Spinal cord stimulation in deafferentation pain.

Spinal cord stimulation (SCS) was used in 49 cases to control resistant deafferentation pain resulting from causalgia, phantom limb, plexus and nerve root avulsion, postherpetic neuralgia, reflex sympathetic dystrophy and amputation. In all cases, one or two standard percutaneous leads were introduced into the epidural space and manipulated until the spinal segment at which external stimulation provoked paresthesic sensation in the painful area. Two weeks of external stimulation trial was used to determine the efficiency of the system. Pulse width of 0.1-0.2 ms, a rate of 80-120 cps and amplitude to low paresthesia threshold were programmed as electric parameters. In 36 out of the 49 tested cases showing a positive response to percutaneous SCS, the device was permanently implanted. After a mean follow-up of 5.5 years, 57% of patients had satisfactory pain relief (over 75%). Side effects were limited to dislodgement of the electrode in 1 case and wire extrusion in another, both requiring replacement of the stimulator.