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Paper title Perimedullary arteriovenous fistulas: Clinical presentation and imaging findings in regard to flow pattern in 32 patients
Paper code P34
  1. Amgad El Mekabaty Inselspital, Universitätsspital Bern Speaker
  2. Philippe Gailloud The Johns Hopkins Hospital
Form of presentation Poster
  • Joint SSNR | SSNS
Abstract text Introduction:
Perimedullary arteriovenous fistulas (PmAVF) were identified as a distinct entity by Djindjian et al and further characterized by J.J. Merland et al in 1980, who divided them into Types I, II, and III (i.e. Merland Classification). It is often assumed that the three types of PmAVFs represent a pathological continuum and characterize identical lesions seen at various stages of evolution, but differences in presentation seem to indicate otherwise. In this analysis of PmAVFs we aim to examine the hypothesis that Type I lesions represent a separate group from Type II and III, with distinctive demographic, modes of presentation and etiology.
The retrospective analysis disclosed 38 patients with the angiographic diagnosis of PmAVF seen in our service between January 2000 and March 2017. Full angiographic documentation was only available in 33 patients. SpDSA was analyzed for the following; Merland classification, flow pattern (high-flow vs. low-flow), arterial feeder side, number of feeding arteries, level of feeding artery origin, level of arteriovenous shunt, location on the surface of the spinal cord and spinal venous hypertension. MRI was examined for T2 abnormalities, T2 flow voids, cord parenchymal enhancement and SAH.
We reviewed SpDSA in 33 patients with an average age of 38.8 years (SD 24, range 0.2-80), 19 (58%) males and 14 (42%) females. Fourteen (14/30, 47%) patients presented with chronic symptoms, 12/30 (39%) patients presented subacutely (5 patients had SAH) and 4/30 (14%) were asymptomatic. Three (9%) patients had a total of 4 PmAVF lesions at the craniocervical junction. Clinical presentation with sphincter disorder was often observed in Type I (80%) than Type II (43%) and Type III (11%), p=0.007 and SAH was predominantly present in Type II and III (30% and 22%, respectively) compared with Type I (0%). Type I lesions were not observed in the cervical region compared with Type II (33%) and III (20%). Spinal venous hypertension was often present in Type I lesions (91%) compared with Type II (25%) and III (20%), p < 0.001. On MRI, both extensive T2 cord signal abnormality and T2 flow voids were significantly different between Type I (100% and 44%) compared to Type II (25% and 88%) and III lesions (22% and 100%), p=0.005 and 0.014, resp.
In our cohort, we observed that type I PmAVF differ in clinical presentation, angiographic and MR findings from type II and III, which correlated well with flow pattern.