did not have hygromas. Variables significant in the appearance, evolution, and resolution of this complication were analyzed in a 36-week longitudinal study.

Results

The earliest imaging evidence of SDG was seen during the 1st week after DC. The SDG volume peaked between Weeks 3 and 4 post-DC and was gradually resolved by the 17th week. Among the mechanisms of injury, motor vehicle accidents were most often linked to the development of an SDG after DC (p < 0.0007), and falls were least often associated (p < 0.005). Moreover, patients with diffuse brain injury were more prone to this complication (p < 0.0299) than those with an evacuated mass (p < 0.0001). There were no statistically significant differences between patients with and without hygromas in terms of age, sex, Glasgow Coma Scale score, intraventricular and subarachnoid hemorrhage, levels of intracranial pressure and cerebral perfusion pressure, timing of decompression, and the need for CSF diversion. More than 90% of the SDGs were ipsilateral to the side of the craniectomy, and 3 (8%) of 39 SDGs showed evidence of internal bleeding at ~ 8 weeks postinjury. Surgical evacuation was needed in 4 patients with SDGs.

Conclusions

High dynamic accidents and patients with diffuse injury were more prone to SDGs. Close to 8% of SDGs converted themselves into subdural hematomas at ~ 2 months postinjury. Although SDGs developed in 39 (~ 60%) of 68 post-DC patients, surgical evacuation was needed in only 4.

Evidence of occurrence of intradural and subdural hemorrhage in the perinatal and neonatal period in the context of hypoxic Ischemic encephalopathy: an observational study from two referral institutions in the United Kingdom

The occurrence of subdural hemorrhage (SDH) on the convexities of the cerebral hemispheres is not an unusual finding in the setting of intrauterine, perinatal, or neonatal deaths, the hemorrhage usually presenting either as a thin film over the occipital poles or as a small infratentorial bleed. Working in 2 referral centers with over 30,000 deliveries per year, we routinely examine the dura macroscopically and histologically in nonmacerated fetuses over 24 weeks in gestation and in neonates. This paper describes our experience of intradural hemorrhage (IDH) and SDH associated with hypoxia. Our series comprises 25 fetuses and 30 neonates with obvious macroscopic intradural hemorrhage and hypoxia of varying degrees of severity diagnosed by systematic examination of the brain. Fetal gestational age ranged from 26-41/40 weeks (all no more than 24 hours from intrauterine death), while the 30 neonates lived for between 1 hour and 19 days. Simultaneously with IDH, frank SDH was seen in 2 of 3 of all cases (16 fetuses and 20 neonates). Intradural hemorrhage was more prominent in the posterior falx and tentorium, most likely because of the existence of 2 venous plexus at these sites. Our findings demonstrate that SDH and cerebral hypoxia are common associations of IDH and that SDH (often seen as a thin film ofhemorrhage) almost always occurs in association with diffuse falcine IDH. Diffuse IDH with SDH are more frequently associated with severe or moderate hypoxic ischemic encephalopathy (HIE), while mild or early HIE is more common with focal IDH without SDH.

Anatomy and development of the meninges: implications for subdural collections and CSF circulation

The dura is traditionally viewed as a supportive fibrous covering of the brain containing the dural venous sinuses but otherwise devoid of vessels and lacking any specific function. However, review of the embryology and anatomy reveals the dura to be a complex, vascularized and innervated structure, not a simple fibrous covering. The dura contains an inner vascular plexus that is larger in the infant than in the adult, and this plexus likely plays a role in CSF absorption. This role could be particularly important in the infant whose arachnoid granulations are not completely developed. Although subdural hemorrhage is frequently traumatic, there are nontraumatic conditions associated with subdural hemorrhage, and the inner dural plexus is a likely source of bleeding in these nontraumatic circumstances. This review outlines the development and age-specific vascularity of the dura and offers an alternative perspective on the role of the dura in homeostasis of the central nervous system.

Inflicted traumatic brain injury in infants and young children

This article will discuss the subject of inflicted or abusive head injury in infants and young children. Inflicted neurotrauma is a very common injury and a frequent problem in attempting to distinguish between inflicted and accidental injury. Inflicted head injury occurs usually in the home in the presence of the individual who has inflicted the injury outside the view of unbiased witnesses. Distinguishing between inflicted and accidental injury may be dependent upon the pathological findings and consideration of the circumstances surrounding the injury. The most common finding in an inflicted head injury is the presence of subdural hemorrhage. Subdural hemorrhage may occur in a variety of distributions and appearances. The natural history of subdural bleeding and the anatomy of the "subdural" will be considered. The anatomy of the dura and its attachment to the skull and to the arachnoid determines how subdural bleeding evolves into the cleaved dural border cell layer and as well as how bridging veins are torn and anatomically where bleeding will occur. Different biomechanical mechanisms result in different distributions of subdural blood and these differences will be discussed.

Diffuse pachymeningeal hyperintensity and subdural effusion/hematoma detected by fluid-attenuated inversion recovery MR imaging in patients with spontaneous intracranial hypotension

BACKGROUND AND PURPOSE

Fluid-attenuated inversion recovery (FLAIR) MR imaging has advantages to detect meningeal lesions. FLAIR MR imaging was used to detect pachymeningeal thickening and thin bilateral subdural effusion/hematomas in patients with spontaneous intracranial hypotension (SIH).

MATERIALS AND METHODS

Eight patients were treated under clinical diagnoses of SIH. Chronologic MR imaging studies, including the FLAIR sequence, were retrospectively reviewed.

RESULTS

Initial MR imaging showed diffuse pachymeningeal thickening as isointense in 6 cases, hypoisointense in 1 case, and isohyperintense in 1 case on the T1-weighted MR images, and hyperintense in all cases on both T2-weighted and FLAIR MR images. Dural (pachymeningeal) hyperintensity on FLAIR MR imaging had the highest contrast to CSF, and was observed as linear in all patients, usually located in the supratentorial convexity and also parallel to the falx, the dura of the posterior fossa convexity, and the tentorium, and improved after treatment. These characteristics of diffuse pachymeningeal hyperintensity on FLAIR MR imaging were similar to diffuse pachymeningeal enhancement (DPME) on T1-weighted imaging with gadolinium. Initial FLAIR imaging clearly showed subdural effusion/hematomas in 6 of 8 patients. The thickness of subdural effusion/hematomas sometimes increased transiently after successful treatment and resolution of clinical symptoms.

CONCLUSION

Diffuse pachymeningeal hyperintensity on FLAIR MR imaging is a similar sign to DPME for the diagnosis of SIH but does not require injection of contrast medium. FLAIR is useful sequence for the detection of subdural effusion/hematomas in patients with SIH.

Medial Sphenoid Ridge Meningiomas: Classification, Microsurgical Anatomy, Operative Nuances, and Long-Term Surgical Outcome in 35 Consecutive Patients

Objective:

On the basis of contemporary multiplanar imaging, microsurgical observations, and long-term follow-up in 60 consecutive patients with sphenoid ridge meningiomas, we propose a modification to Cushing's classification of these tumors. This article will concentrate on patients from this series with global medial sphenoid ridge tumors.

Methods:

Data were collected prospectively for 35 patients with global meningiomas arising from the medial portion of the sphenoid ridge that were surgically treated between 1982 and 2002.

Results:

All patients were followed for the entire length of this study (mean, 12.8 yr). The tumor size ranged from 2 to 8 cm (mean, 4.5 cm). Of the 24 patients with purely intradural tumors, four (17%) had Simpson Grade I and 19 had Simpson Grade II resections; 23 (96%) had gross total resections. Of the 11 patients with tumors extending extradurally (i.e., cavernous sinus), one (9%) patient had a Simpson Grade II resection, whereas nine (82%) had Simpson Grade III resections, with the latter being all visible tumor removed except that in the cavernous sinus. One (9%) of these 11 patients had a gross total resection, and 9 (82%) had radical resections, with the latter defined as total removal of all intradural tumor. The overall morbidity rate was 18%. There was no surgical mortality or symptomatic cerebral infarction.

Conclusion:

An accurate classification of global medial sphenoid meningiomas is mandatory to gain insight into their clinical behavior and for understanding the long-term efficacy and safety of available treatment options. Primary medial sphenoid ridge tumors consistently involve the unilateral arteries of the anterior cerebral circulation, and therefore, the resection of tumor from around these arteries is the most important operative nuance for their safe excision.