The mechanism of weight loss with laparoscopic adjustable gastric banding: induction of satiety not restriction

New Lessons from the gut: Studies of the role of gut peptides in weight loss and diabetes resolution after gastric bypass and sleeve gastrectomy

It has been known since 2005 that the secretion of several gut hormones changes radically after gastric bypass operations and, although more moderately, after sleeve gastrectomy but not after gastric banding. It has therefore been speculated that increased secretion of particularly GLP-1 and Peptide YY (PYY), which both inhibit appetite and food intake, may be involved in the weight loss effects of surgery and for improvements in glucose tolerance. Experiments involving inhibition of hormone secretion with somatostatin, blockade of their actions with antagonists, or blockade of hormone formation/activation support this notion. However, differences between results of bypass and sleeve operations indicate that distinct mechanisms may also be involved. Although the reductions in ghrelin secretion after sleeve gastrectomy would seem to provide an obvious explanation, experiments with restoration of ghrelin levels pointed towards effects on insulin secretion and glucose tolerance rather than on food intake. It seems clear that changes in GLP-1 secretion are important for insulin secretion after bypass and appear to be responsible for postbariatric hypoglycemia in glucose-tolerant individuals; however, with time the improvements in insulin sensitivity, which in turn are secondary to the weight loss, may be more important. Changes in bile acid metabolism do not seem to be of particular importance in humans.

Banded Versus Non-banded Sleeve Gastrectomy: A Systematic Review and Meta-Analysis

Standard bariatric surgeries include biliopancreatic diversion (BPD), sleeve gastrectomy (SG), Roux-en-Y gastric bypass (RYGB), and adjustable gastric banding (AGB). Laparoscopic sleeve gastrectomy (LSG) is currently favored due to safety, efficacy, and shorter operation time. However, previous literature shows 75.6% weight regain post LSG. Introducing Laparoscopic band sleeve gastrectomy (LBSG) to maintain pouch size is proposed to improve outcomes and reduce weight regain. This study aims to compare the safety and efficacy of LSG vs. LBSG in obese patients. A comprehensive search strategy was executed to identify pertinent literature comparing LBSG and LSG in obese patients. Eligible studies underwent independent screening, and pertinent data were systematically extracted. The analysis employed pooled risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous variables, each accompanied by their respective 95% confidence intervals (CI). Our systematic review and meta-analysis included 15 studies encompassing 3929 patients. Regarding body mass index (BMI), at six, 12, and 24 months, no substantial differences were found between LBSG and LSG groups (p < 0.05). Still, at 36 months, LBSG exhibited significantly lower BMI than LSG (MD = -2.07 [-3.84, -0.29], p = 0.02). Excess Weight Loss (EWL) favored LBSG at 12, 24, and 36 months with MD of 3.30 [0.42, 6.18], 4.13 [1.44, 6.81], and 18.43 [9.44, 27.42], p = 0.02, 0.003, < 0.00001, respectively). Operative time did not significantly differ between the procedures (MD = 2.95, 95%CI [-0.06, 5.95], p = 0.05). Resolution of comorbidities, overall complications, post-operative bleeding, reflux, and early complications did not significantly differ between LBSG and LSG. However, LBSG showed higher post-operative regurgitation than LSG (RR = 2.38, 95%CI [1.25, 4.54], p = 0.008). LBSG showed a substantial decrease in BMI at three-year follow-up and higher EWL at one, two, and three years. However, LBSG procedures exhibited a higher incidence of post-operative regurgitation symptoms than LSG. No substantial differences were noted in BMI at six, 12, or 24 months, EWL at six months, operative time, bleeding, reflux, or overall complications.

Comparison of the mid-term outcomes of banded and non-banded sleeve gastrectomy: safety, food tolerance, and weight regain

BACKGROUND

Long-term weight regain (WR) after sleeve gastrectomy (SG) is a major challenge. Laparoscopic banded SG (BSG) was introduced to overcome pouch dilation and, consequently, WR; however, its mid-and long-term outcomes have not been sufficiently demonstrated.

OBJECTIVE

This study retrospectively evaluated the mid-term weight loss efficacy and morbidity over at least a 4-year follow-up after laparoscopic banded SG using a MiniMizer Gastric Ring® and laparoscopic non-banded SG.

METHOD

The data of 1586 bariatric surgeries were retrospectively evaluated. To ensure homogeneity in our study cohort, propensity score matching (PSM) was performed.

RESULTS

The final cohort comprised 1392 patients: the non-banded SG (n = 1260) and BSG (n = 132) groups. In our matched cohort (SG, n = 655 and BSG, n = 132), WR was noted in 4 (3.0%) and 71 (10.8%) patients in the BSG and SG groups, respectively. Gastric band erosion or slippage was not noted in the BSG cohort. The levels of cholesterol and triglyceride were similar in the two groups. Postoperative glycemic control was significantly reduced in the BSG group.

CONCLUSION

Although the percentage of weight loss achieved in the BSG group was low in the first year postoperatively, the mid-term (sustained) weight loss associated with BSG was superior to that associated with non-banded SG. BSG is a safe procedure with no significant mid-term band-related morbidity; its impact on the resolution of comorbidities is equivalent and perhaps superior to SG.

A review on the beneficial effects of bariatric surgery in the management of obesity

INTRODUCTION

Obesity is a chronic disease with a complex interplay of multiple factors such as genetic, metabolic, behavioral, and environmental factors. The management of obesity includes; lifestyle modification, psychological therapy, pharmacological therapy, and bariatric surgery. To date, bariatric surgery is the most effective treatment for obesity by offering a long-term reduction in weight, remission of obesity-related complications, and improving quality of life. However, bariatric surgery is not equally effective in all patients. Thus, if we can predict who would benefit most, it will improve the risk versus benefit ratio of having surgery.

AREAS COVERED

In this narrative review, we explore the question on who will benefit the most from bariatric surgery by examining the recent evidence in the literature. In addition, we investigate the predisposing predictors of bariatric surgery response. Finally, we offer the best strategies in the clinic to explain the potential benefits of bariatric surgery to patients.

EXPERT OPINION

Bariatric surgery is an effective obesity management approach. Despite its efficacy, considerable variation of individual response exists. Thus, it is important to recognize patients that will benefit most, but at present very few predictors are available which can be clinically useful.

Food cue reactivity in successful laparoscopic gastric banding: A sham-deflation-controlled pilot study

Laparoscopic adjustable gastric banding (LAGB) offers a unique opportunity to examine the underlying neuronal mechanisms of surgically assisted weight loss due to its instant, non-invasive, adjustable nature. Six participants with stable excess weight loss (%EWL ≥ 45) completed 2 days of fMRI scanning 1.5-5 years after LAGB surgery. In a within-subject randomized sham-controlled design, participants underwent (sham) removal of ∼ 50% of the band's fluid. Compared to sham-deflation (i.e., normal band constriction) of the band, in the deflation condition (i.e., decreasing restriction) participants showed significantly lower activation in the anterior (para)cingulate, angular gyrus, lateral occipital cortex, and frontal cortex in response to food images (p < 0.05, whole brain TFCE-based FWE corrected). Higher activation in the deflation condition was seen in the fusiform gyrus, inferior temporal gyrus, lingual gyrus, lateral occipital cortex. The findings of this within-subject randomized controlled pilot study suggest that constriction of the stomach through LAGB may indirectly alter brain activation in response to food cues. These neuronal changes may underlie changes in food craving and food preference that support sustained post-surgical weight-loss. Despite the small sample size, this is in agreement with and adds to the growing literature of post-bariatric surgery changes in behavior and control regions.

Bariatric Surgery in NAFLD

Currently, there are no approved medications to treat patients with nonalcoholic steatohepatitis (NASH) with fibrosis or cirrhosis. Although the management goal in these patients is weight reduction by 7-10% with lifestyle modifications, only less than 10% of patients achieve this target at 1-year, and fewer maintain the weight loss at 5 years. Bariatric surgery is an option that may be considered in those who fail to lose weight by lifestyle changes. Bariatric surgery has been shown to improve liver histology including fibrosis secondary to NASH, in addition to other benefits including an improvement or resolution of type 2 diabetes mellitus, dyslipidemia, and hypertension, and a reduction of cardiovascular morbidity or mortality. There are no guidelines of bariatric surgery indications for the management of NASH. The purpose of this review is to critically appraise the current knowledge of the role of bariatric surgery and the potential mechanisms for its perceived benefits in the management of patients with NASH-related liver disease.

Mechanisms of Weight Loss After Obesity Surgery

Obesity surgery remains the most effective treatment for obesity and its complications. Weight loss was initially attributed to decreased energy absorption from the gut but has since been linked to reduced appetitive behavior and potentially increased energy expenditure. Implicated mechanisms associating rearrangement of the gastrointestinal tract with these metabolic outcomes include central appetite control, release of gut peptides, change in microbiota, and bile acids. However, the exact combination and timing of signals remain largely unknown. In this review, we survey recent research investigating these mechanisms, and seek to provide insights on unanswered questions over how weight loss is achieved following bariatric surgery which may eventually lead to safer, nonsurgical weight-loss interventions or combinations of medications with surgery.

Laparoscopic Banded One Anastomosis Gastric Bypass: A Single-Center Series

INTRODUCTION

Laparoscopic one anastomosis gastric bypass (LOAGB) is a relatively new procedure for the treatment of morbid obesity and related comorbidities. On average, this procedure results in good postoperative weight loss with a low complication rate. Recent publications suggest that dumping syndrome and weight regain might be reduced by placing a silicone ring over the gastric pouch during the procedure, so called laparoscopic banded one anastomosis gastric bypass (LBOAGB).

METHODS

86 patients undergoing LBOAGB between 2018 and 2020 were enrolled in this retrospective study. Hospital records were used to assess weight loss, comorbidity resolution, and any complications either in the short or medium term.

RESULTS

54 Female and 32 male patients were included with a mean age of 43 years (25-64), preoperative body mass index of 42 kg/m² (35-49), and preoperative weight of 114 kg (86-162). Thirty-four patients presented with type 2 diabetes (39.5%), 42 patients (49%) diagnosed with hypertension, 24 presented with OSAS (28%), and 21 (24%) hypercholesterolaemia patients were included. In total, 36 patients were diagnosed with multiple comorbidities. The operative data showed an average operative time of 48 minutes with 3.4% of patients suffering from early (minor) complications and 2.3% with a late (minor) complication. One patient required reoperation due to intra-abdominal bleeding. The median length of hospital stay was 2.5 days. Median follow-up was 18 months (5-36). In that period, no patient required ring removal or conversion to Roux-en-Y gastric bypass surgery. Food intolerance/vomiting was present in 1 patient (1.1%), bile reflux was present in 1 patient (1.1%), and no stomal ulcers were observed. Mean % excess weight loss at 12 and 24 months was 72% and 80%, respectively. Fifty-two out of 86 patients (60%) had a complete resolution of comorbidities. A CONUT score >2 (mild malnutrition) was found in 40% of patients, while a CONUT score 0-1 was found in 60% of patients.

CONCLUSION

LBOAGB shows promising results in terms of safety and efficacy in the short term. Further prospective studies will be required to evaluate the consistency of the results in the long term.

Biomechanical Investigation of the Stomach Following Different Bariatric Surgery Approaches

Background: The stomach is a hollow organ of the gastrointestinal tract, on which bariatric surgery (BS) is performed for the treatment of obesity. Even though BS is the most effective treatment for severe obesity, drawbacks and complications are still present because the intervention design is largely based on the surgeon’s expertise and intraoperative decisions. Bioengineering methods can be exploited to develop computational tools for more rational presurgical design and planning of the intervention. Methods: A computational mechanical model of the stomach was developed, considering the actual complexity of the biological structure, as the nonhomogeneous and multilayered configuration of the gastric wall. Mechanical behavior was characterized by means of an anisotropic visco-hyperelastic constitutive formulation of fiber-reinforced conformation, nonlinear elastic response, and time-dependent behavior, which assume the typical features of gastric wall mechanics. Model applications allowed for an analysis of the influence of BS techniques on stomach mechanical functionality through different computational analyses. Results: Computational results showed that laparoscopic sleeve gastrectomy and endoscopic sleeve gastroplasty drastically alter stomach capacity and stiffness, while laparoscopic adjustable gastric banding modestly affects stomach stiffness and capacity. Moreover, the mean elongation strain values, which are correlated to the mechanical stimulation of gastric receptors, were elevated in laparoscopic adjustable gastric banding compared to other procedures. Conclusions: The investigation of stomach mechanical response through computational models provides information on different topics such as stomach capacity and stiffness and the mechanical stimulation of gastric receptors, which interact with the brain to control satiety. These data can provide reliable support to surgeons in the presurgical decision-making process.

Preoperative Binge Eating and Weight Loss After Bariatric Surgery: A Systematic Review and Meta-analysis

BACKGROUND

Several studies have investigated if bariatric surgery candidates with binge eating disorder (BED) are at risk for suboptimal postoperative weight loss. The aim of this systematic review with meta-analysis was to evaluate the association between binge eating diagnosed preoperatively and weight loss after bariatric surgery.

METHODS

MEDLINE, EMBASE, CENTRAL, LILACS, and other specialized databases were searched on August 2020. Clinical trials and observational studies including individuals who had undergone any type of bariatric surgical treatment with preoperative evaluation of BED and at least one postoperative measure of weight were initially selected. Four reviewers independently screened for eligibility. The mean difference was calculated using the random-effects model.

RESULTS

Nineteen studies, comprising 3223 participants (80.25% women; median age 41 years), met the inclusion criteria for meta-analysis. At 6 months postoperative, the percentage of total weight loss (%TWL) was not significantly different between BED and non-BED groups [6 studies, 914 participants: - 0.75% (95% CI, - 2.79 to 1.29; I² = 0%)], even when analyzing only those three studies that included gold standard assessment tools. No significant differences were found at 12, 24, 36, or 60 months.

CONCLUSIONS

Pre-bariatric BED seems to have little or no influence on weight loss after surgery. However, many questions remain unanswered because of the use of different measures across studies. The heterogeneity among studies emphasizes the importance of investigators using the same assessment measures.

Treatment of Obesity in Mitigating Metabolic Risk

Through diverse mechanisms, obesity contributes to worsened cardiometabolic health and increases rates of cardiovascular events. Effective treatment of obesity is necessary to reduce the associated burdens of diabetes mellitus, cardiovascular disease, and death. Despite increasing cardiovascular outcome data on obesity interventions, only a small fraction of the population with obesity are optimally treated. This is a primary impetus for this article in which we describe the typical weight loss, as well as the associated impact on both traditional and novel cardiovascular disease risk factors, provided by the 4 primary modalities for obtaining weight loss in obesity-dietary modification, increasing physical activity, pharmacotherapy, and surgery. We also attempt to highlight instances where changes in metabolic risk are relatively specific to particular interventions and appear at least somewhat independent of weight loss. Finally, we suggest important areas for further research to reduce and prevent adverse cardiovascular consequences due to obesity.

Pre-operative Restraint and Post-operative Hunger, Disinhibition and Emotional Eating Predict Weight Loss at 2 Years Post-laparoscopic Adjustable Gastric Banding

INTRODUCTION

A principal mechanism of action in bariatric surgery is reduction in calorie consumption due to decreased hunger and increased satiety. Patients' ability to perceive post-operative changes to their hunger is therefore central to optimal results. This study examined factors that may impact how patients perceive post-operative hunger and how perception of hunger impacts eating and subsequent weight loss after laparoscopic adjustable gastric banding (LAGB).

METHODS

Patients undertaking LAGB (n = 147) provided pre-surgery and 2-year weight loss data and pre-surgery and 12-month psychological data (perception of hunger, disinhibition related to eating, emotional eating).

RESULTS

Path analysis demonstrated that patients with lower levels of pre-surgery cognitive restraint over eating experienced significantly greater reduction in perception of hunger at 12 months post-surgery. Perceived reduction in hunger was significantly associated with lower levels of both emotional eating and disinhibited eating. Finally, reduced emotional eating at 12 months significantly predicted 9% of the variance in percentage of total weight loss (%TWL) at 2 years after surgery.

CONCLUSION

These initial findings suggest that preparation for bariatric surgery may be enhanced by psychoeducation regarding cognitive restraint over eating and its effect on hunger perception. In addition, psychological treatment that focuses on identifying and responding to changes in hunger may contribute to improved outcomes for those who have difficulty adjusting to post-operative eating behaviours.

Banded Sleeve Gastrectomy Improves Weight Loss Compared to Nonbanded Sleeve: Midterm Results from a Prospective Randomized Study

BACKGROUND

Weight regain after laparoscopic sleeve gastrectomy (LSG) is nowadays a growing concern. Sleeve dilatation and loss of food restriction is considered the main mechanism. The placement of a silicon ring around the gastric tube seems to give benefits in the short term. We report the results of a randomized study comparing LSG and laparoscopic banded sleeve gastrectomy (LBSG) over a 4-year follow-up.

OBJECTIVES

To evaluate the efficacy of banded sleeve gastrectomy compared to standard sleeve in the midterm.

METHODS

Between 01/2014 and 01/2015, we randomly assigned 50 patients to receive one of the two procedures. Patients' management was exactly the same, apart from the band placement. We analyzed differences in weight loss, operative time, complication rate, and mortality, with a median follow-up of 4 years.

RESULTS

Twenty five patients were assigned to receive LSG (Group A) and 25 LBSG (Group B). The mean preoperative BMI (body mass index) was 47.3 ± 6.58 kg/m² and 45.95 ± 5.85 kg/m², respectively. There was no significant difference in the operative time. No intraoperative or postoperative complications occurred. At 12-month follow-up, the mean BMI was 29.72 ± 4.40 kg/m² in Group A and 27.42 ± 4.47 kg/m² in Group B (p=0.186). After a median follow-up of 4 years, the mean BMI in Group B was significantly lower than Group A (24.10 ± 4.52 kg/m² vs 28.80 ± 4.62 kg/m²; p=0.00199).

CONCLUSIONS

LBSG is a safe procedure, with no impact on postoperative complications. The banded sleeve showed a significant greater weight loss in the midterm follow-up. Considering the issue of weight regain observed after LSG, the placement of a perigastric ring during the first procedure may be a strategy to improve the results. This trial is registered with NCT04228185.

Upper Gastrointestinal Function in Morbidly Obese Adolescents Before and 6 Months After Gastric Banding

BACKGROUND

The effects of laparoscopic adjustable gastric band (LAGB) placement on upper gastrointestinal tract function in obese adolescents are unknown. Therefore, our aim was to determine the short-term effects of LAGB on esophageal motility, gastroesophageal reflux, gastric emptying, appetite-regulatory hormones, and perceptions of post-prandial hunger and fullness.

METHODS

This study was part of a prospective cohort study (March 2009-December 2015) in one tertiary referral hospital. The study included obese adolescents (14-18 years) with a body mass index (BMI) > 40 (or ≥ 35 with comorbidities). Gastric emptying was assessed by ¹³C-octanoic acid breath test, pharyngeal, and esophageal motor function by high-resolution manometry with impedance (HRIM), and appetite and other perceptions using 100-mm visual analogue scales. Dysphagia symptoms were scored using a Dakkak questionnaire. Data were compared pre- and post-LAGB placement and at a 6-month follow-up.

RESULTS

Based upon analysis of 15 adolescents, at the 6-month follow-up, LAGB placement: (i) led to a significant reduction in weight and BMI; (ii) increased fullness and decreased hunger post-meal; (iii) increased symptoms of dysphagia after solid food; and, despite these effects, (iv) caused little or no changes to appetite hormones, while (v) effects on gastric emptying, esophageal motility, esophageal bolus transport, and esophageal emptying were not significant.

CONCLUSION

In adolescents, LAGB improved BMI and altered the sensitivity to nutrients without significant effects on upper gastrointestinal tract physiology at the 6-month follow-up.

Detailed Description of Change in Serum Cholesterol Profile with Incremental Weight Loss After Restrictive Bariatric Surgery

INTRODUCTION

Dyslipidemia affects up to 75% of morbidly obese individuals and is a key driver of cardiovascular disease. Weight loss is an established strategy to improve metabolic risk, including dyslipidemia. We aimed to determine weight loss goals for resolution of serum lipid abnormalities, by measuring improvements during progressive weight loss in obese individuals.

METHODS

We performed a prospective cohort study of obese individuals with the metabolic syndrome undergoing adjustable gastric banding. Lipid levels were monitored monthly for 9 months, then three monthly until 24 months.

RESULTS

There were 101 participants included, age 47.4 ± 10.9 years with body mass index 42.6 ± 5.9 kg/m². At 24 months, total body weight loss (TBWL) was 18.3 ± 7.9%. This was associated with significant improvements in high-density lipoprotein (HDL) (1.18 vs 1.47, p < 0.001), triglyceride (2.0 vs 1.4, p < 0.001), and total cholesterol to HDL ratio (TC:HDL) (4.6 vs 3.6, p < 0.001). Over this time, progressive and linear improvements in HDL, triglycerides, and TC:HDL were seen with incremental weight loss (observed at 2.5% TBWL intervals). Significant improvements occurred after a threshold weight loss of 7.5-12.5% TBWL was achieved, with odds ratio (OR) 1.48-2.50 for normalization. These odds improved significantly with increasing weight loss (OR 18.2-30.4 with > 25% TBWL). Despite significant weight loss, there was no significant change in low-density lipoprotein (LDL).

CONCLUSION

Significant improvements in triglycerides, HDL, and TC:HDL occur after 7.5-12.5% TBWL, with ongoing benefit after greater weight loss. LDL needs to be addressed independently, as this was not observed to respond to weight loss alone.

TRIAL REGISTRATION NUMBER

Australian Clinical Trials Registry (ACTRN12610000049077).

Metabolic Surgery: Weight Loss, Diabetes, and Beyond

The alarming rise in the worldwide prevalence of obesity is paralleled by an increasing burden of type 2 diabetes mellitus. Metabolic surgery is the most effective means of obtaining substantial and durable weight loss in individuals with obesity. Randomized trials have recently shown the superiority of surgery over medical treatment alone in achieving improved glycemic control, as well as a reduction in cardiovascular risk factors. The mechanisms seem to extend beyond the magnitude of weight loss alone and include improvements in incretin profiles, insulin secretion, and insulin sensitivity. Moreover, observational data suggest that the reduction in cardiovascular risk factors translates to better patient outcomes. This review describes commonly used metabolic surgical procedures and their current indications and summarizes the evidence related to weight loss and glycemic outcomes. It further examines their potential effects on cardiovascular outcomes and mortality and discusses future perspectives.

Banded Sleeve Gastrectomy: Better Long-Term Results? A Long-Term Cohort Study Until 5 Years Follow-Up in Obese and Superobese Patients

INTRODUCTION

The failure rate of the laparoscopic sleeve gastrectomy (LSG) is increasing. Gastric pouch dilation is frequently suggested to be one of the causes for the failure. The banded laparoscopic sleeve gastrectomy (BLSG) has been proposed to overcome this complication. This is the first study that reports the long-term outcome (> 5 years) of BLSG in obese and superobese patient population.

MATERIALS AND METHODS

One hundred and forty-seven patients (n = 51, non-banded LSG (NLSG)/n = 96, BLSG) were followed up for 5 years. Patients were evaluated for % excess weight loss (%EWL), % excess body mass index loss (%EBMIL), weight regain, BMI, and complications. Weight loss analysis was also done between banded and non-banded superobese patient populations.

RESULT

There was statistical significant difference between two groups at each given time point in terms of %EWL and %EBMIL. NLSG group had higher weight loss failure rate (35.2%) and weight regain (19.6%) at the 5-year follow-up compared to BLSG group (P < 0.001). There was no statistical significant difference in weight loss between obese and superobese BLSG group. The complication rates were more with BLSG group (14.5%) compared to NLSG group (9.8%); no signs of band slippage, erosion, or migration were seen. There was no mortality seen.

CONCLUSION

BLSG surgery was found to be safe and effective in maintaining weight loss on the long term compared to the NLSG group with low incidence of band-related problems. Additionally, the NLSG group had a higher rate of weight loss failure and weight regain at 5 years compared to the BLSG group.

Gut as an emerging organ for the treatment of diabetes: focus on mechanism of action of bariatric and endoscopic interventions

Increasing worldwide prevalence of type 2 diabetes mellitus and its accompanying pathologies such as obesity, arterial hypertension and dyslipidemia represents one of the most important challenges of current medicine. Despite intensive efforts, high percentage of patients with type 2 diabetes does not achieve treatment goals and struggle with increasing body weight and poor glucose control. While novel classes of antidiabetic medications such as incretin-based therapies and gliflozins have some favorable characteristics compared to older antidiabetics, the only therapeutic option shown to substantially modify the progression of diabetes or to achieve its remission is bariatric surgery. Its efficacy in the treatment of diabetes is well established, but the exact underlying modes of action are still only partially described. They include restriction of food amount, enhanced passage of chymus into distal part of small intestine with subsequent modification of gastrointestinal hormones and bile acids secretion, neural mechanisms, changes in gut microbiota and many other possible mechanisms underscoring the importance of the gut in the regulation of glucose metabolism. In addition to bariatric surgery, less-invasive endoscopic methods based on the principles of bariatric surgery were introduced and showed promising results. This review highlights the role of the intestine in the regulation of glucose homeostasis focusing on the mechanisms of action of bariatric and especially endoscopic methods of the treatment of diabetes. A better understanding of these mechanisms may lead to less invasive endoscopic treatments of diabetes and obesity that may complement and widen current therapeutic options.

Serum Leptin, Obestatin, and Ghrelin Levels and Gastric Emptying Rates of Liquid and Solid Meals in Non-obese Rats with Roux-en-Y Bypass Surgery or Prosthesis Placement: Implications for the Role of Vagal Afferents

BACKGROUND

The present study aimed to investigate the effects of Roux-en-Y gastric bypass (RYGB) and prosthesis placement on gastric emptying rate in conjunction with serum ghrelin-obestatin-leptin responses in non-obese rats with intact or denervated afferent innervation.

METHODS

Under anesthesia, male Sprague-Dawley rats underwent either sham operation, RYGB, prosthesis, and/or Gregory cannula placement. Three weeks later, liquid or solid gastric emptying tests were performed and serum ghrelin, leptin and obestatin levels were measured.

RESULTS

Both prosthesis placement and RYGB surgery delayed non-nutrient liquid emptying; while solid nutrient emptying was delayed only by RYGB. Nutrient-dependent (acid, hyperosmolal and peptone) delay in liquid emptying was abolished in rats with prosthesis. By vagal afferent denervation, delayed liquid emptying was abolished, while solid emptying was further delayed in rats with prosthesis. Ghrelin and obestatin levels were depressed in prosthesis-placed rats, but RYGB surgery had no impact on both levels. Leptin level was elevated in solid-food-given rats with prosthesis, but not changed in RYGB group, while it was reduced following liquid meal. All the changes observed in ghrelin, obestatin, or leptin levels in response to meal ingestion were reversed with vagal afferent denervation.

CONCLUSIONS

Both RYGB and prosthesis placement had delaying effects on gastric emptying rate of non-obese rats. Our results indicate that the short-term changes in gastric motility and hormone responses induced by volume reduction are reversed by afferent denervation, suggesting that sparing the vagal innervation could be essential for reaching optimum motility and hormone changes expected after bariatric surgery.

Dilatation of Sleeve Gastrectomy: Myth or Reality?

OBJECTIVES

The success of longitudinal sleeve gastrectomy (LSG) is perceived as being potentially limited by dilatation of the remaining gastric tube during the follow-up. The aim of this prospective study was to determine the incidence and the characteristics of sleeve dilatation during the first post-operative year.

MATERIALS AND METHODS

Gastric volumetry using 3D gastric computed tomography with gas expansion was performed in 54 successive subjects who underwent an LSG for morbid obesity at 3 and 12 months following surgery. Total gastric volume, volume of the gastric tube and the antrum, and diameter of the gastric tube were assessed after multiplanar reconstructions. An increase of at least 25 % of the total gastric volume was considered as sleeve dilatation. Percentage of excess BMI loss (%EBMIL) and daily caloric intakes were recorded during the first 18 months.

RESULTS

Sixty-one percent of the subjects experienced sleeve dilatation 1 year after surgery. The gastric tube was mainly involved in the sleeve dilatation process (+91 %). Sleeve dilatation occurred especially in subjects with smaller total gastric volume at baseline (189 vs 236 ml, p = 0.02). Daily caloric intake was similar between the groups at each point of the follow-up. No difference concerning %EBMIL was observed between the groups during the 18 months of follow-up.

CONCLUSIONS

Sleeve dilatation occurred in more than 50 % of the patients. Dilatation was not necessarily linked to an increase of daily caloric intake and insufficient weight loss during the first 18 months following surgery. Small LSG at baseline is at higher risk of dilatation.

Weight loss after laparoscopic adjustable gastric band and resolution of the metabolic syndrome and its components

BACKGROUND

Substantial weight loss in the setting of obesity has considerable metabolic benefits. Yet some studies have shown improvements in obesity-related metabolic comorbidities with more modest weight loss. By closely monitoring patients undergoing bariatric surgery, we aimed to determine the effects of weight loss on the metabolic syndrome and its components and determine the weight loss required for their resolution.

METHODS

We performed a prospective observational study of obese participants with metabolic syndrome (Adult Treatment Panel III criteria) who underwent laparoscopic adjustable gastric banding. Participants were assessed for all criteria of the metabolic syndrome monthly for the first 9 months, then 3-monthly until 24 months.

RESULTS

There were 89 participants with adequate longitudinal data. Baseline body mass index was 42.4±6.2 kg m^-2 with an average age was 48.2±10.7 years. There were 56 (63%) women. Resolution of the metabolic syndrome occurred in 60 of the 89 participants (67%) at 12 months and 60 of the 75 participants (80%) at 24 months. The mean weight loss when metabolic syndrome resolved was 10.9±7.7% total body weight loss (TBWL). The median weight loss at which prevalence of disease halved was 7.0% TBWL (17.5% excess weight loss (EWL)) for hypertriglyceridaemia; 11% TBWL (26.1-28% EWL) for high-density lipoprotein cholesterol and hyperglycaemia; 20% TBWL (59.5% EWL) for hypertension and 29% TBWL (73.3% EWL) for waist circumference. The odds ratio for resolution of the metabolic syndrome with 10-12.5% TBWL was 2.09 (P=0.025), with increasing probability of resolution with more substantial weight loss.

CONCLUSIONS

In obese participants with metabolic syndrome, a weight loss target of 10-12.5% TBWL (25-30% EWL) is a reasonable initial goal associated with significant odds of having metabolic benefits. If minimal improvements are seen with this initial target, additional weight loss substantially increases the probability of resolution.

Improving efficacy of the adjustable gastric band: studies of the use of adjuvant approaches in a rodent model

BACKGROUND

The laparoscopic adjustable gastric band (AGB) has been effective in reducing excess weight by approximately 50% for at least 16 years. However, as with all weight loss approaches, reduction in weight resulting from bariatric surgery is associated with a compensatory reduction in energy expenditure, which may confound and limit weight loss. Adjuvant therapies that reduce food intake and increase energy expenditure may be used to improve weight loss outcomes by ameliorating, or even reversing, this reduction in energy expenditure.

METHODS

Rats were either fitted with an AGB or were sham operated and received one of 2 adjunctive pharmacologic treatments, (1) thyroxine or (2) bupropion/naltrexone (Contrave), at a range of doses and matched with vehicle controls (n = 6-8/group) over a 4-week period of combined treatments. Metabolic parameters including food intake, weight, fat mass, and energy expenditure in brown adipose tissue (BAT), whole body calorimetry, and physical activity were assessed.

RESULTS

Inflation of the AGB caused a reduction in weight gain that was further enhanced by cotreatment with either thyroxine or Contrave (P<.05). Thyroxine completely ameliorated the reduction in AGB-induced BAT thermogenesis and significantly improved weight loss, particularly in fat mass. Contrave also augmented the loss of weight and fat mass associated with the AGB and increased BAT thermogenesis in banded rats even at doses below that required to change food intake.

CONCLUSION

Adjuvant therapies can improve the efficacy of the AGB, at least in part by negating the compensatory reduction in energy expenditure, but also via a combined effect on food intake.

Mesentero-axial gastric volvulus after removal of laparoscopic adjustable gastric band

Despite the decreasing popularity of gastric banding, a large number of patients still have a band in situ. Although immediate postoperative complications are relatively rare, long-term complications of gastric banding are more common but are not reported to occur after band removal. We report a case of gastric volvulus and subsequent ischaemic perforation in a patient shortly after band removal, resulting in emergency laparotomy and total gastrectomy. Severe continuing pain persisting after band deflation and even gastric band removal should be treated as an emergency and urgent investigation should not be delayed.

Laparoscopic Sleeve Gastrectomy versus Laparoscopic Banded Sleeve Gastrectomy: First Prospective Pilot Randomized Study

Introduction. The placement of ring or band around the gastric tube might prevent the dilation after Laparoscopic Sleeve Gastrectomy (LSG). We describe the first randomized study comparing LSG and Laparoscopic Banded Sleeve Gastrectomy (LBSG). Material and Method. Fifty obese patients were enrolled in the study between January 2014 and January 2015. We analysed differences in operative time, complication rate, mortality, and BMI between the two groups over a period of 12 months. Results. Twenty-five patients received LSG (group A) and 25 LBSG (group B). The mean preoperative BMI was 47.3 ± 6.58 kg/m² and 44.95 ± 5.85 kg/m², respectively, in the two groups. There was no statistical relevant difference in operative time. No intraoperative complications occurred. Mean BMI registered after 3, 6, and 12 months in groups A and B, respectively, were 37.86 ± 5.72 kg/m² and 37.58 ± 6.21 kg/m² (p = 0.869), 33.64 ± 6.08 kg/m² and 32.03 ± 5.24 kg/m² (p = 0.325), and 29.72 ± 4.40 kg/m² and 27.42 ± 4.47 kg/m² (p = 0.186); no statistical relevant difference was registered between the two groups. Conclusion. LBSG is a safe and feasible procedure. The time required for the device positioning did not influence significantly the surgical time. The results of bodyweight loss did not document any statistically significant differences among the two groups, even though LBSG group showed a mean BMI slightly lower than that of the control group.

Aversion learning can reduce meal size without taste avoidance in rats

OBJECTIVE

Nausea and aversive food responses are commonly reported following bariatric surgery, along with post-surgical reduction in meal size. This study investigates whether a meal size limit can be conditioned by associating large meals with aversive outcomes.

METHODS

In rats, the intake of meals exceeding a pre-defined size threshold was paired with lithium chloride-induced gastric illness, and the effects on self-determined food intakes and body weight were measured.

RESULTS

Rats given LiCl contingent on the intake of a large meal learned to reliably reduce intake below this meal size threshold, while post-meal saline or LiCl before meals did not change meal size. It was further demonstrated that this is not a conditioned taste aversion and that this effect transferred to foods not explicitly trained. Finally, when rats received LiCl following all large meals, the number of small meals increased, but total food intake and body weight decreased.

CONCLUSIONS

While further work is needed, this is the first demonstration that meal size may be conditioned, using an aversion procedure, to remain under a target threshold and that this effect is distinct from taste avoidance. Corresponding reduction in food intake and body weight suggests that this phenomenon may have implications for developing weight loss strategies and understanding the efficacy of bariatric surgery.

Laparoscopic adjustable gastric banding outcomes in patients with gastroesophageal reflux disease or hiatal hernia

BACKGROUND

Gastroesophageal reflux disease (GERD) and hiatal hernia (HH) are classically considered contraindications to bariatric restrictive procedures. Despite the high number of studies that have been published, the relationship between laparoscopic adjustable gastric banding (LAGB) and GERD/HH is still not clear.

METHODS

We have retrospectively analyzed the outcomes of LAGB in patients operated in 2010 with HH and/or GERD. The gastroesophageal reflux was diagnosed if the patients had heartburn and regurgitation more than once a week, and hiatal hernia was assessed by esophagogastroduodenoscopy and/or upper GI radiogram with swallow. Data on heartburn, assumption of antacid medication, weight loss, and rate of complications in both patients with and without GERD or HH were collected.

RESULTS

One hundred and twenty patients that underwent LAGB at our department were enrolled in our study; 40 had symptoms of GERD and 25 had hiatal hernia preoperatively. There was no difference of percentage excess weight loss (%EWL) at 12 months (45.4 ± 20.4 vs 4.6 ± 19.5 kg/m(2)) and 36 months follow-up (49.4 ± 16.5 vs 48.6 ± 18.9 kg/m(2)) between asymptomatic patients and patients with HH or GERD symptoms. The number of patients with preoperative heartburn (40 to 10) and/or assumption of antacid drugs (38 to 7) significantly decreased after LAGB CONCLUSIONS: LAGB is an effective and safe surgical treatment for morbidly obesity in patients with GERD or HH, since it induces both a significant weight loss and an improvement of reflux symptoms.

Concurrent Large Para-oesophageal Hiatal Hernia Repair and Laparoscopic Adjustable Gastric Banding: Results from 5-year Follow Up

OBJECTIVE

The objective of the study is to identify the efficacy and safety of combining laparoscopic adjustable gastric banding with repair of large para-oesophageal hernias.

BACKGROUND

Para-oesophageal hernias are more common in the obese with higher recurrence rates following repair. The effect and safety of combining para-oesophageal hernia repair with laparoscopic adjustable gastric banding is unknown.

METHODS

One-hundred fourteen consecutive patients undergoing primary laparoscopic adjustable gastric banding with concurrent repair of a large para-oesophageal hernia were prospectively identified and matched to a control group undergoing primary laparoscopic adjustable gastric banding only. Weight loss and complication data were retrieved from a prospectively maintained database, and a standardised bariatric outcome questionnaire was used to assess post-operative symptoms, satisfaction with surgery and satiety scores.

RESULTS

At a mean follow up of 4.9 ± 2.1 years, total weight loss was 16.4 ± 9.9% in the hernia repair group and 17.6 ± 12.6% in the control group (p = 0.949), with 17 vs. 11% loss to follow up rates (p = 0.246). No statistically significant difference in revisional surgery rate and symptomatic recurrence of hiatal hernia was documented in four patients in the hernia repair group (3.5%). No statistically significant difference in mean reflux (9.9 vs. 10.3, p = 0.821), dysphagia (20.7 vs. 20.1, p = 0.630) or satiety scores was identified.

CONCLUSIONS

Concurrent repair of large para-oesophageal hiatal hernia and laparoscopic adjustable gastric banding placement is safe and effective both in terms of symptom control and weight loss over the intermediate term. In obese patients with large hiatal hernias, consideration should be given to combining repair of the hernia with a bariatric procedure.

LAP-BAND for BMI 30-40: 5-year health outcomes from the multicenter pivotal study

BACKGROUND

We performed a 5-year multicenter study to evaluate the safety and effectiveness of the LAP-BAND System surgery (LBS) in patients with obesity with a body mass index (BMI) of 30-39.9 kg m(-)(2). This pivotal study was designed to support LBS application to the US Food and Drug Administration for broadening the indications for surgery and the lower BMI indication was approved with 1-year data in 2011, with the intention to complete the 5-year evaluation.

OBJECTIVES

To present broad health outcome data including weight change, patient reported outcomes, comorbidity change and complications during the 5-year study.

SETTING

The study was conducted at seven US private practice clinical trial sites.

METHODS

We enrolled 149 BMI 30-39.9 subjects into a 5-year, multicenter, longitudinal, prospective post-approval study. Data for those completing each time point are presented.

RESULTS

The predefined target of at least 30% excess weight loss was achieved by more than 76% of subjects by 1-year and at every year thereafter during the 5-year study. Mean percentage weight loss at 5 years was 15.9±12.4%. Sustained weight loss was accompanied by sustained improvement in generic and weight-specific quality of life, symptoms of depression and the prevalence of binge-eating disorder. The number of subjects with normal fasting triglyceride, high-density lipoprotein cholesterol, plasma glucose and HbA1c increased significantly between baseline and 5 years. Fifty-four months after LBS implantation, the rate of device explants without replacement was 5.4%; however, the rate of explants increased to 12.1% by month 60 owing to no cost-elective band removals offered to subjects at study exit. No deaths or unanticipated adverse device effects were reported.

CONCLUSIONS

The LBS is safe and effective for people with BMI 30-39.9 with demonstrated improvements in weight loss, comorbidities and quality of life, and with a low explant rate through 5 years following treatment.

To band or not to band--early results of banded sleeve gastrectomy

Laparoscopic sleeve gastrectomy (LSG) is the procedure with the fastest growing numbers worldwide. Although excellent weight loss can be achieved, one major obstacle of LSG is weight regain due to sleeve dilatation. Banded sleeve gastrectomy (BLSG) has been described as an option to counteract sleeve dilatation and ameliorate weight loss over time. In a retrospective study, we analysed 25 patients who underwent BLSG using a MiniMizer® ring. Twenty five patients who had previously undergone a conventional LSG were selected for matched-pair analysis. Patient follow-up was 12 months in both groups. Mean preoperative BMI was 56.1 ± 7.2 kg/m(2) for BLSG and 57.0 ± 6.3 kg/m(2) for LSG, P = 0.522. Operative time was significantly shorter for BLSG (53 ± 27 min vs. 68 ± 20 min, P = 0.0025). Excess weight loss (%EWL) was equal in both groups with %EWL at 12 months of 58.0 ± 14.6 % for BSLG patients vs. 58.4 ± 19.2 % for LSG patients. There was no procedure-related mortality in either group. At 12 months postoperative, vomiting was significantly increased in BSLG patients (OR 6.75, P = 0.035). New onset reflux was equal in both groups (OR 0.67, P = 0.469). Ring implantation does not increase the duration of surgery or early surgical complications. Weight loss in the first follow-up year is not influenced, but the incidence of vomiting is raised after 12 months when patients start to increase eating volume.

Food tolerance and diet quality following adjustable gastric banding, sleeve gastrectomy and Roux-en-Y gastric bypass

OBJECTIVE

The effects of food tolerance (if any) on diet quality several years post-surgery remain unclear. Our study aimed to assess food tolerance and diet quality after three bariatric procedures; adjustable gastric banding (AGB), sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGBP), 2â??4 years post-surgery.

METHODS

This prospective, cross-sectional study assessed weight loss, food tolerance and diet quality in 130 subjects (14 obese pre-surgical controls, 13 AGB, 62 SG and 41 RYGBP). Inclusion criteria selected patients who underwent bariatric surgery between 1 January 2007 and 31 December 2008, at a single bariatric clinic. Non-parametric tests (Kruksalâ??Wallis and Mannâ??Whitney) along with Spearman's correlation coefficient analysis were used.

RESULTS

Superior food tolerance was reported by the control (24.5), SG (24.0) and RYGBP (22.0) groups, compared with the AGB group (15.5; P < 0.001). The control and AGB groups consumed significantly more high-calorie extra foods (9.2 and 7.7 daily serves respectively) compared with the SG (3.4 serves) and RYGBP (4.0 serves) groups. There were several significant correlations between food tolerance and dietary intake including breads and cereals and meat and meat alternatives.

CONCLUSION

The control and AGB groups consumed significantly more high-calorie extra foods, a result that was paralleled by poor weight loss and food tolerance outcomes for the AGB group. A significant positive relationship between food tolerance and diet quality was established. Poor food tolerance and thus compromised diet quality need to be considered as post-surgical complications of the AGB procedure.

Interventions to improve long-term weight loss in patients following bariatric surgery: challenges and solutions

Bariatric surgery aims to provide long-term weight loss and improvement in weight-related comorbidities. Unfortunately, some patients do not achieve predicted weight loss targets and many regain a portion of their lost weight within 2-10 years postsurgery. A review of the literature found that behavioral, dietary, psychological, physical, and medical considerations can all play a role in suboptimal long-term weight loss. Recommendations to optimize long-term weight loss include ensuring that the patient understands how the procedure works, preoperative and postoperative education sessions, tailored nutritional supplements, restraint with liquid kilojoules, pureed foods, grazing and eating out of the home, an average of 60 minutes of physical activity per day, and lifelong annual medical, psychological, and dietary assessments.

Could the improvement of obesity-related co-morbidities depend on modified gut hormones secretion?

Obesity and its associated diseases are a worldwide epidemic disease. Usual weight loss cures - as diets, physical activity, behavior therapy and pharmacotherapy - have been continuously implemented but still have relatively poor long-term success and mainly scarce adherence. Bariatric surgery is to date the most effective long term treatment for morbid obesity and it has been proven to reduce obesity-related co-morbidities, among them nonalcoholic fatty liver disease, and mortality. This article summarizes such variations in gut hormones following the current metabolic surgery procedures. The profile of gut hormonal changes after bariatric surgery represents a strategy for the individuation of the most performing surgical procedures to achieve clinical results. About this topic, experts suggest that the individuation of the crosslink among the gut hormones, microbiome, the obesity and the bariatric surgery could lead to new and more specific therapeutic interventions for severe obesity and its co-morbidities, also non surgical.

Development of minimally invasive techniques for management of medically-complicated obesity

The field of bariatric surgery has been rapidly growing and evolving over the past several decades. During the period that obesity has become a worldwide epidemic, new interventions have been developed to combat this complex disorder. The development of new laparoscopic and minimally invasive treatments for medically-complicated obesity has made it essential that gastrointestinal physicians obtain a thorough understanding of past developments and possible future directions in bariatrics. New laparoscopic advancements provide patients and practitioners with a variety of options that have an improved safety profile and better efficacy without open, invasive surgery. The mechanisms of weight loss after bariatric surgery are complex and may in part be related to altered release of regulatory peptide hormones from the gut. Endoscopic techniques designed to mimic the effects of bariatric surgery and endolumenal interventions performed entirely through the gastrointestinal tract offer potential advantages. Several of these new techniques have demonstrated promising, preliminary results. We outline herein historical and current trends in the development of bariatric surgery and its transition to safer and more minimally invasive procedures designed to induce weight loss.

Pre-operative weight loss does not predict weight loss following laparoscopic adjustable gastric banding

BACKGROUND

This study aimed to test the hypothesis that the amount of weight lost on a mandatory 2-week pre-operative very-low-calorie diet (VLCD) would predict the longer-term outcomes of laparoscopic adjustable gastric banding (LAGB).

METHODS

All patients treated with a primary LAGB from 21 October 2008 until 30 June 2010, who were prescribed a 2-week pre-operative VLCD, have been included in the study. Patient age, weight, BMI and excess weight (defined as weight above a BMI of 25) were extracted on the day of first visit, day of surgery and at the post-operative visits at 3, 12 and 24 months. From these data, percent excess weight loss (EWL) was calculated and compared at all time points.

RESULTS

The weight loss achieved on a mandatory 2-week pre-operative diet did not predict weight outcomes at 2 years (r = -0.008; p = 0.931). Using multivariate analysis, the best predictor of 24-month percent EWL was percent EWL at 3 months post operation (sr(2) = 0.34; p = 0.003).

CONCLUSIONS

Results from a pre-operative diet should not be used to predict the ultimate outcome of bariatric surgery. The weight loss at 3 months following LAGB was a strong predictor of longer-term outcomes. There may be potential for improving longer-term results with LAGB by better supporting patients who are not achieving good weight loss at this early time point.

Gender influence on long-term weight loss after three bariatric procedures: gastric banding is less effective in males in a retrospective analysis

BACKGROUND

Identifying factors that influence weight loss after bariatric surgery is one way to predict a successful surgical outcome. Knowledge of the effect of gender on weight loss after bariatric surgery has not been well demonstrated in the literature despite being noted in every day practice. The aim of this study was to find the influence of gender on long-term weight loss after bariatric surgery.

METHODS

A retrospective analysis of data retrieved from a prospectively maintained bariatric database was conducted.

RESULTS

The study included 640 consecutive patients. Their mean age was 38 ± 10 years, mean preoperative body mass index was 44.9 ± 8.4 kg/m2, and mean preoperative excess weight (EW %) was 108.3 ± 38.4%. The mean of the average excess weight loss (EWL %) was 43.3 ± 42.4%. Three procedures were utilized: Roux-en-Y gastric bypass (RYGB), vertical banded gastroplasty (VBG), and gastric banding (GB). Both VBG and RYGB induced significantly more EWL % than GB (d = 22.1%, p < 0.001 and d = 16, p = 0.02, respectively). In patients who underwent VBG and GB, males had significantly lower preoperative EW % (Student t = -4.86, p < 0.001, and Student t = 4.69, p < 0.001, respectively), and postoperative mean of the average EWL % (Student t = -2.43, p = 0.016, and Student t = -3.33, p = 0.002, respectively) than females. In patients who underwent RYGB, there were no differences in the preoperative EW % (t = -1.03, p = 0.309) or the mean of the average EWL % (t = 0.406, p = 0.688). The simple linear regression model used to explain the variability in EWL %, accounted for by the variability in the preoperative EW %, was significant (F = 180, p < 0.001). Analysis of the residual errors in predicting the EWL % revealed no significant difference between males and females after VBG and after RYGB (t = 0.117, p = 0.907 and t = 1.052, p = 0.3, respectively), while it was significant after GB (t = -2.999, p = 0.003).

CONCLUSION

From our experience, we suggest that GB not to be offered as a first choice for obese male patients.

Can medical therapy mimic the clinical efficacy or physiological effects of bariatric surgery?

The number of bariatric surgical procedures performed has increased dramatically. This review discusses the clinical and physiological changes, and in particular, the mechanisms behind weight loss and glycaemic improvements, observed following the gastric bypass, sleeve gastrectomy and gastric banding bariatric procedures. The review then examines how close we are to mimicking the clinical or physiological effects of surgery through less invasive and safer modern interventions that are currently available for clinical use. These include dietary interventions, orlistat, lorcaserin, phentermine/topiramate, glucagon-like peptide-1 receptor agonists, dipeptidyl peptidase-4 inhibitors, pramlintide, dapagliflozin, the duodenal-jejunal bypass liner, gastric pacemakers and gastric balloons. We conclude that, based on the most recent trials, we cannot fully mimic the clinical or physiological effects of surgery; however, we are getting closer. A 'medical bypass' may not be as far in the future as we previously thought, as the physician's armamentarium against obesity and type 2 diabetes has recently got stronger through the use of specific dietary modifications, novel medical devices and pharmacotherapy. Novel therapeutic targets include not only appetite but also taste/food preferences, energy expenditure, gut microbiota, bile acid signalling, inflammation, preservation of β-cell function and hepatic glucose output, among others. Although there are no magic bullets, an integrated multimodal approach may yield success. Non-surgical interventions that mimic the metabolic benefits of bariatric surgery, with a reduced morbidity and mortality burden, remain tenable alternatives for patients and health-care professionals.

Mechanisms of changes in glucose metabolism and bodyweight after bariatric surgery

Bariatric surgery is the most effective treatment for obesity and also greatly improves glycaemic control, often within days after surgery, independently of weight loss. Laparoscopic adjustable gastric banding (LAGB) was designed as a purely restrictive procedure, whereas vertical sleeve gastrectomy (VSG) and Roux-en-Y gastric bypass (RYGB) induce changes in appetite through regulation of gut hormones, resulting in decreased hunger and increased satiation. Thus, VSG and RYBG more frequently result in remission of type 2 diabetes than does LAGB. With all three of these procedures, remission of diabetes is associated with early increases in insulin sensitivity in the liver and later in peripheral tissues; VSG and RYBG are also associated with improved insulin secretion and an exaggerated postprandial rise in glucagon-like peptide 1. The vagal pathway could have a role in the neurohumoral regulatory pathways that control appetite and glucose metabolism after bariatric surgery. Recent research suggests that changes in bile acid concentrations in the blood and altered intestinal microbiota might contribute to metabolic changes after surgery, but the mechanisms are unclear. In this Series paper, we explore the possible mechanisms underlying the effects on glucose metabolism and bodyweight of LAGB, VSG, and RYGB surgery. Elucidation of these mechanisms is providing knowledge about bodyweight regulation and the pathophysiology of type 2 diabetes, and could help to identify new drug targets and improved surgical techniques.

Mechanisms underlying weight loss after bariatric surgery

The clinical efficacy of bariatric surgery has encouraged the scientific investigation of the gut as a major endocrine organ. Manipulation of gastrointestinal anatomy through surgery has been shown to profoundly affect the physiological and metabolic processes that control body weight and glycaemia. The most popular bariatric surgical procedures are gastric bypass, adjustable gastric banding and vertical sleeve gastrectomy. Even though these procedures were designed with the aim of causing restriction of food intake and nutrient malabsorption, evidence suggests that their contributions to weight loss are minimal. Instead, these interventions reduce body weight by decreasing hunger, increasing satiation during a meal, changing food preferences and energy expenditure. In this Review, we have explored these mechanisms as well as their mediators. The hope is that that their in-depth investigation will enable the optimization and individualization of surgical techniques, the development of equally effective but safer nonsurgical weight-loss interventions, and even the understanding of the pathophysiology of obesity itself.

Airway management concerns in patient with gastric banding procedures

Laparoscopic adjustable gastric band (LAGB) is considered a relatively safe and effective treatment for obesity. Even after weight loss patients with LAGB are at increased risk of pulmonary aspiration during induction of general anaesthesia, possibly due to LAGB-induced anatomical and functional changes. We present a case of aspiration in a patient with LAGB following significant weight loss and 14 h of preoperative fasting and review the literature. In the presence of LAGB we propose specific anaesthesia management at least consisting of anti-Trendelenburg positioning; avoidance of mask-ventilation; use of the local rapid sequence induction strategy with endotracheal intubation and fully awake extubation.

Mineral malnutrition following bariatric surgery

Moderate/severe obesity is on the rise in the United States. Weight management includes bariatric surgery, which is effective and can alleviate morbidity and mortality from obesity-associated diseases. However, many individuals are dealing with nutritional complications. Risk factors include: 1) preoperative malnutrition (e.g., vitamin D, iron); 2) decreased food intake (due to reduced hunger and increased satiety, food intolerances, frequent vomiting); 3) inadequate nutrient supplementation (due to poor compliance with multivitamin/multimineral regimen, insufficient amounts of vitamins and/or minerals in supplements); 4) nutrient malabsorption; and 5) inadequate nutritional support (due to lack of follow-up, insufficient monitoring, difficulty in recognizing symptoms of deficiency). For some nutrients (e.g., protein, vitamin B-12, vitamin D), malnutrition issues are reasonably addressed through patient education, routine monitoring, and effective treatment strategies. However, there is little attention paid to other nutrients (e.g., zinc, copper), which if left untreated may have devastating consequences (e.g., hair loss, poor immunity, anemia, defects in neuro-muscular function). This review focuses on malnutrition in essential minerals, including calcium (and vitamin D), iron, zinc, and copper, which commonly occur following popular bariatric procedures. There will be emphasis on the complexities, including confounding factors, related to screening, recognition of symptoms, and, when available, current recommendations for treatment. There is an exceptionally high risk of malnutrition in adolescents and pregnant women and their fetuses, who may be vulnerable to problems in growth and development. More research is required to inform evidence-based recommendations for improving nutritional status following bariatric surgery and optimizing weight loss, metabolic, and nutritional outcomes.

Is there a relation between number of adjustments and results after gastric banding?

BACKGROUND

Laparoscopic adjustable gastric banding (LAGB) is a standard restrictive bariatric procedure. Previous studies have shown that patients lost to follow-up do worse than patients who remain in follow-up. However, it is unknown if this is purely because of a lack of band adjustments. The aim of this study was to study the relation between number of adjustments and results.

METHODS

Patients who underwent primary LAGB from October 2006 until March 2009 were included. The following parameters were collected: demographic characteristics, preoperative and postoperative weight, preoperative and postoperative status of co-morbidities, type of band, short- and long-term complications, reoperations, date, number and volume of adjustments, total amount of inserted volume, and last measured volume.

RESULTS

One hundred seventy-four patients underwent primary LAGB. Twelve patients did not attend follow-up visits after 24 months (8.1%). Mean follow-up was 46 months, and excess weight loss, 47%. Eleven patients (8.1%) developed long-term complications, and 12 patients (8.8%) underwent revisional surgery. Patients underwent a mean number of 5 adjustments with a range of 0 to 18. The mean volume of totally inserted milliliters was 8 mL, with a range of 0 to 14 mL. There was a strong positive relation between number of adjustments and weight loss as well as reduction in obesity-related co-morbidities (r = .22; P<.01). There was no significant relation between number of adjustments and complications or revisional surgery.

CONCLUSION

There is a strong relation between the number of band adjustments and weight loss, whereas complications and reoperations seem to be independent of the number of adjustments. A continual and lifelong follow-up of LAGB patients, including regular band volume adjustments, is necessary.