Comparing Dumping Symptoms and Quality of Life 6 Months After Sleeve Gastrectomy With or Without Transit Bipartition in Adults With Obesity

Background and Rationale

Obesity has become one of the most important public-health challenges worldwide. It is associated with a wide range of comorbid conditions such as type 2 diabetes mellitus, hypertension, dyslipidemia, non-alcoholic fatty liver disease, obstructive sleep apnea, degenerative joint disease, and increased cardiovascular morbidity and mortality. Conservative management strategies-including dietary modification, physical activity, and pharmacologic therapy-often result in only modest and temporary weight reduction. Consequently, bariatric and metabolic surgery has emerged as the most effective and durable intervention for achieving long-term weight loss and improvement or remission of obesity-related diseases.

Among the different bariatric procedures, laparoscopic sleeve gastrectomy (LSG) has gained worldwide popularity. It is technically simpler than gastric bypass procedures and does not involve intestinal anastomoses or foreign materials. During LSG, approximately 75-80% of the stomach is resected along the greater curvature, leaving a tubular gastric "sleeve." This results in restrictive limitation of food intake and favorable hormonal changes, such as decreased ghrelin secretion, leading to appetite suppression. LSG has proven effective in producing substantial and durable weight loss as well as improvement in metabolic parameters.

However, despite these benefits, some patients experience functional gastrointestinal symptoms after LSG, including gastroesophageal reflux disease, food intolerance, early satiety, and dumping syndrome. Dumping syndrome refers to a collection of symptoms that occur when food passes too rapidly from the stomach into the small intestine. It can be divided into early dumping (occurring 10-30 minutes after eating, with symptoms such as nausea, abdominal cramps, palpitations, and dizziness) and late dumping (1-3 hours after eating, characterized by hypoglycemia, fatigue, and sweating). These symptoms may significantly impair quality of life (QoL), limit dietary freedom, and affect social activities.

To enhance the metabolic efficacy of sleeve gastrectomy while minimizing complications, several hybrid or modified techniques have been introduced. One such modification is sleeve gastrectomy with transit bipartition (SG-TB). In this operation, a side-to-side anastomosis is created between the distal ileum and the antrum or the first portion of the duodenum, allowing ingested food to pass through both the natural duodenal route and an alternative shortcut to the distal small intestine. This design maintains continuity of the biliary and pancreatic secretions, preserves access to the duodenum for endoscopy, and reduces the risk of nutritional deficiencies commonly seen with complete bypass procedures. Physiologically, the presence of dual intestinal transit is believed to enhance incretin hormone release (GLP-1, PYY) and improve insulin sensitivity.

Although previous studies have demonstrated that SG-TB can achieve excellent weight loss and glycemic control, comparative data regarding postoperative functional symptoms and QoL outcomes remain limited. Because dumping syndrome and related symptoms can significantly affect patient satisfaction and long-term adherence to dietary recommendations, it is essential to understand whether the addition of transit bipartition alters these outcomes relative to the standard sleeve gastrectomy.

Objectives

Primary Objective:

To compare the incidence and severity of dumping syndrome at six months after surgery between patients undergoing sleeve gastrectomy (LSG) and those undergoing sleeve gastrectomy with transit bipartition (SG-TB).

Secondary Objectives:

To compare quality of life (QoL) scores between both groups using validated QoL questionnaires specific to bariatric and gastrointestinal surgery.

To evaluate weight loss outcomes (percentage of excess weight loss, change in body mass index).

To assess improvement or remission of metabolic comorbidities (type 2 diabetes, hypertension, dyslipidemia).

To analyze nutritional and biochemical parameters (iron, vitamin B12, folate, calcium, albumin).

To record and compare postoperative complications and re-intervention rates.

Hypothesis

The study hypothesizes that adding transit bipartition to sleeve gastrectomy will reduce the frequency and/or severity of dumping syndrome by preserving a more physiologic gastric emptying mechanism and offering dual pathways for food transit. Additionally, the hormonal and metabolic benefits of SG-TB are expected to result in improved overall quality of life compared with standard sleeve gastrectomy at six months postoperatively.

Study Design

This is a prospective, comparative, single-center (or multicenter, if applicable) clinical study involving two parallel groups of adult patients undergoing bariatric surgery for the management of obesity.

Group A: Laparoscopic sleeve gastrectomy (LSG)

Group B: Laparoscopic sleeve gastrectomy with transit bipartition (SG-TB)

Patients will be evaluated preoperatively and followed for at least six months after surgery. Allocation to surgical technique will depend on preoperative multidisciplinary assessment and patient-surgeon agreement. All procedures will be performed by experienced bariatric surgeons following standardized techniques to minimize operative variability.

Study Population

Eligible participants will include adult men and women aged 18-60 years with a body mass index (BMI) ≥ 35 kg/m² with comorbidities, or ≥ 40 kg/m² regardless of comorbidities, who are candidates for bariatric surgery according to international guidelines. All participants must be willing to comply with postoperative follow-up visits and to complete the required questionnaires. Exclusion criteria (listed elsewhere in the protocol) include previous major gastric surgery, significant psychiatric illness, pregnancy, or inability to provide informed consent.

Preoperative Evaluation

Before surgery, all participants will undergo:

Full medical history and physical examination

Anthropometric measurements (weight, height, BMI, waist circumference)

Laboratory investigations (complete blood count, liver and renal function, fasting glucose, lipid profile, HbA1c, vitamins and micronutrients)

Assessment of comorbidities

Baseline quality of life assessment using standardized questionnaires (e.g., Gastrointestinal Quality of Life Index (GIQLI), Bariatric Analysis and Reporting Outcome System (BAROS), or SF-36)

Documentation of eating habits and gastrointestinal symptoms

Surgical Technique Overview

Laparoscopic Sleeve Gastrectomy (LSG):

Performed using 4-5 ports under general anesthesia. The greater curvature of the stomach is mobilized starting approximately 4-6 cm from the pylorus up to the angle of His. A 36-40 French calibration tube is used to guide gastric transection with linear staplers, creating a narrow gastric sleeve. The resected stomach is removed, and staple lines are inspected for bleeding or leakage.

Sleeve Gastrectomy with Transit Bipartition (SG-TB):

The sleeve component is created as described above. In addition, a side-to-side anastomosis is fashioned between the distal ileum (typically 250 cm from the ileocecal valve) and the antrum or first part of the duodenum, allowing a dual pathway of food transit. The mesenteric defect is closed to prevent internal herniation. This configuration aims to enhance incretin secretion and glycemic control without complete exclusion of the duodenum.

All operations will be performed laparoscopically. Standardized postoperative protocols for pain management, diet progression, and nutritional supplementation will be applied to both groups.

Postoperative Follow-Up and Assessments

Patients will be followed at regular intervals-typically at 1 month, 3 months, and 6 months postoperatively-with longer follow-up continuing as per institutional policy.

Clinical and Functional Evaluation:

Measurement of weight, BMI, and percentage of excess weight loss (%EWL)

Monitoring of vital signs and comorbid disease status

Documentation of postoperative complications (leak, bleeding, infection, bowel obstruction)

Dumping Syndrome Assessment:

At each follow-up visit, patients will be screened for dumping symptoms using a standardized questionnaire and scoring system, such as the Sigstad Diagnostic Index or Arts Dumping Score. The frequency, severity, and timing of symptoms (early vs. late dumping) will be recorded.

Quality of Life Assessment:

QoL will be evaluated preoperatively and six months postoperatively using validated instruments. Tools may include:

GIQLI (Gastrointestinal Quality of Life Index) - assessing physical, emotional, and social aspects of gastrointestinal health.

BAROS (Bariatric Analysis and Reporting Outcome System) - integrating weight loss, comorbidity resolution, and quality of life changes.

SF-36 Health Survey - measuring overall physical and mental health domains. Patients will complete these questionnaires independently, assisted by study staff if necessary.

Laboratory and Nutritional Monitoring:

Periodic laboratory tests will evaluate glycemic control (fasting glucose, HbA1c), lipid profile, liver function, and micronutrient status (iron, calcium, vitamin B12, folate, vitamin D). Nutritional counseling and supplementation will be provided as per standard bariatric guidelines.

Data Collection and Statistical Analysis

Data will be collected prospectively and entered into a secure database. Continuous variables (e.g., BMI, QoL scores) will be presented as mean ± standard deviation and compared between groups using independent-samples t-tests or Mann-Whitney U tests as appropriate. Categorical variables (e.g., presence of dumping syndrome) will be compared using chi-square or Fisher's exact tests. Within-group comparisons (pre- vs. postoperative) will use paired tests. A p-value < 0.05 will be considered statistically significant.

Multivariate analysis may be used to control for potential confounders such as age, gender, baseline BMI, and presence of diabetes. Correlations between weight loss, dumping score, and QoL improvement will also be explored.

Ethical Considerations

The study will be conducted in accordance with the Declaration of Helsinki and Good Clinical Practice (GCP) guidelines. Approval will be obtained from the local Institutional Review Board or Ethics Committee before patient enrollment. All participants will provide written informed consent after being fully informed about the purpose, procedures, potential risks, and benefits of the study. Data confidentiality and patient privacy will be maintained throughout.

Expected Outcomes and Significance

This research is expected to provide a clearer understanding of the functional and quality-of-life outcomes after two common bariatric surgical strategies. Specifically, the study aims to determine whether the addition of transit bipartition to sleeve gastrectomy reduces the incidence of dumping syndrome without compromising weight loss or safety.

If the hypothesis is confirmed, SG-TB may offer a valuable alternative for patients seeking effective metabolic results with fewer functional limitations and better postoperative comfort. Improved quality of life following bariatric surgery is a key determinant of long-term success, patient satisfaction, and adherence to healthy lifestyle changes.

Ultimately, the findings of this comparative study may assist surgeons and multidisciplinary teams in selecting the most appropriate bariatric procedure based on patient characteristics, metabolic goals, and desired postoperative quality of life.