Effect of Needle Size on Pain Perception in Patients Treated With Botulinum Toxin Type A Injections
Bibliographic record
Abstract
IMPORTANCE: Transcutaneous injection through smaller hollow-bore needles may decrease patient discomfort, but current evidence is equivocal. OBJECTIVE: To compare injection discomfort in patients treated with botulinum toxin type A with 30- and 32-gauge needles. DESIGN, SETTING, AND PARTICIPANTS: Split-face, patient- and injector-blinded randomized clinical trial at the dermatology service of an urban university medical center. The 20 participants were women aged 25 to 70 years in good health and with moderate dynamic forehead and glabellar wrinkles. Data were collected from November 20, 2013, through January 16, 2014. Follow-up was complete on January 16, 2014. Data from the per-protocol population were analyzed from July 1 to July 31, 2014. INTERVENTIONS: One side of each patient'sforehead received botulinum toxin type A in saline injected with a 32-gauge needle; the other side received the same treatment injected with a 30-gauge needle. In addition, each patient received randomized injections of saline only to both upper inner arms with the same types of needles. MAIN OUTCOMES AND MEASURES: Primary outcomes included the patient-reported pain rating on a visual analog scale (VAS) on either side of the face and arms and the proportion of patients whose VAS ratings corresponded with more than moderate (ie, clinically significant) pain. The secondary outcome consisted of patient-reported information about the character of the pain at both sites using the expanded and revised version of the Short-Form McGill Pain Questionnaire. RESULTS: All 20 patients completed the study. Overall, facial and arm injections were nominally but not significantly more painful with 30-gauge needles (mean [SD] VAS ratings for the face, 4.16 [2.55] vs 3.41 [2.31], P = .34; for the arm, 1.66 [2.07] vs 1.21 [1.65], P = .45). For facial injections, the likelihood of clinically significant pain (VAS rating, ≥5.4) was significantly greater with 30-gauge needles, which were associated with such pain in 8 patients (40%) compared with the 32-gauge needles, which were associated with such pain in 3 patients (15%) (odds ratio, 3.80 [95% CI, 1.05-13.78]; P = .04). No difference was found in the character of pain associated with needle bore (P > .05 for all comparisons). CONCLUSIONS AND RELEVANCE: For facial injections of neurotoxin in saline, 30-gauge needles were associated with greater incidence of clinically significant pain than 32-gauge needles. For patients prone to experience clinically significant pain with facial injections, use of 32-gauge needles may minimize this discomfort. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01981174.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.014 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".