The experience of patients undergoing awake craniotomy for intracranial masses: expectations, recall, satisfaction and functional outcome.

Introduction. Awake craniotomy is a well-established neurosurgical technique for lesions involving eloquent cortex, however, there is little information regarding patients' subjective experience with this type of surgery. Here we explore the expectations, recall, satisfaction and functional outcome of patients undergoing awake craniotomy. Methods. Three semi-structured interviews using closed- and open-ended questions were conducted with each of 26 consecutive patients (17 males, 9 females; aged 16-78 years) who underwent their first awake craniotomy between 2007 and 2009. Seven patients were interviewed retrospectively, 19 prospectively. Clinical data are included. Results. The following themes emerged from this study: (1) most patients demonstrated a good understanding of the rationale behind awake craniotomy; (2) patients felt the asleep-awake-asleep anaesthetic protocol used in this series was appropriate; (3) patients' confidence and preparedness for surgery was high, attributed to preparation by the surgical team. Seven of 26 (27%) patients had no recollection of being awake. Most patients had a positive anaesthetic and surgical experience, while a minority of patients reported experiencing more than slight pain (2/26; 8%) and discomfort (3/26; 12%), fear (4/26; 15%) or claustrophobia (1/26; 4%) intra-operatively. At follow-up (6 weeks post-operatively), most patients were functionally unimpaired; there was only one permanent neurological complication of surgery. We found that 24/26 (92%) patients were satisfied with their experience; one patient had no opinion and another one was unsatisfied. Five of 26 (19%) patients still reported more than slight discomfort, and 3/26 (12%) reported more than slight pain attributable to the surgery. A summary of the English peer-reviewed literature on the patient experience of awake craniotomy is also incorporated. Conclusions. This study confirms that awake craniotomy using the 'asleep-awake-asleep' anaesthetic protocol is a generally safe and well-tolerated procedure associated overall with satisfactory patients' experiences and neurological outcomes.

Adverse impact of smoking on the spine and spinal surgery.

BACKGROUND: Tobacco smokers and companies are well aware that smoking increases the risks for cancers, vascular morbidity, and early mortality. This is a review of the plethora of adverse effects chronic smoking has on spinal tissues and spinal surgery. METHODS: Medline (PubMed) and Google Scholar databases were searched for pertinent literature through keywords related to smoking, spondylosis, and spinal surgery. RESULTS: Smoking accelerates spondylosis by impairing spinal tissue vascular supply through atherosclerosis and thrombosis, while inducing local hypoxia, inflammation, proteolysis, and cell loss. It, thus, compromises disc, cartilage, synovium, bone, and blood vessels. It can lead to early surgery, delayed wound healing, increased surgical site infection, failed fusion, more re-operations, and chronic spinal pain. CONCLUSION: There is ample evidence to support surgeons' declining to operate on chronic smokers. The need for immediate and permanent smoking cessation and its potential benefits should be emphasized for the patient considering or who has undergone spinal surgery.

Aerospace Implications of Key Neurological Conditions.

INTRODUCTION: The neurological impact (or lack thereof) of certain medical histories and imaging findings is important to understand in the context of air and spaceflight. There are a number of neurological conditions that, if present in pilots and astronauts, carry variable (and sometimes adverse) functional implications for safety and overall mission success. In this systematic overview, the authors will refer to the relevant clinical and radiological features of brain tumors and vascular anomalies, cerebral edema and intracranial hypertension, concussion and the traumatic brain injury (TBI) spectrum, hematomas, cerebrospinal fluid circulation anomalies including hydrocephalus and sequestrations, spinal degenerative changes, and cerebral ischemia and demyelination. It is notable that these last two conditions have recently been reported to be a complication in some people with coronavirus disease 2019 (COVID-19). A paradigm for practical neurological workup of symptomatic pilots and astronauts will be discussed, as will the controversial notion of pre-emptive radiological screening (vs. not screening) in asymptomatic or clinically occult situations. The concepts of medical surveillance in the setting of known or diagnosed pathologies, and expert panel review and simulator and flight checks in complex neurological cases, are also elaborated on in this paper. We believe this overview will contribute toward the enhancement of a broad understanding of neurological conditions, their clinical workup, and their precautionary management in the setting of aviation and aerospace.Khurana VG, Jithoo R, Barnett M. Aerospace implications of key neurological conditions. Aerosp Med Hum Perform. 2021; 92(2):113119.

Epidemiological evidence for a health risk from mobile phone base stations.

Human populations are increasingly exposed to microwave/radiofrequency (RF) emissions from wireless communication technology, including mobile phones and their base stations. By searching PubMed, we identified a total of 10 epidemiological studies that assessed for putative health effects of mobile phone base stations. Seven of these studies explored the association between base station proximity and neurobehavioral effects and three investigated cancer. We found that eight of the 10 studies reported increased prevalence of adverse neurobehavioral symptoms or cancer in populations living at distances < 500 meters from base stations. None of the studies reported exposure above accepted international guidelines, suggesting that current guidelines may be inadequate in protecting the health of human populations. We believe that comprehensive epidemiological studies of long-term mobile phone base station exposure are urgently required to more definitively understand its health impact.

Intuitiveness, quality and utility of intraoperative fluorescence videoangiography: Australian Neurosurgical Experience.

INTRODUCTION: The authors have undertaken a study of their intraoperative experience with indocyanine green fluorescence videoangiography (ICGFV). In particular, the intuitiveness, image quality and clinical utility of this technology have been assessed. METHODS: The records of forty-six consecutive craniotomies utilising ICGFV have been retrospectively reviewed: There were 27 aneurysms, 2 extracranial-intracranial (EC-IC) bypasses, 5 arteriovenous malformations (AVM), 1 dural arteriovenous fistula (DAVF), 3 cavernomas, 5 meningiomas, and 3 gliomas. ICGFV was used in 5 awake-craniotomy patients. ICGFV was performed using a Leica OH4 surgical microscope with integrated near-infrared camera and ICG-PULSION. RESULTS: All attempts of intraoperative ICGFV were intuitive. Image quality and resolution were excellent. Arterial and venous phases were comparable to digital subtraction angiography (DSA) but field of view was relatively limited. In 12 operations (26%) the surgeon was substantially benefited from ICGFV findings. In 22 operations (48%), ICGFV was useful but did not influence surgical management. ICGFV was of no benefit in 11 operations (24%) and was misleading in 1 (2%). In this series, ICGFV was of benefit to 1 of 11 (9%) patients with an intracranial neoplasm or cavernoma. CONCLUSIONS: ICGFV is safe, intuitive and provides neurosurgeons with high quality, valuable, real-time imaging of cerebrovascular anatomy. It can assist in intraoperative surgical management and/or stroke prevention particularly during aneurysm clipping, EC-IC bypass and AVM/DAVF surgery.

Intraoperative rupture of brainstem cavernous malformation. Case report.

Although cavernous malformations (CMs) are an important cause of intracranial hemorrhage, the natural history of these lesions is controversial. Both retrospective and prospective studies undertaken to define risk factors for hemorrhage from CMs have consistently identified the location of a lesion as a factor that has a significant impact on the rate of rupture, and brainstem CMs consistently have a higher rate of symptomatic hemorrhage than those at other locations. The mechanism underlying this disparity in rupture rates, however, remains obscure. Most authors attribute the difference, at least partially, to the sensitivity of the brainstem to hemorrhage. Regardless, the specific factors that cause a given CM to rupture are unknown. The authors report their first encounter with an intraoperative rupture of a CM in the brainstem. This case underscores the risks encountered during the surgical approach to brainstem CMs and may provide insight into the pathophysiological mechanisms underlying the rupture of these lesions.

Update on evidence for a genetic predisposition to cerebral vasospasm.

Considerable evidence links cerebral vasospasm to the decreased bioavailability of endothelial nitric oxide synthase (eNOS) after aneurysmal subarachnoid hemorrhage (SAH). In recent studies from the cardiology literature, researchers have suggested that a genetic predisposition to coronary vasospasm might develop as the result of a T-786C single nucleotide polymorphism (SNP) in the eNOS gene. The authors of this study attempted to determine if there may be a similar genetic predisposition toward cerebral vasospasm. The authors prospectively identified 28 patients with Fisher Grade 3 SAH from a group of 51 consecutive patients with ruptured intracranial saccular aneurysms. Genomic DNA was isolated from a peripheral blood sample obtained with permission from each patient. Gene microarray technology was used to assay the samples for the presence and distribution of certain key eNOS gene polymorphisms. Clinical, radiological, and genomic data were analyzed. The finding of eNOS T-786C SNP could be used to significantly differentiate between the presence and severity of cerebral vasospasm (p = 0.04). The findings from this preliminary study support similar findings in the coronary vasospasm literature as well as the hypothesis that a predisposition toward cerebral vasospasm may be related partially to genetic factors, which needs to be confirmed in a larger study. Such gene-based information may be important in rapidly identifying patients at increased risk of vasospasm after SAH, independent of their Fisher grade. In this article, the authors review key studies in this area.

The presence of tandem endothelial nitric oxide synthase gene polymorphisms identifying brain aneurysms more prone to rupture.

OBJECT: It is becoming apparent that the presence of certain genetic variations (polymorphisms) may increase the individual's susceptibility to cardiovascular diseases, even in the absence of a family history. We hypothesized that brain aneurysms more prone to rupture may be identified on the basis of an individual's genotype for endothelial nitric oxide synthase (eNOS), a critical vasomodulatory protein found to be increasingly relevant to the pathobiology of aneurysms. METHODS: Patients' clinical data were recorded prospectively. Genomic DNA was isolated from blood samples obtained from individuals presenting consecutively to the Mayo Clinic with ruptured (58 patients) or unruptured (49 patients) intracranial saccular aneurysms. Using polymerase chain reaction and gene microarray technology, the following eNOS genetic polymorphisms were studied: intron-4 27-base pair variable number of tandem repeats (27 VNTR); promoter single nucleotide polymorphism (T-786C SNP); and exon-7 SNP (G894T SNP). Both groups of patients had similar demographic and clinical characteristics. For all three polymorphisms, variant alleles (p < or = 0.003) and their corresponding genotypes (p < or = 0.006) were found two to four times more frequently in patients with ruptured aneurysms than in patients with unruptured aneurysms. Strikingly, the odds ratio for presenting with a ruptured brain aneurysm among individuals demonstrating the copresence of all three variant alleles was 11.4 (95% confidence interval 1.7-75.9, p = 0.004). CONCLUSIONS: The authors have uniquely identified a set of tandem eNOS gene variations whose presence can be used to identify patients with aneurysms likely to rupture. We believe that if this finding is reproducible in a large multicenter study, in addition to known anatomical factors a rapid and cost-effective screening tool will become available to clinicians as a genetic aid to predict the risks of rupture in patients presenting with unruptured intracranial aneurysms.

Endothelial nitric oxide synthase T-786C single nucleotide polymorphism: a putative genetic marker differentiating small versus large ruptured intracranial aneurysms.

BACKGROUND AND PURPOSE: Anecdotal evidence exists for at least 2 subpopulations of intracranial saccular aneurysms, namely, those that may form rapidly and rupture when small versus those that enlarge slowly and may rupture particularly when > or =10 mm in diameter. We sought to determine whether the endothelial nitric oxide synthase (eNOS) T-786C single nucleotide polymorphism (SNP), implicated in cardiovascular disease susceptibility, could facilitate differentiation between small (< or =5 mm) versus large (> or =10 mm) ruptured aneurysms. METHODS: In accordance with institutional guidelines, clinical data were recorded prospectively and genomic DNA was isolated from blood samples obtained from 52 aneurysmal subarachnoid hemorrhage (SAH) patients (cases) and 90 randomly selected controls. Samples were assayed for eNOS gene promoter T-786C SNP with the use of gene microarray technology. Statistical analyses included multiple logistic regression. RESULTS: Although there was no difference in genotype distributions between cases and controls, all 13 patients with large aneurysms were (T/C) heterozygous for the polymorphism, while 9 of 22 patients (41%) with small aneurysms were (T/T or C/C) homozygous (P=0.01). The mean (+/-SD) ruptured aneurysm diameter among all heterozygotes (8.5+/-5.2 mm) was significantly greater than that for C/C (6.0+/-2.3 mm) or T/T (4.7+/-1.8 mm) homozygotes (P=0.04). With the use of multivariate analysis, heterozygosity remained significantly associated with aneurysm size > or =10 mm (P=0.03). CONCLUSIONS: The eNOS T-786C SNP distinguishes genetically between small and large ruptured aneurysms. Although not predictive of SAH in the population at large, our data suggest that among persons with known intracranial aneurysms, eNOS T-786C genotype may be a factor influencing the size at which an aneurysm ruptures, a finding that should be taken into consideration along with other anatomic features of the aneurysm.

Protective vasomotor effects of in vivo recombinant endothelial nitric oxide synthase gene expression in a canine model of cerebral vasospasm.

BACKGROUND AND PURPOSE: Post-subarachnoid hemorrhage (SAH) cerebral vasospasm is a potentially devastating condition whose pathogenesis involves impaired nitric oxide (NO) bioavailability. We aimed to determine whether recombinant endothelial NO synthase (eNOS) gene expression may protect vasomotor function and prevent vasospasm in a canine experimental SAH model. METHODS: Recombinant adenoviral vectors (5x10(9) plaque-forming units/animal) encoding genes for eNOS (AdeNOS) and beta-galactosidase (AdLacZ) or vehicle were injected into the cerebrospinal fluid (CSF) of dogs on day -1 (ie, 24 hours before the first intra-CSF injection of blood on day 0). Cerebral angiography was performed at day 0 (baseline) and day 7 (immediately before death), and tissues were harvested for additional studies. RESULTS: Western analysis and immunohistochemistry detected recombinant eNOS exclusively in cerebral arteries isolated from AdeNOS-transduced dogs, and in this group of animals CSF NO concentrations were significantly elevated by day 2. Analysis of day 7 versus day 0 cerebral angiograms for each group revealed significant spasm at the basilar artery midpoint in AdLacZ-transduced and nontransduced dogs but not in AdeNOS-transduced dogs. Isometric force recording of basilar arteries isolated from AdeNOS-transduced dogs showed significantly augmented relaxations to bradykinin and reduced contractions to endothelin-1. CONCLUSIONS: Our results suggest that expression of recombinant eNOS in the adventitia of cerebral arteries may contribute toward protection against post-SAH vasospasm.

Translational paradigms in cerebrovascular gene transfer.

Gene transfer involves the use of an engineered biologic vehicle known as a vector to introduce a gene encoding a protein of interest into a particular tissue. In diseases with known defects at a genetic level, gene transfer offers a potential means of restoring a normal molecular environment via vector-mediated entry (transduction) and expression of genes encoding potentially therapeutic proteins selectively in diseased tissues. The technology of gene transfer therefore underlies the concept of gene therapy and falls under the umbrella of the current genomics revolution. Particularly since 1995, numerous attempts have been made to introduce genes into intracranial blood vessels to demonstrate and characterize viable transduction. More recently, in attempting to translate cerebrovascular gene transfer technology closer to the clinical arena, successful transductions of normal human cerebral arteries ex vivo and diseased animal cerebral arteries in vivo have been reported using vasomodulatory vectors. Considering the emerging importance of gene-based strategies for the treatment of the spectrum of human disease, the goals of the present report are to overview the fundamentals of gene transfer and review experimental studies germane to the clinical translation of a technology that can facilitate genetic modification of cerebral blood vessels.

Endothelial nitric oxide synthase gene polymorphisms predict susceptibility to aneurysmal subarachnoid hemorrhage and cerebral vasospasm.

Rupture of an intracranial aneurysm (subarachnoid hemorrhage) is a potentially devastating condition frequently complicated by delayed cerebral ischemia from sustained contraction of intracranial arteries (cerebral vasospasm). There is mounting evidence linking the formation of intracranial aneurysms and the pathogenesis of post-subarachnoid hemorrhage vasospasm to aberrant bioavailability and action of the vasodilator molecule nitric oxide generated by isoforms of nitric oxide synthase. In humans, the gene encoding the endothelial isoform of nitric oxide synthase (eNOS) is known to be polymorphic, with certain polymorphisms associated with increased cardiovascular disease susceptibility. In this prospective clinical study involving 141 participants, we used gene microarray technology to demonstrate that the eNOS gene intron-4 27-base pair variable number tandem repeat polymorphism (eNOS 27 VNTR) predicts susceptibility to intracranial aneurysm rupture, while the eNOS gene promoter T-786C single nucleotide polymorphism (eNOS T-786C SNP) predicts susceptibility to post-subarachnoid hemorrhage vasospasm. We believe that genetic information such as this, which can be obtained expeditiously at the time of diagnosis, may be used as a helpful adjunct to other clinical information aimed at predicting and favorably modifying the clinical course of persons with intracranial aneurysms.

Singing paraplegia: a distinctive manifestation of a spinal dural arteriovenous fistula.

The unique case of a baritone with a spinal dural arteriovenous fistula (SDAVF) causing recurrent, acute paraplegia during singing is described. This case underscores the presence of impaired venous drainage in these lesions and the high level of clinical suspicion required for their diagnosis in patients with any myelopathy.

A pilot study of dendroaspis natriuretic peptide in aneurysmal subarachnoid hemorrhage.

OBJECTIVE: Hypovolemia after aneurysmal subarachnoid hemorrhage (SAH) may be mediated by natriuretic peptides and can further impair cerebral perfusion in dysautoregulated and vasospastic arterial territories. Dendroaspis natriuretic peptide (DNP), derived from the venom of Dendroaspis augusticeps, the Green Mamba snake, has recently been discovered in human plasma and atrial myocardium. There is no information regarding the presence or putative role of this peptide in patients with aneurysmal SAH. METHODS: A sensitive and specific DNP radioimmunoassay was performed on venous blood samples obtained on post-SAH Days 1, 3, and 7 from 10 consecutive SAH patients (cases) and randomly from 9 healthy volunteers (controls). Clinical and laboratory data, including daily serum sodium concentration and fluid balance, were collected prospectively up to 7 days after the ictus. RESULTS: Increase in plasma DNP levels occurred in five (63%) of eight patients who had DNP levels measured on Days 1 and 3 (mean increase, 29%). An increase in DNP level was significantly associated with development of a negative fluid balance (P = 0.003) and hyponatremia (P = 0.008). Three (75%) of the four patients who developed cerebral vasospasm during this study experienced an increase in DNP levels from Days 1 to 3. CONCLUSION: The present study is the first to find a significant association between elevated levels of DNP, a new member of the natriuretic peptide family, and the development of diuresis and natriuresis in patients with aneurysmal SAH. Our findings warrant further investigation by means of a large-scale, prospective, case-control study.

Evolution of a cochlear schwannoma on clinical and neuroimaging studies. Case report.

The authors report on a patient with a rare schwannoma that arose from the cochlear division of the vestibulocochlear nerve. Distinctively, the lesion appeared to arise from the cochlea itself and was monitored with clinical and neuroimaging studies for 12 years before it was diagnosed and treated. The atypical occurrence of schwannomas of the vestibulocochlear nerve originating in the inner ear structures underscores the high level of clinical suspicion required for the diagnosis of these lesions in patients presenting with persistent auditory and vestibular symptoms.

Update on genetic evidence for rupture-prone compared with rupture-resistant intracranial saccular aneurysms.

OBJECT: Anecdotal evidence exists for at least two subpopulations of intracranial saccular aneurysms; those that form rapidly and rupture when small and those that enlarge slowly and are particularly prone to rupture when they are 10 mm or more in diameter. The goal in this study was to determine if there was genetic evidence to support the classification of intracranial saccular aneurysms as 'rupture-prone' or 'rupture-resistant' lesions. METHODS: The authors prospectively obtained and analyzed clinical and genetic data in a cohort of 197 individuals composed of 58 patients with ruptured intracranial saccular aneurysms, 49 with unruptured aneurysms, and 90 healthy community volunteers. Based on recent studies supporting an increasingly relevant role for the critical vasomodulatory protein endothelial nitric oxide synthase (eNOS) in aneurysm pathobiology, the authors assayed blood from all 197 participants to determine and compare their eNOS genotypes. The eNOS gene intron 4 27-base pair variable-number tandem-repeat polymorphism was significantly overrepresented in persons with ruptured intracranial saccular aneurysms compared with community volunteers (p < 0.002). When comparing eNOS genotypes among patients with ruptured or unruptured aneurysms, an approximately 10-fold increase in the odds of presenting with brain aneurysm rupture was found among individuals with multiple variant eNOS alleles (p = 0.004). CONCLUSIONS: Uniquely, the authors have identified a set of eNOS gene variations whose presence indicates patients with intracranial saccular aneurysms that are more prone to rupture. The authors conclude that if these findings are reproducible in the setting of a large multicenter study, then in addition to known anatomical factors, a rapid and costeffective genetic screening tool will become available to clinicians as an aid to predicting rupture risks in patients presenting with unruptured intracranial aneurysms.

An overview of concussion in sport.

Concussion is a sudden-onset, transient alteration of consciousness due to a combination of functional and structural brain disturbances following a physical impact transmitted to the brain. It is a common, although likely underreported, condition encountered in a wide range of sports. In the Australian Football League, concussion is estimated to occur at a rate of approximately seven injuries per team per season. While many instances of concussion are clinically mild, there is emerging evidence that a player's full recovery from a concussive injury may be more delayed and the sequelae of repeated concussions more severe than previously thought. In this light, a more conservative and rigorous approach to managing players with concussive injuries may be warranted, with the guiding principle being the player's immediate and long-term welfare. The current paper reviews the sports concussion literature. The definition, epidemiology, aetiology, pathophysiology, structural pathology, clinical features, assessment and investigation, treatment principles, and short-term and potential long-term complications of concussion are discussed. Special considerations in paediatric sports concussion, and the return-to-play implications of immediate, evolving and repetitive brain injury are also considered, as are the emerging concept and possible implications of subconcussive injury.

Intracranial neuroenteric cysts: a concise review including an illustrative patient.

Neuroenteric cysts (NC) are rare, benign lesions lined by mucin-secreting cuboidal or columnar epithelium of an intestinal or respiratory type. They are regarded as ectopic endodermal cysts, and tend to be found in the spine rather than an intracranial location. Advances in neuroimaging have led to an increased frequency of diagnosis of NC, especially as an incidental finding, although such cysts may be confused radiologically with other lesions such as epidermoid and arachnoid cysts. We undertook a PubMed search of the literature using the search terms "neuroenteric cyst" and its many pseudonyms, including "endodermal cyst", "enterogenous cyst", "neurenteric cyst", "epithelial cyst", "intestinome", "teratomatous cyst", "gastrocytoma", and also "enterogenic", "foregut", "respiratory", and "bronchogenic cyst". Only reports in English and those containing histopathologically-confirmed NC were considered for this review. In total, 140 patients with intracranial NC were found, including the patient reported in the present review. This review describes the classification, epidemiology, embryology, clinical presentation, radiology, histopathology, and surgical treatment of NC, and includes an illustrative patient.