Perineal Reconstruction

Perineal reconstruction may be divided into genitourinary reconstruction for acquired and congenital deformities and reconstruction for cancer. Reconstruction for congenital deformities is covered under the topic of urogenital reconstruction, while penile and vaginal reconstructions are covered separately in this journal. This article discusses perineal reconstruction related to cancer ablation in both male and female patients.[1]

The plastic surgeon encounters large defects in the perineal region most commonly in male patients following ablation of a recurrent low pelvic tumor. This is observed most often in concert with extensive irradiation of the pelvis. Preoperative consultation with the plastic surgeon is sought most often when the ablative surgeon is not confident that he or she can achieve a closed wound primarily. The oncologic team principally is concerned with separating the pelvic and abdominal cavities, protecting the small bowel from postoperative enteritis problems, preventing postoperative perineal herniation, and obtaining a healed wound primarily. Because this anatomic site is particularly prone to wound healing problems, the cancer surgeon often is concerned with bringing fresh, nonirradiated, vascularized tissue into the region.

Perform an overall nutritional assessment, including serum parameters, to determine the patient's suitability for large flap procedure. Assess the degree and nature of the expected perineal wound following cancer ablation; this can be performed most accurately in consultation with the cancer surgeon. In the female patient, this involves anticipated defect of the external genitalia, labia, minora, and majora; the extent of the perineal skin defect; and the extent of total or partial vaginectomy planned. If partial or total perineal proctectomy is performed with the surrounding skin, assess how much skin to remove. If cystectomy is planned or is possible, preoperative involvement of a urologist for planning ileal conduit is essential.

Perineal reconstruction is indicated when the anticipated defect is large and cannot be enclosed primarily. The following flaps may be considered in the preoperative evaluation of the patient:

• Gracilis myocutaneous flaps[2, 3, 4, 5]

• Rectus abdominis flaps[6, 7, 8, 9, 10, 11, 12]

• Posterior thigh flaps

• Groin flaps

• Pudendal fasciocutaneous flaps

• Gluteal (split) flaps[13]

• Rectus femoris flaps

• Tensor fascia lata flaps

• Vastus lateralis flaps

• Perforator flaps

  • Deep inferior epigastric perforator (DIEP) flap[14, 15]

  • Superior gluteal artery perforator (SGAP) flap[16]

  • Anterolateral thigh (ALT) flap

These flaps represent a partial, though not exhaustive, list of those that should be considered preoperatively. Assess whether stomas are to be created through the remaining rectus muscle and whether sacrifice may be contraindicated. Certain flaps may be favored because of positioning considerations; for example, the split gluteus myocutaneous flap can be performed with the patient in the prone position. If the defect is limited to the perianal region, these flaps are robust and may provide adequate closure. If the defect is anticipated to be superficial only, then a groin flap, pudendal flap, or posterior thigh flap may be preferred.

If significant dead space requires obliteration, a rectus abdominis myocutaneous flap based vertically (VRAM) or horizontally (TRAM) may be indicated. Lower extremity flaps (eg, tensor fascia lata, vastus lateralis, rectus femoris) may be preferred if abdominal or other donor sites are unavailable. In addition, a variety of other flaps are used less commonly but may be indicated in specific instances. These include the internal oblique muscle flap, omentum, medial or anterior thigh flaps, or superficial inferior epigastric artery flap.

The gracilis flap represents the "workhorse" for reconstruction of the perineal and pelvic defect.[17] In 1976, McCraw et al described the original reconstruction with the gracilis myocutaneous flap.[3]

The major blood supply to the gracilis myocutaneous or gracilis muscle flap is derived from the medial femoral circumflex artery. This artery enters the muscle approximately 8-10 cm below the inguinal ligament. Additional minor perforators originate proximally from the obturator artery and may supply a short gracilis flap. Occasionally one or two branches from the superficial femoral artery supplying the middle and distal portions of the muscle may be divided.

The nerve supply is the anterior branch of the obturator nerve, located between the adductor longus and magnus muscles. This nerve enters from deep to superficial, 1-2 cm superior to the major vascular pedicle from the medial femoral circumflex. When the adductor longus and magnus are retracted and the pedicle is dissected to the profundus femoris artery, its length ranges from 5-7 cm. This allows for more proximal positioning of the muscle pedicle.

The overlying skin paddle of the medial thigh may be elevated with the muscle. However, exercise care in elevating the skin territory distal on the medial thigh that has poor reliability. The skin island may be relocated more reliably proximally over the proximal two thirds of the muscle. Carefully elevate small musculocutaneous or septal perforators with the surrounding fascia over the sartorius laterally and the adductors medially to capture both the musculocutaneous perforators through the gracilis muscle as well as small septocutaneous perforators that may lie on either side of it.

Entertain the possibility of vascular disease in the lower extremity. Seek clinical assessment for claudication or other symptoms of vascular disease. Thorough examination of the peripheral pulses may indicate vascular disease, which may be a contraindication to gracilis reconstruction.

Obtain a full preoperative evaluation of the patient. This includes determination of the patient's history of the present illness with regard to status of the radiation dose and in particular, the radiation ports. Chronically indurated or erythematous tissue should be noted and potentially removed with ablation. Also explore chronic problems with fistula formation.

Gracilis flap[2, 3, 4, 5, 18, 19]

The operative technique for the gracilis flap is outlined below.

• Careful marking of the flap and skin island preoperatively is critical. This may be accomplished with the patient in the standing position and checked in the supine or lithotomy position.

• Assess the gracilis origin and insertion and draw a line from the pubic tubercle to the distal semitendinosus tendon.

• The skin paddle can be designed up to 10 cm wide, allowing a primary closure of the donor site.

• In general, accomplish the anterior incision first and raise the subcutaneous tissue as a flap anteriorly on the thigh. This allows for harvesting a larger portion of muscle fascia than that which directly underlies the skin paddle, capturing additional septocutaneous perforators. See image below.

  Perineal reconstruction. Bilateral gracilis myocutaneous flaps raised.

• As the fascia is elevated anteriorly, identify the gracilis tendon distally and confirm the location of the skin paddle directly over the proximal muscle by "bowstringing" the tendon. The saphenous vein remains anterior to the flap.

• With the dominant proximal pedicle exposed, ligate and divide the distal pedicles from the superficial femoral artery.

• Additional mobilization may be achieved by dissecting proximally to the profundus origin, dividing the branches that enter the adductor brevis and longus. This translocates the rotation point of the flap to approximately 7-8 cm below the pubic tubercle. Visualize and divide the obturator nerve.

• The muscle is not divided at its attachments to the pubic tubercle unless required for mobilization, thus providing a secondary blood supply through the proximal branches of the obturator vessels.

• The skin panel can be made into a complete island and tunneled into the perineum underneath the remaining perineal skin.

• Myocutaneous flaps can be rotated clockwise from the left thigh and counterclockwise from the contralateral thigh. Perform this with the patient in the lithotomy position with the hips adducted 45° and slightly flexed 15° while the knees are flexed slightly, taking pressure off the peroneal nerve. If these flaps are used to restore the pelvic cavity, they can be tubed to create a neovagina.

• For eliminating pelvic dead space, the flaps may be de-epithelialized as necessary.

• The image below depicts postoperative healing after application of bilateral gracilis flaps.

  Perineal reconstruction. Bilateral gracilis flaps for neovaginal reconstruction following postoperative healing.

Rectus abdominis flap[6, 7, 8, 9, 10, 11, 12]

The rectus abdominis flap, distally based in the deep inferior epigastric vessels, provides several distinct advantages over bilateral gracilis flap reconstruction. Its most obvious advantage is the robust skin paddle that can be de-epithelialized for bulk or tubed for neovaginal reconstruction. For large pelvic exenteration defects, the rectus abdominis muscle can be used alone or in combination with the de-epithelialized skin paddle. This flap is well perfused by the robust dominant pedicle and the deep inferior gastric artery and vein. In addition, this flap provides adequate muscle bulk to obliterate pelvic dead space (see image below). The skin island can be used for resurfacing the perineal region, including the vaginal wall, and provides versatility for all patterns of resection.[8, 20]

The operative technique for the rectus abdominis flap is outlined below.

• The cutaneous paddle can be designed in various ways along the epigastric region using the superior subcostal musculocutaneous perforators of the upper abdominal wall.

• The well-perfused region extends from below the costal margin to below the umbilicus and is approximately 20-25 cm long, directly overlying the rectus muscle.

• The skin paddle of 8-10 cm width usually can be closed primarily. However, if a larger paddle is desired, skin grafting usually is necessary and may be tenuous over the fascial closure. Alternative skin paddle designs to the longitudinally based pattern include a transverse orientation.

• If the pattern is to be de-epithelialized, this can be performed to resurface a large perineal defect. As the flap is elevated, the anterior fascia sacrifice remains somewhat narrower than the skin paddle. Thus, a strip of anterior rectus sheath, both lateral and medial, can be closed primarily.

• Detach the rectus muscle from its superior attachments to the lower costal margin and divide the superior epigastric vessels with cautery. The flap must be mobilized sufficiently by dividing the inferior intercostal perforators. See image below.

  Perineal reconstruction. This 70-year-old man with recurrent rectal cancer underwent a completion abdominal perineal resection and pelvic exenteration including resection of his bladder. The patient also had received external beam radiation therapy to the pelvis to help treat his cancer, making primary closure of the perineal skin unreliable. The operation left a very large defect in the perineal area including a large dead space in the pelvis. This was reconstructed using a pedicled vertical rectus abdominis myocutaneous flap (VRAM). This image shows the flap as it was elevated off the anterior abdominal wall. The flap is very well perfused and has sufficient bulk to fill the pelvic canal and obliterate the dead space. Courtesy of Wayne Stadelman, MD, Louisville, KY.

• After transposition into the perineal region through the pelvic defect (see image below), close the abdominal donor site. Use closed suction drains for both the donor and recipient sites.

  Perineal reconstruction. Flap inset into the perineal defect showing good vascularity. The patient recovered uneventfully and went on to complete healing without difficulty. Courtesy of Wayne Stadelman, MD, Louisville, KY.

In a study of patients who underwent abdominoperineal resection and neoadjuvant radiotherapy for rectal cancer, Touny et al found the perineal wound complication rate associated with the vertical rectus abdominis myocutaneous flap (VRAM) procedure for perineal reconstruction to be lower than that for primary perineal wound closure. In the prospective, randomized study of 60 patients with low rectal cancer, the investigators found that perineal wound complications occurred in 17.2% of patients who underwent VRAM and in 46.4% of patients treated with primary perineal wound closure, although surgical time and operative blood loss were lower in the latter group. The prevalence of abdominal wound morbidity was not significantly different between the two procedures.[21]

Deep inferior epigastric perforator flap

Although the deep inferior epigastric perforator (DIEP) flap has become well-established as an accepted technique for breast and trunk reconstruction, its use in the perineum as both a pedicled and free flap has become more common. An advantage of the DIEP flap over pedicled rectus myocutaneous techniques is significantly less abdominal wall morbidity.[15] However, this advantage may be outweighed by some considerations. First, the technical difficulties in flap harvest must be overcome by the steep learning curve with difficulties in flap venous insufficiency and perforator injury. Second, limitations in flap design with the DIEP flap make its use in perineal reconstruction more challenging than pedicled vertical rectus techniques.

Please refer to the perforator flap article in breast reconstruction for the technical details in flap harvest. In summary, the DIEP flap is designed as a horizontal skin island extending from the umbilicus to the suprapubic crease. Harvest includes no rectus abdominis muscle but a large segment of lower abdominal wall subcutaneous tissue, the Scarpa fascia, and the fatty layer below the Scarpa fascia. Once the tissue is freed to the level of the deep inferior epigastric vessels, the flap may be transposed into the pelvis without free tissue transfer; care should be taken not to kink or place tension on the pedicle.

Split gluteus maximus myocutaneous flap

While many variations of gluteus maximus flaps have been described,[22, 23] the split gluteal flap is particularly useful in resurfacing pelvic defects.[13] In this flap, only the superficial 1-1.5 cm of gluteal muscle is harvested, supplied by the proximal parasacral perforators. This allows elevation of the gluteal region primarily as a musculofascial cutaneous flap.

The operative technique for this flap is outlined below.

• With the patient in the prone jackknife position, mark the flap based proximally on the sacral border along the direction of the gluteus muscle fibers for an appropriate width to cover the defect.

• Elevate the flap from distal to proximal, splitting through the superficial 1-2 cm of the gluteus maximal muscle.

• Carry dissection proximally to within 1 cm of the sacral border while the deep portion of the muscle remains in situ. The inferior gluteal artery is protected, and the inferior gluteal and sciatic nerves are deep to the plane of dissection. Bilateral elevation of these flaps may be required if the dead space is substantial (see image below).

  Perineal reconstruction. Bilateral split gluteal flaps raised for obliteration of dead space. Note the myocutaneous flaps with gluteal musculature split longitudinally.

• The images below depict the original defect and postoperative healing.

  Perineal reconstruction. Complex postoncologic perineal defect following abdominoperineal resection with large dead space and anticipated postoperative irradiation (prone position).

  Perineal reconstruction. Flap inset with excellent healing postoperatively. Patient management similar to pressure sore protocol with air-fluidized mattress followed by early ambulation.

Gluteal thigh flap[24]

The gluteal thigh flap may provide a reliable, versatile reconstruction of perineal defects, with low donor site morbidity. This flap includes the inferior portion of the gluteus maximus muscle and encompasses the territory of the posterior thigh, directly supplied by the descending branch of the inferior gluteal artery.

The anatomy and technique for the gluteal thigh flap are outlined below.

• The design of the flap is centered on the descending branch of the inferior gluteal artery. Outline the flap on the central axis of the posterior thigh, perpendicular to the gluteal crease, with the rotation point 5 cm above the ischial tuberosity. It extends to 5-7 cm above the popliteal fascia.

• As the flap is elevated, divide the fascia lata and elevate the fascia overlying the hamstring musculature along with the posterior cutaneous nerve of the thigh.

• Ligate deep perforators as dissection proceeds proximally and elevate the inferior portion of the gluteus maximus muscle, with the flap up to the lower border of the piriformis muscle. The flap may remain sensate and provides excellent cover for the perineal region. It may be de-epithelialized in its distal portion and tubed for distal vaginal reconstruction.

• A disadvantage includes a "dog ear" formation at the medial rotation point, which may require secondary revision.

Perineal turnover perforator flap

A study by Chasapi et al indicated that a perineal turnover perforator (PTO) flap—that is, a perforator, islanded, turnover, de-epithelialized, local flap—can successfully be used in perineal reconstruction following extralevator abdominoperineal excision (ELAPE). Performed in cases of locally advanced low rectal cancer, ELAPE results in a larger perineal cavity than does standard abdominoperineal excision and has been tied to a high rate of perineal wound morbidity. The PTO flap, which is based on perforators from the internal pudendal artery, utilizes thick gluteal dermis to replace excised pelvic floor muscles and employs subcutaneous tissue to obliterate dead space. Evaluating 14 patients who underwent reconstruction with a PTO flap, Chasapi and colleagues found no flap, donor site, or major wound complications, although superficial skin dehiscence occurred in one patient, and perineal hernia developed in another. There were no instances of chronic perineal pain.[25]

Regional fasciocutaneous flaps

The use of fasciocutaneous flaps in perineal reconstruction is well described and the vascular anatomy of the perineal region is quite distinct. The super-fascial plane contains 3-5 segmental musculocutaneous perforators from the superficial vascular plexus. Venous drainage is by way of vena comitantes, thus a proximally based fascial cutaneous thigh flap can be designed with the flap base located approximately 5 cm from the perineum to preserve proximal vascular supply. This allows for primary closure of the donor site. The anterolateral thigh perforator (ATP) flap has enjoyed recent success in perineal reconstruction. Pedicled ATP island flaps can be used for reconstructing perineal defects up to 20 cm in size. Although the vascular anatomy is quite variable, it is well-described as a septocutaneous or musculocutaneous perforator.[26]

Subcutaneous and musculocutaneous perforators differ from the gracilis musculocutaneous flap. When the defect is superficial and dead space obliteration is not required, these may be appropriate flaps for perineal reconstruction. However, in the irradiated field or if postoperative radiation is planned, use caution in the design of these regional flaps.

A common complication is ischemia of the overlying skin paddle, resulting in delayed healing or partial or complete skin paddle loss. This often is related to an imprecise location of the skin island territory over the gracilis muscle or failure to include perforators to the overlying skin. The skin paddle can be positioned accurately by carefully marking the patient prior to induction of anesthesia in a standing position, drawing a line from the pubic tubercle to the distal semitendinosus tendon. This outlines the anterior border of the skin paddle and the gracilis muscle. With the patient anesthetized and in the lithotomy position, posterior displacement of the skin paddle occurs due to gravity, allowing for inaccurate marking and malposition of the flap skin territory.

Another common mistake is to inadequately harvest the septocutaneous perforators with the elevation of the muscle, causing ischemia of the overlying skin paddle. This may be prevented by dissecting the fascia widely on either side of the narrow gracilis muscle, including additional perforators with the flap. The muscle still may be used if the skin paddle is not perfused.

Gracilis myocutaneous reconstruction of perineal defects has the added advantages of reliability and long-standing use. Since its original description by McCraw,[3] it has proved to be a time-honored workhorse for perineal reconstruction. Functional donor site morbidity is minimal, with the other thigh adductors serving to take over muscular function. In addition, the bulk of these flaps provides soft tissue fill where required. However, the bulk may limit the aesthetics of the reconstruction if the defect is more superficial.

The rectus abdominis flap provides several advantages over bilateral gracilis flap reconstruction. The robust skin paddle can be de-epithelialized for bulk or tubed for neovaginal reconstruction. This flap is well perfused by the deep inferior gastric artery and provides adequate muscle bulk to obliterate dead space. The skin island is versatile both for resurfacing the perineal region and for reconstructing the vaginal vault.

The split gluteus maximus myocutaneous flap and the gluteal thigh flap are particularly useful in resurfacing pelvic defects. They both provide a reliable, versatile reconstruction of perineal defects with low donor site morbidity. In addition, the gluteal thigh flap may remain sensate when taken with the posterior thigh sensory branch and may be de-epithelialized and tubed for distal vaginal reconstruction. "Dog ear" formation remains a problem at the medial rotation point and may require secondary revision.

Regional fasciocutaneous flaps remain useful in perineal reconstruction when the defect is superficial. When dead space obliteration is not required, they may provide a more cosmetic contour than musculocutaneous flaps. However, use caution in the irradiated field or if postoperative radiation is planned.

A study by Wang et al indicated that in patients undergoing abdominoperineal resection or pelvic exenteration for anorectal cancer, immediate flap reconstruction of the perineum carries a lower risk than primary wound closure of a subsequent chronic draining wound. However, flap reconstruction was also associated with a higher rate of local infectious complications, although the investigators attributed this to a greater incidence of comorbidities in the group of study patients chosen for the flap procedure.[27]

A study by Pai et al indicated that following extralevator abdominoperineal excision (ELAPE) for low rectal cancer, immediate reconstruction with an inferior gluteal artery perforator flap is associated with good outcomes. The investigators found that 66.6% of patients were satisfied with the surgery’s aesthetic results. At 1-year follow-up, patient satisfaction regarding tolerance to sitting and perineal pain was 77.7% and 40.74%, respectively. The rate of perineal complications, major and minor, occurring within the first 30 days post surgery were 25.9% and 14.8%, respectively. The perineal hernia rate was, at 6-12 months, 14.8%.[28]

A study by Seo et al indicated that in vascularized free flap reconstruction of soft tissue defects of the perineal or inguinal regions, acceptable flap survival can be achieved by using a perforator artery as the recipient artery. The study involved 13 patients, with no instances of flap necrosis, arterial insufficiency, venous congestion, or infection.[29]