Liver tissue characterization and influence of chemotherapy in liver surgery

Background & Aims: Primary liver cancer is the second most common cause of death from cancer worldwide. In the western world, the majority of liver malignancies consist of colorectal metastases. Liver resection is the primary treatment for cure in liver tumor disease. Hepatic injuries such as steatosis, steatohepatitis, fibrosis and sinusoidal obstruction syndrome, which could be a consequence of chronic liver disease and preoperative chemotherapy treatment, has negative impact on liver surgery. There is a need for an intraoperative tool for identification and quantification of these forms of liver damage. The general aim of this thesis was to evaluate methods for intraoperative liver parenchyma characterization and investigate if liver damage could be detected with these methods. In addition, the influence of chemotherapy on liver regeneration and incisional hernia incidence was investigated. Patients & methods: In study I, intraoperative sidestream dark-field imaging microcirculation measurements were performed on 40 patients before and after liver resection. In study II, intraoperative laser speckle contrast imaging measurements of liver microcirculation were performed on 10 patients. In study III, ex vivo diffuse reflectance spectroscopy measurements on excised liver tissue from 18 patients were performed. In study IV, intraoperative surface diffuse reflectance spectroscopy measurements were performed on 40 liver tumor patients. In study V, radiological liver volume measurements on 74 patients operated with a major liver resection were performed. In study VI, 256 patients’ computed tomography scans were reviewed for the presence of incisional hernia. Results & Conclusions: Liver resection leads to an increase in red blood cell velocity in the sinusoids. Patients with liver parenchymal damage have higher red blood cell velocity, lesser functional sinusoidal density and larger sinusoidal diameter. Laser speckle contrast imaging can potentially be used to achieve non-contact intraoperative hepatic microcirculation measurements but problems with movement artifacts need to be resolved. Surface diffuse reflectance spectroscopy measurements are descriptive for the entire liver and it is possible to perform measurements across the liver capsule. Liver surface diffuse reflectance spectroscopy measurements enable intraoperative steatosis grade evaluation with explicit distinction between mild-to-moderate and moderate-to-severe steatosis. Volume regeneration after a major liver resection is negatively affected by preoperative chemotherapy treatment in patients with colorectal liver metastases. The time interval between the ending of chemotherapy and operation is crucial for the power of this impact. Incisional hernia location after an extended right subcostal incision is almost exclusively in the midline. Risk factors for incisional hernia are prolonged preoperative chemotherapy, preoperative bevacizumab, and previous incisional hernia.