eMedicine Specialties > Plastic Surgery > Trunk

Perineal Reconstruction: Treatment

Author: Chet L Nastala, MD, Plastic, Reconstructive, and Microsurgical Associates of South Texas, PA
Contributor Information and Disclosures

Updated: Feb 27, 2009

Treatment

Preoperative Details

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.

Intraoperative Details

Gracilis Flap^1,2,3,4

Operative technique

• 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.
• 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.

Rectus Abdominis Flap^5,6,7,8,9,10

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. The skin island can be used for resurfacing the perineal region, including the vaginal wall, and provides versatility for all patterns of resection.⁷

Operative technique

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

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.¹³ 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.

Operative technique

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,^15,16 the split gluteal flap is particularly useful in resurfacing pelvic defects.¹¹ 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.

Operative technique

• 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.

Gluteal Thigh Flap¹⁷

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.

Anatomy and technique

• 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.

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.¹⁸

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.

Complications

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.

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