The Internal Pudendal Artery Perforator Flap

RECONSTRUCTIVE The Internal Pudendal Artery Perforator Flap: Free-Style Pedicle Perforator Flaps for Vulva, Vagina, and Buttock Reconstruction Ichiro Hashimoto, M.D., Ph.D. Yoshiro Abe, M.D., Ph.D. Hideki Nakanishi, M.D., Ph.D. Tokushima, Japan Background: Reconstruction of the vulva, vagina, and buttocks following cancer ablation is challenging. Restoring the shape, volume, and function is the key to the best reconstruction for these regions. Perineal reconstruction with a free-style flap based on skin perforators from the internal pudendal artery was evaluated. Methods: The internal pudendal artery perforator flap was designed based on information about the skin perforators. The flap base contained the arterial sounds, which were identified by a handheld Doppler device, on and around the ischiorectal fossa. Types of flaps used included propeller flaps, traditional transposition flaps, and V-Y advancement flaps. Results: Seventy-one flaps were transplanted in 45 cases. The reconstructed regions included vulvar skin in 36 cases, buttock skin in 10 cases, vagina in nine cases, anus in six cases, and pelvic cavity in six cases. The flaps were transplanted in the lithotomy or prone position. Sixty-seven of these flaps survived completely. Four flaps showed partial necrosis, but no total flap failures occurred. Thinning of the fatty tissue of the flap was performed in all cases except pelvic cavity reconstruction. An additional operation to remove bulkiness of the flaps following the initial reconstruction was required in one case. Propeller flaps, transposition flaps, and V-Y flaps were used in 35, three, and seven cases, respectively. Conclusions: This study revealed that the blood circulation of this flap is reliable and that it offers suitable volume not only for vulvar, vaginal, and anal reconstruction, which requires a thin flap, but also for pelvic floor reconstruction, which requires flap volume. (Plast. Reconstr. Surg. 133: 924, 2014.) CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV. R econstruction of the vulva, vagina, and buttocks is challenging. The shape and function of these regions are complicated, and the shape is closely related to function. Tissue volume around these regions is vital for maintaining a symmetrical shape and function after reconstructive surgery. Restoring the shape, volume, and function is the key to the best reconstruction for these regions. Furthermore, this region can easily be affected by movements of the lower legs From the Department of Plastic and Reconstructive Surgery, University of Tokushima Graduate School. Received for publication June 21, 2013; accepted October 9, 2013. Presented in part at the Fifth Congress of the World Society for Reconstructive Microsurgery, in Okinawa, Japan, June 25 through 27, 2009. Copyright © 2014 by the American Society of Plastic Surgeons DOI: 10.1097/PRS.0000000000000008 924 and can become infected by feces, urine, and vaginal discharge. Reliable skin closure to facilitate rapid healing is also important for early discharge from the hospital. Perforator flaps offer a safe and reliable procedure in reconstructive plastic surgery.1,2 The concept of a free-style perforator flap, where a flap is harvested based only on preoperative Doppler signal mapping, was introduced by Wei and Mardini.3 Since then, free-style pedicled perforator flaps based on different pedicles have been advocated, and their clinical usefulness and safety have been demonstrated.4–7 It has been shown in previous anatomical studies that the perineal region is nourished by the internal pudendal artery.8,9 Since it was reported Disclosure: The authors have no financial interest to declare in relation to the content of this article. www.PRSJournal.com Volume฀133,฀Number฀4฀•฀Internal฀Pudendal฀Artery฀Perforator฀Flap that a gluteal fold flap is nourished by the internal pudendal artery,10,11 clinical uses of flaps based on the internal pudendal artery have been published.12,13 However, to the best of our knowledge, there are no anatomical or theoretical analyses or case series of the clinical use of free-style perforator flaps based on the internal pudendal artery. The purpose of this study was to evaluate perineal reconstruction with a free-style flap based on skin perforators from the internal pudendal artery. The internal pudendal artery perforator flap was divided into different types according to the flap movement carried out, and each type was assessed. PATIENTS AND METHODS A retrospective review of 45 patients who had vulva, vagina, and buttock defect reconstructions with the internal pudendal artery perforator flap was performed. All operations were performed mainly by a single surgeon (I.H.) on consecutive cases at a single hospital (Tokushima University Hospital, Tokushima, Japan) over a 13-year period (2000 to 2012). Patient data were gathered from hospital records, including patient demographics, tumors, treatments, and outcomes. Anatomy for Flap Design and Elevation The flap design and surgical procedure were performed based on anatomical studies of the internal pudendal artery and its skin perforators.10,11 To summarize, the internal pudendal artery originates from the internal iliac artery in the pelvis, runs in a deeper layer than the sacrotuberous ligament, and emerges under the ischial tuberosity toward the ischiorectal fossa (Fig. 1). Three to five skin perforators branch off the internal pudendal artery in the fossa and nourish the perineal skin directly (Figs. 1 and 2). The ischiorectal fossa is anatomically located in the triangle (the vascular triangle) formed by the ischial tuberosity, the apex of the coccyx, and the vaginal orifice or scrotum (Fig. 1). The line from the ischial tuberosity to the vaginal orifice indicates the posterior edge of the urogenital diaphragm. The line between the ischial tuberosity and the apex of the coccyx indicates the margin of the gluteus maximus muscle. The line from the vaginal orifice to the apex of the coccyx indicates the anococcygeal ligament. Arterial flow sounds are audible with a handheld Doppler device in and around this triangle. Flap Design The following types of internal pudendal artery perforator flap can be used (Fig. 1). The flap pedicle is designed to contain the Doppler signals in all types. Type I-1, Propeller Flap The propeller flap can be designed in any direction on the basis of Doppler signals. In the case of a flap rotated more than 90 degrees, the propeller flap is better than a conventional transposition Fig. 1. Significant markers for the anatomy and design of the internal pudendal artery perforator flap. Type I is a propeller flap and type II is an advancement flap. The vascular triangle consists of the ischial tuberosity (IT), the apex of the coccyx, and the vaginal orifice or scrotum. The triangle shows the location of the ischiorectal fossa. IPA, internal pudendal artery. 925 Plastic and Reconstructive Surgery฀•฀April฀2014 Fig. 2. Frontal section of the pelvis. The internal pudendal artery (IPA) runs through the pudendal canal behind the rims of the ischium. Perforator vessels branch off from the internal pudendal artery and penetrate the obturator fascia and the sacrotuberal ligament and travel through the thick fatty tissue in the ischiorectal fossa (IF) to the buttock skin. GMM, gluteus maximus muscle; IT, ischial tuberosity. flap to avoid dog-ear formation around the flap pedicle and to allow easy movement of the entire flap. When a large flap is required, the flap should be designed on the gluteal sulcus. Type I-2, Transposition Flap In the case of a flap rotated less than 90 degrees, a traditional transposition flap without skin dissection of the flap base can be used. Type II, Advancement Flap The V-Y advancement flap can be designed on the basis of Doppler signals. The long axis of the flap is placed along the gluteal sulcus to make it easy for the donor site to be closed. When the defect in the perineal region is wide, but not deep enough to reach the vagina or pelvic space, this type of flap is suitable for covering it. Surgical Technique The flap is elevated with sharp dissection from the distal portion toward the vascular pedicles either subfascially or suprafascially. Fascia can be found on the thigh and on the gluteus maximus muscle. However, fascia at the ischiorectal fossa is very deep on the levator ani and sphincter ani muscles and cannot be found with usual flap elevation (Fig. 2). The skin perforators from the internal pudendal artery are present in the thick fatty tissue of the ischiorectal fossa. The soft tissue around the pedicles is incised with blunt dissection until the flap reaches the defect without any tension. We have dealt with seven cases in which the major part of the vascular triangle was resected 926 with tumor ablation. In such cases, if the fatty tissue in the triangle is preserved and the Doppler sound on the skin is confirmed around the defect, the flap can be elevated by connecting the vascular pedicle in the fatty tissue to the base of the skin flap. After flap elevation, the fascia and the fatty tissue of the distal part, which does not contain the pedicle vessels, can be thinned to adjust flap volume. Because the skin of this flap has a direct blood supply from the perforator vessels,10 thinning can be performed without damage to the subcutaneous vascular system. When there is a defect of the pelvic floor and the pedicle vessels are preserved after abdominoperineal resection, the flap can be elevated and transplanted to the defect (Fig. 3, above). When the anal canal is resected with the posterior wall of the vagina, the flap skin can be used to reconstruct the vaginal wall. The deepithelialized flap and fatty tissue, which is not thinned, can be used to fill the pelvic space (Fig. 3, below). RESULTS A total of 71 flaps were performed in 45 cases. The age at the time of surgery ranged from 19 to 84 years (mean, 62 years). The patients were 38 women and seven men. The causes for the defects were malignant neoplasm in 42 cases and benign disease including scar or fistula in three cases. The reconstructed regions were vulvar skin in 36 cases, buttock skin in 10 cases, vagina in nine cases, anus in six cases, and pelvic cavity in six cases (Table 1). The flaps were elevated Volume฀133,฀Number฀4฀•฀Internal฀Pudendal฀Artery฀Perforator฀Flap Fig. 3. (Above) Frontal section of the pelvis after abdominoperineal resection. The flaps are elevated with the residual perforator vessels from the internal pudendal artery to be inserted into the defect of the pelvic cavity. (Below) Sagittal section of the pelvis after abdominoperineal resection. The back wall of the vagina is reconstructed with the internal pudendal artery perforator flap. The pelvic space is filled with the deepithelialized skin and fatty tissue of the flap. iPap, internal pudendal artery perforator. Table 1. Defect Location and Types of Flaps Used Type of Transplanted Flaps Location of Defects Vulvar skin Buttock skin Vagina Anus Pelvic cavity No. of Cases Propeller Transposition Advancement 36 10 9 6 6 28 9 6 6 5 2 1 0 0 0 6 0 3 0 1 and transplanted in the lithotomy position in 41 cases and in the prone position in four cases. In those four cases, the anus and buttock skin were reconstructed with a propeller flap. A permanent artificial anus was made concomitantly with the reconstruction in six cases. A temporary artificial anus was made in nine cases and could be closed in five cases. In the other cases, the reasons for not closing it were the patient’s age and the lack of a request for an additional operation, and they did not include functional problems because of flap necrosis or bulkiness. Complete flap survival was obtained in 67 flaps. Partial flap necrosis was seen in four cases, but 927 Plastic and Reconstructive Surgery฀•฀April฀2014 no total flap failure occurred. Gracilis muscle flap transplantation was required for partial flap necrosis in one case, but additional surgery was not needed in the other three. Minor wound dehiscence, which prolonged healing time but was treated with dressings, was observed in five cases. Minor wound dehiscence meant separation of the wound because of tension to the wound after moving the legs without flap necrosis. Thinning of the fatty tissue of the flap was performed in all cases except for six requiring reconstruction of the pelvic cavity. An additional operation to remove flap bulkiness following initial reconstruction was needed in one case. Propeller flaps were used in 35 cases and 56 flaps (Figs. 4 through 6). These flaps were 4 to 7 cm in width (mean, 5.6 cm) and 8 to 18 cm in length (mean, 13.9 cm). Transposition flaps were used in three cases and four flaps (Fig. 7). These flaps were 2 to 5 cm in width (mean, 3.3 cm) and 5 to 12 cm in length (mean, 6.8 cm). V-Y advancement flaps were used in seven cases and 11 flaps (Fig. 8). These flaps were 5 to 10 cm in width (mean, 6.8 cm) and 8 to 15 cm in length (mean, 11.9 cm). The major part of the skin in the vascular triangle was resected for cancer ablation in seven cases and nine flaps. All of these survived completely (Figs. 4 and 6). The relationship between defect location and type of flap and the summary of each type of flap are shown in Tables 1 and 2. DISCUSSION Study of the classification and terminology of perforator flaps is ongoing.14,15 Perforator vessels are divided into three types14: (1) indirect muscle or myocutaneous perforators that travel through muscle; (2) indirect septal or septocutaneous perforators that travel through the intermuscular septum; and (3) direct perforators that travel through the fatty tissue only. The skin perforators of the internal pudendal perforator flap are categorized as direct perforators. In cases where the perforator flaps are elevated on muscles, perforator vessels can usually be isolated on or under the deep fascia under subcutaneous fatty tissue.5–7 In the course of elevation of the internal pudendal artery perforator flap, however, the fascia cannot be found in the ischiorectal fossa, which has a very thick fat layer. Careful attention is recommended for elevation of the perforator flap around voluminous tissue layers, such as the lower back and gluteal region, because the preoperative investigation for skin perforators with a handheld Doppler device is 928 Fig. 4. (Above) A 65-year-old woman underwent wide excision of extramammary Paget disease. The defect spread to the right labia minora, the labia majora, the posterior femoral region, and the perineal region between the vagina and anus. The major part of the vascular triangle was resected. (Center) A bilobed propeller flap (6 × 12 cm) was elevated, with fatty tissue preserved in the ischiorectal fossa. The fatty tissue of the distal part of the flap was resected to achieve symmetrical reconstruction. The gluteus maximus muscle can be seen from the flap donor site. (Below) Postoperative appearance after 6 months. The flap has survived completely. The patient underwent concomitant construction of an artificial anus, which was closed with confirmation of no recurrence and good anal function 12 months after the initial reconstruction. Volume฀133,฀Number฀4฀•฀Internal฀Pudendal฀Artery฀Perforator฀Flap Fig. 5. (Above, left) A 73-year-old woman underwent wide excision of a squamous cell carcinoma on the left side of the anal canal. (Above, right) The anus, anal canal, rectum, fatty tissue of the left ischiorectal fossa, and posterior wall of the vagina with buttock skin were resected. (Center, left) One flap (7 × 15 cm) was elevated from the right gluteal sulcus. The flap was inserted into the pelvic cavity to fill the space after resection of the rectum and to create the posterior wall of the vagina. (Center, right) Another skin flap, which is not the internal pudendal artery perforator flap but an advancement flap from the buttock side, is elevated on the left gluteus maximus muscle and advanced to the defect. (Below) Postoperative appearance after 3 months. The complicated defect including the pelvic space has been reconstructed. not always accurate.7,16 We think that it is unsafe and unnecessary to attempt to look at the perforators in the thick fatty tissue in the ischiorectal fossa because they come out of the skin through thick fatty tissue with no specific relationship to muscle or fascia. Although the pedicle vessels are not dissected, this flap should be elevated completely from the fascia around the perineal region except for the ischiorectal fossa to be transferred without any tension. With respect to the usual elevation of propeller flaps, aggressive dissection or skeletonizing the perforator vessels 929 Plastic and Reconstructive Surgery฀•฀April฀2014 Fig. 6. (Above, left) A 66-year-old woman with extramammary Paget disease underwent wide excision. (Above, right) The anus, anal canal, rectum, and vaginal wall with skin of the external genitalia were resected. The major part of the vascular triangle was resected. (Below, left) Two flaps (5 × 12 cm) from both sides of the gluteal fold were elevated with flap pedicles connected with the ischiorectal fossa. (Below, right) The flaps have survived completely. Postoperative appearance after 6 months. The complex defect including the pelvic space has been successfully reconstructed. is not safe and is recommended only when the flap cannot be reached and rotated enough to a defect.5–7 Skeletonizing the perforator is needed to gain the length of the pedicle vessel to rotate the flap without vessel kinking. Because the base of the perforators from the internal pudendal artery is deep enough and protected by the thick fatty tissue, the propeller type flap can be safely rotated without aggressive dissection of the perforator vessels. The vascular triangle is a good marker for the flap to contain the skin perforators. In this series, flaps whose base skin was almost totally resected, because the major part of the triangle was resected, survived completely through preservation of the fatty tissue between the ischiorectal fossa and the flap base. Reasons for survival of these flaps are that some skin perforators spread out over the gluteus maximus9 and that this area has a very thick vascular network.8–10,17–19 Furthermore, the perforasome theory has recently 930 revealed that one perforator has a wide vascular territory through linking vessels and communicating branches in the adipose layer.20 Preservation of fatty tissue around the perforators can help maintain the linking vessels to improve vascularity to the flap. We have used only handheld Doppler imaging to detect the skin perforators and do not have experience using computed tomographic or magnetic resonance angiography preoperatively. We think that the perforators for the internal pudendal artery are quite reliable and that angiography is not needed at the time of reconstruction because we can confirm damage to the perforator at the time of surgery. However, angiography can be useful in cases that have already undergone cancer ablation around the pedicle vessels. This study showed that the blood circulation of the internal pudendal perforator flap is reliable even after resection of the entire fascia Volume฀133,฀Number฀4฀•฀Internal฀Pudendal฀Artery฀Perforator฀Flap Fig. 7. (Above) A 36-year-old woman with squamous cell carcinoma on the posterior wall of the vagina underwent wide excision. Two transposition flaps (3 × 5 cm) were designed. (Below) Postoperative appearance after 6 months. The posterior wall of the vagina has been reconstructed with the two flaps. and part of the fatty tissue, and that this flap offers suitable volume not only for vulvar, vaginal, and anal reconstruction, which requires a thin flap, but also for pelvic floor reconstruction, which requires flap volume. Furthermore, there are other advantages. The pedicle vessels are very near the defect. This makes it easy to use the whole flap for covering and filling different defects. The internal pudendal artery is very deep and concealed in the pudendal canal. This means that this artery is not damaged by usual surgical ablation of cancer. This flap can be elevated in the lithotomy or prone position. This shows that flap transplantation can be performed in the same position as the tumor ablation without positional change. The propeller type flap has a benefit in that voluminous tissue or a long skin paddle can be moved to defects from the gluteal sulcus and fold. However, the width of this type of flap must be no more than 7 cm to close the flap donor site. The V-Y type of flap has another advantage in that wider skin flaps can be moved to wide Fig. 8. (Above) A 77-year-old woman underwent wide excision of squamous cell carcinoma on the right wall of the vagina. (Center) One V-Y advancement flap (6 × 10 cm) was elevated and inserted into the vagina to reconstruct the right side wall. (Below) Postoperative appearance after 8 months. Symmetrical reconstruction has been achieved. defects. However, it is difficult for a deep defect to be filled by this flap because its limited length prevents it from being advanced and moved. It is important to completely elevate the V-Y flap from the fascia around the ischiorectal fossa to prevent it from being brought back to the donor site and to avoid dehiscence of the wound with leg movement. 931 Plastic and Reconstructive Surgery฀•฀April฀2014 Table 2. Summary of Each Type of Flap Width (cm) Type of Flap No. of Cases No. of Flaps Mean Propeller Transposition Advancement 35 3 7 56 4 11 5.6 3.3 6.8 Reconstruction of the vulva, vagina, and perineal region with myocutaneous and fasciocutaneous flaps from the thigh started in the 1980s.21,22 In the 1990s, fasciocutaneous flaps supplied by the superficial perineal artery, which is the terminal branch of the internal pudendal artery, were reported.18,19,23 These flaps resulted in more reliable reconstruction than skin grafting, but they had some drawbacks, including flap bulkiness because of the muscle components, severe scars on the thigh, pedicle vessels far from the defect, or small flap skin area. Since 2000, perforator flaps such as the anterolateral thigh flap and the deep inferior epigastric perforator flap have been used for perineal reconstruction.24,25 Currently, many flaps can be chosen to achieve the best size and volume for perineal defects, keeping in mind donor-site morbidity. Anatomical knowledge and experience in flap elevation have been making perineal reconstruction safer, easier, and more reliable. The quality of perineal reconstruction is related to restoring shape, volume, and function. The internal pudendal artery perforator flap is a good option for achieving reliable reconstruction in the perineal region. CONCLUSIONS The findings of the present study demonstrate that various defects of the vulva, vagina, and perineal regions can be successfully reconstructed with the internal pudendal artery perforator flap, and that this free-style pedicle perforator flap has many benefits in the reconstruction of these regions. Ichiro Hashimoto, M.D., Ph.D. Department of Plastic and Reconstructive Surgery University of Tokushima Graduate School 2-50-1 Kuramoto-cho Tokushima 770-8503, Japan [email protected] REFERENCES 1. Wei FC, Celik N. Perforator flap entity. Clin Plast Surg. 2003;30:325–329. 932 Length (cm) Range Mean Range 4.0–7.0 2.0–5.0 5.0–10.0 13.9 6.8 11.9 8.0–18.0 5.0–12.0 8.0–15.0 Rotation (degrees) Mean Range 131 90 — 90–180 — — 2. Geddes CR, Morris SF, Neligan PC. Perforator flaps: Evolution, classification, and applications. Ann Plast Surg. 2003;50:90–99. 3. Wei FC, Mardini S. Free-style free flaps. Plast Reconstr Surg. 2004;114:910–916. 4. Hallock GG. Doppler sonography and color duplex imaging for planning a perforator flap. Clin Plast Surg. 2003;30: 347–357, v. 5. Lecours C, Saint-Cyr M, Wong C, et al. Freestyle pedicle perforator flaps: Clinical results and vascular anatomy. Plast Reconstr Surg. 2010;126:1589–1603. 6. D’Arpa S, Cordova A, Pignatti M, Moschella F. 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First cutaneous branch of the internal pudendal artery: An anatomical basis for the so-called gluteal fold flap. Okajimas Folia Anat Jpn. 2001;78:23–30. 12. Sinna R, Benhaim T, Qassemyar Q, Bréhant O, Mauvais F. Double L-shaped free-style perforator flap for perineal and vaginal reconstruction after cylindrical abdominoperineal resection. J Plast Reconstr Aesthet Surg. 2010;63: 1740–1743. 13. Sinna R, Alharbi M, Assaf N, et al. Management of the perineal wound after abdominoperineal resection. J Visc Surg. 2013;150:9–18. 14. Blondeel PN, Van Landuyt K, Hamdi M, Monstrey SJ. Perforator flap terminology: Update 2002. Clin Plast Surg. 2003;30:343–346, v. 15. Hallock GG. Direct and indirect perforator flaps: The history and the controversy. Plast Reconstr Surg. 2003;111:855– 865; quiz 866. 16. Muneuchi G, Matsumoto Y, Tamai M, et al. Rhomboid perforator flap for a large skin flap due to lumbosacral meningocele. Ann Plast Surg. 2005;54:670–672. 17. Salmon M. The external genitalia and the perineum. In: Taylor GI, Tempest MN, eds. Arteries of the Skin. Edinburgh: Churchill Livingstone; 1988:109–127. 18. Wee JT, Joseph VT. A new technique of vaginal reconstruction using neurovascular pudendal-thigh flaps: A preliminary report. Plast Reconstr Surg. 1989;83:701–709. Volume฀133,฀Number฀4฀•฀Internal฀Pudendal฀Artery฀Perforator฀Flap 19. Yii NW, Niranjan NS. Lotus petal flaps in vulvo-vaginal reconstruction. Br J Plast Surg. 1996;49:547–554. 20. Saint-Cyr M, Wong C, Schaverien M, Mojallal A, Rohrich RJ. The perforasome theory: Vascular anatomy and clinical implications. Plast Reconstr Surg. 2009;124:1529–1544. 21. McCraw JB, Massey FM, Shanklin KD, Horton CE. Vaginal reconstruction with gracilis myocutaneous flaps. Plast Reconstr Surg. 1976;58:176–183. 22. Hurwitz DJ, Swartz WM, Mathes SJ. The gluteal thigh flap: A reliable, sensate flap for the closure of buttock and perineal wounds. Plast Reconstr Surg. 1981;68:521–532. 23. Woods JE, Alter G, Meland B, Podratz K. Experience with vaginal reconstruction utilizing the modified Singapore flap. Plast Reconstr Surg. 1992;90:270–274. 24. Luo S, Raffoul W, Piaget F, Egloff DV. Anterolateral thigh fasciocutaneous flap in the difficult perineogenital reconstruction. Plast Reconstr Surg. 2000;105: 171–173. 25. Wang X, Qiao Q, Burd A, et al. A new technique of vaginal reconstruction with the deep inferior epigastric perforator flap: A preliminary report. Plast Reconstr Surg. 2007;119:1785– 1790; discussion 1791. Plastic Surgery Level of Evidence Rating Scale—Therapeutic Studies Level of Evidence I II III IV V Qualifying Studies Highest-quality, multicentered or single-centered, randomized controlled trial with adequate power; or systematic review of these studies High-quality, randomized controlled trial; prospective cohort or comparative study; or systematic review of these studies Retrospective cohort or comparative study; case-control study; or systematic review of these studies Case series with pre/post test; or only post test Expert opinion developed via consensus process; case report or clinical example; or evidence based on physiology, bench research, or “first principles” Find out more from the “Evidence-Based Medicine: How-to Articles” Collection at www.PRSJournal.com 933