LAUSR

Dear Editor, I wish to highlight an important issue facing practitioners of one anastomosis (Mini) gastric bypass (OAGB/MGB). Hardly a month goes by when I do not hear of a patient in some part of the world suffering protein-calorie malnutrition following this procedure. Though most of these patients have a biliopancreatic limb (BPL) of >200 cm, some surgeons have reportedly needed to reverse patients with BPL between 170 and 200 cm too. Evenmore surprisingly, many of these patients have become malnourished despite many meters of common channel emphasising unpredictable nature of the relationship. This complication is also highlighted in published literature on this procedure [1, 2] and yet it should be an entirely avoidable complication. The problem, in my opinion, arises from our complete lack of appreciation of how our procedures, and gastric bypass in particular, work. This leads some surgeons to use longer lengths of BPL to maximise weight loss with OAGB/MGB. Contrary to the popular belief, success after both Roux-en-Y gastric bypass (RYGB) and OAGB/MGB is not due to Brestriction and malabsorption^ [3]. We are only just beginning to understand that long-term suppression of appetite is perhaps the most important physiological effect underlying the success achieved with gastric bypass [4, 5] and though OAGB/MGB, or indeed even RYGB, can be turned into operations that result in proteincalorie malnutrition from significant malabsorption; this effect is neither necessary for majority of their effect nor desirable. One only needs to look at the evolution of limb lengths with RYGB [6] to understand this. It would appear that bypass of most of Jejunum from the passage of food is largely responsible for most of the beneficial neuro-hormonal effects observed with both OAGB/ MGB and RYGB, and our efforts hence only need to concentrate on finding out that length of Jejunum, which when bypassed, would maximise the benefits of these operations. In our detailed review [6] of limb lengths with RYGB, we found that most of the beneficial effects of RYGB are observed with a combined alimentary limb (AL) and biliopancreatic limb (BPL) length of 150 cm. Given that bypassing small intestine as BPL limb seems more effective in terms of weight loss in comparison with bypassing it as AL [7], and that OAGB/MGB bypasses all of it as BPL, one could extrapolate that the optimum length of BPL with OAGB/MGB should be no longer than 150 cm, and probably even shorter. This is in fact now being noticed by several groups of OAGB/MGB surgeons, including ours. All bariatric procedures are associated with excessive weight loss or malnutrition in some patients. Though causes and solution of this particular problem can vary from procedure to procedure, the search for a procedure that can deliver an Bideal^ weight loss outcome for all patients has so far proved elusive as has our ability to titrate our procedures to the goals of an individual patient. Just like distal versions of RYGB [6] were associated with a slightly higher weight loss but significantly higher incidence of protein-calorie malnutrition, distal versions of OAGB/MGB are also associated with a definite malnutrition rate and since all of the bypassed small bowel is placed as BPL, effect on absorption of nutrients is even more unpredictable. Furthermore, weight loss from malabsorption has not proved to be a desirable commodity. Declining worldwide use of procedures that result in significant malabsorption [8] should confirm this as should the fact that very few surgeons today would perform distal versions of the RYGB. * Kamal K. Mahawar [email protected]