Corrugator Muscle Activity Associated with Pressure Pain in Adults with Neck/Shoulder Pain

Background and Objectives: No studies have reported corrugator muscle activity associated with pain in people with pain. This study aimed to develop an objective pain assessment method using corrugator muscle activity with pressure pain stimulation to the skeletal muscle. Methods: Participants were 20 adults (a mean ± SD age of 22.0 ± 3.1 years) with chronic neck/shoulder pain. Surface electromyography (sEMG) of corrugator muscle activity at rest (baseline) and without and with pressure pain stimulation applied to the most painful tender point in the shoulder was recorded. Participants evaluated the intensity of the neck/shoulder pain and the sensory and affective components of pain with pressure stimulation using a visual analogue scale (VAS). The percentages of integrated sEMG (% corrugator activity) without and with pressure pain stimulation to the baseline integrated sEMG were compared, and the relationships between the % corrugator activity and the sensory and affective components of pain VAS scores were evaluated. Results: Without pressure stimulation, an increase in corrugator muscle activity due to chronic neck/shoulder pain was not observed. The % corrugator activity with pressure pain stimulation was significantly higher than that without stimulation (p < 0.01). A significant positive correlation between corrugator muscle activity and the affective components of pain VAS scores with pressure stimulation was found (ρ = 0.465, p = 0.039) and a tendency of positive correlation was found for the sensory component of pain VAS scores (ρ = 0.423, p = 0.063). Conclusions: The increase in corrugator muscle activity with pressure pain stimulation to the tender point in adults with chronic neck/shoulder pain was observed, although increased corrugator muscle activity resulting from the chronic neck/shoulder pain was not. These findings suggest that corrugator muscle activity with pressure pain stimulation can be a useful objective indication for tender point sensitivity assessment in the skeletal muscle with pain.

Evaluation of the Safety and Efficacy of a Biosimilar Abobotulinum Toxin Type A in Treating Moderate to Severe Glabellar Lines: A Non-Inferiority Double Blinded Randomized Controlled Trial

BACKGROUND

Injection of botulinum toxin for cosmetic purposes is a well-established practice.

OBJECTIVES

This study was conducted to compare the safety and efficacy of Dyston^® (investigational biosimilar abobotulinumtoxinA) with Dysport^® (abobotulinumtoxinA, Ipsen) in the treatment of moderate to severe glabellar lines.

METHODS

Out of 193 screened subjects, 126 volunteers with moderate to severe glabellar lines fulfilling eligibility criteria were randomized in a 1:1 ratio to receive either an intramuscular injection of 40-60 units of Dyston^® or Dysport^® . The primary objective was to test the non-inferiority of Dyston^® compared to Dysport^® as measured by the percentage of volunteers who achieved no or mild glabellar lines at maximum frown assessed by the physicians based on the Glabellar Line Severity Score (GLSS) at day 30. Secondary endpoints included the improvement in the glabellar lines at maximum frown and rest states at days 14, 60, 90 and 120 as well as the side effects of the treatment.

RESULTS

Response rates at maximum frown were 75.44% (43/57) in the Dyston^® group and 76.67% (46/60) in the Dysport^® group on day 30 (P value: 0.88, 95%CI: -14.24 to 16.70, diff: 1.23) as per-protocol set, and were 75.81% (47/62) and 76.19 (48/63) (P value: 0.96, 95%CI: -14.59 to 15.35, diff: 0.3) in the Dyston^® and the Dysport^® groups, respectively, based on modified intention to treat population. Adverse events were similar in both groups and mostly mild and well-tolerated.

CONCLUSION

Treatment of moderate to severe glabellar lines with Dyston^® was effective, tolerable, and non-inferior compared to Dysport^® .

PrabotulinumtoxinA-xvfs for the Treatment of Moderate-to-Severe Glabellar Lines

OBJECTIVE

PrabotulinumtoxinA-xvfs (Jeuveau), a botulinum toxin type A, was approved by the Food and Drug Administration for the temporary improvement in the appearance of moderate-to-severe glabellar lines in February 2019. This article will review phase II and III clinical trials to assess the efficacy, safety, and clinical application of this novel, aesthetic-only drug.

DATA SOURCES

A systematic literature review was performed using the terms "glabellar lines AND prabotulinumtoxinA" in the PubMed database. ClinicalTrials.gov was searched to identify nonpublished studies.

STUDY SELECTION AND DATA EXTRACTION

Articles written in English between November 2019 and June 2020 discussing phase II and phase III clinical trials were evaluated.

DATA SYNTHESIS

By the primary efficacy end point on day 30, more patients achieved a greater than 2-point improvement on the Glabellar Line Scale (GLS) at maximum frown compared with baseline on day 0. The proportions of participants who responded to treatment with prabotulinumtoxinA were 67.5% and 70.4% versus 1.2% and 1.3% in placebo groups across 2 identical clinical trials (P < 0.001). Patients receiving prabotulinumtoxinA experienced greater improvement in GLS at maximum frown on day 30 (87.2%) compared with onabotulinumtoxinA (82.8%) and placebo (4.2%; P < 0.001). PrabotulinumtoxinA was well tolerated across all studies.

RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE

This review provides a detailed analysis of the safety and efficacy of prabotulinumtoxinA-xvfs and includes special considerations to help guide patients and clinicians.

CONCLUSION

PrabotulinumtoxinA is a safe and effective new addition to the repository of available treatments for the appearance of glabellar lines.