LAUSR

Background: Human fingertips can regenerate functionally and cosmetically excellent skin and soft tissues. Physiological conditions suppress scar formation and are thus a prerequisite for regenerative healing. Self-adhesive film dressings can provide such favorable conditions. The semi-occlusive treatment is superior to surgery. However, standard dressings leak malodorous wound fluid eventually until the wound is dry. Therefore, we developed and tested a silicone finger cap that forms a mechanically protected, wet chamber around the injury. Its puncturable reservoir allows access to the wound fluid for diagnostic and research purposes and the delivery of pro-regenerative drugs in the future. Methods: Patients >2 years with full-thickness fingertip injuries unsuitable for simple primary closure were randomized to start treatment with either the film dressing or the silicone finger cap. After 2 weeks, we changed to the other treatment. Patients’ choice on the preferred treatment after 4 weeks was the primary outcome parameter. Additionally, we monitored adverse events, unplanned visits, tissue gain, functionality, cosmetic outcome, and quality of life. Results: We randomized 11 patients 2 to 72 years to each group. Eighteen to 20 (90%, intention-to-treat) patients preferred the finger cap. All patients were satisfied with the cosmetic outcome, 88.9% had no disturbing sensibility changes, and 73.7% could report no distortion in the finger’s daily use. Epithelialization took between 5 weeks for Allen II and up to 9 weeks in Allen IV injuries. There were 19 device-related adverse events under film dressing and 13 under the finger cap. There were neither severe adverse device effects nor unexpected severe adverse device effects. Conclusion: Employing the summative or synthetic primary endpoint "patient decision for one or the other procedure," our pseudocross-over-designed RCT succeeded in statistically significantly demonstrating the superiority of the silicone finger cap over conventional film therapy. The finger cap was safe and effective, reaching excellent results on all treated injuries without any need for disinfection, antibiotics, shortening of protruding bones, or treatment of hypergranulations. Distal to the tendon insertions, we did not see any limitations regarding injury mechanism, amputation plane, or patients' age.