I read with great interest the study published in Surgery for Obesity and Related Diseases by DeMaria et al. It is a retrospective review of 96 gastric bypass patients who underwent conversion of to distal gastric bypass between 2010 and 2016. The Roux or alimentary limb is cut at the jejuno-jejunostomy and transposed distally leaving a common channel between 150 to 200 cm in length. The initial 11 patients developed significant diarrhea and protein malnutrition prompting the authors to lengthen the common channel by 100 to 150 cm for the rest of the patients. The mean BMI at initial gastric bypass was 48, and 41 at distalization. At one year after revision surgery Mean BMI dropped to 34 in 42 patients that followed up one year after surgery. At 2 years, BMI was 33 in 18 patients and at 3 years, BMI dropped to 32 in 10 patients. Obviously, patient follow up is a major limitation of this study. Nonetheless, there is a significant drop in excess weight at least in the short-term period following surgery.

Weight regain following gastric bypass surgery is unfortunately not infrequent. The most cause of weight regain following successful gastric bypass surgery is the resumption of processed food consumption high in simple sugars. Patients reports increased hunger, decreased restriction and low satiety levels. Laparoscopic or endoluminal procedures that narrow gastric pouch outlet or decrease its size are associated with high failure rates. After all, gastric bypass surgery is a metabolic procedure. Weight loss following gastric bypass surgery results from altered gastrointestinal neuro-hormonal signals like GLP_1 and PYY rather than mechanical restriction of gastric volume. Distalization procedures aim at bypassing damaged proximal neuroendocrine cells and target more distal cells in the ileum. Distal neuroendocrine cells are assumed to be undamaged by chronic simple sugar consumption like proximal cells. Consequently, distalization procedures can salvage a failed gastric bypass procedure by re-stimulating post-prandial GLP-1 and PYY production. Unfortunately, there are no quality studies addressing these theoretical claims to prove such an approach. It would have been quite informative if the authors of this study checked postprandial levels of GLP-1 and PYY prior to distalization and compared them to postoperative hormone levels and then correlate with weight loss outcomes. Such studies can answer important questions on patient selection and the effectiveness and reliability of revision weight loss surgery. This is equally important for sleeve gastrectomy patients. Weight regain or failure to lose weight following gastric sleeve surgery is a difficult problem to manage. Sleeve conversion to gastric bypass is associated with low morbidity and mortality but weight loss outcomes are not the best. Few studies in the literature address this issue and are limited by small sample size. Unless we understand the neurohormonal changes associated with weight loss and weight gain following metabolic surgery, and we develop reliable tools to measure these changes, revision weight loss surgery is still limited in efficacy and reliability.