Intraoperative liver steatosis characterization using diffuse reflectance spectroscopy.

BACKGROUND: Liver steatosis is associated with poor outcome after liver transplantation and liver resection. There is a need for an accurate and reliable intraoperative tool to identify and quantify steatosis. This study aimed to investigate whether surface diffuse reflectance spectroscopy (DRS) measurements could detect liver steatosis on humans during liver surgery. METHODS: The DRS instrumentation setup consists of a computer, a high-power tungsten halogen light source and two spectrometers, connected through a trifurcated optical fiber to a hand-held probe. Patients scheduled for open resection for liver tumors were considered for inclusion. Multiple DRS measurements were performed on the liver surface after mobilization. RESULTS: In total, 1210 DRS spectra originated from 38 patients, were analyzed. When applying the data to an analytical model the volumetric absorption ratio factor of fat and water specified an explicit distinction between mild to moderate, and moderate to severe steatosis (p < 0.001). There were significant differences between none-to-mild and moderate-to-severe steatosis grade for the following parameters: reduced scattering coefficient (p < 0.001), Mie to total scattering fraction (p < 0.001), Mie slope (p = 0.003), lipid/(lipid + water) (p < 0.001), blood volume (p = 0.044) and bile volume (p < 0.001). CONCLUSION: This study shows that it is possible to evaluate steatosis grades with hepatic surface diffuse reflectance spectroscopy measurements.

The impact of neoadjuvant chemotherapy on skeletal muscle depletion and preoperative sarcopenia in patients with resectable colorectal liver metastases.

BACKGROUND: Preoperative skeletal muscle depletion or sarcopenia has been suggested to predict worse outcome after resection of colorectal liver metastases. The aim of the present study was to investigate the impact of neoadjuvant chemotherapy on preoperative skeletal muscle mass prior to liver resection. METHODS: Patients operated with liver resection for colorectal liver metastases between 2010 and 2014 were retrospectively reviewed. Muscle mass was evaluated by measuring muscle area on a cross-sectional computed tomography image at the level of the third lumbar vertebra, and normalized for patient height, presenting a skeletal muscle index. RESULTS: Preoperative skeletal muscle mass was analysed in 225 patients, of whom 97 underwent neoadjuvant chemotherapy. In total 147 patients (65%) were categorized as sarcopenic preoperatively. Patients receiving neoadjuvant chemotherapy decreased in skeletal muscle mass (decrease by 5.5 (-1.1 to 11) % in skeletal muscle index, p < 0.001). Patients with muscle loss >5% during neoadjuvant chemotherapy were less likely to undergo adjuvant chemotherapy than others (68% vs 85%, p = 0.048). A >5% muscle loss did not result in worse overall (p = 0.131) or recurrence-free survival (p = 0.105). CONCLUSION: Skeletal muscle mass decreases during neoadjuvant chemotherapy. Skeletal muscle loss during neoadjuvant chemotherapy impairs the conditions for adjuvant chemotherapy.

Diffuse Reflectance Spectroscopy for Surface Measurement of Liver Pathology.

BACKGROUND: Liver parenchymal injuries such as steatosis, steatohepatitis, fibrosis, and sinusoidal obstruction syndrome can lead to increased morbidity and liver failure after liver resection. Diffuse reflectance spectroscopy (DRS) is an optical measuring method that is fast, convenient, and established. DRS has previously been used on the liver with an invasive technique consisting of a needle that is inserted into the parenchyma. We developed a DRS system with a hand-held probe that is applied to the liver surface. In this study, we investigated the impact of the liver capsule on DRS measurements and whether liver surface measurements are representative of the whole liver. We also wanted to confirm that we could discriminate between tumor and liver parenchyma by DRS. MATERIALS AND METHODS: The instrumentation setup consisted of a light source, a fiber-optic contact probe, and two spectrometers connected to a computer. Patients scheduled for liver resection due to hepatic malignancy were included, and DRS measurements were performed on the excised liver part with and without the liver capsule and alongside a newly cut surface. To estimate the scattering parameters and tissue chromophore volume fractions, including blood, bile, and fat, the measured diffuse reflectance spectra were applied to an analytical model. RESULTS: In total, 960 DRS spectra from the excised liver tissue of 18 patients were analyzed. All factors analyzed regarding tumor versus liver tissue were significantly different. When measuring through the capsule, the blood volume fraction was found to be 8.4 ± 3.5%, the lipid volume fraction was 9.9 ± 4.7%, and the bile volume fraction was 8.2 ± 4.6%. No differences could be found between surface measurements and cross-sectional measurements. In measurements with/without the liver capsule, the differences in volume fraction were 1.63% (0.75-2.77), -0.54% (-2.97 to 0.32), and -0.15% (-1.06 to 1.24) for blood, lipid, and bile, respectively. CONCLUSION: This study shows that it is possible to manage DRS measurements through the liver capsule and that surface DRS measurements are representative of the whole liver. The results are consistent with data published earlier on the combination of liver chromophores. The results encourage us to proceed with in vivo measurements for further quantification of the liver's composition and assessment of parenchymal damage such as steatosis and fibrosis grade.

Liver-first strategy for synchronous colorectal liver metastases - an intention-to-treat analysis.

BACKGROUND: The liver-first strategy signifies resection of liver metastases before the primary colorectal cancer. The aim of the present study was to compare failure to complete intended treatment and survival in liver-first and classical strategies. METHODS: All patients with colorectal cancer and synchronous liver metastases planned for sequential radical surgery in a single institution between 2011 and 2015 were included. RESULTS: A total of 109 patients were presented to a multidisciplinary team conference (MDT) with un-resected colorectal cancer and synchronous liver metastases. Seventy-five patients were planned as liver-first, whereas 34 were recommended the classical strategy. Twenty-six patients (35%) failed to complete treatment in the liver-first group compared to 10 patients in the classical group (P = 0.664). Reason for failure was most commonly disease progression. A total of 91 patients had the primary tumor resected before the liver metastases of which 67 before referral and 24 after allocation at MDT. Median survival after diagnosis in this group was 60 (48-73) months compared to 46 (31-60) months in the group operated with liver-first strategy (n = 49), (P = 0.310). DISCUSSION: Up to 35% of patients with colorectal cancer and synchronous liver metastases do not complete the intended treatment of liver and bowel resections, irrespective of treatment strategy.

Incisional hernia after open resections for colorectal liver metastases - incidence and risk factors.

BACKGROUND: Incisional hernia is one of the most common complications after laparotomy. The aim of this retrospective study was to investigate incidence, location and risk factors for incisional hernia after open resection for colorectal liver metastases including the use of perioperative chemotherapy and targeted therapy evaluated by computed tomography. METHODS: Patients operated for colorectal liver metastases between 2010 and 2013 were included. Incisional hernia was defined as a discontinuity in the abdominal fascia observed on computed tomography. RESULTS: A total of 256 patients were analyzed in regard to incisional hernia. Seventy-eight patients (30.5%) developed incisional hernia. Hernia locations were midline alone in 66 patients (84.6%) and involving the midline in another 8 patients (10.3%). In multivariate analysis, preoperative chemotherapy >6 cycles (hazard ratio 2.12, 95% confidence interval 1.14-3.94), preoperative bevacizumab (hazard ratio 3.63, 95% confidence interval 1.86-7.08) and incisional hernia from previous surgery (hazard ratio 3.50, 95% confidence interval 1.98-6.18) were found to be independent risk factors. CONCLUSIONS: Prolonged preoperative chemotherapy and also preoperative bevacizumab were strong predictors for developing an incisional hernia. After an extended right subcostal incision, the hernia location was almost exclusively in the midline.