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

Abstract

Background: 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. Methods: 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. Results: 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. Conclusions: 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.

Thin and superthin perforator flap elevation based on preoperative planning with ultrahigh-frequency ultrasound

“…UHF-US allows the visualization of microanatomical structures to the level of 30 μm, providing more detailed information regarding microvascular structures and subcutaneous anatomy than high-frequency US. A perforator can be followed to its entry point into the dermis and beyond, as previously reported [14,15].…”

“…This may be due to the relative lack of microanatomical knowledge regarding these flaps. In recent years, an increased number of research studies have been published to broaden knowledge of the subcutaneous and microvascular anatomy of thin and pure skin perforator flaps [6,7,[12][13][14][15].…”

“…Traditional perforator flaps cannot always fulfill reconstructive needs when the main goal is resurfacing, rather than filling space or creating volume. To overcome this limitation, thin flaps are becoming increasingly popular [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

Role of Ultrahigh Frequency Ultrasound in Evaluating Experimental Flaps

“…13 Recently, it's role in evaluating flap circulation at a capillary level has been brought forward in clinical studies. [14][15][16] Being able to visualize the microvascular anatomy of flaps is becoming now more important than ever given that more flaps are based on small perforator branches on which conventional ultrasound has limited use. Ultrahigh frequency ultrasound can be used to delineate intradermal plexus 16 and small perforator skin flaps with thickness less than 20 mm.…”

“…[14][15][16] Being able to visualize the microvascular anatomy of flaps is becoming now more important than ever given that more flaps are based on small perforator branches on which conventional ultrasound has limited use. Ultrahigh frequency ultrasound can be used to delineate intradermal plexus 16 and small perforator skin flaps with thickness less than 20 mm. 14,15 Prevention of flap necrosis has been a subject of experimental research since 1965 [17][18][19] (earliest reports in current literature).…”