Plastic surgery

PART IX

TRUNK AND LOWER EXTREMITY

CHAPTER 96  RECONSTRUCTION OF THE PERINEUM

PAUL H. TRAN AND VALERIE LEMAINE

INTRODUCTION

The goals of reconstructive surgery are restoration of both form and function, and this is especially important when dealing with reconstruction of the perineum. This area presents complex challenges to the plastic surgeon due to the close proximity of several key functional systems, namely the urinary, gynecologic, and gastrointestinal tracts.

The perineum can be conceptualized as a diamond-shaped space forming the outlet of the pelvis. It is confined within the following boundaries: (1) anterolaterally, by the inferior margin of the pubic symphysis and the borders of the ischiopubic rami; (2) posterolaterally, by the coccyx and the sacrotuberous ligaments (covered by the gluteus maximus muscles); and (3) laterally, by the two ischial tuberosities. It can be subdivided into two triangles, the urogenital triangle anteriorly and the anal triangle posteriorly. The perineum is highly vascular in both males and females. The superficial and deep external pudendal arteries arise from the femoral artery and provide the main blood supply to the skin and fascia of the anterior triangle. They divide into abdominal and perineal branches approximately 4 to 6 cm from the pubic symphysis. The main pedicle of the posterior triangle is the internal pudendal artery, a branch of the internal iliac artery. It gives rise to the penile (or clitoral) branch and the superficial perineal artery. The superficial perineal artery divides into medial and lateral branches and continues into its terminal branches, the posterior scrotal (or labial) artery. There is also a rich supra-aponeurotic vascular plexus supplying the labia majora in women and scrotum in men and surrounding perineal skin and soft tissue.

Reconstruction of the perineum can be complicated by prior surgeries and incisions, absent or inadequate musculature, impaired wound healing from radiation therapy, or from altered bloody supply. Factors such as smoking, diabetes, immunosuppression, atherosclerosis, prior surgeries, or advanced age are taken into consideration to avoid errors in flap selection and to maximize the outcome of the reconstruction.

GENERAL PRINCIPLES

Etiology of Defects

Perineal reconstruction may be indicated for congenital or acquired defects. Congenital perineal defects result from Müllerian or Wolffian aplasia, producing urogenital disorders such as imperforate anus, bladder exstrophy, and vaginal agenesis or atresia. Acquired perineal defects most commonly occur following surgical excision of primary or recurrent colorectal, gynecologic, or urologic malignancies. In this setting, perineal reconstruction frequently requires concomitant pelvic reconstruction by transferring well-vascularized tissue of sufficient bulk. Other less common causes of perineal and genital defects include traumatic injuries and infectious processes. Fournier’s gangrene is a rare but potentially fatal necrotizing fasciitis of the perineum and abdominal wall, along with the scrotum and penis in men and the vulva in women. Fournier’s gangrene is a surgical emergency. Skin loss can be incapacitating, difficult to repair, and may involve a combination of several techniques to achieve wound closure.

Preoperative Assessment and Surgical Planning

The preoperative evaluation of patients with present or expected perineal defects includes a comprehensive assessment of the patient’s comorbidities and the degree and nature of the anticipated perineal wound. Communication with the ablative surgeon is essential in case adjuvant therapies are planned that may influence the surgical plan. The anticipated defect of the external genitalia, the perineal skin, and, in the female patient, the vagina is evaluated. If partial or total perineal proctectomy is performed with the surrounding skin, it is essential to anticipate the amount of skin that will be removed. If a pelvic exenteration is planned, vascularization of the pelvic floor musculature may be disrupted. If a cystectomy is planned, preoperative discussion with the urologist for planning an ileal conduit is essential.

RECONSTRUCTION OF THE PERINEUM

Perineal reconstruction will ideally result in a healed wound in a single-stage procedure, with restoration of normal or near-normal function and minimal associated morbidity. Reconstruction is usually performed with local or regional flaps from the lower extremity and abdomen, and rarely requires free tissue transfer. Extensive perineal defects may require reconstruction with a combination of flaps. A useful start is the reconstructive ladder, which organizes options by complexity.

Small defects of the perineum can frequently be closed primarily. Moderate-sized, superficial defects are amenable to closure with either healing by secondary intention, skin grafting, or local skin flaps such as a rhomboid flap. Local surveillance in diseases with high recurrence rates, such as Bowen’s disease, may be easier following skin grafting. Skin grafting and local flap techniques may be suboptimal in the setting of urinary or fecal contamination, or with locally irradiated tissues. Regional flaps may be more ideal. Large superficial defects of the perineum (Figure 96.1) may best be downsized by negative pressure wound therapy, followed by flap or skin graft coverage. Large defects following abdominoperineal resections or total pelvic exenterations typically require immediate placement of a vascularized flap into the pelvis and perineum. Non-reconstructed pelvic cavities may become filled with fluid and/or intestinal loops, increasing the risk of prolonged wound drainage, pelvic abscess, perineal wound dehiscence, or bowel obstruction and herniation. The transfer of well-vascularized flaps to the perineum allows wound closure without tension, promotes primary wound healing, decreases postoperative complications, and requires fewer stages. Communication with the oncologic surgeon is essential when designing skin incisions and planning the location of stomas to preserve potential flap donor sites.

Decisions regarding flap selection include the amount of soft tissue needed, the adequacy of local blood supply, the presence of surgical scars at the donor site, patient positioning during surgery, as well as the operative approach used (i.e., laparotomy versus perineal approach). In men, the pelvis is longer and deeper than in women, so this additional length should be factored into the flap design.

FIGURE 96.1. A. A 24-year-old male with significant perineum tissue necrosis following infiltration of vasopressors into his left femoral venous catheter. B. After debridement of necrotic tissue. C. A wound vacuum-assisted closure was placed following debridement. D.One month after Split-thickness skin graft. Courtesy of Brian T. Carlsen, M.D.

The vertical rectus abdominis myocutaneous (VRAM) flap, delivered to the perineum through an intraperitoneal transpelvic route, is a workhorse flap for combined pelvic and perineal defects.1 The VRAM flap is based on the inferior epigastric vessels and can be harvested with or without a skin paddle, depending on the characteristics of the perineal defect. As a myocutaneous flap, it provides a robust skin paddle to the perineum, has a reliable vascular supply, and allows transfer of a large volume of soft tissue to obliterate the pelvic cavity created by tumor excision.2,3 It is extremely versatile, as it can be used for pelvic reconstruction alone, as well as for reconstruction of defects of the anterior or posterior vaginal wall, or for total vaginal reconstruction. In addition to the vertical skin paddle design, transverse and large oblique extended skin paddles have been described for tissue coverage or obliteration of dead space.4 Important considerations include: (1) when the flap is transposed into the pelvis, care must be made to prevent twisting or kinking of the pedicle; (2) the VRAM myocutaneous flap skin paddle may be unreliable in obese patients with thick subcutaneous fat. When compared with thigh flaps, the VRAM flap following abdominoperineal resection and pelvic exenteration is associated with fewer major postoperative complications.5

The pedicled greater omental flap is another available option for reconstruction of the pelvic floor when a patient has undergone a laparotomy. This flap is based on the right or left gastroepiploic vessels and is useful in patients with a narrow pelvis, in obese patients, or when the VRAM flap is unavailable. The greater omental flap is sometimes unavailable for reconstruction due to insufficient size, presence of adhesions, or previous surgical removal. Once the greater omentum has been dissected off the transverse mesocolon and the greater curvature of stomach, it can be passed to the right or left midline to bring vascularized tissue into a previously irradiated pelvis. This improves pelvic lymphatic drainage and decreases the risk of perineal hernia and bowel obstruction. The pedicled greater omental flap can also be covered with a skin graft for vaginal reconstruction.6

The gracilis flap is another useful flap for reconstruction of the perineum, due to its versatility and minimal donor site morbidity. Furthermore, it often lies outside of the radiation field and does not require a laparotomy. However, it has a short pedicle and unreliable skin paddle, which can limit its use for coverage of large defects. A skin paddle can be designed over the proximal and middle third of the muscle. The major pedicle, the ascending branch of the medial circumflex femoral vessels, is identified as it courses deep to the adductor longus muscle. During flap harvest, the distal tendon is divided and the muscle is dissected from distal to proximal, dividing any perforating vessels. Extended dissection to the profunda femoris artery provides additional pedicle length. The flap can then be tunneled into the defect or used as a free flap (Figure 96.2).

The posterior thigh flap can be useful when the rectus abdominis myocutaneous flap or the gracilis myocutaneous flap is unavailable. Based on the inferior gluteal artery, the posterior thigh flap is designed over the central aspect of the posterior thigh. Patency of the internal iliac vessels is confirmed prior to flap harvest as the inferior gluteal artery is a terminal branch. The posterior femoral cutaneous nerve innervates the skin of the posterior thigh. The flap is marked over the central axis of the neurovascular pedicle, which exits at the level of the gluteal crease midway between the greater trochanter and the ischial tuberosity. This flap can be raised with a patient in the lithotomy position, and the donor site may be closed primarily or skin grafted. If needed, a large amount of skin can be harvested, up to 34 cm × 15 cm. However, to provide sufficient bulk to obliterate large pelvic defects, this flap may need to be raised bilaterally7 (Figure 96.3).

The Singapore flap (pudendal thigh flap) is a versatile fasciocutaneous flap often selected for vaginal reconstruction.8 It is an axial pattern, sensate flap based on the superficial perineal artery. The pudendal nerve and the posterior cutaneous nerve of the thigh provide flap innervation. Depending on the type of perineal defect, the Singapore flap can be designed as a V-Y fasciocutaneous flap, or as bilateral flaps sewn together to form a neovagina.8

Other potential flaps for perineal reconstruction include the gluteal flap, as well as fasciocutaneous flaps such as the medial thigh flap, or perforator flaps. Perforator flaps such as the pedicled anterolateral thigh (ALT) flap, deep inferior epigastric perforator flap, and superior gluteal artery perforator flap have been used successfully to reconstruct perineal defects.9

FUNCTIONAL RESTORATION OF THE FEMALE PATIENT

The vagina is a cylindrical, muscle-walled structure extending from the vestibule to the uterus. It measures approximately 6 to 7.5 cm along its anterior wall and 9 cm along its posterior wall. It is in close relationship with the fundus of the bladder anteriorly and with the rectum posteriorly. Vaginal defects result from congenital or acquired causes. The goals of vaginal reconstruction include primary wound healing, decreased pelvic dead space, restoration of the pelvic floor, and the ability to have sexual intercourse.

FIGURE 96.2. A 26-year-old female with Crohn’s disease, status post abdominoperineal resection. A. Chronic perineal wound. B. Gracilis muscle flap. C. One-month postoperative result. Courtesy of Molly F. Walsh, D.O.

FIGURE 96.3. Pressure sore involving the perineum. A. Preoperative appearance B. Repair using bilateral V-Y posterior thigh advancement flaps and right gluteal rotation flap. Courtesy of Craig H. Johnson, M.D.

Congenital Vaginal Defects

Congenital vaginal agenesis or atresia is frequently associated with Mayer-Rokitansky-Küster-Hauser syndrome. This syndrome has an estimated incidence of 1 in 4,500 female births and is characterized by Müllerian ductal aplasia. Patients with congenital absence of the vagina typically present with normal development of secondary sexual characteristics and normal external genitalia. Associated deformities of the urinary tract and skeletal system are common. Other etiologies of congenital vaginal defects are those associated with disorders such as gender dysmorphia, bladder exstrophy, and imperforate anus.

Correction of vaginal agenesis can be accomplished with nonsurgical or surgical techniques. The Frank method is a nonsurgical approach that involves tissue expansion of the vaginal pouch, using vaginal dilators to progressively lengthen the vagina. It is a painful method with low compliance and high failure rates among young women. A number of surgical techniques are available. The most popular is the Abbe-McIndoe operation involving split-thickness skin grafts that are molded over a vaginal stent after dissection of a space between the bladder and the rectum. Other available surgical techniques include intestinal colpoplasty (e.g., sigmoid colon flap and jejunal flap) and the modified Singapore flap. When abdominal or perineal donor sites are unavailable following previous operative procedures in patients with associated congenital abnormalities, the gracilis flap or the posterior thigh flap can be used.

Acquired Vaginal Defects

Acquired vaginal defects can be partial or complete and most commonly result from surgical treatment of pelvic (i.e., colorectal, gynecologic, or urologic) malignancies. Other less frequent causes of acquired vaginal defects include obstetric and non-obstetric trauma, infectious processes, and burns.

Small vaginal defects may be closed primarily. Since regional flaps are usually available, larger vaginal defects rarely require free tissue transfers. Cordeiro et al.10 have described a useful classification scheme for acquired vaginal defects, based on the anatomic location. According to this classification, partial vaginal defects (type I) are separated into two subtypes. Type IA partial defects involve the anterior and/or lateral vaginal wall and typically occur following resection of urinary tract or primary vaginal wall malignancies. The ideal flap for reconstruction of this type of defect is the unilateral or bilateral modified Singapore fasciocutaneous flap. Type IB partial defects are the most common: they are primarily encountered with colorectal carcinomas extending to the posterior vaginal wall. The pedicled VRAM flap is ideal for reconstruction of type IB defects because of its great soft tissue bulk (Figure 96.4).

Circumferential vaginal defects (type II) are also divided into two subtypes. Type IIA vaginal defects involve the upper two thirds of the vagina, following surgical treatment of uterine and cervical diseases. They can usually be reconstructed with a rolled pedicled rectus myocutaneous flap. If the abdominal donor site is unavailable, an intestinal colpoplasty is another alternative. Type IIB defects are total vaginal defects generally resulting from pelvic exenteration, and reconstruction can be achieved with bilateral gracilis myocutaneous flaps.

FIGURE 96.4. A 42-year-old female with recurrent anal cancer and rectovaginal fistula. A. Defect following resection, including the posterior and lateral walls of the vagina. B. A vertical rectus abdominis myocutaneous (VRAM) flap inset into the defect. C and D. Two-month postoperative result, anterior and posterior view. E. VRAM donor site closure, 2-month postoperative result. Courtesy of Molly F. Walsh, D.O.

Surgical planning of vaginal reconstruction should take into account the need to restore sexual function. Elderly patients and patients with significant comorbidities may not require reconstruction of the vaginal vault. In this setting, a muscle-only VRAM flap can be used to fill the pelvic cavity. When there is concern regarding the viability of the VRAM flap skin paddle, bilateral modified Singapore flaps may be a better option for reconstruction of type IB defects. If a non-functional vaginal reconstruction is to be achieved, or in the presence of a type IIA defect, skin-grafted muscle flaps can also be used (e.g., rectus abdominis and gracilis).

Vulvar Defects

Vulvar reconstruction is generally required following surgical excision of tumors. Squamous cell carcinoma is the most common vulvar malignancy. Depending on the characteristics of the defect, various methods can be used for reconstruction, including primary closure, split-thickness skin grafts, or local flaps. Larger vulvar defects may require coverage with myocutaneous flaps from the medial thigh, abdomen, or posterior thigh.

FUNCTIONAL RESTORATION OF THE MALE PATIENT

Congenital deformities, trauma, infections, lymphatic malformations, and surgical treatment of malignancies are the most common causes of male perineal defects.11 Perineal tumor resection (e.g., squamous cell carcinoma of the penis, prostate cancer, and anal cancer) may require radical resection of soft tissue and subsequent radiation therapy, which can increase the risk of secondary complications such as perineal fistula and impaired wound healing.

FIGURE 96.5. A 24-year-old male with idiopathic scrotal and penile lymphedema. A. Preoperative appearance. B and C. After debulking of diseased penile and scrotal skin. D. After application of split-thickness skin graft harvested from the thigh. The scrotum was closed primarily. E. Foam dressing in place to keep the penis at full length. Courtesy of Craig Johnson, M.D.

Functional and aesthetic goals in reconstruction of the male patient are obviously different from those in female patients. Successful reconstruction of the penis takes into consideration the physiology of the phallus, including (1) a canal for urine and sperm; (2) erectile capability; (3) sufficient length; and (4) tactile and erogenous sensation.

Surface defects of the penis. Penile skin defects most commonly stem from congenital anomalies (e.g., bladder exstrophy), infections, trauma, circumcision complications, or oncologic resection. Surface deformities may also occur in obese males with a buried penis. Furthermore, idiopathic lymphedema and radiation-induced lymphedema of the penis may require therapeutic skin excision and cause surface defects.

Skin coverage can be achieved with various methods such as mobilization of redundant foreskin in uncircumcised patients, scrotal rotation flaps, and local flaps from the thigh or abdomen. These, however, are cosmetically inferior when compared with split-thickness skin grafts. Non-meshed split-thickness skin grafts (0.010 to 0.015 inch) are preferred (Figure 96.5). Intracavernosal injection to expand the phallus at maximal length may be helpful in applying the skin grafts. Foam dressing or negative pressure wound therapy can be a useful adjunct to promote successful skin graft healing. In order to avoid scar contracture and chordee, the suture lines between the graft edges should run obliquely.

Total Penile Reconstruction

Achieving satisfactory cosmetic and functional outcomes in total penile reconstruction is challenging and may involve several surgical procedures (Chapter 99). Phalloplasty in bladder exstrophy patients, in female-to-male transsexuals, as well as in post-traumatic reconstruction is now routinely performed using microsurgical techniques. Regional flaps (e.g., anterior lateral thigh flap) have been described for this purpose, but are associated with a higher incidence of urinary problems secondary to excessive flap thickness and technical difficulties with urethral reconstruction. The radial forearm free flap is the preferred method for total penile reconstruction.7 The lateral antebrachial cutaneous nerve can be harvested with the flap for subsequent neurorrhaphy with the dorsal nerve of the penis to provide sensory innervation to the neophallus.

Scrotal Reconstruction

Scrotal reconstruction may be required after extensive tissue loss, such as in the case of Fournier’s gangrene and subsequent debridements. Hyperbaric oxygen therapy may be considered as an adjunct to treatment, with a reported survival advantage. The scrotum is the area most often requiring reconstruction. Depending on the size of the defect, the scrotum can be closed primarily, with local skin flaps or with skin grafts (Figure 96.6). Defects up to 50% can be closed primarily, and tissue expansion has been described to achieve primary closure of defects up to 67%. For extensive wounds, the testes can be placed in thigh pouches until reconstruction, or can be managed with repeated wet dressing changes. It is important to keep in mind that long-term exposure to higher body temperatures in thigh pouches can hinder spermatogenesis. Meshed skin grafts are ideal for scrotal reconstruction as long as the tunica vaginalis is intact and are preferred as they allow exudate to escape, thus improving skin graft take. The testes will serve as natural tissue expanders, causing them to descend into an anatomical, dependent position over time. The spermatic cords should be sewn together before grafting to prevent a bifid neoscrotum. Skin grafts have the disadvantage of being insensate, and testicular torsion with vascular compromise in healed grafts has been known to occur. For extremely large scrotal defects, local flaps such as a pedicled VRAM flap, a pedicled ALT flap, or a sensate superomedial thigh fasciocutaneous flap may be considered.7

Penile Replantation

In the setting of penile amputation, replantation can be achieved at a facility with microsurgical capabilities. Although macroscopic anastamoses can be performed with good erectile function, there is a greater likelihood of skin loss, urethral strictures, and decreased sensation. Successful microsurgical replantation has been reported within 6 hours of warm ischemia or 16 hours of cold ischemia. The amputated penis should be rinsed in saline, preserved in saline-soaked gauze, sealed in a sterile plastic bag, and placed in a bag with crushed ice. The major steps for microvascular replantation are as follows: (1) two-layer urethral closure over a catheter with 5-0 absorbable sutures; (2) minimal dissection of the neurovascular bundle to identify vessels and nerves; (3) closure of the tunica albuginea with 3-0 absorbable sutures; (4) microsurgical anastomosis of the dorsal artery with 11-0 nylon and the dorsal vein with 9-0 nylon or a venous coupler; and (5) epineural repair of the dorsal nerve with 10-0 nylon. The patient should also receive a suprapubic cystostomy.12

FIGURE 96.6. A 57-year-old male with angiokeratomas of Fordyce. A. Preoperative appearance. B. After reconstruction of scrotum with bilateral local flaps and reconstruction of the penis with meshed split-thickness skin grafts. C. Recurrence of lymphedema of the scrotum and right lower extremity 10 years later. D and E. After scrotal reduction and primary closure. Courtesy of Philip G. Arnold, M.D. and Samir Mardini, M.D.

CONCLUSION

Reconstruction of the perineum remains challenging due to the complexity of surgical defects, the presence of irradiated wounds, and the need for functional restoration. The goal of reconstruction of the perineum is to achieve a healed wound in a one-stage reconstruction with minimal morbidity. A variety of reconstructive options are available. Close communication with the oncologic surgeons is essential for optimal flap selection and superior outcomes.

Suggested Readings

1.  Buchel EW, Finical S, Johnson C. Pelvic reconstruction using vertical rectus abdominis musculocutaneous flaps. Ann Plast Surg. 2004;52: 22-26.

2.  Butler CE, Rodriguez-Bigas MA. Pelvic reconstruction after abdominoperineal resection: is it worthwhile? Ann Surg Oncol. 2005;12:91-94.

3.  Chessin DB, Hartley J, Cohen AM, et al. Rectus flap reconstruction decreases perineal wound complications after pelvic chemoradiation and surgery: a cohort study. Ann Surg Oncol. 2005;12:104-110.

4.  Villa M, Saint-Cyr M, Wong C, et al. Extended vertical rectus abdominis myocutaneous flap for pelvic reconstruction: three-dimensional and four-dimensional computed tomography angiographic perfusion study and clinical outcome analysis. Plast Reconstr Surg. 2011;127: 200-209.

5.  Nelson RA, Butler CE. Surgical outcomes of VRAM versus thigh flaps for immediate reconstruction of pelvic and perineal cancer resection defects. Plast Reconstr Surg. 2009;123:175-183.

6.  Friedman J, Dinh T, Potochny J. Reconstruction of the perineum. Semin Surg Oncol. 2000;19:282-293.

7.  Friedman JD, Reece GR, Eldor L. The utility of the posterior thigh flap for complex pelvic and perineal reconstruction. Plast Reconstr Surg. 2010;126:146-155.

8.  Woods JE, Alter G, Meland B, et al. Experience with vaginal reconstruction utilizing the modified Singapore flap. Plast Reconstr Surg. 1992;90: 270-274.

9.  Sinna R, Qassemyar Q, Benhaim T, et al. Perforator flaps: a new option in perineal reconstruction. J Plast Reconstr Aesthet Surg. 2010;63: e766-e774.

10.  Cordeiro PG, Pusic AL, Disa JJ. A classification system and reconstructive algorithm for acquired vaginal defects. Plast Reconstr Surg. 2002;110: 1058-1065.

11.  Finical SJ, Arnold PG. Care of the degloved penis and scrotum: a 25-year experience. Plast Reconstr Surg. 1999;104:2074-2078.

12.  Campbell MF, Wein AJ, Kavoussi LR. Campbell-Walsh Urology. 9th ed. Philadelphia, PA: W.B. Saunders; 2007.