[Botulinum toxin treatment of hip adductor spasticity in multiple sclerosis].

Spasticity results in a resistance to passive movement and decrease of passive mobility of the involved joints and is defined as a state of hypertonicity with exaggeration of tendon reflexes mediated by a loss of inhibitory control of upper motor neurons. In patients with severe stages of multiple sclerosis (MS) spasticity of the lower limbs often leeds to a spastic pattern with hip adduction resulting in decreased range-of-motion (ROM), increased pain, spasms, and functional disability (disturbed gait and sitting position) as well as difficulties with perineal hygiene. Local botulinum toxin type A (Btx-A) injections in spastic muscles offer a new treatment approach for managing spasticity and associated problems. Up to now Btx-A is approved for the treatment of blepharospasm and cervical dystonia and the treatment of equinous gait in children with cerebral palsy in Austria and Germany. Up to now only in Switzerland Botox is licensed for the treatment of focal spasticity. Btx-A is a neurotoxin derived from Clostridium botulinum. In most european countries Btx-A is available as Dysport (vial = 500 units) and Botox (vial = 100 units). In prospective studies a ratio of 1 unit Botox to 3-4 units Dysport was found. Following intramuscular injection Btx-A blocks the release of acetylcholine at the neuromuscular junctions, thereby inhibiting muscle contraction, and decreases spastic muscle tone and muscle spindles afferent information to the spinal cord. The spectrum of side effects includes local weakening of the injected and adjacent muscles as well as pain and haematoma at the injection site. At therapeutic doses side effects are local and transient. According to a double blind, placebo controlled, dose ranging study published by Hyman et al. (2000, Dysport in a dose of 500, 1000 and 1500 units reduced the degree of hip adductor spasticity associated with MS, and this benefit was evident despite concomitant use of oral antispasticity medication. According to the results of the study there was a clear trend towards greater efficacy and duration of effects with higher doses of Dysport. Taking efficacy and adverse events into account (incidence of muscle weakness was higher for the 1500 units group than for placebo) the optimal dose for hip adductor spasticity seems to be 1000 units Dysport divided between the adductor magnus, longus and brevis muscles and between both legs. To increase Btx-A effects following injection of hip adductors additional physiotherapy and casting or orthosis to increase passive hip-abduction is recommended. According to the literature anatomical localisation of the adductor muscles for injection and aspiration following insertion of the needle, to avoid injection of the toxin into a vessel, should be performed. A maximum dose of 1500 units Dysport (400 units Botox) per treatment session and 250 units Dysport (50 units Botox) per injection site is recommended. See table for dose-range of Dysport, and Botox in the treatment of adult patients with hip-adductor spasticity. For evaluation of treatment effects in hip adductor spasticity clinical examination with specific scales and measurements (see Appendix) at baseline, 4 and 12 weeks following BtxA injection is recommended:--Global rating of severity (0-4; patient's self assessment and physician's rating) --Global rating of response (-4 - +4; patient's self assessment and physician's rating)--Visual Analogue Scale (patient's self assessment of pain)--Active and passive ROM (manual goniometer)--Distance between the medial femur condyles in thigh extension (distance in cm)--Modified Ashworth scale (0-4)--Ten meter walking time (seconds)--Functional Ambulation Categories (0-5)--Score of perineal hygiene (0-5).