The restrictive effect of LRYGB is obtained by creating a small gastric pouch along the lesser curvature with a narrow gastrojejunostomy. It is further accentuated through bypassing the stomach, duodenum, and various lengths of the proximal jejunum, as well as dumping, stasis, and changes of gastrointestinal hormones such as ghrelin. Roberts et al. have suggested that it is actually pouch volume more than stoma diameter that truly impacts satiety and affects weight loss [2].

In LRYGB, the pouch formation is the most demanding part of the operation. The laparoscopic perigastric dissection technique, especially in super obese or male patients with a big amount of local fatty tissue, may be very demanding and comes along with a higher intraoperative complication rate due to bleeding or disorientation. Preservation of vagus nerve is essential during pouch formation to reduce post-operative dumping syndrome [3].

Kelvin Higa has suggested that the first firing during the creation of pouch should begin no more than 5 cm distal to OG junction [4]. He has also suggested dissection of hiatus routinely and repair of the hiatal hernia along with removing the fat pad overlying the angle of His, which according to him will allow more precise and consistent pouch creation with better long term performance and lower complications. Radwin Kassir et al. have suggested the transverse firing of the first stapler to be at 6 cm distal to the cardia or 2 cm proximal to the incisura for an ideal pouch size [5]. Gastric pouch anatomy plays a significant role in weight loss in addition to volume. Capella at al demonstrated that long narrow pouches have less tendency to enlarge and should delay the transit more than wider pouches and produce better weight loss [6]. Hence, an ideal pouch is a small narrow pouch based on the lesser curvature.

Since the introduction of the laparoscopic technique in 1994, a variety of surgical techniques to construct the gastrojujenal (GJ) anastomosis have been developed, with no consensus on one ideal technique. Three types of anastomosis are commonly performed: hand-sewn anastomosis (HSA), linear-stapled anastomosis (LSA), and circular-stapled anastomosis (CSA). Literature has been conflicting regarding the superiority of a particular technique, in reducing the early complications [7–9]. In the USA, the percentage of surgeons using the circular stapler, linear stapler and hand sewing for GJ is 43, 41 and 21 % and the selection of a particular anastomotic technique is usually based on the surgeon’s preference [10].

Anastomotic leak and stricture formation are the well known complications of GJ. Various studies have yielded different rates of stricture from 3 to 8 % with HSA, 0 to 6 % with LSA, and 5 to 31 % with CSA. Many series have shown that the use of a 21-mm circular stapler is associated with higher rates of stricture, and most surgeons prefer the use of 25-mm circular staplers to avoid this complication [8, 11–22]. Nguyen et al. and Cottan et al. found no significant difference in weight loss while using either 21 or 25 mm circular stapler [13, 23].

Studies have shown comparable outcomes in terms of weight loss when using either linear or circular stapler in GJ [9, 12, 24, 25]. A meta-analysis by Giordano et al. including eight studies comparing CSA and LSA found a statistically significant benefit for the LSA group with a reduced risk of developing a GJA stricture, reduced risk for wound infections and a significant shorter operative time, while no significant differences in the risk of leakage and weight loss at 1-year follow-up [7, 9, 12, 25]. Another meta-analysis by Penna et al. confirmed these results [26]. The anastomotic leak rate for circular stapler is about 0–6.6 %, while for linear stapler it is 0–5.1 % [8]. The issues of GJ leaks and stricture have been discussed in detail later in under Chap. 26 and 27.

There is currently no consensus on the technique of choice, as most of the series published, conclude that all three techniques are safe for performing GJ anastomosis in LRYGB and there are no significant differences regarding the complications. However, these studies are limited by the fact that most centers specialized in bariatric surgery use just one type of GJ anastomosis. Moreover, the studies comparing different GJ anastomotic techniques are retrospective, with a disparate number of patients in each group and, in most cases, limited follow-up. Extrapolating this data, an ideal stoma diameter would be 25 mm irrespective of the technique used.

The mechanism by which LRYGB induces weight loss includes a restrictive and a malabsorptive component. The small gastric pouch restricts the amount of food that can be ingested, and the bypass of a segment of duodenum and small bowel provides a degree of malabsorption. The degree of malabsorption can be modified by altering the length of these limbs. Though most surgeons use a body mass index (BMI) cut off to vary the length of their limbs, variability exists amongst surgeons even for similar patient BMIs [27].

Brolin et al. in a randomised controlled study randomized superobese patients (n = 45) to a 75 cm alimentary limb (biliopancreatic limb = 15 cm) versus a 150 cm alimentary limb (biliopancreatic limb = 30 cm) LRYGB. They concluded that a longer limb resulted in significantly greater weight loss than conventional LRYGB but did not cause additional metabolic sequelae or diarrhea [28].

Choban et al. in a randomised controlled study randomized patients with a BMI ≤50 (n = 69) to a 75 cm versus a 150 cm alimentary limb and those with a BMI ≥50 to a 150 cm versus a 250 cm alimentary limb (biliopancreatic limb = 30 cm in all) LRYGB. They concluded that there was no benefit to longer Roux limb lengths for patients with BMI <50 but in superobese patients longer alimentary limb-lengths may be associated with a higher percent of patients achieving >50 % EWL. Thus superobese might benefit from Roux limbs of atleast 150 cm [29].

Inabnet et al. in a randomised controlled study randomized patients with a BMI ≤50 (n = 48) to an either a short limb (biliopancreatic limb = 50 cm, alimentary limb = 100 cm) or long limb (biliopancreatic limb = 100 cm, alimentary limb = 150 cm) LRYGB. They observed no weight loss or nutritional differences between the two groups up to 1 year postoperatively but noted a higher incidence of internal hernias in the longer-limb group. They concluded that increasing the Roux limb length in non-superobese patients did not improve weight loss and may increase the incidence of internal hernias. The main limitation of this study was its short follow-up and its small sample size [30].

The study by Christou et al. reported the longest follow-up to date (10 years) and did not demonstrate a benefit to longer Roux limbs independent of BMI in the long term [31].

Interestingly, a recently published study by Savassi-Rocha et al., based on the total length of the small intestine which is between 400 and 900 cm, concluded that constructing longer Roux limbs in the range of 150 cm is unlikely to lead to better weight loss in the majority of patients when the common channel length is not considered [32]. A few publications considered the length of the common channel during the creation of the gastric bypass. Nelson et al. reported results of a postoperative survey on mostly superobese patients that received a distal bypass with a 100-cm common channel, with follow-up of 4 years, 82 % patients losing >50 % of their excess weight [33]. Furthermore, resolution of diabetes reached 94 %, hypertension 65 %, sleep apnea 48 %, and patient satisfaction with the surgery was 90 %. Nevertheless, many patients experienced mild food intolerance and occasional loose stools (71–82 %) with 4 % of patients requiring reoperation with proximal relocation of the Roux limb for symptom resolution. The study by Brolin et al. found that distal RYGB (75 cm common channel) was more effective than a 150-cm Roux but at the expense of higher malabsorptive complications and a small but real incidence of reoperation for reversal [34].

Higa in his data has reported that varying the biliopancreatic limb up to 100 cm has failed to show a difference in excess weight loss in the long term [4].

In conclusion, the currently available literature supports the notion that a longer Roux limb (at least 150 cm) may be associated with a very modest weight loss advantage in the short term in superobese patients but has no significant impact on patients with BMI ≤50. Nevertheless, there is convincing evidence that the degree of malabsorption after RYGB is influenced mainly by the length of the common channel rather than the lengths of the Roux or biliopancreatic limbs as constructed currently by the majority of bariatric surgeons.

Internal hernias (IH) are a known potential complication of LRYGB. The incidence of IH has been reported to range from 3 to 4.5 % after LRYGB [35, 36]. The incidence of internal hernias with LRYGB is more when compared to open surgery due to decreased adhesion formation during laparoscopic surgery. Management of internal hernias have been discussed in detail later in the chapter 24 on internal hernias.

Three anatomical spaces have been described as the possible sites for the internal hernias caused by this surgery:

The location of internal hernias has been documented with transverse mesocolon hernias commonest followed by entero-enterostomy and then Peterson’s space hernias.

Routine closure of all potential defects with non-absorbable sutures is generally preferred [37]. While these are all laudable measures, more significant technical changes such as antecolic versus retrocolic may produce more significant reduction in the incidence of IH [38]. Champion and Williams mention that there was no reduction in IH after closing the mesentery in a retrocolic technique, while there was a significant reduction when using the antecolic technique, even without closure [39]. Higa et al. did refer to a large reduction in numbers after closing the mesentery in the retrocolic technique employing nonabsorbable sutures, although there was still a 3 % rate even after the closures [40]. Miyashiro et al., in results shared by Carmody et al., mention the complete absence of IH after using the retrocolic technique with the closure of the mesentery, pointing out that out of the 1.3 % of patients with intestinal obstruction, none were caused by IH [41, 42]. A large series of 1,400 patients undergoing LRYGB with an antecolic GJ without closure of any potential hernia defects reported an extremely low incidence of internal hernias [43].

Christopher W et al. published no IH in their technique without closure of the defects which included an antecolic ante-gastric gastrojejunostomy (GJ), division of the greater omentum, a long jejunojejunostomy (JJ) performed with three staple-lines, a short (<4 cm) division of the small bowel mesentery, and placement of the JJ above the colon in the left upper quadrant. Mazen R. Al-Mansouret al noted an IH incidence of 6.2 % in their study while the literature reports a 0–6.9 %. Incidence of IH changed after a routine closure of Petersen’s space defect reducing the percentage of patients with Petersen hernias from 83.9 to 33.3 %, therefore submitting that closure of Petersen’s space defect has the potential to reduce the incidence of IH after RYGB.

Hence it’s preferred to close all potential defects using non-absorbable sutures, although the outcomes of closure of Petersens defect still remain controversial.

Stomal dilatation has been long recognized as one of the causes of weight regain after LRYGB. Interventions to reduce the size of the gastric pouch or stoma may help reinitiate weight loss [44]. These findings have led some surgeons to believe that placement of a band proximal to gastrojejunostomy at the time of the primary operation will reduce dilatation of gastric pouch, stoma and small bowel, thus resulting in superior long-term weight loss outcomes. Linner’s concept of preventing weight regain by reinforcing the stoma against dilating was reintroduced in 1989 by Fobi et al. by placing the band around the gastric pouch, as used in the vertical banded gastroplasty and silastic ring vertical gastroplasty [45]. This modified gastric bypass appears to provide more weight loss that is maintained over a longer period of time [46]. Fobi et al. found that >90.0 % of patients lost and, more importantly, maintained ≥50.0% EWL at ≥5 years [47].

The randomised controlled trial by Bessler et al. of banded and non-banded bypass in super-obese patients showed a statistically significant superior weight loss at 36 months in the banded group compared to the non-banded group [46]. Heneghan et al. found statistically superior weight loss in banded bypass patients at 24 months compared to the nonbanded bypass group in their matched cohort study. On subgroup analysis, they found a significant weight loss difference in those with BMI >50 but not in those with BMI <50 [48]. Awad et al. confirmed significantly better weight loss with banded bypass in their long-term retrospective comparison of banded and non-banded bypass [49].