Internodal length of sural nerve fibres in chronic occlusive vascular disease.

Changes with age in internodal length in the sural nerve in man have been discussed by Lascelles and Thomas (1966). They reported their findings in the sural nerve obtained at necropsy in 14 subjects of ages ranging from 18 to 80 years. In the 10 subjects under the age of 65 years the correlation between internodal length and the maximum diameter of single nerve fibres was found to be close, especially in the younger subjects. In the other four subjects (aged 68, 73, 74, and 80 years) there were abnormally short internodal lengths, which on analysis were considered to result mainly from segmental demyelination and remyelination and also regeneration after complete degeneration of the fibres. Lascelles and Thomas considered ischaemia secondary to occlusive disease of the vasa nervorum as a possible explanation of these degenerative changes occurring in peripheral nerve fibres in later life. In the present study the sural nerve has been examined in six patients with severe occlusive vascular disease in the legs, of whom three were in the relatively young, under-50, age group. The series provided an opportunity of considering the effects of ischaemia as the main or only pathological factor damaging the nerve.