Living Liver Donor

Living donor liver transplantation (LDLT) began more than 10 years ago and quickly became a widely accepted technique in children.^{[41] [52]} The regenerative capability of the liver has long been recognized and exploited, and complete recovery of liver function in both the donor and recipient can be expected after donation of a portion of the liver. The primary presurgical consideration is determination of the mass of transplanted liver that is needed to support a given patient and to leave enough liver mass with the donor. Several formulas, including the graft-recipient body weight ratio and graft weight as percentage of standard liver mass, are used to ensure adequate liver mass in the donor and recipient.^{[37] [53]}

Pediatric LDLTs generally require resection of only the left lateral segment (segments II and III) or a total left hepatic lobectomy (segments II, III, and IV) to provide sufficient liver mass. These type of grafts are expected to grow along with the patients as they mature. From a surgical point of view, a left hepatectomy is less complex and the duration of surgery is therefore shorter.^{[54] [55]}

This technique has been extended to adult patients as well. The number of LDLTs performed annually in the United States grew slowly through most of the 1990s (representing about 1% of liver transplants) but increased dramatically beginning in 1998 (from 56 in 1996 to 515 in 2001). This large increase is primarily due to increased numbers of right hepatic lobectomy for adult-to-adult LDLT. The surgical technique for right hepatectomy involves separation of the right hepatic lobes (segments V, VI, VII, and VIII) from the left ( Fig. 56-1A and B ). This technique results in a graft in the range of 500 to 1000 g, which leaves the donor with about a third of the original liver mass. Volumetric studies have shown that the donor's liver regains its original size in a surprisingly short time, often within weeks to months.^{[56] [57]} However, functional recovery may take much longer.^{[58] [59]}

Most LDLTs have been performed in patients with chronic liver failure, and accordingly, they are usually done on an elective basis. In rare cases, albeit controversial, living donor transplantation may be performed in patients with very advanced disease or decompensated end-stage liver disease.^{[60] [61]} The ethical issues, for example, coercion of the donor, involved in these cases are even more pronounced.^{[62] [63]} In addition, relative inexperience with the procedure may lead to an unacceptably high complication rate. Worldwide, at least 8 liver donor deaths have occurred; in the United States, where approximately 1000 LDLTs have been performed, 3 donor deaths have occurred.^[64] The overall complication rate is variable^[39] and

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Figure 56-1 A, Segmental liver anatomy. Each segment is supplied by a portal pedicle consisting of the hepatic artery, portal vein branch, and bile duct. B, Segments V to VII are frequently used for adult-to-adult living donor transplantation. (Redrawn from Renz JF, Yersiz H, Farmer DG, et al: Changing faces of liver transplantation: Partial-liver grafts for adults. Hepatobil Pancreat Surg 10:31–44, 2003.)

The intraoperative care of patients undergoing right hepatectomy for liver donation is similar to that of other patients having hepatic surgery. Preoperative placement of a thoracic epidural catheter is performed in some transplant centers; however, others use only patient-controlled analgesia for postoperative pain control. The choice of postoperative pain control appears to depend in part on the postoperative monitoring capabilities and the familiarity of the nursing staff on the floor with each technique. Avoidance of epidural catheter placement based on concerns of postoperative coagulopathy from extensive hepatectomy seems to not be justified. The prothrombin time usually peaks on postoperative day 2 to 3 and returns to baseline on day 5. Several studies have failed to demonstrate any adverse effect of epidural catheters in this patient population.^{[59] [68] [69]} The largest study was reported from Japan and involved 755 donors who received an epidural catheter for postoperative pain management.^[70] No complications associated with the epidural catheter were reported. However, because of the very low incidence of epidural hematomas overall, these studies lack the power to assess the risk of epidural hematoma developing in this patient population. General anesthesia is standard and may consist of a balanced technique or be combined with intraoperative supplementation of epidural analgesia.

Intraoperatively, the patient is placed in a supine position, frequently with one arm tucked (right or left) at the side and the other abducted. An orogastric/nasogastric tube is placed for decompression of the stomach and improved surgical exposure, particularly when a left hepatectomy is performed. Two large-bore intravenous catheters and invasive arterial blood pressure monitoring are used in most centers.^{[59] [70]} Continuous monitoring of CVP has been advocated by some to ensure a low CVP because an elevated CVP is considered to be one of the prime determinants of bleeding from liver parenchyma during transection.^[71] Hence, fluid is administered judiciously until the donor liver lobes are removed. An autotransfusion system is used at most centers, and in addition, patients frequently donate 1 to 2 U of whole blood preoperatively. At centers where this procedure is performed on a routine basis, blood loss is generally well below 1 L.^{[59] [72]} However, because of the nature of the procedure, preparation and vigilance for sudden extensive blood loss are always warranted.

Frequently, an L-shaped (hockey stick) or standard bilateral subcostal incision with a midline extension is used. The procedure can be divided into three stages: mobilization of the liver and identification of vascular structures, transection of the liver, and hemostasis and closure. During the first stage of the operation, manipulation of the liver can occasionally result in decreased venous return to the heart with consequent brief episodes of hypotension. It is important to be aware of this possibility before initiating any therapy. The parenchymal division is completed with several different devices such as the CUSA ultrasonic surgical aspirator (Valley Lab, Boulder, CO) or the Harmonic Scalpel (Ethicon Endo-Surgery, Somerville, NJ). ^{[58] [59]} After the vasculature of the donor lobe is clamped and divided, the lobe is removed and the vasculature and bile duct are oversewn. Subsequently, hemostasis is achieved and the abdomen closed.

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In uncomplicated cases, the patient can be extubated in the operating room and transferred to the postoperative care unit. Admission to the intensive care unit (ICU) is not generally necessary. Nevertheless, standard practice in some institutions has been to manage living liver donors in the ICU in the early postoperative period.