Subarachnoid Haemorrhage Incidence Pattern Analysis with Circular Statistics.

Knowledge about biological rhythms of diseases may not only help in understanding the pathophysiology of diseases but can also help health service policy makers and emergency department directors to allocate resources efficiently. Aneurysmal subarachnoid haemorrhage (SAH) has high rates of morbidity and mortality. The incidence of SAH has been attributed to patient-related factors such as characteristics of aneurysms, smoking, and hypertension. There are studies showing that the incidence of aneurysmal SAH appears to behave in periodic fashions over long time periods. However, there are inconsistencies in the literature regarding the impact of chronobiological factors such as circadian, seasonal, and lunar cycle factors on the occurrence of SAH. In this study, we focused on the analysis of a temporal pattern of SAH (infradian rhythms) with a novel approach using circular statistical methods. We aimed to see whether there is a circular pattern for the occurrence of SAH at all and if so, whether it can be related to known temporal patterns based on available literature. Our study did not support the notion that aneurysmal subarachnoid haemorrhages occur on any specific day in a cycle with specific lengths up to 365 days including specific weekdays, full moon, equinoxes, and solstices. Hence, we found no relationship between SAH incidence and timing. Study in larger populations using similar circular statistical methods is suggested.

Neurosurgical literature classification - Evaluation of three automated methods and time trend analysis of the literature.

Background: Automated supervised text classification methods require preclassified training data. Their application in scenarios that a large amount of preclassified data is not accessible is challenging. Neurosurgical literature classification into subspecialties is an example of this situation. We have introduced an automated similarity-based text classification method, evaluated it along with two other automated methods and applied the introduced method in neurosurgical literature classification. Methods: Performance of an introduced similarity-based text classification method along with two other automated methods (Lbl2Vec and keyword counting-based methods) was compared with performance of two senior neurosurgery registrars in classification of neurosurgical literature to 5 subspecialties. The Kappa-statistic measure of interrater agreement, overall marginal homogeneity using the Stuart-Maxwell test, marginal homogeneity relative to individual categories using McNemar tests and the sensitivity and specificity of each of the three methods were calculated.The introduced method was used to classify 211617 neurosurgical publications indexed in Pubmed to different subspecialties based on keywords extracted from subspecialty sections of a neurosurgery textbook. Results: The introduced similarity-based method showed the highest agreement with the registrars (raw agreement and Kappa value) followed by the Lbl2Vec and the counting-based method. Classifications of the English neurosurgical publications indexed in Pubmed into categories of Oncology, Vascular, Spine and functional using the introduced similarity-based method were more reliable (closer to the registrars' classifications) than Cranial trauma. The classifications and future forecast showed highest publications in Oncology, followed by Cranial trauma, Vascular, spine and functional neurosurgery. Conclusion: The classification of the English neurosurgical publications indexed in Pubmed to different subspecialties, using the introduced method, shows that Oncology and tumour has been the main battleground for the neurosurgeons over years and probably in the near future. The performance of the introduced classification method in comparison with the human performance shows its potential application in the situations that enough preclassified data are not accessible for automated text classification.

Hemianopia: A complication of epidural injection in a patient with arachnoid cyst - case report.

Epidural injections are routinely used for short-term management of radicular pain and chronic low back pain. Prescription of this intervention, in the presence of intracranial abnormalities, is a topic of debate. Intracranial arachnoid cysts are cerebrospinal fluid-filled spaces, which are usually asymptomatic despite being a formidable size. As far as the authors know, there have been no cases depicted in indexed literature regarding asymptomatic supratentorial arachnoid cysts becoming symptomatic post undertaking of spinal epidural injections. We depict this phenomenon in a 53-year-old woman, who ultimately required a craniotomy to address their symptoms. Asymptomatic supratentorial arachnoid cysts can become symptomatic post undertaking of spinal epidural injections. In cases of known cranial arachnoid cysts with mass effect, the small risk that the cranial arachnoid cyst may become symptomatic during or after epidural injections should be a consideration and the patients should be informed of the potential associated risks.

Significant Disparity of Access to Stroke Treatment Between the Western Parts and Eastern and Northern Parts of Sydney.

Objective To provide an estimate of access times and distances to an endovascular clot retrieval (ECR) service provider for a typical stroke patient in the western part of Sydney and to compare it with the eastern and northern parts. Methods Incidences of stroke were simulated through a population-weighted randomized selection of addresses in the studied western, eastern, and northern areas of Sydney (100,000 times for each). The access times and distances were calculated from those addresses to the closest ECR hub for the eastern and northern parts and to all five ECR hubs, as well as the Nepean Public Hospital (NPH) for the western part. The access times and distance means were compared statistically using ANOVA. Results In the western areas, the estimated average access times and distances to different ECR hubs varied from 38.5 (+/- 15) to 45 (+/- 15) minutes and from 42 (+/- 15.9) to 46.8 (+/- 16) km in working hours and from 45 (+/- 15) to 64 (+/- 15) minutes and 46.8 (+/- 16) to 69.6 (+/- 16) km in after hours. However, the estimated average access times and distances to the local ECR hub were 12.25 (+/- 6) minutes and 9.1 (+/- 5.6) km for northern and 7.5 (+/- 4) minutes and 4.4 (+/- 2.5) km for the eastern areas. The differences between the estimated average access times and distances for a typical stroke patient to an ECR hub in the western areas in comparison with eastern or northern areas were statistically significant (p<0.0001). The average access times and distances in the western part to NPH were 17 (+/- 16) minutes and 15.6 (+/- 16.6) km. Conclusions The patients in the western part of Sydney had significantly longer access times to ECR hubs than those living in comparable areas of the eastern and northern parts. This study supports the Nepean Public Hospital supplying an ECR service to achieve travel times, and, therefore, treatment times for a typical stroke patient in the western parts, similar to patients in the eastern and northern parts of Sydney.

Optimal Temperature of Irrigation Fluid for Hemostasis in Neurosurgery: A Narrative Literature Review.

BACKGROUND: Hemostasis in neurosurgery is crucial to patient and surgery outcomes, with many techniques developed for this. One area that is not appropriately characterized despite continuous anecdotal evidence the temperature of the irrigation fluid (IF) used and its effects on stemming hemorrhages. Given the ubiquitous use of IF in neurosurgery for clearing blood from the surgical field, it is important to explore its role as a hemostat and whether or not the temperature of the IF influences its hemostatic capacity. This review explored the literature for an optimal IF temperature for hemostasis in neurosurgery. METHODS: Database searches were conducted using MEDLINE, Scopus, Web of Science, and CINAHL, with citation chaining occurring where applicable. Standard terms around neurosurgery, hemostasis, and irrigation were used. RESULTS: Seven articles were identified. No optimal temperature for hemostasis could be confidently synthesized from the literature owing to lack of primary investigation on the subject. After collating available information into common themes, it is suggested that that temperatures >38°C are preferred. CONCLUSION: The literature in this area is limited. Despite a lack of applicable systematic investigation on the topic, by exploring the physiology of hemostasis and IF, best practice guidelines for IF, and the literature on the role of the temperature of IF in other surgical specialties, it is suggested that a temperature in the range of 38 to 40°C would be most applicable to a value optimal for neurosurgery.

An Ocular Chameleon.

Patients presenting with transient visual loss is common in emergency departments. Neurologists, ophthalmologists and emergency care physicians may be called upon to evaluate such patients. Monocular visual loss should be differentiated from the binocular involvement as the oetologies, investigations and management of such patients differ considerably. We report a case of monocular visual loss that involved predominantly one eye but affected the other side independently, albeit less frequently. A meticulous history, thorough general, neurological and ophthalmological examinations are necessary in such patients to identify the cause and to treat appropriately. Ocular ischemic syndrome (OIS) is due to chronic hypoperfusion of the structures supplied by ophthalmic artery leading to monocular visual loss. Stenosis of the ipsilateral internal carotid artery from a variety of causes is the main underlying mechanism. The first case of OIS was reported by Hedges in 1963 and the term was coined later by Barry and Magargal. Ocular ischemic syndrome is an important differential diagnosis to consider especially in older people and those with vascular risk factors. An overview of important differential diagnosis, clinical features and treatment of OIC are discussed in this article. A multidisciplinary team is optimal for the management of ocular ischemic syndrome.

A Simple Retractor for Anterior Cervical Diskectomy.

BACKGROUND: The insertion of available cervical retractor systems is relatively complex for the limited exposure required for single-level anterior cervical diskectomy. OBJECTIVE: To introduce a novel cervical retractor system and report the initial experience of its application. METHODS: A simple retractor system was designed that is fixed to the vertebral body through Caspar pins. The design allows the retractor to move with the vertebrae during distraction via the traditional Caspar distractor system. The advantages and limitations of the device based on the initial experience are discussed. RESULTS: The author has used the current version of the retractor on 32 single-level anterior cervical diskectomies. The insertion of the retractor is easy, and its application provides safe and satisfactory anterior cervical exposure. There have not been related complications, although transient dysphagia has not been prevented. CONCLUSION: This newly designed retractor system is simple and efficient for a single-level anterior cervical diskectomy, and its insertion is relatively easy.

Virtual Reality Angiogram vs 3-Dimensional Printed Angiogram as an Educational tool-A Comparative Study.

BACKGROUND: Three-dimensional (3D) visualization of the neurovascular structures has helped preoperative surgical planning. 3D printed models and virtual reality (VR) devices are 2 options to improve 3D stereovision and stereoscopic depth perception of cerebrovascular anatomy for aneurysm surgery. OBJECTIVE: To investigate and compare the practicality and potential of 3D printed and VR models in a neurosurgical education context. METHODS: The VR angiogram was introduced through the development and testing of a VR smartphone app. Ten neurosurgical trainees from Australia and New Zealand participated in a 2-part interactive exercise using 3 3D printed and VR angiogram models followed by a questionnaire about their experience. In a separate exercise to investigate the learning curve effect on VR angiogram application, a qualified neurosurgeon was subjected to 15 exercises involving manipulating VR angiograms models. RESULTS: VR angiogram outperformed 3D printed model in terms of resolution. It had statistically significant advantage in ability to zoom, resolution, ease of manipulation, model durability, and educational potential. VR angiogram had a higher questionnaire total score than 3D models. The 3D printed models had a statistically significant advantage in depth perception and ease of manipulation. The results were independent of trainee year level, sequence of the tests, or anatomy. CONCLUSION: In selected cases with challenging cerebrovascular anatomy where stereoscopic depth perception is helpful, VR angiogram should be considered as a viable alternative to the 3D printed models for neurosurgical training and preoperative planning. An immersive virtual environment offers excellent resolution and ability to zoom, potentiating it as an untapped educational tool.

Results of Surgery for Low-Grade Brain Arteriovenous Malformation Resection by Early Career Neurosurgeons: An Observational Study.

BACKGROUND: For sustainability of arteriovenous malformation (AVM) surgery, results from early career cerebrovascular neurosurgeons (ECCNs) must be acceptably safe. OBJECTIVE: To determine whether ECCNs performance of Spetzler-Ponce Class A AVM (SPC A) resection can be acceptably safe. METHODS: ECCNs completing a cerebrovascular fellowship (2004-2015) with the last author were included. Inclusion of the ECCN cases occurred if they: had a prospective database of all AVM cases since commencing independent practice; were the primary surgeon on SPC A; and had made the significant management decisions. All SPC A surgical cases from the beginning of the ECCN's independent surgical practice to a maximum of 8 yr were included. An adverse outcome was considered a complication of surgery leading to a new permanent neurological deficit with a last modified Rankin Scale score >1. A cumulative summation (Cusum) plot examined the performance of each surgery. The highest acceptable level of adverse outcomes for the Cusum was 3.3%, derived from the upper 95% confidence interval of the last author's reported series. RESULTS: Six ECCNs contributed 110 cases for analysis. The median number of SPC A cases operated by each ECCN was 16.5 (range 4-40). Preoperative embolization was performed in 5 (4.5%). The incidence of adverse outcomes was 1.8% (95% confidence interval: <0.01%-6.8%). At no point during the accumulated series did the combined cohort become unacceptable by the Cusum plot. CONCLUSION: ECCNs with appropriate training appointed to large-volume cerebrovascular centers can achieve results for surgery for SPC A that are not appreciably worse than those published from high-volume neurosurgeons.

Peritoneum as an origin of epilepsy from the viewpoint of Avicenna.

There are studies that show that the concepts of epilepsy have been rooted in Persian medicine; Avicenna "Ibn-e-Sina"-one of the great Persian physicians in the Islamic golden age (9th-12th century AD)-has considered some types of epilepsy with the association of the stomach, the spleen, the "Maraqq," and the whole body which has not been reviewed properly. These organs influence on the brain and can cause epilepsy. This article presents concept of Maraqq-related epilepsy; according to Avicenna's view, "Maraqq" is a membranous structure which is located in the abdomen (equivalent of parietal peritoneum in current nomenclature). We discuss his viewpoint about the diagnosis and treatment of Maraqq-related epilepsy with focus on herbal remedies. The concept of a relationship between the "Maraqq" and the brain is well discussed in the old Persian medicine texts; however, it seems that further studies in this area are required to clarify Avicenna's view about the pathophysiological mechanisms, clinical manifestations, and treatment strategies.

Smartphone as a Remote Touchpad to Facilitate Visualization of 3D Cerebral Angiograms during Aneurysm Surgery.

Background During aneurysm surgery, neurosurgeons may need to look at the cerebral angiograms again to better orient themselves to the aneurysm and also the surrounding vascular anatomy. Simplification of the intraoperative imaging review and reduction of the time interval between the view under the microscope and the angiogram review can theoretically improve orientation. Objective To describe the use of a smartphone as a remote touchpad to simplify intraoperative visualization of three-dimensional (3D) cerebral angiograms and reduce the time interval between the view under the microscope and the angiogram review. Methods Anonymized 3D angiograms of the patients in Virtual Reality Modelling Language format are securely uploaded to sketchfab.com, accessible through smartphone Web browsers. A simple software has been developed and made available to facilitate the workflow. The smartphone is connected wirelessly to an external monitor using a Chromecast device and is used intraoperatively as a remote touchpad to view/rotate/zoom the 3D aneurysms angiograms on the external monitor. Results Implementation of the method is practical and helpful for the surgeon in certain cases. It also helps the operating staff, registrars, and students to orient themselves to the surgical anatomy. I present 10 of the uploaded angiograms published online. Conclusion The concept and method of using the smartphone as a remote touchpad to improve intraoperative visualization of 3D cerebral angiograms is described. The implementation is practical, using easily available hardware and software, in most neurosurgical centers worldwide. The method and concept have potential for further development.

Pharmacokinetic Behavior of Phenytoin in Head Trauma and Cerebrovascular Accident Patients in an Iranian Population.

OBJECTIVE: Acute brain injury is one of the leading causes of morbidity and mortality worldwide. Phenytoin has been commonly used as an anticonvulsant agent for the treatment or prophylaxis of seizures following acute brain injury. After a severe head injury, several pharmacokinetic changes occur. The aim of this study is the comparative evaluation of phenytoin serum concentration in patients with traumatic and nontraumatic brain injury (TBI). METHODS: This prospective observational study was performed on twenty adult brain injury patients who were admitted to an Intensive Care Unit and required phenytoin for the treatment or prophylaxis of postinjury seizures. For all the patients, phenytoin serum concentration was determined in three scheduled time points. Phenytoin serum concentration and pharmacokinetic parameters were compared between patients with TBI and cerebrovascular accident (CVA). FINDINGS: The Vmaxand Kmwere significantly higher in head trauma (HT) patients than the CVA group. The phenytoin concentration (Cp) and the Cp/dose ratio were significantly higher in the CVA group patients during the first sampling (P < 0.05). The Acute Physiology and Chronic Health Evaluation П (APACHE П) score was significantly lower than the baseline at the end of the study in each group of patients (P < 0.05). In addition, no significant correlation was observed between Vmax, Km, Cp, Cp/dose ratio, and APACHE II scores at the time of sampling. CONCLUSION: Due to significant differences in phenytoin plasma concentration and pharmacokinetic parameters between HT and CVA patients, close attention must be paid to the pharmacokinetic behavior of phenytoin in the efforts to improve the patient's outcome after a severe HT.

App-assisted external ventricular drain insertion.

The freehand technique for insertion of an external ventricular drain (EVD) is based on fixed anatomical landmarks and does not take individual variations into consideration. A patient-tailored approach based on augmented-reality techniques using devices such as smartphones can address this shortcoming. The Sina neurosurgical assist (Sina) is an Android mobile device application (app) that was designed and developed to be used as a simple intraoperative neurosurgical planning aid. It overlaps the patient's images from previously performed CT or MRI studies on the image seen through the device camera. The device is held by an assistant who aligns the images and provides information about the relative position of the target and EVD to the surgeon who is performing EVD insertion. This app can be used to provide guidance and continuous monitoring during EVD placement. The author describes the technique of Sina-assisted EVD insertion into the frontal horn of the lateral ventricle and reports on its clinical application in 5 cases as well as the results of ex vivo studies of ease of use and precision. The technique has potential for further development and use with other augmented-reality devices.