Fluid-Filled Dehiscences in the Anterior Cranial Fossa Floor: A Magnetic Resonance Imaging Study.

OBJECTIVE: To date, only limited information regarding the anterior cranial fossa floor (AFF) and the appearance of sites of dehiscence and potential channels has been available. We aimed to evaluate this region with thin section magnetic resonance imaging (MRI). PATIENTS AND METHODS: A total of 65 patients underwent thin-sliced coronal T2-weighted MRI. The AFF was divided into 3 parts for analysis: the anterior, middle, and posterior. RESULTS: Dehiscences were identified in 84.6% of 65 patients with apparently transmitting channels. In 49.2% of the patients, the dehiscences were located in the anterior part, whereas they were located in the middle and posterior parts in 52.3% and 12.3%, respectively. The morphology and number of these dehiscences were highly variable. In 12.3%, channels in the dehiscences were distributed extradural. Statistically, dehiscences were more frequently identified on the left side in any part of the AFF. CONCLUSIONS: With thin-sliced, coronal T2-weighted MRI, dehiscences were frequently identified in the anterior two-thirds of the AFF. Further study is warranted to determine the role of AFF channels and dehiscences, including possibly for cerebrospinal fluid drainage.

Recurrent epistaxis due to cribriform plate dural arteriovenous fistula: are they related? Should the treatment be from venous, pial or arterial side?

PURPOSE: Dural arteriovenous fistula (DAVF) of the anterior cranial fossa with cortical venous reflux is an aggressive neurovascular entity with a high rate of intracranial bleeding. Only two cases of anterior cranial fossa DAVF presenting with epistaxis alone have been reported. Endovascular approaches have emerged as the primary and safer treatment modality for most DAVFs. Certain fistulas are better treated with open surgical approaches and disconnection. CASE DESCRIPTION: A 55 years old male presented with the history of multiple episodes of severe epistaxis. Cerebral angiography revealed an anterior cranial fossa DAVF of the cribriform plate with cortical venous reflux and a venous varix. The patient was successfully managed with a bifrontal craniotomy and disconnection from the arterial side. CONCLUSION: Atypical or severe epistaxis may arise from a DAVF. Surgical arterial disconnection my be a curative treatment option.

Anterior cranial fossa dural arteriovenous fistula: Transarterial embolization from the ophthalmic artery as first-line treatment.

OBJECTIVE: To retrospectively review the outcome of patients with dural arteriovenous fistula of the anterior cranial fossa (afDAVF) treated by transarterial embolization. MATERIAL AND METHODS: Six consecutive patients were referred to our hospital for afDAVF treatment. After a multidisciplinary discussion, they underwent endovascular embolization with Onyx injection through the ophthalmic artery. Their clinical presentation, management and outcomes were retrospectively assessed. RESULTS: All interventions were performed with the liquid embolic agent Onyx through the transarterial route from the ophthalmic artery to access the fistulous point. All patients showed a good outcome with complete afDAVF obliteration. CONCLUSION: This study demonstrates that afDAVFs can be safely and completely obliterated by transarterial embolization via the ophthalmic artery.

Angiographic study of the transdural collaterals at the anterior cranial fossa in patients with Moyamoya disease.

Unlike its parietal, temporal, and occipital counterparts, the frontal lobe has a broad basal surface directly facing the anterior cranial fossa dura mater which could permit establishment of transdural collaterals (TDCs) with the frontal lobe. Studies on the TDCs from the anterior cranial fossa in moyamoya disease (MMD) are scarce and inadequately investigated. A retrospective study of 100 hemispheres in 50 patients who were diagnosed with MMD by catheter angiography between January 2015 and June 2019 was performed in our institution. TDCs through the anterior ethmoid artery (AEA) or posterior ethmoid artery (PEA) were divided into 3 types respectively based on their respective angioarchitecture. Furthermore, we also studied TDCs to the temporal, parietal, and occipital lobes and collaterals from the posterior circulation to the territory of the anterior cerebral artery. TDCs through the AEA and PEA were identified in 89 (89/100, 89%) and 73 (73/100, 73%) of the hemispheres. The vascularization state of the frontal lobe was good in 89 (89/100, 89%) hemispheres. Rete mirabile and TDCs through the PEA were statistically different among patients with different Suzuki stages. No statistical difference was noted in TDCs through the AEA, frontal TDCs from other sources, and the vascularization state of the frontal lobe with regard to different Suzuki stages. TDCs through the AEA and PEA at the anterior cranial fossa play a very important role in compensating the ischemic frontal lobe. The frontal lobe could be well compensated in most of the patients with TDCs at the anterior cranial fossa.

Evaluation of the Relationship Between Olfactory Fossa Measurements and Nasal Septum Deviation for Endoscopic Sinus Surgery.

INTRODUCTION: Endoscopic sinus surgeries (ESS) are frequently used in the treatment of optic nerve decompression, other intracranial lesions and sinonasal pathologies. The olfactory fossa can be localized on different levels in relation to the anterior cranial fossa. The aim of the present study was to evaluate the depth and width of the olfactory fossa (OF) in relation to nasal septum deviation (NSD). METHODS: A total of 225 patient (141 female and 84 male, age range between 15 to 56 years) of cone beam computed tomography (CBCT) data was used in this study. NSD, OF width, OF depth were measured. OF depth which was grouped according to the Keros classification as Type I, II, and III was calculated. All measurements were performed bilaterally except for NSD. RESULTS: In the right and left OF depth were found Keros Type I 32 (14.2%) and 30 (13.3%), Keros Type II 171 (76%) and 167 (74.2%), and Keros Type III 22 (9.8%) and 28 (12.4%) respectively. There was no statistically significant found between OF depth and NSD (P > 0.05). The mean angle of the NSD in men and women were 4.36 ±â€Š4.69 in women 4.11 ±â€Š4.36, respectively. The mean width of the right OF was 2.50 ±â€Š0.64 mm and 2.58 ±â€Š0.72 mm for the left side and there was no statistically significant association between OF width - NSD and OF width - OF depth (P > 0.05). CONCLUSION: The anatomy of the OF should be well established before surgical intervention increase of the length of the lateral lamella is also increases the risk of developing complications such as cerebral damage, hemorrhage, and cerebrospinal fluid fistula during endoscopic sinus surgery. Although there is no significant difference between OF measurement and NSD, with three-dimensional imaging detailed research is required before endoscopic sinus surgical operations.

[A Case of Anterior Cranial Fossa Dural Arteriovenous Fistula Involving Uncontrolled Seizures Diagnosed Based on Characteristic Findings on Arterial Spin-labeling Imaging].

We report a case of anterior cranial fossa dural arteriovenous fistula(ACF-DAVF)in a patient whose diagnosis was made according to characteristic findings on arterial spin labeling(ASL)MRI. CASE:A 68-year-old man was admitted to our hospital because of intractable epilepsy. Based on the initial MRI findings, an initial diagnosis of limbic encephalitis was made. Steroids and anticonvulsant drugs were administered;however, the seizures could not be controlled. A second MRI with ASL revealed abnormal vessel signals in the base segments of the left frontal and temporal lobes toward the basal vein of Rosenthal. Digital subtraction angiography(DSA)revealed an arteriovenous shunt in the left anterior cranial fossa, which drained toward the medial side of the left temporal lobe. A diagnosis of ACF-DAVF with status epilepticus was made, and the main drainer was cauterized. After the surgical procedure, the epilepsy was controlled with antiepileptic drugs, and postoperative MRI revealed obliteration of ACF-DAVF, disappearance of the high-intensity area on FLAIR sequences, and disappearance of the high-intensity signal area on ASL.

Cranial Fossa Volume in Differing Subtypes of Apert Syndrome.

BACKGROUND: Based on an established classification system of Apert syndrome subtypes, detailed regional morphology and volume analysis may be useful to provide additional clarification to individual Apert cranial structure characteristics, and treatment planning. METHODS: Computed tomography scans of 32 unoperated Apert syndrome and 50 controls were included and subgrouped as: type I, bilateral coronal synostosis; type II, pansynostosis; type III, perpendicular combination synostosis. Three-dimensional analysis of craniometric points was used to define structural components using Materialise Mimics and 3-Matics software. RESULTS: Occipitofrontal circumference of all subtypes of Apert syndrome patients is normal. Intracranial volumes of types I and II were normal, but type III was 20% greater than controls. Middle cranial fossa volume was increased in all 3 types, with the greatest increase in type II (86%). Type II developed a 69% increase in anterior cranial fossa volume, whereas type III had 39% greater posterior cranial fossa volume. Increased cranial fossa depth contributed most to above increased volume. The anteroposterior lengths of middle and posterior cranial fossae were reduced in type I (15% and 17%, respectively). However, only the anterior cranial fossa was significantly shortened in type III. CONCLUSIONS: Occipitofrontal circumference and overall intracranial volume is not always consistent in individual subunits of Apert syndrome. Detailed and segmental anterior, middle, and posterior cranial fossae volumes and morphology should be analyzed to see what impact this may have related to surgical planning.

Endovascular and surgical approaches of ethmoidal dural fistulas: a multicenter experience and a literature review.

Ethmoidal dural arteriovenous fistulae are rare vascular malformations associated with a high risk of bleeding. We present a multicenter contemporary series of patients treated with microsurgical and endovascular techniques. Sixteen consecutive patients were evaluated and/or treated between 2008 and 2015 at four centers with large experience in the endovascular and surgical treatment of cerebrovascular diseases. We analyzed demographic and clinical data, risk factors for dural fistulas, treatment type, peri- and post-operative morbidity, clinical and radiological outcomes, rates of occlusion, and long-term neurological outcome. Sixteen patients (81 % men, mean age of 58 years) with ethmoidal dural fistulas were included in the analysis. Seven patients had suffered an intracranial hemorrhage; the remaining presenting with neurological signs and symptoms or the fistula was an incidental finding. Three patients were managed conservatively. Among patients who underwent intervention (n = 13), 46.1 % were treated with endovascular therapy and 53.9 % were treated surgically. Complete angiographic obliteration was achieved in 100 % immediately after treatment and at last follow-up evaluation. All patients experienced a favorable neurological recovery (mRS 0-2) at the last follow-up visit (12 months). Ethmoidal dural AVFs are found mostly in male patients. Nowadays, due to wider use of non-invasive imaging, AVFs are discovered with increasing frequency in patients with minimal or no symptoms. Traditionally, these fistulas were considered "surgical." However, in the modern endovascular era, selected patients can be effectively and safely treated with embolization although surgical ligation continues to have an important role in their management.

[A Case of Dural Arteriovenous Fistula in the Anterior Cranial Fossa that Developed Remote from the Craniotomy Site after Surgery].

Dural arteriovenous fistula(dAVF)is relatively rare, and its etiology remains uncertain. Generally, dAVF is thought to be acquired and has been reported to develop secondary to sinus thrombosis, head injury, infection, and surgery. We report a rare case of dAVF in the anterior cranial fossa that developed remote from the craniotomy site after surgery. A 52-year-old man underwent surgery for hypertensive intracerebral hemorrhage 4 years prior. Perioperative imaging modalities demonstrated no abnormal vascular malformation except for an un-ruptured anterior communicating artery aneurysm. Four years later, follow-up magnetic resonance angiography showed abnormal vascular malformation in the anterior cranial fossa, and cerebral angiography demonstrated dAVF. dAVF and aneurysm were successfully treated. Possible formation of a dAVF should be considered after craniotomy.

[The trans-eyebrow supraorbital approach for removal of anterior cranial fossa and suprasellar meningiomas]. / Supraorbital'nyi chrezbrovnyi dostup dlia udaleniia meningiom perednei cherepnoi iamki i supraselliarnoi oblasti.

Over the past two decades, improvements in surgical tools, navigation systems, and endoscopic techniques have resulted in the widespread use of keyhole surgery for a wide range of skull base tumors. Currently, the trans-eyebrow supraorbital approach is being increasingly used in surgery for anterior cranial fossa and parasellar tumors. MATERIAL AND METHODS: The study included 7 patients who underwent surgery for meningioma using the trans-eyebrow supraorbital approach at the Burdenko Neurosurgical Institute in the period between 2013 and 2017. The age of patients ranged from 51 to 75 years (median, 60 years); there were 5 females and 2 males. The maximum diameter of resected tumors ranged from 20 to 60 mm (median 40 mm). RESULTS: Total resection of the tumor was achieved in all 7 cases, which was confirmed by postoperative MRI control. All 7 patients had a good cosmetic result. In 1 case, there was postoperative cerebrospinal fluid rhinorrhea due to incomplete closure of the frontal sinus, which required the patient to be re-operated. None of 7 cases was associated with injury to the main vessels or cavernous sinus. CONCLUSION: Supraorbital trans-eyebrow craniotomy provides a minimally invasive approach for removing most anterior cranial fossa base and suprasellar tumors. The advantages of keyhole surgery, in comparison with traditional craniotomies, are minimal complications associated with the approach.

Evaluation of Optic Canal and Surrounding Structures Using Cone Beam Computed Tomography: Considerations for Maxillofacial Surgery.

The optic canal connects the anterior cranial fossa and the orbit and maintains the optic nerve and the ophthalmic artery. Within the extent of the surgical approach of the region, risk of iatrogenic injury of the neural and vascular structures increases. The aim of this retrospective morphometric study is to investigate the radiological anatomy of orbita, optic canal, and its surrounding using cone beam computed tomography (CBCT) scans in a group of Turkish population.Cone beam computed tomography images of a total of 182 patients were evaluated by 2 observers. Anatomical parameters regarding optic canal and orbita were measured for all patients from axial, sagittal, and three-dimensional reconstructed images. To assess intraobserver reliability, the Wilcoxon matched-pairs test was used. Pearson χ test and Student t test were performed for statistical analysis of differences, sex, localization, and measurements (P < 0.05).Repeated CBCT evaluation and measurements indicated no significant inter and intra-observer difference were found (P > 0.05). The orbita width and height were larger for the males than females (P < 0.05). No significant difference was observed for optic canal shape, dimensions of infraorbital foramen (IOF) and supraorbital foramen (SOF), SOF-midline distance, and SOF-IOF distance according to sex and location (P > 0.05). Examination CBCT scans revealed that the shape of the optic canal was 70% funnel and 28% Hourglass shape, 2% amorph type round.These results provide detailed knowledge of the anatomical characteristics in the orbital area which may be of assistance for surgeons preoperatively. Cone beam computed tomography scans can be an alternative modality for multislice computed tomography with submillimeter resolution and lower dose in preoperative imaging of the orbit.

Transarterial Embolization of Anterior Cranial Fossa Dural AVFs as a First-Line Approach: A Single-Center Study.

BACKGROUND AND PURPOSE: Endovascular treatment has been increasingly used for anterior cranial fossa dural AVFs. Evidence on the safety and efficacy of different endovascular treatment strategies is limited. We report clinical and angiographic outcomes of patients with anterior cranial fossa dural AVFs who underwent treatment using transarterial embolization with n-BCA as a first-line approach. MATERIALS AND METHODS: Consecutive patients undergoing treatment for anterior cranial fossa dural AVFs at the Amsterdam University Medical Centers between 2010 and 2023 were retrospectively included. Transarterial embolization was used as a first-line approach, while transvenous treatment and surgery were used in cases of unsuccessful transarterial embolization. Treatment was evaluated on the basis of the angiographic cure rate, procedural complications, and clinical outcome. RESULTS: Fourteen patients were included with 15 anterior cranial fossa dural AVFs. All patients underwent primary endovascular treatment (12 transarterial, 1 transvenous, and 1 combined). Complete occlusion using only transarterial embolization was reached in 69% of patients (9/13), while the overall complete occlusion by endovascular treatment was reached in 79% of patients (11/14). Navigation and embolization were performed through the ophthalmic artery in 13 patients, with no procedural complications. Visual acuity was preserved in all patients. Three patients underwent an operation after failed endovascular treatment. All patients had complete anterior cranial fossa dural AVF occlusion at follow-up. CONCLUSIONS: Treatment of anterior cranial fossa dural AVFs using transarterial embolization with n-BCA as a first-line approach is a safe and feasible first-line treatment strategy. No visual complications due to embolization through the ophthalmic artery occurred in this study.

Sinonasal adenocarcinoma presented as a giant anterior cranial fossa mass: a case report and review of the literature.

BACKGROUND: Intestinal adenocarcinoma accounts for less than 0.1-4% of all malignancies in the region. It is common among woodworkers and leather workers. Sinonasal adenocarcinoma usually arises from the ethmoid sinus (40%) or nasal cavity (25%). Extension to nearby structures is common, but intracranial spread is very rare. These tumors are usually treated with surgery, with a reported 5-year survival rate of 59% to 80%. CASE PRESENTATION: This is a 60-year-old Black African male patient who presented with globalized headache, nasal obstruction with snoring during sleep, anosmia, change in mentation, sometimes agitation and left-side visual loss of one-year duration with worsening his above symptoms over the last one month. He couldn't smell soap bilaterally; in his left eye he could see only hand movement at nearly 30 cm. On brain magnetic resonance imaging, there was a T1 hypo- and T2 hyper-intense anterior cranial fossa mass arising from the left ethmoid sinuses and sphenoid sinuses and compressing the left optic structures, and brain computed tomography demonstrated heterogeneous hypo- to isodense mass. Complete tumor excision achieved and discharged with significant improvement and linked to oncology unit for radiotherapy. CONCLUSION: The management of these patients is multidisciplinary, involving neurosurgeons, otolaryngologists, oncologists, and maxillofacial surgeons. Surgical resection is the main treatment strategy, followed by radiotherapy, particularly intensity-modulated therapy. Chemotherapy is used in highly advanced, metastatic, and unresectable tumors.

Bacteriology of normal frontal sinuses.

PURPOSE: The aim of this cross-sectional trial was to identify the bacterial flora and to quantify the level of bacterial presence in healthy adult frontal sinus cavities. MATERIALS AND METHODS: Ninety five consecutive patients undergoing craniotomy of the anterior cranial fossa were enrolled. All patients were evaluated preoperatively by a sino-nasal questionnaire, nasal endoscopy and CT scan. Exclusion criteria were patients with sinus tumours, presenting a cold in the past 8 weeks, having signs or symptoms suggestive of sinus disease, history suggestive of allergic rhinitis and/or asthma, having undergone hospitalization or an outpatient clinic visit within the past 12 months, patients with known systemic disease, having previous sinus or nose surgery, history of trauma of the sino-nasal region, or having used systemic antibiotics, steroids, or nasal spray in the past 8 weeks. Lavages were obtained from frontal sinuses before craniotomy through trephination of the anterior wall. The sinus was irrigated with sterile saline followed by aspiration. Specimens were inoculated for aerobic and anaerobic organisms. RESULTS: After applying the exclusion criteria, 42 patients (84 sinuses) were finally included in the study. Bacterial organisms were recovered in 12 of 84 (14.28%) sinuses. However, 85.72% of the sinuses were found to be sterile. Bacteria recovered included three different coagulase-negative staphylococci, one Citrobacter diversus and two Micrococcus spp. No anaerobic organism was isolated. CONCLUSIONS: This study demonstrated that the majority of frontal sinuses of asymptomatic adults with normal CT and endoscopic appearance are sterile.

The relationship between pneumatized middle turbinate and the anterior ethmoid roof dimensions: a radiologic study.

The development of pneumatized middle turbinate may affect anterior ethmoid roof formation. The aim of this study was to investigate the relationship between the pneumatized middle turbinate and the dimensions of the anterior skull base structures using computed tomography scans. The coronal reconstructed images of the computed tomography scans were evaluated retrospectively. The lateral and medial ethmoid roof points, the width of the cribriform plate (CP), and the anterior ethmoid roof were identified at the first coronal cut, which was determined by the infraorbital nerve. The pneumatized middle turbinates were measured on the axial, vertical, and sagittal planes. The images of 101 patients were evaluated. The mean axial diameters of the pneumatized middle turbinate on the right and left sides were between 6.93 and 4.95 mm, respectively. The correlation between the axial diameters of the pneumatized middle turbinate and the width of the anterior ethmoid roof (termed AER width) was significant for both sides and gender (p < 0.05). There was a higher correlation on the right side where the pneumatized middle turbinate was observed more frequently (r = 0.357). The relationship between CP width and the diameters of the pneumatized middle turbinate was not significant (p > 0.05) for both sides. Iatrogenic lesions of the skull base occur predominantly in the lateral lamella of the CP. The risk of this complication may decrease with increasing of the AER width. Pneumatized middle turbinate may cause an increase in the width of the anterior ethmoid roof and provide more reliable endoscopic intervention of the anterior skull base and frontal sinus.

[Imaging quality and dosage in ENT--what do we really need?]. / Dosisreduktion unter Betrachtung der erforderlichen Bildqualität--Wie viel Dosis braucht ein Bild?

BACKGROUND: Today, imaging of nose, paranasal sinuses and temporal bone by CT is standard in preoperative diagnostics. The need of reduction of applied dosage leads to the necessity of research in necessary imaging quality. Therefore this paper deals with new developed anatomical checklists and the analysis of imaging quality on anterior and lateral skull base. MATERIAL AND METHODS: With 3 human complete heads over 400 examinations were performed on one cone beam CT device under varying x-ray-tube adjustments. 31 anatomic parameters were evaluated (Excellent, well, poor, not evaluable) for every data set. A summation score was built for every examination. RESULTS: As well for paranasal sinuses as for temporal bone a constant excellent imaging quality could be seen in high dosages. Certainly, in low dosages a reduction of imaging quality was detected. The optimal range (all parameters visualized well as average) could be evaluated for paranasal sinuses between 2,0 and 3,0 mGy and between 3,0 and 4,0 mGy for temporal bone. So, a reduction of 70-80% in comparison to highest adjustments of today is possible and realistic. In comparison to standard protocols, a reduction of about 50% can be reached. CONCLUSION: The possibility of dose reduction by discussion of the necessary imaging quality from clinical point of view could be shown.

Natural history, angiographic presentation and outcomes of anterior cranial fossa dural arteriovenous fistulas.

BACKGROUND: Anterior cranial fossa dural arteriovenous fistulas (ACF-dAVFs) are aggressive vascular lesions. The pattern of venous drainage is the most important determinant of symptoms. Due to the absence of a venous sinus in the anterior cranial fossa, most ACF-dAVFs have some degree of drainage through small cortical veins. We describe the natural history, angiographic presentation and outcomes of the largest cohort of ACF-dAVFs. METHODS: The CONDOR consortium includes data from 12 international centers. Patients included in the study were diagnosed with an arteriovenous fistula between 1990-2017. ACF-dAVFs were selected from a cohort of 1077 arteriovenous fistulas. The presentation, angioarchitecture and treatment outcomes of ACF-dAVF were extracted and analyzed. RESULTS: 60 ACF-dAVFs were included in the analysis. Most ACF-dAVFs were symptomatic (38/60, 63%). The most common symptomatic presentation was intracranial hemorrhage (22/38, 57%). Most ACF-dAVFs drained through cortical veins (85%, 51/60), which in most instances drained into the superior sagittal sinus (63%, 32/51). The presence of cortical venous drainage predicted symptomatic presentation (OR 9.4, CI 1.98 to 69.1, p=0.01). Microsurgery was the most effective modality of treatment. 56% (19/34) of symptomatic patients who were treated had complete resolution of symptoms. Improvement of symptoms was not observed in untreated symptomatic ACF-dAVFs. CONCLUSION: Most ACF-dAVFs have a symptomatic presentation. Drainage through cortical veins is a key angiographic feature of ACF-dAVFs that accounts for their malignant course. Microsurgery is the most effective treatment. Due to the high risk of bleeding, closure of ACF-dAVFs is indicated regardless of presentation.

Endoscope-Controlled High Frontal Approach for Dural Arteriovenous Fistula in Anterior Cranial Fossa.

BACKGROUND: Currently, surgical obliterations are a mainstay for treating dural arteriovenous fistula (DAVF) in the anterior cranial fossa (ACF), which has high risks of hemorrhage and functional disorder. By introducing an endoscope into a high frontal approach and utilizing its advantages, we attempted to establish it as a new surgical procedure that eliminates the drawbacks of various approaches that have been used to date. METHODS: By using 30 clinical datasets of venous-phase head computed tomography angiogram, measurements and comparisons on a 3-dimensional workstation were performed to identify the appropriate positioning of keyhole craniotomy for endoscope-controlled high frontal approach (EHFA). Based on these data, a cadaver-based surgery was simulated to verify the feasibility of EHFA and develop an efficient procedure. RESULTS: In EHFA, though raising the position of the keyhole craniotomy made the operative field deeper, significant advantages were obtained in the angle between the operative axis and the medial-anterior cranial base and the amount of bone removal required at the anterior edge of craniotomy. Minimally invasive EHFA, performed through a keyhole craniotomy without opening the frontal sinus, proved to be feasible on 10 sides of 5 cadaver heads. Moreover, 3 patients with DAVF in ACF were successfully treated by clipping the fistula via EHFA. CONCLUSIONS: EHFA, which provided a direct corridor to the medial ACF at the level of the foramen cecum and crista galli and the minimum necessary operative field, was found to be a suitable procedure for clipping the fistula of DAVF in ACF.