Introduction

Perineal reconstruction poses the challenge of healing a problem area, despite a number of site-specific obstacles. Although a number of benign conditions exist which can require resurfacing perineal skin, more frequently reconstruction is needed after treatment of underlying cancer. Modern treatment of malignancies in this region has evolved to consistently use neoadjuvant radiation therapy, which can yield a high rate of complications at the time of surgical intervention. Local effects of radiation therapy and close proximity (combined in many cases with ostomies) to bowels and bladder, can all impact the perfusion to reconstructive flaps, contaminate the surgical site, and threaten surgical outcomes. Successful reconstruction takes into account these impediments and minimizes the consequences of complications in this hazardous region.

History of perineal reconstruction

The evolution of perineal reconstruction over the last century parallels the development of the reconstructive ladder. Since Miles described abdomino-perineal resection in 1910 for carcinoma of the rectum, numerous methods of reconstructing the perineum have been described. In his original paper, the perineal wound was simply packed with gauze, with closure by secondary intention or delayed primary closure.¹ This led to significant morbidity associated with an open perineal wound, and Altmeier et al. subsequently introduced the concept of primary closure of the perineal wound with continuous suction drainage.² Although there was some degree of success with both primary and secondary closure of the perineum, certain perineal wounds seemed predisposed to breakdown, particularly those that were irradiated and contaminated. Brunschwig’s introduction of pelvic exenteration provided the potential for oncologic cure, but left an even larger pelvic defect with significant associated morbidity.³ Management of the draining perineal wound proved difficult; split thickness skin grafts were attempted with limited success.⁴

The advent of axial-pattern flaps ushered in the next rung on the reconstructive ladder for perineal reconstruction. Although first applied in coverage of exposed bone in the lower extremity, muscle flaps were soon utilized throughout the body, including the perineum.⁵ The gluteus maximus flap was described as a potential cure for a chronic perineal sinus.⁶ The rectus abdominus flap subsequently emerged to be a workhorse in perineal reconstruction.^7,⁸ Transverse, vertical and oblique skin paddles have been designed and used effectively. The gracilis muscle has also been described extensively for use in the perineum.^9,¹⁰

More recently, fasciocutaneous flaps have been reported for perineal reconstruction. Wee introduced the concept of neuro-pudendal thigh flaps for vaginal reconstruction, creating sensate lining for the vaginal wall.¹¹ The anterolateral thigh flap has emerged as a versatile flap that can be applied to perineal reconstruction as well as complex pelvic wounds.^12,¹³

Finally, advances in microsurgery have allowed free flaps to be performed routinely with reliable results. Although the utility of free flaps in perineal reconstruction has been somewhat limited by the ample loco-regional flaps available, there have been reports of free flaps for coverage of large defects in the perineal area, particularly in conjunction with sacral defects.¹⁴ Moreover, microsurgical techniques developed over the last decade have allowed perforator flaps to be applied to this region of the body as well. Both inferior and superior gluteal artery perforator flaps have been utilized for perineal coverage.¹⁵

Basic science/disease process

The processes requiring reconstruction of the perineum can broadly be broken into benign and malignant processes (Table 17.1). Benign conditions primarily include hidradenitis suppurativa, infectious destructive processes such as fasciitis or Fournier’s gangrene and trauma, but can range to other rarer dermatologic conditions such as pyoderma gangrenosum and vasculitic ulcers. These entities have in common the depth of involvement, which typically leaves an external cutaneous deficit on the perineum (see Figs 9.13, 9.18). Once the primary process is addressed and resolving, the defect can begin secondary healing, although negative pressure therapy and skin grafts can often play a useful role in shortening the time to healing.

Table 17.1 Benign and malignant processes requiring reconstruction of the perineum

Malignant diseases include colorectal cancer, urologic and gynecologic cancers, which originate from and involve deeper structures (see Figs 9.11, 9.12). Abdominoperineal resection or exenteration has been demonstrated to provide the best cure in these cases. Typically, this extensive resection is accompanied by peri-operative radiation therapy. Treatment of these more complex defects must be individualized for the missing and exposed structures. Impediments to healing such as fistulas and radiation changes in the area generally mean these defects will not heal without the addition of a nonradiated tissue transfer. Large areas of dead space after extensive resection can allow the abdominal viscera to fall into the irradiated pelvic basin. This can lead to adhesions, obstruction, and fistulas, which can be disastrous to treat secondarily. Nearby organs such as the bladder or vagina may also be resected in part or whole as part of the treatment course.

Diagnosis/patient presentation

Patients with benign disease may present at various stages in their treatment. As a rule, reconstruction should not be initiated until the primary process is identified and resolved with repeated surgical debridements or excisions; underlying medical conditions or autoimmune disorders should be treated. Typically, areas of external perineal skin are involved and will require resurfacing in some fashion (Fig. 17.1).

Fig. 17.1 Perineal hidradenitis.

Patients with malignant disease are typically treated in conjunction with a multidisciplinary oncologic team. Often the extent of the defect is not obvious until after the surgical resection is performed. Preoperative consultation is important to manage patient expectations, outline the possible extent of surgery and prepare for postoperative adversity. Such cases may involve more extensive external pudendal defects (Figs 17.2, 17.3) or deeper structures (Fig. 17.4). In the event that vaginal resection is necessary, preferences regarding vaginal versus simple perineal reconstruction should be discussed, along with a thorough dialogue about sexual function. Further details and management of vaginal reconstruction is discussed in depth in Chapter 14.

Fig. 17.2 Post-radiation lymphangiosarcoma after treatment of vulvar cancer.

Fig. 17.3 External perineal skin and soft-tissue loss.

Fig. 17.4 Complex perineal defect involving external skin, soft-tissues, vagina and pelvic floor.

Patient selection

Patients with benign disease are more straightforward in management; as their underlying process resolves, the defect begins to heal secondarily, even in response to a conventional wet to moist dressing regimen. Typically a modest, shallow perineal defect is left. A number of publications support the use of a negative pressure therapy plan to accelerate the healing process. Within a matter of weeks, a healthy wound bed can be established, confirming the suitability of these patients for skin grafting. If the wound fails to begin the healing process despite wound healing optimization, a more complex approach and tissue transfer might be warranted.

In the case of malignancy, radiation therapy is part of the preoperative routine in most centers. This factor alone is the most significant indication for flap reconstruction at the time of resection. Large prospective series suggest that abdominal based flaps demonstrate the most favorable outcomes and mildest complication profile in this setting, even compared to thigh flap reconstruction.¹⁶ This must be balanced with the abdominal morbidity of the harvest. Some surgeons prefer to avoid using abdominal flaps if ostomies are necessary on both sides, although these can be inset through the external oblique musculature with no additional morbidity. A vertical skin pedicle provides the most discreet scar, but an oblique paddle can provide more bulk extending off the muscle, effectively extending its reach also. Preexisting abdominal wall defects might direct some surgeons to alternative flap options. Nevertheless, Butler has shown no increased incidence of abdominal wall problems after abdominal flap harvest.^16,¹⁷ Rarely, perineal resection can be performed without laparotomy and this might predispose toward use of a nonabdominal flap option.

The complication profile of the gracilis flap is also reasonable, and represents a dramatic improvement over primary closure under these circumstances. Early studies comparing gracilis reconstruction to primary closure demonstrate a dramatic reduction in infectious complications from 46% to 12% with flap reconstruction.¹⁸

The anterolateral thigh flap represents an alternative option with documented excellent reliability for many applications, but with less support for its use in this setting.

Some surgeons favor a posterior thigh flap, harvested in similar fashion to the anterolateral thigh flap, but the axial nature of the perfusion off the inferior gluteal artery has been called into question. Recent series document over a 50% wound healing complication rate using this method,¹⁹ which does not compare favorably to abdominal flaps.

For defects with less dead space or requiring less bulk, Singapore flap reconstruction can be used, although outcomes data are more mixed and overall less favorable compared with abdominal flaps. Complications are reported to range from 7% to 62%.²⁰^–²² Recent outcome studies are not available directly comparing this method to other options in head-to-head fashion.

Massive defects in pelvic support may in fact require multiple flaps. Occasionally pelvic floor support is needed in the form of mesh reinforcement. In a hostile, radiated, often contaminated surgical site, prosthetic mesh is contraindicated. Newer bioprosthetic options provide a reinforcement alternative that is more robust in the face of complications.²³

Finally, if the two abdominal flaps and eight thigh-based flaps are unavailable or insufficient for the defect, there are several reports of distant flaps used in conjunction with microsurgical transfer. Composite thigh tissues can be transferred en bloc, and large surface area flaps such as the latissimus dorsi have been reported in extreme cases.