Nomenclature of Thin and Super-Thin Flaps—Comment on: Outcomes of Subfascial, Suprafascial, and Super-Thin Anterolateral Thigh Flaps: Tailoring Thickness without Added Morbidity

We read with great interest the article by Diamond et al[1] comparing the morbidity of subfascial, suprafascial, and super-thin (periscarpal) anterolateral thigh (ALT) flaps. They used ALT flaps for head and neck and extremity reconstruction with great success opting for different levels of dissection depending on the defect. In their study, no significant recipient-site morbidity was found between groups, although partial loss was more common in periscarpal group compared with the suprafascial group (16.7 vs. 0%, p = 0.11). Based on our experience, we agree that there is little difference in morbidity related to elevation level. While the majority of publications on thinning flaps stem from Asia, the study authors present much welcome data on Western free flap patients with larger body mass indexes and thicker flaps.

In this letter, our primary intention is to emphasize the confusion regarding nomenclature of thin flaps between Asian and Western studies. The present study is demonstrative of this confusion, as periscarpal flaps were regarded as super-thin flaps. Free periscarpal flaps are usually called “thin flaps” rather than “super-thin” in Asian studies.[2] These flaps are thinner than suprafacial or subfascial counterparts with no added morbidity.[1] [2] However, periscarpal flaps in obese female patients are generally more than 1 cm in authors' experience, making it difficult to call “super-thin.” For dorsal hand/foot resurfacing, we prefer other options such as thin superficial circumflex iliac artery perforator or subdermal flaps.

Although the concept of “super-thin” pedicled flaps dates back to the 1960s, “super-thin” flaps were first proposed in the 1990s.[3] According to Asian studies, super-thin flaps are based on subdermal vasculature and the flap elevation level is closer to dermis with little to no attached subcutis, yielding a flap thickness around 2 to 3 mm.[3] [4] [5] Narushima et al[4] classified thinned flaps, from thinnest to thickest: split-thickness skin flap, full-thickness skin flap (pure skin perforator flap), super-thin flap (subdermal vascular network flap), and thin flap (above the superficial fascia layer).

Thus, in the study by Diamond et al,[1] it may be misunderstood that subdermal network flaps (super-thin flaps) are as safe as suprafascial or subfascial flaps. However, free super-thin flaps or subdermal flaps have yet to be compared with thin flaps. Flap type, gender, obesity, and ethnicity may significantly influence flap thickness. As the fat included in subdermal flaps is minimal to none, the thickness of these flaps is not related to the aforementioned variables. For this reason, we agree with the Asian literature. Additionally, we prefer calling flaps “super-thin” if ≤4 mm regardless of elevation level. Regardless, there is no consensus concerning the nomenclature of super-thin flaps, and may cause confusion in the literature.

We congratulate the authors on their contribution to the body of literature on thin flaps especially in that it reports on larger Western patients. Their terminology, however, does highlight a growing need for standardized nomenclature in reference to thin flaps. Similar to the consensus reached for perforator and chimeric flap nomenclature, authors from both the East and West should agree upon a terminology to thin flaps based on anatomy.

• References

• 1 Diamond S, Seth AK, Chattha AS, Iorio ML. Outcomes of subfascial, suprafascial, and super-thin anterolateral thigh flaps: tailoring thickness without added morbidity. J Reconstr Microsurg 2018; 34 (03) 176-184
• 2 Hong JP, Choi DH, Suh H. , et al. A new plane of elevation: the superficial fascial plane for perforator flap elevation. J Reconstr Microsurg 2014; 30 (07) 491-496
• 3 Sun YH. [Blood circulation of the “super-thin” skin flap with preserved subdermal vascular network and its clinical application]. Zhonghua Zheng Xing Shao Shang Wai Ke Za Zhi 1991; 7 (01) 8-10 , 73
• 4 Narushima M, Yamasoba T, Iida T. , et al. Pure skin perforator flaps: the anatomical vascularity of the superthin flap. Plast Reconstr Surg 2018; 142 (03) 351e-360e
• 5 Kimura N, Saitoh M, Hasumi T, Sumiya N, Itoh Y. Clinical application and refinement of the microdissected thin groin flap transfer operation. J Plast Reconstr Aesthet Surg 2009; 62 (11) 1510-1516