Endovascular treatment of superior petrosal sinus dural arteriovenous fistulas via combined transarterial and transvenous approach: Lessons from 2 cases

Abstract

Superior petrosal sinus (SPS) dural arteriovenous fistulas (DAVFs) often require endovascular treatment (EVT), with a combined transarterial/transvenous approach being a rare alternative. Case 1 involved a 61-year-old male with subarachnoid hemorrhage (SAH) diagnosed with a non-sinus-type SPS DAVF. The endovascular treatment utilized a combined transarterial/transvenous approach: A transvenous dual-lumen mini-balloon catheter was advanced into the SPS origin via the internal jugular vein (IJV) and sigmoid sinus (SS), while a transarterial balloon catheter was positioned in the external carotid artery (ECA). After temporary occlusion of the external carotid artery, transvenous Onyx injection failed to penetrate the fistula, the patient experienced a new postoperative subarachnoid hemorrhage, which resolved spontaneously, and follow-up angiography at 2 months confirmed complete DAVF obliteration. Case 2 involved a 63-year-old male diagnosed with a sinus-type SPS DAVF, where a combined transarterial/transvenous approach was employed: The carotid artery feeding arteries were embolized, the dilated SPS origin was catheterized via the internal jugular vein and sigmoid sinus, and the DAVF-feeding aneurysm on the basilar artery perforating artery was catheterized, followed by coiling of both the dilated SPS origin and the aneurysm, resulting in complete DAVF obliteration. Postoperatively, the patient reported facial numbness, which resolved after a 1-month course of mecobalamin tablet therapy. These cases demonstrate that for non-sinus-type SPS DAVF, occlusion of the SPS alone may carry a risk of hemorrhagic complications due to lack of fistula-site embolization. In contrast, for sinus-type SPS DAVF, embolizing the dilated SPS origin (as the fistula site) and the feeding artery may suffice for effective treatment.

Introduction

Dural arteriovenous fistula (DAVF) is a rare vascular abnormality characterized by pathological arteriovenous shunting. The pathogenesis involves either the opening of preexisting microshunts within the dural layer or angiogenesis-driven formation of new arteriovenous connections [1]. The superior petrosal sinus (SPS) is an uncommon location for DAVFs, with SPS DAVFs accounting for approximately 5% of all intracranial DAVFs [2]. For SPS DAVFs, computed tomography (CT) and magnetic resonance (MR) images can only reveal indirect findings (eg, abnormal venous drainage). CT/MR vascular imaging can identify the venous drainage pathway. Currently, digital subtraction angiography (DSA) remains the gold standard for SPS DAVFs; it provides precise angioarchitecture of the DAVF, including the origin of feeding arteries, the location of the fistula point, and drainage pathway.

SPS DAVFs typically present with aggressive features due to cortical venous drainage, rarely involve intracranial pial arteries as feeders, and treatment is often necessary [3]. Currently, endovascular treatment (EVT) has emerged as a first-line option for DAVFs, including transarterial embolization (TAE) and transvenous embolization (TVE) [3,4]. SPS DAVFs can be classified as non-sinus-type and sinus type [5,6]. For non-sinus-type SPS DAVFs, TAE can serve as the primary intervention [[7], [8], [9]]. When anatomical constraints render TAE challenging or when microsurgery proves difficult for non-sinus-type SPS DAVFs, a combined transarterial/transvenous approach may be considered as a rare alternative. For sinus-type SPS DAVFs, a combined transarterial/transvenous approach may suffice.

The SPS communicates medially with the cavernous sinus and laterally with the transverse-SS junction. It is easily accessed via the internal jugular vein (IJV) and SS. TVE for non-sinus-type SPS DAVFs is challenging due to the difficulty of retrograde delivery of liquid embolic agent to the fistula point, even when the feeding arteries are temporarily occluded. This report presents such a non-sinus-type SPS DAVF with unsuccessful EVT, highlighting the technical challenges. Furthermore, this report also describes a sinus-type SPS DAVF that achieved successful EVT via a combined transarterial/transvenous approach. This case involved an extremely rare basilar artery perforating artery as the main feeding artery with multiple tandem aneurysms, a previously unreported condition.

By reporting these 2 SPS DAVF cases, valuable lessons can be learned regarding the EVT of SPS DAVFs via the combined transarterial/transvenous approach, making this report of 2 cases clinically significant.

Case presentation

Case 1

A 61-year-old male developed sudden severe headache with vomiting 13 days before admission. Initial CT revealed subarachnoid hemorrhage (SAH), which was managed conservatively at a local hospital. Follow-up CT on days 1 and 4 post-onset demonstrated resolution of the SAH (Fig. 1A). On admission, his symptoms had resolved. Neurological examination revealed intact consciousness, normal muscle strength (Grade 5/5) in all extremities. DSA confirmed a left SPS DAVF, fed by the left sphenopalatine artery (Vidian artery), the left internal carotid artery (ICA), and the left anterior inferior cerebellar artery (AICA), draining into the SPS (Figs. 1B-D). This DAVF was of the non-sinus type. The patient reported no personal history of hypertension, diabetes mellitus, infectious diseases, surgical interventions, or cerebrovascular events and had no known family history of intracranial hemorrhage. Given the etiology of the SAH from the SPS DAVF and all preoperative tests (laboratory and imaging) confirming eligibility for general anesthesia and EVT, the EVT was subsequently performed.

Fig. 1.

Diagnostic images of Case 1: (A) Upper panel: Initial CT demonstrates SAH in the left ambient cistern (asterisk). Middle panel: 24-hour follow-up CT shows partial SAH resorption (asterisk). Lower panel: Day 4 CT reveals near-complete SAH resolution (asterisk). (B) DSA images of the left ECA in anteroposterior (left panel) and lateral (right panel) views demonstrate an SPS DAVF (asterisks), supplied by a branch of the SPA (arrows) with venous drainage into the SPS (arrowheads). (C) DSA images of the left ICA in lateral (left panel) and anteroposterior (right panel) views demonstrate the supply from the dural branch of the ICA (arrow) to the DAVF (asterisk) with venous drainage into the SPS (arrowheads). (D) DSA images of the left VA in anteroposterior (left panel) and lateral (right panel) views demonstrate a dural branch of the left AICA (arrow) supplying the DAVF (asterisk), with venous drainage into the SPS (arrowheads). AICA: anterior inferior cerebellar artery; CT, computed tomography; DAVF, dural arteriovenous fistula; DSA, digital subtraction angiography; ECA, external carotid artery; ICA, internal carotid artery; L, left; SAH, subarachnoid hemorrhage; SPA, sphenopalatine artery; SPS, superior petrosal sinus; VA, vertebral artery.

Under general anesthesia, a combined transarterial/transvenous approach was used, utilizing right femoral venous access and left femoral arterial access. A 6F guiding catheter was advanced through the femoral artery and positioned in the left common carotid artery. Simultaneously, an 8F guiding catheter was inserted via the femoral vein and advanced to the origin of the left IJV. Under transarterial roadmap guidance, a 5F distal access catheter was advanced through the 8F guiding catheter to reach the SPS termination via the SS. Subsequently, a TJWY dual-lumen mini-balloon catheter (2.2 mm × 9 mm; TJWY Medical Co, Ltd, Beijing, China) was advanced over an “ASAHI CHIKAI 0.010” guidewire (ASAHI INTECC Co, Ltd.,Seto, Japan) and precisely positioned within the left SPS origin (Fig. 2A). The 6F guiding catheter was then advanced from the left common carotid artery into the external carotid artery (ECA) origin, where a 4 mm × 20 mm balloon was deployed.

Fig. 2.

Therapeutic course images of Case 1: (A) Left panel: DSA of the left carotid artery demonstrates a distal access catheter (red circle) positioned within the SS at the SPS termination via the IJV, with the asterisk indicating the fistula point and the arrow indicating the direction of blood flow. Right panel: Roadmap image shows a dual-lumen mini-balloon catheter (arrow) within the SPS origin near the DAVF (asterisk). (B) Left panel: Roadmap image demonstrates an inflated balloon (arrow) positioned in the left ECA to occlude blood flow. Right panel: Roadmap image shows the inflated dual-lumen mini-balloon (arrow) within the SPS. (C) Upper panel: X-ray image shows the inflated dual-lumen mini-balloon (arrow) with Onyx casting. Lower panel: X-ray image shows the Onyx morphology after dual-lumen mini-balloon catheter removal. Onyx casting failed to penetrate the fistula point (asterisk), occluding only the proximal draining vein. (D and E) Arterial (left panel) and venous (right panel) phases of DSA images of the left carotid artery (panel D) and the left vertebral artery (panel E) demonstrate no sign of DAVF. (F) Upper panel: Xper-CT shows no bleeding. Lower panel: Xper-CT shows the Onyx (red circle). CT, computed tomography; DAVF, dural arteriovenous fistula; DS, digital subtraction angiography; ECA, external carotid artery; IJV, internal jugular vein; L, left; SPS, superior petrosal sinus; SS, sigmoid sinus.

After simultaneous inflation of both balloons, Onyx-18 liquid embolic system (Medtronic, Irvine, CA, USA) was carefully injected through the transvenous TJWY dual-lumen mini-balloon catheter into the SPS (Fig. 2B). Once the Onyx did not move toward the fistula point, the Onyx injection stopped and waited. During 5 minutes, 0.5 mL of Onyx was injected. Although the Onyx successfully occluded the SPS origin and the proximal segment of the superior petrosal vein (SPV) complex, it failed to reach the actual fistula point (Fig. 2C). Immediate DSA demonstrated disappearance of the DAVF (Figs. 2D and E). Xper-CT confirmed no intraoperative bleeding and identified the Onyx location (Fig. 2F). Subsequently, the patient’s blood pressure was controlled at a level below 120 mmHg.

At 1 hour post-EVT, the patient regained consciousness with preserved motor function in all extremities but complained of persistent headache. Postoperative 12-hour CT identified new SAH (Fig. 3A). Sedative therapy and blood pressure management were maintained until postoperative day 3, when repeat CT demonstrated SAH resolution (Fig. 3B). The patient’s headache subsided. On postoperative day 4, MR examination showed no evidence of acute brain infarction or residual DAVF (Figs. 3C-E), prompting discharge. After 1 month of home recovery, the patient resumed normal activities. At the 2-month follow-up DSA, confirmed complete obliteration of the DAVF (Fig. 3F).

Fig. 3.

Postoperative and follow-up images of Case 1: (A) Postoperative 12-hour CT images show new acute SAH (asterisk in left panel) localized to the left ambient cistern and demonstrate the DAVF location (arrow in right panel). (B) Day 3 CT images show SAH absorption. (C) Day 4 MR images show SAH resolution on T2-weighted imaging (left panel), with diffusion-weighted imaging excluding acute brain infarction (right panel). (D and E) MR angiography (panel D) and MR venography (panel E) show no DAVF. (F) 2-month follow-up DSA images demonstrate complete obliteration of the SPS DAVF in the arterial phase of anteroposterior (left panel) and lateral (middle panel) views, as well as in the late arterial phase of the lateral view (right panel). CT, computed tomography; DAVF, dural arteriovenous fistula; DSA, digital subtraction angiography; L, left; MR, magnetic resonance; SAH, subarachnoid hemorrhage; SPS, superior petrosal sinus.

Case 2

A 63-year-old male was diagnosed with multiple intracranial aneurysms 2 weeks earlier via CT angiography (Fig. 4A). Neurological examination revealed normal muscle strength (Grade 5/5) in all extremities and no pathological reflexes. The patient denied personal history of hypertension, diabetes mellitus, or cerebrovascular events. The patient had no known family history of intracranial aneurysm. All preoperative tests confirmed eligibility for general anesthesia and EVT, which was subsequently performed.

Fig. 4.

Diagnostic images of Case 2: (A) Computed tomography angiography reveals 2 aneurysms (arrows) at the distal left SCA and adjacent to the basilar artery. (B) DSA of the left ICA demonstrates that the tentorial branch of the ICA (arrow) supplies an SPS DAVF (asterisk), with drainage into the SPS (arrowhead). (C) DSA images of the left VA in anteroposterior (left panel) and lateral (right panel) views show that the left perforating artery of the basilar artery with 2 tandem aneurysms (arrows in left panel) supplies an SPS DAVF. The DAVF is located at the aneurysmal dilated SPS origin (asterisks) and drains into the SPS (arrowheads), SS, and IJV. The long arrow in right panel indicates blood flow direction. (D) DSA of the left external carotid artery shows the AMA (arrow) supplies the DAVF (asterisk) and drains into the SPS (arrowhead). (E) Microcatheter angiography confirms that the left SCA does not supply the DAVF. AMA, accessory meningeal artery; DAVF, dural arteriovenous fistula; DSA, digital subtraction angiography; ICA, internal carotid artery; IJV, internal jugular vein; L, left; SCA, superior cerebellar artery; SPS, superior petrosal sinus; SS, sigmoid sinus; VA, vertebral artery.

Under general anesthesia, a combined transarterial/transvenous approach was established via the right femoral artery and vein. Transarterial DSA revealed a left SPS DAVF supplied by the left accessory meningeal artery (AMA), the tentorial branch from the left ICA, and a left perforating branch of the basilar artery (associated with multiple tandem aneurysms at the proximal segment). The arteriovenous shunting was located at the origin of the left SPS, accompanied by aneurysmal dilatation, with drainage into the SPS and subsequently into the transverse sinus and SS (Figs. 4B-E).

TAE procedure via the AMA was performed. A 4.5F distal access catheter (AccuMedical, Beijing, China) was advanced through a 6F guiding catheter into the maxillary artery. Under the guidance of a Synchro 14 microguidewire (Stryker Neurovascular, Fremont, CA, USA), an Echelon-10 microcatheter (Medtronic, Irvine, CA, USA) was navigated via the middle meningeal artery (MMA) to reach the distal AMA. During 1 minute, 0.5 mL of Onyx-18 was injected. DSA confirmed complete occlusion of the feeding arteries from the AMA and the tentorial branch from the ICA to the DAVF (Figs. 5A and B).

Fig. 5.

Therapeutic course images of Case 2: (A) Left panel: DSA of the left ECA shows the AMA (arrow). Right panel: Roadmap image confirms catheterization of the AMA. (B) DSA of the left carotid artery demonstrates no evidence of DAVF after Onyx embolization via the AMA, indicating occlusion of the ECA and internal carotid artery feeders to the DAVF. (C) Roadmap images in anteroposterior (left panel) and lateral (right panel) views show that the dilated SPS origin (asterisks) was catheterized via the IJV, SS, and SPS. (D) Roadmap image shows the large aneurysm (arrow) on the left basilar artery perforating artery was catheterized. (E) Roadmap image shows the aneurysm and dilated SPS origin were being coiled. (F) DSA images of the left VA in arterial (left panel) and venous (right panel) phases demonstrate complete obliteration of the DAVF following coiling of the aneurysm and the SPS origin. (G) Left panel: Xper-CT showing no bleeding, with asterisk-marked DAVF location. Reconstructed CT (middle panel) and X-ray image (right panel) demonstrate the Onyx, coiled aneurysm (AN), and coiled SPS origin (asterisk). AMA, accessory meningeal artery; AN, aneurysm; CT, computed tomography; DAVF, dural arteriovenous fistula; DSA, digital subtraction angiography; ECA, external carotid artery; SPS, superior petrosal sinus; IJV, internal jugular vein; L, left; SS, sigmoid sinus; VA, vertebral artery.

The left intracranial vertebral artery was catheterized using the 4.5F distal access catheter via the 6F guiding catheter. Under transarterial roadmap guidance of the vertebral artery, a 6F transvenous guiding catheter was advanced into the left IJV. An Echelon-10 microcatheter was then navigated through the SPS to the fistula point (origin of the left dilated SPS) via the SS (Fig. 5C). Another Echelon-10 microcatheter was advanced into the large aneurysm of the perforating artery of the basilar artery (Fig. 5D). The aneurysm and the dilated SPS origin were coiled via the combined transarterial/transvenous approach, resulting in complete obliteration of the aneurysm and SPS DAVF (Figs. 5E and F). Postoperative CT confirmed the location of the DAVF and the embolic agent (Fig. 5G).

Postoperatively, the patient reported persistent left facial numbness without facial palsy or other neurological deficits. On postoperative day 3, MR imaging demonstrated no evidence of acute brain infarction (Fig. 6A). Both MR angiography and venography findings were negative for aneurysm and DAVF (Fig. 6B). After a 1-month course of Mecobalamin Tablets (0.5 mg, oral, 3 times daily; Eisai [China] Pharmaceutical Co, Ltd, Suzhou), his left facial numbness showed near-complete resolution.

Fig. 6.

Postoperative day 3 MR images of Case 2: (A) MR images demonstrate no acute brain infarction in diffusion-weighted imaging (upper panel) and T2-weighted imaging (lower panel). The asterisks indicate the location of the DAVF. (B) MR angiography (upper panel) and MR venography (lower panel) show no evidence of DAVF and aneurysm. DAVF, dural arteriovenous fistula; MR, magnetic resonance.

Discussion

SPS DAVFs are classified into 2 distinct types: the non-sinus type, located at the petrous ridge dura not directly around the SPS origin; and the sinus type, located around the origin of the dilated SPS [10]. SPS DAVFs frequently recruit the petrosal branch of the MMA, tentorial branch of the ICA, dural branches of the occipital artery, and ascending pharyngeal artery as feeding arteries, subsequently draining into the SPS, SPV, and their cortical venous tributaries [3]. In some cases, the non-sinus type of SPS DAVF may not drain into the SPS due to its occlusion and drains exclusively into the SPV; this condition is termed petrous ridge DAVF (Fig. 7A). The SPS DAVF in Case 1 corresponds to the non-sinus type, demonstrating a rare arterial supply pattern from the Vidian artery, dural branches of the ICA, and the AICA, exhibiting indirect drainage into the SPS. The DAVF in Case 2 corresponds to the sinus type, featuring an even rarer arterial supply pattern from the AMA, the tentorial branch of the ICA, and a perforating artery of the basilar artery, exhibiting direct drainage into the SPS.

Fig. 7.

Transarterial versus transvenous strategies for 2 DAVFs: (A) Transarterial embolization for a petrous ridge DAVF. Panel 1: DSA of the right carotid artery demonstrates a DAVF (asterisk) draining into a cortical vein with aneurysmal dilation (arrowhead). Panel 2: Three-dimensional DSA of the left external carotid artery reveals feeding arteries to the DAVF (asterisk) originating from the MMA, OA, and SPA (arrows). Panel 3: Roadmap image confirms the meningeal branch of the OA is utilized as the transarterial access route, with the microcatheter (arrow) positioned near the fistula site (asterisk). Panel 4: Unsubtracted DSA demonstrates Onyx penetration of the fistula (asterisk) via the OA. Panel 5: Immediate post-procedural DSA confirms complete obliteration of the DAVF. Panel 6: Reconstructive Xper computed tomography displays the Onyx casting along the right petrous ridge (asterisk). (B) Transvenous embolization for a CS-DAVF. Panel 1: DSA images of the right carotid artery (left panel) and left carotid artery (right panel) demonstrate a CS-DAVF (asterisks) with drainage into the IPS, FV, and CV. Panel 2: Roadmap images confirm catheterization of the IPS (left panel) and selective catheterization of the CS (arrow) via the IPS (right panel). Panel 3: X-ray images show initial coil deployment within the CS to reduce blood flow (left panel), followed by subsequent Onyx casting to pack the CS (right panel). Panel 4: Immediate post-procedural DSA images of the right carotid artery (left panel) and left carotid artery (right panel) confirm complete obliteration of the CS-DAVF. CS, cavernous sinus; CV, cortical vein; DAVF, dural arteriovenous fistula; DSA, digital subtraction angiography; FV, facial vein; IPS, inferior petrosal sinus; L, left; MMA, middle meningeal artery; OA, occipital artery; R, right; SPA, sphenopalatine artery.

Cognard classification categorizes DAVFs with cortical/perimedullary drainage as high-grade lesions [11]. In Case 1, the SPS DAVF initially presented as a low-grade lesion due to exclusive drainage into the SPS. However, the onset of SAH in this case confirmed either fistulous point rupture or occult cortical venous involvement, thereby warranting classification as high-risk. In Case 2, the SPS DAVF received its feeding artery from a perforating artery of the basilar artery and was associated with multiple tandem flow-related aneurysms, thus also qualifying as high-risk. High-risk SPS DAVFs necessitate immediate intervention, with EVT being the first-line treatment modality.

EVT for DAVFs aims for complete obliteration of the fistula point and proximal draining vein through liquid embolic agent penetration. TAE is viable for SPS DAVFs; small-caliber feeding arteries may limit successful technical approach. TAE was contraindicated in Case 1 due to the absence of MMA/AMA feeders, which constitute the principal arterial supply for this DAVF [12]. The dural branches of the ICA and AICA were deemed unsuitable for microcatheterization because of their small caliber and unclear anatomical courses. Although the enlarged Vidian artery seemed like a potential alternative TAE route, extreme vascular tortuosity made microcatheter navigation to the fistula site extremely challenging. Additionally, the Vidian artery's critical role in the vidian anastomotic network—with its connections to the AMA, ascending pharyngeal artery, and ICA-derived inferolateral trunk—significantly increased the risks of TAE through this route, leading to the TAE being abandoned [13,14]. In Case 2, despite AMA supply, its tortuous course and remote anatomical location to the fistula point precluded effective delivery of embolic material, ultimately resulting in TAE failure.

In these 2 cases, microsurgery or alternative EVT routes became necessary. Microsurgery remains a viable option for SPS DAVFs, complete elimination can be achieved by disconnecting the pathologic veins from the dural sinus at their entry point [15]. However, microsurgery may pose significant technical challenges due to the deep-seated location, requiring either a subtemporal, presigmoid, or retrosigmoid approach. These routes entail inherent risks such as potential injury to the facial, acoustic, and trochlear nerves, along with possible vestibular/cerebellar dysfunction and cerebrospinal fluid fistula [16,17]. In Case 2, concomitant flow-related aneurysms requiring microsurgical intervention introduced additional challenges. Given the procedure’s complexity and risks, microsurgery was contraindicated in both cases. A combined transarterial/transvenous approach was selected.

In the combined transarterial/transvenous approach for SPS DAVFs, the transarterial procedure aims to reduce arterial blood supply to the DAVF, thereby facilitating subsequent TVE. In Case 1, this was achieved through temporary ECA occlusion using a balloon catheter. The routine 6F transarterial guiding catheter provided adequate delivery capacity for the balloon catheter. In Case 2, TAE via the AMA effectively occluded blood supply from the carotid artery system. A 4.5F distal access catheter introduced through a 6F guiding catheter provided adequate support for AMA catheterization. TVE was subsequently considered. Successful TVE for SPS DAVFs has been reported, including those by Branco et al. [18], Ng et al. [19], Nishihori et al. [8], and Hirata et al. [9]. In these cases, the SPS DAVFs belong to sinus type; only coiling the SPS cured them, similar to cavernous sinus DAVFs, where only packing the cavernous sinus can be effective (Fig. 7B).

In Case 1, the SPS DAVF was a non-sinus type, with the arteriovenous shunting point located within the dura between the SPS and SPV, not involving the SPS origin. SPS coiling alone would be ineffective due to sinus wall noninvolvement. Thus, the “pressure cooker” technique can be expected to propel Onyx in a retrograde delivery pattern to penetrate the DAVF. For the “pressure cooker” technique, a double microcatheter approach, where 1 microcatheter performs coiling while the other delivers Onyx, can be considered. However, due to the SPSs limited space and technical complexity, a dual-lumen mini-balloon catheter was deployed at the SPS origin to establish the “pressure cooker” effect. In Case 2, the SPS DAVF was of the sinus type, with the arteriovenous shunting point located at the aneurysmal dilation of the SPS origin. Coiling the SPS origin obliterated the DAVF. In contrast, Onyx injection may lead to retrograde migration into the SPS, SS, and IJV. Therefore, only a transvenous Echelon-10 microcatheter was used to perform coiling. Due to the presence of high-risk flow-related aneurysms on the perforating artery of the basilar artery (serving as a feeder), the large aneurysm was coiled simultaneously.

In Case 1, the retrograde Onyx casting failed to penetrate the fistula point, only occluding the SPS and its adjacent veins, indicating that non-sinus-type SPS DAVF may not be a suitable candidate for TVE. The failure of TVE occurred because the fistula point was distant from the SPS, and the high resistance impeded retrograde Onyx delivery toward the fistula point. Additionally, this SPS DAVF had 3 feeding sources; occlusion of merely the ECA inadequately reduced hemodynamic resistance, further hindering effective retrograde Onyx penetration. During retrograde Onyx casting, however, the SPV and cortical cerebellar vein became occluded due to low blood flow resistance, necessitating cessation of Onyx injection (Fig. 2C). Although the SPS DAVF was not penetrated by Onyx casting, the DAVF became no longer visible. However, this was an illusion of a DAVF cure. A complete cure was not achieved due to persistent fistula patency, as only the draining veins were occluded. The high-pressure feeding artery continued to perfuse the DAVF, ultimately leading to either SPS DAVF recurrence or occult cortical venous rupture post-EVT, resulting in SAH. Fortunately, the SAH was mild. Sedative administration and blood pressure control were maintained to promote spontaneous DAVF thrombosis, ultimately resulting in DAVF resolution at the 2-month DSA follow-up.

In Case 1 with a new postoperative SAH, potential vasospasm must be considered due to blood breakdown occurring 3-10 days post-SAH. Therefore, after 3 days of SAH, CT demonstrated SAH absorption, prompting discontinuation of blood pressure control. Concurrently, the rebleeding risk decreased due to spontaneous thrombosis of the DAVF. In Case 2, the patient exhibited left facial numbness as a complication of Onyx injection via the AMA. Anatomically, the recurrent branch of the AMA provides vascular supply to the trigeminal ganglion; its iatrogenic occlusion can lead to trigeminal nerve injury, manifesting as facial numbness [20]. Consequently, Onyx injection via the AMA warrants utmost caution.

Conclusion

For SPS DAVFs, when TAE alone cannot cure them, a combined transarterial/transvenous approach is valuable. After transarterial occlusion of the feeding artery, TVE can be performed. For non-sinus-type SPS DAVFs, TVE should be performed cautiously. Retrograde transvenous Onyx casting within the SPS may have difficulty penetrating the DAVF, even with the assistance of a dual-lumen mini-balloon catheter. Although occluding only the draining veins may provide a potential cure for the SPS DAVF, the risk of hemorrhagic complications must be considered. In contrast, for sinus-type SPS DAVFs, coiling the dilated SPS as the fistula point may be sufficient after occlusion of the feeding artery.

Limitation

This case report presents 2 SPS DAVFs treated with a combined transarterial/transvenous approach, providing clinically valuable insights. However, as a case report, these findings are inherently anecdotal, thereby limiting generalizability. Larger cohort studies are warranted to confirm these observations.

Author contributions

Conceptualization, Data curation, Formal analysis, Methodology, Project administration, Software, Supervision, Writing—original draft, Writing—review and editing: Jinlu Yu.

Data availability

No datasets were generated or analyzed during the current study.

Patient consent

Written informed consent was obtained from the patient and the patients involved for publication in this case report and any accompanying images.