Internal pudendal perforator artery–based gull wing flap for vulvovaginal 3D reconstruction after tumour excision: a new flap

Abstract

Various skin tumours such as squamous cell carcinoma and extramammary Paget's disease can occur in the vulval area, and reconstruction of the vulval area can be a very challenging task.

A retrospective analysis of vulvar reconstruction using the new method ‘internal pudendal perforator artery–based gull wing flap’ was performed from April 2012 to December 2013. A perforator vessel from the internal pudendal artery was detected with a portable Doppler and marked, and this was the pivot point around which the flap was rotated. The flap was rotated by more than 150°–180° internally, and the labium and the external wall of the vagina were reconstructed with sufficient volume.

Anatomical and aesthetic reconstruction of the labium and the vagina was performed without serious complications. Functional and aesthetic vulvar reconstruction can be achieved by using a flap that provides sufficient volume of the labium. Our new technique, the ‘internal pudendal perforator artery–based gull wing flap’, is good and it can be used to reconstruct a functional and aesthetically acceptable vulvovagina for large defect wound after tumour excision.

Purpose

Various skin tumours such as squamous cell carcinoma and extramammary Paget's disease can occur in the vulval area; however, the reconstruction of the vulval area is very challenging. A wound in the perineal area is easily contaminated with secretion from the exocrine glands in the vagina. Because of the vulnerability to contamination and the possibility of adjuvant radiation therapy after tumour excision, it is crucial to cover the defect with a durable tissue. Previously, various fasciocutaneous flaps, including the pudendal thigh flap, the perineal artery axial flap, the vulvoperineal fasciocutaneous flap, the medial thigh flap and the gluteal thigh flap, have been introduced by plastic surgeons 1, 2, 3, 4, 5, 6. Earlier, we also introduced the methods of gluteal fold V‐Y advancement flap in 2006 7 and the modified gluteal fold V‐Y advancement flap in 2013 8. However, the drawbacks of these methods are the need for a larger operating field that requires wide dissection and extended operation time. Also, such drawbacks might hinder patients from short recovery and delay postoperative adjuvant radiation therapy. Hence, we propose a novel method to overcome these drawbacks.

Methods

Patients

A retrospective analysis of vulvar reconstruction using the new technique ‘internal pudendal perforator artery–based gull wing flap’ was performed from April 2012 to December 2013. A total of nine patients were enrolled in this study (Table 1). The causes for performing vulvar reconstruction were squamous cell carcinoma in five patients, extramammary Paget's disease in two patients and malignant melanoma in two patients. Using the classification of vaginal defects proposed by Cordeiro et al. 9 only patients with type I defects were included, whereas those with type IIa or type IIb defects were excluded (Figure 1).

Table 1.

Summary of the cases

Patient number	Age (years)	Diagnosis	Defect size (cm2)	Complication
1	79	Extramammary Paget's disease	10 × 5 cm	None
2	73	Malignant melanoma	8 × 5 cm	None
3	47	Squamous cell carcinoma	7 × 4 cm	None
4	68	Squamous cell carcinoma	8 × 6 cm	Partial necrosis
5	73	Squamous cell carcinoma	8 × 8 cm	None
6	65	Squamous cell carcinoma	7 × 5 cm	None
7	72	Extramammary Paget's disease	9 × 4 cm	None
8	53	Squamous cell carcinoma	8 × 4 cm	None
9	71	Malignant melanoma	10 × 4 cm	None

Figure 1.

Schematic illustration of our new flap. The internal pudendal artery originates from the internal iliac artery, passes beneath the sacrotuberous ligament and through a layer deeper than the superficial transverse perineal muscle and then reaches the perivulvar area. Within this area, the internal pudendal artery runs through a layer deeper than the perineal membrane towards the pubic area while supplying the urethral opening and the clitoris. We were able to design a flap using these perforators as the pedicle artery.

Wide excision of the tumour was first performed at the Department of Gynecology. After that, the patient was introduced to the operating team from the Department of Plastic and Reconstructive Surgery for undergoing reconstruction. Each operation was performed under general anaesthesia and by a single surgeon (Jong Won Rhie).

Institutional Review Board (Catholic Medical Center Office of Human Research Protection Program) approved this study.

Relevant anatomy

The authors were able to design a new flap by performing an investigation of the anatomy of the internal pudendal artery and its perforators. The internal pudendal artery originates from the internal iliac artery, passes beneath the sacrotuberous ligament and through a layer deeper than the superficial transverse perineal muscle and then reaches the perivulvar area. Within this area, the internal pudendal artery runs through a layer deeper than the perineal membrane towards the pubic area while supplying the urethral opening and the clitoris. We were able to design a flap by using these perforators as the pedicle artery (Figure 1). After vulvectomy, if the vaginal defect is limited only to type I defect, the internal pudendal artery can be preserved, although some of the superficial arteries such as the perineal and labial arteries could be damaged. Perforator vessels arising from the internal pudendal artery around the clitoris can be easily detected using a hand‐held portable Doppler.

Surgical techniques

Each flap was elevated with the patient in the lithotomy position, which could be maintained after vulvectomy. Clitoris is an important landmark of the new flap. It was important to place the base of the flap under the vertical level of the clitoris because if the level of the flap was higher, there would be difficulty in rotating the flap and insetting the flap into the designated area and the possibility of kinking of the pedicled artery may increase. We created the flap from the inguinal crease area according to the defect size (Figures 1, 2, 3, 4). After that, we marked the perforator vessel arising from the internal pudendal artery that was detected with a hand‐held portable Doppler, and this was the pivot point around which the flap was rotated. We named it the ‘Gull wing flap’ because of its resemblance to a gull spreading its wings. The width of the flap was not more than 6–7 cm to achieve primary closure of the donor site. The length of the flap depended on the distance between the pivot point and the defect area; but 2–3 cm extension was required for obtaining the sufficient volume for labium reconstruction. Incision was carried down to the underlying muscle fascia and inguinal ligament, and the gull wing flap was mobilised by suprafascial or subfascial dissection, but saved around the traced area of the perforators (Figure 2B). Too much skeletonisation was avoided because it could lead to flap necrosis after flap rotation. The flap was internally rotated by more than 150 to 180 degrees and the reconstructed labium and external vaginal wall had sufficient volume without any tension (Figures 2C and 3C). The transposition flap was then secured to the vaginal wall margin with a #3‐0 Catgut suture and a #4‐0 Vicryl suture. We routinely performed a watertight closure of the vaginal wall to prevent infections resulting from bacterial contamination and vaginal discharge. A negative suction drain was inserted bilaterally beneath the flap base to the donor site. Primary closure of both donor sites was performed.

Figure 2.

A 73‐year‐old woman underwent wide excision of squamous cell carcinoma. The size of the defect was 8 × 8 cm², and the extent of the defect ranged from the labium to the vaginal wall. (A) Preoperative design of the flap and marking of the pedicle artery. (B) Incision was carried down to the underlying muscle fascia and inguinal ligament, and the gull wing flap was mobilised by suprafascial dissection, but saved around the traced area of perforators. Arrow indicates the perforator vessel. (C) Postoperative view obtained at 3 days after surgery.

Figure 3.

A 47‐year‐old woman underwent wide excision of squamous cell carcinoma. After wide resection was performed at the Department of Gynecology, the size of the defect was measured as 7 × 4 cm² and the extent of the defect ranged from the labium to the vaginal wall. (A) Preoperative design of the flap and marking of the pedicle artery. (B) Direct exposure of the clitoris and urethral opening can be observed. Defect area extended to the vagina. (C) Postoperative view at 8 days after surgery.

Figure 4.

A 68‐year‐old woman underwent wide excision of squamous cell carcinoma. The size of the defect was 8 × 6 cm², and the extent of the defect ranged from the labium to the vaginal wall. (A) Intraoperative view obtained after flap elevation. (B) Ecchymosis and partial necrosis on the left side were observed at 4 days after surgery. (C) After regular use of Sitz bath, spontaneous healing was seen at 1 month after surgery.

Postoperative care

During the first postoperative week, intermittent pneumatic compression devices were applied to both lower extremities to avoid a deep vein thrombosis. The patients were placed on a pressure mattress with their legs abducted and knees bent. The patients started walking within 1–2 days after the F‐catheter was removed. Compression dressing was also removed and washing was performed using Sitz bath. The patients were discharged within 5–7 days after the surgery. Because both thighs, buttocks and inguinal areas were tension free, the patients did not have any difficulty in sitting and washing immediately on the first day after surgery.

Aesthetic score assessment

As our new flap encompasses optimal defect coverage and aesthetic reconstruction, we have evaluated its aesthetic aspect. An aesthetic score assessment survey was performed by a blinded third party physician (plastic surgeon) at 5–6 months postoperatively. We adopted and modified the measures for evaluating the aesthetic appearance of the female genitalia from the studies by Lloyd et al. 10 and Creighton et al. 11 The general assessment included symmetry, clitoral hooding, normal labial position and proportion and vaginal introital position and/or no evidence of ectropion. The surveyor gave 1 point for each criterion and classified it into one of the following three categories: good (4 points), satisfactory (3–2 points) and poor (1–0 points). Identical assessment was performed in patients who received the modified gluteal fold V‐Y advancement flap, which has been published previously by Rhie 8.

The differences in the scores between the two groups were statistically analysed by Mann–Whitney test. SPSS version 13.0 software (SPSS Inc., Chicago, IL) was used.

Results

Clinical information of the patients enrolled in this study is summarised in Table 1. The age of the patients ranged from 47 to 79 years. The follow‐up period ranged from 5 to 16 months. The size of the defect varied from 7 × 4 to 10 × 5 cm², and each defect was covered with bilateral flaps. No additional flap or skin graft was required. The average operation time was 2 hours. No severe complications such as total necrosis or any other conditions requiring immediate operation were reported. Partial flap necrosis was observed in one patient; but the wound healed spontaneously (Figure 4). Results of the aesthetic score survey were very satisfactory (Table 2). On statistical analysis, the gull wing flap showed superior results compared with the previous method (the modified gluteal fold V‐Y advancement flap). Scores in the two study groups showed a statistically significant difference (P < 0·01). The tissue texture of the flap showed great resemblance to the original structure, and it provided excellent aesthetic and functional results. Furthermore, direct exposure of the clitoris and the vaginal wall was minimised, resulting in a functional benefit during sexual intercourse (Figure 5). Five out of the nine patients were required to undergo additional radiation therapy, and all of them were able to receive radiation therapy within 2–4 weeks after the surgery.

Table 2.

Aesthetic score analysis of two groups at 6 months postoperatively

Aesthetic score	Gull wing flap (N = 9)	Modified gluteal fold V‐Y advancement flap (N = 11)
4 (good)	2	0
3–2 (satisfactory)	5	6
1–0 (poor)	0	5
Average score*	3·14	1·73

^* P value < 0·01; average: statistically significant between the two groups.

Figure 5.

(Above‐gluteal fold V‐Y advancement flap) Direct exposure of the vaginal and urethral opening and clitoris can be observed. (Below‐gull wing flap) Postoperative view obtained at 6 months after surgery. Reconstructed labium with sufficient volume shows clitorial hooding, proper labial position and proportion and vaginal introital position. The extent of the operation scar is minimal and the donor site scar is hidden within the inguinal fold.

Discussion

The primary purpose of vulvovaginal reconstruction is to achieve proper coverage of the defect area. Although numerous studies and various methods have been developed, the functional and aesthetic aspects such as minimal scarring, preserving sexual function and enabling patients to walk without difficulty are the important considerations. Furthermore, the possible need of adjuvant radiation therapy mandates surgeons to minimise the operation field to yield faster wound healing allowing the patients to proceed to the next treatment. In order to achieve this, it is necessary to design a flap that provides sufficient labial volume and closure with minimal tension.

We previously introduced the method of gluteal fold V‐Y advancement flap in 2006 7 and the modified gluteal fold V‐Y advancement flap in 2013 8. Using these methods, various types of vulvovaginal defects can be covered and postoperative scars can be hidden within the gluteal folds. However, the drawbacks of these methods are the need for a larger operating field that requires wide dissection and longer operation time. In addition, although the advancement flap provides a tensionless closure during the immediate postoperative state, skin tension gradually develops after a time period, resulting in the exposure of the vaginal mucosa. Vaginal ectropion causes excessive vaginal discharge leading to a poor quality of life. Also, this increases the likelihood of wound problems.

Clinical uses of the flaps based on the internal pudendal artery have been published 12, 13, 14, 15, 16. However, most of these methods mobilise the flaps within the thigh and the buttock area. The use of these methods resulted in a weak point, similar to that with the use of the gluteal fold V‐Y advancement flap.

Therefore, we propose a new flap based on the terminal branch of the internal pudendal artery as the pedicle. Because the pedicle is located in proximity to the defect area, rotating the flap using the pedicle as the pivot point will make a bulky point of both vulva and the labium resulting in an ideal reconstruction of the labium.

We included a group of patients who received the gluteal fold V‐Y advancement flap for comparing the aesthetic assessment because most of the female genitalia reconstructed using the flap based on the internal pudendal artery have a great resemblance to the female genitalia reconstructed using the gluteal fold V‐Y advancement flap 12, 13, 14, 15, 16. Because tissues from the thighs and buttocks are used, it is very challenging to reconstruct the sufficient volume of the labium and provide proper clitoral hooding. Also, tension and postoperative scarring might cause asymmetry of the labium and vaginal ectropion. The problems mentioned above have been considered as the objective measures 10, 11 for evaluating the female genitalia, and we applied the same criteria for evaluating the patients who received the gull wing flap.

Sufficient tissue coverage of the reconstructed labium will prevent vaginal ectropion, leading to satisfactory sexual intercourse and decreased spontaneous vaginal discharge, which provides an anatomical and aesthetic reconstruction. Because the reconstruction was done with sufficient tissue with durability, the possibility of wound problems after radiation therapy can be minimised. In addition, the donor site scar is hidden within the inguinal crease. Furthermore, because of tensionless closure, patients are able to begin ambulation within 1–2 days, and there is no limitation in the sitting position.

The main limitations of this study are the small number of patients and the possibility of anatomical variation of the internal pudendal artery. A further study on the anatomy of the internal pudendal artery is needed. According to the author's experience, a flap with perforators located in the base can be mobilised with a length of 15–20 cm and a width of 4 cm without partial necrosis on the distal end. If the perforators are located centrally, a larger flap can be ensured.

However, elevating the flap in this area cannot be a concern, because of the rich vascularity of perforator vessels. In the study by Kim et al. on the perineal perforator island flap, the authors noted this area as the ‘perforator‐rich area’ 16. Therefore, safe elevation is possible without extensive skeletonisation unlike other studies of perforator flap 17, 18. Only one case of partial necrosis was reported. We could estimate that the peforator artery might be located at a level higher than the suspected ideal pivot point, causing kinking of the artery after flap rotation. Hence, it is important to set the pivot point at the level of the clitoris. Perforators found at a level higher than that of the clitoris have an increased chance of causing flap necrosis because of the increased angle of rotation.

In conclusion, surgeons have to consider various functional and aesthetic aspects of vulvar reconstruction after tumour excision. Functional and aesthetic vulvar reconstruction can be achieved by using a flap that provides sufficient volume; however, the previously introduced methods did not satisfy this requirement. Our new technique, the ‘internal pudendal perforator artery–based gull wing flap’ is good and it can be used to perform a functional and aesthetic vulvovaginal reconstruction.