New techniques in liver surgery

Abstract: The development of liver surgery has a long history and through the years, much knowledge has been gathered concerning various aspects of the liver. The exploration and understanding of liver anatomy and liver regeneration and development of surgical techniques are important landmarks. Liver surgery today is a demanding field in which accumulated knowledge has fused with modern perioperative care to the benefit of the patients. In recent years simultaneous developments in radiological liver imaging, chemotherapeutic regimens and ablative treatment options further increased our ability to treat patients with liver disease. Liver surgery is the only treatment that can offer the patients long term survival or cure from malignant liver disease, but new treatment options are being developed and introduced in the clinic. To ensure patient safety these techniques have to be experimentally evaluated. Two rapidly expanding techniques are Radio Frequency Ablation and laparoscopic liver surgery. The aim of this study was to evaluate recognised risks during Radio Frequency Ablation (bile duct injury caused by heat), and laparoscopic liver surgery (carbon dioxide emboli). To give an overview of liver surgery in Sweden, Paper I is a registry study where liver surgery in Sweden recent years is described. All patients operated by liver resection in Sweden during 1987-1999 were included from the Inpatient Registry. Additional data were collected from the Swedish Cancer Registry and the Cause of Death Registry. Analyses of the patients, indications, mortality and causes of death are presented. In Sweden, 21 persons per million and year have been operated on and the patient selection criteria have probably been strict. Paper II is an animal experimental study evaluating a new technique for bile duct protection during Radio Frequency Ablation. With this technique, called intraductal cooling, cooled saline is infused in the bile ducts and supposedly protects them from heat injury. A protective effect was not proved in this study but the technique has been tested in patients with promising results, and it may need to be evaluated further. Importantly, we observed no negative effect of the cooling procedure on the ability of the Radio Frequency Ablation procedure to create the desired heat necrosis in the target tissue. Paper III and IV are animal experimental studies and focus on laparoscopic liver surgery. During pneumoperitoneum with carbon dioxide and liver parenchymal transection, embolisation to the pulmonary circulation is a recognised risk. Emboli may theoretically increase the morbidity among the patients. In paper III we have demonstrated changes in cardiopulmonary circulation persisting for hours after an experimental embolisation, an observation not earlier reported. In Paper IV we found differences in the risk of such emboli when different devices were used during laparoscopic parenchymal liver transection in pig. Influence on blood gases was apparent and indicates negative influence on the pulmonary gas exchange. The findings in Paper III and IV have clinical implications and have to be further evaluated. In conclusion, we have pointed out that liver surgery is relatively infrequent in Sweden and that future expansion is probably. The new techniques we evaluated are feasible but have recognised risks, confirmed and further described in this study. As we maximise the potential of the techniques, patient safety must have the highest priority.