Left/Right Pain Asymmetry With Injectable Cosmetic Treatments for the Face

The efficacy of various interventions as good strategies to reduce pain in botulinum neurotoxin A for wrinkles. A systematic review of the randomized controlled trials (RCTs)

Various topical interventions have been described to minimize botulinum neurotoxin-A (BoNT)-induced pain. The purpose of this study is to conduct a systematic review of relevant randomized controlled trials (RCTs) to compare the efficacy of pain relief methods during BoNT injection. PubMed, Scopus, and Web of Science were searched using "Botox," "Botulinum," or "BTX." We identified RCTs in which BoNT were injected to eliminate wrinkles. The pain score was the study outcome, and pain reduction method was compared with routine one. The meta-analysis was reported using the PRISMA checklist. The Higgins I(I2) statistical model assessed results heterogeneity. Two thousand one hundred and twenty-three articles were identified, thirteen articles eligible. Two hundred and sixty-two healthy volunteers were performed on these RCTs. Meta-analysis evaluated different methods to ease BoNT injection pain, and these methods significantly improved outcomes by 0.23% (95%CI, 0.11-0.46, p = .000). Subgroup analysis based on injection area showed no significant heterogeneity, but heterogeneity decreased when subgroup analysis based on other methods was done (Cochran's Q test = 115.52, p = .0001, I2 = 87.9%). This meta-analysis confirms the effectiveness of pain relief methods during BoNT injection. Evaluation of different methods showed their effectiveness, but finding the best method requires comparative studies, although the role of pH and EMLA has been proven.

Is There an Association Between Lateralization of Chronic Pain in the Body and Depression?

Depression commonly co-occurs with chronic pain and can worsen pain outcomes. Recent theoretical work has hypothesized that pain localized to the left hemibody is a risk factor for worse depression due to overlap in underlying neural substrates. This hypothesis has not been tested a priori. Using a large sample of treatment-seeking adults with mixed-etiology chronic pain (N = 1,185), our cross-sectional study tested whether patients with left-sided pain endorse worse depressive symptoms. We also examined differences in other pain-related functioning measures. We tested 4 comparisons based on painful body areas using the CHOIR body map: 1) only left-sided (OL) versus any right-sided pain; 2) only right-sided (OR) versus any left-sided pain; 3) OL versus OR versus bilateral pain; and 4) more left-sided versus more right-sided versus equal-sided pain. Analysis of variance models showed OL pain was not associated with worse depression (F = 5.50, P = .019). Any left-sided pain was associated with worse depression, though the effect was small (F = 8.58, P = .003, Cohens d = .29). Bilateral pain was associated with worse depression (F = 8.05, P < .001, Cohens d = .24-.33). Regardless of pain location, more body areas endorsed was associated with greater depression. Although a more rigorous assessment of pain laterality is needed, our findings do not support the hypothesis that left-lateralized pain is associated with worse depression. PERSPECTIVE: Pain lateralized to the left side of the body has been hypothesized as a risk factor for worse depression in chronic pain, despite never being tested in a large, real-world sample of patients with chronic pain. Findings showed that more widespread pain, not pain laterality, was associated with worse depression.

Does needle size matter? Effects of micro-hypodermic needle injections of botulinum toxin type A in patients with hemifacial spasm

INTRODUCTION

Botulinum toxin type A (BoNT/A) injections are the first-line treatment for primary hemifacial spasms (HFS), but require frequent painful injections. Although micro-hypodermic needles are commonly used for aesthetic BoNT/A injections to lessen pain and bruising, their benefits in HFS remain unclear.

OBJECTIVE

To compare side effects of BoNT/A injection, specifically pain and bruising, between primary HFS patients who received injections using micro-hypodermic needles (34-G) and those using standard needles (30-G).

METHODS

This cross-over, double-blind, randomised controlled trial involved HFS patients who received BoNT/A injections using either a 34-G or 30-G needle at two visits 12 weeks apart. Primary outcomes, pain and bruising were assessed immediately after injection using the Visual Analogue Scale (VAS) and Short-form McGill Pain Questionnaire (Thai version, SF-MPQ). Bruise assessment was also conducted one week after each injection. Secondary outcomes involved comparing efficacy of BoNT/A between the two types of needles and assessing other complications beyond pain and bruising.

RESULTS

65 HFS patients (47 women and 18 men; mean age 59.46 ± 11.48 years; mean disease duration 5.86 ± 4.16 years) were included in the study. Patients who received 34-G needle injections reported significantly reduced pain, as indicated by VAS, total SF-MPQ scores, and bruise scores, compared to those who received 30-G needle injections (p < 0.001, each). There were no differences in efficacy or occurrence of other complications associated with BoNT/A between the two needle types.

CONCLUSION

In HFS patients, BoNT/A injections using micro-hypodermic needles resulted in reduced pain and bruising, compared to standard needles, while maintaining similar BoNT/A benefits.

Spinal and Cerebral Integration of Noxious Inputs in Left-handed Individuals

Some pain-related information is processed preferentially in the right cerebral hemisphere. Considering that functional lateralization can be affected by handedness, spinal and cerebral pain-related responses may be different between right- and left-handed individuals. Therefore, this study aimed to investigate the cortical and spinal mechanisms of nociceptive integration when nociceptive stimuli are applied to right -handed vs. left -handed individuals. The NFR, evoked potentials (ERP: P45, N100, P260), and event-related spectral perturbations (ERSP: theta, alpha, beta and gamma band oscillations) were compared between ten right-handed and ten left-handed participants. Pain was induced by transcutaneous electrical stimulation of the lower limbs and left upper limb. Stimulation intensity was adjusted individually in five counterbalanced conditions of 21 stimuli each: three unilateral (right lower limb, left lower limb, and left upper limb stimulation) and two bilateral conditions (right and left lower limbs, and the right lower limb and left upper limb stimulation). The amplitude of the NFR, ERP, ERSP, and pain ratings were compared between groups and conditions using a mixed ANOVA. A significant increase of responses was observed in bilateral compared with unilateral conditions for pain intensity, NFR amplitude, N100, theta oscillations, and gamma oscillations. However, these effects were not significantly different between right- and left-handed individuals. These results suggest that spinal and cerebral integration of bilateral nociceptive inputs is similar between right- and left-handed individuals. They also imply that pain-related responses measured in this study may be examined independently of handedness.

A lateralized model of the pain-depression dyad

Chronic pain and depression are two frequently co-occurring and debilitating conditions. Even though the former is treated as a physical affliction, and the latter as a mental illness, both disorders closely share neural substrates. Here, we review the association of pain with depression, especially when symptoms are lateralized on either side of the body. We also explore the overlapping regions in the forebrain implicated in these conditions. Finally, we synthesize these findings into a model, which addresses gaps in our understanding of comorbid pain and depression. Our lateralized pain-depression dyad model suggests that individuals diagnosed with depression should be closely monitored for pain symptoms in the left hemibody. Conversely, for patients in pain, with the exception of acute pain with a known source, referrals in today's pain centers for psychological evaluation should be part of standard practice, within the framework of an interdisciplinary approach to pain treatment.

Comparison of Two Anticoagulants for Pain Associated with Platelet-Rich Plasma Injections

BACKGROUND AND AIM

Platelet-rich plasma (PRP) has long been used in skin rejuvenation and hair loss treatment. Some patients require multiple intradermal injections into the face and scalp, and the way in which these patients process and experience pain differs, depending on the patient. Minimizing pain and discomfort during nonsurgical procedures is essential for patient satisfaction. In our experience, the use of acid citrate dextrose-A (ACD-A) as an anticoagulant caused more patient discomfort than did sodium citrate (Na-citrate) among patients who underwent facial rejuvenation with PRP. The aim of the present study was to evaluate patient-related discomfort in PRP sessions using two different anticoagulants.

MATERIALS AND METHODS

This clinical trial included 10 patients who received facial PRP injections for facial rejuvenation and 10 patients who received PRP injections in their scalps for hair loss. On the application area, half the surface was treated with Na-citrate PRP injections, and the other half was treated with the same amount of ACD-A PRP injections. Neither the doctors who applied the treatment nor the patients were given information about which anticoagulant was used in each area. Immediately after the procedure, the patients were asked to score their pain on each side of the application area on a scale of 1-10 using a visual analog scale (VAS).

RESULTS

PRP injections using Na-citrate as an anticoagulant caused less discomfort on both the face and scalp as compared with that of ACD-A. The outcome was statistically significant.

CONCLUSION

Anticoagulants used in PRP preparation affected patients' pain perceptions during the injections. The sensation of pain with PRP prepared with Na-citrate as an anticoagulant was lower than that of PRP prepared with ACD-A. Further studies are required to evaluate the correlation between anticoagulants used for PRP preparation and pain feelings during injections.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.