Coincidence of Tethered Cord, Filum Terminale Lipoma, and Sacral Dural Arteriovenous Fistula: Report of Two Cases and a Literature Review

Coexistence of neural tube defects and spinal arteriovenous shunts: a case series and review of literature

BACKGROUND

Spinal arteriovenous shunts and spinal dysraphism both have a different underlying cause, disease spectrum and developmental process; hence, these entities rarely coexist in a patient. Here, we reported four cases of coexistence of adult-onset spinal arteriovenous shunt and spinal dysraphism in the same patient along with their therapeutic embolisation. Additionally, we conducted an extensive literature review to explore the potential theories and explanations for this coexistence.

METHODS

We retrospectively searched our imaging database from January 2015 to December 2023 to identify instances of spinal arteriovenous shunts occurring in patients with spinal dysraphism or neural tube defect disorders. MRI and angiographic imaging, clinical presentation, treatment and follow-up were analysed.

RESULTS

Four patients with arteriovenous fistula/shunt and spinal dysraphism were included in the study. The mean age of presentation was 35.5 years. The most common symptoms were sensory disturbance and motor weakness. Arteriovenous fistula or shunt was located at the lumber region in one patient and at the sacral region in three cases. Two patients have a prior history of surgery in first decade. Two patients were treated with glue embolisation. The internal iliac artery was a common feeder in all cases.

CONCLUSIONS

The rare coexistence of neural tube defects with spinal vascular abnormalities should be considered when assessing a middle-aged patient with neural tube defect and myelopathy. Correct diagnosis can help in treatment planning and thereby improve prognosis.

Usefulness of time-resolved MR angiography in spinal dural arteriovenous fistula (SDAVF)-a systematic review and meta-analysis

Spinal dural arteriovenous fistulas (SDAVFs) constitute the most common type of spinal vascular malformations. Their diagnosis requires spinal digital subtraction angiography (DSA), which is time-consuming, requires catheterizing many vessels, and exposes patient to a high radiation and contrast doses. This study aims to evaluate the usefulness of time-resolved MR angiography (TR-MRA) in SDAVF diagnosis. We performed a systematic review of the PubMed and EMBASE databases followed by a meta-analysis. TR-MRA was an index test, and spinal DSA was a reference. Of the initial 324 records, we included 4 studies describing 71 patients with SDAVFs. In 42 cases, TR-MRA was true positive, and in 21 cases, it was true negative. We found 7 false-positive cases and 1 false negative. TR-MRA allowed for shunt level identification in 39 cases. Of these, the predicted level was correct in 23 cases (59%), to within 1 level in 38 cases (97.4%) and to within 2 levels in 39 cases (100%). The diagnostic odds ratio was 72.73 (95% CI [10.30; 513.35]), z = 4.30, p value < 0.0001. The pooled sensitivity was 0.98 (95% CI [0.64; 1.00]), and the pooled specificity was 0.79 (95% CI [0.10; 0.99]). The AUC of the SROC curve was 0.9. TR-MRA may serve as a preliminary study to detect SDAVFs and localize the shunt level with sensitivity and specificity as high as 98% and 79%, respectively. Unless the TR-MRA result is unequivocal, it should be followed by a limited spinal DSA.

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 Extradural Angiolipoma Associated with Tight Filum Terminale and Spina Bifida Coexisting with Spinal Arteriovenous Fistula

BACKGROUND

Spinal arteriovenous fistula (AVF) may rarely associate with spinal dysraphism, that is, tethered spinal cord and spinal intradural lipoma. Spinal extradural angiolipoma coexisting with spinal AVF has not been reported in the literature. We reported an extremely rare case of sacral angiolipoma associated with tight filum terminale and sacral spina bifida coexisting with spinal AVF within this tumor.

CASE DESCRIPTION

A 55-year-old women presented with progressive myelopathy for 10 months. She had a painless, slow-growing mass at her left buttock since birth. Magnetic resonance imaging of the lumbosacral spine showed an extradural mass at the level of S3-S4, extending from the spinal canal through the spina bifida to the subcutaneous fat of the left buttock. There was a low conus medullaris at S2. Magnetic resonance imaging of the thoracic spine disclosed venous congestion with tortuous intradural flow voids along both ventral and dorsal surfaces of the spinal cord. Magnetic resonance angiography and spinal angiography revealed a hypervascular mass at the sacral level and associated arteriovenous shunt with cranial drainage into an enlarged medullary vein. Due to an infected pressure sore on the mass, endovascular treatment was initially performed with minimal recovery. Six months after complete healing of her infected pressure ulcer, the patient underwent surgical removal of extradural mass containing the AVF, and subsequent release of the tight filum. Histologic findings were consistent with angiolipoma.

CONCLUSIONS

Sacral extradural angiolipoma in the present case may be congenital in origin with development of an acquired spinal AVF within the tumor.

Coincidence of Tethered Cord, Filum Terminale Lipoma, and Sacral Dural Arteriovenous Fistula: Report of Two Cases and a Literature Review

Spinal dural arteriovenous fistula (SDAVF) is the most common vascular malformation of the spine in adults. However, the coincidence of tethered cord syndrome, lipoma, and SDAVF on the sacral level is exceptionally rare. We describe two patients, probably the fifth and sixth ever reported. The first was a 33 year-old female who underwent surgical cord de-tethering. Surprisingly, a sacral SDAVF was discovered intraoperatively, despite negative digital subtraction angiography (DSA). The second patient was a 30 year-old male with similar pathologies. After three failed embolizations, the fistula was surgically disconnected. Both patients recovered well. A review of patients with sacral SDAVF coexisting with spinal dysraphism, with an emphasis on the basis of symptoms was done. As a rule, in these coincident disorders, the SDAVF was the direct cause of increasing symptoms. Previous reports and our findings reveal that surgery might be superior to endovascular embolization for treating sacral SDAVFs with coexisting entities, because surgery offers a one-step treatment.