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

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.

Coexisting filum terminale arteriovenous fistula and filum terminale lipoma treated with single-stage surgery: illustrative case

BACKGROUND

Both filum terminale arteriovenous fistulas (FTAVFs) and filum terminale lipomas (FTLs) are rare. Because of this rarity, there is a paucity of data regarding concomitant FTAVF and FTL, and the optimal treatment remains to be defined. The authors describe a patient with coexisting FTAVF and FTL treated with single-stage surgery.

OBSERVATIONS

A man in his 70s was referred to the authors' department because of a suspected spinal vascular malformation seen on magnetic resonance imaging that was performed to investigate lower limb weakness, intermittent claudication, and urinary incontinence. Previous imaging had shown a terminal lipoma with an internal flow void. Computed tomography angiography and digital subtraction angiography revealed an FTAVF, the feeder being a lateral sacral artery. The patient was treated surgically with curative intent. The FTL and tethered cord that had been identified by imaging were treated in the same procedure. Postoperative digital subtraction angiography showed absence of the abnormal vessels. The patient was discharged home on the 19th postoperative day.

LESSONS

When considering treatment, it is important to determine whether symptoms are attributable mainly to FTL, tethered cord, or FTAVF. One-stage treatment is useful because it eliminates both the FTAVF and the factors that led to its development.

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.