Chronic motor cortex stimulation for phantom limb pain: correlations between pain relief and functional imaging studies.

Chronic motor cortex stimulation (CMCS) has provided satisfactory control of pain in patients with central or trigeminal neuropathic pain. We used this technique in 3 patients with intractable phantom limb pain after upper limb amputation. Functional magnetic resonance imaging (fMRI) correlated to anatomical MRI permitted frameless image guidance for electrode placement. Pain control was obtained for all the patients initially and the relief was stable in 2 of the 3 patients at 2 year follow-up. CMCS can be used to relieve phantom limb pain. fMRI data are useful in assisting the neurosurgeon in electrode placement for this indication.

[Treatment of spasticity with the intrathecal administration of baclofen]. / Traitement de la spasticité par administration intra-thécale chronique de baclofène.

Direct intrathecal administration of baclofen in the treatment of severe spasticity was proposed in 1984 by Richard Penn with the objective to carry out a selective spinal distribution of the active principle thus avoiding supraspinal side effects. We presented our first results at the French Language Association of Neurosurgery in 1985 within the framework of a report on "Functional neurosurgery of cerebral palsy" (Neurochirurgie, 1985, 31 (suppl 1): 1-118). This study aims to specify the selection criteria and current indications of this method for the treatment of severe chronic diffused spasticity of spinal and cerebral origin in adults and in children. This report relates to our experience concerning 60 patients (10 children) that benefit from the use of a totally implantable system for chronic administration. The total follow-up of all patients was 48 months (from 3 to 140 months). The initial effective daily amount of baclofen was 156 micrograms/24 hours and progressed in time to reach in the long run 280 micrograms/24 hours, with a very broad interindividual variability from 36 to 1050 micrograms/24 hours. All the patients benefited from a reduction in muscular hypertonicity as well as painful muscular spasms. On the other hand, the functional improvement was very variable from one patient to another and depended primarily on the initial clinical state and the etiology of the spasticity. The results observed were more significant in post-traumatic paraplegia than those secondary to demyelination disease even if they were stabilized with regard to spasticity of spinal origin. This mode of administration currently plays a significant role in the treatment of spasticity of cerebral origin, in particular in children presenting a motor disorder of cerebral origin with spastic prevalence. The current limitations of this type of treatment are technical because of the frequent catheter malfunctions, but are due essentially to the importance and constraint of the multi-disciplinary organization needed for the out-patient follow-up.

[Chronic spinal cord stimulation in the treatment of neurogenic pain. Cooperative and retrospective study on 20 years of follow-up]. / La stimulation médullaire chronique dans le traitement des douleurs neurogènes. Etude coopérative et rétrospective sur 20 ans de suivi.

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.