Digital public defence: Marius Svanevik Marius Svanevik at Institute of Clinical Medicine will be defending the thesis "Randomized controlled trial of standard versus distal Roux-en-Y gastric bypass in patients with BMI 50-60 kg/m2 - Short and midterm results on weight loss, adverse events, health related quality of life, and bone health" for the degree of PhD (Philosophiae Doctor).

The public defence will be held as a video conference over Zoom.

The digital defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

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Digital trial lecture - time and place

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Adjudication committee

  • First opponent: Professor Marco Bueter, University of Zurich, Switzerland 
  • Second opponent: Professor John Roger Andersen, Western Norway University of Applied Sciences, Førde
  • Third member and chair of the evaluation committee: Professor Mette Kalager, Institute of Health and Society, University of Oslo 

Chair of defence

Associate Professor Hanne Cathrine Lie, Institute of Basic Medical Sciences, University of Oslo

Principal Supervisor

Professor II Jøran Hjelmesæth, Institute of Clinical Medicine, University of Oslo


Surgical treatment of obesity induce long-term and sustained weight loss. However, there is no consensus on the optimal procedure for patients with BMI equal to or above 50kg/m2. Roux-en-Y gastric bypass is considered the “gold standard” method, due to its safety and its long-term effects on weight loss. Other procedures such as duodenal switch induce a greater weight loss, but with higher risk. Distal gastric bypass is a variant of gastric bypass that could potentially have a greater effect without these potentially deleterious side effects.

We conducted a randomized control trial comparing the effects of standard and distal gastric bypass. Our primary hypothesis was that distal gastric bypass would lead to greater weight loss than standard gastric bypass. We found that operating time was longer with distal gastric bypass, and the frequency of severe complications requiring reoperation was higher. There was no significant difference in the amount of weight or BMI loss two years after surgery. There were some beneficial outcomes on cardiometabolic risk factors after distal RYGB, but the frequency of secondary hyperparathyroidism was higher.

Distal gastric bypass had no advantage over standard gastric bypass in terms of improvements in generic or obesity specific quality of life. Bone turnover was increased after both procedures, with no significant differences.

The implication of the thesis is that when balancing the risks and benefits, the evidence favors the standard gastric bypass, which continues to be our standard procedure for this patient group, this variant of distal gastric bypass should be abandoned as a procedure in these patients.

Additional information

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Published Aug. 28, 2020 12:18 PM - Last modified Sep. 14, 2020 10:10 AM