Assessing Possible Improvements to Cosmetic and Functional Outcomes of Penile Split Thickness Skin Grafting With Autologous Fat Graft

The investigators seek to study a novel adipose-based therapeutic strategy to improve cosmetic and function outcomes at the time of penile split-thickness skin graft (STSG) application during penile reconstruction. This entails a therapeutic repurposing of commonly utilized fat and skin grafting protocols to provide a fat-first reconstruction to address each of these limitations in one simple, economical, and widely accessible treatment for point-of-care penile reconstruction. Autologous adipose tissue is ideal as an adjunct to penile split-thickness skin grafting because it: 1) provides immediate, biologic soft tissue coverage with minimal to no donor site burden; 2) remains viable in poorly vascularized wound beds and can be placed as a biologic dressing without specialized microsurgical care; 3) enhances angiogenesis to mitigate risk of infection of deeper structures; 4) mitigates adhesions to underlying structures; and 5) can be used as immediate platform for rapid restoration of cutaneous integrity. By leveraging these techniques, the investigators seek to provide a safe, effective, and available option to augment standard-of-care reconstruction techniques.

Multiple conditions can lead to a need for penile reconstruction. Penile trauma, including burns, penetrating injury, blast injury, and friction injury can irreversibly damage penile skin, leading to a need to resurface the shaft and/or glans of the penis with local tissue flaps or autologous grafts. Infectious processes, most notably Fournier's gangrene, can also lead to loss of penile skin. Finally, adult-acquired buried penis (AABP) disease, a condition wherein the penis becomes trapped by adjacent soft tissues leading to chronic inflammation and loss of penile epithelial integrity, can require surgical excision of penile skin as part of a multicomponent repair. In all of these cases, STSG of the penile shaft is considered standard of care if local flaps, such as scrotal flaps, are not available for reconstruction due to overlapping disease processes. STSGs are commonly utilized to allow for rapid, definitive closure and restoration of the integument.

While STSG graft take on the penis following these processes is successful >95% of the time with restoration of urinary outcomes, patients who have undergone the procedure typically report dissatisfaction with the cosmetic appearance of their penile skin. This is due to adhesion of the STSG to the fixed Buck's deep fascia of the penis, which occurs due to the loss of the mobile Dartos fascia during the time of initial insult/injury. The combination of adhesion and graft contracture/fibrosis can lead to a "plasticky" feeling of the penile skin, which is especially bothersome given the expansile nature of the deep cavernosal bodies during sexual arousal. While current sexual outcomes in patients undergoing penile reconstruction are superior to patients who do not undergo reconstruction, there exists significant room for improvement. There currently exist no off-the-shelf products with proven efficacy in improving outcomes.

Adipose tissue is a prime candidate for this application due to its autologous origin, ease of procurement with minimal-to-no additional donor site morbidity, and abundant availability in patients, alongside its unique reconstructive and regenerative capacities. The use of autologous adipose in delayed tissue reconstruction is well established. However, the full therapeutic potential of adipose tissue remains underexploited. Fat grafting provides immediate soft tissue bulk, enhances angiogenesis, is both immunomodulatory and enhances immunologic homing, and supplies mesenchymal cells for soft tissue healing. Fat grafting is viable in hostile recipient beds including infected/contaminated and poorly vascularized wounds such as the diabetic foot ulcer, irradiated skin, and burn scars.

Grafting of autologous fat tissue is a minimally invasive surgical technique that starts with the harvest of small particles (2-5 mm) of fat tissue from the abdomen or using liposuction. Sometimes, fat graft can be harvested from tissue that is removed for other reasons. This technique utilizes incisions smaller than 5 mm in length and rapid intraoperative processing allowing for immediate transplantation of a patient's own tissue in a single operative procedure. Autologous fat can also be obtained from adipose tissue removed intraoperatively, which is a standard component to AABP repair, and processed intraoperatively for immediate use. This follows a standard fat grafting preparation protocol currently being used for standard of care cases.