Introduction
Pelvic exenteration is a complex surgical procedure with a high risk of complications. It includes the removal of organs and structures within the pelvis, like the reproductive organs, bladder, rectum, and some parts of the colon and small intestine. This intricate procedure is done to treat advanced forms of pelvic tumors, recurrent pelvic tumors, and tumors that have spread to multiple pelvic organs. It is also done in cases where other treatment options have failed or are ineffective.
Pelvic exenteration is reserved for cases where there is a reasonable chance of removing the tumor and a complete and potential cure for the affected condition. It is most frequently performed in gynecological cancers, including cervical, ovarian, or vaginal cancer. It is also done in prostate, colorectal, and bladder cancer. Pelvic exenteration is considered the last resort when other treatment options have failed.
What Is Pelvic Exenteration?
It was initially introduced as a palliative treatment for conditions like cervical carcinoma in the year 1948. Due to poor surgical outcomes and a high mortality rate in the early 1950s, this surgical procedure was not much appreciated. Due to medical advancements in surgical techniques, anesthesia, imaging, and critical care, pelvic exenteration became safer with improved outcomes. The scope for pelvic exenteration became wider after the 1950s, and it was not just limited to palliative care for cervical carcinoma but also for curative treatment for locally advanced cancers involving nearby structures like rectal, vulvar, ovarian, prostate, pelvis sarcoma, as well as melanomas. It is also used in non-malignant situations like radiation necrosis.
What Are the Types of Pelvic Exenteration?
The pelvic region consists of gastrointestinal and genitourinary structures such as the sigmoid colon, urinary bladder, rectum, urethra, anus, seminal vesicles, prostate, ovaries, uterus, and vagina. The procedure of pelvic exenteration involves the removal of multiple structures as a single unit.
1. Complete Pelvic Exenteration: A complete pelvic exenteration involves the removal of the distal sigmoid colon, urinary bladder, rectum, and anus. In males, along with it, the prostate, seminal vesicles, and urethra are removed. In females, along with it, the uterus, ovaries, and vagina are removed.
2. Partial Pelvic Exenteration: In certain instances, partial pelvic exenteration might be performed so as to preserve certain structures depending on individual patient factors and requirements.
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Anterior Partial Pelvic Exenteration: Anterior partial pelvic exenteration involves the removal of urologic and gynecologic structures, excluding the rectum and anus.
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Posterior Partial Pelvic Exenteration: In posterior partial pelvic exenteration, resection of gastrointestinal and gynecologic structures is done excluding the bladder and urethra.
How Is Pelvic Exenteration Done?
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Patients are positioned on the operating table with their legs spread and elevated. This position will help assess the abdomen and perineum.
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For better visualization of the pelvis, the operating table is tilted to a Trendelenberg position.
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A midline incision is done to initiate the surgical exploration. Through this incision, the abdominal cavity is explored.
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Exploration of organs, including gastrointestinal organs, spleen, liver, omentum, and the perineal surface, is important for ensuring that cancer has not spread beyond the expected extent of pelvic exenteration.
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The dissection process begins by making an incision in the peritoneum covering the iliac vessels, mobilizing the lymph nodes containing tissue medially. The iliac branches are ligated with the cardinal ligament in females.
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The peritoneum that covers the anterior or superior bladder is cut to move the bladder posteriorly with the specimen.
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Each ureter is ligated above the tumor but preserved for the purpose of maintaining urinary flow. In males, anterior dissection extends to the pelvic floor, which will mobilize the prostate gland and the urethra is ligated. In females also, the dissection reaches the pelvic floor ending at the vagina or urethra.
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The sigmoid mesentery is divided, preserving the blood vessels remaining, and the sigmoid colon is transected for a colostomy.
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Dissection will continue on both sides in the sidewalls along the fascia until the rectum and vagina (female) or prostate (male) completely mobilize to the pelvic floor.
How Is Reconstruction Done After a Pelvic Exenteration?
Reconstruction is considered a comprehensive approach, and the pelvic floor defect is closed using a propylene mesh which is then covered by locally mobilized soft tissue like rectus abdominis myocutaneous flap and omentum. Skin grafts or isolated bowel segments are used for the purpose of vaginal reconstruction. For the establishment of urine outflow, a section of vascularized ileum is isolated from the small bowel.
Bowel continuity is restored by the creation of an enteroenterostomy that connects the proximal segment to a distal portion of the bowel. Ureter is then implanted into the isolated ileal segment. This resulting structure is known as a Bricker pouch or ileal conduit. This pouch is brought out via the abdominal defect in the right lower quadrant, creating a urostomy. The transverse colon is shaped like a pouch for implanting the ureters. The remaining portion of the terminal ileum is brought out to the skin. This reconstruction is completed by bringing the proximal sigmoid colon out through the remaining abdominal wall defect in the lower quadrant to the skin.
What Are the Indications and Contraindications of Pelvic Exenteration?
The main indication for a pelvic exenteration is a locally advanced carcinoma, either primary or recurrent form of cancer. Symptoms caused by recurrent pelvic malignancies are intractable pain, sepsis, bleeding, fistula, and obstructions. The goal of the pelvic exenteration procedure is to indicate the absence of malignancy that involves resection margins.
Clear-cut contraindication of pelvic exenteration is when there is an inability to find a clear surgical margin that can be free of malignancy. As this procedure is the last resort, when patients have the possibility of recovery from adjuvant therapies, pelvic exenteration is contraindicated. Since the morbidity rate is significant in this procedure, it should be offered as a treatment protocol only when all other measures fail.
Conclusion
Pelvic exenteration is a complex surgical procedure involving multi-visceral organs and has significant comorbidities and risks associated with it. This has a substantial risk of complications and even death. It is important for a thorough preoperative examination to execute this procedure. It is also important for a histologic examination to be performed to confirm the absence of metastatic spread and assess the patient's overall health to endure that lengthy procedure that involves significant blood loss and fluid shifts.
