Toxine botulique et douleur : que faut-il en attendre?

ISBN 978271841246

Structure, pharmacology and immunology of the botulinum neurotoxins : the clinical's point of view

ISBN: 978041538651

[Painful peripheral neuropathy]

International audienc

Neuropathies sensitives à petites fibres. Que peut-on attendre de la toxine botulique dans le traitement de la douleur ?

International audienc

Practical handbook on botulinum toxin

ISBN : 978-2-35327-001-

Botulinum toxin type A induces direct analgesic effects in chronic neuropathic pain.

MMNPInternational audienceOBJECTIVE: Botulinum toxin type A (BTX-A) has been reported to have analgesic effects independent of its action on muscle tone, possibly by acting on neurogenic inflammation. Such a mechanism may be involved in peripheral neuropathic pain. METHODS: A possible direct analgesic effect of BTX-A pain processing was investigated in 29 patients with focal painful neuropathies and mechanical allodynia using a randomized, double-blind, placebo-controlled design. Patients received a one-time intradermal administration of BTX-A (20-190 units) into the painful area. Outcome measures, evaluated at baseline, then at 4, 12, and 24 weeks, included average spontaneous pain intensity, quantified testing of thermal and mechanical perception and pain, allodynia to brushing (area, intensity), neuropathic symptoms, clinical global impression, and quality of life. RESULTS: BTX-A treatment, relative to placebo, was associated with persistent effects on spontaneous pain intensity from 2 weeks after the injection to 14 weeks. These effects correlated with the preservation of thermal sensation at baseline (p < 0.05). BTX also improved allodynia to brush and decreased pain thresholds to cold, without affecting perception thresholds. There were sustained improvements in the proportion of responders (number needed to treat for 50% pain relief: 3.03 at 12 weeks), neuropathic symptoms, and general activity. Most patients reported pain during the injections, but there were no further local or systemic side effects. INTERPRETATION: These results indicate for the first time that BTX-A may induce direct analgesic effects in patients with chronic neuropathic pain independent of its effects on muscle tone and suggest novel indications for BTX-A in analgesia

Continuous nerve blocks in the management of bone pain due to compression by cancer metastasis: place in palliative care units.

International audienc

Dose equivalence of two commercial preparations of botulinum neurotoxin type A: time for a reassessment?

International audienceBACKGROUND: The units of different preparations of botulinum neurotoxin type A (BoNT-A) have different potencies, and dosing recommendations for each product are not interchangeable. Historically, there has been debate concerning the dose-equivalence ratio that should be used in clinical practice. METHODS: Published evidence was considered to establish an appropriate dose-conversion ratio for the two main commercially available preparations of BoNT-A--Dysport (Dp) and Botox (Bx). RESULTS: Four key areas of evidence were identified: nonclinical and preclinical studies; studies exploring the diffusion characteristics and effects of complexing proteins; comparative experimental data from human studies; and clinical studies. Nonclinical data indicate that the principal reasons for differences in unit potency between the two products are dilution artefacts in the mouse assay. Use of saline as a diluent, at high dilutions, results in significant loss of potency in the Bx assay, whereas use of gelatin phosphate buffer in the Dp assay procedure protects the toxin during dilution. The published data on mouse assays show a Dp : Bx unit ratio range of 2.3-2.5 : 1 in saline and 1.8-3.2 : 1 in gelatin phosphate buffer. Data indicate that complexing proteins or size of the complex, which is highly pH sensitive, play no role in toxin diffusion and that Dp and Bx have similar diffusion characteristics when used at comparable doses. Randomized, controlled clinical studies indicate that 3 : 1 is more appropriate than 4 : 1, but the two products are not equivalent at this ratio. Comparative human experimental studies using the extensor digitorum brevis test, facial lines and anhidrotic action halo tests support dose-conversion ratios less than 3 : 1. LIMITATIONS: Data comparing dose equivalence ratios from the non-clinical setting should be extrapolated into the clinical setting with some caution. CONCLUSIONS: Dose-conversion ratios between Dp and Bx of 4 : 1 and greater are not supported by the recent literature

Intraoperative use of the Medtronic O-arm for deep brain stimulation procedures.

International audienceThe purpose of this study was to analyze the feasibility and utility of 3D imaging to help lead positioning during a deep brain stimulation (DBS) procedure. A bilateral subthalamic DBS procedure was conducted in 2 patients for idiopathic Parkinson's disease. Subthalamic nucleus targeting was based on preoperative stereotactic MRI. We used the Medtronic O-arm to perform 2D-imaging control (frontal and lateral) as well as quick (<30 s) 3D acquisition. This allowed us to check the positioning of micro-macro electrodes and definite electrodes. 3D images were fused with postoperative CT to assess their accuracy, and with preoperative MRI to visualize the anatomical location of the electrodes. 3D imaging is a quick and safe method to ensure perioperative control of lead placement during DBS procedures