Deciphering the pH-dependent oligomerization of aspartate semialdehyde dehydrogenase from Wolbachia endosymbiont of Brugia malayi: An in vitro and in silico approaches.

The enzyme aspartate semialdehyde dehydrogenase (ASDH) plays a pivotal role in the amino acid biosynthesis pathway, making it an attractive target for the development of new antimicrobial drugs due to its absence in humans. This study aims to investigate the presence of ASDH in the filarial parasite Wolbachia endosymbiont of Brugia malayi (WBm) using both in vitro and in silico approaches. The size exclusion chromatography (SEC) and Native-PAGE analysis demonstrate that WBm-ASDH undergoes pH-dependent oligomerization and dimerization. To gain a deeper understanding of this phenomenon, the modelled monomer and dimer structures were subjected to pH-dependent dynamics simulations in various conditions. The results reveal that residues Val240, Gln161, Thr159, Tyr160, and Trp316 form strong hydrogen bond contacts in the intersurface area to maintain the structure in the dimeric form. Furthermore, the binding of NADP+ induces conformational changes, leading to an open or closed conformation in the structure. Importantly, the binding of NADP+ does not disturb either the dimerization or oligomerization of the protein, a finding confirmed through both in vitro and in silico analysis. These findings shed light on the structural characteristics of WBm-ASDH and offer valuable insights for the development of new inhibitors specific to WBm, thereby contributing to the development of potential therapies for filarial parasitic infections.

Aneurysmal Subdural Hematoma: A Systematic Review.

BACKGROUND: Aneurysmal subdural hematoma (aSDH) is a rare complication of aneurysm rupture, affecting between 0.5 and 7.9% of patients with aneurysmal subarachnoid hemorrhage (aSAH). The clinical presentation, course, and outcomes of these patients are largely unknown. OBJECTIVE: This study aims to systematically review the literature to evaluate the demographics, clinical presentation, aneurysm location, treatment options, and outcomes of patients with aSDH with and without aSAH. METHODS: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, we conducted a systematic review of three databases (PubMed, EMBASE, and Google Scholar). From identified reports, we extracted data on patients' demographics, clinical presentation, imaging findings, surgical interventions, and clinical outcomes. We compared clinical outcomes, need for surgical treatment, and aneurysm location between patients with aSDH with and without concurrent aSAH using χ2 and Fisher's exact tests. We used simple and multivariable logistic regression models to further examine the association between the presence of aSAH and surgical treatment with clinical outcomes. RESULTS: We identified 112 articles with a total of 270 patients (70% women, mean age 52.8 [± 15.5] years). The most common aneurysm locations were the middle cerebral artery, followed by the posterior communicating artery, and the internal carotid artery. Patients with isolated aSDH fully recovered more frequently than those with concomitant aSAH (38% vs. 6%). The presence of aSAH increased the odds of unfavorable outcome (odds ratio [OR] 2.68, 95% confidence interval [CI] 1.34-5.37). Surgical treatment was inversely associated with unfavorable outcome in the univariable (OR 0.48, 95% CI 0.28-0.84) but not in the multivariable analysis (OR 0.76, 95% CI 0.35-1.66). CONCLUSION: aSDH occurs infrequently. Simultaneous presence of both aSDH and aSAH from an aneurysmal source is associated with poor outcomes. Surgical treatment is associated with lower rates of unfavorable outcomes including death and severe disability.

The Characteristics of Withdrawal or Withholding of Life-Sustaining Treatment in Severe Traumatic Brain Injury: A Single Japanese Institutional Study.

Objectives: There is little evidence on the factors influencing the decision to withdraw or continue life-sustaining treatment in the setting of severe traumatic brain injury in Japanese institutions. We investigated the factors associated with the withdrawal or withholding of life-sustaining treatment (WLST) for severe traumatic brain injury at a single Japanese institution. Methods: A total of 161 patients with severe traumatic brain injury were retrospectively reviewed. Patient characteristics and injury types were compared between patients with and without the WLST. Results: Of the 161 patients, 87 (54%) died and 52 (32%) decided to undergo WLST. In 98% of the WLST cases, the decision was made within 24 h of admission. The mean duration between WLST and death was 2 days. The predicted probabilities for mortality and unfavorable outcomes were highest in patients with WLST within 24 h. Patients with WLST were older and had a higher frequency of falls on the ground, ischemic heart disease, and acute subdural hemorrhage than those without WLST. Conclusions: The decisions of almost all WLST cases were made within 24 h of admission for severe traumatic brain injury in a Japanese institution because of Japanese patients' religious and cultural backgrounds.

Predictive Factors of Outcomes in Acute Subdural Hematoma Evacuation.

OBJECTIVE: This comparative cross-sectional study was conducted in the Departments of Trauma and Neurosurgery, Ayub Teaching Hospital, Abbottabad, Pakistan from September 2021 to February 2022 to study predictive factors of outcomes in acute subdural hematoma evacuation. METHODOLOGY: A total of 101 patients with confirmed diagnosis of acute subdural hematoma (ASDH) who underwent surgical evacuation by consultant neurosurgeon were included in the study. A detailed clinical proforma was designed to document all the clinical and demographic details of these patients at the time of admission. Glasgow Coma Scale outcome score (GOS) was used to assess the outcome of patients after the surgery. Sociodemographic and clinical parameters were associated with outcome of surgery in our study participants. RESULTS: Out of 101 patients, 55 (54.5%) were males and 46 (45.5%) were females. Mean age was 43.66±19.66 years with 7.39 as mean Glasgow Coma Scale (GCS) at presentation. Road traffic accident (RTA) 62 (61.4%) was most frequent mechanism of injury followed by fall from height (19.8%) and history of assault (13.9%). In our study, 59 patients had poor outcomes while 42 had good outcomes. Elder age, low GCS at presentation, and use of oral anticoagulant were associated with poor outcomes while pupillary reaction had no effect on the outcome after application of test of significance. CONCLUSION: More than half of the patients managed with surgical evacuation for acute subdural hematoma as per guidelines at our neurosurgical unit had poor outcomes according to Glasgow Coma Scale. In this study, advancing age (>60 years), low GCS score at presentation, and use of oral anticoagulation therapy emerged as significant risk factors for poor outcomes in participants. Pupillary reaction had no effect on outcomes as per this study but this needs further evaluation in future studies.

Age effects on the mechanical behavior of human cerebral bridging veins.

BACKGROUND: It is well established that the probability of occurrence of acute subdural hematomas in traumatic situations increases with age, since the main cause of such hematomas is the mechanical failure of cerebral blood vessels known as bridging veins. This research aims to determine whether there is an effect of age on the mechanical properties of these cerebral vessels, because previous reported studies were conflicting. METHODS: This study used mechanical tests blue of cerebral bridging veins from post-mortem human subjects. In particular, a series of in vitro tensile tests were performed on a balanced sample of bridging veins from different human subjects. FINDINGS: The mechanical parameters measured from the tests were analyzed by means of regression analysis looking for age related effects. The results show that there is a significant effect on both the ultimate strength, maximum stress and strain that the specimens can withstand. The quantitative analysis shows reductions of nearly 50% in ultimate stress, and almost 35% in ultimate strain. INTERPRETATION: Mechanical deterioration of the mechanical strength of cerebral blood vessels seems to be a major factor involved in the increase of frequency of acute subdural hematoma in elderly people in a wide range of life-threatening traumatic situations.

Does the Timing of the Surgery Have a Major Role in Influencing the Outcome in Elders with Acute Subdural Hematomas?

BACKGROUND: The incidence of traumatic acute subdural hematomas (ASDH) in the elderly is increasing. Despite surgical evacuation, these patients have poor survival and low rate of functional outcome, and surgical timing plays no clear role as a predictor. We investigated whether the timing of surgery had a major role in influencing the outcome in these patients. METHODS: We retrospectively retrieved clinical and radiological data of all patients ≥70 years operated on for post-traumatic ASDH in a 3 year period in five Italian hospitals. Patients were divided into three surgical timing groups from hospital arrival: ultra-early (within 6 h); early (6-24 h); and delayed (after 24 h). Outcome was measured at discharge using two endpoints: survival (alive/dead) and functional outcome at the Glasgow Outcome Scale (GOS). Univariate and multivariate predictor models were constructed. RESULTS: We included 136 patients. About 33% died as a result of the consequences of ASDH and among the survivors, only 24% were in good functional outcome at discharge. Surgical timing groups appeared different according to presenting the Glasgow Outcome Scale (GCS), which was on average lower in the ultra-early surgery group, and radiological findings, which appeared worse in the same group. Delayed surgery was more frequent in patients with subacute clinical deterioration. Surgical timing appeared to be neither associated with survival nor with functional outcome, also after stratification for preoperative GCS. Preoperative midline shift was the strongest outcome predictor. CONCLUSIONS: An earlier surgery was offered to patients with worse clinical-radiological findings. Additionally, after stratification for GCS, it was not associated with better outcome. Among the radiological markers, preoperative midline shift was the strongest outcome predictor.

A multicentre retrospective cohort study on health-related quality of life after traumatic acute subdural haematoma: does cranial laterality affect long-term recovery?

BACKGROUND: Traumatic acute subdural haematoma is a debilitating condition. Laterality intuitively influences management and outcome. However, in contrast to stroke, this research area is rarely studied. The aim is to investigate whether the hemisphere location of the ASDH influences patient outcome. METHODS: For this multicentre observational retrospective cohort study, patients were considered eligible when they were treated by a neurosurgeon for traumatic brain injury between 2008 and 2012, were > 16 years of age, had sustained brain injury with direct presentation to the emergency room and showed a hyperdense, crescent shaped lesion on the computed tomography scan. Patients were followed for a duration of 3-9 months post-trauma for functional outcome and 2-6 years for health-related quality of life. Main outcomes and measures included mortality, Glasgow Outcome Scale and the Quality of Life after Brain Injury score. The hypothesis was formulated after data collection. RESULTS: Of the 187 patients included, 90 had a left-sided ASDH and 97 had a right-sided haematoma. Both groups were comparable at baseline and with respect to the executed treatment. Furthermore, both groups showed no significant difference in mortality and Glasgow Outcome Scale score. Health-related quality of life, assessed 59 months (IQR 43-66) post-injury, was higher for patients with a right-sided haematoma (Quality of Life after Brain Injury score: 80 vs 61, P = 0.07). CONCLUSIONS: This study suggests patients with a right-sided acute subdural haematoma have a better long-term health-related quality of life compared to patients with a left-sided acute subdural haematoma.

Cerebral Blood Flow Disorder in Acute Subdural Hematoma and Acute Intraoperative Brain Bulge.

Context: Acute subdural hematoma (ASDH) has a high incidence and high mortality. During surgery for ASDH, brain tissue sometimes rapidly swells and protrudes into the bone window during or after removal of the hematoma. This phenomenon, known as acute intraoperative brain bulge, progresses rapidly and can cause ischemic necrosis of brain tissue or even mortality. The mechanism of this phenomenon remains unclear. Objective: To investigate the changes in cerebral surface blood flow during ASDH and acute intraoperative brain bulge in rats. Methods: Adult male Sprague-Dawley rats were selected to establish an ASDH model, and acute intraoperative brain bulge was induced by late-onset intracranial hematoma. The changes in cerebral surface blood flow during ASDH and acute intraoperative brain bulge were observed with a laser speckle imaging system, and intracranial pressure (ICP) was monitored. Results: ICP in rats increased significantly after ASDH (P < 0.05). The blood perfusion rate (BPR) values of the superior sagittal sinus, collateral vein and artery decreased significantly in rats with subdural hematomas (P < 0.05). There was no significant difference between the preoperative and 90-min postoperative BPR values of rats. ICP was significantly increased in rats with acute intraoperative brain bulge (P < 0.05) and decreased significantly after the removal of delayed hematomas (P < 0.05). The BPR of the superior sagittal sinus, collateral vein and artery decreased significantly during brain bulge (P < 0.05). After the removal of delayed hematomas, BPR increased significantly, but it remained significantly different from the values measured before brain bulge (P < 0.05). Conclusion: ASDH may cause not only high intracranial pressure but also cerebral blood circulation disorders. Brain bulge resulting from late-onset intracranial hematoma may aggravate these circulation disorders. If the cause of brain bulge in a given patient is late-onset intracranial hematoma, clinicians should promptly perform surgery to remove the hematoma and relieve circulation disorders, thus preventing more serious complications.

Hinge and floating decompressive craniotomy for infantile acute subdural hematoma: technical note.

Cranioplasty complications after decompressive craniectomy (DC) in infants are not fully recognized. We aimed to devise and assess the efficacy of a hinge and floating DC (HFDC) technique for treating infantile acute subdural hematoma. Five infants, aged 2-20 months, were included. Intracranial pressure was controlled below 20 mmHg, no additional surgery was required, and there was no incidence of surgical site infection or bone graft resorption.

Litigation risks despite guideline adherence for acute spinal cord injury: time is spine.

OBJECTIVE: Current guidelines do not specify timing for management of acute spinal cord injury (aSCI) due to lack of high-quality evidence supporting specific intervals for intervention. Randomized prospective trials may be unethical. Nonetheless, physicians have been sued for delays in diagnosis and intervention. METHODS: The authors reviewed both the medical literature supporting the guidelines and the legal cases reported in the Westlaw and Lexis Advance databases from 1972 to 2018 resulting in awards or settlements, to identify whether surgeons are vulnerable to litigation despite the existence of guidelines not mandating specific timing of care. RESULTS: Timing of intervention was related to claims in 59 (36%) of 163 cases involving SCI. All 22 trauma cases identified cited timing of intervention, sometimes related to delayed diagnosis, as a reason for the lawsuit. The mean award of 10 cases in which the plaintiffs' awards were disclosed was $4,294,384. In the majority of cases, award amounts were not disclosed. CONCLUSIONS: Because conduct of a prospective, randomized trial to investigate surgical timing of intervention for aSCI may not be achievable, evidence-based guidelines will be unlikely to mandate specific timing. Nonetheless, surgeons who unreasonably delay intervention for aSCI may be at risk for litigation due to treatment delay. This is increasingly likely in an environment where "complete" SCI is difficult to verify. SCI may at some point be recognized as a surgical emergency, as brain injury generally is, despite a lack of prospective randomized trials supporting this implementation, challenging the feasibility of the US trauma infrastructure to provide care for these patients.

Acute subdural hematoma in the elderly: outcome analysis in a retrospective multicentric series of 213 patients.

OBJECTIVE: The objective of this study was to analyze the risk factors associated with the outcome of acute subdural hematoma (ASDH) in elderly patients treated either surgically or nonsurgically. METHODS: The authors performed a retrospective multicentric analysis of clinical and radiological data on patients aged ≥ 70 years who had been consecutively admitted to the neurosurgical department of 5 Italian hospitals for the management of posttraumatic ASDH in a 3-year period. Outcome was measured according to the Glasgow Outcome Scale (GOS) at discharge and at 6 months' follow-up. A GOS score of 1-3 was defined as a poor outcome and a GOS score of 4-5 as a good outcome. Univariate and multivariate statistics were used to determine outcome predictors in the entire study population and in the surgical group. RESULTS: Overall, 213 patients were admitted during the 3-year study period. Outcome was poor in 135 (63%) patients, as 65 (31%) died during their admission, 33 (15%) were in a vegetative state, and 37 (17%) had severe disability at discharge. Surgical patients had worse clinical and radiological findings on arrival or during their admission than the patients undergoing conservative treatment. Surgery was performed in 147 (69%) patients, and 114 (78%) of them had a poor outcome. In stratifying patients by their Glasgow Coma Scale (GCS) score, the authors found that surgery reduced mortality but not the frequency of a poor outcome in the patients with a moderate to severe GCS score. The GCS score and midline shift were the most significant predictors of outcome. Antiplatelet drugs were associated with better outcomes; however, patients taking such medications had a better GCS score and better radiological findings, which could have influenced the former finding. Patients with fixed pupils never had a good outcome. Age and Charlson Comorbidity Index were not associated with outcome. CONCLUSIONS: Traumatic ASDH in the elderly is a severe condition, with the GCS score and midline shift the stronger outcome predictors, while age per se and comorbidities were not associated with outcome. Antithrombotic drugs do not seem to negatively influence pretreatment status or posttreatment outcome. Surgery was performed in patients with a worse clinical and radiological status, reducing the rate of death but not the frequency of a poor outcome.

Evaluation of brain-skull interface modelling approaches on the prediction of acute subdural hematoma in the elderly.

Acute subdural hematoma (ASDH) in the elderly is currently a matter of concern due to the growing number of the aging population and their higher incident rate compared to the younger adults. Computational head models that can replicate this age-related injury pattern are valuable tools to help addressing this concern. Although a biofidelic brain-skull interface modelling strategy is essential for accurate ASDH prediction, approaches with different simplifications have been used in existing head models to simulate the interaction between the brain and skull with their ASDH predictability unknown. Thus, the current communication evaluates the applicability of different brain-skull interface modelling approaches for ASDH prediction associated with age-related brain atrophy. Four representative approaches are selected by simulating cerebrospinal fluid (CSF) as Lagrangian-represented solid and Arbitrary Lagrangian-Eulerian (ALE) represented fluid, each with or without tangential sliding aginst the brain. The chosen approaches are implemented in three models with various degrees of atrophied brain, which are subsequently exposed to an experimentally measured loading known to cause ASDH. The results show, only when simulating the CSF as ALE elements with sliding interface against the brain, a relatively higher ASDH risk characterized by increased cortical relative motion and BV strain peaks are predicted by the atrophied model without causing excessive mesh distortion in the CSF elements. The results of this study provide guidance for brain-skull interface modelling, particularly for the prediction of ASDH in different age groups.

A case of paroxysmal homonymous hemianopsia: Uncommon presentation of nonconvulsive status epilepticus.

Paroxysmal homonymous hemianopsia (HH) is uncommon presentation of epilepsy. We demonstrate a rare case of paroxysmal HH that was diagnosed by magnetic resonance (MR) arterial spin-labeling (ASL). A 82-year-old woman presented with abrupt onset of isolated visual field abnormality without convulsive epilepsy at 16 days after a traumatic head injury. Diffusion weighted and MR-ASL obtained on admission revealed hyperintensity and hyperperfusion in the right temporo-occipital cortex. Nonconvulsive status epilepticus was suspected. The patient was treated with oral levetiracetam and the symptoms resolved in 3 days. Paroxysmal HH should be considered in patients who present with simple partial epilepsy, and MR-ASL imaging may assist in the differential diagnosis of these patients.

Computed tomography findings after head injury preceding chronic subdural hematoma.

OBJECTIVE: Head CT is sometimes performed immediately after minor head injury; however, which cases develop into chronic subdural hematoma (CSDH) remains unclear. Here, the authors retrospectively reviewed the rare cases of CSDH treated surgically in which early head CT had been performed after the initial head trauma. METHODS: A total of 172 patients (133 male and 39 female, median age 76 years) underwent surgery for CSDH at Gunma University Hospital between April 2010 and December 2017. Among these patients were 23 who had visited Gunma University Hospital or a nearby hospital and had undergone head CT within 7 days after the initial head trauma. Characteristics of the initial head CT were examined to identify indicators of subsequent CSDH. RESULTS: Among the 23 CSDH cases (17 male and 6 female, median age 80 years), CT scans were obtained on the day of the initial injury (day 0) in 19 cases (25 sides) and 1-7 days after injury in 12 cases (19 sides); scans were obtained during both periods in 8 cases (12 sides), so that a total of 44 sides were examined. These CT scans were divided into two groups according to when they were obtained; cases in which scans were taken during both periods were included in both groups. Head CT performed on the day of injury showed normal findings in 5 (20%) of 25 sides, thin subdural effusion (SDE) ≤ 6 mm in 16 (64%) of 25 sides, thick SDE > 6 mm in 3 (12%) of 25 sides, and acute subdural hematoma (ASDH) in 1 (4%) of 25 sides. CT from 1-7 days after trauma showed thick SDE in 9 (47%) of 19 sides, thin SDE in 8 (42%) of 19 sides, and ASDH in 2 (11%) of 19 sides. A high-density line in the lateral direction (onion skin-like) was found between the skull and the brain in 9 (35%) of 26 sides with SDE on initial CT 0-7 days after the injury. CONCLUSIONS: ASDH was not a common cause of CSDH. Head CT at the time of trauma that precedes CSDH often showed SDE. Such SDE that precedes CSDH was often close to the detection limit of CT immediately after the injury but became more apparent from the day after the injury.

Effect of preoperative antiplatelet or anticoagulation therapy on hemorrhagic complications in patients with traumatic brain injury undergoing craniotomy or craniectomy.

OBJECTIVE: Traumatic brain injury (TBI) is common among the elderly, often treated with antiplatelet (AP) or anticoagulation (AC) therapy, creating new challenges in neurosurgery. In contrast to elective craniotomy, in which AP/AC therapy is mostly discontinued, in TBI usually no delay in treatment can be afforded. The aim of this study was to analyze the effect of AP/AC therapy on postoperative bleeding after craniotomy/craniectomy in TBI. METHODS: Postoperative bleeding rates in patients treated with AP/AC therapy (blood thinner group) and in those without AP/AC therapy (control group) were retrospectively compared. Furthermore, univariate and multivariate analyses were conducted to identify risk factors for postoperative bleeding. Lastly, a proportional Cox regression analysis comparing postoperative bleeding events within 14 days in both groups was performed. RESULTS: Of 143 consecutive patients undergoing craniotomy/craniectomy for TBI between 2012 and 2017, 47 (32.9%) were under AP/AC treatment. No significant difference for bleeding events was observed in univariate (40.4% blood thinner group vs 36.5% control group; p = 0.71) or Cox proportional regression analysis (log rank χ2 = 0.29, p = 0.59). Patients with postoperative bleeding showed a significantly higher mortality rate (p = 0.035). In the univariate analysis, hemispheric lesion, acute subdural hematoma, hematological disease, greater extent of midline shift, and pupillary difference were significantly associated with a higher risk of postoperative bleeding. However, in the multivariate regression analysis none of these factors showed a significant association with postoperative bleeding. CONCLUSIONS: Patients treated with AP/AC therapy undergoing craniotomy/craniectomy due to TBI do not appear to have increased rates of postoperative bleeding. Once postoperative bleeding occurs, mortality rates rise significantly.

In-hospital mortality and length of hospital stay with craniotomy versus craniectomy for acute subdural hemorrhage: a multicenter, propensity score-matched analysis.

OBJECTIVE: The optimal surgical treatment for acute subdural hemorrhage (ASDH) remains controversial. The purpose of this study was to compare outcomes in patients who underwent craniotomy with those in patients who underwent decompressive craniectomy for the treatment of ASDH. METHODS: Using the Japan Trauma Data Bank, a nationwide trauma registry, the authors identified patients aged ≥ 18 years with ASDH who underwent surgical evacuation after blunt head trauma between 2004 and 2015. Logistic regression analysis was used to estimate a propensity score to predict decompressive craniectomy use. They then used propensity score-matched analysis to compare patients who underwent craniotomy with those who underwent decompressive craniectomy. To identify the potential benefits and disadvantages of decompressive craniectomy among different subgroups, they estimated the interactions between treatment and the subgroups using logistic regression analysis. RESULTS: Of 236,698 patients who were registered in the database, 1788 were eligible for propensity score-matched analysis. The final analysis included 514 patients who underwent craniotomy and 514 patients who underwent decompressive craniectomy. The in-hospital mortality did not differ significantly between the groups (41.6% for the craniotomy group vs 39.1% for the decompressive craniectomy group; absolute difference -2.5%; 95% CI -8.5% to 3.5%). The length of hospital stay was significantly longer in patients who underwent decompressive craniectomy (median 23 days [IQR 4-52 days] vs 30 days [IQR 7-60 days], p = 0.005). Subgroup analyses demonstrated qualitative interactions between decompressive craniectomy and the patient subgroups, suggesting that patients who were more severely injured (Glasgow Coma Scale score < 9 and probability of survival < 0.64) and those involved in high-energy injuries may be good candidates for decompressive craniectomy. CONCLUSIONS: The results of this study showed that overall, decompressive craniectomy did not appear to be superior to craniotomy in ASDH treatment in terms of in-hospital mortality. In contrast, there were significant differences in the effectiveness of decompressive craniectomy between the subgroups. Thus, future studies should prioritize the identification of a subset of patients who will possibly benefit from the performance of each of the procedures.

Biomechanics of Acute Subdural Hematoma in the Elderly: A Fluid-Structure Interaction Study.

Acute subdural hematoma (ASDH) caused by bridging vein (BV) rupture is a frequent and lethal brain injury, especially in the elderly. Brain atrophy has been hypothesized to be a primary pathogenesis associated with the increased risk of ASDH in the elderly. Although decades of biomechanical endeavors have been made to elucidate the potential mechanisms, a thorough explanation for this hypothesis appears lacking. Therefore, a recently improved finite element head model, in which the brain-skull interface was modeled using a fluid-structure interaction (FSI) approach with special treatment of the cerebrospinal fluid as arbitrary Lagrangian-Eulerian fluid formulation, is used to partially address this understanding gap. Models with various degrees of atrophied brains and thereby different subarachnoid thicknesses are generated and subsequently exposed to experimentally determined loadings known to cause ASDH or not. The results show significant increases in the cortical relative motion and BV strain in the atrophied brain, which consequently exacerbates the ASDH risk in the elderly. Results of this study are suggested to be considered when developing age-adapted protecting strategies for the elderly in the future.

Double-crescent sign as a predictor of chronic subdural hematoma recurrence following burr-hole surgery.

OBJECTIVE: Subdural hygroma has been reported as a causative factor in the development of a chronic subdural hematoma (CSDH) following a head trauma and/or neurosurgical procedure. In some CSDH cases, the presence of a 2-layered space delineated by the same or similar density of CSF surrounded by a superficial, residual hematoma is seen on CT imaging after evacuation of the hematoma. The aims of the present study were to test the hypothesis that the double-crescent sign (DCS), a unique imaging finding described here, is associated with the postoperative recurrence of CSDH, and to investigate other factors that are related to CSDH recurrence. METHODS: The authors retrospectively analyzed data from 278 consecutive patients who underwent single burr-hole surgery for CSDH between April 2012 and March 2017. The DCS was defined as a postoperative CT finding, characterized by the following 2 layers: a superficial layer demonstrating residual hematoma after evacuation of the CSDH, and a deep layer between the brain's surface and the residual hematoma, depicted as a low-density space. Correlation of the recurrence of CSDH with the DCS was evaluated by multivariate logistic regression modeling. The authors also investigated other classic predictive factors including age, sex, past history of head injury, hematoma laterality, anticoagulant and antiplatelet therapy administration, preoperative hematoma volume, postoperative residual hematoma volume, and postoperative brain reexpansion rate. RESULTS: A total of 277 patients (320 hemispheres) were reviewed. Fifty (18.1%) of the 277 patients experienced recurrence of CSDH within 3 months of surgery. CSDH recurred within 3 months of surgery in 32 of the 104 hemispheres with a positive DCS. Multivariate logistic analyses revealed that the presence of the DCS (OR 3.36, 95% CI 1.72-6.57, p < 0.001), large postoperative residual hematoma volume (OR 2.88, 95% CI 1.24-6.71, p = 0.014), anticoagulant therapy (OR 3.03, 95% CI 1.02-9.01, p = 0.046), and bilateral hematoma (OR 3.57, 95% CI 1.79-7.13, p < 0.001) were significant, independent predictors of CSDH recurrence. CONCLUSIONS: In this study, the authors report that detection of the DCS within 7 days of surgery is an independent predictive factor for CSDH recurrence. They therefore advocate that clinicians should carefully monitor patients for postoperative DCS and subsequent CSDH recurrence.

Association of time to craniectomy with survival in patients with severe combat-related brain injury.

OBJECTIVEIn combat and austere environments, evacuation to a location with neurosurgery capability is challenging. A planning target in terms of time to neurosurgery is paramount to inform prepositioning of neurosurgical and transport resources to support a population at risk. This study sought to examine the association of wait time to craniectomy with mortality in patients with severe combat-related brain injury who received decompressive craniectomy.METHODSPatients with combat-related brain injury sustained between 2005 and 2015 who underwent craniectomy at deployed surgical facilities were identified from the Department of Defense Trauma Registry and Joint Trauma System Role 2 Registry. Eligible patients survived transport to a hospital capable of diagnosing the need for craniectomy and performing surgery. Statistical analyses included unadjusted comparisons of postoperative mortality by elapsed time from injury to start of craniectomy, and Cox proportional hazards modeling adjusting for potential confounders. Time from injury to craniectomy was divided into quintiles, and explored in Cox models as a binary variable comparing early versus delayed craniectomy with cutoffs determined by the maximum value of each quintile (quintile 1 vs 2-5, quintiles 1-2 vs 3-5, etc.). Covariates included location of the facility at which the craniectomy was performed (limited-resource role 2 facility vs neurosurgically capable role 3 facility), use of head CT scan, US military status, age, head Abbreviated Injury Scale score, Injury Severity Score, and injury year. To reduce immortal time bias, time from injury to hospital arrival was included as a covariate, entry into the survival analysis cohort was defined as hospital arrival time, and early versus delayed craniectomy was modeled as a time-dependent covariate. Follow-up for survival ended at death, hospital discharge, or hospital day 16, whichever occurred first.RESULTSOf 486 patients identified as having undergone craniectomy, 213 (44%) had complete date/time values. Unadjusted postoperative mortality was 23% for quintile 1 (n = 43, time from injury to start of craniectomy 30-152 minutes); 7% for quintile 2 (n = 42, 154-210 minutes); 7% for quintile 3 (n = 43, 212-320 minutes); 19% for quintile 4 (n = 42, 325-639 minutes); and 14% for quintile 5 (n = 43, 665-3885 minutes). In Cox models adjusted for potential confounders and immortal time bias, postoperative mortality was significantly lower when time to craniectomy was within 5.33 hours of injury (quintiles 1-3) relative to longer delays (quintiles 4-5), with an adjusted hazard ratio of 0.28, 95% CI 0.10-0.76 (p = 0.012).CONCLUSIONSPostoperative mortality was significantly lower when craniectomy was initiated within 5.33 hours of injury. Further research to optimize craniectomy timing and mitigate delays is needed. Functional outcomes should also be evaluated.