Bariatric Surgery Complications

Function

Bariatric surgery can be either purely restrictive, such as the adjustable gastric band, or both restrictive and malabsorptive, as seen in procedures like the Roux-en-Y gastric bypass (RYGB) and laparoscopic sleeve gastrectomy (LSG). Other procedures, like the duodenal switch and biliopancreatic diversion, are exclusively malabsorptive. These surgeries play a crucial role in addressing the metabolic syndrome commonly associated with morbid obesity, which includes systemic conditions like diabetes, hypertension, and dyslipidemia that contribute to end-organ damage and significantly elevate morbidity and mortality. Procedures with a malabsorptive component specifically influence glucose metabolism, insulin sensitivity, and insulin clearance.[5][6] Bariatric surgery has been shown to offer more significant weight loss and improved metabolic outcomes than caloric restriction alone. For instance, gastric banding improves hepatic insulin sensitivity and lipolysis, while combined restrictive and malabsorptive procedures enhance insulin sensitivity in adipose tissue and reduce plasma insulin concentrations.[7]

LSG involves removing 60% to 70% of the stomach along the greater curvature, leaving a sleeve-shaped stomach with a reduced capacity of about 4 oz, which limits food intake. This procedure also accelerates gastric emptying.[8][9] The excision of the greater curvature reduces plasma ghrelin levels, a hormone influencing hunger, leading to decreased appetite for most patients.[10] In contrast, RYGB creates a small stomach pouch, bypassing a portion of the stomach and the small intestine, and alters the mix of digestive enzymes. Study results show that a longer biliopancreatic limb leads to greater weight loss and improved glucose handling than a longer Roux limb.[11]

Insulin resistance improves with bariatric procedures through alterations in nutrient absorption and delayed gut hormone release, which directly impact pancreatic beta-cell function. While LSG and RYGB modify nutrient absorption, they lead to distinct changes in hormonal secretion and nutrient dynamics, particularly affecting peptide production.[12] Bariatric surgery can also cause chronic conditions or issues requiring ongoing management. During extensive preoperative screening and education, the known adverse events are discussed with patients, covering crucial practices such as dietary changes, smoking cessation, and strategies for preventing gastroesophageal reflux and ulcers. 

Issues of Concern

Complications

Bariatric surgery is associated with immediate and long-term complications, which require careful monitoring and management. Some study results demonstrate a correlation between postoperative complications and comorbidities but have no association with surgical approaches or equipment.[13] Anastomotic leaks and bleeding can occur either immediately or later postoperatively, and their management depends on the scope and severity of the issue. Bleeding is the most common immediate complication, reported at 2.7% for RYGB and between 0.6% to 2.3% for LSG. Bleeding may be gastrointestinal or intraabdominal, and the need for intervention—either endoscopic or surgical—depends on the location.[4][14] Postoperative bleeding is associated with diabetes, chronic kidney failure, cardiovascular disease, and antiplatelet therapy.[4][15] 

The incidence of leaks after LSG ranges from 1.5% to 3%, while for RYGB, the incidence falls between 0.3% and 2%.[16][17] Leaks that manifest a few weeks after surgery are often near the gastroesophageal junction and may result from thermal injury during surgical dissection. In sleeve gastrectomy, narrowing of the proximal sleeve can lead to pressure-related blowouts. Leaks following gastric bypass may stem from gaps in stapled or hand-sewn suture lines, thermal injury, or distal obstruction, commonly due to narrowing at the entero-entero anastomosis or complications like internal hernias or adhesions. Results from a meta-analysis of patients with RYGB revealed that a history of pulmonary embolus and partially dependent functional status are significant predictors of postoperative leaks, while increased albumin levels appear protective.[18] Endoscopy, often with contrast instillation, is commonly used to assess for leaks, and many centers incorporate postoperative contrast imaging.[19]

Leaks that present later typically exhibit milder symptoms, such as abdominal pain and tachycardia. These cases are often managed nonoperatively with bowel rest, image-guided drainage of abscess collections, and the placement of an indwelling drain. Supplemental parenteral nutrition or tube feeding distal to the leak may be provided if necessary. Larger leaks can present with more severe symptoms, including marked abdominal pain, tachycardia, fever, leukocytosis, and visible free extravasation of contrast on imaging. In these cases, endoscopic stenting or surgical intervention is effective for managing peritonitis. For patients with recurrent leaks following LSG, conversion to RYGB may be considered an alternative to repeated attempts at sleeve repair. Using buttressed staple lines and suture reinforcements has significantly reduced the incidence of staple line complications and sleeve leaks.[20] Patients who successfully repair sleeve gastrectomy leaks experience weight loss and resolution of comorbidities comparable to those without leak-related complications.[21] 

RYGB is associated with a higher incidence of complications. An internal hernia can occur through a defect between the bypass limbs, transverse mesocolon, and retroperitoneum posterior to the Roux limb mesentery, or through a trocar site hernia, or any location where a gap is left in the mesentery.[22] Intusussusception at the level of the jejunojejunostomy can also cause obstruction. This can be prevented by affixing the 2 ends with a nonresorbable suture while creating this anastomosis. This technique, also known as the "Brolin stitch," can be the source of an obstruction if improperly performed. Significant weight loss may alter the anatomical relationship of intraabdominal contents, creating a greater potential for an internal hernia. Internal hernias may result in catastrophic strangulation if not identified and corrected. Diagnosis is usually made on a computed tomography scan with contrast or diagnostic laparoscopy.[23]

Marginal ulceration, occurring at the gastrojejunal anastomosis, has a reported incidence of 4.6% and is a possible complication following RYGB. Several mechanisms have been proposed, including the impact of gastric acid secretions on jujunal mucosa. The formation of a gastro-gastric fistula may also promote ulceration. Other factors that impair tissue perfusion may lead to ulceration, including smoking, nonsteroidal antiinflammatories, or Helicobacter pylori infection. A larger gastric pouch may contain more acid-producing parietal cells and, therefore, be more prone to ulcer formation.

Ulcers can cause strictures, bleeding, or a leak, but some persons with ulcers may be asymptomatic. The time interval for presentation varies between 1 month to 6 years. Treatment ranges from pharmacologic therapy with proton pump inhibitors and sucralfate to endoscopic stenting, coagulation, or clipping of bleeding sites or oversewing the ulcer. Those who have ulcers that are refractory to other therapies require surgical correction. Surgical modification may include anastomotic revision with or without vagotomy, gastrectomy, or conversion to sleeve gastrectomy. Perforations may be treated with a patch or anastomotic revision, and strictures can be addressed with dilation, stenting, or revision. The recurrence rate of marginal ulcers is around 5%.[24][25]

LSG can cause or exacerbate gastroesophageal reflux. Because of the smaller gastric volume, the intraluminal pressure within the stomach may worsen reflux symptoms. The disturbance of the lower esophageal sphincter may also contribute to esophageal acid exposure. Uncontrolled reflux can lead to Barrett esophagus and esophageal adenocarcinoma. All potential patients undergoing bariatric surgery have preoperative endoscopy and are placed on a proton pump inhibitor for at least 1 year postoperatively. Endoscopy is performed for anyone exhibiting postoperative reflux symptoms. Conversion to RYGB may improve symptomatic reflux or silent reflux with endoscopic identification of acid-mediated damage to the esophagus.[8][9]

Gallstones are a well-documented complication following bariatric surgery, particularly after procedures that result in significant weight loss, such as the RYGB and LSG. The rapid and substantial weight loss after these surgeries increases the risk of gallstone formation due to changes in bile composition and the way bile is stored and secreted. Weight loss leads to a decrease in the gallbladder volume, which can cause bile to become more concentrated, promoting the formation of gallstones. Furthermore, significant caloric restriction after bariatric surgery can result in a higher rate of bile stasis and a decrease in the motility of the gallbladder, further contributing to the development of gallstones.

The incidence of gallstones after bariatric surgery varies, with studies reporting rates of 10% to 25% or more in patients who experience rapid weight loss. Symptoms may range from mild, such as epigastric discomfort or nausea, to severe, including biliary colic, cholecystitis, or even pancreatitis if a stone obstructs the bile duct. Because of this increased risk, prophylactic cholecystectomy is often considered during bariatric surgery, particularly in patients with obesity-related comorbidities, to prevent future gallstone-related complications. If gallstones develop postoperatively, management typically includes surgery, ie, laparoscopic cholecystectomy, if symptoms or complications arise. Given the increased risk of gallstones, early detection and management are key to preventing long-term complications in post-bariatric surgery cases.

Venous thromboembolism is a risk for those undergoing surgery, and the risk increases in those with obesity. The rate of a thromboembolic event for those undergoing bariatric surgery is 0.3% to 2.4%. While uncommon, venous thromboembolism contributes to significant morbidity and mortality. Embolic events can include deep vein thrombosis, pulmonary embolism, or mesenteric thrombosis. Obesity is associated with venous stasis, hypertension, and obstructive sleep apnea, all risk factors for thrombotic complications. Smoking and mobility status also contribute to the risk of thromboembolism. Procedure-related factors that increase risk include prolonged operative time, procedure type, and postoperative complications. Recommendations include using a risk-assessment tool, emphasizing pulmonary toilet, ambulation, minimization of opioids, low molecular weight heparin use, and mechanical compression devices or compression stockings. A vena cava filter may be considered in those with multiple risk factors. Patients with a body mass index greater than 60 are usually discharged home on low molecular weight heparin for 2 weeks. Patients with prothrombotic conditions may need a longer course of chemoprophylaxis, possibly with direct oral anticoagulants. Coordinating care with a hematologist may be necessary.[26][27]

Dumping syndrome is a common complication following bariatric surgery, particularly after procedures like RYGB and LSG.[28] This issue occurs when food, especially high-sugar or high-fat meals, passes too quickly from the stomach into the small intestine, overwhelming the digestive system. This leads to nausea, abdominal cramps, diarrhea, dizziness, and sweating. Early dumping syndrome occurs within 30 minutes of eating and is typically caused by rapid gastric emptying, while late dumping syndrome happens 1 to 3 hours after eating, usually due to the release of insulin in response to high sugar levels in the small intestine. Management includes dietary modifications (such as smaller, more frequent meals and avoiding simple sugars), and in severe cases, medications like octreotide may be used.

Bariatric surgery increases the risk of nutritional deficiencies. The greater curvature of the stomach contains a large concentration of parietal cells that secrete intrinsic factors and hydrochloric acid. Intrinsic factors facilitate the absorption of vitamin B12. A deficiency of vitamin B12 can lead to megaloblastic anemia and other hematological conditions affecting all marrow cell lines, causing glossitis,  demyelination predominantly involving the posterior and lateral columns of the spinal cord, resulting in cognitive changes, and peripheral neuropathy. Stomach acid facilitates both the absorption of iron and calcium. Iron is reduced to ferrous by acid secreted in the stomach and absorbed in the duodenum. Decreased acid secretion following bariatric surgery predisposes patients to iron-deficiency anemia. Vitamin B1 deficiency after bariatric surgery can present as Wernicke encephalopathy, Korsakoff psychosis, or Beri-Beri.[29]

Recently, there has been an increasing recognition of trace element deficiency after bariatric surgery. Selenium levels are reported to reach a nadir 1 year after bariatric surgery. Selenium deficiency can present as muscle weakness, cardiomyopathy, skin eruptions, and pedal edema.[30] Supplementation of 100 micrograms daily is protective. Copper deficiency has also been reported after bariatric surgery and can be a cause of microcytic anemia, which is unresponsive to iron therapy.[31] Supplementation with multivitamins, including calcium and iron, is very important following bariatric surgery. Without supplementation, symptoms of deficiencies can manifest as soon as 3 months following surgery, particularly notable in those who had subclinical deficiencies preoperatively.[32][33] 

Increased Risks Associated with Bariatric Surgery

Bariatric surgery, like all major surgical procedures, carries an increased risk of infection, especially due to the nature of the operations involved, such as gastrointestinal anastomoses and significant manipulation of abdominal tissues. Obesity is a risk factor for infection, as excess adipose tissue can impair immune function and circulation, delaying wound healing. Additionally, comorbid conditions such as diabetes and metabolic syndrome, commonly seen in bariatric individuals, further elevate the infection risk. Surgical site infections, pneumonia, and urinary tract infections are among the most common, necessitating vigilant postoperative monitoring and sometimes prophylactic antibiotics.

Bariatric surgery carries inherent risks due to the complexity of the procedures, the patient’s comorbidities, and the general health status. Obese individuals are at higher risk for complications such as deep vein thrombosis, pulmonary embolism, and respiratory issues due to poor lung function and reduced mobility. Cardiovascular stress is another concern, as obesity can strain the heart, and anesthesia management can be more challenging. The larger abdominal cavity and increased tissue fat make laparoscopic procedures more technically difficult, raising the likelihood of complications such as organ injury or bleeding during surgery.

Reoperation risk is heightened after bariatric surgery due to complications like anastomotic leaks, strictures, hernias, and internal bleeding. These complications may occur immediately postoperatively or even years later. Procedures like RYGB and LSG have a higher reoperation risk than purely restrictive procedures, as malabsorptive components create additional points of failure. Internal hernias and marginal ulcers are common causes for reoperation, requiring either endoscopic intervention or surgical correction. Weight regain, or complications like leaks from staple lines may also necessitate reoperation or conversion to another surgical approach.

Psychosocial Concerns with Bariatric Surgery

After bariatric surgery, patients face significant psychological and social challenges that can affect their long-term success. The profound body changes resulting from surgery can lead to issues with body image, self-esteem, and emotional well-being. Patients may experience depression, anxiety, or eating disorders as they adjust to their new appearance and lifestyle. For individuals with a history of mental health conditions, including eating disorders, these challenges can be even more pronounced, potentially impacting surgical outcomes. The emotional and psychological strain of adjusting to a new body and identity often requires ongoing counseling and support.

Socially, patients often experience shifts in their relationships and self-perception after significant weight loss. Changes in how others treat them and how they perceive themselves can result in shifts in social dynamics and personal identity. This can lead to challenges in adjusting to a new social role, affecting self-esteem and confidence. Additionally, some patients may experience isolation or difficulties with their new sense of self, requiring continued emotional and social support.

Weight gain and recidivism also present significant concerns after bariatric surgery. While patients typically experience substantial weight loss in the first year, long-term weight regain is common, especially among those who fail to adhere to critical lifestyle changes, such as dietary modifications and regular exercise. Psychological factors, poor eating habits, and lack of exercise often contribute to this regain. In some cases, changes in gastric anatomy, such as sleeve dilation or stretching of the gastric pouch, can also play a role in recidivism. For instance, weight regain after LSG often occurs due to excessive sugar consumption without causing gastric pouch dilation.

Over time, the sleeve may also dilate, reducing its restrictive effect. These issues can be addressed by converting to a RYGB, resulting in further weight loss.[34] Another potential complication is stricture of the gastrojejunostomy anastomosis, typically seen in the early stages following an RYGB. In later years, dilation of this anastomosis may occur, and both issues can be managed with endoscopic intervention.[35] Bariatric surgery remains one of the most effective treatments for obesity, but patients must remain committed to maintaining the lifestyle changes necessary for sustaining long-term weight loss. For some, additional interventions or procedures may be required to address complications or weight regain.

Clinical Significance

Though generally uncommon, bariatric surgery complications can have significant clinical implications, underscoring the need for comprehensive, multidisciplinary care. Complications like anastomotic leaks, bleeding, internal hernias, malnutrition, and gastrointestinal issues can result in severe, sometimes life-threatening consequences. These complications often require prompt diagnosis, tailored treatment plans, and ongoing management, making it critical for patients to receive care from diverse healthcare professionals, each offering expertise in different areas.

The clinical significance of these complications is multifaceted. For example, anastomotic leaks or internal hernias can lead to peritonitis, sepsis, and organ failure if not managed quickly and effectively. Nutritional deficiencies, such as vitamin B12, iron, and calcium deficiencies, can result in long-term health problems, including anemia, osteopenia, and neurological complications. Psychological complications, including depression and anxiety, may arise or worsen as patients adjust to dramatic changes in their bodies and lifestyles, further complicating the recovery process. Given the broad spectrum of potential issues—ranging from metabolic and nutritional concerns to psychological and surgical complications—bariatric surgery requires input from a wide array of specialists.

Multidisciplinary care is essential for optimizing patient outcomes and addressing the challenges that arise postoperatively. A team of surgeons, dietitians, psychologists, endocrinologists, and physical therapists ensures that all aspects of a patient's health are monitored and managed. This comprehensive, team-based approach significantly improves bariatric surgery patients' long-term success and health by addressing the physical and psychological aspects of recovery and lifestyle change.

Other Issues

Advances in targeted therapy have provided additional options for those experiencing obesity, and insurance approval for bariatric surgery is less restrictive than previously, with the increasing recognition of the long-term impact. However, access to effective medications, including GLP-1 and GIP agonists, remains cost-prohibitive. The obesity epidemic impacts a large proportion of the American population, including children. In 2023, the American Academy of Pediatrics introduced new guidelines that propose surgery for adolescents using the same body mass index criteria as in adults. Morbid obesity in adolescents shortens life expectancy by 10 to 15 years, and addressing obesity earlier has been shown to reverse comorbidities better than in older individuals.[36] Genetic screening for monogenic obesity is available, and medications exist that target the cause of those persons diagnosed with a specific pathogenic genetic variant, including medication targeting the melanocortin receptor and those with leptin, proopiomelanocortin, and proprotein subtilisin kexin type 1 deficiency.[37] 

Enhancing Healthcare Team Outcomes

Effective management of bariatric surgery complications requires strong collaboration and interprofessional communication among advanced clinicians, nurses, pharmacists, and other healthcare professionals. Clinicians, particularly bariatric surgeons, lead the team by diagnosing and addressing surgical complications such as anastomotic leaks or internal hernias, while advanced clinicians, including nurse practitioners and physician assistants, provide continuous patient assessments and support during postoperative care. Nurses are crucial in monitoring vital signs, managing pain, and detecting early signs of complications such as infection or gastrointestinal distress. Pharmacists contribute by ensuring appropriate medication management, particularly pain control, antibiotics, and nutritional supplements, to prevent deficiencies that can arise post-surgery.

Interprofessional communication is key to enhancing patient outcomes and ensuring the team is aligned regarding strategies. Effective care coordination between these roles ensures that nutritional needs are met, psychological support is available, and any complications are addressed promptly. For instance, the nutritionist works with the surgical team to monitor the patient's diet and nutritional status. At the same time, the psychiatrist or psychologist may address emotional challenges or eating disorders that impact recovery. Coordinated efforts help mitigate risks, improve patient safety, and improve outcomes, as the team can provide comprehensive care tailored to each patient’s needs. This holistic, patient-centered approach fosters a supportive environment for patients and ensures timely interventions, ultimately improving team performance and optimizing the success of bariatric surgery.

Nursing, Allied Health, and Interprofessional Team Interventions

Interprofessional collaboration is important for optimal results following bariatric surgery. An accurate assessment and counseling to focus on eating habits and glycemic control is crucial before and following bariatric surgery. Nutritional expert-led support groups increase long-term weight loss and help optimize nutrition. Involving a diverse interdisciplinary team in bariatric programs improves communication, and identification of issues, and allows more timely access to clinical care. Treatment teams optimize outcomes and improve recidivism in a condition that can result in tremendous morbidity and mortality.[38][39] 

Nursing, Allied Health, and Interprofessional Team Monitoring

Nutritional parameters should be monitored regularly after bariatric surgery, including B vitamins, iron and trace elements. General labwork should be followed annually, including liver function tests, complete blood count, basic metabolic panel, and lipid panel.[40]