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Jeffrey Steinberg, Vincent Cheung, Gunjan Goel, J. Scott Pannell, Javan Nation and Alexander Khalessi

Although there have been reports of carotid artery pseudoaneurysm formation after adenoidectomy and/or tonsillectomy secondary to iatrogenic injury, there are no case reports of successful endovascular reconstruction of the injured artery in the pediatric population. In most pediatric cases, the internal carotid artery (ICA) is sacrificed. The authors report on a 6-year-old girl who presented with odynophagia, left-sided Horner's syndrome, hematemesis, and severe anemia 6 months after a tonsillectomy. On examination she was found to have a pulsatile mass along the left posterior lateral oropharynx, and imaging demonstrated a dissection of the extracranial left ICA and an associated pseudoaneurysm. The lesion was managed endovascularly with stent-assisted coil embolization and ICA reconstruction. The child had a somewhat complicated postoperative course, requiring additional coil embolization for treatment of a minor recurrence of the pseudoaneurysm at 5 months after the initial treatment and then presenting with extrusion of a portion of the coil mass into the oropharyngeal cavity a year later. She underwent surgical removal of the extruded coils and repair of the defect and has since been free of symptoms or signs of recurrence.

The authors conclude that this strategy definitively protected the patient against an oral exsanguination or aspiration event secondary to aneurysm rupture and reduced her risk of stroke by preserving vessel patency and caliber. Moreover, they note that covered stent reconstruction surrenders endovascular access and cannot immediately provide these benefits.

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David R. Santiago-Dieppa, Brian R. Hirshman, Arvin Wali, J. Scott Pannell, Yasaman Alam, Scott Olson, Vincent J. Cheung, Jeffrey A. Steinberg, Mihir Gupta and Alexander A. Khalessi

OBJECTIVE

Carotid artery stenting (CAS) has antihypertensive effects, but the durability and degree of this response remain variable. The authors propose that this clinical variability is a function of the presence or absence of a complete circle of Willis (COW). Incomplete COWs perfuse through a higher-resistance pial collateral pathway, and therefore patients may require a higher mean arterial pressure (MAP). Carotid artery revascularization in these patients would reduce the end-organ collateral demand that has been hypothesized to drive the MAP response.

METHODS

Using a retrospective, nonrandomized within-subject case-control design, the authors compared the postoperative effects of CAS in patients with and without a complete COW by using changes in MAP and antihypertensive medication as end points. They recorded MAP and antihypertensive medications 3 months prior to surgery, preoperatively, immediately postoperatively, and at the 3-month follow-up.

RESULTS

Data were collected from 64 consecutive patients undergoing CAS. Patients without a complete COW (25%) were more likely to demonstrate a decrease in BP response to stenting (i.e., a drop in MAP of 10 mm Hg and/or a reduction or cessation of BP medications at 3 months postoperatively). Of the patients in the incomplete COW cohort, 75% had this outcome, whereas of those in the complete COW cohort, only 41% had it (p < 0.041). These findings remained statistically significant in a logistic regression analysis for possible confounders (p < 0.024). A receiver operating curve analysis of preoperative data indicated that a MAP > 96.3 mm Hg was 55.5% sensitive and 57.4% specific for predicting a complete COW and that patients with a MAP > 96.3 mm Hg were more likely to demonstrate a good MAP decrease following CAS (p < 0.0092).

CONCLUSIONS

CAS is associated with a significant decrease in MAP and/or a reduction/cessation in BP medications in patients in whom a complete COW is absent.

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Peter Abraham, J. Scott Pannell, David R. Santiago-Dieppa, Vincent Cheung, Jeffrey Steinberg, Arvin Wali, Mihir Gupta, Robert C. Rennert, Roland R. Lee and Alexander A. Khalessi

OBJECTIVE

In vivo and in vitro studies have demonstrated histological evidence of iatrogenic endothelial injury after stent retriever thrombectomy. However, noncontrast vessel wall (VW)–MRI is insufficient to demonstrate vessel injury. Authors of this study prospectively evaluated iatrogenic endothelial damage after stent retriever thrombectomy in humans by utilizing high-resolution contrast-enhanced VW-MRI. Characterization of VW-MRI changes in vessels subject to mechanical injury from thrombectomy may allow better understanding of the biological effects of this intervention.

METHODS

The authors prospectively recruited 11 patients for this study. The treatment group included 6 postthrombectomy patients and the control group included 5 subjects undergoing MRI for nonvascular indications. All subjects were evaluated on a Signa HD× 3.0-T MRI scanner with an 8-channel head coil. Both pre- and postcontrast T1-weighted Cube VW images as well as MR angiograms were acquired. Sequences obtained for evaluation of the brain parenchyma included diffusion-weighted, gradient echo, and T2-FLAIR imaging. Two independent neuroradiologists, who were blinded to the treatment status of each patient, determined the presence of VW enhancement. Patient age, National Institutes of Health Stroke Scale score on presentation, location of occlusion, stroke etiology, type of device used, number of device deployments, Thrombolysis in Cerebral Infarction (TICI) reperfusion score, stroke volume, and 90-day modified Rankin Scale score were also noted.

RESULTS

Postcontrast T1-weighted VW enhancement was detected in the M2 segment in 100% of the thrombectomy patients, in the M1 segment in 83%, and in the internal carotid artery in 50%. One patient also demonstrated A1 segment enhancement, which was attributable to thrombectomy treatment of that vessel segment during the same procedure. None of the control patients demonstrated VW enhancement of their intracranial vasculature on T1-weighted images.

CONCLUSIONS

The study findings suggest that VW injury incurred during stent retriever thrombectomy can be reliably detected utilizing contrast-enhanced 3-T VW-MRI. The results further demonstrate that endothelial injury is associated with oversizing of stent retrievers relative to the treated vessel. Further studies are needed to evaluate the clinical significance of endothelial injury and to characterize the differential effects of various devices.

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Reid Hoshide, Robert C. Rennert, Carlos E. Sanchez, Joel R. Martin, Vincent J. Cheung, Gayle Gyles and Michael L. Levy

Irrigation during intraventricular endoscopic surgery is critical for visualization, with normal intracranial pressure maintained by balancing fluid ingress and egress. Although irrigation is typically achieved through manual manipulation of inexact stopcocks, the authors have developed a rate-controlled, foot pedal–activated system for precise intraventricular irrigation by using a standard irrigating bipolar electrocautery machine.

This study is a retrospective review of patients who underwent endoscopic intraventricular surgery between January 1, 2018, and September 25, 2019, in which this irrigation system was used. Important components of this system include a bipolar module irrigation regulator that is set to a desired rate, a secure connection of the bipolar irrigation tubing to the endoscope, and one or more open egress ports on the endoscope for passive fluid drainage. Nineteen consecutive patients were identified on review (average age ± SD, 4.3 ± 4.1 years). Procedures performed included third ventriculostomies (n = 10); arachnoid/choroid cyst fenestrations/resections (n = 3); biopsy/tumor resection (n = 1); and combined procedures (n = 5). Foot pedal–controlled irrigation provided visualization of all intraventricular structures. A single operator was able to control the endoscope, endoscopic instruments, and irrigation, with assistance as indicated for more complex maneuvers. There were no perioperative complications. Because this setup is easily constructed from a standard irrigating bipolar machine, delivers precise irrigation flow rates, and facilitates a single-surgeon bimanual technique, these data support the utility of foot-controlled irrigation for endoscopic intraventricular surgery.

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David D. Gonda, Vincent J. Cheung, Karra A. Muller, Amit Goyal, Bob S. Carter and Clark C. Chen

Differentiating between low-grade gliomas (LGGs) of astrocytic and oligodendroglial origin remains a major challenge in neurooncology. Here the authors analyzed The Cancer Genome Atlas (TCGA) profiles of LGGs with the goal of identifying distinct molecular characteristics that would afford accurate and reliable discrimination of astrocytic and oligodendroglial tumors. They found that 1) oligodendrogliomas are more likely to exhibit the glioma-CpG island methylator phenotype (G-CIMP), relative to low-grade astrocytomas; 2) relative to oligodendrogliomas, low-grade astrocytomas exhibit a higher expression of genes related to mitosis, replication, and inflammation; and 3) low-grade astrocytic tumors harbor microRNA profiles similar to those previously described for glioblastoma tumors. Orthogonal intersection of these molecular characteristics with existing molecular markers, such as IDH1 mutation, TP53 mutation, and 1p19q status, should facilitate accurate and reliable pathological diagnosis of LGGs.