Local Flaps For Wounds: Rules Of Rotation And Advancement

Noting that advancement and rotation flaps offer key advantages over skin grafting, this author discusses factors and considerations in choosing a flap technique to facilitate wound closure.

Soft tissue reconstruction in the surgical management of lower extremity wounds can pose a challenge to surgeons involved with these high-risk patient populations. The combination of local tissue advancement and rotational flaps is one of the many modalities and techniques available to the surgeon to provide soft tissue coverage over a defect. Some clinicians have a tendency to shy away from these types of procedures due to a sense of complexity. However, in truth, these techniques are not terribly complicated once one has a sense of the basic principles and can apply these principles in geometric patterns on the foot.

Prior to a discussion regarding the specific details of rotational and advancement flaps, it is important to develop a clear understanding of the terminology as surgeons have described in the literature and in clinical practice. In 1920, Gillies wrote that “a graft is a piece of detached skin which is dead when you put it on and which may come to life later. A flap is a partly attached piece of skin which is alive when you put it on and may die later.”^1,2 While seemingly coming across as esoteric, Gillies provides great insight into the fundamental differences between these similar but separate surgical modalities. Both are useful in lower extremity soft tissue reconstruction and surgeons commonly utilize both modalities.

However, I would suggest that advancement and rotation flaps demonstrate several key advantages over skin grafting.^3,4 The final appearance of a wound closed with a local tissue flap is often superior to that of a free graft, and the quality of the skin that covers the defect is far better because it is comparable to the neighboring tissue from which it was obtained. While a secondary donor site defect is necessary for most of these local tissue flaps, the nature of the geometry of the flap allows for closure of this donor site, thus negating the need for a distant secondary donor site and the potential comorbidity associated with such sites.^5,6

Pertinent Principles With Incision Planning And Local Flaps
As with any surgery, the surgeon must have a fundamental understanding of the surgical principles and anatomy of the areas in which he or she will be operating, and cutaneous surgery is no different. A lack of understanding of these principles and the pertinent anatomical features can lead to irreversible harm to the patient. A thorough understanding of the cutaneous structures and their underlying neurovascular elements is necessary to perform skin-related procedures such as local tissue rotation and advancement flaps.⁷

When considering local tissue flaps, some key considerations are the concepts of contour lines and lines of minimal movement. One often sees contour lines around prominent structures — the first and fifth metatarsals for example — and surgeons can use these contour lines to camouflage and reduce the prominence of surgical scars. This is most effective when one applies the concept of lines of minimal movement and relaxed skin tension lines to provide for soft tissue coverage over the defect. Lines of minimal movement and relaxed skin tension lines are similar in concept although they vary slightly. One should consider both when assessing the wound to determine the most effective flap geometry.^8,9 When there are lines of minimal movement, the clinician can find the greatest movement in orientations perpendicular to the lines of minimal movement.

Relaxed skin tension lines are associated with creases and natural areas of flexion and extension that form as a consequence of the underlying deep structures. Skin demonstrates the greatest ability to be mobilized to relieve tension in a direction that is perpendicular to the relaxed skin tension lines. This line which is perpendicular to the relaxed skin tension lines is known as the line of maximum extensibility.⁹ It is important to attempt to orient the incisions along these lines for overall decreased tension along the surgical site. Clinicians have shown that doing so reduces the degree of scar formation and this is of particular concern in weightbearing areas.¹⁰

Additionally it is helpful to consider that one can divide the foot into functional units. For example, the surgeon can divide the forefoot into dorsal and plantar surfaces. Generally speaking, it is best to try to contain local tissue advancement and rotational flaps within functional units. For example, it would be best to manage a dorsal foot defect with a dorsal flap. Maintaining flaps within functional units reduces the potential for vascular compromise by keeping the flaps within angiosome boundaries.^11,12 Unlike named artery flaps, local tissue flaps are perfused by unnamed cutaneous perforating arteries.^13,14 These perforators are small and fragile. That is why authors recommend minimal dissection and undermining when preparing a local tissue flap, and recommend using atraumatic technique when advancing or rotating these flaps into position.¹⁴

These basic principles can guide the surgeon with incision planning and assessment of flap geometry. A failure to plan adequately for an incision can ultimately lead to increased scar formation, which can be both painful and unsightly.

Keys To Choosing An Appropriate Flap Technique
There are many types of advancement, rotation and transposition flaps. Many flaps utilized in lower extremity soft tissue reconstruction are actually a hybrid combination of both rotation and advancement flaps, and these are sometimes called transposition flaps.^15-17 The choice of flap largely depends upon the familiarity of the surgeon, the nature of the defect, its size and anatomic location.

Appropriate preoperative evaluation is necessary because rarely do flaps provide more motion than one can observe during the preoperative evaluation. There are numerous techniques available to the surgeon to attempt to recreate the relaxed skin tension lines and determine the line of maximum extensibility for incision planning. With appropriate preoperative planning, local tissue flaps behave quite predictably. A failure of planning can lead toward ischemia, hematoma and flap failure.

Essential Insights On Utilizing Simple Local Flaps
Simple advancement flaps are among the most common and most easily visualized type of local flaps. When utilizing this technique, the surgeon resects the lesion or wound, and extends the two incisions away from the ovoid defect (ideally perpendicular to the relaxed skin tension lines and parallel to the line of maximum extensibility in this anatomic area).¹⁸ One would subsequently mobilize and undermine the tissue as necessary to advance the leading edge of the flap forward across the top of the defect, thus covering the defect.¹⁹ Surgeons should perform this technique with minimal tension to provide the greatest likelihood for success. This can occasionally produce dog ears along the proximal portions of the flap but one can excise these without incident when necessary. This type of technique is useful on smaller defects, commonly those that are 1 cm or smaller in diameter.

As wound size increases and depending on the anatomic location of the wound, the surgeons can employ modifications of the simple advancement flap, such as the pantographic expansion flap or double advancement flap, to achieve soft tissue closure.

A pantographic expansion flap is simply a modification of the simple advancement flap with one orienting the base of the flap slightly wider than the distal end to allow for mobilization of the tissue without dog ear formation.^20,21 While effective, this flap can compromise vascularity in the tissue and is not commonly recommended. A double advancement flap is essentially two converging, simple advancement flaps that a surgeon can utilize to provide soft tissue coverage across defects that are of a larger diameter than one can cover without tension via one flap. In all cases, the incision placement is ideally parallel to the line of maximum extensibility. This provides the greatest chance of flap survival.

Simple rotation flaps are a variation on that theme. With an advancement flap, all of the tissue comes from the direct movement of the flap toward and across the defect.²¹ Conversely, with rotation flaps, one has several options for tissue mobilization that allow for defect closure because rotation occurs around a pivot point. Consequently, there is primary motion (like in an advancement flap) but also secondary motion that occurs. One uses the classic rotation flap to close a triangular defect where, with wound closure, the greatest line of tension extends from the pivot point toward the area of the original defect. Accordingly, when planning a rotation flap, it is helpful to visualize the orientation of the pivot point in relation to the defect to assess placement in line with the line of maximum extensibility. Authors have described many variations of the rotation flap in the literature and all are essential variations on the aforementioned theme. Generally, these vary based upon the orientation of the axis of incision.

A drawback for the classic rotational flap is the need for a triangular defect. Lower extremity wounds are commonly circular or ovoid in nature. Accordingly, in order to create the triangular defect necessary for the flap to rotate, one would have to enlarge the defect. Considering this, surgeons have described the use of a single-lobed flap to allow for wound closure without having to significantly enlarge the defect.
Single-lobe rotation flaps are, in reality, a combination of a rotation and an advancement flap in which both the defect and the flap one utilizes to close the defect are vaguely circular or ovoid. The surgeon can place the flap anywhere along the margin of the defect to allow for anatomic and line of maximum extensibility considerations. The angle with which one would order the flap to the defect depends on the shape of the wound. With more circular defects, the flap is oriented in such a way that excision of the defect forms a right angle between the defect and the start of the flap. As the wound becomes more elongated, the angle between the orientation of the resected defect and the margin of the flap becomes smaller, commonly around 60 degrees.²²

The use of bilobe or double-lobed rotation flaps involves the mobilization of two flaps that share a common pedicle and the surgeon generally orients these flaps at approximately 90 degrees to one another.²³ As one might expect, this flap geometry allows the surgeon to provide greater tissue coverage with more tissue moved over a longer distance.²⁴ With the use of two flaps, there are two donor sites as well. The first flap rotates into the original defect and the second flap rotates into the primary donor site created by the first flap. One then closes the secondary defect in primary fashion with as minimal tension as possible.²⁵

A Closer Look At Transposition Flaps
Transposition flaps, as I described previously, are essentially hybrid combinations of rotation and advancement flaps to provide soft tissue coverage across a defect.¹⁷ Commonly, surgeons use these flaps to transfer tension away from the closure of a primary defect and redirect that tension along the secondary defect repair site. Like rotation flaps, there is rotation of tissue around a primary pivot point.

However, there is often a secondary donor site that one cannot close primarily. In these instances, the surgeon often closes the donor site defect with the placement of a split thickness skin graft (STSG). Authors have introduced various geometric designs in the literature to attempt to reduce this need for STSG of donor site defects. Perhaps the most commonly noted flaps in this scenario are the rhombic flaps. These transposition flaps utilize a flap that is oriented at 90 degrees to the defect but these angles can vary anywhere from 30 to 120 degrees. To utilize this type of geometric arrangement, one needs to ensure adequate donor site tissue to provide for closure of the primary defect as well as the donor site defect, either primarily or via STSG.¹³

In Conclusion
The use of advancement and rotation flaps in lower extremity soft tissue reconstruction provides the surgeon with a great many options for soft tissue closure, especially along the plantar aspect of the foot. When one utilizes these techniques correctly, they can be important additions to the surgeon’s armamentarium. As with all surgical procedures and perhaps more so than most, specific and deliberate preoperative planning is essential for successful outcomes.

A thorough understanding of the cutaneous and subcutaneous anatomy, and how these anatomical features contribute to the capacity for tissue laxity is necessary for appropriate design and utilization of advancement and rotation flaps. Not every flap works for every anatomic location and wound shape. Accordingly, the surgeon must be able to visualize the anticipated flap orientation as well as the subsequent donor site defect to adequately assess which flap geometry would work best.

Dr. Fitzgerald is a Clinical Assistant Professor of Surgery at the University of South Carolina School of Medicine. He is a founding member of the Greenville Health System Center for Amputation Prevention. Dr. Fitzgerald is a Fellow of the American College of Foot and Ankle Surgeons. He is board certified in reconstructive rearfoot and ankle surgery as well as foot surgery by the American Board of Foot and Ankle Surgery.

References

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2.     Gillies HD. Plastic surgery of the face based on selected cases of war injuries of the face including burns (with original illustrations). JAMA. 1920:75(25);1738.
3.     Robbins TH. Single stage local flap repair. Med J Aust. 1979;1(11):523.
4.     Simmonds WL. Local skin-flap repair of surgical defects of the upper lip in excisions of lesions. J Dermatol Surg. 1975;1(2):33-6.
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12.     Varela C, Acin F, de Haro J, et al. The role of foot collateral vessels on ulcer healing and limb salvage after successful endovascular and surgical distal procedures according to an angiosome model. Vasc Endovascular Surg. 2010;44(8):654-60.
13.     Jakubietz RG, Jakubietz MG, Gruenert JG, Kloss DF. The 180-degree perforator-based propeller flap for soft tissue coverage of the distal, lower extremity: a new method to achieve reliable coverage of the distal lower extremity with a local, fasciocutaneous perforator flap. Ann Plast Surg. 2007;59(6):667-71.
14.     Ding ZQ, Kang LQ, Zhai WL. [Local plantar rotatory flap for repairing of soft tissue defect of heel]. Zhongguo Xiu Fu Chong Jian Wai Ke Za Zhi. 1999;13(6): 337-9.
15.     Yazar M, Kurt Yazar S, Celet Ozen B, et al. Cosmetic closure of pilonidal sinus defects with bilateral transpositional adipofascial flaps. J Plast Surg Hand Surg. 2013;47(4):292-6.
16.     Park EY, Elliott ED, Giacopelli A, Granoff DP, Salm RJ. The use of transpositional skin flaps in closing plantar defects: a case report. J Foot Ankle Surg. 1997;36(4):315-21; discussion 329.
17.     Congdon GC, Altman MI, Aldridge J. A comparison of transpositional neurovascular skin flaps for reconstruction of diabetic heel ulcerations. J Foot Surg. 1988;27(2):127-9.
18.     Cecchi R, Bartoli L, Brunetti L, Troiano G. Repair of a large lateral foot defect with a combination of keystone island flap and V-Y plasty. Eur J Dermatol. 2015;25(6):618-9.
19.     Onishi K, Maruyama Y. The dorsal metatarsal V-Y advancement flap for dorsal foot reconstruction. Br J Plast Surg. 1996;49(3):170-3.
20.     Masaki F, Shuhei Y, Riko K. A technique to avoid a dog-ear deformity on the buttock using a “pigeon head” modification of the rotation flap. Wounds. 2007;19(3):69-72.
21.     Beidas OE, Tan BK, Petersen JD. The rotational advancement of medial plantar flap for coverage of foot defect: a case report. Microsurgery. 2012;32(4):322-5.
22.     Bakos LH. Transpositional flap procedures (lipswitch): report of a case. W V Dent J. 1981;55(4):14-5.
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24.     Sahin C, Ergun O, Kulahci Y, et al. Bilobe flap for web reconstruction in adult syndactyly release: a new technique which can avoid the use of skin graft. Plast Reconstr Surg. 2015;136(4 Suppl):28-9.
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For further reading, see “A Guide To Using Bilobed Flaps In Lower Extremity Surgery” in the May 2013 issue of Podiatry Today or “Can Great Toe Pedicle Flaps Have An Impact For Complicated DFUs?” in the August 2012 issue.