Radiographical presentations of inadvertent subdural placement of an epidural catheter for successful labor analgesia: A case report.

RATIONALE: Lumbar epidural analgesia is the gold standard for labor pain control. However, misplacement of epidural catheters into the subdural space may inadvertently happen. Unrecognized subdural administration of local anesthetics could result in serious consequences, including high spinal and brainstem blocks. This case report describes a case where subdural epidural catheter placement was recognized early but labor pain was adequately managed by dosage titration of subdural analgesia. PATIENT CONCERNS: This case report describes a 29-year-old primiparous pregnant woman who was admitted to our obstetric unit for labor induction at the gestational age of 38 weeks. An epidural catheter was inserted via the L2-3 intervertebral space using the standard loss of resistance to air technique. DIAGNOSES: The parturient experienced weakness in the lower extremities and numbness in the upper extremities within 15 minutes after administration of 5 mL of 2% v/v lidocaine as a loading dose and systolic blood pressure also dropped by 25%. INTERVENTIONS: The dose regimen (a mixture of 0.1% ropivacaine and 4 µg/mL fentanyl) for patient-controlled analgesia was given with bolus doses of 0.1 mL per demand and lockout intervals of 20 minutes. The analgesic effects were adequately maintained below the T8 dermatome for more than 12 hours without hypotensive episodes or obvious signs of neurological deficits. Computed tomographic myelography was performed by instillation of a nonionic iodinated contrast medium via the epidural catheter on postpartum day 2 for imaging confirmation of catheter placement in the extradural space. LESSONS: Early recognition that epidural catheters for neuraxial analgesia have been inserted into the subdural space is important for the prevention of high spinal blocks. Subdural analgesia could still be achieved by careful clinical assessment and titration of low analgesic doses. This report also presents important and clear serial computed tomographic images of catheter placement in the thoracic-lumbar subdural spaces and the extent of volume spread in the subdural space following administration of contrast medium.

MRI Findings after Recent Image-Guided Lumbar Puncture: The Rate of Dural Enhancement and Subdural Collections.

BACKGROUND AND PURPOSE: The rate of abnormal intracranial MR imaging findings including subdural collections and dural enhancement after recent lumbar puncture is not known. The purpose of our study was to examine the intracranial MR imaging findings after recent image-guided lumbar puncture. MATERIALS AND METHODS: Patients who underwent contrast-enhanced MR imaging of the brain within 7 days of a CT-guided lumbar puncture between January 2014 and April 2021 were included. Contrast-enhanced MR images were reviewed for diffuse dural enhancement, morphologic findings of brain sag, dural venous sinus distension, and subdural collections. RESULTS: Of the 160 patients who met the inclusion criteria, only 6 patients (3.9%) had new diffuse dural enhancement, though none had dural enhancement when the MR imaging was within 2 days of lumbar puncture. All 6 patients with dural enhancement had small, concurrent subdural collections. Two additional patients had subdural collections, for a total of 5.2% of our population. CONCLUSIONS: Our study is the first to examine intracranial MR imaging after recent lumbar puncture and has 2 key findings: First, 5.2% of patients had small, bilateral subdural collections after recent lumbar puncture, suggesting that asymptomatic subdural collections after recent lumbar puncture are not atypical and do not require further work-up. Additionally, when MR imaging was performed within 2 days of lumbar puncture, none of our patients had diffuse dural enhancement. This argues against the commonly held practice of performing MR imaging before lumbar puncture to avoid findings of dural enhancement, and should not delay diagnostic work-up.

Subdural Air Increases Postoperative Recurrence of Chronic Subdural Hematoma After Initial Burr-hole Surgery Only in the Very Elderly: A Pilot Study.

OBJECTIVE: Numerous randomized controlled trials have identified risk factors increasing the postoperative recurrence of chronic subdural hematoma (CSDH). Postoperative subdural air is frequently seen on computed tomography imaging. The aim of this study was to test the hypothesis that the presence of significant subdural air postoperatively is related to recurrence of CSDH after burr-hole surgery. METHODS: A single-center, retrospective pilot study analyzed patients 20 years and older who underwent initial burr-hole surgery for CSDH. Data from 452 consecutive patients were included. Significant subdural air was considered to be present when the subdural air area was >4 cm2 in 1 axial CT slice. Correlation of the recurrence and the number of slices that included significant subdural air at postoperative day (POD) 1 was evaluated. Other classic predictive factors were also investigated. RESULTS: The recurrence rate was 13.0% in these 452 cases. After univariate analyses of all the variables, multivariate analysis for age, sex, cerebral infarction, number of slices containing significant subdural air, and maximum depth of the subdural space confirmed that older age and male sex were independent risk factors for recurrence (P = 0.032 and 0.047, respectively). After subdividing cases into older (≥75 years of age)/younger and male/female subgroups, the presence of significant subdural air at POD 1 was identified as an independent risk factor for recurrence in older adults (P = 0.025, OR = 1.12). CONCLUSIONS: Although this is a pilot study, it is suggested that significant postoperative subdural air increases recurrence after initial burr-hole surgery for CSDH in adults ≥75 years of age.

Subdural false twins: concomitant appearance of subdural haematoma and spontaneous subdural empyema.

A 55-year-old man was taken to the emergency department due to right arm weakness for the past 3 days and fever (39.5°C). There was no impaired consciousness, no history of trauma and meningeal signs were absent on physical examination. Blood analysis and inflammatory markers were not evocative of a systemic infection. A cranial CT scan was requested, revealing hypodense bilateral hemispheric subdural collections, suggestive of chronic subdural haematomas. He was submitted to surgical drainage by burr holes, which confirmed the chronic subdural collection on the left side. Unexpectedly, after dural opening on the right side, a subdural purulent collection was found, which was later confirmed as an empyema due to Escherichia coli infection. A second surgical drainage was performed by craniotomy due to recurrence of the right subdural collection. Spontaneously appearing subdural empyemas due to E. coli are extremely rare and their treatment is not always straightforward. The reported case is an example of an apparently straightforward and frequent pathology that turned out to be a challenging case, requiring a multidisciplinary approach.

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.

Subdural extravasation of crystalloids and blood products through a scalp peripheral intravenous catheter into the subdural space of a neonate on veno-arterial extracorporeal membrane oxygenation.

We describe a rare and devastating complication of a malpositioned scalp peripheral intravenous catheter (PIV) that resulted in subdural extravasation of infused fluids and midline shift in a critically ill neonate who required extracorporeal membrane oxygenation (ECMO). Recognition of increased intracranial pressure was hindered by the hemodynamic changes of being on ECMO and only identified by routine surveillance ultrasonography. Awareness of this complication may lead providers to seek alternate sites for vascular access in such patients, and encourage closer monitoring for this complication when an alternate site is unavailable.

Surprisingly Successful Subdural Spinal Cord Stimulation: A Case Report.

Accidental subdural placement of spinal cord stimulator electrodes is a rare event believed to produce unreliable results, necessitating immediate removal. We report a case of a 59-year-old man with failed back surgery syndrome previously controlled with a spinal cord stimulator, who underwent spinal cord stimulator revision during which 1 lead was inadvertently advanced into the subdural space. Modified stimulation parameters achieved excellent, persistent pain relief, representing the first case of successful long-term subdural spinal cord stimulation.

Subdural Pneumocephalus Aspiration Reduces Recurrence of Chronic Subdural Hematoma.

BACKGROUND: Chronic subdural hematoma (cSDH) is a common neurosurgical condition, with symptoms ranging from headaches to coma. Operative evacuation is the treatment of choice. Subdural reaccumulation leading to reoperation is a vexing postoperative complication. OBJECTIVE: To present a novel technique for intraoperative aspiration of pneumocephalus via a subdural drain following SDH evacuation as a method of reducing potential subdural space and promoting cerebral expansion, thereby decreasing SDH recurrence. METHODS: In this retrospective study, 15 patients who underwent operative evacuation of cSDH between 2008 and 2015 were assessed. Six patients underwent a small craniotomy with intraoperative pneumocephalus aspiration. These patients were matched by age, gender, and anticoagulation status to 9 patients who underwent evacuation of SDH without pneumocephalus aspiration. Quantitative volumetric analysis was performed on the preoperative, postoperative, and 1-mo follow-up computed tomography scan to assess the subdural volume. RESULTS: In the immediate postoperative period, there was no difference in the percentage of residual subdural fluid between the aspiration and control groups (0.291 vs 0.251; P = 1.00). There was a decrease in amount of pneumocephalus present when the aspiration technique was applied (0.182 vs 0.386; P = .041). At 1-mo follow-up, there was a decrease in the residual cSDH volume between the aspiration and the control groups (28.7 mL vs 60.8 mL; P = .011). The long-term evacuation rate was greater in the aspiration group (75.4% vs 51.6%; P = .015). CONCLUSION: Intraoperative aspiration of cSDH cavity is a safe technique that may enhance cerebral expansion and reduce likelihood of cSDH recurrence.

Tumoral Mimics of Subdural Hematomas: Case Report and Review of Diagnostic and Management Strategies in Primary B-Cell Lymphoma of the Subdural Space.

BACKGROUND: Subdural lymphomas are a rare subtype of primary central nervous system lymphomas that can radiographically mimic epidural blood and pose a diagnostic challenge. They can complicate treatment if not preemptively identified. METHODS: We present a case report of a subdural lymphoma that mimicked a compressive subdural hematoma, and we review the PubMed database for similar cases. RESULTS: A 77-year-old woman presented with a transient left facial droop and what appeared to be a subdural hematoma on computed tomography scan. The patient underwent surgery, during which grossly abnormal solid epicortical adherent tissue was noted instead of the expected appearance of a subdural hematoma. An intraoperative biopsy was suggestive of lymphoma, and the surgery was converted to a craniectomy. Pathology confirmed the diagnosis of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue. The patient underwent radiotherapy with no complications or recurrence. Magnetic resonance imaging demonstrated complete resolution of the mass at 3 months after treatment, at which time the patient underwent a synthetic cranioplasty. Seven case reports of primary dural lymphomas mimicking subdural blood were found, with variable pathologic subclassifications. CONCLUSIONS: Although rare, a primary dural lymphoma can be mistaken for a subdural hematoma on computed tomography scan. The most common subtype is low-grade extranodal marginal zone lymphomas. It is important to keep these diseases in the differential diagnosis, especially when there is incongruence between imaging and the clinical picture, as earlier detection correlates to a stronger therapeutic response.

Craniotomy Size for Subdural Grid Electrode Placement in Invasive Epilepsy Diagnostics.

BACKGROUND: Traditionally, for subdural grid electrode placement, large craniotomies have been applied for optimal electrode placement. Nowadays, microneurosurgeons prefer patient-tailored minimally invasive approaches. Absolute figures on craniotomy size have never been reported. To elucidate the craniotomy size necessary for successful diagnostics, we reviewed our single-center experience. METHODS: Within 3 years, 58 patients with focal epilepsies underwent subdural grid implantation using patient-tailored navigation-based craniotomies. Craniotomy sizes were measured retrospectively. The number of electrodes and the feasibility of the resection were evaluated. Sixteen historical patients served as controls. RESULTS: In all 58 patients, subdural electrodes were implanted as planned through tailored craniotomies. The mean craniotomy size was 28 ± 15 cm2 via which 55 ± 16 electrodes were implanted. In temporal lobe diagnostics, even smaller craniotomies were applied (21 ± 11 cm2). Craniotomies were significantly smaller than in historical controls (65 ± 23 cm2, p < 0.05), while the mean number of electrodes was comparable. The mean operation time was shorter and complications were reduced in tailored craniotomies. CONCLUSION: Craniotomy size for subdural electrode implantation is controversial. Some surgeons favor large craniotomies, while others strive for minimally invasive approaches. For the first time, we measured the actual craniotomy size for subdural grid electrode implantation. All procedures were straightforward. We therefore advocate for patient-tailored minimally invasive approaches - standard in modern microneurosurgery - in epilepsy surgery as well.

Subperiosteal vs Subdural Drain After Burr-Hole Drainage of Chronic Subdural Hematoma: A Randomized Clinical Trial (cSDH-Drain-Trial).

BACKGROUND: The use of a subdural drain (SDD) after burr-hole drainage of chronic subdural hematoma (cSDH) reduces recurrence at 6 mo. Subperiosteal drains (SPDs) are considered safer, since they are not positioned in direct contact to cortical structures, bridging veins, or hematoma membranes. OBJECTIVE: To investigate whether the recurrence rate after insertion of a SPD is noninferior to the insertion of a more commonly used SDD. METHODS: Multicenter, prospective, randomized, controlled, noninferiority trial analyzing patients undergoing burr-hole drainage for cSDH aged 18 yr and older. After hematoma evacuation, patients were randomly assigned to receive either a SDD (SDD-group) or a SPD (SPD-group). The primary endpoint was recurrence indicating a reoperation within 12 mo, with a noninferiority margin of 3.5%. Secondary outcomes included clinical and radiological outcome, morbidity and mortality rates, and length of stay. RESULTS: Of 220 randomized patients, all were included in the final analysis (120 SPD and 100 SDD). Recurrence rate was lower in the SPD group (8.33%, 95% confidence interval [CI] 4.28-14.72) than in the SDD group (12.00%, 95% CI 6.66-19.73), with the treatment difference (3.67%, 95% CI -12.6-5.3) not meeting predefined noninferiority criteria. The SPD group showed significantly lower rates of surgical infections (P = .0406) and iatrogenic morbidity through drain placement (P = .0184). Length of stay and mortality rates were comparable in both groups. CONCLUSION: Although the noninferiority criteria were not met, SPD insertion led to lower recurrence rates, fewer surgical infections, and lower drain misplacement rates. These findings suggest that SPD may be warranted in routine clinical practice.

Assessing Spinal Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension With a Scoring System Based on Brain Magnetic Resonance Imaging Findings.

Importance: Various signs may be observed on brain magnetic resonance imaging (MRI) in patients with spontaneous intracranial hypotension (SIH). However, the lack of a classification system integrating these findings limits decision making in clinical practice. Objective: To develop a probability score based on the most relevant brain MRI findings to assess the likelihood of an underlying spinal cerebrospinal fluid (CSF) leak in patients with SIH. Design, Setting, and Participants: This case-control study in consecutive patients investigated for SIH was conducted at a single hospital department from February 2013 to October 2017. Patients with missing brain MRI data were excluded. Three blinded readers retrospectively reviewed the brain MRI scans of patients with SIH and a spinal CSF leak, patients with orthostatic headache without a CSF leak, and healthy control participants, evaluating 9 quantitative and 7 qualitative signs. A predictive diagnostic score based on multivariable backward logistic regression analysis was then derived. Its performance was validated internally in a prospective cohort of patients who had clinical suspicion for SIH. Main Outcomes and Measures: Likelihood of a spinal CSF leak based on the proposed diagnostic score. Results: A total of 152 participants (101 female [66.4%]; mean [SD] age, 46.1 [14.3] years) were studied. These included 56 with SIH and a spinal CSF leak, 16 with orthostatic headache without a CSF leak, 60 control participants, and 20 patients in the validation cohort. Six imaging findings were included in the final scoring system. Three were weighted as major (2 points each): pachymeningeal enhancement, engorgement of venous sinus, and effacement of the suprasellar cistern of 4.0 mm or less. Three were considered minor (1 point each): subdural fluid collection, effacement of the prepontine cistern of 5.0 mm or less, and mamillopontine distance of 6.5 mm or less. Patients were classified into groups at low, intermediate, or high probability of having a spinal CSF leak, with total scores of 2 points or fewer, 3 to 4 points, and 5 points or more, respectively, on a scale of 9 points. The discriminatory ability of the proposed score could be demonstrated in the validation cohort. Conclusions and Relevance: This 3-tier predictive scoring system is based on the 6 most relevant brain MRI findings and allows assessment of the likelihood (low, intermediate, or high) of a positive spinal imaging result in patients with SIH. It may be useful in identifying patients with SIH who are leak positive and in whom further invasive myelographic examinations are warranted before considering targeted therapy.

Quantification of Subdural Electrode Shift Between Initial Implantation, Postimplantation Computed Tomography, and Subsequent Resection Surgery.

BACKGROUND: Subdural electrodes are often implanted for localization of epileptic regions. Postoperative computed tomography (CT) is typically acquired to locate electrode positions for planning any subsequent surgical resection. Electrodes are assumed to remain stationary between CT acquisition and resection surgery. OBJECTIVE: To quantify subdural electrode shift that occurred between the times of implantation (Crani 1), postoperative CT acquisition, and resection surgery (Crani 2). METHODS: Twenty-three patients in this case series undergoing subdural electrode implantation were evaluated. Preoperative magnetic resonance and postoperative CT were acquired and coregistered, and electrode positions were extracted from CT. Intraoperative positions of electrodes and the cortical surface were digitized with a coregistered stereovision system. Movement of the exposed cortical surface was also tracked, and change in electrode positions was calculated relative to both the skull and the cortical surface. RESULTS: In the 23 cases, average shift of electrode positions was 8.0 ± 3.3 mm between Crani 1 and CT, 9.2 ± 3.7 mm between CT and Crani 2, and 6.2 ± 3.0 mm between Crani 1 and Crani 2. The average cortical shift was 4.7 ± 1.4 mm with 2.9 ± 1.0 mm in the lateral direction. The average shift of electrode positions relative to the cortical surface between Crani 1 and Crani 2 was 5.5 ± 3.7 mm. CONCLUSION: The results show that electrodes shifted laterally not only relative to the skull, but also relative to the cortical surface, thereby displacing the electrodes from their initial placement on the cortex. This has significant clinical implications for resection based upon seizure activity and functional mapping derived from intracranial electrodes.

Invasive EEG-electrodes in presurgical evaluation of epilepsies: Systematic analysis of implantation-, video-EEG-monitoring- and explantation-related complications, and review of literature.

INTRODUCTION: Stereoelectroencephalography (sEEG) is a diagnostic procedure for patients with refractory focal epilepsies that is performed to localize and define the epileptogenic zone. In contrast to grid electrodes, sEEG electrodes are implanted using minimal invasive operation techniques without large craniotomies. Previous studies provided good evidence that sEEG implantation is a safe and effective procedure; however, complications in asymptomatic patients after explantation may be underreported. The aim of this analysis was to systematically analyze clinical and imaging data following implantation and explantation. RESULTS: We analyzed 18 consecutive patients (mean age: 30.5 years, range: 12-46; 61% female) undergoing invasive presurgical video-EEG monitoring via sEEG electrodes (n = 167 implanted electrodes) over a period of 2.5 years with robot-assisted implantation. There were no neurological deficits reported after implantation or explantation in any of the enrolled patients. Postimplantation imaging showed a minimal subclinical subarachnoid hemorrhage in one patient and further workup revealed a previously unknown factor VII deficiency. No injuries or status epilepticus occurred during video-EEG monitoring. In one patient, a seizure-related asymptomatic cross break of two fixation screws was found and led to revision surgery. Unspecific symptoms like headaches or low-grade fever were present in 10 of 18 (56%) patients during the first days of video-EEG monitoring and were transient. Postexplantation imaging showed asymptomatic and small bleedings close to four electrodes (2.8%). CONCLUSION: Overall, sEEG is a safe and well-tolerated procedure. Systematic imaging after implantation and explantation helps to identify clinically silent complications of sEEG. In the literature, complication rates of up to 4.4% in sEEG and in 49.9% of subdural EEG are reported; however, systematic imaging after explantation was not performed throughout the studies, which may have led to underreporting of associated complications.

Ictal onset patterns of subdural intracranial electroencephalogram in children: How helpful for predicting epilepsy surgery outcome?

AIMS: We aimed to classify ictal onset patterns (IOPs) in pediatric patients undergoing intracranial electroencephalography (IEEG) to guide surgery for refractory epilepsy. We aimed to determine if morphology of IOPs can predict surgical outcome. MATERIALS AND METHODS: We performed a retrospective review of pediatric patients who underwent epilepsy surgery guided by subdural IEEG from 2007 to 2016. IEEG seizures were reviewed by a blinded epileptologist. Data was collected on outcomes. RESULTS: Twenty-three patients with 784 seizures were included. Age at seizure onset was 0.2-11 (mean 4.3, standard deviation 3.2) years. Age at time of IEEG was 4-20 (mean 13.5, standard deviation 4.4) years. Five distinct IOPs were seen at seizure onset: A) Low voltage fast activity (LVFA) with spread to adjacent electrodes (n = 7 patients, 30%), B) Burst of LVFA followed by electrodecrement (n = 12 patients, 52%), C) Burst of rhythmic spike waves (RSW) followed by electrodecrement (n = 9 patients, 39%), D) RSW followed by LVFA (n = 7 patients, 30%), E) Rhythmic spikes alone (n = 10 patients, 43%). Twelve patients (52%) had the same IOP type with all seizures. When the area of the IOP was resected, 14 patients (61%) had Engel I outcomes. Patients who had LVFA seen within their predominant IOP type were more likely to have good surgical outcomes (odds ratio 7.50, 95% confidence interval 1.02-55.0, p = 0.05). Patients who had only one IOP type were more likely to have good outcomes than patients who had multiple IOP types (odds ratio 12.6, 95% confidence interval 1.19-134, p = 0.04). Patients who had LVFA in their predominant IOP type were older than patients who did not have LVFA (mean age 15.0 vs. 9.9 years, p = 0.02). CONCLUSIONS: LVFA at ictal onset and all seizures having the same IOP morphology are associated with increased likelihood of surgical success in children, but LVFA is less common in children who are younger at the time of IEEG.

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.

Subdural Tension on the Brain in Patients with Chronic Subdural Hematoma Is Related to Hemiparesis but Not to Headache or Recurrence.

BACKGROUND: Hemiparesis is a major symptom of chronic subdural hematoma (CSDH). Its severity does not always correlate with hematoma size. The authors analyzed hematoma thickness, pressure, and tension to clarify the mechanism of hemiparesis in CSDH patients. METHODS: A burr-hole surgery was performed on 124 CSDHs in 102 patients. Hematoma thickness and midline shift were measured by computed tomography, and hematoma pressure was measured in surgery. According to Laplace law, tension was calculated as follows: (half the hematoma thickness × hematoma pressure)/2. Student t test and Pearson correlation coefficient (r) were applied in statistical analysis of findings. RESULTS: Motor weakness was identified in 76.5% of our cases. Tension was strongly related to hemiparesis (r = -0.747, P < 0.01), whereas hematoma thickness (r = -0.458, P < 0.01) and pressure (r = -0.596, P < 0.01) were moderately correlated. Mean age of 14 patients (13.7%) with headache was much younger than those without headache (P < 0.01). Stronger midline shift (P < 0.01) and greater ratio of midline shift to hematoma thickness (P < 0.01) were statistically correlated with headache. Recurrence was recognized in 8 patients (7.8%), and stronger midline shift (P < 0.05) and greater ratio of midline shift to hematoma thickness (P < 0.05) were statistically associated with recurrence. CONCLUSIONS: Tension is the most influencing factor to hemiparesis in CSDH patients. This study also elucidates the mechanism for quick recovery from hemiparesis after surgery in that tension on the motor cortex is decreased immediately by drainage.

Solitary subdural osteoma: A case report and literature review.

BACKGROUND: Subdural osteomas are benign neoplasms that are rarely encountered. We report the case of a 64­year­old female patient with a left temporal subdural osteoma. CASE DESCRIPTION: The patient presented with intermittent dizziness that first began two years earlier. Non-contrast computed tomography revealed a densely calcified left temporal extra-axial mass. Magnetic resonance imaging of the lesion revealed signal loss on T1-weighted and T2-weighted images and non-enhancement on Gadolinium enhanced T1-weighted images, and diffusion-weighted and ADC images demonstrated reduced values attributed to calcium-induced signal loss. Histologically, the lesion predominantly consisted of lamellar bone without bone marrow elements. The patient underwent stereotactic magnetic resonance imaging-guided neurosurgical resection and recovered without complication. CONCLUSIONS: Subdural osteomas may not be enhanced on magnetic resonance imaging. Surgical tumourectomy can be considered for symptomatic patients with subdural osteomas.

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.

Delayed intracranial subdural empyema following burr hole drainage: Case series and literature review.

RATIONALE: A subdural empyema (SDE) following burr hole drainage of a chronic subdural hematoma (CSDH) can be difficult to distinguish from a recurrence of the CSDH, especially when imaging data is limited to a computed tomography (CT) scan. PATIENTS CONCERNS: All patients underwent burr hole drainage of the CSDH at first, and the appearance of the SDE occurred within one month. DIAGNOSES: A contrast-enhanced magnetic resonance imaging (MRI) scan, with diffusion-weighted imaging (DWI), revealed both the SDE and diffuse meningitis in all patients. INTERVENTIONS: In Case 1, because the patient was very young, burr hole drainage of the SDE, rather than craniotomy, was performed. However, subsequent craniotomy was required due to recurrence of the SDE. In Cases 2 and 3, an initial craniotomy was performed without burr hole drainage. OUTCOMES: Symptoms improved for all patients, and each was discharged without any neurologic deficits or subsequent recurrence. LESSONS: Neurosurgeons should consider the possibility of infection if recurrence of CSDH occurs within 1 month following drainage of a subdural hematoma. A contrast-enhanced MRI with DWI should be performed to differentiate SDE from CSDH. In addition, surgical evacuation of the empyema via wide craniotomy is preferred to burr hole drainage.