[Chronic spinal cord stimulation in the treatment of neurogenic pain. Cooperative and retrospective study on 20 years of follow-up].

The aim of this investigation is to evaluate the long-term spinal cord stimulation (SCS) efficacy and safety, with a 20-years study concerning 692 patients (series I: 279, series II: 413). The series concern 304 arachno-epidural fibrosis, 152 peripheral nerve lesions, 25 amputations pain, 17 plexus brachial lesions, 101 spinal cord lesions, 22 cancer pain, and 71 vascular pain. A multidisciplinary chronic pain evaluation must exclude contra-indications (nociceptive pain, serious drug habituations, psychological problems, unresolved issues or secondary pain). Percutaneous epidural SCS is a screening method if the trial is sufficiently prolonged (3 to 14 days) and if the pain topography is overlapped by induced paresthesias. The immediate global results of the 2 series are similar: respectively 86% and 85% of success one month after implantation. With the same longterm follow-up (mean: 10 yrs, range: 2-20), and the same evaluation criteria, the percentage of long-term global success rate is 54% in series I, and 52% in series II. In the most recent period (1984-1990) concerning 301 patients, the success rate are respectively 68% and 60%. Analysing the results etiologically confirms the therapeutic value of SCS for neurogenic pain secondary to partial deafferentation. For upper limb pain, ipsilateral radicular stimulation is preferable. When the nerve lesion extends to the pre-ganglionic portion (brachial plexus avulsion, herpes zoster) or in cases of pain of spinal or cerebral origin, thalamic stimulation must be considered, after failure of SCS.