Challenging Autologous Breast Reconstruction in Low BMI Patients with Profunda Artery Perforator (PAP) Flap: Impact of Skin Island Design on Complication Rates and Long-Term Aesthetic Outcomes

<b>Background:</b> The Profunda Artery Perforator (PAP) flap is a viable alternative to the Deep Inferior Epigastric Perforator (DIEP) flap, particularly for patients with low BMI and therefore insufficient abdominal tissue. To reduce the high complication rate, especially in our low BMI patient population, we have adapted the use of the vertical skin island design. This study compares complication rates and long-term outcomes of vertical versus horizontal skin island designs in PAP flap breast reconstruction. <b>Methods:</b> This prospective, single-center study included 20 patients who underwent PAP flap breast reconstruction. Quality of life and scar quality were assessed using the BREAST-Q and POSAS questionnaires. Additionally, the cosmetic outcomes were analyzed by four plastic surgeons. <b>Results:</b> Mean BMI in the vertical group was 23.9 kg/m² and 22.7 kg/m² in the horizontal group. Mean flap weight was 326 g for the vertical group and 355 g for the horizontal group. Fewer complications were observed at the donor site in the vertical group (Clavien-Dindo Classification 3b at donor site: <i>p</i> = 0.25). The BREAST-Q evaluation revealed significantly better results regarding the psycho-social well-being (<i>p</i> = 0.04) in patients with the horizontalskin island design. Scar evaluation using the POSAS revealed that the scar was perceived as thinner (<i>p</i> = 0.02), less pigmented (<i>p</i> = 0.03), and showed less relief (<i>p</i> = 0.02) in the vertical group. No significant difference was observed in the overall scar assessment by observers (<i>p</i> = 0.46). The aesthetic analysis by plastic surgeons showed significantly better results in the horizontal group. <b>Conclusions:</b> The vertical skin island design in PAP flap breast reconstruction was associated with lower complication rates and better scar quality compared to the horizontal design. Surgeons, however, rated the overall aesthetic outcome of the vertical design less favorably. These findings highlight the importance of balancing donor site morbidity with overall aesthetic results.