Figure 21.1 Common liver resections – Brisbane classification.
a. Right anterior
b. Right posterior
c. Left medial
d. Left lateral (Figure 21.1)
• Segmentectomy
• Right trisectionectomy refers to right hemihepatectomy extended to include the left medial section (Figure 21.1)
• Left trisectionectomy refers to left hemihepatectomy extended to include the right anterior section.
The major ligaments of the liver are the falciform, left triangular, right triangular and inferior and superior leaves of the coronary ligament; however, it is the major vascular structures (hepatoduodenal ligament and hepatic vein–IVC confluence) that anchor the liver in position. The gastrohepatic (lesser) omentum extends from the lesser curves of the stomach to the ligamentum venosum, separating the left lateral section (anteriorly) from the caudate lobe (posteriorly). It contains the hepatic branches of the anterior vagal trunk (to the liver, gallbladder and bile ducts) and any accessory left hepatic artery from the left gastric (present in approximately 20% of people). The right free edge of the lesser omentum envelops the hepatoduodenal ligament with the hepatic artery proper (lying left anterior), common bile duct (right anterior) and portal vein (posterior). The accessory right hepatic artery branch of the superior mesenteric artery (present in approximately 12% of people) lies posterior to the common bile duct in the hepatoduodenal ligament. The epiploic foramen provides passage to the lesser sac and is bound posteriorly by the infrahepatic IVC. The bare area of the liver is bound by the right triangular ligament (laterally), and inferior and superior leaves of the coronary ligament, and harbours the right adrenal gland (laterally) and IVC (medially).
Anatomical variations in vasculobiliary supply [5–7] and venous drainage [8] of the liver are common such that ‘standard’ anatomy is present in only about half of us. These variants have received far greater attention since the advent of split liver and live donor liver transplantation, in which two functional livers are created from one. Not all variations are as vital in therapeutic liver resection; however, some are important, and these are mentioned specifically under the respective operative procedures (see the ‘Surgery’ section of this chapter).
21.4.1 Preoperative imaging
Good-quality cross-sectional imaging with computed tomography (CT) or magnetic resonance imaging (MRI) is the cornerstone of preoperative planning. The imaging should be recent, especially if neoadjuvant therapy has been given. CT has the advantage of superior spatial resolution, whereas MRI provides superior contrast resolution, and is often needed to accurately assess the relation of the lesions to vascular structures. Carefully targeted ultrasound (US) with the surgeon in attendance can also be very useful, especially in small infants where the detail obtained with cross-sectional imaging may be less than ideal. Cholangiography is only required if there is biliary dilatation secondary to central duct compression, or the diagnosis is rhabdomyosarcoma, in which case cholangiography is part of the diagnostic workup.
Resectability is determined initially by reviewing the preoperative imaging and then confirmed at laparotomy (see ‘Confirmation of Resectability’ section in this chapter). The essential requirements for resectability are removal of the disease with an appropriate margin while leaving a remnant with adequate volume that is well vascularised and has biliary drainage. Underlying chronic liver disease is uncommon in children coming to liver resection but critical to assessment of the future liver remnant (FLR). Nonlesional biopsy should be considered if there are indicators of underlying liver disease. The presence of portal hypertension is a contraindication to major resection, unless there is an extrahepatic cause. Rarely, underlying vascular anomalies that predispose to hepatocellular neoplasms, such as an Abernethy* malformation (see Chapter 22), may be discovered with the diagnostic imaging [9].
Following careful review of the imaging, the surgeon should formulate an operative strategy, pending confirmation at laparotomy.
In hepatoblastoma, transplantation should be considered in marginally operable or inoperable disease (complex PRETEXT 3, all PRETEXT 4) since primary transplantation provides better survival than salvage transplantation for incomplete resection or too aggressive resection leading to postresection liver failure [10].
21.4.2 Assessment of comorbidity
The issue of underlying liver disease is discussed above. Any patient being considered for liver resection also requires thorough assessment of cardiorespiratory and renal function, including anaesthetic assessment (routine) and specialist physician assessment (selective). Conditions associated with elevated right-sided heart pressures present a risk, not only from anaesthetic complications but also from increased bleeding during liver transection. Patients with prior exposure to doxorubicin require an echocardiogram, although this drug is no longer indicated in neoadjuvant treatment of standard-risk hepatoblastoma [11].
21.5.1 Incision, drains and closure
Laparoscopic hepatectomy is gradually becoming accepted as an alternative to open liver resection in selected adult patients [12], even for primary hepatic tumours [13]. There are case reports and small case series of laparoscopic liver resection emerging as well in the paediatric literature [14]. However, to date there have been no randomised controlled trials in adults or children comparing the risks and benefits of laparoscopic and open liver resection, and open resection remains a standard of care.
Infants and young children have a shallow hepatic fossa and malleable ribcage. Excellent exposure of the liver, including the suprahepatic region, is obtained via an upper abdominal transverse incision combined with bilateral costal margin retraction. The incision is placed approximately midway between the umbilicus and xiphisternum and shaped gently convex upward. Older children and adolescents, with a deeper hepatic fossa, more rigid ribcage and narrow costal margin, are best approached via an inverted L incision (right transverse subcostal with midline extension to the xiphisternum). This can be converted to a Mercedes incision for better access in exceptional circumstances.
The rationale for surgical drain placement after liver resection is early detection of bleeding and detection and control of bile leakage. There are also disadvantages of drains, including increased discomfort, infection risk and the need to replace fluid that might otherwise be resorbed physiologically. In recent years, there has been a move away from surgical drains in all kinds of abdominal surgery, and this is also supported by some [15, 16], although not all [17], uncontrolled studies in liver resection. It is perhaps surprising that there have been no randomised trials of prophylactic surgical drain use in liver resection. The author uses a drain selectively, based on assessment of risk at the end of surgery.
Deep wound closure is performed with an absorbable suture material such as polydioxanone or polyglyconate that will not impede subsequent growth. A subcuticular absorbable skin suture provides a satisfactory cosmetic result without the need for suture or staple removal.
21.5.2 Confirmation of resectability
The abdomen is explored for extrahepatic disease (in the case of cancer), including hepatic lymph nodes, and tissue sent for frozen section. The liver is examined by a combination of inspection, palpation and intraoperative ultrasound (IOUS) to determine the extent of the lesions, the relations to important structures and the size and quality of the FLR. The amount of residual liver required for recovery is in most cases two anatomical segments, provided these consist of normal healthy-appearing liver with an adequate blood supply, unimpeded hepatic venous outflow and good biliary drainage. If the liver is less than healthy, or if hepatic venous outflow is likely to be compromised by the resection, a correspondingly larger remnant volume is needed to avoid postoperative hepatic insufficiency (see Section 21.7). Determining where the limit lies in terms of FLR volume is one of the most difficult and important judgements in liver surgery. Preoperative evaluation is important and allows one to be prepared for possible contingencies, but in making the final decision about operability, there is no substitute for assessment by an experienced surgeon. Involvement of major biliary and vascular structures is not a contraindication if those structures can be resected to obtain a clear margin and suitably reconstructed.
Neoadjuvant chemotherapy may dramatically reduce hepatoblasoma tumour bulk but does not guarantee a tumour-free margin. Transplantation may a better option than attempting a heroic resection that leaves behind doubtful margins or an inadequate liver remnant [10]. Patients in whom the preoperative assessment raises any concerns about resectability should be managed in a transplant centre where either surgery can be undertaken with a backup graft available, or the patient listed immediately following exploration if found to be inoperable.
Some benign pathologies, such as mesenchymal hamartoma, can be managed by enucleation. Even when the liver architecture is severely distorted from mass effect, these lesions can usually be resected with preservation of essential vasculobiliary structures.
When confronted with the prospect of an inadequate FLR, especially if transplantation is not an option, two other possible techniques are available to increase FLR size prior to resection:
1. Portal vein embolisation (PVE) on the side of the liver to be resected (nearly always the right). Following PVE, portal flow is directed to the FLR and induces hypertrophy over the course of 3–4 weeks. The procedure is carried out radiologically, although surgical PV ligation is also described. No randomised controlled trials of PVE have been carried out, but case series and prospective case-control studies suggest a reduction in the risk of postoperative liver failure commensurate with the degree of hypertrophy observed [18, 19]. PVE has been in use for more than 15 years in adults [20], but there are no reports in paediatric liver resection. This may be because most paediatric tumours arise in an otherwise normal liver and tend to induce spontaneous hypertrophy due to mass effect, and because alternative options exist for hepatoblastoma.
2. Associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) is a more recently developed two-stage procedure; stage I consists of right portal vein ligation and parenchymal division, and stage II consists of completion hepatectomy 1–2 weeks later [21]. The addition of parenchymal division to surgical portal vein ligation seems to invoke a greater hypertrophy response than PVE alone, further reducing the risk of postoperative liver failure. However, this appears to come at the cost of increased morbidity and mortality, and many technical details, such the extent of partition during stage I of the procedure, are still being refined [22]. To date, no paediatric data are available regarding the ALPPS procedure.
21.5.3 Mobilisation of the liver
The extent of mobilisation is determined by the location and extent of resection. Left-sided resections may not require right lobe mobilisation, but right-sided resections usually require full mobilisation unless the resection is confined to inferior segments (Couinaud 5 and 6).
1. Left sided mobilisation – Divide the falciform ligament back to the confluence of the major hepatic veins, and the left triangular ligament as far medially as the left hepatic vein (the left phrenic vein enters the left hepatic vein anterolaterally and serves as a useful landmark). The gastrohepatic omentum can be divided from the left side of the hepatoduodenal ligament to the left hepatic vein. The accessory left hepatic artery, if present, lies between the leaves of the gastrohepatic ligament and may be divided with the ligament or preserved, depending on the resection.
2. Right sided mobilisation – Divide the falciform ligament back to the confluence of major hepatic veins, the right triangular ligament (which is short) and the inferior and superior leaves of the coronary ligament. The areolar tissue behind the bare area of the liver is divided until the vena cava is reached medially, rotating the right lobe progressively out of the hepatic fossa and keeping the dissection close to Glisson’s capsule.* The right adrenal gland may be fused with the liver capsule, and care is taken to avoid tearing the gland open. If it is not possible to separate the adrenal gland from Glisson’s capsule, the attached portion is encircled and separated by diathermy and the exposed portion of the adrenal gland oversewn for haemostasis.
3. Mobilising the liver from the retrohepatic cava is required for major right-sided resections, as well as resections involving the caudate lobe. In addition to the three major hepatic veins entering the IVC immediately below the diaphragm, there are numerous (up to 15) smaller, short hepatic veins entering directly into the cava from the adjacent dorsal liver. There is great variation to this anatomy, but a few common patterns are worth noting:
a. The largest of these venous tributaries are found inferiorly entering anteriorly or right lateral on the right side of the IVC (sometimes called accessory inferior right hepatic veins).
b. There are frequently one or more short, wide and sometimes bifid caudate branches entering the IVC to the left of the midline, about midway up the retrohepatic IVC. These branches are thin walled and easily damaged. The safest approach is exposure from both the right and left sides.
c. The anterior aspect of the IVC inferior to the sulcus between the right and middle hepatic veins seldom receives any tributaries. This anatomy is utilised to good effect for the passage of forceps and tape in the so-called ‘hanging liver technique’, or anterior approach to the IVC [23]. However, the anterior aspect of the IVC inferior to the confluence of middle and left hepatic veins usually receives several small caudate branches.
Full mobilisation of the liver from the retrohepatic IVC requires patient dissection. The dissection starts inferiorly with the liver retracted upwards and to the right (facilitated by first mobilising the left lobe) and dissecting upwards along the IVC, staying within the extra-adventitial plane of the IVC, outside Glisson’s capsule. Short hepatic veins are encircled, ligated and divided, suture ligating any short or tenuous branches. As mobilisation continues upwards, a broad band of fibrous connective tissue, known as the ligament of the IVC, bars access to the right side of the upper retrohepatic IVC. This band extends from the Glisson’s capsule on the dorsal aspect of segment 7 to the caudate lobe, and thus encloses the upper retrohepatic cava [24]. It sometimes consists of a fully formed bridge of liver parenchyma between segments 7 and segment 1, such that the upper retrohepatic cava is completely encircled by liver parenchyma. Regardless of whether there is liver parenchyma or just fibrous tissue, a large vein may be contained within the ligament. Division of the ligament is essential to expose the inferior aspect of the confluence of the right hepatic vein and IVC. Forceps are worked gently from inferior to superior, between the ligament laterally and cava medially. The ligament (or parenchymal bridge) is then divided, exposing the right hepatic vein–cava confluence.
On the left side, mobilisation of the liver away from the retrohepatic IVC requires division of the peritoneal layer posterolateral to Spiegel’s lobe of the caudate. This is facilitated by retracting the left lateral section to the right and the lesser curve of the stomach to the left, and dividing the peritoneum as it reflects from the caudate lobe to the posterior wall of the lesser sac. The left side of the retrohepatic IVC lies medial to this peritoneal layer. Any remaining caudate tributaries passing to the left side of the retrohepatic IVC are divided until meeting up with the right-sided dissection. Mobilisation is complete when the liver is attached to the IVC only by the three major hepatic veins.
21.5.4 Vascular control techniques
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