Usefulness of a Novel Pinwheel-shaped Incision Technique for Skin Tumor Excision

Summary:

Use of the fusiform ellipse excision technique is the most common method for direct closure of circular and elliptical defects. To prevent dog-ear formation after suturing, the long-axis length of the fusiform ellipse should be ≥3 times the transverse dimension and the angle formed by the 2 lines at both ends should be <30°. We devised a pinwheel-shaped incision technique for skin tumor excision that could reduce the scar size. We aim to present this technique and report its results and usefulness. We included 50 patients (55 cases; 54% women; mean age, 39.8 years) who underwent surgery using our pinwheel-shaped incision technique between January 2016 and December 2018. The incision line was designed like a pinwheel around the tumor, and the excess skin was trimmed after suturing at the center. The length-to-width ratio was calculated using the width before the operation and the suture length at the end of the operation. The operation site was primarily the face, and the maximum tumor width was 48 mm. The postoperative suture line length was 2.1 ± 0.2 (mean ± SD) times the width of the excision area. There were no complications such as skin necrosis, and no patient required reoperation because of dog-ear formation. Our new pinwheel-shaped incision technique allows shortening of the length-to-width ratio compared with that required in the conventional method and helps avoid dog-ear formation. We successfully used this technique in 55 cases and confirmed its usefulness.

INTRODUCTION

In plastic surgery, there is concern regarding deformations following suturing, such as dog-ear formation. Use of the fusiform ellipse excision technique is the standard method for excising skin tumors; it allows primary closure, resulting in a simple scar. To avoid dog-ear formation, the long axis of the fusiform ellipse should be ≥3 times the transverse dimension and the angle formed by the 2 lines at both ends should be <30°.^1,2 We devised a pinwheel-shaped incision technique for skin tumor excision that could reduce the scar size.

METHODS

Patients

We included 50 patients [55 cases; 23 men and 27 women; mean age, 39.8 years (range, 9 months–91 years)] who underwent surgery using our pinwheel-shaped incision technique between January 2016 and December 2018. This study was approved by the Japanese Red Cross Akita Hospital ethics committee (no. 720), and written informed consent was obtained from the study participants, including consent to participate and to publish the findings.

Surgical Method

The suture line (l) was marked through the center (o) of the tumor and aligned with the skin lines, such as relaxed skin tension lines (Fig. 1). It is often necessary to slightly curve the suture line to follow the skin lines. On the line, points a and b were placed equidistant from o. The distance from a and b to o should be the same as the transverse diameter of the excision area surrounding the tumor. From a and b, 2 tangential lines were drawn to the excision area periphery on both sides of the tumor. On the excision area periphery, points a´ and b´ were placed, which were the middle points between the tangency points and intersection points of ao or bo. The final excision area was defined by the excision area periphery, tangential lines, and aa´ and bb´ that formed a pinwheel shape around the tumor. The tumor was initially resected along the pinwheel design, followed by dermis suturing at the center of the incision line. This technique allowed for a flexible first/center suture point within the target zone (red zone). The excessive skin arising on both sides of the suture line was trimmed. In most cases, the amount of the excessive skin to be removed after suturing was not the same on both sides. After trimming, the dermis and skin were sutured from both ends. This technique is shown in Video 1. (See Video 1 [online], which displays the technique of this method in 2 cases. The first is of a 13-year-old teenage boy with a forearm nevus, and the second case is of a 10-month-old boy with a nevus in orbital area, requiring a flexible first/center suture point.) The length-to-width ratio was calculated using the width before the operation and the suture length at the end of the operation.

Fig. 1.

Surgical method using the pinwheel-shaped incision technique. A, The distance from a and b to o should be the same as the transverse diameter of the tumor. B, From a and b, 2 tangential lines are drawn to the tumor periphery on both sides of the tumor. C, On the tumor periphery, points a´ and b´ are placed, which correspond to the middle points between the tangency points and intersection points of ao or bo. D, The center suturing points are in the target zone (red zone). E, The shadow area is the trimmed area. F, After trimming, the dermis and skin is sutured from both ends.

Video 1. Pinwheel-shaped incision technique. Video 1 from “Usefulness of a Novel Pinwheel-shaped Incision Technique for Skin Tumor Excision”.

Download video file ^{(99.1MB, mp4)}

RESULTS

Table 1 presents the details of all patients. The operation site was primarily the face, and the maximum tumor width was 48 mm. There were no postoperative complications, and no patient required reoperation because of dog-ear formation. The postoperative suture line length was 2.1 ± 0.2 (mean ± SD) times the tumor width.

Table 1.

Details of Patients

Characteristic	Value
No. cases (No. patients)	55 (50)
Sex (men), n (%)	23 (46)
Age, y	40.0 (SD 22.7)
Operation site, n (%)
Face	29 (52.7)
Trunk	9 (16.3)
Lower extremity	8 (14.5)
Neck	3 (5.5)
Head	3 (5.5)
Upper extremity	3 (5.5)
Pathology, n (%)
Nevus cell nevus	32 (58.1)
Epidermal cyst	12 (21.8)
Fibroma	4 (7.3)
Others	7 (12.7)
Follow-up time, months	15.4 (SD 5.4)
Width of excision area, mm	11.6 (SD 6.9)
Suturing line length, mm	24.7 (SD 15.0)
Suturing line length per width	2.1 (SD 0.2)

Case Report

A 1-year-old boy had a nevus cell (18 × 11 mm) on the right side of the forehead. The pinwheel-shaped incision technique devised by us was used for tumor excision (Fig. 2A). The tumor was resected along the design, and then the dermis was sutured at the center of the incision line, which was determined with care to avoid right eyebrow distortion (Fig. 2B). After trimming the excessive skin arising on both sides, from both ends, sutures were placed. The suture line length was 23 mm, and the postoperative suture line length was 2.1 times the tumor width. The postoperative scar was inconspicuous 6 months following the surgery, with no eyebrow distortion (Fig. 2C).

Fig. 2.

Representative case. A, Design of the pinwheel-shaped incision. B, After the center suturing. The triangles at both ends indicate the parts to be trimmed. C, After 6 months, the postoperative scar is inconspicuous, and there is no distortion of the eyebrow.

DISCUSSION

The skin waste can reach up to 230% relative to the original circular area when using the fusiform ellipse excision.³ We observed that this excess skin resection is the reason for the long suture length. To avoid unnecessary skin resection, we did not perform complete resection during the first step; this helped in reducing the length-to-width ratio by 2.1 times on average (Table 1). The low skin waste helped reduce tension on the wound, leading to less scar expansion.

In fusiform ellipse excision, the wound closure direction is perpendicular to the major axis; sometimes the wound closure direction is unsuitable, particularly when the lesion to be resected is closer to a body part with a free edge such as eyelid and lip; therefore, it is necessary to consider the wound closure direction to avoid contracture deformity and distortion. This technique allows flexible wound closure without changing the suture line direction. In such a case, the first suture point deviates from the center point at the line and the suture line presents a slightly S-shaped curve. The S-shaped skin resection technique is sometimes used to change the wound closure direction, but the length of the suture line in our technique was shorter than that reported in the conventional S-shaped technique.^3,4 In contrast, the figure-of-8 suture approach aims to shorten the suture line,⁵ wherein the wound closure direction is perpendicular to the major axis and there is a possibility of ischemia at the wound edge. As our technique does not need a special suturing approach, such as the figure-of-8 suture approach, it is unlikely to cause ischemia.

The essential step in our technique is suturing from both ends to the center after skin trimming because the lengths of the 2 lines from the end to the first suturing point are unequal. A wound with unequal sides can be closed by equally dividing the excised skin of the longer side without dog-ear formation.⁶ Such a suturing approach occasionally causes fine wrinkling around the suture line that usually disappears in 2 weeks. The only limitation of our new technique is that the surgical procedure is slightly prolonged compared with the conventional method.

CONCLUSIONS

Our novel pinwheel-shaped incision technique allows shortening of the length-to-width ratio compared with that required in the conventional method and helps avoid dog-ear formation. We successfully performed this technique and confirmed its usefulness.

PATIENT CONSENT STATEMENT

Parents or guardians provided written consent for the use of the patients’ image.