Operative procedure Sai
The best procedure to follow in any unplanned vascular injury is first to control the bleeding with direct pressure; this may be accomplished with a finger or by packing with a sponge. Once the bleeding is controlled, get help (in terms of both additional staff and specialist advice, when needed) and formulate a plan before anything further is done.
Arterial control and repair
When dealing with an arterial injury or planned resection and repair, proximal and distal control are vitally important—this point cannot be overemphasized. In general, circumferential dissection of the aorta and common iliacs is counterproductive because of the risk of venous injury; dissection limited to the sides is usually sufficient. If the aorta is to be clamped, dissection should be carried down to the spine. In all arterial surgery, a dissection plane directly on the arterial adventitia is easiest and safest (Figure 6). Systemic heparin (125 units/kg) should be administered before clamping if bleeding is not diffuse; anticoagulation is reversed after blood flow is re-established with protamine sulfate (1 mg per 100 units of heparin administered).
The ureter passes over the iliac bifurcation (Figure 7), making continuous exposure of the top of the iliac vessels problematic.
Small lacerations of the major vessels, especially if oriented transversely to the vessel axis, can be repaired using monofilament, nonabsorbable suture (3-0 or 4-0 for the aorta, 5-0 for the iliac arteries). When the artery is diseased, the needle should be passed from inside to outside to avoid dislodging intraluminal plaque. All knots should be extraluminal (Figure 8). Direct repair of longitudinal injuries in the iliac (or smaller) vessels will usually narrow the lumen, so patch repair is preferred (Figures 9 and 10).
Any defect involving actual tissue loss, especially encompassing the entire circumference of a vessel, will usually require an interposition graft and is beyond the scope of this discussion.
Venous control and repair
Major venous injuries, somewhat paradoxically, can be more life-threatening than arterial defects. Veins are thin-walled, do not hold their shape, and are often less accessible. When faced with a major venous injury (dark, nonpulsatile bleeding), the first step is to apply gentle pressure. The temptation to control the injury with forceps or a clamp, even if the tear is apparently visible, should be resisted; doing so will often extend the tear and often convert a remediable situation into one that is very serious indeed. Several options are available. First, pressure itself will often solve the problem; if you are fortunate, resist the temptation to fiddle any further! Don't look, don't dissect, just accept your good fortune and move on. Second, pressure
Figure 6
Exposure of the infrarenal aorta (duodenum is retracted laterally and superiorly). Note that the aorta itself is well cleared proximally and distally, without any dissection (e.g. digitally or with sponge-sticks), can control the bleeding enough to make the defect visible. Third, blind suturing is sometimes acceptable if no critical structures (such as the ureter) are near. Finally, ligation is usually safe and well tolerated, especially if the patient's life is at risk.
In these situations, obtaining help, in terms of both experienced assistants to provide exposure and vascular surgical assistance, is of utmost importance, as is gaining control of the hemorrhage without doing further damage so that a plan can be formulated and carried out.
Vascular patches
Most longitudinal defects, even if no tissue is resected, will result in a narrowed lumen if repaired primarily. Thus, patch angioplasty is required for repair of most longitudinal defects in the iliac or smaller vessels.
Autologous tissue is preferred, especially in the presence of a potentially infected field. The greater saphenous vein is an excellent choice, as is the hypogastric artery It is important that the endothelial surface should be oriented luminally If, in a clean field, autologous tissue is not available, Dacron or polytetrafluoroethylene (PTFE) can be used. Fine monofilament nonabsorbable suture material is used. A continuous suture is perfectly adequate. Exposure is best achieved by starting at one end and placing the first two or three stitches in a 'parachute' fashion before bringing the patch in contact with the vessel (see Figure 9). The first ('heel') suture should be mattressed so that the needle always passes from inside to
Figure 7
Ureter and the iliac bifurcation
Figure 8
Suture technique for closure of a transverse arteriotomy outside the artery. The suture is then continued around the patch and the knot tied along a long end of the patch (see Figure 10).
Figure 9
Initial stages of longitudinal arteriotomy: patch closure
Figure 10
Completed closure
Caval interruption
Malignancy has long been known to be associated with hypercoagulability. When combined with pelvic surgery, immobilization and often advanced age, the risk of deep venous thrombosis and pulmonary embolus is frequently high enough to warrant prophylactic caval interruption. Caval interruption can be performed by placement of one of variety of intraluminal devices percutaneously via the groin or subclavian vein into the infrarenal cava. During laparotomy, however, the cava can be effectively interrupted by means of an external clip.
Figure 11
Location for the clip
1 Inferior vena cava
2 Colon and duodenum being mobilized to right
Figure 12
A clamp is used to grasp the string attached to the DeWeese-Adams clip
The clip is applied to the inferior vena cava (IVC) below the level of the renal veins (Figure 11). The cava is exposed by mobilizing the right colon and the duodenum in the avascular plane (Kocher maneuver). Circumferential exposure along a short length of the IVC is required.
A large right-angled clamp is gently passed behind the cava and used to grasp the string attached to the bottom jaw of the clip (Figures 12-l4). The bottom jaw is then gently brought behind the cava, and the string tied over the notch on the top, bringing the jaws together over the cava. This creates multiple small channels, each incapable of allowing a significant embolus to pass. Even though pulmonary embolus is
Figure 13
The clip is brought around the inferior vena cava
Figure 14
The clip in position prevented with a high degree of certainty, if a deep venous thrombosis of the leg is present, anticoagulation is best continued (if not contraindicated) in an attempt to reduce the risk of extension of clot and post-phlebitic sequelae.
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