Pain in peripheral neuropathy related to rate and kind of fiber degeneration.

In a series of 72 patients with disease of peripheral neurons, neuropathic painfulness of the foot was found to be related to the rate and kind of nerve fiber degeneration. Patients with acute breakdown of myelinated fibers (either by wallerian or axonal degeneration) tend to have pain more often and to a greater degree than do patients with more chronic forms of nerve fiber degeneration. Neuropathic painfulness was not found to be related simply to the ratio of remaining large and small fibers after nerve fiber degeneration. These studies do not fit the expectation of the proponents of the gate theory of pain.