脊髓血管畸形课件_3

Spinal Vascular Malformations Typical and Atypical Findings Contents Introduction Classification however, they all have a limited territory related to the radiculomeningeal artery. All radiculomedullary arteries enter the spinal canal via the nerve roots . Classification however, an acute 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 venous pressure arteriovenous pressure gradient drainage of normal spinal veins venous congestion with intramedullary edema (usually lower cord and conus) chronic hypoxia and progressive myelopathy Spinal dural arteriovenous fistulae (SDAVF) are the most often encountered spinal vascular malformations and account for approximately 70 % of all AV shunts of the spine. locationmechanism SDAVF misdiagnosedsymptom 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. Contrast 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 spinal 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 exception 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. Success rates: 25-75%. 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 between 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). Selective 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 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 arteriovenous 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) 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 angiography 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 radicular 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 demonstrates 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 level 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 angiography 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 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 Arteriovenous 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 cervical 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 operation 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 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 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 foramen 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 revealed 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 demonstrate 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 differs 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 the (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 Cord AVMs the most commonly encountered characterized by an angioma nidus location: on the surface or deep within the cord parenchyma or extend to both compartments supplied by several arteries or branches originate from the A or P arterial feeding system Glomerular AVMs (plexiform or nidus-type AVMs) direct arteriovenous shunts located superficially and only rarely possess intramedullary compartments Feeding vessels are again radiculomedullary arteries Further categorized: a low shunt volume, only moderately enlarged feeding veins and arteries, a high shunt volume Fistulous AVMs (AVMs of the perimedullary fistula type or intradural AV fistulae) Spinal Cord AVMs are fed by radicullomedullary. Spinal Cord AVMs are fed by radicullomedullary. Location: intra- and/or perimedullary.Location: intra- and/or perimedullary. Differentiated according to their transition(A. V.)Differentiated according to their transition(A. V.) Spinal Cord Arteriovenous Malformations The symptoms and neurological deficits which lead to the The symptoms and neurological deficits which lead to the diagnosis can be explained by different pathomechanisms:diagnosis can be explained by different pathomechanisms: Venous congestion: chronic and progressive myelopathy Venous congestion: chronic and progressive myelopathy including pain;including pain; Local space-occupying effect of the AVM: enlarged venous Local space-occupying effect of the AVM: enlarged venous pouches and massively dilated feeding arteries and draining pouches and massively dilated feeding arteries and draining veins, deficits can be present;veins, deficits can be present; Intramedullary and subarachnoid hemorrhages: acute Intramedullary and subarachnoid hemorrhages: acute neurological deficits or chronic symptoms;neurological deficits or chronic symptoms; Steal-effect seems to play a minor or no role.Steal-effect seems to play a minor or no role. Compared to spinal dural AV fistulae, spinal AVMs tend to get Compared to spinal dural AV fistulae, spinal AVMs tend to get symptomatic in younger children and adolescents.symptomatic in 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 exact 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 location 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. Surgery: In slow flow perimedullary fistulas that are fed by dorsolateral arteries, might be alternative to above methode. When the treatment is needed? l Those have already bled tend to rebleed again because of specific angiomorphological features (such as associated false aneurysms) and should therefore prompt treatment. l 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 patient 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 (arrowhead,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 ectasia 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 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. Spinal Cord Arteriovenous Malformations Fig. 7 Glomerular AVM. This 25-yr-old woman had complained of electrifying dysesthesia in her right leg for 11 years. In the past months the symptoms were progressive and also involved the left leg. MRI was suspicious for a glomerular AVM at the Th11 level (A). The following spinal angiography showed a glomerular AVM which was mainly supplied by a posterior- lateral artery at Th11 (B). Since a safe intranidal position of the catheter could not be achieved owing to the small caliber of the feeding artery, particle embolization was performed. The AVM could be successfully occluded and demonstrated stable results on one year follow-up (C) in a neurologically intact patient whose symptoms had completely resolved following treatment. Spinal Cord Arteriovenous Malformations Fig. 8 Concurrence of a glomerular and a fistulous AVM.This 36-yr-old male, suffered from slowly progressive gait disturbances for about five years. In the neurological examination he presented with severe ataxia that made him unable to walk without help. There was no bowel-bladder dysfunction. MRI (T1 after contrast enhancement) demonstrated cord edema and a conglomerate of dilated perimedullary veins. An intramedullary nidus was located lateral to the spinal cord at Th12. Glomerular AVM at TH12 could be identified as being fed by the anterior spinal artery that arose from Th9 and from a dorsolateral artery arising from L2 (arrowhead in A + C). Perimedullary fistula that was located at L1 with the fistulous zone clearly separated from the glomerular AVM could be visualized (arrow in A + C) Both malformations could be successfully occluded during the same endovascular session. At discharge the patient s neurological status had improved. This case report underlines that, using MRI alone, the type of AVM can not be differentiated; instead, selective arterial angiography is necessary. Cavernomas Spinal cord cavernomas (or cavernous malformation) are estimated to constitute 5% of all spinal vascular malformations. Gross pathology Microscopy discrete, lobulated, well- circumscribed, red to purple raspberry-like lesions. composed of dilated, thin-walled capillaries (simple endothelial lining with variably thin fibrous adventitia) MRI well-defined, varying sizes, circumscribed, have a hypointense rim and an inhomogeneous, often hyperintense center on T2. Zevgaridis described a clinical course with acute deterioration in 26% , with gradual or intermittent worsening in 30% and slowly progressive development of symptoms in 41% of their cases. Cavernomas are angiographically silent. In acutely hemorrhaged cavernomas, however, spinal angiography may be performed to rule out a small glomerular AVM that might go unnoticed on spinal MRI. Although not stated explicitly in the literature, the rebleeding rate of those cavernomas that have already bled is supposed to be higher than 10%. In these cases, we feel that treatment is therefore necessary. The method of choice is microsurgical resection. Cavernomas Cavernomas Fig. 9 Spinal cord cavernoma. MRI of this 40-yr-old w