Bariatric Surgery is a treatment option if ALL of the following criteria are fulfilled:
BMI ≥ 40, or 35 ≤ BMI <40 with significant disease that could be improved by weight loss.
Failure to achieve or maintain adequate and clinically beneficial weight loss despite all appropriate non-surgical measures for at least 6 months.
The patient has been receiving or will receive intensive management in a specialist obesity service.
The patient is generally fit for anaesthesia and surgery.
The patient commits to long-term follow up.
Roux-En-Y Gastric Bypass
Roux-en-Y gastric bypass (RYGB) is the most commonly performed bariatric operation in the UK and USA. The Roux-en-Y type of gastrointestinal anastomosis was first introduced in the nineteenth century by the Swiss surgeon, César Roux. Roux was the first Professor of External Pathology and Gynaecology at the University of Lausanne and was well recognised throughout Europe as a surgical innovator and educator. He published several articles on gastroenterostomy, which was mostly performed for gastric outlet obstruction at that time. The Y connection was documented in the publication in 1897 but was subsequently abandoned by surgeons due to the high rate of marginal ulcers and mortality . In 1950, Dr Edward Mason and colleagues at the University of Iowa Hospitals and Clinics modified the Roux procedure into the current anti-obesity gastric bypass based on the weight loss observed among patients undergoing partial stomach removal for ulcers [13, 14]. In 1994, Dr. Alan Wittgrove reported the first five cases of laparoscopic approach . This was achieved through 5 to 6 small abdominal incisions with an induced pneumoperitoneum. Studies comparing clinical outcomes of open and laparoscopic procedures have shown that laparoscopic gastric bypass is associated with lower overall postoperative complications and mortality, shorter length of stay, and lower hospital costs [16, 17].
The procedure consists of (1) creating a small gastric pouch of no more than 5–6 cm that is separated from the fundus. MacLean et al. described the formation of vertical gastric pouch, where a pouch on the lesser curvature was made adjacent to a 28 or 30 Fr bougie using a stapler that made two double rows of staples with an interval of free tissue in between to permit division. The staple line on the pouch side was oversewn and the gastric side was inverted [18, 19]. (2) Reconstructing the GI tract in which the jejunum, usually between 15 and 50 cm from the ligament of Treitz, is divided and rearranged into a Y- configuration. The “Roux limb” is the section from the gastrojejunostomy to jejunojejunostomy anastomosis, which enables the outflow of the food from the gastric pouch into the jejunum, bypassing the duodenum (Fig. 7.1). The gastrojejunostomy can be created by linear stapling, circular stapling or hand-sewn techniques . When applying the circular stapling technique, the anvil of the stapler can be inserted transorally or transabdominally [21, 22]. The biliary limb is anastomosed to the alimentary limb to form the common channel where food mixes with the digestive enzymes. Lengthening of the Roux limb and biliary limb leads to shortening of the common limb. The biliary limb is commonly kept short in the existing literature, leaving the length of the Roux limb open to debate. Studies in the early 1990s demonstrated an increase in excess body weight loss in patients with extended Roux limb of around 100–150 cm, compared to 40–75 cm [23, 24]. Roux limb length equal or greater than 150 cm is performed in superobese patients (BMI > 50 kg/m2) with limited evidence [23–27]. Metabolic complications and nutritional deficiency are likely to occur in patients with short common channels .
Studies have shown reduced hunger, increased satiety and altered bile salt concentrations in patients with RYGB, which are associated with exaggerated responses of anorexigenic intestinal hormones such as glucagon-like polypeptide-1 (GLP-1) and peptide YY (PYY); [26, 27] these changes in gut hormones are absent in gastric band surgery . Changes in taste include food preferences with high-calorie foods becoming less appealing and less consumed. This was demonstrated using functional magnetic resonance imaging (MRI), which showed that activation of brain reward systems during evaluation of the appeal of high-calorie food was less after gastric bypass than gastric banding . Energy expenditure also increases after surgery and research into mechanisms is ongoing.
Early post-operative complications include anastomotic leak, gastrointestinal bleed from the staple line, deep vein thrombosis, pulmonary embolism, and respiratory failures. Late complications include bowel obstruction, internal hernia, stomal stenosis, marginal ulcer, and vitamin/micronutrient deficiencies.
Belachew et al. first described the technique for laparoscopic adjustable gastric band (LAGB) in 1995 . Since then, modified techniques and different types of gastric bands have been developed. The perigastric pathway was the traditional approach for tunnelling the band posteriorly. However, there was a tendency for the posterior wall of the stomach to prolapse through the band and therefore has been replaced by the pars flaccida approach . A retrospective multicentre study compared the two approaches with more than 1200 patients in each treatment group. This showed a significantly higher rate of gastric pouch dilatation, intragastric migration and conversion to laparotomy in the perigastric group .
Five or six trocars are used, including one for the liver retractor. The dissection begins at the lesser curvature where an opening is made. Dissection continues through the retrogastric tunnel towards the angle of His. The band is introduced through a large trocar and placed at the top of the stomach, above the lesser sac, including the fat and vagus nerve branch within the band  (Fig. 7.2). The majority of surgeons achieve anterior fixation of the band by creating a gastro-gastric tunnel with interrupted sutures to reduce the risk of anterior slippage, however, the consequences on band erosion remain unknown. The access port for adjustment of band tightness is placed on the anterior rectus sheath and should be easily accessible for percutaneous needle puncture.
The primary mechanism of action of gastric banding is inducing a background of satiety and early post-prandial satiation. The feeling of satiety is likely to be mediated by the vagal receptors in the apex of the gastric cardia, and therefore the correct band placement is crucial to achieve the desired effect. Band adjustment is made with a non-coring deflected needle (Huber point needle). Follow up should be offered to patients every 4–6 weeks with the aim of achieving optimal restriction for individual patients. The Centre for Obesity Research and Education (CORE), Monash Medical School, Melbourne, Australia describes the optimal restriction as the “Green Zone” (Table 7.2), which is achieved by successive incremental adjustments and close monitoring of weight loss and symptoms. Patient follow-up plays an important role in the amount of excess weight loss (EWL); Shen et al. showed that patients who had more than six times of follow up within 1 year achieved 50 % EWL compared to the 42 % for those who had 6 or less follow up times (P = 0005) .
The Centre of Obesity Research and Education (CORE), Monash Medical School, Melbourne, Australia describes the “Green Zone” as the optimal adjustment for gastric band
Looking for food
LAGB has a low perioperative complication rate compared to RYGB. Late complications include band prolapse (slippage), band erosion, and access port infection. The clinical presentation of band prolapse can be non-specific and therefore difficult to diagnose. Symptoms include acid reflux, heartburn, coughing, choking spells and wheezing. Prolapse of the posterior wall of the stomach is managed by removal of the band and replacement of a new band via the pars flaccida pathway, whereas prolapse of the anterior wall can be managed by mobilisation and reduction of prolapse if the stomach is not overly oedematous .
The first open sleeve gastrectomy was performed by Dr Doug Hess, Bowling Green, Ohio in 1998 as a part of the biliopancreatic diversion and duodenal switch procedure (BPD-DS) . In 2000, Michel Gagner first described laparoscopic sleeve gastrectomy (LSG) as the first step of BPD-DS, which is now widely adopted [37, 38]. The greater omentum is divided with ultrasonic shears along the greater curvature up to the fundus and down to 2 cm proximal to pylorus. The angle of His is then dissected free from the left crus of the diaphragm. A 28–54 Fr bougie is inserted along the line of the lesser curvature to guide the dissection of creating a thin tube. The size of the gastric pouch is dependent on whether LSG was performed independently or as a part of BPD-DS . The stomach is divided from the incisura angularis to the angle of His with the sequential use of linear stapling devices (Fig. 7.3).
Sleeve gastrectomy is now considered as an effective stand-alone procedure for high risk super-obese patients and is associated with improvement in comorbidities and a low complication rate [40, 41]. The mechanism of action is unclear, but it is thought to be mainly restrictive with some neurohumoral changes.
Complications of sleeve gastrectomy include staple-line bleeding, leak, and late stricture. Gastroesophageal reflux symptoms are common in the long term. A perceived benefit of the sleeve is that if there is weight regain afterwards, it is still possible to convert to another bariatric operation such as gastric bypass or duodenal switch.
Bilio-Pancreatic Diversion with Duodenal Switch
Professor Nicola Scopinaro first introduced the bilio-pancreatic diversion (BPD) in 1979 . It was designed as a safer technique to the jejunoileal bypass performed from the 1950s to 1970s. It had significant nutritional and metabolic complications and therefore was modified to include a duodenal switch (DS) in an attempt to eliminate them . BPD-DS is technically challenging and usually considered as a planned second stage or rescue operation (duodenoileostomy/ileo-ileostomy) after a sleeve gastrectomy. The gastrocolic ligament is divided from the distal antrum to proximal duodenum. The dissection of the duodenum ends at the point where the anterior pancreatic tissue joins the duodenal wall. A linear stapler is used to transect the duodenum. The common limb is measured 50–100 cm from the ileocaecal valve and the alimentary limb is therefore variable in length (about 200–300 cm). The ileum is divided at the point of measurement and the duodeno-ileostomy is performed as an end-to-end anastomosis with a circular stapler. The bilio-pancreatic limb is joined to the common limb by a side-to-side ileo-lieostomy.
The BPD-DS is a combination procedure that is both restrictive and malabsorptive. It produces effective weight loss in patients with a BMI > 50 and may be superior to RYGB in achieving weight loss . Dorman and colleagues compared 190 patients who underwent primary BPD-DS between 2005 and 2010 to 139 RYGB patients. They found no difference between percent total weight loss between the two groups and significantly higher improvements in type 2 diabetes, hypertension and hyperlipidaemia in the BPD-DS group .
Patients having BPD-DS require rigorous life long medical and nutritional follow up as long-term nutritional and vitamin deficiencies occur at a significant rate .
Surgical Training in Bariatric Surgery
In the USA, the number of bariatric cases has grown from approximately 40,000 in 2000, to 80,000 in 2002 and to a current estimate of 113,000 cases per year [44, 45]. In the UK, there had been a 30-fold increase in the last decade to more than 8000 cases in 2011 . Bariatric surgery is now possibly the commonest gastrointestinal operation in the USA and this has led to a significant increase in the number of bariatric programmes. A risk of this is that many surgeons might enter into bariatric practice without sufficient training and experience, or work in institutions without sufficient infrastructure to provide the necessary multidisciplinary structure for the overall care .
The current professional standards to accredit bariatric surgeons and institutes in the UK and USA are based on case volume, hospital infrastructure and staffing requirements for the multidisciplinary team [48, 49]. These requirements are established upon the strong evidence of improved patient outcomes under the care of high volume surgeons and high volume centres and the assumption that volume of cases directly reflects a surgeon’s competency . A bariatric training programme needs to meet the increasing clinical demand whilst maintaining patient safety.
Challenges in Bariatric Training
Two thirds of oesophago-gastric Upper Gastro-Intestinal trainees in the UK have shown a commitment towards training in Bariatric surgery (Fig. 7.4). However, trainees are not expected to attain full competence in advanced sub-speciality procedures by the time of their Certificate of Completion of Training (CCT) according to the Intercollegiate Surgical Curriculum Project (ISCP) surgical curriculum. The majority of trainees therefore feel unable to practise as a specialist at the end of their general surgical training (Fig. 7.5) . As a result, almost 100 % of bariatric trainees wish to undertake a fellowship programme. A possible explanation is the apparent number of low volume bariatric units, suggesting less exposure to bariatric operations. Data from the UK suggests that only 20 bariatric surgeons operated on more than 100 procedures a year and only 11 hospitals carried out >200 procedures a year from 2008 to 2010 .
Two thirds of OG trainees were interested in Bariatric surgery
The majority of trainees feel unable to practice as a specialist at the end of CCT
The understanding of proficiency-gain curve forms the foundation of training development. A proficiency-gain curve is defined as the number of procedures that a surgeon needs to perform to reach a plateau in operating time, conversion rates, complications and mortality. Laparoscopic Roux-en-Y gastric bypass (LRYGB) is the most commonly performed operation and has received the most attention.
In 2002, Dr Oliak and colleagues analysed the first 225 consecutive LRYGB operations performed by one laparoscopic surgeon and showed that most of the reduction in operative time occurred over the first 75 patients . The perioperative complication rate also decreased from 32 % for the first 75 patients to 15 % for the second 75 patients. A study done by Pournaras et al. in the UK similarly demonstrated a proficiency-gain curve of 100 in which the mean operative time decreased significantly after the first 100 patients . Studies have shown that the early part of the proficiency-gain curve is associated with higher mortality and morbidity. A historical paper published by Flum & Dellinger in 2004 evaluated 30-day mortality of 3,328 patients who underwent obesity procedures over a 15-year study period. When the mortality was considered in a multivariable logistic regression analysis, only surgical inexperience and patients’ comorbidities were associated with increased 30-day mortality . The odds ratio of patient death within 30 days of hospital discharge was 4.7 times higher within the surgeon’s first 19 procedures. One of the main objectives of bariatric surgery is to reduce mortality, and therefore the mortality of patients undergoing surgery should not be higher than patients without surgery. Adams et al. reported 7,925 RYGB performed by six surgeons between 1984 and 2002 in Salt Lake City, Utah; patients were matched for age, sex, and BMI . There was no difference in mortality between the operated (42 deaths) and non-operated (41 deaths) patients in the first year with a mortality of 0.52 % . This implies that surgeons who perform elective RYGB should have an operative mortality of 0.5 % or less in the first year. The first UK National Bariatric Surgery Registry report to March 2010 showed a mortality rate of only 0.2 % for RYGB; complication rates varied from 1 to 22 % depending on the series. Any new surgeon must keep their outcomes within these parameters to avoid the proficiency-gain curve effect. Establishing evidence-based training methods is crucial in reducing the proficiency-gain curve, ensuring patient safety, minimising differences in complication rate and mortality during the proficiency-gain curve.
Educational Tools for Training and Education/Assessment
Courses and workshops have become increasingly common in the last 10 years to improve patient safety while surgeons are on the proficiency-gain curve. Options of obtaining training in LRYGB include 1–2 day courses, extended mentoring by an experienced surgeon, “mini-fellowships” which range from 1 to 6 weeks in duration, and 6–12 months fellowship . The LRYGB can be broken down into its constituent parts, allowing task-based learning until each step is mastered. If trainees understand the steps of the procedure and become competent at individual tasks such as laparoscopic suturing then they start at a higher point on the proficiency-gain curve. Simulation and live animal models are commonly used in short courses; the animals are anaesthetised and provide in vivo conditions. This helps trainees master the procedure in a risk free environment and provides a good bridge to optimise time later spent with human cadavers. The bariatric training courses culminate in the cadaver course, which uses education theory on how we learn to optimise education outcomes. A relationship between the bariatric course and the experiential learning model can be seen in Fig. 7.6 . Course participants move around the learning cycle starting with expert demonstrations and discussion of the surgery. This is followed by cadaveric dissection, reflection (self-assessed or formal by trainers) with “tips and tricks” to improve their performance and mentoring by expert faculty to modify surgical practice. Trainees then start around the cycle again with further surgery under guidance from the faculty. This optimises instruction in advanced laparoscopic techniques from the start of the operation. Details such as the operating theatre set-up, patient positioning, trocar placement and the efficient use of instrumentation are included. Non-technical skills such as teamwork leadership, safety and communication are also part of the operative training.
The bariatric training pathway cumulates in a fellowship of 6 months to 1 year depending on previous experience. Laparoscopic bariatric surgery requires mastery of a broad range of cognitive and technical skills. The curriculum of Bariatric and Metabolic Fellowship in the UK clearly states the requirement of fellows (Table 7.3) . Fellowships are usually undertaken post-CCT or within the last 12 months of specialist training. Fellows are expected to achieve a minimum number of 100 weight loss operations of which >51 % are as the primary operating surgeon. A validated logbook including workplace based assessments (Table 7.4), in particular, procedure-based assessments (PBAs) are used as reflective templates in order to further reduce patient morbidity and mortality related to the proficiency-gain curve. The fellowship allows trainees to finish the proficiency-gain curve with a mentor and achieve competency as a bariatric specialist, including the opportunity to manage short and intermediate-term complications and be a part of the multidisciplinary bariatric team.
Bariatric and Metabolic Fellowship Core Curriculum for the RCS National Surgical Fellowship Scheme 
Epidemiology of obesity
Pathophysiology of morbid obesity and the metabolic syndrome
Therapeutic options for morbid obesity
Indications for weight loss and metabolic surgery
The principles of perioperative management of the obese patient
Types of operations performed and mechanisms of action
Complications of metabolic surgery and their management
Revisional metabolic surgery
Long term management of the bariatric patient following surgery
Essential components of a bariatric service
Psychology of the morbidly obese patient
History and examination of the obese patient
Interpretation of investigations in the obese patient
Preoperative evaluation and optimisation
Assessment of the post-operative bariatric patient
Management decisions for early and late complications of bariatric surgery
Laparoscopic access in the morbidly obese
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