[Pain after sympathectomy].

Surgical sympathectomies and chemical sympatholyses bring about a true sympathetic deafferentation. This leads to central retrograde degenerescence reactions of the pre-ganglionic neurons, to a reduction of the muscular tone and to a secondary neurovascular disorder at the edge of the sympathetic denervation zone. In a limited number of cases, a radiculalgia-like functional painful syndrome may develop. There are variations in the degree of seriousness and evolution, but the outcome is always spontaneously favourable. Forty seven cases of radiculalgias are reported; the onset is sudden, most often at night, and the untoward effects gradually wear off with the recovery of some degree of peripheral vasomotor tone. Although classical antalgic therapies do not seem to affect the spontaneous evolution of this syndrome, the use of membrane stabilizers such as nifedipine does however induce an immediate functional improvement of the neurovascular disorders. This leads to a dramatic sedation of the pain, provided calcium inhibitors were not administered prior to the sympathectomy.