Clinical Comparative Analysis of Vertical Versus Transverse Skin Island Designs in Free Flaps Based on the Superficial Palmar Branch of the Radial Artery (SUPBRA).

Abstract

The superficial palmar branch of the radial artery (SUPBRA) flap provides glabrous, sensate, and pliable skin, making it a valuable option for digital reconstruction. The flap's skin island can be oriented either vertically or transversely; however, no prior study has compared these designs. This study presents the first clinical comparison of these two orientations, highlighting their anatomical and functional differences. Between 2018 and 2022, 29 patients underwent free SUPBRA flap reconstruction. Fourteen received vertical skin islands (vSupbra) and 15 received transverse designs (tSupbra). Flap anatomy, surgical parameters, sensory recovery, joint mobility, and donor-site aesthetics were evaluated using standard clinical and statistical methods. The average skin island size was 9.0 ± 2.1 cm² for vSupbra and 10.2 ± 2.4 cm² for tSupbra. The vSupbra flap had a significantly longer pedicle (2.0 ± 0.6 vs. 1.6 ± 0.4 cm, p = 0.0385), whereas the tSupbra flap had thinner skin (2.0 ± 0.5 vs. 3.4 ± 0.8 mm, p = 0.0043). Three complications occurred in each group, with no total flap loss. Functional outcomes showed better active range of motion (93.1° ± 2.4° vs. 80.4° ± 1.8°, p = 0.0139) and donor site aesthetics (VAS 8.4 ± 0.6 vs. 6.7 ± 0.7, p = 0.0030) in the vSupbra group. Sensory recovery did not differ significantly between groups (S2PD 5.7 ± 0.8 vs. 6.1 ± 0.9 mm, p = 0.6987). The vSupbra flap provides glabrous, adherent skin suitable for volar defects, while the tSupbra flap is more pliable and favorable for dorsal and articular reconstructions. Flap design should be tailored to the defect's anatomical and functional requirements. Flap selection should therefore be based on the anatomical and functional requirements of the defect. Previous literature has not described that the SUPBRA flap can be designed in two distinct orientations-vertical and transverse. This study is the first to demonstrate that these two skin island designs have different anatomical characteristics that provide distinct reconstructive advantages and limitations, guiding flap selection according to defect requirements.