Tailored Stapled SADI-S: Initial Report and Preliminary Results

Background and Rationale

With obesity rates increasing globally, metabolic and bariatric surgery (MBS) has emerged as the most effective long-term treatment for severe obesity and its related comorbidities such as type 2 diabetes mellitus, hypertension, dyslipidemia, and obstructive sleep apnea. Among the various procedures, laparoscopic sleeve gastrectomy (LSG) and Roux-en-Y gastric bypass (RYGB) have been the most frequently performed worldwide. However, the field continues to evolve with the introduction of newer, simplified techniques that aim to achieve optimal weight loss and metabolic control with lower complication rates and better nutritional safety profiles.

Single-Anastomosis Duodeno-Ileal Bypass with Sleeve Gastrectomy (SADI-S), first described by Sánchez-Pernaute and Torres in 2007, is a simplified derivative of the biliopancreatic diversion with duodenal switch (BPD-DS). This operation combines the restrictive component of sleeve gastrectomy with a single duodenoileal bypass, eliminating one anastomosis compared with the traditional DS. By preserving the pylorus, SADI-S maintains the physiological passage of food and minimizes dumping syndrome, postprandial hypoglycemia, and bile reflux.

Initially, the common channel length was set at 200 cm but was later extended to 250-300 cm to reduce the risk of excessive malabsorption and protein-calorie malnutrition. SADI-S has since demonstrated excellent outcomes in terms of weight loss, diabetes remission, and comorbidity improvement, with acceptable nutritional safety when the bypassed segment is appropriately chosen. The International Federation for the Surgery of Obesity (IFSO) and the American Society for Metabolic and Bariatric Surgery (ASMBS) have both recognized SADI-S as a validated bariatric procedure.

However, despite the growing evidence base, the optimal limb length configuration remains controversial. Most studies use fixed bypass lengths without accounting for wide interindividual variability in total small bowel length (SBL), which can range from 350 to over 1000 cm. Because SBL strongly influences caloric absorption and nutritional outcomes, a "one-size-fits-all" approach may lead to imbalanced results-either inadequate weight loss or excessive malabsorption. Measurement inconsistencies, different starting points for limb calculation, and frequent omission of total SBL assessment further complicate standardization.

Tailoring the bypass limb as a proportion of the measured total bowel length may yield more physiologically balanced results and reduce nutritional complications. Despite concerns that intraoperative measurement prolongs surgery, experienced laparoscopic surgeons can measure SBL efficiently, adding only a few minutes to operative time.

Another point of technical variation in SADI-S relates to the anastomotic technique. The duodeno-ileal anastomosis is technically more demanding than gastrojejunal anastomoses performed in RYGB or OAGB because of the thin duodenal wall and proximity to the pancreas and bile duct. While both hand-sewn and stapled techniques are described, stapled anastomosis is increasingly favored for its reproducibility, shorter operative time, and lower reported rates of leakage and stenosis.

Study Rationale

This prospective observational study aims to evaluate a tailored, stapled SADI-S technique in which the length of the biliopancreatic limb (BPL) is calculated as a fixed percentage (35%) of each patient's measured total small bowel length. By tailoring the limb to each patient's anatomy, the study seeks to optimize outcomes by achieving a balance between sufficient weight loss and nutritional safety.

To our knowledge, this is the first single-center study to systematically assess outcomes using this formula-based approach in stapled SADI-S.

Study Objectives

Primary Objective:

To evaluate the impact of bypassing approximately 35% of the measured total small bowel length on weight loss, nutritional outcomes, and postoperative symptoms in patients undergoing SADI-S (either as a primary or revisional procedure).

Secondary Objectives:

To assess the safety and practicality of using a stapled duodeno-ileal anastomosis in all patients.

To analyze correlations between the tailored BPL length and outcomes such as comorbidity remission, postoperative symptoms, and quality of life.

To assess long-term sustainability of weight loss and rates of nutritional deficiency.

Study Design

This is a prospective, single-center, observational study conducted at the Department of Surgery, El Sahel Teaching Hospital, Cairo, Egypt. The study will include 40 adult patients who meet the inclusion criteria and provide informed consent. Participants will undergo either primary SADI-S or revisional SADI-S after previous sleeve gastrectomy, depending on individual indication.

All surgeries will be performed by experienced bariatric surgeons using a standardized five-port laparoscopic approach.

Preoperative Assessment

All candidates will undergo thorough preoperative evaluation, including:

Complete medical history and physical examination.

Anthropometric measurements: height, weight, BMI.

Laboratory testing: fasting glucose, HbA1c (for diabetics), CBC, liver and renal function tests, coagulation profile, thyroid function, and micronutrient baseline panel.

Cardiopulmonary assessment with ECG and echocardiography.

Upper abdominal ultrasound to detect gallstones; concomitant cholecystectomy will be performed when indicated.

For revisional cases, CT virtual gastroscopy and gastric volumetry to assess sleeve anatomy, pouch volume, and exclude twist or stenosis.

Surgical Technique

1. Patient Positioning and Setup The operation will be performed laparoscopically using a standard five-port configuration. The patient is positioned in the French (split-leg) position with reverse Trendelenburg tilt. 2. Sleeve Gastrectomy Component

In primary cases, a 50 French bougie is used for calibration, with complete fundus mobilization and linear stapling from the antrum to the angle of His.

In revisional cases, complete adhesiolysis and pouch resizing are performed, again calibrated over a 50 French bougie. 3. Intraoperative Measurement of Small Bowel Length

The total small bowel length (TSBL) is measured from the ligament of Treitz to the ileocecal valve.

Two atraumatic bowel graspers marked at 5 and 10 cm intervals are used to measure the bowel in fully stretched segments, counting hand-by-hand.

Markings are placed at 150 cm and 200 cm with clips and sutures to facilitate later localization.

The measurement is typically completed within 8-10 minutes. 4. Tailoring of Bypass Limb

The biliopancreatic limb (BPL) is tailored to equal approximately 35% of the TSBL.

For patients with TSBL ≤ 480 cm, a fixed 300 cm common limb is retained to avoid malnutrition.

For longer TSBL, the duodeno-ileal anastomosis is created at the point corresponding to 65% of the measured total length from the ileocecal valve. 5. Duodeno-Ileal Anastomosis (Stapled Technique)

The duodenum is transected 3-4 cm distal to the pylorus using a linear stapler.

• Nutritional status and its correlation with limb length [Срок оценки: 6 months,1year, 2 years, 3 years, 4 years and 5 years]
• Safety of stapled anastomosis [Срок оценки: 6 months,1year, 2 years, 3 years, 4 years and 5 years]