[Invasive techniques in chronic pain control]. / Les techniques invasives de contrôle de la douleur chronique.

A wide range of invasive techniques are available for pain treatment. Treatment must be adapted to the severity of the underlying disease and the intensity of pain. Very few controlled studies concerning these techniques have been performed, and it is therefore difficult to assess their short and long term efficacy. Optimal effectiveness will be obtained if the indication is correct. This non exhaustive revue presents the indications, techniques and results of neural conduction blocks as peripheral blocks, Alcock canal block, zygapophysial joint blocks and also central blocks illustrated by epidural and intrathecal injections and finally sympathetic nervous system blocks as celiac plexus block, stellate ganglion block and intravenous blocks for complex regional pain syndromes. The indications, techniques and results of thermal neurolyse (radiofrequency, thermocoagulation), transcutaneous electrical nervous stimulation (TENS) and implant central stimulation are also presented. A multidisciplinary approach is used to evaluate the risk/benefit ratio of these invasive techniques for each patient.

Low and high frequency stimulation tests to characterize the effects of edrophonium on vecuronium-induced neuromuscular block.

We recorded adductor pollicis mechanical activity in response to low (0.1 and 2 Hz) and high (50 and 100 Hz) frequency stimulation 15 min after edrophonium 250, 500 and 1000 micrograms kg-1, given to antagonize vecuronium-induced block at 10, 25 and 50% pre-reversal twitch height. We studied 54 ASA class I and II anaesthetized (methohexitone, fentanyl, nitrous oxide) young adult patients allocated randomly to nine groups of six patients each. The greater sensitivity of train-of four (TOF) ratio and residual force after 100-Hz, 5-s tetanic stimulation (RF100) to residual deficit allowed discrimination more readily between the effects of edrophonium dose and pre-reversal twitch height (P < 0.001, two-way analysis of variance). The highest reversal scores (approximately 0.9 TOF ratio and 0.6 RF100) were obtained when edrophonium 500-1000 mg kg-1 was given at 50% twitch height (P < 0.05, Duncan's test).

[Spontaneous development of paralysis induced by equipotent doses of vecuronium, atracurium, fazadinium, pancuronium, gallamine and d-tubocurarine]. / Evolution spontanée de la paralysie obtenue par des doses équipotentes de vécuronium, atracurium, fazadinium, pancuronium, gallamine et d-tubocurarine.

Thirty-six patients undergoing elective surgery were studied after obtaining their informed consent. They were randomly assigned to six series of six patients each. One hour before anaesthesia, all patients received 0.2 mg.kg-1 diazepam orally. After induction of anaesthesia with 1-1.5 mg.kg-1 methohexitone and 5 micrograms.kg-1 fentanyl, the patients were paralysed and ventilation was controlled manually (semi-open circuit; 50% N2O/50% O2). Each patient received a single dose of either 70 micrograms.kg-1 fazadinium, 70 micrograms.kg-1 pancuronium, 2,500 micrograms.kg-1 gallamine or 450 micrograms.kg-1 d-tubocurarine. Neuromuscular function was monitored by measuring the isometric contraction of the adductor pollicis muscle in response to supramaximal stimulations of the ulnar nerve at the wrist (square wave pulse of 0.2 ms duration at supramaximal intensity delivery at 0.1 Hz). Three parameters were measured: the time between the injection of the relaxant drug and recovery of the twitch height at 50% of its baseline (RT0-50); the time between the injection of the relaxant drug and recovery of the twitch height at 90% of its baseline (RT0-90); the time between the injection of the relaxant drug and recovery of the twitch height from 25 to 75% of its baseline (RT25-75). The values of the observed parameters were expressed in minutes (means +/- SEM).(ABSTRACT TRUNCATED AT 250 WORDS)