A brief retrospective of the history of neurosurgery in Croatia.

The beginnings of neurosurgery in Croatia date to the end of the 19th century when Teodor Wickerhauser performed the first craniotomy in the country in 1886. Exactly 60 years later, in 1946, Danko Riessner founded a separate neurosurgical ward in Zagreb and is therefore considered the founder of Croatian neurosurgery. His main scientific contribution was a paper on the shifting of brain masses, published in 1939. The Department of Neurosurgery at the University of Zagreb was founded in 1974 as one of the first institutions of its kind in Southeast Europe. Finally, the Croatian Neurosurgical Society was founded in 1992 to promote the neurosurgical profession and science at the national level. This historical vignette aimed to provide a brief chronology of the most important events and notable people in the history of Croatian neurosurgery, as well as to commemorate its founders and highlight its development from the beginning to its current state of proficiency and expertise.

Cranioorbital Pretemporal Skull Base Approach with Anterior Clinoidectomy for Removal of Large Left Clinoid Meningioma: "Unwrapping" Encircled Internal Carotid Artery and Decompressing Optic Nerve: 2-Dimensional Operative Video.

Clinoidal meningiomas are meningiomas arising from or in the vicinity of the anterior clinoid process.1 Despite advanced microsurgical techniques, clinoidal meningiomas remain challenging.2 Extradural anterior clinoidectomy with optical unroofing remains an important tool in skull base surgery, which provides a safe operative corridor, facilitating greater extent of resection and enhancing overall outcome, particularly visual function.2-13 A 66-year-old woman presented with history of visual disturbances. Magnetic resonance imaging revealed a dural-based tumor consistent with a large left clinoidal meningioma, with tumor wrapping (encircling) around the left trunk and internal carotid artery (ICA) bifurcation, elevating the left middle cerebral artery M1 segment, and invading the left optic canal. Left cranio-orbital craniotomy with pretemporal exposure was used (Video 1).1,9 A high-speed diamond drill with irrigation completed the extradural anterior clinoidectomy and optical canal unroofing. Use of a 1-mm Kerrison rongeur should be done with utmost care. The tumor was unwrapped via meticulous piecemeal removal. Final dissection and ICA unwrapping was done when the tumor was debulked enough that dissecting it off the artery was safe and under less tension. Due to its obscurity, final decompression of the left optic nerve with incision and opening of the falciform ligament was performed at the end of the procedure.10 Postoperative neuro-ophthalmologic examination showed a grossly unchanged left visual field with some visual acuity improvement. Resection of tumor encircling the ICA has been described previously;14 however, to the best of our knowledge, this is the first video describing removal of a tumor surrounding the ICA (perfomed by senior author K.I.A.), essentially "unwrapping" the left ICA trunk and its bifurcation. The patient consented to publication.

Effect of Body Mass Index on Chiari Malformation 1 Tonsil Ectopia Length in Adults.

OBJECTIVE: Diagnosis of Chiari I malformation (CM-1) is based on measurements of the inferior extension of the cerebellar tonsils into the foramen magnum on cranial or cervical spine magnetic resonance imaging. Imaging may be obtained before the patient is referred to the neurosurgical specialist. The length of time raises questions about the possibility that body mass index (BMI) fluctuations could affect the measurement of ectopia length. However, previous literature on BMI and CM-1 has reported conflicting findings on BMI. METHODS: We conducted a retrospective chart review of 161 patients who were referred to a single neurosurgeon for CM-1 consultation. Patients with multiple recorded BMI values (n = 71) were compared to see if BMI changes correlated with changes in ectopia length. In addition, we compared and tested 154 recorded ectopia lengths from the patients (1 per patient) and patient BMI values with Pearson correlation and Welch t tests to determine if BMI changes either influenced or were associated with ectopia changes. RESULTS: For the 71 patients with multiple BMI values, change in ectopia length ranged from -4.6-9.8 mm but was not statistically significant (r = 0.019; P = 0.88). For the 154 measured ectopia lengths, changes in BMI did not correlate with ectopia length (P > 0.05). Likewise, differences in ectopia length between patients in normal, overweight, and obese categories were not statistically significant (|tstat| < |tcrit|, P > 0.05). CONCLUSIONS: In individual patients, we found that BMI and changes in BMI were not accompanied by changes in tonsil ectopia length.

Bibliometric Analysis of 6 Major European Neurosurgical Publications from 2011-2020 (part 3): a Comparative Metrics Review.

Background: We previously conducted bibliometric analysis of 6 North American neurosurgical journals. Objective: To perform a bibliometric analysis of 6 European neurosurgical journals to build on our previous studies. Methods: We searched Web of Science for articles published in Acta Neurochirurgica, British Journal of Neurosurgery, Child's Nervous System, Journal of Neurological Surgery Part A: Central European Neurosurgery, Journal of Neurosurgical Sciences, and Neurosurgical Review between 2011 and 2020. We analyzed bibliometric parameters related to total annual document distribution, author metrics, journal metrics, country and continental distribution, institution, keywords, and journal impact. Results: European countries provided the greatest contributions. Acta Neurochirurgica followed by Child's Nervous System published the greatest number of articles and had the highest h-index and number of citations. From 2018 to 2020, total documents increased 79.6%, original articles increased 86.5%, review articles increased 103.6%, citations increased 79.6%, number of publishing authors increased 72.1%, number of authors in multi-author documents increased 72.4%, and author's keywords and keywords plus increased 72.4% and 27.0%, respectively. The collaboration index decreased 5.3% from 4.49 to 4.25. Annual published documents and citations were lower for European journals versus North American journals. Conclusion: Several parameters of the European journals increased by 2020. One interesting finding is that growth for the 6 journals dramatically increased in the 2 years prior to the COVID-19 pandemic. While neurosurgeon free time during lockdowns may account for much of the increase in 2020, the trend began before this. Our analysis did not identify a cause for the pre-COVID increases.

An integrative survival analysis and a systematic review of the cerebellopontine angle glioblastomas.

Glioblastomas presenting topographically at the cerebellopontine angle (CPA) are exceedingly rare. Given the specific anatomical considerations and their rarity, overall survival (OS) and management are not discussed in detail. The authors performed an integrative survival analysis of CPA glioblastomas. A literature search of PubMed, Scopus, and Web of Science databases was performed per PRISMA guidelines. Patient data including demographics, clinical features, neuroimaging, management, follow-up, and OS were extracted. The mean age was 39 ± 26.2 years. The mean OS was 8.9 months. Kaplan-Meier log-rank test and univariate Cox proportional-hazards model identified hydrocephalus (log-rank, p = 0.034; HR 0.34; 95% CI 0.12-0.94; p = 0.038), chemotherapy (log-rank, p < 0.005; HR 5.66; 95% CI 1.53-20.88; p = 0.009), and radiotherapy (log-rank, p < 0.0001; HR 12.01; 95% CI 3.44-41.89; p < 0.001) as factors influencing OS. Hydrocephalus (HR 3.57; 95% CI 1.07-11.1; p = 0.038) and no adjuvant radiotherapy (HR 0.12; 95% CI 0.02-0.59; p < 0.01) remained prognostic on multivariable analysis with fourfold and twofold higher risk for the time-related onset of death, respectively. This should be considered when assessing the risk-to-benefit ratio for patients undergoing surgery for CPA glioblastoma.

Cranial Versus Cervical Spine Magnetic Resonance Imaging in Adult Chiari Malformation Type I Diagnostics: Is There a Difference in Tonsil Ectopia Length?

BACKGROUND: Chiari malformation type 1 (CM-1) diagnosis is based on measurement of the cerebellar tonsils on cranial or cervical spine magnetic resonance imaging (MRI). However, imaging parameters of cranial and cervical spine MRI could differ because spine MRI has greater resolution. METHODS: We conducted a retrospective chart review of 161 patients of a single neurosurgeon for adult CM-I consultation between February 2006 and March 2019. Patients were selected based on receiving both cranial and cervical spine MRI within a month of each other to determine tonsillar ectopia length for CM-1. Ectopias were measured to determine if differences in values were statistically significant. RESULTS: From the 161 total patients, 81 had cranial and cervical spine MRI for a total of 162 tonsil ectopia measurements (81 cranial and 81 spinal). Average ectopia length on a cranial MRI was 9.1 mm (±5.2 mm); average ectopia length on a spinal MRI was 8.9 mm (±5.3 mm). Average cranial and spinal MRI values were found to be <1 standard deviation apart. Two-tailed, nonequal variances t test determined that differences between the cranial and spinal ectopia measurements were insignificant (P = 0.2403). CONCLUSIONS: This study confirmed that the added resolution offered by spine MRI did not make better or more refined measurements over cranial MRI that could lead to measurement differences, which can instead be attributed to chance. Cranial and cervical spine MRI can be used to determine the degree of the tonsil ectopia.

Supratentorial Hemangioblastoma in Adults: A Systematic Review and Comparison of Infratentorial and Spinal Cord Locations.

BACKGROUND: Supratentorial hemangioblastomas are benign and highly vascularized neoplasms that appear most often in the spine and posterior cranial fossa. They can also be located in the supratentorial compartment of the brain. We conducted a systematic review of the literature to better understand the clinical insights of supratentorial hemangioblastoma in adults. METHODS: Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, the authors reviewed the English-language literature in the PubMed/MEDLINE database on supratentorial hemangioblastoma in adults, published in the past 40 years. We analyzed the differences between sporadic hemangioblastomas and hemangioblastomas associated with von Hippel-Lindau disease. In addition, we compared the characteristics of supratentorial hemangioblastomas with infratentorial and spinal cord locations. RESULTS: We reviewed 92 articles, describing 157 supratentorial hemangioblastomas in a total cohort of 148 adult patients. Most articles reporting supratentorial hemangioblastomas were published in the United States. Supratentorial hemangioblastomas occur more frequently in women than men. The median age at the time of diagnosis was 44.48 years. The sellar/parasellar region was the most commonly tumor location, while the most common morphological type was the solid type. Almost 80% of hemangioblastomas were completely resected; the outcome was favorable in more than 3 fourth of patients. CONCLUSIONS: Given their rarity, the literature on supratentorial hemangioblastomas is limited and based mostly on case reports. Complete surgical resection is the first choice of treatment and is associated with a good treatment outcome.

Cisternal, Falciform, and Optic Canal Decompression Influencing Optic Nerve Biomechanics: A Microsurgical Anatomic Study.

BACKGROUND: Questions remain regarding optic nerve (ON) physiology, mechanical compliance, and microvasculature, particularly surgical outcomes and atypical visual field defects associated with sellar/parasellar pathology (eg, tumors and aneurysms). OBJECTIVE: To study the microsurgical/histological anatomy of each ON segment and corresponding microvasculature, calculate area of optic-carotid space at each decompression stage, and measure ON tension before/after compression. METHODS: Five cadaveric heads (10 sides) underwent sequential dissection: (1) intradural (arachnoidal) ON dissection; (2) falciform ligament opening; (3) anterior clinoidectomy, optic canal decompression, and ON sheath release. At each step, we pulled the nerve superiorly/laterally with a force meter and measured maximal mobility/mechanical tension in each position. RESULTS: Cisternal ON microvasculature was more superficial and less dense vs the orbital segment. ON tension was significantly lower with higher mobility when manipulated superiorly vs lateromedially. Optic-carotid space significantly increased in size at each decompression stage and with ON mobilization both superiorly and laterally, but the increase was statistically significant in favor of upward mobilization. At decompression step, upward pull provided more space with less tension vs side pull. For upward pull, each step of decompression provided added space as did side pull. CONCLUSION: Opening the optic canal, falciform ligament, and arachnoid membrane decompresses the ON for safer manipulation and provided a wider optic-carotid surgical corridor to access sellar/parasellar pathology. When tailoring decompression, the ON should be manipulated superiorly rather than lateromedially, which may guide surgical technique, help prevent intraoperative visual deterioration, facilitate postoperative visual improvement, and help understand preoperative visual field deficits based on mechanical factors.

Adult Chiari Malformation Type I: Surgical Anatomy, Microsurgical Technique, and Patient Outcomes.

In this study, the authors summarize the current knowledge on epidemiology, demographics, risk factors, and prognostic factors that influence outcomes in patients with adult Chiari malformation type I (CM-I) who underwent posterior fossa decompression surgery with duraplasty. Furthermore, they describe the contribution of their research group to the field of adult CM-I treatment, including association of increased body mass index with severity of CM-I and syringomyelia, relevant surgical anatomy, and surgical technique of 270° microsurgical decompression of foramen magnum. The authors also report on common complications in the literature and describe techniques for prevention of complications.

Spontaneous Bleeding in Vestibular Schwannoma in Patients on Oral Anticoagulant Therapy: Report of Two Cases and Review of Literature.

OBJECTIVE: Anticoagulant therapy is a risk factor for repeated intratumoral hemorrhage and acute enlargement of a vestibular schwannoma (VS) with neurological deficits. Therefore, we describe two cases of patients on oral anticoagulant therapy with intratumoral hemorrhage in which anticoagulant therapy prior to surgical resection was discontinued. We also discuss other similar cases from the literature since this is a rare event. CASE REPORTS: We described the two cases of intratumoral hemorrhage in acoustic neurinoma and conducted a literature review of similar cases of patients with intratumoral hemorrhage in acoustic neurinoma who were also on oral anticoagulants. Both patients presented with CN-VII palsy prior to surgery; both also fully re-covered after surgery except for hearing loss on the tumor side. Our literature review found 50 cases of VS (reported as vestibular schwannomas in the literature) with intratumoral hemorrhage. From this total, 11 patients used oral anticoagulant therapy with reported poor outcomes and high mortality; 9 of these 11 cases were reported in the past 20 years. The incidence is expected to rise due to increased use of anticoagulant therapy due to onset of atrial fibrillation, atherosclerosis, and thromboembolism from longer human lifespan. CONCLUSION: Anticoagulant therapy represents a risk factor for intratumoral hemorrhage and acute enlargement of VS tumor mass with neurological deficits.

Bibliometric Analysis of Major Neurosurgical Publications 2011-2020, Part 2: Journal, Author, Yearly Publication Trends, and Citation Related Metrics.

Background: Scientometrics, a subfield of bibliometrics, examines scientific publications by using bibliometric methods. The aim of a scientometric study is to study the various citation-based metrics of scientific articles, such as parameters pertaining to authors (including institutions and country of origin), articles, journals, and other citation related metrics. Objective: In this second part of our scientometric analysis of the 6 major neurosurgical journals from 2011-2020, we study journal and author trends, yearly publication trends, and citation related metrics in Neurosurgery, Journal of Neurosurgery, Journal of Neurosurgery: Spine, Journal of Neurosurgery: Pediatrics, Operative Neurosurgery, and World Neurosurgery. Methods: We analyzed parameters, including article and journal metrics (total articles published per journal per year, breakdown of the Bradford's law distribution of journals, and Lotka's law, journal impact factors), author metrics (country of origin, collaborations), citation totals, and keyword counts. Results and Discussion: The highest number of published articles from all journals occurred in 2011, the lowest in 2016. World Neurosurgery published the most. The author collaboration index has declined since 2016 with a notable drop in 2020 when the COVID-19 pandemic began. Impact factors remained stable, except for Operative Neurosurgery, which experienced a steep decline in 2020, and World Neurosurgery, which experienced a mild decline in 2020. Canadian authors were the most likely to participate in multi-country collaborations. Conclusion: The most articles were published in Journal of Neurosurgery, followed by Neurosurgery, Spine, and World Neurosurgery.

Lessons learned during covid-19 pandemic, a worldwide survey: evolution of global neurosurgical practice.

BACKGROUND: During the COVID-19 pandemic, a multitude of surveys have analyzed the impact virus spreading on the everyday medical practice, including neurosurgery. However, none have examined the perceptions of neurosurgeons towards the pandemic, their life changes, and the strategies they implemented to be able to deal with their patients in such a difficult time. METHODS: From April 2021 to May 2021 a modified Delphi method was used to construct, pilot, and refine the questionnaire focused on the evolution of global neurosurgical practice during the pandemic. This survey was distributed among 1000 neurosurgeons; the responses were then collected and critically analyzed. RESULTS: Outpatient department practices changed with a rapid rise in teleservices. 63.9% of respondents reported that they have changed their OT practices to emergency cases with occasional elective cases. 40.0% of respondents and 47.9% of their family members reported to have suffered from COVID-19. 56.2% of the respondents reported having felt depressed in the last 1 year. 40.9% of respondents reported having faced financial difficulties. 80.6% of the respondents found online webinars to be a good source of learning. 47.8% of respondents tried to improve their neurosurgical knowledge while 31.6% spent the extra time in research activities. CONLCUSIONS: Progressive increase in operative waiting lists, preferential use of telemedicine, reduction in tendency to complete stoppage of physical clinic services and drop in the use of PPE kits were evident. Respondents' age had an impact on how the clinical services and operative practices have evolved. Financial concerns overshadow mental health.

Novel Clinical Insights into Spinal Hemangioblastoma in Adults: A Systematic Review.

BACKGROUND: Hemangioblastomas (HBs) are well-vascularized, benign central nervous system tumors and the third most common primary spinal cord tumor after astrocytoma/ependymoma, occurring sporadically or as a part of autosomal dominant von Hippel-Lindau disease, in which tumors are often multiple and prone to relapse. Spinal HBs are commonly located in the cervical cord and associated with a syrinx formation. Owing to location and growth trends, they may cause significant neurological deficit, impairing quality of life. We conducted a systematic review to understand better clinical insights into spinal HB in adults and compare spinal HB versus posterior cranial fossa HB. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines for conducting systematic reviews, we reviewed the English-language literature on adult spinal HB in the MEDLINE/PubMed database over the last 40 years. RESULTS: We reviewed 237 articles on adult spinal HB and analyzed national and continental distribution, clinical symptoms, tumor location and presence of syringomyelia, treatment strategies and postoperative complications, histology and immunochemistry, and treatment outcomes. We compared individual characteristics in sporadic and von Hippel-Lindau disease spinal HBs. Finally, we compared features of posterior cranial fossa and spinal HBs. CONCLUSIONS: Spinal cord HBs most commonly have a dorsal intramedullary location. Total surgical tumor resection is the first treatment option; preoperative embolization may be performed to reduce intraoperative bleeding and surgical time. HBs located in the spine have decreased mortality and rate of infection, but increased rates of cardiopulmonary complications compared with HBs in the posterior cranial fossa.

First documented clinical account of brachial plexus palsy from the 12th century.

OBJECTIVE: Although literary depiction of brachial plexus injury can be traced to Homer's Iliad, there is a scientific consensus that the first clinical description of brachial plexus palsy was not documented until the British physician Smellie reported it in the 18th century. However, the authors' recent review of the Syriac Book of Medicines (12th century) has uncovered a much earlier clinical documentation. METHODS: For this historical vignette, the authors reviewed the historical and anatomical literature regarding earlier descriptions of brachial plexus anatomy and pathology, including a thorough analysis of the Syriac Book of Medicines (attributed to an unknown Syriac physician in the Middle Ages) and Galen's On Anatomical Procedures and On the Usefulness of the Parts of the Body. RESULTS: Building on the galenic tradition with reference to independent dissections, the Syriac physician discussed nervous system anatomy and the clinical localization of neurological injuries. He described a patient who, after initial pulmonary symptoms, developed upper-extremity weakness more pronounced in the proximal muscles. His anatomical correlation placed the injury "where the nerves issue from the first and second muscles between the ribs" (scalene muscles), are "mixed," and "spread through many parts." The patient's presentation and recovery raise the possibility of Parsonage-Turner syndrome. The anatomical description of the brachial plexus is in line with Galen's earlier account and step-by-step surgical exposure, which the authors reviewed. They also examined Ibn Ilyas' drawing of the brachial plexus, which is believed to be a copy of the earliest artistic representation of the plexus. CONCLUSIONS: Whereas the Middle Ages were seen as a period of scientific stagnation from a Western perspective, Galen's teachings continued to thrive and develop in the East. Syriac physicians were professional translators, clinicians, and anatomists. There is evidence that brachial plexus palsy was documented in the Syriac Book of Medicines 6 centuries before Smellie.

Bibliometric Analysis of Publications From 2011-2020 in 6 Major Neurosurgical Journals (Part 1): Geographic, Demographic, and Article Type Trends.

INTRODUCTION: Scientometrics is a subfield of bibliometrics that statistically analyzes publications trends. The aim of this initial study was to investigate trends in the 6 major neurosurgical journals from the last 10 years. METHODS: We searched Web of Science and Scopus for articles published in Neurosurgery, Journal of Neurosurgery, Journal of Neurosurgery: Spine, Journal of Neurosurgery: Pediatrics, Operative Neurosurgery, and World Neurosurgery from January 1, 2011, to December 31, 2020. Statistically analyzed parameters included national and continental distribution of articles, population density, density of neurosurgeons per 100,000 inhabitants, national per capita GDP, and national literacy rates. Bibliometric parameters assessed included total number of articles, H-indices, absolute/average number of citations per article, and article types. RESULTS: A total of 39,239 articles were published in the 6 journals. Journal of Neurosurgery and Neurosurgery had the strongest source impact. The most productive year was 2019 with 6811 published articles. Corresponding authors from the USA, China, Japan, Western Europe, and Turkey were the most productive. Articles published by authors from the USA received the majority of citations. Publication numbers increased in proportion with increases in country population, literacy rate, per capita GDP, and neurosurgeon density. The highest number of articles were published in 2016, and the fewest were published in 2020. CONCLUSIONS: Geographic trends in the diversity of neurosurgical publications sustained its steady increase in most developed counties. Simultaneously, the publication gap between developed and developing countries has remained stagnant.