O'Connor, J.M., Helmer, S.D., Osland, J.S., Cusick, T.E., & Tenofsky, P.L. (2011). Do topical anesthetics reduce periareolar injectional pain before sentinel lymph node biopsy? American Journal of Surgery, 202(6), 707–711; discussion 711–122.doi: 10.1016/j.amjsurg.2011.06.040
To determine whether lidocaine-prilocaine cream decreases injection pain related to sentinel lymph node biopsy
Eligible subjects were randomized to either the treatment or control group, then provided with a syringe that contained either the study medication (lidocaine-prilocaine cream) or a placebo cream that looked identical to it. Subjects also received instructions on how to apply the cream and a copy of the postprocedure survey, which asked patients to evaluate ease of application as well as level of pain. The subjects were to apply the given cream and then a barrier dressing to the area. Patients went to one of three radiology departments to receive an injection of the Tc sulfur colloid for the sentinel lymph node biopsy. Postoperatively, over the telephone, the patients completed the survey with help from a researcher.
Phase of care: active treatment
Triple-blinded prospective randomized placebo-controlled trial
Thirty-nine subjects completed the study. Subjects from both groups rated the cream as easy to apply, and both groups responded similarly in regard to dressing retention. Authors reported no significant difference in median injectional pain scores between the treatment and control groups. Authors noted two trends: The treatment group was more likely than the control group to recommend the cream, and the control group was more likely to rate the injection as painful or extremely painful.
The pain scores of subjects who received the lidocaine-prilocaine cream were not significantly lower than those of the control group.
This study does not indicate that a topical anesthetic, lidocaine-prilocaine cream, had a significant effect on injectional pain; however, the finding may be a consequence of the study design. Further studies, with larger sample sizes and smaller predicted differences in the study groups, may produce a different result.