1、Spinal Vascular Malformations Typical and Atypical Findings,Contents,Introduction,Spinal vascular malformations are rare and still under-diagnosed entities which, if not treated properly, can lead to considerable morbidity with progressive spinal cord symptoms and myelopathy.Initial symptoms: acute
2、onset of symptoms: intramedullary or subarachnoidal hemorrhages unspecific initial neurological symptoms: venous congestion with chronic myelopathy. Render an early diagnosis difficult.,Introduction,potential therapeutic approaches,“ classical ” spinal vascular malformations,some atypical findings,r
3、emind both the neuroradiologist and the referring physician that the diagnosis and subsequent treatment of these treatable causes of severe and otherwise progressive neurological deficits still remains challenging.,Classification & Vessel Anatomy,In this article we use a classification that is simil
4、ar to the one employed for vascular malformations of the brain.inborn lesions:arteriovenous malformations (AVM) cavernomas acquired lesions: dural arteriovenous (AV) fistulaeSince the classification outlined above relies heavily on vessel anatomy, we will briefly describe the salient features of the
5、 spine and spinal cord vascular supply.,Classification & Vessel Anatomy,Like their cerebral counterparts, malformations that are fed by arteries normally supplying the neural tissue.,sulcal arteries: supplying mainly the grey matter and the central parts, originate from the anterior spinal artery (A
6、SA)perforating pial arteries: derived from the vasocorona that supply the periphery of the spinal cord, i.e. mainly the white matter, that are fed by the dorsolateral arteries and small branches from the ASA (a)&(b) constitute a superficial longitudinal anastomosing system,Classification & Vessel An
7、atomy,ASA: typically originates from the two vertebral Arteries, travels along the anterior sulcus Posterolateral spinal arteries (paired): originate from the preatlantal part of the vertebral artery or from the postero-inferior cerebellar artery (PICA).These three arteries are not capable of feedin
8、g the entire spinal cord. Instead, they are reinforced at various (and unpredictable!) segmental levels by anterior (radiculomedullary) and posterolateral (radiculopial) arteries, the most well known of them being the arteria radiculomedullaris magna or Adamkiewicz artery .,Classification & Vessel A
9、natomy,Hairpin curve: Radiculomedullary arteries branch in a very typical way once they have reached the midline of the spinal cord into an ascending branch and a descending branch, the latter being the larger one at the thoracolumbar levels and forms a hairpin curve as soon as it reaches the midlin
10、e at the entrance of the anterior fissure. In the adult patient, not all lumbar or intercostal segmental arteries have a radiculomedullary feeder; however, they all have a limited territory related to the radiculomeningeal artery. All radiculomedullary arteries enter the spinal canal via the nerve r
11、oots .,Classification & Vessel Anatomy,Dural Arteriovenous Fistulae,easily be misdiagnosed.degenerative disease, polyneuropathy, neoplasms, or infections. Only a careful analysis of non-invasive imaging studies will result in the correct diagnosis.,Most in thoracolumbar region The arteriovenous shun
12、t: the dura mater of a proximal root sleeve, pedicle (radiculomeningeal artery enters a radicular vein).,Hypo-/paresthesias, progressive paraparesis, back pain that can irradiate to the lower legs, impotence, and sphincter disturbances. Usually, the deficits are slowly progressive; however, an acute
13、 onset of disease and a progressive development interrupted by intermediate remissions is also possible. Without therapy, this lesion results in irreversible para- or even tetraplegia.,Spinal dural arteriovenous fistulae (SDAVF) are the most often encountered spinal vascular malformations and accoun
14、t for approximately 70 % of all AV shunts of the spine.,Dural Arteriovenous Fistulae,The characteristic findings on MRI: Cord edema + Perimedullary dilated vessels Cord edema: centromedullary, On T2, not well delineated hyperintensity over multiple segments, often accompanied by a hypointense rim. C
15、ontrast enhancement chronic venous congestion. Perimedullary dilated vessels: typically seen on the T2 as flow voids. However, small volume shunt may only be seen after contrast enhancement. Contrast-enhanced time-resolved MRA might be helpful in locating the fistula before performing a selective sp
16、inal angiography. Spinal angiography Verify the exact height of the fistula and to rule out the fistulous type of low flow perimedullary arteriovenous malformations.,Dural Arteriovenous Fistulae,Treatment of SDAVF: 2 options Microsurgical treatment: is a fast, simple and definitive method with excep
17、tion of sacral fistulae and should aim at occluding the feeding arterial network and the proximal portion of the radicular vein. Success rates: above 95%. Endovascular therapy employing glue after superselective catheterization of the feeding radiculomeningeal artery must reach the same goal. Succes
18、s rates: 25-75%.,First Option,Dural Arteriovenous Fistulae,Fig. 1 Spinal dural AV fistula: This 74-yr-old male patient had a prolonged history of progressive gait disturbances, bowel-bladder incontinence and paraparesis.,The patient underwent microsurgery(frame C, arrow at the transition zone betwee
19、n artery and vein) and the fistula could be occluded as confirmed by postoperative spinal angiography. The patient s clinical status had improved by his clinical follow-up visit six months later.,On MRI: dilated perimedullary vessels (arrow) can be seen as flow voids. Cord edema (arrowhead). Selecti
20、ve spinal angiography revealed a dural fistula derived from the right Th10 segmental artery (frame B). The arrow points to the zone of fistulation underneath the pedicle.,Dural Arteriovenous Fistulae,Atypical findings:the following atypical findings of SDAVF in our experience with this disease based
21、 on more than 130 patients seen in our institution: delayed shunting from the epidural plexus into a radicular vein (Fig. 2); the concurrence of two separate dural AV fistulae(Fig. 3); dural AV fistulae at the level of the foramen magnum(Fig. 4); the concurrence of dural AV fistulae with arterioveno
22、us malformations of the fistulous type originating from a different segmental artery (Fig.5 ).,Dural Arteriovenous Fistulae,Fig. 2 Epidural AV fistula draining into a radicular vein: This 77-yr-old male patient was suffering from progressive gait disturbances for several months. MRI (T2TSE sequence)
23、 demonstrated findings typical for a dural AV fistula with cord edema and perimedullary enlarged veins (arrows in frame A).,Repeated spinal angiography at an outside institution was normal. On admission he was wheelchair-bound and had lost control of his bowel and bladder functions. During spinal an
24、giography an epidural fistula at the right L3 level was found.,Only after prolonged imaging (30 seconds) contrast media descended slowly down within the epidural plexus to the L4 level (arrows in frame B + C), crossed the midline and ascended to the L3 level where it then shunted into a left-sided r
25、adicular vein (frame D).,A surgical approach was undertaken aiming to occlude both shunts. Post-surgical angiography revealed occlusion of the shunt. At follow-up six months later, the patient had regained control over his bowel and bladder functions and was able to walk again.,This case demonstrate
26、s the need for prolonged imaging series in selected cases of suspected spinal dural AV fistulae.,Dural Arteriovenous Fistulae,Fig. 3 Double spinal dural AV fistulae:This 70-yr-old male patient with progressive paresthesia. Surgery with confirmed occlusion of the a dural AV fistula at the right L1 le
27、vel was performed in 1996. After initial regression of his symptoms, six years later he complained again of progressive weakness of his legs and bladder dysfunction.,MRI of the spinal axis showed a pathological vessel confirming the strong suspicion of a recurrent fistula (C). However, spinal angiog
28、raphy showed a complete occlusion of the right dural fistula at level L1. Angiography was continued and demonstrated a new dural fistula at the left L2 level (A + B).,Again, surgery was able to occlude this fistula and the patient s symptoms were again regressive during clinical follow-up.,This case
29、 underlines that once symptoms deteriorate again following occlusion of a spinal AV shunt, recurrence or a second pathology has to be sought for. Although exceedingly rare, (1 case in our series of more than 130 patients), a double dural AV fistula can be present in the same patient.,Dural Arteriove
30、nous Fistulae,Fig. 4 Dural fistula of the foramen magnum: This 49-yr-old male patient complained of gait disturbances and neck pain for two weeks. He underwent chiropractic maneuvers that relieved the pain; however, gait disturbances persisted, leading to further diagnostic work-up.,MRI of the cervi
31、cal spine revealed cord edema from C3 to C5 with a slight mass effect, suspicious for a tumor. No pathological vessels were seen. Symptoms during hospitalization were rapidly progressive (tetraplegia with respiratory insufficiency within 12 hours), and he was urgently operated upon.,During the opera
32、tion an arterialized vein on the surface of the spinal cord was detected, which was confirmed by intraoperative Doppler sonography. Emergency angiography was performed with the patient still under general anesthesia and revealed a dural fistula at the level of the foramen magnum (A + B).,The fistula
33、 was occluded successfully by microsurgical techniques. Postoperative angiography and MRI showed a complete obliteration of the fistula and regression of the cord edema, respectively. Symptoms gradually improved. However, incontinence, a slight paresis of his right arm and a paraparesis of his legs
34、persisted.,This case demonstrates that perimedullary vessels may be overlooked on imaging studies. Moreover, it highlights the fact that symptoms can be rapidly progressive in spinal cord vascular shunts,leading to emergency diagnostic and therapeutic procedures. Dural shunts at the level of the for
35、amen magnum are rare, in our series only three.,Dural Arteriovenous Fistulae,Fig. 5 Concurrence of a perimedullary fistula and a dural AV fistula: This 35-yr-old male patient suffered from progressive myelopathy and presented with both a dural AV fistula and an intradural perimedullary fistula as re
36、vealed during angiography and subsequent surgery.,Frame B and C show the selective spinal DSA after injection into the right Th6 intercostal artery that demonstrates a dural AV shunt with the shunt located directly beneath the pedicle, i.e. in the dural nerve root sleeve (arrow in B).,Frames D-F dem
37、onstrate the DSA after injection into the right T5 intercostal artery. Here a moderately enlarged dorsolateral radiculopial artery can be identified (arrow in D) that shunts perimedullary into perimedullary veins (arrowhead in E + F). Note that the venous drainage of the perimedullary fistula differ
38、s from the dural AV fistulae.,In the literature the frequency of double SDAVF is presumed to be around 2 % , while the combination of a dural and an intradural fistulae is exceedingly rare, with only two other reported cases. One might speculate whether the alteration in venous drainage caused by th
39、e (presumably inborn) perimedullary fistula could possibly promote the production of a second, dural fistula due to elevated pressure.,This case highlights the fact that one has to be aware of the occurrence of double pathology within the same patient.,Spinal Cord Arteriovenous Malformations,Spinal
40、Cord AVMs,Spinal Cord Arteriovenous Malformations,The symptoms and neurological deficits which lead to the diagnosis can be explained by different pathomechanisms: Venous congestion: chronic and progressive myelopathy including pain; Local space-occupying effect of the AVM: enlarged venous pouches a
41、nd massively dilated feeding arteries and draining veins, deficits can be present; Intramedullary and subarachnoid hemorrhages: acute neurological deficits or chronic symptoms; Steal-effect seems to play a minor or no role.Compared to spinal dural AV fistulae, spinal AVMs tend to get symptomatic in
42、younger children and adolescents.,Spinal Cord Arteriovenous Malformations,MRI: a conglomerate of dilated, peri- and intramedullary located vessels with flow voids; A venous congestive edema; additional intraparenchymal hemorrhages or subarachnoid hemorrhage. It can identify the location, but the exa
43、ct type of AVM can only seldom be identified using MRI alone. Selective spinal angiography:has to be performed for the correct diagnosis and treatment plan. 3D rotational acquisition and reconstruction angiography: provides a high-resolution 3D representation of spinal angioanatomy and the vessels l
44、ocation relative to spinal cord and surrounding structures.,Spinal Cord Arteriovenous Malformations,Endovascular embolization: - In glomerular AVMs, glue or particles can be employed to obliterate the nidus. Incomplete occlusion is often effective.- Fistulous AVMs can be treated by coils or glue. Su
45、rgery: In slow flow perimedullary fistulas that are fed by dorsolateral arteries, might be alternative to above methode.,When the treatment is needed?,Those have already bled tend to rebleed again because of specific angiomorphological features (such as associated false aneurysms) and should therefo
46、re prompt treatment.The therapeutic approach to asymptomatic AVMs is a matter of debate; Symptomatic AVMs should be treated since therapy ameliorates the prognosis.,Treatment methodes?,Spinal Cord Arteriovenous Malformations,Fig. 6 Perimedullary fistula with venous ectasia. This 27-yr-old male patie
47、nt experienced a spinal subarachnoid hemorrhage with acute stabbing back pain and paraparesis.,MRI revealed pathological vessels (A) while DSA revealed an AV perimedullary shunt that was fed by ASA from the right Th11 intercostal artery. The shunting zone (arrow, B), the further course of the ASA (a
48、rrowhead,B). 3D rotational angiography: exact location of the shunt and ASA (arrow, C) that was presumed to be responsible for the SAH (C).,A staged therapy was initiated: the microcatheter was occluding the ASA during therapy, first two detachable coils were introduced carefully into the venous ect
49、asia to allow for subsequent thrombosis.,3 weeks later, the shunt was still present, therefore an additional coiling procedure was performed until no further coils could be introduced without comprising the flow into the distal ASA (Frame C, the arrow points to the coils). Still revealed persistent
50、flow through the shunt.,6 weeks later, the shunt was completely obliterated with persisting flow through the distal ASA. The patient: normal neurological status and symptom-free with a follow-up at 1 year. D + E: stable occlusion of the fistula.,This case demonstrates that vascular remodeling and progressive thrombosis can occur following treatment and that, especially in low-fl ow shunts, a staged treatment may be the therapeutic option of choice.,
