Long-Term Outcomes and Safety of Robotic Bariatric Surgery

Abstract

Background:

Bariatric surgery (BS) is the most effective treatment for sustained weight loss and improvement of obesity-related comorbidities. Robotic BS (RBS) offers enhanced precision and ergonomics; however, local data remain limited.

Methods:

This retrospective real-world study included consecutive adults (≥18 years) who underwent single-surgeon robotic-assisted primary BS using the da Vinci® Surgical System (October 2012–December 2024), with complete perioperative and follow-up data.

Results:

A total of 545 patients were analyzed with a mean age of 42.98 ± 11.15 years and a mean body mass index (BMI) of 44.55 ± 6.66 kg/m²). Sleeve gastrectomy (SG) was the most common procedure (72.48%), followed by Roux-en-Y gastric bypass (RYGB, 17.61%) and one-anastomosis gastric bypass (OAGB, 9.91%). Mean docking and operative times were 6.25 ± 2.29 and 99.84 ± 29.21 minutes, respectively. Intraoperative events were infrequent (console-related 2.57%, bedside-related 4.04%, instrument-related 3.12%), with no conversions. Mean intensive care unit (ICU) and hospital stays were 0.25 ± 0.45 and 2.42 ± 0.56 days. Thirty-day complications occurred in 2.02% of patients, comprising grade I (1.10%), grade II (0.73%), and grade III (0.18%) events. Between 1 month and 1 year, 1.28% experienced minor (grade I) complications. At 1 year, mean BMI decreased to 32.68 ± 4.02 kg/m², with no mortality. Outcomes in patients with BMI ≥ 50 kg/m² were comparable, supporting the safety and feasibility of RBS in grade IV obesity.

Conclusions:

RBS proved safe, efficient, and effective, with low complications and consistent outcomes, supporting its use for obesity management in high-volume centers.

INTRODUCTION

Obesity has emerged as a global epidemic, with its prevalence more than doubling since 1980 according to World Health Organization (WHO) estimates. In 2016, over 1.9 billion adults were overweight and more than 650 million were obese.^1,2 The World Obesity Atlas 2023 projects that by 2035, obesity will affect over four billion individuals, approximately 51% of the global population, resulting in an estimated annual economic burden approaching USD 4 trillion.³ These alarming trends underscore the escalating public health and socioeconomic challenges associated with obesity worldwide.

BS is now a principal therapeutic option for obesity and associated metabolic disorders, reflecting its escalating global burden.⁴ According to the American Society for Metabolic and Bariatric Surgery (ASMBS), sleeve gastrectomy (SG) and Roux-en-Y gastric bypass (RYGB) constitute approximately 59.4% and 17.8% of all bariatric procedures in the United States, respectively.³ A 2018 global survey by the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) identified one anastomosis gastric bypass (OAGB) as the third most commonly performed bariatric procedure worldwide.⁵ Robotic bariatric surgery (RBS) has undergone a transformative evolution over the past two decades, reshaping the landscape of minimally invasive metabolic surgery. The first robotic-assisted laparoscopic gastric banding, performed by Drs. Cadiere and Himpens in Belgium in 1998, marked a pivotal milestone in the evolution of RBS.^6,7 Subsequent technological advancements have markedly enhanced the precision, dexterity, and efficiency of robotic systems, solidifying their role in minimally invasive BS.⁸ Analysis of over one million cases from the 2015–2020 Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP) Participant Use Data File (PUF) revealed a notable rise in robotic procedures, with robotic RYGB (RRYGB) increasing from 6.8% to 16.7% and robotic SG (RSG) from 6.0% to 17.2% during this period.^9,10 Interestingly, the increasing adoption of robotic platforms appears to favor RYGB over SG, likely driven by its significantly lower overall morbidity and bleeding rates, with comparable leak rates.¹¹ This trend reflects growing clinical acceptance and continued innovation driving broader adoption of robotic platforms in BS.¹⁰ RBS has emerged as a safe and effective alternative to laparoscopic BS (LBS), offering potential advantages such as reduced blood loss, decreased postoperative pain, lower wound infection rates, and lower perioperative morbidity.^12,13 We started performing RBS in 2012, with outcomes systematically documented over the subsequent 12 years. The 3rd-generation da Vinci Si system was employed until Jun 2021, followed by the 4th-generation da Vinci Xi platform. From December 2022, robotic staplers (SureForm Staplers) were integrated into the workflow; notably, the 60-mm SureForm stapler for the da Vinci Xi received Food and Drug Administration (FDA) approval in 2018.^10,13 The incorporation of these technological advancements, coupled with improved ergonomics and increased experience of operating team helped optimize surgical precision and outcomes.^14,15 The present study evaluates safety and efficacy of RBS based on a single surgeon 12 years’ experience.

MATERIALS AND METHODS

Preoperative Characteristics of the Study Population

This study employed a retrospective design and analyzed real-world data from one surgical team operating in tertiary care center. The cohort comprised consecutive adult patients (aged ≥18 years) who underwent robotic-assisted primary BS using the da Vinci® Surgical System between October 2012 and December 2024. Patients were selected for inclusion only if their medical records contained complete information on preoperative characteristics, intraoperative parameters, and postoperative outcomes. All procedures were carried out by a single surgeon utilizing standardized operative protocols and institutional guidelines to ensure procedural consistency. Cases involving revisional BS or incomplete datasets were excluded from analysis. The study adhered to the ethical principles outlined in the Declaration of Helsinki and complied with the International Council for Harmonization–Good Clinical Practice (ICH-GCP) standards.

Data Collection and Analysis

Anonymized patient information was obtained from institutional medical records. Preoperative parameters included demographic details, relevant medical history, procedure type, and American Society of Anesthesiologists (ASA) classification. Perioperative data encompassed docking and operative times, the type of stapling systems and cartridges utilized, intraoperative events, blood transfusion requirements, time to first and second anastomosis, intensive care unit (ICU) and total hospital stay, intrahospital complications, and any conversions. Postoperative follow-up data were categorized as short-term and long-term outcomes, capturing complications occurring within one month, between 1 and 3 months, between 3 months and 1 year, and beyond 1 year after surgery. Additional endpoints included body mass index (BMI) at 1 year postoperatively and all-cause mortality. All information was compiled using a uniform data collection form to maintain consistency across records. Continuous variables were described as means with standard deviations (SDs), and categorical variables as frequencies and percentages. Statistical analyses were conducted using Stata software, version 16.0 (StataCorp LLC, Texas, USA).

Surgical Technique

Port position

The port positions remained identical for RSG, RRYGB, and robotic OAGB (ROAGB), as illustrated in Figures 1 and 2. Pneumoperitoneum was established at Palmer’s point, and the camera port (C) was inserted slightly left of the midline, approximately 20 cm below the xiphisternum. Under direct visualization, additional robotic ports were placed in an arc configuration 18–20 cm from the xiphisternum: R1 in the left midclavicular line, R2 in the right midclavicular line, R3 in the left anterior axillary line at the level of the camera port, and an assistant port between C and R2, maintaining at least 8 cm spacing between ports. A 12/15-mm assistant port was placed when laparoscopic staplers were used, whereas a 5/10-mm assistant port was placed when SureForm staplers were used. R2 becomes the 12 mm da Vinci® stapling port when SureForm staplers are used.

Figure 1.

Port position for robotic bariatric surgery.

Figure 2.

Ports after docking.

A 5-mm subxiphoid Nathanson retractor was inserted to elevate the left lobe of the liver. The operating room configuration varied according to the robotic platform employed. With the da Vinci Si system, the patient cart was docked parallel to the table on the left side to ensure adequate clearance of the robotic arms. In contrast, the da Vinci Xi platform, with its rotatable boom, allowed flexible docking from either side of the patient, overcoming the spatial limitations associated with earlier systems.

RSG

RSG was performed using the da Vinci® Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) as illustrated in Figure 3. Patients were positioned supine with both arms abducted and placed in a 40° reverse Trendelenburg position. Ports were placed as described. After docking, a 38 Fr gastric calibration tube (GCT) was introduced for gastric decompression and sizing. Gastrolysis was initiated 2–3 cm proximal to the pylorus along the greater curvature using a robotic energy device (ultrasonic shears or vessel sealer), dividing the short gastric vessels and fully mobilizing the fundus to the left crus of the diaphragm. Once the fundus was completely mobilized, gastric transection was performed alongside the GCT using articulating laparoscopic or SureForm staplers. Typically, a black cartridge was used for the initial firing near the antrum, followed sequentially by blue or purple reloads to achieve a uniform, tubular sleeve without twisting or narrowing. The staple line was reinforced with a continuous 3-0 barbed suture to enhance hemostasis and reduce the risk of leaks. The integrity of the sleeve was verified intraoperatively using endoscopic and saline leak testing till 2022. A routine leak test was stopped after 2022. After confirming hemostasis and sleeve configuration, the specimen was extracted, and all port sites were closed in layers.

Figure 3.

RSG surgical technique. Gastrolysis during sleeve gastrectomy using vessel sealer (A); gastric sleeve creation using sureform stapler (B); staple line imbrication using barbed suture (C).

RRYGB

RRYGB procedures were performed using the da Vinci® Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) as illustrated in Figure 4. Patients were placed in the supine position with both arms abducted and a 20° reverse Trendelenburg tilt. Following port placement, diagnostic laparoscopy was performed, and the ligament of Treitz was identified. The biliopancreatic limb (75–100 cm) and Roux limb (100 cm) were measured and temporarily hitched along the greater curvature near the gastric antrum. After docking the robot, a small gastric pouch (approximately 20–30 mL) was created following entry into the lesser sac using a perigastric approach. A 38 Fr GCT was introduced to standardize pouch sizing, and sequential horizontal and vertical stapler firings were performed over the calibrated tube. In the Si system, laparoscopic staplers were operated via the assistant port, while in the Xi system, either laparoscopic or SureForm staplers were used. A loop gastrojejunostomy was constructed as a four-layer hand-sewn anastomosis using barbed sutures, or with a linear stapler. The jejunum was then divided to convert the loop configuration into Roux-en-Y. The jejunojejunostomy was created in a side-to-side fashion using a 60-mm stapler. Mesenteric and Petersen’s defects were routinely closed with nonabsorbable sutures to prevent internal herniation. Anastomotic integrity was checked in selective cases using endoscopic leak testing. Port sites were closed after ensuring hemostasis and desufflation.

Figure 4.

RRYGB surgical technique. Hand sewn gastro-jejunostomy during RYGB (A); stapled jejuno-jejunostomy during RYGB (B); mesenteric defect closure during RYGB (C).

ROAGB

ROAGB was performed under general anesthesia with the patient positioned supine in a reverse Trendelenburg tilt as illustrated in Figure 5. After the standard port placement, diagnostic laparoscopy was done to assess the abdominal cavity. A jejunal loop, 150–200 cm distal to the ligament of Treitz, was identified and brought up antecolic and antegastric for creation of an isoperistaltic gastrojejunostomy. The loop was temporarily hitched to the gastric antrum before docking the robot, which was performed from either side of the patient depending on operative ergonomics. The lesser sac was entered along the lesser curvature of the stomach, and a 38 Fr GCT was introduced to standardize pouch sizing. A tubular gastric pouch of approximately 60–80 mL was created using sequential 60-mm stapler firings, starting 2 cm distal to the incisura angularis and extending toward the angle of His. The prepared jejunal loop was then anastomosed to the distal aspect of the gastric pouch. The gastrojejunostomy was completed either by hand-sewn four-layered closure using barbed sutures or, alternatively, with a stapled anastomosis employing a 60-mm cartridge. A selective check endoscopy was done to assess the gastric pouch and gastrojejunostomy. Meticulous hemostasis was confirmed prior to undocking. Finally, the ports were removed under direct vision, and port-site closure was performed in layers.

Figure 5.

ROAGB surgical technique. Gastric pouch creation during OAGB using sureform stapler (A); gastro-jejunostomy using sureform stapler during OAGB (B); hand sewn GJ during OAGB (C).

The initial cases in this series were performed using the da Vinci S system (2nd-generation). From 2012 onwards, the da Vinci Si system (3rd-generation) was adopted. Both the S and Si platforms lacked integrated stapling capabilities, necessitating stapling by the bedside assistant through a 12-mm trocar. Additionally, these systems utilized a 10-mm endoscope and required repositioning of the patient cart based on the target anatomy. In early bariatric procedures, the patient cart was docked from the head end; however, this approach limited anesthetic access to the airway. To address this, the docking strategy was subsequently modified to a parallel approach from the left shoulder, which improved access for anesthesia management and facilitated intraoperative upper gastrointestinal endoscopy. Since 2021, the da Vinci Xi system (4th-generation) has been utilized. This platform introduced integrated SureForm stapling, allowing the console surgeon to directly control stapling, thereby enhancing surgical autonomy and efficiency. The boom-mounted design eliminated the need for patient cart repositioning and improved access around the head of the patient for the anesthesia team. The system also incorporates an 8-mm endoscope that can be interchanged across robotic arms, reducing port variability. Furthermore, longer instruments and enhanced multiquadrant access have improved procedural ergonomics, particularly in bariatric procedures such as gastric bypass, where both infracolic and supra-colic compartments can be addressed with a single docking. Notably, surgeon experience, institutional volume, and case complexity remain critical determinants of operative efficiency.

RESULTS

Demographic and Preoperative Characteristics

The demographic characteristics and preoperative variables of the study population are summarized in Table 1. A total of 545 patients who underwent RBS were included in this analysis. The mean age of the study population was 42.98 ± 11.15 years, with a nearly equal sex distribution (female: 52.29%; male: 47.71%). The mean preoperative BMI was 44.55 ± 6.66 kg/m², with 15.96% of patients classified as Grade IV obese (BMI ≥ 50 kg/m²). Among preoperative comorbidities, type 2 diabetes (45.14%), hypertension (40.55%), and obstructive sleep apnea (48.44%) were most prevalent, followed by osteo-articular disease (36.15%) and dyslipidemia (2.94%). Prior surgical history was reported in 13.39% of patients, while thromboembolic events (1.28%), immunosuppressive therapy (3.85%), and smoking history (3.12%) were relatively uncommon. Regarding the type of bariatric procedure performed, SG accounted for the majority (72.48%), followed by RYGB in 17.61% and OAGB in 9.91%. Most patients were classified as ASA grade III (90.09%), reflecting a higher-risk population.

Table 1.

Demographic and Preoperative Characteristics of the Study Population

Variable	N = 545
Age, mean ± SD, year	42.98 ± 11.15
Sex, n (%)
Female	285 (52.29)
Male	260 (47.71)
Weight, mean ± SD, kg	121.50 ± 23.08
BMI, mean ± SD, kg/m2	44.55 ± 6.66
BMI ≥50, n (%), kg/m2	87 (15.96)
Comorbidities, n (%)
Diabetes	246 (45.14)
Hypertension	221 (40.55)
Obstructive sleep apnea	264 (48.44)
Osteo-articular disease	197 (36.15)
Dyslipidemia	16 (2.94)
Previous surgery, n (%)	73 (13.39)
History of thromboembolic events, n (%)	7 (1.28)
Immunosuppression therapy, n (%)	21 (3.85)
Smoking history, n (%)	17 (3.12)
Type of MBS, n (%)
SG	395 (72.48)
RYGB	96 (17.61)
OAGB	54 (9.91)
ASA classification, n (%)
II	54 (9.91)
III	491 (90.09)

Abbreviations: ASA, American Society of Anesthesiologists; BMI, body-mass index; MBS, metabolic bariatric surgery; OAGB, one anastomosis gastric bypass; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy.

Perioperative Characteristics

The overall mean docking time and total operative time were 6.25 ± 2.29 minutes and 99.84 ± 29.21 minutes, respectively (Table 2). When assessed by procedure type, SG had a docking time of 6.39 ± 2.24 minutes and an operative time of 88.05 ± 13.33 minutes, while OAGB demonstrated the shortest docking time at 3.96 ± 1.09 minutes with an operative time of 88.70 ± 11.82 minutes. Notably, RYGB required a comparable docking time (6.94 ± 2.25 minutes) but a considerably longer operative duration of 154.64 ± 19.78 minutes, reflecting the increased technical complexity of this procedure. The most frequently used stapling systems were EndoGIA with Tri-Staple (41.47%) and Powered Echelon Flex with GST (38.90%), followed by SureForm 60 (14.68%). Intraoperative events were infrequent, with console-related events in 2.57%, bedside assistant-related in 4.04%, and instrument-related in 3.12% of cases. Notably, no conversions to laparoscopy or open surgery were reported.

Table 2.

Perioperative Characteristics of the Study Population

Variable	N = 545
Docking time, mean ± SD, minutes	6.25 ± 2.29
Operative time, mean ± SD, minutes	99.84 ± 29.21
Type of stapler used, n (%)
EndoGIA with Tri-Staple	226 (41.47)
Powered Echelon Flex with GST	212 (38.90)
SIGNIA with Tri-Staple 2.0	27 (4.95)
SureForm 60	80 (14.68)
Console-related events, n (%)	14 (2.57)
Bedside assistant-related events, n (%)	22 (4.04)
Instrument-related events, n (%)	17 (3.12)
Conversion to laparoscopy, n (%)	0
Conversion to open, n (%)	0
Gastro-jejunal anastomosis type (RYGB^ + OAGB), n (%)
Hand-sewn	79 (52.67)
Linear stapler	70 (46.67)
Jejuno-jejunal anastomosis type (RYGB^), n (%)
Hand-sewn	1 (1.04)
Linear stapler	94 (97.92)
Time to first anastomosis, mean ± SD, minutes	61.23 ± 16.88
Time to second anastomosis, mean ± SD, minutes	130.47 ± 19.84
Closure of mesenteric defects (RYGB), n (%)	96 (100)
Staple line reinforcement (SG^), n (%)	393 (99.49)
Intraoperative blood transfusion, n (%)	0
Intra-abdominal drain used, n (%)	55 (10.09)
Length of ICU stay, mean ± SD, days	0.25 ± 0.45
Number of days in the ICU, n (%)
0	412 (75.60)
1	129 (23.67)
2	4 (0.73)
Length of hospital stay, mean ± SD, days	2.42 ± 0.56
Postoperative blood transfusion, n (%)	7 (1.28)
Complications before discharge, n (%)	13 (2.39)
Days since surgery, mean ± SD, days	1.15 ± 1.10
Clavien Dindo classification, n (%)
Grade I	7 (1.28)
Grade II	6 (1.10)
Death until discharge, n (%)	0

^Data on anastomosis type for 1 RYGB case and staple-line reinforcement status for 2 SG cases was unavailable.

Abbreviations: RYGB, Roux-en-Y gastric bypass; SD, standard deviation; SG, sleeve gastrectomy.

Among RYGB procedures, linear staplers were used for the gastrojejunostomy in 46.67% and jejunojejunostomy in 97.92% of cases, while hand-sewn techniques were frequently employed. The mean times to first and second anastomoses were 61.23 ± 16.88 minutes and 130.47 ± 19.84 minutes, respectively. Staple-line reinforcement was performed in 99.49% of SG cases, and mesenteric defects were closed in all RYGB procedures. No patient required intraoperative transfusion, and only 10.09% patients required intra-abdominal drain placement. The mean ICU stay was 0.25 ± 0.45 days, with 75.6% of patients not requiring ICU admission. The mean total hospital stay was 2.42 ± 0.56 days. Postoperative transfusions were required in 1.28% of patients. The overall complication rate before discharge was 2.39%, predominantly Clavien-Dindo grade I (1.28%) and grade II (1.10%), with no in-hospital mortality.

Short- and Long-Term Postoperative Outcomes

The complete one-year follow-up data for BMI were available for all patients, whereas complication data were available for 307 patients. During follow-up, postoperative complications remained low across all time points (Table 3). Complications within one month of discharge occurred in 2.02% of patients, comprising Clavien–Dindo grade I (1.10%), grade II (0.73%), and grade III (0.18%) events. Notably, the sole grade III complication, a gastric sleeve leak occurred within the first 20 cases. Between one month and 1 year postoperatively, 7 patients (1.28%) experienced complications, all of which were classified as Clavien–Dindo grade I. The mean BMI at one-year postsurgery was 32.68 ± 4.02 kg/m², reflecting significant postoperative weight reduction. No mortality was reported during the follow-up period. At baseline, patients undergoing SG (N = 395) and RYGB (N = 96) had comparable mean BMI values (44.22 ± 6.37 and 43.43 ± 5.20, respectively), whereas the OAGB group (N = 54) demonstrated a lower but highly variable baseline BMI (33.00 ± 19.54), indicating greater heterogeneity in this cohort. At 1-year follow-up, all 3 groups showed marked reductions in BMI. The mean BMI decreased to 32.64 ± 3.97 in the SG group and 32.24 ± 3.10 in the RYGB group, indicating broadly comparable postoperative BMI profiles. In contrast, the OAGB group achieved the lowest mean BMI at 1 year, at 24.39 ± 11.67. The mean reduction in BMI was 11.58 ± 4.50 in the SG group and 11.19 ± 4.07 in the RYGB group, with no statistically significant difference between the two procedures (P = .4384), suggesting a similar magnitude of weight loss. The OAGB group, however, demonstrated a greater mean BMI reduction of 14.05 ± 5.22, which was statistically significant compared with both SG (P < .05) and RYGB (P < .05), indicating a potentially greater weight-loss effect. Nevertheless, this finding should be interpreted cautiously in view of the smaller sample size and the considerable variability in baseline BMI within the OAGB cohort.

Table 3.

Short- and Long-Term Postoperative Outcomes of the Study Population

Variable	N = 545
Complications (within 1 month from discharge), n (%)	11 (2.02)
Days since surgery, mean ± SD, days	10.60 ± 6.94
Clavien Dindo classification, n (%)
Grade I	6 (1.10)
Grade II	4 (0.73)
Grade III	1 (0.18)
Complications (between 1 month to 1 year), n (%)	7 (1.28)
Clavien Dindo classification, n (%)
Grade I	7 (1.28)
BMI at 1 year postoperatively, mean ± SD, kg/m2	32.68 ± 4.02
Mortality, n (%)	0

Abbreviations: BMI, body mass index; SD, standard deviation.

Outcomes in Grade IV Obese Subgroup (BMI ≥ 50 kg/m²)

The outcomes in the Grade IV obese subgroup (BMI ≥ 50 kg/m²) are summarized in Table 4. Among the 87 patients with BMI ≥50 kg/m², the mean age was 41.44 ± 12.05 years. SG remained the predominant procedure (68.97%), followed by OAGB (21.84%) and RYGB (9.20%). The mean docking and operative times were 5.99 ± 2.37 minutes and 92.63 ± 22.71 minutes, respectively. Intraoperative events were low, with console-related (4.60%), bedside assistant-related (2.30%), and instrument-related (3.45%) events, none necessitating conversion or transfusion. The mean ICU and hospital stays were 0.26 ± 0.49 days and 2.31 ± 0.57 days, respectively. Although intraoperative transfusions were not required, postoperative transfusions occurred in 2.30% of patients. The complication rate before discharge was 3.45%, with a small number (2.30%) of late Clavien-Dindo class 1 complications reported between one month and 1 year. The mean BMI at 1 year was 37.76 ± 4.70 kg/m², which, although higher than the overall cohort, indicates substantial weight reduction and favorable postoperative outcomes in this Grade IV obese subgroup.

Table 4.

Outcomes in Grade IV Obese Subgroup (BMI ≥ 50 kg/m²)

Variable	N = 87
Age, mean ± SD, years	41.44 ± 12.05
Type of MBS, n (%)
SG	60 (68.97)
RYGB	8 (9.20)
OAGB	19 (21.84)
Docking time, mean ± SD, minutes	5.99 ± 2.37
Operative time, mean ± SD, minutes	92.63 ± 22.71
Console-related events, n (%)	4 (4.60)
Bedside assistant-related events, n (%)	2 (2.30)
Instrument-related events, n (%)	3 (3.45)
Time to first anastomosis, mean ± SD, minutes	57.00 ± 15.67
Time to second anastomosis, mean ± SD, minutes	121.63 ± 21.31
Intraoperative blood transfusion, n (%)	0
Length of ICU stay, mean ± SD, days	0.26 ± 0.49
Length of hospital stay, mean ± SD, days	2.31 ± 0.57
Postoperative blood transfusion, n (%)	2 (2.30)
Complications before discharge, n (%)	3 (3.45)
Complication within 1 month from discharge, n (%)	0
Complications (between 1 month to 1 year), n (%)	2 (2.30)
BMI at 1 year postoperatively, mean ± SD, kg/m2	37.76 ± 4.70

Abbreviations: BMI, body-mass index; MBS, metabolic bariatric surgery; OAGB, one anastomosis gastric bypass; RYGB, Roux-en-Y gastric bypass; SG, sleeve gastrectomy.

DISCUSSION

BS remains the most effective and widely accepted treatment for obesity, offering sustained metabolic benefits, improved longevity, reduced long-term healthcare costs, and significant enhancements in quality of life (QoL).^2,16 The operative complexity of these procedures may be partially alleviated through robotic assistance.¹⁷ Since the first robotic bariatric procedure in 1999 demonstrated the feasibility of this approach,⁶ robotic platforms have continued to evolve. Against this background, the present study evaluates short- and long-term outcomes of RBS, including OAGB, RYGB, and SG, within the local clinical setting.

The demographic and clinical characteristics of our cohort were broadly consistent with those reported in global literature.^{10,12,16,18–20} The cohort comprised a slightly higher proportion of female patients (52.29%), similar to prior reports where women constituted 79.7–80% of RRYGB and SG populations.^12,16 Obstructive sleep apnea (48.44%) was the most common comorbidity, followed by diabetes mellitus (45.17%), hypertension (40.55%), and osteo-articular disease (36.15%). These findings are comparable to earlier studies reporting hypertension, sleep apnea, and diabetes as the leading comorbidities in RYGB and SG patients.^12,16 Most patients were classified as ASA Grade III, aligning with previous observations that most bariatric candidates fall within this category.^10,12,16 In terms of procedure distribution, SG was the most frequently performed operation (72.48%), followed by RYGB (17.61%) and OAGB (9.91%). This trend parallels data from the MBSAQIP database (2015–2022), which identified SG as the predominant bariatric procedure (591,118 of 823,902 cases).¹¹ Similarly, recent analyses have shown a 1.96-fold rise in robotic BS, driven primarily by a 2.16-fold increase in SG and a 1.53-fold increase in RYGB.²¹

Intraoperative and postoperative metrics serve as key indicators of procedural safety and efficiency. In the present study, the mean docking time was 6.25 ± 2.29 minutes, and the mean operative time was 99.84 ± 29.21 minutes. Global benchmark data for primary RBS have reported operative time of 147.4 ± 48.1 minutes (low-risk) and 151.8 ± 54.8 minutes (high-risk) for RRYGB, and 74.7 ± 20.4 minutes (low-risk) and 85.7 ± 28.6 minutes (high-risk) for RSG.¹⁸ The operative times observed for RYGB (154.64 ± 19.78 minutes) and SG (88.05 ± 13.33 minutes) cohorts in our study are consistent with these previously reported findings. The first local study on ROAGB reported a mean operative time of 85 ± 35 minutes (range 50–130 minutes),²⁰ while another series involving 59 patients recorded a docking time of 6.5 minutes (range 3–16) and operative time of 54 minutes.²² The operative times observed for OAGB (88.70 ± 11.82 minutes) cohort in our study are consistent with these findings. Comparable operative times were observed in a study comparing early- and late-timeframe outcomes for RRYGB (158.52 ± 65.48 vs 158.85 ± 64.18 minutes) and SG (102.76 ± 45.67 vs 92.47 ± 41.70 minutes).¹⁰ In our series, we have oversewn the entire staple line after RSG, which adds 10–15 minutes in the operative duration. Analysis of 823,902 primary BS cases in the MBSAQIP database also demonstrated a steady decline in operative time with increasing experience, from 97.4 ± 40.8 to 78.9 ± 33.4 minutes for SG, and from 146.7 ± 59.9 to 135.0 ± 51.3 minutes for RYGB between 2015 and 2022.¹¹ These findings highlight the significant impact of the learning curve on operative efficiency.²³ Moreover, OAGB, characterized by a single anastomosis, is technically less demanding than RYGB, contributing to shorter operative times.^24,25

In the present study, most procedures employed the EndoGIA with Tri-Staple system, followed by the powered Echelon Flex with GST, SureForm 60, and SIGNIA with Tri-Staple 2.0. Comparable findings were reported in a previous study that analyzed stapler utilization patterns in RBS. In that analysis, for RYGB, the distribution included Powered Echelon Flex (37% in low-risk and 30% in high-risk cases), SureForm 60 (22% and 20.1%), EndoGIA (6.5% and 12.3%), and other staplers (34.5% and 37.6%); while for SG, SureForm 60 was used more frequently (80.2% and 75.8% in low- and high-risk cases, respectively), followed by Powered Echelon Flex, EndoGIA, and other types.¹⁰ The SureForm 60 stapler incorporates SmartFire™ technology, which continuously monitors tissue compression before and during firing, automatically adjusting to optimize staple line formation and minimize tissue trauma.¹⁰ Its 120° cone of articulation and 60° vertical range of motion allow superior access and precision, facilitating natural tissue alignment and reducing the need for external traction.²⁶ In the current cohort, the EndoGIA purple cartridge was the most frequently used (46.42%), followed by Echelon blue and SureForm blue cartridges. The outcomes were comparable between procedures performed using SureForm staplers and those using conventional laparoscopic staplers. Intraoperative complications serve as key indicators of surgical safety and procedural reliability. In the present study, the incidence of console-related (2.57%), bedside-assistant–related (4.04%), and instrument-related (3.12%) events was minimal. These findings align with previous analyses based on MBSAQIP data, which demonstrated similarly low rates of intra and postoperative complications in RBS compared with LBS.¹² Notably, overall leak rates in RBS have shown a declining trend, from 0.64% to 0.39% over time.²¹ Comparable safety outcomes were reported in studies on ROAGB, which documented no intraoperative or postoperative complications, and no anastomotic leaks.^20,22 Conversion to laparoscopy or open surgery is an important benchmark of procedural safety and surgeon expertise. In our series, no conversions were required, consistent with prior reports showing zero conversions to open surgery in RRYGB and SG, and only one laparoscopic conversion in RYGB.¹⁸ Similarly, studies have reported no conversions during ROAGB procedures.^20,22 A large MBSAQIP analysis of RRYGB (n = 6,566) and RSG (n = 17,215) further confirmed low conversion rates of 0.05% and 0.91%, respectively,¹⁶ reinforcing the safety and technical reliability of RBS.

The mean time to first and second anastomosis in our study was 61.23 ± 16.88 and 130.47 ± 19.84 minutes, respectively. A previous report documented a median interval of 56 minutes (interquartile range [IQR] 25–96) from skin incision to the first anastomosis and 88 minutes (IQR 45–131.2) to the second anastomosis.¹⁸ In the current series, mesenteric defect closure was performed in 100% of patients undergoing RYGB, while staple line reinforcement was achieved in 99.49% of those undergoing SG. By contrast, a prior multicenter analysis reported mesenteric defect closure rates of 87.1% (low-risk) and 89.4% (high-risk) RYGB cases, and substantially lower rates of staple line oversewing, 25.5% and 28.6% for low- and high-risk SG cases, respectively.¹⁸ These differences likely reflect variations in institutional practices, surgeon preference, and procedural standardization across centers. Notably, none of the patients in our cohort required intraoperative blood transfusion. This finding is consistent with a retrospective case–control analysis of the MBSAQIP database, which reported transfusion rates of 0.6% for RRYGB and 0.4% for RSG.¹² Similarly, another study comparing early and late time frames demonstrated consistently low transfusion rates for RYGB (0.6% vs 0.7%) and SG (0.5% vs 0.8%).¹⁰ In our series, only a small proportion of patients (1.28%) required postoperative transfusion, further underscoring the favorable hemostatic profile and safety of RBS. In the present study, postoperative recovery was favorable, with a mean ICU stay of 0.25 ± 0.45 days and a mean hospital stay of 2.42 ± 0.56 days. Most patients (75.60%) did not require ICU admission, while 23.67% stayed for one day and only 0.73% for two days. A retrospective case–control analysis from the MBSAQIP database reported comparable findings, with mean length of stay (LOS) of 2.1 ± 2.0 days for RRYGB and 1.8 ± 1.7 days for RSG.¹² Similarly, other studies have documented mean LOS of 1.2 days for RSG, 2.4 days for RRYGB,¹⁹ and 1.8 days (SD 2.6; range 1–4 days) for ROAGB.²⁰ A time-trend comparison also showed decreasing LOS over time, with early versus late time frame means of 2.13 ± 2.12 versus 1.69 ± 1.46 days for RYGB, and 1.76 ± 1.79 versus 1.36 ± 1.01 days for SG.¹⁰ In our series, no in-hospital mortality occurred, and postoperative complications prior to discharge were minimal (2.39%), underscoring the safety and efficiency of RBS in this cohort.

During both short-term and long-term follow-up, the results demonstrated a progressive decline in the proportion of patients experiencing complications. The incidence of complications was 2.02% within one month of discharge, and 1.28% between one month to 1 year. A previous study evaluating 30-day perioperative outcomes in the MBSAQIP database reported that most patients undergoing RSG (96.7%) and RYGB (95.7%) had no postoperative events, while only a small proportion experienced nonserious (SG: 1.9%; RYGB: 2.4%) or serious (SG: 1.3%; RYGB: 1.9%) complications.¹⁹ Furthermore, 1 year follow-up in the present study showed significant weight reduction, as reflected by a lower mean BMI of 32.68 ± 4.02 kg/m² at 1 year after BS. Importantly, no mortality was observed during the entire follow-up period. By contrast, a previous study reported 30-day mortality rates of 0.1% and 0.06% following RYGB and SG, respectively.¹² Across all follow-up intervals in the present study, complications were predominantly minor, corresponding to Clavien–Dindo grade I or II events. There was only one Clavien–Dindo grade III complication, a gastric sleeve leak that happened in the initial part of learning curve in 2013. The patient was managed with minimally invasive surgery and recovered well in one month. In more than 500 subsequent robotic bariatric cases, there has been no leak or Clavien–Dindo grade III complication.

In this study, we also assessed the demographic characteristics and clinical outcomes of the Grade IV obese subgroup (BMI ≥ 50 kg/m²). The mean age of patients in this cohort was comparable to that of the overall study population. Similar to the overall cohort, SG was the predominant procedure performed, with relatively fewer patients undergoing RYGB. In our study, the docking and total operative times in the BMI ≥ 50 kg/m² group were slightly lower than those observed in the overall population, though earlier reports have found no significant differences in operative time between BMI ≥ 50 kg/m² and lower BMI groups.²³ The overall incidence of console-related, bedside assistant-related, and instrument-related intraoperative events was comparable in patients with BMI ≥ 50 kg/m², consistent with earlier reports that demonstrated no significant difference in intra or postoperative complication rates between patients with BMI ≥ 50 kg/m² and those with lower BMI values.²³ The duration of ICU and overall hospital stay remained comparable to the overall study population. Consistent with the overall cohort, no patients in the BMI ≥50 kg/m² group required intraoperative blood transfusion. However, a higher proportion of patients in this subgroup required postoperative transfusions. Additionally, the incidence of complications before discharge, between one month to 1 year was higher among patients with BMI ≥ 50 kg/m², although they were all Clavien–Dindo grade class I complications. As expected, their mean BMI at 1 year postoperatively remained higher than that of the overall population. The comparable outcomes observed in the BMI ≥ 50 kg/m² subgroup in our practice further support the feasibility and safety of RBS in patients with Grade IV obesity.

CONCLUSIONS

In conclusion, this real-world analysis demonstrates that RBS is a safe, feasible, and effective treatment modality. The procedure was associated with low perioperative morbidity, minimal complication rates, short hospital stays, and significant postoperative weight reduction. Comparable outcomes in patients with Grade IV obesity (BMI ≥ 50 kg/m²) further highlight the utility of RBS in high-risk populations. These findings underscore the importance of surgical expertise, standardized protocols, and structured robotic surgery techniques in optimizing outcomes. Larger, prospective multicenter studies with extended follow-up are warranted to validate long-term metabolic, quality-of-life, and cost-effectiveness outcomes.

Strengths and Limitations

This study possesses several noteworthy strengths and certain limitations that warrant consideration. The inclusion of a large real-world cohort under standardized protocols strengthens the reliability and external relevance of the findings. All procedures were performed by a single experienced surgeon, thereby minimizing interoperator variability and ensuring technical consistency. Comprehensive perioperative documentation enabled detailed evaluation of intraoperative efficiency, complication profiles, and recovery parameters. The dedicated analysis of the Grade IV obese subgroup (BMI ≥ 50 kg/m²) further adds valuable insight into an underrepresented yet clinically challenging population. A key limitation of this study is its retrospective, single-center design, which restricts causal inference and limits the generalizability of the findings to broader, more diverse clinical settings. Additionally, the single-surgeon experience, while ensuring procedural consistency, may further constrain external applicability. The lack of a comparative laparoscopic or open surgery cohort precludes direct assessment of relative advantages.