Carotid-cavernous fistulas (CCFs) are abnormal arteriovenous communications between the carotid arterial system and the cavernous sinus, most frequently resulting from traumatic head injury. These lesions can lead to debilitating ophthalmologic and neurologic sequelae, including vision loss, proptosis, cranial nerve deficits, and intracranial hemorrhage, due to venous hypertension and vascular steal phenomena [2]. Consequently, while endovascular intervention remains the gold standard for treatment, the optimal approach must reconcile two competing priorities: complete fistula occlusion and preservation of parent vessel patency to prevent ischemic complications [1,3].

Traditional endovascular strategies, such as transarterial or transvenous embolization with coils or liquid embolics, often achieve fistula closure but may require sacrifice of the internal carotid artery (ICA) in complex cases, posing risks of cerebral hypoperfusion. Covered stents have emerged as a promising alternative, enabling direct exclusion of the fistula while maintaining ICA integrity [4]. However, their intracranial application has been historically limited by technical challenges, including navigational constraints in tortuous anatomy and the risk of stent thrombosis or endoleaks [4,5].

This case report describes a 23-year-old male with CCF presenting seven months post-injury, a delayed and atypical timeline underscoring the heterogeneity of symptom onset in neurovascular trauma. The patient’s high-flow direct CCF, compounded by an indirect dural supply, demanded a staged approach combining coil embolization of accessory feeders and carotid reconstruction with a 5 mm PK Papyrus covered stent—a coronary device repurposed for neurovascular use. The deployment leveraged a novel tri-axial catheter system to overcome anatomical barriers, demonstrating the feasibility of large-diameter stents in intracranial interventions.

A 23-year-old male presented with seven months of persistent left eye pain, redness, and proptosis following a motor vehicle collision. Ophthalmologic examination revealed left conjunctival injection, proptosis, and diplopia, with a cranial nerve (CN) VI deficit. Subsequently, a computed tomographic (CT) angiogram confirmed bilateral CCFs, characterized by dilated cavernous sinuses and superior ophthalmic veins (SOVs) bilaterally (Fig. 1).

Cerebral angiography demonstrated a high-flow left CCF with compromised distal ICA flow. It also showed early filling of the cavernous sinus and retrograde venous drainage into the SOV. The fistula had both direct and indirect components, with arterial supply from an ICA transection and dural branches of the middle meningeal artery (MMA).

Following occlusion of the indirect component with multiple coils (Fig. 2), carotid reconstruction was performed to treat the direct component of the CCF. A Benchmark BMX 81 catheter (Penumbra, Inc., Alameda, CA, USA) was used along with Phenom 27 and Phenom Plus microcatheters (Medtronic, Inc., Minneapolis, MN, USA) to select the left middle cerebral artery over a 0.014-inch Synchro wire (Stryker Corp., Salt Lake City, UT, USA). The Synchro wire was then exchanged for a 0.014-inch Mailman guidewire (Boston Scientific Corp., Marlborough, MA, USA) and positioned in the M2/M3 segment. Using the Phenom microcatheters, the BMX81 catheter was advanced across the lesion, which allowed for a degree of carotid remodeling and expansion to safely accommodate a larger diameter stent. After removing the microcatheters, a 5 × 20 mm PK Papyrus stent (Biotronik Inc., Lake Oswego, OR, USA) was advanced over the guidewire and positioned appropriately. The BMX81 catheter was then carefully retracted to ensure the stent remained in position. Balloon inflation was performed to nominal pressure, followed by additional balloon expansion of the proximal and distal stent segments to prevent type I endoleak (Fig. 3).

Post-procedure imaging confirmed successful occlusion of the fistula with restored flow to the distal ICA (Fig. 4). The patient was discharged the following day on dual antiplatelet therapy (Aspirin 81 mg and Ticagrelor 90 mg twice daily) with no neurological deficits. At the five-month follow-up, the patient remained asymptomatic with no recurrence of symptoms.

The management of traumatic CCFs requires balancing fistula occlusion with preservation of ICA patency to prevent ischemic complications. This case highlights the successful application of a coronary covered stent, the PK Papyrus, deployed via a tri-axial system, to address a complex high-flow CCF while maintaining vascular integrity.

To our knowledge, this is the first report of a 5 mm diameter PK Papyrus covered stent deployed in neurovascular intervention and the first description of the arterial stent delivery technique utilizing a 0.081” catheter system. The use of covered stents for CCF has only been explored on limited case series [4].

Larger profile stents may increase the risk of dissection and treatment failure during navigation of the carotid siphon. The PK Papyrus provides a novel solution to some of these problems; however, without the use of novel 6Fr intermediate catheters, navigation remains limited. In this regard, the use of a new generation 081 catheter to cross the rupture point provides a degree of carotid remodeling or expansion, which helped to safely accommodate a larger diameter stent, reducing the risk of dissection and stent migration. Our approach stands out from previous reports by using a near no-shelf intermediate catheter as scaffolding to deploy the endograft across the fistula with exceptional precision. Navigation through the carotid siphon can be challenging due to its tortuosity, particularly when using conventional 6Fr intermediate catheters, which may limit access and stability. In contrast, the 0.081-inch Benchmark BMX catheter provided improved support, enabling safer and more precise stent placement. This approach facilitated carotid remodeling, reducing the risk of vascular dissection and stent migration, challenges often encountered with larger-profile stents. The PK Papyrus stent offers a novel solution to these issues, but its navigation remains limited without the aid of advanced intermediate catheters.

Although the patient’s favorable clinical outcome, demonstrated by immediate fistula occlusion and maintained patency of the ICA at five-month follow-up, indicates the potential effectiveness of this novel approach, additional research is necessary. Further studies with larger cohorts and extended follow-up durations are required to comprehensively evaluate the long-term safety, reliability, and possible complications. Moreover, subsequent research could investigate improvements in delivery systems and stent designs specifically adapted for neurovascular applications.

This case report presents the first documented use of a 5 mm PK Papyrus covered stent in treating a traumatic carotid-cavernous fistula via a tri-axial access technique. Our novel approach enabled precise stent deployment and successful occlusion of the fistula while preserving carotid patency. The patient’s favorable outcome highlights the potential of covered stents in neurovascular interventions, offering a viable alternative to traditional embolization techniques. Future studies are needed to further establish the safety and efficacy of this approach in larger patient cohorts.