Umbilical Fissure Research Articles

Technical essentials, development, and evaluation of hepatic segmentectomy under regional vascular occlusion at hepatic hilum

Objective To summarize the experience of performing a variety of hepatectomies by occluding the branches of the hepatic artery (HA) and portal vein (PV) to the liver lobe, segment or subsegments in hilar H fissure for 344 patients in this hospital from 1987 to 2008. Methods (1) According to the size and location of the liver focus, major hepatectomy (66 cases), resection of separated hepatic subsegments (15 cases HS), resection of adjacent HS (216 cases) and resection of single HS (46 cases) were performed. (2) For left lateral HS, the left lateral inferior PV and left lateral superior PV originating from the lateral aspect of the left PV (LPV) were dissected, isolated and severed in umbilical fissure after the LHA was occluded. (3) For left medial HS, the left medial inferior PV and left medial superior PV originating from the medial aspect of the left PV were dissected、isolated and severed in umbilical fissure after the middle HA was occluded. (4) For right anterior HS, the right anterior PV was isolated and occluded in the anteior sulcus of the right longitudinal fissure (RLF) after the RHA behind the main hepatic duct was occluded. (5) For right posterior HS, the right posterior PV was isolated and occluded in the posterior sulcus of RLF after RHA was occluded.(6)The corresponding hepatic venous stem was protected as much as possible during the operation.Results (1) The operative mortality was 2.9% (10/344). Of these 10 patients, 8 died of liver failure and 2 bleeding. (2) Ten HCC patients (n=200) survived for 11～20 years, 4 for 7years, 19 for 5years and the 5-year survival rate was 18. 3% (33/180). For patients with hilar cholangiocarcinoma (n= 14), only 3 survived for 13, 6, 4 years, respectively. The patients with intrahepatic cholangiocarcinoma (n=13) survived for 1/2～3 years. Those with carcinoma of the gallbladder (n=12) survived for 1/2～1 year. All the patients with benign liver diseases (n=92) were cured. In 7 patients with intrahepatic lithiasis, the stones in other locations needed to be managed. Conclusion (1) Separated multiple hepatic subsegmentectctomy is an effective procedure to cure the compacted stones in 2～6 subsegmental hepatic ducts in both right and left lobes. (2) This procedure is reasonable, effective and of low cost for hepatectomy, worthy of being used because of the decrease in the ischemic liver mass and blood loss in operation, increase in the resectability of bulk liver cancer, alleviation of postoperative liver dysfunction and meeting the technical needs of a variety of hepatectomies for various liver diseases fulfilled by regional vascular occlusion at hepatic hilum instead of total hepatic afferent blood flow occlusion. Key words: Hepatectomy; Liver neoplasm; Hepatic hilum; Regional vascular occlusion

Venous outflow reconstruction with surgically reopened obliterated umbilical vein in domino liver transplantation

Venous outflow reconstruction with surgically reopened obliterated umbilical vein in domino liver transplantation

???Anatomic??? Right Hepatic Trisectionectomy (Extended Right Hepatectomy) With Caudate Lobectomy for Hilar Cholangiocarcinoma

The techniques of right hepatic trisectionectomy are now standardized in patients with hepatocellular or metastatic carcinoma, but not in those with hilar cholangiocarcinoma. Under preoperative diagnosis of hilar cholangiocarcinoma, 8 patients underwent "anatomic" right hepatic trisectionectomy with en bloc resection of the caudate lobe and the extrahepatic bile duct, in which the bile ducts of the left lateral section were divided at the left side of the umbilical fissure following complete dissection of the umbilical plate. Liver resection was successfully performed, and all patients were discharged from the hospital in good condition, giving a mortality of 0%. All patients were histologically diagnosed as having cholangiocarcinoma. The proximal resection margins were cancer-negative in 7 patients and cancer-positive in 1 patient. Four patients with multiple lymph node metastases died of cancer recurrence within 3 years after hepatectomy. One patient died of liver failure without recurrence 42 months after hepatectomy. The remaining 3 patients without lymph node metastasis are now alive after more than 5 years. Anatomic right hepatic trisectionectomy with caudate lobectomy can produce a longer proximal resection margin and can offer a better chance of long-term survival in some selected patients with advanced hilar cholangiocarcinoma.

Extended Right Hepatectomy with Total Caudate Lobe Resection and Biliary Tree Resection for a Large Colorectal Liver Metastasis Involving both the Right and Left Hepatic Lobes and the Umbilical Fissure: A Case Report

Very large right-sided liver tumors may grow up to the base of the umbilical fissure and involve the left hepatic duct and can occasionally reach the bile duct confluence. This kind of involvement has often been considered a contraindication to resection. We report a patient who presented with a large hepatic metastasis from colorectal cancer that reached the umbilical fissure and involved the left hepatic duct just above the bile duct confluence. An extended right hepatectomy including complete resection of caudate lobe was performed. We resected the left and common hepatic ducts, as well as both the entire hepatic and the proximal third of common bile duct. A long jejunal limb Roux-en-Y (45 cm) single-layer left intrahepatic hepaticojejunostomy was constructed. She is still well 14 months postoperatively. To the best of our knowledge, this is the first report of such a procedure employed for the treatment of a liver metastasis from colorectal cancer. Extended right hepatectomy including complete caudate lobe resection can be feasible even when the majority of the extrahepatic biliary system needs to be resected. Our approach probably offers the only chance to prevent early death from liver failure in these patients.

Study on computer‐aided diagnosis of hepatic MR imaging and mammography

It is well known that the liver is an organ easily attacked by diseases. The purpose of this study is to develop a computer‐aided diagnosis (CAD) scheme for helping radiologists to differentiate hepatic diseases more efficiently. Our software named LIVERANN integrated the magnetic resonance (MR) imaging findings with different pulse sequences to classify the five categories of hepatic diseases by using the artificial neural network (ANN) method. The intensity and homogeneity within the region of interest (ROI) delineated by a radiologist were automatically calculated to obtain numerical data by the program for input signals to the ANN. Outputs were the five pathological categories of hepatic diseases (hepatic cyst, hepatocellular carcinoma, dysplasia in cirrhosis, cavernous hemangioma, and metastasis). The experiment demonstrated a testing accuracy of 93% from 80 patients. In order to differentiate the cirrhosis from normal liver, the volume ratio of left to whole (LTW) was proposed to quantify the degree of cirrhosis by three‐dimensional (3D) volume analysis. The liver region was firstly extracted from computed tomography (CT) or MR slices based on edge detection algorithms, and then separated into left lobe and right lobe by the hepatic umbilical fissure. The volume ratio of these two parts showed that the LTW ratio in the liver was significantly improved in the differentiation performance, with in cirrhosis versus the normal liver . In addition, the application of the ANN method for detecting clustered microcalcifications in masses on mammograms was described here as well. A new structural ANN, so‐called a shift‐invariant artificial neural network (SIANN), was integrated with our triple‐ring filter (TRF) method in our CAD system. As the result, the sensitivity of detecting clusters was improved from 90% by our previous TRF method to 95% by using both SIANN and TRF.

First Successful Application of Side-to-Side Intrahepatic Cholangiojejunostomy to Biliary Obstruction after Living-Donor Liver Transplantation

Biliary anastomotic stenosis has been the most intractable problem after living-donor liver transplantation (LDLT) (1, 2). We first applied the side-to-side intrahepatic cholangiojejunostomy to biliary obstruction after LDLT. We here report our surgical techniques and the successful outcome of the procedure after 34 months. A 49-year-old woman was diagnosed with primary biliary cirrhosis 15 years ago. She developed liver failure with gastrointestinal bleeding caused by esophageal varices and subsequently underwent LDLT. The donor was the patient’s brother. The left lobe of the liver was harvested. Biliary reconstruction included a duct-to-duct anastomosis between the left hepatic duct of the donor and the common hepatic duct of the recipient. After anastomosis, a 5 F stenting tube was inserted toward the graft hepatic duct from the stump of the cystic duct. LDLT was successfully completed, and the patient postoperatively recovered without biliary complications. However, 3 months later, the patient occasionally experienced delayed bile leakage when the stenting tube was removed. Immediately, continuous drainage for the leak space was started. Subsequently, complete obstruction of the biliary anastomosis remained. Therefore, the percutaneous transhepatic bile drainage (PTBD) tube was inserted. Recanalization by radiologic interventions was attempted several times without success. In this case, cholangiography showed no anatomical anomaly and communication between the bile ducts of segment II, III, and IV at the occurrence of biliary obstruction as well as at the first transplant operation. Thus, the bile duct of the segment III was reconstructed by intrahepatic cholangiojejunostomy 6 months after LDLT. For this technique, which has been described previously, the bile duct is exposed by dissecting the umbilical fissure, and the division of liver tissue is not required (3). However, in the present patient, the bile duct of segment III was not markedly dilated (5 mm in diameter), and thus the process of its sufficient expo- sure for anastomosis posed some technical challenges. First, we confirmed the glisson of segment III by using intraoperative ultrasonography and inserted the marking needle toward its proximal site. Along this needle, the liver parenchyma was transected to the left of the round ligament. After the glisson was exposed sufficiently, the bile duct was identified by examining its bulge when the PTBD tube was pressurized. The bile duct was incised approximately 3 cm longitudinally and anastomosed side-to-side to the Roux-en-Y limb of the jejunum with a 6–0 PDS suture in an interrupted fashion. A 5 F biliary stenting tube was introduced toward the graft hepatic duct from the Roux-en-Y limb of the jejunum (Fig. 1, A and B). The patient remained well without biliary complications during the follow-up period of 34 months (Fig. 1C).FIGURE 1.: Successful treatment of delayed-onset biliary obstruction after left-lobe living-donor liver transplantation (LDLT) by side-to-side intrahepatic segment III cholangiojejunostomy. (A) Schematic view of the procedure. The bile duct of segment III is exposed and incised approximately 3 cm longitudinally. It is anastomosed side-to-side to the Roux-en-Y limb of the jejunum with a 6–0 PDS suture in an interrupted fashion. A 5 F biliary stenting tube is introduced toward the graft hepatic duct from the Roux-en-Y limb of the jejunum. (B) Operative field photograph after completion of the procedure. (C) Magnetic resonance cholangiopancreatography 32 months after the reoperation showing patency of the anastomosis.Originally, this technique was used as a palliative treatment for obstructive jaundice caused by tumor involvement of the hepatic hilum (4). Although conversion to Roux-en-Y hepaticojejunostomy is usually used in the management of biliary obstruction after duct-to-duct anastomo-sis, it is always accompanied by the risk of injury to the important hilus structures. As for the intrahepatic cholangiojejunostomy, the Longmire technique has been widely recognized. However, it requires partial hepatectomy and is sometimes followed by anastomotic stenosis, especially when a small intrahepatic bile duct is anastomosed end-to-side to the jejunum (5). In contrast, this technique has the following advantages. First, it avoids manipulation of the hepatic hilum. Second, the bile duct of segment III is superficially located and easily accessible, and thus the reoperation can be performed at the minimal expense and without hepatic sacrifice. Finally, side-to-side reconstruction offered a sufficient anastomotic size. However, further investigation is necessary to substantiate the value of this technique. Motohide Shimazu Tomotaka Akatsu Go Wakabayashi Minoru Tanabe Shigeyuki Kawachi Ken Hoshino Masaki Kitajima Department of Surgery Keio University School of Medicine Tokyo, Japan

肝臓MR画像と乳房X線写真のコンピュータ支援診断に関する研究

It is well known that the liver is an organ easily attacked by diseases. The purpose of this study is to develop a computer-aided diagnosis (CAD) scheme for helping radiologists to differentiate hepatic diseases more efficiently. Our software named LIVERANN integrated the magnetic resonance (MR) imaging findings with different pulse sequences to classify the five categories of hepatic diseases by using the artificial neural network (ANN) method. The intensity and homogeneity within the region of interest (ROI) delineated by a radiologist were automatically calculated to obtain numerical data by the program for input signals to the ANN. Outputs were the five pathological categories of hepatic diseases (hepatic cyst, hepatocellular carcinoma, dysplasia in cirrhosis, cavernous hemangioma, and metastasis). The experiment demonstrated a testing accuracy of 93% from 80 patients. In order to differentiate the cirrhosis from normal liver, the volume ratio of left to whole (LTW) was proposed to quantify the degree of cirrhosis by three-dimensional (3D) volume analysis. The liver region was firstly extracted from computed tomography (CT) or MR slices based on edge detection algorithms, and then separated into left lobe and right lobe by the hepatic umbilical fissure. The volume ratio of these two parts showed that the LTW ratio in the liver was significantly improved in the differentiation performance, with (25.6%±4.3%) in cirrhosis versus the normal liver (16.4%±5.4%). In addition, the application of the ANN method for detecting clustered microcalcifications in masses on mammograms was described here as well. A new structural ANN, so-called a shift-invariant artificial neural network (SIANN), was integrated with our triple-ring filter (TRF) method in our CAD system. As the result, the sensitivity of detecting clusters was improved from 90% by our previous TRF method to 95% by using both SIANN and TRF.

Biliary stricture resulting from radiofrequency ablation

An elderly man with cirrhosis secondary to hepatitis B presented with an asymptomatic 2-cm liver lesion. This lesion was hypervascular during the arterial phase of triphasic computed tomography (CT) scan of the liver with rapid washout. The lesion had the typical appearance of a hepatocellular carcinoma. Elevation of alpha fetoprotein was also noted. A biopsy was not performed. The patient had moderate decompensation of liver function (Childs' B) with a prolonged indocyanine green clearance, and therefore was not a candidate for hepatic resection. Percutaneous radiofrequency ablation (RFA) of the lesion was performed. The procedure was uncomplicated, with apparent complete ablation of the lesion. On follow-up imaging 6 months after ablation (Fig. 1), there was no evidence of recurrence; the ablation site in segment 3 (left of umbilical fissure) was evident. Of note, new dilatations of the segment 2/3 biliary radicals were noted. No evidence of malignant obstruction was identified on imaging. This stricture and dilation was thought to be the result of thermal injury as a consequence of the RFA procedure.

A modification of segment III intrahepatic cholangiojejunostomy

Segment III bypass can achieve excellent palliation in jaundiced patients with unresectable malignancy of the hepatic duct confluence. However, the long-term benefits are often offset by early morbidity and mortality associated with surgery. Bile leakage is a common postoperative complication. Several approaches to the segment III duct have been described. The “round ligament approach” identifies the segment III duct by following the round ligament into the recessus of Rex, in the umbilical fissure. It is the approach adopted by most units, including our own. The liver is often split to a depth of 5 to 6 cm to expose the duct. Fashioning an intrahepatic cholangiojejunostomy within the recess of the umbilical fissure can be technically difficult due to lack of space. We describe a modification of the round ligament approach, creating a long and tension-free cholangiojejunostomy, which we believe reduces the incidence of postoperative bile leakage.

Is cholangiography required for ex situ splitting of cadaveric livers?

Anomalous biliary anatomy is encountered frequently and, if not considered at the time of ex situ splitting of a cadaveric liver into left lateral segment and right lobe grafts, right-sided second-order ducts that enter the left system, or the segment IV duct, may be damaged, leading to biliary complications in the recipients. Bench cholangiography facilitates delineation of these anomalies, but if one considers the commonly encountered variations in biliary anatomy, in relation to the correct plane of division of the left hepatic duct (away from the hilum, close to the umbilical fissure), it is possible to avoid inadvertent injury to right-sided sectoral ducts. This approach, combined with careful probing of the ducts and absolute identification of the segment IV duct negates the contribution of cholangiography.

Management of the left hepatic duct during extended right hepatectomy

Extended right hepatic lobectomy involves the resection of segments IV to VIII and often includes resection of the caudate lobe (segment I). This resection is necessary to treat right-sided tumours that extend into segment IV. On occasion these tumours will extend to the umbilical fissure (Figure 1) and involve the left hepatic duct at the base of the fissure. This involvement has often been considered a contraindication to resection as mobilisation of tumour off the left duct is technically difficult and may result in a positive margin. Unrecognised damage to the duct may also present in the postoperative period with a biliary fistula. We report three patients who presented with massive right-sided tumours involving the left hepatic duct at the base of the umbilical fissure, on whom extended right hepatectomy was carried out in conjunction with resection and primary anastomosis of the left duct. Open in a separate window Figure 1. Line drawing illustrating a tumour lying in the base of segment IV.

Surgical anatomy of the left lateral segment as applied to living-donor and split-liver transplantation: a clinicopathologic study.

To evaluate intrahepatic vascular and biliary anatomy of the left lateral segment (LLS) as applied to living-donor and split-liver transplantation. Living-donor and split-liver transplantation are innovative surgical techniques that have expanded the donor pool. Fundamental to the application of these techniques is an understanding of intrahepatic vascular and biliary anatomy. Pathologic data obtained from cadaveric liver corrosion casts and liver dissections were clinically correlated with the anatomical findings obtained during split-liver, living-donor, and reduced-liver transplants. The anatomical relation of the left bile duct system with respect to the left portal venous system was constant, with the left bile duct superior to the extrahepatic transverse portion of the left portal vein. Four specific patterns of left biliary anatomy and three patterns of left hepatic venous drainage were identified and described. Although highly variable, the biliary and hepatic venous anatomy of the LLS can be broadly categorized into distinct patterns. The identification of the LLS duct origin lateral to the umbilical fissure in segment 4 in 50% of cast specimens is significant in the performance of split-liver and living-donor transplantation, because dissection of the graft pedicle at the level of the round ligament will result in separate ducts from segments 2 and 3 in most patients, with the further possibility of an anterior segment 4 duct. A connective tissue bile duct plate, which can be clinically identified, is described to guide dissection of the segment 2 and 3 biliary radicles.

The Glissonian approach of the hilum.

The detailed knowledge of the segmental anatomy of the liver has led to a rapid evolution in resectional surgery based on the intrahepatic distribution of the portal trinity (the hepatic artery, hepatic duct and portal vein). The classical intrafascial or extrahepatic approach is to isolate the appropriate branch of the portal vein, hepatic artery and the hepatic duct, outside the liver substance. Another method, the extrafascial approach, is to dissect the whole sheath of the pedicle directly after division of a substantial amount of the hepatic tissue to reach the pedicle, which is surrounded by a sheath, derived from Glisson's capsule. This Glissonian sheath encloses the portal trinity. In the transfissural or intrahepatic approach, these sheaths can be approached either anteriorly (after division of the main, right or umbilical fissure) or posteriorly from behind the porta hepatis. We describe the technique for approaching the Glissonian sheath and hence the hepatic pedicle structures and their branches by the intrahepatic posterior approach that allows early delineation of the liver segment without the need for ancillary techniques. In addition, the indications for the use of this technique in the technical and oncologic settings are also discussed.

The posterior intrahepatic approach to liver resection

Background Hepatic resectional surgery has rapidly evolved since the realisation of the segmental anatomy of the liver and the intrahepatic distribution of the portal trinity (the hepatic artery, hepatic duct and portal vein). This portal trinity is enveloped by a sheath, derived from Glisson's capsule. In the classical intrafascial or extrahepatic approach, the appropriate branch of the portal vein, hepatic artery and the hepatic duct is isolated outside the liver substance, whereas in the extrafascial approach the whole sheath of the pedicle is dissected, after division of a substantial amount of hepatic tissue. In the transfissural or intrahepatic approach, these sheaths can be approached either anteriorly (after division of the main, right or umbilical fissure) or posteriorly, from behind the porta hepatis, through the distal fissure. Methods We describe the technique of the intrahepatic posterior approach to the glissonian sheath, with its contained hepatic pedicle structures and branches. Results This technique allows early delineation of a liver segment, without the need for ancillary manoeuvres. Discussion The indications for the use of this technique in an oncological setting are also discussed.

Division of the left hemiliver in man--segments, sectors, or sections.

A major obstacle to coherent terminology for liver anatomy and resections has been that American and French anatomists have divided the left side of the liver through different planes. Couinaud divided the left hemiliver into "sectors" by a plane through the left hepatic vein. Healey and Schroy divided it into "segments" through the umbilical fissure. One anatomic justification for Couinaud's system of sectors is that the transverse portion of the left portal vein was said to terminate by dividing into the umbilical portion of the left portal vein and the vein to segment II. However, corrosion cast studies fail to consider the position of the ligamentum venosum, the structure defining the end of the transverse portion of the left portal vein. Therefore, it is uncertain whether the branch to segment II is a terminal branch of the transverse portion of the left portal vein or a branch of the first part of the umbilical portion. Ten cadaver livers were dissected to determine the position of the branch to segment II in relation to the ligamentum venosum. In all, the branch to segment II came off downstream to the ligamentum venosum, showing that it is a branch of the umbilical portion of the left portal vein. This study does not support the "sectoral" system of Couinaud on the left side of the liver. Division of the left side of the liver through the umbilical fissure as proposed by Healey is anatomically logical and fits well with common surgical resections.

Original extrahilar approach for hepatic portal revascularization and relief of extrahepatic portal hypertension related to later portal vein thrombosis after pediatric liver transplantation. Long term results.

Original extrahilar approach for hepatic portal revascularization and relief of extrahepatic portal hypertension related to later portal vein thrombosis after pediatric liver transplantation. Long term results.

Hilar and Intrahepatic Biliary Enteric Anastomosis

This article discusses the anatomy and surgical technique of high biliary enteric anastomosis for benign and malignant disease. Emphasis is placed on the approach to the left hepatic duct at the base of the liver and to the segment III duct within the umbilical fissure.

Hepatic Resection for Hepatolithiasis

To analyze the results of hepatic resection for hepatolithiasis. A retrospective study of case records of patients with hepatolithiasis undergoing hepatic resection. These patients had been followed up for 3 to 38 months. They were referred to Queen Mary Hospital, a tertiary referral center in Hong Kong. Of 172 patients with hepatolithiasis seen between January 1984 and December 1981, 63 patients underwent hepatic resection because the affected liver segments were destroyed by repeated infection (n = 51), multiple cholangitic liver abscesses were found in the affected liver segments (n = 9), or concomitant intrahepatic cholangiocarcinoma was diagnosed (n = 3). Left lateral segmentectomy was performed in 42 patients, left hepatic lobectomy in 15 patients, right hepatic lobectomy in one patient, and segmentectomy in five patients. Postoperative morbidity and mortality analysis. Contrary to hepatic resection in a normal liver, dissection to isolate inflow and outflow vasculature was difficult in 52% of cases owing to severe inflammatory fibrosis at the liver hilum, at the umbilical fissure, or at the junction of hepatic vein with inferior vena cava. The operative morbidity rate was 32% and the mortality rate was 2%. The majority of complications were wound infection, subphrenic abscesses, or biliary fistulas, which could be due to the presence of infected bile (85%) and liver abscesses (25%) in this disease. Statistical analysis of the preoperative hematological and biochemical variables and the amount of intraoperative blood loss could not identify any factor with significance in correlating with the development of postoperative complications. Stones recurred in 16% after a median follow-up of 47 months. Hepatic resection is a satisfactory treatment for hepatolithiasis. The postoperative septic complication rate is high and is an intrinsic problem related to liver resection in a septic condition.

Palliative operative procedures for carcinoma of the gallbladder

Gallbladder cancer afflicts predominantly women, the elderly, and persons with gallstones. Despite its producing symptoms of abdominal pain, nausea and vomiting, weight loss, jaundice, and anorexia, this disease remains difficult to detect. Even with contemporary imaging techniques, most gallbladder cancers escape diagnosis until the time of laparotomy. The aggressive character of this malignancy permits an overall 5-year survival rate of 3-5%. Although cures occur, the majority of operations performed for gallbladder cancer are for palliation. The objects of palliation include relief of pain, relief of jaundice, relief of intestinal obstruction, and the restoration of normal food intake. Resection of the tumor should be performed whenever possible; however, extensive operations including large liver resections and pancreaticoduodenectomy should be avoided in the presence of distant metastases. In the presence of large unresectable hilar masses, internal biliary bypass may relieve jaundice. Biliary-enteric anastomosis using the segment III duct exposed via the umbilical fissure may offer satisfactory relief of jaundice in selected cases.

Preoperative localization of focal liver lesions to specific liver segments: utility of CT during arterial portography.

The authors retrospectively studied 36 hepatic masses in 20 patients who underwent computed tomography during arterial portography (CTAP) and subsequent hepatic tumor resection. The authors used the right main and left main portal veins as landmarks for the transverse scissura, along with the hepatic veins, the gallbladder fossa, and the umbilical fissure to blindly predict the segmental location of each tumor confirmed at surgery. The right main and left main portal veins were found to be consistently near the middle sections through the liver. CTAP findings and surgical descriptions agreed on the primary segmental location of 33 of 36 focal lesions (92%) but disagreed on the extent of 11 of 36 lesions (31%). Further review of the CTAP scans of the 11 lesions revealed that the extent of the lesion was more correctly described at surgery in six masses and at CTAP in four masses; in one lesion, opposite margins of the same mass were correctly described at both surgery and CTAP. Since it may be difficult or impossible to localize deep hepatic lesions intraoperatively by means of palpation or inspection, CTAP is a helpful preoperative tool for determining the segmental location of lesions and for planning the surgical approach.