Clinicoradiological range dissociation as a clue to spinal dural arteriovenous fistula

Background Spinal dural arteriovenous fistula (sdAVF) is treatable but may be overlooked when MRI shows a longitudinally extensive T2-hyperintense lesion without clear flow voids. We assessed whether mismatch between MRI lesion extent and bedside sensory mapping could prompt reconsideration of sdAVF. Methods We retrospectively analysed eight confirmed sdAVF cases from a consecutive single-centre cohort of 10 patients with spinal AVF between January 2013 and December 2024. Pretreatment MRI lesion and sensory deficit ranges were converted to myelomeres, and strength in selected bilateral lower limb muscles was summarised descriptively. Results MRI lesion range exceeded sensory deficit range in six of eight patients. Median MRI lesion length was 12.0 myelomeres (IQR 9.75–15.5) vs 6.0 myelomeres (IQR 3.5–8.5) for sensory deficit length; the median paired difference was 7.0 myelomeres (range −4 to 13). Despite long lesions, five of eight patients had total Medical Research Council scores of 26/30 or higher across selected bilateral lower limb muscles. Conclusions We observed clinicoradiological range dissociation in sdAVF. This finding may prompt reconsideration of sdAVF when the initial evaluation is inconclusive.