Botulinum toxin type A injections for myofascial pain syndrome and tension-type headache

WITHDRAWN: Botulinum toxin for subacute/chronic neck pain

Withdrawn due to non‐compliance with The Cochrane Collaboration’s Commercial Sponsorship Policy

The editorial group responsible for this previously published document have withdrawn it from publication.

WITHDRAWN: Medicinal and injection therapies for mechanical neck disorders

Withdrawn due to non‐compliance with The Cochrane Collaboration’s Commercial Sponsorship Policy

The editorial group responsible for this previously published document have withdrawn it from publication.

Botulinum toxin for myofascial pain syndromes in adults

BACKGROUND

This is an updated version of the original Cochrane review published in Issue 4, 2012. Myofascial pain syndrome (MPS) is a regional muscular pain syndrome characterised by the presence of trigger points, which are painful points in one or more muscles. The pain can be felt at the site where the trigger point is located or it can be felt away from that place when the muscle is pressed (referred pain). Botulinum toxin is a protein produced by the bacterium Clostridium botulinum and is a potent neurotoxin that eventually inhibits muscle contractions. It is capable of selectively weakening painful muscles and interrupting the pain cycle.

OBJECTIVES

To assess the effectiveness and safety of botulinum toxin A (BTXA) in the treatment of myofascial pain syndrome (MPS), excluding MPS in neck and head muscles.

SEARCH METHODS

This is an updated version of the original Cochrane review published in Issue 4, 2012. The search strategy for the update was the same as in the original review and we searched CENTRAL in The Cochrane Library (2013, Issue 11 of 12), MEDLINE (Ovid) (2012 to 29 November 2013) and EMBASE (Ovid) (2012 to 27 November 2013). The search strategy was composed of terms for myofascial pain and botulinum toxin. For the original review, we also searched the Cochrane Pain, Palliative and Supportive Care (PaPaS) Review Group Specialised Register until December 2011, PubMed (from 1966 to 2011) and LILACS (from 1982 to 2011). There was no language restriction.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving botulinum toxin for treating participants with MPS. We excluded studies with MPS of the neck and head from this review as they have already been assessed in existing systematic reviews. We considered a diagnosis of MPS to be based on the identification of trigger points in the taut band through palpation of sensitive nodules, local twitch response and specific patterns of referred pain associated with each trigger point.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened identified studies, extracted data, assessed trial quality and analysed results using the Cochrane PaPaS Review Group criteria.

MAIN RESULTS

Four studies with a total of 233 participants, comparing BTXA with placebo, met the inclusion criteria. In one study with 145 participants, significant improvement rates of pain intensity scores and duration of daily pain were demonstrated when comparing BTXA with placebo. The three other studies showed that there was no statistically significant difference between BTXA and placebo in pain intensity.

AUTHORS' CONCLUSIONS

Since the first publication of this review, no new studies were found. There is inconclusive evidence to support the use of botulinum toxin in the treatment of MPS based on data from four studies with a total of 233 participants, which we considered were of sufficient quality to be included in this review. Meta-analyses were not possible due to the heterogeneity between studies. We suggest that in future studies the same methodology to assess pain, a standardised dose of treatment, follow-up of at least four months (to observe the maximum and minimum curve of the drug effect) and appropriate data presentation should be used. More high-quality RCTs of botulinum toxin for treating MPS need to be conducted before firm conclusions on its effectiveness and safety can be drawn.

A prospective randomized double-blinded pilot study to examine the effect of botulinum toxin type A injection versus Lidocaine/Depomedrol injection on residual and phantom limb pain: initial report

OBJECTIVE

Botulinum toxin type A (Botox) injection has been used to manage pain. However, it remains to be proved whether Botox injection is effective to relieve residual limb pain (RLP) and phantom limb pain (PLP).

DESIGN

Randomized, double-blinded pilot study.

SETTING

Medical College and an outpatient clinic in Department of Physical Medicine and Rehabilitation.

PARTICIPANTS

Amputees (n=14) with intractable RLP and/or PLP who failed in the conventional treatments.

INTERVENTIONS

Study amputees were randomized to receive 1 Botox injection versus the combination of Lidocaine and Depomedrol injection. Each patient was evaluated at baseline and every month after the injection for 6 months.

MAIN OUTCOME MEASURE

The changes of RLP and PLP as recorded by VAS, and the changes of the pressure pain tolerance as determined by a pressure algometer.

RESULTS

All patients completed the protocol treatment without acute side effects, and monthly assessments of RLP, PLP, and pain tolerance after the treatment. The time trend in the outcomes was modeled as an immediate change owing to the treatment followed by a linear tread afterward. Repeated measures were incorporated using mixed effects modeling. We found that both Botox and Lidocaine/Depomedrol injections resulted in immediate improvements of RLP (Botox: P=0.002; Lidocaine/Depomedrol: P=0.06) and pain tolerance (Botox: P=0.01; Lidocaine/Depomedrol: P=0.07). The treatment effect lasted for 6 months in both groups. The patients who received Botox injection had higher starting pain than those who received Lidocaine/Depomedrol injection (P=0.07). However, there were no statistical differences in RLP and pain tolerance between these 2 groups. In addition, no improvement of PLP was observed after Botox or Lidocaine/Depomedrol injection.

CONCLUSIONS

Both Botox and Lidocaine/Depomedrol injections resulted in immediate improvement of RLP (not PLP) and pain tolerance, which lasted for 6 months in amputees who failed in conventional treatments.

Botulinum toxin for myofascial pain syndromes in adults

BACKGROUND

Myofascial pain syndrome (MPS) is a regional muscular pain syndrome characterised by the presence of trigger points, which are painful points in one or more muscles. The pain can be felt at the site where the trigger point is located or it can be felt away from that place when the muscle is pressed (referred pain). Botulinum toxin is a protein produced by the bacterium Clostridium botulinum and is a potent neurotoxin that eventually inhibits muscle contractions. It is capable of selectively weakening painful muscles and interrupting the pain cycle.

OBJECTIVES

To assess the effectiveness and safety of botulinum toxin in treating MPS, excluding MPS in neck and head muscles.

SEARCH METHODS

The search strategy was composed of terms for myofascial pain and botulinum toxin. We searched the Cochrane Pain, Palliative and Supportive Care (PaPaS) Review Group's Specialised Register until December 2011, CENTRAL (Cochrane Database of Systematic Reviews 2011, Issue 4), PUBMED (from 1966 to 2011), EMBASE (from 1980 to 2011) and LILACS (from 1982 to 2011). There was no language restriction.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) involving botulinum toxin for treating participants with MPS. We excluded studies with MPS of the neck and head from this review, as they have already been assessed in existing systematic reviews. We considered a diagnosis of MPS to be based on the identification of trigger points in the taut band through palpation of sensitive nodules, local twitch response and specific patterns of referred pain associated with each trigger point.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened identified studies, extracted data, assessed trial quality and analysed results using the Cochrane PaPaS Review Group criteria.

MAIN RESULTS

Four studies with a total of 233 participants, comparing botulinum toxin A (BTXA) with placebo, met the inclusion criteria. In one study with 145 participants, a significant improvement rate of pain intensity scores, as shown by the mean difference (MD) of -0.23 (95% confidence interval (CI) -0.26 to -0.20; P value < 0.00001) and duration of daily pain (MD -1.11; 95% CI -1.37 to -0.85; P value < 0.00001), was demonstrated when comparing BTXA with placebo. The three other studies showed that there was no statistically significant difference between BTXA and placebo in pain intensity.

AUTHORS' CONCLUSIONS

There is inconclusive evidence to support the use of botulinum toxin in the treatment of MPS based on data from four studies with a total of 233 participants, which we considered adequate to be included in this review. Meta-analyses were not possible due to the heterogeneity between studies. We suggest that in future studies the same methodology to assess pain, a standardised dose of treatment, follow-up of at least four months (to observe the maximum/minimum curve of the drug effect) and appropriate data presentation should be used. More high-quality RCTs of botulinum toxin for treating MPS need to be conducted before firm conclusions on its effectiveness and safety can be drawn.

Botulinum toxin for subacute/chronic neck pain

BACKGROUND

Neck disorders are common, disabling and costly. Botulinum toxin (BoNT) intramuscular injections are often used with the intention of treating neck pain.

OBJECTIVES

To systematically evaluate the literature on the treatment effectiveness of BoNT for neck pain, disability, global perceived effect and quality of life in adults with neck pain with or without associated cervicogenic headache, but excluding cervical radiculopathy and whiplash associated disorder.

SEARCH STRATEGY

We searched CENTRAL, MEDLINE, AMED, Index to Chiropractic Literature, CINAHL, LILACS, and EMBASE from their origin to 20 September 2010.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials in which BoNT injections were used to treat subacute or chronic neck pain.

DATA COLLECTION AND ANALYSIS

A minimum of two review authors independently selected articles, abstracted data, and assessed risk of bias, using the Cochrane Back Review Group criteria. In the absence of clinical heterogeneity, we calculated standardized mean differences (SMD) and relative risks, and performed meta-analyses using a random-effects model. The quality of the evidence and the strength of recommendations were assigned an overall grade for each outcome.

MAIN RESULTS

We included nine trials (503 participants). Only BoNT type A (BoNT-A) was used in these studies.High quality evidence suggests there was little or no difference in pain between BoNT-A and saline injections at four weeks (five trials; 252 participants; SMD pooled -0.07 (95% confidence intervals (CI) -0.36 to 0.21)) and six months for chronic neck pain. Very low quality evidence indicated little or no difference in pain between BoNT-A combined with physiotherapeutic exercise and analgesics and saline injection with physiotherapeutic exercise and analgesics for patients with chronic neck pain at four weeks (two trials; 95 participants; SMD pooled 0.09 (95% CI -0.55 to 0.73)) and six months (one trial; 24 participants; SMD -0.56 (95% CI -1.39 to 0.27)). Very low quality evidence from one trial (32 participants) showed little or no difference between BoNT-A and placebo at four weeks (SMD 0.16 (95% CI -0.53 to 0.86)) and six months (SMD 0.00 (95% CI -0.69 to 0.69)) for chronic cervicogenic headache. Very low quality evidence from one trial (31 participants), showed a difference in global perceived effect favouring BoNT-A in chronic neck pain at four weeks (SMD -1.12 (95% CI: -1.89 to -0.36)).

AUTHORS' CONCLUSIONS

Current evidence fails to confirm either a clinically important or a statistically significant benefit of BoNT-A injection for chronic neck pain associated with or without associated cervicogenic headache. Likewise, there was no benefit seen for disability and quality of life at four week and six months.

The efficacy of botulinum toxin type A in managing chronic musculoskeletal pain: a systematic review and meta analysis

BACKGROUND

Botulinum toxin type A (BoNTA) is a neurotoxin that acts by inhibiting the release of neurotransmitters acetylcholine at neuromuscular junctions, thus reducing muscular contractions. Recent evidence suggests that BoNTA can reduce nociceptive activities of sensory neurons in animal models by inhibiting release of certain neuropeptides. Despite the therapeutic benefit of BoNTA in alleviating painful muscle spasms, its efficacy in other musculoskeletal pain conditions is less clear.

OBJECTIVE

We aim to examine the efficacy of BoNTA in reducing chronic musculoskeletal pain.

METHODS

Studies for inclusion in our report were identified using MEDLINE, EMBASE, PUBMED, Cochrane Central Register of Controlled Trials, CINAHL, and reference lists of relevant articles. Studies were considered eligible for inclusion if they were randomized controlled trials (RCTs), evaluating the efficacy of BoNTA injections in pain reduction. All studies were assessed and data were abstracted independently by paired reviewers. The outcome measures were baseline and final pain scores as assessed by the patients. The internal validity of trials was assessed with the Jadad scale. Disagreements were resolved through discussions.

MAIN RESULTS

Twenty-one studies were included in the systematic review and 15 of them were included in the final meta-analysis. There was a total of 706 patients in the meta-analysis, represented from trials of plantar fasciitis (n = 1), tennis elbow (n = 2), shoulder pain (n = 1), whiplash (n = 3), and myofascial pain (n = 8). Overall, there was a small to moderate pain reduction among BoNTA patients when compared to control (SMD = -0.27, 95% CI: -0.44 to -0.11). When the results were analyzed in subgroups, only tennis elbow (SMD = -0.44, 95% CI: -0.86 to -0.01) and plantar fasciitis (SMD = -1.04, 95% CI: -1.68 to -0.40) demonstrated significant pain relief. Although not in the meta-analysis, one back pain study also demonstrated positive results for BoNTA. Lastly, BoNTA was effective when used at ≥ 25 units per anatomical site or after a period ≥ 5 weeks.

CONCLUSION

In our meta-analysis, BoNTA had a small to moderate analgesic effect in chronic musculoskeletal pain conditions. It was particularly effective in plantar fasciitis, tennis elbow, and back pain, but not in whiplash or shoulder pain patients. However, more evidence is required before definitive conclusions can be drawn. On the other hand, there is convincing evidence that BoNTA lacks strong analgesic effects in patients with myofascial pain syndrome. A general dose-dependent and temporal response with BoNTA injections was also observed.

[Systematic review: can botulinum toxin be recommended as treatment for pain in myofascial syndrome?]

Myofascial pain syndrome (MPS) may have an intrinsic muscle spasm component.

AIM

Since botulinum toxin has been successfully used to reduce hypertonicity in several neurological disorders, we analyzed the efficacy of botulinum toxin A or B in reducing pain in MPS.

METHODS

We performed a systematic review through an electronic search in MEDLINE, EMBASE, and Cochrane Library Plus. All clinical trials of botulinum toxin and regional pain were selected. In addition, the abstracts of the ACR and EULAR meetings in the previous 3 years were searched manually. The studies identified were reviewed and analyzed by 2 independent reviewers.

RESULTS

Eight studies met the inclusion criteria. The methodological quality was generally low. Botulinum toxin was compared to saline solution (6 studies), to steroids (2 studies), and to lidocaine and dry needle (1 study arm). The population studied included persons with neck pain (n=3), low back pain (n=2), piriformis syndrome (n=2), several trigger points (n=1), and healthy volunteers in whom pain was provoked (n=1). Botulinum toxin showed a certain advantage over saline solution and steroids in pain control. A meta-analysis of the 3 studies with efficacy measures that could be combined showed a weighted mean difference in pain on a 0-10 visual analogue scale of -2.72 (95% CI: -3.86; -1.58). However, botulinum toxin showed no advantage over lidocaine (p>0.016).

CONCLUSIONS

Currently, there is insufficient evidence to confirm the real efficacy of botulinum toxin A and B in the treatment of MPS. Given the high cost of botulinum toxin, long-term high quality studies are required.

Medicinal and injection therapies for mechanical neck disorders

BACKGROUND

Controversy persists regarding medicinal therapies and injections.

OBJECTIVES

To determine the effects of medication and injections on primary outcomes (e.g. pain) for adults with mechanical neck disorders and whiplash.

SEARCH STRATEGY

We searched CENTRAL, MANTIS, CINAHL from their start to May 2006; MEDLINE and EMBASE to December 2006. We scrutinised reference lists for other trials.

SELECTION CRITERIA

We included randomised controlled trials with adults with neck disorders, with or without associated headache or radicular findings. We considered medicinal and injection therapies, regardless of route of administration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected articles, abstracted data and assessed methodological quality. When clinical heterogeneity was absent, we combined studies using random-effects models.

MAIN RESULTS

We found 36 trials that examined the effects of oral NSAIDs, psychotropic agents, steroid injections, and anaesthetic agents. Trials had a mean of 3.1 on the Jadad Scale for methodological quality; 70% were high quality. For acute whiplash, administering intravenous methylprednisolone within eight hours of injury reduced pain at one week (SMD -0.90, 95% CI -1.57 to -0.24), and sick leave but not pain at six months compared to placebo in one trial. For chronic neck disorders at short-term follow-up, intramuscular injection of lidocaine was superior to placebo (SMD -1.36, 95% CI -1.93 to -0.80); NNT 3, treatment advantage 45% and dry needling, but similar to ultrasound in one trial each. In chronic neck disorders with radicular findings, epidural methylprednisolone and lidocaine reduced neck pain and improved function more than when given by intramuscular route at one-year follow-up, in one trial. In subacute and chronic neck disorders, muscle relaxants, analgesics and NSAIDs had limited evidence and unclear benefits. In participants with chronic neck disorders with or without radicular findings or headache, there was moderate evidence from five high quality trials that Botulinum toxin A intramuscular injections had similar effects to saline in improving pain (pooled SMD: -0.39, 95%CI -1.25 to 0.47), disability or global perceived effect.

AUTHORS' CONCLUSIONS

The major limitations are the lack of replication of the findings and sufficiently large trials. There is moderate evidence for the benefit of intravenous methylprednisolone given within eight hours of acute whiplash, from a single trial. Lidocaine injection into myofascial trigger points appears effective in two trials. There is moderate evidence that Botulinum toxin A is not superior to saline injection for chronic MND. Muscle relaxants, analgesics and NSAIDs had limited evidence and unclear benefits.

Low-Dose Botulinum Toxin Type A for the Treatment of Refractory Piriformis Syndrome

STUDY OBJECTIVES

To evaluate the efficacy of a single, low-dose injection of botulinum toxin type A in relieving pain in Korean patients with piriformis syndrome resistant to conventional therapy, and to assess the drug's influence on these patients' quality of life.

DESIGN

Prospective, single-site, open-label trial.

SETTING

Rehabilitation medicine clinic in Seoul, Korea.

PATIENTS

Twenty-nine patients with a confirmed diagnosis of chronic piriformis syndrome and 82 age- and sex-matched healthy subjects were enrolled from April 1, 2003-February 28, 2004. Intervention. In 20 of the patients, botulinum toxin type A 150 U was injected using computed tomographic guidance into the affected unilateral piriformis muscle. The other nine patients served as active controls and received an injection of dexamethasone 5 mg and 1% lidocaine. The healthy subjects did not receive any injection.

MEASUREMENTS AND MAIN RESULTS

The patients' pain at baseline and at 4, 8, and 12 weeks after treatment was rated by using a numeric rating scale. Health-related quality of life was assessed by using the validated Korean version of the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36) at baseline and at 4 weeks of treatment. Healthy subjects also completed the SF-36 at baseline. Pain intensity scores were significantly lower at 4, 8, and 12 weeks after treatment than at baseline (p<0.0001). Baseline scores from the SF-36 subscales, including those for physical functioning (p<0.0001), role physical (p<0.0001), bodily pain (p<0.0001), general health (p<0.0001), vitality (p<0.0001), and social functioning (p<0.002), were significantly lower in the patients than in the healthy subjects. Four weeks after treatment, physical functioning (p=0.003), role physical (p=0.021), bodily pain (p=0.016), general health (p=0.013), vitality (p=0.031) and social functioning (p=0.035) improved significantly from baseline in the patients. However, at 4 weeks, patients in the active control group were withdrawn from the study because their pain did not improve, and continuation without further medical care was considered unethical.

CONCLUSION

A low dose of botulinum toxin type A relieved pain and improved quality of life in patients with refractory piriformis syndrome.

Botulinum toxin type A in prophylactic treatment of migraine

Current migraine preventive therapies are often unsatisfactory because of their limited efficacy, adverse effects, and drug interactions. An open-label, non-controlled study of botulinum toxin type A (BTX-A) suggested some benefits for patients with migraine. To assess the efficacy and safety of BTX-A, a randomized, double-blind, vehicle-controlled, parallel group study was conducted in 32 patients with a history of 2 to 8 migraine attacks per month, with or without aura. The patients were randomized to receive single administrations of 50-U BTX-A or vehicle injected into multiple sites of pericranial muscles at the same visit. Patients kept daily diaries in which they recorded outcome measures like migraine frequency, migraine severity, and the occurrence of migraine-associated symptoms. Patients graded symptoms on a 4-point scale ranging from grades 0 to 3 before and up to 3-months after treatment. The assessments were made at 0, 1, and 3 months. The primary efficacy parameters included number of headaches resolved (grade 3/2 to grade 0) and alleviation of other accompanying symptoms of migraine. The supplementary end point included improvement in quality of life (QOL). About 75% of patients reported complete relief to mild headache (grade 0-1) by BTX-A and none by placebo group. Patient' QOL parameters like energy/vitality and feelings and concerns about the treatment had shown considerable improvement. However, normal day-to-day work functioning and social interactions deteriorated. No adverse effects were reported in any of the patients in either of the groups during the study. It is evident from the study that pericranial injection of 50-U BTX-A showed good efficacy and tolerability as a prophylactic agent. However, this therapy will be expensive to the patients, but it is far superior in providing relief to the patients compared with existing therapies.

Medicinal and injection therapies for mechanical neck disorders

BACKGROUND

Medicinal therapies and injections are commonly recommended for neck pain, yet controversy persists over their effectiveness.

OBJECTIVES

To determine the effect of medicines and injections on pain, function/disability, patient satisfaction and range of motion in participants with mechanical neck disorders (MND).

SEARCH STRATEGY

We searched CENTRAL (Issue 4, 2002), and MEDLINE, EMBASE, MANTIS, CINHAL from their start to March 2003. We scrutinized reference lists for other trials.

SELECTION CRITERIA

We included randomized controlled trials with adults with MND, with or without associated headache or radicular findings. We considered medicinal and injection therapies, regardless of route of administration.

DATA COLLECTION AND ANALYSIS

Two authors independently selected articles, abstracted data and assessed methodological quality using the Jadad criteria. Consensus was used to resolve disagreements. When clinical heterogeneity was absent, we combined studies using random-effects meta-analysis models.

MAIN RESULTS

We found 32 trials that examined the effects of oral NSAIDs, psychotropic agents, injections of steroids, and anaesthetic agents. Overall, methodological quality had a mean of 3.2/5 on the Jadad Scale. For acute whiplash, administering intravenous methylprednisolone within eight hours reduced pain at one week, and sick leave but not pain at six months compared to placebo. For chronic MND at short-term follow-up, intramuscular injection of lidocaine was superior to placebo or dry needling, but similar to ultrasound. In chronic MND with radicular findings, epidural methylprednisolone and lidocaine reduced neck pain and improved function at one-year follow-up compared to the intramuscular route. In subacute/chronic MND, we found conflicting evidence of pain reduction for oral psychotropic agents compared to placebo or control. Single trials of eperison hydrochloride and tetrazepam showed positive results. Results for cyclobenzaprine were mixed. Diazepam did not show benefit. Other treatments including NSAIDS and nerve blocks had unclear or limited evidence of benefit. In participants with chronic MND with or without radicular findings or headache, there was moderate evidence from five high quality trials showing that Botox A intramuscular injections were not better than saline in improving pain (pooled SMD: -0.39 (95%CI: -1.25 to 0.47), disability or global perceived effect.

AUTHORS' CONCLUSIONS

Intra-muscular injection of lidocaine for chronic MND and intravenous injection of methylprednisolone for acute whiplash were effective treatments. There was limited evidence of effectiveness of epidural injection of methylprednisolone and lidocaine for chronic MND with radicular findings. Oral psychotropic agents had mixed results. There was moderate evidence that Botox A intramuscular injections for chronic MND were no better than saline. Other medications, including NSAIDs, had contradictory or limited evidence of effectiveness.

Injections of botulinum toxin type a produce pain alleviation in intractable trigeminal neuralgia

To report the effects of local injections of botulinum toxin type A regarding pain relief and long-term control in a patient with intractable trigeminal neuralgia. The patient was a 75-year-old man with trigeminal neuralgia in the left hemifacial region. His pain was unbearable and could not be controlled by carbamazepine, amitriptyline, or blocked by infiltration of a glycerol solution or phenol. The authors evaluated pain intensity, quality, and location using a Visual Analog Scale to establish the efficacy of botulinum toxin type A injections. Two units of botulinum toxin type A (Botox) were subcutaneously injected once in eight points distributed along the territory of V1 and V2. Visual Analog Scores were measured at baseline and at 7, 30, 60, and 90 days after treatment. The authors also examined the patient's general condition and daily life activities. The Visual Analog values were, respectively, 82, 54, 25, 25, and 45 mm at each follow-up examination. No side effects were observed on the site of injection and on the patient's clinical state. The authors have been able to reduce trigeminal neuralgia pain with botulinum toxin type A injections in the V1, V2 territory during all the period of study, as well as to withdraw all medication. Interestingly, there was concomitant reduction of pain also in V3, which was not injected.

Effects of Botulinum Toxin Type B on Stump Pain and Involuntary Movements of the Stump

Patients who had previously undergone amputation of the arm (n = 2) or leg (n = 2) were treated with botulinum toxin type B injections at several trigger points of their stump musculature. We administered a total dose of 2500 IU of botulinum toxin type B (Neurobloc, Elan Pharma, Munich, Germany) to the arm amputation stumps, 5000 IU for one amputation of the lower leg, and 2500 IU to the other lower leg amputation of a patient with a very low baseline body weight. Two patients reported that the injection was very painful. All patients experienced a reduction in stump pain, which lasted for many weeks. Other reports included a reduction in the frequency of pain attacks, cessation of "balloon feelings," improvement in stump allodynia, and decreased occurrence of involuntary stump movements. In addition, quality of sleep at night significantly improved in one patient. Botulinum toxin type B can therefore be regarded as a new treatment option for possible improvements in the rehabilitation of amputees.

Use of botulinum toxin in the treatment of chronic myofascial pain

BACKGROUND

Myofascial pain syndrome (MPS) is defined as acute or chronic pain with sensory or motor autonomic symptoms, referred from active myofascial triggering points with associated dysfunction. Previous studies have suggested the usefulness of botulinum toxin A (BTX-A) in the treatment of MPS since it is capable of controlling muscular spasms, as well as other alternative mechanisms of action.

OBJECTIVES

To analyze the efficacy of BTX-A treatment and its effect on daily life activities assessing pain reduction using a visual analogue scale (VAS); degree of improvement in physical impairment and disability scoring in the Oswestry low back pain questionnaire; and psychologic status using the Hospital Anxiety and Depression Scale (HAD), in patients suffering from MPS.

METHOD

An open-label interventional prospective trial was conducted in 77 patients diagnosed of refractory MPS (defined as the presence of muscle spasm with pain on mobilization or stretching, plus the existence of trigger points with associated referred pain), resistant to both conservative management and to physical therapy. The BTX-A dosages for the different muscles were chosen according to a standardized protocol. Electromyographic guidance was used to localize the motor end plate prior to injection in superficial muscles; while fluoroscopic guidance was employed to evidence intramyofascial spread of the contrast solution within deep muscles. The assessment of treatment efficacy was based on a pain VAS applied before enrollment, at 15, 30, and 90 days and upon completion of the study; the Lattinen test to establish a relationship between pain intensity and its corresponding impact on daily living; and the HAD scale to assess psychologic stress, performed both before treatment and at the end of the study; and the Oswestry Questionnaire was used to evaluate patients' ability to carry out daily life activities according to their degree of physical impairment and disability scores.

RESULTS

The global analysis revealed a positive correlation between the VAS score prior to treatment and the scoring at 15, 30, and 90 days. This correlation was maintained when analyzing independently for superficial or deep muscles. The correlation coefficients for HAD scores and the Lattinen test values showed a significant association between pre- and post-treatment findings. No adverse events were recorded for 83.1% of the cases.

CONCLUSIONS

The results of this study are consistent with other studies showing the efficacy of BTX-A for treating pain in MPS. The evaluation of the psychologic dimension of this disorder and its associated disability can provide valuable information for the adequate management of these patients and for assessing treatment outcome.

Review of the FDA-approved uses of botulinum toxins, including data suggesting efficacy in pain reduction

Botulinum toxin has dramatically improved the treatment of a variety of neurologic disorders. Two botulinum toxin preparations are commercially available in the United States: type A (Botox) and type B (Myobloc). Current indications approved by the United States Food and Drug Administration include cervical dystonia, strabismus, blepharospasm, hemifacial spasm, and glabellar wrinkles for Botox, and cervical dystonia for Myobloc. Botulinum toxin inhibits release of acetylcholine from the neuromuscular junction, resulting in a localized paralysis when minute doses are injected. This mechanism enables botulinum toxin to alleviate symptoms of focal dystonias (which are characterized by excessive muscle contraction), and it may also, along with other theoretical mechanisms, be responsible for pain relief. Studies conducted in patients with cervical dystonia have shown that botulinum toxin effectively reduces pain associated with this disorder, suggesting that this agent may be effective in alleviating other painful syndromes.

Effect of botulinum toxin on endplate noise in myofascial trigger spots of rabbit skeletal muscle

OBJECTIVE

To assess the effect of botulinum toxin type A (BTX-A) on the endplate noise prevalence in rabbit myofascial trigger spots to confirm the role of excessive acetylcholine release on the pathogenesis of myofascial trigger points and to develop an objective indicator of the effectiveness of BTX-A in the treatment of myofascial trigger points.

DESIGN

Eighteen adult New Zealand rabbits were divided into three groups that received a single bolus of BTX-A over a myofascial trigger spot region on one side of the biceps femoris muscle. Another 10 rabbits received multiple-point injections in a myofascial trigger spot where endplate noises were found. A control study was performed on the other side of the biceps femoris muscle. The endplate noise prevalence in a myofascial trigger spot region was assessed.

RESULTS

It was found that injection of BTX-A reduced the prevalence of endplate noise. No significant differences between a single bolus injection and multiple-point injections were noted, although there was some evidence that multiple-point injections might maintain the endplate noise decreasing effect much longer than a single injection.

CONCLUSIONS

This study demonstrated the suppressive effect of BTX-A on endplate noise prevalence in a myofascial trigger spot region. The prevalence of endplate noise in the myofascial trigger point region may be a useful objective indicator for evaluating the therapeutic effectiveness of BTX-A injection to treat myofascial trigger points.