Transient pelvic limb neuropathy following proximal metatarsal and tarsal magnetic resonance imaging in seven horses

BACKGROUND: Pelvic limb neuropathy is a rare post-anaesthetic complication. In the authors' experiences, the incidence of post-anaesthesia neuropathy is increased following MRI of the proximal metatarsus and tarsal regions when compared with previously reported incidences of post-anaesthetic neuropathy. OBJECTIVES: This study reports the incidence, diagnosis, treatment and outcome of seven horses with post-anaesthesia neuropathy following proximal metatarsal and tarsal MRI. STUDY DESIGN: Retrospective case series. METHODS: Case record review of horses receiving general anaesthesia for MRI between 1 January 2012 and 31 December 2017. RESULTS: A total of 1134 MRI procedures were performed and reviewed for analysis. Eight cases of neuropathy were identified in 1088 limb scans (0.74%). Of these cases, one was subsequent to thoracic limb imaging (1/834; 0.12%) and seven were subsequent to imaging of proximal metatarsal and/or tarsal structures (7/181; 3.9%). Following proximal metatarsal and/or tarsal MRI, transient nondependent limb femoral neuropathy developed in six of the seven affected horses, with one additional horse developing peroneal neuropathy of the dependent limb. Recovery of pelvic limb function occurred within 72 h and 9 days in six and one horse, respectively. MAIN LIMITATIONS: Anaesthetic protocol and neuropathy treatment for the affected horses were not standardised. CONCLUSIONS: Though an uncommon complication in horses, transient neuropathy may occur more frequently following MRI of the proximal metatarsal and tarsal structures when compared with other MRI scans. This may be due to patient positioning and the requirement for limb traction for MRI of more proximal regions. Supportive care facilitates rapid return to function.