The surgical technique [23] entails the use of five trocars, placed in the positions illustrated in Fig. 20.9. The patient is placed in a moderate anti-Trendelenburg position (20–25°). As a rule, we prefer to do first the cholecystectomy, which can be annoying due to the non standard trocar positions. The gastrocolic ligament is incised at about its midpoint and the dissection, which is carried out with a harmonic scalpel, is performed until the traction of the large curve allows for the mobilization of the gastric fundus, which implies that the avascular area is always sectioned. The first short vessel is rarely sectioned, exceptionally the second. The dissection of the lower greater curve and the sectioning of the right gastroepiploic and the right gastric vessels complete the isolation of the duodenum, which is divided with single application of endoGIA 60. The small curve is then isolated cranially with the ultrasound scissors, stopping 1 or 2 cm before the trunk of the left gastric artery (Fig. 20.10), and the gastric resection is carried out by repeated firing of endoGIA 60. To measure the gastric stump is very easy by filling with water (35 cm H₂O) a condom which has been tied at the end of a nasogastric tube. Gastric volume should be measured until the surgeon becomes able to evaluate it by sight. Roughly, a gastric sectioning from the greater curve, moderately stretched, at approximately 15 cm from the cardias (Fig. 20.11) to the lesser curve at 5 cm from the cardias corresponds to a gastric volume of about 300 mL (Fig. 20.12). A distance of 20 cm along the greater curve corresponds to a volume of about 400 mL. This applies both to the laparoscopic and the open technique, as it was demonstrated by a check done in all cases of conversion (which, being due to problems with the GEA construction, was generally done after division of the stomach) at the beginning of our experience with the laparoscopic technique, when we started measuring again the gastric volume in order to reacquire the ability the gastric stump [23].

The patient is then placed in a slightly Trendelenburg position (about 10°). The small bowel is measured backward from the cecum, fully stretched (Fig. 20.3), using two forceps marked at 10 cm in alternating movements. A mark is left at 50 cm, the ileum is divided at 300 cm by using an endoGIA 45, and the mesentery is sectioned in depth with the ultrasonic scissors, taking care to proceed perpendicularly to its root (Fig. 20.13). The EEA is fashioned with a latero-lateral technique, with an endoGIA 45 through two small enterotomies made by the harmonic scalpel. The conjoined defect is closed with a manual running seromuscular suture.

The left angle of the gastric stump is then identified, grasped, and pulled into the submesocolic space through an incision performed in the transverse mesocolon over the ligament of Treitz (Fig. 20.14). The distal intestinal stump is identified, checked for possible torsion, and perforated with the ultrasonic scissors at a distance from the suture line equal to the operative length of the endoGIA 45. The latter is used to perform a latero-lateral isoperistaltic GEA on the posterior wall of the stomach, as close as possible to the distal angle and at midway between the suture line and the greater curve (Fig. 20.15), with manual closure of the conjoined defect. After the leak test with methylene blue introduced through the nasogastric tube, the GEA is anchored by two stitches to the mesocolic rent, in order to avoid intestinal kinkings and internal hernias (Fig. 20.16). We always close the distal mesenteric defect and never the proximal one (Patterson).

A liver wedge biopsy is always obtained. The last maneuver, as in open surgery, is the final intestinal check, starting from the ileocecal valve, with the surgeon following the AL and the first aid the BPL. It takes time, but it is the only way to make sure that no 360° intestinal torsion exists. As an alternative, the two mesenteric edges are carefully inspected from the anastomoses to the start of the mesenteric division.

The distal stomach, as well as the gallbladder, is extracted through the supraumbilical opening, which sometimes needs to be widened. Two drains are left in the Douglas pouch and under the liver. The trocars are removed under visual control. The fascial defect is sutured in the supraumbilical hole. The others are left as they are, with simple skin suturing.

As to the possible modifications of gastric volume and intestinal lengths, being similar all the other conditions, a larger gastric remnant generally, but not necessarily, results in a higher weight of stabilization, and certainly in a lower risk of protein malnutrition. It can be used precautionally in patients with lower compliance, never forgetting that low compliance should be considered in principle a contraindication to BPD, or in case of low BMI type 2 diabetic or hypercholesterolemic patients, when the aim of the operation is the exploitation of the specific actions for those conditions, with little or no weight loss (see below). On the contrary, a smaller gastric volume results in a more rapid weight loss with lower stabilization weight. The lower acceptable limit for gastric volume is about 300 mL (Fig. 20.12), as a smaller stomach has proven, in our [2, 18, 24] and in other authors’ experience [14], to entail a great risk of energy-protein malnutrition (PEM).

It is very important to remember that the small bowel is to be measured fully stretched, midway between the mesenteric and the antimesenteric border (Figs. 20.2 and 20.3), in order to make the measurements reproducible both in the sane and in different hands. At the beginning of our experience with laparoscopic BPD, when the conversions to open surgery were more frequent, a check of intestinal lengths measured after conversion never showed a difference greater than 10 % between the two measurements [23], so, at least in our experience, we can refer to the intestinal lengths independently of the conditions (open or laparoscopic) in which the measurements were done. The length of 250 cm for the AL is the results of decades of experience, and should not be changed, unless a longer AL is requested to reduce to the minimum the weight loss, as in the above mentioned particular indications. An AL shorter than 250 cm entails a progressively increasing risk of PEM.

The CL length of 50 cm has been our gold standard since the completion of the early experimental phase, and it has remained the same during more than 30 years, always giving excellent and indefinitely maintained weight results. However, it demonstrated to be incompatible with a gastric volume smaller than 300 mL, the so-called very little stomach BPD causing, besides a 90 % loss of the excess weight, an incidence of 30 % PEM, with more than 10 % recurrent form requiring surgical revision [2, 18, 24]. This was confirmed by Sugerman et al. [14] who had overwhelming PEM problems when, leaving the very small gastric pouch, they converted standard RYGB into BPD with 200 cm AL and 50 cm CL (so-called distal gastric bypass). In our experience with BPD evolution, the progressive enlargement of the gastric remnant brought the PEM down to around 3 % with 1 % recurrence rate, and the additional lengthening of the AL from 200 to 250 cm made this important nutritional complication to essentially disappear, still leaving the permanent loss of the excess weight around 70 % [24]. With similar more than 300 mL gastric remnant, Clare [25] reported good results with 50 cm CL and equal AL and BPL (as our “half-half” BPD [26]), with little less weight loss than the standard model and only 2 % of hypoproteinemia. The same good results were obtained by Marceau [27] with the 50 cm CL standard BPD. Still, the problems remained of side effects, mainly represented by diarrhea, present in 13 % of operated patients.

More recently, Garcia et al. [28] compared standard BPD (50 CL – 200 AL cm) with a modified version (75–225 cm), showing an astonishing fall of malnutrition from 16 to 2 %, with slight lower weight loss. These findings go into the same direction of the preliminary ones of a prospective randomized trial we are carrying out on our patients, where a 75 cm CL results in modest reduction of weight loss accompanied by a significant reduction of side effects, mainly diarrhea but also gas problems and foul smelling stools.

For the rest, different intestinal lengths were used in modified RYGB in order to achieve a greater weight loss, especially in the super-obese patients. To understand what the authors actually did is made difficult due to the apparently different semantics they use when defining the intestinal limbs. First, Brolin et al. in 1992 proposed the “long-limb” RYGB [15], consisting of a “defunctionalized jejunum” (and then a BPL) of 150 cm compared with a BPL of 75 cm. The first operation caused a greater weight loss when compared to the second one only in the super-obese patients, when weight loss did not change in the morbidly obese ones. These results were confirmed by MacLean et al. in 2001 [16] and subsequently by Brolin himself in 2005 [29]. The confusion arises when the “very very long limb” RYGB is considered. This operation, described first by Murr et al. in 1999 [17] and then by Nelson et al. in 2006 [30], both belonging to the same group of the Mayo Clinic, Rochester, Minnesota, apparently consists of a gastric bypass with a short (60 cm) “pancreatobiliary limb,” which evidently corresponds to what we call BPL, a 100-cm “common channel,” and thus our CL, while all the rest of the small bowel, from the GEA to the EEA, ranging in length between 400 and 500 cm, which is evidently our AL, is named “Roux-limb.” The authors refer to the Sugerman “distal gastric bypass” [14], who uses the same terminology, that is, “Roux-limb” = AL. Therefore, the Brolin and MacLean “long-limb” is apparently named “Roux-limb” and corresponds to the biliopancreatic limb (BPL), while the definition “Roux-limb” in the Sugerman distal gastric bypass and in the Rochester group “very very long limb” is evidently referred to the alimentary limb (AL). This gross semantic confusion, that I have repeatedly indicated as one of the greatest problems in bariatric surgery (I even wrote a chapter in the Deitel’s book entitled “Semantics in obesity surgery” [31]), certainly does not help the reader to understand how these operations are structured, and, even less, how they work.

At the beginning of the introduction, when describing the BPD as a basic mechanism of action, we underlined that the mechanism is effective in causing a reduction, or, to say better, a limitation of calorie absorption only if the time of contact between food and biliopancreatic secretions is reduced enough to cause incomplete digestion and absorption of calorie rich aliment. At this point, in order to fully understand the importance of the intestinal limb lengths, it is important to remember that not necessarily the BPD operation causes weight loss. BPD simply leads the body weight to the value corresponding to the amount of daily calorie absorption which is allowed by its mechanism of action. As we said, there is for each BPD individual a maximum energy absorption capacity which, in that specific subject, if all the other conditions mentioned above remain constant, also remains constant and corresponds to a determined weight of stabilization. If the starting body weight of the BPD subject corresponds to a daily energy consumption higher than the operation energy absorption threshold, a negative calorie balance takes place causing the reduction of body weight which will stop only when the body energy expenditure will equal the energy absorption threshold. Assuming, for example, that the threshold is 1,600 kcal/day, corresponding to the body energy expenditure of 85 kg, the latter will be the weight of stabilization of that subject for that operation. Any starting body weight higher than this will be forced by the negative calorie balance to reduce to 85 kg, when the energy balance is reached between daily intestinal energy absorption and daily body energy expenditure. The result will be a weight loss equal to the starting body weight minus 85 kg. However, if the starting body weight is already stable at 85 kg, this means that the BPD individual is eating and consuming as much as the operation allows to absorb. Consequently, the operation causes no negative energy balance, neither weight change. The same obviously applies to the case of starting body weight lower than 85 kg. The BPD subject eats and consumes less energy than what the BPD allows to absorb, then again nothing would change in calorie balance and no weight change would occur.

BPD possesses some metabolic specific actions which are totally independent of the weight loss, the best known being the serum cholesterol lowering and the beneficial effect on glycemic control. Consequently, the morbidly obese patient, in case of hypercholesterolemia or type 2 diabetes mellitus, besides weight loss will also benefit of these two weight-independent actions. They depend on the structure of the operation, the first being due to the loss of bile salts in the colon, caused by the short segment of bile salt absorbing terminal ileum in continuity, which causes increased bile acid neosynthesis in the liver which happens at the expenses of the cholesterol pool. The beneficial action on type 2 diabetes, first reported by us in 1984 [26], is caused by hormonal changes due to the bypass of the duodenum and by the presence of aliments in the ileum. If these anatomic conditions are preserved, the two beneficial specific actions remain active also in case of no weight loss. Therefore, the operation is precious, because it can be used for the treatment of hypercholesterolemia and of type 2 diabetes mellitus also in lean individuals, with no risk of undue weight loss. In those cases, as we do not know which the exact value of energy absorption threshold will be, in order not to take the risk of undue weight loss, we deliberately increase its level by elongating by 50 cm both the CL and the AL, which become 100 and 300 cm, respectively, thus obtaining the preservation of the above specific actions with minimal or no weight loss at all [24, 32]. Obviously, in these conditions, an increase of energy intake would cause weight gain, but this only exceptionally happens, and the same applies to the hypothetical weight gain resulting from the better glycemic homeostasis.

In conclusion, the good knowledge and the wise use of the intestinal limbs absorption characteristics makes BPD an extremely ductile operation, as it can operate in such a wide range of action that it can cause from the greatest weight loss obtainable with any bariatric operation down to even no weight loss at all, still maintaining its specific actions, like the two mentioned above.