In this article, I am presenting a variety of working models for closure of skin defects of different shapes along with their corresponding indications and mode of use. These working models can be enlarged or reduced in size using a regular copying machine in order to evaluate the best possibilities related to the position of the incision. The great advantage of this method is that the geometric results are always predictable. Furthermore, this method will improve the survival of the flaps and the cosmetic results. In summary, the surgeon can use a variety of skin incisions taking advantage of the minimal tension lines of the skin and also taking into consideration the anatomical characteristics of the region involved. In this article, I have used the minimal tension lines of the skin, because they are easy to demonstrate by simple measures, such as pinching of the skin in different directions. In addition, the surgeon can assess the mobility and the elasticity of the skin on an individual basis.
- skin defects closure
- soft tissue flaps
- pedicled skin flaps
- reciprocal incisions
- circular and semicircular incisions
- triangular incisions
- oval and elongated hexagonal incisions
- skin minimal tension lines
- relaxed skin tension lines
When excising large skin lesions, the ideal incision is a circular one, since most of the skin lesions are round, and because it provides an adequate margin of resection, and at the same time will avoid the removal of sound skin. The main problem with this approach is that the resultant circular defect may prove to be very difficult to close. To solve this problem, the surgeon can use different incisions that can be closed in a more expedite way and with better cosmetic results. Another alternative would be a split-thickness skin graft, which sometimes would not match the color or texture of the recipient area [1, 2, 3].
It is for these reasons that the surgeon has to use different methods such as using a rhombic or elliptical incision that leaves a long suture line and will waste more sound skin. In some cases, the circular incision can be transformed into a square incision, such as the Dufourmentel flap , or into a rhomboid defect, such as the Limberg flap , but both of them will generate loss of sound skin. The Limberg method for closure of a hexagonal defect uses three triangular flaps, but these flaps are rather small which may compromise their survival. Besides this, the resultant triangular suture line is not cosmetically acceptable.
2. Closure of circular skin defects
I designed three “reciprocal incisions” in 1981 aiming to close large circular defects  with minimal waste of sound skin and at the same time to avoid the formation of dog ears. The first one is the
For circular skin defects, two incisions were described, the
3. Closure of semicircular skin defects
For semicircular skin defects, two incisions were described, the
4. Closure of triangular skin defects
Most of times, skin lesions have a round shape; but in certain cases, the lesions could present themselves in a triangular shape. In the recent medical literature, there are few methods that can be used for closure of triangular skin defects such as the L-shaped flap for triangular skin defects of Sakai and Soeda  and the Mutaf triangular closure , or the triangular excision for small lesions of Filho and colleagues . The tracing of the first two incisions is rather complicated and the resultant flaps have a narrow base that could jeopardize their survival.
It is for these reasons that I published a “Simple method for closure of triangular skin defects”  in 2016. These incisions are easy to trace and to memorize, and more important, they are provided with wide base flaps. Furthermore, the resultant suture lines are away from the central area of the incision and the edges of the suture lines complies with the principle of reciprocity by which the edges of the skin end up even and without the formation of dog ears. In addition, these incisions have the advantage of producing a short suture line, as compared with the Sakai Soeda and the Mutaf incisions.
As a consequence, this simple method for closure of triangular skin defects could very useful for closure of large meningoceles or when resecting pilonidal sinuses or when removing triangular defects of the face. In the present article, these incisions have been slightly modified in order to produce a better suture line (Figures 8 and 9). Besides this, their tracing is easier to memorize, since the base of the triangles are always divided in half instead of dividing in quarters.
5. Closure of oval and elongated hexagonal skin defects
In some occasions, the skin defects take the configuration of an oval (Figure 10) or an elongated hexagon (Figure 11) which would require considerable extensions at their extremities that in some confined anatomical regions is not feasible. To solve this problem, I am presenting here two new paper models that are easy to trace and to memorize with the advantage of generating a short suture line and with practically no wastage of skin.
Any of the incisions described in this article can be selected to accommodate to the characteristics of a particular anatomical region. For instance, the
7. Mode of use
For practical purposes, a working model of bond paper can be made to evaluate the different possibilities according to the anatomy and the particular conditions of the skin surrounding the lesion. The working models included here can be enlarged or reduced in size by using a regular copying machine, in advance of the operation. They could be used on the spot to test the more convenient position according to the size of the lesion to be removed. The center portion of the selected model can be removed in order to estimate the resection margins and the proper orientation of the incision.
In this article, I am presenting a variety of working models for closure of skin defects of different shapes along with their corresponding indications and mode of use. These working models can be enlarged or reduced in size using a regular copying machine in order to evaluate the best possibilities related to the position of the incision. The great advantage of this method is that the geometrical results are always predictable. Furthermore, this method will improve the survival of the flaps and the cosmetic results.
In summary, the surgeon can use a variety of skin incisions taking advantage of the minimal tension lines of the skin and also taking into consideration the anatomical characteristics of the region involved. For this purpose, the paper models described here can be prepared in advance of the planed surgery to make sure that they adapt to a particular location and according to the elasticity and mobility of the surrounding skin.
Paul SP. Biodynamic excisional skin tension (BEST) lines: Revisiting Langer’s lines, skin biomechanics, current concepts in cutaneous surgery, and the (lack of) science behind skin lines used for surgical excisions. Journal of Dermatological Research. 2017; 2(1):77-87
Wilhelm BJ, Blackwell SJ, Phillips LG. Langer’s lines: To use or not to use. Plastic and Reconstructive Surgery. 1999; 104(1):205-214
Lemperle G, Tenemhaus M, Knapp D, Lemperle SM. The direction of optimal skin incisions derived from striae distensae. Plastic and Reconstructive Surgery. 2014; 13(6):1424-1434
Dufourmentel C, Talaat SM. The kite-flap. In: Transactions of the Fifth International Congress of Plastic and Reconstructive Surgery. Melbourne: Butterworth; 1971. p. 1223
Limberg AA. The Planning of Local Plastic Operations on the Body Surface. Theory and Practice. Lexington: Collamore; 1984
Alvarado A. Reciprocal incisions for closure of circular skin defects. Plastic and Reconstructive Surgery. 1981; 67:482-491
Alvarado A. Designing flaps for closure of circular and semicircular skin defects. Plastic and Reconstructive Surgery. Global Open. 2015. DOI: 10.1097/GOX.0000000000000583; Published on Line
Alvarado A. Three surgical cases about the use of pedicled flaps for closure of circular and semicircular skin defects. Plastic Surgery and Modern Techniques. 2019; 6:145. DOI: 10.29011/2577-100045
Sakai S, Soeda S. L-shaped flap for triangular slin defects. British Journal of Plastic Surgery. 1988; 41:628-632
Mutaf M, Bekericiouglu M, Erkulu I, Bulut O. A new technique for closure of large meningocele defects. Annals of Plastic Surgery. 2007; 59:538-543
Filho EA, Wojcik L, Brenner FA, Santamaria JR, Werner B. Cutaneous triangular excision with primary closure. Surgical and Cosmetic Dermatology. 2011; 3:31-35
Alvarado A. A simple method for closure of triangular skin defects. Advances in Plastic & Reconstructive Surgery. 2017; 1(1):100-107