Remaining Liver Parenchyma Research Articles

Improving HCC Prognostic Models after Liver Resection by AI-Extracted Tissue Fiber Framework Analytics.

Despite advances in diagnostic and treatment technologies, predicting outcomes of patients with hepatocellular carcinoma (HCC) remains a challenge. Prognostic models are further obscured by the variable impact of the tumor properties and the remaining liver parenchyma, often affected by cirrhosis or non-alcoholic fatty liver disease that tend to precede HCC. This study investigated the prognostic value of reticulin and collagen microarchitecture in liver resection samples. We analyzed 105 scanned tissue sections that were stained using a Gordon and Sweet's silver impregnation protocol combined with Picric Acid-Sirius Red. A convolutional neural network was utilized to segment the red-staining collagen and black linear reticulin strands, generating a detailed map of the fiber structure within the HCC and adjacent liver tissue. Subsequent hexagonal grid subsampling coupled with automated epithelial edge detection and computational fiber morphometry provided the foundation for region-specific tissue analysis. Two penalized Cox regression models using LASSO achieved a concordance index (C-index) greater than 0.7. These models incorporated variables such as patient age, tumor multifocality, and fiber-derived features from the epithelial edge in both the tumor and liver compartments. The prognostic value at the tumor edge was derived from the reticulin structure, while collagen characteristics were significant at the epithelial edge of peritumoral liver. The prognostic performance of these models was superior to models solely reliant on conventional clinicopathologic parameters, highlighting the utility of AI-extracted microarchitectural features for the management of HCC.

Dorsal approach with Glissonian approach for laparoscopic right anatomic liver resections

BackgroundLaparoscopic anatomic hepatectomy (LAH) has gradually become a routine surgical procedure. However, how to expose the whole hepatic vein and avoid the hepatic vein laceration is still a challenge because of the caudate lobe, particularly in right hepatectomy. We adopted a dorsal approach combined with Glissionian appraoch to perform laparoscopic right anatomic hepatectomy (LRAH).MethodsTwenty patients who underwent LRAH from January 2017 to November 2018 were retrospectively analysed. Of these patients, seven patients underwent laparoscopic right hemihepatectomy (LRH group), seven patients who underwent laparoscopic right posterior hepatectomy (LRPH group), and six patients who underwent laparoscopic hepatectomy for segment 7 (LS7 group). The paracaval portion of caudate lobe could be transected firstly through dorsal approach and the corresponding major hepatic vein could be exposed from its root to the peripheral branches safely. Due to exposure along the major hepatic vein trunk, the remaining liver parenchyma could be quickly transected from dorsal to cranial side.ResultsThe mean age of the patients was 53.8 years and the male: female ratio was 8:12. The median operation time was 306.0 ± 58.2 min and the mean estimated volume of blood loss was 412.5 ± 255.4 mL. The mean duration of postoperative hospital stay was 10.2 days. The mean Pringle maneuver time was 64.8 ± 27.7 min. Five patients received transfusion of 2–4 U of red blood cells. Two patients suffered from transient hepatic dysfunction and one suffered from pleural effusion. None of the patients underwent conversion to an open procedure. The operative duration, volume of the blood loss, Pringle maneuver time, and postoperative hospital stay duration did not differ significantly among the LRH, LRPH, and LS7 groups (P > 0.05).ConclusionsDorsal approach combined with Glissonian approach for right lobe is feasible and effective in laparoscopic right anatomic liver resections.

The Significance of Microwave Ablation in the Treatment of Primary and Metastatic Liver Cancer

Extensive liver resection is the main method of treating patients with primary and metastatic liver cancer, which allows to achieve a significant prolongation of life. In patients with a reduced functional reserve of the liver or an insufficient volume of the remaining liver parenchyma, the applying of these interventions becomes impossible due to the increased risk of post-resection acute liver failure. One of the most modern and promising ways to overcome this obstacle is the use of minimally invasive methods of tumor destruction. We present clinical observations of the use of the microwave ablator: liver resection and percutaneous microwave ablation of colorectal cancer metastases to the liver. The presented experience demonstrates the justification for the use of microwave destruction of metastatic malignant tumors of the liver and demonstrates the possibilities of microwave thermal ablation therapy in patients who cannot be performed radical surgical treatment.

Cranial-Dorsal Approach Along the Middle Hepatic Vein Facilitating Laparoscopic Left Hemihepatectomy

The exposure and protection of middle hepatic vein (MHV) is crucial and difficult for anatomic laparoscopic left hemihepatectomy in the treatment of left hepatic tumor. 1, 2 The traditional caudal approach, which the liver is transected from the branch to the main trunk of MHV, is prone to damage the vessels. 3,4 The ventral approach is easy to expose the main trunk of MHV; however, the risk of vascular laceration caused by the caudal approach cannot be completely avoided, since the direction of endoscopic view and liver dissection are from the foot to the head side. We herein present a cranial-dorsal approach along the middle hepatic vein during laparoscopic left hemihepatectomy.The key point of the cranial-dorsal approach was the hepatic parenchyma transection from the root of MHV toward its distal branches. Briefly, left hepatic blood inflow was blocked, followed by the dissociation and transection from the left hepatic duct and vein. Along the direction of the main trunk of the MHV, the liver resection plane could be clearly exposed from the cranial and dorsal sides, and then the branches of the MHV were managed separately. Owing to the full exposure along the MHV trunk, the remaining liver parenchyma could be quickly transected to complete the anatomic left hepatectomy finally. This technique was performed in 10 patients who underwent laparoscopic left hemihepatectomy from March 2017 to December 2019. The median operative time was 188 min (range 150–265 min), and the intraoperative blood loss was 191 mL (range 100–300 mL). The median postoperative hospital stay was 6 days (range 4–8 days). No major postoperative complications or mortality was reported (Table 1). Cranial-dorsal approach along the MHV may be a feasible and effective technique during laparoscopic left hemihepatectomy, contributing to the process of anatomic left liver resection by full exposure and protection of hepatic veins.

Bronchobiliary fistula after hepatectomy: A case report and review of the literature.

Bronchobiliary fistula (BBF) is a rare complication following hepatectomy, and consists of an abnormal intercommunication between the biliary tract and bronchial tree. The management of this rare entity is challenging with limited current evidence to date on how to treat this condition. Herein, a case of BBF following a central hepatectomy and the successive steps of the management was presented. Fourteen months postoperatively, the patient presented to the Oncology Department complaining of new onset fever and expectoration. A computerized tomography scan revealed a BBF and the patient was subsequently referred to our department for further treatment. The surgical team decided that a further operation was required. Using the transabdominal approach, a communication between the initial intrahepatic collection and one inferior lobular bronchus was revealed. Transhiatal removal of fistula was performed with closure of the defect through the abdomen. There was no bile leak through the remaining liver parenchyma. Multidisciplinary management should be considered, taking into consideration the underlying pathology leading to this rare complication. Conservative treatment should be considered first, while surgical resection of the BBF remains an option when other therapies have failed. Surgeons should be aware of this rare complication bile duct injuries during hepatic operations can cause.

Treatment Strategies for Hepatocellular Carcinoma ⁻ a Multidisciplinary Approach.

Hepatocellular carcinoma (HCC) is the most common primary tumor of the liver and its mortality is third among all solid tumors, behind carcinomas of the lung and the colon. Despite continuous advancements in the management of this disease, the prognosis for HCC remains inferior compared to other tumor entities. While orthotopic liver transplantation (OLT) and surgical resection are the only two curative treatment options, OLT remains the best treatment strategy as it not only removes the tumor but cures the underlying liver disease. As the applicability of OLT is nowadays limited by organ shortage, major liver resections—even in patients with underlying chronic liver disease—are adopted increasingly into clinical practice. Against the background of the oftentimes present chronical liver disease, locoregional therapies have also gained increasing significance. These strategies range from radiofrequency ablation and trans-arterial chemoembolization to selective internal radiation therapy and are employed in both curative and palliative intent, individually, as a bridging to transplant or in combination with liver resection. The choice of the appropriate treatment, or combination of treatments, should consider the tumor stage, the function of the remaining liver parenchyma, the future liver remnant volume and the patient’s general condition. This review aims to address the topic of multimodal treatment strategies in HCC, highlighting a multidisciplinary treatment approach to further improve outcome in these patients.

FIRST RUSSIAN EXPERIENCE OF USING THE INTEGRATED SYSTEM OF LASER THERMOABLATION THERAPY IN THE TREATMENT OF METASTATIC LIVER CANCER

Extensive liver resections are the main method of treatment of patients with primary and metastatic liver cancer, which allows the noticeable prolongation of life. In patients with a reduced functional reserve of the liver or a missing volume of the remaining liver parenchyma, these interventions become impossible because of the increased risk of postresectional acute hepatic insufficiency. One of the most modern and promising ways to overcome this obstacle is the use of minimally invasive methods of tumor destruction. This article presents two observations of the clinical application of the laser ablator “Echolaser X4”: open laser ablation of the metastatic focus with subsequent atypical liver resection and percutaneous laser ablation of the metastasis of the neuroendocrine tumor into the liver. The presented experience testifies to the justification of using laser destruction of metastatic malignant liver tumors and demonstrates the possibilities of laser thermoablation therapy in patients who can not perform radical surgical treatment.

Pure laparoscopic right anterior sectionectomy for hepatocellular carcinoma with great vascular exposure.

Laparoscopic hepatectomy is a common procedure that has been reported frequently [1-3]. However, laparoscopic resection of tumors located in hepatic segments 5 and/or 8 remains a technically difficult procedure as it requires two transection planes [4]. Furthermore, there are a greater number of hepatic vein and glissonian pedicle branches that require a division as compared to other hepatectomy operations. In this report, we present a pure laparoscopic right anterior sectionectomy (RAS) for hepatocellular carcinoma (HCC). Preoperative imaging showed HCC (3cm× 4cm) in segment 5 [5]. After selective anterior segment inflow occlusion, transection lines were demarcated. Complete Pringle maneuver was performed for 15min intervals five times during hepatic parenchymal transection. The Cavitron Ultrasonic Surgical Aspirator was used for the transection of the hepatic tissue. Small hepatic vein branches along the middle and right hepatic veins and small glissonian pedicles were clipped, sealed and divided with EnSEAL (TM) (Ethicon). iDrive (TM) Ultra Powered Stapling device (Medtronic) was used for the division of tertiary glissonian pedicles. Hanging maneuver was performed for transection of remaining liver parenchyma after complete division of hepatic venous branches. The specimen was removed through the lower abdominal transverse incision using the endocatch bag. Jackson-Pratt drain was left in the operative field. All work was performed with IRB approval. Pure laparoscopic RAS for HCC was performed successfully without intraoperative complications or transfusions. The operation time was 300min, and the estimated blood loss was <200ml. On postoperative day 5, computed tomography scan showed well-perfused hepatic parenchyma. Pathology specimen confirmed 3.2cm×3cm×2.2cm HCC without involvement of surgical resection margins. The patient was discharged on postoperative day 7 without complications. Pure laparoscopic RAS is a feasible operative procedure in patients with tumors located in hepatic segments 5/8.

Colorectal Liver Metastases: A Never Ending Story.

See Article on Page 92-100 To improve the quality of life and outcomes for patients with colorectal liver metastases, we would like to emphasize some points. First, a colorectal multidisciplinary teams (MDT) should also include a specialized hepatobiliary MDT that has the expertise and the facilities to provide surgery for patients with liver metastases. The cases of patients being considered for treatment of hepatic metastases should be discussed at a multidisciplinary meeting in which the participants have experience in the management of liver metastases [1]. Second, traditional risk factors, as well as the indications and the contraindications, for a hepatic resection should be abandoned. The present principle as to resectability is that resection should be performed if all metastases, regardless of their sizes, number, locations and distribution, can be removed while leaving a sufficient remaining liver parenchyma [2]. As is known, the number of liver metastases, the spread of colorectal cancer to the lymph nodes, the maximum size of the metastases, the preoperative carcinoembryonic antigen level, the extrahepatic spread, and the use of a nonradical resection represent independent risk factors for recurrence [3,4]. Third, All resources should be used. Perioperative chemotherapy, portal vein embolization, a 2-stage hepatectomy, and local ablative therapies might improve outcomes.

Preoperative Portal Vein Embolization in the Combined Treatment of Malignant Liver Tumor

Aim. To improve the efficiency of preoperative portal vein mbolization as a method of prevention of postoperative liver failure after extensive resections. Material and Methods. The study included 30 patients with isolated liver tumors in whom advanced liver resection was planned. 33 embolizations were performed. In 23 observations mechanical embolization and scleroobliteration of the right branch of portal vein were made, oily chemoembolization and mechanical embolization of the right branch of the portal vein – in 10 cases. In 8 cases preoperative portal vein embolization was performed after oily chemoembolization of hepatic artery. 3 patients underwent repeated portal vein embolization due to insufficient hypertrophy of the remaining liver parenchyma. Results. Volume of remnant liver parenchyma increased by 41% after preoperative portal vein embolization on the average. In 5 cases insufficient volume of remnant liver was marked. The reasons of insufficient liver volume were partial recanalization of the embolized branches of the portal vein, the development of multiple intrahepatic portal collaterals (hemostatic spongeas as a embolic material in 3 cases), liver cirrhosis and 2 lines of previous chemotherapy in history (2 cases). In 3 patients repeated portal vein embolization using PVA particles and scleroobliteration with etoxisclerol foam was performed to achieve necessary hypertrophy. Extensive liver resection was performed in 24 patients. Postoperative mortality was noted in 2 cases. There was similar frequency of postoperative complications in patients with and without preoperative portal vein embolization. Conclusion. Preoperative portal vein embolization is a minimally invasive technique for increase of remnant liver volume prior to advanced liver resection without augmentation of postoperative complications rate. The results and technique may be improved (segment IV branch embolization, the use of foam scleroobliteration, mechanical occlusion combined with chemoembolization, combination of portal vein embolization and hepatic artery chemoembolization). Repeated embolization procedures can provide necessary liver hypertrophy in some cases

CLINICAL CASE OF PERFORMING A TWO-ST AGE LOVER RESECTION BY TYPE ALPPS IN PATIENT WHO PREVIOUSLY UNDERWENT ANATOMIC RESECTION OF THE RIGHT LOBE OF THE LIVER

Abstract: One of the variants for the surgical treatment of patients with bilobal liver metastases is to perform two-stage anatomic resections. Thus, at least in a quarter of the patients it is impossible to perform the second stage of intervention because of absence of hypertrophy of the remaining liver parenchyma or progression of disease during standby. The most modern and promising way of overcoming this obstacle is to perform the so-called ALPPS (Associating Liver Partition and Portal vein Ligation for Staged hepatectomy) or «in situ slit» liver resections. In this article we present a clinical case of performing a two-stage hepatectomy by type ALPPS in patients with metastatic colorectal cancer liver, who previously undergone the anatomic bisegmentectomy SVI-SVII. The present observation is the first in the available literature, evidence of justification perform repeated liver resections in patients with metastatic colorectal cancer and demonstrates the possibility of ALPPS techniques when performing extensive anatomical liver resections in patients who have undergone previous removal of the parenchyma of the right lobe.

Ultrasound segmental anatomy of liver

Anatomy of the liver does not correspond to its functional anatomy, and does not include parts of portal triad and hepatic venous system and therefore is not adequate in clinical practice, especially in terms of planning eventual surgical resection. Couinaud's classification of liver segments, modified by the Bismuth, is used for a rapid, ultrasound evaluation, in which the liver is divided into eight segments. The possibility of a functional-anatomic segmentation of the liver, based on respect for the system of portal triad and hepatic vein, undoubtedly gives ultrasonography great importance to the planning of possible resection of liver segments, affected by the pathological process, with sparing of the remaining liver parenchyma.

Study on virtual liver surgery planning applied to hepatic resection

To evaluate the impact of preoperative three-dimensional visualization and virtual liver surgery planning on hepatic resection. All relevant structures (livers, portal vein, hepatic veins, and tumors) were extracted from multislice CT scans of 142 cases treated from May 2007 to May 2009. By the liver surgery planning system software Liv 1.0, reconstruction and image analysis of the relevant structures was performed and virtual resections of liver were carried out. Data were correlated to intraoperative findings. (1) Three-dimensional visualization revealed the spatial relationship of tumors to the intrahepatic vascular system, thus giving impressions how the neoplasms were situated. Virtual tumor resections corresponded to the intraoperative findings. (2) With the planning, an intended resection could be performed virtually and optimal identification of resection margins could be achieved. The ischemia and congestion territory within the remaining liver parenchyma could be calculated. Simulation resections could avoid liver parenchyma over resection and maintain a sufficient amount of liver tissue to sustain hepatic function. Virtual simulations of tumor resection were used successfully to plan of surgical procedures in the hepatic tumors. Hepatectomy was performed in 29 cases after virtual tumor resections but seemed impossible with conventional CT scan. Resection plans of 92 cases were optimized after virtual resections. (3) The mean liver volume of patients with primary hepatocellular carcinoma measured by the software and the real resected was (477 +/- 223) ml and (451 +/- 209) ml respectively. Comparison by means of linear regression analysis between volume measurement on the software and the real resected showed a nearly ideal correlation coefficient (R = 0.922, P < 0.01). The mean error was 6.1%. The three-dimensional tumor visualization and virtual simulation of tumor resections of the software Liv 1.0 provide an important reference for a valuable planning of complex hepatic resections. It is not only benefit to improve the predictability and security of hepatectomy but also helpful to improve the success rate of complex hepatic resections.

Image segmentation of liver fibrosis

Quantitation of connective tissue versus parenchymal tissue compartments is important in assessment of fibrosis (scarring) and its progression in liver disease. This paper presents a two-step algorithm for quantifying fibrosis in liver biopsies stained with Sirius red. With this staining technique, collagen and cell nuclei appear similarly stained, whereas cytoplasm appears pale. The first step of the algorithm is to separate similarly stained areas occupied by collagen and hepatocyte nuclei. Since the total area of the combined collagen and cell nuclei is usually much smaller than the remaining liver parenchyma, a non-linear intensity mapping is applied to enhance the smaller cluster in order to match the larger one in both intensity and size. The second step is to differentiate the fibrotic areas usually having irregular shapes from hepatocyte nuclei that have relatively uniform size and have circular shape. The proposed algorithm has been applied to quantify the development of progressive fibrosis and its possible regression in liver biopsy specimens from patients with parenteral-induced liver injury undergoing intestinal transplantation.

Localized Hepatic Ischemia After Liver Resection

To prospectively assess the frequency, severity, and extension of localized ischemia in the remaining liver parenchyma after hepatectomy. Major blood loss and postoperative ischemia of the remnant liver are known factors contributing to morbidity after liver surgery. The segmental anatomy of the liver and the techniques of selective hilar or suprahilar clamping of the Glissonian sheaths permit identification of ischemia on the surface of the corresponding segments for precise section of the parenchyma. Incomplete resection of a segment, or compromised blood supply to the remaining liver, may result in ischemia of various extension and severity. Patients undergoing hepatectomy received enhanced computerized tomodensitometry with study of the arterial and venous phases within 48 hours after resection. We defined hepatic ischemia as reduced or absent contrast enhancement during the venous phase. We classified the severity of ischemia as hypoperfusion, nonperfusion, or necrosis. The extension of ischemia was identified as marginal, partial, or segmental. Factors that may influence postoperative ischemia were analyzed by univariate and multivariate analyses. One hundred fifty consecutive patients (70 F, 80 M, mean age 62 +/- 12 years) underwent 64 major and 81 minor hepatectomies and 5 wedge resections. We observed radiologic signs of ischemia in 38 patients (25.3%): 33 hypoperfusions (17 marginal, 12 partial, and 4 segmental), 3 nonperfusions (1 marginal, 1 partial, and 1 segmental), and 2 necroses (1 partial, 1 segmental). One patient with a segmental necrosis underwent an early reoperation. In all other cases, the evolution was spontaneously favorable. Postoperative peak levels of serum aspartate aminotransferase and alanine aminotransferase were significantly higher in patients with ischemia. Patients with ischemia had a significantly higher risk of developing a biliary leak (18.4% vs. 2.6%, P < 0.001). There was no correlation between liver ischemia and mortality (2%). None of the following factors were associated with ischemia after univariate and multivariate analysis: age, preoperative bilirubin level, liver fibrosis, malignant tumor, type of hepatectomy, surface of transection, weight of resected liver, Pringle maneuver, blood loss, and number of transfusions. Some form of localized ischemia after hepatectomy was detected in 1 of 4 of our patients. Its clinical expression was discreet in the large majority of cases, even if it might have been one of the underlying causes of postoperative biliary fistulas. Clinical observation is sufficient to detect the rare patient with suspected postoperative liver ischemia that will require active treatment.

Funktionsdiagnostik vor Leberresektion - teuer und ohne klinische Relevanz?

Hepatic failure after liver resection is a complication that is dreaded by surgeons and has a poor outcome. Inadequate functional reserve of the remaining liver parenchyma leads to the inability to regenerate and finally to the progression of liver failure. In order to predict the functional reserve of the remaining liver parenchyma, many different liver function tests have been established. Basis for most liver function assessments are metabolic liver functions such as cytochrome p450 dependent pathways or the extraction and biliary excretion of dye. Nuclear imaging of the liver parenchyma does not only allow visualisation of the liver but also accumulation of information on hepatocyte volume that might be a better predictor for the hepatic reserve and the regenerative capacity compared to the liver volume alone. However, to date no single method has been proven to be able to predict safe limits of resectability. If an underlying liver disease is excluded the resectability is mostly limited by volumetric analysis and technical feasibility of liver resection. In patients with underlying liver disease cirrhosis should be excluded. In case of liver cirrhosis, only Child-Pugh-Turcott A patients with normal bilirubin levels and without portal hypertension should be considered for liver resection.

Impact of Virtual Tumor Resection and Computer-Assisted Risk Analysis on Operation Planning and Intraoperative Strategy in Major Hepatic Resection

Currently, standard planning for hepatic resection is based on the schematic description of the functional anatomy of the liver according to Couinaud, and on the evaluation of 2-dimensional computed tomographic imaging of the liver. Recent developments in image-based computer assistance allow patients' individual functional liver anatomy to be computed from mathematical analysis of standard multidetector computed tomographic scans. An intended resection can be performed virtually under realistic anatomic conditions, and the influence of different resection planes on blood supply and drainage within the remaining liver parenchyma can be calculated by a computer-assisted risk analysis. We evaluated the impact of computer-assisted risk analysis on operation planning for major hepatectomies, in particular on extent of resection or need for vascular reconstruction. Prospective cohort study. Academic tertiary care referral center. Twenty-five consecutive patients admitted to the hospital for major hepatectomy, of whom 4 had tumors deemed unresectable by both methods. Two-dimensional computed tomography was used to calculate the volume of the future liver remnant with the intended resection line manually determined, and then the volume of the future liver remnant was calculated again by computer-assisted risk analysis as the remaining liver volume not being devascularized but having both portal venous blood supply and hepatic venous drainage. The difference between the remaining functional liver volumes calculated by the 2 methods. The deviation between liver volumes determined by 2-dimensional computed tomography and by computer-assisted risk analysis was less than 20% in 14 of 21 patients, between 20% and 30% in 3, between 30% and 40% in 2, and 41% and 43% in 1 patient each. The most extensive deviations were found in extended left hepatectomy or when left hepatectomy was combined with additional wedge resection in the right lobe. In 7 cases, all with a deviation greater than 20%, the results of computer-assisted risk analysis led to a change of operation planning with regard to the extent of resection (n = 3) or the need for vascular reconstruction (n = 4), although in 1 of these cases resection was not performed because of peritoneal carcinomatosis. Image-based computer assistance allows for areas at risk for devascularization or venous congestion to be identified and precisely calculated before resection. In selected cases with small liver remnants, operation planning may be improved substantially by preoperative computer-assisted risk analysis.

Effectiveness of preoperative selective portal vein embolization before extensive hepatic resection.

B ecause of the hepatotrophic properties of portal flow,' preoperative selective portal vein embolization (PSPVE) may be a safe method to induce atrophy of the embolized portion of liver before resection and a compensatory hypertrophy in the future remnant liver. This technique recently has become important in the preoperative management of patients who must undergo extensive liver resection,2-4 improving operability and avoiding life-threatening postoperative liver failure5~~ when there is a risk for insufficient remaining liver parenchyma after surgery. In clinical practice, this can occur in cases of: (I) a small left lobe and the need for extended or normal right hepatectomy; (2) major liver surgery in patients with liver function impaired by cirrhosis, severe cholestasis, or primary or postchemotherapeutic secondary fibrosis; and (3) severe fatty steatosis. The fact that PSPVE is well tolerated might expand its indications in the future to increase the safety

Liver resection using total vascular exclusion

Background: Total vascular exclusion (TVE) is a technique of liver resection that includes controlling both the suprahepatic and infrahepatic vena cava in addition to portal inflow at the time of parenchymal transection. We report a series of 61 liver resections in 60 patients using this technique. Methods: A retrospective review of 61 procedures in 60 patients using TVE between 1990 and 1997 was carried out. No patient had cirrhosis. Parameters analyzed included age, gender, diagnosis, procedure, operative time, clamp time, intraoperative transfusion requirements, postoperative laboratory studies, length of stay (intensive care unit, ward), mortality, and morbidity. Results: TVE was sustained hemodynamically in all patients. The mean age of the 34 men and 27 women was 56 years (± 15 years); 21% were older than 70 years. Eleven percent of the patients had benign lesions; 70% of the malignant tumors were metastatic. Seventy-five percent of the procedures were major or extended lobectomies. The mean operative and clamp times were 330 ± 83 and 39 ± 13.2 minutes, respectively; 68% had clamp times of <45 minutes. The mean intraoperative red blood cell units was 1.45 ± 1.93, with a range of 0 to 8 units; 48% required no transfusion and 80% received 2 units or less. There was 1 perioperative death for a mortality rate of 1.6%. The morbidity rate was 36%, which included 4 patients with postoperative liver dysfunction. Complications were not associated with transfusion but with clamp times exceeding 45 minutes. Liver dysfunction occurred with clamp times more than 60 minutes, particularly if the remaining liver parenchyma was histologically abnormal or the remnant was small. Conclusions: TVE is hemodynamically safe, even in patients older than 70 years. Blood loss during parenchymal transection is minimal; mortality and morbidity are low. The optimal clamp time is less than 45 minutes. Liver dysfunction is associated with clamp times exceeding 1 hour, particularly if the remaining parenchyma is abnormal or small. (Surgery 1998;124:807-15.)

Letter: Bile duct adenomatosis of the liver.

To the Editor. —Careful examination of the liver is a fundamental part of an exploratory laparotomy. Hepatic pathology is predictable by abnormal preoperative laboratory, roentgenographic, or isotopic studies. Recently, during an exploratory laparotomy for duodenal obstruction, we were unexpectedly confronted with an unusual liver lesion, not immediately recognizable. The liver was peppered with small, tan-green, subcapsular nodules, resembling metastases that frozen section showed to be bile duct adenomatosis. This rare, benign entity appears microscopically as multiple multilocular cystic masses lined by cuboidal cells. These clusters of dilated ducts are contained in fibrous stroma and are benign-appearing. Except for mild distortion by these adenomas, the remaining liver parenchyma appears normal. 1 Most feel bile duct adenomatosis is developmental, rather than inflammatory, obstructive, or neoplastic in cause. It has been proposed that the liver is derived from two anlage, one giving rise to the liver parenchyma and intralobular bile canaliculi and the