Management of spasticity associated pain with botulinum toxin A

Lesions of the central nervous system often result in an upper motor neuron syndrome including spasticity, paresis with pyramidal signs, and painful s pasms. Pharmacological treatment with oral antispasticity drugs is frequent ly associated with systemic side effects which limit their clinical use. Bo tulinium Toxin A (BtxA) injected in spastic muscles has been shown to be ef fective in reducing muscle tone, but only few studies have reported pain re lief as additional benefit. Therefore, we investigated the effects of local BtxA injections in 60 patients with acute (<12 months) and chronic spastic ity and pain in a prospective multicellular study. Target muscles for BtxA were selected on the basis of clinical examination. Intramuscular BtxA inje ctions were placed in muscles exhibiting increased muscle tone in combinati on with pain during passive joint movement. Patients received a mean total dose of 165.7+/-108.2 [30-400] units BOTOX(R) per treatment session in a me an 3.4+/-1.5 muscles. Baseline and follow-up (mean 5.9 weeks) measures incl uded a patient self-assessment of pain and function on a five-level scale, a psychian's evaluation of function, and a global rating of response to Btx A. Fifty-four of sixty patients experienced improvement in pain without sub jective functional improvement. The effects were comparable in acute (n = 1 7) and chronic (n = 43) spasticity. Physician's assessment of gain in funct ion increased significantly (p < 0.05) only in patients with chronic spasti city. No serious adverse event was observed. Mild reversible side effects ( local pain, hematoma, edema, mild weakness) were observed in four patients. In conclusion, we found that intramuscular BtxA injections are a potent, w ell-tolerated treatment modality to significantly reduce spasticity-related local pain. This problem may be a main indication, especially in patients with poor response or intolerable side effects to oral medication.