[Pain following traumatic lesions of the brachial plexus (radicular avulsions and truncular lesions)].

Pain in avulsions lesions of the brachial plexus is related with deafferentation; experimental studies demonstrate that spontaneous discharges can be recorded with micro electrodes in the dorsal horn, after division of the dorsal roots. These discharges ("firing") are related with the loss of control of the inhibitory effects of the large caliber sensory fibers. This pathophysiological concept drawn from the Melzack and Wall's theory (gate control) allows a good meaning of the paradoxical results observed after neurotization (via accessory or intercostal nerves), namely immediate relief of pain, observed in several cases after surgery. This theory helps to explain the efficiency of the neurostimulation techniques (by inhibition of the "firing") and of the technique of "dorsal root entry zone coagulation" in the avulsed area, on the spinal cord, by direct destruction of the hyperactive cells in the posterior horn. These technical advances and early return to work and to community offer the best prospect of relief of pain. Incidence of intractable pain problem is less than 10% after 10 years.