Successful treatment of rapid onset Foix-Alajouanine syndrome following hyperselective endovascular embolization of thoracic dural arteriovenous fistula: Case report, technical note and literature review
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Abstract
Foix-Alajouanine syndrome is an extremely rare yet important differential diagnosis for subacute lower limb weakness in middle-aged to elderly adults. Current understanding of the pathophysiology of this disease, along with recent publications on successful endovascular interventions, has shifted the perspective and clinical approach for its management. Nonetheless, neurosurgical pathways for clinical treatment are still preferred over endovascular embolization.
Here, we present the case of a 63-year-old male who developed a rapidly progressing thoracic medullary syndrome over a 6-month period, compromising motor function, sphincter control, and sensory function in the lower extremities. The patient was diagnosed with venous congestive myelopathy secondary to a dural arteriovenous fistula and underwent endovascular embolization using hyper-selective catheterization. Over an 8-month period, the patient experienced successful recovery of both motor and sensory functions. This case supports the use of minimally invasive techniques for the treatment of dural arteriovenous fistulae with spinal involvement.
INTRODUCTION
Spinal Dural Arteriovenous Fistulae (dAVFs) are the most common type of spinal arteriovenous malformation [1]. Although most dAVFs tend to present with lower limb weakness and general symptoms, only a few cases lead to progressive neurological deterioration, resulting in Foix-Alajouanine syndrome (F-A syndrome) [2].
Foix-Alajouanine syndrome remains one of the most feared yet uncommon complications of spinal dural arteriovenous fistulae. In most cases, the clinical syndrome affects the thoracic to lumbar spine segments, causing weakness, paraplegia, hypoesthesia, saddle anesthesia, sphincter incontinence, and retention [4]. Given the clinical characteristics of this syndrome, several other syndromes and diseases should be considered in the differential diagnosis, including spinal cord infarction, demyelinating diseases [5], and other medullary syndromes [6].
The pathophysiology of F-A syndrome involves hemodynamic stressors that can lead to thrombosis, stasis, or infection in the dural vasculature. Its treatment depends on various factors, such as the anatomical origin of the feeding arteries and the size and structure of the malformation, weighing the benefits and risks of different treatment approaches [4,7,8]. The severity of neurological symptoms underscores the importance of early intervention and the potential for higher success rates in halting or reversing clinical symptoms if treated in a timely manner [6].
CASE DESCRIPTION
A 63-year-old male was referred to our tertiary care center from the neurosurgery department of a public general hospital for evaluation of a suspected vascular abnormality. The patient initially experienced a sudden episode of lower extremity weakness that caused a fall and left him unable to stand. Over the next three months, the patient experienced a progressive loss of sphincter function and worsening lower extremity weakness, eventually resulting in complete paraplegia. During the initial consultation, he was assessed as a 4 on the modified Rankin Scale (mRS) and an 8 on the Aminoff-Logue Score.
Initial diagnostic imaging included both computed tomography angiography (CTA) and magnetic resonance imaging (MRI). A contrast computed tomography (CT) angiogram following the administration of 10 mg of Isosorbide revealed perimedullary venous dilation at the T6 and T7 segments (Fig. 1A). Additionally, a T2-weighted sequence from the MRI demonstrated medullary edema and prominent flow voids in the perimedullary space (Fig. 1B), which strongly suggested a dAVF. After further consultation, a preliminary clinical diagnosis of an incomplete medullary syndrome originating at the T10 segment and a probable spinal dural arteriovenous fistula was made.
(A) Angiotomography of the dorsal column in lateral and anteroposterior projections after the ingestion of 10 mg of isosorbide, showing the fistula and dilation of the perimedullary veins at the level of T6-T7. (B) Pre-embolization T2-weighted magnetic resonance sequences in a sagittal view, demonstrating medullary edema and prominent flow voids in the perimedullary intradural space.
Digital Subtraction Angiography (DSA) confirmed the presence of a spinal dural arteriovenous fistula at the T6 level involving the right radicular artery, which drained into the radicular vein. The perimedullary venous drainage was descending, with venous dilation observed in the spinal vein from the mid and posterior portions of the spinal canal. Following the diagnostic angiogram, the patient was diagnosed with Foix-Alajouanine syndrome (F-A syndrome) caused by a thoracic dAVF and was scheduled for endovascular embolization.
The procedure was conducted under anesthetic monitoring with the patient in the dorsal decubitus position. After asepsis and antisepsis of both inguinal regions and placement of sterile drapes, local anesthesia with 2% lidocaine was administered. The right femoral artery was punctured using the Seldinger technique, and a 6F introducer was placed. Spinal angiography was performed from T12 to T5 in an ascending manner using a Simmons 1 catheter and a Terumo 0.035” hydrophilic guide, identifying the fistula in the right radicular artery (Fig. 2A). Angiography of the right T6 segmental artery in AP and lateral projections revealed a spinal dural fistula involving the radicular artery and ectasia of the radicular and spinal veins in the midline and posterior portion of the spinal canal, with a lateral short-circuit to the ipsilateral pedicle. Angiography of the right T7 segmental artery showed involvement of a superior dural fistula, with opacification of the dorsal branch of the ipsilateral posterior spinal artery and the radiculomedullary vein, along with the aforementioned posterior intrathecal ectasia in the venous phase.
(A) Spinal angiogram in anteroposterior projection, with selective catheterization of the right T6 segmental artery, revealing a dural arteriovenous fistula at the right T6 level supplied by a radicular artery. Note the ascending perimedullary vein (V. Espinal). (B) Spinal angiogram in anteroposterior projection, with access to the segmental artery via a Simmons 1.5-French catheter and a superselective 1.2-French Magic microcatheter through the right T6 radicular artery. Note the ascending perimedullary vein (V. Espinal). (C) Spinal angiogram after injection into the right T6 radicular artery, in anteroposterior projection, showing complete disappearance of the fistula.
Hyper-selective catheterization of the right T6 radicular artery was performed using a 1.2-French Magic microcatheter (Fig. 2B). The microcatheter was positioned at the entrance of the dural fistula using a Hybrid 007 microguidewire, and its placement was confirmed in AP and lateral projections. A 5% glucose solution was infused through the catheter tip under subtraction fluoroscopy, followed by the infusion of 0.5 ml of a low-concentration solution of Histoacryl™ n-butyl cyanoacrylate (30% nBCA, 70% lipiodol) for embolization. The infusion continued until occlusion of the draining vein was observed. A final angiogram of the T6 segmental artery confirmed complete obliteration of the fistula (Fig. 2C). The catheter was then removed, and the procedure was concluded without complications. The introducer was removed with manual compression, and no hematoma or other complications were noted.
Over the following 8 months, the patient’s symptoms gradually improved. Follow-up evaluations in the outpatient setting included physical examinations and imaging. By the final visit, the patient had experienced complete recovery of limb strength, sphincter control, and sensory function. The final assessment recorded a score of 2 on the mRS and 4 on the Aminoff-Logue Score. The patient was referred to physical therapy for rehabilitation and continued clinical improvement.
DISCUSSION
Due to the characteristics of the dural fistula, which involves a radicular feeding artery in its components and involves perimedullary venous drainage, although it has similarities such as type IV, which depends on an anterior medullary artery and can be subdivided into the simple (IV a), fed by only one arterial branch; the intermediate size (IV b), with multiple and dilated arterial afferents and the giant (IV c), which has multiple pedicles, does not have sufficient afferents, so it is classified as a type I [9,10].
Despite the publication of several case series and reports documenting successful resolution of dural arteriovenous fistulae using both endovascular and neurosurgical approaches, no consensus has been established for the definitive treatment of this condition, including cases with F-A syndrome. Nonetheless, in clinical practice, surgery is still preferred over endovascular treatments [1,3,11].
Endovascular embolization has been evaluated and reported with mixed to positive results in spinal dural arteriovenous fistulae, including those associated with F-A syndrome. Later studies have demonstrated higher success rates for embolization treatments [1,6,11]. Therefore, such approaches may become a viable option for patients who are not candidates for surgical ligation.
The patient’s anatomical structure has been shown to influence several aspects of embolization, including successful catheterization, the number of embolization attempts, occlusion of the draining vein, and clinical outcomes [1,12]. This case presented the necessary anatomical characteristics for successful hyper-selective embolization on the first attempt, particularly easy access to the fistula site from the segmental artery and successful occlusion of the draining vein. The treating team opted for an endovascular treatment due to the lower complication rates, minimal invasive approach posed by this modality, as well as the personal preference of the patient.
A recent meta-analysis suggested that patients may benefit from therapeutic interventions, whether surgical or endovascular, if performed early in the course of the disease, especially within six months of disease onset [4]. The research also recommended the use of the Aminoff-Logue and mRS to document improvement, particularly in such patients. Our patient showed improvement from an mRS of 4 to 2 and an Aminoff-Logue Score of 8 to 4. This reinforces the potential for better clinical outcomes when proper diagnosis and treatment are achieved within the recommended timeframe.
According to Gadot, high-level dural arteriovenous fistula treatment should consist of transvenous or transarterial endovascular embolization or open surgery with microsurgical interruption or stereotactic radiosurgical salvage therapy, always aiming to reduce the risk of permanent neurological deficits. Determining variables include the caliber and location of small vessels to assess endovascular treatment feasibility [8].
Endovascular embolization for dAVF has several advantages, including being less invasive and producing excellent outcomes. However, another important factor is the support provided by the guiding catheter, which ensures adequate stability for microcatheter insertion [3,6].
While endovascular treatment is an alternative to surgery, its disadvantages include cost, a higher risk of recurrent fistula, and the potential occlusion of the radiculomeningeal arterial branch, which is closely related to spinal cord vascularization [11].
Intramedullary embolization of dAVF has become a critical part of treatment, either in conjunction with surgery or as a standalone procedure. Modern microcatheters now allow embolization with particles, which can achieve more permanent occlusion but require annual angiographic follow-up. However, they may also cause concurrent embolization of normal perforating arteries. The use of particles is recommended whenever feasible, particularly in cases where embolization is the sole treatment option [13,14].
Surgical treatment has shown favorable outcomes when the fistula is located on the dorsal surface of the spinal cord, particularly at the conus medullaris level. However, for fistulas located ventrally and above the conus medullaris with a large feeding artery, careful consideration should be given to endovascular treatment. For type IV c perimedullary arteriovenous fistulas, endovascular treatment could be an optimal option [15]. Although both embolization and surgical treatments yield good results, the indication for each remains a topic
CONCLUSIONS
In conclusion, patients who develop F-A syndrome, with or without rapid clinical progression, and who are diagnosed early in the disease, should receive appropriate treatment as soon as possible. Many of these cases may benefit from endovascular closure of the fistula, regardless of whether surgery is being considered.
Acknowledgements
The authors of this case report did not receive any funding or outside sponsorship, including drugs, materials and devices.
Notes
Disclosure
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.