One Anastomosis Gastric Bypass
One anastomosis gastric bypass (OAGB) is a weight loss surgery procedure that works by restricting the amount of food a patient can eat and reducing food absorption so patients absorb fewer calories. A modified version of Roux-en-Y gastric bypass, this procedure has shown excellent results with fewer complications for our patients at Long Island Laparoscopic Doctors.

What is One Anastomosis Gastric Bypass Surgery?
Laparoscopic one anastomosis gastric bypass surgery, or OAGB, is the most recent bariatric surgery procedure to gain approval by the American Society for Metabolic and Bariatric Surgery (ASMBS). Also known as single anastomosis gastric bypass, this procedure involves dividing the stomach to create a smaller, long gastric pouch and bypassing a portion of the small intestine so the patient is able to consume less food and absorb fewer calories.
Benefits of OAGB
- For patients who are good candidates, one anastomosis gastric bypass provides a
- Short operative time
- Low rate of complications
- Excellent outcomes

OAGB vs Roux-en-Y Gastric Bypass
One anastomosis gastric bypass is sometimes referred to as mini gastric bypass because it is a modified version of Roux-en-Y gastric bypass (RYGB).
Like traditional gastric bypass, OAGB surgery is both restrictive and malabsorptive, which means that it reduces the amount of food a patient is able to eat and it also reduces the calories absorbed by the body. Patients show similar or better weight loss after OAGB compared to gastric bypass.
For patients who are candidates, benefits of one anastomosis gastric bypass over traditional gastric bypass include:
- Less technically complex
- Lower risk of complications
-
May be a
Trusted Source One anastomosis gastric bypass vs Poublon N, Chidi I, Bethlehem M, Kuipers E, Gadiot R, Emous M, van Det M, Dunkelgrun M, Biter U, Apers J Go to Source more effective revisional bariatric surgery procedure
- Improved resolution of type 2 diabetes
- Improved resolution of hypertension
- Improved resolution of sleep apnea
It is important to note that OAGB is associated with a higher likelihood of
Trusted Source
Comparison of one-anastomosis gastric bypass and Roux-en-Y gastric bypass for treatment of obesity: a 5-year study
Bhandari M, Nautiyal HK, Kosta S, Mathur W, Fobi M
Go to Source
nutritional deficiencies
than
Trusted Source
Laparoscopic Roux-En-Y gastric bypass versus one anastomosis (loop) gastric bypass for obesity: A prospective comparative study of weight loss and complications
Mustafa A, Rizkallah NNH, Samuel N, Balupuri S
Go to Source
gastric bypass.
Candidates for OAGB
The criteria to determine candidacy for OAGB and traditional gastric bypass are similar. In general, a good candidate:
- Has a BMI above 35
- Has a BMI above 30 with obesity-related comorbidities such as type 2 diabetes.
Calculate Your Body Mass Index (BMI)
Preparing for One Anastomosis Gastric Bypass
The first step in preparing for one anastomosis gastric bypass (and any procedure performed at Long Island Laparoscopic Doctors) is to attend a consultation with one of our weight loss doctors. During this meeting, the bariatric surgeon will review the patient’s medical history, learn more about the patient’s weight loss struggles and goals, and perform an examination.
If the patient is deemed a good candidate for OAGB, the procedure will be scheduled and detailed pre- and post-operative instructions will be provided.
The OAGB Procedure
One anastomosis gastric bypass surgery is an inpatient laparoscopic procedure that is performed under general anesthesia.
To begin the procedure, the bariatric surgeon uses a laparoscopic stapler to divide the stomach, resulting in a much smaller stomach that is tube-shaped. The surgeon will then bypass up to 7 feet of the intestines, attaching the remaining portion of the intestines to the new, smaller stomach.
Recovery after Mini Gastric Bypass
After one anastomosis gastric bypass, patients recover in the hospital for one to two days. At first, the patient will only be able to consume clear liquids. Gradually, our bariatric experts will encourage the patient to slowly advance their diet by introducing first soft foods, then moving on to other foods.
As with any weight loss procedure performed by Long Island Laparoscopic Doctors, the initial recovery after OAGB is only the first step in a life-long weight loss journey. Patients are supported by our in-house nutritionist and other team members as they embrace a new, healthier lifestyle that is essential to bariatric surgery success.
Frequently Asked Questions About OAGB
Why don’t more patients choose one anastomosis gastric bypass surgery?
OAGB is has been performed internationally for the past 20 years, but is a relatively new procedure in the United States that was only recently approved by the American Society for Metabolic and Bariatric Surgery. Unlike the experts at Long Island Laparoscopic Doctors, not every bariatric surgeon has the skill, expertise, and training necessary to perform this operation. Additionally, because this procedure is only recently being performed in the United States, there isn’t enough data on it to make it eligible for coverage by many insurance carriers.
Will Insurance cover my OAGB procedure?
While OAGB weight loss surgery may be considered medically necessary, it isn’t always covered by patient’s insurance plans because it is a relatively new procedure. When you come in for your weight loss surgery consultation, we’ll help you review your plan to determine coverage. If one anastomosis gastric bypass isn’t covered by your insurance, we can help you learn more about weight loss surgery financing options.
What are the risks of one anastomosis gastric bypass surgery?
OAGB has been found to have a
Trusted Source
Efficiency and risks of one-anastomosis gastric bypass
Aleman R, Lo Menzo E, Szomstein S, Rosenthal RJ
Go to Source
lower risk profile
than traditional gastric bypass surgery. Still, there are risks and complications associated with any surgical procedure.
Risks of OAGB include:
- Leaking
- Bleeding
- Small bowel obstruction
- Dumping syndrome
- Malabsorption
- Bile reflux
Contact Us
If you are ready to begin your weight loss journey, or if you have not had success losing weight after a previous bariatric surgery procedure, please contact us to schedule a consultation with Long Island Laparoscopic Doctors.

1 Parikh M, Eisenberg D, Johnson J, El-Chaar M; American Society for Metabolic and Bariatric Surgery Clinical Issues Committee. American Society for Metabolic and Bariatric Surgery review of the literature on one-anastomosis gastric bypass. Surg Obes Relat Dis. 2018 Aug;14(8):1088-1092. doi: 10.1016/j.soard.2018.04.017. Epub 2018 May 9. PMID: 29907540. Available: https://pubmed.ncbi.nlm.nih.gov/29907540/. Accessed December 14, 2022.
2 Poublon N, Chidi I, Bethlehem M, Kuipers E, Gadiot R, Emous M, van Det M, Dunkelgrun M, Biter U, Apers J. One anastomosis gastric bypass vs. Roux-en-Y gastric bypass, remedy for insufficient weight loss and weight regain after failed restrictive bariatric surgery. Obes Surg. 2020 Sep;30(9):3287-3294. doi: 10.1007/s11695-020-04536-x. Erratum in: Obes Surg. 2020 May 8;: PMID: 32307669; PMCID: PMC7378100. Available: https://pubmed.ncbi.nlm.nih.gov/32307669/. Accessed December 14, 2022.
3 Bhandari M, Nautiyal HK, Kosta S, Mathur W, Fobi M. Comparison of one-anastomosis gastric bypass and Roux-en-Y gastric bypass for treatment of obesity: a 5-year study. Surg Obes Relat Dis. 2019 Dec;15(12):2038-2044. doi: 10.1016/j.soard.2019.05.025. Epub 2019 May 24. PMID: 31734066. Available: https://pubmed.ncbi.nlm.nih.gov/31734066/. Accessed December 14, 2022.
4 Mustafa A, Rizkallah NNH, Samuel N, Balupuri S. Laparoscopic Roux-En-Y gastric bypass versus one anastomosis (loop) gastric bypass for obesity: A prospective comparative study of weight loss and complications. Ann Med Surg (Lond). 2020 May 18;55:143-147. doi: 10.1016/j.amsu.2020.04.040. Erratum in: Ann Med Surg (Lond). 2020 Nov 18;60:701. PMID: 32477513; PMCID: PMC7251295. Available: https://pubmed.ncbi.nlm.nih.gov/32477513/. Accessed December 14, 2022.
5 Aleman R, Lo Menzo E, Szomstein S, Rosenthal RJ. Efficiency and risks of one-anastomosis gastric bypass. Ann Transl Med. 2020 Mar;8(Suppl 1):S7. doi: 10.21037/atm.2020.02.03. PMID: 32309411; PMCID: PMC7154323. Available: https://pubmed.ncbi.nlm.nih.gov/32309411/. Accessed December 14, 2022.
The doctors at Long Island Laparoscopic Doctors have either authored or reviewed and approved this content.
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