Chapter 16 Operative Exposure in Abdominal Trauma: Exposure of Liver Injuries

This chapter will discuss the anatomical techniques utilized to address injuries to the liver.

Learning Objectives

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

1. Describe the key anatomical features required to expose and manage trauma to the liver.
2. Describe the common patterns of liver injury resulting in life-threatening hemorrhage.
3. Describe techniques to control hemorrhage of the liver.
4. Describe a stepwise approach to management of major liver injury.
5. Demonstrate the Pringle maneuver.
6. Describe the finger-fracture technique.
7. Demonstrate the use of staplers in liver surgery.
8. Demonstrate the steps in surgical mobilization and exposure of the liver.
9. Demonstrate exposure of the hepatic veins.
10. Demonstrate exposure of the retrohepatic inferior vena cava (IVC).
11. Describe options for vascular isolation of the liver.

Considerations

1. Hepatic injuries are common following both blunt and penetrating trauma.
2. Most liver injuries do not require operative intervention.
3. Morbidity and mortality from severe hepatic trauma is primarily related to hemorrhage from the juxtahepatic veins or, less frequently, the hepatic arteries.
   • The mortality for juxtahepatic venous injuries is reported to be between 50 and 80 percent.
   • Most deaths are caused by rapid intraoperative exsanguination, either due to failure to control initial hemorrhage or because of severe hemorrhage resulting from attempts to expose and directly control the injuries.
4. Venous injuries make up the bulk of life- threatening hepatic hemorrhage. Understanding the most common patterns of these venous injuries and the underlying anatomy will help dictate the proper management.
   • The major pattern of life-threatening liver hemorrhage (Type A) is intraparenchymal disruption of the major hepatic or portal veins, associated with disruption of the liver parenchyma and capsule, with bleeding coming directly through the disrupted liver substance (Figure 1).
   • A less common pattern of liver injury (Type B) occurs with avulsion of the juxtahepatic vein(s), associated with disruption of the suspensory ligaments of the liver and resultant uncontained hemorrhage issuing from around (rather than through) the liver (Figure 2).
5. Be certain to prep the patient from chin to knees in the event it is necessary to enter the chest or to gain access to the groin veins if a vascular conduit is needed.
6. The initial approach to controlling hemorrhage from liver trauma is a midline incision, with a subcostal extension if necessary to gain better exposure. On rare occasions, a sternotomy or extension into the right chest may be required.
7. The ultimate surgical goals of operative management of major liver injury are the following:
   • Control of hemorrhage
   • Control of bile leak
   • Debridement of devitalized liver
   • Drainage

• Attempts to evaluate the liver injury before adequate resuscitation may result in further blood loss and worsening hypotension.
• The first maneuver should be bimanual compression of the liver with one’s hands (attempting to recreate the liver’s normal three- dimensional shape) to slow bleeding, allow for temporary control of bleeding, and facilitate ongoing resuscitation.
• Perihepatic packing should be performed to return the liver to its normal three-dimensional shape. Do not pack within the liver parenchyma itself; this will divide the liver parenchyma further and may worsen bleeding.
• Be a minimalist. If packing stops the bleeding in an unstable patient, truncate the operation (damage control).
• If packing does not stop the bleeding, move to a Pringle maneuver (described later in this chapter).
• In a hemodynamically unstable patient who requires damage control for major liver injury, the primary operative goal is control of hemorrhage.
• If initial packing and the Pringle maneuver fail to control hemorrhage, mobilization of the liver, rapid exposure of the injury, and vascular control are paramount to a successful outcome.
• Angioembolization has a role in both pre- and postoperative management of hepatic trauma with hemorrhage.
• Aortic clamping is not necessary to control liver hemorrhage and may compound ischemic insult in a patient who is already decompensated.

Anatomical Considerations

• Understanding the relevant anatomy is vital to management of significant injuries to the liver.
• The retrohepatic vena cava is closely adherent to the back of the liver, lying entirely within the “bare area” of the liver (i.e., the portion lacking a capsule and completely circumscribed and contained by the hepatic suspensory ligaments).
• There is direct contact between the posterior aspect (caudate lobe) of the liver and the vena cava, and the liver parenchyma partially (approximately 90 percent) or completely (approximately 7 percent) encircles the retrohepatic vena cava, making exposure and repair challenging.
• The portal vein, which is formed by the merging of the superior mesenteric and splenic veins, supplies approximately 75 percent of the blood flow to the liver.
• The portal vein enters the liver through the porta hepatis, along with the hepatic artery and common hepatic duct, and divides into right and left branches that terminate in sinusoids. The blood from the sinusoids is collected by hepatic veins that empty into the vena cava (Figure 3).

• Venous drainage of the liver parenchyma occurs in an anterior-to-posterior and inferior- to-superior direction through the intrahepatic veins, which ultimately coalesce into three hepatic veins (right, middle, and left) that drain into the IVC superiorly (Figure 3).
• As described by Couinaud, the liver is divided into eight functionally independent segments. The center of each segment contains a branch of the portal vein, hepatic artery, and bile duct. Each segment has vascular outflow through the hepatic veins (Figure 3).
• The portal vein anatomically divides the liver into upper and lower segments (Figure 3).
• The middle hepatic vein divides the liver into right and left lobes, or hemi-livers (Figures 3 and 4). An external reference line—between the middle of the gallbladder fossa anteriorly to the IVC posteriorly (Cantlie’s line)—is used to separate the right and left lobes, with the middle hepatic vein found at the base (Figures 4 and 17).

• The right hepatic vein divides the right lobe into anterior (segments 5 and 8) and posterior (6 and 7) segments (Figures 3 and 4).
• The falciform ligament divides the left lobe into a medial (segment 4) and lateral (2 and 3) segments. The left hepatic vein is also located in this divide (Figure 4).
• The hepatic veins are largely intraparenchymal, with the extraparenchymal portion being between 1 cm and 2 cm in length. In approximately 85 percent of cases, the left and middle hepatic veins fuse before emerging from the liver to form a single extraparenchymal trunk that enters the vena cava (Figures 3 and 4).
• The IVC joins the right atrium approximately 3 cm above the superior end of the retrohepatic section and can be exposed in the pericardial sac (Figure 5).

• In addition to the main hepatic veins, there are several (an average of seven) short accessory hepatic veins directly between the liver and the IVC (Figures 5 and 6). These veins may be up to 1.5 cm in diameter and are short, thin, fragile, and prone to injury. As such, they can be a source of significant bleeding, either from the traumatic injury or from iatrogenic injury while mobilizing the liver.

• The suspensory ligaments of the liver include the falciform, coronary, and triangular ligaments (Figure 7). These ligaments tether the liver to the diaphragm and retroperitoneum and support the weight of the liver, preventing traction on the extraparenchymal hepatic veins. Additionally the ligaments contain the bare space of the liver, into which bleeding from the retrohepatic vena cava and extraparenchymal hepatic veins will flow.
• It is important to not mobilize the liver unless absolutely indicated, as this risks opening a contained hematoma with resultant massive hemorrhage.

Techniques

• Hemorrhage from the liver may be controlled with a variety of techniques, ranging from simple to complex:
  • Bimanual compression (restoring three- dimensional shape of liver)
  • Packing
  • Simple suture
  • Omental packing
  • Balloon tamponade
  • Pringle maneuver
  • Tractotomy with vascular and ductal ligation
  • Finger fracture
  • Division of liver parenchyma with a stapler
  • Hemostatic agents
  • Argon beam or electrocautery coagulation
  • Radiofrequency energy (Aquamantys)
  • Nonanatomic liver resection
  • Hepatic mobilization
  • Hepatic vascular isolation/bypass
  • Anatomic liver resection (rarely needed acutely; more common at a return to the operating room after damage control)

General Approach to Major Liver Injury

The approach to bleeding in major liver injury must follow an organized, systematic approach (Figure 8).

Bimanual Compression and Packing

• Bimanual liver compression: The first maneuver when entering the abdomen for managing a major liver injury (while not knowing the precise location) is temporary control of the bleeding from the liver with bimanual compression. This will allow anesthesia some time to catch up on volume resuscitation in a hypotensive patient. Two concepts are critical in this maneuver:
  • First, compress the liver back to its normal three-dimensional shape using both hands. The right hand should grasp the left lateral segment, and the left hand should grasp the lateral right lobe. Then move the two hands toward each other, compressing the right and left hemi-livers back to restore normal anatomy (Figure 9).
  • Second, immediately after accomplishing the above, push the entire liver posteriorly and slightly cephalad. This maneuver will usually slow bleeding from the hepatic veins or retrohepatic IVC.

• • If the bleeding seems to be controlled with bimanual compression, this is a good indication that packing alone will be successful.
• Perihepatic Packing: Proper packing of the liver is a skill that all surgeons dealing with hepatic injury should master. The key to packing the liver is to recreate its three-dimensional anatomy using packs above, below, and to the sides. The packs are placed between the liver and the diaphragm, abdominal sidewall, and infrahepatic structures (Figure 10). Packing is about the quality, not the quantity.
• If bleeding stops after packing, it is best to leave the packs in place without further manipulation. Avoid the temptation to remove the packs once placed.
• Packs may be left in place while performing a damage control laparotomy or if the patient is to undergo angiographic evaluation and embolization of the liver to control hemorrhage or embolize pseudoaneurysms.
• It should be noted that packing too tightly may compress the IVC, impeding venous return.
• At subsequent operation, the packs can be carefully removed, allowing for localization and control of any residual bleeding.

Simple Suture of Liver Lacerations

• Most minor and many moderate liver lacerations can be treated with simple suturing. Some authors recommend using a large, blunt needle and taking large bites of the hepatic capsule and parenchyma using a mattress technique.
• While oversewing the bleeding liver with a large needle may at times be lifesaving, this technique may also leave untreated a major injury deeper within the liver parenchyma. This will ultimately cause a problem, and as such oversewing should rarely be considered in the case of major liver lacerations.

Hemostasis Using Topical Hemostatic Agents and Omental Pack

• Hemostasis can be accomplished in less severely injured livers using a variety of techniques.
• Topical hemostatic agents may be placed or sprayed on the exposed, raw hepatic parenchyma to assist with maintenance of hemostasis.
• Once surgical hemostasis has been achieved, a “tongue” of vascularized omentum may be mobilized and placed in the parenchymal wound, as shown in Figure 11.
• Large liver sutures (0-chromic sutures on blunt liver needles) may be placed to keep the omentum in place and to close dead space.

Balloon Tamponade of Through-and- Through Liver Injury

• Through-and-through penetrating injuries to the substance of the liver can occasionally be controlled with balloon tamponade, using a commercial device such as the esophageal portion of a Sengstaken–Blakemore tube, a Foley catheter with a 30 cc balloon, or a homemade device in which a red rubber catheter is placed inside a Penrose drain and inflated with saline (Figure 12).
• The balloon is essentially “packing” the liver from the inside of the injury tract, and subsequent removal of the device after the patient has been resuscitated can be accomplished similar to removal of perihepatic packs.
• If the balloon is deflated and bleeding continues, reinflate the balloon and send the patient for angioembolization.

Pringle Maneuver to Control Hemorrhage

Considerations

• The Pringle maneuver should be considered as an early step in vascular control of an injured and massively bleeding liver (after bimanual compression and packing).
• Digital occlusion or clamping of the portal vein and hepatic artery during the Pringle maneuver interrupts the blood flow in these vessels.
• The Pringle maneuver is both diagnostic and therapeutic. If the bleeding slows, the injury is either to the hepatic artery or portal vein branches. Bleeding from these vascular structures should then be approached directly within the liver and oversewn. If the bleeding persists, you have confirmed the hepatic veins or retrohepatic IVC (or more rarely, aberrant arterial anatomy, as described below) as the source of ongoing blood loss.

Technique

• The index finger is inserted into the inferior aspect of the foramen of Winslow, and when the thumb is pinched on top of the index finger, the structures of the portal triad are effectively controlled (Figure 13). A vascular clamp or vessel loop may be used to replace the fingers if longer-term control is needed.
• The safe duration of portal triad occlusion using the Pringle maneuver in a hypotensive trauma patient is not known. If possible, the clamp should be intermittently released to limit total warm ischemia time.
• The Pringle maneuver will be ineffective in patients with a replaced left hepatic artery, which typically arises from the left gastric artery.

Direct Surgical Control of Parenchymal Injuries

Technique

• At times, injuries in the liver must be enlarged to adequately expose and oversew bleeding vessels. With these deeper penetrating or blunt injuries, the finger-fracture technique (Figure 14) may be used to identify deep bleeding vessels, which can then be controlled with surgical clips or ties (Figure 15).

• The finger-fracture technique is a method of intrahepatic digital dissection in which the capsule of the liver is incised and a thumb and forefinger are used to gently “tear” through the liver tissue by gently squeezing and rubbing the fingers together; this exposes the intrahepatic vessels and ducts (Figure 15) so that they can be clamped and then ligated or clipped.
• Exposure of the parenchymal injury allows suturing of exposed vascular and ductal structures, as well as direct application of surgical clips, staplers, and/or tissue coagulation with Bovie cautery, argon beam coagulation, or an Aquamantys device.
• Alternatively, a stapler with a vascular load may be used to divide the liver parenchyma (Figure 16).

• A blunt-ended clamp may be passed into the liver along the intended transection plane and used as a guide before placing the blades of the stapler.
• A stapler may be used to rapidly expose injury to the central liver, with exposure of the middle hepatic vein accomplished by firing the stapler along Cantlie’s line (Figure 17).
• The stapler may also be used to perform a nonanatomic resection.
• If there is still significant bleeding after the aforementioned maneuvers, there is likely an injury to one of the other hepatic veins or the retrohepatic vena cava, and the liver will need to be fully mobilized with control of the IVC above and below the liver.

Surgical Mobilization and Exposure of the Liver

Considerations

• The decision to mobilize the liver should be made only after careful consideration of the consequences. Injuries to the retrohepatic vena cava and the hepatic veins may be contained by the liver and its attachments. Mobilization of the liver in these circumstances may convert a controlled situation into one of uncontrolled hemorrhage, with potentially dire consequences.

Technique

• Self-retaining retractors are essential for management of major liver injury. The goal is to lift the subcostal margins both cephalad and anteriorly (away from the table).
• For severe right lobe injury or retrohepatic injury, a right subcostal extension off the midline incision may facilitate exposure and access.
• Mobilization of the liver requires bringing it to the midline. This requires division of the hepatic ligaments.
• The liver is retracted caudally and medially to divide and ligate the falciform ligament (Figure 18).
• Further mobilization of the liver requires division of the right coronary and triangular ligaments (Figures 19 and 20) to expose the bare area of the liver and allow rotation of the right lobe of the liver toward the midline (Figures 20 and 21). Avoid damaging the diaphragm as you perform this mobilization.
• The left lobe of the liver can be mobilized by taking down the left triangular, falciform, and the left coronary ligaments.
• Division of the hepatoduodenal and gastrohepatic ligaments will give access to the lesser sac, the portal vein, the medial aspect of the IVC, and the caudate lobe of the liver, if required (Figure 22).

Possible Pitfalls of Liver Mobilization

• Mobilization of the liver must be performed with care, as the retrohepatic vascular structures are more anterior than one might expect and can be easily injured by traction or errant dissection.
• Success in controlling suspected retrohepatic caval bleeding with initial packing should preclude liver mobilization in the acute setting. If the liver is mobilized in this setting, uncontrolled bleeding may be unleashed, requiring the much more drastic (and often lethal) maneuvers described in this chapter.
• Major liver injuries are usually accompanied by significant bleeding, making repairs technically challenging.
• Complete knowledge of hepatic anatomy and maneuvers to rapidly obtain exposure—and the confidence to do so—are essential for salvage of patients with juxtahepatic venous injury.
• Hemorrhage control of complex injuries may require hepatic isolation with proximal control of the suprahepatic IVC, distal control of the infrahepatic IVC, and the Pringle maneuver.
• The most commonly used technique for hepatic vascular isolation is the Heaney maneuver (described below).
• On rare occasions and if available, venovenous bypass may be needed if the patient does not tolerate hepatic vascular isolation. In select centers, this has been used as an adjunct to primary injury repair or as a bridge to potential liver transplant.
• Other described hepatic vascular isolation techniques, such as the atrial caval (Schrock) shunt, have had few reported survivors and are mostly of historic interest only.

The Heaney Maneuver

• This maneuver of hepatic vascular isolation involves clamping the suprahepatic and infrahepatic IVC in addition to application of the Pringle maneuver. This technique results in severe acute decrease in venous return to the heart, with sudden cardiac arrest as a possible outcome. Attention to aggressive volume infusion, including the use of large-bore infusion catheters into the large veins of the neck, should be considered to preserve venous return and maintain cardiac output.
• The original Heaney maneuver described opening the pericardium from the abdomen, as one would do for a pericardial window, and controlling the suprahepatic IVC within the pericardial sac (Figure 23).
• In the majority of cases, the suprahepatic IVC can usually be clamped in the abdomen, between the diaphragm and the top of the liver, by mobilizing and retracting the liver caudally and anteriorly.
• Suprahepatic intra-abdominal control of the IVC requires mobilization of the suspensory ligaments of the liver and entry into the gastrohepatic ligament, as previously described, in order to expose the segment of IVC above the top of the liver and below the diaphragm for control (Figure 24).
• Aggressive dissection of the suprahepatic IVC should be avoided, with just enough dissection to enable placement of an occluding clamp (Figure 25).
• Control of the infrahepatic IVC may be challenging, particularly if active hemorrhage is ongoing.
• The segment of the IVC below the liver edge and cephalad to the renal veins can be quite short, and the renal veins may be injured if one fails to recognize this anatomy (Figure 26).
• The hepatoduodenal window is opened and the lower portion of the liver is retracted up off the IVC in a cephalad direction to allow for visualization of and clamping of the infrahepatic IVC between the lower surface of the liver and the renal veins. With the clamp angled in a cephalad direction to avoid injury to the renal veins the vein is carefully closed (Figure 27).

Alternative Technique: Hepatic Venovenous Bypass

• Venovenous bypass involves returning blood from the lower body to the heart.
• This technique is unlikely to be used outside of specialized centers, as it requires the time, pump, and technician to set up the bypass following vascular isolation.
• On occasion, if the patient is hemodynamically stable enough and a very complex liver or retrohepatic injury is documented by computed tomography, placement of shunts for venovenous bypass and readiness of the team prior to entering the abdomen may be advisable.