South African Equine Veterinary Association Congress 2015 Protea Hotel Stellenbosch
studies, variation between and within observers and day-to day variation in horses (Perkins et al.
2009) and within surgical treatment of affected cases and animals that are lost to follow up.
Histopathological changes within the distal nerves of horses with RLN reveal collapsed myelin
sheaths, increased relative myelin sheath thickness, regenerating Schwann cell membrane clusters
(Bungner‟s bands) and „onion-bulb‟ formations indicative of demyelination and remyelination
(Cahill and Goulden 1986, Duncan 1978) thought to be collectively indicative of a primary
axonopathy with secondary myelin loss. More specific indicators of a primary axonopathy are the
central axon fragments commonly seen within myelin digesting chambers, accumulation of
axoplasmic organelles and margination of axonal microtubules (Cahill and Goulden
1986c)(Duncan and Hammang 1987). Such defects are seen in human neuropathies with
suspected axonal transport defects and given that nerve cell body pathology (in the nucleus
ambiguous) is not found in RLN-affected horses