BACKGROUND: Experience with endoluminal flow diversion for the treatment of posterior circulation aneurysms is limited. PURPOSE: We sought to investigate factors associated with the safety and efficacy of this treatment by collecting disaggregated patient-level data from the literature. DATA SOURCES: PubMed, EMBASE, and Ovid were searched up through 2019 for articles reporting flow diversion of posterior circulation aneurysms. STUDY SELECTION: Eighty-four studies reported disaggregated data for 301 separate posterior circulation aneurysms. DATA ANALYSIS: Patient, aneurysm, and treatment factors were collected for each patient. Outcomes included the occurrence of major complications, angiographic occlusion, and functional outcomes based on the mRS.DATA SYNTHESIS: Significant differences in aneurysm and treatment characteristics were seen among different locations. Major complications occurred in 22%, angiographic occlusion was reported in 65% (11.3 months of mean follow-up), and good functional outcomes (mRS 0-2) were achieved in 67% (13.3 months of mean follow-up). Multivariate analysis identified age, number of flow diverters used, size, and prior treatment to be associated with outcome measures. Meta-analysis combining the current study with prior large nondisaggregated series of posterior circulation aneurysms treated with flow diversion found a pooled incidence of 20% (n ¼ 712 patients) major complications and 75% (n ¼ 581 patients) angiographic occlusions. LIMITATIONS:This study design is susceptible to publication bias. Use of antiplatelet therapy was not uniformly reported. CONCLUSIONS:Endoluminal flow diversion is an important tool in the treatment of posterior circulation aneurysms. Patient age, aneurysm size, prior treatment, and the number of flow diverters used are important factors associated with complications and outcomes.ABBREVIATIONS: aOR ¼ adjusted OR; FD ¼ flow diverter; PCA ¼ posterior cerebral artery; VBJ ¼ vertebrobasilar junction E ndoluminal flow diversion is a well-established treatment for cerebral aneurysms, but most flow diverters (FDs) have been approved for the treatment of anterior circulation aneurysms. 1 Posterior circulation aneurysms comprise 10%-15% of all cerebral aneurysms, 2 and some of the first cases of flow diversion in the

OBJECTIVE While sporadic peripheral schwannomas (SPSs) are generally well treated with surgery, their biology is not well understood. Consequently, treatment options are limited. The aim of this study was to provide a comprehensive description of SPS. The authors describe clinicopathological features and treatment outcomes of patients harboring these tumors, and they assess expression of biomarkers using a clinically annotated tissue microarray. Together, these data give new insight into the biology and management of SPS. METHODS Patients presenting with a primary SPS between 1993 and 2011 (n = 291) were selected from an institutional registry to construct a clinical database. All patients underwent follow-up, and short- and long-term outcomes were assessed. Expression of relevant biomarkers was assessed using a new tissue microarray (n = 121). RESULTS SPSs were generally large (mean 5.5 cm) and frequently painful at presentation (55%). Most patients were treated with surgery (80%), the majority of whom experienced complete resolution (52%) or improvement (18%) of their symptoms. Tumors that were completely resected (85%) did not recur. Some patients experienced short-term (16%) and long-term (4%) complications postoperatively. Schwannomas expressed higher levels of platelet-derived growth factor receptor-β (2.1) than malignant peripheral nerve sheath tumors (MPNSTs) (1.5, p = 0.004) and neurofibromas (1.33, p = 0.007). Expression of human epidermal growth factor receptor-2 was greater in SPSs (0.91) than in MPNSTs (0.33, p = 0.002) and neurofibromas (0.33, p = 0.026). Epidermal growth factor receptor was expressed in far fewer SPS cells (10%) than in MPNSTs (58%, p < 0.0001) or neurofibromas (37%, p = 0.007). SPSs more frequently expressed cytoplasmic survivin (66% of tumor cells) than normal nerve (46% of cells), but SPS expressed nuclear survivin in fewer tumor cells than in MPNSTs (24% and 50%, respectively; p = 0.018). CONCLUSIONS Complete resection is curative for SPS. Left untreated, however, these tumors can cause significant morbidity, and not all patients are candidates for resection. SPSs express a pattern of biomarkers consistent with the dysregulation of the tumor suppressor merlin observed in neurofibromatosis Type 2-associated schwannomas, suggesting a shared etiology. This SPS pattern is distinct from that of other tumors of the peripheral nerve sheath.

BACKGROUND AND IMPORTANCE:Penetrating missile injury to the carotid arteries may lead to catastrophic hemorrhagic and/or ischemic complications. The incidence of carotid injury in patients with penetrating cervical trauma (PCT) is 11% to 13%, with most cases involving the common carotid artery (73%), followed by the internal carotid artery (ICA) (22%) and external carotid artery (5%). Approximately 50% of PCT cases result in mortality, with specific injury to the carotid arteries carrying nearly a 100% mortality rate. Although historically limited because most patients do not survive these serious injuries, treatment has become more feasible with advancements in endovascular techniques and technologies.CLINICAL PRESENTATION:A young man presented to our trauma center after sustaining a gunshot wound to the right neck, leading to significant hemorrhage and ultimately a Biffl grade IV ICA injury. He was taken emergently to the operating room for cervical exploration and hemostasis. A computed tomography stroke study performed after initial stabilization revealed complete right ICA occlusion with increased time-to-peak in the right hemisphere. The patient was resuscitated to maintain sufficient cerebral perfusion pressure. Later, once hemodynamic stability was achieved, the patient underwent confirmatory angiography, followed by complete ICA revascularization using a balloon guide catheter to achieve flow arrest and placement of multiple carotid stents. He made a good neurological recovery.CONCLUSION:Endovascular carotid artery revascularization may be performed successfully in the subacute phase after PCT. The use of flow arrest obtained with a balloon guide catheter assists in preventing catastrophic hemorrhage in the event of rupture.