OAGB: The Mini Gastric Bypass

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One anastomosis gastric bypass (OAGB), also known as the mini gastric bypass, is a bariatric surgery that is both shorter and simpler than standard gastric bypass. The aim of the procedure is to improve the quality of life and future health  in overweight patients. The mini gastric bypass was first developed over 20 years ago to overcome operative difficulties and risks of the Roux-en-Y gastric bypass (RYGB). Although the RYGB procedure is one of the most commonly performed bariatric surgeries in the United States, the mini gastric bypass is another surgery that delivers excellent outcomes with low rates of perioperative complications in suitable candidates. (1) 

To book a bariatric surgery consultation, and to find out more about the OAGB mini gastric bypass procedure, get in touch with Texas Endosurgery. Ricardo Bonnor M.D., FACS, FASMBS is a leading robotic surgeon specializing in weight loss surgery. Located in Houston, Texas, call us directly at (281) 579-5638 or fill out our simple inquiry form to schedule your appointment.

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About the Mini Gastric Bypass

The OAGB is one of several surgical procedures a patient can undergo to lose weight. Though the surgery is commonly referred to as a mini gastric bypass, it is also known as the omega-loop bypass or single anastomosis gastric bypass (SAGB). Diet, lifestyle choices, and underlying health conditions can all affect our weight, but for men and women with a body mass index (BMI) of over 40, the risk of developing weight-related health conditions is higher. Common obesity-related diseases in the United States include the following.

  • Type 2 Diabetes 
  • Hypertension (High Blood Pressure) 
  • Dyslipidemia (An Imbalance of Fatty Acids)
  • Obstructive Sleep Apnea
  • Non-Alcoholic Fatty Liver Disease
  • Gallbladder Disease (2)(3)

With bariatric surgery, achieving a better quality of life, while maintaining reduced weight years after surgery is vital in determining its success.

How is the Mini Gastric Bypass Different?

The most common form of gastric bypass surgery in the United States is the RYGB. The mini gastric bypass is an alternative surgery with several key differences. 

An anastomosis is a connection between tubes. In a bariatric procedure, an anastomosis can be created surgically in the gastrointestinal tract. The “one anastomosis” refers to the fact that there is a single connection of the gastrointestinal tract. The key difference in the mini bypass is the “single anastomosis”, compared with the two anastomoses of RYGB. Moreover, there is a difference in the shape of the stomach. After a RYGB, the stomach is reduced to a smaller “pouch” that limits food intake, whereas in a mini gastric bypass, there is no pouch, but rather a long, sleeve-like construction of the stomach.

Although the mini gastric bypass is more popular outside of the United States, it is gaining recognition, partly due to the fact that it is a less complex surgery to perform, but also because it produces effective results for patients. Research indicates that OAGB surgeries are short and simple procedures with different complications compared to gastric bypass. (4)(5)

Note that the one anastomosis bypass has gained popularity outside the United States because it is simpler and removes the risk of bowel obstruction as compared to standard bypass. The issue with OAGB is bile reflux which may need revision surgery. The standard bypass treats reflux.

Benefits of a Mini Gastric Bypass

  • Shorter operative time
  • Minimally-invasive
  • Less complex surgical procedure
  • Low complication rate
  • Excellent weight loss outcomes
  • Improvement of obesity-related comorbidities has granted it the role of a 
  • A viable alternative to RYGB (6)

The mini gastric bypass is considered a low-failure bariatric procedure. In addition, it can be easily revised, reversed, or sleeved where necessary because it only has one anastomosis. (1) In the event that your OAGB is not successful, Dr. Bonnor offers gastric bypass revision, robotic gastric bypass revision, and robotic re-sleeving procedures.

Who is Eligible for a Mini Gastric Bypass?

There are no absolute contraindications for bariatric surgery. In most cases, patients with a BMI of over 40 will automatically be considered, as will patients with a BMI greater than, or equal to 30 with one or more obesity-related conditions. (7) To find out if you’re eligible, book a personal consultation at Texas Endosurgery.


Prior to your procedure, we will provide detailed instructions to prepare for your surgery date. A mini gastric bypass procedure is performed laparoscopically or robotically.  A long, thin gastric pouch is created excluding the body of the stomach. After this, Dr. Bonnor identifies the Treitz ligament, the connective tissue that links the duodenum (the first part of the small intestine) with the beginning of the jejunum (the middle part of the small intestine). From here, he determines the correct length to segment the food pathway. He then links the duodenum with the long “pouch” using a vertical, or slightly angled “omega loop”. He then staples and sutures this section. Finally, the small incisions made for the trocars are closed. (8)

Mini Gastric Bypass in Houston, TX

If you’re tired of weight-related health problems, and they are negatively affecting your quality of life, please get in touch. To set up your initial appointment with Dr. Bonnor, please call (281) 579-5638 or contact us online.

For more information about the benefits of bariatric surgery, find Dr. Bonnor and many of his satisfied patients on Instagram.


  1. Noun R, Skaff J, Riachi E, Daher R, Antoun NA, Nasr M. One Thousand Consecutive Mini-Gastric Bypass: Short- and Long-term Outcome. Obesity Surgery. 2012;22(5):697-703. doi:10.1007/s11695-012-0618-z https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5793145/ 
  2. Campanelli M, Bianciardi E, Benavoli D, Bagaglini G, Lisi G, Gentileschi P. Laparoscopic Banded One Anastomosis Gastric Bypass: A Single-Center Series. Papadia FS, ed. Journal of Obesity. 2022;2022:1-6. doi:10.1155/2022/4942052 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8817855/ 
  3. Ioannis Kyrou, Randeva, H. S., Constantine Tsigos, Grigorios Kaltsas, & Weickert, M. O. (2018, January 11). Clinical Problems Caused by Obesity. Nih.gov; MDText.com, Inc. https://www.ncbi.nlm.nih.gov/books/NBK278973/ 
  4. BRAGHETTO I, CSENDES A. SINGLE ANASTOMOSIS GASTRIC BYPASS (ONE ANASTOMOSIS GASTRIC BYPASS OR MINI GASTRIC BYPASS): THE EXPERIENCE WITH BILLROTH II MUST BE CONSIDERED AND IS A CHALLENGE FOR THE NEXT YEARS. ABCD Arquivos Brasileiros de Cirurgia Digestiva (São Paulo). 2017;30(4):267-271. doi:10.1590/0102-6720201700040010 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5793146/ 
  5. Rutledge R, Kular K, Manchanda N. The Mini-Gastric Bypass original technique. International Journal of Surgery (London, England). 2019;61:38-41. doi:10.1016/j.ijsu.2018.10.042 https://www.sciencedirect.com/science/article/pii/S1743919118316881?via%3Dihub 
  6. Aleman R, Menzo EL, Szomstein S, Rosenthal RJ. Efficiency and risks of one-anastomosis gastric bypass. Annals of Translational Medicine. 2020;8(S1):S7-S7. doi:10.21037/atm.2020.02.03 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7154323/ 
  7. Stahl, J. M., & Malhotra, S. (2020). Obesity Surgery Indications And Contraindications. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK513285/ 
  8. CHAIM, E. A., RAMOS, A. C., & CAZZO, E. (2017). MINI-GASTRIC BYPASS: DESCRIPTION OF THE TECHNIQUE AND PRELIMINARY RESULTS. ABCD. Arquivos Brasileiros de Cirurgia Digestiva (São Paulo), 30(4), 264–266. https://doi.org/10.1590/0102-6720201700040009