Musculocutaneous Latissimus Dorsi Free Flap Phalloplasty Model in Pigs - Learning Tool for Genito-Urinary Reconstructive Surgeons

The number of transgender patients with dysphoria requiring phalloplasties has increased in the past decades, generating a shortage of skilled surgeons who can perform this very demanding procedure. We offer an experimental model for harvesting a musculocutaneous latissimus dorsi (MLD) flap in pigs, which is transferred to the inguinal region and anastomosed to the recipient vessels and nerve, completing the phalloplasty procedure. Four common-breed female pigs, weighing 35-42 kg, were used as a training model to standardize the harvesting procedure. A MLD free flap of 15 × 15 cm with 12 × 4 cm calf of muscle is designed. Dissection of the flap is performed, preserving the thoracodorsal pedicle. After the flap is lifted, it is rolled into a cylinder to obtain the desired shape of the penile shaft and the glans reconstruction was performed. The flap is transferred to inguinal region and microvascular anastomosis with recipient vessels (caudal superficial epigastric vessels) and nerves (anterior branch of the obturator nerve) was performed. All four flaps were viable before the main pedicle was sectioned, with no signs of damage to either thoracodorsal artery or vein. Muscle contraction was present after harvesting and detaching of the neurovascular bundle, demonstrating the contraction capability of the neophallus. After the transfer to the inguinal region, flap perfusion was excellent in all 4 cases, with no signs of ischemia or congestion. Flap perfusion was monitored via capillary refill as well as Laser-Doppler line scanner and thermal imaging, with no signs of ischemia. Currently, there are three main surgical approaches to phalloplasties, involving either free radial forearm, anterolateral thigh or MLD flaps. The proposed experimental model in pigs can be a useful learning tool to reconstructive surgeons, representing a detailed simulation of the human procedure. The authors declare no conflict of interest.