Botulinum toxin (BoNT) has been widely employed to treat poststroke spasticity,
cervical dystonia and muscle hyperactivity. Recently, BoNT
injections are increasingly used in treating
musculoskeletal pain. The mechanism of BoNT in
pain relief comprises relaxation of overused muscles and inhibition of inflammatory nociceptive
cytokines/
neurotransmitters. As BoNT
injections seem promising in treating painful musculoskeletal disorders, we aimed to investigate its effectiveness in shoulder and upper limb
pain. Although the present article is a narrative review, we employed a systematic approach to search for relevant articles in PubMed. A total of 19 clinical studies were included. Here, we observed that intramuscular BoNT
injections were helpful in
stroke patients with hemiplegic
shoulder pain. In shoulder joint
pain, intra-articular and intrabursal BoNT
injections achieved a longer period of
pain relief than
corticosteroid injections. Similarly, a more durable effect of intramuscular BoNT than saline
injections was seen in shoulder myofascial
pain. Its use in
complex regional pain syndrome and persistent upper limb
pain in
breast cancer survivors was insufficient, necessitating more studies. Since not all of the included studies could provide Class I of evidence based on the efficacy criteria used by American Academy of Neurology, controlled clinical trials in a larger number of patients are necessary to verify validity of these findings in the future.