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:
* Body mass index (BMI) ≥ 35 kg/m² with obesity-related comorbidities, or
* BMI 30-34.9 kg/m² with at least one major comorbidity \[e.g., type 2 diabetes mellitus (T2DM), hypertension (HTN), obstructive sleep apnea (OSA), dyslipidemia, osteoarthritis (OA), and gastroesophageal reflux disease (GERD)\] Study Period
* Prospective: September 2021 - September 2023
* Retrospective: January 2017 - August 2021 Eligibility Criteria Included patients were American Society of Anesthesiology (ASA) class 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:
* Total of 62 patients in the entire cohort
* Adjusted for 10% attrition → 70 total patients Final allocation was approximately 2:1 single anastomosis sleeve ileal bypass (SASI) : single anastomosis plication ileal bypass (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
* Laboratory tests
* Imaging (as indicated) Validated Questionnaires
* Physical activity: using The Rapid Assessment of Physical Activity (RAPA)
* Eating behavior: Self-Regulation of Eating Behavior Questionnaire (SREB-Q) and The Eating Attitudes Test (EAT-26)
* Sleep quality: The Pittsburgh Sleep Quality Index (PSQI)
* Socioeconomic status: Fahmy \& El-Sherbini scale
* Quality of life (QoL): The Moorehead-Ardelt Quality of Life Questionnaire II (MA-QoL II)
Surgical Procedures
Two laparoscopic techniques were performed:
SASI
* Sleeve gastrectomy over 36-Fr bougie
* 300 cm ileal loop anastomosed to gastric antrum
* Stapled side-to-side stapled gastroileal anastomosis SAPI
* Same, but gastric devascularization and plication over a 36-Fr bougie rather than sleeve gastrectomy Both procedures included leak testing, drain placement, and dual-outlet gastric configuration.
Postoperative Management
Standardized enhanced recovery protocol:
* Early mobilization and VTE prophylaxis
* Proton pump inhibitors and analgesia
* Gradual oral intake from postoperative day 1
* Imaging and lab assessment when indicated
* Early discharge 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 each item Total cost = Primary + Secondary costs
Cost-effectiveness was evaluated using:
* Cost-effectiveness ratios (CER)
* Incremental cost-effectiveness ratio (ICER)
* Outcomes included percentage of excess weight loss (%EWL), complication rates, readmission, comorbidity remission, and The Bariatric Analysis and Reporting Outcome System (BAROS).
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, length of hospital stay, complications
* %EWL, comorbidity remission
* QoL (MA-QoL 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.