The purpose of this study is to determine whether the use of running subcuticular suture versus running horizontal mattress suture for the repair of cutaneous linear wounds on the trunk and extremities affects aesthetic outcomes. The study team will use a split wound model, where half of the wound is repaired with running subcuticular sutures and the other half is repaired with running horizontal mattress sutures. Three-months post-surgery, the scar will be evaluated via the patient observer scar assessment scale (POSAS), a validated scar instrument, as well as the trace-to-tape method, an objective outcome measure for linear postoperative scars. Any adverse events will also be recorded.

Sutures are the standard of care in repairing cutaneous wounds. The majority of surgical reconstructions following a Mohs micrographic surgery and standard surgical excisions require two layers of sutures: a deep (subcutaneous) layer and a superficial (cuticular) layer. Given the overall lack of evidence in the literature, the choice of suturing technique is largely dependent on the surgeon's preference.

This study aims to investigate whether the use of running subcuticular sutures, when compared to running horizontal mattress sutures, affects wound cosmesis on the trunk and extremities.

Both running subcuticular and horizontal mattress suture techniques have been favored by surgeons for differing reasons. With running subcuticular suture, epidermal puncture points are minimized. Thus, suture may be left in place for longer periods of time leading to improved wound healing and less risk of suture-track scars. A previous study by Alam et al found that running subcuticular suture had improved appearance as compared to running cuticular suture. In contrast, the horizontal mattress suture is useful to redistribution wound tension and evert wound edges, which is felt to improve aesthetic surgical outcomes as well. Moody et al showed that when compared to running cuticular suture, a running horizontal mattress suture led to a smoother and flatter scar.

However, while there have been studies comparing and finding superiority of both the subcuticular running suture and running horizontal mattress suture compared to the running cuticular suture, these two techniques (namely, subcuticular running and running horizontal mattress) have not been directly compared to each other. We hope that our study will provide new insight into this aspect of cutaneous surgery.

This is a single center, randomized, evaluator blind, split wound study.

After screening and informed consent, demographic data will be collected including date of birth, race, gender and medical record number.

The patient's wound will be labeled A if it is on the left or superior side of the investigator and B if it is on the right or inferior side. A predetermined, concealed randomization number will be obtained from the redcap randomization module, which will specify how side A is to be treated. Side B will be treated the opposite way as A. Side A will always be closed first. Prior to placement of the cutaneous sutures, both sides of the wound will be sutured together with a subcutaneous (bottom) layer of stitches, as is the standard of care. A digital image of the wound before and after the epidermal closure will be obtained; these may be used in scientific talks and/or for publication purposes. Treatment assignment, wound length, demographic data, and digital images will be recorded within the redcap database. Follow-up assessment will be scheduled for three months following the procedure, with a one-month window before or after that time if the patient cannot return at precisely three months.

At the follow-up visit, two blinded observers will record their scores independently using the POSAS instrument. The mean scar width will also be determined using the trace-to-tape method. If one half of the scar has more associated erythema, that will be recorded. The patient part of the instrument will be independently recorded. Digital images will then be obtained again, which may be used for scientific meeting presentation and/or publication purposes.

All patients scheduled for cutaneous surgical procedures with one of the study investigators at the UC Davis Dermatology Clinic will be screened for eligibility.

Inclusion Criteria:

• 18 years of age or older
• Able to give informed consent themselves
• Patient scheduled for cutaneous surgical procedure on the trunk or extremities with predicted primary closure
• Willing to return for follow up visit

Exclusion Criteria:

• Incarceration
• Under 18 years of age
• Pregnant Women
• Wounds with predicted closure length less than 3 cm