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Pelvic Exenteration


Pelvic Exenteration

Article Author:
W Grimes
Article Editor:
Michael Stratton
Updated:
10/12/2020 3:38:37 PM
For CME on this topic:
Pelvic Exenteration CME
PubMed Link:
Pelvic Exenteration

Introduction

The visceral components of the pelvis include gastrointestinal and genitourinary structures. The sigmoid colon, rectum, and anus are the terminus aspects of the intestinal tract. The genitourinary viscera include the urinary bladder and urethra; seminal vesicles and prostate (male); and uterus, ovaries, and vagina (females). Pelvic exenteration (PE) refers to an extended en bloc multi-visceral resection of pelvic structures.

A complete PE involves resection of the distal sigmoid colon, rectum, and anus along with the bladder, seminal vesicles, prostate, and urethra in males or the uterus, ovaries, vagina, bladder, and urethra in females. In females, partial pelvic exenterations can be performed as indicated: anterior- resection of the gynecologic and urologic structures with preservation of the rectum and anus; or posterior- resection of the gastrointestinal and gynecologic structures with preservation of the bladder and urethra.

PE was initially described in 1948 for palliative management of recurrent cervical carcinoma.[1] High surgical mortalities and poor survival outcomes in the 1940s and early 1950s limited the enthusiasm for these radical resections during the latter half of the 20th century. Medical advances involving anesthesia, transfusions, imaging, critical care, and surgical techniques have combined to allow PE to be performed with greater safety and improved outcomes.[2] In the 1950s and 1960s, the indications for PE were extended beyond palliative resections of cervical cancer. Indications included curative resections of locally advanced cancers involving contiguous structures, including rectal, ovarian, vulvar, prostate, and pelvic sarcomas and melanomas.[3] A nonmalignant indication for PE included radiation necrosis.[2]

Anatomy and Physiology

Embryologic studies by Hockel identified the pelvic urinary, genital, and digestive tract components to have a common origin in the ‘morphogenetic unit.’ The 3 units separate with their associated vascular supply, mesenteries, and lymphatic drainage. The rectum, anus, and mesorectum originate from the hindgut. The Mullerian morphogenetic unit forms the Fallopian tubes, mesosalpinx, uterine corpus and cervix, mesometrium, proximal vagina, and mesocolpium. The distal ureters, urinary bladder, urethra, and distal vagina arise from the urogenital sinus and Wolf ducts. Initially, these separate units provide a natural barrier for the extension of a neoplasm to adjacent structures. Current oncologic surgical guidelines identify the importance of removing the entire unit, including the meso-viscera. Per Hockel’s studies, radical compartmentalized surgery requires an en bloc resection of the unit with affected viscera. Removal of two or more morphogenetic units represents an ultra-radical compartmentalized surgery or pelvic exenteration.[4]

Current radical surgery expands the posterior compartment to include the sacrum with the rectum when necessary to achieve a complete (R0) resection. Likewise, an extension of an anterior compartment neoplasm might incorporate the pubic bone. The lateral extension of a pelvic neoplasm can require excision of the lateral compartment involving the vascular, neurologic, and muscular structures of the pelvic sidewall.

Indications

Symptoms related to advanced or recurrent pelvic malignancies include intractable pain, bleeding, sepsis, obstruction, and fistula formations. Some of the symptoms are also related to prior radiation therapy. The primary indication for PE is locally advanced carcinoma, both primary and recurrent. These lesions involve the contiguous pelvic organs or adjacent anatomy, including the pelvic sidewall, neurovascular structures, or boney components of the pelvis: sacrum or pubis. The goal is to achieve a complete oncologic (R0) resection indicated by the absence of malignancy involving the resection margins.[2] The intent of radical resection is to afford the patient a reasonable chance of cure, up to 63%.[2] The most important factor in predicting survival and quality of life for these advanced malignancies is an R0 resection.[5][6]

Historically, the triad of unilateral hydronephrosis, leg edema, and sciatic leg pain indicated pelvic sidewall disease that was unresectable. Extra-anatomic resections are now being performed with advanced preoperative planning utilizing pelvic MRI and/or CT angiograms or venograms with R0 rates of 66.5%.[7]

Contraindications

The primary contraindication for PE is the inability to achieve clear surgical margins free of malignancy (R0) in a well-informed patient. Because of the postoperative morbidity that may accompany PE, there is generally an unspoken consensus that exenteration should be offered only with resectable disease and with curative intent.[7] The palliative approach has not demonstrated improved quality of life but has modestly prolonged survival.[8] Though the role of PE for palliative intent is not well defined, some consider PE for uncontrolled fistulas, fungating tumors, and intractable pain to be reasonable exceptions.[9][10]

The appropriate role of PE in patients with metastatic disease is also unanswered. In general, PE should not be offered to patients who would not be candidates for adjuvant chemotherapy within conventional timeframes following PE due to the anticipated prolonged recovery interval.[7]

Preparation

Pelvic exenteration is a major multi-visceral operative procedure with significant risks of morbidity and mortality. Pre-operative evaluation of the patient should proceed with the gravity of the procedure as a guide.

For patients being considered for PE related to malignancy, histologic confirmation is imperative. The evaluation has two primary goals: confirm the absence of metastatic disease and assess the patient’s fitness to withstand an extended operative procedure with significant blood loss and fluid shifts.

CT scan of the chest, abdomen, and pelvis along with PET scan are instrumental in searching for possible metastatic lesions. Open or directed biopsies are necessary for pathologic review of any suspicious abnormalities. High-resolution pelvic MRI is valuable to define the local extension of the lesion to adjacent pelvic structures.[7] Along with the MRI, CT arteriography and venogram are often beneficial to plan the pelvic resection with a goal of achieving R0 margins.

Cystoscopy, vaginal examination, and lower GI endoscopy are usually necessary to establish a diagnosis and to determine the extent of pelvic visceral involvement.

Medical specialists play a key role in determining the patient’s cardiopulmonary reserve and optimization for pelvic exenteration. Potential extensive blood loss and fluid shifts, and surgical stress are to be anticipated. Anesthesia evaluation will determine the appropriate general and/or regional techniques to be employed. Adequate blood components should be secured and available. Along with the critical care physicians, the specialists' responsibilities will continue in the post-operative phase.

With a multi-visceral resection, multiple surgical teams are frequently required or should be on standby for all contingencies that can be anticipated. With a lead surgeon, a specific plan of surgery will be developed with the goal of completely resecting the lesion with R0 margins.

Once a surgical plan is finalized, the enterostomal therapist will need to educate and mark the patient for needed ostomies. Physical therapy should be involved with pre-conditioning and planning post-operative recovery.

Patients needing PE are frequently malnourished. Total parenteral nutrition might be indicated prior to surgery and continued with an anticipated delay for the return of adequate bowel function.

Patients undergoing pelvic exenteration are in a high-risk category for pulmonary embolism. Mechanical compression devices would be appropriate without increasing the risks of bleeding. Chemical prophylaxis should be individualized by the surgeons weighing the risks of intra-operative bleeding against the potential for a clinically significant pulmonary embolism.

Much attention is directed toward evaluating the patient's physical condition to tolerate PE. Clearly determining the potential for a curative resection is also central to the planning. The members of the caregiving team must also assess the patient's psychosocial inventory to whether pelvic exenteration with the anticipated prolonged recovery and image changes.

Technique

The patient is situated on the operating room table in a semi-lithotomy position (legs elevated and spread), most commonly with Allen stirrups, to allow prepped and draped access to the abdomen and perineum. Visualization of the pelvis is facilitated with a head-down (Trendelenburg) positioning of the operating room table. Surgical exploration is performed through a midline incision. A thorough exploration of the abdominal cavity, including the liver/spleen, gastrointestinal viscera, omentum, and peritoneal surfaces, is performed to exclude any metastasis beyond the anticipated extent of pelvic resection.

Dissection is initiated by incising the peritoneum overlying the iliac vessels and mobilizing the node bearing tissue medially to include with the specimen. The iliac branches to the specimen are ligated along with the Cardinal ligament in females. The peritoneum of the superior/anterior bladder is incised to mobilize the bladder posterior with the specimen. Each ureter is ligated proximal to the tumor and preserved for establishing urinary outflow. In males, the anterior dissection is carried to the pelvic floor, thus mobilizing the prostate, and the urethra is ligated. In females, the dissection is also carried to the pelvic floor and terminated at the urethra/vagina. Posterior, the inferior mesenteric pedicle is ligated at or above the aortic bifurcation. The sigmoid mesentery is divided, preserving the remaining blood supply, and the sigmoid colon is transected in preparation for a colostomy. The rectum is mobilized from the presacral fascia posterior, to assure a Total Mesorectal Excision, to beyond the tip of the coccyx. The dissection is continued bilaterally along the fascia of the pelvic sidewalls until the rectum and vagina/prostate are fully mobilized to the pelvic floor.

To complete the resection, the remaining perineal attachments are excised. An elliptical incision is made on each side of the anus, beginning just anterior to the coccyx. The anterior extent of the incision is carried across the perineum at the base of the scrotum or incorporating the vaginal introitus up to the clitoris. The soft tissues are divided down to the pelvic floor musculature. The pelvic floor is divided from the coccyx to the ischial tuberosities at the lateral extent and anterior to the urethral hiatus. The specimen, including the rectum, anus, vagina/prostate, and bladder, can be passed from the operative field as an en bloc resection.

Reconstruction is extensive. The pelvic floor defect can be closed with either a polypropylene mesh and covered with local soft tissue mobilization such as omentum, or the defect can be closed with a rectus abdominus myocutaneous flap. In some instances, gracilis myocutaneous flaps can be used for reconstruction of the floor or creation of a neovagina. Vaginal reconstruction is also performed with skin grafts or an isolated segment of the bowel.

For urinary outflow, a segment of vascularized ileum is isolated from the distal small bowel. Bowel continuity is restored with a proximal to distal segment enteroenterostomy. The ureters are implanted into the isolated segment of the ileum. The resulting ileal conduit (Bricker pouch) is matured via a right lower quadrant abdominal wall defect to the skin creating a urostomy. Currently, a continent urostomy has been popularized using the transverse colon and ileocecum. The transverse colon is fashioned as a pouch and the ureters are implanted. Either the residual terminal ileum or appendix is matured to the skin. The patient periodically catheterizes the stoma to evacuate urine. An additional advantage of the continent conduit is that the transverse colon is relatively spared from radiation effects reducing the risk of urinary fistulas.[11]

The reconstruction is completed by maturing the proximal sigmoid colon to the skin via a left lower quadrant abdominal wall defect.

For a partial or posterior PE in a female, the urinary structures are preserved. The uterus and vagina are mobilized from the bladder in the anterior plane. The anterior dissection is carried to the pelvic floor. The perineal excision preserves a cuff of the vagina at the urethral orifice to facilitate urinary outflow. For a partial or anterior PE in a female, the bladder and gynecologic structures are resected en bloc while preserving the rectum and anus. The perineal excision is carried out anterior to the anus with complete excision of the vaginal introitus.

For locally advanced tumors involving the pelvic sidewalls, the internal iliac artery and vein can be ligated and divided to gain access to the extra-fascial plane lateral to these structures.[12] The locally advanced disease might also necessitate resection of an involved sacrum or pubis.

Additional variations of PE involve the preservation of the pelvic floor. When adequate tumor margins can be obtained without resecting the pelvic floor musculature, the rectum and/or the vagina can be divided and closed above the pelvic floor. When the anal sphincter can be preserved, bowel continuity can be restored with either a low anterior or coloanal anastomosis with temporary diverting loop ileostomy for protection.

The complex multi-visceral and extended resections of PE are associated with prolonged operative times (5-14 hours) and substantial blood loss.[2]

Complications

Currently, morbidity related to PE ranges from 20% to 80%.[7] In a pooled study, the median in-hospital morbidity was 53.6%; the median hospital stay was 22 days (8 to 51 days), and the in-hospital mortality was 6.3% (0% to 66.7%).[3]

In the frequent context of preoperative radiation and redo surgery, urologic morbidity is high, in the range of 9%-24%, with urinary leak rates of 7% to 16%.[2] For patients having gastrointestinal anastomosis of all types, the anastomotic leak rate has been reported as 6%.[13] The leak rate for low anterior colon anastomoses is as high as 54%.[14] Pelvic abscess and enteric fistulas have been noted in up to 15% of patients with an empty, irradiated pelvis.[15] Techniques using the omentum to suspend the bowel and ileal conduit out of the pelvis or fill the pelvis have reduced the abscesses and fistulas.[16][17] Up to one-third of PE patients require further interventions to manage complications.[18]

To address the complications related to sepsis and malnutrition, policies to include 5 days of post-operative antibiotics and total parenteral nutrition until the return of gastrointestinal function have been adopted.[7]

Clinical Significance

Since the mid-1900s when the mortality for PE was around 23%, outcomes have improved to mortalities as low at 1-2% in specialized centers.[7] The most important factor for determining long-term survival following PE is achieving an R0 resection.[18] For patients with advanced primary or recurrent pelvic malignancies, surgical resection is the only intervention with the potential for cure. Across a variety of primary pathologies, three-year survival of 50% or greater was achieved with R0 resections. In appropriately selected patients, R0 resections can be achieved in approximately 70% of patients.[18] In a 30 year review, recent PE has been performed more for recurrent disease as opposed to primary tumor resections.[13]

The role of PE for advanced cervical, vaginal, and vulvar cancers has recently diminished related to improved responsiveness of primary malignancies to chemoradiation techniques.[11]

For palliative PE, the in-hospital mortality has been demonstrated to be 6.3% (0-66.7%) with an overall survival median of 14 months (4-40 months).[3] Due to high morbidity rates and limited overall survival, PE for palliative intent remains controversial. Evidence for symptom control and improved quality of life is also limited. Controversial quality of life evidence related to palliative PE is contrasted to patients having rapidly improved quality of life over 2-9 months following surgery for curative intent.[3]

Minimally invasive techniques are a developing aspect of PE. Studies have demonstrated that minimally invasive approaches are feasible for PE with less intra-operative blood loss and shorter length of hospital stay, but extensive reviews are not available.[19]

Enhancing Healthcare Team Outcomes

Specialized tertiary care centers that perform PE have been demonstrated to achieve improved long-term survival and surgical outcomes.[18]

Pelvic exenteration is a major surgical undertaking for the patient and surgical team. Specialized support is required from radiology, anesthesia, chronic pain specialists, oncologists, and critical care physicians. Allied health specialty support is needed for physical therapy and enterostomal therapy. To prepare for the prolonged recovery with home health or rehabilitation medicine, coordination with the hospital administration and social services is paramount. Physicians that perform pelvic exenterations either alone or as members of a team include general surgeons, oncologic surgeons, colon and rectal surgeons, gynecologists, gynecologic oncology surgeons, urologists, plastic surgeons, orthopedic surgeons, and neurosurgeons.

Pelvic exenteration is a complex operative procedure for patients with advanced primary or recurrent malignancies or complications related to the prior treatment for pelvic malignancies. These complex and varied procedures are individualized for each patient’s special needs. Thus, PE does not lend itself to standard controlled trials for the evaluation of management and outcomes. The PelvEx Collaborative has been established to provide a large volume of “real world” data that allow studies to improve outcomes related to exenterative surgery.[18] Over 100 international specialized units across five continents are contributing standardized data for ongoing studies. To date, the PelvEx Collaborative is responsible for eight publications.[20][21][22][23][24]


References

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[7] Koh CE,Solomon MJ,Brown KG,Austin K,Byrne CM,Lee P,Young JM, The Evolution of Pelvic Exenteration Practice at a Single Center: Lessons Learned from over 500 Cases. Diseases of the colon and rectum. 2017 Jun;     [PubMed PMID: 28481857]
[8] Quyn AJ,Solomon MJ,Lee PM,Badgery-Parker T,Masya LM,Young JM, Palliative Pelvic Exenteration: Clinical Outcomes and Quality of Life. Diseases of the colon and rectum. 2016 Nov;     [PubMed PMID: 27749474]
[9] Finlayson CA,Eisenberg BL, Palliative pelvic exenteration: patient selection and results. Oncology (Williston Park, N.Y.). 1996 Apr;     [PubMed PMID: 8723278]
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[14] Husain A,Curtin J,Brown C,Chi D,Hoskins W,Poynor E,Alektiar K,Barakat R, Continent urinary diversion and low-rectal anastomosis in patients undergoing exenterative procedures for recurrent gynecologic malignancies. Gynecologic oncology. 2000 Aug;     [PubMed PMID: 10926804]
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[20] Surgical and Survival Outcomes Following Pelvic Exenteration for Locally Advanced Primary Rectal Cancer: Results From an International Collaboration. Annals of surgery. 2019 Feb;     [PubMed PMID: 28938268]
[21] Factors affecting outcomes following pelvic exenteration for locally recurrent rectal cancer. The British journal of surgery. 2018 May;     [PubMed PMID: 29529336]
[22] Changing outcomes following pelvic exenteration for locally advanced and recurrent rectal cancer. BJS open. 2019 Aug;     [PubMed PMID: 31388644]
[23] Management strategies for patients with advanced rectal cancer and liver metastases using modified Delphi methodology: results from the PelvEx Collaborative. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland. 2020 Feb 11;     [PubMed PMID: 32043753]
[24] Simultaneous pelvic exenteration and liver resection for primary rectal cancer with synchronous liver metastases: results from the PelvEx Collaborative. Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland. 2020 Apr 15;     [PubMed PMID: 32294308]