Abstract: ObjectiveTo investigate the pathologic characteristics of the sural nerve in amyotrophic lateral sclerosis. MethodsClinical, electrophysiologic, laboratory data and sural nerve biopsy of 11 patients were reviewed. The clinical and laboratory data were compatible with the diagnosis of ALS. The sural nerve was removed and immediately fixed in 10% formalin and phosphate-buffered 2.5% glutaraldehyde and processed according to the procedure used in our laboratory for light and ultrastructural examination.Results4 groups were distinguished based on pathologic changes: normal; with mild axon degeneration and demyelination; with mild loss of the myelinated nerve, axon degeneration and demyelination; with severe loss of the myelinated nerve, axon degeneration and demyelination.ConclusionPredominantly axonal neuropathies are common and occur early in ALS. Axon degeneration of the nerve fibers is predominant, and demyelination also can be performed in patients with ALS.

Key words: amyotrophic lateral sclerosis, peripheral nerve, pathology, biopsy