Abstract

Background: Arteriovenous fistula (AVF) constitutes a pathological direct connection between an artery and a vein without an intervening capillary bed with a spectrum of high to low-grade malformation. Here, we present an unusual case of congenital neck AFV managed in a resource-limited setting in a war-zone area.

Case Description: A 43-year-old man presented with neck swelling and tinnitus since childhood with no history of trauma or surgical procedure. He was found to have reduced ejection fraction heart failure and atrial fibrillation and started on medications. Examination and bedside Gray scale and color Doppler ultrasound revealed a pulsatile high-flow vascular lesion around the left mandibular angle with thrill and dilated neck veins. A left external carotid artery catheter angiogram showed a large AVF hole with fast arteriovenous shunting distal to the origin of the facial artery draining into a venous sac and then to multiple superficial draining veins emptying into the anterior and external jugular veins. Multiple closure attempts at the fistula point using detachable coils and vascular plugs were unsuccessful. As a result, we treated the fistula surgically by disconnecting the draining veins and the presumed fistula and then resection of the venous sac guided by an intraoperative ultrasound. The patient tolerated the procedure, the tinnitus disappeared, and the heart failure improved at the 8-week follow-up echocardiogram. He developed local neurogenic pain that improved with 2 weeks of carbamazepine. Immediate postoperative neck computed tomography angiography confirmed fistula obliteration.

Conclusion: This case demonstrates the ability to consider patient and setting-tailored treatment options in managing complex carotid–jugular fistula and the utility of adjunctive intraoperative ultrasound in these procedures.

Keywords: Arteriovenous fistula, Endovascular embolization, External carotid artery, Surgical treatment, War zone

INTRODUCTION

Neck arteriovenous fistula (AVF) is a rare vascular pathology that usually constitutes a direct connection between the external carotid artery (ECA) branches and the jugular venous complex.[ 3 ] Most AVFs are acquired secondary to trauma, local invasive procedure, or infection.[ 3 ] Congenital AVFs are less common and usually progress slowly during adulthood.[ 3 ] They present with local neck swelling, pulsatile tinnitus, bruit, neurological sequelae, or hyperdynamic heart failure in high-flow vascular lesions.[ 3 , 4 ]

Current management of neck AFVs is tailored on an individual basis and includes either endovascular embolization, surgical treatment, or a combination of both.[ 4 ] Here, we shed light on the efforts and challenges of Saudi volunteering neurosurgery mission demonstrating a case of congenital ECA shunting fistula in a middle-aged patient who could not access specialized treatment in a limited-resources war-zone country. We present the perioperative images, endovascular trial of embolization, successful surgical resection of the fistula with the use of intraoperative ultrasound, and the online follow-up of the patient 6 months later.

CASE REPORT

A 43-year-old male presented with neck swelling and tinnitus since childhood. He denied a history of trauma or previous invasive procedure to the neck. He recently developed heart failure with reduced ejection fraction and atrial fibrillation and was started on medications by a local cardiologist. Examination revealed a pulsatile mass around the left mandibular angle with a thrill and dilated neck veins. Bedside Gray scale and color Doppler ultrasound showed a high-flow pulsatile vascular lesion. Due to limited resources and expertise at his place, the patient could not undergo proper investigations and treatment and was thus managed symptomatically. In the volunteering mission, we planned to investigate the lesion with a catheter angiogram and then decide on further management.

Under general anesthesia and through transfemoral approach, six vessels catheter cerebral and bilateral subclavian angiograms followed by carotid compression and balloon occlusion tests were performed. Catheter-based cerebral angiography demonstrated marked dilation of the left common carotid artery (CCA) and the left ECA, with a concomitantly reduced caliber of the left internal carotid artery (ICA). These findings were attributed to a large arteriovenous fistulous defect with rapid shunting of arterial flow toward the external cervical venous system. There was a left arteriovenous shunting distal to the origin of the facial artery that drained into a venous sac and then to multiple superficial draining veins emptying into the left external and anterior jugular vein [ Figures 1a - c ].

Figure 1:

(a-c) Catheter angiogram of the left common carotid artery (CCA). (a) Mid run injection showing dilated CCA (1), small caliber internal carotid artery (2) due to steal phenomenon, dilated external carotid artery (ECA) (3), early branches of the ECA as the following: superior thyroid artery (4), lingual artery (5), facial artery (6), and fistula take off (7) connected to a venous sac (8). (b) Late run injection showing the venous sac (1) and associated superficial draining veins. (c) Late run injection showing the extent of involvement of multiple superficial draining veins. (d) Intraoperative photograph after patient positioning showing the expected location of venous sac (white arrow), dilated draining veins (black arrow), and the marking of skin incision (black interrupted lines). (e) Use of intraoperative ultrasound to navigate the vascular lesion.

Injection of the remaining intra and extracranial major vessels including bilateral subclavian artery branches did not show any connection to the fistula. Manual compression of the left CCA, along with balloon occlusion testing, was performed. Subsequent right ICA injection demonstrated robust cross-filling from the contralateral ICA to the left cerebral hemisphere through a well-developed anterior communicating artery, as well as retrograde flow through the left ICA toward the left ECA fistula, indicative of high-flow arteriovenous shunting. Multiple endovascular attempts to occlude the fistulous communication using detachable coils and vascular plugs occlusion devices were unsuccessful despite adjunctive measures such as external manual carotid compression and temporary endovascular balloon occlusion aimed at reducing shunt flow, primarily due to the large-caliber fistulous defect and the presence of high-velocity arteriovenous shunting within the lesion. These anatomical and hemodynamic features posed a significant risk of device migration across the fistula into the venous circulation, with the potential for pulmonary embolism. A large detachable balloon was not available at that time. We avoided proximal arterial occlusion, as it may promote collateral recruitment of smaller feeding vessels to supply the fistula. These collateral channels are often more challenging to catheterize and visualize on subsequent imaging or surgery, thereby complicating future endovascular and surgical management. Therefore, we decided to proceed with surgical resection.

The left anterior cervical triangle was exposed using an oblique skin incision over the anterior border of the sternocleidomastoid muscle [ Figure 1d ]. Intraoperative ultrasound was used to navigate the vascular lesion [ Figure 1e ]. Further dissection was carried out to expose the carotid triangle [ Figure 2a ]. The ECA was identified and ligated at its most proximal part [ Figure 2b ] which softened the venous sac but did not deflate it. The sac was still filling through the fistula most likely from ipsilateral and contralateral normal anastomoses between the external and internal carotid blood supply in the head–and-neck region. Circumferential dissection around the venous sac [ Figure 2c ] was done to locate the fistulous site. Encountered draining veins were identified, coagulated, then ligated, and disconnected from the venous sac. Direct coagulation of the sac also helped to decrease its size and visualize the surrounding vessels. An arterial connection, the presumed fistula site [ Figure 2d ], was found and coagulated but before disconnection, a needle was used to aspirate the stagnant blood in the venous sac and completely deflate it. It remained deflated which confirmed that no other fistulous connections were present. After that, the venous sac was further coagulated, the fistula was ligated and disconnected, and the venous sac was taken out.

Figure 2:

(a-d) Intraoperative findings. (a) Exposure of the superficial draining veins (star) and left carotid triangle with its content; common carotid artery (CCA) (1), external carotid artery (ECA) (2), and internal carotid artery (3). (b) Yellow vessel loop was used to mark the CCA, and suture was used to ligate the ECA (white arrow). (c) Circumferential dissection around the venous sac (white arrow) to locate the fistula point, notice that the sac was still filling even after ECA ligation. (d) Demonstration of the fistula site (white arrow) and partially deflated venous sac close to it after disconnecting multiple draining veins and coagulation of the sac itself with bipolar diathermy. (e) Postoperative computed tomography angiogram of the neck (although limited due to technical contrast contamination) showing absence of shunting to the venous structures during arterial phase (star: left common carotid artery) with some contrast extravasation in the surgical bed. (f) Photograph of the wound 6 months postoperatively showing good healing and absence of any swelling suggestive of recurrence.

The patient recovered well postoperatively and his tinnitus disappeared. Immediate postoperative computed tomography angiography of the neck confirmed the exclusion of the arteriovenous shunting [ Figure 2e ]. The patient was followed up a week later through an online instant messaging application, and he reported numbness and pain in the left lower mandibular area likely due to local injury of small trigeminal sensory branches. We prescribed him a short course of carbamazepine which alleviated his symptoms. An 8-week echocardiogram showed improvement in his cardiac ejection fraction. About 6 months later, the patient was followed up online and he reported no recurrence of his neck swelling with improvement in his overall health [ Figure 2f ].

DISCUSSION

AVFs involving the ECA are rare vascular anomalies, typically categorized as either congenital or acquired – often secondary to trauma, infection, or iatrogenic causes. Despite their rarity, symptomatic AVFs commonly present with neurological deficits or cardiovascular compromise, warranting definitive intervention. Treatment options include endovascular embolization, surgical resection, or a hybrid approach in complex or recurrent cases.[ 2 ]

The optimal surgical strategy generally involves complete resection of the fistulous connection along with the venous sac, with vascular reconstruction as needed to prevent recanalization and preserve arterial continuity.[ 5 ] Endovascular techniques follow a similar principle of fistula exclusion, using materials such as detachable coils or balloons.[ 1 ] While embolization is appealing due to its minimally invasive nature, it may not always be feasible – particularly in resource-limited settings or high-flow lesions where tool availability and flow dynamics pose challenges.[ 3 ]

In the presented case, the patient denied any history of trauma, supporting the likelihood of a congenital AVF. His late presentation likely reflects long-standing underdiagnosis due to limited local healthcare access. Endovascular treatment was initially considered but abandoned due to the unavailability of necessary tools. Given the high-flow nature of the lesion and the patient’s inability to access consistent specialist follow-up, surgical resection emerged as the most definitive and durable treatment option.

The surgical team navigated a series of logistical and technical challenges, requiring adaptive planning and resourceful execution. A multidisciplinary volunteer team was deployed, including a neurosurgeon, interventional neuroradiologist, anesthesiologist, and support staff. The angiographic evaluation was performed in a repurposed cardiac angiography suite maintained through charitable efforts, and neurointerventional supplies were brought in by the mission team. Surgery was performed in an operating room lacking a microscope and advanced imaging such as indocyanine green angiography, underscoring the necessity for flexibility and innovation in global health missions.

Surgical technique and innovations

This case exemplifies practical surgical strategies for complex vascular pathologies in austere settings. A generous, obliquely oriented cervical incision – similar to that used in carotid endarterectomy – was made along the anterior border of the sternocleidomastoid muscle, extending from just below the mastoid process to the suprasternal notch (approximately 12 cm). This approach enabled broad exposure of the carotid triangle and adjacent vascular structures without the use of a surgical microscope.

After wide dissection through the anterior cervical triangle, intraoperative portable ultrasound was used to identify the vascular lesion, enabling real-time navigation and anatomical assessment. This tool – more widely available and user-friendly than fluoroscopy or intraoperative dye studies – proved essential for mapping the lesion and confirming resection endpoints. Surgical dissection proceeded methodically, focusing first on identifying and ligating multiple draining veins, followed by circumferential mobilization of the venous sac. The sac was gradually deflated through aspiration and bipolar coagulation, which facilitated its safe removal. The presumed fistula site was identified and tested with bulldog clamps before being definitively coagulated and ligated, confirming cessation of flow and obviating the need for intraoperative flow measurements or dye studies. The procedure was adapted not only to the available resources but also to the patient’s complex medical background, including heart failure and atrial fibrillation. Intraoperative management required a vigilant anesthesia team prepared for cardiovascular instability.

Postoperative follow-up was conducted through remote communication, which proved essential in maintaining continuity of care. Although formal imaging follow-up was limited, the patient’s clinical improvement – resolution of tinnitus, improved cardiac function, and stable wound healing – confirmed the success of the intervention.

This experience reinforces the importance of flexible surgical planning, creative use of available tools, and cross-disciplinary coordination. It provides a replicable framework for global neurosurgical outreach efforts, particularly those targeting vascular pathologies in underserved regions. Portable imaging, systematic dissection techniques, and thoughtful decision-making can allow complex surgeries to be performed safely, even in environments with significant resource constraints.

CONCLUSION

Neck arteriovenous shunting negatively impacts patients’ health and usually requires treatment. Early and tailored management is usually feasible in advanced healthcare settings; however, in limited-resources and war-zone countries, patients are symptomatically managed, and definitive treatment might be possible with volunteering medical missions despite the presenting challenges. This case provides a perspective and guide for global neurosurgery volunteering missions.

Ethical approval:

Institutional Review Board approval is not required.

Declaration of patient consent:

The authors certify that they have obtained all appropriate patient consent.

Financial support and sponsorship:

Nil.

Conflicts of interest:

There are no conflicts of interest.

Use of artificial intelligence (AI)-assisted technology for manuscript preparation:

The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.

Disclaimer

The views and opinions expressed in this article are those of the authors and do not necessarily reflect the official policy or position of the Journal or its management. The information contained in this article should not be considered to be medical advice; patients should consult their own physicians for advice as to their specific medical needs.

References

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