Overview
Definition:
The Single Anastomosis Duodeno-Ileal Bypass with Sleeve (SADI-S) is a revisional or primary bariatric procedure that combines features of the sleeve gastrectomy and the duodenal switch procedure, with a single gastrointestinal anastomosis
It involves creating a sleeve gastrectomy and then performing a duodeno-ileal bypass by connecting the duodenum to a distal segment of the ileum, thereby reducing absorptive surface area
This procedure aims for significant weight loss and remission of comorbidities.
Epidemiology:
Bariatric surgery rates continue to rise globally due to the increasing prevalence of obesity and its associated metabolic diseases
SADI-S, as a relatively newer technique, is gaining traction, particularly in revisional surgery and for patients requiring more aggressive weight loss and metabolic control than achievable with simpler procedures like sleeve gastrectomy alone
Indications are typically for patients with BMI >35 kg/m² with comorbidities or BMI >40 kg/m², after failure of less invasive methods.
Clinical Significance:
SADI-S offers a powerful option for managing severe obesity and its related comorbidities like type 2 diabetes mellitus, hypertension, and dyslipidemia
Its dual mechanism of restrictive and malabsorptive effects provides significant weight loss and metabolic benefits, often surpassing those of standalone sleeve gastrectomy or gastric bypass
Understanding its indications, surgical technique, and potential complications is crucial for surgeons preparing for DNB and NEET SS examinations, as it represents an advanced bariatric intervention.
Indications
Bmi Criteria:
Generally indicated for patients with a BMI of 35-40 kg/m² with significant comorbidities, or BMI > 40 kg/m²
It is also a strong option for revisional surgery in patients who have had sleeve gastrectomy with inadequate weight loss or weight regain, or for those requiring a more potent metabolic intervention.
Comorbidities:
Type 2 diabetes mellitus (especially difficult to control), obstructive sleep apnea, hypertension, dyslipidemia, non-alcoholic steatohepatitis (NASH), osteoarthritis, and venous thromboembolism prophylaxis considerations.
Failure Of Previous Surgery:
Patients who have undergone sleeve gastrectomy and experienced insufficient weight loss (often defined as <50% excess weight loss) or significant weight regain are prime candidates for conversion to SADI-S.
Patient Selection:
Careful patient selection is paramount, involving a multidisciplinary team
Patients must be psychologically prepared, have a strong commitment to lifestyle changes, and understand the risks and long-term implications of the procedure
Endoscopic assessment for gastroesophageal reflux disease (GERD) is important, as SADI-S can exacerbate or, in some cases, improve reflux depending on the length of the common channel.
Surgical Technique
Gastric Remnant Creation:
A standard sleeve gastrectomy is performed, typically resecting 60-80% of the stomach along the greater curvature, creating a gastric tube
The pylorus is preserved.
Duodeno Ileal Anastomosis:
The duodenum is transected just distal to the pylorus
The distal ileum is then brought up to the duodenum in an antecolic, and typically antegastric, fashion to create a single duodeno-ileal anastomosis
The length of the excluded small bowel (common channel) is crucial for determining the degree of malabsorption, with lengths typically ranging from 150-250 cm
The shorter the common channel, the more pronounced the malabsorptive effect.
Anastomotic Technique:
Stapled or hand-sewn techniques can be used for the duodeno-ileal anastomosis
A one-layer or two-layer hand-sewn anastomosis may be preferred by some surgeons to minimize leak risk
Careful attention is paid to tension-free anastomosis.
Biliopancreatic Limb Creation:
The proximal end of the jejuno-ileal limb is anastomosed to the distal duodenum
The distal end of the ileal limb is then anastomosed to the gastric remnant in a side-to-side or end-to-side fashion, creating the efferent limb for biliopancreatic secretions to reach the digestive tract
This configuration creates a common channel
The length of the common channel is a critical determinant of weight loss and nutritional impact.
Postoperative Care
Fluid Management:
Intravenous fluids are initiated and gradually advanced as tolerated
Monitoring for dehydration and electrolyte imbalances is crucial, especially given the malabsorptive component.
Pain Control:
Adequate pain management with multimodal analgesia is essential for early mobilization and patient comfort
Epidural or patient-controlled analgesia (PCA) may be used.
Nutritional Support:
Patients require lifelong vitamin and mineral supplementation, including but not limited to B12, vitamin D, calcium, iron, and fat-soluble vitamins (A, E, K)
Regular monitoring of nutritional status is vital
Protein intake should be adequate.
Mobilization And Ambulation:
Early mobilization is encouraged to prevent deep vein thrombosis (DVT) and pulmonary complications
Gradual ambulation as tolerated is initiated on postoperative day 1.
Monitoring For Complications:
Close monitoring for signs of anastomotic leak, bleeding, sepsis, or bowel obstruction
Vital signs, urine output, and abdominal examinations are performed regularly
A clear liquid diet is typically started on postoperative day 1 or 2, with a gradual progression to pureed and then soft foods over several weeks.
Complications
Early Complications:
Anastomotic leak (duodeno-ileal or gastro-jejunal if performed), bleeding, intra-abdominal abscess, port site infection, deep vein thrombosis (DVT), pulmonary embolism (PE), ileus, nausea, and vomiting.
Late Complications:
Nutritional deficiencies (especially vitamin B12, iron, calcium, vitamin D), protein-calorie malnutrition, dumping syndrome (early and late), gallstones, incisional hernia, internal hernia, marginal ulceration at the anastomosis, diarrhea, steatorrhea, and gastroesophageal reflux disease (GERD) or worsening of existing GERD.
Prevention Strategies:
Meticulous surgical technique with careful attention to anastomotic integrity, use of appropriate staple lines, and prophylactic antibiotics
Early and aggressive mobilization, mechanical and pharmacological DVT prophylaxis
Thorough preoperative workup and patient education regarding dietary modifications and lifelong supplementation
Close postoperative follow-up and monitoring of nutritional markers are essential.
Prognosis
Weight Loss Outcomes:
SADI-S typically achieves excellent excess weight loss, often exceeding 70-80% at 1-2 years post-surgery
The significant malabsorptive component contributes to sustained weight loss.
Comorbidity Remission:
High rates of remission or significant improvement in comorbidities, particularly type 2 diabetes mellitus (often achieving remission in 70-90% of patients), hypertension, and dyslipidemia
This metabolic improvement is a key advantage of SADI-S.
Long Term Follow Up:
Lifelong follow-up is mandatory to monitor for nutritional deficiencies, weight stability, and potential complications
Regular blood tests to check vitamin and mineral levels, along with clinical assessments, are crucial for long-term success and patient well-being.
Factors Affecting Prognosis:
Patient adherence to lifestyle changes, dietary modifications, and lifelong supplementation
The length of the common channel, surgical technique, and management of postoperative complications also influence long-term outcomes.
Key Points
Exam Focus:
SADI-S is a complex bariatric procedure combining sleeve gastrectomy with a single-anastomosis duodeno-ileal bypass
Key features include pylorus preservation, a single anastomosis, and a variable common channel length influencing malabsorption
It offers excellent weight loss and metabolic benefits, especially for T2DM.
Clinical Pearls:
For revisional surgery after SG, SADI-S is a strong consideration for inadequate weight loss or regain
Be vigilant for nutritional deficiencies and dumping syndrome
Emphasize lifelong vitamin/mineral supplementation
The length of the common channel is the primary determinant of malabsorptive effect.
Common Mistakes:
Underestimating the risk of severe nutritional deficiencies
Inadequate management of dumping syndrome
Failure to ensure adequate common channel length for desired weight loss while balancing nutritional risks
Not recognizing or adequately managing internal hernias, a significant risk with this anatomy
Insufficient patient education on lifelong dietary and supplementation needs.