Roux-en-Y Gastric bypass is a restrictive-malabsorptive procedure introduced in 1966 by Mason. It has accounted for over 60 to 70% of all bariatric operations in the United States since 2003. However, FDA approval in 2001 has led to a slow uptake of banding, which in 2011 exceeded bypass (46% vs. 44%) in estimated figures.[rx] Sleeve gastrectomy is the next most commonly performed operation (7.8%), becoming increasingly popular in modern practice due to its lower risk profile and similar outcomes to bypass.[rx][rx] Developments in laparoscopy across all fields of abdominal surgery have led to laparoscopic bariatric procedures now accepted as the standard of care. The low morbidity and mortality associated with laparoscopic procedures have led to day-case surgery for bypass and gastrectomy procedures, establishing bariatrics as a cost-effective intervention.[rx]
Obesity is defined by WHO according to body mass index – BMI (kg/m^2) 18.5 to 24.9 normal range, 25 to 25.9 overweight (pre-obese), 30 to 34.9 obese class I, 35-35.9 obese class II, 40 to 49.9 obese class III.[rx]
Anatomy and Physiology
The stomach is comprised of the four anatomical regions described below:
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Cardia: The select stomach region was immediately inferior to the gastro-oesophageal junction.
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Fundus: Dome-shaped portion found adjacent and lateral to the cardia.
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Body: Forms the main bulk of the stomach below the cardia and fundus.
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Pylorus: It starts at the angular notch between the body and the pylorus. Comprised of the antrum, canal, and sphincter, this structure appears at the L1 vertebral level. It links the stomach and small bowel.
Lesser and greater curvatures:
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Greater curvature– starts at the cardiac notch; passes in a long curve, forming the lateral border of the fundus, body, and pyloric antrum. Arterial supply is via the short gastric and the gastroepiploic (right and left) arteries.
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Lesser curvature– starts at the gastroesophageal junction and runs along the medial surface of the stomach to the angular notch. The lesser curvature receives its supply from the left gastric artery (celiac trunk) and the right gastric artery (stemming from the hepatic artery).
Anatomical Relations:
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Superior: Superiorly, the stomach is related to the esophagus and left hemidiaphragm
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Anterior: Anterior to the stomach (from superficial to profound) lies the abdominal wall, diaphragm, left lobe of the liver, and greater omentum
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Posterior: Posterior to the stomach is the lesser sac. Retroperitoneal structures include the pancreas, left kidney, and suprarenal gland; intraperitoneal facilities include the spleen and splenic artery.
Peritoneal attachments:
Greater omentum – A double layer of peritoneum originating from the greater curvature of the stomach that traverses the peritoneal cavity. The greater omentum folds around and attaches to the transverse colon. The function of the greater omentum is to adhere to inflamed tissues and prevent the spread of infection across the peritoneal cavity.
Lesser omentum – The role of the lesser omentum is to attach the stomach to the liver. It arises from the lesser curvature of the stomach and travels to the liver.
The two omenta divide the peritoneal cavity into the greater and lesser sacs that communicate via the epiploic foramen of Winslow. The lesser sac lies posterior to the stomach and anterior to the pancreas. The greater sac contains the small and more significant bowel.
Blood supply:
The arterial supply to the stomach is via a rich anastomotic network that arises from the celiac trunk and its branches.
- Right gastric artery – The celiac trunk branches into the common hepatic artery, giving rise to the right gastric artery.
- Left gastric artery – One of three branches of the celiac trunk
- Right gastroepiploic artery – The celiac trunk branches into the common hepatic artery, which then branches into the gastroduodenal artery, which gives rise to the right gastroepiploic street.
- Left gastroepiploic artery – The celiac trunk branches into the splenic artery, giving rise to the left gastroepiploic lane.
Venous Drainage
The veins of the stomach share names with the arteries. The right and left gastric veins to drain directly into the hepatic portal vein, whereas the short gastric and gastroepiploic veins drain into the superior mesenteric vein.
Innervation:
The vagus nerve (10th cranial nerve) supplies the parasympathetic nerve supply to the stomach.
The greater splanchnic nerve arises from the T6-T9 spinal cord segment and supplies sympathetic nerve supply to the stomach.
Indications
The National Institute for Clinical Excellence in the UK released guidelines for offering bariatric surgery. The policies in the US are also on similar lines. The indications must include all of the following:
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BMI >40 kg/m^2 or between 35 and 40 kg/m^2 with weight loss responsive disease
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All nonoperative measures have failed to maintain weight loss for >6 months
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Managed through a specialist obesity service
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Fit enough to survive anesthesia and surgery
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Commits to long term follow up
Assessing commitment to the follow-up process is challenging to evaluate preoperatively. Successful weight loss through medical management is not an established predictor of this.[rx]
Contraindications
Relative contraindications can include Crohn’s disease and psychosocial disorders, including drug or alcohol use disorders. A high degree of patient understanding of surgery’s risks and lifestyle implications needs to be proven; hence, patients with severe intellectual disabilities are unlikely to be successful candidates. Patients with epilepsy should have a review of their medications as the absorption is affected by bypass surgery. Hence, careful decision-making with the involvement of pharmacists and neurologists should be sought preoperatively.[rx]
Absolute contraindications include pregnancy. Those with severe incapacitating systemic diseases, including end-stage renal disease, unstable coronary artery disease, severe heart failure, cirrhosis, portal hypertension, and active cancer, are not offered surgery.[rx]
Equipment
Equipment for a laparoscopic RYGB includes:
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Orogastric tube
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Nathanson liver retractor
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For access: Scalpel with no. 11 blade, Langenbach retractors, artery clips
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A 30-degree laparoscope – with light source and monitor
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Gas insufflation equipment
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Hasson trocars: 5 mm and 10 to 12 mm ports
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Three bowel-safe graspers
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Laparoscopic ultrasonic dissector (e.g., harmonic scalpel)
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Electrocautery equipment
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Laparoscopic suction irrigator
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Laparoscopic clips
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Medium wound protector
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Laparoscopic linear cutting stapler
Personnel
Within an operating theatre, the surgical team consists of a lead operator, assisting surgeon, scrub nurse, and theatre assistants. The anesthetic team consists of anesthesiologists and CRNAs (anesthesiologist’s assistants).
This operation’s workup and interprofessional care include bariatric nurse specialists, endocrinologists, gastroenterologists, dieticians and nutritionists, and ward teams, including doctors, nurses, pharmacists, health care assistants, and administrative staff.
Preparation
The interprofessional team plays a pivotal role in the management of bariatric patients. The team consists of bariatric surgeons, bariatric physicians, specialist anesthetists, bariatric nurse specialists, and psychologists. Many patients are also encouraged to attend support groups.[rx] The team educates the patients on various operations, their implications, reversibility, and complications.[rx]
Another role of the team is to identify treatable comorbidities in the surgical candidate and optimize these. The focus should be on managing obstructive sleep apnoea and type 2 diabetes mellitus.[rx] With medical optimization, anesthetic risk can be reduced, as assessed by the American Society of Anaesthesiology (ASA) grade.
Risk stratification of patients is an area of research aiming to optimize better which patient cohorts receive an offer for bariatric surgery. The Obesity Surgery-Mortality Risk score (OS-MRS), validated for use in gastric bypass, scores patients out of 5 for the male sex, age greater than or equal to 45, BMI greater than or equal to 50, presence of hypertension, known risk of venous thromboembolic disease. Low-risk patients in class A (0-1 points) have a 12-fold decreased mortality risk compared to class C (4-5 points).[rx] Interestingly, data from the UK and Ireland National Bariatric Surgery Registry (NBSR) indicate that bypass operations are performed much more commonly in class C patients.
Patients should start on a two-week milk diet, reducing the liver size, resistance, and constraints on laparoscopic instrument movement.[rx]
On the day of the surgery, the patient receives venous thromboembolism prophylaxis, and TED stockings or intermittent pressure calf compression devices are applied bilaterally.
Technique
Laparoscopic techniques vary between surgeons, and there is no established standardization. The steps of Roux-en-Y-gastric bypass (RYGB) include 1) gastric pouch creation, 2) creation of biliopancreatic limb, 3) jejunojejunostomy creation, and 4) creation of gastrojejunostomy.
Under general anesthesia, the patient positioning is in the supine split leg position. The lead operating surgeon stands between the legs once the patient is prepped and draped, and the monitor is positioned above the patient’s head. Establishing pneumoperitoneum in severely obese patients can be a challenging task. Most commonly, the Veress needle is inserted in the right hypochondrium, and an optical trochar inserted 4 to 5 cm above the umbilicus is used to gain access. The surgeon inserts additional 12 mm ports in the left and right upper quadrants. A 5 mm port and Nathanson retractor secured to Martin’s arm are inserted to retract the liver.
Step 1: Gastric Pouch Creation
Adequate exposure to the gastroesophageal junction is essential, which can be facilitated by placing the patient in reverse Trendelenburg, retracting the left lobe of the liver away using a Nathanson retractor, and retracting the omentum inferiorly.
Dissection begins at the angle of His to expose the left crus of the diaphragm and gastrohepatic ligament. The pars flaccida and retro gastric attachments are divided to mobilize the stomach. The lesser sac is entered along, the lesser curvature separating neurovascular branches from the left gastric artery and vein.
MacLean et al. demonstrated that the optimal gastric pouch is 20 to 30 cc in volume and primarily involves the lesser curve of the stomach. Long-term follow-up has shown steady weight loss over 15 years with this technique.[rx] Linear staplers are initially directed transversely, starting at the inferior border of the oblique fat pad. A 2 to 3 cm bite is taken. The linear stapler is then fired vertically towards the angle of His.
Step 2: Creation of the Biliopancreatic Limb
The biliopancreatic limb, also known as the afferent limb, consists of the duodenum and proximal jejunum that remains in continuity with the remnant stomach proximally. The stem contains digestive enzymes from the stomach, hepatobiliary tract, and pancreas. In a standard gastric bypass, approximately 40 cm is measured starting at the ligament of Treitz and divided using a stapling device to create the biliopancreatic (BP) limb.
Step 3: Creation of Jejunojenuostomy
The roux limb is measured 75 to 150 cm from the jejunal division point for an average of 120 cm. The biliopancreatic limb is anastomosed to the distal segment of the jejunum at this point to create side-to-side jejunojejunostomy – the JJ anastomosis.
Step 4: Creation of Gastrojejunostomy
The Roux limb of the jejunum can be brought up either in an ante colic-antegastric or a retro comic-retro gastric orientation. A side-to-side gastrojejunostomy is then created using a linear stapling device with suture closure of the defect. Suppose the anastomosis is performed in a retro comic pattern. In that case, it is essential to recognize the transverse mesocolon defect (Petersen’s space) that could be a potential site of internal herniation of intestinal loops. Securing the mesenteries of the biliopancreatic, roux limb, and transverse mesocolon thus obliterates this possible hernia site.
Leak test
Before the completion of the procedure, an upper endoscopy leak test is performed while keeping the gastrojejunostomy in view. The gastric pouch and gastrojejunostomy are submerged in saline with the patient in Trendelenburg. An endoscope is advanced across gastrojejunostomy to assess patency and then inflated with air. The submerged anastomosis undergoes inspection for bubbling that would indicate a leak. Some surgeons prefer methylene blue dye instead of air to check for a leak.
Post-procedure care:
Protocols vary regarding post-procedure care and length of stay. An overnight stay is recommended to be safe for most patients, according to one study.[rx] Same-day discharge has been shown to correlate with increased morbidity and mortality, and hence most centers avoid it.[rx]
Complications
The mortality from gastric bypass is roughly 0.2%, higher than sleeve gastrectomy and gastric banding, with the lowest mortality of the three.[rx]
Early Complications:
An anastomotic leak from gastrojejunal anastomosis is a potentially fatal complication. It typically manifests within 24 hours and can occur in as much as 3% of cases.[rx] A leak test performed intraoperatively helps to mitigate the chances of a leak. Same-day laparoscopy and repair or T tube placement may be indicated. Healing is generally impaired in these patients due to their comorbidities and the inevitable catabolic state with this surgery.
Hemorrhage from anastomoses and staple lines has a high chance of resolving spontaneously – but may require transfusion while awaiting resolution.[rx]
Bowel obstruction can occur early or late, the former due to Roux-en-O error, where the closed-loop obstacle is created by misidentification of Roux and BP limbs. Early bowel obstruction can also be due to iatrogenic stricture at the JJ anastomosis, port site hernia, and small bowel volvulus.
Deep vein thrombosis or pulmonary embolism is the commonest cause of death following gastric bypass. The thrombo-embolic disease accounts for half of all deaths following bariatric surgery. Prevention is critical, with intermittent calf pumps intra-operatively, compression stockings, and post-operatively pharmaceutical prophylaxis for at least one-week minimum.[rx]
Late Complications:
Internal herniation can occur in gastric bypass in one of three ways. A Peterson’s hernia can occur following herniation of the bowel through the defect created between the jejunal mesentery of the alimentary limb and the transverse mesocolon. The other two hernias can occur at the mesenteric defect created by the JJ anastomosis and through the mesocolic fault if the Roux limb passes retro colic. As weight is lost, the bowel anatomy changes, and mesenteric defects can become accentuated or created. The presentation is often sub-acute, with post-prandial pain or bloating; however, acute manifestations with strangulation can also occur. Internal hernias can occur in up to 7% of cases if defects created in the mesentery are not closed.[rx] Laparoscopy is the investigation of choice, with a reduction of the hernia and closure of the mesenteric defect.
Stricture at the GJ anastomosis can occur in 5% of patients. Contributing factors include excess tension and technical aspects of methods used to create the join.
Micronutrient deficiency can occur, and lifelong vitamin/mineral supplementation is essential for preventing these deficits caused by loss of absorption at the DJ region of the bowel.[rx] Common deficiencies include thiamine, vitamin B12, folate, iron, zinc, and vitamin D.
Rapid weight loss increases the odds of gallstone formation, which can occur in 30% of patients. Common bile duct stones in patients with a bypass are not manageable by endoscopic retrograde cholangiopancreatography (ERCP). Hence, on-table cholangiography is typically performed during laparoscopic cholecystectomy to exclude this. Otherwise, gallstone disease management should be as per established local protocols.
Dumping syndrome can present as post-prandial malaise precipitated by the rapid passage of food into the anastomosed jejunum at the GJ anastomosis.[rx] Management is typically conservative with advice on altering diet and decreasing the size of meals.
Failure to lose weight may occur despite a surgically well-performed procedure. Maintenance of weight loss after bypass can be challenging for some, usually due to renewed binge-eating behaviors in patients.[rx] Anatomical stretching of the gastric pouch and gastro-gastric fistulation can occur between staple lines of the gastric pouch and remnant, leading to increased capacity for food consumption.
