BACKGROUND AND PURPOSE:

• Williams et al. (Obstetrics & Gynecology, 2020) compared application of lidocaine–prilocaine cream vs lidocaine injection for pain control during vulvar biopsy

METHODS:

• Single-site randomized trial (RCT)
• Participants
  • Undergoing vulvar biopsy
  • Non–hair-bearing surface
• Interventions
  • Lidocaine–prilocaine cream 5% (Eutectic Mixture of Local Anesthetics [EMLA]) | 5 g placed ≥10 minutes prior to procedure
  • Lidocaine injection 1% | 2 ml injected using a 27 guage needle ≥1 minute prior to procedure
• Study design and data analysis
  • Pain was recorded using a 100 mm visual analog scale | 0 mm = no pain and 100mm = worst imaginable pain
  • 3 time points: Baseline | After application of anesthesia | After biopsy
• Primary outcome
  • Highest pain score recorded
• Secondary outcomes
  • Pain score at biopsy
  • Patient experience
  • Tolerability and acceptability
• Statistical analysis – Power and sample size
  • 90% power | Two-sided alpha level of 0.05
  • To detect a 16 mm difference with (SD of 25 mm), sample size of 53 participants required in each treatment arm

RESULTS:

• 37 patients included (trial stopped at interim analysis due to difference in pain scores between groups in favor of cream group)
  • Participant median age was 60 years
  • 19 were randomized to the lidocaine–prilocaine group, 18 to the lidocaine injection group
• Median highest pain score
  • Cream group: 20.0 mm
  • Injection group: 56.5 mm
• Controlling for baseline pain: Cream group experiencing a 25.7 mm lower pain score than injection (95% CI, −45.1 to −6.3; p<0.01)
• Reduced pain scores in cream group vs injection still documented when number of biopsies taken in to account
• Overall median patient experience score also favored cream group (p=0.02)
  • Cream: 2.0 mm
  • Injection group: 17.0 mm
• The difference in pain is perceived prior to biopsy rather than actual biopsy

CONCLUSION:

• In this study group, women who received topical lidocaine–prilocaine cream before vulvar biopsy had a lower maximum pain score and rated their experience better than women who received lidocaine injection
• The authors suggest

Lidocaine–prilocaine cream, alone, should be considered as an anesthetic method for vulvar biopsy in a non–hair-bearing area on an individualized basis after an informed discussion between patients and health care providers.

Learn More – Primary Sources:

Lidocaine–Prilocaine Cream Compared With Injected Lidocaine for Vulvar Biopsy: A Randomized Controlled Trial

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