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Pelvic wall resection/pelvic exenteration of colorectal cancer


Medical editor Stein G. Larsen MD
Gastroenterological Surgeon
Oslo University Hospital
Norway

General

In some cases of primary cancer, and frequently in local recurrences, the pelvic wall is infiltrated. This may be due to direct invasion or metastases to lymph nodes on the pelvic wall. A pelvic wall resection may then be performed.

This commonly occurs simultaneously with infiltration of central pelvic organs. A pelvic exenteration is then performed.

Pelvic wall resection

The possibility of removing a tumor radically from the pelvic wall depends on what organs the tumor is close to by and how far into the structure the tumor is growing.

The possibility of a curative resection varies between zones in the pelvis.

Zone 1

Problems associated with walking occur with resection of a tumor on to the nerve roots to L5, S1, and S2 upwards/laterally/behind the pelvis. If the sciatic nerve localized below/laterally must be resected the patient will not be able to walk.

A total sacrectomy including the S1 vertebra causes prominent and long-term walking problems due to instability of the spine and nerve damage. This procedure is not recommendable in cases of malignancy.

Resection between S1/S2 vertebras with injury to S2 causes prominent walking problems.

Surgery in this zone is not recommended.

Zone 2

The iliac vessels at the pelvic entrance can in some cases be resected and replaced with a graft.

The sacrum can be resected between the S2/S3 vertebrae while conserving the S2 nerves. The lateral obturatora nerves cause prominent walking problems if damaged.

Surgery in this zone can be performed in otherwise healthy patients.

Zone 3

Resection above the S4 level causes bladder paralysis. Caudal/dorsal to the obturator muscle is the internal obturator muscle and levator ani which can be resected. Collateral veins leading into the pelvis in front of the foramen ischiadicum and veins coming directly from the frontal surface of the sacrum can cause serious bleeding and be potentially life-threatening.

Preoperative chemoradiation is administered to shrink the tumor if the patient has not obtained radiation to the pelvis previously. Hyperfractionated re-irradiation may also be indicated.

Surgery in this zone is frequently performed especially in local relapse. Palliative surgery is appropriate if the patient has a fistula or threatening fistula.

Pelvic exenteration

Pelvic exenteration involves removal of the central organs of the pelvis.

For rectal cancer, a total exenteration is performed when there is infiltration into the prostate/bladder in men. Posterior exenteration is performed when there is infiltration into the vagina/uterus in women. In women with previous hysterectomy the cancer can infiltrate the bladder requiring a total exenteration.

For gross infiltration in certain organs, the indication for pelvic exenteration is clear. However, there can be a therapeutic problem if the tumor grows close to an organ with uncertain infiltration. There is also the problem that in about 25% of the fixed tumors the adherence is  caused by pericancerous fibrosis and not cancer infiltration. For infiltration close to other organs, it is uncertain which distance is necessary from the tumor to the resection surface in order for the procedure to be radical. There is often simultaneous growth into the pelvic wall which must also be removed.

Total pelvic exenteration is rarely indicated for primary tumors  but more often local recurrence.

Preoperative chemoradiation is often administered to shrink the tumor if the patient has not been irradiated to the pelvis previously.

Palliative surgery may be appropriate for intestinal or urinary fistulas.

Indications

  • Locally advanced cancer and local relapse with infiltration into the pelvic wall/central pelvic organs,
  • Younger patients with radically resectable distant metastases.

Goals

  • Curation
  • Avoid large functional handicaps
  • Palliation of fistulas in patients with relatively long expected survival time

Equipment

  • Laparotomy tray
  • Stapling instruments: cross stapling/closing-dividing/circular
  • Ureter catheter
  • Operation table with adjustable leg supports

 


Preparation

  • Location of possible colostomy and urostomy is marked on the skin.
  • Bowel emptying is performed if anastomosis of the rectum is considered. For a pelvic exenteration this is not necessary.
  • Thrombosis prophylaxis 
  • Antibiotic prophylaxis is administered.
  • Epidural catheter inserted for postoperative pain treatment.
  • A bladder catheter is inserted.
  • The patient lies flat with their legs supported such that the legs can be lifted easily when surgery is performed on the perineum.
  • If the sacrum is to be resected from the dorsal side, the patient must be turned to the prone position during the procedure.
  • The operation is carried out under general anesthesia.

Implementation

The operation is carried out with a total mesorectal excision as the basic principle.  

Dissection for pelvic wall resection

In a pelvic wall resection, the autonomic nerves are identified on the pelvic wall. These must often be resected.

The relatively strong fascia of the vessels over the nerves must be mobilized if a tumor is located on the large nerves.

  • The peritoneum is divided over the external iliac vessels. These are followed dorsally in to the iliaca communis vessels.
  • The internal iliaca vessels and nerve fasciculi and the tumor's relation to these are identified.
  • In certain cases, the iliaca communis or external vessels can be resected and reconstructed.
  • The tumor is recessed with deeper fascia, muscle tissue, and possibly vessels and nerves.
  • The sacrum can, if possible, be recessed in continuity with the tumor from level S3/S4 by chiseling through the sacrum from the pelvic side. From level S2/S3 this should be done from the posterior after releasing the lower nerve roots and ligature of the dural sac.

Reconstruction of pelvic wall resection

  • When a large part of the pelvic floor and sacrum are removed, the pelvic floor can be reinforced with a musculo-cutaneous flap (VRAM). The skin on this is de-epithelialized and stitched to the lateral pelvic wall as a new pelvic floor as replacement for the lower part of the sacrum. If a rectum amputation is not performed, the skin over the VRAM flap is closed.
  • A vacuum drain is placed in the pelvis.
  • The abdomen is closed.

A gross pelvic wall resection may be carried out by a team including a rectal, orthopedic  and plastic surgeon, and possibly vascular surgeon.

Dissection for pelvic wall exenteration

The autonomic nerves on the pelvic wall do not need to be spared in a pelvic exenteration as the bladder and internal genitals are removed.

  • Bladder/prostate is released from behind the symphysis and the urethra is divided.
  • The bladder vessels are divided.
  • When the dissection is down to the pelvic floor from above, the further dissection is from the perineum as in a rectal amputation.

Reconstruction of pelvic exenteration

  • A bladder function is reconstructed with a segment of the small intestine (Bricker's method).
  • 20-25 cm of small intestine is isolated from the bowel continuity with conservation of the main vessels. The bowel continuity is restored. Both ureters are anastomosed to the oral end of the isolated bowel. The analendis brought forward as a stoma in the right rectus muscle.
  • Ureter catheters are brought from the renal pelvis out through the bowel bladder.
  • A sigmoideostomy is constructed in the left rectal muscle.
  • The perineum is sutured.
  • If a large part of the pelvic floor or entire posterior vaginal wall is removed, a musculo-cutaneous flap can be placed in the pelvis to reconstruct the vagina, improve healing, as well as reduce the danger for infection and hernia in the pelvic floor.
  • Vacuum drain is placed in the pelvis.
  • The abdomen is closed.

Pelvic exenteration may be performed in collaboration with – rectal surgeon, urologist, plastic surgeon, and possibly gynecologist.


Follow-up

  • The patient may drink and eat on the first postoperative day.
  • The patient may be mobilized as soon as possible. If the patient has a myocutaneous flap, the patient should stay in bed for one week and avoid lying in the supine position.
  • The drain is removed when there is no longer fresh blood, usually on the 2nd-3rd day. If a swing flap is made, the drain should be removed when the draining volume is less than 200 ml/day.
  • For pelvic wall resection:
    • The bladder catheter is kept until the bladder empties spontaneously to avoid a large bladder from putting pressure on the myocutaneous flap and reducing the circulation.
  • For pelvic exenteration:
    •  The ureter catheters through the Bricker bladder are removed after 10 days if the patient has received postoperative radiation. 
  • The epidural catheter is removed usually on the 2nd-3rd day and the patient obtains an oral analgesic.
  • The patient is usually discharged after 3 weeks.

Complications

  • Urinary tract infections - occur relatively frequently
  • Leakage of the urinary anastomosis
  • Necrosis of the musculocutaneous flap
  • Thrombosis/embolism
  • Cardio-pulmonary complications  

In a pelvic wall resection, bowel leakage and bleeding may occur postoperatively.

Pelvic wall resections can be complicated. Extensive sacral resections and pelvic exenterations have a postoperative mortality up to 5%. When operating for recurrent cancer especially, there may be adherences making the dissection more difficult.


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