Current Organizations / Institutes

The organizations/institutes from the scholar's latest article


Marwan Emad Abdou has a total of 44 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Global Technical Variations in Roux-en-Y Gastric Bypass: A Worldwide Survey Among IFSO Members

    by Mohamed Hany, Mohamed H Zidan, Hashem Altabbaa, Ahmed Amgad, Hazem Al-Momani, Ahmed Mosaad, Aya Bessa, Fouad Hanna, Nour Zayed, Ahmed Youssef Hassan, et al.

    Background: Roux-en-Y gastric bypass (RYGB) is a widely performed metabolic and bariatric surgery (MBS) procedure with proven efficacy. However, significant variability exists in its technical execution. This study aimed to evaluate global practice patterns among surgeons affiliated with the International Federation for the Surgery and Other Therapies for Obesity (IFSO), identifying key variations and factors influencing intraoperative decision-making. Methods: A cross-sectional survey was distributed between January and November 2025 to active IFSO members performing RYGB. The survey explored techniques related to the gastric pouch configuration, intestinal limb lengths, gastrojejunostomy, ring augmentation, and adjunct use. Responses from 245 surgeons across 47 countries were analyzed using descriptive statistics, subgroup comparisons, and multivariable logistic regression. Results: Technical variability was widespread. Only 53.5% routinely measured gastric pouch length; 67.3% described their pouches as “short” or “small,” with variable anatomical endpoints. Bougie sizes ranged from 28 to 46 Fr, with 36 Fr being most common (41.2%). Only 21.6% of respondents reported routinely measuring total bowel length. Ring-augmentation was used by 20.4%, with significant regional and experiential variation. Linear stapling was preferred for gastrojejunostomy (81.2%), but stoma size and suture materials varied. Routine closure of both Petersen’s space and the jejunojejunal mesenteric defect was common (69%) yet non-uniform. High-volume surgeons had shorter hospital stays and longer follow-up, but technical patterns were similar. Conclusion: Global RYGB practice exhibits heterogeneity in several key operative steps. Improved reporting of intraoperative technical variables may help clarify which differences are most relevant to perioperative, long-term, and registry-based outcomes, and may support future consensus-building in areas where standardization is clinically justified.


  • Effect of Roux‐en‐Y Gastric Bypass and Sleeve Gastrectomy on Male Sexual Function: A Systematic Review and Meta‐Analysis

    by Mohamed Hany, Mohamed H. Zidan, Hashem Altabbaa, Ahmed El Shamarka, Marwan Emad Abdou, Mohamed Al Sayed, Bart Torensma

    Background: Obesity negatively impacts male sexual function and fertility through hormonal imbalances, endothelial dysfunction, and psychosocial factors. Metabolic and bariatric surgery (MBS) constitutes an effective intervention; however, procedure‐stratified changes in male reproductive parameters after Roux‐en‐Y gastric bypass (RYGB) and sleeve gastrectomy (SG) remain incompletely synthesized. Methodology: A systematic search of PubMed, Embase, Cochrane Library, Scopus, and Web of Science was conducted in November 2024. Sexual function, testosterone levels, and semen quality were included. Risk of bias was assessed using MINORS criteria. Random‐effects meta‐analyses were performed separately for each surgical modality, with heterogeneity quantified via I 2 statistics. Results: Twenty‐one studies comprising 848 patients were included. Meta‐analysis of pre–post data demonstrated that both RYGB and SG were independently associated with improvements in sex hormone–binding globulin and testosterone levels. In studies examining SG, significant improvements were observed in erectile function (SMD: 1.38, 95% CI: 0.66–2.10, p = 0.0002) and sperm concentration (SMD: 0.91, 95% CI: 0.56–1.26, p < 0.00001). Studies evaluating RYGB did not demonstrate statistically significant changes in erectile function (SMD: 0.62, 95% CI: −0.06 to 1.30, p = 0.07) or sperm concentration (SMD: −0.01, 95% CI: −0.45 to 0.42, p = 0.95). Conclusion: The meta‐analytical findings suggest beneficial effects of both RYGB and SG on male hormonal parameters. Studies of SG demonstrated significant improvements in erectile function and sperm concentration. However, direct comparative analyses between the two procedures were not performed, precluding definitive conclusions regarding their relative efficacy. Future research necessitates head‐to‐head comparisons with standardized reproductive endpoints and extended follow‐up periods.


  • Open Access

    Accuracy and Knowledge Base Evaluation of ChatGPT-4o, Gemini-2.0-Flash, and DeepSeek-V3 in Metabolic and Bariatric Surgery: an Expert-Rated Blinded Study

    by Mohamed Hany, Mohamed H Zidan, Chetan Parmar, Shahab Shahabi Shahmiri, Hashem Altabbaa, Ahmed El-Shamarka, Ahmed Amgad, Islam M Abdelkhalek, Abdullah A Assal, Marwan Emad Abdou, et al.

    Background: Large language models (LLMs) are increasingly applied in medicine; however, their accuracy in guideline-driven, high-stakes specialties, such as metabolic and bariatric surgery (MBS), remains uncertain. This study evaluates the performance of ChatGPT-4o, Gemini 2.0 Flash, and DeepSeek-V3 in generating guideline-concordant responses to MBS clinical questions. Methods: Thirty standardized, guideline-based MBS questions were presented to each model. Responses were randomized in order, anonymized (blinded as Model A/B/C), and evaluated by 93 MBS experts using a validated 0–3 scale (0 = inaccurate; 3 = fully guideline-concordant). A repeated-measures ANOVA with Bonferroni correction tested model differences; reliability was assessed with Cronbach’s α and intraclass correlation coefficients (ICC). Results: DeepSeek-V3 achieved the highest mean score (2.44 ± 0.40), followed by ChatGPT-4o (1.79 ± 0.46) and Gemini 2.0 Flash (1.63 ± 0.47) ( p < 0.001). Fully guideline-concordant ratings (score = 3) were most frequent for DeepSeek (80%) vs. ChatGPT (0%) and Gemini (3.3%). Internal consistency was excellent (α > 0.90), and inter-rater reliability was strong (ICC > 0.88). When mapped against the QUEST evaluation framework, the study addressed Quality and Understanding but did not fully capture Expression, Safety, or Trust dimensions. Conclusions: DeepSeek-V3 outperformed ChatGPT-4o and Gemini 2.0 Flash in generating guideline-concordant responses in MBS. These results highlight the need for ongoing, domain-focused validation before clinical use.

  • Open Access

    Post OAGB Reflux: Strengthening Evidence-Based Surveillance

    by Ahmed Talha, Aya Bessa, Zeyad Ahmed Talha, Mohamed Ragab, Marwan Abdou


  • Enhancing Understanding and Management of Obesity-Related Kidney Disease: Insights and Recommendations

    by Mohamed Mokhtar, Ahmed Gazya, Shorouk Mourad, Marwan Emad Abdou

  • Open Access

    Port Site Placement and Outcomes for Surgical Obesity and Metabolic Surgeries (PSPOSO) Checklist: A New Reporting Checklist Based on Evidential Assessment of the Number of Trocars and Positions

    by Mohamed H. Zidan, Hassan El-Masry, Ahmed Amgad, Hashem Altabbaa, Marwan Emad Abdou, Samar A. Amer, Nour Zayed, Haidy Osama Ismail, Mohammed Alokl, Ahmed Abokhozima

    Since the early 1980s, efforts to standardize ergonomic practices in laparoscopic surgeries have aimed to improve procedural efficiency and reduce complications, but clinical validation remains limited. In metabolic and bariatric surgeries (MBS), innovations in trocar site placements, driven by the popularity of laparoscopic sleeve gastrectomy (LSG), have advanced surgical techniques. However, practices often vary based on individual surgeon preferences rather than standardized evidence-based criteria. This study introduces the Port Site Placement and Outcomes for Surgical Obesity and Metabolic Surgeries (PSPOSO) checklist, aiming to standardize port placements and improve reporting consistency. A systematic review and meta-analysis of LSG studies were conducted following PRISMA guidelines. Data were extracted from 34 studies involving 7173 cases. Key variables included port configurations, manipulation angles, and outcomes such as operative time and excess weight loss percentage (EWL%). Innovative methods were used to estimate manipulation and azimuth angles from available intraoperative images. Statistical analyses and meta-regression were performed to identify associations between port configurations and surgical outcomes. Findings revealed substantial variability in port placements, with no significant effect of manipulation angles or port numbers on operative time or EWL% at 6, 12, and 24 months (p-values > 0.05). High residual heterogeneity suggests that factors beyond manipulation angles and port counts contribute to outcome variability. The PSPOSO checklist provides a framework for standardizing port placement and ergonomic parameters in MBS, enhancing reproducibility and safety. Future studies should validate the checklist across diverse clinical settings to refine surgical approaches and improve patient outcomes. PROSPERO: CRD42024598674.