The Journal for Vascular Ultrasound 34(3):139–142, 2010
Acquired Arteriovenous Fistula of the Temporal Artery and Vein: A Rare Finding Joanne Porter, RVT, RDMS; Bruce Brener, MD, RVT; Yolanda Vea, MD; Waseem El-Halabi, HBSC ABSTRACT An arteriovenous fistula is an abnormal communication that exists between an artery and a vein. There have been few cases of arteriovenous fistulae involving the superficial temporal artery reported and even fewer deemed to be nontraumatic in origin. This report describes a case of arteriovenous fistula of the superficial temporal artery that was diagnosed by duplex ultrasound complemented with color Doppler and confirmed by pathology. In addition to relating the details of the sonographic examination, the case study will examine the etiology, clinical manifestations, and treatment options for arteriovenous fistulae of the superficial temporal artery.
Introduction An arteriovenous fistula (AVF) is an abnormal connection between the high pressure arterial system and the low-pressure venous outflow system. These communications may be congenital (present at birth) or be acquired (usually from trauma). The more uncommon of the two, congenital AV fistulae, form during fetal development and are often small and do not require specialized care. Conversely, traumatic AVF are often symptomatic and necessitate surgical care.1 Arteries and veins lying in close proximity to one another are at increased risk for the formation of AVF. Two theories attempt to explain the mechanism behind fistula formation. The first, “laceration theory,” postulates that laceration of the vessels simultaneously creates concurrent damage that leads to both vessels being joined together during the healing process. The second, “disruption theory,” offers that endothelial buds from disrupted vasa vasorum grow into adjacent vessels, creating the fistula. A superficial temporal AVF forms between the superficial temporal artery and any vein lying immediately adjacent to it. There have been very few cases of AV fistulae of the superficial temporal artery reported in the literature to date and these lesions are considered to be extremely uncommon. Case Report A 55-year-old woman was seen for a vascular consultation with complaints of a 1-year history of a loud
From the Saint Barnabas Ambulatory Care Center, Livingston, NJ. Presented at the 2008 SVU Annual Conference in San Diego, CA. Address correspondence to: Joanne Porter, RVT, RDMS, Vascular Supervisor/Technical Director, Saint Barnabas Ambulatory Care Center, 200 South Orange Ave., Livingston, NJ 07039. E-mail:
[email protected]
“whooshing” sound in her left ear, increasing and decreasing in intensity in concordance with each heartbeat. There was no history of trauma or arteritis. Her initial diagnosis had been middle ear infection, which was treated with antibiotics, although there was no resolution of symptoms with this treatment. Her physical examination revealed fullness of the tissue overlying her left temporal area, and enlargement of the left superficial temporal artery. A bruit was detected and was associated with a thrill over the temporal artery in that region. The findings on physical examination warranted further study, and a color duplex ultrasound evaluation was obtained. A 12-MHz linear array pulsed Doppler transducer was used to evaluate the superficial temporal artery and the proximal segments of its parietal and frontal branches along with the adjacent vein. All vessels were evaluated with grayscale and color Doppler imaging to define regions of wall irregularity, luminal reduction, and/or disordered flow patterns. Doppler spectral velocity waveforms were obtained from the proximal, mid and distal segments of all visualized vessels. Results Spectral Doppler demonstrated a peak systolic velocity of 604 cm/sec and an end diastolic velocity of 395 cm/sec in the left superficial temporal artery (Figure 1). An arterialized flow pattern was well demonstrated in the adjacent vein (Figure 2). Gray-scale imaging revealed an enlarged temporal artery and a communication between the temporal artery and vein at the site of high velocity flow (Figure 3A–B). Color Doppler ultrasound also was used to confirm a communication between the temporal artery and vein (Figure 4). A preliminary diagnosis of arteriovenous fistula involving the superficial temporal artery and vein was made based on the findings obtained with gray scale, spectral and color Doppler.
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Figure 1 High velocity of AVF in left temporal artery.
The patient was then scheduled for surgical excision of the left temporal AV fistula for relief of her symptoms. Surgery revealed a branch of the superficial temporal artery connected to an enlarged accompanying vein, validating our color duplex ultrasound findings. The excised specimen measured 1.6 × 0.8 × 0.7 cm with pathologic confirmation of arteriovenous fistula of the superficial temporal artery (Figure 5). On her postoperative visit, the patient was doing well and made a good recovery. The bruit, thrill, and fullness of her scalp disappeared postoperatively and no complications were observed. On follow-up examination, the patient reported resolution of her initial presenting symptoms. Discussion
Figure 3 (A) Longitude view of the connection of left temporal artery and adjacent vein. (B) Transverse view of AVF.
Trauma to vasculature in any region can result in formation of an AVF. AVFs, including the superficial temporal artery, however, are quite rare.2,3 Moreover, the overwhelming majority of these fistulas are caused
by a preceding traumatic event⎯the absence of such in this particular case furthering its rarity. A variety of settings exist in which trauma disrupts the region of the superficial temporal artery, and trauma remains the most common etiological factor in the development of fistulas in this area.1,3,4 Trauma
Figure 2
Figure 4
Vascularized venous flow adjacent to temporal artery.
Transverse view of color duplex of AVF.
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bruit and possible thrill. This pulsation should disappear with compression of the artery proximal to the malformation (Terrier’s sign).3 Diagnosis Many methods have been used to evaluate AVF and include simple radiographs, Doppler ultrasonography, contrast angiography, and magnetic resonance imaging.1,3−5,12 Ultrasonography was the chosen diagnostic tool in this case. Demonstrating many benefits, and limited risk, it has been shown to be a valuable tool in similar vascular cases. The literature holds that temporal arteritis, or giant cell arteritis, is one particular vascular abnormality for which this imaging modality has proven very useful. In temporal arteritis, ultrasonography has improved the diagnostic accuracy of careful clinical examination without the need for biopsy.13 When applying this diagnostic method to this patient, the benefits were weighted against the risks. The procedure is painless, noninvasive, lacks any risk of radiation, and poses no health problems to the patient. Moreover, the cost of the procedure is considerably less than angiography or magnetic resonance imaging. These benefits, weighed against minimal risk, demonstrated that AV fistulae detection was an indication for sonographical usage.12 Management Figure 5 Photo of operative specimen. Temporal artery and branch on right, distended vein on left.
may be penetrating in nature, such as in stab wounds,3 glass,5 or mandibular condylar fracture.6 Blunt force trauma may also be causative in fistula formation, with reported occurrences including assault,7 motorcycle accidents,1 and childhood falls.8 A third, significant cause of superficial temporal artery AVF is those injuries sustained iatrogenically; these include hair transplantation,3 maxillofacial surgery,3 temperomandibular joint arthroscopy,9 and pterional craniotomy.10 AVF of the superficial temporal artery are much more common in men, occurring five times as frequently as in women. Also, the 20- to 40-year-old demographic is most susceptible to development of these fistulas, possibly in part because of their greater incidence of traumatic injury.4 Traumatic AVF need not present immediately; the latent period of clinical presentation may fall anywhere from 1 week to 15 years but most commonly is seen between 6 and 24 months.4 Clinical Manifestations The presentation of superficial temporal AVF is relatively similar among all cases. Patients typically report a triad of symptoms that include tinnitus, dizziness, and headache.2,11 On examination, an astute clinician will find a painless, pulsatile mass with a detectable
Multiple therapeutic approaches have been attempted in the treatment of superficial temporal artery AVF. Complete surgical excision, however, has been shown to be the treatment of choice.1 Excision allows for the abolishment of the AVF with minimal risk for recurrence.1 Another technique used for the treatment of superficial temporal artery AVF is endovascular embolization.1,5,9 Although effective in terminating the fistula, further surgery is often required to remove embolic materials caused by skin necrosis.1 A third technique used to treat these AV fistulae is simple ligation. However, similar to embolization, this technique often necessitates further surgery as extensive collaterals may cause the fistula to return.14 Conclusion Although extremely rare, a diagnosis of nontraumatic AVF of the superficial temporal artery is one that must not be overlooked. Clinical manifestations of this phenomenon are well recorded, and allow for an astute physician to make a correct diagnosis in the absence of trauma. These lesions can be managed appropriately with surgical excision and pose no threat to future health. This case illustrates the value of sonography as an accurate, cost-effective, readily accessible tool for confirmation of the clinical impression. As shown in this case study, duplex sonography complemented with color Doppler imaging can be used for identification of the localized region of high velocity flow, the associated arterialized venous flow patterns and the communication
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between the superficial temporal artery and adjacent vein findings, which yielded an accurate confirmatory diagnosis of superficial temporal artery arteriovenous fistula. References 1. Li F, Zhu S, Liu Y, et al. Traumatic arteriovenous fistula of the superficial temporal artery. J Clin Neurosci 2006;14:595–600. 2. Morandi X, Godey B, Riffaud L, Brassier G. Nontraumatic arteriovenous fistula of the superficial temporal artery. Otolaryngol Head Neck Surg 2004;124:588–589. 3. Johns DR, Swann KW, Heros RC. Spontaneous arteriovenous fistula of the superficial temporal artery. Surg Neurol 1987;27:273–276. 4. Chaudhary N, Chetter IC, Renwick PR. Arterio-venous fistulae of the superficial temporal artery: A case report and literature review. EJVES Extra 2001;2:102–104. 5. Whiteside OJH, Monksfield P, Steventon NB, Bynre J, Burton MJ. Endovascular embolization of a traumatic arteriovenous fistula of the superficial temporal artery. J Laryngol Otol 2005;119:322–324. 6. Long X, Cheng Y, Li X, Li H, Hu S. Arteriovenous fistula after mandibular condylar fracture. Int J Oral Maxillofac Surg 2004;62:1557– 1558.
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