Cutaneous cooling to manage botulinum toxin injection-associated pain in patients with facial palsy: A randomised controlled trial

Comparison of the Effectiveness of Different Methods for Pain Reduction During Injection Procedures in the Frontalis Muscle

BACKGROUND

Forehead aesthetic injections are a well-known source of discomfort, and many analgesic non-invasive techniques have been proposed to ameliorate pain. However, no study has compared all these techniques for aesthetic purposes. Therefore, this study aimed to compare the effectiveness of topical cream anesthesia, vibratory stimulus, cryotherapy, pressure, and even no intervention, on pain during and immediately after injection, when considering aesthetic injections in the forehead.

METHODS

Seventy patients were selected and had their foreheads divided into 5 parts, which received four different analgesic techniques, and one control zone was added. A numeric rating scale was used to assess pain, two direct questions were asked to evaluate patients' preference and discomfort with the techniques, and the adverse events were quantified. The injections were performed in the same sequence, with three minutes of rest between them and in a single session. Comparisons among analgesic methods for pain relief were performed by the one-way analysis of variance (ANOVA), considering a significance level of 5%.

RESULTS

No significant differences were found among the analgesic methods, and between the methods and the control zone, both during and immediately after the injections (p > 0.05). The preferred method for pain relief was the use of topical anesthetic cream (47%), while the most uncomfortable technique was manual distraction (pressure) (36%). Only one patient reported an adverse event.

CONCLUSIONS

No analgesic method to diminish pain was superior to the others or was better than no method. Nevertheless, the topical anesthetic cream was the preferred technique, causing less discomfort.

LEVEL OF EVIDENCE III

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Injection Cryolipolysis: First-in-human Study

Background

Injection cryolipolysis using an ice slurry has been hypothesized to be a novel method of reducing fat. The present first-in-human pilot study aims to investigate the feasibility, safety, and tolerability of ice slurry injection into human subcutaneous fat.

Methods

Preabdominoplasty subjects were recruited. Baseline measurements and serial follow-up visits following a single ice slurry injection procedure into tissue to be excised during abdominoplasty were performed. Melted ice slurry injection was used as control. Feasibility using standard injection techniques was assessed. Thermal imaging was used to determine cooling efficacy. Safety was assessed by adverse event monitoring. Tolerability was assessed by subject-reported pain score. Histology and ultrasound were monitored for structural changes associated with cryolipolysis.

Results

A single injection of ice slurry was feasible and sufficient to cool adipose below the target temperature (10C). There were no serious adverse events. The most common adverse events were bruising and erythema. The mean pain score for ice slurry-injected sites was 1.9/10 and 1.3/10 in control injection sites. Evidence of cryolipolysis was observed on ultrasound and tissue histology in ice slurry-injected sites.

Conclusions

Ice slurry injections are feasible, with an observed safety and tolerability profile comparable to topical cryolipolysis. The ice slurry can cool tissue to induce cryolipolysis, as observed by thermal imaging, ultrasound, and tissue histology, and is selective for ice-injected sites. No significant changes were observed in control sites. The ice slurry may be a promising candidate to enable more precise, effective, and customizable aesthetic fat reduction that warrants further investigation.

Use of Botulinum Toxin in Orofacial Clinical Practice

Introduction: Botulinum neurotoxin (BoNT) is a potent biological toxin and powerful therapeutic tool for a growing number of clinical orofacial applications. BoNT relaxes striated muscle by inhibiting acetylcholine’s release from presynaptic nerve terminals, blocking the neuromuscular junction. It also has an antinociceptive effect on sensory nerve endings, where BoNT and acetylcholine are transported axonally to the central nervous system. In dentistry, controlled clinical trials have demonstrated BoNT’s efficiency in pathologies such as bruxism, facial paralysis, temporomandibular joint (TMJ) disorders, neuropathic pain, sialorrhea, dystonia and more. Aim: This study’s aim was to conduct a systematic literature review to assess the most recent high-level clinical evidence for BoNT’s efficacy and for various protocols (the toxin used, dilution, dosage and infiltration sites) used in several orofacial pathologies. Materials and methods: We systematically searched the MedLine database for research papers published from 2014 to 2019 with randomly allocated studies on humans. The search included the following pathologies: bruxism, dislocation of the TMJ, orofacial dystonia, myofascial pain, salivary gland disease, orofacial spasm, facial paralysis, sialorrhea, Frey syndrome and trigeminal neuralgia. Results: We found 228 articles, of which only 20 met the inclusion criteria: bruxism (four articles), orofacial dystonia (two articles), myofascial pain (one article), salivary gland disease (one article), orofacial spasm (two articles), facial paralysis (three articles), sialorrhea (four articles) or trigeminal neuralgia (three articles). Discussion: The clinical trials assessed showed variations in the dosage, application sites and musculature treated. Thus, applying BoNT can reduce symptoms related to motor muscular activity in the studied pathologies efficiently enough to satisfy patients. We did not identify the onset of any important side effects in the literature reviewed. We conclude that treatment with BoNT seems a safe and effective treatment for the reviewed pathologies.

Paradoxical Frontalis Activation: An Underrecognized Consequence of Facial Palsy

BACKGROUND

Aberrant reinnervation and synkinesis are common and debilitating after facial palsy. Paradoxical frontalis activation can antagonize eye closure and increase the risk of corneal damage. If recognized, judicious botulinum toxin injection to the affected side may reduce this risk.

METHODS

One hundred consecutive patients with synkinesis were identified from a prospective database. Routine facial view photographs were converted to a standardized scale using iris diameter. The vertical distance from the midpoint of the midcanthal line to the inferior border of the eyebrow was measured bilaterally. A value of p < 0.05 was considered significant.

RESULTS

Eighty-two patients were included, with a median age of 44 years (interquartile range, 33 to 59 years); 59 of the patients were women. The commonest cause was idiopathic (n = 55). The median time since onset of palsy was 13 months (interquartile range, 6.5 to 27 months). There was less midpoint of the midcanthal line to the inferior border of the eyebrow excursion on the synkinetic side of the face (p < 0.001). Twenty-two patients (27 percent) displayed paradoxical frontalis movement on the affected side of their face, with increased midpoint of the midcanthal line to the inferior border of the eyebrow distance (eyebrow raise) when attempting eye closure compared with eyebrow raise (n = 19), and tight eye closure compared with gentle eye closure (n = 3).

CONCLUSIONS

This study highlights the phenomenon of paradoxical frontalis activation during eye closure. This is often underrecognized and may contribute to lagophthalmos. The authors found it to be present in 27 percent of patients with moderate or severe synkinesis. Further dynamic studies are required to understand the relationship among frontalis activity, eye closure, and the effects of its inhibition.