A bougie is routinely used to size a LSG during stapler transection. The final volume of the sleeve will depend upon both the size of the bougie, the tightness of application of the stapler in relation to the bougie and also the use of imbricating sutures. No consensus exists as to what size of bougie is most effective. Though the aim would be to reduce the gastric volume as much as possible this has to be balanced with safety, as it is known from existing literature that more tighter the sleeve, the chances of leak could be higher, possibly because of higher intragastric pressures. Gagner et al. describe an inverse relation between the size of the bougie and the rate of leaks and advocate the use of catheters between 50 and 60 Fr [6]. However as 1 Fr is equivalent to 0.33 mm, 32 Fr bougies have a 1.1-cm diameter, 36 Fr bougies have a 1.2 cm diameter, and 40 Fr bougies have 1.3 cm diameter and so on thus making the differences between sizes minimal. Most authors reporting more than 50 % EWL after 1 year utilized different bougie sizes ranging from 32 to 48 Fr, whereas studies reporting EWL less than 50 % after 1 year comprised a bougie size ranging from 46 to 60 Fr [5, 7–11]. Weiner et al. compared three groups of patients (one in which no bougie is introduced to calibrate, one using 44 Fr catheters, and another using 32 Fr catheters) and concluded no differences in short-term results but, after 2 years, the results in favor of the more restrictive groups [12]. However in a systematic review and meta-analysis of 9991 cases Parikh et al. retrospectively compared results among patients that utilized 40 and 60 Fr catheters, with no differences between groups after 6 and 12 months. However they identified that utilizing a bougie ≥40 Fr may decrease leak without impacting %EWL up to 3 years [13]. In the International Sleeve Gastrectomy Expert Panel Consensus Statement majority voted size 32–36 Fr (translating to a diameter of 1.1–1.2 cm) as ideal. In India there exists a standard available bougie size of 38 Fr (12.7 mm, 38 Fr, Gastric Calibration Tube, Ethicon Endo-Surgery) which is most commonly used by most surgeons. Although some studies have suggested that bougie size impacts weightloss, in general most studies have shown variable results with regards to bougie size and weight loss outcomes. Hence it can be concluded that surgeons do not require to be too restrictive and a size of around 40F could probably be ideal.

Another important step to be considered in LSG is the length of antrum required to be preserved to maintain normal gastric emptying and understanding the effect of this on mid-term and long-term outcomes, as increased preservation may theoretically decrease the extent of restriction. Most authors in initial studies had performed the resection at 6–7 cm from the pylorus in order to preserve the entire gastric antrum to promote proper gastric emptying. Later surgeons moved closer to the pylorus, about 3–4 cm from the pylorus resulting in preservation of part of the antrum still allowing for good gastric emptying but increasing the restriction of the procedure. Mognol et al. and Baltasar et al. then advocated radical antral resection with a transection beginning about 2 cm from the pylorus to improve restriction, especially when it is performed as a standalone procedure. But the concern of failure of stomach evacuation after radical excision of the antrum existed. However gastric emptying studies have actually shown an increase in gastric emptying postoperatively even with radical resection of the antrum during LSG [14]. Complications such as failure of stomach evacuation were not observed suggesting that even more radical resection of the pyloric antrum with increased restriction is possible. In fact increased gastric emptying may actually be more beneficial to eventual weight loss. Sánchez-Santos et al., in the results of the Spanish National Registry, reported that groups who begin gastrectomy closest to the pylorus obtain better weight-loss results in the follow-up [15]. However in the large metanalysis by Parikh et al. comparison of <5 cm versus >5 cm showed no difference in leak rate or weight loss [13]. As per experts opinion in the International Sleeve Gastrectomy Expert Panel Consensus Statement majority voted that surgeons would prefer beginning the distal section 2–6 cm from the pylorus [16]. Thus as increasing data is supporting the beginning of the distal section closer to the pylorus it can be concluded that a distal section < or equal to 5 cm from the pylorus is ideal.

Studies performed by measurement of tissue thickness of human stomach on excised gastric specimens from obese patients show that stomach thickness varies from thinnest at the proximal end near the esophageal junction to thickest near the antrum [17]. Due to this variation in stomach thickness, laparoscopic linear cutting staplers should be tailored accordingly. As per experts opinion in the International Sleeve Gastrectomy Expert Panel Consensus Statement majority voted that nothing less than a blue load (closed staple height 1.5 mm) should be used on any part of a LSG. Some dissenters voted against because they recommended that nothing less than a green load (closed staple height 2.0 mm) should be used on any part of a LSG. It was voted that when using buttressing materials, anything lesser than green load should be avoided. When resecting the antrum, it is advisable not to use a stapler lesser than a green load (closed staple height 2.0 mm). When performing revision surgery, firings should be green or larger.

In routine practice staple loads could be blue, gold, green, or black for the Ethicon Echelon™ stapler or blue, green for the Covidien Endo GIA™ stapler or tan, purple, or black for the Covidien Endo GIA Tristaple™ load. The surgeon starts with the thickest load at the antrum and then chooses subsequent staple loads based on how the tissues feel. Interestingly a recent study showed that this subjective assessment has a high chance of choosing incorrect staple heights but implications of this in clinical practice is not known [18]. Considering the fact that the existing staplers have provided reasonably good outcomes and there presently exists no technology for intraoperative measurement of tissue thickness to guide the choice of stapler load, choice should be made according the anatomical location and subjective assessment of tissue thickness.

The distal esophagus and esophagogastric junction are supplied on the right and anterior side by branches of the left gastric artery and left inferior phrenic artery and on the posterior and left side by fundic branches of the splenic artery, the posterior gastric artery and the phrenic branches [19]. A LSG requires complete dissection of the fundus by division of the short gastric vessels, of the posterior gastric artery, and of the phrenic branches. Thus a “critical area” of vascularization may occur laterally, just at the esophago-gastric junction at the angle of His [19]. Hence one needs to take utmost caution at this region as undue ischaemia can increase the chance of leak. Also it is recommended that the proximal section (last section) is performed 1–2 cm away from the gastroesophageal junction [19].

It is also important to completely mobilize the fundus laterally and posteriorly before transection, removing the fundus completely, preventing the possibility of dilatation and subsequent weight regain as this is the most distensible portion of the stomach