We have a lovely dog we all adore, but she has a health issue; every so often - about every three-four months - her back legs stop working properly. She doesn't lose all power in them, but she struggles to get around. Steroids make her better, but only temporarily. This has been going on for over a year. Anyone know anything about this? It's like a doggie MS. She's otherwise very healthy. The vet doesn't know anything much about it, and she - the dog - has had an MRI scan with no result.