Klinische Neuroradiologie © Urban & Vogel 2000
2000;10:161–5, Nr. 4, Dezember
Spinal Cord and Spinal Dural Arteriovenous Fistulas and Intradural Calcification Case Report Matti Porras1, Seppo Juvela2
Abstract: A patient had 3 episodes of spinal subarachnoid hemorrhage over 23 years and after that a perimedullary arteriovenous fistula (AVF) at the L2 level was detected fed by the anterior spinal artery which filled via the radiculomedullary artery from the right T9 intercostal artery. Large dilated veins drained mainly caudalward. Also intradural calcification was seen on CT at the L4 level. The fistula was embolized successfully. Control MR angiographies taken 4 and 8 months later had a lumbar intradural vessel which resembled the main draining vein of the spinal cord AVF, but was smaller. Spinal angiogram then showed that the spinal cord arteriovenous fistula was still occluded but at the L4 level there was a dural arteriovenous fistula fed by the left L4 lumbar artery, which was not formerly examined. The fistula drained cranialward via the same vein which had drained the spinal cord fistula caudalward but the vein was much smaller now. The fistula was at the same region as the calcification seen on CT. Key Words: Spinal cord arteriovenous fistula · Dural arteriovenous fistula · Spinal calcification Perimedulläre und durale arteriovenöse Fisteln und intradurale Verkalkung. Fallbericht Zusammenfassung: Nach drei spinalen Subarachnoidalblutungen im Verlauf von 23 Jahren wurde bei einer Patientin eine perimedulläre arteriovenöse Fistel (AVF) in Höhe des zweiten Lumbalwirbels diagnostiziert. Die Fistel wurde arteriell über die Arteria spinalis anterior aus der neunten Interkostalarterie rechts versorgt; die venöse Drainage erfolgte bevorzugt nach kaudal. Im CT fanden sich zusätzlich intraspinale Verkalkungen in Höhe L4. Die Fistel wurde erfolgreich embolisiert. Bei Kontroll-MR-Angiographien vier und acht Monate später fand sich ein intradurales Blutgefäß, das wie die Hauptdrainagevene der embolisierten perimedullären Fistel aussah, jedoch im Diameter abgenommen hatte. Eine erneute Spinalangiographie wies nach, dass die perimedulläre Fistel komplett verschlossen war; aber es fand sich nun eine durale AVF in Höhe des vierten Lumbalwirbels. Diese durale Fistel wurde jetzt in kranialer Richtung über die ehemals die perimedulläre Fistel drainierende Vene drainiert. Die durale Fistel war dabei in Höhe der in der CT nachgewiesenen intraspinalen Verkalkung lokalisiert. Schlüsselwörter: Spinale perimedulläre Fistel · Durale arteriovenöse Fistel · Intraspinale durale Verkalkungen 1 2
Department of Radiology, Department of Neurosurgery, Helsinki University Central Hospital, Helsinki, Finland.
Submitted: 28 Aug 2000; accepted 15 Sept 2000.
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pinal vascular malformations are rare lesions. They are classified into dural arteriovenous fistulas (AVF) (35%), spinal cord arteriovenous malformations (59%) and metameric arteriovenous malformations (6%). Spinal cord AVF is a subgroup of spinal cord arteriovenous malformations: of these about 19% are AVFs and the rest true arteriovenous malformations [1].
perimedullary AVF at the L2 level. The only feeding artery was the anterior spinal artery which ended at the fistula. This artery filled via the radiculomedullary artery from the right T9 intercostal artery. Its veins drained mainly caudalward and the lowest vein loop was at L4 level (Figures 2a and 2b). The fistula was successfully embolized with n-butylcyanoacrylate. After that the paraparesis partially improved. Control MR examinations 4 and 8 months later showed that the large spinal canal vessels had disappeared, but on MR angiography there was an abnormal lumbar intradural vessel which resembled the draining vein of the former spinal cord AVF, but was smaller. A new spinal angiography showed that the perimedullary AVF was still totally occluded, but from the left L4 lumbar artery filled via small branches a dural AVF at the L4 level from which a vein drained cranialward (Figures 3a and 3b). The vein was the same vessel seen on MR angiography and also the same one which had drained the spinal cord AVF, but it was smaller now and the flow was in the opposite direction. The patient refused the offer of further treatment.
Plain X-ray and CT findings are normal in these diseases and the diagnosis is nowadays made with MR imaging and confirmed with spinal angiography. We present here a patient who had a spinal cord AVF at the L2 level and dural AVF at the L4 level. In addition there was intradural calcification at the L4 level as seen on CT examination. Case Report A 46-year-old woman had 3 episodes of spinal subarachnoid hemorrhage over 23 years. No radiological spinal examinations had been done nor any surgical operations. After the last hemorrhage she had worsening paraparesis and lower extremity pains. Lumbar CT examination without contrast medium showed intradural calcification at the L4 level (Figure 1). On MR imaging large vessels were seen in the spinal canal from the lower thoracic to the L4 level. Spinal angiography was done and intercostal and lumbar arteries from T6 to L3 were examined. The angiogram revealed an intradural
Discussion The presented patient had 2 lumbar spinal AVFs, 1 perimedullary at the L2 level and the other dural at the L4 level. In addition she had intradural calcification at the L4 level. This combination led to the suspicion they all might have some causal relationship. Spinal vascular malformations are rare lesions and about 11% are spinal cord AVFs and 35% spinal dural AVFs [1]. All spinal vascular malformations typically produce a slowly progressive paraparesis. Subarachnoid hemorrhage with abrupt paraplegia is possible but not with spinal dural AVFs [8]. Plain X-ray and CT examinations are normal in cases of spinal AVFs. On myelography tortuous intradural vessels are usually seen but nowadays MR imaging is done which reveals pathological intradural vessels [4]. The final diagnosis is made with spinal angiography. This shows feeding arteries, the fistula and draining intradural veins [1]. Multiple AVFs may be present especially in cases of Rendy-Osler-Weber disease [7]. Our patient had no signs of this disease. It is possible that our patient had 2 incidental AVFs but this does not explain the calcifications at the dural AVF site.
Figure 1 Noncontrast CT at L4 level shows intradural calcification.
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Calcifications in the spinal canal has been reported with calcified and thickened posterior longitudinal ligament [2], disc herniation, calcified neurinoma or meningeoma, teratoma and after arachnoiditis [3, 7], sarcoidosis [9] and pantopaque myelography [5]. The brain as well as visceral vascular malformations often have calcifications, but this has not been described in the spine [7].The intradural calcification at the L4 site can be explained as postarachnoiditic after 2 earlier
subarachnoid hemorrhages due to the perimedullary AVF at the L2 level. Spinal dural like other dural AVFs are considered acquired lesions. Perhaps arachnoiditic changes at L4 level have induced the formation of the dural AVF at the same site.
Figure 2a
Figure 2b
It is also possible that there had been thrombosis in a branch of the draining vein of the L2 spinal cord AVF. The calcification at L4 level may be postthrombotic
Figures 2a and 2b Perimedullary AVF at the L2 level. The feeding artery is the anterior spinal artery which filled via the right T9 intercostal artery (a). The veins drained mainly caudalward (b).
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like phleboliths in other parts of the body, especially in pelvic veins. Perhaps the dural AVF at L4 level then developed as an effort to recanalize the thrombosed vein [6]. The dural AVF drained into the same vein as the former spinal cord AVF because this was the main venous channel in the lumbar area. It is probable that the dural AVF also existed when the spinal cord AVF was still open because the calcification at the L4 level was then seen and because the dural AVF was seen already 4 months after the occlusion of the perimedullary fistula but this cannot be proved because the L4 lumbar artery was not examined during the first spinal angiogram when the spinal cord AVF was detected. It is, however, possible that the dural AVF would not have filled then because the
venous pressure in their common draining vein was high and against the direction of the flow of the dural AVF.
Figure 3a
Figure 3b
In summary, the pathogenesis is perhaps the following: Our patient had 3 subarachnoid hemorrhages because of the spinal cord AVF at the L2 level over 23 years. Then arachnoiditis due to the former hemorrhages or thrombosis in branches of the draining vein developed and caused calcification at the L4 level. The dural AVF at the L4 level developed as a reaction to inflammatory or thrombotic changes. The dural AVF drained into the same vein as the former, embolized spinal cord AVF because this was the main or the only venous channel in the lumbar region.
Figures 3a and 3b Spinal angiography about 8 months later shows dural AVF at the L4 level. The feeding artery was the left L4 lumbar artery and the vein drained cranialward. The vein was the same one which had drained the spinal cord AVF. Arterial phase (a), and venous phase (b).
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7. Osborn AG. Diagnostic neuroradiology. St. Louis, Missouri: Mosby-Year Book, Inc, 1994:830–67. 8. Shephard RH. Spinal arteriovenous malformations and subarachnoid haemorrhage. Br J Neurosurg 1992;6:5–12. 9. Waubant E, Manelfe C, Bonafé A, et al. MRI of intramedullary sarcoidosis: a follow-up of a case. Neuroradiology 1997;39: 357–60.
References 1. Berenstein A, Lasjaunias P. Endovascular treatment of spine and spinal cord lesions. In: Surgical neuroangiography, Vol V. Berlin: Springer, 1992:1–85. 2. Burgener FA, Kormano M. Differential diagnosis in computed tomography. Stuttgart–New York: Thieme, 1996:120–41. 3. Gonzales CF, Grossman CB, Masden JC. Head and spine imaging. New York: John Wiley & Sons, 1985:781–855. 4. Malsalchi M, Bianchi MC, Quilici N, et al. MR angiography of spinal vascular malformations. AJNR 1995;16:289–97. 5. Manelfe C. Imaging of the spine and spinal cord. New York: Raven Press, 1992:257–332. 6. Mironov A. Classification of spontaneous dural arteriovenous fistulas with regard to their pathogenesis. Acta Radiol 1995;36: 582–92.
Address for Correspondence: Matti Porras MD, Department of Radiology, Töölö Hospital, Helsinki University Central Hospital, POBox 266, FIN-00029 Hus, Finland, Phone (+358/9) 47187-342, Fax -348, e-mail:
[email protected]
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