OBJECTIVE:The cerebral and spinal venous systems have similar functions but unique anatomical and physiological properties. CSF occupies space in the cranial and spinal vaults, is continuously produced, and has many roles, including maintaining a favorable environment for CNS structures. The influence of the cerebrospinal venous system on CSF dynamics has been theorized since the 1940s. Newer studies suggest venous outflow pattern alterations in response to changes in body position. However, the relationship of postural cerebrospinal venous outflow shifts with and their influence on CSF homeostasis is not well understood. METHODS:The authors searched the published literature related to the anatomy and function of vertebral venous plexus (VVP), CSF, and positional cerebral venous flow characteristics. A comprehensive collection of literature was compiled and reviewed, and the relationship between cerebrospinal and venous system changes and alterations in body positions, with an emphasis on the craniocervical system, is discussed. RESULTS:The VVP is a network of valveless veins extending from the sacrum to the cranium that are interconnected with the cranial dural sinuses. The internal VVP occupies space within the extradural spinal canal and functions to return spinal venous blood to the heart, but it has additional properties, including the capability of bidirectional venous flow, an intraspinal dilatory capacity, and a role in cerebral venous outflow. When one rises to the upright position, CSF shifts toward the spinal canal and force vectors change, leading to reduced intracranial CSF pressure; simultaneously, cerebral venous outflow shifts from the jugular vein to the VVP outflow pathway. The venous outflow shift mechanism and its purpose are poorly understood. The authors review the known physiology of the system, identify gaps in knowledge to direct future research, and propose an interpretation of these data, concluding that position-dependent CSF and cerebrospinal venous shifts are part of a complementary positional craniospinal pressure regulation system that must be kept in balance for optimal CNS function. CONCLUSIONS:Current knowledge of the cerebrospinal venous anatomy, dynamic flow characteristics in response to gravity, and the venous system's influence on CSF suggests that the VVP plays a role in influencing CSF pressure, and the authors hypothesize that it plays a role in supporting intracranial pressure in the upright body posture. Further research is needed to better characterize the functional relationship of the VVP to CSF dynamics as well as identify potentially related disease states.

OBJECTIVE:Genetic alterations are increasingly recognized as etiologic factors linked to the pathogenesis and development of cerebrovascular anomalies. Their identification allows for advanced screening and targeted therapeutic approaches. The authors aimed to describe the role of a collaborative approach to care and genetic testing in pediatric patients with neurovascular anomalies, with the objectives of identifying what genetic testing recommendations were made, the yield of genetic testing, and the implications for familial screening and management at present and in the future.METHODS:The authors performed a descriptive retrospective cohort study examining pediatric patients genetically screened through the Pediatric Neurovascular Program of a single treatment center. Patients 18 years of age and younger with neurovascular anomalies, diagnosed radiographically or histopathologically, were evaluated for germline genetic testing. Patient demographic data and germline genetic testing and recommendation, clinical, treatment, and outcome data were collected and analyzed.RESULTS:Sixty patients were included; 29 (47.5%) were female. The mean age at consultation was 11.0 ± 4.9 years. Diagnoses included cerebral arteriovenous malformations (AVMs) (n = 23), cerebral cavernous malformations (n = 19), non-neurofibromatosis/non-sickle cell moyamoya (n = 8), diffuse cerebral proliferative angiopathy, and megalencephaly-capillary malformation. Of the 56 patients recommended to have genetic testing, 40 completed it. Genetic alterations were found in 13 (23%) patients. Four patients with AVMs had RASA1, GDF2, and ACVRL1 mutations. Four patients with cavernous malformations had Krit1 mutations. One with moyamoya disease had an RNF213 mutation. Three patients with megalencephaly-capillary malformation had PIK3CA mutations, and 1 patient with a cavernous sinus lesion had an MED12 mutation. The majority of AVM patients were treated surgically. Patients with diffuse cerebral proliferative angiopathy were treated medically with sirolimus. At-risk relatives of 3 patients positive for genetic anomalies had also been tested.CONCLUSIONS:This study demonstrates a role for exploring genetic alterations in the identification and treatment of pediatric neurovascular disease pathogenesis. Germline genetic mutations were found in almost one-quarter of the patients screened in this study, results that helped to identify medically targeted treatment modalities for some pediatric neurovascular patients. Insight into the genetic etiology of vascular anomalies may provide broader clinical implications for risk assessment, family screening, follow-up surveillance, and medical management.

A middle-aged patient presented with right-sided chemosis, exophthalmos, and progressive visual loss. Digital subtraction angiography revealed a type D carotid-cavernous fistula (CCF). Transarterial embolization through the internal maxillary artery was unsuccessful, and there was no venous access to the CCF. A robotic-guided direct transtemporal embolization of the CCF with Onyx was performed, resulting in successful fistula obliteration and symptom resolution. This is the first reported case of a robotic-guided direct transcranial CCF embolization. We include a technical video that demonstrates this procedure (Supplemental File 1)

Paracavernous dural arteriovenous fistulas (pdAVFs) are extremely rare and can mimic carotid cavernous fistulas (CCFs) in both clinical presentation and imaging characteristics. Access to the venous pouch often presents the greatest challenge in the treatment of pdAVFs. Here we present a novel access technique utilizing an endoscopic endonasal transsphenoidal approach, where we directly puncture the venous pouch under both stereotactic guidance and endoscopic visualization, thereby completely embolizing a pdAVF with no alternate access (video 1). neurintsurg;15/10/1055/V1F1V1Video 1Technical video demonstrates the complete embolization of a pdAVF using an endoscopic endonasal transsphenoidal approach.

Arachnoid cysts of the fourth ventricle are rarely reported. Management options include CSF diversion, cyst fenestration, or cyst excision. Fenestration can be done via open microsurgical technique or endoscopically with or without simultaneous third ventriculostomy; and both rigid and flexible endoscopy have been used successfully. However, application of this treatment modality in pediatric patients is not well described. Therefore, to their knowledge, the authors report the first successful treatment of a fourth ventricular arachnoid cyst with a single frontal burr hole entry point for third ventriculostomy and fourth ventricular arachnoid cyst fenestration performed using flexible neuroendoscopy. The patient was a 13-month-old boy presenting with progressive macrocephaly. The authors review their technique, discuss special considerations when using this approach, and include an annotated intraoperative video for demonstration to help instruct and guide management. The authors demonstrate with an example that a single frontal burr hole entry point for flexible endoscopic third ventriculostomy and navigation through a dilated cerebral aqueduct for fourth ventricular arachnoid cyst fenestration is a viable treatment for symptomatic fourth ventricular arachnoid cysts in children.

The Woven EndoBridge (WEB) device was approved by the U.S. FDA for its excellent angiographic occlusion of intracranial aneurysms and high safety profile, based on the landmark WEB-IT (WEB Intrasaccular Therapy) trial. There remains, however, a few cases of aneurysm recurrence that necessitate retreatment after the initial WEB procedure. In this technical video, the authors present the case of a middle-aged patient who showed significant basilar apex aneurysm recurrence and growth along with device compaction that required retreatment. Various aspects of treating aneurysms with a prior WEB device, including procedural technique, are discussed. The video can be found here: https://stream.cadmore.media/r10.3171/2022.7.FOCVID21152.

The coronavirus 2019 (COVID-19) pandemic has had drastic effects on the volume of neurosurgical procedures. This decrease was seen worldwide with institutions reporting a drop in surgical volume of up to 54.7%. In the United States, Emory University reported an 80% decrease in case of volume during the lockdown period from March 16 to April 15, 2020. In France, 32 centers reported a 21% decrease in mechanical thrombectomy volume during the lockdown period compared to 2019. However, there have been few reports of endovascular volume beyond the initial lockdown period of the pandemic. The present study reports neuro-endovascular volume in the US during various phases of the COVID-19 pandemic with a focus on aneurysm treatment. We also discuss how normalization of volume may be achieved.

C © Congress of Neurological Surgeons 2021. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com T he safety, efficacy, and feasibility of the transradial artery (TRA) approach for neurointerventional procedures have largely been established in recent years.1,2 While the traditional transfemoral artery approach (TFA) is still widely used in neurointerventional surgery, a growing number of institutions are spearheading an effort to adopt a radialfirst approach to neurointerventional procedures, helping usher in a field-wide paradigm shift that is currently underway. This trend is supported by literature showing that the TRA approach allows for a host of advantages, including improved hemostasis, fewer access site complications, decreased postprocedure discomfort, and lower hospital cost.3,4 A great majority of such studies, however, is limited to studying its efficacy in diagnostic procedures as opposed to neurointerventional treatments. In the recent Neurosurgery article “PropensityAdjusted Comparative Analysis of Radial Versus Femoral Access for Neurointerventional Treatments,” the authors sought to fill this gap. The authors5 retrospectively reviewed a total of 579 neurointerventional treatments performed between October 2018 and December 2019 at a single institution. Of these treatments, 163 procedures were attempted with a TRA approach while the remaining 416 were attempted with a TFA approach. Patients were thus grouped into cohorts on the basis of treatment access, and outcomes such as complications, fluoroscopy times, and total contrast administered were collected. Five cases of complications were observed for the TRA procedures compared to the 43 cases that were observed for the TFA procedures, resulting in TFA having a significantly higher complication rate (P = .008). Even upon excluding patients who underwent thrombectomy and performing a propensity adjustment (including age, sex, pathology, procedure, sheath size, and catheter size), TRA was associated with decreased odds of a complication yet no significant differences in the amount contrast administered or the duration of fluoroscopy compared to TFA. These findings are compelling when compared to the outcomes for similar studies on diagnostic procedures. The authors identified in the study by Khanna et al6 that there was an increase in patient satisfaction associated with TRA access for the 98 patients who underwent both TRA and TFA approaches, although only diagnostic procedures were compared. A recent multicenter study3 also found a similar low rate of complications associated with TRA access, although the study was single-armed and thus no comparison with TFA procedures were performed. The authors of the current study note that during their 9-mo transition to a radial-first practice, their initial analysis indicated that TRA procedures were associated with a longer fluoroscopy time than TFA approaches. Beyond the first 9 mo, however, the fluoroscopy times were equivalent. While the decreased complication rates and equivalent fluoroscopy time are impressive, we believe that patient satisfaction should also be an important consideration in the widespread adoption of the TRA approach in neurointerventional procedures. A single-center noninferiority comparative effectiveness study by Stone et al7 reports that patient satisfaction significantly favored the radial approach over femoral concerning a number of measures including access site pain after sheath insertion and removal, back pain before discharge, embarrassment, anxiety, and overall discomfort. Patients in their TRA approach group also reported a statistically higher preference for radial access should they need to undergo another angiogram. Results from several other institutions echo their findings, with evidence showing that TRA is associated with reductions in not only access site complications, morbidity, mortality, but also length of hospital stay and costs as well as an overall increase in patient satisfaction compared to TFA approach.8,9

Background Academic physicians aim to provide clinical and surgical care to their patients while actively contributing to a growing body of scientific literature. The coronavirus disease 2019 (COVID-19) pandemic has resulted in procedural-based specialties across the United States witnessing a sharp decline in their clinical volume and surgical cases. Objective To assess the impact of COVID-19 on neurosurgical, stroke neurology, and neurointerventional academic productivity. Methods The study compared the neurosurgical, stroke neurology, and neurointerventional academic output during the pandemic lockdown with the same time period in previous years. Editors from a sample of neurosurgical, stroke neurology, and neurointerventional journals provided the total number of original manuscript submissions, broken down by months, from the year 2016 to 2020. Manuscript submission was used as a surrogate metric for academic productivity. Results 8 journals were represented. The aggregated data from all eight journals as a whole showed that a combined average increase of 42.3% was observed on original submissions for 2020. As the average yearly percent increase using the 2016-2019 data for each journal exhibited a combined average increase of 11.2%, the rise in the yearly increase for 2020 in comparison was nearly fourfold. For the same journals in the same time period, the average percent of COVID-19 related publications from January to June of 2020 was 6.87%. Conclusion There was a momentous increase in the number of original submissions for the year 2020, and its effects were uniformly experienced across all of our represented journals.

Question: A 61-year-old man with a history of alcohol abuse presented with 2 years of intermittent episodes of abdominal distention associated with abdominal pain, vomiting, and decreased bowel movements. Symptoms would spontaneously resolve after a few days with episodes of diarrhea immediately following. He has had 50 pounds of unintentional weight loss in the past 2 years owing to these symptoms. He presented during one of these episodes triggered by air travel with symptoms for 10 days before presentation. A colonoscopy done overseas 5 years prior had reportedly revealed diverticulitis. His physical examination revealed a massively distended abdomen, tympanic to percussion with hypoactive bowel sounds (Figure A). Laboratory results were unremarkable, and a computed tomography scan showed diffused dilation of the colon up to 13cm with air fluid levels up to the rectosigmoid, without bowel wall thickening or small bowel dilation (Figure B). What is the cause of his recurrent episodes of abdominal distention? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. An exploratory laparotomy revealed massive colonic distention owing to colonic intussusception and stricturing mass at the rectosigmoid junction with adhesions to the bladder (Figure C). Subtotal colectomy with sigmoid colostomy was performed. Histopathologic examination of the colectomy surgical specimen revealed intussusception of the sigmoid colon owing to scar tissue from previous diverticulitis (Figure D). Intussusception is defined as the telescoping of a proximal segment of the gastrointestinal tract within the lumen of an adjacent segment. Intussusception is found primarily in the pediatric population, with 5% of all cases found in adults, and accounts for 1%–5% of all intestinal obstructions.1Azar T. Berger D.L. Adult intussusception.Ann Surg. 1997; 226: 134-138Crossref PubMed Scopus (696) Google Scholar Intussusception in children is usually benign and easily treated using pneumatic or hydrostatic reduction. However, in adults, 90% of cases can be viewed as secondary to a pathologic condition that serves as a lead point, such as carcinomas, polyps, diverticula, strictures, or benign neoplasms.2Weilbaecher D. Bolin J.A. Hearn D. et al.Intussusception in adults. Review of 160 cases.Am J Surg. 1971; 121: 531-535Abstract Full Text PDF PubMed Scopus (284) Google Scholar Scar tissue or adhesions as a lead point causing intussusception is rare, and to our knowledge, ours is the first case report of scar tissue from colonic diverticulitis causing intussusception. Symptoms of intussusception can include rectal bleeding, vomiting, abdominal pain, abdominal mass, diarrhea, and fever. Diagnosis is confirmed on abdominal imaging, including radiographs or computed tomography scans. Treatment includes barium or air enema but usually surgery is needed to free the portion of the trapped intestine and resect the lead point and intestinal necrosis. Intussusception cuts off the blood supply to the affected bowel and can lead to perforation, infection and necrosis and is fatal if left untreated in those that do not spontaneously resolve the intussusception.3Clark A.D. Hasso-Agopsowicz M. Kraus M.W. et al.Update on the global epidemiology of intussusception: a systematic review of incidence rates, age distributions and case-fatality ratios among children aged <5 years, before the introduction of rotavirus vaccination.Int J Epidemiol. 2019; 48: 1316-1326Crossref PubMed Scopus (26) Google Scholar Intussusception can be an uncommon complication of diverticulitis and requires early identification and treatment given the high associated mortality.