The pudendal thigh flap for vaginal reconstruction: optimising flap survival

The pudendal thigh fasciocutaneous (PTF) flap is a useful flap in perineal reconstruction, that is reliable when small but is traditionally unreliable when large flaps are raised. Large flaps in particular, are associated with an increased incidence of apical necrosis. Thorough descriptions of the vascular anatomy of this flap have been lacking from the literature, with the current study evaluating this anatomy, aiming to provide the anatomical basis for vascular problems and for techniques to maximise its survival.

Five unembalmed human cadaveric pelvis specimens were studied. Lead oxide injectant enabled radiographic and dissection analysis of the arterial anatomy of the integument of the perineum.

A consistent pattern of vascular supply was found in all specimens. 1: the blood supply to the pelvic floor was supplied sequentially by the posterior labial/scrotal arteries, cutaneous branches from the anterior branch of the obturator artery, and branches from the external pudendal arteries. 2: these vessels ran close to the midline, medial to the PTF flap. 3: the posterior labial/scrotal arteries were deep to the Colles' fascia and the branches from the obturator artery and external pudendal arteries were located superficial to the Colles' fascia.

This study has demonstrated that the PTF flap is a three vascular territory flap and that the pedicle is situated close to the midline. This may explain why regions of the PTF flap may have a potentially precarious blood supply, and suggests that the PTF flap should be designed more medially. Given the third territory of supply to the apex of the flap, a delay procedure may help to avoid flap necrosis.