Robotic Roux-en-Y gastric bypass: surgical technique and short-term experience from 329 cases

ABSTRACT Objective: minimally invasive bariatric surgery is clearly superior over open procedures including better early outcomes. Different surgical approaches are used to treat the severely obese, having Roux-en-Y gastric bypass (RYGB) being a highly frequent procedure. Robotic surgery overcomes some laparoscopic limitations adding ergonomics, articulating instruments and a three-dimensional high definition camera. Based on our vast robotic experience, we present our referred group case series and a standardized Robotic Roux-en-Y gastric bypass (rRYGB) technique as well as its outcomes. Methods: a review of a prospective maintained database was conducted in patients submitted to robotic Roux en Y bariatric surgery between April 2015 and July 2019. Surgical technique is described and illustrated. We also reported patients demographics, outcomes and its follow-up. Results: a Retrospective analysis identified 329 patients submitted to Robotic Roux-en-Y gastric bypass. Both da Vinci Si and Xi platforms were used. Mean age was 34.4 years, with median BMI of 44.2 kg/m2. Mean console time was 102 min and there was no conversion. No surgical hospital readmission rates were seen in the first 30 days. Conclusion: this study represents our initial experience of robotic Roux-en-Y gastric bypass (rRYGB), its short outcomes and a standardized surgical technique. Our results encourage that rRYGB is technically feasible and safe, and might offer some advantages showing good outcomes and minimal complications.

Robotic surgery gained popularity providing solutions to the challenges posed by laparoscopy, including ergonomics, a high-definition 3-dimensional camera, tremor filtration, a third surgeon arm and wristed instruments. In the bariatric surgical field, for example, these characteristics are translate into the ability to perform a better traction of a normally thick abdominal wall, relieving the surgeon's physical efforts to overcome the counterproductive forces, as well as a highly stable camera and better manipulation of the surgical structures.
The use of robotics in bariatric surgery has been evolving since Cadiere et al. 6 reported their first case, and it is now disseminated worldwide. However, training robotic surgeons is a highly demanding and expensive task. Still, a main limitation of robotic surgery is the perceived higher cost and set-up time compared with laparoscopy. The purpose of this article is to report our standardized robotic Roux-en-Y gastric bypass (rRYGB) technique offering suggestions for a successful learning curve and safe procedure, as well as highlighting potential solutions for common problems. Also, we present our group case series experience and the early outcomes.. they should be draped slightly posterior to the hemiaxilar imaginary line or on its limit, but never anteriorly.

METHODS
Positioning the arms, a bit "dropped" also helps to create space for the lateral port mobility. Antibiotic prophylaxis is routinely used with administration of intravenous cefazolin during anesthetic induction.

Port placement and instruments
Pneumoperitoneum is carried out with a A robotic port is subsequently placed along the patients right anterior axillary line, above the level of the camera port, which will be the surgeon's left hand. This port should be as lateral as possible, creating enough distance to the area where the assistant port will be placed. The Step-by-step robotic Roux-en-Y gastric bypass

Cavity inspection
First, the abdominal space is carefully inspected.
If present, previous adherences are analyzed to assure a safe pouch creation and the possibility of bringing a jejunal loop long enough to the supramesocolic quadrant for anastomosis. If previous liver to stomach adherences are present, they are first detached and then a liver retractor is positioned.

Pouch creation
The first step in our standardized rRYGB is creating the pouch and before starting dissection, stomach bougie aspiration by the anesthesiologist is asked for fluid evacuation if needed. Initially, the stomach is pulled caudally and the Hiss angle is dissected to assure an optimal visualization of the left crux ( Figure 1C

Mesenteric defect closure and bowel loop transection for a Roux-en-Y anatomy
After completion of the jejunojejunostomy, mesenteric defects are closed to avoid internal hernias with a running suture of Ethibond® 2-0 suture ( Figure   5D). This suture is done beginning in the deeper part of the meso running to its superficial part, ending close to the bowels. Finally, the bowel loop created for the gastrojejunostomy is transected using a 45mm linear stapler, detaching the jejunojejunostomy from the gastrojejunostomy, pursuing a small residual candy can and creating the Roux-en-Y anatomy ( Figure 6A).

Leak Test and drainage
The gastrojejunal anastomosis is tested with methylene blue dye administered through the oral bougie. Two sponge gauzes are placed posteriorly to the anastomosis and laterally to the pouch, close to the

Technical variations in the armamentarium
A recent addition to the robotic-assisted instruments is the da Vinci stapling technology. If available, the surgeons may choose to apply robotic staplers during the procedure and some technical aspects must be highlighted ( Figure 6C). Robotic staples must be used with 12mm width ports, demanding a strategic port placement design. In the rRYGB, all staplings are fired coming from the right to the left side of the patient. For a more practical and efficient technique, our group standardized a 12mm robotic port upfront in the patient's right anterior axillary line instead of the 8mm robotic port commonly used for the surgeon's left hand in arm n.1. By having this port setup, all staples are done through this 12mm port with no additional assistant port or camera and instruments exchange between robotic arms. Also, this technique allows a rRYGB with 5 incisions rather than 6 whenever using the laparoscopic stapler with an assistant port.   Besides that, potential benefits of robotic surgery could be more apparent in procedures such as the rRYGB, involving multiple suturing tasks and dissection in fatty and narrow spaces.
Most comparative data between laparoscopic and rRYGB come from observational studies and not from high-quality randomized controlled trials 10 .
Complex bariatric surgeries have already been described safely with the robotic system and with low complication rates 11 . The robot seems to be advantageous in superobese and revisional cases, however primary bariatric procedures such as RYGB could also benefit from the technology with lower anastomotic leak rates 10 . Also, regarding surgical education, the learning curve of rRYGB has also been shown to be shorter when compared to laparoscopic RYGB 12  The present study has focused more on a standardized technique instructing a step-by-step guide to a rRYGB rather than a comparison to bariatric procedures. We believe this report may elucidate and bring robotic surgeon trainees more safety and familiarity whenever performing a rRYGB. Our case series reported no surgical mortality or procedure related complications, showing feasibility as well as good postoperative outcomes. However, some known study limitations related to its intrinsic retrospective analysis are present. Although robotic surgery continues to increase in popularity, larger single-center or multicenter experiences are necessary and will continue to help clarify the role of robotics in primary and also revisional bariatric surgery.

CONCLUSION
This study represents our initial experience of robotic Roux-en-Y-gastric bypass and a standardized technique. In this retrospective analysis, our group shows that a standardized rRYGB technique using robotic technology in experienced surgeons' hands allows a safe procedure and shows encouraging outcomes. Digital platforms are promising in the surgical field although they still require prospective randomized trials to access its real benefits.