Liver resection: Hepatic segmentectomy

Introduction *

* Note that resection of segments II and III (left lobectomy) in this text is described as a major resection in Chapter 5 .

Segmental resection conserves functional liver parenchyma and minimizes the physiologic impact of liver resection. This is of particular benefit in a cirrhotic patient with impaired hepatocellular function. Segmentectomy may be regarded as a unisegmentectomy, when one segment is removed, or as a plurisegmentectomy, when two or more segments are excised. More commonly performed segmental resections include resection of segment I; resection of segment IV; and segmentectomy to remove segments IV, V, and VI ( Figs. 6.1 and 6.2 ). Central hepatic resection comprising resection of segments IV, V, and VIII is being increasingly performed, and this may be combined with resection of segment I, the latter operation being particularly indicated in some patients with hilar cholangiocarcinoma. Resection of segments VI and VII is, in effect, a posterior right sectorectomy, and resection of segments V and VIII is an anterior right sectorectomy.

Resection of segment IV is of value in the management of malignant lesions occupying only the quadrate lobe. Carcinoma of the gallbladder is a special case because the organ lies between segments IV and V of the liver. Resection for gallbladder cancer should involve, at a minimum, removal of segments IVb and V. Resections of segments II or III ( Fig. 6.3 ) are less frequently performed.

Segmentectomy I (caudate resection)

The procedure may be required as an isolated caudate lobe resection ( ) or as a caudate resection combined with major hepatectomy ( ). The anatomy of the caudate lobe and its close proximity to major vascular structures make resection difficult.

Anatomy

The caudate lobe (segment I) is the dorsal portion of the liver posteriorly and embraces the retrohepatic inferior vena cava (IVC). The lobe lies between major vascular structures: the IVC posteriorly and the portal triad inferiorly and the IVC and the middle and left hepatic veins superiorly ( Figs. 6.4 and 6.5 ). The anatomy is fully described in Chapter 1 .