{"id":11288,"date":"2026-04-13T09:06:46","date_gmt":"2026-04-13T09:06:46","guid":{"rendered":"https:\/\/www.proefschriftmaken.nl\/portfolio\/toine-lodewick\/"},"modified":"2026-04-22T14:51:08","modified_gmt":"2026-04-22T14:51:08","slug":"toine-lodewick","status":"publish","type":"us_portfolio","link":"https:\/\/www.proefschriftmaken.nl\/en\/portfolio\/toine-lodewick\/","title":{"rendered":"Toine Lodewick"},"content":{"rendered":"","protected":false},"excerpt":{"rendered":"","protected":false},"author":8,"featured_media":12196,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"us_portfolio_category":[45],"class_list":["post-11288","us_portfolio","type-us_portfolio","status-publish","has-post-thumbnail","hentry","us_portfolio_category-new-template"],"acf":{"naam_van_het_proefschift":"MORE OR LESS","samenvatting":"Er is geen Nederlandse samenvatting beschikbaar. De Engelse samenvatting vind je <a href=\"https:\/\/www.proefschriftmaken.nl\/en\/portfolio\/toine-lodewick\/\">hier<\/a>.","summary":"Chapter 1 contains the introduction to this thesis and attempts to outline the problems addressed in this thesis. Firstly the complexity of the liver anatomy is described with its arterial and portal inflow and venous and bile outflow. These vascular structures and bile ducts separate the liver in eight segments. By respecting these segments during liver resections if possible, complication rates can be minimised. In this chapter also the most common resections and the considerations for such resections are debated. Moreover interventions such as portal vein embolisation, two-stage hepatectomy and the ALPPS procedure (associating liver partition and portal vein ligation in staged hepatectomy) are discussed as possible strategies when the anticipated remnant liver is initially too small. The most feared complication after liver resection is liver failure. Postresectional liver failure is difficult to predict and the current preoperative risk assessment does not seem sufficient. Liver volumetry options to assess remnant liver volume and function are debated. As volume of the liver reflects function to some point, this is seems a valid option in most standard cases. Liver function should however also be taken into account as patients with diminished liver function are prone for postresectional liver failure and volume does not always equal function. Many liver function tests have been investigated but to date a gold standard has not been found. Recently the LiMAx test has been developed which seems to give an accurate reflection of the metabolic function of the hepatocytes. Despite preoperative liver volumetry and liver function analysis, postresectional liver function still occurs which seems to indicate a more multifactorial aetiology and perhaps body composition is another important factor to deal with preoperatively.\n\nPart I OUTCOME AFTER LIVER RESECTION\n\nIn Chapter 2 we describe how over the years the indications for liver resection have changed. In the past, patients with colorectal cancer liver metastases were only offered surgical treatment according to limited indication criteria which meant a maximum number of 3 liver metastases, located in one liver lobe, without signs of extrahepatic disease and with an anticipated resection margin of 10 mm. These restricted criteria have been abandoned one by one. We compared outcome of patients with limited and extended criteria and were able to justify surgery in patients with extended criteria. As the disease burden was greater in the extended criteria group the operating time, major complication rate and the number of oncological incomplete (R1) resections were all significantly higher in the extended criteria group, but were still acceptable. Length of hospital stay and the number of readmissions were comparable. Disease-free and overall survival were significantly shorter in the extended criteria group. However with a 5 year survival rate of 33% and a median survival of 41 months, survival still seems twice as long as in patients treated with chemotherapy alone. Moreover, cure (disease-free survival >10 years) was still reached in 16% of patients.\n\nChapter 3 discusses the effects of postoperative morbidity on disease-free and overall survival after surgery for colorectal liver metastases. Two-hundred-sixty-six patient with colorectal cancer liver metastases operated on between 2000 and 2011 were included. Ninety-seven (37%) patients developed complications, 61 (23%) of whom had major complications (Dindo-Clavien \u2265 3a). The occurrence of major postoperative complications resulted in significantly decreased median disease-free survival from 17 months in patients without postoperative complications to 13 months in patients with major complications. Concerning overall survival, the differences seen between these two groups did not reach significance.\n\nIn Chapter 4 the influence of age on early postoperative outcome was investigated in a modern day cohort. Between 2005 and 2012 a total of 460 patients aged <60 or >70 underwent a hepatic resection in the University hospital Aachen or the Maastricht University Medical Centre. The median length of hospital stay was significantly longer in the older population (8 vs. 7 days). Liver related complications were comparable between the two groups. Pneumonia\u2019s however, were significantly more often observed in the group >70 years of age (8% vs. 2%) and 44% of the patients >70 with a pneumonia died due to pulmonary sepsis. Mortality rates for patients <60 and >70 were 1.9% and 5.6% respectively. This difference did not reach statistical significance. Morbidity and mortality rates in patients over 70 years of age seem acceptable but especially pneumonia\u2019s need to be prevented as much as possible, as this complication has a high association with postoperative mortality.\n\nIn Chapter 5 the results are presented of a study to validate the peak bilirubin criterion (>7.0mg\/dL or > 120 \u03bcmol\/L), as proposed by Mullen in 2007, for outcome after liver surgery. In the Maastricht University Medical Centre and the Royal Free London hospital 956 patients undergoing partial hepatectomy between 2005 and 2012 were included. Thirty-five patients met the peak bilirubin criterion at median day 19. Sensitivity for liver related 90-day mortality after major hepatectomy was 41.2%. Specificity was 94.6% and the positive predictive value was 22.6%. Peak bilirubin was however identified as the strongest independent variable for liver-related 90-day mortality. Since the peak bilirubin criterion is a relatively late and weak predictor for liver-related mortality, an earlier predictor is desirable.\n\nPart II OUTCOME AFTER LIVER RESECTION: VOLUMETRY AND FUNCTION\n\nIn Chapter 6 the outcomes are presented of an automated method for liver volumetry (Terarecon Aquarius iNtuition\u00ae) and a comparison of this method with manual delineation of liver contours, the gold standard. Two radiologists and two PhD candidates who focused on liver surgery assessed a total of 27 preoperative CT scans. Auto-segmentation of total liver volumetry, future remnant liver volume and calculation of the future remnant liver volume percentage was valid and accurate. Moreover this method turned out to be 3 times faster than manual segmentation.\n\nChapter 7 reports on liver regeneration after two surgical procedures for centrally located liver tumours. The decision for either a mesohepatectomy (central liver resection) or a trisectionectomy in such patients is mostly based on surgeon preferences. A mesohepatectomy saves liver tissue but two resection planes have to be made, with an increased risk to be irradical. On the other hand the risk of postresectional liver failure after a trisectionectomy might withhold a surgeon from such a strategy. Between 2002 and 2012, 9 patients who underwent an anatomical mesohepatectomy and 8 patients operated according to a right trisectionectomy procedure were included. We provided another argument in favour of the mesohepatectomy approach in such patients as the liver regenerates to its original volume after a mesohepatectomy while it already ceases at 82% regeneration after trisectionectomies. In case of recurrence a second operation seems more likely to be feasible in patients that underwent a mesohepatectomy.\n\nChapter 8 evaluates the effects of age on liver function after partial hepatectomy. All patients between 2011 and 2013 who underwent a preoperative LiMAx liver function test, which is a methacetin breath test measuring the liver specific metabolic function, who were <60 and >70 years of age were included. We enrolled thirty-one patients <60 years old and 28 patients >70 years old. General patient characteristics were comparable and liver function did not differ between the two groups. We found no link between old age and diminished liver function that might cause worse outcome in the elderly.\n\nPart IV OUTCOME AFTER LIVER RESECTION: BODY COMPOSITION\n\nIn Chapter 9 we discuss the potential relationship between sarcopenia (low muscle mass) and preoperative non-tumour total liver volume. For this study 40 patients were included and 27 of them were considered sarcopenic based on muscle area measurements performed at the level of the third lumbar vertebra on preoperative contrast enhanced CT scans. The preoperative non-tumour total liver volume of these sarcopenic patients was significantly smaller than in patients without sarcopenia (1396 vs. 1840 mLs). Also, when corrected for body weight, the ratio was still significantly lower in the sarcopenia group. This finding suggests that the preoperative hepatic physiologic reserve may be smaller in sarcopenic patients.\n\nIn Chapter 10 the influence of sarcopenia, obesity and sarcopenic-obesity on liver volume and function was studied. Between 2011 and 2012 all patients (n=80) undergoing a LiMAx liver function test prior to liver surgery were included. Based on CT scans liver volumes were measured and muscle mass and body fat percentage were calculated. Liver function and volume were comparable between patients with and without sarcopenia or sarcopenic-obesity. Obese patients had larger and less functioning livers compared to patients without obesity probably due to deposition of fat. Also, body fat percentage turned out to be an independent prognostic factor for reduced liver function. The amount of liver that can be resected safely might therefore be overestimated in obese patients increasing the risk for postresectional liver failure.\n\nChapter 11 focuses on patients with colorectal liver metastases and the predictive value of sarcopenia, obesity and sarcopenic-obesity on outcome. Again body composition was based on CT measurements and body weight. A total of 171 patients with colorectal liver metastases were included between 2005 and 2012. Having sarcopenia, obesity and sarcopenic-obesity did not affect major complication rates but readmission rates were higher in the obese and sarcopenic obese patients. Disease-free survival and overall survival were not decreased in sarcopenic, obese and sarcopenic obese patients. Obese patients even showed significantly better overall survival and obesity was found to be an independent predictor for better overall survival.\n\nChapter 12 provides a general discussion in which the results are put into context, and conclusions and recommendations are provided.\n\nValorisation addendum\n\nINTRODUCTION\n\nThe liver has the unique capability to regenerate when a portion is removed. For this reason liver resections can most often be performed without permanent loss of liver function. The surgical possibilities to treat primary or secondary malignancies of the liver have been and still are evolving. In time, more and more patients became eligible for potentially curative liver resection. Moreover, larger liver resections are carried out. With this development the complication rate associated with the surgical intervention increased. One of the most feared and often lethal complications after liver surgery is liver failure. Depending on the quality of the liver up to 75% of the liver tissue can be removed. Hereafter it most often will regenerate to almost its full preoperative size. In patients with severe fatty liver disease or cirrhosis a larger remnant needs to be preserved. To prevent liver failure after resection, volumetric analysis of the liver and prediction of the remnant liver volume has found its way into the preoperative assessment in patients with large resections. This improvement in the preoperative assessment unfortunately did not result in the prevention of liver failure in all patients. As it is difficult to predict how much liver tissue can be removed for each individual patient, still up to 9% of patients develop postresectional liver failure.\n\nSOCIO-ECONOMIC RELEVANCE\n\nThe contribution of this thesis in increasing the safety of liver surgery mainly lies in the","auteur":"Toine Lodewick","auteur_slug":"toine-lodewick","publicatiedatum":"15 december 2017","taal":"EN","url_flipbook":"https:\/\/ebook.proefschriftmaken.nl\/ebook\/toinelodewick?iframe=true","url_download_pdf":"","url_epub":"","ordernummer":"FTP-202604130903","isbn":"978-94-6295-778-7","doi_nummer":"","naam_universiteit":"Universiteit Maastricht","afbeeldingen":12196,"naam_student:":"","binnenwerk":"","universiteit":"Universiteit Maastricht","cover":"","afwerking":"","cover_afwerking":"","design":""},"_links":{"self":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio\/11288","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio"}],"about":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/types\/us_portfolio"}],"author":[{"embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/comments?post=11288"}],"version-history":[{"count":1,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio\/11288\/revisions"}],"predecessor-version":[{"id":11289,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio\/11288\/revisions\/11289"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/media\/12196"}],"wp:attachment":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/media?parent=11288"}],"wp:term":[{"taxonomy":"us_portfolio_category","embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio_category?post=11288"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}