Traumatic pseudoaneurysms of the head and neck: Early endovascular intervention
Article Outline
Background
Trauma to the head and neck with military munitions often presents with complex multisystem injury patterns. Vascular evaluation typically focuses on the carotid and vertebral arteries; however, trauma to branches of the external carotid artery may also result in devastating complications. Pseudoaneurysms are the most frequent finding on delayed evaluation and can result in life-threatening episodes of rebleeding.
Methods
Patients evacuated from the Afghanistan and Iraq conflicts with penetrating injury to the face and neck were evaluated by the vascular surgery service to determine the potential for unsuspected vascular injury. Patients with significant penetrating injury underwent computed tomography angiography (CTA) as the initial evaluation and subsequent arteriography in cases where injuries were suspected or metallic fragments produced artifacts obscuring the vasculature. Data on all vascular evaluations were entered prospectively into a database and retrospectively reviewed.
Results
Between February 2003 and March 2007, 124 patients were evaluated for significant penetrating trauma to the head and neck. Thirteen pseudoaneurysms of the head and neck were found in 11 patients: two in the internal carotid artery, one of the vertebral artery, and 10 involving branches of the external carotid. Seven pseudoaneurysms were symptomatic, of which two presented with episodes of massive bleeding and airway compromise. Seven pseudoaneurysms were treated with coil embolization, 1 with Gelfoam (Upjohn, Kalamazoo, Mich) embolization, 2 with stent grafts, 2 with open repair, and 1 with observation alone. None of the patients undergoing embolization had complications; however, a stent graft of the internal carotid artery occluded early, without stroke. All of the pseudoaneurysms had resolved on follow-up CTA or angiogram.
Conclusions
Pseudoaneurysms are a common finding in patients with high-velocity gunshot wounds or blast injuries to the head and neck. Most involve branches of the external carotid artery and can be treated by embolization. CTA should be performed on all patients with high-velocity gunshot wounds or in cases of blast trauma with fragmentation injuries of the head and neck.
High-explosive military munitions used on the battlefields of Iraq and Afghanistan have produced a variety of devastating injuries that are only rarely seen in civilian practice. In cases of penetrating trauma to the head and neck, the extent of injury often challenges the traditional protocols for evaluation that have developed in civilian settings. High-velocity rifles, improvised explosive devices (IEDs), rocket-propelled grenades, and mortars nearly always produce complex multisystem injuries that cross all three of the traditional zones of the neck. As seen in Fig 1, the number of projectiles can be in the hundreds or thousands, and virtually any vascular structure from the top of the skull to the sternal notch can be involved. Although these soldiers typically receive treatment of obvious vascular injuries within a few hours at local field hospitals, definitive evaluation and treatment is usually delayed for 48 to 72 hours until they can be evacuated to the United States.
Fig 1.
Patients with blast injury may have hundreds of small projectiles imbedded throughout the face and neck, across all three of the traditional zones.
When casualties arrive in Washington, DC, the vascular surgery service is faced with the challenge of identifying and treating any occult vessel injuries that may not have been diagnosed at the local field hospital. We are in the somewhat unusual position of performing a definitive evaluation of severely injured polytrauma patients several days after the initial injury. Missed injuries to the vasculature of the face and neck may have devastating consequences, and we have aggressively evaluated returning soldiers who have sustained penetrating trauma to the neck by using both conventional angiography and computed tomography angiography (CTA). This protocol was described in a previous publication.1
As we gained experience with these complex wounds, we were surprised to find that the most common undiagnosed vascular injuries were pseudoaneurysms of the extracranial vasculature. Although we also expected to find arteriovenous fistulas and unsuspected carotid occlusions, these problems were rare, and only a single case of each was encountered. These pseudoaneurysms have been sporadically reported in the civilian trauma literature and initially represented something of a management quandary for our surgeons.
Repair or ligation of pseudoaneurysms with traditional surgical techniques may be feasible in some cases. However, an open approach to many of these lesions may be fraught with peril due to grossly distorted and edematous tissue planes that often have heavy bacterial colonization. Simple observation was a poor option because these injuries could produce swelling and hemorrhage at unpredictable times, representing an acute danger to the upper airway. In most cases, endovascular techniques offered the most straightforward and low-risk treatment option. Embolization of external carotid lesions, in particular, was a simple and effective procedure that eliminated the risk of delayed bleeding and fatal airway compromise.
Methods
All patients evacuated from the Afghanistan and Iraqi theaters that underwent evaluation by the vascular surgery service for penetrating trauma to the face or neck between January 2003 and March 2007 were included in the study. This encompassed patients admitted to military hospitals within the national capital area, as well as local nationals who received definitive care by the primary author (M. C.) at an in-country Air Force Theater Hospital (AFTH) with advanced imaging capability to include CTA and digital subtraction angiography. Obviously life-threatening injuries such as expanding hematoma, active bleeding, and carotid injury with neurologic deficit were addressed in-theater before evacuation to the United States.
Patients judged to have significant penetrating injury to the face or neck by the admitting trauma surgeon at the time of admission were evaluated by the vascular surgery service. Injuries prompting consultation typically included any high-velocity gunshot wound (GSW) to the face or neck, blast injury with multiple metallic fragments in the soft tissue of the neck, a history of neck exploration performed in-theater, or a history of vascular injury that may or may not have been repaired in-theater. These patients immediately underwent CTA as their initial imaging study; however, CTA was occasionally nondiagnostic due to a large number of metallic fragments producing excessive artifact. Patients with nondiagnostic CTA or positive findings on CTA proceeded to digital subtraction angiography.
Between January 2003 and March 2006, CTA was performed on a 16-slice CT scanner (General Electric [GE] Healthcare, Milwaukee, Wis), which was upgraded to a 64-slice machine (GE Lightspeed VCT) in April 2006. CTA reconstructions were performed using the software package Volume Viewer 2 with Advanced Vessel Analysis (GE). The AFTH had a 2-slice machine (GE) during the study period.
Patients with vascular abnormalities on CTA underwent digital subtraction angiography to include selective views of the external carotid, internal carotid, or vertebral arteries as needed according to the CTA findings. If pseudoaneurysms were found and endovascular therapy was indicated, they were treated at the time of the initial diagnostic angiogram. Individuals with pseudoaneurysms that were palpable beneath the skin underwent duplex ultrasonography as the confirmatory study in addition to CTA.
Treatment management decisions were made by the individual attending vascular surgeons, all of whom were trained to perform advanced endovascular interventions, including stent grafting and microcatheter embolization. Patients undergoing endovascular interventions for pseudoaneurysm were studied after the procedure with CTA or repeat angiography to verify resolution of the pseudoaneurysm. Soldiers with penetrating injury isolated mainly to the brain or who were found to have intracranial vascular abnormalities on CTA were treated by the neurosurgery service and were not included in this study.
Data on type of injury, diagnostic evaluation, associated injuries, treatments, and outcomes were collected prospectively in an institutional trauma database that was retrospectively reviewed. Individuals with pseudoaneurysms of extracranial vessels were identified and are the basis of this report. A radiologist specializing in CTA (I. F.) reviewed all imaging studies to confirm the diagnosis and location of the pseudoaneurysms.
Results
During the study period, 124 patients were evaluated for significant penetrating trauma that potentially involved the vasculature of the face or neck, or both, and 13 pseudoaneurysms in 11 patients were identified from this cohort for an incidence of 9%. The Table summarizes the relevant information for each of these patients. Nine of the pseudoaneurysms resulted from blast injuries and four from GSWs. Only three of the patients had major neurologic deficits on presentation, with one hemispheric stroke, one penetrating brain injury, and one C5 spinal cord injury with quadriplegia.
Table. Summary of the 11 patients in whom 13 pseudoaneurysms of the head and neck were identified
| Patient | Mechanism | Involved artery | CTA result | Aneurysm diameter (mm) | Symptoms | Treatment | Outcome |
|---|---|---|---|---|---|---|---|
| 1 | GSW | Lingual | Positive | 11 | None | Coil embolization | Thrombosis |
| 2 | Blast | External carotid | Positive | 9 | None | Coil embolization | Thrombosis |
| 3 | Blast | Carotid bulb | Positive | 4 | None | Patch angioplasty | Uncomplicated repair |
| 4 | Blast | Superficial temporal | N/A | 10 | Pulsatile scalp mass | Ligation | Successful occlusion |
| 5 | Blast | Right distal maxillary | Positive | 10 | Massive bleed/airway compromise | Coil embolization | Thrombosis |
| Left distal maxillary | Positive | 15 | Minor bleed | Coil embolization | Thrombosis | ||
| 6 | GSW | External carotid | N/A | 12 | Massive bleed/airway compromise | Coil embolization | Thrombosis |
| 7 | GSW | Distal lingual | N/A | 3 | None | Observation | Spontaneously resolved |
| 8 | Blast | Facial | Positive | 15 | Sudden-onset neck swelling | Coil embolization | Thrombosis |
| 9 | GSW | Vertebral | Positive | 8 | None | Stent graft | Aneurysm thrombosed with patent vessel |
| 10 | Blast | Maxillary | Positive | 6 | None | Coil embolization | Thrombosis |
| Distal facial | Nondiagnostic | 17 | Pulsatile facial mass | Gelfoam⁎ embolization | Thrombosis | ||
| 11 | Blast | Internal carotid | Nondiagnostic | 5 | Stroke with negative neck exploration | Stent graft | Stent graft occlusion without stroke |
⁎Upjohn, Kalamazoo, Michigan. |
An initial CTA demonstrated the pseudoaneurysm in eight of 10 instances, whereas two aneurysms (patients 10 and 11) were obscured by artifact from fragments or dental implants. Overall sensitivity of CTA alone was thus 80%. No false-positive findings were reported from the CTAs. Three of the patients did not have an initial CTA due to various extenuating circumstances. One patient presented with an episode of massive bleeding into the oropharynx that needed to be immediately addressed in the operating room (patient 6, Fig 2). A second patient was judged to have a large burden of metallic fragments that would preclude adequate CT imaging, and a third presented late with a palpable pseudoaneurysm that was imaged by duplex ultrasound alone because a previous noncontrast CT showed that no fragments had penetrated deep to the platysma.
Fig 2.
A patient with a recent gunshot wound to the face presented with massive hemorrhage from the mouth. He was intubated and taken urgently to the operating room for coil embolization.
Seven pseudoaneurysms were symptomatic, with presentations ranging from an annoying pulsatile scalp mass to life-threatening hemorrhage, and six were incidental findings on CT scan or angiogram. One initially asymptomatic patient with a pseudoaneurysm seen on CTA had a massive multiunit hemorrhage into the upper airway and subsequent near-arrest while on the ward awaiting treatment. He survived after prompt airway control and immediate transfer to the operating room for catheter-directed embolization of the pseudoaneurysm.
There were two pseudoaneurysms of the internal carotid artery (ICA), one of the vertebral artery, and 10 arising from the external carotid or its branches. Aneurysms related to the external carotid branches were treated with coil embolization in 7 of 10 cases. One pseudoaneurysm, which was palpable directly beneath the skin on the upper lip, was accessed by direct percutaneous puncture and embolized with a small amount of Gelfoam (Upjohn, Kalamazoo, Mich) slurry. A second palpable aneurysm related to the superficial temporal artery was directly ligated by cutdown under local anesthetic. One very small pseudoaneurysm in a distal branch of the lingual artery was simply observed and had occluded on a repeat angiogram.
We found only one pseudoaneurysm of the ICA that was easily approached surgically, and this was repaired through an open approach with vein patch angioplasty. A symptomatic pseudoaneurysm of the distal extracranial ICA and an enlarging pseudoaneurysm of the vertebral artery were treated with stent grafts. In the case of the vertebral artery pseudoaneurysm, the injury at the level of C5 was treated with a 5- × 22-mm balloon-expandable iCAST stent graft (Atrium Medical, Hudson, NH). The injury to the distal ICA was addressed with a 6- × 30-mm self-expanding Wallgraft (Boston Scientific, Natick, Mass). Both patients who received stent grafts began therapy with aspirin and Plavix (Sanofi-Aventis, Bridgewater, NJ) postoperatively.
None of the patients sustained complications related to treatment of their pseudoaneurysms. No puncture-site complications, transient ischemic attacks, or strokes resulted from the endovascular treatments. The one ICA stent graft occluded early; however, anticoagulation was begun immediately, and the patient’s neurologic status remained completely unchanged. No patient had recurrent bleeding from a treated pseudoaneurysm, although one patient did have a minor bleeding episode from an undiagnosed second pseudoaneurysm. This additional lesion was imaged on a repeat CTA and subsequently treated by coil embolization. Follow-up CTA or conventional angiogram was obtained before discharge on 9 of 11 patients, and all demonstrated obliteration of the treated aneurysms.
Discussion
Although the literature is replete with isolated case reports of traumatic pseudoaneurysms of the head and neck,2, 3, 4, 5 the only available case series typically lump them together with all other types of traumatic vascular injury.6, 7, 8 In the military setting, we have found pseudoaneurysms of the head and neck to be the most common vascular injury discovered on delayed evaluation and believe they are worth considering as a separate entity.
We diagnosed these aneurysms in 9% of patients evaluated by the vascular surgery service for significant penetrating injury to the face and neck. Presumably, this relatively high incidence is a result of the uniquely destructive munitions used on the battlefield, which produce high-energy projectiles and result in extensive soft tissue destruction. Particularly in the case of IEDs, there may be hundreds or thousands of separate fragmentation wounds across all zones of the neck, each representing the potential for vascular injury. And even with GSWs, high-velocity rifle rounds produce extensive tissue destruction by cavitation and the fragmentation of bony structures of the face. This relatively high incidence may also reflect a referral bias to our service for patients with more extensive tissue damage or suspicion of vascular injury. On occasion, the injuries of patients with isolated facial fractures or ophthalmologic issues were treated by the trauma or subspecialty service without vascular consultation.
We relied heavily on CTA for the evaluation of these injuries, but it cannot necessarily be considered the definitive evaluation, and the workup should be tailored to the individual circumstances. As documented in our series, CTA was only 80% sensitive in the detection of pseudoaneurysms. This low sensitivity was mainly due to artifacts produced by metallic fragments within the neck, and patients with nondiagnostic CT scans still require conventional angiography.
It is also important to note that two patients who presented with palpable aneurysms beneath the skin of the face were imaged well with duplex ultrasonography. One of these aneurysms was not seen on CTA because of artifact from dental implants, and conventional angiogram also failed to demonstrate the aneurysm, presumably because of its very distal location in a tiny maxillary artery branch that did not fill well with contrast.
The phenomenon of palpable pseudoaneurysms related to the superficial temporal artery has been well described in the otolaryngology literature,9 although there are no reports of subcutaneous aneurysms elsewhere in the face. Physical examination and duplex ultrasound imaging are probably adequate to guide treatment of these small pseudoaneurysms of the face that are clearly isolated to the subcutaneous tissue and have no deeper injuries found on CTA.
Despite the observed limitations of CTA, we will continue to use it as the initial screening study, supplementing with conventional angiography or duplex ultrasound depending on the clinical situation. Familiarity with all three modalities is important because in many situations they complement each other, and no single imaging technique should be thought of as stand-alone. Although CTA had only 80% sensitivity, the only real limitation is artifact from large metallic fragments in the neck, and patients with excessive artifact can be selected for digital subtraction arteriography. In some instances, the CTA was actually superior to digital subtraction arteriography. As noted in Fig 3, some aneurysms are imaged quite well by CTA but are seen very poorly on a typical carotid arteriogram. In the case of this patient, selective injection of the lingual artery was necessary to fully visualize the pseudoaneurysm. In such instances where the initial CTA is diagnostic, it is usually possible to identify the relevant artery and target that vessel specifically on the subsequent angiogram. Reliance on CTA as the initial study also limits the number of negative arteriograms with their potential for puncture site complications and procedure-related stroke.
Fig 3.
A, This lingual artery pseudoaneurysm (arrow) was easily found on computed tomography angiography, but (B) was not imaged by the initial carotid angiogram. C, Selection of the lingual artery was necessary to adequately demonstrate the pathology.
CTA is likely to become even more useful as the technology improves, and anecdotally, we have noticed a decrease in the number of nondiagnostic scans since switching to the 64-slice scanner with its improved resolution. Optimally, a dedicated radiologist or vascular surgeon with extensive experience in CTA should perform the reconstructions because scanning technique and postprocessing can often markedly reduce the artifact from metallic fragments and result in much cleaner studies. The number of strictly diagnostic angiograms of the head and neck performed by the vascular surgery service has dropped off sharply since the acquisition of the new 64-slice scanner.
When we initially began encountering these pseudoaneurysms, the appropriate treatment modality was not obvious. Their natural history is not well documented, and an initial period of observation in these patients with multisystem injuries did not seem unreasonable. Published reports demonstrate that many iatrogenic pseudoaneurysms will close spontaneously, and at least one report suggested that most incidentally found vascular injuries are of no consequence.10, 11 We found, however, that many of these patients required operative fixation of jaw and maxillary fractures, and the otolaryngology or oral-maxillofacial surgery services were reluctant to manipulate bone fragments for fear of causing uncontrollable bleeding.12 After encountering two episodes of massive hemorrhage from these pseudoaneurysms, we altered our treatment protocols to address the pseudoaneurysms as quickly as possible. Most of these patients had associated injuries requiring surgical procedures, and it seems prudent to embolize or place stent grafts in these aneurysms before any manipulation of the face or neck.
Although these aneurysms occasionally may be surgically accessible, they are more typically located deep within heavily traumatized structures of the face or neck. An endoluminal approach is appealing, since cannulation of even fourth or fifth order external carotid branches in young, healthy, nonatherosclerotic trauma patients is usually straightforward. In these delayed evaluations where there is not ongoing blood loss and relative hemodynamic stability, virtually all patients may be considered for endovascular therapy. Endoluminal control can often be achieved quickly even in cases with active bleeding, as in patient 6, eliminating the need for rapid dissection through a bloody field.
In the case of more superficial pseudoaneurysms, authors have reported coil embolization, open ligation, and direct thrombin injection.9, 13, 14 An endoluminal approach with coils for these injuries seemed excessive, and simple cutdown with ligation was straightforward and easily accomplished. Direct puncture of the aneurysm with a 19- gauge needle and embolization with Gelfoam slurry was even easier and saved one of our patients an incision on a cosmetically important area of the face. We did not use duplex-guided thrombin injection, although this may also be a reasonable option.
With instances of injury to the common carotid or proximal ICA, we still recommend an open repair in the case of a typical young trauma patient with a surgically favorable neck. The distal internal carotid and vertebral arteries, however, can be treated effectively with endovascular approaches.15, 16 Fig 4 demonstrates a vertebral artery pseudoaneurysm that was excluded using a stent graft. This patient’s vertebral artery was large (5 mm) and was addressed with a balloon-expandable stent graft that was delivered through a 6F percutaneous femoral access. Although coil occlusion of the vertebral artery would certainly be an option as well, stent grafting accomplished the same result with maintained patency.
Fig 4.
A, A vertebral artery pseudoaneurysm before and (B) after being treated by stent grafting.
Conclusion
Military munitions currently used in the conflicts of the global War on Terror can produce devastating trauma to the face and neck, which is often associated with the formation of pseudoaneurysms. CTA will often yield the correct diagnosis, but it should be supplemented by conventional angiography or duplex ultrasound imaging when necessary. These pseudoaneurysms often become symptomatic and may produce rapid, life-threatening hemorrhage. Given their unpredictable risk of bleeding, pseudoaneurysms should be treated expeditiously in most cases, and most can be repaired with minimally invasive endovascular techniques that are safe and effective.
Author contributions
References
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Competition of interest: none.
PII: S0741-5214(07)01349-3
doi:10.1016/j.jvs.2007.08.021
© 2007 The Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.
