Robotic Roux-en-Y Gastric Bypass

Abstract

Obesity and bariatric procedures have risen over the years, leading to surgeons encounter with patients having very high body mass index. Digital platform holds promise for these patients and robotic surgery is regarded as an attractive technology for use in morbidly obese particularly in extreme obesity. Roux en-Y gastric bypass is a time-tested successful operation with excellent results in super obese. Roux en-Y gastric bypass though described more than 60 years earlier, has been popularised after advent of laparoscopic reconstruction techniques including staplers. Robotic Roux en-Y gastric bypass is an advancement in minimal invasive procedures over laparoscopic procedures with significant advantages in super obese. Robotic Roux en-Y gastric bypass is the most studied robotic bariatric procedure.

Introduction

In the last decade, bariatric surgery has witnessed an ever-increasing demand with rise in the prevalence of obesity. Laparoscopic Roux-en-y gastric bypass (LRYGB) was described in 1990s [1] and currently more than 100,000 procedures are estimated to be performed annually alone in United States [2]. According to American Society for Metabolic & Bariatric Surgery (ASMBS) estimate published in July 2015, RYGB constitutes 26.8% of total bariatric surgery volume.

Bariatric surgery is a technically demanding surgery particularly in situations with huge patients with large livers, thick abdominal walls and substantial visceral fat making exposure, dissection and reconstruction difficult [3]. The super obese patients (SO) with a body mass index (BMI) greater than or equal to 50 kg/m² is a difficult to manage population because of limited working space, excessive torque, on instruments due to thick abdominal wall, co-morbidities and high-risk anesthesia [4]. The maneuvering of instruments while performing LRYGB often becomes difficult, particularly while doing intra-corporeal suturing. All these lead to a longer learning curve for LRYGB, which has been estimated to be around 75–100 cases [5, 6]. Along with the difficulty, the surgeons encounter very difficult ergonomic positions during LRYGB which can potentially be career shortening, and whereas on one hand methods to improve the patient outcomes, surgical technique and decrease complications are being targetted, on the other hand concomitant reduction of the learning curve is being aimed.

Use of robotics in bariatric surgery has been evolving since Cadiere GB et al. reported the first such case in 1999 [7]. Robotic surgery has provided the surgeons with the advantage of three-dimensional vision, increased dexterity and precision by downscaling surgeon’s movements enabling a fine tissue dissection and filtering out physiological tremor [8, 9]. In morbidly obese it overcomes the restraint of torque on ports from thick abdominal wall and minimizes port site trauma by remote centre technology [10]. Consensus document on robotic surgery prepared by the SAGES-MIRA Robotic Surgery Consensus Group, claims robotic surgery to hold particular value for gastric bypass amongst general surgical procedures.

The main limitation of robotic surgery is its higher cost and robot setting up time compared to laparoscopy, but with increased experience, it is seen that setup times reduce and costs may also come down as material prices reduces [11].

Roux-en-Y Gastric Bypass (RYGB)

RYGB is often considered as the gold standard surgical procedure for morbid obesity [12, 13]. Overall results are good in terms of both weight loss and comorbidity resolution [14]. RYGB leads to an excess weight loss to the tune of 65.7%, while remission rates of type 2 DM being 66.7% and for dyslipidemia being 60.4% [15]. RYGB is done by creating two gastrointestinal anastomoses namely gastrojejunostomy and jejunojejunostomy. Robotic surgery is currently considered as a valuable technology that could help perform RYGB, given its well described benefits [16]. Robotic RYGB (R-RYGB) is today the most studied robotic bariatric procedure [17, 18].

Surgical Technique

There are many ways by which R-RYGB can be performed. The major variations in technique are listed below:

• (a) Single docking vs. double docking

• (b) Hybrid (Laparoscopic + Robotic) vs. Totally Robotic

• (c) Antecolic vs. Retrocolic alimentary limb

• (d) Handsewn, linear or circular stapler anastomosis for gastrojejunostomy

• (e) Staple line reinforcements or oversewing

The technique of choice at University of Illinois Health System is to perform a single docking totally robotic RYGB with a handsewn gastrojejunostomy. We describe this technique in the following paragraphs.

Instrumentation (Fig. 1)

The following 8 mm robotic instruments are used for a R-RYGB in a da Vinci Si system:

• (a) Cadiere forceps

• (b) Large needle driver

• (c) Da Vinci Harmonic scalpel

• (d) Permanent Cautery hook

• (e) Fenestrated bipolar forceps

• (f) Laparoscopic/Robotic staplers

Fig. 1

Robotic Instruments

All three arms of the robotic system are used with third arm coming from the left side of the patient (explained in docking).

Patient Positioning & OR Setup (Fig. 2)

The patient is positioned in supine position with 15–20⁰ reverse trendelenberg tilt under general anesthesia. This position helps to complete the procedure in a single docking, as both infracolic and supracolic portions of the procedure can be done without changing the position. The abdomen is cleaned and draped and orogastric tube/urinary catheter (optional) are placed. Assistant surgeon stands by the side of the patient along with the scrub nurse. The master console should be placed in such a way that the surgeon is able to freely visualize the operative field while sitting on the console. It is important that two video monitors are placed on both sides of the patient to enable the assistants to easily watch the monitor and if required to help at every step of procedure, with ergonomic comfort. The anesthesia machine is also kept on one side of the head end as patient cart comes in from the head end.

Fig. 2

Operating room setup and patient cart positioning for robot assisted RYGB

Port Position (Fig. 3a, b) and Docking (Fig. 4)

Pneumoperitoneum is achieved to 15 mm Hg using a Veress needle at palmer’s point. All the distances between ports are measured after insufflation of abdomen as they significantly change after pneumoperitoneum is created, especially in morbidly obese with pendulous abdominal wall. The minimum inter-trocar distance recommended in robotic surgery is 8–10 cm as the actual distance intraperitoneally in morbidly obese individuals is markedly shorter than the distance measured on the surface. This factor has to be always taken into consideration and trocars placed at maximum possible distance to avoid internal arm clashing of robot. The port placement needs to be adjusted based on the body habitus of each patient so as to prevent external arm collision and also provide optimal exposure.

Fig. 3

(a) Schematic diagram of port positions for Robot assisted RYGB; (b) Port position for Robot assisted RYGB

Fig. 4

Operating room with a docked robot

Camera port (12 mm diameter, 150 mm long trocar) is placed 20 cm below the xiphisternum slightly to left of midline under vision using a zero degree 10 mm scope to avoid any inadvertent visceral injury. Following this, one assistant and three da vinci trocars are placed as follows:

• R1: (8 mm da vinci^® cannula) is placed in left mid clavicular line approx. 20 cm from xiphisternum

• R2 (8 mm da vinci^® cannula) is placed in right hypochondrium in mid clavicular line taking care that the entry of port is below the margin of liver.

• R3 (8 mm da vinci^® cannula) is placed in left flank at the level of camera port.

• Assistant port (12 mm diameter) is placed in between camera port and R2 with a distance of at least 10 cm from both of them.

• A 5 mm epigastric port is made and used for placing Nathanson liver retractor for retracting left lobe of liver.

The da Vinci^® patient cart is brought from head end of the patient, and the arms are docked to the ports placed. The third arm of the robot comes from left side of the patient. To start the procedure, a permanent cautery hook is taken in R1, fenestrated bipolar forceps in R2 and a Cadiere forceps in R3. The assistant surgeon stands by the side for complementary maneuvers (i.e., suction, stapling, retraction etc.). A sample OR setup for RRYGB is depicted in Fig. 2. Diagnostic laparoscopy is done to look for any adhesions/hernias/inadvertent injury during abdominal wall access.

Creation of Gastric Pouch

Dissection should be started from the left crus by bringing the phrenoesophageal membrane down using the hook after caudally retracting the fundus of stomach (Fig. 5). Gastric pouch is created using perigastric dissection starting at the second vessel from gastroesophageal junction. Third arm is used to retract stomach laterally while harmonic scalpel opens the gastro-hepatic ligament. Perigastric dissection is done using hook avoiding injury to vagus nerve and lesser sac is entered. Stapler is fired horizontally which is done by the assistant using a 60 mm blue cartridge. Dissection is continued further superiorly to free the posterior adhesions of the stomach. Bougie may also be placed at this time to size the pouch. The vertical firing is done and pouch creation is completed (usually a single 60 mm fire, but two may be needed). The seven degrees of freedom help dissect in this area, especially around the left crus. Staple line reinforcements can be used in the vertical firings.

Fig. 5

Initial dissection around left crus: Bowel grasper is retracting the fundus caudally while monopolar hook dividing the phreno-esophageal membrane. The gastric pouch creation is simplified by this dissection

Creation of Jejuno-Jejunostomy (JJ)

The camera now needs to focus towards the infracolic part. The transverse colon is lifted up and ligament of trietz is identified. Jejunum is measured from ligament of treitz for 60 cm and divided using stapler. Biliopancreatic limb is held static by the third arm while 120 cm of roux limb is measured and the site for jejuno-jejunostomy identified. Then the bowel loops are held together while enterotomy is created using cautery hook (Fig. 6). Using the third arm to hold limbs together, time for a stay suture is saved and the operation runs more efficiently.

Fig. 6

While creation of jejuno-jejunostomy the second and third arm can hold both the loops of jejunum together saving time. Enterotomy is created by monopolar hook

A jejuno-jejunostomy is created using a 60 mm stapler (Fig. 7). The enterotomy is closed using PDS 3-0 running suture with large needle driver. Omentum is divided using harmonic scalpel and roux limb is taken up to gastric pouch for gastro-jejunostomy (GJ). Polypropylene suture is used to close the mesentric defect after GJ creation to avoid tension on the mesentery while roux limb is taken up to the gastric pouch.

Fig. 7

Creation of stappled jejunojenostomy

Creation of Gastrojejunsotomy (GJ)

PDS 3-0 suture is used to create a completely handsewn GJ. Marginal ulceration and stricture formation are seen if non absorbable suture is used. To create the GJ, the third arm holds the gastric pouch and small bowel together while R1 & R2 has two needle holders. Through and through continuous running suture is taken across the staple line and roux limb of jejunum, from left to right (Fig. 8) which continues as the posterior layer of GJ and importantly distributes the tension evenly across the staple line. A 1.5 cm gastrotomy (Fig. 9) and enterotomy is made using cautery hook which is estimated to be equal to three lengths of horizontal portion of hook. The anastomosis is started from the left corner which is continued with a running full thickness suture ultimately forming the posterior wall of GJ ending at the right corner of anastomosis. Similar full thickness anterior layer of GJ is also done from left to right with the ends of sutures knotted securely at the right side. Finally, the anterior sero-serosal layer is completed from left to right side. Ambidexterity is the basis of a robotic platform which allows the needle holder to be driven effectively in all directions during creation of GJ. Often four pieces of 6 inches PDS 3-0 is required to complete the 4 layered GJ (Fig. 10).

Fig. 8

Posterior layer of gastrojejunostomy between Pouch (P) & Jejunum (J)

Fig. 9

Gastrostomy being done using ultrasonic dissector. (P—Gastric Pouch)

Fig. 10

Creation of hand sewn gastro-jejunostomy using PDS 3-0 suture. Stability is maintained by the third arm, which is holding the gastric pouch and roux limb together

Peterson defect is closed starting from the base of the ‘V’ type opening basically by lifting up the transverse mesocolon and working towards the top. This is also done using polypropylene suture, taking care that no mesentric vessel is injured in this maneuvre. An intraoperative check esophago-gastroscopy is done with air leak test in all the cases at end of the procedure.

Perioperative Care

Deep venous thrombosis prophylaxis by pharmacological (Low molecular weight heparin) and mechanical (sequential compression devices, ambulation) methods are mandatory. Antimicrobial prophylaxis with a single shot of cephalosporin and patients started on liquid diet. They are often encouraged to walk in the evening of surgery. No upper GI gastrograffin study is done except in very selective cases like intolerance to liquids or prolonged nausea. The patients are kept on liquid diet for 1 week followed by a week of soft diet. Thereafter, they are progressed to normal diet intake as per the schedule.

Outcomes and Results

Robotic surgery is a team effort, and more so in bariatric surgery, where the role of an experienced OT table side surgeon cannot be understated, as he is also responsible for stapling (if robotic staplers are used). Main surgeon in the console is always slightly away from the patient while performing robotic surgery, hence the assistant surgeon also has to be trained to perform difficult tasks and also to take care of any emergency situation arising during the procedure. The entire team has to learn with the surgeon and develop knowledge about patient safety, operating room setup, types of instruments used or needed, thus leading to better OR times and better patient outcomes. The role of a trained scrub nurse and operating room technician is also very important in streamlining the conduct of the procedure and prevent any wastage of time and resources.

Lesser operator fatigue and improved ergonomics are the main advantages of a robotic platform. Ergonomics in laparoscopic surgery can be very challenging particularly with big patients and uncomfortable postures, which leads to fatigue and work-related musculoskeletal problems [19]. Robotics provides the advantage of more degrees of freedom, which is advantageous in performing difficult dissection and sutured anastomosis. Many significant published series compare outcomes of R-RYGB vs L-RYGB [20,21,22,23,24,25,26,27,28,29] where they primarily compare intra-operative and post operative outcomes.

Duration of Surgery: Initially time taken for totally R-RYGB or Hybrid R-RYGB is more compared to L-RYGB, as additional time is taken in docking and undocking which is compounded by the fact that mostly a sutured anastomosis is done in the robotic surgery while a stapled anastomosis is done in laparoscopic arm. If done similarly, intra-operative step by step, procedure time if calculated can be less in R-RYGB due to improve dexterity and 3-D vision with robotic surgery. Further once the robotic team gets experienced the whole procedure time can also decreases significantly [30].

Perioperative issues: Blood loss is comparable in both R-RYGB & L-RYGB. GI-Bleeding, leaks and venous tromboembolism are regarded less with R-RYGB due to its increased operative precision [31].

Post operative markers: Post-operative CRP values are always lower with R-RYGB which can be regarded as a more precise and less traumatic approach. Haemoglobin and leukocyte values have been insignificantly different [30].

Length of hospital stay: Unremarkably different in robotic and laparoscopic patients. Many other compounding factors add to the hospital stay including co-morbidities, national peculiarities of patient care and billing [30]. Average length of stay is 5 days in robotic group vs. 7.1 days in laparoscopic group [32].

Issues with Gastro intestinal anastomosis: Various anastomotic techniques are used for R-RYGB which includes linear stapler and circular stapler anastomosis or one of the complete hand sewn suture techniques [33]. Hand sewn anastomosis compared to circular stapler anastomosis results in lower wound infection rates and lower gastro-intestinal bleeding. The average leak rate across studies is 0.9% in R-RYGB vs 1.6% in L-RYGB, while the GJ stricture rate is 3.1% in robotic arm and 3.2% in laparoscopic arm [32].

GJ stricture rates are highest with 21 mm circular stapler verified by endoscopy [31] as these cases often require repeated endoscopic dilatation over a 5 year period. Use of 3.5 mm stapler height can ameliorate some problems of using circular staplers [21, 34].

Readmissions, Re-operation & Revision operations: Readmissions rates have been similar in all types of RYGB while re-operation & revisional surgery after R-RYGB is less even during the first 100 cases of each surgeon [30, 31]. Common indications for re-operations other than acute leaks can be partial omental necrosis.

Costs: An obvious concern is about the cost of procedure every time when a robotic system is considered as the direct costs are significantly higher for the robotic approach in bariatric procedures like R-RYGB [35]. However, if taken into account the total costs including the post-operative stay, complications and readmissions, the cost of R-RYGB might be lower as compared to L-RYGB [25]. Major saving is also due to decrease in number of staplers in robotic procedures, compensated by a robotic hand sewn anastomosis.

Learning curve: The learning curve of both L-RYGB and R-RYGB has been a matter of concern. Learning curve for LRYGB (75–100 cases) [5, 36] is much higher to R-RYGB (14 cases) [16] in order to normalize complications by a surgeon well versed in laparoscopic surgery but not in bariatric procedures and achieve mastery in the particular type of surgery. Complications in first 100 cases of R-RYGB are also comparatively less [37].

Surgeon skill bias is at stake in majority of these reports as it is very difficult to find a surgeon equally skilled in both robotic and laparoscopic techniques. Most of the surgeons and their teams become proficient in either of the two techniques, but large comparative studies and systematic reviews do offer some tendencies for robotic bariatric surgery [38,39,40].

Conclusion

Big question to be answered is whether the use of robotics is going to stay or will it perish with time like many fancy technologies. Looking at the basic concept of computer assisted navigational surgery, robotics provide an enabling platform in between surgeon and the patient. It provides augmented and higher quality inputs from the patient to the surgeon and his output is refined to a superior quality before reaching back to the target. All this should not be analyzed in terms of features of the present machine that is available for use, but in terms of the potential in the concept of using a digital interface to interact with patients and enhance the performance of the surgeon. With the advent of newer technologies in robotics like fluorescence, integration of images, virtual and augmented reality, telesurgery, single site platforms, natural orifice surgery and haptic feedback, it is believed that digital platforms will provide an empowering tool to the surgeons which can potentially change the way surgery is practised today.

Key Clinical Notes

• 1. Robotic surgery is a team effort and more so in bariatric surgery. Role of an experienced bedside surgeon cannot be understated, as he is also responsible for many difficult tasks and also to take care of any emergency situation arising during the procedure.

• 2. Robotic surgery has provided the surgeons with the advantage of three-dimensional vision, increased dexterity and precision by downscaling surgeon’s movements enabling a fine tissue dissection and filtering out physiological tremor.

• 3. Robotic Surgery in morbidly obese overcomes the restraint of torque on the ports from thick abdominal wall and minimizes port site trauma by their remote center technology.

• 4. RYGB is often considered as the gold standard surgical procedure for morbid obesity with good overall results in terms of both weight loss and co-morbidity resolution.

• 5. In R-RYGB, patient is in supine position with 15–20⁰ reverse trendelenberg tilt which helps complete the procedure in a single docking fashion, as one is able to perform both infracolic and supracolic portions of the procedure without changing the patient position.

• 6. Actual intraperitoneal distance between ports in morbidly obese individuals is significantly shorter than the distance measured on the skin. Hence inter-trocar distance should be minimum 8–10 cm in robotic surgery to avoid internal arm clashing of robot.

• 7. All enterotomies are closed with 3-0 PDS suture. Non-absorbable sutures are avoided as it causes marginal ulceration and later stricture formation.

• 8. Peterson defect is closed starting from the base of the defect by lifting up the transverse mesocolon and working towards the top, avoiding any mesenteric vessel.

• 9. Time taken for totally R-RYGB or Hybrid R-RYGB is more compared to L-RYGB

• 10. Hand sewn anastomosis compared to circular stapler anastomosis results in lower wound infection rates and lower incidence gastro-intestinal bleeding.

• 11. Readmissions rates have been similar in all types of RYGB while re-operation & revisional surgery after R-RYGB is less.

• 12. Direct costs are generally significantly higher for the robotic bariatric procedures like R-RYGB

Editor’s Note

References: Main chapter references are included after the “References Editor’s Note” section.

Indications and Complications of RYGB

RYGB can be done as a primary procedure in (1) super obese (2) obese patients with comorbidity (3) revisional procedure after failed restrictive surgery. Long term nutritional deficiency remains an important concern with the procedure. The other complications related to the anastomosis are bleeding from staple line, anastomotic leak, gastro jejunal stomal stricture, marginal ulcers, bowel obstruction and formation of internal hernia. A higher incidence of biliary disease has also been reported in patients undergoing RYGB [1].

Minimally Invasive Surgery Versus Open RYGB

Minimally invasive techniques viz. laparoscopic and robotic RYGB have definite distinctive advantages over open surgery. In a systematic review and Bayesian network meta-analysis comparing open, laparoscopic, and robotic approach the laparoscopic and robotic approaches had better outcome as compared to open related to complication, surgical site infection, pulmonary infection and anastomotic leak rates [2].

Laparoscopic Versus Robotic RYGB

A few meta-analyses have evaluated the outcome of laparoscopic versus robotic RYGB(Table EN1) [3–5]. The technical advantage quoted of robotic RYGB over laparoscopic RYGB is the ease of constructing a gastrointestinal anastomosis with the Endo wrist instruments. In a meta-analysis comparing robotic and laparoscopic RYGB, significantly less anastomotic stricture was noted in robotic as compared to laparoscopic group [4]. However most other meta-analyses do not demonstrate any significant difference in leak rate, stricture or morbidity when comparing robotic and laparoscopic RYGB (Table EN1) [3, 5]. The important quoted disadvantage of robotic RYGB is the higher cost of the procedure. In construction of the gastric pouch a higher number of stapler cartridge refills are required in the robotic Endo-wrist Stapling System (EWSS) which is 45 mm versus 60 mm staplers used in laparoscopic surgery [6].Other techniques being explored is the use of barbed suture in construction of anastomosis [7].

Antecolic Versus Retro Colic RYGB

In a meta-analysis comparing antecolic ante gastric (AC + AG), versus retro colicretro gastric(RC + RG) anastomosis in laparoscopic RYGB, a higher incidence of bowel obstruction and internal hernias were reported in the retro colic/retro gastric group (bowel obstruction in 1.4% patients in the AC/AG group and 5.2% patients in the RC/RG group, P < 0.001). Internal hernias were reported 1.3%patients in the AC/AG group and 2.3% patients in the RC/RG group (P < 0.001) [8].

Biliary Disease After RYGB

There is a growing concern regarding increased incidence of biliary disease after RYGB. The two issues of contention are:

• (i) performance of a concomitant cholecystectomy with RYGB

• (ii) method of performance of ERCP after RYGB when needed.

A Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program propensity-matched analysis of Roux-en-Y gastric bypass with concomitant cholecystectomy in 117,939 minimally invasive RYGB have noted no increase in morbidity with performance of concomitant cholecystectomy [9].

The options available for performance of ERCP after RYGB are:

• (i) Laparoscopy assisted ERCP

• (ii) Balloon Enteroscopy assisted ERCP

Both procedures reported to yield equivalent results [10].

OAGB (One Anastomosis Gastric Bypass) vs RYGB

In a meta-analysis comparing OAGB with RYGB, leaks, marginal ulcer, dumping, bowel obstruction, revisions, and mortality was similar between the two approaches. OAGB was found to be superior with respect to weight loss and diabetes remission but had higher malabsorptive complications [11].

Revisional RYGB

RYGB as a revisional surgery following restrictive procedures like sleeve gastrectomy is done to achieve additional weight loss or due to complications. In a study of revisional RYGB following sleeve gastrectomy the complications which necessitated the conversion were: refractory GERD (40.5%), sleeve stenosis (31.0%), gastrocutaneous fistula (16.7%) or gastropleural fistula (7.1%) fistula, and gastric torsion (4.1%). The procedure could be performed safely both by laparoscopic and robotic technique [12].

Table EN1 Meta-analysis on outcome of robotic RYGB compared with laparoscopic and open procedures

References for Editor’s notes

• 1. Cunningham RM, Jones KT, Kuhn JE, Dove JT, Horsley RD, Daouadi M, Gabrielsen JD, Petrick AT, Parker DM. Asymptomatic Cholelithiasis and Bariatric Surgery: a Comprehensive Long-Term Analysis of the Risks of Biliary Disease in Patients Undergoing Primary Roux-en-Y Gastric Bypass. Obes Surg. 2021 Mar;31(3):1249–55. https://doi.org/10.1007/s11695-020-05125-8. Epub 2020 Nov 23. PMID: 33230759.

• 2. Aiolfi A, Tornese S, Bonitta G, Rausa E, Micheletto G, Bona D. Roux-en-Y gastric bypass: systematic review and Bayesian network meta-analysis comparing open, laparoscopic, and robotic approach. SurgObesRelat Dis. 2019 Jun;15(6):985–94. https://doi.org/10.1016/j.soard.2019.03.006. Epub 2019 Mar 20. PMID: 31104958.

• 3. Wang L, Yao L, Yan P, Xie D, Han C, Liu R, Yang K, Guo T, Tian L. Robotic Versus Laparoscopic Roux-en-Y Gastric Bypass for Morbid Obesity: a Systematic Review and Meta-Analysis. Obes Surg. 2018 Nov;28(11):3691–700. https://doi.org/10.1007/s11695-018-3458-7. PMID: 30178157.

• 4. Economopoulos KP, Theocharidis V, McKenzie TJ, Sergentanis TN, Psaltopoulou T. Robotic vs. Laparoscopic Roux-En-Y Gastric Bypass: a Systematic Review and Meta-Analysis. Obes Surg. 2015 Nov;25(11):2180–9. https://doi.org/10.1007/s11695-015-1870-9. PMID: 26344797.

• 5. Bailey JG, Hayden JA, Davis PJ, Liu RY, Haardt D, Ellsmere J. Robotic versus laparoscopic Roux-en-Y gastric bypass (RYGB) in obese adults ages 18 to 65 years: a systematic review and economic analysis. SurgEndosc. 2014 Feb;28(2):414–26. https://doi.org/10.1007/s00464-013-3217-8. Epub 2013 Oct 3. PMID: 24196545.

• 6. Hagen ME, Jung MK, Fakhro J, Buchs NC, Buehler L, Mendoza JM, Morel P. Robotic versus laparoscopic stapling during robotic Roux-en-Y gastric bypass surgery: a case-matched analysis of costs and clinical outcomes. SurgEndosc. 2018 Jan;32(1):472–7. https://doi.org/10.1007/s00464-017-5707-6. Epub 2017 Jul 19. PMID: 28726136.

• 7. Beckmann JH, Kersebaum JN, von Schönfels W, Becker T, Schafmayer C, Egberts JH. Use of barbed sutures in robotic bariatric bypass surgery: a single-center case series. BMC Surg. 2019 Jul 23;19(1):97. https://doi.org/10.1186/s12893-019-0563-z. PMID: 31337375; PMCID: PMC6651907.

• 8. Al Harakeh AB, Kallies KJ, Borgert AJ, Kothari SN. Bowel obstruction rates in antecolic/antegastric versus retrocolic/retrogastric Roux limb gastric bypass: a meta-analysis. Surg ObesRelat Dis. 2016 Jan;12(1):194–8. https://doi.org/10.1016/j.soard.2015.02.004. Epub 2015 Feb 11. PMID: 26003892.

• 9. Falvo AM, Vacharathit V, Dove J, Fluck M, Daouadi M, Gabrielsen J, Horsley R, Petrick A, Parker DM. A 3-Year MBSAQIP propensity-matched analysis of Roux-en-Y gastric bypass with concomitant cholecystectomy: Is the robotic or laparoscopic approach preferred? SurgEndosc. 2020 Sep 21. https://doi.org/10.1007/s00464-020-07939-0. Epub ahead of print. PMID: 32959181.

• 10. Tønnesen CJ, Young J, Glomsaker T, Mala T, Løberg M, Bretthauer M, Refsum E, Aabakken L. Laparoscopy-assisted versus balloon enteroscopy-assisted ERCP after Roux-en-Y gastric bypass. Endoscopy. 2020 Aug;52(8):654–61. https://doi.org/10.1055/a-1139-9313. Epub 2020 Apr 21. PMID: 32316042.

• 11. Magouliotis DE, Tasiopoulou VS, Tzovaras G. One Anastomosis Gastric Bypass Versus Roux-en-Y Gastric Bypass for Morbid Obesity: an Updated Meta-Analysis. Obes Surg. 2019 Sep;29(9):2721–30. https://doi.org/10.1007/s11695-019-04005-0. PMID: 31172454.

• 12. Landreneau JP, Strong AT, Rodriguez JH, Aleassa EM, Aminian A, Brethauer S, Schauer PR, Kroh MD. Conversion of Sleeve Gastrectomy to Roux-en-Y Gastric Bypass. Obes Surg. 2018 Dec;28(12):3843–50. https://doi.org/10.1007/s11695-018-3435-1. PMID: 30094577.