Application of a strip design to monitor the viability of buried radial forearm free flap in East Asians: A case series study

Objectives: The objectives of this study were to evaluate the reliability of a strip design as a monitoring flap in buried flap and to investigate whether strip design of radial forearm free flap (RFFF) could affect donor site morbidity in East Asian.

Methods: Patients with externalized flap in buried RFFF were consecutively included in this study. For cases with mucosal defect repair, a skin strip with a 1.5 cm width was proximally positioned to the primary flap along with the pedicle. Compared to a mucosal defect, a skin strip was distally positioned overlying the pedicle (near the wrist) when the flap was used for reinforcing the facial contour, reconstructing sacrificed facial nerve, or reanimating facial expression. The externalized flap formation was performed after completion of anastomoses of vessels. Monitoring results of flap failure using an externalized monitoring flap and additional morbidity of donor site were evaluated.

Results: Nine patients were included in this study. Although there were two cases of pharyngeal fistula due to mucosal necrosis of resection margin, transferred RFFF was viable in all cases. The externalized flap provided reliable monitoring for the buried RFFF without a case of necrosis even in two cases with a partial detachment of septocutaneous branches between the radial artery and the designed skin strip. There was no false - positive case. Therefore, the sensitivity and positive predictive value of the externalized monitoring flap were 100%. All defects of radial forearm caused by skin strip harvest were also primarily closed without an additional skin graft.

Conclusion: A strip design for externalized monitoring flap in RFFF can facilitate an easier creation of externalized monitoring flap in cases with buried RFFF without additional morbidity at the donor site compared to a conventional techniques.