Preoperative Transarterial Embolization Research Articles

Preoperative Embolization in Carotid Body Tumor Surgery—Benefit or Risk?

Carotid body tumors (CBTs) are rare head and neck paragangliomas with an incidence of 0.03% of all tumors. Risk of malignant transformation is 5% to 10%. Preoperative transarterial embolization can facilitate resection of the highly vascularized tumors, yet the benefit of this procedure has not yet been demonstrated clearly. The purpose of this study was to assess the results of preoperative transarterial embolization with focus on patient safety and on selection criteria for individual treatment decisions. All consecutive patients operated on for CBTs from 1988 to 2018 were analyzed. After prospective collection in a dedicated database, data were analyzed retrospectively. Diagnosis was confirmed by ultrasound and magnetic resonance imaging. After approval by the university ethics committee and informed consent, genetic testing for mutations of the gene encoding succinate dehydrogenase was initiated routinely in 2006. Preoperative embolization was performed by experienced interventional radiologists using microcatheter techniques. A total of 80 patients underwent resection of 91 CBTs (57 women, 23 men; age, 24-86 years; mean age, 55.7 ± 16.4 years ). In four patients, a tumor recurrence or lymph node infiltration was diagnosed (malignant CBT). Genetic testing detected succinate dehydrogenase mutations in 47% (28/57 patients). Tumor diameter was 1.1 to 7.2 cm. Fourteen patients with a mean tumor diameter of 4.6 cm (range, 2.0-6.2 cm) underwent preoperative embolization after interdisciplinary discussion. In one patient (75-year-old man), embolization could not be completed because of development of a temporary neurologic deficit during the procedure (ipsilateral transitory ischemic attack). No other adverse effects due to embolization were observed. Surgery was performed 24 to 48 hours after intervention. Intraoperative blood loss and operating times did not differ significantly between patients with or without preoperative embolization. However, the subjective impression of the operating surgeons was that tumor resection was facilitated by embolization. Preoperative embolization in CBTs is a safe and effective preoperative strategy in large carotid paragangliomas, rarely leading to neurologic complications. Criteria for optimized selection of patients to develop individualized preoperative strategies and clear recommendations on candidates for embolization have yet to be identified. Because of the rarity of the tumor, a randomized trial is difficult to organize.

Complications after Liver Transplant Related to Preexisting Conditions: Diagnosis, Treatment, and Prevention.

Diagnostic imaging after orthotopic liver transplant focuses primarily on depicting complications related to surgical hepatic vascular and biliary anastomoses. Less common preexisting vascular conditions include congenital anatomic variants, atherosclerosis, chronic portal venous thrombosis, splenic artery and variceal steal phenomena, and transarterial embolization (TAE) for hepatocellular carcinoma (HCC). If unappreciated or left untreated preoperatively, these conditions negatively impact the transplant by impairing hepatic arterial or portal vascular inflow. Many of the complications related to preexisting vascular conditions can be prevented or mitigated by proper performance and careful evaluation of preoperative imaging studies. The authors describe the diagnosis and treatment of complications arising from narrowing of the celiac axis by atherosclerosis and the median arcuate ligament, variant anatomy of the hepatic artery, insufficiency of the portal vein requiring surgical conduits, and large varices or an enlarged splenic artery and spleen that may steal blood and compromise hepatic arterial or venous inflow. While preoperative evaluation primarily involves CT and MRI, postoperative diagnosis involves screening with sonography and confirmation with other modalities. We propose the use of a preoperative checklist of vascular status and measurements in patients undergoing liver transplant. Reports of imaging studies in recipients after transplant should include details of surgical vascular anastomoses and conduits, any history of HCC and preoperative TAE, details of the preoperative α-fetoprotein levels, and any unusual procedures or pathologic findings in the explanted liver that may affect postoperative surveillance. The authors review the pretransplant imaging evaluation of vascular and HCC issues that may affect surgical outcomes and methods to help recognize complications after transplant that can arise from these conditions.©RSNA, 2020.

Pre-Operative Embolisation of Musculoskeletal Tumours - A Single Centre Experience.

Introduction:The management of musculoskeletal tumours is complex and requires a multi-disciplinary approach. Preoperative embolisation can be often employed to reduce intra-operative blood loss and complication rates from surgery. We report our experience with the safety, technical success and efficacy of pre-operative embolisation in musculoskeletal tumours.Materials and Methods:Thirteen consecutive patients who underwent pre-operative embolisation of a musculoskeletal tumour followed by surgical intervention at our institution from May 2012 to January 2016 were enrolled into the study. Patient demographics, tumour characteristics, embolisation techniques and type of surgery were recorded. Technical success of embolisation, amount of blood loss during surgery and transfusion requirements were estimated.Results:There were five female and eight male patients who underwent pre-operative embolisation during the study period. The age ranged between 16 to 68 years, and the median age was 54. Technical success was achieved in all patients. Mean intra-operative blood loss was 1403ml, with a range of 150ml to 6900ml. Eight patients (62%) required intra-operative blood products of packed red blood cells and fresh frozen plasma. No major complications occurred during embolisation.Conclusion:Pre-operative trans-arterial embolisation is feasible and safe for a variety of large and hypervascular musculoskeletal tumours. Our small series suggests that preoperative embolisation could contribute to the reduction of the intra-operative and post-operative blood product transfusion. It should be considered as a pre-operative adjunct for major tumour resections with a high risk of bleeding. The use of the haemoglobin gap complemented the assessment of perioperative blood loss.

Abstract No. 411 The role of preoperative transarterial embolization in primary and secondary bone tumors

Abstract No. 411 The role of preoperative transarterial embolization in primary and secondary bone tumors

Abstract No. 399 Perioperative blood loss after embolization of hypervascular musculoskeletal tumors: a single-center 10-year experience

To assess outcomes following transarterial embolization of hypervascular bony tumors in patients undergoing orthopedic resection at our institution over a 10-year period. From April 2008 to August 2018, 73 patients with (59 males; mean age 58.1 years) with musculoskeletal (MSK) neoplasms presented for embolization for preoperative devascularization prior to orthopedic surgery and were retrospectively reviewed. Data collected includes demographic data, medical history, pertinent labs (i.e., hemoglobin levels), procedural information, surgical details (estimated blood loss (EBL), intraoperative transfusion), hospital course, and pathology. Fifty-eight patients (47 men, 11 women, range 21-84 years) were included in our analysis. Fifteen patients were excluded from this study (3 patients underwent angiography but were not embolized due to lack of large feeding branch vessel; 12 patients did not proceed to surgery after embolization). The median EBL was 500 mL (range, 100-3000). There was no difference in EBL between RCC (719.6 ± 626.1) and non-RCC groups (855.6 ± 657.5; P = 0.44). The median intraoperative transfusion requirement was 1.0 unit (range, 0-8 ± 2.06). 15.8% of patients required postoperative transfusion (median, 1.5 units; range 1-3). Of patients that received peri-operative transfusion, there was no difference in transfusion requirement in RCC and non-RCC groups (P = 0.88). Of the patients that did not get transfusions, the mean decrease in pre and postoperative hemoglobin was 1.41 g/dL (± 0.51g/dL). There were no complications related to non-target embolization. Preoperative transarterial embolization of hypervascular MSK neoplasms appears to be safe and effective in minimizing peri- and postoperative bleeding while keeping transfusion requirements low.

Chapter 14 - Anatomy of petrous face

The anatomy of the petrous face of the temporal bone, also known as the petrous pyramid, should be carefully examined to understand the location of, blood supply to, and venous drainage of meningiomas in this area (42%-59% of posterior fossa meningiomas). The petrous face is located in the skull base between the sphenoid and occipital bones. It consists of a base that joins the mastoid laterally and an apex that extends anteromedially to form the foramen lacerum. The anatomy can be divided into three surfaces: anterior/superior, posterior, and inferior. The anterior/superior surface is a continuation of the posteromedial portion of the middle cranial fossa with boundaries extending from the arcuate eminence to the petrous apex. The posterior surface is a continuation of the front part of the posterior cranial fossa with the internal auditory meatus at its center. The inferior surface contains foramina that transmit important vessels and cranial nerves. The vascular anatomy of the petrous face is also described, including branches of the carotid artery and vertebrobasilar systems. It is imperative to understand potential anastomotic routes between extracranial and intracranial arteries, as well as arterial supply to cranial nerves, to facilitate preoperative transarterial embolization of meningiomas and avoid neurologic complications during surgery.

Endovascular Management of Paragangliomas

AbstractBackground: Paragangliomas of head and neck are highly vascular tumors, which coupled their surgical excision with high morbidity. Pre-operative transarterial super selective embolization markedly improved safety of their surgical excision.Patients and Methods: This is a retrospective non-randomized clinical and angiographic study of all ten patients with paragangliomas who undergone pre-operative emboliza-tion in Department of Neurosurgery-Tanta University between 2010 and 2016.Results: The ten patients had 11 paragangliomas. 80% of patients were females. The average age of patients was 47 years. All patients had pain and pulsatile tinnitus at diagnosis. Paragangliomas subtypes comprised 8 temporal, 2 carotid body and one vagale tumors. The average reduction of para-ganglioma vascularity after embolization was 80%.Conclusions: Pre-operative transarterial embolization of head and neck paragangliomas is a very safe and effective adjuvant to surgical excision.

Transient neurologic deficit with complete recovery due to cervical spinal cord infarction after preoperative embolization for metastatic lesion of malignant pheochromocytoma at proximal thoracic spine

Spinal cord infarction after preoperative transarterial embolization for metastatic spinal lesions is uncommon and usually leads to complete paralysis. Transient neurologic deficit due to spinal cord infarction after preoperative embolization for spinal metastases has never been reported in the literature. A 30-year-old female patient was diseased with malignant pheochromocytoma and multiple metastases to lung and bones. She suffered from refractory pain at upper back and numbness at her body below xiphoid process but no motor deficit was noted at extremities. Magnetic resonance imaging (MRI) revealed paraspinal and epidural lesions originating from T2 to T4 vertebrae with compression to spinal cord. Preoperative embolization was executed to the spinal metastases with the intent to reduce intraoperative bleeding. Embolization procedure was performed to bilateral costocervical trunk, 3rd and 4th intercostal arteries with 400 μm Embozene® microsphere under local anesthesia. The procedure was discontinued immediately after development of severe hypertension that might be related to the pheochromocytoma and was treated with intravenous antihypertensive drug. There was no neurologic deficit until 6.5 hours after the procedure when weakness at right lower extremity and hypesthesia at left arm developed. Emergent MRI showed focal infarcts in spinal cord at right aspect of C5 and left C4 levels. With adequate hydration but no administration of steroid, muscle power gradually recovered in a few hours. Posterior instrumentation, neural decompression and tumor debulking were performed 2 days after embolization as scheduled. One week after the event of spinal cord infarction, she could stand up and walk without aid. Even though it is rare, spinal cord infarction is an important differential diagnosis for sudden decrease of muscle power after preoperative embolization for spinal metastases. Although complete paralysis is more common, transient neurologic deficit with complete recovery could happen in patients with minor infarcts in the spinal cord.

Transient neurologic deficit with complete recovery due to cervical spinal cord infarction after preoperative embolization for metastatic lesion of malignant pheochromocytoma at proximal thoracic spine

Spinal cord infarction after preoperative transarterial embolization for metastatic spinal lesions is uncommon and usually leads to complete paralysis. Transient neurologic deficit due to spinal cord infarction after preoperative embolization for spinal metastases has never been reported in the literature. A 30-year-old female patient was diseased with malignant pheochromocytoma and multiple metastases to lung and bones. She suffered from refractory pain at upper back and numbness at her body below xiphoid process but no motor deficit was noted at extremities. Magnetic resonance imaging (MRI) revealed paraspinal and epidural lesions originating from T2-4 vertebrae with compression to spinal cord. Preoperative embolization was executed to the spinal metastases with the intent to reduce intraoperative bleeding. Embolization procedure was performed to bilateral costocervical trunk, 3rd and 4th intercostal arteries with 400 μm Embozene® microsphere under local anesthesia. The procedure was discontinued immediately after development of severe hypertension that might be related to the pheochromocytoma and was treated with intravenous antihypertensive drug. There was no neurologic deficit until 6.5 hours after the procedure when weakness at right lower extremity and hypesthesia at left arm developed. Emergent MRI showed focal infarcts in spinal cord at right aspect of C5 and left C4 levels. With adequate hydration but no administration of steroid, muscle power gradually recovered in a few hours. Posterior instrumentation, neural decompression and tumor debulking were performed 2 days after embolization as scheduled. One week after the event of spinal cord infarction, she could stand up and walk without aid. Even though it is rare, spinal cord infarction is an important differential diagnosis for sudden decrease of muscle power after preoperative embolization for spinal metastases. Although complete paralysis is more common, transient neurologic deficit with complete recovery could happen in patients with minor infarcts in the spinal cord.

Current application of endovascular interventions in surgical management of carotid body tumor

Carotid body tumors (CBTs) are rare neoplasms at the carotid bifurcation. Surgical excision is currently the only curable treatment for CBTs but is associated with high incidence of morbidities and mortality, due to the hyper-vascularity and proximity to carotid vessels and cranial nerves of the tumors. In the last decades, endovascular interventions, including preoperative trans-arterial embolization and carotid stents, have been utilized in surgical excision of CBTs with the attempt to reduce perioperative complications and improve surgical outcomes. However, controversial results have been reported with regard to the efficacy of such techniques. This review summarized the current application of endovascular interventions in surgical treatment of CBTs, with emphasis on their impacts on surgical conducting and perioperative complications.

Pre-operative embolisation of spinal tumours: neither neglect the neighbour nor blindly follow the gold standard.

A large variety of vertebral tumours undergoes transarterial embolisation (TAE) prior to surgery. However, the subsequent intra-operative blood loss is unpredictable. This retrospective analysis, aims to determine the impact of various factors that may potentially influence the estimated intra-operative blood loss (EBL) in these patients. The study included 56 consecutive patients with spinal tumours who underwent pre-operative TAE. Demographic information, treatment history, tumour type, MRI characteristics, angiographic appearance, embolisation technique and surgical invasiveness were correlated with EBL using univariate and multivariate analysis. Mean EBL was 1317mls. On univariate analysis, haematological/primary tumours, MRI hypervascularity and selective embolisation were significantly (P < 0.05) associated with increased EBL. A total angiographic devascularisation and embolisation of additional segments above and/or below the involved level were significantly associated with decreased EBL. There was no significant association with hypervascular angiographic appearance or surgical invasiveness. MRI and angiographic hypervascularity were not entirely concordant, especially for the category of moderately vascularised metastases. After multivariate analysis, MRI hypervascularity (1434 vs. 929mls, P = 0.018) and embolisation of additional segments (1082 vs. 1607mls, P = 0.003) remained significantly correlated with EBL. In conclusion, during pre-operative TAE of spinal tumours, routine angiographic interrogation of additional levels above and below the involved segment should be made, with a low threshold for embolising them, if safely performable. Compared to angiographic gold standard, MRI hypervascularity is probably a better predictor of EBL.

Impact of preoperative transarterial embolization of carotid body tumor: A single center retrospective cohort experience

ObjectiveTo evaluate the feasibility and efficacy of preoperative hyperselective transarterial embolization in carotid body tumor resection. MethodsRetrospectively analyze the clinical feature, imaging examination, treatment strategy and prognosis of 29 carotid body tumor patients from January 2006 to January 2016. According to whether to carry out the pre-operative transarterial embolization, the patients were classified into embolization group and non-embolization group. The blood loss, operative time and perioperative complications were compared between the 2 groups. Results29 carotid body tumors were resected. The median of blood loss was 80 mL in embolization group and 200 mL in non-embolization group, the difference was statistically significant (P = 0.001). The median of operative time was 120 min in embolization group and 160 min in non-embolization group, the difference was statistically significant (P = 0.006). No death, paralysis or ectopic embolism occurred in the study population. 4 patients in embolization group and 4 in non-embolization group suffered from cranial nerve injury. ConclusionSurgical resection of carotid body tumor is safe and reliable, which is the first choice in the treatment of carotid body tumor. Preoperative transaterial hyperselective embolization can significantly reduce blood loss and shorten operative time, but it dose not decrease the incidence of cranial never injury.

Not All Patients Undergoing Stabilization of Impending Pathologic Fractures for Renal Cell Carcinoma Metastases to the Femur Need Preoperative Embolization.

Preoperative transarterial embolization has been utilized in the surgical treatment of metastatic renal cell carcinoma of the femur to decrease perioperative blood loss. However, few studies have documented its efficacy in decreasing the proportion of patients receiving transfusions in the setting of prophylactic treatment of impending pathologic femur fractures. In a population of patients with metastatic renal cell carcinoma of the femur who underwent prophylactic fixation, the purpose of this study was to quantify and compare the proportion of patients who received at least one transfused unit of blood between a group treated with preoperative embolization and a group without preoperative embolization. A retrospective study was performed using a Medicare claims-based database. International Classification of Diseases, 9 Revision and Current Procedural Terminology codes were used to identify 1285 patients with metastatic renal cell carcinoma of the femur who underwent prophylactic fixation. The proportion of patients who received one or more blood transfusions was compared between 135 patients who underwent preoperative embolization and a group of 1150 concurrent control patients who did not undergo preoperative embolization. The control group was older than the embolization group, with 44% of these patients > 75 years old and 33% of the embolization group > 75 years. There was no difference in the female:male ratio between groups. Statistical comparisons of outcomes related to transfusion percentages were performed using Pearson chi square analysis with p < 0.05 considered significant. With the numbers available, we had 80% power to detect a difference in the percentage of patients transfused of 11% between the study groups at α = 0.05. No difference in transfusion percentage was observed between preoperative transarterial embolization (41 of 135 [30%]) and the control group (359 of 1150 [31%]; relative risk, 0.973; 95% confidence interval, 0.743-1.274; p = 0.84). The percentage of all patients who received a transfusion was 31% (400 of 1285). Preoperative embolization may not be mandatory in the prophylactic treatment of metastatic renal cell carcinoma of the femur, as demonstrated by the 69% of patients who received zero units of blood despite not receiving embolization. However, assessment of the efficacy of embolization in decreasing blood loss in the current study is limited as a result of biases associated with the database design of the study; the decision of whether to send a patient for embolization should be made on a case-by-case basis. The current study does not identify specific risk factors that should factor into this decision and underscores the need for further research in this regard. A plausible future research design to account for the low numbers and selection bias that limited the current study as well as the existing studies might be a multicenter, retrospective case-control study. Level III, therapeutic study.

Preoperative Trans-Arterial Embolization and Surgical Resection for Giant Liver Hemangioma: A Multidisciplinary Approach

Preoperative Trans-Arterial Embolization and Surgical Resection for Giant Liver Hemangioma: A Multidisciplinary Approach

Preoperative transarterial particulate embolization of juvenile angiofibroma with intracranial extension: Technical and clinical outcomes

PurposeThis retrospective study was constructed to assess the beneficial effects of preoperative transarterial particulate embolization of juvenile angiofibroma (JA) with intracranial extension in terms of intraoperative blood loss and local tumor recurrence. Patients and MethodsThis study included 20 male patients (mean age±SD: 14.6±7.2years) with radiologically documented and histologically proved JA. All patients had intracranial extension and underwent surgical resection of the tumor after preoperative transarterial particulate embolization. The amount of blood loss was estimated and follow up scans were assessed for tumor recurrence. ResultsThe mean amount of intra-operative blood loss was 560ml and the mean amount of blood transfusion was 944.4ml. Local residue/recurrence of tumor was seen in 5 patients (5/20); two patients with intracranial residual tumor (2/20), one patient with intracranial recurrence (1/20) and 2 patients (2/20) with extracranial recurrence. The technique of embolization was safe with no procedure related mortality. Minor complications were seen in all patients and major complication only in one patient. ConclusionPreoperative transarterial particulate embolization of JA with intracranial extension helped to perform surgery with mild amount of blood loss compared to the literature.

Features of sinonasal hemangioma: A retrospective study of 31 cases

ObjectiveAlthough hemangiomas are common lesions of the head and neck, sinonasal hemangiomas are rare. The purpose of this study was to analyze the clinical features (sex, age, symptoms, and size and anatomical location of the lesion) and the histological findings of sinonasal hemangioma cases, to assess preoperative transarterial embolization, and to evaluate the outcome (recurrence or no recurrence) of endoscopic sinus surgery. MethodsClinical records of 31 patients who underwent endoscopic sinus surgery for resection of sinonasal hemangioma between January 2010 and June 2015 were retrospectively reviewed. ResultsThe study group consisted of 19 men and 12 women. Mean age was 53.3±15.9years. The principal symptom was epistaxis (81%). Mean tumor size was 12.6±8.2mm. The most common origin of hemangioma was the inferior turbinate (45%), followed by the nasal septum (39%), and, in both locations, the origin had a tendency to be located in the anterior portion. Thirty-one specimens were histologically categorized as 9 cavernous hemangiomas and 22 capillary hemangiomas. Preoperative transarterial embolization was performed in 2 cases. Only one recurrence was observed among 31 cases. In the recurrent case, the hemangioma of the nasal septum was resected during pregnancy. ConclusionAccording to our results, the transnasal endoscopic approach can be useful for the resection of sinonasal hemangioma. However, sinonasal hemangioma in connection with pregnancy must be addressed with care to decide the appropriate time for treatment.

Direct Puncture Embolization for Endonasal Resection of Juvenile Nasopharyngeal Angiofibroma Supplied by Internal Carotid Artery

Introduction: Juvenile nasopharyngeal angiofibromas (JNAs) have a propensity for major blood loss when approached surgically. Use of preoperative transarterial (TA) or direct tumor puncture (DTP) embolization has been shown to reduce blood loss during resection. It is critical to determine the embolization technique that best suits a specific tumor prior to resection to optimize surgical conditions by minimizing intraoperative bleeding. We present a case report that underscores the importance of this treatment approach and begs for the development of such an algorithm.

Pre-operative Embolization for Bone Tumors; Single Center Experience

Objective: The purpose of this study was to report our experience with 35 patients, presenting with primary or secondary bone tumors, who underwent pre-operative transarterial embolization in our institution. Methods: Pre-operative transarterial embolizations between 2009 and 2013 were retrospectively reviewed in 35 patients (20 men and 15 women), with a mean age of 49.29 years, range 15-79 years. Medical records were reviewed to obtained patient’s data, histological diagnosis, anatomical site, post embolization complication, interval between embolization and surgery, operative procedure and operation time. Estimated blood losses (EBL) were obtained from operative notes or anesthetic notes. Results: Thirty-five patients had a total of 43 procedures in 5 years period, in which five patients underwent twice and one patient underwent four pre-operative embolizations. All 43 pre-operative embolization procedures were technically successful and underwent surgery after embolization, with a mean of 2.7 days, range 0-15 days. No patient experienced embolization associated major complication. The mean estimated blood loss was 2,915 mL (range 20-14,000 mL). Conclusion: Pre-operative transarterial embolization of both primary and secondary bone tumors was safe and effective and can help to reduce intra-operative blood loss particularly when superselective embolization was performed. Blood loss during surgery increased if the operation was not performed within 3 days after embolization due to re-canalization and angiogenesis.

Lower limb giant plexiform neurofibroma: preoperative evaluation and surgical planning

Few cases of lower limb giant plexiform neurofibroma have been reported in literature and there are no available guidelines for defining its preoperative evaluation and surgical approach . Lower limb giant plexiform neurofibroma is a rare condition that requires clinical and radiological preoperative evaluation, mainly with MRI. Surgery is the only treatment with no preoperative trans-arterial embolization or vessel ligation. Early excision of superficial lesions may prevent further progression.

Initial experience with dual-lumen balloon catheter injection for preoperative Onyx embolization of skull base paragangliomas.

OBJECT Paragangliomas are highly vascular head and neck tumors for which preoperative embolization is often considered to facilitate resection. The authors evaluated their initial experience using a dual-lumen balloon to facilitate preoperative embolization in 5 consecutive patients who underwent preoperative transarterial Onyx embolization assisted by the Scepter dual-lumen balloon catheter between 2012 and 2014. OBJECT The authors reviewed the demographic and clinical records of 5 patients who underwent Scepter-assisted Onyx embolization of a paraganglioma followed by resection between 2012 and 2014. Descriptive statistics of clinical outcomes were assessed. RESULTS Five patients (4 with a jugular and 1 with a vagal paraganglioma) were identified. Three paragangliomas were embolized in a single session, and each of the other 2 were completed in 3 staged sessions. The mean volume of Onyx used was 14.3 ml (range 6-30 ml). Twenty-seven vessels were selectively catheterized for embolization. All patients required selective embolization via multiple vessels. Two patients required sacrifice of parent vessels (1 petrocavernous internal carotid artery and 1 vertebral artery) after successful balloon test occlusion. One patient underwent embolization with Onyx-18 alone, 2 with Onyx-34 alone, and 1 with Onyx-18 and -34. In each case, migration of Onyx was achieved within the tumor parenchyma. The mean time between embolization and resection was 3.8 days (range 1-8 days). Gross-total resection was achieved in 3 (60%) patients, and the other 2 patients had minimal residual tumor. The mean estimated blood loss during the resections was 556 ml (range 200-850 ml). The mean postoperative hematocrit level change was -17.3%. Two patients required blood transfusions. One patient, who underwent extensive tumor penetration with Onyx, developed a temporary partial cranial nerve VII palsy that resolved to House-Brackmann Grade I (out of VI) at the 6-month follow-up. One patient experienced improvement in existing facial nerve weakness after embolization. CONCLUSIONS Scepter catheter-based Onyx embolization seems to be safe and effective. It was associated with excellent distal tumor vasculature penetration and holds promise as an adjunct to conventional transarterial Onyx embolization of paragangliomas. However, the ease of tumor penetration should encourage caution in practitioners who may be able to effect comparable improvement in blood loss with more conservative proximal Onyx penetration.