The global obesity epidemic has dramatically increased the prevalence of NAFLD and made it the leading cause of chronic liver disease in Western nations. NAFLD is considered the hepatic manifestation of the metabolic syndrome and shares a strong association with type 2 diabetes mellitus, obstructive sleep apnea (OSA), and cardiovascular disease. Although cardiovascular disease is the leading cause of death in patients with NAFLD, the subset of patients who meet histopathologic criteria for NASH are those at greatest risk of liver-related morbidity and mortality. Ludwig and colleagues coined the term NASH in 1980 to describe a cohort of middle-aged patients with elevated serum liver enzyme levels who had evidence of alcohol-associated hepatitis on biopsy specimens in the absence of alcohol consumption. Subsequent study led to the proposed “2-hit” hypothesis in which a sequential progression from isolated fatty liver (IFL) to NASH involved the initial “hit” of hepatic steatosis followed by a second “hit” of oxidative stress resulting in liver injury. It was subsequently recognized that patients who have steatohepatitis on a liver biopsy specimen are at greatest risk for progression to cirrhosis compared with those who have IFL. Correspondingly, our understanding of the pathogenesis of NAFLD has evolved from the 2-hit hypothesis. NASH is expected to become the most common cause of cirrhosis and the leading indication for LT in the USA in the 2020s. As a major public health concern, an understanding of its epidemiology and pathogenesis is paramount to facilitate our ability to effectively diagnose and treat patients with NAFLD and NASH.
NAFLD is an increasingly frequent cause of cirrhosis and HCC. In fact, a report published in 2018 listed NAFLD as the second leading non-neoplastic indication for LT in adults in the USA, following alcohol-associated liver disease. Obesity (BMI ≥30 kg/m2) and type 2 diabetes mellitus are commonly encountered in patients with NAFLD; these 2 diseases have been recognized as risk factors for HCC, irrespective of the presence or etiology of cirrhosis. Although BMI is not necessarily a reliable indicator of adiposity in patients with end-stage liver disease, particularly in those with fluid retention and ascites, it is commonly used by many LT centers during the patient selection process. Morbid obesity (BMI ≥40 kg/m2 without significant obesity-related comorbidities or BMI ≥35 kg/m2 associated with obesity-related comorbidities) is commonly regarded as a relative contraindication to LT; however, data from the Organ Procurement and Transplantation Network demonstrate that 16.5% and 5% of patients who underwent LT in 2016 had a BMI greater than or equal to 35 kg/m2 and greater than or equal to 40 kg/m2, respectively.
NAFLD and Liver Transplantation
Analysis of data from the UNOS registry has suggested that the risk of primary graft nonfunction is increased and short- and long-term survival is poorer in morbidly obese liver transplant recipients with various causes of end-stage liver disease. However, when analyzed as an entire cohort and not stratified by BMI, patients with NAFLD have patient and graft survival rates that are comparable to those for other indications for LT. Many of the key precipitants of NAFLD (obesity, hyperlipidemia, and insulin resistance) are exacerbated by immunosuppression. Recurrence of NAFLD after LT causes graft injury, although graft loss does not typically occur. De novo NAFLD after LT has also been described. In the absence of specific therapy for NAFLD, therapeutic efforts after LT should center on weight control, optimal diabetic management, and use of a lipid-lowering agent, if indicated. Intensive noninvasive weight loss interventions pre-LT appear to be successful (reduction of BMI to <35 kg/m2) in a large proportion of patients (84%) enrolled in carefully monitored multidisciplinary protocols; however, 60% of patients regained weight to a BMI ≥35 kg/m2 post-LT. Although bariatric surgery is feasible in selected patients with NAFLD, this intervention is typically reserved for patients with early stages of liver disease and, as is the case for many other abdominal surgical procedures, is contraindicated in those with decompensated cirrhosis because of high morbidity and mortality. A strategy of combining LT with sleeve gastrectomy during the same operation has only been evaluated in small prospective series. The mean surgical time was not significantly different between LT and combined LT/sleeve gastrectomy, and the mean BMI reduction with the combined surgical approach was 20 kg/m2. Metabolic complications, such as post-transplant diabetes mellitus, as well as steatosis of the graft noted by US were significantly less frequent in patients undergoing LT/sleeve gastrectomy compared with patients who lost weight noninvasively pre-LT. The safety and efficacy of this combined surgical approach and other combinations of less invasive weight loss interventions, such as endoscopic techniques, pre-LT must be confirmed by large prospective studies before they can be recommended. Bariatric interventions are still an option post-LT; however, the procedure should be performed by an experienced surgeon, and the role of less invasive endoscopic techniques postLT is still under investigation.
Sleeve Gastrectomy vs NAFLD
Bariatric surgery leads to substantial weight loss that results in improved metabolic parameters and hepatic histology in patients with NAFLD, according to numerous large retrospective and prospective cohort studies. In one study of 109 patients with NASH who underwent follow-up liver biopsy one year after bariatric surgery, 85% of patients had resolution of NASH, and 33% had improvement in fibrosis. Initial concerns that fibrosis would worsen with rapid weight loss were unfounded, as demonstrated in a meta-analysis in which fibrosis improved by 11.9% from baseline after bariatric surgery. Although bariatric surgery is not recommended as a treatment for NASH, the abundant positive data in its favor suggest that surgical weight loss is a viable option for patients with comorbid conditions that would warrant the surgery for other reasons. Patients with NASH cirrhosis are at potentially higher risk for surgical complications, although some centers have demonstrated encouraging results with sleeve gastrectomy in patients with Child-Pugh class A cirrhosis.
This e-book was designed to assist in learning related to experimental surgical technique, during the training of health professionals. Concisely and objectively, it presents the basic principles for professional practice in surgery and in basic techniques of the most relevant surgical procedures. It is directed to the training of general practitioners, through the technical base, illustrated in procedures described step by step, with reference to the routines of the discipline of Surgical Technique, at the Federal University of Maranhão. It is not a work aimed at surgical clinic nor does it presuppose a descriptive detail that definitively supplies the necessary information for the execution of procedures in patients. This book is specially dedicated to undergraduate students, to serve as a guide during the Experimental Surgical Technique. It was designed and structured in order to facilitate theoretical study and encourage practical learning. Assisting your training, we seek professionals better prepared for health care.
Laparoscopic hepatic resection is an emerging option in the field of hepatic surgery. With almost 3000 laparoscopic hepatic resections reported in the literature for benign and malignant tumors, with a combined mortality of 0.3% and morbidity of 10.5%, there will be an increasing demand for minimally invasive liver surgery. Multiple series have been published on laparoscopic liver resections; however, no randomized controlled trial has been reported that compares laparoscopic with open liver resection. Large series, meta-analyses, and reviews have thus far attested to the feasibility and safety of minimally invasive hepatic surgery for benign and malignant lesions.
The conversion rate from a laparoscopic approach to an open procedure was 4.1%. The most common type of laparoscopic liver resection performed is a wedge resection or segmentectomy (45%), followed by left lateral sectionectomy (20%). Major anatomic hepatectomies are still less frequently performed: right hepatectomy (9%) and left hepatectomy (7%). Cumulative morbidity and mortality was 10.5% and 0.3%.
BENEFITS OF LAPAROSCOPIC APPROACH
More importantly, almost all the studies comparing laparoscopic with open liver resection consistently showed a significant earlier discharge to home after laparoscopic liver resection. Lengths of stay were variable based on the country of origin of the studies but were consistently shorter for laparoscopic liver resection. Three studies published in the United States presented a length of stay of 1.9 to 4.0 days after laparoscopic liver resection. Studies from Europe showed an average length of stay of 3.5 to 10 days whereas those from Asia reported an average of length of stay of 4 to 20 days after laparoscopic liver resection.
Vanounou and colleagues used deviation-based cost modeling to compare the costs of laparoscopic with open left lateral sectionectomy at the University of Pittsburgh Medical Center. They compared 29 laparoscopic with 40 open cases and showed that patients who underwent the laparoscopic approach faired more favorably with a shorter length of stay (3 vs 5 days, P<.0001), significantly less postoperative morbidity (P 5 .001), and a weighted-average median cost savings of $1527 to $2939 per patient compared with patients who underwent open left lateral sectionectomy.
Initial concerns about the adequacy of surgical margins and possible tumor seeding prevented the widespread adoption of laparoscopic resection approaches for liver cancers. In comparison studies, there were no differences in margin-free resections between laparoscopic and open liver resection. In addition, no incidence of port-site recurrence or tumor seeding has been reported. With more than 3000 cases of minimally invasive hepatic resection reported in the literature (and no documentation of any significant port-site or peritoneal seeding), the authors conclude that this concern should not prevent surgeons from accepting a laparoscopic approach.
There were no significant differences in overall survival in the 13 studies that compared laparoscopic liver resection with open liver resection for cancer. For example, Cai and colleagues showed that the 1-, 3-, and 5-year survival rates after laparoscopic resection of HCC were 95.4%, 67.5%, and 56.2% versus 100%, 73.8%, and 53.8% for open resection. For resection of colorectal cancer liver metastasis, Ito and colleagues showed a 3-year survival of 72% after laparoscopic liver resection and 56% after open liver resection whereas Castaing and colleagues51 showed a 5-year survival of 64% after laparoscopic liver resection versus 56% after open liver resection.
Compared with open liver resections, laparoscopic liver resections are associated with less blood loss, less pain medication requirement, and shorter length of hospital stay. A randomized controlled clinical trial is the best method to compare laparoscopic with open liver resection; however, such a trial may be difficult to conduct because patients are unlikely to subject themselves to an open procedure when a minimally invasive approach has been shown feasible and safe in experienced hands. In addition, many patients would have to be accrued to detect a difference in complications that occur infrequently. Short of a large randomized clinical trial, meta-analysis and matched comparisons provide the next best option to compare laparoscopic with open liver resection. For laparoscopic resection of HCC or colorectal cancer metastases, there has been no difference in 5-year overall survival compared with open hepatic resection. In addition, from a financial standpoint, the minimally invasive approach to liver resection may be associated with higher operating room costs; however, the total hospital costs were offset or improved due to the associated shorter length of hospital stay with the minimally invasive approach.
“At the University of Chicago, members of the Department of Surgery decided to investigate this issue more precisely. As stay-at-home restrictions in some states are easing, and as non-emergency medical care is being reconsidered, how does one possibly triage the thousands upon thousands of patients whose surgeries were postponed? Instead of the term “elective,” the University of Chicago’s Department of Surgery chose the phrase “Medically-Necessary, Time Sensitive” (MeNTS). This concept can be utilized to better assess the acuity and safety when determining which patients can get to the operating room in as high benefit/low risk manner as possible. And unlike in any recent time in history, risks to healthcare staff as well as risks to the patient from healthcare staff, are now thrown into the equation. The work was published in the April issue of the Journal of the American College of Surgeons.
On March 17, 2020, the American College of Surgeons recommended that all “elective” surgeries be canceled indefinitely. These guidelines were published, stating that only patients with “high acuity” surgical issues, which would include aggressive cancers and severely symptomatic disease, should proceed. Based on the Elective Surgery Acuity Scale (ESAS), most hospitals were strongly encouraged to cancel any surgery that was not high acuity, including slow-growing cancers, orthopedic and spine surgeries, airway surgeries, and any other surgeries for non-cancerous tumors. Heart surgeries for stable cardiac issues were also put on hold. Patients and surgeons waited. Some patients did, indeed undergo non-Covid-19-related surgeries. But most did not. Redeployment is gradually turning to re-entry.
The re-entry process for non-urgent (yet necessary) surgeries is a complicated one. Decisions and timing, based on a given hospital’s number and severity of Covid-19 patients, combined with a given city or state’s current and projected number of Covid-19 cases, how sick those patients will be, and whether or not a second surge may come, involves a fair amount of guesswork. As we have all seen, data manipulation has become a daily sparring match in many arenas. The authors of the study created an objective surgical risk scoring system, in order to help hospitals across this country, as well as others across the world, better identify appropriate timing regarding which surgeries can go ahead sooner rather than later, and why. They factored several variables into their equation, to account for the multiple potential barriers to care, including health and safety of hospital personnel. They created scoring systems based on three factors: Procedure, Disease and Patient Issues.
The authors of the study created an objective surgical risk scoring system, in order to help hospitals across this country, as well as others across the world, better identify appropriate timing regarding which surgeries can go ahead sooner rather than later, and why. They factored several variables into their equation, to account for the multiple potential barriers to care, including health and safety of hospital personnel. Each patient would receive an overall conglomerate score, based on all of these factors, with the lower risks giving them more favorable scores to proceed with surgery soon, and the higher risks giving patients a higher score, or higher risk regarding proceeding with surgery, meaning it may be safest, for now, to wait.
Dr. Jeffrey Matthews, senior author of the paper, and Department Chair at the University of Chicago, stated that this model is reproducible across hospital systems, in urban, rural, and academic settings. And in the event of potential unpredictable surges of Covid-19 cases, the scoring system “helps prioritize cases not only from the procedure/disease standpoint but also from the pandemic standpoint with respect to available hospital resources such as PPE, blood, ICU beds, and [regular hospital] beds.”
The scoring system is extremely new, and the coming weeks will reveal how patients, surgeons and hospitals are faring as patients without life-and-death emergencies and/or Covid-19 complications gradually begin filling the operating rooms and hospital beds. In addition, and perhaps just as important, the study authors note that creating systems whereby healthcare resources, safety, and impact on outcomes need to be considered more carefully for each patient intervention, the larger impact of each intervention on public health will be better understood: not only for today’s pandemic, but also in future, as yet unknown, global events.”
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The current world Covid-19 pandemic has been the most discussed topic in the media and scientific journals. Fear, uncertainty, and lack of knowledge about the disease may be the significant factors that justify such reality. It has been known that the disease presents with a rapidly spreading, it is significantly more severe among the elderly, and it has a substantial global socioeconomic impact. Besides the challenges associated with the unknown, there are other factors, such as the deluge of information. In this regard, the high number of scientific publications, encompassing in vitro, case studies, observational and randomized clinical studies, and even systematic reviews add up to the uncertainty. Such a situation is even worse when considering that most healthcare professionals lack adequate knowledge to critically appraise the scientific method, something that has been previously addressed by some authors. Therefore, it is of utmost importance that expert societies supported by data provided by the World Health Organization and the National Health Department take the lead in spreading trustworthy and reliable information.
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The operative conduct of the biliary-enteric anastomosis centers around three technical steps: 1) identification of healthy bile duct mucosa proximal to the site of obstruction; 2) preparation of a segment of alimentary tract, most often a Roux-en-Y jejunal limb; and 3) construction of a direct mucosa-to-mucosa anastomosis between these two. Selection of the proper anastomosis is dictated by the indication for biliary decompression and the anatomic location of the biliary obstruction. A right subcostal incision with or without an upper midline extension or left subcostal extension provides adequate exposure for construction of the biliary-enteric anastomosis. Use of retractors capable of upward elevation and cephalad retraction of the costal edges are quite valuable for optimizing visual exposure of the relevant hilar anatomy.
Division of the ligamentum teres and mobilization of the falciform ligament off the anterior surface of the liver also facilitate operative exposure; anterocephalad retraction of the ligamentum teres and division of the bridge of tissue overlying the umbilical fissure are critical for optimal visualization of the vascular inflow and biliary drainage of segments II, III, and IV. Cholecystectomy also exposes the cystic plate, which runs in continuity with the hilar plate. Lowering of the hilar plate permits exposure of the left hepatic duct as it courses along the base of segment IVb. In cases of unilateral hepatic atrophy as a result of long-standing biliary obstruction or preoperative portal vein embolization, it is critical to understand that the normal anatomic relationships of the portal structures are altered. In the more common circumstance of right-sided atrophy, the portal and hilar structures are rotated posteriorly and to the right; as a result, the portal vein, which is typically most posterior, is often encountered first; meticulous dissection is necessary to identify the common bile duct and hepatic duct deep within the porta hepatis.