Endoscopic endonasal transsphenoidal management of an indirect cavernous sinus dural arteriovenous fistula: a case report.

A 27-year-old nulliparous female presented with seven-month progression of right-sided pulsatile exophthalmos subsequent to minor head trauma (Fig. 1 A). Neuro-otological evaluation revealed objective pulsatile tinnitus synchronized with cardiac cycle on auscultation. The patient had been previously diagnosed with a right-sided CS-DAVF at a local hospital and had undergone embolization at another facility. However, during the procedure, challenges in identifying the inferior petrosal sinus, intracavernous sinus, and facial vein resulted in an unsuccessful embolization, prompting her referral to our hospital for further management. Fig. 1 The preoperative evaluation and surgical process in Case. A The timeline of management for the case. B Preoperative MRA of the head demonstrates early enhancement around the right meningeal region near the right internal carotid artery. C Preoperative right ICA angiography confirms the presence of a right CS-DAVF. D Lateral view of the right carotid artery following contrast injection reveals early filling of the inferior ophthalmic vein during the arterial phase. E Preoperative DSA indicates that the ascending pharyngeal artery is a feeder to the CS-DAVF. F Three-dimensional reconstruction of DSA demonstrated the anatomical structure of the cavernous sinus dural arteriovenous fistula and its spatial relationship with the cavernous sinus (asterisk). G A 4 F vascular sheath was placed into the right cavernous sinus through an endoscopic transdural incision. H The angiosheath was then manually supported and secured in place throughout the procedure. I A 4 French (4F) angiosheath was navigated and positioned within the right cavernous sinus for endovascular access. J Contrast injection through the angio-sheath in cavernous sinus demonstrates that the DAVF primarily drains via the inferior ophthalmic vein (arrow) and the inferior petrosal sinus (arrowhead). K The angiogram obtained after deployment of coils demonstrates subtotal occlusion of cavernous sinus with improved venous drainage. L , M Subsequent angiographic images obtained after Onyx embolization confirm complete occlusion of the right cavernous sinus and the DAVF, with a clearly defined embolic cast. N Three-dimensional reconstruction revealed complete occlusion of the right cavernous sinus and the associated dural arteriovenous fistula The preoperative evaluation and surgical process in Case. A The timeline of management for the case. B Preoperative MRA of the head demonstrates early enhancement around the right meningeal region near the right internal carotid artery. C Preoperative right ICA angiography confirms the presence of a right CS-DAVF. D Lateral view of the right carotid artery following contrast injection reveals early filling of the inferior ophthalmic vein during the arterial phase. E Preoperative DSA indicates that the ascending pharyngeal artery is a feeder to the CS-DAVF. F Three-dimensional reconstruction of DSA demonstrated the anatomical structure of the cavernous sinus dural arteriovenous fistula and its spatial relationship with the cavernous sinus (asterisk). G A 4 F vascular sheath was placed into the right cavernous sinus through an endoscopic transdural incision. H The angiosheath was then manually supported and secured in place throughout the procedure. I A 4 French (4F) angiosheath was navigated and positioned within the right cavernous sinus for endovascular access. J Contrast injection through the angio-sheath in cavernous sinus demonstrates that the DAVF primarily drains via the inferior ophthalmic vein (arrow) and the inferior petrosal sinus (arrowhead). K The angiogram obtained after deployment of coils demonstrates subtotal occlusion of cavernous sinus with improved venous drainage. L , M Subsequent angiographic images obtained after Onyx embolization confirm complete occlusion of the right cavernous sinus and the DAVF, with a clearly defined embolic cast. N Three-dimensional reconstruction revealed complete occlusion of the right cavernous sinus and the associated dural arteriovenous fistula The neurologically intact patient (GCS 15, MMSE 28/30) maintained therapeutic levels of first-line antitubercular therapy (isoniazid 5 mg/kg/d, rifampin 10 mg/kg/d, ethambutol 15 mg/kg/d) for ovarian tuberculosis. Preoperative magnetic resonance angiography (MRA) of the head revealed abnormal early enhancement of right cavernous sinus (Fig. 1 B). Digital subtraction angiography (DSA) further demonstrated early venous filling of the cavernous sinus, with subsequent reflux into the cortical veins following contrast injection into the right internal carotid artery (ICA). The CS-DAVF was primarily supplied by the right meningohypophyseal trunk of the right ICA (Fig. 1 C, D). Additionally, angiography of the right external carotid artery (ECA) revealed that the ascending pharyngeal artery contributed to the CS-DAVF (Fig. 1 E). The left meningohypophyseal trunk of the left ICA was also found to supply the fistula. Three-dimensional reconstruction of DSA demonstrated the fistula connection between meningeal artery and cavernous sinus (Fig. 1 F). This case involved an indirect dural cavernous-carotid fistula, a subtype characterized by low-flow shunting and multiple dural arterial feeders (Barrow type D). Since the lesion could not be accessed via conventional transvenous routes, a direct puncture of the cavernous sinus was considered to facilitate targeted embolization. Written informed consent was obtained from the patient and her family, and the procedure was performed under general anesthesia. Surgery was conducted in a hybrid operating room equipped with monoplane fluoroscopy and a neuroendoscopic system. The procedure began with access to the right femoral artery using a 6 F sheath, followed by the positioning of an angiographic catheter in the right internal carotid artery (ICA). Transnasal endoscopy was then employed to identify and expose the inner wall of the cavernous sinus. After the dural tissue of the cavernous sinus was incised, a 4 F diagnostic sheath was introduced without an introducer into the right cavernous sinus (Fig. 1 G). The angiosheath was subsequently stabilized by manual support and maintained securely in position throughout the procedure (Fig. 1 H). Subsequently, a microcatheter (Echelon 10, ev3) was advanced over a 0.014 microwire (Synchro 14, Stryker) into the cavernous sinus. Contrast injection via the microcatheter demonstrated anterograde venous drainage (Fig. 1 I), primarily into the inferior ophthalmic vein, with a small amount of contrast also draining through the inferior petrosal sinus (Fig. 1 J). The cavernous sinus cavity was initially occluded with an 18 × 50 mm Axium coil (eV3), achieving a loose occlusion. Additional coils, specifically a 5 × 20 mm coil, were subsequently deployed, further embolizing the cavernous sinus and reducing the flow rate (Fig. 1 K). Under fluoroscopic guidance, Onyx-18 (eV3) was slowly injected into the cavernous sinus, with a small portion of the embolic material extending into the superior ophthalmic vein. Following microcatheter angiography demonstrated a significant reduction in contrast flow rate (Fig. 1 I, J). Right internal carotid angiography confirmed the absence of blood flow into the right cavernous sinus during the early arterial phase (Fig. 1 L–N). After the gradual removal of the angiosheath from the cavernous sinus, hemostasis was achieved using absorbable gelatin sponge compression. The patient remained stable postoperatively, with mild third cranial nerve palsy. The patient was followed up at three months after embolization. A follow-up DSA revealed complete occlusion of CS-DVAF (Fig. 2 A-T). There is no residual arteriovenous shunting or recurrence. Fig. 2 Follow-up angiography was performed at 3 months after embolization. Cerebral angiography was performed at the 3-month follow-up at different stasis phrases. Contrast agent was selectively injected via right internal carotid artery ( A - D frontal view; E - H lateral view), right external carotid artery in frontal view ( I - L ), and left internal carotid artery ( M - P frontal view; Q - T lateral view), respectively Follow-up angiography was performed at 3 months after embolization. Cerebral angiography was performed at the 3-month follow-up at different stasis phrases. Contrast agent was selectively injected via right internal carotid artery ( A - D frontal view; E - H lateral view), right external carotid artery in frontal view ( I - L ), and left internal carotid artery ( M - P frontal view; Q - T lateral view), respectively

In selected patients with indirect CS-DAVFs complicated by inferior petrosal sinus occlusion, embolization may be successfully achieved through direct puncture of the cavernous sinus under endoscopic endonasal guidance using coils and Onyx. Although detailed anatomical knowledge of the cavernous sinus via the transsphenoidal approach has been well described, successful application of this technique requires close collaboration and substantial experience in endoscopic skull base surgery. This case suggests that the endonasal approach may serve as an alternative option for carefully selected indirect CS-dAVFs when conventional transvenous or transarterial routes are not feasible or carry excessive risk. However, its efficacy and safety need to be validated in larger series, and its applicability to other types of CS-dAVFs remains to be determined.

DAVFs are pathological shunts between dural arteries and the dural venous sinus, meningeal veins, or cortical veins [ 7 ]. The clinical manifestations of DAVFs are closely associated with their venous drainage patterns. As the result, CS-DAVF could present ophthalmological signs such as proptosis and intolerable diplopia when venous drainage is directed anteriorly into the superior and inferior ophthalmic veins [ 3 ]. When venous drainage occurs inferiorly into the inferior petrosal sinus, patients may experience tinnitus. While, DAVFs with cortical venous drainage might present with headaches and significant risk of hemorrhage [ 8 ]. Currently, endovascular embolization is the primary treatment modality for DAVF, aiming to occlude the pathological arteriovenous communication, reduce venous hypertension, and alleviate associated clinical symptoms [ 15 ]. Based on the angioarchitecture and hemodynamic characteristics of the lesion, CS-DAVFs are broadly classified into direct and indirect types [ 4 ]. Indirect CS-DAVFs typically exhibit low-flow shunting with multiple dural arterial feeders; therefore, transvenous embolization is generally regarded as a safer and more effective treatment strategy than transarterial approaches [ 1 ]. Given that the majority of CS-DAVFs drain through the inferior petrosal sinus, this route frequently serves as the primary access for endovascular intervention [ 13 ]. Furthermore, patients with ipsilateral inferior petrosal sinus occlusion are more likely to exhibit ophthalmic symptoms [ 17 ]. For patients with venous drainage via the superior ophthalmic vein, alternative techniques such as direct puncture of the superior ophthalmic vein or trans-ophthalmic venous access via the femoral vein may be considered. In the present case, preoperative DSA demonstrated that the primary venous drainage occurred through the inferior ophthalmic vein, and therefore alternative treatment strategies were required to achieve complete occlusion of the fistula. In this context, the present case suggests that, in CS-DAVFs where conventional transarterial access or standard transvenous routes—such as the inferior petrosal sinus or the superior ophthalmic vein—are inaccessible or unsuccessful, direct puncture and embolization of the cavernous sinus may represent a feasible alternative strategy. [ 2 ]. Previously, Trivelato et al. reported a series of eight patients with CS-DAVF treated by direct transorbital puncture of the cavernous sinus under fluoroscopic guidance, achieving complete angiographic occlusion in seven cases. However, procedure-related complications were observed, including one case of superior ophthalmic vein thrombosis and one case of internal carotid artery injury [ 18 ]. Because fluoroscopy-guided transorbital techniques do not allow direct visualization of intra-orbital anatomy, they carry inherent risks, such as eyeball perforation, optic nerve injury, internal carotid artery laceration, and cranial nerve III, IV, and VI injuries [ 12 ]. More recently, Hains et al. reported a case of CS-DAVF successfully treated via an endoscopic-assisted transorbital approach, highlighting the potential advantages of enhanced visualization during cavernous sinus access [ 9 ]. Building on these advances, our case further supports the endonasal endoscopic approach as a viable and effective management strategy for selected CS-DAVFs. This approach enables direct and controlled access to the cavernous sinus while providing real-time visualization of critical anatomical structures, thereby potentially reducing the risk of neurovascular injury. Although endovascular therapy remains the standard of care for CS-DAVF, the endonasal approach offers a distinct alternative in carefully selected patients, particularly when conventional arterial or venous routes are not feasible. Compared with traditional open surgical methods, this minimally invasive technique may be associated with lower morbidity while maintaining high rates of fistula occlusion [ 6 ]. Our report underscores the importance of individualized anatomical assessment in treatment planning and contributes additional evidence to the limited literature on alternative access strategies for this rare and challenging condition. One possible explanation for these clinical observations is that the endonasal approach may allow for improved visualization and more direct access to the fistula, thereby potentially facilitating symptom relief and overall patient recovery [ 14 ]. In our case, the endoscopic transnasal approach provided direct visualization of the cavernous sinus and enabled precise localization for sheath placement. Nevertheless, this technique carries inherent risks that warrant careful consideration. Accurate identification of the puncture site is essential, as misinterpretation of the cavernous sinus anatomy may lead to inadvertent injury of the ICA, which can result in massive intraoperative hemorrhage and may predispose patients to pseudoaneurysm formation, complicating subsequent management of DVAF. Moreover, given the close anatomical relationship between the ICA and the cavernous sinus, even slight deviations in the puncture trajectory may substantially increase the risk of subarachnoid hemorrhage. Similar concerns have been reported in procedures involving superior ophthalmic vein cannulation, where ICA injury has resulted in severe bleeding [ 10 ]. To mitigate these risks, the angiosheath was carefully introduced, the dilator withdrawn under direct control, and the sheath stabilized manually to prevent unintended displacement. If arterial bleeding is encountered upon removal of the dilator, it should be reinserted immediately, followed by endoscopic compression of the suspected ICA entry point before withdrawing the angiosheath to achieve hemostasis. Subsequent angiography is necessary to evaluate for potential pseudoaneurysm formation and to guide timely intervention if needed. These considerations underscore the critical importance of selecting an anatomically appropriate puncture site within the cavernous sinus to minimize the likelihood of vascular injury and its associated complications. Despite these precautions, transient cranial nerve dysfunction developed in our patient. Given that the cavernous sinus contains cranial nerves III, IV, and VI, along with the ophthalmic division of the trigeminal nerve [ 19 ], manipulation within this confined space may elevate intracavernous pressure or induce traction on these structures. The gradual improvement observed during follow-up suggests that such injuries are largely reversible. Nonetheless, this case emphasizes the importance of minimizing intracavernous tension and maintaining meticulous control of sheath position to reduce the risk of postoperative neurological deficits and to support optimal recovery [ 16 ]. Although this report provides valuable technical insights, it is based on a single case of an indirect CS-DAVF, and therefore its findings must be interpreted with caution. Our experience suggests that the endonasal approach may represent a feasible alternative treatment option for carefully selected indirect CS-DAVFs, particularly when conventional transvenous or transarterial routes are associated with substantial risks or are anatomically unfavorable. This case highlights a potentially useful strategy that may expand the therapeutic armamentarium for indirect CS-DAVFs under specific circumstances; however, the applicability of this technique to direct, high-flow CS-DAVFs remains unknown and cannot be inferred from the present report. Further clinical experience and larger studies are required to evaluate the reproducibility, efficacy, and safety of this approach and to better define its role and limitations in the management of CS-DAVFs.

Cavernous sinus dural arteriovenous fistula (CS-DAVF) is a rare but clinically significant vascular condition characterized by abnormal connections between the arterial and venous systems within the cavernous sinus. An indirect CS-DAVF is the lesion supplied by multiple dural arterial branches originating from the internal and/or external carotid arteries, which shunt blood into the cavernous sinus through the dural wall. Although most patients with indirect CS-DAVF can be treated through the inferior petrosal sinus or superior ophthalmic vein through venous access [ 5 ], for a small number of patients with inferior petrosal sinus occlusion or insufficient drainage of the superior ophthalmic vein, conventional treatment becomes difficult [ 11 ]. In this report, we present a rare case of indirect CS-DAVF treated with complete endovascular embolization after the establishment of transcavernous sinus vascular access with the assistance of endoscopic endonasal transsphenoidal (EET) approach.