Temporal sylvian fissure arachnoid cyst in children: treatment outcome following microsurgical cyst fenestration with special emphasis on cyst reduction and subdural collection.

OBJECTIVES: Controversy remains regarding surgical managements of sylvian fissure arachnoid cyst (SFAC). This review presents our experience in the microsurgical fenestration of pediatric patients with SFAC to define surgical indication, and risks and benefits with special emphasis on postoperative subdural fluid collection (SDFC) and cyst size reduction. METHODS: Thirty-four children with SFAC who underwent microsurgical cyst fenestration at a single institution over a 10-year period were retrospectively reviewed for their clinical presentation, neuroimaging findings, and postsurgical course. The SFACs were classified by a novel grading system based on the degree of arachnoid cyst extension from the sylvian fissure to the insular cistern shown on MR images: grade 0 - little or no prominence of sylvian fissure, grade I - SFAC confined to the sylvian fissure, grade II - SFAC partially extending to the insular cistern, grade III - SFAC extending to the entire insular cistern. RESULTS: There were 26 males and 8 females. SFAC was present in the left side in 24. Twelve patients presented with cyst rupturing to the subdural space. Cyst grading did not show significant difference compared with rupture status (p > 0.9). All patients underwent microsurgical cyst fenestration. Postoperative SDFC is common but often resolved overtime in two-thirds of the cases with the mean average of 6 months. However, 3 patients had symptomatic postoperative SDFC and needed reoperation shortly after the first operation. Microsurgical cyst fenestrations for SFAC effectively resolved the presenting symptoms and often showed restorations of intracranial structures on follow-up imaging. Cyst resolution or reduction greater than 75% was noted in 61.8% of the patients postoperatively which was noted in a half of the SFAC of children even with age of 11 years or older. During the follow-up, no cyst recurrence or SDFC was noted. Patients with greater surgical reduction of cyst size tended to occur in younger children, and those with lower MR grade. CONCLUSION: Our results showed a high reduction rate of SFAC and brain re-expansion after microsurgical fenestration together with symptomatic improvements regardless the patient's age. Considering the developing CNS during childhood, reductions of a large space-occupying lesion followed by restorations of the structural integrity of the developing brain are very desirable. However, a multi-center cooperative prospective longitudinal study on long-term comparative data of those treated and untreated of neuro-psychological outcome and cyst rupture incidence is needed.

Cranial subdural migrating to lumbar subdural space in a toddler.

Migrated spinal subdural haematoma (sSDH) is a significantly uncommon finding. This case involves a paediatric patient representing after cranial trauma with new abnormal gait and leg pain who was found to have a migrated sSDH. Literature review for reported cases of pathogenesis theories, causes and management was performed and summarised in this report. The authors concluded that new abnormal gait and leg pain in a paediatric patient with previous cranial trauma is an indication for spinal MRI if migrated subdural haematoma is suspected. Non-surgical management is generally tolerated, and steroids can be trialled for radiculopathy if clinically indicated.

Prevalence of Visible Subdural Spaces in Benign Enlargement of Subarachnoid Spaces in Infancy: A Retrospective Analysis Utilizing Magnetic Resonance Imaging.

OBJECTIVE: Benign Enlargement of the Subarachnoid Spaces in Infancy (BESSI) is a common finding during workup for progressive macrocephaly. BESSI has been associated with slightly higher prevalence of subdural (SD) spaces and a risk for developing subdural hematoma. This study utilizes fast brain magnetic resonance imaging (MRI) to investigate the prevalence of visible SD spaces in BESSI. METHODS: A retrospective review was performed for all pediatric patients who underwent brain MRI for macrocephaly. Patients with a diagnosis of BESSI were included in the study. A total of 109 patients met the inclusion criteria. Patient demographics were collected, and images were reviewed for size of subarachnoid, visible SD spaces, and ventricle size. Descriptive and inferential statistics were performed. RESULTS: The average age was 8 ± 4.6 months, 64 (59%) were male, and 55 patients had no previous medical history (50%). Sixty-seven percent of all patients were identified to have visible SD spaces. Eleven patients had confirmed SD hematomas; 1 patient was deemed to have abusive head trauma. Visible SD spaces were associated with younger age (6.9 months). Thirty-one patients with visible SD spaces had follow-up MRI, with complete resolution by 33 months. CONCLUSIONS: BESSI is a self-limiting pathology that has been associated with visible SD spaces and potential risk for SD hemorrhages. We report a high prevalence of visible SD spaces within BESSI through utilization of fast brain MRI. These spaces may contribute to the higher rate of incidental subdural hematoma in this population.

A novel rat model of chronic subdural hematoma: Induction of inflammation and angiogenesis in the subdural space mimicking human-like features of progressively expanding hematoma.

Pathophysiological mechanisms of chronic subdural hematoma (CSDH) involve localized inflammation, angiogenesis, and dysregulated coagulation and fibrinolysis. The scarcity of reproducible and clinically relevant animal models of CSDH hinders further understanding the underlying pathophysiology and improving new treatment strategies. Here, we developed a novel rat model of CSDH using extracellular matrices (Matrigel) and brain microvascular endothelial cell line (bEnd.3 cells). One hundred-microliter of Matrigel-bEnd.3 cell (106 cells per milliliter) mixtures were injected into the virtual subdural space of elderly male Sprague-Dawley rats. This approach for the first time led to a spontaneous and expanding subdural hematoma, encapsulated by internal and external neomembranes, formed as early as 3 d, reached its peak at 7 d, and lasted for more than 14 d, mimicking the progressive hemorrhage observed in patients with CSDH. The external neomembrane and hematoma fluid involved numerous inflammatory cells, fibroblasts, and highly fragile neovessels. Furthermore, a localized pathophysiological process was validated as evidenced by the increased expressions of inflammatory and angiogenic mediators in external neomembrane and hematoma fluid rather than in peripheral blood. Notably, the specific expression profiles of these mediators were closely associated with the dynamic changes in hematoma volume and neurological outcome. In summary, the CSDH model described here replicated the characteristics of human CSDH, and might serve as an ideal translational platform for preclinical studies. Meanwhile, the crucial roles of angiogenesis and inflammation in CSDH formation were reaffirmed.

Further evidence for a continuous flux of bile acids into the brain: trapping of bile acids in subdural hematomas.

Bile acids are known to pass the blood-brain barrier and are present at low concentrations in the brain. In a previous work, it was shown that subdural hematomas are enriched with bile acids and that the levels in such hematomas are higher than in the peripheral circulation. The mechanism behind this enrichment was never elucidated. Bile acids have a high affinity to albumin, and subdural hematomas contain almost as high albumin levels as the peripheral circulation. A subdural hematoma is encapsulated by fibrin which may allow passage of small molecules like bile acids. We hypothesized that bile acids originating from the circulation may be 'trapped' in the albumin in subdural hematomas. In the present work, we measured the conjugated and unconjugated primary bile acids cholic acid and chenodeoxycholic acid in subdural hematomas and in peripheral circulation of 24 patients. In most patients, the levels of both conjugated and free bile acids were higher in the hematomas than in the circulation, but the enrichment of unconjugated bile acids was markedly higher than that of conjugated bile acids. In patients with a known time interval between the primary bleeding and the operation, there was a correlation between this time period and the accumulation of bile acids. This relation was most obvious for unconjugated bile acids. The results are consistent with a continuous flux of bile acids, in particular unconjugated bile acids, across the blood-brain barrier. We discuss the possible physiological importance of bile acid accumulation in subdural hematomas.

Extradural and intradural characteristics of the cervical nerve root anomalies.

The anomalous anatomical arrangement of the cervical spinal nerve roots within the spinal canal can complicate the surgical treatment of several pathologies. This work aimed to reveal intraspinal anatomical anomalies of the extradural and also intradural cervical spinal nerve roots courses. The anatomical study was realised in 43 cadavers with a mean age of 53.7 (32 men and 11 women). After opening the spinal canal and also the dural sac the intradural and extradural anomalies of the cervical spinal nerve roots (bilaterally) were explored and documented. We found completely 49 cases (56.98%) of intraspinal cervical nerve root anomalies. Extradural anomalies were found in 11 cases (12.79%) including atypical spacing, two roots exiting through one neuroforamen, extradural communications, aberrant root. Intradural anomalies observed in 28 cases (32.56%) comprised: communications between the dorsal roots and ventral roots separately or together and the multiple communications. Other anomalies (10 cases, 11.63%) included various types of atypical spacing of the roots and their asymmetry. All the results are differentiated according to the plexus type (pre-, postfixed, normotyped). This study describes intraspinal (extradural and intradural) anatomical anomalies of the cervical spinal nerve root courses. Knowledge of these variabilities should help to prevent the failure of several medical procedures.

Trigeminal Schwannomas in Middle Fossa Could Breach into Subdural Space: Report of 4 Cases and Review of Literature.

OBJECTIVE: The objectives of this study were to report 4 cases diagnosed with trigeminal schwannomas (TS), among whom tumor in epidural space of middle fossa broke through dura mater into subdural space, and to analyze the potential reason for recurrence of TS in middle fossa after surgical removal by endoscopic endonasal approach (EEA) or interdural approach. METHODS: The information of 4 patients diagnosed with TS who were surgically treated was retrospectively analyzed and the selection of approaches, surgical strategies, and potential reason for recurrence after middle fossa TS removal by EEA and interdural approach were discussed. RESULTS: During last 10 years, 43 patients with TS received surgical treatment at Xuan Wu Hospital of Capital Medical University, among whom 1 patient with TS extending from middle fossa to infratemporal fossa was first treated by EEA, then the tumor recurred and the patient underwent a second operation via a frontotemporal subdural approach. During the second operation, we found part of tumor had broken through the dura mater into subdural space. Moreover, this phenomenon was detected in another 3 patients with middle-posterior fossa TS. CONCLUSIONS: TS in middle fossa has been widely believed to be totally located at epidural space, whereas we found that it could occasionally breach into subdural space and accept blood supply from the pial artery. We believe this could be the potential reason for recurrence after tumor resection by EEA and interdural approach.

Melioidosis with a subdural collection - a case report.

BACKGROUND: Melioidosis is an infection caused by Burkholderia pseudomallei, which is more prevalent in the tropics and leads to significant morbidity and mortality. It characteristically produces widespread caseous lesions and abscesses, and can present with varied clinical manifestations. Melioidosis involving the central nervous system is uncommon. CASE PRESENTATION: A 42-year-old Sri Lankan male with type 2 diabetes presented with a febrile illness of 6 days with headache and constitutional symptoms. Clinical examination was unremarkable. Four days later, he developed focal seizures involving the left leg and numbness of the left side. Initial laboratory investigations were suggestive of a bacterial infection. Blood culture was reported as positive for a Pseudomonas species, which was resistant to gentamicin. Contrast enhanced CT and MRI scans of the brain showed a subdural collection in the right fronto-temporo-parietal region with possible abscess formation. Melioidosis antibody testing using indirect hemagglutination method was reactive with a titre more than 1/10,240. He was treated with intravenous meropenem and oral co-trimoxazole for 8 weeks (Intensive phase). The subdural collection was managed conservatively, and seizures were treated with oral antiepileptics. At 7 weeks, follow-up contrast enhanced MRI showed improvement of the subdural collection, and inflammatory markers had normalized. He was discharged after 8 weeks, and treated with oral co-trimoxazole and doxycycline for 6 months (eradication phase). At 6 months follow-up, the patient is asymptomatic. CONCLUSIONS: Cerebral melioidosis is an unusual presentation of melioidosis where the diagnosis can be easily missed. Knowledge of the protean manifestations of melioidosis is of paramount importance in order to detect and treat this potentially fatal infection appropriately, especially in tropical countries where the disease is endemic.

The depth of catheter in chronic subdural haematoma: does it matter?

Objective: To investigate the appropriate depth of drainage catheter in the patients with chronic subdural haematoma (CSDH). Methods: We retrospectively analysed the data of 190 patients with CSDH undergoing single parietal burr-hole evacuation and drainage. Results: According to the depth of catheter (DC), 190 patients were divided into three groups: shallow group (DC <4.3 cm), middle group (DC 4.3 ~ 5.4 cm) and deep group (DC > 5.4 cm). During postdischarge 6 months, two, six and nine patients had recurrences in shallow, middle and deep groups, respectively. The recurrence rate in shallow or middle group was significantly lower than that in deep group. No significant difference in preoperative haematoma volume (PHV) was observed in three groups. While the residual subdural space (RSS) in shallow group was significantly smaller than those in the other two groups. The duration of drainage in shallow, middle and deep groups increased successively, and the differences were statistically significant. The total drainage volume (TDV) in shallow group showed no significant difference when compared with the other two groups. Conclusion: The depth of catheter may affect the outcome of CSDH. Inserting drainage catheter shallowly might be a preferred choice in patients with CSDH undergoing burr-hole evacuation and drainage.

Investigation of subdural electrode displacement in invasive epilepsy surgery workup using neuronavigation and intraoperative MRI.

OBJECTIVES: One of the main obstacles of electrode implantation in epilepsy surgery is the electrode shift between implantation and the day of explantation. We evaluated this possible electrode displacement using intraoperative MRI (iopMRI) data and CT/MRI reconstruction. METHODS: Thirteen patients (nine female, four male, median age 26 ± 9.4 years) suffering from drug-resistant epilepsy were examined. After implantation, the position of subdural electrodes was evaluated by 3.0 T-MRI and thin-slice CCT for 3D reconstruction. Localization of electrodes was performed with the volume-rendering technique. Post-implantation and pre-explantation 1.5 T-iopMRI scans were coregistered with the 3D reconstructions to determine the extent of electrode dislocation. RESULTS: Intraoperative MRI at the time of explantation revealed a relevant electrode shift in one patient (8%) of 10 mm. Median electrode displacement was 1.7 ± 2.6 mm with a coregistration error of 1.9 ± 0.7 mm. The median accuracy of the neuronavigation system was 2.2 ± 0.9 mm. Six of twelve patients undergoing resective surgery were seizure free (Engel class 1A, median follow-up 37.5 ± 11.8 months). CONCLUSION: Comparison of pre-explantation and post-implantation iopMRI scans with CT/MRI data using the volume-rendering technique resulted in an accurate placement of electrodes. In one patient with a considerable electrode dislocation, the surgical approach and extent was changed due to the detected electrode shift. ABBREVIATIONS: ECoG: electrocorticography; EZ: epileptogenic zone; iEEG: invasive EEG; iopMRI: intraoperative MRI; MEG: magnetoencephalography; PET: positron emission tomography; SPECT: single photon emission computed tomography; 3D: three-dimensional.

The Pathogenesis of Subacute Subdural Hematoma: A Report of 3 Cases and Literature Review.

OBJECTIVE: To discuss the pathologic mechanism of subacute subdural hematoma (sASDH). METHODS: Three typical cases of sASDH were reported, and related literature in Chinese published in the past 15 years was reviewed. RESULTS: Intervals from onset of acute subdural hematoma to surgery or symptom deterioration resulting in sASDH were 12.5-15.5 days (mean 14.1 days). Delayed liquefaction of hematoma clots occurred in all 3 reported cases. One patient achieved good curative effect after administration of dexamethasone, and another patient relapsed owing to poor drainage after evacuation of hematoma. CONCLUSIONS: The conversion of acute subdural hematoma to sASDH is an inflammatory reaction process with very regular in time, and it is speculated that the pathologic mechanism may be a delayed hypersensitivity reaction. Antigen released during the liquefaction process of blood clot, with subdural neomembrane cells as antigen-presenting cells, is presented to the T lymphocytes released from the capillaries in the neomembrane and forms sensitized T lymphocytes. When the subsequent antigen is released from the blood clots with a delayed liquefaction and is exposed to sensitized T lymphocytes, the delayed hypersensitivity process occurs.

Reorganized neural activation in motor cortex following subdural fluid collection: an fMRI and DTI study.

We report a patient with a cavernous malformation involving the right lentiform nucleus. Pre-surgical planning included fMRI localization of language, motor, and sensory processing, and DTI of white matter tracts. fMRI results revealed no activation near the planned resection zone. However, post-surgery the patient developed a subdural fluid collection, which applied pressure to the primary motor cortex (M1). Follow-up scans revealed that motor activation had shifted due to pressure, and then shifted to a new location after the fluid collection subsided. This case report suggests that long-term neural reorganization can occur in response to short term compression in the cortex.

Clinical Characteristics and Outcome in Elderly Patients with Traumatic Brain Injury: For Establishment of Management Strategy.

In recent years, instances of neurotrauma in the elderly have been increasing. This article addresses the clinical characteristics, management strategy, and outcome in elderly patients with traumatic brain injury (TBI). Falls to the ground either from standing or from heights are the most common causes of TBI in the elderly, since both motor and physiological functions are degraded in the elderly. Subdural, contusional and intracerebral hematomas are more common in the elderly than the young as the acute traumatic intracranial lesion. High frequency of those lesions has been proposed to be associated with increased volume of the subdural space resulting from the atrophy of the brain in the elderly. The delayed aggravation of intracranial hematomas has been also explained by such anatomical and physiological changes present in the elderly. Delayed hyperemia/hyperperfusion may also be a characteristic of the elderly TBI, although its mechanisms are not fully understood. In addition, widely used pre-injury anticoagulant and antiplatelet therapies may be associated with delayed aggravation, making the management difficult for elderly TBI. It is an urgent issue to establish preventions and treatments for elderly TBI, since its outcome has been remained poor for more than 40 years.

Rosai-Dorfman disease of the subdural spine with a long segment lesion: A case report and literature review.

Rosai-Dorfman disease (RDD) or sinus histiocytosis with massive lymphadenopathy is a rare benign disorder usually characterized by massive painless cervical lymphadenopathy and systemic manifestations. Extranodal involvement, especially spinal involvement, is extremely rare. We report a 41-year-old man who presented with only intermittent dorsodynia. His condition was diagnosed as non-specific inflammatory disease on the basis of preoperative puncture biopsy results. We performed total surgical resection. Histopathological findings showed distinctive emperipolesis and immunohistochemistry results were positive for cluster of differentiation CD68 and S100 and negative for CD1a. A good prognosis was confirmed at the 3-month follow-up visit. This is the first case of RDD of the subdural spine with such a long segment lesion. There is still no consensus regarding appropriate therapy for this type of RDD and the preoperative diagnosis remains challenging. The unusual presentation of our case serves as a reference when diagnosing and treating RDD.

Primary Melanotic Schwannoma with Typical Histology.

We present a case of a 17-year male with a soft tissue density spreading from the neural foramina (T3) of the spinal cord and involving the right upper thoracic cavity. We managed the patient through surgical intervention and resected the complete tumor. Gross definition and microscopic findings of the resected tissue revealed the definitive diagnosis of melanotic schwannoma. The histological characteristics in this case were very specific and harbour an important diagnostic clue for this rare disease. Malignant melanoma was ruled out on the basis of histological findings. The patient recovered completely and was healthy on one-year follow-up.

The effectiveness of microsurgical fenestration for middle fossa arachnoid cysts in children.

OBJECTIVE: Although middle fossa arachnoid cysts (MFACs) are common, the optimal surgical treatment for these lesions remains controversial. In this study, we present our experiences of treating MFACs by microsurgical fenestration and evaluate its effectiveness. METHODS: We performed retrospective review of 28 patients who underwent microsurgical fenestration for MFACs between May 2003 and December 2014. We reviewed patient characteristics and treatment outcomes including age, sex, symptoms, complicating hydrocephalus, Gallasi classification, change in cyst size after surgery, complicating subdural hygroma, symptom resolution, regrowth of the cyst, and reoperation (including additional CSF diversion). RESULTS: Twenty-eight MFACs in 28 patients were investigated. The average age at the time of surgery was 61.6 months. The average follow-up duration was 53.5 months. After surgery, 19 (90.5 %) of 21 patients with symptomatic MFACs experienced improvements. The cysts decreased in size in all cases (100 %, 28/28) and disappeared in three cases (11 %, 3/28). None of the cases experienced regrowth of the cyst. Subdural hygroma was identified in 23 cases (82.1 %) at the immediate postoperative period. Hygroma was asymptomatic in all cases but one. Hygroma disappeared in 19 cases (83 %) and decreased in size in three cases (13 %) in the long term. Only one case (4 %) required an additional subdural-peritoneal shunt. The rate of CSF diversion after the fenestration was significantly higher in patients with preoperative ventricular dilation (p = 0.0002). CONCLUSION: Microsurgical fenestration for pediatric MFACs was considered to be safe and effective. Although subdural hygroma developed in significant number of patients at the immediate postoperative period, it was mostly asymptomatic and disappeared or decreased in size in the long term.

Use of Spongostan™ for Prevention of Cranial Subdural Adhesions Following Craniotomy in an Experimental Rabbit Model.

AIM: Spongostan™ is a sterile, water-insoluble, porcine gelatin absorbable sponge, which is widely used as a hemostatic material. The aim of this study is to test the anti-fibrotic capacity of Spongostan™, using a craniotomy model in an experimental rabbit model. MATERIAL AND METHODS: Eighteen rabbits were divided into two groups: Each group consisted of 9 rabbits, duratomy plus Spongostan™ (group 1), and duratomy without Spongostan™ (group 2). Right parietal bone was removed via trephine and low speed drill and dura was opened. On the group 1 rabbits, an appropriate piece of Spongostan™ was meticulously placed under dural layer. On group 2 rabbits, same procedures were repeated without Spongostan™. Histological sections were taken from each group and evaluated for degree of fibrosis and collagen fibers. RESULTS: There was marked increase in number of fibroblasts and collagen fibers in group 2 rabbits, however most of the rabbits in Spongostan™ group demonstrate scarce histopathological findings for fibrosis. CONCLUSION: We conclude that an appropriately placed subdural Spongostan™ over cerebral tissue may prevent postoperative surgical adhesions after neurosurgical operations.