Background
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.
Presentation
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.
Indications
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:
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Posterior thigh flaps
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Groin flaps
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Pudendal fasciocutaneous flaps
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Gluteal (split) flaps [13]
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Rectus femoris flaps
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Tensor fascia lata flaps
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Vastus lateralis flaps
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]
Relevant Anatomy
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.
Contraindications
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.
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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.
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Perineal reconstruction. Demonstration of the perineal defect and large dead space to be obliterated. Courtesy of Wayne Stadelman, MD, Louisville, KY.
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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.
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Perineal reconstruction. Complex perineal defect following pelvic exenteration.
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Perineal reconstruction. Bilateral gracilis myocutaneous flaps raised.
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Perineal reconstruction. Bilateral gracilis flaps for neovaginal reconstruction following postoperative healing.
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Perineal reconstruction. Complex postoncologic perineal defect following abdominoperineal resection with large dead space and anticipated postoperative irradiation (prone position).
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Perineal reconstruction. Bilateral split gluteal flaps raised for obliteration of dead space. Note the myocutaneous flaps with gluteal musculature split longitudinally.
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Perineal reconstruction. Flap inset with excellent healing postoperatively. Patient management similar to pressure sore protocol with air-fluidized mattress followed by early ambulation.
