Arteriovenous Fistula of the Filum Terminale: A Case Report and Review of the Literature

Spinal Adhesive Arachnoidopathy, the Disorder More Than Simply Adhesive Arachnoiditis: A Comprehensive Systematic Review of 510 Cases

BACKGROUND

Spinal adhesive arachnoidopathy (SAA) is a chronic pathology associated with persistent inflammatory responses in the arachnoid. Adhesive arachnoiditis (AA) is one of the major forms of SAA, with accompanying secondary complications. Therefore, we aimed to systematically review both clinical and animal model studies related to SAA to gain a deeper understanding of this unique pathology.

METHODS

A literature search was conducted in PubMed, EMBASE, and Cochrane Library databases to retrieve relevant publications up to October 2022. Clinical manifestations, etiologies, imaging modalities, treatments, and prognosis in patients with SAA were collected. Data from animal experiments related to SAA were also extracted.

RESULTS

A total of 176 studies, including 147 clinical and 29 animal model studies, with a total of 510 patients were enrolled in this study. Pain (37.5%), abnormal nerve sensations (39.58%), and abnormal motor function (78.75%) were the top three common symptoms of SAA. Major etiologies included trauma (22.7%), infection (17.73%), surgery (15.37%), and hemorrhage (13.48%). MRI was widely used to confirm the diagnosis. AA could be involved in cervical (96/606, 15.84%), thoracic (297/606, 49.01%), lumbar (174/606, 28.71%), and sacrococcygeal (39/606, 6.44%) vertebral segments. Patients with AA in cervical segments had a higher post-surgery recovery rate (p = 0.016) compared to that of other segments. The common pathological diagnoses of SAA were AA (80.82%), AA combined with arachnoid cyst (12.79%), arachnoid calcification/scars (3.43%), and arachnoid web/fibrosis (2.97%). Patients with AA were more likely to develop syringomyelia, compared with patients with other forms of SAA (p < 0.001). Animal studies mainly focused on new AA therapeutic agents (n = 14), the pathomechanism of AA (n = 14), and the development of new MRI sequences for improved diagnosis (n = 1).

CONCLUSIONS

The pathological consequences of SAA are more complex than AA and manifest in different forms, such as AA combined with arachnoid cyst, arachnoid calcification/scars, and arachnoid web/fibrosis. In many instances, AA was associated with secondary syringomyelia. Unspecific clinical manifestations of SAA may easily lead to misdiagnosis and missed diagnosis. Although SAA may result from multiple etiologies, including spinal trauma, meningitis, spinal surgery, and hemorrhage, the pathogenesis and treatment of SAA have still not been standardized.

Treatment of filum terminale pial arteriovenous fistulas in the sacral region: A case report and systematic review

Spinal filum terminale pial arteriovenous fistulas (FT PAVFs) are uncommon. Most FT PAVFs are located in the lumbar region; far fewer are located in the sacral region. Due to the rarity of sacral FT PAVFs, the precise surgical dissection and removal of these lesions are challenging. Here, we report an FT PAVF in the sacral region. The patient was a 45-year-old male who suffered from progressive weakness and numbness of the bilateral lower limbs; his symptoms gradually worsened. Digital subtraction angiography (DSA) showed an AVF at the sacral canal at the S3-4 level. Microsurgical treatment with intraoperative DSA was performed, and the FT PAVF was resected. After the operation, the patient gradually recovered. Follow-up magnetic resonance imaging revealed a recession in the dilation of the spinal cord venous plexuses. A literature review was also performed, and a total of 14 FT PAVFs of the sacral region were identified. The patients identified in the literature review had an average age of 58.9 ± 12.9 years, and 92.9% of the patients were male. Spinal cord edema was present in 85.7% of the FT PAVF patients. Regarding treatment, 64.3% of the FT PAVF patients underwent microsurgical resection, 28.6% patients underwent endovascular treatment, and 7.1% patients underwent a hybrid operation; good outcomes were achieved with all three methods. Therefore, FT PAVF of the sacral region is a unique lesion whose angioarchitecture needs to be identified carefully; prompt treatment is necessary, and microsurgery can yield good outcomes.

Clip Ligation and Disconnection of a Ruptured Ventral Subaxial Cervical Isolated Spinal Aneurysm Using Tailored Access Osteotomies: An Operative Technique

BACKGROUND

Isolated spinal aneurysms (iSAs) are lesions of the spinal vasculature with no associated vascular malformation with difficult management paradigms limited by safe access.

OBJECTIVE

To describe a case of an irregular fusiform ruptured distal subaxial cervical spine iSA with a complex angioarchitecture intimately associated with the ventral pial plexus (VPP), treated using open clip ligation and disconnection.

METHODS

A 51-year-old woman presented with complete spinal cord injury with a C8 sensory level and ventral subarachnoid hemorrhage at the C6-T1 vertebral levels. After emergent anterior evacuation and fusion, angiography revealed a small iSA around the VPP. A total laminectomy spanning C5 to T3 was completed, and bilateral C7 pedicle resections were performed. A temporary clip was placed from the left for proximal control, and a permanent clip was placed across the dome of the distal vessel for disconnection. The dura was then closed, and a cervicothoracic fusion completed.

RESULTS

Postoperative angiography confirmed iSA disconnection and obliteration with anterior spinal artery preservation. The patient had intermittent numbness in the right C8 dermatome. On postoperative day 1, she regained proprioception in the right foot and movement in the lower extremities on command. On postoperative day 3, she regained full sensation and voluntary movement in both lower extremities.

CONCLUSION

iSA is a rare and morbid condition with nonstandardized guidelines regarding management. We promote the concept of using tailored osteotomies to establish safe corridors for the open treatment of difficult subaxial cervical ventral lesions not amenable to transarterial treatment. Multidisciplinary collaboration is promising, and further investigation is highly warranted.

Arteriovenous malformations of the filum terminale: clinical characteristics, angioarchitecture, and management of a rare spinal vascular pathology

OBJECTIVE

The goal of this study was to describe clinical and neuroradiological features of arteriovenous malformations of the filum terminale (FT AVMs) and to present the authors’ diagnostic and therapeutic management in this rare disease.

METHODS

The presented cases were retrieved from a retrospectively collected database of all spinal vascular malformations treated between June 1992 and December 2021 at the Rheinisch-Westfälische Technische Hochschule (RWTH) University Hospital Aachen. Pretreatment and follow-up clinical and neuroradiological data were analyzed for this study.

RESULTS

Data in 15 patients with FT AVM with a mean age of 60 years were included, with an overall incidence of FT AVM of 19% among all spinal AVMs in our cohort. Twelve of 15 (80%) patients were men. Nonspecific but typical clinical and MR findings of thoracolumbar congestive myelopathy were found in all patients. Spinal MR angiography, performed in 10 patients, identified in all cases the arterialized FT vein as well as a lumbar/lumbosacral location of an AV shunt. Digital subtraction angiography (DSA) showed an arterial supply solely via the FT artery in 12/15 (80%) patients and via an additional feeder from the lumbosacral region in the other 3/15 (20%) patients. All patients were treated surgically. During 1-year follow-up, 2 patients presented with recurrent FT AVM due to further arterial supply from the lumbosacral region, and were treated surgically. Neurological status was improved in all patients within the 1-year follow-up, with marginal further changes during long-term follow-up.

CONCLUSIONS

Congestive myelopathy is the major pathological mechanism of symptoms in these patients, with no evidence for intradural bleeding. Missing the presence of possible multiple arterial supply of FT AVM during DSA may result in misdiagnosis and/or insufficient treatment. Due to the frequently prolonged course of FT artery, resection of the FT AVM may be a favorable treatment modality in comparison with endovascular treatment. Follow-up examinations are obligatory within the first 3 years after treatment, and further MR angiography and DSA examinations are indicated if congestive myelopathy persists.

Sacral dural arteriovenous fistula of the filum terminale coexisting with partially thrombosed filum vein: A case report and literature review

Background:

Filum terminale arteriovenous fistulas (FTAVFs) are rare and usually classified as intradural ventral AVFs or Type IVa perimedullary fistulas, located on the pia surface along the course of filum terminale internum (FTI). We report an extremely rare case of sacral dural arteriovenous fistula of the FT. We also review the occurrence of FTAVFs in the sacral region.

Case Description:

A 64-year-old man presented with progressive weakness of the lower extremities for 3 months and bowel/bladder dysfunction following long history of back pain radiating to both legs. Magnetic resonance imaging of the lumbosacral and thoracic spine showed spinal cord congestion, extending from the conus medullaris to the level of T3, and partial thrombosis within the abnormal tortuous and dilated flow void, running from the sacral area to conus medullaris. Further findings were compression fracture of L2 vertebra, Grade I degenerative spondylolisthesis at the level of L2-3, and L3-4, and spinal stenosis at L2-3, L3-4, and L4-5. Spinal angiography, maximum intensity projection reformatted image of angiographic computerized tomography, and three-dimensional reconstructed image clearly demonstrated dural AVF of the FT at the level of S2 supplied by bilateral lateral sacral and middle sacral arteries with cranial drainage to perimedullary vein through the enlarged vein of the filum. The patient was indirectly treated by transection of the filum terminale and the draining vein at the level of L5 rostral to the fistula.

Conclusion:

Sacral DAVFs of the FT are extremely rare. In our case, the formation of fistula may cause by venous hypertension secondary to partial thrombosis within the filum vein, probably resulting from long-standing spinal canal stenosis. Sacral FTAVFs may be found on the pia surface of the terminal FTI, dural component at the area of dural sac termination, or dural extension covering the filum terminale externum.

Filum Terminale Arteriovenous Fistula with Additional Arterial Supply by the Posterior Spinal Artery: A Report of Two Cases

Filum terminale arteriovenous fistulas (FTAVFs) are rare and usually supplied by the artery of the filum terminale, distal termination of the anterior spinal artery (ASA). These fistulas may also supply from the lateral sacral artery (LSA) arising from the internal iliac artery and/or middle sacral artery. Additional supply by the posterior spinal artery (PSA) has never been mentioned before. The authors describe two middle-aged men harboring FTAVFs manifested with progressive myelopathy and bowel/bladder dysfunction. The first fistula was supplied by the ASA with additional supply by the dilated PSA connecting with the ASA. Another fistula was supplied by the LSA and the PSA communicating with the ASA. The first case was successfully treated by endovascular treatment with N-butyl cyanoacrylate through the enlarged PSA, whereas the second case was surgically treated by direct obliteration of the fistula. Both patients had good neurological outcome.

Spinal epidural arteriovenous fistula with intradural venous reflux: The possibility of acquired origin caused by spinal stenosis and/or disc herniation

BACKGROUND

Spinal epidural arteriovenous fistulas (SEAVFs) are relative rare lesions. The pathogenesis of these fistulas remains unclear. Our aim is to review cases of SEAVFs at our institution.

METHODS

We reviewed a consecutive series of spinal vascular disease at our institution and collected all patients harboring SEAVFs. Medical charts were retrospectively reviewed regarding patient demographic data (i.e., gender and age), presenting symptoms and signs, previous history of spinal surgery or trauma, treatment methods, and neurological outcome after treatment. All image studies, including plain radiography, spinal MRI, MRA, and angiography were analyzed.

RESULTS

We identified 9 cases of lumbosacral SEAVFs with intradural venous reflux treated at our institution from June 2010 to August 2020. Their median age was 67 years, range 52-83 years. Only one patient had a history of trauma. Interestingly, our observations found that all fistulas are associated with spinal stenosis and/or disc herniation. An additional literature search about SEAVFs coexisting with spinal stenosis and/or disc herniation was performed and found another 19 cases with median age 69 years, range 39-83 years. Only 2 patients had a history of previous spinal surgery. The level of shunted pouch in all 28 patients was correlated with the level of spinal canal stenosis and/or disc herniation.

CONCLUSIONS

Our study may provide an additional evidence supporting an acquired etiology of SEAVFs, which mainly manifest in late adulthood. It is possible that spinal stenosis and/or disc herniation may result in thrombosis or impairment of venous drainage, causing increased venous pressure, leading to fistulous formation.

Filum Terminale Arteriovenous Fistula Coexisting with a Large L2-L3 Disc Sequestration and Associated Diffuse Lumbar Arachnoiditis

The authors describe a case of filum terminale arteriovenous fistula (FTAVF) in association with a large L2–L3 disc sequestration and diffuse lumbar arachnoiditis. A 64-year-old male manifested with chronic back pain and gait difficulty. Magnetic resonance imaging (MRI) of the thoracic and lumbosacral spine revealed spinal cord congestion extending from the conus medullaris to the level of T9. There was a large disc sequestration came from L2–L3 disc herniation. In addition, thickening, clumping, and enhancement of the entire cauda equina were noted, probably representing arachnoiditis. MR angiography (MRA) and spinal angiography confirmed FTAVF at the level of L5. The patient underwent laminectomy with lysis adhesions and obliteration of the fistula. His postoperative course was uneventful. MRI and MRA of the thoracolumbar spine obtained 4 months after surgery revealed complete obliteration of the fistula and significant resolution of spinal cord congestion. Enhancement of the cauda equina roots was no longer visible. Interestingly, the significant resorption of the sequestrated disc was documented on MRI. The formation of the FTAVF in the present study may result from severe spinal canal stenosis caused by a large disc sequestration blocking the rostral venous drainage of the fistula, or chronic inflammation, and adhesions of the caudal nerve roots from lumbar arachnoiditis. It seems that FTAVF may be of acquired origin by this evidence.

Arteriovenous fistula of the filum terminale masqueraded as a failed back surgery syndrome - A case report and review of literature

BACKGROUND

The filum terminale arteriovenous fistulas (FTAVFs) are a very rare type of spinal vascular malformation. Clinically, these lesions could present with a progressive ascending myelopathy also called FoixAlajouanine syndrome. Due to the rarity of these vascular malformation, some can be misdiagnosed, submitted to unnecessary spinal surgery, and even masqueraded as a failed back surgery syndrome. Based on the present case and related literature, we review all the cases with similar history and describe factors that should raise awareness for diagnosis of this spinal vascular malformation.

CASE DESCRIPTION

We present a case of a patient with a FTAVF at the level of L5-S1 that presented with a FoixAlajouanine syndrome. He had been previously submitted to a lumbar decompressive laminectomy without sustained improvement. After the identification and surgical treatment of the vascular malformation, he had progressive neurological improvement.

CONCLUSION

FTAVF is a very rare spinal intradural spinal vascular malformation that can be masqueraded as a failed back surgery syndrome. In these cases, signs of ascending myelopathy should prompt awareness and vascular voids must be carefully evaluated in MRI.

Spinal arteriovenous fistula located in the filum terminale externa: A case report and review of the literature

A filum terminale arteriovenous fistula (FTAVF) is an extremely rare spinal arteriovenous fistula (AVF) and typically presents with myelopathy and conus medullaris syndrome caused by venous congestion in the spinal cord. Most reported FTAVFs are intradural pial AVFs with perimedullary drainage in the filum terminale interna. However, there are no reports of AVFs in the filum terminale externa (FTE). We describe a case involving a 68-year-old man with an AVF in the FTE who presented with progressive myelopathy and underwent successful endovascular treatment. We identified the specific shunt point by fusing postoperative computed tomography and magnetic resonance images. The features of the extradural sac AVF developed in the FTE may mimic those of a dural AVF with dural supply to the FTE covered by the dural component, unlike typical FTAVFs where the shunt develops at the pia mater. This case makes a significant contribution to the field by increasing the understanding of the clinical characteristics of an AVF that develops in the FTE and its angioarchitecture.

Cauda Equina and Filum Terminale Arteriovenous Fistulas: Anatomic and Radiographic Features

Intradural AVF below the conus medullaris may develop either on the filum terminale or the cauda equina (lumbosacral and coccygeal radicular nerves). Although not a few filum terminale AVFs are found in the literature, only 3 detailed cauda equina AVFs have been reported. Here, we analyze the angiographic and MR imaging findings of our cauda equina and filum terminale AVF cases, supplemented with literature research to characterize the radiologic features of the 2 entities. On angiography, filum terminale AVFs were invariably supplied by the extension of the anterior spinal artery accompanied by a closely paralleling filum terminale vein. Cauda equina AVFs were fed by either a radicular or a spinal artery or both arteries, often with a characteristic wavy radicular-perimedullary draining vein. On thin-section axial MR imaging, the filum terminale AVF draining vein joined the spinal cord at the conus medullaris apex, but that of the cauda equina AVF joined above the conus medullaris apex.

Recurrent arachnoid cysts secondary to spinal adhesive arachnoiditis successfully treated with a ventriculoperitoneal shunt

Spinal adhesive arachnoiditis (SAA) with cyst formation secondary to infectious meningitis is a rare clinical entity. These cysts can compress the spinal cord and cause neurologic decline. We present a case of a patient who underwent resection for an intradural schwannoma which was complicated post-operatively by bacterial meningitis and development of several recurrent thoracic arachnoid cysts. After two separate thoracic decompressions with lysis of intradural adhesions, a permanent ventriculoperitoneal shunt (VPS) was eventually placed with complete recovery of his symptoms. Our review of the literature showed that CSF shunts have previously been successfully used to treat spinal fluid collections. Although there are many factors to consider when treating these patients, CSF diversion may be beneficial for similar SAA presentations in order to simultaneously treat and prevent recurrence of symptoms.

Filum Terminale Arteriovenous Fistula in Association with Degenerative Lumbosacral Spinal Canal Stenosis: Report of 3 Cases and Review of the Literature

BACKGROUND

Filum terminale arteriovenous fistulas (FTAVFs) are rare, and the pathogenesis of these fistulas remains unclear. They may be either congenital or acquired in origin. The authors report 3 cases of FTAVFs in association with severe spinal canal stenosis. The authors also review literature of FTAVFs associated with spinal canal stenosis.

CASE DESCRIPTION

All 3 cases harboring FTAVFs manifested with progressive myelopathy and bowel/bladder dysfunction following long history of back pain, sciatica, and/or intermittent claudication. The fistulas were located around or at the level of spinal canal stenosis and supplied by the anterior spinal and/or lateral sacral arteries with cranial drainage from the dilated vein of the filum terminale to the perimedullary veins. The first and third cases were treated concomitantly by performing instrumented fusion with decompressive laminectomy along with occlusion of the fistula with good results. The second case was unsuccessfully treated by endovascular treatment through the lateral sacral artery and denied further surgical treatment.

CONCLUSIONS

Our 3 case reports may provide additional evidence supporting an acquired etiology of FTAVFs, probably secondary to the severe central canal stenosis. From our review, the level of the fistulas in most patients is correlated with the level of spinal canal stenosis. The authors preferred the concomitant surgical treatment by performing decompressive laminectomy and obliteration of the fistula in the same surgical session.

Spinal Sparganosis Coexisting with Acquired Arteriovenous Fistula of the Filum Terminale

BACKGROUND

Spinal sparganosis associated with filum terminale arteriovenous fistula (FTAVF) has not been reported in the literature. In previous studies, these 2 rare diseases were usually reported separately. We report the first case of spinal sparganosis with concomitant FTAVF.

CASE DESCRIPTION

Spinal sparganosis associated with FTAVF manifested in a middle-aged man with progressive back pain and paraparesis. Magnetic resonance imaging of the lumbosacral spine revealed large intradural mass-like lesions involving the conus medullaris and entire cauda equina. Additionally, there was degenerative spinal stenosis at the level of L2-3 to L5-S1. Magnetic resonance imaging of the thoracic spine disclosed abnormal hypersignal intensity extending from the level of the conus medullaris to T7 with tortuous intradural flow voids along the ventral more than dorsal surfaces of the spinal cord. Magnetic resonance angiography and spinal angiography confirmed FTAVF at the level of L3-4. The patient underwent surgical removal of the granulation tissues with lysis adhesions and obliteration of the FTAVF simultaneously in the same surgical session. Histologic findings were consistent with sparganosis.

CONCLUSIONS

The formation of FTAVF in the present case may have resulted from severe spinal canal stenosis caused by lumbar spondylosis and spinal sparganosis, inducing chronic inflammation and severe adhesion of spinal nerve roots. This evidence indicates that FTAVF may have been acquired.