Anatomic Location Influences Duration of Local Lidocaine Anesthesia in Dermatologic Surgery

Abstract

Background: Although the onset and duration of local anesthetics are well-defined, how the anatomic site influences the duration of local anesthetics has not been well characterized in dermatology.

Objective: To define the duration of local anesthesia by anatomic site.

Materials and methods: This was a prospective study. Adult healthy volunteers and patients undergoing Mohs micrographic surgery were invited to participate. The nose and the shin were chosen to represent highly and poorly vascularized anatomic sites, respectively. A total of 0.5 mL of buffered 1% lidocaine hydrochloride with 1:100,000 epinephrine was injected subcutaneously into each anatomic site of each participant. A pinprick test was used to assess adequate anesthesia until return of baseline sensation or visit completion.

Results: This study enrolled 25 participants. Time to return of sensation was significantly shorter on the nose compared with the shin ( p < .0001). On the nose, there was an association between male sex and shorter time to return of sensation.

Conclusion: Time to return of sensation is significantly shorter on the nasal ala compared with the shin, suggesting that patients may regain sensation sooner on highly vascularized sites. Defining the duration of local anesthetics based on anatomic regions is important for treatment planning in dermatologic procedures.