Endovascular thrombectomy for ischemic stroke with large infarct, short- and long-term outcomes: a meta-analysis of 6 randomised control trials.

Endovascular Thrombectomy (EVT) as first-line treatment of patients with large core ischemic infarct is a subject of debate. A systematic literature search was conducted in four electronic databases for randomized control trials (RCTs) comparing EVT to best medical treatment (BMT) for large core infarcts (ASPECTS ≤ 5). Relevant studies were added after screening for titles, abstracts, and complete text. Meta-analysis was performed. The continuous outcomes were analyzed using the standardized mean difference (SMD) and 95% CI, while the binary outcomes were analyzed using the risk ratio (RR) and 95% confidence interval (CI). A funnel plot was used to visually evaluate publication bias, and if feasible, Egger's test was used to validate. We included 1918 patients from six RCTs that compared EVT plus BMT and BMT alone in patients with large core infarct due to large vessel occlusion in the anterior circulation. There were 946 patients in the EVT group and 972 patients in the BMT group. The one-year outcomes are available for 314 patients in the EVT group and 292 patents in the BMT group from two RCTs. EVT group had statistically significant higher rate of 90-day mRS 0-1 (RR = 3.1, P-value < 0.0001), mRS 0-2 (RR = 2.64, P-value < 0.0001), mRS 0-3 (RR = 1.80, P-value < 0.0001), lower 90-day mean mRS score (SMD = -0.29, P-value < 0.0001), lower 90-day mortality rate (RR = 0.85, P-value = 0.015), and greater early neurological improvement (RR = 2.16, P-value < 0.00001) compared to the BMT group. However, the rates of symptomatic intracerebral hemorrhage (sICH) (RR = 1.76, P-value = 0.01) and any ICH (RR = 2.18, P-value < 0.00001) were higher in EVT group. Our finding showed that EVT plus BMT led to in an absolute improvement of 5%, 12%, and 16% in 90-day mRS 0-1, 0-2, and 0-3, respectively. In addition, patients in EVT plus BMT group had a 3% increased probability of experiencing sICH and were 32% more susceptible to any ICH. Moreover, the one-year mRS 0-2 (RR = 2.16, P-value < 0.00001) and mRS 0-3 (RR = 1.80, P-value < 0.0001) was significantly favor the EVT plus BMT over BMT alone. Although, the one-year mortality rate was not significantly differed between two groups (RR = 0.91, P-value = 0.31). There was no statistically significant difference observed between the EVT plus BMT group and the BMT group concerning new stroke, decompressive craniectomy, and serious adverse events. Combined data from six RCTs shows that EVT plus BMT provides significantly better short- and long-term functional outcomes with minimal increase in symptomatic hemorrhage over BMT in patient with large core infarcts.

Short- and long-term outcome and predictors in an international cohort of patients with neuro-COVID-19.

BACKGROUND AND PURPOSE: Despite the increasing number of reports on the spectrum of neurological manifestations of COVID-19 (neuro-COVID), few studies have assessed short- and long-term outcome of the disease. METHODS: This is a cohort study enrolling adult patients with neuro-COVID seen in neurological consultation. Data were collected prospectively or retrospectively in the European Academy of Neurology NEuro-covid ReGistrY ((ENERGY). The outcome at discharge was measured using the modified Rankin Scale and defined as 'stable/improved' if the modified Rankin Scale score was equal to or lower than the pre-morbid score, 'worse' if the score was higher than the pre-morbid score. Status at 6 months was also recorded. Demographic and clinical variables were assessed as predictors of outcome at discharge and 6 months. RESULTS: From July 2020 to March 2021, 971 patients from 19 countries were included. 810 (83.4%) were hospitalized. 432 (53.3%) were discharged with worse functional status. Older age, stupor/coma, stroke and intensive care unit (ICU) admission were predictors of worse outcome at discharge. 132 (16.3%) died in hospital. Older age, cancer, cardiovascular complications, refractory shock, stupor/coma and ICU admission were associated with death. 262 were followed for 6 months. Acute stroke or ataxia, ICU admission and degree of functional impairment at discharge were predictors of worse outcome. 65/221 hospitalized patients (29.4%) and 10/32 non-hospitalized patients (24.4%) experienced persisting neurological symptoms/signs. 10/262 patients (3.8%) developed new neurological complaints during the 6 months of follow-up. CONCLUSIONS: Neuro-COVID is a severe disease associated with worse functional status at discharge, particularly in older subjects and those with comorbidities and acute complications of infection.

Evaluating pituitary adenomas using national research databases: systematic review of the quality of reporting based on the STROBE scale.

The use of national research databases has become more prevalent for studying various neurosurgical diseases. Despite the advantages of using large databases to glean clinical insight, variation remains in the methodology and reporting among studies. Using STROBE and RECORD guidelines, we evaluated the quality of reporting of the database literature investigating surgical management of benign pituitary adenomas. In this systematic review of the PubMed/MEDLINE database, we identified studies employing large national research databases of patients who underwent surgery for benign pituitary adenoma. We evaluated each of these studies using the STROBE-RECORD reporting guideline criteria to assess their quality. A total of 42 studies from 2003 to 2020 were identified for inclusion. The two raters demonstrated a κ = 0.228 with 84% overall agreement. Commonly underreported criteria included bias (discussed in 56% of studies), main result reporting (70%), subgroup analysis (69%), generalizability (68%), and funding (57%). These factors, in addition to the data sources/measurement criteria, also had the largest discrepancies between reviewers. About 20% of administrative database reviews did not accurately address bias or control for confounding variables. We found frequent underreporting of crucial information and criteria that can be challenging to identify may limit large database studies of pituitary adenomas. Improved reporting of certain criteria is critical to optimize reader understanding of large database studies. This would allow better dissemination and implementation of study findings, especially as the use of these research tools increases.

Effect of patient age on glioblastoma perioperative treatment costs: a value driven outcome database analysis.

INTRODUCTION: Identification of groups of patients or interventions with higher associated treatment costs may be beneficial in efforts to decrease the overall financial burden of glioblastoma (GBM) treatment. The authors' objective was to evaluate perioperative surgical treatment cost differences between elderly and nonelderly patients with GBM using the Value Driven Outcome (VDO) database. METHODS: The authors obtained data from a retrospective cohort of GBM patients treated surgically (resection or biopsy) at their institution from August 2011 to February 2018. Data were compiled using medical records and the VDO database. RESULTS: A total of 181 patients with GBM were included. Patients were grouped into age < 70 years at time of surgery (nonelderly; n = 121) and ≥ 70 years (elderly; n = 60). Costs were approximately 38% higher in the elderly group on average (each patient was mean 0.68% of total cohort cost vs. 0.49%, p = 0.044). Higher age significantly, but weakly, correlated with higher treatment cost on linear regression analysis (p = 0.007; R2 = 0.04). Length of stay was significantly associated with increased cost on linear regression (p < 0.001, R2 = 0.84) and was significantly longer in the elderly group (8.7 ± 11.3 vs. 5.2 ± 4.3 days, p = 0.025). The cost breakdown by facility, pharmacy, supply/implants, imaging, and laboratory costs was not significantly different between age groups. Elderly patients with any postoperative complication had 2.1 times greater total costs than those without complication (p = 0.094), 2.9 times greater total costs than nonelderly patients with complication (p = 0.013), and 2.3 times greater total costs than nonelderly patients without complication (p = 0.022). CONCLUSIONS: GBM surgical treatment costs are higher in older patients, particularly those who experience postoperative complications.

Clinical potential of meningioma genomic insights: a practical review for neurosurgeons.

Meningiomas are among the most common intracranial pathological conditions, accounting for 36% of intracranial lesions treated by neurosurgeons. Although the majority of these lesions are benign, the classical categorization of tumors by histological type or World Health Organization (WHO) grade has not fully captured the potential for meningioma progression and recurrence. Many targeted treatments have failed to generate a long-lasting effect on these tumors. Recently, several seminal studies evaluating the genomics of intracranial meningiomas have rapidly changed the understanding of the disease. The importance of NF2 (neurofibromin 2), TRAF7 (tumor necrosis factor [TNF] receptor-associated factor 7), KLF4 (Kruppel-like factor 4), AKT1, SMO (smoothened), PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha), and POLR2 (RNA polymerase II subunit A) demonstrates that there are at least 6 distinct mutational classes of meningiomas. In addition, 6 methylation classes of meningioma have been appreciated, enabling improved prediction of prognosis compared with traditional WHO grades. Genomic studies have shed light on the nature of recurrent meningioma, distinct intracranial locations and mutational patterns, and a potential embryonic cancer stem cell-like origin. However, despite these exciting findings, the clinical relevance of these findings remains elusive. The authors review the key findings from recent genomic studies in meningiomas, specifically focusing on how these findings relate to clinical insights for the practicing neurosurgeon.

An Adult Case of Medulloblastoma with Multiple Lung Metastatic Lesions-Case Report and Literature Review.

Medulloblastoma (MB) cerebelli is a common brain tumor of the childhood. MB commonly spreads through cerebrospinal fluid; however, there are several reported cases of extracranial spread. The most common sites of extracranial metastasis are bones and bone marrow followed by peritoneum, liver, and lungs. Here, we report a case of pulmonary metastatic lesions of adult cerebellar MB that were discovered 1 year after the primary surgical treatment. We also tried to highlight similar reported cases in the literature.

Ossifying fibroma of the ethmoid and sphenoid sinuses: A report of a rare case and literature review.

Background: Fibro-osseous lesions include a variety of bone lesions with different clinical and histopathological features. Case Description: We report a case of cemento-ossifying lesion involving the left ethmoid and sphenoid sinus in a 17-year-old male patient. Computed tomography showed an expansile hyperdense lesion with sclerosed peripheral mantle epicentered on the left ethmoid and sphenoid sinus and extending into the left nasal cavity. Magnetic resonance imaging was done for preoperative planning. Transnasal endoscopic resection was performed and histopathological examination confirmed the diagnosis of ossifying fibroma (OF). Conclusion: Involvement of the ethmoid sinus with OF is a rare condition; therefore, we examined the literature for similar cases to highlight the possible clinical presentation and management. Endoscopic management is a safe, effective approach with a low rate of complications.

Venous sinus stenting for idiopathic intracranial hypertension: An updated Meta-analysis.

BACKGROUND: Idiopathic intracranial hypertension (IIH) is characterized by elevated intracranial pressure and primarily affects obese women of reproductive age. Venous sinus stenting (VSS) is a surgical procedure used to treat IIH, but its safety and efficacy are still controversial. METHODS: A systematic review and meta-analysis were conducted following PRISMA guidelines. Multiple databases were searched for studies evaluating the safety and efficacy of VSS in IIH patients and meta-analysis was performed to pool the data. RESULTS: A total of 36 studies involving 1066 patients who underwent VSS were included. After VSS, a significant reduction in trans-stenotic gradient pressure was observed. Patients also showed significantly lower cerebrospinal fluid (CSF) opening pressure. Clinical outcomes demonstrated improvement in tinnitus (95%), papilledema (89%), visual disturbances (88%), and headache (79%). However, 13.7% of patients experienced treatment failure or complications. The treatment failure rate was 8.35%, characterized by worsening symptoms and recurrence of IIH. The complications rate was 5.35%, including subdural hemorrhage, urinary tract infection, stent thrombus formation, and others. CONCLUSION: VSS appears to be a safe and effective treatment option for IIH patients who are unresponsive to medical therapy or have significant visual symptoms. However, long-term outcomes and safety of the procedure require further investigation.

Subtemporal Approach for the Treatment of Ruptured and Unruptured Distal Basilar Artery Aneurysms: Is There a Contemporary Use?

BACKGROUND AND OBJECTIVES: Distal basilar artery aneurysms (DBAs) are high-risk lesions for which endovascular treatment is preferred because of their deep location, yet indications for open clipping nonetheless remain. The subtemporal approach allows for early proximal control and direct visualization of critical posterior perforating arteries, especially for posterior-projecting aneurysms. Our objective was to describe our clinical experience with the subtemporal approach for clipping DBAs in the evolving endovascular era. METHODS: This was a retrospective, single-institution case series of patients with DBAs treated with microsurgery over a 21-year period (2002-2023). Demographic, clinical, and surgical data were collected for analysis. RESULTS: Twenty-seven patients underwent clipping of 11 ruptured and 16 unruptured DBAs with a subtemporal approach (24 female; mean age 53 years). Ten patients had expanded craniotomies for treatment of additional aneurysms. The aneurysm occlusion rate was 100%. Good neurological outcomes as defined by the modified Rankin Scale score ≤2 and Glasgow Outcome Scale score ≥4 were achieved in 21/27 patients (78%). Two patients died before hospital discharge, one from vasospasm-induced strokes and another from an intraoperative myocardial infarction. CONCLUSION: These results demonstrate that microsurgical clip ligation of DBAs using the subtemporal approach remains a viable option for complex lesions not amenable to endovascular management.

Expression of Anaplastic Lymphoma Kinase (ALK) in glioma and possible clinical correlations. A retrospective institutional study.

BACKGROUND: Glioblastoma is considered the most aggressive primary brain tumor. Recurrence after treatment is a significant problem with a failed response to optimal treatment. The recurrence of GBM is linked to different cellular and molecular pathways. Nationwide, in Egypt, astrocytic tumors are the most commonly diagnosed CNS tumor. Anaplastic Lymphoma Kinase (ALK CD246) is an enzymatic protein (RTK) belonging to the insulin receptors superfamily. METHODS: This is a retrospective study including sixty cases of astrocytic tumors (males = 40, mean age = 31.5), (females = 20, mean age = 37.77) obtained through collecting archived paraffin blocks of astrocytic tumor from the Pathology Department, Cairo University Faculty of Medicine during the period from January 2015 till January 2019. All cases were evaluated for ALK expression trying to find any clinical correlations with the clinical data. RESULTS: Correlations were made using a scatterplot matrix correlogram. There was a significant correlation between tumor recurrence and ALK expression (r = 0.8, P < 0.01), and incidence of postoperative seizures (r = 0.8, P < 0.05), and between mean age and score tumor (r = 0.8, P < 0.05). CONCLUSION: Expression of ALK was found to be abundant among high-grade gliomas and tumor recurrence rate was higher in ALK-positive patients. Further studies are needed to evaluate the potential use of ALK as a prognostic marker in cases of GBM.

Neurosurgical intervention in an unusual case of extensive acute disseminated encephalomyelitis - A case report and literature review.

Background: The clinical presentations of demyelinating diseases are variable and can range from mild symptoms to fulminant presentations. Acute disseminated encephalomyelitis is one of those diseases which usually follow an infection or vaccination. Case Description: We report a case of extensive acute demyelinating encephalomyelitis (ADEM) with massive brain swelling. A 45-year-old female presented to the emergency room with status epilepticus. Patient has no history of any associated medical problems. Glasgow coma scale (GCS) was 15/15. CT brain was normal. Lumbar puncture was done and cerebrospinal fluid showed pleocytosis and increased protein content. About 2 days after admission, the conscious level rapidly deteriorated and GCS was 3/15, with the right pupil fully dilated and unreactive to light. Computed tomography and magnetic resonance imaging brain were done. We performed an urgent decompressive craniectomy as a life-saving procedure. Histopathological examination was suggestive of ADEM. Conclusion: Few cases of ADEM with brain swelling were reported, but there is no solid consensus about the appropriate management of these cases. Decompressive hemicraniectomy is a possible choice, but further research is needed to evaluate the proper timing, and indication of surgery.

Spontaneous acute subdural hematoma as a complication of preeclampsia. A case report and literature review.

Background: Acute subdural hematoma (ASDH) is a common form of intracranial bleeding that may be fatal. Trauma is a major cause, while a subset of cases may occur spontaneously. The authors of this article present a case of spontaneous ASDH in the context of preeclampsia and review similar cases in the literature to identify the prognosis. Case Description: A healthy 27-year-old woman presented in her first pregnancy which was complicated with pregnancy-induced hypertension and was sent to a provincial local maternity hospital at 37 weeks of gestation. On day 4 postpartum, the patient complained of severe headache, vomiting and blurred vision. Fundus examination showed papilledema and magnetic resonance imaging showed right acute frontoparietal subdural hematoma. The hematoma was surgically evacuated with decompressive craniotomy. Postoperatively, the patient's symptoms improved. Conclusion: Spontaneous ASDH is a rare event in the context of preeclampsia; however, it should be considered as one of its possible complications. Research should be directed to emphasize on the possibility of spontaneous ASDH as a cause of neurological deterioration in those cases. A proper diagnosis and early intervention for these cases are crucial for both the mother and the fetus.

Tension pneumocephalus as a complication of surgical evacuation of chronic subdural hematoma: case report and literature review.

The management of symptomatic chronic subdural hematoma (CSDH) is surgical evacuation and prognosis in most cases is good. Tension pneumocephalus is the presence of air under pressure in the intracranial cavity. A case of tension pneumocephalus developing as a complication of burr hole evacuation of CSDH is illustrated. In this case, tension pneumocephalus was managed by reopening the wound and saline irrigation with a subdural drain placement. Considering this case report and after a careful review of the literature, the physiopathology, diagnosis, and treatment of this complication are highlighted in the article.

Traumatic Optic Neuropathy: Update on Management.

Traumatic optic neuropathy is one of the causes of visual loss caused by blunt or penetrating head trauma and is classified as both direct and indirect. Clinical history and examination findings usually allow for the diagnosis of traumatic optic neuropathy. There is still controversy surrounding the management of traumatic optic neuropathy; some physicians advocate observation alone, while others recommend steroid therapy, surgery, or both. In this entry, we tried to highlight traumatic optic neuropathy's main pathophysiologic mechanisms with the most available updated treatment. Recent research suggests future therapies that may be helpful in traumatic optic neuropathy cases.

Medical Management of Meningiomas.

Meningiomas represent the most common type of benign tumor of the extra-axial compartment. Although most meningiomas are benign World Health Organization (WHO) grade 1 lesions, the increasingly prevalent of WHO grade 2 lesion and occasional grade 3 lesions show worsened recurrence rates and morbidity. Multiple medical treatments have been evaluated but show limited efficacy. We review the status of medical management in meningiomas, highlighting successes and failures of various treatment options. We also explore newer studies evaluating the use of immunotherapy in management.

Systematic Review of Treatment Options and Therapeutic Responses for Lesions of the Sella and Orbit: Evidence-Based Recommendations.

OBJECTIVE: Inflammatory pathologies of the sella and orbit are rare but require prompt diagnosis to initiate effective treatment. Because uniform recommendations for treatment are currently lacking, we performed an evidence-based review to identify recommendations. METHODS: We performed a literature search of the PubMed, Embase, and Web of Science databases to identify papers evaluating treatment of inflammatory pathologies of the sella and orbit. We used PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to define recommendations, specifically examining aggregated sample sizes, disease-specific patient follow-up, and clinical trials focused on inflammatory diseases of the sella and orbit. RESULTS: A total of 169 studies were included and organized by disease pathology. Treatments for various pathologies were recorded. Treatment options included surgery, radiation, steroids, targeted treatments, immunomodulators, intravenous immune globulin, and plasmapheresis. Steroids were the most often employed treatment, second-line management options and timing varied. Pathological diagnosis was highly associated with treatment used. Most evidence were level 3 without available control groups, except for 13 trials in neuromyelitis optica with level 1 or 2 evidence. CONCLUSIONS: This is the first evidence-based review to provide recommendations on specific treatments for pathologies of the orbit and sella. The reported data may be useful to help guide randomized clinical trials and provide resource for clinical management decisions based on the available evidence.

Carotid endarterectomy versus carotid stenting for asymptomatic carotid stenosis: Evaluating the overlapping meta-analyses of randomized controlled trials.

Background: Asymptomatic carotid stenosis is associated with increased risk of ischemic stroke. The management of asymptomatic carotid stenosis ranges from open surgical approaches, minimally invasive endovascular interventions, and medical therapeutics. However, the research synthesis comparing these interventions, as shown by the scattered and overlapping published meta-analysis, has been inconsistent and non-comprehensive. Methods: Using previously-employed methods, we searched for and compared published meta-analyses comparing carotid endarterectomy and carotid stenting. A comprehensive search was conducted for all relevant studies published until November 13th, 2021, using the following databases: PubMed/MEDLINE, Scopus, Web of Science, Cochrane Library, OVID, and Google Scholar. Results: Five meta-analysis studies were included in this review. In summary, clinical findings were: carotid endarterectomy reduced the rate of ischemic stroke and stroke-related mortality, but led to a higher rate of intraoperative cranial nerve injury. There was no significant difference between carotid endarterectomy and carotid stenting in ipsilateral stroke and myocardial infarction events. Conclusions: The clinical findings favor the carotid endarterectomy over the carotid stenting in terms of stroke incidence (overall and minor events) and stroke-related mortality rates. However, the carotid stenting was superior to the carotid endarterectomy in the events of cranial nerve injury during the intervention.

Recurrent meningioma: When to intervene.

Meningioma occurs most frequently as a benign tumor central nervous system that is common in old females. Radiation exposure and deletion of the NF2 gene are known risk factors. However, there is no consensus about the role of sex hormones. Meningiomas are usually benign tumors, but 6% can be anaplastic or atypical. Most asymptomatic patients do not require treatment, but complete surgical resection is recommended for symptomatic patients. If a tumor returns after being resected previously, it is recommended to be resected, followed by radiotherapy in some cases. Meningiomas (benign, atypical, and malignant) recurring after standard treatment fails could be treated with hormone therapy, chemotherapy, target therapy, and calcium channel blockers.

Vitamin D and its' role in Parkinson's disease patients with SARS-CoV-2 infection. A review article.

A novel coronavirus reportedly called 2019-nCoV started to spread around the world at the end of 2019. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was later renamed after links with SARS were observed. Multiple studies have reported possible connections between the COVID-19 virus and neurodegenerative diseases, including Parkinson's disease. Theories support that vitamin D deficiency plays a part in the pathogenicity of Parkinson's disease or the credibility of the associated dopamine system. Administration of vitamin D3 was shown to significantly enhance the motor and non-motor manifestations of Parkinson's disease and enhance the quality of life. Also, multiple recent reviews have shown specific ways in which vitamin D reduces the risk of pathogenic infections. Recent studies supported the potential role of vitamin D in reducing the risk of COVID-19 infections and mortality. On the immunological level, immune response regulation remains one of the well-recognized actions of vitamin D. Vitamin D deficiency has been linked to complications in patients with SARS-CoV-2 infection and Parkinson's disease. Whereas more studies are required, Vitamin D supplementation with a moderate and well-calculated dosage of vitamin D3 in patients with Parkinson's disease can help minimize the risk and burden of COVID-19 complications.

Impact of COVID-19 on neurosurgical service: A one-year experience from a provincial countryside hospital in a rural area in north Egypt.

BACKGROUND: Globally, there is a shooting pandemic that affected many healthcare systems. Healthcare facilities had to set up strategies to avoid exhaustion while facing a catastrophic health problem. Vaccines or perfect therapies were not available over a long pandemic time and also no certified immunity against that disease is guaranteed. Therefore, it is probable that healthcare systems will face it for an exceptionally long period. That already had a grave effect on the strategy of daily practice of different specialties' services at healthcare centers. METHODS: We tried simply to share a countryside hospital's expertise in managing neurosurgical cases amid a dreadful health crisis. Healthcare workers' safety and patient safety were typical priorities for neurosurgical service at Damietta Specialized Hospital. We expose the lines of management, triaging cases, the methods of handling confirmed and suspected neurosurgical patients, and strategies for discharging and following up patients. We identified hospital admission and discharge records starting from February 2020 till February 2021 to track the neurosurgical case burden, the state of service offered and the rate of infection among healthcare workers who participated in surgeries. RESULTS: At the peak time of the COVID­19 pandemic in Egypt starting from February 2020 till February 2021, we have admitted about 500 neurosurgical patients. About 400 (80%) of them did surgeries according to the triaging protocol of the hospital. About 150 (30%) of those who did surgeries were urgent and the rest were borderline or semi­urgent. About 20 (4%) were tested COVID-19 positive and six of them died due to acute respiratory distress syndrome. Only two mortality cases were reported due to post-operative complications and not related to SARS­CoV­2 infection. The rest of the cases (97.6%) were discharged for follow­up without complications. No neurosurgeons but three anesthesia staff were infected with SARS­CoV­2. A successful undisturbed neurosurgical care was available for patients during COVID-19 time. CONCLUSIONS: Following the suggested strategies, a rural area-serving hospital managed to provide uninterrupted neurosurgical care amid COVID-19 pandemic in Egypt. Rural areas in developing countries are in need of strategies to deal with pandemics in the future without dismantling the normal health system, especially for life­saving cases in a critical specialty as neurosurgery.