In a single-blind, crossover, randomized, controlled trial with 40 participants we aim to demonstrate superior anaesthetic efficacy of lidocaine-23%-tetracaine-7% (IMP2) gel over EMLA 5% cream (IMP1) at comparable safety in sharp wound debridement of chronic leg ulcers.

This is a monocentric investigator initiated trial conducted in the University Hospital Zurich.

In this longitudinal trial, participants receive a sequence of different treatments (treatments on different days) and therefore are randomly assigned to one of two treatment sequences. One-half of participants will first receive IMP1 (first treatment visit, randomized) and then IMP2 (second treatment visit, crossover); the other half of participants the reverse sequence (first treatment visit: IMP2, second treatment visit: IMP1).

Primary Objective: We want to show that IMP 2 (lidocaine-23%-tetracaine-7% gel) is more effective in pain reduction than IMP 1 (EMLA® 5% cream) in sharp wound debridement.

Inclusion Criteria:

• Participants between 18 years and 90 years
• Chronic leg ulcer(s) (duration > 4 weeks) with biofilm or necrotic layers which require consecutive sharp debridement for at least two times (of the same ulcer)
• Minimal ulcer area of 1 cm2
• Leg ulcer has to enter into one of the following well defined aetiologies: venous, mixed venous-arterial, arterial, hypertensive ischemic leg ulcer (Martorell), vasculitic, ecthyma (covering >90% of all observed leg ulcers)
• Informed consent as documented by signature and being able to follow the study protocol (cognition)
• Proficiency in German, oral and written information

Exclusion Criteria:

• Women who are pregnant or breastfeeding (Women of childbearing potential need to perform a pregnancy test (urine test) within 24 hours prior to the study intervention and need at least one simple acceptable contraceptive method)
• Participants with hypersensitivity or allergy to lidocaine, prilocaine, tetracaine or auxiliary supplies contained in either EMLA® 5% cream or lidocaine-23%-tetracaine-7% gel.
• Participants with peripheral neuropathy (over 4/10 insensitive points with Semmes monofilament) are excluded due to disturbed pain perception, which could potentially influence the results.
• Participants that were previously included in this clinical trial
• Participants with a total wound area larger than 200 cm2