The Use of Botulinum Toxin for the Treatment of Chronic Joint Pain: Clinical and Experimental Evidence

Botulinum toxin as an effective treatment for persistent twitching in first toe: a detailed case study

Continuous fasciculation that occurs without weakness is referred to as benign fasciculation. Although generally considered non-threatening, cases that persist can significantly impact an individual's quality of life. This study presents a case of a male patient in his 30s experiencing unyielding twitching localized to the sole of his left foot for 2 years. His medical history was devoid of any notable neuromuscular diseases. Results from electromyography testing were also normal for all parameters. Attempts with pharmacological intervention did not yield any improvement of his condition. Although a nerve block targeting the left tibial nerve managed to reduce the severity of the twitching, it failed to decrease its frequency or provide a lasting solution. In search of a more effective treatment, botulinum toxin was administered via ultrasound guidance into the flexor hallucis and digitorum longus muscles. This approach resulted in a marked reduction in both the frequency and severity of the twitching, enabling the patient to resume his daily activities and achieve restful sleep without experiencing any adverse effects. Through this case, the efficacy of botulinum toxin injections as a treatment for intractable twitching is underscored, offering valuable insights into potential therapeutic strategies for similar clinical presentations.

Intraarticular botulinum toxin type A versus corticosteroid or hyaluronic acid for painful knee osteoarthritis: A meta-analysis of head-to-head randomized controlled trials

Intraarticular botulinum toxin type A (BTA) has been shown to be effective for painful knee osteoarthritis (KOA), while the efficacy and safety of intraarticular BTA compared to corticosteroid and hyaluronic acid (HA) remains unknown. A meta-analysis was performed to compare. A search was conducted in Medline (PubMed), CENTER (Cochrane Library), Embase (Ovid), Web of Science, Wanfang, and CNKI to find head-to-head randomized controlled trials (RCTs) directly compare the efficacy and safety between intraarticular BTA and intraarticular corticosteroid or HA for patients with painful KOA. The Cochrane Q test and estimation of I2 were used to assess heterogeneity among studies. After incorporating heterogeneity, a random-effects model was employed for data pooling. Overall, six RCTs involving 348 adults with KOA were included. Intraarticular BTA showed similar efficacy with corticosteroid as evidenced by the changes of pain visual analog scale (VAS: -0.35 [-0.97, 0.28]), total Western Ontario McMaster Universities Arthritis Index (WOMAC: 0.28 [-4.13, 4.69]), and WOMAC for pain (0.64 [-0.42, 1.70]), stiffness (-0.02 [-0.54, 0.50]), and function (0.00 [-2.99, 3.00]). Intraarticular BTA was shown to be more effective than HA in improving pain VAS (-1.31 [-1.97, -0.64]) and WOMAC for pain (-4.81 [-8.73, -0.89]), while the influence on WOMAC for knee stiffness (-1.01 [-4.43, 2.41]) and knee function (-1.86 [-6.71, 2.99]) were similar between groups. No serious adverse events were reported. Evidence from pilot RCTs suggests that intraarticular BTA may confer similar efficacy to corticosteroid for KOA, while BTA may be superior to HA for improving knee pain.

Botulinum Toxin and Percutaneous Needle Electrolysis for the Treatment of Chronic Masticatory Myalgia

Botulinum toxin type A (BTA) is applied in muscle hyperactivity disorders and injected into affected muscles, producing deep and persistent muscle relaxation. Several multidisciplinary groups investigated the treatment of temporomandibular disorders for several years, and there is currently some data on the beneficial effects of BTA in specific cases of chronic masticatory myalgia. Percutaneous needle electrolysis (PNE), which applies a low-intensity galvanic current to promote tissue regeneration, has been shown to be effective in reducing pain and improving masticatory function. The purpose of this study was to investigate the efficacy and safety of BTA and to assess whether its application in patients with localized masticatory myalgia can significantly reduce pain and improve function compared to a group treated with PNE. Fifty-two patients with long-term refractory masticatory myalgia were randomly assigned to two groups. The BTA group (n = 26) received a bilateral botulinum toxin injection and the PNE group (n = 26) received percutaneous electrolysis. The dose of BTA injected was 100 units distributed among the main primary masticatory muscles, and PNE was administered at 0.5 mA/3 s/3 consecutive times in a single session. Patient assessments were performed prior to treatment and one, two, and three months after treatment. The results revealed good therapeutic response in both groups. In the long term, both BTA and PNE showed high efficacy and safety in reducing pain and improving muscle function for the treatment of chronic masticatory myalgia. This improvement was sustained over a three-month period in both groups. Therefore, the use of BTA and PNE could be considered a valid and safe therapeutic alternative among the available options to treat refractory and localized masticatory myalgia when a better therapeutic response is expected as it demonstrated high efficacy.

The safety of botulinum neurotoxin type A's intraarticular application in experimental animals

In vivo studies of botulinum neurotoxin type A (BoNT-A) enabled characterization of its activity in the nociceptive sensory system separate from its preferred action in motor and autonomic nerve terminals. However, in the recent rodent studies of arthritic pain which employed high intra-articular (i.a.) doses (expressed as a total number of units (U) per animal or U/kg), possible systemic effects have not been conclusively excluded. Herein we assessed the effect of two pharmaceutical preparations, abobotulinumtoxinA (aboBoNT-A, 10, 20, and 40 U/kg corresponding to 0.05, 0.11, and 0.22 ng/kg neurotoxin) and onabotulinumtoxinA (onaBoNT-A, 10 and 20 U/kg corresponding to 0.09 and 0.18 ng/kg, respectively) injected into the rat knee, on safety-relevant readouts: digit abduction, motor performance and weight gain during 14 days post-treatment. The i. a. toxin produced dose-dependent impairment of the toe spreading reflex and rotarod performance, which was moderate and transient after 10 U/kg onaBoNT-A and ≤20 U/kg aboBoNT-A doses, and severe and long-lasting (examined up to 14 days) after ≥20 U/kg of onaBoNT-A and 40 U/kg aboBoNT-A. In addition, lower toxin doses prevented the normal weight gain compared to controls, while higher doses induced marked weight loss (≥20 U/kg of onaBoNT-A and 40 U/kg aboBoNT-A). Commonly employed BoNT-A formulations, depending on the doses, cause local relaxation of the surrounding muscles and systemic adverse effects in rats. Thus, to evade possible toxin unwanted local or systemic spread, careful dosing and motor testing should be mandatory in preclinical behavioral studies, irrespective of the sites and doses of toxin application.

The transient receptor potential channels in rheumatoid arthritis: Need to pay more attention

Rheumatoid arthritis (RA) is characterized by the augment of vascular permeability, increased inflammatory cells infiltration, dysregulated immune cells activation, pannus formation and unbearable pain hyperalgesia. Ca²⁺ affect almost every aspect of cellular functions, involving cell migration, signal transduction, proliferation, and apoptosis. Transient receptor potential channels (TRPs) as a type of non-selective permeable cation channels, can regulate Ca²⁺ entry and intracellular Ca²⁺ signal in cells including immune cells and neurons. Researches have demonstrated that TRPs in the mechanisms of inflammatory diseases have achieved rapid progress, while the roles of TRPs in RA pathogenesis and pain hyperalgesia are still not well understood. To solve this problem, this review presents the evidence of TRPs on vascular endothelial cells in joint swelling, neutrophils activation and their trans-endothelial migration, as well as their bridging role in the reactive oxygen species/TRPs/Ca²⁺/peptidyl arginine deiminases networks in accelerating citrullinated proteins formation. It also points out the distinct functions of TRPs subfamilies expressed in the nervous systems of joints in cold hyperalgesia and neuro-inflammation mutually influenced inflammatory pain in RA. Thus, more attention could be paid on the impact of TRPs in RA and TRPs are useful in researches on the molecular mechanisms of anti-inflammation and analgesic therapeutic strategies.

Clinical Efficacy of Botulinum Toxin in the Treatment of Plantar Fasciitis: A Systematic Review and Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To evaluate the efficacy of botulinum toxin A (BTX-A) for the treatment of plantar fasciitis through a meta-analysis of randomized controlled trials (RCTs) focusing on pain and functional outcomes since current literature has supported a potential benefit of BTX-A.

DATA SOURCES

The MEDLINE, EMBASE, Web of Science, and Scopus databases were searched until December 2020 for RCTs reporting the effects of BTX-A injections on plantar fasciitis. The complementary literature search included Cochrane Central Register of Controlled Trials, Clinicaltrials.gov, and greylit.org.

STUDY SELECTION

Only RCTs assessing the effect of BTX-A injections on pain, functional improvement, or plantar fascia thickness in patients with plantar fasciitis were included. Multiple researchers carried out the screening process of the 413 records.

DATA EXTRACTION

Data were extracted independently and in duplicate using a standardized data extraction format. Information was contrasted by a third observer.

DATA SYNTHESIS

BTX-A injections resulted in significant pain relief (mean difference, -2.07 [95% CI, -3.21 to -0.93]; P=.0004; I²=97%) and functional improvement (standardized mean difference, 1.15 [95% CI, 0.39-1.91]; P=.003; I²=87%). A subanalysis indicated that pain relief was sustained at 12 months while functional improvement remained significant after 0-6 months. The results were not affected by a single study after sensitivity analysis. The site of injection and the use or not of ultrasound-guided injections may account for potential sources of interstudy heterogeneity.

CONCLUSIONS

This meta-analysis suggests both a statistically significant and a clinically meaningful improvement on plantar fasciitis symptoms after BTX-A treatment.

The Use of Botulinum Toxin A as an Adjunctive Therapy in the Management of Chronic Musculoskeletal Pain: A Systematic Review with Meta-Analysis

Several studies have investigated the effect of botulinum toxin A (BoNT-A) for managing chronic musculoskeletal pain, bringing contrasting results to the forefront. Thus far, however, there has been no synthesis of evidence on the effect of BoNT-A as an adjunctive treatment within a multimodal approach. Hence, Medline via PubMed, EMBASE, and the Cochrane Library-CENTRAL were searched until November 2020 for randomised controlled trials (RCTs) that investigated the use of BoNT-A as an adjunctive therapy for chronic musculoskeletal pain. The risk of bias (RoB) and the overall quality of the studies were assessed through RoB 2.0 and the GRADE approach, respectively. Meta-analysis was conducted to analyse the pooled results of the six included RCTs. Four were at a low RoB, while two were at a high RoB. The meta-analysis showed that BoNT-A as an adjunctive therapy did not significantly decrease pain compared to the sole use of traditional treatment (SDM -0.89; 95% CI -1.91; 0.12; p = 0.08). Caution should be used when interpreting such results, since the studies displayed very high heterogeneity (I = 94%, p < 0.001). The overall certainty of the evidence was very low. The data retrieved from this systematic review do not support the use of BoNT-A as an adjunctive therapy in treating chronic musculoskeletal pain.

Selective Expression of a SNARE-Cleaving Protease in Peripheral Sensory Neurons Attenuates Pain-Related Gene Transcription and Neuropeptide Release

Chronic pain is a leading health and socioeconomic problem and an unmet need exists for long-lasting analgesics. SNAREs (soluble N-ethylmaleimide-sensitive factor attachment protein receptors) are required for neuropeptide release and noxious signal transducer surface trafficking, thus, selective expression of the SNARE-cleaving light-chain protease of botulinum neurotoxin A (LCA) in peripheral sensory neurons could alleviate chronic pain. However, a safety concern to this approach is the lack of a sensory neuronal promoter to prevent the expression of LCA in the central nervous system. Towards this, we exploit the unique characteristics of Pirt (phosphoinositide-interacting regulator of TRP), which is expressed in peripheral nociceptive neurons. For the first time, we identified a Pirt promoter element and cloned it into a lentiviral vector driving transgene expression selectively in peripheral sensory neurons. Pirt promoter driven-LCA expression yielded rapid and concentration-dependent cleavage of SNAP-25 in cultured sensory neurons. Moreover, the transcripts of pain-related genes (TAC1, tachykinin precursor 1; CALCB, calcitonin gene-related peptide 2; HTR3A, 5-hydroxytryptamine receptor 3A; NPY2R, neuropeptide Y receptor Y2; GPR52, G protein-coupled receptor 52; SCN9A, sodium voltage-gated channel alpha subunit 9; TRPV1 and TRPA1, transient receptor potential cation channel subfamily V member 1 and subfamily A member 1) in pro-inflammatory cytokines stimulated sensory neurons were downregulated by viral mediated expression of LCA. Furthermore, viral expression of LCA yielded long-lasting inhibition of pain mediator release. Thus, we show that the engineered Pirt-LCA virus may provide a novel means for long lasting pain relief.

Treatment of Localized and Referred Masticatory Myofascial Pain with Botulinum Toxin Injection

Botulinum toxin type A (BTA) injection is considered an available alternative treatment for myofascial pain. However, its efficacy in treating masticatory myofascial pain syndrome (MMPS) remains unclear. The purpose of this study was to evaluate whether the BTA injection into the affected muscles would significantly reduce pain and improve function, and to assess its efficacy, safety, and therapeutic indications in a randomized, single-center clinical trial. Sixty patients with MMPS were randomized into three groups evenly to receive a single session injection of saline solution (SS group), lidocaine (LD group), and BTA (BTA group) in the masseter, temporal, and pterygoid muscles after an electromyographic study. Patients’ pain was classified as localized or referred according to the DC/TMD classification. Assessments were performed on pre-treatment, and subsequently, on days 7, 14, 28, 60, 90, and 180. A significant reduction in pain and improvement of mandibular movements was found in the BTA group compared to the SS and LD groups. The response lasted until day 180 and was more intense in patients with localized myalgia and focused myofascial pain than in referred remote pain. No significant adverse reactions were observed. A single BTA injection can be considered an effective treatment option in patients with localized MMPS by reducing pain and improving mandibular movements, which persisted up to 6 months.

Effect of Botulinum Toxin Injection on Asymmetric Lower Face with Chin Deviation

The purpose of this study was to compare the efficacy of botulinum toxin (BoNT) in masseter muscle reduction depending on the amount of chin deviation. Exploring distinctive effects of BoNT relative to the characteristics of facial asymmetry will aid in planning and predicting treatment outcomes. Sixteen adult volunteers were classified into two groups according to the degree of menton deviation observed in posteroanterior cephalograms. Eight had a menton deviation of 3 mm or more and the other eight had less than 3 mm. A total of 25 Units of BoNT was injected into the unilateral masseter muscle of the prominent side for each participant. Changes in the volume and bulkiest height of the lower face on each side were measured with a 3D laser scan at four time points: before and 4, 8, and 12 weeks after the injection. Two-way mixed ANOVA was employed for analyses. The volume and bulkiest height of the injected side decreased over time in both types of asymmetry, with significant differences at each time point. The reductions in the volume and bulkiest height were significantly greater in subjects without chin deviation. The reductions in the volume and bulkiest height of the lower face using BoNT are more effective for subjects without chin deviation.