I am on my musculoskeletal placement and have had regular questions in regards to advances in Botulinium Injection into trigger points to relieve myofascial pain. I thought this was an interesting topic to share as the results are very relevant to us as physios. Firstly I’ll explain myofascial pain. It’s a regional skeletal muscular condition presenting with stiffness and pain, characterised by the presence of trigger points in affected muscle areas. Trigger points are focal, palpable, hypersensitive bands of tight muscle. On palpation, trigger points can produce muscle twitch and referred pain.
Despite many postulated mechanisms, the pathology of MPS still remains elusive and appears to involve a complex interaction of numerous pathogenic mechanisms including abnormal motor end plate activity together with peripheral or central sensitisation.
Botulinum Toxin A is a potent neurotoxin produced by a bacterium which acts by blocking Ach release at the neuromuscular junction. BTX has been under investigation since 1968 and has been widely used for the treatment of focal muscle overactivity for greater than 15 years.
A number of small clinical trials have shown some beneficial effect with BTX treatment in patients with myofascial pain syndrome. For example in a small double-blind placebo controlled study of six patients, TP injections of BTX significantly reduced pain by 30% in four of the patients. In another small study involving 33 patients, significantly more patients were asymptomatic after just one injection of BTX in the cervicothoracic muscles when compared to those injected with saline. In a third study involving 40 patients, pain reduction after just two months was significantly more pronounced with a single injection of BTX.
In clinical studies however, results are mixed. When BTX is compared to a control group, limited or no BTX benefits have been found. A study by Ferranke (2005) did not find that injection of BTX directly into TPs to improve pain relief in patients with MPS. They did not find any significant difference between the placebo and BTX groups with respect to pain threshold or use of medications. Another study by Ojala (2005) similarly compared small injectate volumes of saline with injectate of BTX. They did not show any difference in pain scores at the TP between the two groups.
So why is this all important to us as Physios you ask?
Research has hypothesised that other therapies combined with BTX are essential to achieve reduction of myofascial pain (Taimela et al, 2000). A study by Porta (2000) stressed the importance of combining BTX injections with physiotherapy and pharmacological agents. Another study by Wheeler et al (2001) also suggested that physiotherapy is a necessary programmatic element before injection sessions and suggest that it may be a requisite for long term pain relief. They explain that as chronic pain implies, the presence of postural and other factors that predispose the patient to pain conditions will persist beyond normal tissue healing periods if not addressed and treated. Hence physiotherapy plays a key role in maintaining long term relief following any form of surgical intervention.
So here are some suggestions how we can help anyone with painful trigger points before they opt for the more invasive trigger point injections: massage, pulsed ultrasound, dry needling and stretching techniques that invoke reciprocal inhibition. Use of elbows, feet or various tools to direct pressure directly upon the trigger point often occurs, to save practitioner's hands.
A successful treatment protocol relies on identifying trigger points, resolving them and, if all trigger points have been deactivated, elongating the structures affected along their natural range of motion and length. In the case of muscles, which is where most treatment occurs, this involves stretching the muscle using combinations of passive, active, muscle energy techniques and PNF stretching to be effective.
So on a final note, its all great for your patients to want a quick fix to their pain but unless the underlying cause of their pain is dealt with, the trigger points are more than likely going to re-occur.
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