
==== Front
Int J Surg Case Rep
Int J Surg Case Rep
International Journal of Surgery Case Reports
2210-2612
Elsevier

S2210-2612(24)01019-8
10.1016/j.ijscr.2024.110238
110238
Case Report
Embolization of an epidural arteriovenous fistula of the sacral nerve root with a neural tube defect: A case report
Yu Jinlu jlyu@jlu.edu.cn
⁎
Department of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021, China
⁎ Corresponding author at: Department of Neurosurgery, The First Hospital of Jilin University, 1 Xinmin Avenue, Changchun, Jilin 130021, China. jlyu@jlu.edu.cn
03 9 2024
10 2024
03 9 2024
123 11023815 7 2024
23 8 2024
31 8 2024
© 2024 The Author
2024
https://creativecommons.org/licenses/by-nc-nd/4.0/ This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Introduction and importance

Rarely, epidural arteriovenous fistula (AVF) of the sacral neural root may be associated with neural tube defects.

Case presentation

A 46-year-old man presented with progressive weakness and numbness in both lower extremities. On physical examination, both lower extremities only had Grade III muscle strength. MRI revealed extensive dilated veins along the spinal cord, edema of the spinal cord, lipomyelomeningocele and tethering of the spinal cord. Angiography revealed an epidural AVF at the sacral neural root with intradural venous drainage. Endovascular treatment (EVT) was performed. First, a microcatheter accessed the AVF; then, another microcatheter coiled around the feeding artery near the fistula to establish the “pressure cooker” effect; finally, the AVF was obliterated by casting Onyx via the first microcatheter. After EVT, the patient's symptoms improved immediately. Postoperative computed tomography confirmed the presence of defective sacral bone. Based on the patient's physical examination and imaging findings, a neural tube defect with a tethered cord and a lipomyelomeningocele were confirmed. Two months later, the patient recovered well and could walk. The follow-up MR image revealed a nearly normal spinal cord.

Clinical discussion

Microsurgical resection is difficult because of the deep location of such an AVF. EVT by casting Onyx can be a feasible option. To avoid Onyx reflux, the ‘pressure cooker’ technique can be helpful for obliterating such an AVF.

Conclusion

On the basis of this case report, EVT can be effective for epidural AVFs of the sacral neural root in select cases.

Highlights

• AVFs of sacral neural root may rarely be associated with neural tube defect.

• Surgery is difficult to treat such an AVF.

• Endovascular treatment can be effective.

Keywords

Sacral neural root
Arteriovenous fistula
Embolization
Prognosis
==== Body
pmc1 Introduction

Epidural arteriovenous fistulas (AVFs) of the sacral neural root may rarely be associated with neural tube defects (1). We reported such an AVF with intradural drainage in a patient with a neural tube defect. The patient presented with symptoms of spinal cord injury, which prompted the intervention. Currently, microsurgical resection and endovascular treatment (EVT) can be used for symptomatic sacral neural root AVFs. Surgery is often difficult because of the deep location and complex anatomy of such an AVF (2). EVT by casting Onyx (Medtronic, Irvine, CA, USA) can be a feasible option to treat such an AVF. During EVT, Onyx may backflow along the microcatheter and thus prevents complete obliteration of the AVF. The ‘pressure cooker’ technique can be helpful for obliterating such an AVF (3). We reported such a technique.

Our work is in line with the SCARE criteria, which address the importance of patient privacy, consent, ethical considerations, and the need for clear and concise reporting of surgical procedures and outcomes (4).

2 Case presentation

A 46-year-old man presented with a 2-month history of progressive weakness and numbness in both lower extremities. He was of Han Chinese nationality. Physical examination revealed that the skin of his right hip protruded, resulting in a mass effect (Fig. 1A). He explained that the mass was asymptomatic and was present from birth. Both of his lower extremities had grade III muscle strength, and he could not walk and was confined to a wheelchair. There was a positive Babinski sign in both lower limbs. Below the clavicle, hypoesthesia was noted, presenting with reduced senses of touch, pain and temperature. He had occasional incontinence and retention and an Aminoff-Logue Scale score of 7 (motor, 5; urinary, 2) (Table 1) (5). Magnetic resonance imaging (MRI) revealed an enlarged sacral canal with liquid filling (Fig. 1B), a lipomyelomeningocele (Fig. 1C), dilated veins on the surface of the spinal cord from the sacrum to the T1 level, edema and tethering of the lower spinal cord (Fig. 1D).Fig. 1 Hip photograph and preoperative MRI.

A: Photograph showing the local deformity of the right hip with a mass effect (frame). B: Sagittal MR image of the T2 sequence showing the enlarged sacral canal with liquid filling (frame). C: Axial MR image of the T2 sequence (panels 1 and 2) showing a lipoma (asterisks) and a meningocele (arrows) of the right hip. D: Neck (number 1 panel), thoracic (number 2 panel) and lumbosacral (number 3 panel) MR images of the T2 sequence showing flow voids (arrowheads), indicating tortuous dilated veins, from the sacrum to the T1 level on the ventral and dorsal surfaces of the spinal cord; edema of the spinal cord (asterisks in panels 1 and 2); and tethering of the spinal cord (red arrow in the 3 panel).

Abbreviations: MRI: magnetic resonance image, R: right. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 1

Table 1 Aminoff-Logue Scale.

Table 1Grade	Motor	Urinary	
0	Normal	Normal	
1	Leg weakness, abnormal stance or gait, unrestricted activity	Hesitancy, urgency but no incontinence	
2	Restricted activity	Occasional incontinence or retention	
3	A crutch or other support is needed to walk	Total incontinence or retention	
4	Crutches are needed to walk		
5	Cannot stand; bedridden or confined to wheelchair		

Digital subtraction angiography (DSA) of the right internal iliac artery revealed an epidural AVF at the sacral neural root outside the sacrum canal, and the feeding artery was right lateral sacral artery termination. There were multiple venous drainage vessels, one of which went into the spinal canal via the sacral neural foramen (Fig. 2A). EVT was performed. First, one Echelon-10 microcatheter (Medtronic, Irvine, CA, USA) was used to access the shunt point of the AVF, which was then positioned to wait for the embolic agent to be cast. Another Echelon-10 microcatheter then coiled the feeding artery near the AVF before the tip of the first Echelon-10 microcatheter to establish the “pressure cooker” effect. Then, Onyx-18 (Medtronic, Irvine, CA, USA) was cast by the first Echelon-10 microcatheter, and the right lateral sacral artery termination, the AVF shunt point and multiple venous drainage vessels were occluded (Fig. 2B). DSA confirmed complete obliteration of the AVF. After EVT, the patient's symptoms improved immediately.Fig. 2 Embolization of the arteriovenous shunt.

A: Panel Number 1: DSA of the right internal iliac artery showing an arteriovenous shunt (asterisk) at the sacral neural root. The feeding artery (arrow) is the lateral sacral artery termination from the internal iliac artery, and the arrowheads indicate intradural drainage. Panel 2: DSA image showing the angioarchitecture of the arteriovenous shunt, which suggests an AVF; the arrow indicates the feeding artery; the asterisk indicates the fistula point; and the arrowheads indicate multiple venous drainages. Number 3 panel: Selective angiography of the Echelon-10 microcatheter showing the microcatheter tip (asterisk) at the fistula point. B: Number 1 panel: Roadmap DSA image showing the first Echelon-10 microcatheter (arrow) in the AVF. The feeding artery near the AVF was coiled through the second Echelon-10 microcatheter to establish the “pressure cooker” effect. Number 2 panel: Unsubtracted DSA image showing the casting Onyx (circle) in the AVF. Number 3 panel: DSA image showing that the AVF was obliterated.

Abbreviations: AVF: arteriovenous fistula, DSA: digital subtraction angiography, R: right.

Fig. 2

On the second postoperative day, pelvic computed tomography (CT) and lumbosacral MRI were performed. CT revealed that the sacral bone was defective (Fig. 3A). MRI revealed that the dilated draining veins of the spinal cord regressed (Fig. 3B). Based on his physical examination and imaging findings, a neural tube defect with a tethered spinal cord and a lipomyelomeningocele were confirmed. On the third postoperative day, the patient was discharged. He performed the recommended rehabilitation exercises and gradually recovered. After two months, he could walk (Fig. 3C). The Aminoff-Logue scale score was 1 (motor, 1; urinary, 0). Follow-up MRI revealed a nearly normal spinal cord (Fig. 3D).Fig. 3 Postoperative images and follow-up.

A: Postoperative three-dimensional reconstructed computed tomography images (anteroposterior view of the number 1 panel and posteroanterior view of the number 2 panel) showing a cast onyx (arrows) and no sacral bone at the AVF. B: Postoperative MRI of the T1 sequence (number 1 panel) and T2 sequence (number 2 panel) showing regression of the dilatated draining veins. C: Photograph showing that the patient could walk without help. D: Two-month follow-up MRI of the T1 sequence (number 1 panel) and T2 sequence (number 2 panel) showing a normal spinal cord with no dilated draining veins or edema.

Abbreviations: AVF: arteriovenous fistula; MRI: magnetic resonance image.

Fig. 3

3 Discussion

Sacral AVFs are rare and are mostly located in the sacral canal around the filum terminale or at the sacral foramen (2). Sacral epidural AVFs may occur in isolation but are rarely associated with neural tube defects, including intradural lipoma, lipomeningocele, myelomeningocele, tethered spinal cord, dermoid cyst, neuroenteric cyst and diastematomyelia (1). We reported such a case. In our case, the sacral bone at the AVF was defective, which caused the AVF to be located at the epidural sacral nerve root.

The coexistence of neural tube defects and sacral nerve root AVF may suggest a causal relationship due to incomplete regression of mesenchymal tissue during the embryonic period. Failure to form the capillary component of the mesoderm might lead to direct AVF (1,6). During the embryonic period, vascular differentiation in fat tissue is suppressed by neural crest cells. If neural crest cells are inhibited, a lipoma may develop, and a vascular malformation may form secondarily (7). In our case, the lipomeningocele and tethering spinal cord were associated with the AVF, which conformed to the above theory. Most patients with lipomeningomyelocele have early-onset deficits in tethered cord syndrome (8).

Lipoma itself and its tethering effect may impair spinal venous drainage and even result in intradural drainage. Finally, spinal cord venous hypertension can occur and result in progressive myelopathy, and these symptoms can occur until adulthood (9,10). For symptomatic epidural sacral neural root AVFs, prompt surgical intervention should be considered and performed. Treatment mainly included microsurgical resection or EVT. Unlike the shunt point of sacral dural AVFs, which tend to be located medially, epidural sacral nerve root AVFs are located in the sacral foramen. Surgical resection of epidural sacral nerve root AVFs is difficult because of the deep location and complex anatomy of the AVF.

EVT can be used to treat pial, dural or epidural sacral AVFs ([11], [12], [13], [14]). EVT aims to penetrate proximal draining veins with a liquid embolic agent. In our case, we selected the nonadhesive Onyx, which can be used for embolization of spinal AVFs (15). While the Onyx is being cast, the Onyx may backflow along the microcatheter. EVT with Onyx casting via the ‘pressure cooker’ technique may increase AVF obliteration (16). Therefore, we used this technique. The first Echelon-10 microcatheter was accessed close to the shunt point. Then, after creating the proximal plug with coils, another microcatheter was placed in the feeding artery near the AVF and Onyx was cast via the first working microcatheter, which obliterated the AVF.

In addition to plugs with coils, the ‘pressure cooker’ technique of dual-lumen balloon catheters can be used (17). The dual lumen balloon can be either regular or have a low profile, depending on the tortuosity of the arterial feeder. The dual lumen balloon catheter was then navigated as close as possible to the shunt point. The Onyx is subsequently injected through the working lumen, and the balloon is subsequently inflated to avoid Onyx reflux. However, balloon catheters are often stiff; if the feeding artery is tortuous, the catheter cannot be placed as close as possible to the shunt point. Therefore, we did not use this technique.

When performing EVT, injury to the anterior spinal artery (ASA) should be considered to avoid disastrous consequences. Kroszczynski et al. reported that <3 % of patients had an ASA arising at the sacral level (18). It is important to identify an ASA arising from such a low level. In Giordan et al.'s report of 6 patients with lumbosacral epidural AVFs associated with neural tube defects, one patient had a spinal cord infarct and consequent severe paraparesis due to embolization of an arterial feeder supplying the ASA (1). In our patient, no ASA was found, and there were no complications associated with EVT. Complete and early EVT is very important for accessing epidural sacral neural root AVFs. In our patient, the recovery was rapid, and follow-up MRI revealed that the edema had regressed because of early and complete EVT. In this case, although the patient had a neural tube defect, the relevant symptoms were absent and slim, and the malformation was treated conservatively until tethered cord syndrome developed.

4 Conclusion

On the basis of this case report, we found that, rarely, sacral neural root epidural AVFs can be associated with neural tube defects, resulting in symptoms of spinal cord injury due to intradural drainage. EVT with the assistance of the ‘pressure cooker’ technique can be effective in select cases, such as our case.

Consent

Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Ethical approval

Ethics approval was not required by the authors' institution, as the present study is a case report. Informed signed consent to participate was obtained from the patient.

Funding

None.

Research registration number

Not applicable. This is a case reports not a research study.

Guarantor

Jinlu Yu, Department of Neurosurgery, The First Hospital of Jilin University. E-mail: jlyu@jlu.edu.cn

Declaration of competing interest

The authors declare no conflict of interest.

Data availability statement

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Acknowledgment

None.
==== Refs
References

1 Giordan E. Bortolotti C. Lanzino G. Brinjikji W. Spinal arteriovenous vascular malformations in patients with neural tube defects AJNR Am. J. Neuroradiol. 39 3 2018 597 603 29284599
2 Guo Y. Yu J. Treatment of filum terminale pial arteriovenous fistulas in the sacral region: a case report and systematic review Neuroradiol. J. 36 3 2023 251 258 36086815
3 Lindgren A. Ahmed S.U. Bodani V. Andrade Barazarte H. Agid R. Kee T.P. Transarterial embolization of Dural arteriovenous fistulas: conventional, pressure cooker, and microballoon catheter embolization techniques Oper. Neurosurg. (Hagerstown) 2024 10.1227/ons.0000000000001066
4 Sohrabi C. Mathew G. Maria N. Kerwan A. Franchi T. Agha R.A. The SCARE 2023 guideline: updating consensus surgical CAse REport (SCARE) guidelines Int. J. Surg. 109 5 2023 1136 1140 37013953
5 Aminoff M.J. Logue V. The prognosis of patients with spinal vascular malformations Brain 97 1 1974 211 218 4434169
6 Chatkupt S. Ruzicka P.O. Lastra C.R. Myelomeningocele, spinal arteriovenous malformations and epidermal nevi syndrome: a possible rare association? Dev. Med. Child Neurol. 35 8 1993 737 741 8335163
7 Cheung AC, Kalkanis SN, Ogilvy CS. Paraplegia after tethered cord surgery: an uncommon combined anomaly of spinal arteriovenous fistula and sacral lipoma—case report. Neurosurgery. 2005;57(3):E598; discussion E.
8 Vepakomma D. Kumar N. Alladi A. Tethered cord syndrome-role of early surgery J. Indian Assoc. Pediatr. Surg. 24 2 2019 124 128 31105399
9 Przepiórka Ł. Kunert P. Juszyńska P. Zawadzki M. Ciszek B. Głowacki M. Coincidence of tethered cord, filum terminale lipoma, and sacral dural arteriovenous fistula: report of two cases and a literature review Front. Neurol. 9 2018 807 30319536
10 König M. Hentsch A. Schmieder K. Harders A. Heuser L. Extraspinal dural arteriovenous fistula in a patient with lipomyelodysplasia: value of MRI and MRA Neuroradiology 41 8 1999 579 583 10447569
11 Rahme R.J. Abi-Aad K.R. Almekkawi A.K. Patra D.P. Bendok B.R. Endovascular embolization of a lateral sacral fistula: 2-dimensional operative video Oper. Neurosurg. (Hagerstown) 19 3 2020 E313 32171002
12 Essibayi M.A. Srinivasan V.M. Catapano J.S. Graffeo C.S. Lawton M.T. Spinal dorsal intradural arteriovenous fistulas: natural history, imaging, and management Neurology 101 12 2023 524 535 37185123
13 Alvarado A.M. Haussen D.C. Ebersole K. Nogueira R.G. Abraham M.G. Embolization of sacral dural arteriovenous fistulas: a case series and literature review Interv. Neurol. 6 1–2 2017 73 81 28611837
14 Saito K. Ushioda T. Miyata T. Mayanagi K. Kato K. Inamasu J. A rare case of sacral epidural arteriovenous fistula with concomitant occult multiple lumbar epidural arteriovenous fistulas J. Cerebrovasc. Endovasc. Neurosurg. 25 3 2023 322 332 36514239
15 Su H. Yu J. Treatment of high cervical arteriovenous fistulas in the craniocervical junction region Front. Neurol. 14 2023 1164548 37441609
16 Parat D. Granger B. Shotar E. Premat K. Reina V. Drir M. ‘Pressure cooker’ and ‘balloon pressure’ techniques significantly increase 3-month complete occlusion rate after spinal arteriovenous fistula embolization as compared to glue: single center evaluation on 38 consecutive patients J. Neurointerv. Surg. 16 9 2023 914 920 10.1136/jnis-2023-020621
17 O’Reilly S.T. Hendriks E.J. Itsekson Z. Alshahrani R. Chung E. Radovanovic I. Utilisation of the scepter Mini dual-lumen balloon - an illustrative series Interv. Neuroradiol. 2023 15910199231216759 10.1177/15910199231216759
18 Kroszczynski A.C. Kohan K. Kurowski M. Olson T.R. Downie S.A. Intraforaminal location of thoracolumbar anterior medullary arteries Pain Med. (Malden, Mass) 14 6 2013 808 812
