A guide to interpreting systematic reviews and meta-analyses in neurosurgery and surgery.

INTRODUCTION: Systematic reviews (SRs) and meta-analyses (MAs) are methods of data analysis used to synthesize information presented in multiple publications on the same topic. A thorough understanding of the steps involved in conducting this type of research and approaches to data analysis is critical for appropriate understanding, interpretation, and application of the findings of these reviews. METHODS: We reviewed reference texts in clinical neuroepidemiology, neurostatistics and research methods and other previously related articles on meta-analyses (MAs) in surgery. Based on existing theories and models and our cumulative years of expertise in conducting MAs, we have synthesized and presented a detailed pragmatic approach to interpreting MAs in Neurosurgery. RESULTS: Herein we have briefly defined SRs sand MAs and related terminologies, succinctly outlined the essential steps to conduct and critically appraise SRs and MAs. A practical approach to interpreting MAs for neurosurgeons is described in details. Based on summary outcome measures, we have used hypothetical examples to illustrate the Interpretation of the three commonest types of MAs in neurosurgery: MAs of Binary Outcome Measures (Pairwise MAs), MAs of proportions and MAs of Continuous Variables. Furthermore, we have elucidated on the concepts of heterogeneity, modeling, certainty, and bias essential for the robust and transparent interpretation of MAs. The basics for the Interpretation of Forest plots, the preferred graphical display of data in MAs are summarized. Additionally, a condensation of the assessment of the overall quality of methodology and reporting of MA and the applicability of evidence to patient care is presented. CONCLUSION: There is a paucity of pragmatic guides to appraise MAs for surgeons who are non-statisticians. This article serves as a detailed guide for the interpretation of systematic reviews and meta-analyses with examples of applications for clinical neurosurgeons.

Medications and "Risk" of Aneurysm Rupture Based on Presentation: Setting the Record Straight.

OBJECTIVE: Studies assessing aneurysm rupture "risk" based on comparative retrospective analyses of medications taken on presentation may be subject to presentation bias. Are patients with ruptured aneurysms simply less likely to be taking medications than those with unruptured aneurysms? METHODS: A retrospective chart review was conducted among patients with treated aneurysms from June 2016 to July 2023. A step-wise comparison of demographics, clinical characteristics (rupture status), and medications taken upon presentation was performed between ruptured and unruptured cases. RESULTS: One thousand three hundred eleven patients with intracranial aneurysms were included. The majority of patients presenting with ruptured aneurysms took no medications (68%), in contrast to 22% with unruptured aneurysms (P < 0.001). The majority of patients with unruptured aneurysms took 2-5 medications (51%), in contrast to 15% of patients with ruptured aneurysms taking 2-5 medications (P < 0.001). Twelve percent of patients with unruptured aneurysms took more than 5 medications, while only 1% with ruptured aneurysms did (P < 0.001). Thirty-five different medications were associated with unruptured presentation, including all evaluated antiplatelet agents, anti-hypertensives, antacids, pulmonary inhalers, and psychiatric medications (P < 0.05); no medications were associated with rupture on presentation. CONCLUSIONS: One cannot derive conclusions about medications and "risk" of rupture based on analyses at the time of presentation. This study identifies 35 different medications that were statistically significant and associated with an unruptured presentation; it is doubtful that each is "protective" against aneurysm rupture.

Impact of Embolisate Penetration, Type, and Technique on Results After Standalone Middle Meningeal Artery Embolization for Chronic Subdural Hematoma.

BACKGROUND AND OBJECTIVES: Middle meningeal artery embolization (MMAE) has emerged as a promising modality for chronic/subacute subdural hematoma treatment; however, consensus regarding embolization technique and embolisate has not been achieved. We thus sought to compare the efficacy of distinct MMAE techniques and embolisate. METHODS: An institutional registry was reviewed to identify patients undergoing standalone MMAE for symptomatic chronic/subacute subdural hematoma. Surgical rescue rate and time preceding 50% hematoma resolution were evaluated across 3 technical groups: aggressive penetration (AP), nonaggressive penetration with proximal coil embolization (NP-PC), and nonaggressive penetration alone (NP). Effect sizes were adjusted for demographic, neurological and radiological features through multivariable logistic and Cox regression. RESULTS: Among 117 procedures, 33.3% achieved AP, 36.8% had NP-PC, and 29.9% had NP. The rate of surgical rescue was 2.6% after AP, 9.3% for NP-PC, and 11.4% for NP. In patients not undergoing rescue surgery, 82.4% achieved hematoma resolution ≥50% at a median imaging follow-up of 56 days; AP or NP-PC were each statistically significantly associated with enhanced hematoma resolution as compared with NP (P = .02). Similarly, sensitivity analysis within medium-size hematoma and antiplatelet/anticoagulation-at-admission subgroups revealed a superiority of resolution after AP or NP-PC. A unique, comparative secondary analysis of liquid embolisate (Onyx vs n-butyl cyanoacrylate) revealed no impact on rate of surgical rescue or hematoma resolution. CONCLUSION: AP was associated with the lowest rate of surgical rescue, while both AP and NP-PC were associated with improved rates of hematoma resolution.

Traumatic Cerebral Venous Sinus Thrombosis: Management and Outcomes.

BACKGROUND: Traumatic brain injury (TBI) with skull fractures parallel to or crossing venous sinuses is a recognized risk factor for traumatic cerebral venous sinus thrombosis (tCVST). Despite the recognition of this traumatic pathology in the literature, no consensus regarding management has been achieved. This study aimed to evaluate the impact of tCVST on TBI outcomes and related complications. METHODS: Patients within a prospective registry at a level I trauma center from 2014 to 2023 were reviewed to identify tCVST cases. The impact of tCVST presence on Glasgow Outcome Scale scores at 6 months, 30-day mortality, and hospital length of stay were evaluated in multivariable-adjusted analyses. RESULTS: Among 607 patients with TBI, 61 patients were identified with skull fractures extending to the vicinity of venous sinuses with dedicated venography. Twenty-eight of these 61 patients (44.3%) had tCVST. The majority (96.4%) of tCVST were located in a unilateral transverse or sigmoid sinus. Complete recanalization was observed in 28% of patients on follow-up imaging (7/25 with follow-up imaging). None of the 28 patients suffered attributable venous infarcts or thrombus propagation. In the adjusted analysis, there was no difference in the 30-day mortality or Glasgow Outcome Scale at 6 months between patients with and without tCVST. CONCLUSIONS: Unilateral tCVST follows a benign clinical course without associated increased mortality or morbidity. The management of tCVST should be distinct as compared to spontaneous CVST, likely without the need for anticoagulation.

Anatomical Study of the Supratentorial Extension for the Retrolabyrinthine Presigmoid Approaches.

BACKGROUND: Supratentorial craniotomy represents the upper part of the combined trans-tentorial or the supra-infratentorial presigmoid approach. In this study, we provide qualitative and quantitative analyses for the supratentorial extension of the presigmoid retrolabyrinthine suprameatal approach (PRSA). METHODS: The infratentorial PRSA followed by the supratentorial extension craniotomy with dividing and removal of the tentorial strip were performed on both sides of 5 injected human cadaver heads (n = 10 sides). Quantitative analysis was performed for the surface area gained (surgical accessibility) by adding the supratentorial craniotomy. Qualitative analysis was performed for the parts of the brainstem, cranial nerves, and vascular structures that became accessible by adding the supratentorial craniotomy. The anatomical obstacles encountered in the added operative corridor were analyzed. RESULTS: The supratentorial extension of PRSA provides an increase in surgical accessibility of 102.65% as compared to the PRSA standalone. The mean surface area of the exposed brainstem is 197.98 (standard deviation: 76.222) and 401.209 (standard deviation: 123.96) for the infratentorial and the combined supra-infratentorial presigmoid approach, respectively. Exposure for parts of III, IV, and V cranial nerves is added after the extension, and the surface area of the outer craniotomy defect has increased by 60.32%. Parts of the basilar, anterior inferior cerebellar, and superior cerebellar arteries are accessible after the supratentorial extension. CONCLUSIONS: The supratentorial extension of PRSA allows access to the supra-trigeminal area of the pons and the lower part of the midbrain. Considering this surgical accessibility and exposure significantly assists in planning such complex approaches while targeting central skull base lesions.

Developmental Venous Anomalies.

Developmental venous anomalies (DVAs) are the most common vascular malformation detected on intracranial cross-sectional imaging. They are generally benign lesions thought to drain normal parenchyma. Spontaneous hemorrhages attributed to DVAs are rare and should be ascribed to associated cerebral cavernous malformations, flow-related shunts, or venous outflow obstruction. Contrast-enhanced MRI, susceptibility-weighted imaging, and high-field MRI are ideal tools for visualizing vessel connectivity and associated lesions. DVAs are not generally considered targets for treatment. Preservation of DVAs is an established practice in the microsurgical or radiosurgical treatment of associated lesions.

Cortical incisions and transcortical approaches for intra-axial and intraventricular lesions: A scoping review.

Background: Transcortical approaches, encompassing various surgical corridors, have been employed to treat an array of intraparenchymal or intraventricular brain pathologies, including tumors, vascular malformations, infections, intracerebral hematomas, and epileptic surgery. Designing cortical incisions relies on the lesion location and characteristics, knowledge of eloquent functional anatomy, and advanced imaging such as tractography. Despite their widespread use in neurosurgery, there is a noticeable lack of systematic studies examining their common lobe access points, associated complications, and prevalent pathologies. This scoping review assesses current evidence to guide the selection of transcortical approaches for treating a variety of intracranial pathologies. Methods: A scoping review was conducted using the PRISMA-ScR guidelines, searching PubMed, EMBASE, Scopus, and Web of Science. Studies were included if ≥5 patients operated on using transcortical approaches, with reported data on clinical features, treatments, and outcomes. Data analysis and synthesis were performed. Results: A total of 50 articles encompassing 2604 patients were included in the study. The most common primary pathology was brain tumors (60.6%), particularly gliomas (87.4%). The transcortical-transtemporal approach was the most frequently identified cortical approach (70.48%), and the temporal lobe was the most accessed brain lobe (55.68%). The postoperative course outcomes were reported as good (55.52%), poor (28.38%), and death (14.62%). Conclusion: Transcortical approaches are crucial techniques for managing a wide range of intracranial lesions, with the transcortical-transtemporal approach being the most common. According to the current literature, the selective choice of cortical incision and surgical corridor based on the lesion's pathology and anatomic-functional location correlates with acceptable functional outcomes.

Neurosurgery and Social Media: A Bibliometric Analysis of Scientific Production from 2004 to 2023.

BACKGROUND: Neurosurgery is a rapidly advancing surgical specialty. Social media has significantly impacted the landscape of advancements in the field of neurosurgery. Research on the subject of neurosurgery and social media plays a vital role in combating disability and mortality due to neurological diseases, especially in trauma-affected individuals by increasing cooperation and sharing of clinical experiences between neurosurgeons via social media. This study aimed to evaluate the global neurosurgery and social media research performance from 2004 to 2023. METHODS: All the data for neurosurgery and social media-related research publications from 2004 to 2023 were extracted from the Web of Science database and a comprehensive analysis was performed on the R-bibliometrix package. RESULTS: An increasing number of publications with an annual growth rate of 22.04% was observed, with >91% of total articles published in the last decade. The United States, the United Kingdom, Italy, France, Canada, and India made up of more than 67% of the global contribution. Out of 1449 authors, Chaurasia B was the most productive with 14 publications and the most globally cited document was JEAN WC, 2020 with 117 citations. The University of Cambridge was the leading institutional affiliation. World Neurosurgery was the most productive with >60 articles. CONCLUSIONS: Exploring neurosurgery on social media enhances global collaboration, utilizing dynamic platforms for real-time knowledge exchange and holds immense potential for the field's global advancement.

Mapping the circle of Trolard: A holistic view of its role in neurosurgical practice, anatomical perspectives and clinical applications.

Introduction: An anatomical structure that resembles the circle of Willis, the circle of Trolard is generated in the basal cistern and travels around the midbrain in a roundabout manner, passing adjacent to the lateral side of the cerebral peduncle. Research question: The primary objective of this article is to provide neurosurgeons with a comprehensive understanding of Trolard's circle, emphasizing its anatomical features and clinical significance. Material and methods: A comprehensive evaluation of the available literature pertaining to the venous circle of Trolard was conducted by conducting searches in the PubMed, Web of Science, and Scopus databases. In the present overview, the terminologies "venous circle of Trolard," "basal venous circle," and "basal vein of Rosenthal" were employed. Results: Upon doing a comprehensive examination of the existing literature and primary sources pertaining to the venous circle of Trolard, it was discovered that an only six studies had been conducted on this particular subject matter. We made observations regarding the anatomical characteristics of the subject and engaged in a discussion regarding their prospective applications and importance within the context of neurosurgical procedures. Discussion and conclusion: The scarcity of research on these structures is attributed to the challenges associated in studying them in vivo. Through directing focus towards these structures, our aim is to stimulate further investigation into their potential involvement in a range of neurological and neurosurgical disorders.

A case that encapsulates the challenges of being a neurosurgeon in war-torn countries: Perspectives from Iraq.

Background: The provision of healthcare services in Iraq has been negatively affected by a lack of resources, strained healthcare infrastructure, and low patient socioeconomic status. This paper describes a case of multiple intracranial aneurysms (MIAs) that highlight the challenges of practicing vascular neurosurgery in Iraq. Case Description: A 57-year-old female presented with sudden-onset severe headache, photophobia, and drowsiness and was diagnosed with subarachnoid hemorrhage in the basal cistern. Despite international guidelines recommending urgent treatment for suspected ruptured intracranial aneurysms, the patient's healthcare team in Babylon advised against a CT angiogram (CTA). The patient's family took responsibility for transferring her to a private facility for a CTA, which showed four aneurysms. Due to financial constraints, the family opted for open surgery, during which a ruptured aneurysm was found and successfully managed. The remaining two aneurysms were monitored with serial follow-up imaging. Conclusion: The case highlights the challenges of practicing vascular neurosurgery in Iraq and the impact of financial constraints on the management of MIA. It emphasizes the need for increased resources and expertise in the country's healthcare system to provide optimal care for patients with life-threatening conditions.

A Systematic Review and Meta-Analysis of 3-Dimensional Morphometric Parameters for Cerebral Aneurysms.

BACKGROUND: Imaging modalities with increased spatial resolution have allowed for more precise quantification of cerebral aneurysm shape in 3-dimensional (3D) space. We conducted a systematic review and meta-analysis to assess the correlation of individual 3D morphometric measures with cerebral aneurysm rupture status. METHODS: Two independent reviewers performed a PRISMA (preferred reporting items of systematic reviews and meta-analysis)-guided literature search to identify articles reporting the association between 3D morphometric measures of intracranial aneurysms and rupture status. RESULTS: A total of 15,122 articles were identified. After screening, 39 studies were included. We identified 17 3D morphometric measures, with 11 eligible for the meta-analysis. The meta-analysis showed a significant association with rupture status for the following measures: nonsphericity index (standardized mean difference [SMD], 0.66; 95% confidence interval [CI], 0.53-0.79; P < 0.0001; I2 = 55.2%), undulation index (SMD, 0.55; 95% CI, 0.26-0.85; P = 0.0017; I2 = 68.1%), ellipticity index (SMD, 0.53; 95% CI, 0.29-0.77; P = 0.0005; I2 = 70.8%), volume (SMD, 0.18; 95% CI, 0.02-0.35; P = 0.0320; I2 = 82.3%), volume/ostium ratio (SMD, 0.43; 95% CI, 0.16-0.71; P = 0.0075; I2 = 90.4%), elongation (SMD, -0.94; 95% CI, -1.12 to -0.76; P = 0.0005; I2 = 0%), flatness (SMD, -0.87; 95% CI, -1.04 to -0.71; P = 0.0005; I2 = 0%), and sphericity (SMD, -0.62; 95% CI, -1.06 to -0.17; P = 0.0215; I2 = 67.9%). A significant risk of publication bias was estimated for the ellipticity index (P = 0.0360) and volume (P = 0.0030). CONCLUSIONS: Based on the results of a meta-analysis containing 39 studies, the nonsphericity index, undulation index, elongation, flatness, and sphericity demonstrated the most consistent correlation with rupture status.

Flow Diverters with Surface Modification in Patients with Intracranial Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND: Flow diverters with surface modification (FDSM) are increasingly being used in the treatment of intracranial aneurysms (ANs). We aimed to evaluate the effectiveness and safety across different devices and antiplatelet therapies using a systematic review and meta-analysis. METHODS: A systematic review was performed to identify original studies of ≥10 patients with intracranial ANs treated with FDSM from database inception through August 2023. Primary effectiveness outcome was the rate of complete AN occlusion at follow-up ≥6 months. Safety outcomes included ischemic stroke, hemorrhage, and in-stent thrombosis, and were stratified by FDSM devices and antiplatelet therapies. Certainty of evidence was evaluated following the Grading of Recommendations, Assessment, Development, and Evaluations approach. RESULTS: Twenty-seven studies were included, yielding 2161 patients with 2373 ANs. A total of 70.5% of the ANs were located on the internal carotid artery (ICA). Total 10.3% were acutely ruptured. The complete AN occlusion rate was 72.3% at follow-up ≥6 months. Sensitivity analysis in the ICA AN cohort yielded comparable occlusion rates between Pipeline Flex Embolization Device-Shield (80.4%) and Phenox-hydrophilic polymer-coated (77.5%, P = 0.54), but a lower 66.2% rate for Flow Redirection Endoluminal Device-X (P = 0.02). The rate of in-stent thrombosis and stenosis tended to be higher in Phenox-hydrophilic polymer-coated (3.4%) and Flow Redirection Endoluminal Device-X (4.3%) versus Pipeline Flex Embolization Device-Shield (0.8%, P = 0.05). CONCLUSIONS: FDSM were safe with satisfactory effectiveness for intracranial ANs. More specific investigations are warranted to explore their performance in ANs beyond the ICA and optimal antiplatelet therapy.

Surgical resection of pericallosal tuberculoma through contralateral approach: A case report.

Background: Pericallosal tuberculoma, a rare form of intracranial tuberculoma, affects the corpus callosum and results from tuberculosis (TB), a bacterial infection that can cause a myriad of symptoms. Diagnosing this condition can be challenging but can be confirmed through imaging studies and biopsy. Treatment involves a combination of antitubercular medications and surgical removal of the lesion if it is in a critical location or causing significant symptoms. This article describes the surgical management and imaging characteristics approach to a patient with intracranial tuberculoma. Case Description: A 17-year-old female with a history of TB meningitis nine years ago presented with one week of recurrent seizures and mild third nerve palsy, later diagnosed as a tuberculoma of the corpus callosum through radiological imaging and biopsies. A total surgical resection of the lesion was performed using a contralateral interhemispheric frontal parasagittal approach. The patient went under observation and suitable follow-up plans. Conclusion: Surgical management can effectively treat cerebral granulomas and improve neurological deficits in patients with recurring TB. Despite the possibility of complications, the benefits of such measures are highlighted in this case, suggesting that surgical intervention can be a viable option for achieving optimal outcomes in these patients.

Occipital artery: Anatomical variations and neurosurgical applications.

Background: The occipital artery (OA) is a branch of the external carotid artery. It gives rise to several cutaneous, muscular, and meningeal branches to supply different anatomical areas. The implication of OA in the neurosurgical field is well-established in the literature. Our aim in this study is to draw a complete picture of the anatomical variations and neurosurgical applications of the OA. Methods: A literature review was conducted in Google Scholar and PubMed to review the studies discussing OA, its anatomical variation, and neurosurgical applications. Results: We identified 29 articles that discuss the anatomical variations and neurosurgical applications of the OA. Certain variables are used to describe the surgical anatomy of OA. We also discussed certain applications of OA and its importance in neurosurgical bypass, embolization, and aneurysms. Conclusion: Comprehending the anatomy of the OA is crucial for neurosurgeons to safely and effectively perform procedures such as bypass and embolization. In addition, knowledge of the anatomical variations of the OA can help surgeons anticipate potential challenges and tailor their approach accordingly.

Supraorbital artery: Anatomical variations and neurosurgical applications.

Background: The supraorbital artery (SOA) originates from the ophthalmic artery in a superomedial aspect of the orbit, exiting through the supraorbital groove to emerge onto the forehead. The SOA has important neurosurgical considerations regarding different approaches and bypasses. The SOA is poorly described in the standard anatomical textbooks. Therefore, we present this article to describe the anatomical variations of the SOA and their implications on the neurosurgical field. Methods: We conducted a literature review in PubMed and Google Scholar databases to review the existing literature describing the SOA anatomy and its neurosurgical applications. Results: While reading the available articles and original works regarding SOA, we identified 22 studies that discuss the SOA. We noticed the anatomical variations of the SOA in terms of origin, course, diameter, branches, depth, and distance in relation to the midline and vertical glabellar line. We also discussed certain applications of SOA and its importance in neurosurgical approaches, bypass, photoplethysmography, aneurysms, and reconstruction of cranial fossa defects. Conclusion: The variable anatomy of the SOA has a paramount impact on performing different neurosurgical approaches. Therefore, cadaveric studies of the SOA are important to explore potential methods for the preservation of the artery in different neurosurgical applications.

The Enigma of the Impervious Nobel Prize for Neurosurgeons.

The Nobel Prize, which has been highly esteemed since its establishment in 1901, carries significant status within the scientific community. The Nobel Prize in Physics, Chemistry, Medicine, and Economics has long been recognized for its recognition of significant scientific contributions. However, the Nobel Prize in Physiology or Medicine holds a distinct significance due to its direct association with advancements in human health. The subject of neurosurgery, which encompasses both clinical and academic domains, has witnessed remarkable developments; nonetheless, it has not yet been awarded a Nobel Prize. The objective of this investigation is to elucidate the factors contributing to the enigmatic nature of this recognition and propose feasible techniques that can be implemented to achieve it.

Methods of Hemostasis in Cranial Neurosurgery: An Anatomy-Based Stepwise Review.

BACKGROUND: Hemostasis is crucial in preventing hemorrhage during cranial neurosurgical procedures and maintaining visualization of the surgical field. There is significant variation in the availability of hemostatic methods across different settings and hemostatic techniques are being continuously developed over the decades of practicing neurosurgery. The aim of this article is to provide an outline of the potential methods to achieve hemostasis based on the sequential operative anatomy of a cranial operation. METHODS: A systematic review was conducted following the PRISMA guidelines. The PubMed database was searched from inception of the database to July 18, 2023. A total of 64 studies were identified fulfilling predefined inclusion criteria, and the risk of bias was assessed using the Joanna Briggs Institute checklists. RESULTS: Seventy-one hemostatic agents, techniques, tools, and devices were identified, which were then categorized according to the operative phase for which they are indicated. Nine operative anatomic targets were addressed in the sequence in which they are involved during a cranial procedure. For each anatomic target, the following number of hemostatic techniques/agents were identified: 11 for scalp, 3 for periosteum, 10 for skull bone, 11 for dura mater, 9 for venous sinuses, 5 for arteries, 6 for veins, 12 for brain parenchyma, and 4 for cerebral ventricles. CONCLUSIONS: Depending on the phase of the surgery and the anatomic structure involved, the selection of the appropriate hemostatic method is determined by the source of bleeding. Surgeon awareness of all the potential techniques that can be applied to achieve hemostasis is paramount, especially when faced with operative nuances and difficult-to-control bleeding during cranial neurosurgical procedures.