Radiol Oncol 2020; 54(3): 253-262. doi: 10.2478/raon-2020-0035 253 review Transarterial embolization of the external carotid artery in the treatment of life- threatening haemorrhage following blunt maxillofacial trauma Crt Langel1, Dimitrij Lovric1, Ursa Zabret1, Tomislav Mirkovic2, Primoz Gradisek2, Anita Mrvar-Brecko2, Katarina Surlan Popovic1 1 Institute of Radiology, University Medical Centre Ljubljana, Ljubljana, Slovenia 2 Department of Anaesthesiology and Surgical Intensive Care, Division of Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia Radiol Oncol 2020; 54(3): 253-262. Received 7 February 2020 Accepted 22 April 2020 Correspondence to: Assoc. Prof. Katarina Šurlan Popović, M.D., Ph.D., Clinical Institute of Radiology, University Medical Centre Ljubljana, Zaloška c 7, 1000 Ljubljana, Slovenia. E-mail: katarina.surlan-popovic@mf.uni-lj.si. Disclosure: No potential conflicts of interest were disclosed. Background. Severe bleeding after blunt maxillofacial trauma is a rare but life-threatening event. Non-responders to conventional treatment options with surgically inaccessible bleeding points can be treated by transarterial emboliza- tion (TAE) of the external carotid artery (ECA) or its branches. Case series on such embolizations are small; considering the relatively high incidence of maxillofacial trauma, the ECA TAE procedure has been hypothesized either underused or underreported. In addition, the literature on the ECA TAE using novel non-adhesive liquid embolization agents is remarkably scarce. Patients and methods. PubMed review was performed to identify the ECA TAE literature in the context of blunt maxillofacial trauma. If available, the location of the ECA injury, the location of embolization, the chosen embolization agent, and efficacy and safety of the TAE were noted for each case. Survival prognostic factors were also reviewed. Additionally, we present an illustrative TAE case using a precipitating hydrophobic injectable liquid (PHIL) to safely and effectively control a massive bleeding originating bilaterally in the ECA territories. Results and conclusions. Based on a review of 205 cases, the efficacy of TAE was 79.4–100%, while the rate of ma- jor complications was about 2–4%. Successful TAE haemostasis, Glasgow Coma Scale score ≥ 8 at presentation, injury severity score ≤ 32, shock index ≤ 1.1 before TAE and ≤ 0.8 after TAE were significantly correlated with higher survival rate. PHIL allowed for fast yet punctilious application, thus saving invaluable time in life-threatening situations while si- multaneously diminishing the possibility of inadvertent injection into the ECA-internal carotid artery (ICA) anastomoses. Key words: blunt maxillofacial trauma; external carotid artery injury; intractable bleeding; non-adhesive liquid embo- lization agent; precipitating hydrophobic injectable liquid, neurointervention Introduction Maxillofacial trauma comprises roughly 10% of all trauma cases.1 It is associated with a wide range of problems, including airway compromise, cervi- cal spine injuries and bleeding.2 Life-threatening haemorrhage secondary to blunt maxillofacial trauma is considered rare, occurring in 1.2%–4.5% of trauma-related maxillofacial fracture cases.2-5 The most common origins of haemorrhage in max- illofacial trauma are the internal maxillary artery (IMA), the IMA’s distal branches, and the main trunk of the external carotid artery (ECA).6 A diverse range of imaging manifestations can present in the setting of blunt carotid artery trau- ma, including various dissection subtypes (mini- Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma254 mal intimal injury, raised intimal flap, dissection with an intramural hematoma, occlusion), pseu- doaneurysm, transection with an active haemor- rhage, and arteriovenous fistula.7,8 In treating severe maxillofacial injuries, airway, breathing and circulation management precede all other procedures. Special care is aimed towards the protection of the airway as the tongue and the soft tissues of the lower face can move backward and obstruct the pharynx due to the decreased level of consciousness, bilateral mandibular fractures, soft tissue swelling and expanding hematomas.2 Further treatment includes manual compression, nasal packing, coagulopathy correction, cauteriza- tion, reduction of the fractures and local vascular control to stop the bleeding from the intra-osseous branches near the fracture lines.9 Open surgical li- gation or transarterial embolization (TAE) of the ECA are available as the most definite options. Advantages of TAE over ligation include rapid access, not necessarily requiring general anaes- thesia, superior haemorrhage origin localization using angiography, the ability to control multiple local bleeding points, the ability to perform super- selective therapeutic vessel occlusion by cannulat- ing the smaller vessel branches not amenable to open surgical repair, and short procedure time.10 In addition, ECA ligation oftentimes requires repeat ligation or subsequent TAE to effectively stop the bleeding, whereas TAE is usually efficacious in a single session.2,11 Furthermore, TAE offers the op- tion to embolize the bleeding origins of a possible concomitant abdominal or other internal haemor- rhage in the same session.12 In certain guidelines, surgical ECA ligation has been completely re- placed by TAE for maxillofacial bleeding control.2 The initial search data for the review part of this manuscript was processed following a simpli- fied variant of the Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA) guidelines showing the number of cases identified, included and excluded, plus the reasons for exclu- sions (Figure 1).13 The included cases were then ana- lysed in order to obtain the data regarding the use of embolization agents, and the efficacy and safety of the TAE procedure in the context of blunt maxillofa- cial trauma with bleeding originating from the ECA. Transarterial embolization of the ECA Embolization therapy aims at controlling an active bleeding by occluding the feeding artery with an embolization agent (EA).14 The TAE technique was first suggested by Brooks et al. in the 1930s. In the early 1970s, Rosch and Dotter used it for the first time to treat a traumatic vascular injury.15 It also became an accepted treatment option for a variety of vascular lesions unrelated to trauma, including arteriovenous malformations, glomus tumours, juvenile angiofibromas, and intracranial meningi- omas.16 A pioneer case describing a successful IMA TAE in the treatment of intractable epistaxis was reported by Sokoloff et al. in 1974.17 Decades of innovation brought about major ad- vances in embolization materials, however, to this day, the principles of the TAE procedure remain largely unaltered.18 Initially, a vascular access is established by a standard transfemoral approach using the Seldinger technique.19 Alternatively, bra- chial or axillary arterial access might be required in case of severe bilateral lower extremity injury.20 Diagnostic angiography of the whole circulation at risk is then performed, including bilateral common carotid arteries (CCAs), internal carotid arteries (ICAs), vertebral arteries (VAs), and ECAs. If the FIGURE 1. A flow diagram based on simplified Preferred Reporting Items for Systematic Reviews and MetaAnalyses (PRISMA) guidelines depicting the number of cases identified, included and excluded. The reasons for the exclusions are also noted.13 Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma 255 preliminary computed tomography angiography (CTA) or clinical findings suggest an injury to a spe- cific smaller vessel, e.g. the IMA, the lingual artery or the superficial temporal artery, further micro- catheter angiography of these territories is carried out. The purpose is to obtain a general overview of the complete vasculature and to exclude a possible concomitant injury to the CCA, ICA or VA.21 The vessel that is the source of an active haemorrhage is then therapeutically occluded. The aim of the embolization is to stop the active bleeding, prevent any subsequent rebleeding events, and preserve as much perfusion to the nearby structures as possi- ble, thereby reducing the chance of unnecessary tis- sue damage. This means embolization is attempted as close to the lesion as possible to avoid occluding the vessels branching off proximally to the embo- lization site. Circumstances permitting, the culprit vessel should ideally be embolized both distally and proximally to the lesion in order to prevent rebleeding via the collateral circulation.21 The de- livery of the EA is performed under fluoroscopic visualization to the point of contrast medium stasis within the embolized vessel. Embolization agents Depending on the vessel calibre, type of vessel in- jury and other factors, a variety of EAs with dif- fering inherent properties and behaviour may be used. Historically, the first EA was autologous tissue (including blood clots, subcutaneous tissue and muscle) followed by silk threads.22 Their use gradually declined with the advances in newer EAs, imaging and (micro)catheter technologies.14,23 Data gathered in Table 1 indicates coils and gel- atine foam (Gelfoam) are the EAs most frequently used for TAE in the context of blunt maxillofacial trauma. There have also been numerous instanc- es of polyvinyl alcohol (PVA), microspheres, and N-butyl-2 cyanoacrylate (NBCA) use. One case of silastic spheres, two cases of Onyx, and a single case of precipitating hydrophobic injectable liquid (PHIL) use have been reported. Coils are made from platinum or steel, measure 0.2–1.3 mm in diameter and can be supplied in a variety of lengths, shapes and levels of stiffness. They may be bare or fibered with materials such as wool, silk, nylon fibres, polyester, Dacron or PVA.18 Coils embolize a vessel by physically slowing down the local blood flow, by providing a thrombogenic locus, and by damaging the vessel wall, thus induc- ing the release of thrombogenic factors. Time to oc- clusion is typically 5 minutes or less after coil inser- tion, depending on the type of coil used, the rate of blood flow through the target vessel and the blood’s coagulation properties.18 Larger diameter platinum coils offer good radiopacity, while smaller diameter coils (microcoils) provide for more targeted distal deployment. The possible complications of TAE us- ing coils are non-target vessel occlusion, vessel in- jury, coil migration, and infection.18,24 Coils prohibit any future endovascular access distal to the occlu- sion point, which is particularly relevant in rebleed- ing events following collateralization.21 Gelatine foam (Gelfoam) (Pfizer, Kalamazoo, MI, USA) is a porous material with haemostatic properties prepared from purified porcine skin gelatine. It usually supplied as a block of sponge that needs to be cut into smaller cube- or torpedo- shaped particles prior to embolization. Gelfoam induces foreign body reaction and necrotizing ar- teritis, resulting in the formation of a thrombus.25 Gelfoam as a standalone EA provides a temporary vessel occlusion; recanalization typically occurs within 3 weeks to 3 months, but the exact time and the extent cannot reliably be predicted.23 A com- bined coils-Gelfoam embolization may be particu- larly well suited for coagulopathic patients as such vessel occlusion is precise, fast, and permanent.23 The most significant disadvantage of Gelfoam-only embolization is the reliance on manual prepara- tion of the particles, limiting the reproducibility and predictability of the exact embolization site. Furthermore, air bubbles typically form in the Gelfoam-contrast mixture, presenting a potential risk for an aerobic infection.18 Polyvinyl alcohol (PVA) particles (Boston Scientific, Cork, Ireland; Cordis J&J Endovascular, Miami, FL, USA) are irregularly-shaped permanent embolic agents ranging from 100 to 1100 μm in size. The PVA’s mechanism of action includes adherence to the vessel wall, induction of an inflammatory re- action, focal angionecrosis and the resulting vessel fibrosis. There is a considerable variability in parti- cle size because fragments smaller than the stated size range are allowed to enter the particulate mix- ture during production. This in turn increases the risk of distal, non-target embolization as particles tend to lodge in the smallest vessel they can fit in. On the other hand, the PVA particles are also prone to aggregation; this can lead to more proximal ves- sel occlusion than expected based on the stated size range of the particles.18 Microspheres (Embosphere and EmboGold, Merit Medical Systems, South Jordan, UT, USA; Contour SE, Boston Scientific, Natick, MA, USA; Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma256 TABLE 1. Data from studies, case series and case reports pertaining to TAE of the ECA or its branches in the treatment of haemorrhage caused by blunt maxillofacial trauma First author Year Pub- lished Case number Vessel injured Vessel embolized Emboli- zation agents used efficacy (complete cessation of bleeding following TAE of the ECA or its branches) complications Bynoe2 2003 1 none identified RL ECA C GF PVA 100% partial tongue necrosis 2 R IMA R IMA none 3 R IMA RL IMA none 4 none identified RL ECA above LA none 5 none identified RL ECA above LA groin hematoma 6 none identified RL ECA above LA none 7 L IMA L IMA none 8 L IMA L IMA groin hematoma 9 L IMA R ECA above LA, L IMA none 10 none identified R ECA above LA none Chen12 2009 11 R IMA, R STA not specified CGF 100% could not be assessed 12 R IMA not specified CGF none 13 L IMA not specified GF could not be assessed 14 R IMA not specified GF none 15 L IMA not specified GF none 16 RL IMA not specified GF could not be assessed 17 L ECA not specified CGF none 18 L IMA not specified GF none Cogbill48 2008 19–39 not discernible due to the merging of blunt and penetrating trauma patients' data not discernible due to the merging of blunt and penetrating trauma patients' data C GF 85% none Kim49 2011 40 not specified L IMA PVA success none Komiyama50 1998 41 not specified R SPA C GF PVA 100% none 42 not specified RL SPA, IOA, FA none 43 not specified L SPA none 44 not specified RL SPA, LPA, ADTA 6, IAA7, FA, LA none 45 not specified RL SPA, FA none 46 not specified BL SPA, AAA8 could not be assessed 47 not specified R STA, FA none 48 not specified RL GPA9, EA none 49 not specified RL SPA, SPAA10 none Kuan47 2015 50–76 12 x IMA not specified C GF PVA NBCA 92.3%; data includes one penetrating injury no serious systemic or neurologic complications 6 x FA 6 x LA 5 x MMA11 3 x ECA 1 x APA12 5x other vessels Note: this statistics also includes one penetrating trauma. Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma 257 First author Year Pub- lished Case number Vessel injured Vessel embolized Emboli- zation agents used efficacy (complete cessation of bleeding following TAE of the ECA or its branches) complications Langel 2020 77 L IMA + R SPA L ECA + R SPA CPHIL 25 success none Liao40 2007 78–112 25 x IMA not specified not specified 79.4% none reported 5 x MMA 4 x ECA 4 x SPA 4 x STA 2 x APA 1 x FA 1 x SALA 1 x IALA 1 x DPA 5 x other (observed contrast pooling) Liu3 2008 113 L STA + L IMA not specified GF success none reported Maiorello51 2011 114 L FA L FA Onyx 18 success none Mauldin52 1989 115 R ECA R ECA C success none reported Mehringer52 1982 116–194 not discernible due to the merging of blunt and penetrating trauma patients' data not discernible due to the merging of blunt and penetrating trauma patients' data GF PVA silastic spheres 100% 1x cerebral infarction 2x transient occulomotor nerve palsy Mehrotra6 1984 195–196 R IMA R IMA GFPVA success none reported L IMA L IMA GF success none reported Noy38 2007 197 L IMA, RL FA L IMA, RL FA MSNBCA success none Remonda54 2000 198 RL IMA not specified C PVA NBCA success Transient trismus Thiex33 2011 199 L FA not specified Onyx success none Wang55 2015 200 L STA not specified C 100% none 201 L FA not specified C none 202 R STA not specified C none 203 R STA not specified C none 204 L STA not specified C none Wong56 2013 205 R IMA R IMA NBCA success none Anatomical abbreviations: AAA = anterior auricular artery; ADTA = anterior deep temporal artery; APA = ascending pharyngeal artery; DPA = descending palatine artery; ECA = external carotid artery; FA = facial artery; GPA = greater palatine artery; IAA = inferior alveolar artery; IALA = inferior alveolar artery; IMA = internal maxillary artery; IOA = infraorbital artery; L = left; LPA = lesser palatine artery; MMA = middle meningeal artery; R = right; SALA = superior alveolar artery; SPA = sphenopalatine artery; SPAA = superior posterior alveolar artery; STA = superficial temporal artery Embolization agent abbreviations: C = coils; GF = Gelfoam; MS = microspheres; PHIL = precipitating hydrophobic injectable liquid; PVA = polyvinyl alcohol particles Embozene, Celenova, San Antonio, TX, USA; Quadrasphere, Merit Medical Systems, South Jordan, UT, USA; Bead Block and LC Bead, Biocompatibles, Farnham, UK) are smooth globu- lar structures made from an acrylic polymer matrix impregnated with porcine gelatine. They are hy- drophilic, non-resorbable, non-aggregating, non- fragmenting spheres sized 40 - 1200 μm. Sizing inside a particular stated size range follows the Gaussian distribution and is thus more predictable Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma258 than is the case with PVA particles. After lodging in vessels, microspheres induce a histological reaction similar to PVA particles. The most notable down- side of using microspheres is the necessity to in- termittently agitate the particle-saline suspension prior to application in order to prevent sedimenta- tion.18,25,26 Also of note is the fact that microspheres of different manufacturers vary in elasticity and, as a consequence, particles of identical size range but different composition occlude vessels at different levels of the vascular tree.25,27 NBCA (TruFill, Cordis, Miami Lakes, FL; Histoacryl, B. Braun Aesculap, Tokyo, Japan; Glubran 2, Gem, Viareggio, Lucca, Italy) is a syn- thetic adhesive liquid EA (glue) that is accompa- nied by a separately packed tantalum powder, act- ing as a radiographic opacifier, and ethiodized oil, functioning as a polimerization retardant. All three components are mixed just before deployment. Once the solution is exposed to anionic environ- ment such as blood, polymerization takes place at a rate dependent on the NBCA concentration. NBCA forms a permanent cast obstructing the vessel lu- men. This occurs independently of the endogenous coagulation system - an important characteristic when dealing with exsanguinating trauma cases.18 NBCA glue also induces vessel wall inflamma- tion reaction resulting in fibrosis. The downside of NBCA use is that the catheter may become glued to the vessel wall if not pulled back quickly enough following glue injection. Glue polymerisation can also occur both distally or proximally to the in- tended occlusion location. NBCA deployment thus requires a skilled operator.28 Silastic spheres are the oldest non-absorbable particulate EA, introduced in 1964, and have since been replaced by more modern EAs.29 Onyx (Medtronic, Dublin, Ireland) is an ethyl- ene vinyl alcohol (EVOH) copolymer-based non- adhesive liquid EA dissolved in dimethyl sulfox- ide (DMSO) with added radiopaque tantalum powder. It was introduced in 1990. As is the case with other DMSO-based non-adhesive liquid EAs, once injected, the DMSO component dissolves in- to the blood and the copolymer component starts gradually precipitating in a centripetal fashion. The non-adhesive nature allows for long injec- tion times and mid-injection control angiography, if needed. Onyx’s final solidification occurs in 5 minutes.30 There are several drawbacks to this EA, including long pre-injection preparation time (20 minutes of mixer shaking are required to achieve homogenization), a self-hiding effect when used in larger amounts due to high radiopacity, plenty of artefacts in a postinterventional imaging, and the potential to combust or produce sparks during monopolar surgical cauterization.31,32 In addition, Onyx’s dark colour may result in a black discol- oration of the skin after superficial embolization or subcutaneous extravasation of the EA.33,34 Precipitating hydrophobic injectable liquid (PHIL) (MicroVention, Tustin, CA, USA) is a non- EVOH copolymer-based non-adhesive liquid EA suspended in DMSO with iodine covalently bond- ed to copolymer to provide radiopacity. It was in- troduced in 2015. In comparison to Onyx, PHIL is supplied ready-to-use (no shaking is necessary), requires lower volume to achieve the same extent of embolization, is faster to fully precipitate (3 min- utes), does not suffer from the self-hiding effect, pro- duces fewer artefacts in postinterventional imaging, is not hazardous to surgical cauterization, and is not dark coloured which diminishes the possibility of skin discoloration.35,36 PHIL is also more homog- enous on fluoroscopy during prolonged injections, but less radiopaque than Onyx once injected.23 According to the literature, no cases of blunt trauma-related ECA-territory embolization using other modern non-adhesive liquid EAs, such as Squid (Emboflu, Gland, Switzerland), have so far been reported. In the future, other cutting-edge EAs, such as homogenous microparticles or biode- gradable drug-bearing microspheres produced by droplet microfluidics technology, are expected to see regular clinical use.37 Efficacy and safety Various studies and case reports have shown the ECA TAE to be a safe and efficacious method in maxillofacial blunt-trauma related haemorrhage control, although direct comparison of the re- viewed literature is rendered difficult by the vari- ations in reporting. Two studies authored by Noy et al. and by Hayes et al. investigating intractable maxillofacial bleeding of various aetiologies, in- cluding but not limited to trauma, enrolling 74 pa- tients in total, found TAE to be efficacious in 89.1 - 90.0%.38,39 A study by Liao et al. focusing exclu- sively on trauma-related oronasal bleeding enroll- ing 34 patients discovered TAE to be efficacious in 79.4%.40 The data collected in Table 1 show that the efficacy of TAE ECA ranges from 79.4% to 100%, with the largest series attaining the perfect success rate comprising 10 cases. These results are similar to the efficacy of non-trauma-related TAE proce- dures involving the ECA (80%–97%).41-43 Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma 259 The complications among the 205 cases re- viewed in Table 1 include groin hematoma (2 cas- es), cerebral infarction (1 case), partial tongue ne- crosis (1 case), transient occulomotor nerve palsy (1 case), and transient trismus (1 case), indicating an overall complication rate of 3%. However, there is high variability in reporting styles regarding the complications. For example, certain authors lim- ited the reporting only to serious neurologic or systemic complications without further expound- ing on the exact criterion that delimited the serious complications from the minor ones. Furthermore, complications that could not be assessed might have occurred, e.g. due to patient dying or entering a vegetative state. In addition, it was not possible to determine the risk of publication bias or selective reporting. It is thus safe to assume the overall com- plication rate to be higher than directly indicated by Table 1 data. Duncan et al. found the rate of major complications (comprising cerebral vascular insult only) to be 2% but also reported a rate of mi- nor complications (comprising headache, transient facial pain, paraesthesia, and local groin complica- tions) of 25% in their series of 57 embolizations, of these 3 trauma-related.44 Cullen and Tami re- viewed the literature of 264 cases of IMA emboli- zations for the treatment of posterior epistaxis and found the rate of major complications (hemiplegia, facial nerve paralysis, cheek necrosis, ICA intimal injury, catheter stuck in a vessel, myocardial infarc- tion) to be 4%, and the rate of minor complications (IMA spasm, hypotension, hematoma, groin bleed, oedema, trismus, paraesthesia, persistent pain, skin slough, palate ulceration, aspiration pneumo- nia, hepatitis) to be 10%.45 The relatively low rate of major complications might be in part due to the rich collateral flow between the ipsilateral and contralateral ECA branches distal to the lingual artery that ensure ad- equate tissue perfusion in case of one-sided ECA embolization.46,2 Duncan et al. discovered that the complication rate tends to drop with the use of mi- crocatheter techniques. They have also observed a decrease in complication rate in the more recent studies that could be ascribed to factors such as im- provement in catheter and guidewire design and increased operator experience.44 Survival prognostic factors Liao et al. examined a series of 34 cases of crani- ofacial trauma requiring TAE and discovered that there was a significant contribution of successful TAE haemostasis to patient survival (p = 0.001). Glasgow Coma Scale score (GCS) ≥ 8 at presenta- tion, injury severity score (ISS) ≤ 32, and shock in- dex (SI; heart rate divided by systolic blood pres- sure) ≤ 1.1 before TAE and ≤ 0.8 after TAE were also significantly correlated with the patients’ higher survival rate (p < 0.05). The need to treat a second- ary abdominal bleeding origin by laparotomy sig- nificantly decreased the rate of survival (p = 0.023). The patients’ age, the need to perform craniotomy, the bilateral distribution of the bleeding vessels, and the number of the haemorrhaging vessels per patient were not correlated with the patient sur- vival (p > 0.05).40 Kuan et al. confirmed some of the findings by Liao et al. and further discovered that patients with initial haemoglobin level lower than 10 g/dL and patients with brain midline shift observed by com- puted tomography (CT) had statistically higher odds ratios predicting mortality than their coun- terparts as estimated by univariate logistic regres- sion.47 An illustrative case report A 20-year-old, previously healthy male was brought to the emergency department in 2019 after an acci- dental 20 m (65 ft), head-first fall to the ground. He had been cleaning windows of his 7th floor dorm room when he lost balance and fell. Eyewitnesses reported the patient had been lying on his stomach after impacting the ground but later managed to roll on his back by himself. A physician-led emer- gency medical service arrived on the scene in 10 minutes, finding the patient verbally responsive and making an effort to get up. Initial Glasgow Coma Scale (GCS) was an estimated 13. Severe fa- cial trauma compromising the airway and, within a few minutes, cessation of spontaneous respira- tion necessitated rapid sequence intubation which proved challenging with several failed attempts. Asystole was observed on ECG prompting resus- citation efforts that resulted in the return of spon- taneous circulation and sinus rhythm 20 minutes later. Upon arrival at a Level I trauma centre, the patient presented with GCS 5, blood pressure 70/40 mmHg, heart rate 100/min., a multifragment facial fracture (Figure 2A), a ruptured right eye, massive bleeding from the nose and the left ear, a fractured right 4th rib, a fractured left radius, a displaced left femoral fracture and a fractured left tibia. Adhering to our institution’s standard trauma pro- tocol, the possible abdominal and thoracic sources Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma260 of major blood loss were excluded. Astonishingly, US, XR, CT and CTA imaging indicated no signifi- cant damage to the neurocranium, parenchymal organs or major thoracic or abdominal vessels. Aorto-cervical CTA was then performed, reveal- ing contrast extravasation from the left IMA and the right sphenopalatine artery (SPA) (Figure 2B). This was consistent with the clinical presentation of severe antero-posterior epistaxis and pulsatile bleeding from the left ear. Nasal packing using bal- loon catheter inserted through the nares into the nasopharynx was performed by an ear, nose and throat (ENT) specialist to successfully control the nose bleeding. Tamponade of the left ear, however, proved to be inadequate with profound bleeding still persisting. Surgical treatment to control the haemorrhage by ligating the left ECA was decid- ed against due to lesion inaccessibility caused by extensive soft tissue damage and swelling. Blood pressure remained low (60/40 mmHg) despite hav- ing hitherto administered a total of 5 litres of flu- ids, including blood transfusion. Tranexamic acid and vasopressors were also applied, to little avail. In these life-threatening circumstances, TAE of the bleeding origins was considered the only remain- ing option. The patient was transferred to the neurointer- ventional suite and a standard right transfemoral vascular access was established. Digital substrac- tion angiography (DSA) showed a laceration of the left ECA with an ensuing 3 × 4 cm pseudoaneurysm continuing into the proximal part of the left IMA (Figure 3A). DSA also showed a right SPA lacera- tion with two small accompanying pseudoaneu- rysms (Figure 4A). The two culprit arteries were then superselectively catheterized and embolized. ECA embolization was performed using platinum coils and PHIL 25, while the SPA was embolized with PHIL 25 only (Figures 3B and 4B). In the case of the ECA embolization, coils created a mesh scaf- fold acting as a thrombogenic locus, and PHIL was then added to form a coagulopathy-independent lumen-obliterating cast. PHIL was chosen over other available liquid EAs for its ready-to-use char- acteristics, saving precious time in an emergency setting. In addition, its lava-like polymerisation properties ensured a well-controlled application, helping prevent any inadvertent injection into the dangerous ECA-internal carotid artery and ECA- vertebral artery anastomoses. Effort was made to embolize at or just proximal to the laceration point in order to preserve proxi- mal arterial territories. Embolization was contin- ued to the point of arterial stasis. Due to the well- FIGURE 2. (A) A 3D CT reconstruction showing multiple maxillo-facial fractures. (B) An aortocervical CTA showing two small hematomas in the region of the right pterygopalatine fossa and nasal cavity (black arrows) and a cm 3 × 4 cm hematoma in the region of the left masticatory space and deep parotid space (white arrows). Also visible is a hyperdense material used in left ear tamponade (empty arrows). A B FIGURE 3. (A) A lateral left ECA angiogram showing ECA laceration with 3 × 4 cm pseudoaneurysm continuing into the proximal part of the left IMA. Contrast extravasation can be observed in the vicinity of the pseudoaneurysm. (B) A fluoroscopic view showing left ECA embolization using coils (black arrow) and PHIL 25 liquid embolization agent (white arrow) under balloon flow control (empty arrow). Also of note area small number of stray coils anchored in the vessel in the region of PHIL application (white arrow). (C) A post-embolization lateral left ECA angiogram showing complete exclusion of the ECA distally to the facial artery (black arrow). A B C FIGURE 4. (A) A lateral right ECA angiogram showing two pseudoaneurysms in the region of the right pterygopalatine fossa and nasal cavity (black arrows). (B) Fluoroscopy showing microcatether proximally to the hematoma in the right pterygopalatine fossa (black arrow) prior to PHIL 25 application. Also visible is the embolized contralateral ECA (empty arrow). (C) A post-embolization right ECA angiogram showing complete sphenopalatine artery occlusion (black arrow). Also visible are the patent vessels proximally to the embolization. A B C Radiol Oncol 2020; 54(3): 253-262. Langel C et al. / Transarterial embolization of the external carotid artery and blunt maxillofacial trauma 261 developed left ECA and the resulting high blood flow to the pseudoaneurysm, the ECA emboliza- tion was performed under flow control provided by temporary proximal balloon occlusion. No flow control was needed for the SPA embolization. The embolizations of both lesions were immediately followed by complete cessation of the ear bleeding. Postembolization imaging showed total exclu- sion of the lacerated vessels (Figures 3C and 4C), complete patency of all proximal vessels, no collat- eral pathways to the pseudoaneurysm and no oth- er origins of bleeding. There were no procedure- related complications. To our knowledge, this case is the very first published report of PHIL 25 use for a safe and ef- ficacious management of a massive bleeding origi- nating in the ECA territory. Informed consent was obtained from the patient included in this case re- port as well as the consent for publication of the individual person’s data. Conclusions Severe bleeding secondary to blunt maxillofacial trauma is a rare but life-threatening occurrence. Conventional treatment options include manual compression, nasal packing, coagulopathy correc- tion, cauterization, fracture reduction and local vascular control. Open surgical ligation or TAE of the ECA are available as the most definite ap- proaches. Both are similarly efficacious and safe, but TAE offers many advantages, including short- er procedure time, more precise haemorrhage lo- calization, vessel occlusion superselectivity, and the ability to embolize a possible concomitant abdominal or other bleeding during the same ses- sion. Major complications of TAE are rare owing to rich collateral blood supply in the ECA territory, with the exception of the lingual artery. 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