Ensuring Neurosurgical Equity: Setup for Safe Ventricular Endoscopy and Predictors of Clinical Outcome in a Resource-Limited Health Care System.

BACKGROUND: Neuroendoscopic surgeries require specialized equipment, which may not be universally available or equitably distributed in most neurosurgical units of resource-limited healthcare systems. This review reports on the use of locally available resources to perform safe ventricular endoscopic surgeries in patients with hydrocephalus and cystic craniopharyngioma in a resource-limited healthcare system. METHODS: This study described the use of locally available resources to perform intraventricular endoscopic surgeries and retrospectively reviewed a 3-year outcome of these surgeries. A 24F, 2-way Foley catheter was used as an endoscopic working sheet. A transparent 9-mm nasotracheal tube served as a retractor and a peel-away sheath. An intravenous fluid administration set was used for irrigation. Finally, a metallic stylet of an external ventricular drain was used for third ventricular floor or cyst wall fenestration. RESULTS: There were 21 intraventricular endoscopic surgeries performed consisting of endoscopic third ventriculostomy (ETV), septostomy, cystostomy, and intraventricular biopsy. Four patients died, with 1 death directly related to intraoperative hemorrhage. Most (3/21) of the complications were postoperative cerebrospinal fluid leakage and partial wound dehiscence. Of the 17 surviving patients, the ETV success rate was 82.4% (14/17). Logistic regression analysis revealed that patient age, etiology, Endoscopic Third Ventriculostomy Success Score, and procedure performed were not predictive of ETV success or mortality. CONCLUSIONS: Patients accessing neurosurgical care in resource-limited healthcare systems can benefit from safe and successful intraventricular endoscopy. However, this may require the innovative use of locally available resources that can be adapted to local neurosurgical needs.

Global Neurosurgery: An Overview.

In the following article, we define the practice of global neurosurgery and review the major historical events defining this movement within the larger context of global surgery. The current state of the neurosurgical workforce, disease burden, and ongoing collaborative efforts are highlighted. Ethical practice leading the sustainability is discussed, as well as future targets for the global community as we look beyond the next decade of opportunities to affect the neurosurgical burden of disease.

Achieving Equity Through Global Neurosurgery Research.

Since the release of the Lancet Commission on Global Surgery report in 2015, there has been an increase in the number of published papers on global neurosurgery, gaining widespread support from major neurosurgery journals. However, there remains no consensus on what may be considered part of global neurosurgery literature. Here, we propose that global neurosurgery research encompasses all scholarly work that measure, explore, or address inequity in the care of neurosurgical disease. We describe the growth of global neurosurgery research, cite landmark papers, and discuss barriers to participation, particularly among neurosurgeons in low- and middle-income countries. We introduce the 3Rs framework, advocating for global neurosurgery research that is rigorous, responsive, and responsible. This narrative review aims to guide young neurosurgeons and other researchers interested in the field, and to provide a framework through which global neurosurgery practitioners and advocates can evaluate previously accomplished work, paving the way toward neurosurgery that is timely, safe, and affordable to all.

Education and Training in Global Neurosurgery: The Quest for Diversity and Equitable Collaborations.

Education and training are essential components of global neurosurgery because they provide a sustainable solution to address the workforce deficits in the neurosurgical burden of disease. Neurosurgery training programs and opportunities exist in most areas of the world, but some countries still lack formal mechanisms to train future generations. In this special article, we review the neurosurgical workforce deficit, characterize factors influencing the absence or inadequacy of neurosurgical training, and identify strategies that could facilitate global efforts in building a stronger workforce. We summarize the key neurosurgical training models worldwide and the factors influencing the standardization of neurosurgical education by region. In addition, we evaluate the "brain drain" issue in the larger context of the healthcare workforce and propose solutions to mitigate this phenomenon in neurosurgical practice. Future generations of neurosurgical trainees depend on our efforts to intensify and expand education and training in this new virtual era. As we look to the future, we must prioritize education to strengthen the future neurosurgeons who will lead and shape the frontiers of our field.

Pediatric brain tumors in sub-Saharan Africa: a systematic review and meta-analysis.

OBJECTIVE: Brain tumors are a global problem, leading to higher cancer-related morbidity and mortality rates in children. Despite the progressive though slow advances in neuro-oncology care, research, and diagnostics in sub-Saharan Africa (SSA), the epidemiological landscape of pediatric brain tumors (PBTs) remains underestimated. This study aimed to systematically analyze the distribution of PBT types in SSA. METHODS: Ovid Medline, Global Index Medicus, African Journals Online, Google Scholar, and faculty of medicine libraries were searched for literature on PBTs in SSA published before October 29, 2022. A proportional meta-analysis was performed. RESULTS: Forty-nine studies, involving 2360 children, met the inclusion criteria for review; only 20 (40.82%) were included in the quantitative analysis. South Africa and Nigeria were the countries with the most abundant data. Glioma not otherwise specified (NOS) was the common PBT in the 4 SSA regions combined. However, medulloblastoma was more commonly reported in Southern SSA (p = 0.01) than in other regions. The prevalence and the overall pooled proportion of the 3 common PBTs was estimated at 46.27% and 0.41 (95% CI 0.32-0.50, 95% prediction interval [PI] 0.11-0.79), 25.34% and 0.18 (95% CI 0.14-0.21, 95% PI 0.06-0.40), and 12.67% and 0.12 (95% CI 0.09-0.15, 95% PI 0.04-0.29) for glioma NOS, medulloblastoma, and craniopharyngioma, respectively. Sample size moderated the estimated proportion of glioma NOS (p = 0.02). The highest proportion of craniopharyngiomas was in Western SSA, and medulloblastoma and glioma NOS in Central SSA. CONCLUSIONS: These findings provide insight into the trends of PBT types and the proportion of the top 3 most common tumors across SSA. Although statistical conclusions are difficult due to the inconsistency in the data, the study identifies critical areas for policy development and collaborations that can facilitate improved outcomes in PBTs in SSA. More accurate epidemiological studies of these tumors are needed to better understand the burden of the disease and the geographic variation in their distribution, and to raise awareness in their subsequent management.

The Impact of Colonialism on Surgical Training Structures in Africa Part 1: Contextualizing the Past, Present, and Future.

Since the first African country attained independence from colonial rule, surgical training on the continent has evolved along 3 principal models. The first is a colonial, local master-apprentice model, the second is a purely local training model, and the third is a collegiate intercountry model. The 3 models exist currently and there are varied perceptions of their relative merits in training competent neurosurgeons. We reviewed the historical development of training and in an accompanying study, seek to describe the complex array of surgical training pathways and explore the neocolonial underpinnings of how these various models of training impact today the development of surgical capacity in Africa. In addition, we sought to better understand how some training systems may contribute to the widely recognized "brain drain" of surgeons from the African continent to high income countries in Europe and North America. To date, there are no published studies evaluating the impact of surgical training systems on skilled workforce emigration out of Africa. This review aims to discover potentially addressable sources of improving healthcare and training equity in this region.

The influence of fixation and cryopreservation of cerebrospinal fluid on antigen expression and cell percentages by flow cytometric analysis.

The pauci-cellular nature of cerebrospinal (CSF), particularly ventricular CSF, and the rapid cell death following sampling, incumbers the use of flow cytometric analysis of these samples in the investigation of central nervous system (CNS) pathologies. Developing a method that allows long-term storage and batched analysis of CSF samples without compromising cell integrity is highly desirable in clinical research, given that CSF is often sampled after hours creating logistical difficulties for fresh processing. We examined percentages and relative proportion of peripheral and brain-derived immune cells in cryopreserved and transfix-treated CSF, compared to freshly processed CSF. Cell proportions were more comparable between Fresh and Cryopreserved CSF (mean of differences = 3.19), than between fresh and transfix-treated CSF (mean of differences = 14.82). No significant differences in cell percentages were observed in fresh versus cryopreserved CSF; however significantly lower cell percentages were observed in transfix-treated CSF compared to Fresh CSF [(CD11b++ (p = 0.01), CD4+ (p = 0.001), CD8+ (p = 0.007), NK cells (p = 0.04), as well as CD69+ activation marker (p = 0.001)]. Furthermore, loss of marker expression of various lymphocyte sub-populations were observed in transfix-treated CSF. Cryopreservation is a feasible option for long-term storage of ventricular CSF and allows accurate immunophenotyping of peripheral and brain-derived cell populations by flow cytometry.

The Impact of Colonialism on Surgical Training Structures In Africa Part 2: Surveying Current and Past Trainees.

BACKGROUND: As a result of gradual independence from colonial rule over the course of the past century, Africa has developed and evolved 3 primary surgical training structures: an extracontinental colonial model, an intracontinental college-based model, and several smaller national or local models. There is consistent evidence of international brain drain of surgical trainees and an unequal continental distribution of surgeons; however there has not, to date, been an evaluation of the impact colonialism on the evolution of surgical training on the continent. This study aims to identify the etiologies and consequences of this segmentation of surgical training in Africa. METHODS: This is a cross-sectional survey of the experience and perspectives of surgical training by current African trainees and graduates. RESULTS: A surgeon's region of residence was found to have a statistically significant positive association with that of a surgeon's training structure (P <0.001). A surgeon's professional college or structure of residency has a significantly positive association with desire to complete subspecialty training (P = 0.008). College and structure of residency also are statistically significantly associated with successful completion of subspecialty training (P < 0.001). CONCLUSIONS: These findings provide evidence to support the concept that the segmentation of surgical training structures in Africa, which is the direct result of prior colonization, has affected the distribution of trainees and specialists across the continent and the globe. This maldistribution of African surgical trainees directly impacts patient care, as the surgeon-patient ratios in many African countries are insufficient. These inequities should be acknowledged addressed and rectified to ensure that patients in Africa receive timely and appropriate surgical care.

Rifampicin and protein concentrations in paired spinal versus ventricular cerebrospinal fluid samples of children with tuberculous meningitis.

BACKGROUND: Tuberculous meningitis (TBM) is the most lethal form of TB. To study the disease, drug concentrations in samples obtained from the spinal CSF are usually used to reflect brain concentrations. Emerging data suggest that transport of substances across capillaries in the brain (ventricular CSF) and spinal cord may differ. METHODS: We examined paired, time-linked samples of ventricular CSF (VCSF) and lumbar CSF (LCSF) of 28 patients with TBM and analysed these for rifampicin and total protein concentrations. Clinically indicated samples from procedures to determine the level of CSF block were collected from children being treated for TBM and hydrocephalus. Total protein concentrations were determined using the bicinchoninic acid (BCA) or turbidimetry assay, and rifampicin concentrations were determined using a validated LC coupled with tandem MS method. A paired Wilcoxon signed-rank test was used to determine significance. RESULTS: TBM was confirmed in 19 cases (68%) using TB culture or GeneXpert Mtb/Rifampicin assay. All other cases were classified as probable. The median total protein concentration in LCSF was 6.0 g/L and in VCSF was 1.3 g/L. The median rifampicin concentration in LCSF was 299 ng/mL and 133 ng/mL in VCSF. The median ratio of LCSF/VSCF for protein was 4.23 and 1.57 for rifampicin. CONCLUSIONS: Total protein and rifampicin concentrations differed significantly between the two compartments, both being higher in LCSF than in VCSF samples (P < 0.0001 for total protein and P = 0.0046 for rifampicin). Further studies are required to explore the causative reasons for the observed differences.

Reducing the Gap in Neurosurgical Education in LMICs: A Report of a Non-Profit Educational Program.

INTRODUCTION: Central to neurosurgical care, neurosurgical education is particularly needed in low- and middle-income countries (LMICs), where opportunities for neurosurgical training are limited due to social and economic constraints and an inadequate workforce. The present paper aims (1) to evaluate the validity and usability of a cadaver-free hybrid system in the context of LMICs and (2) to report their learning needs and whether the courses meet those needs via a comprehensive survey. METHODS: From April to November 2021, a non-profit initiative consisting of a series of innovative cadaver-free courses based on virtual and practical training was organized. This project emerged from a collaboration between the Young Neurosurgeons Forum of the World Federation of Neurological Societies (WFNS), the NIHR Global Health Research Group on Neurotrauma, and UpSurgeOn, an Italian hi-tech company specialized in simulation technologies, creator of the UpSurgeOn Box, a hyper-realistic simulator of cranial approaches fused with augmented reality. Over that period, 11 cadaver-free courses were held in LMICs using remote hands-on Box simulators. RESULTS: One hundred sixty-eight participants completed an online survey after course completion of the course. The anatomical accuracy of simulators was overall rated high by the participant. The simulator provided a challenging but manageable learning curve, and 86% of participants found the Box to be very intuitive to use. When asked if the sequence of mental training (app), hybrid training (Augmented Reality), and manual training (the Box) was an effective method of training to fill the gap between theoretical knowledge and practice on a real patient/cadaver, 83% of participants agreed. Overall, the hands-on activities on the simulators have been satisfactory, as well as the integration between physical and digital simulation. CONCLUSIONS: This project demonstrated that a cadaver-free hybrid (virtual/hands-on) training system could potentially participate in accelerating the learning curve of neurosurgical residents, especially in the setting of limited training possibilities such as LMICs, which were only worsened during the COVID-19 pandemic.

The Role of Registries in Neurotrauma Research: Translating Data Into Health Policy That Enhances Patient Care Comment on "Neurotrauma Surveillance in National Registries of Low- and Middle-Income Countries: A Scoping Review and Comparative Analysis of Data Dictionaries".

The paucity of robust neurotrauma data is felt most in regions that experience a higher burden of traumatic brain injury (TBI). The scoping review done by Barthélemy et al provides insight into the current state of national registries in low- and middle-income countries (LMICs) while also exploring the tools required to standardize data collection. In this commentary, we reflect on the barriers to data collection (ie, creation and maintenance of a TBI registry) and explore how registries can aid both scientific output and preventative public awareness campaigns that may pave the way to improved health policy and social change that avert mortality and morbidity from TBI.

Needs, Roles, and Challenges of Young Asian Neurosurgeons.

BACKGROUND: Asia has a marked shortage of neurosurgical care, with approximately 2.5 million critical cases left untreated. The Young Neurosurgeons Forum of the World Federation of Neurosurgical Societies surveyed Asian neurosurgeons to identify research, education, and practice. METHODS: A cross-sectional study using a pilot-tested e-survey was circulated to the Asian neurosurgical community from April to November 2018. Descriptive statistics were used to summarize variables pertaining to demographics and neurosurgical practices. The chi-square test was used to explore the relationship between World Bank income level and variables on neurosurgical practices. RESULTS: A total of 242 responses were analyzed. Respondents were mostly from the low- and middle-income countries (70%). Most represented institutions were teaching hospitals (53%). More than 50% of the hospitals had between 25and 50 neurosurgical beds. Access to an operating microscope (P = 0.038) or image guidance system (P = 0.001) appeared to increase in correlation to a higher World Bank income level. Limited opportunities for conducting research (56%) and hands-on operating opportunities (45%) were leading challenges in daily academic practice. The leading challenges were limited numbers of intensive care unit beds (51%), inadequate or absent insurance coverage (45%), and lack of organized perihospital care (43%). Inadequate insurance coverage decreased with increasing World Bank income levels (P < 0.001). Organized perihospital care (P = 0.001), regular magnetic resonance imaging access (P = 0.032), and equipment necessary for microsurgery (P = 0.007) increased with higher World Bank income levels. CONCLUSIONS: Improving neurosurgical care hinges on regional and international collaboration and national policies to ensure universal access to essential neurosurgical care.

Authorship Disparities in International Neurosurgical Research Collaborations: A Bibliometric Analysis.

BACKGROUND: Research is pivotal to neurosurgical training and practice. The objectives of this study were to quantify neurosurgical research output by authors from low-income countries (LICs), using author affiliation as a proxy, and to understand the patterns of collaboration between LIC authors and their international partners. METHODS: PubMed, CINAHL, and EMBASE were searched for neurosurgical literature published by authors from the 27 World Bank LICs from 2010 to 2020. These articles were screened for relevance. Information about publication type, study design, and author demographics was then extracted from included articles. Scopus was subsequently used to determine the H-indices of the authors. RESULTS: The rate at which LIC authors have been publishing neurosurgical research has increased significantly from 2010 to 2020. Overall, 19 of the 27 LICs were represented. The LICs with the most research output includes Uganda, Ethiopia, and Rwanda. When LIC authors collaborated with authors from middle-or-high-income countries, these LIC researchers were solely listed in a middle authorship position more than 70% of the time. On average, the H-index of LIC authors was 4.9, compared with average H-indices of 8.7 and 16.8 for their MIC and HIC collaborators, respectively. CONCLUSIONS: The positioning of LIC researchers as middle author contributors revealed significant authorship disparities in international neurosurgical research collaborations. The average H-indices of authors from middle-or-high-income countries were more than 3 times greater than those of LIC authors. Quantifying this issue allows neurosurgical organizations to understand the current landscape and to set concrete goals for research capacity building in LICs.

Variation in postoperative outcomes of patients with intracranial tumors: insights from a prospective international cohort study during the COVID-19 pandemic.

BACKGROUND: This study assessed the international variation in surgical neuro-oncology practice and 30-day outcomes of patients who had surgery for an intracranial tumor during the COVID-19 pandemic. METHODS: We prospectively included adults aged ≥18 years who underwent surgery for a malignant or benign intracranial tumor across 55 international hospitals from 26 countries. Each participating hospital recorded cases for 3 consecutive months from the start of the pandemic. We categorized patients' location by World Bank income groups (high [HIC], upper-middle [UMIC], and low- and lower-middle [LLMIC]). Main outcomes were a change from routine management, SARS-CoV-2 infection, and 30-day mortality. We used a Bayesian multilevel logistic regression stratified by hospitals and adjusted for key confounders to estimate the association between income groups and mortality. RESULTS: Among 1016 patients, the number of patients in each income group was 765 (75.3%) in HIC, 142 (14.0%) in UMIC, and 109 (10.7%) in LLMIC. The management of 200 (19.8%) patients changed from usual care, most commonly delayed surgery. Within 30 days after surgery, 14 (1.4%) patients had a COVID-19 diagnosis and 39 (3.8%) patients died. In the multivariable model, LLMIC was associated with increased mortality (odds ratio 2.83, 95% credible interval 1.37-5.74) compared to HIC. CONCLUSIONS: The first wave of the pandemic had a significant impact on surgical decision-making. While the incidence of SARS-CoV-2 infection within 30 days after surgery was low, there was a disparity in mortality between countries and this warrants further examination to identify any modifiable factors.

Population Pharmacokinetic Analysis of Rifampicin in Plasma, Cerebrospinal Fluid, and Brain Extracellular Fluid in South African Children with Tuberculous Meningitis.

Limited knowledge is available on the pharmacokinetics of rifampicin in children with tuberculous meningitis (TBM) and its penetration into brain tissue, which is the site of infection. In this analysis, we characterize the distribution of rifampicin in cerebrospinal fluid (CSF), lumbar (LCSF) and ventricular (VCSF), and brain extracellular fluid (ECF). Children with TBM were included in this pharmacokinetic analysis. Sparse plasma, LCSF, and VCSF samples were collected opportunistically, as clinically indicated. Brain ECF was sampled using microdialysis (MD). Rifampicin was quantified with liquid chromatography with tandem mass spectrometry in all samples, and 25-desacetyl rifampicin in the plasma samples. The data were interpreted with nonlinear mixed-effects modeling, with the CSF and brain ECF modeled as "effect compartments." Data were available from 61 children, with median (min-max) age of 2 (0.3 to 10) years and weight of 11.0 (4.8 to 49.0) kg. A one-compartment model for parent and metabolite with first-order absorption and elimination via saturable hepatic clearance described the data well. Allometric scaling, maturation, and auto-induction of clearance were included. The pseudopartition coefficient between plasma and LCSF/VCSF was ~5%, while the value for ECF was only ~0.5%, possibly reflecting low recovery of rifampicin using MD. The equilibration half-life between plasma and LCSF/VCSF was ~4 h and between plasma and ECF ~2 h. Our study confirms previous reports showing that rifampicin concentrations in the LCSF are lower than in plasma and provides novel knowledge about rifampicin in the VCSF and the brain tissue. Despite MD being semiquantitative because the relative recovery cannot be quantified, our study presents a proof-of-concept that rifampicin reaches the brain tissue and that MD is an attractive technique to study site-of-disease pharmacokinetics in TBM.

Cerebrovascular Pressure Reactivity Has a Strong and Independent Association With Outcome in Children With Severe Traumatic Brain Injury.

OBJECTIVES: To examine cerebrovascular pressure reactivity index (PRx) in a large cohort of children with severe traumatic brain injury (sTBI) in association with physiologic variables and outcome. DESIGN: Retrospective observational cohort study. SETTING: Red Cross War Memorial Children's Hospital in Cape Town, South Africa. PATIENTS: Pediatric (≤ 14 yr old) sTBI patients with intracranial pressure (ICP) monitoring (postresuscitation Glasgow Coma Score [Glasgow Coma Scale (GCS)] of ≤ 8). MEASUREMENTS AND MAIN RESULTS: Data were analyzed from ICM+ files sampled at 100Hz. PRx (a mathematical indicator of pressure reactivity) was calculated as a moving correlation coefficient between ICP and mean arterial pressure (MAP) as previously described. Associations between PRx, age, GCS, ICP, MAP, and cerebral perfusion pressure (CPP) were examined with summary measures and correlation analysis using high-frequency data. Associations between PRx and mortality/outcome were examined with multivariable logistic regression analysis and the prognostic ability of PRx with receiver operating characteristic (ROCs) curves. The dataset included over 1.7 million minutes (28,634 hr) of MAP and ICP data in 196 children. The series mortality was 10.7% (21/196), and unfavorable outcome 29.6% (58/196). PRx had a moderate positive correlation with ICP ( r = 0.44; p < 0.001), a moderate negative correlation with CPP ( r = -0.43; p < 0.001), and a weak negative correlation with MAP ( r = -0.21; p = 0.004). PRx was consistently higher in patients with poor outcome and had a strong, independent association with mortality (ROC area under the curve = 0.91). A PRx threshold of 0.25 showed the best predictive ability for mortality. CONCLUSIONS: This is the largest cohort of children with PRx analysis of cerebrovascular reactivity to date. PRx had a strong association with outcome that was independent of ICP, CPP, GCS, and age. The data suggest that impaired autoregulation is an independent factor associated with poor outcome and may be useful in directing clinical care.

Biochemical profile of paediatric adamantinomatous craniopharyngiomas: A prospective cohort study.

Introduction: Craniopharyngioma is a rare brain tumour. Despite being histologically benign, it behaves aggressively and is often difficult to manage. Descriptive epidemiological data on the tumour is lacking in sub-Saharan Africa, and there is none for Zimbabwe. The tumour usually has a cystic component that has been raising interest in the past decade. Few studies have looked at the biochemical composition thereof. This study aims to give a landscape view of craniopharyngiomas (CPs) in Zimbabwe and then profile the biochemical properties of the cystic component of paediatric adamantinomatous craniopharyngioma. Methodology: A prospective cohort study was done in Zimbabwe over a 2-year period to study the epidemiological distribution of craniopharyngioma and examine the biochemical composition of adamantinomatous craniopharyngioma cystic fluid in the paediatric population. Fifteen patients were recruited who had craniopharyngiomas, and of those, nine paediatric adamantinomatous craniopharyngiomas had fluid analysed for biochemical components. SPSS statistical package was used to analyse the data. Descriptive statistics were used for epidemiological data. Results: The incidence of CP was calculated to be 0.53 per million person-years. Incidence among the paediatric population 0-14 years was 1.2 per 100,000 person-years. Several biological components were found to be elevated significantly compared to serum and cerebral spinal fluid (CSF). These are sodium, potassium, urea, alkaline phosphatase, phosphate, magnesium, albumin, gamma-glutamyl transferase, calcium, low-density lipids, and glucose. Conclusion: The incidence of CP in Zimbabwe is similar to the rest of the world. Some biochemical components have been noted to be markedly elevated in the cystic fluid and were mirroring serum rather than CSF in concentration.

Observational Studies in Neurosurgery: Structure, Functioning, and Uses.

INTRODUCTION: Although randomized interventional studies are the gold standard of clinical study designs, they are not always feasible or necessary. In such cases, observational studies can bring insights into critical questions while minimizing harm and cost. There are numerous observational study designs, each with strengths and demerits. Unfortunately, it is not uncommon for observational study designs to be poorly designed or reported. In this article, the authors discuss similarities and differences between observational study designs, their application, and tenets of good use and proper reporting focusing on neurosurgery. METHODS: The authors illustrated neurosurgical case scenarios to describe case reports, case series, and cohort, cross-sectional, and case-control studies. The study design definitions and applications are taken from seminal research methodology readings and updated observational study reporting guidelines. RESULTS: The authors have given a succinct account of the structure, functioning, and uses of common observational study designs in Neurosurgery. Specifically, they discussed the concepts of study direction, temporal sequence, advantages, and disadvantages. Also, they highlighted the differences between case reports and case series; case series and descriptive cohort studies; and cohort and case-control studies. Also, they discussed their impacts on internal validity, external validity, and relevance. CONCLUSION: This paper disambiguates widely held misconceptions on the different observational study designs. In addition, it uses case-based scenarios to facilitate comprehension and relevance to the academic neurosurgery audience.

Prevalence of spine surgery navigation techniques and availability in Africa: A cross-sectional study.

BACKGROUND: Africa has a large burden of spine pathology but has limited and insufficient infrastructure to manage these spine disorders. Therefore, we conducted this e-survey to assess the prevalence and identify the determinants of the availability of spine surgery navigation techniques in Africa. MATERIALS AND METHODS: A two-part questionnaire was disseminated amongst African neurological and orthopedic surgery consultants and trainees from January 24 to February 23, 2021. The Chi-Square, Fisher Exact, and Kruskal-Wallis tests were used to evaluate bivariable relationships, and a p-value <0.05 was considered statistically significant. RESULTS: We had 113 respondents from all regions of Africa. Most (86.7 %) participants who practiced or trained in public centers and centers had an annual median spine case surgery volume of 200 (IQR = 190) interventions. Fluoroscopy was the most prevalent spine surgery navigation technique (96.5 %), followed by freehand (55.8 %), stereotactic without intraoperative CT scan (31.9 %), robotic with intraoperative CT scan (29.2 %), stereotactic with intraoperative CT scan (8.8 %), and robotic without intraoperative CT scan (6.2 %). Cost of equipment (94.7 %), lack of trained staff to service (63.7 %), or run the equipment (60.2 %) were the most common barriers to the availability of spine instrumentation navigation. In addition, there were significant regional differences in access to trained staff to run and service the equipment (P = 0.001). CONCLUSION: There is a need to increase access to more advanced navigation techniques, and we identified the determinants of availability.