Management of Intraoperative Vascular and Urinary Complications
Intraoperative Vascular Complications
The veins of the vertebral venous system are located both outside and inside the vertebral canal and extend the entire length of the vertebral column. The external vertebral system consists of anterior and posterior plexuses with the former lying in front of the vertebral bodies. The presacral venous plexus represents the most distal portion of the anterior external vertebral plexus and comprises the middle sacral, lateral sacral, and communicating veins.
The presacral venous plexus communicates with the terminal portion of the internal vertebral system via the sacral basivertebral veins that penetrate the boney surface of the anterior sacrum within foramina usually located in the bodies of S3-S5.The adventitia of these sacral basivertebral veins is blended with the sacral periosteum at the margin of the opening of the foramina. When the presacral fascia tissue is lifted during dissection, the basivertebral vein is potentially lacerated near the opening of the foramen it traverses and the transected end retracts into the foramen.
Presacral bleeding can originate from disruption of the presacral venous plexus or avulsion of the sacral basivertebral veins. The clinical consequences of either are worsened by three factors that can lead to massive bleeding, and they are as follows:
- The presacral venous plexus and sacral basivertebral veins are devoid of valves, and this allows bidirectional blood flow.
- Numerous veins connect the vertebral venous system with the inferior vena cava below the diaphragm.
- The lower sacrum is in a significantly more dependent position compared to the lumbar vertebrae in the lithotomy position.
The resultant bleeding from a transected presacral vein measuring 2- or 4-mm in diameter can reach >100 mL/minute or >1000 mL/minute, respectively.
The anatomy of the rectosacral fascia (Waldeyer’s Fascia) that runs from the fascia propria of the mesorectum to the presacral fascia at the level of S3/S4 also contributes to potential injury of the presacral veins. The insertion of the rectosacral fascia onto the periosteum corresponds to the level of the sacral basivertebral veins. Blunt disruption of the rectosacral fascia or non-anatomical dissection distal to the fascia can cause accidental laceration of the presacral veins with resultant bleeding.
Regardless whether the procedure is performed via an open or minimally-invasive approach, inadvertent instigation of massive presacral bleeding is best avoided by maintaining clear visual exposure and employing sharp dissection at and below the rectosacral (Waldeyer’s) fascia. Visualization of this most distal dissection is sometimes improved by performing the lateral and anterior mesolectal dissection first. The rectosacral fascia should be deliberately incised using a sharp instrument or cautery. The dissection then continues in a more anterior or ventral direction towards the levator hiatus as the curve of the distal sacrum and coccyx is followed.,
Patients with a locally advanced rectal carcinoma occasionally demonstrate tumor extension beyond the fascia propria of the posterior mesorectum. If the anterior periosteum appears involved, sacrectomy is usually planned and the vertebral venous system is controlled where the vertebral column is transected at the uninvolved interspace and after the specimen is delivered. Alternatively, less invasive disease can require excision of only the presacral fascia to obtain an R0 resection, and in these cases presacral bleeding cannot necessarily be avoided. Instead, the bleeding should be anticipated, and the surgeon should prepare the operative field as well as the surgical team to control the bleeding as rapidly and effectively as possible.
In the case of presacral hemorrhage, ligation of the internal iliac arteries or veins does not lessen the hemorrhage for the anatomic reasons cited above. In fact, even control of the infrarenal aorta and inferior vena cava will likely not decrease pooling of blood in the presacral veins because the vertebral venous system would remain intact.
Massive presacral bleeding needs to be promptly recognized, and is characterized by the following:
- Bleeding that suddenly occurs during mobilization of the distal rectum
- Gushing of blood from the pelvic floor that renders site localization difficult
- Bleeding persists despite significant hypotension or internal iliac artery control
Whenever massive presacral bleeding is encountered during an open procedure, the initial step is direct finger pressure control of the bleeding site as well as notification of the anesthesiologist and surgical team to prepare for the possibility of profound bleeding. If the bleeding site cannot be controlled in this manner, the posterior pelvis is packed with gauze to halt the hemorrhage. A second suction device is secured on the field and adequate illumination with overhead lighting or lighted retractors is ensured. Exposure can be further enhanced by extending the incision to the level of the pubis and removal of the specimen whenever possible.
Once the patient has been stabilized, blood products have been made available, and all personnel are adequately readied, the surgeon’s finger or pelvic packing is removed. It is imperative that the bleeding site is localized and the type of bleeding (i.e., presacral venous plexus, sacral basivertebral veins) is determined. The bleeding source is controlled by applying direct pressure using a small cylinder of gauze in the end of a fine clamp (ie - a "bridge" clamp with a "peanut"). Bleeding from veins of the presacral venous plexus can be suture ligated one-by-one using small (3-0) monofilament sutures that incorporate the presacral fascia, presacral vein, and deep connective tissue. Hemorrhage originating from a sacral basivertebral vein retracted into a sacral foramen requires obliteration using a variety of reported techniques used individually or in combination, and these include the following:
- Biologic tissue (e.g., epiploic appendix, omental scrap, rectus muscle) welding
- Directed coagulation (e.g., argon beam coagulator, electrocautery)
- Focal tamponade (e.g., bone wax, hemostatic sponge, matrix hemostatic agent, rectus muscle fascia)
- Hemostatic agents developed for military wounds
- Occlusive pin (e.g., thumb tack) placement
Internal Iliac Hemorrhage
Intentional or inadvertent dissection into the pelvic sidewall can result in hemorrhage from branches of the internal iliac vein or artery. For a standard TME procedure this type of pelvic sidewall bleeding is unusual, but for extended resections of tumors invading outside of the TME plane, this is an expected management challenge. Bleeding from this type of injury will lessen with internal iliac vascular control, and these are often managed with direct suture ligation using fine (5-0) monofilament suture ligatures and fabric pledgets, although clips and energy devices can sometimes be used.
It is important to arrest all bleeding prior to constructing any anastomosis because efforts to control presacral bleeding after the neo-rectum is in place can be more difficult and pelvic packing potentially threatens future problems affecting the neo-rectum or low-lying anastomosis.
If the bleeding cannot be controlled after the above-outlined approach or the patient becomes unstable or coagulopathic, the pelvis is packed to achieve hemostasis, and the abdomen is closed with plans to return to the operating room in 2-3 days after the patient has been optimized. One technique is by packing the pelvis with multiple Betadine-soaked kerlix wraps. Use of saline bags, balloon tamponade and tissue expanders have also been described.,, At re-look in 2-3 days , if persistent bleeding is noted, the approach can be repeated; however, this is rare.
Bleeding that occurs during a minimally-invasive proctectomy can be approached by following the same basic tenets. Occasionally, the bleeding can be controlled with local compression using a small piece of gauze or absorbable knitted fabric hemostat. If this fails, directed coagulation with the argon beam coagulator, biologic tissue welding, and/or focal tamponade with a variety of products and helical tacks can be utilized. The surgeon should have a low threshold to convert to open surgery if the bleeding cannot be quickly controlled.
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