Chapter 20 Operative Exposure in Abdominal Trauma: Exposure of Kidney, Ureter, and Bladder Injuries

This chapter will discuss surgical exposure of both kidneys, with a focus on how the different anatomic relationships and vasculature impact surgical exposure in emergent situations. In addition, surgical exposure of ureters and the urinary bladder will also be discussed.

Learning Objectives

By the end of the ASSET course, participants should be able to do the following:

1. Demonstrate the steps to obtain surgical exposure of the kidneys.
2. Demonstrate vascular isolation of the kidneys.
3. Demonstrate exposure of the ureter.
4. Demonstrate bladder exposure by opening the anterior wall/dome of the bladder.

Kidney—Considerations and Investigations

• The kidney is the most commonly injured genitourinary organ.
• Indications for operative intervention include hemodynamic instability, expanding or pulsatile hematoma discovered during trauma laparotomy, active bleeding into the peritoneal cavity, or an injury to the extrarenal urinary collecting system.
• In a stable patient, injury is usually diagnosed by CT scan with IV contrast (Figure 1).
• The presence of a vascular blush on CT scan (Figure 2) indicates active bleeding. This can be managed by angiographic embolization in a hemodynamically stable patient, or as part of a trauma laparotomy in an unstable patient.
• While historically emphasized, the use of a single-shot intravenous pyelogram (IVP) has fallen out of favor and should be discouraged.
• The presence of a unilateral nonperfused kidney may indicate a blunt vascular injury with occlusion of the renal artery. Whether an urgent renal exploration or angiographic intervention is warranted depends on whether the other kidney is perfused, the time elapsed since injury (warm ischemia time), the prioritization of other injuries, and the ability of the patient to tolerate a revascularization procedure.
• When discovered at laparotomy, penetrating wounds that extend into the retroperitoneum may require exploration for possible injury to the kidney, ureter, and vascular structures, unless preoperative CT injury assessment indicates that observation is appropriate.

Operative Exposure

• Renal injuries are explored through a generous midline incision.
• Though the kidneys are bilateral organs, each has quite different anatomic considerations, which must be kept in mind while exposing the vasculature.
• Before proceeding with nephrectomy, it is important to confirm the presence of a normalsized contralateral kidney by palpation.

Right Kidney

• Exposure of the right kidney requires mobilization as follows:
  • Right-to-left medial visceral rotation (Figure 3), as described in chapter 15
  • Kocher maneuver (chapter 15) to mobilize the duodenum off the right kidney

Left Kidney

• Exposure of the left kidney begins with left-toright medial visceral rotation (modified Mattox maneuver) of the descending colon, splenic flexure, spleen, and distal pancreas (Figure 4), as described in chapter 15.

Vascular Control

• Proximal control of the renal vasculature should be obtained before entering Gerota's fascia in the presence of a significant renal hematoma. There are two main ways to obtain renal vascular control: midline and lateral-to-medial.

Midline Approach

• Vascular control can be obtained by entering the retroperitoneum at the base of the mesocolon, medial to the inferior mesenteric vein, as shown in Figure 5. It is important to open the retroperitoneum from the ligament of Treitz to the aortic bifurcation.
• This exposure allows control of the renal arteries at their origin from the aorta prior to entering significant perinephric hematomas.
• Once the retroperitoneum is opened, the renal vessels can be isolated and controlled near the midline, as depicted in Figures 5 and 6.
• Left renal vascular control:Vessel loops are placed around the left renal vein first, as it is typically anterior, and then around the left renal artery.

• Right renal vascular control: The right renal artery is isolated at its origin by slightly retracting the medial portion of the left renal vein cephalad, as shown in Figure 6. After a vessel loop is placed around the right renal artery, the right renal vein is isolated at its junction with the inferior vena cava (IVC).
• It is important to remember that the adrenal vein usually drains directly into the IVC on the right and into the renal vein on the left.
• The left renal vein may be ligated if necessary, as there is sufficient collateral venous flow through gonadal and adrenal veins.

Lateral-to-Medial Approach

• Either kidney can be rapidly accessed from lateral to medial if the patient is in extremis. This is easier and quicker, with less blood loss in patients with large central hematomas.
• After mobilization of the colon, the retroperitoneum and Gerota's fascia are entered, and the surgeon’s hand is placed around the kidney from lateral to posterior.
• With the hand in that position, the vascular pedicle can be easily controlled with the thumb and forefinger. The kidney can then be rotated medially and brought up into the surgical field.
• The vascular pedicle can be controlled with a vascular clamp (or a crushing clamp, if nephrectomy is to be performed) while the ureter is isolated.

Ureter—Considerations and Investigations

• Most ureteral injuries are penetrating and are often associated with vascular injury. These are most often diagnosed at laparotomy. Preoperative contrast imaging may not be feasible or appropriate in unstable patients prior to laparotomy.
• Blunt injury to the ureter is rare, but when it occurs is often associated with disruption of the ureteropelvic junction. Blunt avulsion injuries of the ureter are more common in pediatric patients.
• The longitudinal blood supply to the ureter runs between the muscularis and the adventitia; dissection outside the adventitial layer avoids devascularization, which otherwise may result in stricture or leak.
• If the patient is being treated in a damage control fashion, ureteral repair should be delayed until the patient’s physiology will permit. In this setting, an appropriately sized tube (feeding tube or red rubber) can be placed into the proximal end of the ureter and exteriorized to provide urinary drainage. In cases of extremis, simple drainage of the ureteral bed may also be employed.
• Repair of complex ureteral injuries is beyond the scope of this manual and is best accomplished by surgeons experienced in such repairs, if and when the patient’s physiology permits.

Operative Exposure of Ureters

• Exposure of the ureters can be accomplished by right-to-left or left-to-right medial visceral rotation, or through the root of the mesentery (Figure 7), depending on the area of injury.
• The ureters lie directly over the psoas muscle and will cross the pelvic brim over the top of the iliac arteries (Figure 7).
• In order to differentiate the ureter from the gonadal vessels, it may be helpful to observe for peristalsis or lightly compress the ureter with vascular forceps to stimulate peristalsis (Kelly’s sign).
• Exposure near a hematoma may be difficult, and it is easier to identify the ureter in an area slightly removed from discernable trauma.
• If the ureter is in a hematoma, small injuries can be difficult to identify, and injecting methylene blue or indigo carmine intravenously (both are excreted in the urine) may be helpful in ensuring that no injuries are missed. Place a dry white sponge over the site of possible injury, and examine it 10 to 15 minutes after the dye is injected.

Operative Repair of Ureteral Injuries

• While exposure is the primary focus of this manual and course, repair of a transected ureter is certainly within the skill set of surgeons caring for the traumatically injured, if the patient’s physiology permits and subspecialty expertise is not readily available.
• The steps of ureteral repair are detailed in Figures 8 and 9 and are as follows:
  • Identify the injury, and mobilize the transected ends (Figure 9). Mobilization should be minimized to prevent devascularization.
  • The ends of the transected ureter are debrided and spatulated using Potts scissors, with the spatulation on opposite surfaces (i.e., anterior on one and posterior on the other).

• A double-J stent is placed into each end of the transected ureter. The distal end of the stent is placed into the bladder and the proximal end into the calyx of the kidney. This will allow for cystoscopic retrieval of the stent following healing.
• The ureteral ends are then sewn together over the stent using interrupted absorbable sutures, as permanent sutures are lithogenic.
• Complex ureteral injuries and injuries involving significant portions of damaged or missing ureter will require repairs best left to urology colleagues. As mentioned, in the damage control setting, the proximal ureter can be intubated with any small tube that can then be brought out through the skin.

Urinary Bladder—Considerations

• Bladder injuries can be diagnosed using conventional or CT cystography (Figure 10).
• Blunt extraperitoneal injuries usually accompany pelvic fractures and usually do not require operative exploration. Such injuries can usually be managed with transurethral catheter drainage alone.
• Penetrating bladder injuries typically will require surgical exploration and repair.
• Intraperitoneal injuries (blunt and penetrating) require surgical repair. Blunt injuries usually result from direct impact to the anterior lower abdominal wall in the setting of a full bladder, causing a large laceration of the dome of the bladder.

Operative Exposure of the Bladder

• The bladder should be explored during trauma laparotomy and will be decompressed if a Foley catheter has been inserted. The Foley can be clamped or filled retrograde to assist evaluation of the bladder.
• Bladder injury discovered at laparotomy mandates exploration of the inside of the bladder (Figure 11). This can generally be done through the injury or by extension of the injury.
• Exploration of the interior portion of the bladder requires inspecting the wall of the bladder, looking for other wounds, and inspecting the trigone of the bladder.
• The trigone is the smooth triangular region of the internal urinary bladder formed by the two ureteral orifices and the internal urethral orifice.
• The ureteral orifices should be visualized bilaterally and efflux of clear urine seen. If this is not observed (and the injury is in proximity), ureteral injury may be present, and insertion of a stent (Figure 11) or further exploration is warranted.
• Repairs to the bladder are made with two layers of absorbable suture.
• A suprapubic catheter is typically not required, but it is necessary to have a large-bore Foley catheter inserted until a cystogram demonstrates no leak postoperatively.
• A suprapubic catheter may be valuable or necessary when there is a concomitant posterior urethral injury that precludes safe placement of a urethral catheter, or when the bladder is severely injured and the repair is tenuous or incomplete.