A Call for Clarity in TRAM/DIEP Zones

Sir: As we were preparing an article on the deep inferior epigastric perforator (DIEP) flap, we were confounded by the confusing nomenclature describing the zones of this and related flaps. We feel that an accurate and unambiguous restatement of these zones is long overdue. The muddle arose in 1983, when Scheflan and Dinner introduced the concept of perfusion zones of the pedicled transverse rectus abdominis musculocutaneous (TRAM) flap.1 Based on an impression from their early experience with the flap, they named the area overlying the pedicle “zone 1,” the contralateral-medial area “zone 2,” the ipsilateral-lateral area “zone 3,” and the contralateral-lateral area “zone 4.” Evidently, it soon became clear to them that their initial nomenclature did not reflect the true order of perfusion, and in their follow-up article from the same year they switched zones II and III,2 perhaps using roman numerals to distinguish the new system from the old. Although the use of roman numerals caught on, the new system did not, as the initial nomenclature had already been popularized. Numerous investigators have repeatedly validated the revised zones and have shown that they apply not only to the pedicled TRAM flap but also to the free TRAM and DIEP flaps. Our group showed that they also apply to the superficial inferior epigastric artery flap.3 Clearly, the initial nomenclature is misleading with regard to the perfusion of any of these flaps. However, misnomers die hard, and the old system remains in wide use. The terms “zone II” and “zone III,” if used without qualification, are therefore utterly ambiguous. Clarification is sometimes attempted with the term “Hartrampf zones,” which is indeed clear but denies eponymous credit to those who first described the zones and ignores the fact that the initial description is inaccurate; and if the term Hartrampf zones is used for the initial nomenclature, what should be used for the revised nomenclature—“Scheflan-Dinner zones”? However, those authors are associated with the initial nomenclature too. Rickard suggested that the zones be renamed according to Taylor's angiosome concept, but this would result in a cumbersome system of up to seven zones, and the same area would assume a different name depending on which source vessel was used.4 Shoaib and Marucci felt that zones II and III should both be called zone II, because both are adjacent to the axial angiosome, and zone IV should be called zone III, because it is one more angiosome away.5 However, their suggestion neglects the fact that zones II and III are clinically distinct. Furthermore, as numerals are also used to describe the zones of an abdominoplasty flap, they are inherently confusing in the context of abdominal territories and should be avoided altogether. To minimize ambiguity yet maintain simplicity, we propose the use of letters to specify the zones, using I and C (for ipsilateral and contralateral) and the subscripts M and L (for medial and lateral). Thus, the four zones would be (in order of perfusion) IM, IL, CM, and CL (Fig. 1), and would be applicable to any of the flaps using this tissue. Note that our system departs from previous ones in that it describes location rather than perfusion. No system can represent both without becoming unwieldy, and because the perfusion order has been so thoroughly proven and widely accepted as to be almost self-evident, we feel that location is the more useful descriptor.Fig. 1.: Our proposed zones, applicable to the pedicled TRAM, free TRAM, DIEP, and superficial inferior epigastric artery flaps.We hope that publication of our proposal in Plastic and Reconstructive Surgery will spur its use in the literature. The benefits will go both to students who learn about these flaps and to those who, like ourselves, write about them. Steven L. Henry, M.D. Ming-Huei Cheng, M.D., M.H.A. Department of Plastic and Reconstructive Surgery Chang Gung Memorial Hospital Taoyuan, Taiwan