The "subdural" space: a new look at an outdated concept

Glycosaminoglycans in subdural fluid and CSF after meningeal injury

BACKGROUND

Inflammatory mechanisms have an acknowledged role in the progression of chronic subdural hematoma (CSDH) and in tissue response after subarachnoid hemorrhage (SAH). The participation of extracellular matrix, especially glycosaminoglycans, in the cellular events during tissue repair is known to be important. We studied the production of glycosaminoglycans after two types of meningeal injury-one caused by rupture of the dural border cell layer after head injury, and the other caused by SAH.

METHODS

Patients with CSDH (n = 28), subdural effusion (n = 8), and SAH (n = 33) were included in the study. Samples from subdural fluid or cerebrospinal fluid (CSF) were assayed for hyaluronic acid (HA) with an enzyme-linked assay and for sulfated glycosaminoglycans (sGAGs) with a dye-binding assay.

RESULTS

The median HA concentration was 3021 (range, 408-14,012) ng/ml in the CSDH fluid, 668 (392-3607) ng/ml in the effusion fluid, and 21.7 (5.8-195) ng/ml in the serum. In lumbar CSF after SAH, the median HA concentration was 246 (47-3686) ng/ml being 1.5-fold higher than that in control CSF. The median sGAG concentration was 52.8 (0-144) μg/ml in CSDH fluid, but only 5.32 (0-20.5) μg/ml in the effusion fluid, where the concentration was similar to that in the serum.

CONCLUSIONS

We found high, but variable, concentrations of sGAGs and HA in the CSDH and effusion fluid after head injury and HA in the CSF after SAH. Our results show that HA and sGAGs are induced after meningeal injury and that these proteins may participate in a reactive process.

History of Chronic Subdural Hematoma

Trephination or trepanation is an intentional surgical procedure performed from the Stone Age. It looks like escaping a black evil from the head. This technique is still used for treatment of chronic subdural hematoma (SDH). Now, we know the origin, pathogenesis and natural history of this lesion. The author try to explore the history of trephination and modern discovery of chronic SDH. The author performed a detailed electronic search of PubMed. By the key word of chronic SDH, 2,593 articles were found without language restriction in May 2015. The author reviewed the fact and way, discovering the present knowledge on the chronic SDH. The first authentic report of chronic SDH was that of Wepfer in 1657. Chronic SDH was regarded as a stroke in 17th century. It was changed as an inflammatory disease in 19th century by Virchow, and became a traumatic lesion in 20th century. However, trauma is not necessary in many cases of chronic SDHs. The more important prerequisite is sufficient potential subdural space, degeneration of the brain. Modifying Virchow's description, chronic SDH is sometimes traumatic, but most often caused by severe degeneration of the brain. From Wepfer's first description, nearly 350 years passed to explore the origin, pathogenesis, and fate of chronic SDH. The nature of the black evil in the head of the Stone Age is uncovering by many authors riding the giant's shoulder. Chronic SDH should be categorized as a degenerative lesion instead of a traumatic lesion.

Surgical Treatments for Chronic Subdural Hematomas: A Comprehensive Systematic Review

BACKGROUND

Chronic subdural hematomas (CSDHs) are common neurosurgical conditions among elderly patients.

OBJECTIVE

To perform a detailed critical appraisal of all randomized controlled trials (RCTs) of surgical treatments for chronic subdural hematomas and to quantify their intervention effects.

METHODS

We performed a broad search for all RCTs with no language or date restrictions, asked the authors for missing data, and applied the Cochrane methods.

RESULTS

A total of 24 RCTs involved 1900 patients and 15 comparisons. All outcomes of practical interest were analyzed. Postoperative drainage after burr-hole evacuation reduced the rate of recurrence (risk ratio 0.48, 95% confidence interval 0.34-0.66, P < 0.00001) with no other clear benefits or complications.

CONCLUSIONS

This comprehensive, best evidence-based, quantitative, systematic review indicates that the use of a closed system drainage after burr-hole evacuation reduces the rate of recurrences but has no other significant differences. The findings also suggest that: (1) treatment with twist drills is equivalent to that with burr holes; (2) the postoperative bed header in the elevated position might reduce the length of hospital stay; (3) irrigation of the subdural space with thrombin solution in patients with high risk of recurrence might reduce this risk; and (4) treatment with twist drill followed by a closed system drainage during 48 hours, instead of 96 hours, might reduce general complication rates. Most of the trials suffered from unclear or high risks of bias and many involved small samples, precluding strong and definitive conclusions.

A calvarial acute subdural hematoma migrating into the spinal canal in a young male

It is not common for an acute subdural hematoma (SDH) in the supratentorial region to show rapid resolution or migration during the clinical course. In this report, we present a rare case where the SDH in the supratentorial region was observed to rapidly migrate into the lumbar spinal canal, leading to severe radiculopathy. A 20-year-old male patient was admitted to the emergency department with severe headache after head trauma. The patient's overall condition was good, whereas his Glasgow Coma Scale score was 15 and blood pressure was normal. He had vomited 3 times after the onset of pain. No stiff neck was found, and the computed tomography showed an ASDH over the outer layer of the right hemisphere, causing a 7- to 8-mm shift. During the follow-up, the headache regressed and eventually resolved after 12 hours; however, another severe pain occurred in the lumbar region and in both legs. The pain worsened over time, progressing to sciatica in both legs. Acute SDH associated with a minor head trauma may migrate from the supratentorial compartment into the spinal canal by the help of elastic cerebral tissues in young adults and children.

[The Clinical Features of Cerebrospinal Fluid Leaks--Based on Our Experiences]

Cerebrospinal fluid (CSF) leak, which usually occurs idiopathically or traumatically as a rare situation, is a rare disease that causes orthostatic headache or idiopathic chronic subdural hematoma (CSDH). We report our therapeutic experience of consecutive 20 cases for this disease, and review the current status and problems. Consecutive 20 patients (11 women; age 44.7±12.1 years) between April, 2006 and March, 2014, who were diagnosed by MRI and/or CT myelography (CTM), were evaluated retrospectively about clinical features. The main symptoms were as follows: orthostatic headache only; 10 cases, orthostatic headache with CSDH; 6, and none-orthostatic headache accompanied with CSDH; 4. As a treatment, direct surgeries were performed in 2 cases. Epidural blood patch (EBP) was applied in 14 cases (direct surgery was performed finally in the early one case), and widespread EBP with a single lumbar entry point utilizing an intravenous catheter was performed especially in the latest 9 cases. Another 5 cases were treated simply with the administration of a drip infusion regardless of the drainage for CSDH. Of 10 cases suffering from headache only, the headache disappeared completely or it was relieved in 9 cases. Of 10 cases accompanied with CSDH, recurrence of hematoma was prevented in all cases with a drip infusion after the drainage in one case and EBP after the drainage in another 9 cases. It was certified that we could diagnose CSF leak correctly with MRI and/or CTM and control this disorder almost completely with widespread EBP utilizing an intravenous catheter.

Spontaneous subdural fluid collection following aneurysmal subarachnoid hemorrhage: subdural hygroma or external hydrocephalus?

BACKGROUND

Subdural fluid collections (hygromas and effusions) in adults are usually seen following head trauma or overdrainage of cerebrospinal fluid (CSF) after CSF diversion procedures. We report an unusual case of subdural fluid collection that developed spontaneously 5 days after an aneurysmal subarachnoid hemorrhage (SAH). This patient neither had permanent CSF diversion procedure nor history of significant head trauma during her clinical course.

METHODS

This study is a Case report of the patient suffering from an SAH.

RESULTS

A 71-year-old woman suffered an SAH from a ruptured right-sided posterior communicating artery aneurysm. Computed tomography (CT) demonstrated diffuse SAH and signs of early hydrocephalus that did not require treatment. The aneurysm was treated with endovascular coil occlusion without any complications. Throughout her hospital course, she remained alert without neurological deficits. A large subdural fluid collection was discovered incidentally during a routine CT scan of the brain 5 days after the SAH. The patient remained asymptomatic; therefore, the collection was treated conservatively. It resolved spontaneously at five days after the initial diagnosis.

CONCLUSION

Subdural fluid collections following SAH can occur as a result of head trauma, external hydrocephalus, or as a treatment complication of CSF shunting and craniotomies. It is critical to differentiate simple hygromas from external hydrocephalus since their response to CSF diversion is entirely different.

A blackhole over brain: Interdural hematoma - A challenging diagnosis

Hematoma in between two dura leaves, named as 'interdural hematoma', is a very rare entity in adulthood. Interdural hematoma may emerge spontaneously or secondary to coagulopathies. A 61-year-old male patient, who had a medical history of alcoholic cirrhosis, presented with interdural hematoma. The case has been discussed with a literature review about diagnostic and therapeutic approaches in this pathology.

Histological structure of the medial and lateral walls of cavernous sinus in human fetuses

PURPOSE

The aim of this study is to elucidate the architecture of these fine structures in human fetuses.

METHODS

The histological examination of medial wall (MW) and lateral wall (LW) was performed in 15 normal human fetuses. Eleven fetuses were female and four were male. The gestational age ranged between 14 and 35 weeks. The weight ranged between 180 and 1750 g. The wall samples (two MW and two LW from each fetus) were obtained by microsurgical technique and underwent histological examination. Each wall was examined for the structure and composition of collagen and elastic fibers, ganglions, peripheral nerves, and vessels.

RESULTS

A total of 60 wall samples (30 MW and 30 LW) were examined in 15 fetuses. Loose connective tissue composed of type III collagen was observed in both of the walls. Elastic fibers were observed only in three wall samples (two MW and one LW). Ganglion was detected in 11 samples (nine in LW and two in MW), and peripheral nerve was found in 28 walls (18 LW and 10 MW). Vessels were observed in 51 samples (26 LW and 25 MW). None of the walls was stained with type I collagen.

CONCLUSIONS

The structure of LW and MW of the cavernous sinus (CS) in fetuses is mainly composed of collagen tissue while some elastic fibers are supported by this tissue. Type III collagen is the main component of fetal CS walls. Because of the weak histological structure, CS may be more prone to tumor invasion in infants.

Mechanics of the brain: perspectives, challenges, and opportunities

The human brain is the continuous subject of extensive investigation aimed at understanding its behavior and function. Despite a clear evidence that mechanical factors play an important role in regulating brain activity, current research efforts focus mainly on the biochemical or electrophysiological activity of the brain. Here, we show that classical mechanical concepts including deformations, stretch, strain, strain rate, pressure, and stress play a crucial role in modulating both brain form and brain function. This opinion piece synthesizes expertise in applied mathematics, solid and fluid mechanics, biomechanics, experimentation, material sciences, neuropathology, and neurosurgery to address today’s open questions at the forefront of neuromechanics. We critically review the current literature and discuss challenges related to neurodevelopment, cerebral edema, lissencephaly, polymicrogyria, hydrocephaly, craniectomy, spinal cord injury, tumor growth, traumatic brain injury, and shaken baby syndrome. The multi-disciplinary analysis of these various phenomena and pathologies presents new opportunities and suggests that mechanical modeling is a central tool to bridge the scales by synthesizing information from the molecular via the cellular and tissue all the way to the organ level.

Postoperative intraspinal subdural collections after pediatric posterior fossa tumor resection: incidence, imaging, and clinical features

BACKGROUND AND PURPOSE

Postoperative intraspinal subdural collections in children after posterior fossa tumor resection may temporarily hinder metastasis detection by MR imaging or CSF analysis, potentially impacting therapy. We investigated the incidence, imaging and clinical features, predisposing factors, and time course of these collections after posterior fossa tumor resection.

MATERIALS AND METHODS

Retrospective review of postoperative spine MRI in 243 children (5.5 ± 4.6 years of age) from our clinical data base postresection of posterior fossa tumors from October 1994 to August 2010 yielded 37 (6.0 ± 4.8 years of age) subjects positive for postoperative intraspinal subdural collections. Their extent and signal properties were recorded for postoperative (37/37), preoperative (15/37), and follow-up spine (35/37) MRI. Risk factors were compared with age-matched internal controls (n = 37, 5.9 ± 4.5 years of age). Associations of histology, hydrocephalus and cerebellar tonsillar herniation, and postoperative intracranial subdural collections with postoperative intraspinal subdural collections were assessed by the Fisher exact test or χ(2) test. The association between preoperative tumor volume and postoperative intraspinal subdural collections was assessed by the Wilcoxon rank sum test.

RESULTS

The overall incidence of postoperative intraspinal subdural collections was 37/243 (15.2%), greatest ≤7 days postoperatively (36%); 97% were seen 0-41 days postoperatively (12.9 ± 11.0 days). They were T2 hyperintense and isointense to CSF on T1WI, homogeneously enhanced, and resolved on follow-up MR imaging (35/35). None were symptomatic. They were associated with intracranial subdural collections (P = .0011) and preoperative tonsillar herniation (P = .0228).

CONCLUSIONS

Postoperative intraspinal subdural collections are infrequent and clinically silent, resolve spontaneously, and have a distinctive appearance. Preoperative tonsillar herniation appears to be a predisposing factor. In this series, repeat MR imaging by 4 weeks documented improvement or resolution of these collections in 88%.

Acute spinal subdural hematoma after vigorous back massage: a case report and review of literature

STUDY DESIGN

A case report and review of literature.

OBJECTIVE

We report on a patient with traumatic spinal subdural hematoma after vigorous back massage while on vacation.

SUMMARY OF BACKGROUND DATA

Traumatic spinal subdural hematoma is extremely rare, and to our knowledge, this is the first case reported after violent back massage. We emphasize a high index of suspicion for early recognition and treatment for a good neurological recovery.

METHODS

A 41-year-old male was brought to our hospital with severe back pain, motor and sensory impairments of the bilateral lower extremities, and urinary dysfunction after vigorous back massage. Magnetic resonance images revealed an acute spinal subdural hematoma in the thoracolumbar region. After careful monitoring of his neurological status, the patient was successfully managed with conservative treatment.

RESULTS

After 2 weeks of hospitalization, complete motor power recovery was achieved with only minor sensory deficit. At a follow-up of more than 12 months, the patient has no residual neurological deficits.

CONCLUSION

Spinal subdural hematoma secondary to physical trauma is quite rare. This case brings new information that traumatic spinal subdural hematoma can be caused by violent massage.

LEVEL OF EVIDENCE

N/A.

The minimally invasive endoscopic management of septated chronic subdural hematomas: surgical technique

BACKGROUND

Fibrin membranes and compartmentalization within the subdural space are a frequent cause of failure in the treatment of chronic subdural hematomas (CSH). This specific subtype of CSH classically requires craniotomy, which carries significant morbidity and mortality rates, particularly in elderly patients. In this work, we describe a minimally invasive endoscopic alternative.

METHODS

Under local scalp anesthesia, a rigid endoscope is inserted through a parietal burr hole in the subdural space to collapse fibrin septa and cut the internal membrane. It also allows cauterization of active bleedings and the placement of a drain under direct visualization.

CONCLUSIONS

The endoscopic treatment of septated CSH represents a minimally invasive alternative to craniotomy especially for the internal membranectomy.

[Clinical and radiological studies of seizure in chronic subdural hematoma--case control study]

We studied the mechanism underlying seizure induction in patients with chronic subdural hematoma. In our study population of 1,009 patients with chronic subdural hematoma, 26 (2.6%) had seizure-related complications. Six of them had already been diagnosed with epilepsy (4 patients) or suspected of having secondary epilepsy (2 patients) after experiencing traffic accidents or cerebral bleeding. Twenty patients (seizure group) had been tentatively diagnosed as having hematoma-induced convulsion. Of the remaining 989 patients without convulsion, 40 randomly sampled patients were included in the non-seizure group by matching with clinical terms. Intergroup comparisons showed that patients with dementia were more common in the seizure group than in the non-seizure group; however, no intergroup differences were observed for other clinical parameters. Radiological examinations showed that bilateral hematomas were relatively more common and sulcal hyperintensity on FLAIR MR images was significantly more frequent in the seizure group than in the non-seizure group. Interestingly, many patients presenting with sulcal hyperintensity exhibited mixed-density hematomas on CT images. These findings suggest the mechanism by which hematoma content infiltrates into the brain parenchyma and the subsequent induction of convulsions by the stimulatory component.

Influence of Gender on Occurrence of Chronic Subdural Hematoma; Is It an Effect of Cranial Asymmetry?

Objective

Chronic subdural hematoma (CSDH) is a condition mostly present in older people. Men are more commonly affected than women. Several theories about male predominance could not enough to explain the reason for male predominance on CSDH. The purpose of this study is to find out whether there were any differences in the anatomy of cranium, which may contribute the pathogenesis or risk factors of CSDH.

Methods

The study population was consisted of 87 patients with CSDH and 100 patients with transient ischemic attack (TIA) from 2006 to 2013. We classified into four groups; group A (CSDH male 47), group B (CSDH female 40), group C (TIA male 50), and group D (TIA female 50). We measured the size of the cranium in the computed tomography scans, retrospectively. We define the difference of cranium (Dc), which is difference between the right and left radiuses.

Results

The Dc was significantly higher in patients with CSDH (group A and B)(p=0.03). The mean Dc was 3.49 mm in CSDH group (group A and B) and 2.14 mm in TIA group (group C and D). The mean Dc of CSDH group was significantly larger than that of TIA group (by t-test, p<0.01).

Conclusion

Size and asymmetry of the cranium may be a risk factor of CSDH. Gender differences in the anatomy of cranium may contribute pathogenesis of CSDH.

Chronic subdural haematoma: modern management and emerging therapies

Chronic subdural haematoma (CSDH) is one of the most common neurological disorders, and is especially prevalent among elderly individuals. Surgical evacuation is the mainstay of management for symptomatic patients or haematomas exerting significant mass effect. Although burr hole craniostomy is the most widely practised technique worldwide, approximately 10-20% of surgically treated patients experience postoperative recurrence necessitating reoperation. Given the increasing incidence of CSDH in a growing elderly population, a need exists for refined techniques that combine a minimally invasive approach with clinical efficacy and cost-effectiveness. In addition, nonsurgical treatment modalities, such as steroids, are attracting considerable interest, as they have the potential to reduce postoperative recurrence or even replace the need for surgery in selected patients. This Review provides an overview of the contemporary management of CSDH and presents considerations regarding future approaches that could further optimize patient care and outcomes.

Contrast-enhanced FLAIR (fluid-attenuated inversion recovery) for evaluating mild traumatic brain injury

PURPOSE

To evaluate whether adding a contrast-enhanced fluid-attenuated inversion recovery (FLAIR) sequence to routine magnetic resonance imaging (MRI) can detect additional abnormalities in the brains of symptomatic patients with mild traumatic brain injury.

MATERIALS AND METHODS

Fifty-four patients with persistent symptoms following mild closed head injury were included in our retrospective study (M ∶ F =  32 ∶ 22, mean age: 59.8 ± 16.4, age range: 26-84 years). All MRI examinations were obtained within 14 days after head trauma (mean: 3.2 ± 4.1 days, range: 0.2-14 days). Two neuroradiologists recorded (1) the presence of traumatic brain lesions on MR images with and without contrast-enhanced FLAIR images and (2) the pattern and location of meningeal enhancement depicted on contrast-enhanced FLAIR images. The number of additional traumatic brain lesions diagnosed with contrast-enhanced FLAIR was recorded. Correlations between meningeal enhancement and clinical findings were also evaluated.

RESULTS

Traumatic brain lesions were detected on routine image sequences in 25 patients. Three additional cases of brain abnormality were detected with the contrast-enhanced FLAIR images. Meningeal enhancement was identified on contrast-enhanced FLAIR images in 9 cases while the other routine image sequences showed no findings of traumatic brain injury. Overall, the additional contrast-enhanced FLAIR images revealed more extensive abnormalities than routine imaging in 37 cases (p<0.001). In multivariate logistic regression analysis, subdural hematoma and posttraumatic loss of consciousness showed a significant association with meningeal enhancement on contrast-enhanced FLAIR images, with odds ratios 13.068 (95% confidence interval 2.037 to 83.852), and 15.487 (95% confidence interval 2.545 to 94.228), respectively.

CONCLUSION

Meningeal enhancement on contrast-enhanced FLAIR images can help detect traumatic brain lesions as well as additional abnormalities not identified on routine unenhanced MRI. Therefore contrast-enhanced FLAIR MR imaging is recommended when a contrast MR study is indicated in a patient with a symptomatic prior closed mild head injury.

Acute subdural hematoma from bridging vein rupture: a potential mechanism for growth

Most acute subdural hematomas (ASDHs) develop after rupture of a bridging vein or veins. The anatomy of the bridging vein predisposes to its tearing within the border cell layer of the dura mater. Thus, the subdural hematoma actually forms within the dura. The hematoma grows by continued bleeding into the border cell layer. However, the venous pressure would not be expected to cause a large hematoma. Therefore, some type of mechanism must account for the hematoma's expansion.

Cerebral venous pressure (CVP) has been demonstrated in animal models to be slightly higher than intracranial pressure (ICP), and CVP tracks the ICP as pressure variations occur. The elevation of CVP as the ICP increases is thought to result from an increase in outflow resistance of the terminal portion of the bridging veins. This probably results from a Starling resistor model or, less likely, from a muscular sphincter.

A hypothesis is derived to explain the mechanism of ASDH enlargement. Tearing of one or more bridging veins causes these vessels to bleed into the dural border cell layer. Subsequent ICP elevation from the ASDH, cerebral swelling, or other cause results in elevation of the CVP by increased outflow resistance in the intact bridging veins. The increased ICP causes further bleeding into the hematoma cavity via the torn bridging veins. Thus, the ASDH enlarges via a positive feedback mechanism.

Enlargement of an ASDH would cease as blood within the hematoma cavity coagulates. This would stop the dissection of the dural border cell layer, and pressure within the hematoma cavity would equalize with that in the torn bridging vein or veins.

Characterization of chronic subdural hematoma fluid proteome

BACKGROUND

Chronic subdural hematoma (CSDH) is commonly caused by head injury, but the progression of CSDH is recognized as an inflammatory process. The protein composition of the CSDH fluid has not been fully elucidated, nor has the contribution of its components to the enlargement of the hematoma cavity and to its chronic manifestation.

OBJECTIVE

To characterize the protein content of CSDH fluid and study the differences between CSDH fluid and serum to identify proteins putatively involved in the pathogenesis of CSDH.

METHODS

CSDH fluid and serum of 5 patients were investigated with 2-dimensional gel electrophoresis followed by glycosylation-specific fluorescence staining and mass spectrometry.

RESULTS

Two-dimensional gel electrophoresis revealed approximately 1100 protein spots in the CSDH fluid. We identified 213 spots representing 57 different proteins, most of which were glycosylated. The comparison with serum revealed 11 proteins with elevated levels in the CSDH fluid including carbonic anhydrase I, catalase, ferritin light chain, fibrinogen (α, β, γ), hemoglobin (α, β), malate dehydrogenase, peroxiredoxin 2, and transforming growth factor-β-induced protein ig-h3. The levels of haptoglobin and a fragment of complement C4 were decreased. Changes in spot positions were detected for apolipoprotein A1 and a fragment of complement C3.

CONCLUSION

The hematoma fluid originates mainly from blood and the results suggest the involvement of coagulation and fibrinolysis cascades. However, proteins with a potential role in CSDH pathogenesis were detected including carbonic anhydrase I, transforming growth factor-β-induced protein ig-h3, and the altered components of the complement system. Inflammation and fibrosis indicate targets for further studies in the pathogenesis of CSDH.

Dural fibroblasts play a potential role in headache pathophysiology

Nociceptive signaling from the meninges is proposed to contribute to many forms of headache. However, the events within the meninges that drive afferent activity are not clear. Meningeal fibroblasts are traditionally thought to produce extracellular proteins that constitute the meninges but not to contribute to headache. The purpose of these studies was to determine whether dural fibroblasts release factors that activate/sensitize dural afferents and produce headache-like behavior in rats. Dura mater was removed from male rats and dural fibroblasts were cultured. Fibroblast cultures were stimulated with vehicle or lipopolysaccharide (LPS), washed, and conditioned media was collected. Fibroblast media conditioned with vehicle or LPS was applied to retrogradely labeled rat dural trigeminal ganglion neurons in vitro. Patch-clamp electrophysiology was performed to determine whether conditioned media activated/sensitized dural afferents. A preclinical behavioral model was used where conditioned media was applied directly to the rat dura to determine the presence of cutaneous facial and hind-paw allodynia. Conditioned media was also tested for interleukin-6 (IL-6) content using an enzyme-linked immunosorbent assay. Application of LPS-conditioned fibroblast media to dural afferents produced a significant increase in action potential firing as well as cutaneous facial and hind-paw allodynia when this media was applied to the dura. Finally, stimulation of cultured fibroblasts with LPS increased IL-6 levels in the media. These findings demonstrate that fibroblasts stimulated with LPS release factors capable of activating/sensitizing dural afferents. Further, they suggest that fibroblasts play a potential role in the pathophysiology of headache.

Effect of inner membrane tearing in the treatment of adult chronic subdural hematoma: a comparative study

The postoperative results of chronic subdural hematoma (CSDH) procedures using catheterization and tearing of inner membrane (CTIM) technique have not previously been discussed in the literature. This article compares the effects of CTIM technique on brain re-expansion and re-accumulation with cases operated on with a burr-hole craniotomy and outer membrane incision (BCOMI) technique. The study involved operations on 144 patients (Group 1) using the CTIM technique and 108 patients (Group 2) using the BCOMI technique. In the operations using the CTIM technique in Group 1, the mean effusion measured in the subdural space (SDS) was 10.0 ± 0.2 mm, and for Group 2, 14.3 ± 0.6 mm in the postoperative period on the first and third days and this difference was found to be significant (p < 0.05). The means were 6.6 ± 0.2 mm for Group 1 and 10.3 ± 0.5 mm for Group 2 on the seventh day (p < 0.05). Recurrence rate was 8.3% in Group 2 and 0 in Group 1. This difference was statistically significant (p = 0001). The length of hospital stay was 7.0 ± 0.1 days for the Group 1 and 8.8 ± 0.2 days for Group 2 and this difference was significant (p < 0.05). These results indicate that the CTIM technique is preferable because it results in earlier re-expansion, lower recurrence, less subdural effusion and pneumocephalus, and shorter hospital stays.

Spinal subdural hematoma following cranial subdural hematoma : a case report with a literature review

Coexistence of cranial and spinal subdural hematomas is rare and only a few cases have been reported in the literature. Herein, we report a case of cranial and spinal subdural hematomas after previous head trauma. As the pathogenesis of simultaneous intracranial and spinal subdural hematoma yet remains unclear, we developed an alternative theory to those proposed in the literature for their coexistence, the migration of blood through the subdural space.

The Meningo-Orbital Band: Microsurgical Anatomy and Surgical Detachment of the Membranous Structures through a Frontotemporal Craniotomy with Removal of the Anterior Clinoid Process

Objective To describe the microanatomy of the meningo-orbital band (MOB) and its associated membranes, and propose a stepwise method for their detachment while minimizing potential complications. Design Cadaveric and prospective clinical. Setting Microneurosurgery Skull Base Laboratory, Weill Cornell Medical College (New York, NY) and Shiroyama Hospital (Osaka, Japan). Participants Five preserved cadaveric heads (10 sides) and five patients requiring surgical detachment of the MOB in 2012. Results MOB detachment and subsequent extradural anterior clinoidectomies were successfully performed on five clinical cases. Detachment of the MOB was accomplished using a four-step dissection based on the structure's detailed microanatomy and included (1) partial removal of the lateral wall of the superior orbital fissure, (2) incising of the lateral periosteal dura of the superior orbital fissure, (3) peeling off the dura propria of the temporal lobe from the inner cavernous membrane, and (4) fully detaching the exposed MOB from the periorbita. Conclusion Understanding the complex microanatomy of these structures enabled a safe and effective stepwise detachment of the MOB. We recommend that surgeons possess sufficient anatomical knowledge before surgically manipulating this structure.

Migration of traumatic intracranial subdural hematoma to lumbar spine causing radiculopathy

Background:

There have been rare reports of intracranial subdural hematoma (SDH) that migrated into the spine. All previous cases have been surgically managed and in this case report, we describe the first case of conservatively managed spinal hematoma secondary to migratory intracranial SDH.

Case Description:

A 26-year-old male presented with a left tentorial SDH after blunt trauma. He was conservatively managed and discharged home. He presented 8 days later with worsening lower back pain that was found to be secondary to a spinal SDH.

Conclusion:

Spinal hematomas can be a serious sequelae of migrated intracranial hematomas. Tentorial and other caudally located intracranial hematomas may be more prone to this phenomenon.

Nontraumatic intradural and subdural hemorrhage and hypoxic ischemic encephalopathy in fetuses, infants, and children up to three years of age: analysis of two audits of 636 cases from two referral centers in the United Kingdom

We analyzed the presence or absence of intradural hemorrhage (IDH) and subdural hemorrhage (SDH) and the degree of hypoxic-ischemic encephalopathy (HIE) in the brain of all nonmacerated fetuses of >24 weeks, neonates, and children up to 3 years of age who died of natural causes over a defined period. We looked into the cause of death and the performance of cardiopulmonary resuscitation in our cohort. The IDH was classified as macroscopic or negative/microscopic only; the HIE was classified as absent, indeterminate, or definite. In fetuses, SDH with IDH was present in 22%; IDH alone was present in 31%, and there was no or minimal hemorrhage in 47% of cases. In infants and children SDH with IDH was present in 19%; IDH alone was present in the 32%, and there was no or minimal hemorrhage in 49% of cases. There was a statistically significant correlation between SDH and HIE, especially in infants and children (P < 0.001). When cases were grouped per age, a significant association between age and hemorrhage (P < 0.0001) was demonstrated, SDH being more common in infants ≤1 month corrected age. Intradural hemorrhage can be the source of thin-film SDH in fetuses, infants, and young children. The presence of SDH is associated with hypoxia. Intradural and subdural hemorrhages are more common in autopsies of infants under 1 month corrected age. Although more rare, they can also be found in children between 1 month and 3 years of age in the absence of trauma.

Epidemiological characteristics of 778 patients who underwent surgical drainage of chronic subdural hematomas in Brasília, Brazil

BACKGROUND

Chronic subdural hematomas (CSDHs) are common in neurosurgical practice. There are no publications that report large series of the epidemiological characteristics of this pathology in Brazil. The purpose is to describe a large series of surgical cases and analyze the epidemiological and clinical characteristics.

METHODS

We retrospectively analyzed patients with CSDH admitted into Neurosurgical Services at the Hospital de Base do Distrito Federal, Brasília, Brazil from 2006 to 2011. Age, sex, clinical feature, etiology, surgical procedure, side, clinical outcome, and recurrence were reviewed. Statistical tests were used to analyze data, and P < 0.05 was considered statistically significant.

RESULTS

The series included 778 patients. There were 643 (82.6%) male patients with a mean age of 64.3 ± 15.9 (range, 14-93) years. The principal symptom was headache (58.9%). The most frequent origin was a fall (282 cases, 36.2%), but the origin remained unclear in 281 (36.1%) patients. Mild head injury occurred in 540 (69.4%) cases. Burr holes with drainage were used as the surgical procedure in 96.5% patients, and 687 (88.3%) patients had a positive outcome. Mortality was 0%. Recurrence was observed in 42 cases.

CONCLUSIONS

The occurrence of CSDHs is more common in elderly men. Treatment with burr holes and drainage is a simple and safe method for treatment. In our experience, CSDH presents decreased morbidity and mortality.

Chronic subdural hematoma associated with the middle fossa arachnoid cyst: pathogenesis and review of its management

BACKGROUND

The pathogenesis of chronic subdural hematoma (CSDH) associated with an arachnoid cyst (AC) is still not clear. We propose an origin of initial bleeding of CSDH in patients with AC based on our experience and discuss the management of this disease.

MATERIALS AND METHODS

The total number of operations included in this study was 23. Eleven cases were indicated because of associated CSDH (group 1), and the other cases were due to different reasons (group 2). The relationship of the AC and dura was evaluated in patients who did not have CSDH (group 2) because patients with CSDH would have had structural changes of AC due to hematoma.

RESULTS

In group 1, the age distribution was from 8 to 61 years (mean 23.0). The development of CSDH was not related with Galassi types. The hematomas were located outside of the outer cyst membrane in six patients and both inside and outside in three patients. In two patients, the location could not be reviewed. After suspicion of the outer cyst membrane as the origin of the bleeding site, we found small bridging vessels between the dura and outer cyst membrane in three of five consecutive patients in group 2.

CONCLUSIONS

Based on our surgical experience of AC cyst, we found small bridging vessels between the dura and outer membrane of the AC. We suggested that these small vessels are the source of initial bleeding leading to CSDH in AC.

Infections of the spinal subdural space in children: a series of 11 contemporary cases and review of all published reports. A multinational collaborative effort

INTRODUCTION

Positioned anatomically between the spinal epidural space and the intramedullary compartment, the spinal subdural space remains the least common area of localized infection in the central nervous system. Infectious processes of the subdural spinal space include subdural spinal empyema, subdural spinal abscess, infected spinal subdural cyst, and infectious spinal subdural cyst. To date, there has been no systematic review of these entities in children, with the cumulative knowledge of the pathophysiologic, microbiologic, and demographic characteristics of these infections relegated solely to few small series and case reports.

METHODS

A series of 11 recent cases culled from the collaboration of international authors are presented. In addition, an exhaustive MEDLINE search and manual review of the international literature was performed, identifying a total of 73 cases of spinal subdural infections in patients under the age of 21. Data of interest include the age, sex, signs, and symptoms at presentation, spinal location of infection, presence of spinal dysraphism, and other comorbidities, offending organism, treatment, outcome, and follow-up.

RESULTS

Patients ages ranged from 4 weeks to 20 years (mean, 6.5 years). Males outnumbered females by a ratio of 2:1. Over half (53 %) of spinal subdural infections in children were associated with spinal dysraphism or other congenital abnormalities of the spine. The commonest organism to infect the spinal subdural space in children is mycobacterium tuberculosis and the thoracic spinal region was most commonly infected.

CONCLUSIONS

The disease is usually treated surgically, although a more expectant approach consisting of antibiotics and observation has also been proposed.

The intracranial arachnoid mater : a comprehensive review of its history, anatomy, imaging, and pathology

INTRODUCTION

The arachnoid mater is a delicate and avascular layer that lies in direct contact with the dura and is separated from the pia mater by the cerebrospinal fluid-filled subarachnoid space. The subarachnoid space is divided into cisterns named according to surrounding brain structures.

METHODS

The medical literature on this meningeal layer was reviewed in regard to historical aspects, etymology, embryology, histology, and anatomy with special emphasis on the arachnoid cisterns. Cerebrospinal fluid dynamics are discussed along with a section devoted to arachnoid cysts.

CONCLUSION

Knowledge on the arachnoid mater and cerebrospinal fluid dynamics has evolved over time and is of great significance to the neurosurgeon in clinical practice.

The pathophysiology of brain swelling associated with subdural hemorrhage: the role of the trigeminovascular system

INTRODUCTION

This paper reviews the evidence in support of the hypothesis that the trigeminal system mediates brain swelling associated with subdural bleeding. The trigeminovascular system has been extensively studied in migraine; it may play an important but under-recognized role in the response to head trauma. Nerve fibers originating in trigeminal ganglion cells are the primary sensors of head trauma and, through their collateral innervation of the intracranial and dural blood vessels, are capable of inciting a cascade of vascular responses and brain swelling. The extensive trigeminal representation in the brainstem initiates and augments autonomic responses. Blood and tissue injury in the dura incite neurogenic inflammatory responses capable of sensitizing dural nerves and potentiating the response to trauma.

DISCUSSION

The trigeminal system may provide the anatomo-physiological link between small-volume, thin subdural bleeds and swelling of the underlying brain. This physiology may help to explain the poorly understood phenomena of "second-impact syndrome," the infant response to subdural bleeding (the "big black brain"), as well as post-traumatic subdural effusions. Considerable age-specific differences in the density of dural innervation exist; age-specific responses of this innervation may explain differences in the brain's response to trauma in the young. An understanding of this pathophysiology is crucial to the development of intervention and treatment of these conditions. Antagonists to specific neuropeptides of the trigeminal system modify brain swelling after trauma and should be further explored as potential therapy in brain trauma and subdural bleeding.

The grand unifying theory of bright echoes in the fetal and neonatal brain

The purpose of this presentation is to illustrate that the high-amplitude reflecting structures in the fetal and neonatal brain can be explained by the echogenicity of their leptomeningeal coverings or leptomeningeal origins. The leptomeninges, especially the pia mater, constitute the "grand unifying theory of bright reflectors" in the fetal and neonatal brain. Images from fetal and neonatal sonograms were selected to illustrate the objectives above.

Adult human brain neural progenitor cells (NPCs) and fibroblast-like cells have similar properties in vitro but only NPCs differentiate into neurons

The ability to culture neural progenitor cells from the adult human brain has provided an exciting opportunity to develop and test potential therapies on adult human brain cells. To achieve a reliable and reproducible adult human neural progenitor cell (AhNPC) culture system for this purpose, this study fully characterized the cellular composition of the AhNPC cultures, as well as the possible changes to this in vitro system over prolonged culture periods. We isolated cells from the neurogenic subventricular zone/hippocampus (SVZ/HP) of the adult human brain and found a heterogeneous culture population comprised of several types of post-mitotic brain cells (neurons, astrocytes, and microglia), and more importantly, two distinct mitotic cell populations; the AhNPCs, and the fibroblast-like cells (FbCs). These two populations can easily be mistaken for a single population of AhNPCs, as they both proliferate under AhNPC culture conditions, form spheres and express neural progenitor cell and early neuronal markers, all of which are characteristics of AhNPCs in vitro. However, despite these similarities under proliferating conditions, under neuronal differentiation conditions, only the AhNPCs differentiated into functional neurons and glia. Furthermore, AhNPCs showed limited proliferative capacity that resulted in their depletion from culture by 5–6 passages, while the FbCs, which appear to be from a neurovascular origin, displayed a greater proliferative capacity and dominated the long-term cultures. This gradual change in cellular composition resulted in a progressive decline in neurogenic potential without the apparent loss of self-renewal in our cultures. These results demonstrate that while AhNPCs and FbCs behave similarly under proliferative conditions, they are two different cell populations. This information is vital for the interpretation and reproducibility of AhNPC experiments and suggests an ideal time frame for conducting AhNPC-based experiments.

The cranial dura mater: a review of its history, embryology, and anatomy

INTRODUCTION

The dura mater is important to the clinician as a barrier to the internal environment of the brain, and surgically, its anatomy should be well known to the neurosurgeon and clinician who interpret imaging.

METHODS

The medical literature was reviewed in regard to the morphology and embryology of specifically, the intracranial dura mater. A historic review of this meningeal layer is also provided.

CONCLUSIONS

Knowledge of the cranial dura mater has a rich history. The embryology is complex, and the surgical anatomy of this layer and its specializations are important to the neurosurgeon.

Complications of delayed cranial repair after decompressive craniectomy in children less than 1 year old

BACKGROUND

Decompressive craniectomy is an effective treatment option in case of refractory intracranial hypertension after severe head injury. The incidence of complications following cranial repair after decompressive craniectomy for traumatic brain injury is not negligible, particularly in infants and young toddlers. However, only a few dedicated papers can be found in the literature.

METHOD

We describe the complications observed in two boys and one girl under 1 year of age that were treated in the last decade by hemicranial decompressive craniotomy and enlarging hemispheric duraplasty, and subsequent cranial repair by means of autologous bone-flap replacement.

FINDINGS

Despite good clinical and neurological outcome, the postoperative clinical course was complicated in all cases by early or late evidence of subdural fluid collections associated to the occurrence of hydrocephalus and causing recurrent dislocation and progressive resorption of the autologous bone flap.

CONCLUSIONS

Infants less than 1 year old, undergoing decompressive craniectomy after traumatic brain injury, experience a high rate of complications following subsequent cranial repair. Subdural collections and resorption of the autologous bone flap are to be considered as extremely common complications.

Subdural hematoma of the posterior fossa due to posterior communicating artery aneurysm rupture

Background:

We describe an unusual presentation of a ruptured aneurysm of the posterior communicating artery with an acute subdural hematoma (SDH) located in the posterior fossa. We also reviewed the literature, focusing on the location of this intracranial hematoma.

Case Description:

An 83-year-old woman was admitted to our institution with recent sudden headache and dizziness. Magnetic resonance imaging showed a thin collection of blood in the subdural space adjacent to the clivus, along the wall of the posterior fossa, and at the cervical spine level. A right posterior communicating artery aneurysm was diagnosed using computed tomography angiography and digital subtraction angiography. The aneurysm had two lobes, one of which was attached to the right dorsum sellae. The aneurysm was occluded by stent-assisted coil embolization. The patient was discharged 3 weeks after admission with absence of neurological deficit.

Conclusion:

A ruptured aneurysm of the posterior communicating artery may cause an acute SDH.

Safety of the nonabsorbable dural substitute in decompressive craniectomy for severe traumatic brain injury

BACKGROUND

Artificial dural substitutes are increasingly being used in decompressive craniectomy to prevent peridural fibrosis and facilitate cranioplasty for patients with head injury. The safety of the dural substitute should be systemically evaluated. We focus on Neuro-Patch (B. Braun, Boulogne, France), a nonabsorbable substitute and commonly used by neurosurgeons.

METHODS

In this retrospective study, 132 patients undergoing 135 craniectomies and cranioplasties for traumatic brain injury were enrolled. We subdivided the operations into two groups on the basis of whether Neuro-Patch was used (N = 50) or not (N = 85). Risk factors of neurosurgical site infection were assessed first. Then, we compared the occurrence of infective, hemorrhagic, and hydrodynamic morbidities after craniectomy and cranioplasty between the two groups.

RESULTS

The incidence of neurosurgical site infection after craniectomy or cranioplasty showed no intergroup difference (p = 1.000). Postoperatively, extra-axial hematoma, which consists of subdural or epidural hematoma, occurred in 9 of 50 craniectomies (18.00%) with Neuro-Patch and 3 of 85 craniectomies (3.53%) without Neuro-patch, which was significantly different (p = 0.009). The rates of hydrodynamic morbidities (subdural hygroma or cerebrospinal fluid leakage) after the procedures were similar between the two groups.

CONCLUSIONS

The use of Neuro-Patch does not increase the incidence of neurosurgical site infection and hydrodynamic complications, including subdural hygroma and cerebrospinal fluid leakage, after decompressive craniectomy or cranioplasty for severe traumatic brain injury. However, extra-axial hematoma at the site of craniectomy is more often encountered in patients with Neuro-Patch and forms a compressive lesion on the adjacent brain.