Botulinum toxin A and chronic low back pain: A randomized, double-blind study

Beyond Pain: The Effects of OnabotulinumtoxinA Therapy on Sensitization and Interictal Symptoms in Chronic Migraine

Chronic migraine is a disease with a high burden on patients from both a working and quality of life point of view. The pathophysiology of this subtype of migraine is due to several factors, such as medication overuse. Nevertheless, the detrimental recurring of headache attacks with central and peripheral sensitization plays a central role and explains some additional symptoms complained about by these patients even in the interictal phase. OnabotulinumtoxinA is a therapy indicated for chronic migraine since it has proven to reduce peripheral sensitization, showing even efficacy on central symptoms. The aim of this narrative review is to present the current evidence regarding the effect of OnabotulinumtoxinA on sensitization and interictal symptoms.

Botulinum toxin-A effects on pain, somatosensory and psychosocial features of patients with refractory masticatory myofascial pain: a randomized double-blind clinical trial

The antinociceptive effect of BoNT-A have been well documented in animal studies; however, results of few but well-designed randomized placebo-controlled clinical trials about BoNT-A efficacy in masticatory myofascial pain (MFP) are inconsistent. Therefore, the present randomized, double-blind, placebo-controlled clinical trial evaluated the efficacy of BoNT-A in patients with refractory MFP. Twenty-eight patients with pain reduction of less than 30% despite conservative treatment and with an average pain intensity of > 50 mm on the visual analogue scale (VAS) participated. Patients were randomly assigned to receive a total of 80 U of BoNT-A or saline solution (SS) injected into the masseter and anterior temporalis muscles. Pain intensity (VAS), quantitative sensory testing (QST), conditioned pain modulation (CPM), and psychosocial status were examined. Follow-up was performed at 1 and 6 months. For repeated-measure comparisons between evaluation times, Friedman test with Bonferroni correction was used for pain and somatosensory variables and the Wilcoxon test for the psychosocial variables. The Mann-Whitney test was used for all comparisons between groups. The BoNT-A group had a significant decrease in pain intensity at follow-ups compared with the SS group (p < 0.001). QST assessment revealed higher pressure pain threshold values in the masseter muscle for BoNT-A group compared to SS (p < 0.03) at all follow-ups. No differences were found for mechanical pain threshold and wind-up ratio values (p > 0.05) in the entire study. The BoNT-A group presented the most efficient CPM effect (p < 0.03) only at the 1 month follow-up in the masseter muscle. There was a significant time effect for BoNT-A in all psychosocial variables (p < 0.05) and a drug effect in the Central Sensitization Inventory (p < 0.01), Pittsburgh Sleep Quality Index (p < 0.004), and Healthy Survey 36 (p < 0.05) at 6 months follow-up. The study demonstrates that a single injection-session of BoNT-A has positive effects on the hall pain spectrum of patients with refractory masticatory myofascial pain.

Effect of pronator teres muscle botulinum neurotoxin type-A injection on proximal median nerve entrapment

PURPOSE

We aimed to evaluate the effect of botulinum neurotoxin type-A (Btx-A) injection into the pronator teres muscle in proximal median nerve entrapment (PMNE).

METHODS

Intramuscular injection of 30 IU Btx-A into the pronator teres muscle was performed in 12 patients (14 extremities) diagnosed with PMNE. The injection was made under nerve stimulator control. One patient with thoracic outlet syndrome was excluded from the study and not included in the clinical evaluation. Grip and pinch strength, 2-point discrimination, Q-DASH score, and pain on VAS were evaluated and compared before and 6-8 months after injection. The patients were contacted again by phone after the first and fifth years and asked about PMNE symptomatology.

RESULTS

None of the patients had complications. No significant difference in pinch strength was observed following Btx-A injection, but there was significant improvement in grip strength, 2-point discrimination, and Q-DASH and VAS pain scores.

CONCLUSION

The outcomes of our study were promising: Btx-A injection improved symptoms in patients with PMNE.

LEVEL OF EVIDENCE

Level IV.

An overview of myofascial pain syndrome with a focus on trigger point injection

ABSTRACT

Myofascial pain syndrome (MPS) is a very common condition, with an estimated lifetime prevalence of 85% in the general population. MPS is commonly underdiagnosed or misdiagnosed due to the lack of standardized diagnostic criteria and the symptoms' overlap with those of other musculoskeletal pain conditions. The most notable and bothersome feature of MPS is the presence of myofascial trigger points (MTrPs), hypersensitive areas of muscle commonly characterized as knots, nodules, or bumps that cause strain and pain with and oftentimes without stimulation. A low-risk, low-cost procedure, trigger point injection (TPI) is the gold standard for MPS treatment, and NPs can perform the procedure in an outpatient practice setting. Through administration of TPIs and use of other treatment modalities, primary care NPs can significantly impact the quality of life for those patients affected by acute and chronic MPS. This article aims to educate primary care NPs on MPS diagnosis and provide an overview of treatment options, with a focus on TPI use and administration for MPS relief.

Long-Term Effects of a Single Application of Botulinum Toxin Type A in Temporomandibular Myofascial Pain Patients: A Controlled Clinical Trial

This study assessed the long-term effects of botulinum toxin type A (BoNT-A) in subjective pain, pain sensibility, and muscle thickness in persistent myofascial temporomandibular-disorder pain (MFP-TMD) patients. Fourteen female subjects with persistent MFP received BoNT-A treatment with different doses (10U-25U for temporalis muscle and 30U-75U for masseter muscle). The treatment was injected bilaterally in the masseter and anterior temporalis muscles in a single session. Clinical measurements included: self-perceived pain (VAS), pain sensibility (PPT), and muscles thickness (ultrasonography). Follow-up occurred 1, 3, 6, and 72 months after treatment for VAS and PPT and 1, 3, and 72 months for ultrasonography. For statistical analysis, the Friedman test with the Bonferroni test for multiple comparisons as a post hoc test was used for non-parametric repeated measures comparisons among the evaluation times. A 5% probability level was considered significant in all tests. VAS values presented a significant decrease throughout the study (p < 0.05). Regarding PPT values, a significant increase was found when comparing baseline data with post-treatment follow-ups (p < 0.05), and even though a significant decrease was found in muscle thickness when baseline values were compared with the 1- and 3-months assessments, no differences were found when compared with the 72 months follow-up (p > 0.05). A single injection of BoNT-A presents long-term effects in reducing pain in persistent MFP-TMD patients, and a reversibility of adverse effects on masticatory-muscle thickness.

Botulinum toxin injection strategy of intractable and relapsed piriformis syndrome: A case report

RATIONALE

Piriformis syndrome (PS) is neuromuscular disorder caused by sciatic nerve compression by piriformis muscle and related to sciatic-type pain. When the conservative care fails, local injection or surgery can be also performed into piriformis. In recent years, botulinum toxin (BoNT) has also been considered as a new therapeutic option of piriformis syndrome.

PATIENT CONCERNS

A man in his late 40s came to pain clinic for left low back pain. The symptom was aggravated with sitting position.

DIAGNOSIS

Piriformis syndrome.

INTERVENTIONS

The patient underwent BoNT injection with 100 IU with 2 mL into piriformis muscle for piriformis syndrome treatment, and his pain was relieved. However, it recurred 8 months later. BoNT injection was repeated with 100 IU with 5 mL.

OUTCOMES

At the time of this writing, his pain was reduced for 2 years without any medication.

LESSONS

We report a case of treating relapsed piriformis syndrome with BoNT injection of different dilution volume, suggesting that the higher the dilution volume, the more effective for therapeutic effect of BoNT.

Pain Management and Rehabilitation for Central Sensitization in Temporomandibular Disorders: A Comprehensive Review

Temporomandibular disorders (TMD) are a group of musculoskeletal diseases affecting masticatory muscles and temporomandibular joints (TMJ). In this context, the chronic TMD could be considered as a condition with chronic primary orofacial pain, presenting as myofascial TMD pain or TMJ arthralgia. In this context, myogenous TMD may present overlapping features with other disorders, such as fibromyalgia and primary headaches, characterized by chronic primary pain related to dysfunction of the central nervous system (CNS), probably through the central sensitization. This phenomenon could be defined as an amplified response of the CNS to sensory stimuli and peripheral nociceptive, characterized by hyperexcitability in the dorsal horn neurons in the spinal cord, which ascend through the spinothalamic tract. The main objectives of the management of TMD patients are: decreasing pain, increasing TMJ function, and reducing the reflex masticatory muscle spasm/pain. The first-line treatments are physical therapy, pharmacological drugs, occlusal splints, laser therapy, extracorporeal shockwave therapy, transcutaneous electrical nerve stimulation, and oxygen–ozone therapy. Although all these therapeutic approaches were shown to have a positive impact on the central sensitization of TMD pain, there is still no agreement on this topic in the scientific literature. Thus, in this comprehensive review, we aimed at evaluating the evidence on pain management and rehabilitation for the central sensitization in TMD patients.

Comparative Study of 150 vs. 200 Units of Botulinum Toxin as Treatment for Vaginismus

OBJECTIVE

 To comparatively evaluate the outcome of treatment with 150 versus 200 units (U) of botulinum toxin in achieving pain-free intercourse and relieving muscle contraction in order to allow gynecological examination.

METHODS

 In this comparative prospective observational study, 99 patients with vaginismus were treated with botulinum toxin injections from September 2016 to August 2021. Diagnosis and grading of vaginismus severity were assessed using a Female Sexual Function Index (FSFI) questionnaire. Under local or general anesthesia, botulinum toxin diluted with preservative-free saline (150 U and 200 U) was injected into, above, and below the right and left bulbospongiosus muscle and the lateral submucosal areas of the introitus and perineal body using an insulin syringe. Patients were recalled after 2 weeks, and the postoperative outcome was recorded using a similar preoperative questionnaire.

RESULTS

 Overall, the mean age of patients was 30.2 years. The baseline and clinical characteristics were comparable between the 2 groups (p > 0.05). Significant improvements were seen in the pain and anxiety scores of finger penetration, dilator use, intercourse, and cotton swab in individual groups. The intergroup comparisons between 150 U and 200 U of Botox were not statistically significant (p > 0.05).

CONCLUSION

 Low-dose Botox (150 U) is equally effective as high dose Botox injections (200 U) in vaginismus patients. Therefore, Botox-150 U can be used to treat vaginismus as an alternative to high doses of the same substance.

Multidimensional Effectiveness of Botulinum Toxin in Neuropathic Pain: A Systematic Review of Randomized Clinical Trials

Although botulinum toxin (BoNT) has been suggested as a treatment to counter neuropathic pain, no previous systematic reviews investigated the multidimensional effects of BoNT on pain relief and Health-Related Quality of Life (HR-QoL). The aim of this systematic review is to summarize the current evidence on the effectiveness of BoNT treatment for neuropathic pain, and to characterize its multidimensional effectiveness in order to guide physicians in clinical practice. Five databases were systematically searched up to 4 April 2022, to identify randomized controlled trials satisfying the following criteria: adults suffering from neuropathic pain, BoNT administration, any comparator, multidimensional assessment of pain as primary outcome, HR-QoL, physical function, anxiety and depression, and sleep quality as secondary outcomes. Twelve studies were included. The multidimensional pain scales used were short-form McGill Pain Questionnaire, Neuropathic pain scale, Neuropathic Pain Symptom Inventory, International SCI Pain Basic Data Set, West Haven-Yale Multidimensional Pain Inventory, Brief Pain Inventory, and Douleur Neuropathique 4. These scales highlighted the positive effects of BoNT administration. According to the Jadad scale, all the RCTs included were high-quality studies. BoNT administration might be effectively introduced in the comprehensive management of neuropathic pain. Further research should focus on optimal and cost-effective therapeutic protocols.

Injection Botulinum Toxin A in Treatment of Resistant Chronic Low Back Pain: A Prospective Open-Label Study

Objective

The aim of this study was to evaluate the effect of botulinum toxin A (BTX-A) injection on patients with chronic low back pain (CLBP).

Design

In this open-label prospective study, patients with CLBP who satisfied inclusion and exclusion criteria received 100 units of BTX-A injection. Patients were followed up at four weeks, three months, and six months after injection. Pain and function were assessed with visual analog scale (VAS), Roland-Morris Disability Scale (RMS), and Oswestry Disability Index (ODI) at baseline and subsequent visits.

Results

A total of 19 participants with a mean age of 41.11 years completed the study. Compared to baseline, a significant improvement in all scores was observed that persisted up to six months post-injection (P<0.001). Only two patients reported transient injection site pain that improved over two to three days without any treatment.

Conclusion

BTX-A injection is safe and improves pain and function in patients with resistant CLBP. The effects are more beneficial when the population is more homogenous in diagnosis and devoid of negative predictors for the outcome.

Nonsurgical Approaches to Neuroma Management

Symptomatic neuromas and chronic neuropathic pain are significant problems affecting patients' quality of life and independence that are challenging to treat. These symptoms are due to structural and functional changes that occur peripherally within neuromas, as well as alterations that occur centrally within the brain and spinal cord. A multimodal approach is most effective, with goals to minimize opioid use, to capitalize on the synergistic effects of nonopioid medications and to explore potential benefits of novel adjunctive treatments.

Efficacy, acceptability, and safety of muscle relaxants for adults with non-specific low back pain: systematic review and meta-analysis

OBJECTIVE

To investigate the efficacy, acceptability, and safety of muscle relaxants for low back pain.

DESIGN

Systematic review and meta-analysis of randomised controlled trials.

DATA SOURCES

Medline, Embase, CINAHL, CENTRAL, ClinicalTrials.gov, clinicialtrialsregister.eu, and WHO ICTRP from inception to 23 February 2021.

ELIGIBILITY CRITERIA FOR STUDY SELECTION

Randomised controlled trials of muscle relaxants compared with placebo, usual care, waiting list, or no treatment in adults (≥18 years) reporting non-specific low back pain.

DATA EXTRACTION AND SYNTHESIS

Two reviewers independently identified studies, extracted data, and assessed the risk of bias and certainty of the evidence using the Cochrane risk-of-bias tool and Grading of Recommendations, Assessment, Development and Evaluations, respectively. Random effects meta-analytical models through restricted maximum likelihood estimation were used to estimate pooled effects and corresponding 95% confidence intervals. Outcomes included pain intensity (measured on a 0-100 point scale), disability (0-100 point scale), acceptability (discontinuation of the drug for any reason during treatment), and safety (adverse events, serious adverse events, and number of participants who withdrew from the trial because of an adverse event).

RESULTS

49 trials were included in the review, of which 31, sampling 6505 participants, were quantitatively analysed. For acute low back pain, very low certainty evidence showed that at two weeks or less non-benzodiazepine antispasmodics were associated with a reduction in pain intensity compared with control (mean difference -7.7, 95% confidence interval-12.1 to-3.3) but not a reduction in disability (-3.3, -7.3 to 0.7). Low and very low certainty evidence showed that non-benzodiazepine antispasmodics might increase the risk of an adverse event (relative risk 1.6, 1.2 to 2.0) and might have little to no effect on acceptability (0.8, 0.6 to 1.1) compared with control for acute low back pain, respectively. The number of trials investigating other muscle relaxants and different durations of low back pain were small and the certainty of evidence was reduced because most trials were at high risk of bias.

CONCLUSIONS

Considerable uncertainty exists about the clinical efficacy and safety of muscle relaxants. Very low and low certainty evidence shows that non-benzodiazepine antispasmodics might provide small but not clinically important reductions in pain intensity at or before two weeks and might increase the risk of an adverse event in acute low back pain, respectively. Large, high quality, placebo controlled trials are urgently needed to resolve uncertainty.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019126820 and Open Science Framework https://osf.io/mu2f5/.

Invasive Treatments for Low Back Disorders

OBJECTIVE

This abbreviated version of the American College of Occupational and Environmental Medicine's Low Back Disorders guideline reviews the evidence and recommendations developed for invasive treatments used to manage low back disorders.

METHODS

Comprehensive systematic literature reviews were accomplished with article abstraction, critiquing, grading, evidence table compilation, and guideline finalization by a multidisciplinary expert panel and extensive peer-review to develop evidence-based guidance. Consensus recommendations were formulated when evidence was lacking and often relied on analogy to other disorders for which evidence exists. A total of 47 high-quality and 321 moderate-quality trials were identified for invasive management of low back disorders.

RESULTS

Guidance has been developed for the invasive management of acute, subacute, and chronic low back disorders and rehabilitation. This includes 49 specific recommendations.

CONCLUSION

Quality evidence should guide invasive treatment for all phases of managing low back disorders.

Guidelines for botulinum neurotoxin injections in piriformis syndrome

BACKGROUND

The piriformis muscle is normally involved in piriformis syndrome and can be treated with botulinum neurotoxin using several different injection methods. However, definitive injection guidelines for the muscle have not been reported previously.

AIMS

This study aimed to determine the ideal area for injections based on the intramuscular nerve distribution as obtained using a modified Sihler's staining technique.

MATERIALS AND METHODS

A modified Sihler's method was applied to the piriformis muscle in 15 specimens. The intramuscular arborization areas were identified based on two anatomical landmarks: (a) the lateral border of the sacrum bone and (b) the greater trochanter.

RESULTS

The nerve entry point for both piriformis muscles was found in the area between the lateral border of the sacrum and one-fifth of the distance toward the greater trochanter. The intramuscular nerve distribution for the piriformis muscle had the largest arborization patterns between one-fifth and two-fifths of the distance from the sacrum to the greater trochanter. The piriformis muscle was tendinous from two-fifths of the distance to the greater trochanter.

DISCUSSION

This study has yielded suggested optimal injection locations for the piriformis muscle relative to external anatomical landmarks.

CONCLUSION

Clinicians can use these guidelines to ensure the effectiveness of not only botulinum neurotoxin injections but also other agents such as steroids, anesthetics, and normal saline. These guidelines will also help to avoid adverse outcomes of injection treatments.

Treatment of "plantar fasciitis"/Plantar Heel Pain Syndrome with botulinum toxin - A novel injection paradigm pilot study

Randomized controlled trials over the last two decades, although promising with favorable results, have shown varied efficacy in treatment of "plantar fasciitis" with botulinum toxin injection¹. One reason may be due to conflating the variabilities of plantar heel conditions solely as plantar fasciitis. Plantar Heel Pain Syndrome can be of one or more etiologies and symptoms which refutes the mistaken tendency to categorize all plantar heel pain singularly as either plantar fasciitis or fasciosis. Recognizing that there is likely an interplay of inflammatory, degenerative, and neuropathic etiologic conditions of this often-difficult malady to treat, a novel injection paradigm of botulinum toxin is explored in the treatment of 4 distinct presentations of Plantar Heel Pain Syndrome with encouraging results. Botulinum toxin injection into two intrinsic foot muscles; Abductor Hallucis and Quadratus Plantae at their origins with electrical stimulation is presented as novel method to treat four distinct etiologies of Plantar Heel Pain Syndrome. This method of botulinum toxin injection resulted in significant prolonged improvement of patient function and pain reduction in four variations of Plantar Heel Pain Syndrome. A precise injection paradigm facilitated with direct intrinsic muscle stimulation of the Abductor Hallucis and Quadratus Plantae at their origins may prove to be effective in reducing the disabilities of Plantar Heel Pain Syndrome and its associated pain.

The effect of botulinum toxin A on patients with persistent idiopathic dentoalveolar pain-A systematic review

BACKGROUND

It has been suggested that botulinum toxin A (BONT-A) is a safe and effective treatment in relieving pain in patients with persistent idiopathic dentoalveolar pain (PIDP).

OBJECTIVES

This study aimed to systematically evaluate all the available studies investigating the pain-relieving effects of BONT-A in patients with PIDP.

METHODS

A systematic search with specific search terms was made in PubMed, Web of Science and Scopus. Two authors screened titles and abstracts and selected eligible studies for inclusion in the systematic review. The quality of the studies was evaluated by the 12 items Quality Assessment Tool for Observational studies (Pre-Post) Studies with No Control Group, and the level of evidence was assessed according to GRADE.

RESULTS

Three observational studies of 3695 identified were included (445 overlapping studies; 3247 excluded studies). All studies were uncontrolled observational studies investigating the pain-relieving effect of BONT-A in patients with PIDP. The included studies had a fair quality (moderate risk of bias) and insufficient level of evidence. The pain reducing effect by BONT-A injections was in average 50% or more in two studies, in one study 3 out of 4 patients became almost pain free.

CONCLUSIONS

This systematic review shows that presently the level of scientific evidence is insufficient to evaluate the pain-relieving effect of BONT-A injections in patients with PIDP. There are indications that BONT-A injections could be a possible management option for patients with PIDP that seems to be safe and with few adverse events. There is a need for well-designed placebo-controlled, double-blind RCTs.

Treatment methods for post-traumatic elbow stiffness caused by heterotopic ossification

HYPOTHESIS

Heterotopic ossification (HO) is a common complication of surgically treated elbow fractures that can inhibit range of motion and impair quality of life. Although there are many treatment methods for HO, there is a lack of consensus as to the best option. We hypothesized that contracture release combined with Botox injection would lead to improved functional outcome scores when compared with current treatment methods.

METHODS

A retrospective review was conducted of patients who presented to a single surgeon with HO secondary to elbow fracture between 2005 and 2018. A total of 59 patients were identified who met inclusion criteria. Data were classified into 3 groups: contracture release (control - CR), Botox injection with CR (Botox + CR), and radiation therapy with CR (CR + RT). Range of motion measurements were obtained, including flexion, extension, pronation, and supination.

RESULTS

A total of 30 patients (30 of 59, 50.8%) received CR, 6 (6 of 59, 9.2%) were treated with CR + RT, and 23 (23 of 59, 40.0%) had CR + Botox. There was a significant difference between pre- and postoperative arc of motion for both CR + RT (P < .01) and CR + Botox (P < .01). In addition, there was a significant difference in pre- and postoperative extension for patients who received intraoperative Botox injections (P < .05). There was no significant difference between pre- and postoperative motion nor extension in the CR group.

CONCLUSION

Intraoperative Botox injection with CR is an effective method in the treatment of post-traumatic elbow stiffness caused by HO.

Benefits, Safety, and Adjunct Modality Prevalences of Long-Term Botulinum Toxin Injections for Cervical Dystonia and Myofascial Neck Pain: A Retrospective Cohort Study

Introduction

There is a paucity of long-term treatment benefit and safety data of botulinum toxin A (BTX-A) for cervical dystonia (CD) and myofascial neck pain syndrome (MPS). Additionally, the prevalence of adjunct modality uses during this period is unknown despite evolving practices.

Objective

To assess and compare treatment benefit, safety, and adjunct modality prevalences of long-term BTX-A injections between CD and MPS patients.

Design

Retrospective cohort study.

Setting

Private practice tertiary care clinics in Toronto.

Patients

Convenience sample of 37 (52.9%) CD and 33 (47.1%) MPS patients treated for a mean±SD duration of 7.2±4.3 and 8.3±4.7 years, respectively.

Interventions

BTX-A injections administered at least once yearly, for a duration longer than 1 year.

Main Outcome Measures

Toronto Western Spasmodic Torticollis Rating Scales (TWSTRS) for disability and pain, Patient Global Impression of Change (PGIC) score, time to peak effect, duration of total response, adverse effects, and prevalence of adjunct modalities.

Results

CD patients experienced improvements in TWSTRS disability (17.57±6.79 to 9.81±4.35, p<0.001) and pain (14.61±3.08 to 9.05±3.49, p<0.001) scores as well as PGIC score (52.00%±23.60% to 64.80%±23.60%, p=0.007). MPS patients experienced improvements in TWSTRS disability (15.86±7.70 to 10.07±7.01, p=0.01) and pain (15.25±4.09 to 10.85±4.49, p=0.01) scores. In both cohorts, there were no changes in time to peak effect and duration of total response. Adverse effects were minimal and self-limiting. Prevalences of adjunct modalities used by CD versus MPS patients were 28.13% versus 50.00% for anesthetic procedures, 23.08% versus 15.38% for image-guidance, 65.71% versus 56.25% for pectoralis minor injections, and 47.06% versus 53.13% for cannabis-use.

Conclusion

There were demonstrated and comparable treatment benefit, safety, and adjunct modality prevalences. Our study is the first to demonstrate that long-term BTX-A injections for MPS, although commonly used off-label, can be effective and safe.

A Proposal for Botulinum Toxin Type A Injection Into the Temporal Region in Chronic Migraine Headache

Botulinum toxin type-A (BTX-A) injection for treating chronic migraine (CM) has developed into a new technique covering distinct injection points in the head and neck regions. The postulated analgesic mechanism implies that the injection should be administered to sensory nerves rather than to muscles. This study aimed to determine the topographical site of the auriculotemporal nerve (ATN) and to propose the effective injection points for treating CM. ATNs were investigated on 36 sides of 25 Korean cadavers. The anatomical structures of the ATN were investigated focusing on the temporal region. A right-angle ruler was positioned based on two clearly identifiable orthogonal reference lines based on the canthus and tragus as landmarks, and photographs were taken. The ATN appeared superficially in the anterosuperior region of the tragus. The nerve is located deeper than the superficial temporal artery. And it runs between the artery and the superficial temporal vein. In the superficial layer, it is divided into anterior and posterior divisions. The anterior division runs in a superior direction, while the posterior division runs in front of the ear and the several branches are distributed to the skin. We suggest that the optimal BTX-A injection points for CM are in the temporal region. The first point is about 2 cm anterior and 3 cm superior to two orthogonal reference lines defined based on the tragus and canthus, and the second point is about 4 cm superior to the first point. The third and fourth points are recommended about 2 cm superior to the first point, but respectively 1 cm anterior and posterior to it.

No. 164-Consensus Guidelines for the Management of Chronic Pelvic Pain

OBJECTIVE

To improve the understanding of chronic pelvic pain (CPP) and to provide evidence-based guidelines of value to primary care health professionals, general obstetricians and gynaecologists, and those who specialize in chronic pain.

BURDEN OF SUFFERING

CPP is a common, debilitating condition affecting women. It accounts for substantial personal suffering and health care expenditure for interventions, including multiple consultations and medical and surgical therapies. Because the underlying pathophysiology of this complex condition is poorly understood, these treatments have met with variable success rates.

OUTCOMES

Effectiveness of diagnostic and therapeutic options, including assessment of myofascial dysfunction, multidisciplinary care, a rehabilitation model that emphasizes achieving higher function with some pain rather than a cure, and appropriate use of opiates for the chronic pain state.

EVIDENCE

Medline and the Cochrane Database from 1982 to 2004 were searched for articles in English on subjects related to CPP, including acute care management, myofascial dysfunction, and medical and surgical therapeutic options. The committee reviewed the literature and available data from a needs assessment of subjects with CPP, using a consensus approach to develop recommendations.

VALUES

The quality of the evidence was rated using the criteria described in the Report of the Canadian Task Force on the Periodic Health Examination. Recommendations for practice were ranked according to the method described in that report (Table 1).

RECOMMENDATIONS

The recommendations are directed to the following areas: (a) an understanding of the needs of women with CPP; (b) general clinical assessment; (c) practical assessment of pain levels; (d) myofascial pain; (e) medications and surgical procedures; (d) principles of opiate management; (f) increased use of magnetic resonance imaging (MRI); (g) documentation of the surgically observed extent of disease; (h) alternative therapies; (i) access to multidisciplinary care models that have components of physical therapy (such as exercise and posture) and psychology (such as cognitive-behavioural therapy), along with other medical disciplines, such as gynaecology and anesthesia; G) increased attention to CPP in the training of health care professionals; and (k) increased attention to CPP in formal, high-calibre research. The committee recommends that provincial ministries of health pursue the creation of multidisciplinary teams to manage the condition.

Mechanisms of Botulinum Toxin Type A Action on Pain

Already a well-established treatment for different autonomic and movement disorders, the use of botulinum toxin type A (BoNT/A) in pain conditions is now continuously expanding. Currently, the only approved use of BoNT/A in relation to pain is the treatment of chronic migraines. However, controlled clinical studies show promising results in neuropathic and other chronic pain disorders. In comparison with other conventional and non-conventional analgesic drugs, the greatest advantages of BoNT/A use are its sustained effect after a single application and its safety. Its efficacy in certain therapy-resistant pain conditions is of special importance. Novel results in recent years has led to a better understanding of its actions, although further experimental and clinical research is warranted. Here, we summarize the effects contributing to these advantageous properties of BoNT/A in pain therapy, specific actions along the nociceptive pathway, consequences of its central activities, the molecular mechanisms of actions in neurons, and general pharmacokinetic parameters.

Botulinum Neurotoxin Light Chains Expressed by Defective Herpes Simplex Virus Type-1 Vectors Cleave SNARE Proteins and Inhibit CGRP Release in Rat Sensory Neurons

A set of herpes simplex virus type 1 (HSV-1) amplicon vectors expressing the light chains (LC) of botulinum neurotoxins (BoNT) A, B, C, D, E and F was constructed. Their properties have been assessed in primary cultures of rat embryonic dorsal root ganglia (DRG) neurons, and in organotypic cultures of explanted DRG from adult rats. Following infection of primary cultures of rat embryonic DRG neurons, the different BoNT LC induced efficient cleavage of their corresponding target Soluble N-ethylmaleimide-sensitive-factor Attachment protein Receptor (SNARE) protein (VAMP, SNAP25, syntaxin). A similar effect was observed following infection by BoNT-A LC of organotypic cultures of adult rat DRG. To quantify and compare the functional activities of the different BoNT LC, the inhibition of calcitonin gene-related protein (CGRP) secretion was assessed in DRG neurons following infection by the different vectors. All BoNT-LC were able to inhibit CGRP secretion although to different levels. Vectors expressing BoNT-F LC displayed the highest inhibitory activity, while those expressing BoNT-D and -E LC induced a significantly lower CGRP release inhibition. Cleavage of SNARE proteins and inhibition of CGRP release could be detected in neuron cultures infected at less than one transducing unit (TU) per neuron, showing the extreme efficacy of these vectors. To our knowledge this is the first study investigating the impact of vector-expressed transgenic BoNT LC in sensory neurons.

Low Back Pain

PURPOSE OF REVIEW

This article provides an overview of evaluating and treating low back pain in the outpatient setting.

RECENT FINDINGS

As most cases of acute low back pain have a favorable prognosis, current guidelines on imaging studies recommend conservative treatment for 6 weeks prior to obtaining an MRI if no red flags are present. Of these red flags, a prior history of cancer is the strongest risk factor for a malignant etiology and requires urgent evaluation with MRI. Management of acute low back pain is mainly conservative with oral non-narcotic analgesics and mobilization as the initial recommendations. For patients with radiculopathy, epidural steroids may result in short-term pain relief, but long-term effects are still unclear.

SUMMARY

A systematic, evidence-based approach to the patient with low back pain is key to providing safe and cost-efficient care.

Chronic low back pain: a mini-review on pharmacological management and pathophysiological insights from clinical and pre-clinical data

Globally, low back pain (LBP) is one of the most common health problems affecting humans. The lifetime prevalence of non-specific LBP is approximately 84%, with the chronic prevalence at about 23%. Chronic LBP in humans is defined as LBP that persists for more than 12 weeks without a significant pain improvement. Although there are numerous evidence-based guidelines on the management of acute LBP, this is not the case for chronic LBP, which is regarded as particularly difficult to treat. Research aimed at discovering new drug treatments for alleviation of chronic mechanical LBP is lacking due to the paucity of knowledge on the pathobiology of this condition, despite its high morbidity in the affected adult population. For a debilitating condition such as chronic LBP, it is necessary to assess the sustained effects of pharmacotherapy of various agents spanning months to years. Although many rodent models of mechanical LBP have been developed to mimic the human condition, some of the major shortcomings of many of these models are (1) the presence of a concurrent neuropathic component that develops secondary to posterior intervertebral disc puncture, (2) severe model phenotype, and/or (3) use of behavioural endpoints that have yet to be validated for pain. Hence, there is a great, unmet need for research aimed at discovering new biological targets in rodent models of chronic mechanical LBP for use in drug discovery programs as a means to potentially produce new highly effective and well-tolerated analgesic agents to improve relief of chronic LBP. On a cautionary note, it must be borne in mind that because humans and rats display orthograde and pronograde postures, respectively, the different mechanical forces on their spines add to the difficulty in translation of promising rodent data to humans.

Pharmacotherapy for chronic non-specific low back pain: current and future options

INTRODUCTION

Low back pain is associated with a large burden-of-illness. It is responsible for the most years lived with disability as compared with any other medical condition. A comprehensive overview of the evidence on pharmacological treatment options for chronic low back pain is lacking. This review evaluates the evidence for the benefits and risks of currently available pharmacological treatments for chronic low back pain.

AREAS COVERED

The authors focus on the recent (Cochrane) systematic reviews and meta-analyses of randomized clinical trials covering paracetamol (acetaminophen), NSAIDs, muscle relaxants, antidepressants, anticonvulsants, opioids, and other (new) drugs.

EXPERT OPINION

The overall impression of the efficacy of pharmacological treatments for patients with chronic low back pain is rather sobering. The effects on pain reduction and improvement of function are commonly small to moderate and short lasting when compared to placebo. At the same time, the various types of drugs are not without side-effects. This holds especially true for serious side-effects associated with (prolonged) use of strong opioids. Future studies on patients with chronic back pain should aim to identify subgroups of patients with good response to specific pharmacological treatment to facilitate personalized care.

The Effect of Botulinum Neurotoxin Serotype a Heavy Chain on the Growth Related Proteins and Neurite Outgrowth after Spinal Cord Injury in Rats

(1) Background: The botulinum toxin A (BoNT-A) heavy chain (HC) can stimulate the growth of primary motor neurites. (2) Methods: A recombinant BoNT/A HC was injected locally plus interval intrathecal catheter of BoNT/A HC to rats with ipsilateral semi-dissociated lumbar spinal cord injuries (SCIs). First, 2D gel with a silver nitrate stain was applied to detect the general pattern of protein expression. Growth associated protein 43 (GAP-43) and superior cervical ganglion 10 (SCG10) were chosen to represent the altered proteins, based on their molecular weight and pI, and were used to further detect their expression. Meanwhile, the neuronal processes were measured. The measurements of thermal hyperalgesia and grasp power at the ipsilateral hindlimb were used to evaluate spinal sensory and motor function, respectively. (3) Results: The local injection of BoNT/A HC followed by its intrathecal catheter intervally altered the spinal protein expression pattern after an SCI; protein expression was similar to normal levels or displayed a remarkable increase. The changes in the expression and distribution of phosphorylated growth associated protein 43(p-GAP 43) and superior cervical ganglion 10 (SCG 10) indicated that the administration of BoNT/A HC to the SCI significantly amplified the expression of p-GAP43 and SCG10 (p < 0.05). Meanwhile, the positive immunofluorescent staining for both p-GAP43 and SCG10 was mainly present near the rostral aspect of the injury, both in the cytoplasm and the neuronal processes. Moreover, the outgrowth of neurites was stimulated by the BoNT/A HC treatment; this was evident from the increase in neurite length, number of branches and the percentage of cells with neuronal processes. The results from the spinal function tests suggested that the BoNT/A HC did not affect sensation, but had a large role in improving the ipsilateral hindlimb grasp power (p < 0.05). (4) Conclusions: The local injection with the intermittent intrathecal administration of BoNT/A heavy chain to rats with SCI increased the local expression of GAP-43 and SCG 10, which might be affiliated with the regeneration of neuronal processes surrounding the injury, and might also be favorable to the relief of spinal motor dysfunction.

Botulinum toxin treatment of pain syndromes -an evidence based review

This review evaluates the existing level of evidence for efficacy of BoNTs in different pain syndromes using the recommended efficacy criteria from the Assessment and Therapeutic Subcommittee of the American Academy of Neurology. There is a level A evidence (effective) for BoNT therapy in post-herpetic neuralgia, trigeminal neuralgia, and posttraumatic neuralgia. There is a level B evidence (probably effective) for diabetic neuropathy, plantar fasciitis, piriformis syndrome, pain associated with total knee arthroplasty, male pelvic pain syndrome, chronic low back pain, male pelvic pain, and neuropathic pain secondary to traumatic spinal cord injury. BoNTs are possibly effective (Level C -one class II study) for female pelvic pain, painful knee osteoarthritis, post-operative pain in children with cerebral palsy after adductor release surgery, anterior knee pain with vastus lateralis imbalance. There is a level B evidence (one class I study) that BoNT treatment is probably ineffective in carpal tunnel syndrome. For myofascial pain syndrome, the level of evidence is U (undetermined) due to contradicting results. More high quality (Class I) studies and studies with different types of BoNTs are needed for better understanding of the role of BoNTs in pain syndromes.

Are paraspinous intramuscular injections of botulinum toxin a (BoNT-A) efficient in the treatment of chronic low-back pain? A randomised, double-blinded crossover trial

BACKGROUND

Treatment for patients with chronic low-back pain (LBP) is a public health issue. Intramuscular injections of botulinum toxin A (BoNT-A) have shown an analgesic effect on LBP in two previous randomized controlled studies. The objective of the study was to verify the efficacy of paravertebral injections of BoNT-A in patients with LBP.

METHODS

Patients were included in this phase 3 randomized double-blinded trial comparing the efficacy of BoNT-A versus placebo in a crossover study on LBP. Both groups received 200 units of BoNT-A in paravertebral muscles or a placebo, and vice versa at Day 120. The main judgment criterion was LBP intensity 1 month after the injections, evaluated by using a visual pain scale (VAS). Secondary assessment criteria included: LBP intensity 90 and 120 days after injection day; number of days when an allowed antalgic oral treatment was needed in between each evaluation; functional disability measured by the Quebec Back Pain Disability Scale; quality of life; inability to work; patient satisfaction in relation to the treatment's effect; spinal mobility; and strength of spinal muscles, measured by isokinetic technique.

RESULTS

Nineteen patients completed the study. There was no significant difference between the groups' average LBP during the last 8 days at Day30 (p = 0.97). There was no significant difference between the two groups regarding the secondary assessment criteria (p > 0.05).

CONCLUSIONS

Injections of BoNT-A in the paravertebral muscles were not found to be effective to relieve chronic LBP. The limits of the study are that the dose of BoNT-A used was lower than in other studies, and that the limited number of patients included may explain the negative results.

TRIAL REGISTRATIONS

Identifiers: NCT03181802 . Unique Protocol ID: CHUBX2003.

Alternatives to Opioids in the Pharmacologic Management of Chronic Pain Syndromes: A Narrative Review of Randomized, Controlled, and Blinded Clinical Trials

Chronic pain exerts a tremendous burden on individuals and societies. If one views chronic pain as a single disease entity, then it is the most common and costly medical condition. At present, medical professionals who treat patients in chronic pain are recommended to provide comprehensive and multidisciplinary treatments, which may include pharmacotherapy. Many providers use nonopioid medications to treat chronic pain; however, for some patients, opioid analgesics are the exclusive treatment of chronic pain. However, there is currently an epidemic of opioid use in the United States, and recent guidelines from the Centers for Disease Control (CDC) have recommended that the use of opioids for nonmalignant chronic pain be used only in certain circumstances. The goal of this review was to report the current body of evidence-based medicine gained from prospective, randomized-controlled, blinded studies on the use of nonopioid analgesics for the most common noncancer chronic pain conditions. A total of 9566 studies were obtained during literature searches, and 271 of these met inclusion for this review. Overall, while many nonopioid analgesics have been found to be effective in reducing pain for many chronic pain conditions, it is evident that the number of high-quality studies is lacking, and the effect sizes noted in many studies are not considered to be clinically significant despite statistical significance. More research is needed to determine effective and mechanism-based treatments for the chronic pain syndromes discussed in this review. Utilization of rigorous and homogeneous research methodology would likely allow for better consistency and reproducibility, which is of utmost importance in guiding evidence-based care.

Botulinum Toxin for the Treatment of Neuropathic Pain

Botulinum toxin (BoNT) has been used as a treatment for excessive muscle stiffness, spasticity, and dystonia. BoNT for approximately 40 years, and has recently been used to treat various types of neuropathic pain. The mechanism by which BoNT acts on neuropathic pain involves inhibiting the release of inflammatory mediators and peripheral neurotransmitters from sensory nerves. Recent journals have demonstrated that BoNT is effective for neuropathic pain, such as postherpetic neuralgia, trigeminal neuralgia, and peripheral neuralgia. The purpose of this review is to summarize the experimental and clinical evidence of the mechanism by which BoNT acts on various types of neuropathic pain and describe why BoNT can be applied as treatment. The PubMed database was searched from 1988 to May 2017. Recent studies have demonstrated that BoNT injections are effective treatments for post-herpetic neuralgia, diabetic neuropathy, trigeminal neuralgia, and intractable neuropathic pain, such as poststroke pain and spinal cord injury.

Treatment for chronic low back pain: the focus should change to multimodal management that reflects the underlying pain mechanisms

Chronic low back pain: Chronic pain is the most common cause for people to utilize healthcare resources and has a considerable impact upon patients' lives. The most prevalent chronic pain condition is chronic low back pain (CLBP). CLBP may be nociceptive or neuropathic, or may incorporate both components. The presence of a neuropathic component is associated with more intense pain of longer duration, and a higher prevalence of co-morbidities. However, many physicians' knowledge of chronic pain mechanisms is currently limited and there are no universally accepted treatment guidelines, so the condition is not particularly well managed.

DIAGNOSIS

Diagnosis should begin with a focused medical history and physical examination, to exclude serious spinal pathology that may require evaluation by an appropriate specialist. Most patients have non-specific CLBP, which cannot be attributed to a particular cause. It is important to try and establish whether a neuropathic component is present, by combining the findings of physical and neurological examinations with the patient's history. This may prove difficult, however, even when using screening instruments. Multimodal management: The multifactorial nature of CLBP indicates that the most logical treatment approach is multimodal: i.e. integrated multidisciplinary therapy with co-ordinated somatic and psychotherapeutic elements. As both nociceptive and neuropathic components may be present, combining analgesic agents with different mechanisms of action is a rational treatment modality. Individually tailored combination therapy can improve analgesia whilst reducing the doses of constituent agents, thereby lessening the incidence of side effects.

CONCLUSIONS

This paper outlines the development of CLBP and the underlying mechanisms involved, as well as providing information on diagnosis and the use of a wide range of pharmaceutical agents in managing the condition (including NSAIDs, COX-2 inhibitors, tricyclic antidepressants, opioids and anticonvulsants), supplemented by appropriate non-pharmacological measures such as exercise programs, manual therapies, behavioral therapies, interventional pain management and traction. Surgery may be appropriate in carefully selected patients.

Subcutaneous Botulinum Toxin Injection for Post-Thoracotomy Pain Syndrome in Palliative Care: A Case Report

Post-thoracotomy pain syndrome (PTPS) is a traumatic neuropathy that can affect as many as 50% of patients undergoing thoracotomy. Patients are often refractory to conservative management and may require multiple analgesics for adequate pain control. Botulinum toxin, derived from Clostridium botulinum, has many uses in treating conditions involving spasticity, dystonia, chronic migraine, and a variety of pain disorders including neuropathies. Botulinum toxin type A injections may provide an alternative or adjunct to improve symptom management in patients with PTPS.

Nonparalytic botulinum molecules for the control of pain

BiTox attenuated A-nociceptor-mediated mechanosensitivity in rat models of chronic pain. Plasma extravasation and keratinocyte proliferation were also inhibited but C-fiber nociception was not impaired.

Local injections of botulinum toxins have been reported to be useful not only for the treatment of peripheral neuropathic pain and migraine but also to cause long-lasting muscle paralysis, a potentially serious side effect. Recently, a botulinum A-based molecule (“BiTox”) has been synthesized that retains neuronal silencing capacity without triggering muscle paralysis. In this study, we examined whether BiTox delivered peripherally was able to reduce or prevent the increased nociceptive sensitivity found in animal models of inflammatory, surgical, and neuropathic pain. Plasma extravasation and edema were also measured as well as keratinocyte proliferation. No motor deficits were seen and acute thermal and mechanical nociceptive thresholds were unimpaired by BiTox injections. We found reduced plasma extravasation and inflammatory edema as well as lower levels of keratinocyte proliferation in cutaneous tissue after local BiTox injection. However, we found no evidence that BiTox was transported to the dorsal root ganglia or dorsal horn and no deficits in formalin-elicited behaviors or capsaicin or formalin-induced c-Fos expression within the dorsal horn. In contrast, Bitox treatment strongly reduced A-nociceptor-mediated secondary mechanical hyperalgesia associated with either complete Freund’s adjuvant (CFA)-induced joint inflammation or capsaicin injection and the hypersensitivity associated with spared nerve injury. These results imply that although local release of neuromodulators from C-fibers was inhibited by BiTox injection, C-nociceptive signaling function was not impaired. Taken together with recent clinical data the results suggest that BiTox should be considered for treatment of pain conditions in which A-nociceptors are thought to play a significant role.

Abobotulinum Toxin A in the Treatment of Chronic Low Back Pain

Chronic low back pain is a debilitating condition with a complex and multifactorial pathophysiology. Botulinum neurotoxins (BoNTs) have strong analgesic effects, as shown in both animal models of pain and in human beings. A randomized, double-blind, placebo-controlled, parallel format study to investigate the efficacy of abobotulinum toxin A (aboA) in chronic low back pain was conducted. The study cohort consisted of 18 patients who received 100 units of aboA into each of the five lumbar extensor spinae muscles unilaterally or bilaterally (total dose 500 to 1000 units), and 19 who received normal saline of the same volume. The level of pain and quality of life were assessed using the visual analogue scale (VAS) and three questionnaires including the Oswestry Low Back Pain Disability Questionnaire (OLBPDQ). Patients’ perception of improvement was recorded via patient global impression of change (PGIC). The primary outcome measure, the proportion of responders with VAS of <4 at 6 weeks, was not met, but the data was significantly in favor of aboA at 4 weeks (p = 0.008). The total Oswestry score representing quality of life improved in the aboA group compared to the placebo group (p = 0.0448). Moreover, significantly more patients reported their low back pain as “much improved” in the abobotulinum toxin A group (0.0293).

Interneuronal Transfer and Distal Action of Tetanus Toxin and Botulinum Neurotoxins A and D in Central Neurons

Recent reports suggest that botulinum neurotoxin (BoNT) A, which is widely used clinically to inhibit neurotransmission, can spread within networks of neurons to have distal effects, but this remains controversial. Moreover, it is not known whether other members of this toxin family are transferred between neurons. Here, we investigate the potential distal effects of BoNT/A, BoNT/D, and tetanus toxin (TeNT), using central neurons grown in microfluidic devices. Toxins acted upon the neurons that mediated initial entry, but all three toxins were also taken up, via an alternative pathway, into non-acidified organelles that mediated retrograde transport to the somato-dendritic compartment. Toxins were then released into the media, where they entered and exerted their effects upon upstream neurons. These findings directly demonstrate that these agents undergo transcytosis and interneuronal transfer in an active form, resulting in long-distance effects.

Incobotulinum Toxin-A Improves Post-Surgical and Post-Radiation Pain in Cancer Patients

Cancer patients who undergo surgery or radiation can develop persistent focal pain at the site of radiation or surgery. Twelve patients who had surgery or radiation for local cancer and failed at least two analgesic medications for pain control were prospectively enrolled in a research protocol. Patients were injected up to 100 units of incobotulinum toxin A (IncoA) intramuscularly or subcutaneously depending on the type and location of pain (muscle cramp or neuropathic pain). Two patients passed away, one dropped out due to a skin reaction and another patient could not return for the follow up due to his poor general condition. All remaining 8 subjects (Age 31-70, 4 female) demonstrated significant improvement of Visual Analog Scale (VAS) (3 to 9 degrees, average 3.9 degrees) and reported significant satisfaction in Patients' Global Impression of Change scale (PGIC) (7 out of 8 reported the pain as much improved). Three of the 8 patients reported significant improvement of quality of life.

The Effect of Botulinum Toxin A Injections in the Spine Muscles for Cerebral Palsy Scoliosis, Examined in a Prospective, Randomized Triple-blinded Study

STUDY DESIGN

A prospective, randomized triple-blinded cross-over design treating with either botulinum toxin A (BXT) or saline (NaCl).

OBJECTIVE

To examine the efficacy of BTX treatment in cerebral palsy scoliosis (CPS).

SUMMARY OF BACKGROUND DATA

Intramuscular injections with BTX have been used off label in treating CPS. 1 prospective study has been conducted, demonstrating in both radiological and clinical improvement, whereas showing no side effects or complications.

METHODS

Subjects (brace-treated CPS between 2 and 18 yr) were injected using ultrasonic-guidance with either NaCl or BTX in selected spine muscles with 6 mo intervals (block randomization, sealed envelope). Radiographs of the spine and clinical follow-up were captured before and 6 weeks after each injection. Primary outcome parameter was radiological change in Cobb angle, where a 7° change was regarded as an effect (1 SD). Radiological parameters were measured before and 6 weeks after treatment by 3 experienced doctors separately. Moreover, clinical results were evaluated by the pediatric quality of life score and systematic open questioning of the parents about the child's wellbeing. Subjects, researchers, and monitors were blinded during the trial. Appropriate permissions (2008-004584-19) and no funding were obtained.

RESULTS

16 cerebral palsy patients (GFMCS III-V) with CPS were consecutively included, whereas 6 patients were excluded. There were no drop-outs to follow-up, but 1 possible serious adverse event of pneumonia resulting in death was recorded and the study was terminated. No significant radiological or clinical changes were detected when compared with NaCl injections using Wilcoxon matched pair signed-rank test.

CONCLUSION

No positive radiological or clinical effects were demonstrated by this treatment, except for the parent's initial subjective but positive appraisal of the effect. However, the study was terminated due to 1 possible severe adverse event and scheduled numbers needed to treat (hence power) were not reached.

LEVEL OF EVIDENCE

1.

The effects of intraplantar and intrathecal botulinum toxin type B on tactile allodynia in mono and polyneuropathy in the mouse

BACKGROUND

Mononeuropathies (MNs: nerve ligation) and polyneuropathies (PNs: cisplatin) produce unilateral and bilateral tactile allodynia, respectively. We examined the effects of intraplantar (IPLT) and intrathecal (IT) botulinum toxin B (BoNT-B) on this allodynia.

METHODS

Mice (male c57Bl/6) were prepared with an L5 nerve ligation. Others received cisplatin (IP 2.3 mg/kg/d, every other day for 6 injections). Saline and BoNT-B were administered through the IPLT or IT route. We examined mechanical allodynia (von Frey hairs) before and at intervals after BoNT. As a control, we injected IPLT BoNT-B treated with dithiothreitol to cleave heavy chain from light chain. We measured motor function using acute thermal escape and sensorimotor tests.

RESULTS

MN and PN mice showed a persistent ipsilateral and bilateral allodynia, respectively. IPLT BoNT-B resulted in an ipsilateral dorsal horn reduction in the synaptic protein target of BoNT-B (vesicle-associated membrane protein) and a long-lasting (up to approximately 17 days) reversal of allodynia in PN and MN models. The predominant effect after IPLT delivery was ipsilateral to IPLT BoNT. The effects of IPLT BoNT-B in MN mice were blocked by prior reduction of BoNT-B with dithiothreitol. IT BoNT-B in mice with PN resulted in a bilateral reversal of allodynia. With these dosing parameters, hind paw placing and stepping reflexes were unaltered, and there were no changes in thermal escape latencies. After cisplatin, dorsal root ganglions displayed increases in activation transcription factor 3, which were reduced by IT, but not IPLT BoNT-B.

CONCLUSIONS

BoNT-B given IPLT and IT yields a long-lasting attenuation of the allodynia in mice displaying MN and PN allodynia.

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.

The efficacy of botulinum toxin A in post-mastectomy breast reconstruction: a pilot study

BACKGROUND

Botulinum toxin A has been successfully used in a variety of areas to temporarily obliterate muscle mobility for either functional or aesthetic gain. Tissue expander-based breast reconstruction has been plagued with pain and discomfort.

OBJECTIVE

The purpose of this pilot study was to evaluate the role of a neurotoxin (Botulinum toxin A) in expander-based breast reconstruction.

METHODS

Thirty patients underwent mastectomies with immediate expander or acellular dermal matrix reconstruction. The neurotoxin group (n = 15) received 40 units of neurotoxin (Botulinum toxin A, Allergan, Inc, Irvine, CA) into each pectoralis major muscle through 4 serial injections and the placebo group (n = 15) received 4 serial injections of 0.9% NaCl. All patients were followed over 1 year, and patient demographics, VAS (visual analog score), laterality, office visits, amount of expansion and number of times to full expansion, and amount of narcotics required were recorded. Statistical significance was considered as p < .05.

RESULTS

There were no significant differences between the two groups in terms of age, laterality, expander size, or complications (p = .46-.66). There was a significant difference between the two groups in the VAS score, demonstrating decreased pain in the neurotoxin group (p < .05). In addition, there was a significant increase in the volume of expansion per visit in the neurotoxin group as compared to the placebo group (p < .05). There was no significant difference in narcotic use in the first 3 days after surgery; however, there was a significant decrease in use of narcotics from 7 to 45 days in the neurotoxin group (p < .05). There were no complications associated with the use of the neurotoxin.

CONCLUSIONS

The infiltration of the pectoralis major muscle with neurotoxin in immediate, expander-based reconstruction may be beneficial in reducing pain and expediting expansions.

Delivery systems for the treatment of degenerated intervertebral discs

The intervertebral disc (IVD) is the most avascular and acellular tissue in the body and therefore prone to degeneration. During IVD degeneration, the balance between anabolic and catabolic processes in the disc is deregulated, amongst others leading to alteration of extracellular matrix production, abnormal enzyme activities and production of pro-inflammatory substances like cytokines. The established treatment strategy for IVD degeneration consists of physiotherapy, pain medication by drug therapy and if necessary surgery. This approach, however, has shown limited success. Alternative strategies to increase and prolong the effects of bioactive agents and to reverse the process of IVD degeneration include the use of delivery systems for drugs, proteins, cells and genes. In view of the specific anatomy and physiology of the IVD and depending on the strategy of the therapy, different delivery systems have been developed which are reviewed in this article.

Epidemiology, diagnosis, and treatment of neck pain

Neck pain is the fourth leading cause of disability, with an annual prevalence rate exceeding 30%. Most episodes of acute neck pain will resolve with or without treatment, but nearly 50% of individuals will continue to experience some degree of pain or frequent occurrences. History and physical examination can provide important clues as to whether the pain is neuropathic or mechanical and can also be used to identify "red flags" that may signify serious pathology, such as myelopathy, atlantoaxial subluxation, and metastases. Magnetic resonance imaging is characterized by a high prevalence of abnormal findings in asymptomatic individuals but should be considered for cases involving focal neurologic symptoms, pain refractory to conventional treatment, and when referring a patient for interventional treatment. Few clinical trials have evaluated treatments for neck pain. Exercise treatment appears to be beneficial in patients with neck pain. There is some evidence to support muscle relaxants in acute neck pain associated with muscle spasm, conflicting evidence for epidural corticosteroid injections for radiculopathy, and weak positive evidence for cervical facet joint radiofrequency denervation. In patients with radiculopathy or myelopathy, surgery appears to be more effective than nonsurgical therapy in the short term but not in the long term for most people.

Injecting under pressure: the pain of low CSF pressure headache responsive to botulinum toxin injections

Low intracranial pressure headaches can, at times, be refractory to treatment including multiple blood patches and preventative medications. Imaging studies are often unable to demonstrate a cerebrospinal fluid leak that is causing headache and other associated symptoms. Onabotulinum toxin A (BTX) injection is a treatment that has proven efficacy for the treatment of chronic migraine and potentially other headache disorders. We report a patient with a long standing history of refractory low pressure headaches with brain imaging that demonstrated brain sag, and no CSF leak could be identified. She received no sustained benefit from numerous blood patches, and was unresponsive or intolerant to multiple preventative medications. With BTX treatment, the patient continued to have daily headaches, but her pain intensity improved from an average 7/10 to 3/10. This benefit has been sustained over 7 years. This case suggests that BTX may be an effective treatment for headaches due to low intracranial pressure. It also suggests that the beneficial effects of BTX in the treatment of headaches occur through a direct modulation of the nociceptive system rather than merely induction of pericranial muscle relaxation.

Responder analyses in randomised controlled trials for chronic low back pain: an overview of currently used methods

PURPOSE

To provide an overview and a critical appraisal of the use of responder analyses in published randomised controlled trials (RCTs) of interventions for chronic low back pain (LBP). The methodology used for the analyses, including the justification, as well as the implications of responder analyses on the conclusions was explored.

METHODS

A convenience sample of four systematic reviews evaluating 162 RCTs of interventions for chronic LBP was used to identify individual trials. Randomised trials were screened by two reviewers and included if they performed and reported a responder analysis (i.e. the proportion of participants achieving a pre-defined level of improvement). The cutoff value for responders, the period of follow-up, and the outcome measure used were extracted. Information on how RCT authors justified the methodology of their responder analyses was also appraised.

RESULTS

Twenty-eight articles (17%) using 20 different definitions of responders were included in this appraisal. Justification for the definition of responders was absent in 80% of the articles. Pain was the most frequently used domain for the definition of response (50%), followed by back-specific function (30%) and a combination of pain and function (20%). A reduction in pain intensity ≥50% was the most common threshold used to define responders (IQR 33-60%).

CONCLUSIONS

Few RCTs of interventions for chronic LBP report responder analyses. Where responder analyses are used, the methods are inconsistent. When performing responder analyses authors are encouraged to follow the recommended guidelines, using empirically derived cutoffs, and present results alongside mean differences.