SAPI vs SASI in the Management of Morbid Obesity

Single Anastomosis Plication Ileal Bypass Versus Single Anastomosis Sleeve Ileal Bypass in the Management of Morbid Obesity, a Comparative Study

Study Design A single-center cohort study combining prospective and retrospective data collection was conducted. The prospective arm enrolled consecutively admitted patients, while the retrospective arm analyzed previously recorded cases meeting identical eligibility criteria.

Study Setting and Population

The study was performed at the General Surgery Department, Faculty of Medicine, Mansoura University. It included adults aged 18-65 years with morbid obesity eligible for bariatric surgery:

• BMI ≥ 40 kg/m², or
• BMI ≥ 35 kg/m² with obesity-related comorbidities, or
• BMI 30-34.9 kg/m² with at least one major comorbidity (e.g., T2DM, hypertension, OSA, dyslipidemia, osteoarthritis) Study Period
• Prospective: September 2021 - September 2023
• Retrospective: January 2017 - August 2021 Eligibility Criteria Included patients were ASA I-III and had failed structured non-surgical weight management for ≥6 months.

Exclusion criteria included endocrine obesity, prior bariatric surgery, severe psychiatric or cognitive disorders, substance abuse, pregnancy, and previous major upper abdominal surgery.

Sample Size

Sample size was calculated based on cost difference between SASI and SAPI procedures using a two-sample means formula. A clinically relevant difference of 500 USD and SD of 700 USD were assumed, yielding:

• 31 patients per group (62 total)
• Adjusted for 10% attrition → 70 total patients Final allocation was approximately 2:1 (SASI:SAPI), reflecting real-world recruitment rather than randomization.

Group Allocation Non-randomized assignment was used. Prospective allocation involved shared decision-making within a multidisciplinary team, while retrospective allocation was based on prior surgical records. Influencing factors included cost, availability, insurance, and patient preference.

________________________________________ Methods Preoperative Assessment

Comprehensive evaluation included:

• Detailed medical history and comorbidity assessment
• Nutritional deficiency screening and correction
• Anthropometric measurements (BMI, WHR, IBW, EBW)
• Laboratory tests (CBC, liver/renal function, lipid profile, glucose, thyroid, coagulation)
• Imaging: ultrasound, PFTs, echocardiography, endoscopy, sleep studies (as indicated) Validated Questionnaires
• Physical activity: RAPA
• Eating behavior: SREB-Q and EAT-26
• Sleep quality: PSQI
• Socioeconomic status: Fahmy & El-Sherbini scale
• Quality of life: MAQ-II

Surgical Procedures

Two laparoscopic techniques were performed:

SAPI

• Gastric devascularization and plication over a 36-Fr bougie
• 300 cm isoperistaltic ileal loop anastomosed to gastric antrum
• Side-to-side stapled gastroileal anastomosis with double-layer closure SASI
• Sleeve gastrectomy over 36-Fr bougie
• 300 cm ileal loop anastomosed to gastric antrum
• Stapled gastroileal anastomosis with double-layer closure Both procedures included leak testing, drain placement, and dual-outlet gastric configuration.

Postoperative Management

Standardized enhanced recovery protocol:

• Early mobilization and VTE prophylaxis (LMWH + compression stockings)
• Proton pump inhibitors and analgesia
• Gradual oral intake from postoperative day 1
• Routine imaging and lab assessment when indicated
• Early discharge on day 2 if stable

Cost Analysis

A micro-costing approach was used, including:

• Primary costs: technology, personnel, instruments, disposables, hospitalization, follow-up, supplements
• Secondary costs: readmissions and re-interventions

Cost components were calculated using standardized formulas for:

• Equipment depreciation
• Staff time allocation
• Consumables per procedure
• Hospital stay and follow-up utilization Total cost = Primary + Secondary costs

Cost-effectiveness was evaluated using:

• Cost-effectiveness ratios (CER)
• Incremental cost-effectiveness ratio (ICER)
• Outcomes included %EWL, complication rates, comorbidity remission, and BAROS score.

Follow-Up and Outcomes

Follow-up included:

• Weekly (1st month), biweekly (next 2 months), then quarterly (up to 1 year)
• Assessment of weight loss, comorbidities, complications, and QoL

Primary outcome:

• Total cost difference between SASI and SAPI

Secondary outcomes:

• Operative time, hospital stay, complications
• %EWL, comorbidity remission (T2DM, HTN, OSA, GERD, dyslipidemia)
• QoL (MAQ-II, BAROS)

Statistical Analysis

Performed using SPSS v26:

• Normality: Shapiro-Wilk test
• Continuous data: t-test or Mann-Whitney U
• Categorical data: Chi-square or Fisher's test
• Regression: linear and logistic models
• Significance set at p < 0.05.

Ethics

• IRB approval obtained (MD.21.03.433)
• Conducted per Declaration of Helsinki and STROBE guidelines
• Written informed conse

Study Overview

• Status: Completed
• Conditions: Morbid Obesity Requiring Bariatric Surgery
• Intervention / Treatment: Procedure: Single Anastomosis Sleeve Ileal (SASI) Bypass Procedure; Procedure: Single Anastomosis Plication Ileal (SAPI) Bypass Procedure

Detailed Description

9. PATIENTS 9.1 Study Design This investigation was designed as a single-center cohort study integrating both prospective and retrospective data collection to enhance sample size and improve generalizability while maintaining methodological consistency.

• The prospective arm involved real-time, consecutive enrollment of eligible patients undergoing bariatric surgery, with standardized perioperative and follow-up data collection.
• The retrospective arm included analysis of previously recorded cases from institutional databases, provided they met identical inclusion and exclusion criteria and followed the same perioperative protocols.

Both cohorts were analyzed using unified definitions, outcome measures, and follow-up schedules to ensure comparability between groups.

________________________________________ 9.2 Study Setting The study was conducted at the General Surgery Department, Faculty of Medicine, Mansoura University, a tertiary referral center with expertise in metabolic and bariatric surgery.

The target population included patients with morbid obesity eligible for metabolic intervention, defined according to internationally accepted criteria:

• BMI ≥ 40 kg/m², OR
• BMI ≥ 35 kg/m² with at least one obesity-related comorbidity
• BMI 30-34.9 kg/m² only in the presence of significant comorbidity (e.g., type 2 diabetes mellitus, hypertension, obstructive sleep apnea, dyslipidemia, or osteoarthritis)

9.3 Study Period

The study spanned two phases:

• Prospective phase: September 2021 - September 2023
• Retrospective phase: January 2017 - August 2021 Both phases used identical eligibility criteria, perioperative protocols, and outcome definitions.

9.4 Eligibility Criteria Inclusion Criteria

Patients were included if they:

• Were aged 18-65 years
• Had ASA physical status I-III
• Were diagnosed with morbid obesity meeting BMI criteria
• Had failed structured non-surgical weight management for at least 6 months
• Underwent multidisciplinary preoperative evaluation including dietary, behavioral, and lifestyle interventions The non-surgical program included dietary restriction, behavioral counseling, and supervised lifestyle modification.

Exclusion Criteria

Patients were excluded if they had:

• Secondary obesity due to endocrine disorders (e.g., Cushing's syndrome)
• Prior bariatric or metabolic surgery
• Severe psychiatric illness or cognitive impairment affecting consent or adherence
• Active substance abuse or alcoholism
• Pregnancy or planned pregnancy within 12 months
• Previous major upper abdominal surgery potentially altering anatomy or increasing surgical risk
• Poor compliance or unwillingness to adhere to long-term follow-up and lifestyle changes

9.5 Sample Size Calculation Sample size estimation was performed using an online statistical calculator (clincalc.com) based on the primary endpoint: total cost difference between SASI and SAPI procedures.

Assumptions:

• Expected cost difference: 750-900 USD (based on Elbanna et al., 2020)
• Conservative minimum clinically significant difference (Δ): 500 USD
• Standard deviation (σ): 700 USD
• Power: 80%
• Alpha: 0.05

Formula-based calculation:

For comparison of two independent means, the required sample size was calculated using standard statistical methods.

Results:

• Required sample per group: 31 patients
• Total required sample: 62 patients
• Adjusted for 10% dropout: ~70 patients Final recruitment ranged between 62-70 patients, depending on follow-up completeness. The final distribution was approximately 2:1 (SASI:SAPI) due to natural clinical selection patterns rather than predetermined randomization.

9.6 Group Allocation This was a non-randomized cohort allocation study.

Prospective phase:

Allocation was based on shared decision-making, involving:

• Bariatric surgeon
• Metabolic physician
• Dietitian
• Psychiatrist
• Patient preference

Retrospective phase:

Patients were assigned based on previously performed procedures documented in medical records.

Influencing factors:

• Procedure cost differences
• Resource availability
• Insurance coverage
• Patient preference and awareness

• Institutional experience The observed predominance of SASI procedures reflected higher patient acceptance and demand rather than bias in eligibility or surgical capability.

  10. METHODS

10.1 Preoperative Evaluation 10.1.1 Clinical History

A detailed history was obtained, including:

• Etiology and duration of obesity
• Presence and progression of comorbidities
• Medication history (including weight-promoting drugs)
• Family history of obesity
• Previous weight loss attempts (medical or surgical)
• Comorbidity progression timeline
• Nutritional deficiency risk assessment
• Menstrual history in female patients

10.1.2 Nutritional Assessment

Routine screening identified common deficiencies:

• Vitamin D
• Iron
• Vitamin B12
• Folate
• Zinc Deficiencies were corrected preoperatively to optimize surgical safety and recovery.

10.2 Anthropometric and Clinical Examination Clinical Examination

Comprehensive systemic evaluation included:

• Cardiovascular, respiratory, hepatic, endocrine assessment
• Detection of occult malignancy
• Psychiatric and functional evaluation
• Abdominal examination for scars and hernias
• Musculoskeletal functional status assessment

Anthropometric Measurements

Standardized measurements included:

• Height and weight
• BMI calculation (kg/m²)
• Waist and hip circumference
• Waist-to-hip ratio
• Ideal body weight (IBW = 25 × height²)
• Excess body weight (EBW = actual weight - IBW)

10.3 Laboratory and Imaging Workup Routine Investigations

• CBC
• Liver function tests
• Renal function tests
• Coagulation profile
• Fasting and postprandial glucose
• Lipid profile
• Thyroid function tests
• Hormonal assays (when indicated)

Imaging and Functional Tests

• Abdominal ultrasound
• Pulmonary function tests
• Echocardiography (selected patients)
• Upper GI endoscopy / barium studies
• Sleep studies (suspected OSA)
• HbA1c and vitamin levels

10.4 Preoperative Optimization Medical Optimization

• Stabilization of comorbidities
• Cardiopulmonary optimization
• Endocrine control

Medication Adjustment

• Anticoagulants and antiplatelets adjusted
• Antihypertensive and antidiabetic drugs modified
• Coordination with relevant specialties ensured

Preoperative Counseling

Patients were informed regarding:

• Surgical steps and mechanisms
• Risks and complications
• Need for lifelong lifestyle modification
• Importance of follow-up adherence Informed written consent was obtained.

Lifestyle Preparation

• Very low-calorie diet (800-1000 kcal/day) for 2-6 weeks
• Smoking cessation for ≥6 weeks
• Preoperative weight reduction and liver shrinkage

Comorbidity Optimization

• Diabetes: HbA1c target 7-8%
• Dyslipidemia: managed per NCEP ATP III guidelines
• Hypertension: optimized pharmacologically

Perioperative Prophylaxis

• VTE prophylaxis: LMWH + compression stockings
• Antibiotics: IV cephalosporin pre-incision
• Analgesia: multimodal pain control
• Gastric protection: PPI administration ________________________________________ 10.5 SURGICAL PROCEDURES Both procedures were performed laparoscopically under general anesthesia in reverse Trendelenburg position.

10.5.1 SAPI Procedure

Key steps:

• Gastric devascularization
• Gastric plication over 36-Fr bougie
• Two-layer suturing technique
• Measurement of 300 cm ileal limb
• Isoperistaltic gastroileal anastomosis
• Stapled anastomosis with barbed suture closure

10.5.2 SASI Procedure

Key steps:

• Sleeve gastrectomy over 36-Fr bougie
• Preservation of pyloric region
• 300 cm ileal limb anastomosis
• Stapled gastroileal connection
• Reinforced double-layer closure

Intraoperative Protocol

• Methylene blue leak test
• Drain placement
• Dual-outlet gastric configuration
• Ensuring hemostasis and integrity

10.6 POSTOPERATIVE CARE General Management

• ICU admission for high-risk patients
• Proton pump inhibitor therapy
• WHO-based analgesia protocol
• Antiemetic therapy

VTE Prevention

• Early mobilization
• Compression stockings
• Extended LMWH prophylaxis (7-14 days or longer if needed)

Nutrition

• Clear fluids day 1
• Gradual diet advancement

Monitoring

• Gastrografin study when indicated
• CBC monitoring for complications
• Glycemic control adjustments

Discharge Criteria

• Stable vital signs
• Pain score <3
• No vomiting or bleeding
• No early complications
• Typically discharged on postoperative day 2

10.7 COST ANALYSIS A detailed micro-costing approach was used. Primary Costs

Included:

• Technology (capital equipment depreciation)
• Personnel costs
• Reusable instruments
• Disposables
• Hospital stay
• Follow-up visits
• Nutritional supplements

Secondary Costs

Included:

• Readmissions
• Re-interventions
• Complication management ________________________________________ Cost Framework Total Cost = Primary Costs + Secondary Costs

Cost-Effectiveness Analysis

Evaluated using:

• CER (Cost-Effectiveness Ratio)
• ICER (Incremental Cost-Effectiveness Ratio)

Outcomes:

• %EWL
• Complication rates
• Comorbidity remission
• BAROS score

10.8 FOLLOW-UP

Structured follow-up schedule:

• Weekly (first month)
• Biweekly (next 2 months)
• Quarterly (up to 12 months)

Assessments Included

• Weight, BMI, %EWL
• Comorbidity status
• Complications (Clavien-Dindo classification)
• Nutritional status
• QoL (MAQ-II, BAROS)

Outcome Definitions (ASMBS-based)

• T2DM remission: HbA1c <6% without medication
• HTN remission: normotension without drugs
• Dyslipidemia remission: normal lipid profile
• OSA resolution: AHI <5 without CPAP
• GERD resolution: symptom + pH normalization

10.9 STATISTICAL ANALYSIS

Performed using SPSS v26:

• Normality: Shapiro-Wilk test
• Continuous variables: t-test / Mann-Whitney U
• Categorical variables: Chi-square / Fisher exact
• Regression: logistic and linear models Significance threshold: p < 0.05 (two-tailed).

10.10 ETHICAL CONSIDERATIONS

• IRB approval obtained (MD.21.03.433)
• Conducted according to Declaration of Helsinki
• STROBE reporting compliance
• Written informed consent obtained
• Data anonymization ensured
• No external funding or conflicts of interest

• Study Type: Interventional
• Enrollment (Actual): 68
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • Al Mansurah, Egypt
    • Mansoura University Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age between 18 and 65 years
• Classified as American Society of Anesthesiologists (ASA) physical status I-III
• Diagnosed with morbid obesity
• Failure to achieve or maintain clinically significant weight loss after ≥6 months of structured, supervised non-surgical weight management
• Participation in a supervised program including dietary modification, behavioral counseling, and lifestyle interventions

Exclusion Criteria:

• Obesity secondary to endocrine disorders (e.g., Cushing's syndrome)
• Previous bariatric or metabolic surgery
• Significant cognitive impairment affecting consent or follow-up
• Major psychiatric illness interfering with adherence or postoperative care
• Active substance abuse or alcoholism
• Pregnancy at enrollment or planned pregnancy within 12 months
• Previous major upper abdominal laparotomy affecting surgical anatomy or increasing operative risk
• Poor motivation or unwillingness to comply with long-term lifestyle modification and follow-up

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: SASI Procedure Group; Patients undergo sleeve gastrectomy combined with omega-loop ileal anastomosis (300 cm from ileocecal valve), according to standardized surgical protocol	Procedure: Single Anastomosis Sleeve Ileal (SASI) Bypass Procedure; Participants undergo laparoscopic SASI bariatric surgery consisting of sleeve gastrectomy followed by a single omega-loop gastroileal anastomosis. An isoperistaltic ileal limb is measured 300 cm proximal to the ileocecal valve. A stapled side-to-side gastroileal anastomosis is created, and the staple entry site is closed with barbed sutures. Standard leak testing and drain placement are performed.
Active Comparator: SAPI Procedure Group; Patients undergo gastric plication with omega-loop ileal anastomosis (300 cm from ileocecal valve), following standardized technique	Procedure: Single Anastomosis Plication Ileal (SAPI) Bypass Procedure; Participants undergo laparoscopic SAPI bariatric surgery involving gastric plication followed by a single omega-loop gastroileal anastomosis. An isoperistaltic ileal limb is measured 300 cm from the ileocecal valve. A stapled side-to-side anastomosis is performed between the gastric antrum and ileal loop, with closure of the enterotomy using barbed sutures. Leak testing and drain placement are routinely performed.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total Cost of Surgical Management (SASI vs SAPI)	Comparison of the total economic burden associated with SASI and SAPI procedures, including all direct medical costs from index admission and subsequent follow-up.	Up to 12 months postoperatively

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Operative Time	Duration of surgical procedure from incision to closure	Intraoperative
Length of Hospital Stay	Duration of postoperative hospitalization	From surgery to discharge (up to 30 days)
Postoperative Complications	Incidence and severity of complications	Up to 12 months postoperatively
Percentage Excess Weight Loss (%EWL)	Change in excess body weight relative to ideal body weight	Baseline, 6 months, 12 months
Body Mass Index (BMI)	Change in BMI over follow-up period	Baseline, 6 months, 12 months
Remission of Obesity-Related Comorbidities	Rate of remission or improvement of obesity-related comorbidities	up to 12 months postoperatively
Quality of Life (MAQ-II Score)	Health-related quality of life assessed using Moorehead-Ardelt Questionnaire II	Baseline, 12 months
Bariatric Outcomes (BAROS Score)	Composite bariatric outcome score integrating weight loss, comorbidities, complications, and QoL	at 12 months postoperatively
Cost-Effectiveness Outcomes	Cost-effectiveness ratio (CER) and incremental cost-effectiveness ratio (ICER) comparing SASI vs SAPI in relation to %EWL, Comorbidity remission, and BAROS score	at 12 months postoperatively

Collaborators and Investigators

• Sponsor: Mansoura University

Study record dates

Study Major Dates

• Study Start (Actual): September 11, 2021
• Primary Completion (Actual): July 11, 2024
• Study Completion (Actual): March 15, 2025

Study Registration Dates

• First Submitted: May 24, 2026
• First Submitted That Met QC Criteria: May 24, 2026
• First Posted (Actual): June 1, 2026

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 24, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Quality of life; Bariatric surgery; Excess weight loss; Morbid obesity; Cost-effectiveness analysis; Metabolic surgery; SASI (Single Anastomosis Sleeve Ileal bypass); SAPI (Single Anastomosis Proximal Ileal bypass); Micro-costing; Obesity surgery outcomes; Comorbidity remission; BAROS score; Comparative cohort study
• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Obesity; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity, Morbid
• Other Study ID Numbers: MD.21.03.433

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No