Botulinum toxin for the treatment of musculoskeletal pain and spasm

Evaluation of spasticity: IFCN Handbook Chapter

There is no generally accepted definition of spasticity, but hyperexcitable stretch reflexes, exaggerated tendon jerks, clonus, spasms, cramps, increased resistance to passive joint movement, sustained involuntary muscle activity and aberrant muscle activation, including co-contraction of antagonist muscles are all signs and symptoms which are usually associated clinically to the term spasticity. This review describes how biomechanical and electrophysiological techniques may be used to provide quantitative and objective measures of each of these signs and symptoms. The review further describes how neurophysiological techniques may be used to evaluate pathophysiological changes in spinal motor control mechanisms. It is emphasized that understanding the pathophysiology and distinguishing the specific signs and symptoms associated with spasticity, using objective, valid, and reproducible measurements, is essential for providing optimal therapy.

Evaluation and Management of Neurogenic Thoracic Outlet Syndrome with an Overview of Surgical Approaches: A Comprehensive Review

Neurogenic thoracic outlet syndrome (NTOS) represents a disorder believed to involve compression of one or more neurovascular elements as they exit the thoracic outlet. This comprehensive literature review will focus on the occurrence, classification, etiology, clinical presentation, diagnostic measures, and both nonoperative and operative therapies for NTOS. NTOS represents the most common subtype of thoracic outlet syndrome and can significantly impair quality of life. Botulinum toxin injection into the anterior scalene muscle, or even the middle scalene or pectoralis minor muscles, can reduce the symptoms of this syndrome. The best available evidence for botulinum toxin therapy to the cervicothoracic muscles supports the value of this treatment for reducing pain in the affected extremity, and for an approximate duration of 2 months or more. Surgical approaches and newer minimally invasive surgical approaches offer high rates of improvement in select centers.

Hematuria following Botox treatment for upper limb spasticity: a case report

Hematuria is a documented side effect of botulinum toxin injection and has only been reported when it is used for overactive bladder. Here we report a rare case of hematuria following onabotulinumtoxin A (Botox) injection for upper limb spasticity in a 29-year-old male with a history of traumatic brain injury and hemophilia. Hematuria resolved without further complication after self-injection of factor VIII as recommended by his hematologist. Botulinum toxin binds peripheral cholinergic nerve endings to prevent acetylcholine and norepinephrine exocytosis. Studies have shown that both of these compounds are involved in antifibrinolytic activation, suggesting botulinum toxin may play a role in the coagulation cascade by preventing formation of fibrin. This is further supported by resolution of hematuria in our patient after self-injection of factor VIII. As such, botulinum toxin injection may result in mild spontaneous hemorrhage in patients with underlying hematological deficiencies. Further studies are needed to elucidate its effects in coagulation.

The Role of Botulinum Toxin Type A in the Clinical Management of Refractory Anterior Knee Pain

Anterior knee pain is a highly prevalent condition affecting largely young to middle aged adults. Symptoms can recur in more than two thirds of cases, often resulting in activity limitation and reduced participation in employment and recreational pursuits. Persistent anterior knee pain is difficult to treat and many individuals eventually consider a surgical intervention. Evidence for long term benefit of most conservative treatments or surgical approaches is currently lacking. Injection of Botulinum toxin type A to the distal region of vastus lateralis muscle causes a short term functional “denervation” which moderates the influence of vastus lateralis muscle on the knee extensor mechanism and increases the relative contribution of the vastus medialis muscle. Initial data suggest that, compared with other interventions for anterior knee pain, Botulinum toxin type A injection, in combination with an active exercise programme, can lead to sustained relief of symptoms, reduced health care utilisation and increased activity participation. The procedure is less invasive than surgical intervention, relatively easy to perform, and is time- and cost-effective. Further studies, including larger randomized placebo-controlled trials, are required to confirm the effectiveness of Botulinum toxin type A injection for anterior knee pain and to elaborate the possible mechanisms underpinning pain and symptom relief.

Antinociceptive Effects of Transcytosed Botulinum Neurotoxin Type A on Trigeminal Nociception in Rats

We examined the effects of peripherally or centrally administered botulinum neurotoxin type A (BoNT-A) on orofacial inflammatory pain to evaluate the antinociceptive effect of BoNT-A and its underlying mechanisms. The experiments were carried out on male Sprague-Dawley rats. Subcutaneous (3 U/kg) or intracisternal (0.3 or 1 U/kg) administration of BoNT-A significantly inhibited the formalin-induced nociceptive response in the second phase. Both subcutaneous (1 or 3 U/kg) and intracisternal (0.3 or 1 U/kg) injection of BoNT-A increased the latency of head withdrawal response in the complete Freund's adjuvant (CFA)-treated rats. Intracisternal administration of N-methyl-D-aspartate (NMDA) evoked nociceptive behavior via the activation of trigeminal neurons, which was attenuated by the subcutaneous or intracisternal injection of BoNT-A. Intracisternal injection of NMDA up-regulated c-Fos expression in the trigeminal neurons of the medullary dorsal horn. Subcutaneous (3 U/kg) or intracisternal (1 U/kg) administration of BoNT-A significantly reduced the number of c-Fos immunoreactive neurons in the NMDA-treated rats. These results suggest that the central antinociceptive effects the peripherally or centrally administered BoNT-A are mediated by transcytosed BoNT-A or direct inhibition of trigeminal neurons. Our data suggest that central targets of BoNT-A might provide a new therapeutic tool for the treatment of orofacial chronic pain conditions.

Botulinum Toxin in Pediatric Neurology: Switching Lanes From Death to Life

Botulinum neurotoxins are natural molecules produced by anaerobic spore-forming bacteria called Clostradium boltulinum. The toxin has a peculiar mechanism of action by preventing the release of acetylcholine from the presynaptic membrane. Consequently, it has been used in the treatment of various neurological conditions related to muscle hyperactivity and/or spasticity. Also, it has an impact on the autonomic nervous system by acting on smooth muscle, leading to its use in the management of pain syndromes. The use of botulinum toxin in children separate from adults has received very little attention in the literature. This review presents the current data on the use of botulinum neurotoxin to treat various neurological disorders in children.

Botulinum toxin a does not decrease calf pain or improve ROM during limb lengthening: a randomized trial

BACKGROUND

During lower limb lengthening, distraction-induced muscle pain and surrounding joint contractures are frustrating complications for which few effective treatments are available.

QUESTIONS/PURPOSES

We evaluated Botulinum Toxin Type A (BtX-A) injection in the calf muscles during human tibial distraction osteogenesis. We hypothesized that it may decrease calf pain and increase ROM of the surrounding joints by reducing muscle stiffness.

METHODS

Between April 2010 and January 2011, we evaluated 36 patients undergoing bilateral tibia lengthening who met prespecified inclusion criteria. All patients underwent stature lengthening with lengthening over a nail or lengthening and then nailing. BtX-A (200 IU) was injected at the calf muscle only in one leg for each patient and the same amount of sterile normal saline was injected into the other leg as a control. Selection of the leg receiving the toxin was randomized. Clinical evaluation included a VAS score for calf pain and measurement of ROM of the knees and ankles and calf circumference, with evaluations performed in a double-blinded manner. Side-to-side differences were analyzed until the end of consolidation phase. Minimum followup was 24 months (mean, 30 months; range, 24-39 months). The distraction rate and the final length gain were similar in the treated and control limbs. A priori power analysis suggested that 34 legs were required to achieve statistical significance of 0.05 with 80% of power to detect a 50% difference in treatment effect between treatment and control groups.

RESULTS

There were no differences in calf pain, knee and ankle ROM, and maximal calf circumferences between the two legs at each time point.

CONCLUSIONS

Local injection of 200 IU BtX-A at the human calf muscle does not appear to reduce calf pain or help enhance ROM of the knee and ankle during tibial lengthening. However, the small sample size provided sufficient power to detect only relatively large clinical effects; future, larger trials will be needed to determine whether smaller differences are present.

LEVEL OF EVIDENCE

Level II, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

The Use of Complementary and Alternative Medicine in Patients with Migraine

Although many patients with migraine get positive benefits from conventional pharmacological treatments, many others do not benefit sufficiently or experience adverse effects from these treatments. For that reason, these patients usually seek complementary and/or alternative medical (CAM) treatments all over the world. In general, although CAM therapies are not recommended by neurologist in Turkey, most of migraine patients, who do not respond conventional medicine treatments, seek alternative therapy. Acupuncture, botulinum toxin, mind-body interventions, and nutraceutical options are the most popular treatments. In this review, the available evidence for all these treatments will be discussed.

Botulinum toxins: mechanisms of action, antinociception and clinical applications

Botulinum toxin (BoNT) is a potent neurotoxin that is produced by the gram-positive, spore-forming, anaerobic bacterium, Clostridum botulinum. There are 7 known immunologically distinct serotypes of BoNT: types A, B, C1, D, E, F, and G. Clostridum neurotoxins are produced as a single inactive polypeptide chain of 150kDa, which is cleaved by tissue proteinases into an active di-chain molecule: a heavy chain (H) of ∼100 kDa and a light chain (L) of ∼50 kDa held together by a single disulfide bond. Each serotype demonstrates its own varied mechanisms of action and duration of effect. The heavy chain of each BoNT serotype binds to its specific neuronal ecto-acceptor, whereby, membrane translocation and endocytosis by intracellular synaptic vesicles occurs. The light chain acts to cleave SNAP-25, which inhibits synaptic exocytosis, and therefore, disables neural transmission. The action of BoNT to block the release of acetylcholine botulinum toxin at the neuromuscular junction is best understood, however, most experts acknowledge that this effect alone appears inadequate to explain the entirety of the neurotoxin's apparent analgesic activity. Consequently, scientific and clinical evidence has emerged that suggests multiple antinociceptive mechanisms for botulinum toxins in a variety of painful disorders, including: chronic musculoskeletal, neurological, pelvic, perineal, osteoarticular, and some headache conditions.

Can botulinum toxin decrease carer burden in long term care residents with upper limb spasticity? A randomized controlled study

OBJECTIVE

To evaluate whether botulinum toxin can decrease the burden for caregivers of long term care patients with severe upper limb spasticity.

METHOD

This was a double-blind placebo-controlled trial with a 24-week follow-up period.

SETTING

A 250-bed long term care hospital, the infirmary units of 3 regional hospitals, and 5 care and attention homes.

PARTICIPANTS

Participants included 55 long term care patients with significant upper limb spasticity and difficulty in basic upper limb care.

INTERVENTIONS

Patients were randomized into 2 groups that received either intramuscular botulinum toxin A or saline.

MAIN OUTCOME MEASURES

The primary outcome measure was provided by the carer burden scale. Secondary outcomes included goal attainment scale, measure of spasticity by modified Ashworth score, passive range of movement for shoulder abduction, and elbow extension and finger extension. Pain was assessed using the Pain Assessment in Advanced Dementia Scale.

RESULTS

A total of 55 patients (21 men; mean age = 69, SD =18) were recruited. At week 6 post-injection, 18 (60%) of 30 patients in the treatment group versus 2 (8%) of 25 patients in the control group had a significant 4-point reduction of carer burden scale (P < .001). There was also significant improvement in the goal attainment scale, as well as the modified Ashworth score, resting angle, and passive range of movement of the 3 regions (shoulder, elbow, and fingers) in the treatment group which persisted until week 24. There were also fewer spontaneous bone fractures after botulinum toxin injection, although this did not reach statistical significance. No significant difference in Pain Assessment in Advanced Dementia scale was found between the 2 groups. No serious botulinum toxin type A-related adverse effects were reported.

CONCLUSION

Long term care patients who were treated for upper limb spasticity with intramuscular injections of botulinum toxin A had a significant decrease in the caregiver burden. The treatment was also associated with improved scores on patient-centered outcome measures.

Enduring efficacy of Botulinum toxin type A injection for refractory anterior knee pain

PURPOSE

To examine long-term outcomes of Botulinum toxin type A (BoNT-A) injection to vastus lateralis (VL) for refractory anterior knee pain (AKP).

METHODS

Two cohorts (private clinic referrals and previous research participants) injected with BoNT-A for AKP by one neurologist were surveyed retrospectively. Primary outcomes were self-reported benefit, duration of symptom relief, and knee surgery post-injection. Secondary outcomes were changes in utilization of medication/physiotherapy treatment, AKP symptoms and activity limitation.

RESULTS

Overall, average symptom duration was 76 months (SD 98). Responses were available from 46 of 53 private patients. Thirty-eight reported benefit from injection, which was ongoing in 29. Average benefit was 25 months (SD 21). Nine individuals reported symptom recurrence after an average of 14 months (SD 21). Ten had knee surgery post-injection; six of whom had not benefitted from BoNT-A injection. Nineteen of 23 previous research participants were contactable. Initially, all responded favorably to injection. Symptomatic benefit, with an average duration of 44 months (SD 20), persisted in 15. Two subjects proceeded to surgical intervention.

CONCLUSIONS

A single BoNT-A treatment to VL led initially to improved function and relief of knee-related symptoms in 57 of 65 individuals. Improvements were sustained at follow-up, with an average benefit of 34 months (SD 25) post-injection, in 44 of 57 cases.

Prospective randomized trial of 100u vs 200u botox in the treatment of idiopathic overactive bladder

Aim:

To evaluate the clinical outcomes of two different doses of BTX-A in patients with refractory idiopathic overactive bladder.

Patients and Methods:

Thirty nine patients with refractory idiopathic overactive bladder from 1/1/2008 till 30/3/2009 were evaluated in a tertiary care hospital. Patients were evaluated using urodynamic studies, voiding diary, UDI-6 and IIQ-7 questionnaires prior to being prospectively randomized (alternate randomization) to the BTX-A applications and three months after treatment. Voiding diary and residual volume were followed two weeks later. All patients received intradetrusorial injections of BTX-A (Botox, Allergan, Irvine, CA) of 100u or 200u under cystoscopic control on an outpatient basis. The primary endpoint was assessed for the improvement of urodynamic parameters and adverse events at three months after the initial treatment. Secondary end points included urinary frequency, urgency and UUI episodes as assessed by voiding diary and QoL.

Results:

Eleven patients were enrolled to each arm of the study. There were no significant differences in demographic characteristics between the two groups. Urodynamic assessment at the end of the third month showed significant improvement in urodynamic variables in both groups. There was no statistically significant difference in urodynamic parameters and in the voiding diary between the two groups. QOL was significantly improved in both groups with no statistically significant difference between the different doses. Only three patients developed acute urinary retention.

Conclusion:

BTX-A at 100u and 200u appears to improve symptoms, urodynamic parameters and QoL with no statistical significance between the two groups.

Updated perspectives on neurogenic thoracic outlet syndrome

Pain represents a foremost feature of neurogenic thoracic outlet syndrome (NTOS). Similar to other persistent pain conditions, the physical discomfort associated with NTOS can cause severe and often debilitating symptoms. In fact, those suffering from the syndrome report a quality of life impacted as significantly as those with chronic heart failure. This evidence-based literature review focuses on the classification, etiology, clinical presentation, diagnostic measures, and surgical treatment of NTOS, with a focus on nonoperative therapies such as physical modalities, pharmacological therapies, and more contemporary minimally invasive intramuscular treatments with botulinum toxin.

International consensus statement for the use of botulinum toxin treatment in adults and children with neurological impairments--introduction

Botulinum neurotoxin (BoNT) is most commonly used to reduce focal over-activity in skeletal muscle, although newer indications such as management of drooling, pain and tremor are emerging. Treatment of spasticity incorporating BoNT is usually part of an integrated multidisciplinary rehabilitation programme. Prior to initiating this therapy, specific functional limitations, goals and expected outcomes of treatment should be discussed with the patient/carers. Muscle selection and the order/priority of treatment should be agreed. Treatment goals may involve increasing active or passive function or the avoidance of secondary complications or impairment progression. This paper describes the basic science mechanisms of the action of BoNT and subsequent nerve recovery and introduces a supplement comprising the best available evidence and expert opinion from international panels on questions of assessment, indications, BoNT regimen, adjunctive therapy, expected outcomes and recommended monitoring. Speciality areas reviewed include Paediatric Lower Limb Hypertonicity, Paediatric Upper Limb Hypertonicity, Adult Lower Limb Hypertonicity, Adult Upper Limb Hypertonicity, Cervical Dystonia, Drooling and Pain and Niche Indications. There is good quality scientific evidence to support the efficacy of BoNT to reduce muscle over-activity in the limbs secondary to central nervous system disorders in adults and children, to address primary or secondary cervical dystonia, to reduce saliva flow and to treat some pain syndromes. There is emergent evidence for the efficacy of BoNT to reduce focal tremor, to treat other types of pain including neuropathic pain and also to improve function following treatment of focal muscle over-activity.

Peptide-mediated transdermal delivery of botulinum neurotoxin type A reduces neurogenic inflammation in the skin

Release of inflammatory pain mediators from peripheral sensory afferent endings contributes to the development of a positive feedback cycle resulting in chronic inflammation and pain. Botulinum neurotoxin type A (BoNT-A) blocks exocytosis of neurotransmitters and may therefore block the release of pain modulators in the periphery. Subcutaneous administration of BoNT-A (2.5, 5 and 10U) reduced plasma extravasation (PE) caused by electrical stimulation of the saphenous nerve or capsaicin in the rat hindpaw skin (ANOVA, Post hoc Tukey, p<0.05, n=6). Subcutaneous BoNT-A also reduced blood flow changes evoked by saphenous nerve stimulation (ANOVA, Post hoc Tukey, p<0.05, n=6). Subcutaneous BoNT-A had no effect on PE induced by local injection of substance P (SP) or vasodilation induced by local CGRP injection. Although BoNT-A is an effective treatment for a wide range of painful conditions, the toxin's large size necessitates that it be injected at numerous sites. We found that a short synthetic peptide (TD-1) can facilitate effective transdermal delivery of BoNT-A through intact skin. Coadministration of TD-1 and BoNT-A to the hindpaw skin resulted in a significant reduction in PE evoked by electrical stimulation. The findings show that BoNT-A can be administered subcutaneously or topically with a novel transdermal delivery peptide to reduce inflammation produced by activating nociceptors in the skin. Peptide-mediated delivery of BoNT-A is an easy and non-invasive way of administering the toxin that may prove to be useful in clinical practice.

Single CT-guided chemodenervation of the anterior scalene muscle with botulinum toxin for neurogenic thoracic outlet syndrome

OBJECTIVE

To examine pain relief in patients with neurogenic thoracic outlet syndrome (NTOS) after a single, low dose injection of botulinum toxin A (Botox) into the anterior scalene muscle (ASM) under computed tomographic (CT) guidance.

DESIGN

Prospective longitudinal study.

SETTING

Academic medical institution.

PATIENTS

Patients 18 years of age and older were evaluated for potential scalenectomy and first rib resection using the transaxillary approach at the study institution between 2005 and 2008. All patients had failed physical therapy. A total of 29 procedures on 27 participants were studied.

INTERVENTIONS

A single, 20-unit injection of Botox into the ASM under CT-guidance.

OUTCOME MEASURES

Short-form McGill Pain Questionnaire (SF-MPQ) prior to and at 1, 2, and 3 months post-Botox toxin injection.

RESULTS

There was a decline in pain during the 3 months subsequent to Botox injection as noted by the following components of the SF-MPQ: sensory (P = 0.02), total (P = 0.05), visual analog scale (VAS [P = 0.04]), and present pain intensity (PPI) score (P = 0.06). The proportion of patients reporting more intense pain scores did not return to the pre-intervention level at 3 months post-Botox injection.

CONCLUSION

Patients experienced substantial pain relief in months 1 and 2 following a single Botox injection into the ASM under CT guidance. Significant pain reduction was noted for 3 months after Botox injection with respect to both sensory and VAS scores, and the total and PPI scores approximated statistical significance. After 3 months, patients experienced a 29% decrease in the sensory component of their pain as well as an approximate 15% reduction in their VAS score. A single, CT-guided Botox injection into the ASM may offer an effective, minimally invasive treatment for NTOS.

Botulinum toxin in pain treatment

BACKGROUND AND OBJECTIVES

Botulinum toxin (BTX) is one of the most potent bacterial toxins known and its effectiveness in the treatment of some pain syndromes is well known. However, the efficacy of some of its indications is still in the process of being confirmed. The objective of this study was to review the history, pharmacological properties, and clinical applications of BTX in the treatment of pain of different origins.

CONTENTS

Botulinum toxin is produced by fermentation of Clostridium botulinum, a Gram-positive, anaerobic bacterium. Commercially, BTX comes in two presentations, types A and B. Botulinum toxin, a neurotoxin with high affinity for cholinergic synapses, blocks the release of acetylcholine by nerve endings without interfering with neuronal conduction of electrical signals or synthesis and storage of acetylcholine. It has been proven that BTX can selectively weaken painful muscles, interrupting the spasm-pain cycle. Several studies have demonstrated the efficacy and safety of BTX-A in the treatment of tension headaches, migraines, chronic lumbar pain, and myofascial pain.

CONCLUSIONS

Botulinum toxin type A is well tolerated in the treatment of chronic pain disorders in which pharmacotherapy regimens can cause side effects. The reduction in the consumption of analgesics and length of action of 3 to 4 months per dose represent other advantages of its use. However, further studies are necessary to establish the efficacy of BTX-A in chronic pain disorders and its exact mechanism of action, as well as its potential in multifactorial treatments.

Clinical comparisons of botulinum neurotoxin formulations

BACKGROUND

The expanding uses of botulinum neurotoxin (BoNT) for a growing number of clinical indications, including cervical and other dystonias, adult and childhood spasticity, and hyperhidrosis, in conjunction with the emergence of new formulations of BoNT, prompt discussion of the differences in formulations, serotypes, and indications for different neurologic diseases.

REVIEW SUMMARY

This review will evaluate evidence from preclinical studies, prospective treatment studies, and direct comparative trials to discuss the differences among BoNTs and the clinical implications of using these different drugs. Data from these sources indicate that formulations of BoNT are distinct; even the same serotype formulations of BoNT serotype A have different molecular structures and sizes and therapeutic indices (reflected in different safety and efficacy profiles).

CONCLUSION

Taken together, these findings confirm that the different BoNT serotypes, including the different BoNTA formulations, are distinct therapeutic entities.

[Botulinum toxin for postoperative care after limb surgery in cerebral palsy children]

PURPOSE OF THE STUDY

Spasticity can be the cause of pain in cerebral palsy (CP) children who may suffer increased postoperative pain after orthopedic surgery. Moreover, symptoms can be worsened by abnormal movements, cast immobilization or anxiety. Spasticity must therefore be treated after surgery in CP children. A randomized study has demonstrated that when these children undergo surgical tenotomy, preoperative injections of botulinum toxin have a beneficial effect in terms of pain relief. The aim of this study was to assess the benefit regarding pain and comfort provided by preoperative use of botulinum toxin in total-body CP children undergoing bone surgery.

MATERIAL AND METHODS

Two successive groups of nine total-body CP children were compared in a retrospective study. All patients underwent an orthopedic surgery involving a bone or a multilevel procedure. The second group was treated before surgery with multisite injections of botulinum toxin. The main outcome criteria studied were: efficiency and adverse effects of botulinum toxin, duration of hospital stay and pain, length of level III analgesic treatment (morphine), sleep quality, and skin lesions under cast immobilization. The two groups were similar for mean age (8.7+/-2.04 versus 10.9+/-4.37 years) and mean body weight (20+/-5.6 versus 26+/-7.7 kg). Mean botulinum toxin (Botox/kg) in the second group was 11.6 U (range 9.7-14.8). Average time from preoperative botulinum toxin injections to surgery was 27 days (range 23-31).

RESULTS

There was no significant difference between the two groups, except for the botulinum toxin treatment. The Aschworth scale confirmed the clinical efficiency of the preoperative injections, with no adverse effects. After the surgical procedure, all patients but two had cast immobilization (orthopedic traction, in botulinum group). The mean duration was six weeks in both groups. There was no significant difference in duration of the hospital stay: 7.33+/-1.5 versus 7.88+/-1.7 days and duration of level III analgesic treatment (4.33+/-1.9 versus 4.16+/-2.5 days). The duration of pain symptoms decreased significantly from 6.87+/-2.9 to 2.22+/-1.7 days and sleep quality improved from 7/9 to 1/9 patients with disturbed sleep. Four under-cast skin lesions were noted in the first group but none in the bolulinum group.

DISCUSSION

We cannot confirm that botulinum toxin before bone surgery induces lesser consumption of analgesic drugs. Our results do however support the hypothesis that treatment of spasticity using preoperative injections of botulinum toxin decreases the duration of postoperative pain and improves the children's comfort. Moreover, postoperative under-cast skin lesions can be prevented. This work suggests that improved patient comfort and pain relief could be achieved by using multisite botulinum toxin injections before orthopedic surgery in spastic total-body CP children.

Botulinum toxin injection to facilitate rehabilitation of muscle imbalance syndromes in sports medicine

Intramuscular injection of Botulinum toxin to produce reduction of focal muscle overactivity, and localized muscle spasm, has been utilized therapeutically for almost two decades. Muscle overactivity in neurologically normal muscle, where an imbalance exists between a relatively overactive muscle and its less active synergist or antagonist, can inhibit control of the antagonist producing a functional muscle imbalance. This brief review provides an overview of the role of muscle imbalance in sports-related pain and dysfunction, and outlines the potential for intramuscular injection of Botulinum toxin to be used as an adjunct to specific muscle re-education and functional rehabilitation in this patient group. A comprehensive understanding of normal movement and the requirements of the sporting activity are essential to allow accurate diagnosis of abnormal motor patterns and to re-educate more appropriate movement strategies. Therapeutic management of co-impairments may include stretching of tight soft tissues, specific re-education aimed at isolation of the non-dominant weak muscles and improvement in their activation, 'unlearning' of faulty motor patterns, and eventual progression onto functional exercises to anticipate gradual return to sporting activity. Intramuscular injection of Botulinum toxin, in carefully selected cases, provides short term reduction of focal muscle overactivity, and may facilitate activation of relatively 'inhibited' muscles and assist the restoration of more appropriate motor patterns.

Botulinum toxin for pain

Botulinum toxin (BTX) injection is being increasingly used 'off label' in the management of chronic pain. Data support the hypothesis of a direct analgesic effect of BTX, different to that exerted on muscle. Although the pain-reducing effect of BTX is mainly due to its ability to block acetylcholine release at the synapse, other effects on the nervous system are also thought to be involved. BTX affects cholinergic transmission in both the somatic and the autonomic nervous systems. Proposed mechanisms of action of BTX for pain relief of trigger points, muscular spasms, fibromyalgia and myofascial pain include direct action on muscle and indirect effects via action at the neuromuscular junction. Invitro and invivo data have shown that BTX has specific antinociceptive activity relating to its effects on inflammation, axonal transport, ganglion inhibition, and spinal and suprasegmental level inhibition. Our review of the mechanisms of action, efficacy, administration techniques and therapeutic dosage of BTX for the management of chronic pain in a variety of conditions shows that although muscular tone and movement disorders remain the most important therapeutic applications for BTX, research suggests that BTX can also provide benefits related to effects on cholinergic control of the vascular system, autonomic function, and cholinergic control of nociceptive and antinociceptive systems. Furthermore, it appears that BTX may influence the peripheral and central nervous systems. The therapeutic potential of BTX depends mainly on the ability to deliver the toxin to the target structures, cholinergic or otherwise. Evidence suggests that BTX can be administered at standard dosages in pain disorders, where the objective is alteration of muscle tone. For conditions requiring an analgesic effect, the optimal therapeutic dosage of BTX remains to be defined.

Safety and efficacy of botox injection in alleviating post-operative pain and improving quality of life in lower extremity limb lengthening and deformity correction

BACKGROUND

Distraction osteogenesis is the standard treatment for the management of lower limb length discrepancy of more than 3 cm and bone loss secondary to congenital anomalies, trauma or infection. This technique consists of an osteotomy of the bone to be lengthened, application of an external fixator, followed by gradual and controlled distraction of the bone ends. Although limb lengthening using the Ilizarov distraction osteogenesis principle yields excellent results in most cases, the technique has numerous problems and is not well tolerated by many children. The objective of the current study is to determine if Botulinum Toxin A (BTX-A), which is known to possess both analgesic and paralytic actions, can be used to alleviate post-operative pain and improve the functional outcome of children undergoing distraction osteogenesis.

METHODS/DESIGN

The study design consists of a multi centre, randomized, double-blinded, placebo-controlled trial. Patients between ages 5-21 years requiring limb lengthening or deformity correction using distraction will be recruited from 6 different sites (Shriners Hospital for Children in Montreal, Honolulu, Philadelphia and Portland as well as DuPont Hospital for Children in Wilmington, Delaware and Hospital for Sick Children in Toronto, Ont). Approximately 150 subjects will be recruited over 2 years and will be randomized to either receive 10 units per Kg of BTX-A or normal saline (control group) intraoperatively following the surgery. Functional outcome effects will be assessed using pain scores, medication dosages, range of motion, flexibility, strength, mobility function and quality of life of the patient. IRB approval was obtained from all sites and adverse reactions will be monitored vigorously and reported to IRB, FDA and Health Canada.

DISCUSSION

BTX-A injection has been widely used world wide with no major side effects reported. However, to the best of our knowledge, this is the first time BTX-A is being used under the context of limb lengthening and deformity correction.

TRIAL REGISTRATION

NCT00412035.

Evidence-based clinical practice guidelines for interdisciplinary rehabilitation of chronic nonmalignant pain syndrome patients

This is an update to evidence-based practice guidelines for chronic nonmalignant pain syndrome patients first published in 1995 and revised in 1999. The current guidelines recommend interdisciplinary-focused rehabilitation, which is goal-directed and time-limited. Emphasis is placed on educating patients in active self-management techniques that stress maximizing function. Integrated treatment involving medical, psychological/behavioral, physical/occupational therapy, and disability/vocational interventions are recommended on an outpatient basis whenever clinically possible. Patient selection criteria are delineated. Updated references providing evidence-based support for the recommendations are provided, including the use of opioids and sedative-hypnotic medications, injection and block procedures, acupuncture, implantable spinal infusion and stimulation devices, and other invasive spinal surgery procedures such as intradiscal electrothermal therapy. Guideline integration and early detection and intervention with chronic pain syndrome patients are encouraged.

Botulinum toxin for treatment of urinary incontinence due to detrusor overactivity: a systematic review of effectiveness and adverse effects

STUDY DESIGN

Systematic review.

OBJECTIVE

To evaluate effectiveness and adverse effects of botulinum toxin (BTX) for treatment of urinary incontinence (UI) due to detrusor overactivity (DO).

METHODS

Randomized controlled trials published in English before November 2006 were included if they enrolled subjects with UI caused by DO and reported incontinence outcomes.

RESULTS

Three trials totaling 104 subjects with DO refractory to antimuscarinic treatment were included. Two BTX-A trials enrolled primarily patients with NDO secondary to spinal cord injury (SCI) (93%). BTX-A decreased daily UI episodes compared to placebo but the reductions were only significantly different at a few of the time intervals during 24 weeks of follow-up. BTX-A was superior in reducing daily UI episodes in SCI subjects compared to intravesical resiniferatoxin at 12 and 18 months after injections. A small crossover study found BTX-B significantly more effective than placebo in reducing weekly UI episodes in subjects with predominately idiopathic DO. Adverse events (AEs) in BTX-A-treated subjects included urinary tract infection, pain at the injection site, hematuria and autonomic dysreflexia. Four subjects treated with BTX-B reported autonomic AEs.

CONCLUSIONS

BTX may improve UI for subjects with refractory DO. The preferred dose and type of BTX is not known. Long-term efficacy and safety remain unclear and require conduct of larger RCT using standardized and validated clinical outcomes measures.

Efficacy of botulinum toxin type a in the relief of Carpal tunnel syndrome: A preliminary experience

BACKGROUND AND OBJECTIVES

Botulinum toxin type A has been shown to relieve primary headaches, myofascial pain and various neuropathic pains. Carpal tunnel syndrome (CTS) is a common disorder resulting from median nerve compression at the wrist. As reports of botulinum toxin A in the treatment of CTS were limited, this study set out to evaluate the safety and tolerability of botulinum toxin A and its effects on the relief of nerve entrapment and pain in patients with CTS.

METHODS

We conducted an open-label, prospective pilot study using 60 units of botulinum toxin A injected intracarpally in patients with primary CTS. Changes in median nerve conduction velocities, distal latencies, compound muscle action potentials and visual analogue scale (VAS) pain scores were evaluated for 3 months following injection. All adverse experiences, reported spontaneously or observed directly by the investigator, were recorded.

RESULTS

Five women aged 52.2 +/- 2.5 years with 1-2 years' history of CTS were enrolled. Botulinum toxin A was well tolerated and safe. No exacerbated hand weakness was observed in any of the patients. At 3 months, pain was lessened in three patients, remained static in one patient, and was aggravated in one patient. The VAS pain score showed a trend to improvement during the 3 months of follow-up, although it did not reach statistical significance (p = 0.2).

CONCLUSION

Our data suggest long-lasting antinociceptive effects of botulinum toxin A rather than electrophysiological restoration in patients with CTS. Intracarpal injection of botulinum toxin A was shown to be well tolerated and safe. A double-blind, placebo-controlled trial of botulinum toxin A in CTS is warranted since the current study may have been confounded by the placebo effect of intracarpal injection.

New indications for botulinum toxin in rheumatology

Previously known only as a deadly bacterial poison responsible for severe paralysis, botulinum toxin is now a well-recognized therapeutic agent used to relieve involuntary movements, dystonia-related functional impairments, spasticity, and autonomic disorders such as hyperhidrosis. Musculoskeletal pain in patients with rheumatic disorders is among the emerging indications for botulinum toxin therapy. Preliminary data have been obtained in patients with cervical or thoracolumbar myofascial pain syndrome, chronic low back pain, piriformis muscle syndrome, tennis elbow, and stiff person syndrome. At present, the effects of botulinum toxin and its use for pain relief remain controversial. Carefully designed prospective trials are needed to investigate the efficacy and safety of botulinum toxin in pain disorders.

Intravesical injection of botulinum toxin for the treatment of overactive bladder

PURPOSE OF REVIEW

In recent years, botulinum toxin has been investigated for the treatment of various types of lower urinary tract dysfunctions. This review discusses recently published data related to the therapeutic applications of botulinum toxin in overactive bladder as well as the effects of repeated doses, cross-reactivity between different serotypes, and side effects of the toxin injection into the detrusor muscle.

RECENT FINDINGS

Botulinum toxin A has been employed initially in the treatment of neurogenic detrusor overactivity in spinal cord injured patients. Since then, several reports, including a large multicenter study, have confirmed the therapeutic effects of this neurotoxin. The application of botulinum toxin A was extended to the treatment of idiopathic detrusor overactivity and similar results were obtained. Repeated injections of botulinum toxin A had the same sustained benefit. Recently, botulinum toxin B was investigated for the treatments of both neurogenic and idiopathic detrusor overactivity as well as for the management of botulinum toxin A resistant cases.

SUMMARY

Although intradetrusal injection of botulinum toxin is not yet an approved treatment for overactive bladder, available data suggest that botulinum toxin can be a therapeutic option in patients with neurogenic and nonneurogenic detrusor overactivity who are refractory to anticholinergic medications. There is a need, however, for further investigation to determine the optimal conditions for these applications. A randomized, double-blinded, placebo-controlled trial to evaluate the therapeutic effects of botulinum toxin is under way.

Botulinum Toxin Treatment of Adult Spasticity

Injections of botulinum toxin have revolutionised the treatment of focal spasticity. Before their advent, the medical treatment for focal spasticity involved oral anti-spasticity drugs, which had decidedly non-focal adverse effects, and phenol injections. Phenol injections could be difficult to perform, could cause sensory complications and had effects that were of uncertain duration and magnitude. Furthermore, few neurologists knew how to perform them as they were mostly the province of rehabilitation specialists. Botulinum toxin can produce focal, controllable muscle weakness of predictable duration, without sensory adverse effects. Randomised clinical trials (RCTs) involving patients with spasticity resulting from a variety of diseases (mainly stroke and multiple sclerosis) have clearly shown that botulinum toxin type A (Dysport and Botox) can temporarily (for approximately 3 months) reduce spastic hypertonia in the elbow, wrist and finger flexors of the upper limbs, and the hip adductors and ankle plantar flexors in the lower limbs. The clinical benefits from this reduction of neurological impairment are best shown in the upper limb, with less disability of passive function and reduced caregiver burden. In the lower limbs, there is improved perineal hygiene from hip adductor injections. The benefits of reducing ankle plantar flexor tone are less well established. Pain is also reduced, possibly by mechanisms other than muscle weakness. Improved active function has not yet been clearly demonstrated in RCTs, only in open-label trials. The safety of botulinum toxin-A is impressive, with minimal (mainly local) adverse effects. There are little data on the use of botulinum toxin type B (Myobloc or Neurobloc) in spasticity and the only RCT that has examined this did not show tone reduction; dry mouth appeared to be a very common adverse effect. There are also very little data to allow a benefit-risk comparison of phenol and botulinum toxin injections; each have their clinical and technical advantages and disadvantages, and phenol is much less costly than botulinum toxin.

Periorbital pain associated with hemifacial spasms that responded to botulinum toxin treatment and microvascular decompression surgery: a case report

Periorbital pain is unusual in patients with blepharospasms. We report a patient with hemifacial spasms who presented with severe ipsilateral periorbital aching pain. After treatment with botulinum toxin type A, the left hemifacial spasms and left periorbital pain improved temporarily. Microvascular decompression surgery was then performed for the facial spasms. The patient's left hemifacial spasms disappeared immediately after the operation, and his left periorbital pain was also totally resolved.

Conformational sampling of the botulinum neurotoxin serotype a light chain: implications for inhibitor binding

Botulinum neurotoxins (BoNTs) are the most potent of the known biological toxins, and consequently are listed as category A biowarfare agents. Currently, the only treatments against BoNTs include preventative antitoxins and long-term supportive care. Consequently, there is an urgent need for therapeutics to counter these enzymes--post exposure. In a previous study, we identified a number of small, nonpeptidic lead inhibitors of BoNT serotype A light chain (BoNT/A LC) metalloprotease activity, and we identified a common pharmacophore for these molecules. In this study, we have focused on how the dynamic movement of amino acid residues in and surrounding the substrate binding cleft of the BoNT/A LC might affect inhibitor binding modes. The X-ray crystal structures of two BoNT/A LCs (PDB refcodes=3BTA and 1E1H) were examined. Results from these analyses indicate that the core structural features of the examined BoNT/A LCs, including alpha-helices and beta-sheets, remained relatively unchanged during 1 ns dynamics trajectories. However, conformational flexibility was observed in surface loops bordering the substrate binding clefts in both examined structures. Our analyses indicate that these loops may possess the ability to decrease the solvent accessibility of the substrate binding cleft, while at the same time creating new residue contacts for the inhibitors. Loop movements and conformational/positional analyses of residues within the substrate binding cleft are discussed with respect to BoNT/A LC inhibitor binding and our common pharmacophore for inhibition. The results from these studies may aid in the future identification/development of more potent small molecule inhibitors that take advantage of new binding contacts in the BoNT/A LC.

Botulinum toxin in clinical practice

Botulinum toxin, the most potent biological toxin, has become a powerful therapeutic tool for a growing number of clinical applications. This review draws attention to new findings about the mechanism of action of botulinum toxin and briefly reviews some of its most frequent uses, focusing on evidence based data. Double blind, placebo controlled studies, as well as open label clinical trials, provide evidence that, when appropriate targets and doses are selected, botulinum toxin temporarily ameliorates disorders associated with excessive muscle contraction or autonomic dysfunction. When injected not more often than every three months, the risk of blocking antibodies is slight. Long term experience with this agent suggests that it is an effective and safe treatment not only for approved indications but also for an increasing number of off-label indications.

Regulation of calcitonin gene-related peptide secretion from trigeminal nerve cells by botulinum toxin type A: implications for migraine therapy

OBJECTIVES

To determine the effect of botulinum toxin type A on calcitonin gene-related peptide secretion from cultured trigeminal ganglia neurons.

BACKGROUND

The ability of botulinum toxins to cause muscle paralysis by blocking acetylcholine release at the neuromuscular junction is well known. Previous studies and clinical observations have failed to demonstrate sensory changes related to botulinum toxins or the disease of botulism. Recent studies, however, have suggested that botulinum toxin type A injected into pericranial muscles may have a prophylactic benefit in migraine. This observation has renewed the debate of a mechanism of sensory inhibition mediated by botulinum toxin type A.

METHODS

Primary cultures of rat trigeminal ganglia were utilized to determine whether botulinum toxin type A could directly decrease the release of calcitonin gene-related peptide, a neuropeptide involved in the underlying pathophysiology of migraine. Untreated cultures or cultures stimulated with a depolarizing stimulus (potassium chloride) or capsaicin, an agent known to activate sensory C fibers, were treated for 3, 6, or 24 hours with clinically effective doses of botulinum toxin type A or a control vehicle. The amount of calcitonin gene-related peptide secreted into the culture media following the various treatments was determined using a specific radioimmunoassay.

RESULTS

A high percentage (greater than 90%) of the trigeminal ganglia neurons present in 1- to 3-day-old cultures was shown to express calcitonin gene-related peptide. Treatment with depolarizing stimuli (potassium chloride), a mixture of inflammatory agents, or capsaicin caused a marked increase (4- to 5-fold) in calcitonin gene-related peptide released from the trigeminal neurons. Interestingly, overnight treatment of trigeminal ganglia cultures with therapeutic concentrations of botulinum toxin type A (1.6 or 3.1 units) did not affect the amount of calcitonin gene-related peptide released from these neurons. The stimulated release of calcitonin gene-related peptide following chemical depolarization with potassium chloride or activation with capsaicin, however, was greatly repressed by the botulinum toxin, but not by the control vehicle. A similar inhibitory effect of overnight treatment with botulinum toxin type A was observed with 1.6 and 3.1 units. These concentrations of botulinum toxin type A are well within or below the range of tissue concentration easily achieved with a local injection. Incubation of the cultures with toxin for 24, 6, or even 3 hours was very effective at repressing stimulated calcitonin gene-related peptide secretion when compared to control values.

CONCLUSIONS

These data provide the first evidence that botulinum toxin type A can directly decrease the amount of calcitonin gene-related peptide released from trigeminal neurons. The results suggest that the effectiveness of botulinum toxin type A in the treatment of migraine may be due, in part, to its ability to repress calcitonin gene-related peptide release from activated sensory neurons.

The Therapeutic Potential of Botulinum Toxin

BACKGROUND

Botulinum toxin type A (BTX-A; commercial preparation BOTOX) is most well known for its effect on muscle contraction because of the BTX binding to the presynaptic nerve terminal, inhibiting the release of acetylcholine (ACH). The therapeutic benefit of BTX-A, however, can also be isolated to pain relief alone, suggesting that BTX-A also works through additional modes of action.

OBJECTIVE

This article provides insight by an experienced physician into four different case reports. Each case demonstrates the therapeutic potential of BTX-A and the possibility of a different mechanism of action for BTX other than the inhibition of ACH release.

RESULTS

Four patients, each with different symptoms such as relapsing-remitting multiple sclerosis, postherpetic neuralgia, peripheral neuropathy, and severe tingling caused by herniation of cervical vertebrae at the level of C8, were treated with BOTOX, and their symptoms were alleviated.

CONCLUSIONS

The BTX-A mechanism providing pain relief is hypothesized to be something other than muscle relaxation by inhibiting the release of ACH at the neuromuscular juncture, such as inhibition of the release of substance P or the blocking of autonomic pathways, etc. This article is intended to continue to keep physicians using this substance for dermatologic indications aware of the potential unsuspected effects.

Evaluation of treatments for myofascial pain syndrome and fibromyalgia

Myofascial pain syndrome (MPS) and fibromyalgia (FM) are complex conditions and pose significant challenges to clinicians and patients. This chapter explores available treatments for MPS and FM in the context of pathophysiology, clinical evidence, and experimental support. This information may prove to be helpful in designing individualized treatment for patients with these complex syndromes. New treatments should be critically and carefully evaluated as they appear.