This was an retrospective observational study for a series of patients underwent hepatectomy for benign or malignant hepatobiliary diseases, from July 1st, 2006 to September 1st, 2016 at the Department of General Surgery and Transplantation, Chongqing Medical University, China. Indications for resection are shown in Table 1. The patients requiring primary hepatectomy were considered eligible for entry into the study upon meeting the following inclusion criteria: no severe sepsis; no steroid or immunosuppressive medication administration. Patients who underwent a liver biopsy only were excluded. All the hepatectomies information including preoperative and intraoperative parameters were stored in the medical records, like demographic data, the clinical details of all the cases, preexisting comorbidities, etc. Following institutional review board approval, we retrospectively reviewed the electronic medical records of all this patients by investigators who had undergone our specific training. Patient background demographics included age, sex, previous major abdominal surgery, and comorbidities. Preoperative variables analyzed included diagnoses, American Society of Anesthesiology classification (ASA), and laboratory values (bilirubin, albumin, creatinine, platelet count). Intraoperative data were obtained from the operative note and the anesthesia record and included duration of operation and anesthesia, operating time, portal triad clamp time (pringle time), estimated blood loss (EBL), intraoperative blood transfusion, etc. The postoperative variables analyzed included nasogastric tube stay, parenteral nutrition duration, complications (any), hospital length of stay (LOS), intensive care unit (ICU) admission, mortality and necessity for re-operation.
The formal preoperative evaluation included a thorough preoperative history and physical examination, liver function tests, tumor markers measurement, routine chest x-ray film, routine cardiorespiratory evaluations, abdominal ultrasound, abdominal computed tomography (CT) scan and/or magnetic resonance (MR), in all cases. According to the Couinaud’s classification, anatomic resectability was evaluated in which the lesion(s) are completely anatomically removed on the basis of tolerable functional reserves, including segmentectomy, sectionectomy, hemihepatectomy, and extended hemihepatectomy. Nonanatomic partial resection was defined as a limited resection. According to the preference and experience of the attending surgeon, the surgical team determined the type of procedure for all the patients. To decrease the risk of postoperative liver failure, compensatory hypertrophy of the estimated remnant liver were induced through portal vein embolization (PVE) 3 to 6 weeks before liver resection when the volume of the future remnant liver was 25% or less in healthy livers and 40% or less in chronic hepatitis or cirrhosis livers.
Patients undergoing operation were set in the Trendelenburg position and explored through right or bilateral subcostal incision. All patients underwent a complete abdominal exploration and intraoperative ultrasound. To prevent venous hemorrhage, the central venous pressure was maintained below 5 cm H2O in all hepatectomies.
Liver resection was performed with an ultrasonic dissector (Ethicon Inc., Somerville, NJ). Major portal triads and hepatic veins were carefully exposed with the hook spatula Vessels greater than 2 mm in diameter were ligated or sutured with nonabsorbable sutures. Vessels less than 2 mm in diameter were coagulated with the bipolar cautery. Hemihepatic vascular occlusion, selective portal triad clamping and pringle maneuver were arbitrarily chosen alone or in combination with 15 minutes of occlusion alternated with 5 minutes of reperfusion.
The segmental resection was performed anatomically for one or more segments: five segments, extended hepatectomy; four segments, lobectomy (right hepatectomy); three segments, left hepatectomy (lobectomy), central hepatectomy; two segments, left lateral segmentectomy, right anterior or posterior sectorectomy; one segment, a wedge resection. Bilobar resections were considered as resection of segments from both the left and right hemilivers. An enucleation was defined zero segments resected. An abdominal drain was given routinely after hepatic resection.
Following operation, patients were not routinely admitted to the intensive care unit. A abdominal drain tube was usually placed during the operation, and routinely removed 3 days after hepatectomy. When the perioperative hemoglobin value fell below 8 g/L, blood transfusions were carried out. Abnormality of coagulation parameters were the indication for Fresh frozen plasma (FFP) transfusions, and intravenous albumin was given for patients with hypoalbuminemia. A broad-spectrum antibiotic was given routinely for 3 d. Oral feeding was restored when the bowel sounds returned and postoperative parenteral nutrition was administered when necessory.
Operative mortality was defined as any death resulting from the operation during the postoperative hospital stay. Postoperative morbidity included all the complications derived from the liver resection or associated procedure. Liver-specific complications commonly encountered after major liver procedures were assessed, including liver failure, ascites, bile leakage. Other complications happened were also recorded, like wound infection or dehiscence, intra-abdominal infection, postoperative hemorrhage, small bowel occlusion, subphrenic abscess, bronchopneumonia, and so on.
Preoperative, operative and postoperative variables were expressed as the means ± SD for continuous data and as numbers with percentages for categorical data. The association of variables with postoperative complications were evaluated using the chi-square test or Fisher exact test for categorical variables and the Student t-tests or rank sum test for continuous variables, when appropriate, respectively. Variables with statistical significance at the 0.10 level in univariable analysis were considered for multivariable analysis to determine the predictive value of the risk factors, which was performed by means of logistic regression. All statistical analyses were performed using the SPSS statistical package (version 17.0, SPSS Inc, Chicago, IL), and statistical significance was accepted at a two-tailed P value <0.05.