Visualization of the "Intradermal Plexus" Using Ultrasonography in the Dermis Flap: A Step beyond Perforator Flaps

Free flaps have evolved from musculocutaneous flaps to perforator-based cutaneous flaps. The subdermal plexus is now thought to play a significant role in skin paddle perfusion. We propose a new concept, the "intradermal plexus," allowing survival of dermis flaps, according to our study.

A dermis flap was used in 6 cases to reconstruct small defects. The superficial branch of the superficial circumflex iliac artery was traced distally using an ultrasound device with a 70-MHz linear array transducer until the artery's branch entered the dermis. The location of the dermis entry site was marked and the vessels running inside the dermis were observed and video-recorded. A flap was elevated above the superficial fascia, and the adipose tissue was removed using scissors after confirmation of the vessels' dermis entry point.

The use of 70-MHz ultrasonography permitted observation in all patients of small arteries entering the dermis layer. The artery was observed to give off branches after entering the dermis, in effect constituting an "intradermal plexus." Small veins entering the dermis were similarly visualized using 70 MHz ultrasonography. All flaps survived completely.

Small arteries and veins entering and running inside the dermis were visualized for the first time with 70 MHz real-time ultrasonography. Knowledge of the existence of this "intradermal plexus" made it possible to discard nearly all subdermal adipose tissue quickly and safely, without resorting to the elaborate measures described in previous reports.