Intraoperative Nerve Stimulation as an Approach for the Surgical Treatment of Genitofemoral Neuralgia.

BACKGROUND Genitofemoral neuralgia is a pain syndrome that involves injury to the genitofemoral nerve and is frequently iatrogenic. We report intraoperative nerve localization using ultrasound, nerve stimulation, and the cremasteric reflex in the surgical treatment of genitofemoral neuralgia. CASE REPORT A 49-year-old man with a history of extracorporeal membrane oxygenation with cannulation sites in bilateral inguinal regions presented with right groin numbness and pain following decannulation. His symptoms corresponded to the distribution of the genitofemoral nerve. He had a Tinel's sign over the midpoint of his inguinal incision. A nerve block resulted in temporary resolution of his symptoms. Due to the presence of a pacemaker, peripheral nerve neuromodulation was contraindicated. He underwent external neurolysis and neurectomy of the right genitofemoral nerve. Following direct stimulation and ultrasound for localization, the nerve was further localized intraoperatively using nerve stimulation with monitoring for the presence of the cremasteric reflex. At his 1-month postoperative visit, his right medial thigh pain had resolved and his right testicular pain 50% improved; his residual pain continued to improve at last evaluation 3 months after surgery. CONCLUSIONS We report the successful use of nerve stimulation and the cremasteric reflex to aid in identification of the genitofemoral nerve intraoperatively for the treatment of genitofemoral neuralgia.

Neutrophil-Lymphocyte ratio is associated with poor clinical outcome after mechanical thrombectomy in stroke in patients with COVID-19.

BACKGROUND: The neutrophil-lymphocyte ratio (NLR) is emerging as an important biomarker of acute physiologic stress in a myriad of medical conditions, and is a confirmed poor prognostic indicator in COVID-19. OBJECTIVE: We sought to describe the role of NLR in predicting poor outcome in COVID-19 patients undergoing mechanical thrombectomy for acute ischemic stroke. METHODS: We analyzed NLR in COVID-19 patients with large vessel occlusion (LVO) strokes enrolled into an international 12-center retrospective study of laboratory-confirmed COVID-19, consecutively admitted between March 1, 2020 and May 1, 2020. Increased NLR was defined as ≥7.2. Logistic regression models were generated. RESULTS: Incidence of LVO stroke was 38/6698 (.57%). Mean age of patients was 62 years (range 27-87), and mortality rate was 30%. Age, sex, and ethnicity were not predictive of mortality. Elevated NLR and poor vessel recanalization (Thrombolysis in Cerebral Infarction (TICI) score of 1 or 2a) synergistically predicted poor outcome (likelihood ratio 11.65, p = .003). Patients with NLR > 7.2 were 6.8 times more likely to die (OR 6.8, CI95% 1.2-38.6, p = .03) and almost 8 times more likely to require prolonged invasive mechanical ventilation (OR 7.8, CI95% 1.2-52.4, p = .03). In a multivariate analysis, NLR > 7.2 predicted poor outcome even when controlling for the effect of low TICI score on poor outcome (NLR p = .043, TICI p = .070). CONCLUSIONS: We show elevated NLR in LVO patients with COVID-19 portends significantly worse outcomes and increased mortality regardless of recanalization status. Severe neuro-inflammatory stress response related to COVID-19 may negate the potential benefits of successful thrombectomy.

Prognostic Significance of Baseline Frailty Status in Traumatic Spinal Cord Injury.

BACKGROUND: Literature evaluating frailty in traumatic spinal cord injury (tSCI) is limited. OBJECTIVE: To evaluate the prognostic significance of baseline frailty status in tSCI. METHODS: Patients with tSCI were identified in the National Inpatient Sample from 2015 to 2018 and stratified according to frailty status, which was quantified using the 11-point modified frailty index (mFI). RESULTS: Among 8825 operatively managed patients with tSCI identified (mean age 57.9 years, 27.6% female), 3125 (35.4%) were robust (mFI = 0), 2530 (28.7%) were prefrail (mFI = 1), 1670 (18.9%) were frail (mFI = 2), and 1500 (17.0%) were severely frail (mFI ≥ 3). One thousand four-hundred forty-five patients (16.4%) were routinely discharged (to home), and 320 (3.6%) died during hospitalization, while 2050 (23.3%) developed a severe complication, and 2175 (24.6%) experienced an extended length of stay. After multivariable analysis adjusting for age, illness severity, trauma burden, and other baseline covariates, frailty (by mFI-11) was independently associated with lower likelihood of routine discharge [adjusted odds ratio (aOR) 0.82, 95% CI 0.77-0.87; P < .001] and development of a severe complication (aOR 1.17, 95% CI 1.12-1.23; P < .001), but not with in-hospital mortality or extended length of stay. Subgroup analysis by age demonstrated robust associations of frailty with routine discharge in advanced age groups (aOR 0.71 in patients 60-80 years and aOR 0.69 in those older than 80 years), which was not present in younger age groups. CONCLUSION: Frailty is an independent predictor of clinical outcomes after tSCI, especially among patients of advanced age. Our large-scale analysis contributes novel insights into limited existing literature on this topic.

Endovascular Thrombectomy for Pediatric Acute Ischemic Stroke.

BACKGROUND: Evidence regarding the utilization and outcomes of endovascular thrombectomy (EVT) for pediatric ischemic stroke is limited, and justification for its use is largely based on extrapolation from clinical benefits observed in adults. METHODS: Weighted discharge data from the National Inpatient Sample were queried to identify pediatric patients with ischemic stroke (<18 years old) during the period of 2010 to 2019. Complex samples statistical methods were used to characterize the profiles and clinical outcomes of EVT-treated patients. Propensity adjustment was performed to address confounding by indication for EVT based on disparities in baseline characteristics between EVT-treated patients and those medically managed. RESULTS: Among 7365 pediatric patients with ischemic stroke identified, 190 (2.6%) were treated with EVT. Utilization significantly increased in the post-EVT clinical trial era (2016-2019; 1.7% versus 4.0%; P<0.001), while the use of decompressive hemicraniectomy decreased (2.8% versus 0.7%; P<0.001). On unadjusted analysis, 105 (55.3%) EVT-treated patients achieved favorable functional outcomes at discharge (home or to acute rehabilitation), while no periprocedural iatrogenic complications or instances of contrast-induced kidney injury were reported. Following propensity adjustment, EVT-treated patients demonstrated higher absolute but nonsignificant rates of favorable functional outcomes in comparison with medically managed patients (55.3% versus 52.8%; P=0.830; adjusted hazard ratio, 1.01 [95% CI, 0.51-2.03]; P=0.972 for unfavorable outcome). Among patients with baseline National Institutes of Health Stroke Scale score >11 (75th percentile of scores in cohort), EVT-treated patients trended toward higher rates of favorable functional outcomes compared with those treated medically only (71.4% versus 55.6%; P=0.146). In a subcohort assessment of EVT-treated patients, those administered preceding thrombolytic therapy (n=79, 41.6%) trended toward higher rates of favorable functional outcomes (63.3% versus 49.5%; P=0.060). CONCLUSIONS: This cross-sectional evaluation of the clinical course and short-term outcomes of pediatric patients with ischemic stroke treated with EVT demonstrates that EVT is likely a safe modality which confers high rates of favorable functional outcomes.

Development of cerebral vasospasm following traumatic intracranial hemorrhage: incidence, risk factors, and clinical outcomes.

OBJECTIVE: Limited evidence exists characterizing the incidence, risk factors, and clinical associations of cerebral vasospasm following traumatic intracranial hemorrhage (tICH) on a large scale. Therefore, the authors sought to use data from a national inpatient registry to investigate these aspects of posttraumatic vasospasm (PTV) to further elucidate potential causes of neurological morbidity and mortality subsequent to the initial insult. METHODS: Weighted discharge data from the National (Nationwide) Inpatient Sample from 2015 to 2018 were queried to identify patients with tICH who underwent diagnostic angiography in the same admission and, subsequently, those who developed angiographically confirmed cerebral vasospasm. Multivariable logistic regression analysis was performed to identify significant associations between clinical covariates and the development of vasospasm, and a tICH vasospasm predictive model (tICH-VPM) was generated based on the effect sizes of these parameters. RESULTS: Among 5880 identified patients with tICH, 375 developed PTV corresponding to an incidence of 6.4%. Multivariable adjusted modeling determined that the following clinical covariates were independently associated with the development of PTV, among others: age (adjusted odds ratio [aOR] 0.98, 95% CI 0.97-0.99; p < 0.001), admission Glasgow Coma Scale score < 9 (aOR 1.80, 95% CI 1.12-2.90; p = 0.015), intraventricular hemorrhage (aOR 6.27, 95% CI 3.49-11.26; p < 0.001), tobacco smoking (aOR 1.36, 95% CI 1.02-1.80; p = 0.035), cocaine use (aOR 3.62, 95% CI 1.97-6.63; p < 0.001), fever (aOR 2.09, 95% CI 1.34-3.27; p = 0.001), and hypokalemia (aOR 1.62, 95% CI 1.26-2.08; p < 0.001). The tICH-VPM achieved moderately high discrimination, with an area under the curve of 0.75 (sensitivity = 0.61 and specificity = 0.81). Development of vasospasm was independently associated with a lower likelihood of routine discharge (aOR 0.60, 95% CI 0.45-0.78; p < 0.001) and an extended hospital length of stay (aOR 3.53, 95% CI 2.78-4.48; p < 0.001), but not with mortality. CONCLUSIONS: This population-based analysis of vasospasm in tICH has identified common clinical risk factors for its development, and has established an independent association between the development of vasospasm and poorer neurological outcomes.

Association of Elevated Body Mass Index with Functional Outcome and Mortality following Acute Ischemic Stroke: The Obesity Paradox Revisited.

BACKGROUND: Previous literature has identified a survival advantage in acute ischemic stroke (AIS) patients with elevated body mass indices (BMIs), a phenomenon termed the "obesity paradox." OBJECTIVE: The aim of this study was to evaluate the independent association between obesity and clinical outcomes following AIS. METHODS: Weighted discharge data from the National Inpatient Sample were queried to identify AIS patients from 2015 to 2018. Multivariable logistic regression and Cox proportional hazards modeling were performed to evaluate associations between obesity (BMI ≥ 30) and clinical endpoints following adjustment for acute stroke severity and comorbidity burden. RESULTS: Among 1,687,805 AIS patients, 216,775 (12.8%) were obese. Compared to nonobese individuals, these patients were younger (64 vs. 72 mean years), had lower baseline NIHSS scores (6.9 vs. 7.9 mean score), and a higher comorbidity burden. Multivariable analysis demonstrated independent associations between obesity and lower likelihood of mortality (adjusted odds ratio [aOR] 0.76, 95% confidence interval [CI]: 0.71, 0.82, p < 0.001; hazard ratio 0.84, 95% CI: 0.73, 0.97, p = 0.015), intracranial hemorrhage (aOR 0.87, 95% CI: 0.82, 0.93, p < 0.001), and routine discharge to home (aOR 0.97, 95% CI: 0.95, 0.99; p = 0.015). Mortality rates between obese and nonobese patients were significantly lower across stroke severity thresholds, but this difference was attenuated among high severity (NIHSS > 20) strokes (21.6% vs. 23.2%, p = 0.358). Further stratification of the cohort into BMI categories demonstrated a "U-shaped" association with mortality (underweight aOR 1.58, 95% CI: 1.39, 1.79; p < 0.001, overweight aOR 0.64, 95% CI: 0.42, 0.99; p = 0.046, obese aOR 0.77, 95% CI: 0.71, 0.83; p < 0.001, severely obese aOR 1.18, 95% CI: 0.74, 1.87; p = 0.485). Sub-cohort assessment of thrombectomy-treated patients demonstrated an independent association of obesity (BMI 30-40) with lower mortality (aOR 0.79, 95% CI: 0.65, 0.96; p = 0.015), but not with routine discharge. CONCLUSION: This cross-sectional analysis demonstrates a lower likelihood of discharge to home as well as in-hospital mortality in obese patients following AIS, suggestive of a protective effect of obesity against mortality but not against all poststroke neurological deficits in the short term which would necessitate placement in acute rehabilitation and long-term care facilities.

Endovascular thrombectomy with and without preceding intravenous thrombolysis for treatment of large vessel anterior circulation stroke: A cross-sectional analysis of 50,000 patients.

INTRODUCTION: The safety and efficacy of intravenous thrombolysis (IVT) before endovascular thrombectomy (EVT) for large vessel occlusion stroke remains a highly contested and unanswered clinical question. We aim to characterize the clinical profile, complications, and discharge disposition of EVT patients treated with and without preceding IVT using a large, nationally-representative sample. METHODS: The National Inpatient Sample was queried from 2015 to 2018 to identify adult patients with anterior circulation stroke treated with EVT with and without preceding IVT. Multivariable logistic regression analysis and propensity-score matching were employed to assess adjusted associations with clinical endpoints and to address confounding by indication for IVT, respectively. RESULTS: Among 48,525 patients identified, 40.7% (n = 19,735) received IVT prior to EVT. On unadjusted analysis, patients treated with IVT bridging therapy experienced higher rates of intracranial hemorrhage (26% vs. 24%, p = 0.003) and routine discharge to home with or without services (33% vs. 27%, p < 0.001), a lower frequency of thromboembolic complications (3% vs. 5%, p < 0.001), and lower rates of extended hospital stays (eLOS) (20% vs. 24%, p < 0.001). Multivariable logistic regression analysis adjusting for demographic and baseline clinical characteristics demonstrated independent associations of IVT bridging therapy with intracranial hemorrhage (aOR 1.28, 95% CI 1.15, 1.43; p < 0.001), thromboembolic complications (aOR 0.66, 95% CI 0.53, 0.83; p < 0.001), routine discharge (aOR 1.27, 95% CI 1.15, 1.40; p < 0.001), and eLOS (aOR 0.76, 95% CI 0.68, 0.85; p < 0.001). Sensitivity testing confirmed these findings. CONCLUSION: Preceding IVT was associated with favorable functional outcomes following endovascular therapy. Prospective randomized clinical trials are warranted for further evaluation.

Comparative associations of baseline frailty status and age with postoperative mortality and duration of hospital stay following metastatic brain tumor resection.

Metastatic brain tumors are the most common intracranial neoplasms diagnosed in the United States. Although baseline frailty status has been validated as a robust predictor of morbidity and mortality across various surgical disciplines, evidence within cranial neurosurgical oncology is limited. Adult metastatic brain tumor patients treated with resection were identified in the National Inpatient Sample during the period of 2015-2018. Frailty was quantified using the 11-point modified frailty index (mFI-11) and its association with clinical endpoints was evaluated through complex samples multivariable logistic regression and receiver operating characteristic (ROC) curve analyses. Among 13,650 metastatic brain tumor patients identified (mean age 62.8 years), 26.8% (n = 3665) were robust (mFI = 0), 31.4% (n = 4660) were pre-frail (mFI = 1), 23.2% (n = 3165) were frail (mFI = 2), and 15.8% (n = 2160) were severely frail (mFI ≥ 3). On univariable assessment, these cohorts stratified by increasing frailty were significantly associated with postoperative complications (13.6%, 15.9%, 23.9%, 26.4%; p < 0.001), mortality (1.2%, 1.4%, 2.7%, 3.2%; p = 0.028), and extended length of stay (eLOS) (15.7%, 22.5%, 28.9%, 37.7%; p < 0.001). Following multivariable logistic regression analysis, frailty (by mFI-11) was independently associated with postoperative mortality (aOR 1.34, 95% CI 1.08, 1.65) and eLOS (aOR 1.26, 95% CI 1.17, 1.37), while increasing age was not associated with these endpoints. ROC curve analysis demonstrated superior discrimination of frailty (by mFI-11) in comparison with age for both mortality (AUC 0.61 vs. 0.58) and eLOS (AUC 0.61 vs. 0.53). Further statistical assessment through propensity score adjustment and decision tree analysis confirmed and extended the findings of the primary analytical models. Frailty may be a more robust predictor of postoperative outcomes in comparison with age following metastatic brain tumor resection.

Nationwide trends in middle meningeal artery embolization for treatment of chronic subdural hematoma: A population-based analysis of utilization and short-term outcomes.

Middle meningeal artery (MMA) embolization represents a promising novel treatment modality for chronic subdural hematoma (cSDH), yet utilization and efficacy data are limited. This study evaluates the utilization and short-term outcomes of MMA embolization for cSDH treatment in a large national inpatient registry. cSDH patients treated with MMA embolization and/or surgical evacuation (craniotomy/burr hole drainage) were identified using the National Inpatient Sample (NIS) during 2012-2018 period. Temporal trends, complications, and discharge disposition were evaluated, and propensity score matching was implemented for adjusted comparisons and to mitigate confounding by indication. Among 60,045 cSDH patients identified, 390 (0.6%) underwent MMA embolization. Embolized patients presented more with high acute illness severity subclasses in comparison with surgically evacuated patients (53% vs. 34%, p = 0.004) yet did not experience any procedure-related hemorrhagic or ischemic complications. Although discharge disposition did not differ from those surgically managed, embolized patients had longer mean hospital stays (13 vs. 8 days, p = 0.023) and accrued greater hospital charges (p < 0.001). Following propensity adjustment, length of stay and charges remained greater in the embolization cohort, yet rates of routine discharge increased appreciably (40% vs. 30%, p = 0.141) relative to surgically treated cSDH patients. The utilization of embolization increased exponentially after 2015, reaching an apex in 2018 (3.7% of treated cSDH). This population-based national assessment demonstrates exponential increases in utilization of MMA embolization for cSDH treatment in recent years. Embolized patients had uncomplicated clinical courses and similar discharge dispositions as surgical evacuation patients. Large-scale prospective trials are warranted to further assess the efficacy of this modality.

Pipeline embolization of ruptured, previously coiled cerebral aneurysms: Case series and considerations for management.

PURPOSE: Aneurysmal recurrence represents a significant drawback of endovascular coiling, particularly in aneurysms that have previously ruptured. Given the high recurrence rate of coiled aneurysms and particularly the risk of posttreatment rupture in previously ruptured aneurysms that have been treated by coiling, the question of how best to treat ruptured aneurysms that recur postcoiling remains. MATERIALS AND METHODS: We conducted a retrospective analysis of twenty patients who underwent pipeline embolization of previously ruptured, coiled cerebral aneurysms. RESULTS: Pipeline embolization device (PED) treatment resulted in complete aneurysmal occlusion in 10 patients (62.5%) at first angiographic follow-up, and 11 patients (68.75%) at last follow-up. No PED-related complications were encountered and there were no peri-procedural or postprocedural hemorrhages, or symptomatic ischemic events following flow diversion. CONCLUSIONS: PED as a second-line treatment is a safe and effective modality for achieving aneurysmal occlusion in recurrent, previously ruptured, primarily coiled aneurysms. Additionally, a staged coil-to-PED approach may be considered for the management of acutely ruptured aneurysms to achieve aneurysmal obliteration in an effort to mitigate recurrence, and reduce the amount of postprocedural studies.

Incidence of Neo-Intimal Hyperplasia in Anterior Circulation Aneurysms Following Pipeline Flow Diversion.

INTRODUCTION: Flow diversion of the distal anterior circulation cerebral vasculature may be used for management of wide necked aneurysms not amenable to other endovascular approaches. Follow-up angiography sometimes demonstrates neo-intimal hyperplasia within or adjacent to the stent, however there is limited evidence in the literature examining the incidence in MCA and ACA aneurysms. We present our experience with flow diversion of the distal vasculature and evaluate the incidence of neo-intimal hyperplasia. MATERIALS AND METHODS: Retrospective review of patients who underwent Pipeline embolization device (PED) treatment for ruptured and unruptured anterior circulation aneurysms. RESULTS: A total of 251 anterior circulation aneurysms were treated by pipeline flow diversion, of which 175 were ICA aneurysms, 14 were ACA aneurysms and 18 were MCA aneurysms. 6-month follow-up angiography was available in 207 patients. The incidence of neo-intimal hyperplasia was 15.9%, 21.4%, and 61.1% in ICA, ACA, and MCA aneurysms, respectively. MCA-territory aneurysms developed neo-intimal hyperplasia at a significantly higher rate than aneurysms in other vessel territories. Rates of aneurysmal occlusion did not significantly differ from those patients who did not exhibit intimal hyperplasia on follow-up angiography. CONCLUSION: In our experience, flow diversion of distal wide-necked MCA and ACA aneurysms is a safe and effective treatment strategy. The presence of neo-intimal hyperplasia at 6-month angiography is typically clinically asymptomatic. Given the statistically higher rate of neo-intimal hyperplasia in MCA aneurysms at 6-month angiography, we propose delaying initial follow-up angiography to 12-months and maintaining dual antiplatelet therapy during that time.

Decompressive craniectomy with scalp expansion graft using a temporary synthetic skin substitute in the pediatric population: case series and review of the literature.

INTRODUCTION: The use of decompressive craniectomy in children is controversial and often reserved for patients with refractory intracranial hypertension. Following decompression, skin closure in select cases can be challenging due to brain herniation and swelling through the craniectomy defect. In these cases, partial cortical debridement is sometimes performed. METHODS: We describe two cases in which a synthetic skin substitute was used to facilitate a tension-free closure, rather than performing a partial lobectomy. RESULTS: At 6-month follow-up, both patients are at preoperative cognitive baseline, with some residual hemiparesis. DISCUSSION: We believe that use of a synthetic skin substitute for skin closure after decompression is a suitable option for closure of traumatic scalp wounds and may contribute to improved functional outcome in patients with severe intraoperative brain swelling.

An unusual case of hemophagocytic lymphohistiocytosis diagnosed by spinal nerve root biopsy.

Hemophagocytic lymphohistiocytosis (HLH) is a rare disease process characterized by aberrant immune system activation and an exaggerated inflammatory response. Establishing the diagnosis may be challenging and is achieved by satisfying a number of clinical criteria, in addition to demonstrating tissue hemophagocytosis. This syndrome is rapidly fatal if prompt diagnosis and treatment are not achieved. The authors present the case of a 17-year-old male patient with CNS HLH involving both the brain and spinal cord, highlighting the variable CNS manifestations in pediatric patients with HLH and the challenges that accompany establishing diagnosis.

The role of 5-aminolevulinic acid in spinal tumor surgery: a review.

PURPOSE: Primary intradural spinal neoplasms account for a small proportion of central nervous system tumors. The primary treatment for these tumors consists of maximal safe resection and preservation of neurologic function. Gross total resection, which is associated with the lowest rate of tumor recurrence and longer progression-free survival for most histologies, can be difficult to achieve. Currently, the use of 5-aminolevulinc acid (5-ALA) which takes advantage of Protoporphyrin IX (PpIX) fluorescence, is a well-established technique for improving resection of malignant cerebral gliomas. This technique is being increasingly applied to other cerebral neoplasms, and multiple studies have attempted to evaluate the utility of 5-ALA-aided resection of spinal neoplasms. METHODS: The authors reviewed the existing literature on the use of 5-ALA and PpIX fluorescence as an aid to resection of primary and secondary spinal neoplasms by searching the PUBMED and EMBASE database for records up to March 2018. Data was abstracted from all studies describing spinal neurosurgical uses in the English language. RESULTS: In the reviewed studies, the most useful fluorescence was observed in meningiomas, ependymomas, drop metastases from cerebral gliomas, and hemangiopericytomas of the spine, which is consistent with applications in cerebral neoplasms. CONCLUSIONS: The available literature is significantly limited by a lack of standardized methods for measurement and quantification of 5-ALA fluorescence. The results of the reviewed studies should guide future development of rational trial protocols for the use of 5-ALA guided resection in spinal neoplasms.

Molecular Sequence of Events and Signaling Pathways in Cerebral Metastases.

Brain metastases are the leading cause of morbidity and mortality among cancer patients, and are reported to occur in about 40% of cancer patients with metastatic disease in the United States of America. Primary tumor cells appear to detach from the parent tumor site, migrate, survive and pass through the blood brain barrier in order to establish cerebral metastases. This complex process involves distinct molecular and genetic mechanisms that mediate metastasis from these primary organs to the brain. Furthermore, an interaction between the invading cells and cerebral milieu is shown to promote this process as well. Here, we review the mechanisms by which primary cancer cells metastasize to the brain via a mechanism called epithelial-to-mesenchymal transition, as well as the involvement of certain microRNA and genetic aberrations implicated in cerebral metastases from the lung, breast, skin, kidney and colon. While the mechanisms governing the development of brain metastases remain a major hindrance in treatment, understanding and identification of the aforementioned molecular pathways may allow for improved management and discovery of novel therapeutic targets.

Discrete signaling mechanisms of mTORC1 and mTORC2: Connected yet apart in cellular and molecular aspects.

Activation of PI3K/Akt/mTOR (mechanistic target of rapamycin) signaling cascade has been shown in tumorigenesis of numerous malignancies including glioblastoma (GB). This signaling cascade is frequently upregulated due to loss of the tumor suppressor PTEN, a phosphatase that functions antagonistically to PI3K. mTOR regulates cell growth, motility, and metabolism by forming two multiprotein complexes, mTORC1 and mTORC2, which are composed of special binding partners. These complexes are sensitive to distinct stimuli. mTORC1 is sensitive to nutrients and mTORC2 is regulated via PI3K and growth factor signaling. mTORC1 regulates protein synthesis and cell growth through downstream molecules: 4E-BP1 (also called EIF4E-BP1) and S6K. Also, mTORC2 is responsive to growth factor signaling by phosphorylating the C-terminal hydrophobic motif of some AGC kinases like Akt and SGK. mTORC2 plays a crucial role in maintenance of normal and cancer cells through its association with ribosomes, and is involved in cellular metabolic regulation. Both complexes control each other as Akt regulates PRAS40 phosphorylation, which disinhibits mTORC1 activity, while S6K regulates Sin1 to modulate mTORC2 activity. Another significant component of mTORC2 is Sin1, which is crucial for mTORC2 complex formation and function. Allosteric inhibitors of mTOR, rapamycin and rapalogs, have essentially been ineffective in clinical trials of patients with GB due to their incomplete inhibition of mTORC1 or unexpected activation of mTOR via the loss of negative feedback loops. Novel ATP binding inhibitors of mTORC1 and mTORC2 suppress mTORC1 activity completely by total dephosphorylation of its downstream substrate pS6KSer235/236, while effectively suppressing mTORC2 activity, as demonstrated by complete dephosphorylation of pAKTSer473. Furthermore, proliferation and self-renewal of GB cancer stem cells are effectively targetable by these novel mTORC1 and mTORC2 inhibitors. Therefore, the effectiveness of inhibitors of mTOR complexes can be estimated by their ability to suppress both mTORC1 and 2 and their ability to impede both cell proliferation and migration.

Successful Treatment of Complex Regional Pain Syndrome with Pseudoaneurysm Excision and Median Nerve Neurolysis.

BACKGROUND: Complex regional pain syndrome (CRPS), formerly referred to as reflex sympathetic dystrophy, is a pain syndrome characterized by severe pain, altered autonomic and motor function, and trophic changes. CRPS is usually associated with soft tissue injury or trauma. It has also been described as a rare complication of arterial access for angiography secondary to pseudoaneurysm formation. CASE DESCRIPTION: A 73-year-old woman underwent catheterization of the left brachial artery for angiography of the celiac artery. The following day, the patient noticed numbness and severe pain in the median nerve distribution of the left upper extremity. Over the next 6 months, the patient developed CRPS in the left hand with pain and signs of autonomic dysfunction. Further work-up revealed the formation of a left brachial artery pseudoaneurysm with impingement on the median nerve. She underwent excision of the pseudoaneurysm with decompression and neurolysis of the left median nerve. Approximately 6 weeks after surgery, the patient had noticed significant improvement in autonomic symptoms. CONCLUSIONS: This case involves a unique presentation of CRPS caused by brachial artery angiography and pseudoaneurysm formation. In addition, the case demonstrates the efficacy of pseudoaneurysm excision and median nerve neurolysis in the treatment of CRPS as a rare complication of arterial angiography.

Molecular Pathways Mediating Metastases to the Brain via Epithelial-to-Mesenchymal Transition: Genes, Proteins, and Functional Analysis.

BACKGROUND: Brain metastases are the leading cause of morbidity and mortality among patients with disseminated cancer. The development of metastatic disease involves an orderly sequence of steps enabling tumor cells to migrate from the primary tumor and colonize at secondary locations. In order to achieve this complex metastatic potential, a cancer cell is believed to undergo a cellular reprogramming process involving the development of a degree of stemness, via a proposed process termed epithelial-to-mesenchymal transition (EMT). Upon reaching its secondary site, these reprogrammed cancer stem cells submit to a reversal process designated mesenchymal-to-epithelial transition (MET), enabling establishment of metastases. Here, we examined the expression of markers of EMT, MET, and stem cells in metastatic brain tumor samples. MATERIALS AND METHODS: Immunohistochemical analyses were performed to establish the markers of EMT and MET. Co-expression of these markers was determined by immunofluorescence analysis. Gene-expression analysis was conducted using tissues from brain metastases of primary adenocarcinoma of the lung compared to non-metastatic tissue. Cell proliferation was carried out using 3- (4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide S-phase entry analysis, by determining the 5-ethynyl-2'-deoxyuridine incorporation. Scratch wound and chemotactic migration assays were performed in an astrocytic setting. RESULTS: Metastatic brain tumor samples displayed expression of epithelial markers (zinc finger protein SNAI1 and Twist-related protein-1), as well as the mesenchymal marker vimentin. The stem cell marker CD44 was also highly expressed. Moreover, co-expression of the epithelial marker E-cadherin with the mesenchymal marker vimentin was evident, suggesting a state of transition. Expression analysis of transcription factor genes in metastatic brain tumor samples demonstrated an alteration in genes associated with neurogenesis, differentiation, and reprogramming. Furthermore, tumor cells grown in astrocytic medium displayed increased cell proliferation and enhanced S-phase cell-cycle entry. Additionally, chemotactic signaling from the astrocytic environment promoted tumor cell migration. Primary tumor cells and astrocytes were also shown to grow amicably together, forming cell-to-cell interactions. CONCLUSION: These findings suggest that cellular reprogramming via EMT/MET plays a critical step in the formation of brain metastases, where the cerebral milieu provides a microenvironment suitable for the development of metastatic disease.