Roux-en-Y Gastric Bypass

Anatomy and Physiology

Anatomy of the Stomach

Located in the upper abdomen, below the diaphragm, and to the left of the midline, the stomach is positioned between the esophagus and the duodenum of the small intestine and comprises 5 regions:

• Cardia
  • Entry point for food from the esophagus into the stomach
  • Lies just distal to the gastroesophageal junction

• Fundus
  • Dome-shaped region lying above and to the left of the cardia

• Body
  • Largest portion of the stomach; connects to the fundus
  • Lies below the fundus and abuts the left diaphragm
• Antrum
  • Lower part of the stomach and connects to the stomach body
  • Holds partially digested food until it is ready to move contents into the small intestine

• Pylorus
  • Funnel-shaped region that connects the stomach to the duodenum
  • Connects to the stomach's body, leading to the narrower pyloric canal, which further connects to the duodenum
  • Smooth muscle pyloric sphincter regulates stomach emptying

The stomach's lesser curvature lies beneath the medial segments of the liver and includes the incisura angularis, which can be identified as the junction of the vertical and horizontal axes of the lesser curvature (marks the transition of the body to antrum). The greater curvature is the long left lateral border of the stomach from the fundus to the pylorus, which is connected to the greater omentum. The left border of the intraabdominal esophagus and the fundus meet at an acute angle termed the "angle of His." Posterior to the stomach lies the lesser sac, which is a potential space anterior to the pancreas and bordered by the splenic artery, spleen, left kidney, and transverse mesocolon.

The stomach wall has 5 layers:

• Mucosa
  • Innermost layer where nearly all stomach cancers originate
  • The mucosa has 3 parts:
    • An epithelial layer that contains glands and multiple cell types, including: 
      • Surface mucous cells
        • Secrete mucus to protect the gastric epithelium from acidic and enzymatic damage
      • Mucous neck cells
        • Produce mucus that lubricates and protects the gastric lining
      • Parietal cells
        • Secrete hydrochloric acid and intrinsic factor, essential for the absorption of vitamin B12
      • Chief cells
        • Produce pepsinogen, the inactive form of the enzyme pepsin, which aids in protein digestion
      • Enteroendocrine cells
        • Releases hormones such as gastrin, somatostatin, and histamine, which regulate gastric acid secretion and other digestive functions
    • A layer of connective tissue (the lamina propria)
    • A thin layer of muscle known as the muscularis mucosa

• Submucosa
  • Supporting layer beneath the mucosa

• Muscularis propria
  • Thick muscle layer that moves and mixes the stomach contents (eg, peristalsis)

• Subserosa
  • Layer of connective tissue containing blood vessels, lymphatics, and nerves

• Serosa
  • Outermost wrapping layer of the stomach

In its relaxed state, the stomach's mucosa and submucosa form folds known as rugae. 

Vascular Supply

The arterial blood supply to the stomach includes:

• Celiac trunk
  • This originates from the abdominal aorta and has 3 major branches: the left gastric, common hepatic, and splenic arteries.

• Common hepatic artery
  • This gives off the gastroduodenal artery, which runs behind the first portion of the duodenum. 

• Left gastric artery
  • This arises from the celiac trunk, runs along the superior portion of the stomach's lesser curvature, and anastomoses with the right gastric artery.

• Right gastric artery
  • This originates from the proper hepatic artery, which runs along the inferior portion of the stomach's lesser curvature and anastomoses with the left gastric artery.

• Left gastroepiploic artery
  • This arises from the splenic artery, runs along the superior portion of the stomach's greater curvature, and anastomoses with the right gastroepiploic artery.
  • This is the principal blood supply to the stomach after SG. 
  • This gives off many posterior branches, which should remain uninterrupted during the dissection of the stomach's posterior surface.

• Right gastroepiploic artery
  • This arises from the gastroduodenal artery, travels along the inferior portion of the stomach's greater curvature, and anastomoses with the left gastroepiploic artery.

• Short gastric arteries
  • These short arteries (usually 3-5) originate from the splenic and left gastroepiploic arteries to supply the stomach's greater curvature.
  • These are contained in the gastrosplenic ligament and go to the gastric fundus.

Venous Drainage

• The stomach's veins share names with the arteries.
• The right and left gastric veins drain directly into the hepatic portal vein, whereas the short gastric veins and the gastroepiploic veins drain into the superior mesenteric vein.

Ligamentous Attachments

The following ligaments are attached to the stomach to anchor it in place:

• Gastrocolic ligament
  • This portion of the greater omentum connects the stomach's greater curvature to the transverse colon, forms part of the anterior wall of the lesser sac, and contains the gastroepiploic vessels.

• Gastrosplenic ligament
  • This portion of the greater omentum connects the stomach's greater curvature to the splenic hilum and contains the left gastroepiploic and short gastric arteries.

• Gastrohepatic ligament
  • This peritoneal attachment connects the medial liver to the stomach's lesser curvature, forms part of the anterior wall of the lesser sac, and contains the right and left gastric arteries. A replaced left hepatic artery may also be included here.

• Gastrophrenic ligament
  • This peritoneal attachment connects the left hemidiaphragm to the superior portion of the stomach.

Innervation

The stomach receives innervation from both the sympathetic and parasympathetic nervous systems and local enteric neurons:

• Parasympathetic innervation
  • This is the main parasympathetic input to the stomach from the vagus nerve (tenth cranial nerve).
  • Vagal fibers innervate the stomach's smooth muscle layers and glands, stimulating secretion and motility.
  • Parasympathetic stimulation increases gastric activity, including the secretion of gastric juices and peristaltic contractions.
• Sympathetic Innervation
  • Sympathetic fibers reach the stomach via the greater splanchnic nerve and its branches, originating from the T6-T9 spinal cord segments.
  • Sympathetic stimulation inhibits gastric activity, including secretion and motility.
  • Sympathetic input also causes vasoconstriction in the gastric vasculature.
• Enteric Nervous System (ENS)
  • The stomach's intrinsic nervous system, the ENS, controls local reflexes.
  • The ENS regulates functions such as peristalsis, secretion, and blood flow within the stomach independently of the central nervous system.
  • The ENS consists of a complex network of neurons located within the walls of the gastrointestinal tract.
• Sensory Innervation
  • Sensory fibers, including those from the vagus nerve, convey information about distension, chemical composition, and other stimuli within the stomach to the central nervous system.
  • These sensory inputs are crucial in regulating appetite, triggering reflexes, and coordinating digestive processes.

Indications

Since the National Institutes of Health published its statement on gastrointestinal surgery for severe obesity in 1991, understanding obesity and metabolic and bariatric surgery (MBS) has significantly grown based on a large body of clinical experience and research. Long-term data results consistently demonstrate the safety, efficacy, and durability of MBS in the treatment of clinically severe obesity and its comorbidities, with a resultant decreased mortality compared with nonoperative treatment methods. In 2022, the American Society of Metabolic and Bariatric Surgery and the International Federation for the Surgery of Obesity and Metabolic Disorders wrote revised indications for MBS.[16] MBS is indicated for the following:

• Individuals with BMI ≥35 kg/m², regardless of presence, absence, or severity of comorbidities
• Patients with type 2 diabetes and BMI ≥30 kg/m²
• Should be considered in individuals with a BMI of 30 to 34.9 kg/m² who do not achieve substantial or durable weight loss or comorbidity improvement using nonsurgical methods
• Obesity definitions using BMI thresholds
  • Do not apply similarly to all populations
  • Clinical obesity in Asian populations: BMI >25 kg/m²  
    • Access to MBS should not be denied solely based on traditional BMI risk zones.
• Children and adolescents with a BMI >120% of the 95th percentile and major comorbidity, or a BMI >140% of the 95th percentile
  • Should be considered for MBS after evaluation by a multidisciplinary team in a specialty center.
• No upper patient-age limit 
  • Older individuals who could benefit from MBS should be considered for surgery after careful assessment of comorbidities and frailty.
  • Carefully selected individuals considered at higher risk for general surgery may benefit from MBS.
  • MBS is an effective treatment of clinically severe obesity in patients who need other specialty surgery, such as joint arthroplasty, abdominal wall hernia repair, or organ transplantation.

Consultation with a multidisciplinary team can help manage modifiable risk factors to reduce the risk of perioperative complications and improve outcomes. The surgeon should ultimately determine surgical readiness.

Contraindications

Relative contraindications to RYGB include:

• Inflammatory disease or condition of the gastrointestinal tract, including but not limited to:
  • Ulcers
  • Severe esophagitis
  • Crohn disease
• Uncontrolled and untreated psychiatric disorders, including but not limited to:
  • Substance and alcohol use disorders
  • Active psychosis
  • Recent history of suicide attempts
• Severe intellectual disability
  • Proving a high degree of patient understanding of surgery's risks and lifestyle implications 
• Epilepsy
  • Patients 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.[17]
• Allergic reactions to materials used during surgery
• Chronic, long-term steroid treatment
• Problems that could cause bleeding in the esophagus or stomach, including but not limited to:
  • Esophageal or gastric varices 
  • Congenital or acquired intestinal telangiectasia 
• Active infection in the body

Absolute contraindications to RYGB include:

• Pregnancy
• Patients with severe incapacitating systemic diseases, including endstage renal disease, unstable coronary artery disease, severe heart failure, cirrhosis, portal hypertension, and active malignancy [18]
• Patients who can not tolerate general anesthesia

Equipment

For an RYGB procedure, various equipment and instruments are necessary to perform the surgery safely and effectively. Some essential equipment includes:

• Anesthesia and monitoring equipment: Standard anesthesia delivery systems, monitoring devices (eg, electrocardiogram, pulse oximetry, blood pressure monitoring), and airway management equipment are needed to ensure the patient's safety and comfort throughout the surgery.
• Patient positioning equipment: Operating room tables, pads, and positioning aids ensure the patient is safely and comfortably positioned for the procedure.
• Laparoscopic tower: This will need to include a video monitor, camera (30° scope), insufflator, and light source.
• Trocars: Devices sized 5, 10, and 15 mm are needed.
• Surgical instruments: Scalpels, retractors, and forceps are needed to access the abdomen. Laparoscopic instruments such as a Nathanson liver retractor, graspers, dissectors, scissors, and clip appliers are also included.
• Staplers: Linear and circular staplers are used to create anastomoses and staple tissue during the reconstruction phase of the surgery.
• Suction/irrigation system: This system clears the surgical field of blood and debris and maintains a clear surgical view.
• Electrocautery devices: These devices are used for tissue dissection and hemostasis. They apply electrical current to coagulate blood vessels and seal tissue.
• Gastrointestinal measurement devices: Devices, including rulers or calibrated tubes, measure the length of the Roux and biliary limbs during bypass creation; these devices are optional based on surgeon preference. 
• Endoscopic equipment: This equipment may be used intraoperatively to visualize the gastric pouch and anastomoses and ensure their integrity; these are also optional based on surgeon preference. 
• Sutures: These are for closing the port sites.
• Dressing materials: A range of dressing materials may be employed.

Personnel

Essential personnel for a RYGB procedure include, but are not limited to:

• Bariatric surgeon
• Surgical first assistant
• Surgical technologist or operating room nurse
• Circulating or operating room nurse
• Anesthesia personnel

Preparation

Preparing patients for bariatric surgery, including RYGB, is a comprehensive multi-step process designed to ensure optimal outcomes and minimize risks. The preparation process requires collaboration among various healthcare professionals, including surgeons, primary care clinicians, dietitians, psychologists, anesthesiologists, and nurses, to ensure comprehensive care and optimal surgical outcomes. This preparation includes medical, nutritional, psychological, and lifestyle considerations.

Medical Evaluation and Optimization of Comorbidities

A thorough medical history and a comprehensive physical examination are required to identify and assess any underlying health conditions that must be addressed before surgery. This assessment should focus on evaluation for cardiovascular disease, respiratory disease, gastrointestinal conditions, and other obesity-related comorbidities. Laboratory studies should be conducted to identify nutritional deficiencies, including iron, vitamin B12, and folate deficiency. Liver and kidney function should be assessed.

The optimization of medical comorbidities is an important step in the preoperative care of patients undergoing RYGB. Medical optimization can reduce anesthetic risk, as assessed by the American Society of Anesthesiology grade. Particular focus should be paid to managing obstructive sleep apnea and type 2 diabetes.[1] Patients may undergo cardiac stress testing, echocardiography, or pulmonary function tests, especially if they have a cardiovascular or respiratory disease history. If the patient has diabetes, blood glucose levels must be well-controlled before surgery. This may involve adjustments in medication or insulin therapy. For a more comprehensive discussion of the preoperative assessment recommended for patients pursuing bariatric surgery, please see StatPearls' companion references "Bariatric Surgery Preoperative Assessment" and "Obesity Surgery Preoperative Assessment and Preparation."

Nutritional Assessment and Optimization

Patients undergoing bariatric surgery should have a preoperative consult with a registered dietician for a comprehensive assessment of preoperative eating habits and dietary counseling. Some preoperative weight loss is recommended to ensure the patient's willingness to follow a dietary plan and to help improve surgical outcomes. Patients may be advised to take specific vitamins and minerals such as multivitamins, vitamin D, and calcium to correct deficiencies and prepare for malabsorption after surgery. A preoperative liquid or low-calorie diet is often prescribed for 1 to 2 weeks before surgery to reduce liver volume and make the surgery safer and easier to perform. In some institutions, patients are initiated on a 2-week milk diet to reduce the liver size and constraints on laparoscopic instrument movement.[19] 

Psychological Evaluation and Support

A mental health professional performs a psychological evaluation to assess the patient's mental health status and readiness for surgery. This includes screening for eating disorders, depression, anxiety, and other psychological conditions. Patients may receive counseling to address emotional eating, stress management, and developing healthy coping strategies. Support groups or therapy sessions can provide ongoing support before and after surgery.

Lifestyle Modifications

Patients are advised to quit smoking at least several weeks before surgery to reduce the risk of complications such as infections, poor wound healing, and respiratory issues. An exercise regimen tailored to the patient's abilities is recommended to improve physical fitness and enhance surgical outcomes.

Preconception Counselling and Pregnancy Timing

The main concern of pregnancy in the early postoperative period after bariatric surgery is that the developing fetus could be affected by rapid weight loss and potential micronutrient deficiencies. Women of childbearing age are recommended to postpone pregnancy during the period of rapid weight loss until a stable weight is achieved. This is typically achieved 1 year after RYGB. These patients require adequate counseling regarding safe and effective contraception. As obesity is associated with impaired fertility due to metabolic syndrome and polycystic ovarian syndrome, patients may not be using contraception presurgery. They should be made aware that fertility increases postoperatively, and contraception usage should be discussed.[20]

The physiologic and anatomic changes of bariatric surgery may augment the risk of oral contraceptive failure. Oral contraceptive pills also increase the risk of thromboembolism in patients with obesity. The American College of Obstetricians and Gynecologists recommends using nonoral hormonal contraception (eg, levonorgestrel intrauterine system or implants) for women who undergo bariatric surgery and desire hormonal contraception.

Education and Informed Consent

Patients attend educational sessions to learn about the surgical procedure, the risks and benefits, postoperative care, and the lifestyle changes required after surgery. Detailed discussions are held regarding the risks, benefits, and alternatives to surgery. Patients must provide informed consent, indicating their understanding and agreement to proceed with the surgery. Please see StatPearls' companion reference, "Counseling Patients on Bariatric Surgery for Obesity" for further discussion.

Preoperative Procedures

Patients may need to undergo a bowel preparation regimen in the immediate preoperative period, depending on the surgeon's preference. Patients should receive instructions on which medications to take or avoid before surgery, including guidelines on managing blood thinners and other chronic medications. Instructions are provided regarding fasting before surgery (typically nil per os after midnight on the day of surgery) and what to expect during the hospital admission. On the day of the surgery, the patient receives venous thromboembolism prophylaxis, and compression stockings or intermittent pressure calf compression devices are applied bilaterally. The patient will also receive medications to aid in nausea and gastroesophageal reflux disease control. 

Technique or Treatment

Technological advancements, such as enhanced visualization of the surgical field and finer instruments, have led to the widespread adoption of laparoscopic techniques, which offer shorter recovery times and reduced postoperative pain. Laparoscopic surgery is now the standard for MBS, with robotic-assisted methods emerging as a highly effective option, especially for complex cases. Currently, the percentage of laparoscopic surgeries remains high at 96.2% to 98.8% of the cases.[21] Traditional laparoscopic surgery has limitations, such as 2-dimensional visualization, rigid instruments, and poor ergonomics.

Due to further surgical advancements and the introduction of innovative technology, the robotic approach has been deemed an advantageous alternative for complex procedures. The robotic approach could overcome limitations with improved ergonomics, camera control, 3-dimensional visualization, and flexible endowristed instruments.[22][23][24] Despite its advantages in handling complex anatomy and overcoming laparoscopic limitations, the long-term efficiency and role of the robotic approach in MBS are not well-documented in the current literature. Zhang et al reported that while robotic bariatric surgery was associated with longer operative time, there was a similar safety and efficacy profile compared to laparoscopic bariatric surgery.[25] 

Whether an RYGB is performed laparoscopically or robotically, the steps remain the same, although techniques vary between surgeons, and there is no established standardization. The steps of RYGB include creating a gastric pouch, creating a biliopancreatic limb, creating a jejunojejunostomy, and creating a gastrojejunostomy. An example is as follows:

Preparation and Anesthesia

The patient is placed under general anesthesia and then positioned in a modified lithotomy position with the legs apart. The patient is then prepped and draped. The lead operating surgeon stands between the legs, and the monitor is positioned above the patient's head. 

Port Placement

The abdomen is accessed and insufflated. Several ports are inserted under direct visualization for the laparoscopic instruments and camera, typically 1 for the camera and 3 to 4 for the instruments.

Gastric Pouch Creation

Adequate exposure of 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 retrogastric 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. Linear endoscopic staplers begin transversely at the inferior border of the oblique fat pad, taking a 2- to 3-cm bite and then firing vertically towards the angle of His. MacLean et al demonstrated that the optimal gastric pouch is 20 to 30 mL in volume and primarily involves the lesser curve of the stomach. Long-term follow-ups have shown steady weight loss over 15 years with this technique.[26] 

Creation of the Biliopancreatic Limb

The biliopancreatic limb, also known as the afferent limb, consists of the duodenum and proximal jejunum, which remain in continuity with the remnant stomach proximally. The limb contains digestive enzymes from the stomach, hepatobiliary tract, and pancreas. Approximately 50 to 75 cm is measured starting at the ligament of Treitz and divided using a stapling device to create the biliopancreatic limb. 

Creation of Jejunojejunostomy

The Roux limb is measured 100 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 anastomosis. This connection allows bile and pancreatic juices to mix with the ingested food in the Roux limb.

Creation of Gastrojejunostomy

The Roux limb of the jejunum can then be brought up either in an antecolic-antegastric or a retrocolic-retrogastric orientation. A side-to-side gastrojejunostomy (GJ) is then created using a linear stapling device with suture closure of the defect. Suppose the anastomosis is performed in a retrocolic pattern. In that case, it is essential to recognize the transverse mesocolon defect (Petersen space) that could be a potential site of internal herniation of intestinal loops. Closing the mesenteric defects of the biliopancreatic, Roux limb, and transverse mesocolon thus obliterates this potential hernia site.

Leak Test

Before the procedure is completed, an upper endoscopy leak test is performed while keeping the GJ in view. The gastric pouch and GJ are submerged in saline with the patient in Trendelenburg. An endoscope is advanced across the GJ 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.[27] Any leaks are repaired as necessary.

Closure

The pneumoperitoneum is released, and port sites are closed as usual.

Postoperative Care

The patient is brought out of anesthesia and taken to the recovery area. Postoperative care includes pain management, monitoring for complications, and initiating a staged diet beginning with clear liquids. Protocols vary concerning postoperative care and length of stay. An overnight stay is recommended to be safe for most patients, according to results from a study.[28] Same-day discharge has been shown to correlate with increased morbidity and mortality, and hence, most centers avoid it.[29] With an improved understanding of optimal patient recovery after surgery and the advent of enhanced recovery after surgery, many patients are now going home within 2 to 3 days following bariatric surgery.[30]

Complications

Bariatric surgery is an effective treatment for severe obesity, but it carries the potential for various complications, both early (less than 30 days) and late (more than 30 days).[4] The mortality from RYGB is roughly 0.2%, higher than sleeve gastrectomy and gastric banding.[31] 

Early Complications

Anastomotic leak

The incidence of anastomotic or staple line leaks after RYGB varies from 0.4% to 5.2%, primarily occurring at the GJ anastomosis. Anastomotic leaks have the potential to drastically raise morbidity and death rates, making them possibly the most worrisome complication of any bariatric surgery.[4] Patients with postoperative leaks commonly experience a particular set of symptoms, such as persistent tachycardia, dyspnea, fever, left shoulder pain, and abdominal pain. These typically manifest within 3 days (early) but can occur after 5 days (late).[32] 

The evaluation of a suspected anastomotic leak includes either an abdominal computed tomography (CT) evaluation with oral contrast or an upper gastrointestinal series. Notably, 60% to 80% of leaks at the GJ are diagnosed on CT, even without contrast extravasation.[32] An upper gastrointestinal series may be performed to find leaks at the GJ, but this study is less accurate than CT. However, after an RYGB, neither CT nor upper gastrointestinal imaging is useful for excluding a leak at the jejunojejunostomy.

In hemodynamically unstable patients, those with persistent tachycardia, and those who show signs of sepsis, surgical exploration is typically used for both diagnosis and treatment. Understanding the key distinctions between sleeve gastrectomy (SG) leaks and RYGB leakage is critical. SG leaks happen in a high-pressure environment, frequently at the sleeve's topmost point, where the blood supply is weak. As opposed to SG, RYGB produces a low-pressure gastric pouch, which lowers the incidence of leaks (between 0.6% and 4.4% of patients). Because of this pressure differential, nonoperative management techniques can successfully handle RYGB leaks without sealing or repairing the perforation. Treatment options include conservative or surgical management.

Conservative management of an anastomotic leak is usually employed in stable patients with late, more insidiously developing leaks. The patient is kept on a nothing-by-mouth status to reduce gastric contents and minimize the ongoing leak, and broad-spectrum intravenous antibiotics are initiated. Patients may require total parenteral nutrition to support their nutritional needs while oral intake is withheld. Proton pump inhibitors are often administered to reduce gastric acid secretion and promote healing of the anastomotic site. If the leak has led to a localized fluid collection or abscess, image-guided percutaneous drainage may be performed. In some cases, endoscopic placement of a covered stent can help seal the leak and promote healing, especially when the leak is small and contained. Endoscopic clipping or suturing may also be considered for very small leaks. Endoluminal treatments, including clip placement, stents, or vacuum dressings, might be considered to help stop persistent RYGB leaks that continue for more than 30 days.[33] 

Surgical management is employed in early leaks and in patients showing signs of sepsis or hemodynamic instability. The surgical priorities include removing contamination (abdominal washout), controlling the leak with closed suction drains, and establishing feeding access. Repairing the leak is optional, depending on its feasibility and the patient's condition.

Hemorrhage

Postoperative hemorrhage typically stems from anastomoses and staple lines, and it must be determined whether the bleeding is intraluminal or extraluminal. Significant postoperative bleeding, requiring blood transfusion, occurs in approximately 1% to 4% of patients.[34] Symptoms of bleeding include a falling hematocrit, which occurs universally to some extent for all postoperative patients, and tachycardia, which often draws the clinician to concern about a leak. More definitive evidence for bleeding includes melena, hematochezia, or hematemesis, signifying an intraluminal bleed, or sanguineous drain output, representing bleeding into the peritoneal cavity. Blood per rectum usually suggests a more distal source like the gastric remnant or jejunojejunostomy.

For the stable patient, bleeding management begins with discontinuing anticoagulants, volume resuscitation with blood transfusion if indicated, and serial monitoring of the hematocrit. If the bleeding is ongoing and believed to be intraluminal, an esophagogastroduodenoscopy (EGD) should be performed after intubation in the operating room to confirm the diagnosis and endoscopic treatment. If an endoscopic intervention fails or the bleeding is extraluminal, the patient should then be surgically explored.

Those who are unstable should be transferred to the intensive care unit for resuscitation with blood transfusion before proceeding to the operating room. An EGD should follow intubation and, if necessary, emergent laparoscopy for bleeding control. If operative exploration is indicated due to concerns such as bleeding from the gastric remnant staple line, clinicians should consider staple line disruption as a potential cause and assess thoroughly for any concurrent leak. Fortunately, for most patients, significant bleeding after RYGB is self-limited and can be managed with transfusion alone, close monitoring, and discontinuation of any anticoagulants. There is some evidence that staple line reinforcements with RYGB reduce operative blood loss and significantly improve postoperative hemoglobin levels.[35]

Obstruction

GJ obstruction: This can present as early as the first postoperative day, with intolerance of liquids and nonbilious emesis, as well as severe obstruction and intolerance of secretions. Patients may note epigastric pain and fullness relieved with emesis. This early obstruction is generally due to edema or a clot at the GJ. This is rarely due to a technical error. An upper gastrointestinal (UGI) series will show the pouch filling with delayed passage of contrast through the GJ in a partial obstruction. The pouch fails to empty, and symptoms are often reproduced during the UGI with a complete obstruction. Radiographically evident obstruction occurs at a reported rate of 0.97%. Management includes nothing-by-mouth (NPO) status until symptoms improve, followed by a trial of liquids; if prolonged NPO status is needed, total parenteral nutrition should be initiated by postoperative day 5 or placement of a fluoroscopically guided GJ or gastric tube in the remnant stomach. Operative intervention is rarely required.

Jejunojejunostomy obstruction: This may present as Roux limb obstruction with nausea, vomiting, and epigastric fullness symptoms. Acute biliopancreatic remnant obstruction can present more subtle findings than Roux limb obstruction, including epigastric abdominal pain and tachycardia or bradycardia (due to gastric distention). Laboratory findings may suggest biliary and pancreatic duct stasis, such as elevated alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and total and direct bilirubin or lipase. A CT scan can help diagnose biliopancreatic limb obstruction, as a plain abdominal x-ray can miss a fluid-filled and distended biliopancreatic limb. Operative intervention is often required with clinical findings of a jejunojejunostomy (JJ) obstruction, as this is generally a technical failure and requires surgical correction to relieve the obstruction. Early JJ obstruction may be due to narrowing or kinking of the anastomosis or a coagulated blood clot with edema of the staple line, resulting in proximal limb obstruction. If the JJ obstruction is causing acute obstruction of the biliopancreatic limb, early and rapid decompression is critical regardless of the etiology. Delayed decompression places the patient at risk of staple line blow-out and remnant perforation. Decompression can be managed most easily by placing a gastric tube into the gastric remnant.

Venous thromboembolic disease

This is the most common cause of death following RYGB; of all deaths occurring following bariatric surgery, thromboembolic disease accounts for half. Prevention is critical, with intermittent calf pumps intraoperatively, compression stockings, and postoperatively pharmaceutical prophylaxis for at least 1-week minimum.[36]

Infections

Due to several variables, such as the surgical site itself and comorbidities associated with obesity, patients following weight reduction surgery may be at an elevated risk for infections. One of the most typical infections linked to bariatric surgery is surgical site infection; these infections may develop in the abdominal cavity or incision site(s). Obesity, diabetes, prolonged surgery, and poor glycemic control are risk factors for surgical site infections.[37]

Late Complications

Internal herniation

Internal hernia is one of the most frequent long-term complications after laparoscopic RYGB and usually occurs metachronously after relevant weight loss.[38] As weight is lost, the bowel anatomy changes, and mesenteric defects can become accentuated or created. Surgical treatment of an internal hernia has risks that the implementation of institutional standards and a structured approach can largely avoid.[39] While the occurrence of an internal hernia after RYGB can be reduced by sufficient closure of mesenteric defects, their overall occurrence remains high.[38] Internal hernias can occur in up to 7% of cases if defects created in the mesentery are not closed.[40] 

Internal hernias can have a wide variety of manifestations, ranging from mild abdominal discomfort to severe abdominal pain that resembles small bowel obstruction. The duration determines the severity of symptoms, reducibility of the bowel segment, and the presence or absence of strangulation and incarceration.[41] Rapid detection of such conditions is life-saving, as it can cause potentially fatal consequences that require emergency surgery if left undiagnosed.[42]

Internal hernias can occur after RYGB in 1 of 3 ways:

• Peterson hernia
  • This may occur following bowel herniation through the defect created between the jejunal mesentery of the alimentary limb and the transverse mesocolon. The estimated incidence ranges from 0.9% to 4.5%.
• The mesenteric defect created by the JJ anastomosis
• The mesocolic defect if the Roux limb passes behind the colon

Laparoscopy is the investigation of choice, with a reduction of the hernia and closure of the mesenteric defect. 

Stricture

A stricture usually occurs at the GJ anastomosis and can occur in up to 5% of patients. Strictures typically present a few months after surgery and can become chronic issues. Endoscopy is the preferred diagnostic method, and endoscopic dilation is the treatment of choice. Serial endoscopic balloon dilations of no more than 3 mm to 4 mm with each treatment are recommended. If repeated dilations fail, revisional surgery may be needed.

Micronutrient deficiency

Lifelong vitamin and mineral supplementation is essential for preventing the deficits caused by absorption loss at the duodenojejunal bowel region.[43] Common deficiencies include thiamine, folate, B2, B3, B6, B12, vitamins D and A, calcium, copper, and zinc.[44] Iron deficiency is highly prevalent after RYGB, affecting approximately 33% of patients, mainly in menstruating women.[24] Calcium, vitamin D, iron, folate, and vitamin B12 are recommended supplements. The frequency of vitamin-level monitoring should be every 3 to 6 months in the first year, 6 to 12 months in the second year, and 12 months in the third year postsurgery.[45] Please see StatPearls' companion reference "Bariatric Surgery Malnutrition Complications" for further information.

Hyperoxaluria

Typically, individuals absorb only about 10% of dietary oxalate, whereas, after RYGB, the expected dietary oxalate absorption rises to about 40%. Patients can develop severe enteric hyperoxaluria after RYGB. A potential mechanism for hyperoxaluria after RYGB is enhanced saponification of intestinal calcium with unabsorbed fatty acids due to fat malabsorption.[46][47] There is also a lack of available oxalate binding agents that would limit this increased absorption. 

Enteric hyperoxaluria greatly increases the urinary oxalate level (by about 50%), significantly raising the risk for calcium oxalate stone production, particularly in patients with a history of stones.[47] Even relatively low urinary calcium levels cannot prevent calcium oxalate stone formation. Most patients with enteric hyperoxaluria also benefit from increased fluids and potassium citrate supplementation. Patients with a history of kidney stones should undergo a 24-hour urine test to identify correctable risk factors after any RYGB.

The most important and effective oxalate binder is calcium. Calcium citrate (without vitamin D) is the suggested calcium supplement. Vitamin D is discouraged as the intention is to keep the calcium within the digestive system to act as an oxalate binder.

Other treatments for enteric hyperoxaluria include pyridoxine, cholestyramine, and iron, which can substitute for calcium in selected cases. Due to bicarbonate loss, citrate supplements are usually also required. In some cases, bypass surgery may need to be reversed to stop kidney stone production.

Gallstone formation

Rapid weight loss increases the odds of gallstone formation, which can occur in 30% of patients. Common bile duct stones in patients who have had an RYGB are not manageable by endoscopic retrograde cholangiopancreatography because the sphincter of Oddi cannot be cannulated endoscopically. Hence, on-table cholangiography is typically performed during laparoscopic cholecystectomy to exclude this. If the cholangiogram is positive, then common bile duct exploration should be performed. Gallstone disease management should follow established local protocols. Many bariatric institutions advocate cholecystectomy before bariatric surgery.

Dumping syndrome 

Dumping syndrome develops when hyperosmolar chyme passes through the small intestine too rapidly.[48] Dumping syndrome most commonly occurs after RYGB due to the rapid emptying of the small gastric pouch into the jejunum via the GJ anastomosis. The inherent pyloric valve is bypassed during this procedure, allowing food to pass straight into the small intestine. This fast transit might result in many systemic and gastrointestinal symptoms. The 2 types of dumping syndrome are early and late.

Early dumping syndrome presents symptoms such as nausea, vomiting, stomach cramps, diarrhea, and flushing, typically occurring 10 to 30 minutes after eating. This is often triggered by the rapid entry of undigested food into the small intestine. Late dumping syndrome typically occurs 1 to 3 hours after eating and is characterized by symptoms like sweating, weakness, dizziness, and palpitations. This is brought on by reactive hypoglycemia, which happens when too much insulin is released due to a sudden glucose inflow in the small intestine.

Managing dumping syndrome involves dietary modifications and medication. Patients are instructed to consume smaller, more frequent meals and avoid sugar-rich diets. Complex carbohydrates and proteins may be better tolerated. In late dumping syndrome, medications such as acarbose or somatostatin may be administered to slow down digestion and lower the risk of hypoglycemia.[4] Please see StatPearls' companion reference, "Dumping Syndrome," for further discussion.

Marginal ulcers

Marginal ulcers, characterized by ulcerations near the GJ, are a known complication of RYGB surgery, with a mean prevalence of 4.6%.[49][50][51] Patients can present with a nonperforated ulcer and the classic symptoms of epigastric pain, nausea, and emesis, or less commonly with melena or hematemesis. Alternatively, the ulcer may perforate and cause an urgent presentation. The timing and severity of presentation often determine the course of treatment.

The increased size of the gastric pouch, the presence of a gastrogastric fistula, and the use of a nonabsorbable suture are all mechanical risk factors for the development of marginal ulcers. Other risk factors include but are not limited to, nonsteroidal anti-inflammatory drugs (NSAIDs), tobacco use, alcohol use, Helicobacter pylori infection, diabetes, immunosuppression, and gastroesophageal reflux disease.

Endoscopy is often used to diagnose marginal ulcers because it provides a clear view of the affected region.[49] Other treatment options include PPIs, quitting smoking, and refraining from using NSAIDs and alcohol. When ulcers persist or resist medicinal therapy, the underlying problem may need to be addressed surgically. Omental patch repair has been established as an effective surgical option for perforated marginal ulcers, while GJ revision is preferred in an elective setting or urgently without hemodynamic instability.

Gastrogastric fistula

A GG fistula is an abnormal connection between the surgically created pouch and the excluded remnant stomach; the estimated incidence ranges from 1% to 6% of patients undergoing RYGB with a divided stomach (historically, the stomach was stapled and left undivided, leading to an unacceptable rate of GG fistula).[52] The etiologies of a GG fistula include incomplete stomach transection, anastomotic leak, marginal ulcer perforation, and foreign body erosion. 

Patients may be completely asymptomatic or present with nonspecific symptoms, including abdominal pain, nausea, vomiting, gas bloat, pyrosis, and inadequate weight loss or weight regain.[53] Diagnosis is usually confirmed with a CT scan or UGI study. Treatment of GG fistula will include a proton pump inhibitor for all patients. While asymptomatic and mildly symptomatic individuals can generally be treated conservatively, the optimal management strategy for patients with severe or persistent symptoms is yet to be defined. Several treatment strategies (including endoscopic, surgical, and combined procedures) have been proposed to manage these patients.[52] Endoscopic treatments of small fistulae with clips may be successful; however, surgical treatment is usually necessary. Surgical options include remnant gastrectomy, transection of the fistulous transect, and revision of the GJ.

Failed weight loss maintenance

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.[54] Anatomical stretching of the gastric pouch and GG fistulation can occur between staple lines of the gastric pouch and remnant, leading to increased capacity for food consumption.

Clinical Significance

RYGB has proven to be highly effective in reducing comorbidities associated with obesity, along with facilitating significant weight loss. Patients undergoing RYGB typically lose 60% to 70% excess body weight. A landmark study's results published in the New England Journal of Medicine demonstrated that 12 years postsurgery, patients maintained a substantial mean weight loss of 35 kg. This long-term weight reduction significantly surpasses that seen in nonsurgical groups, who showed minimal to no weight loss over the same period.[55]

The impact of RYGB on comorbidities is particularly notable in the management of type 2 diabetes, hypertension, and hyperlipidemia. The same NEJM study's results reported a 51% remission rate for type 2 diabetes 12 years after surgery.[55] These findings are consistent with meta-analyses indicating that RYGB and SG offer superior long-term weight loss and diabetes remission compared to gastric banding and medical therapy. The anatomical and physiological changes after RYGB, including reduced caloric intake and hormonal adjustments, significantly decrease HbA1c and fasting glucose levels, thereby reducing the burden of diabetes-related complications.[7]

Additionally, RYGB has shown efficacy in reducing hypertension and improving lipid profiles. However, while triglyceride levels improve significantly, cholesterol management remains complex, with varying high-density and low-density lipoprotein levels. This variability highlights the nuanced nature of lipid metabolism postsurgery. Despite these mixed results, the overall improvement in comorbid conditions, including hypertension and hyperlipidemia, tends to be greater with RYGB than with sleeve gastrectomy, making RYGB the preferred surgical option for comprehensive comorbidity reduction.

Overall, RYGB offers durable and significant health benefits beyond weight loss, positioning it as a crucial intervention for individuals with morbid obesity and related comorbidities. These benefits underscore the importance of considering RYGB for weight management and its substantial impact on improving and potentially resolving obesity-related health issues.[56]

Enhancing Healthcare Team Outcomes

Successfully caring for patients after an RYGB procedure requires a well-coordinated, multidisciplinary approach involving obesity medicine clinicians and advanced clinicians, bariatric nurse specialists, pharmacists, dietitians, psychologists, and physical therapists. Skills and strategies must include comprehensive preoperative assessments, meticulous surgical techniques, and rigorous postoperative care protocols. Clinicians should focus on patient selection, evaluating medical history, and identifying potential contraindications.

Surgeons must employ advanced laparoscopic skills to minimize complications and ensure optimal surgical outcomes. Bariatric nurse specialists are crucial in patient education, preoperative preparation, and postoperative care, including monitoring for complications and promoting early mobilization. Pharmacists are essential for managing perioperative medications, including pain management and prophylactic antibiotics, and addressing potential nutritional deficiencies.

Effective interprofessional communication and care coordination are pivotal in enhancing patient-centered care, improving outcomes, and ensuring patient safety. Regular interdisciplinary meetings and clear communication channels help align treatment plans and address patient needs holistically. Dietitians and psychologists provide critical support for lifestyle modifications and mental health, addressing behavioral changes essential for long-term success. Many patients are also encouraged to attend support groups.[57]

Physical therapists assist with developing tailored exercise programs to promote recovery and sustained weight loss. Coordinated follow-up appointments and continuous monitoring are essential to detect and manage complications early, reinforce dietary and lifestyle changes, and provide ongoing support. The team educates the patients on various operations, their implications, reversibility, and complications.[58] This collaborative approach enhances team performance and significantly improves the quality of life and health outcomes for RYGB patients. The workup and interprofessional care for this operation include bariatric surgeons, endocrinologists, gastroenterologists, dieticians and nutritionists, and ward teams consisting of doctors, nurses, pharmacists, health care assistants, and administrative staff.

Nursing, Allied Health, and Interprofessional Team Interventions

Nursing care for bariatric individuals requires specialized attention and equipment to accommodate their size and needs. This includes larger blood pressure cuffs, hospital gowns, anti-slip socks, compression stockings, beds, and bedside commodes. Equipment such as chairs, beds, wheelchairs, and toilets must have adequate weight capacity. Due to their relative immobility, bariatric individuals are at increased risk of pressure sores, making it crucial to thoroughly assess, document, and monitor skin integrity in pressure areas. These areas need regular evaluation and care to prevent hospital-acquired sores during the inpatient stay.

Encouraging postoperative mobilization and involving physiotherapy and occupational therapy are essential. Manual handling training should focus on the specific needs of bariatric patients, including hoist transfers, and these requirements should be communicated to nursing staff before elective admission. In the event of a patient's death, early communication with the morgue ensures appropriate care of the deceased.

Nursing, Allied Health, and Interprofessional Team Monitoring

Nursing care is crucial to monitoring or evidence of surgical complications postoperatively. Nursing staff should understand the complications, including anastomotic leaks, hemorrhage, and bowel obstruction. The surgical team should be notified of any persistent tachycardia, sudden onset of abdominal or left shoulder pain, fever, and decreased urine output because these can suggest a leak. Severe abdominal pain, distension, and vomiting could be symptoms of a bowel obstruction.