Comparing Numbing Techniques in Mohs Micrographic Surgery

This study is a prospective, randomized, single-center clinical trial involving adult patients undergoing Mohs micrographic surgery for cutaneous malignancy on the face and scalp. Patients will be randomized into one of two study arms:

• Placebo Nerve Block Group: Placebo regional nerve block with sterile normal saline plus standard local infiltration with 0.45% lidocaine with 1:200,000 epinephrine.
• Experimental Nerve Block Group: Regional nerve block with 0.45% lidocaine with 1:200,000 epinephrine plus standard local infiltration with 0.45% lidocaine with 1:200,000 epinephrine.

Pain scores and other perioperative outcomes will be measured to assess the impact of these anesthetic techniques on patient experience, surgical efficiency, and analgesic efficacy. Pain will be assessed using a validated 0-10 Visual Analog Scale (VAS), where 0 = no pain and 10 = worst pain imaginable. Patients will rate their pain at three time points on a printed VAS scale: (T1) after nerve block, (T2) immediately after completion of local infiltration but before surgical excision, and (T3) at the end of stage 1 of Mohs micrographic surgery. Anxiety will be assessed using a validated 0-10 VAS (0 = no anxiety, 10 = worst anxiety imaginable) at the same three time points (T1, T2, and T3). Anxiety will also be assessed preoperatively (T0). Patients will be instructed on the use of these scales prior to surgery, and outcome assessors blinded to allocation will record responses verbatim at the specified intervals. Subjects will be randomized in a 1:1 ratio to either of the study arms. Randomization will be performed using a computer-generated sequence. Allocation concealment will be maintained through sealed opaque envelopes or electronic assignment by personnel not involved in outcome assessment. The study is double-blind; neither the patient nor the clinical staff assessing outcomes will be aware of the group allocation.

Inclusion criteria

• Age ≥18 years.
• Scheduled to undergo MMS.
• Lesions on the face or scalp, defined as the region superior to the mandibular margin anteriorly, superior to the external occipital protuberance posteriorly, and superior to the mastoid processes laterally.
• Tumor diameter plus anticipated stage 1 MMS margin ≥2 cm in diameter OR any tumor on the ear, lip, nose, or eyelid.
• Ability to complete patient reported outcome measures in English.

Exclusion criteria

• Known allergy or contraindication to lidocaine or epinephrine.
• Chronic opioid use or pre existing pain disorders that may interfere with pain reporting.
• Presence of scar tissue at the anatomic site of local infiltration or nerve block that may alter anesthetic penetration.
• Concurrent multi site Mohs procedure.
• Signs of skin and soft tissue infection at the anatomic site of local infiltration or nerve block.
• Inability to understand or complete pain and satisfaction assessments.
• Pregnant or breastfeeding.
• Use of sedatives or anxiolytics prior to the procedure.