1. Left posterior spinal artery stroke following ipsilateral vertebral artery dissection Dirk Ulbricht, Michel Kruger Service de Neurologie, Centre Hospitalier Emile Mayrisch, Esch-sur-Alzette, Luxembourg Introduction: Ischemic stroke of the spinal cord is rare outside the setting of aortic surgery. Posterior spinal artery (PSA) stroke is very rare, and presents with signs of the posterior cord, leading to sensory loss in the affected segment and below, and little motor and bladder dysfunction. Case report: a 48 year-old man was admitted for dysesthesia of the distal extremities in a stock- and-gloving pattern and unsteady gait. Tactile and pain sensation were slightly diminished and position and vibration sense were abolished, much more on the left than on the right body half, without clear segmental level. Tendon reflexes were exaggerated, Claus ﾕ sign was positive the left, and there was slight distal paresis of his left hand and foot and urinary retention. He had left painless Horner’s syndrome, but no other pain. His past medical history was unremarkable but for inactive Bechterew’s disease. Technical work-up was normal except for cervical magnetic resonance imaging demonstrating high signal in T2-weighted imaging in the left posterolateral spinal cord reaching from level C2-7. There was hyperintensity in the wall of the vertebral artery confirming dissection with preserved flow on Doppler ultrasound. A tetraparesis was transient, but crurally accentuated left sensory ataxia with central pain, and urinary retention persisted. Three months after, the patient was able to walk without aid, and was devoid of urinary trouble, but kept left sensory ataxia, and resumed his everyday activities. Discussion: this presentation of stroke in the PSA territory is unusual for several reasons: (1) the initial complaint of the patient was suggestive of infect-related acute polyneuritis or myelitis than (2) of vertebral artery dissection, which presented painless. The clue to vascular pathology was Horner ﾕ s syndrome. The probable mechanism of stroke was obstruction of the posterior spinal artery at its origin from the left vertebral artery by haematoma of the arterial wall. The short-term outcome was excellent. Key messages “Posterior spinal artery stroke is rare, but may occur”. In case of unilateral ataxia, PSA stroke should be considered as differential diagnosis PSA can mimic inflammatory cervical spine or root disease It might be that PSA stroke was underdiagnosed before the advent of MRI. Prognosis seems to be fairly good regarding everyday activities. References 1.Bergqvist CA, Goldberg HI, Thorarensen O, Bird SJ. Posterior cervical spinal cord infarction following bilateral vertebral artery dissection. Neurology 1997;48:1112-5. 2.Crum B, Mokri B, Fulgham J. Spinal manifestations of vertebral artery dissection. Neurology 2000;55: 304-6. 3.Fukuda H, Kitani M. Unilateral posterior spinal artery syndrome of the upper cervical cord associated with vertebral artery occlusion. Rinsho Shinkeigaku 1994;34:1171-4 (Abstract only). 4.Garnier P, Michel D, Peyron R, Beauchet O, Le Bras F, Barral FG. Isolated ischaemia of the spinal cord due to bilateral vertebral artery dissection. JNNP 1999;66:804. 5.Hundsberger T, Thömke F, Fitzek C, Hopf HC. Symmetrical infarction of the cervical spinal cord due to spontaneous bilateral vertebral artery dissection. Stroke 1998;29:1742. 6.Kaneki M, Inoue K, Shimizu T, Mannen T. Infarction of the unilateral posterior horn and lateral column of the spinal cord with sparing of posterior columns: demonstration by MRI. JNNP 1994;57: 629-31. 7.Mascalchi M, Cosottini M, Ferrito G, Salvi F, Nencini P, Quillici N. Posterior spinal artery infarct. AJNR 1998; 19: 361-3. 8.Mohr JP, Benavente O, Barnett HJM. Spinal cord ischemia. In: Mohr JP, Choi DW, Grotta JC, Weir B, Wolf PA (eds.): Stroke. Philadelphia 2004; pp. 423-36. 9.Sturzenegger M. Spinal stroke syndromes. In: Bogousslavsky J, Caplan LR (eds.): Stroke syndromes. Cambridge 2001, pp. 691-704. 10.Weidauer S, Gartenschläger M, Claus D. Spinal sulcal artery syndrome due to spontaneous bilateral vertebral artery dissection. JNNP 1999;67: 550-1. Introduction Ischemic stroke of the spinal cord is rare outside the setting of aortic disease. it mainly occurs in the territory of the anterior spinal artery, as the other territories are overlapping and thus have good collateralization. Stroke in the territory of the posterior spinal artery seems very rare and should present with posterior column and posterior horn signs, i.e. sensory loss below the affected segment, but few motor and vegetative signs. Case report A 48 year-old man was admitted for dysesthesia of the distal extremities in a stock-and-gloving pattern and unsteady gait. Tactile and pain sensation were slightly diminished and position and vibration sense were abolished, much more on the left than on the right body half, without clear segmental level. Tendon reflexes were exaggerated, Claus ﾕ sign was positive the left, and there was slight distal paresis of his left hand and foot and urinary retention. He had left painless Horner ﾕ s syndrome, and no other pain. His past medical history was unremarkable but for inactive Bechterew ﾕ s disease. The day of the event, he had undertaken an exhausting physical effort at work, and in the evening visited a China restaurant. Technical work-up (LP, Blood analysis) was normal except for cervical magnetic resonance imaging demonstrating high signal in T2-weighted imaging in the left posterolateral spinal cord reaching from level C2-7 (figure). There was hyperintensity in the wall of the vertebral artery (VA) confirming dissection with reduced flow on Doppler ultrasound. SEP were diminished in amplitude from the left extremities, but MEP were normal.A tetraparesis was transient, but crurally accentuated left sensory ataxia with central post-stroke-pain (CPSP), and urinary retention persisted. Eight months after, the patient was able to walk without aid, and was devoid of urinary trouble. He kept left sensory ataxia, distally accentuated CPSP and resumed his everyday activities.. Discussion Our patient presented unilateral sensory ataxia together with Horner’s syndrome. MRI disclosed lesions of the posterolateral cervical spine ranging from C3-7 together with an irregular ipsilateral vertebral artery suggesting dissection with consecutive posterior spinal artery stroke. Little is to be drawn from the literature on the occurrence and outcome of PSA stroke. There have been several case reports linking cervical spinal ischemia to VA dissection, mostly evoking local haematoma occluding the PSA at its origin. In our case, however, the dissection seems to be localized more proximal leading to patchy lesions and probable embolic stroke with reduced compensation by local collaterals. The outcome was dominated by sensory left- sided ataxia along with CPSP, thus setting the syndrome clearly apart from other types of spinal cord ischemia. He was able to resume nearly all of his daily activities. Figure: Upper row: sagittal T2-weighted images disclosing patchy lesions ranging from C3-7. Second row: coronal T2-weighted images, left side anterior with normal signal, right posterior with hyperintensity on the right. Third row: axial sections with demonstration of hyperintensity in the posterolateral quadrant of the cervical cord along with dimnuished flow signal in the VA (white arrow) and parts suggestive of wall hematoma (yellow arrow). Lower row: MRA of the vertebral arteries demonstrating regular wall on the right (left image), and irregular narrowing on the left (right image). <-