The purpose of this review is to evaluate the incidence and management of internal hernias (with or without SBO) after LGBP.
Laparoscopic Roux-en-Y gastric bypass (LGBP) has been shown to be an effective treatment for morbid obesity, both in terms of weight loss and improvement in multiple comorbidities. While the laparoscopic approach offers many advantages to the patient in terms of fewer wound complications, decreased length of hospital stay, and decreased postoperative pain, certain complications of this operation continue to pose difficult clinical problems as the number of procedures performed increases. One such complication is internal hernia through one of the mesenteric defects, which can result in small bowel obstruction, ischemia, or infarction and often requires reoperation.
An internal hernia is defined as a protrusion of intestine through a defect within the peritoneal cavity, as opposed to an external (or incisional) hernia that protrudes through all layers of the abdominal wall. Internal hernias almost always occur through iatrogenic defects created surgically.
Incisional hernias occur at a higher incidence after open gastric bypass (GBP) at a rate of about 20 percent. LGBP has a lower rate of incisional hernias. A recent study by Rosenthal, et al., showed a 0.2-percent rate of port site hernias in 849 patients using blunt-tip trocars at 3,744 port sites. Internal hernias, on the other hand, occur more frequently in LGBP than in the open procedure. This is a significant clinical problem, since internal hernia is the most common cause of small bowel obstruction (SBO) after LGBP. Retrospective reviews have found the incidence of SBO after LGBP to be between 1.8 and 9.7 percent. The incidence of internal hernia after LGBP is between 0.2 and 8.6 percent based on multiple studies.
This incidence is higher than that seen with open GBP, and this is presumably due to decreased adhesion formation after laparoscopic surgery compared to open surgery. The creation of potential space as a result of weight loss may also be a contributing factor in the etiology of internal hernias, which often present in a delayed fashion. In addition, the particular case of pregnancy— with the mass effect of an enlarging uterus—may predispose to this condition, as there have been three case reports in the literature of internal hernia during pregnancy, one of which resulted in intestinal ischemia and fetal demise. Due to the increasing scope of this problem and its potentially devastating consequences, surgeons should have a high clinical suspicion for internal hernia after LGBP.
An internal hernia can potentially occur through either two or three defects, depending on whether a retrocolic or antecolic technique is used for the Roux limb. Petersen’s defect is defined as the space between the Roux limb and the transverse mesocolon. A defect is also present between the biliopancreatic and Roux limbs at the jejunojejunostomy. If a retrocolic approach is used, a third defect in the transverse mesocolon is created. This is the most common site of internal hernia in most reports, which has prompted many surgeons to adopt an antecolic technique in order to eliminate this defect. Higa’s study of 2,000 patients showed an internal hernia distribution of 67 percent mesocolic, 21 percent jejunal, and 7.5 percent Petersen. However, some centers experience a higher rate of hernia in the jejunal or Petersen’s defects, despite the use of a retrocolic approach.
Patients with internal hernia most commonly present with abdominal pain, and may also have symptoms of small bowel obstruction. The time of presentation varies greatly and may occur within one week of the initial operation or up to three years postoperatively. However, the majority of cases occur between 6 and 24 months postoperative. Radiographic diagnosis of internal hernia presents a challenge since the characteristic findings on computed tomography (CT) scan are often missed.
Features suggestive of an internal hernia include small bowel loops in the upper quadrants; evidence of small bowel mesentery crossing the transverse mesocolon; presence of the jejunojejunostomy superior to the transverse colon; signs of small bowel obstruction; or twisting, swirling, crowding, stretching, or engorgement of the main mesenteric trunk and according to one study, the sensitivity and specificity of CT is 63 percent and 76 percent, respectively.
Another study showed that although the diagnosis was only made prospectively by CT scan in 64 percent of cases, a retrospective review of the images showed that diagnostic abnormalities were present in 97 percent of cases. A report of five cases of internal hernia by Onopchenko found that only one was diagnosed preoperatively by radiological reading, even though all five had findings suggestive of internal hernia to the bariatric surgeon. These findings emphasize the need for communication with the radiologist, careful attention to patient history, and high clinical suspicion for internal hernias. In rare cases, closed loop obstruction and extensive bowel ischemia and infarction can occur. This dreaded complication underscores the necessity of making a rapid diagnosis. If the patient has significant symptoms but radiologic studies are negative, a diagnostic laparoscopy is warranted to rule out internal hernia.
PREVENTION AND TREATMENT
Given the prevalence of internal hernias and the increasing popularity of bariatric surgery, it is important to prevent or minimize this complication at the time of the initial operation. Although there have been no randomized, controlled trials comparing different techniques of LGBP, some authors have anecdotally reported lower rates of internal hernia after modifying their technique from a retrocolic to antecolic approach. Champion and Williams reported a significant decrease in small bowel obstruction after changing to an antecolic position, and Felsher and colleagues found no internal hernias in their study after adopting the antecolic approach.
However, other studies support careful defect closure as the most important factor in reducing hernia rates. Dresel and colleagues report no internal hernias after modifying their technique to include closure of Petersen’s defect. Carmody and colleagues report a decreased hernia incidence when closing all defects, even with a retrocolic approach. DeMaria’s study reports anecdotal improvement after closing mesenteric defects in two layers, on the medial and lateral aspects of the defect.
The majority of internal hernias can be successfully treated laparoscopically, with reduction and defect closure. The laparoscopic approach is usually successful; however, because of the lack of adhesion formation after laparoscopy, Capella, et al., suggest laparotomy for patients who experience a second episode of bowel obstruction due to recurrent internal hernia after laparoscopic repair. The greater adhesion formation after laparotomy may help prevent future internal hernia formation.
One of the benefits of laparoscopy, decreased adhesion formation, is likely also responsible for the increasing prevalence of internal hernia as a complication following laparoscopic gastric bypass. Although it has not been borne out in randomized clinical trials, anecdotal evidence and expert opinion suggest that Roux limb position and mesenteric defect closure at the time of initial operation are important factors in ultimate rates of hernia formation. Careful attention must be paid to individual surgical techniques in order to prevent this potentially devastating complication. The benefits of LGBP are maximized when there is a low incidence of postoperative hernias and resultant obstruction.
The association between GERD and obesity has generated great interest, because obesity has been indicated as a potential risk factor for reflux disease. A directly dependent relationship has been reported because an increase in body mass index has mirrored an increase in the risk of GERD. The incidence of reflux in the obese population has been cited as high as 61%. The pathophysiologic mechanism underlying the link between obesity and GERD has not been fully elucidated and seems to be multifaceted. As the number of obese patients is increasing, so is the volume and variety of bariatric procedures. The effect of bariatric surgery on preexisting GERD or newly developed GERD differs by procedure.
GERD AFTER ROUX-EN-Y GASTRIC BYPASS
Roux-en-Y gastric bypass (RYGB) has been used as a standalone reflux procedure. Mechanisms of the antireflux effect of RYGB include diverting bile from the Roux limb, promoting weight loss, lowering acid production in the gastric pouch, rapid pouch emptying, and decreasing abdominal pressure over the LES. Several studies have examined the relationship between GERD and RYGB. Studies have also analyzed symptomatic relief by using questionnaires before and after the procedure. One study has examined further the incidence of esophagitis postoperatively on endoscopy. Merrouche and colleagues showed a 6% incidence of esophagitis on endoscopy after RYGB; however, the preoperative incidence was not mentioned.
Pallati and colleagues also examined the GERD symptoms after several bariatric procedures by using the Bariatric Outcomes Longitudinal Database. GERD score improvement was highest in the RYGB group; 56.5% of patients showed improvement of symptoms. The study concluded that RYGB was superior to all other procedures in improving GERD. The proposed but unproven mechanisms included a greater weight loss and a decrease in the amount of gastric juice in the proximal pouch. The study, however, did not show any objective measures of GERD improvement. Another study by Frezza and colleagues showed a significant decrease in GERD-related symptoms over the 3-year study after laparoscopic RYGB, with decrease in reported heartburn from 87% to 22% (P<.001). The authors proposed that, in addition to volume reduction and rapid egress, the mechanism of how this procedure affects symptoms of GERD is through weight loss and elimination of acid production in the gastric pouch. The gastric pouch lacks parietal cells; thus, there is minimal to no acid production and also, owing to its small size, it minimizes any reservoir capacity to promote regurgitation.
Varban and colleagues examined the utilization of acid-reducing medications (proton pump inhibitor and H2-blockers) at 1 year after various bariatric procedures. The groups reported that at 1 year after RYGB, 56.2% of patients would discontinue an acid-reducing medication that they had been using at baseline. Interestingly, the group also showed that 19.2% of patients would also start a new acid-reducing medication after RYGB. Given the number of studies that have reported improvement in GERD symptoms after RYGB, this procedure is now widely accepted as the procedure of choice for treatment of GERD in the morbidly obese patient. Although no increased risk is conferred to patients with a body mass index of 35 kg/m2 or higher who undergo fundoplication for GERD the recommendation and practice of many surgeons is to perform a laparoscopic gastric bypass in lieu of fundoplication owing to its favorable effect on other comorbid conditions. In addition, advocates of the RYGB are promoting a conversion to an RYGB instead of a redo fundoplication.
In a recent study, Stefanidis and colleagues followed 25 patients who had previous failed fundoplication, which was taken down and converted to an RYGB. Patients were followed with the Gastrointestinal Quality of Life Index and the Gastrointestinal Symptoms Rating Sale. The revision surgery led to resolution of GERD symptoms for a majority of the patients. The authors concluded that an RYGB after a failed fundoplication has excellent symptomatic control of symptoms and excellent quality of life. However, owing to the technical challenges of the procedure and the potential for high morbidity, it should only be performed by experienced surgeons.
GERD AFTER SLEEVE GASTRECTOMY
Sleeve gastrectomy (SG), which was originally described as a first stage of the biliopancreatic diversion, is a relatively new treatment alternative for morbid obesity. It has become popular owing to its technical simplicity and its proven weight loss outcomes. Although it has many positive effects on obesity and obesity-related comorbidities, the association between GERD and SG remains controversial. Although some studies have reported improvement in GERD symptoms after SG, the majority of studies have reported an increase in GERD symptoms. The International Sleeve Gastrectomy Expert Panel reported a postoperative rate of GERD symptoms after SG in up to 31%; however, others cited increased GERD prevalence after surgery between 2.1% and 34.9%.
Studies Showing an INCREASE: Several studies have shown an increase of GERD after SG at various time points. The comparison between different studies is difficult owing to variations in the definition of GERD. Although some have utilized the use of proton pump inhibitors as a diagnostic tool, others have used the definition of typical heartburn and/or acid regurgitation occurring at least once per week. Few studies used objective data to define reflux.
Tai and colleagues examined symptoms of GERD and erosive esophagitis at 1 year after laparoscopic sleeve gastrectomy (LSG). The groups concluded that there was a significant increase in the prevalence of GERD symptoms and erosive esophagitis (P<.001), in addition to a significant increase in the prevalence of hiatal hernias (P<.001), which was higher in patients who presented with erosive esophagitis after LSG. Others have shown a similar increase of GERD at 1 year. Himpens and colleagues compared adjustable gastric banding (AGB) and SG at 1 and 3 years after procedures. GERD seemed de novo after 1 year in 8.8% and 21.8% of patients with AGB and SG, respectively. At 3 years, however, rates changed to 20.5% and 3.1% in the ABG and SG groups. Another study followed patients for more than 6 years and reported 23% to 26% of patients reporting frequent episodes of GERD. Various mechanisms have been postulated to cause symptoms of GERD after LSG. As SG alters the gastroesophageal anatomy, it has been hypothesized that the anatomic abnormalities created contribute to the development of GERD in patients.
Lazoura and colleagues showed that the final shape of the sleeve can influence the development of GERD. The group showed that patients with tubular pattern and inferior pouch (preservation of the antrum) did better in terms of regurgitation and vomiting compared with a tubular sleeve with a superior pouch. Others have also suggested the importance of antral preservation to avoid GERD development. An increase in acid production capacity can cause reflux in the case of an overly dilated sleeve, whereas impaired esophageal acid clearance can lead to reflux in a smaller sleeve. Formation of a neofundus can in an effort to avoid fistulas may also lead to development of GERD. Daes and colleagues further concentrated on describing and standardizing the procedure to reduce GERD symptoms. The authors identified 4 technical errors that led to development of GERD after the procedure: relative narrowing at the junction of the vertical and horizontal parts of the sleeve, dilation of the fundus, twisting of the sleeve, and persistence of hiatal hernia or a patulous cardia. By ensuring careful attention to surgical technique and performing a concomitant hiatal hernia repair in all patients, they reduced the rate of postoperative GERD to only 1.5%. The group concluded that hiatal hernia is the most important predisposing factor.
Studies Showing REDUCTION: Several studies have reported either decreased or no association between GERD and LSG. Interestingly, in some of these studies, GERD improvement has been reported as a secondary outcome. Rawlins and colleagues reported an improvement of symptoms in 53% of patients, but de novo GERD in 16% of patients. A multicenter prospective database review examined GERD in all 3 major bariatric procedures and reported improvement in all. The authors used medication use to define GERD. A small portion of patients reported worsening GERD, which was highest in the SG group. Sharma and colleagues also reported an improvement of GERD as assessed by symptom questionnaires, as well as improvement in grade of esophagitis on endoscopy. The possible mechanisms for improvement of GERD postoperatively are faster gastric emptying, reduction in gastric reservoir function, gastrointestinal hormonal modifications, decrease in acid secretions, and decrease in weight. Daes and colleagues reported a decrease in incidence of GERD by using a standardized operative technique and concomitant repair of hiatal hernia.
Owing to conflicting reports about the association between GERD and LSG, this procedure is controversial in patients with preexisting GERD. If LSG is considered in this population, hiatal hernia repair and meticulous technique are essential. We would like to emphasize the importance of preoperative testing to define the anatomy and evaluate preexisting GERD, esophagitis, Barrett’s esophagus, or the presence of hiatal hernia.
Obesity is one of the most significant health problems worldwide, and the prevalence has been increasing over the past decade. Despite improvement in the performance of bariatric surgery, complications are not uncommon. These complications vary according to baseline patient characteristics, the duration of time since the operation, and the type of bariatric surgery performed. Endoscopy is the cornerstone in the diagnosis of postoperative complications after bariatric surgery, and may even be performed in the early postoperative course. With an increasing number of patients being referred for endoscopic evaluation following bariatric surgery, it is essential to develop an understanding of the anatomic changes for optimal assessment and appropriate treatment of these patients.
Early and late dumping syndrome occurs not uncommonly in patients who have undergone gastric bypass surgery when large quantities of simple carbohydrates are ingested. Early dumping typically occurs within 15 minutes of ingestion and has been attributed to rapid fluid shifts from the plasma into the bowel from hyperosmolality of the food. Late dumping occurs hours after eating and results from hyperglycemia and the subsequent insulin response leading to hypoglycemia. When hypoglycemia is severe, treatment with a low carbohydrate diet and an alphaglucosidase inhibitor may be effective. Furthermore, restoration of gastric restriction using an endoscopic approach to reduce the aperture of the GJA has also demonstrated to be effective in management of this condition.
The initial management of dumping syndrome is dietary modifications. Recommendations include consuming smaller meals by dividing daily calorie intake into six meals and delaying liquids at least 30 min after meals Rapidly absorbable simple carbohydrates should also be avoided. Adjuncts to diet modification include pectin and guar gum, which slow down gastric emptying by increasing food viscosity. Acarbose, which interferes with carbohydrate absorption in the small intestines, has also proven to relieve symptoms in small studies. After dietary modifications, medications such as somatostatin analogs (e.g., octreotide) alleviate symptoms by delaying gastric emptying and small bowel transit time, as well as inhibiting gastric hormones and insulin secretion. Multiple studies have evaluated both short- and longterm somatostatin therapies, with results showing sustained symptom control in patients refractory to dietary modifications. In severe cases refractory to medical management, surgical interventions, such as narrowing of the anastomosis, conversion of the prior bariatric surgery, and using jejunostomy parenteral feeding, may help. Follow-up with gastrointestinal specialists and the patient’s bariatric surgeon is strongly recommended if dumping syndrome is suspected.
An important metabolic complication which is attracting increasing interest is postprandial hyperinsulinemic hypoglycemia (PHH), characterized by hypoglycemic symptoms developing 1–3 h after a meal accompanied by a low blood glucose level. This condition should be distinguished from early dumping syndrome where symptoms develop within minutes to 1 h after a meal of caloric dense food, caused by the rapid and unregulated emptying of food into the jejunum, which induces rapid fluid entry into the small bowel. Early dumping often occurs early in the postoperative period, most commonly after Roux-en-Y gastric bypass, whereas PHH may develop months to years after surgery.
Symptoms related to post-PHH usually develop late after surgery in contrast to early dumping. Symptoms are wide ranging, but are usually related to Whipple’s triad: symptomatic hypoglycemia, a low plasma glucose level, and resolution of symptoms after the administration of glucose. Symptoms of hypoglycemia may include anxiety, sweating, tremors, palpitations, confusion, weakness, lightheadedness, dizziness, blurred vision, disorientation, and possibly loss of consciousness.
Because of variability in degree of symptoms and the absence of a clear pathophysiology, management of this condition can be challenging. Fortunately, a significant percentage of patients with milder forms of the condition can be managed with dietary modifications consisting of frequent small meals with a low glycemic index. This requires supervision by a dietitian and long-term patient compliance. Additional benefit has been obtained by the addition of acarbose, an α glucosidase inhibitor in doses 100–300 mg. Successful management has been also reported in case reports or small case series with diazoxide, calcium channel blockers, and somatostatin analogues. The role of GLP-1 in the pathogenesis of this condition is supported by the observation that infusions of GLP-1 antagonists corrected hypoglycemia in these patients. These agents are investigational at present, but provide opportunity for additional future treatment approaches. For patients with persistent symptoms despite medical treatment, reversal of the bariatric procedure should be considered. Partial pancreatectomy, although used in the past, is now not recommended because of the significant morbidity and poor long-term symptom control. Postprandial hyperinsulinemic hypoglycemia is an important, potentially dangerous late complication of metabolic surgery. Successful diagnosis and management of this condition requires multidisciplinary specialty resources and essential long-term follow-up capabilities.
Bariatric procedures differ in their ability to ameliorate T2DM, with intestinal bypass procedures generally associated with greater glycemic control and remission rates than purely restrictive procedures. There has been until now a paucity of data from RCTs comparing the efficacy of various bariatric procedures to treat diabetes. The recently published RCT by Schauer et al. also indicates superior efficacy of RYGB over sleeve gastrectomy in the treatment of diabetes in obese individuals. On the other hand, BPD produced greater remission of diabetes in morbidly obese patients compared to RYGB (95 % versus 75 %) in the RCT reported by Mingrone et al.
Sleeve Gastrectomy as Metabolic Surgery
Karamanakos et al. showed that LSG suppressed fasting and postprandial ghrelin levels and attributed this decrease in ghrelin to improved postoperative satiety and greater weight loss at 1year compared to LRYGB. The LRYGB group in this study had an initial decrease in ghrelin levels after surgery, but these levels returned to normal levels within 3 months. Lee et al. studied the treatment of patients with a low body mass index and type 2 diabetes mellitus between the two groups. LRYGB is reportedly more effective than LSG; they conclude that both procedures have strong hindgut effects after surgery, but LRYGB has a significant duodenal exclusion effect on cholecystokinin. The LSG group had lower acylated ghrelin and des-acylated ghrelin levels but greater concentrations of resistin than the LRYGB group. In addition to evaluations of ghrelin, there are now several small studies demonstrating that gastric emptying is increased after sleeve gastrectomy. The loss of a large reservoir in the gastric fundus and body and preservation of the antral pump provide a reasonable explanation for this finding. A secondary effect of earlier distal bowel stimulation with nutrients after meals due to increased gastric emptying time may be similar to the effects seen after gastric bypass.
Several mechanistic studies have demonstrated early and exaggerated postprandial peak levels of Peptide YY3–36 and GLP-1 after LSG. GLP-1 is an incretin that stimulates insulin production and releases from pancreatic islet cells, and the increased PYY3–36 results in satiety and reduced food intake. Karamanakos et al. have independently shown that the sleeve gastrectomy does have the effect of increasing the transit time of chyme despite an intact pylorus as measured by increased postprandial PYY levels.
Peterli et al. performed a randomized prospective trial with 13 LRYGB and 14 LSG patients to investigate the potential mechanism of LSG focusing on foregut and hindgut mechanisms. They found marked improvement in glucose homeostasis 1 week after surgery in both groups. This improvement was associated with early, exaggerated increases in GLP-1 secretion at 1 week, 3 months, and 1 year postoperatively in both groups. In addition to changes in GLP-1, PYY3–36 increased significantly and ghrelin was suppressed in both groups. It is unclear whether PYY3–36 has a direct effect on glucose homeostasis or if its effects are exhibited via appetite reduction and concomitant weight loss. Preoperatively, some patients had a blunted PYY3–36 and GLP-1 response suggesting some “resistance” to these gut hormones in obese patients. These findings suggest that the LSG should not be viewed merely as a restrictive procedure but also as a procedure that has neurohormonal and incretin effects.
Gastric Bypass versus Laparoscopic Sleeve Gastrectomy
Ramon et al. compared the effects of LRYGB and LSG on glucose metabolism and levels of gastrointestinal hormones such as ghrelin, leptin, GLP-1, peptide YY (PYY), and pancreatic polypeptide (PP) in morbid obese patients. This prospective, randomized study confirmed that the postprandial response of ghrelin, GLP-1, and PYY was maintained in patients undergoing LSG for 12 months after surgery and was similar to the LRYGB group results. A prospective, randomized study by Woelnerhanssen et al. compared the 1-year results of LRYGB and LSG for weight loss, metabolic control, and fasting adipokine levels. The authors confirmed a close association of specific adipokines with obesity and with the changes observed with weight loss after two different bariatric surgical procedures. The concentrations of circulating leptin levels decreased by almost 50 % as early as 1 week postoperatively and continued to decrease until 12 months postoperatively and adiponectin increased progressively. No differences were found between the LRYGB and LSG groups regarding adipokine changes.
How to choice a procedure?
The choice of procedure is an important determinant of outcome with a decreasing gradient of efficacy predicted from BPD, RYGB to SG and then
LAGB. Other factors that have been positively correlated with diabetes remission are percentage of excess weight loss (% EWL), younger age, lower preop HbA1c, and shorter duration of diabetes (less than 5 years). Severity of diabetes, as judged by preop treatment modality, has also been noted to be a significant factor.
Schauer et al. have reported in their series of 191 obese diabetic patients (the majority of whom were on oral agents or insulin) a diabetes remission rate of 97 % in diet-controlled, 87 % in oral agent treated, and 62 % in insulin-treated subjects. This was also confirmed by a recent retrospective analysis of 505 morbidly obese diabetic patients who underwent RYGB. In this study, a more recent diagnosis of T2DM and the absence of preoperative insulin therapy were significant predictors of remission, independent of the percentage of EWL.
Dixon et al. have recently identified diabetes duration < 4 years, BMI > 35 kg/m2, and fasting c-peptide concentration > 2.9 ng/ mL as three clinically useful cutoffs and independent preoperative predictors of remission after analyzing the outcomes of 154 ethnic Chinese subjects after gastric bypass. C-peptide > 3 ng/mL has also previously been shown to be an important predictor of diabetes resolution after sleeve gastrectomy in non-morbidly obese diabetic subjects by Lee et al.
Sleeve gastrectomy (SG), or longitudinal gastric resection, consists in a resection of the greater curvature of the stomach. In bariatric surgery, it was introduced by Hess in 1988 and by Marceau in 1990 as a component of the biliopancreatic diversion with duodenal switch (BPD/DS). Resecting the greater curvature of the stomach was aimed at reducing the risk of ulcer at the level of the duodeno-ileal anastomosis of the BPD/ DS. In fact, for those authors, the amount of stomach removed was estimated to be roughly 60% and the restriction was moderate. With a view to reducing the mortality associated with laparoscopic BPS/DS in super-super-obese patients, Regan et al. described a 60-French (F) bougiecalibrated isolated sleeve gastrectomy (ISG) as a first step in a two-stage program of laparoscopic BPD/DS in 2000. Since then, primary ISG has gained popularity in a staged surgery program for high-risk patients. Although medium- to long-term results are not known, and some technical details are still being discussed, the good short-term results obtained regarding weight loss, as well as co-morbidity and the acceptable rate of complications, have broadened the indications for primary ISG and assured its place in the armamentarium of bariatric surgical procedures. In June 2007, a position statement on SG as a bariatric procedure was endorsed by the ASMBS, and in October 2007 the First International Consensus Summit for Sleeve Gastrectomy was held in New York City.
As expected, the operation is restrictive (satiety occurs very quickly). Indeed, with the current calibration of the sleeve, its volume is less than 10% of the entire stomach and its distensibility is 10 times less than that of the resected stomach and fundus. Nevertheless, after 6 months, patients can cope with a mug-sized meal (200 ml) of solid food. Even if the size of the meal is small, the volume of the remaining stomach is larger by far than after purely restrictive procedures (gastric banding, vertical banded gastroplasty). Melissas et al. demonstrated an accelerated gastric emptying of solid food into the duodenum and the intestine at 6 and 24 months, and this could explain some enterohormonal changes . In addition to these mechanical effects, SG has hormonal effects. This operation is “anorexigenic”; the patients feel little hunger and have only a mild interest in eating. Most of them could skip a meal each day for at least 1 year after surgery. The fundus is known to be the major source of ghrelin, an orexigenic hormone. It has been proved that the level of ghrelin is dramatically reduced after the currently performed SG with the entire fundus resected, and to a higher degree than with gastric banding or gastric bypass. Other hormonal changes have been noted, such as a rise in the level of fasting PYY or GLP1, a hormone that induces also a feeling of satiety. This latter point has yet to be assessed in human beings. These incretin modifications could play a role in the remarkable short-term effects observed on diabetes. Thus it appears that LSG is a multifactorial procedure with a mild restrictive aspect and a complex neurohormonal aspect.
Over the past decade, following the publication of several long-term outcome studies that showed a significant improvement in cardiovascular risk and mortality after bariatric surgery, the number of bariatric procedures being carried out annually in the UK has grown exponentially. Surgery remains the only way to produce significant, sustainable weight loss and resolution of comorbidities. Nevertheless, relatively few surgeons have developed an interest in this field. Most bariatric surgery is now performed in centres staffed by surgeons with a bariatric interest, usually as part of a multidisciplinary team.
The commonest weight loss procedures performed around the world at present are the gastric band, the gastric bypass and the sleeve gastrectomy. In very obese patients, an alternative operation is the duodenal switch, while the new ileal transposition procedure represents one of the few purely metabolic operations designed specifically for the treatment of type II diabetes. Older operations such as vertical banded gastroplasty and jejuno-ileal bypass are now obsolete, although patients who have undergone such procedures in the distant past may still present to hospital with complications. The main endoscopic option at present is insertion of a gastric balloon, with newer procedures like the endoscopic duodenojejunal barrier and gastric plication on the horizon. Implantable neuroregulatory devices (gastric ‘pacemakers’) represent a new direction for surgical weight control by harnessing neural feedback signals to help control eating.
It should be within the capability of any abdominal surgeon to manage the general complications of bariatric surgery, which include pulmonary atelectasis/pneumonia, intra-abdominal bleeding, anastomotic or staple-line leak with or without abscess formation, deep vein thrombosis (DVT)/pulmonary embolus and superficial wound infections. Patients may be expected to present with malaise, pallor, features of sepsis or obvious wound problems. However, clinical features may be difficult to recognise owing to body habitus. Abdominal distension, tenderness and guarding may be impossible to determine clinically due to the patient’s obesity. Pallor is non-specific. Fever and leucocytosis may be absent. Wound collections may be very deep. These complications in a bariatric patient should be actively sought with appropriate investigations. In particular, it is vital for life-threatening complications such as bleeding, sepsis and bowel obstruction to be recognised promptly and treated appropriately. A persistent tachycardia may be the only sign heralding significant complications and should always be taken seriously. It is useful to classify complications as ‘early’, ‘medium’ and ‘late’ because, from the receiving clinician’s point of view, the differential diagnosis will differ accordingly.
The risk of complications and mortality in bariatric surgery is associated with certain factors that are common to other patients and procedures, including age above 65 years, the presence of associated diseases (cardiovascular and pulmonary disease, chronic renal failure, liver cirrhosis, etc.), prior abdominal surgery, and the experience of the surgeon and the institution, especially concerning the ability to make an early diagnosis and address complications. The surgical complications observed in the early postoperative period following surgeries performed to treat severe obesity are similar to those associated with other major surgeries of the gastrointestinal tract. However, given the more frequent occurrence of medical comorbidities (such as diabetes, arterial hypertension, and sleep apnea), as well as the difficulty in making an early diagnosis of the complications (due to limitations of the clinical abdominal workup and imaging methods, such as ultrasonography and computed tomography, particularly in highly obese patients with body mass indices >50 kg/m²), these patients require special attention in the early post operative follow-up. Pulmonary thromboembolism, a complication associated with bariatric surgery, also requires greater attention from the medical team given the high mortality rate associated with this condition. Early diagnosis and appropriate treatment of these complications are directly associated with a greater probability of control.