Malnutrition is one of the most feared complication of the duodenal switch operation. It may present years after surgery. What is common is a mix of nutritional deficiencies which include fat soluble vitamins, and protein calorie malnutrition. These all point to possible excessive shortening of the common channel. In my practice we have seen patients that have had lengthening of their common channel to improve their metabolic picture. What is very obvious to us, is that we see disproportionately higher number of cases coming to us for revision from practices where the common and alimentary lengths are done as a “standard” numbers with no specific adjustments made for the patient, their anatomy and situation. I have said for years, that the length of the bowel that is measured to be become the common and the alimentary limb should be a percentage of the total length of small bowel, rather than a pre-determined measurement. Here is a visual description of how this works.

If a common channel and the alimentary limb is measured to be a percent of the total length then the chance of protein calorie malnutrition is minimized since this will take into account the bowels absorptive capacity which is being reduced. This decrease in the absorption is done as a fraction of the total length.

Raines et al. published  a study in 2014, that showed how small bowel length is related more closely to a patient’s height and not weight.  And yet, some surgeons totally based the length of the common channel and the alimentary limb arbitrarily based on the patient pre operative BMI and nothing else. Could this be the cause of why I see some patients coming to us for revision of their duodenal switch for malnutrition?