Introduction

Proximal Roux-en-Y gastric bypass is the most frequently performed bariatric procedure in Europe [1, 2] and is a standard procedure in the surgical treatment of obesity, particularly in the presence of type 2 diabetes or gastroesophageal reflux disease [1, 3]. The laparoscopic technique [4] is well-established and clearly superior to the open procedure [5]. The operation is safe with low complication rates but technically challenging with a relatively flat learning curve of at least 100 [6] to 500 [7] procedures. In the expectation of overcoming the limitations of laparoscopy and shortening the learning curve [8], the surgical robot was implemented in bariatric surgery.

In 1998, a bariatric operation using a surgical robot was performed for the first time for the implantation of a gastric band [9]. The first robot-assisted Roux-en-Y gastric bypass (RRYGB) followed in 2001 [10]. Since then, various studies have shown that RRYGB is safe and efficient but requires longer operating times and higher costs than laparoscopic RYGB (LRYGB) [11, 12]. Other studies reported lower complication rates, a lower number of revision procedures, and a steeper learning curve with RRYGB [8, 13,14,15,16,17], although some studies reported higher complication rates [18,19,20]. Meta-analyses have confirmed the lower incidence of complications, longer surgery times, and higher costs associated with RRYGB but criticized the relatively low quality of the existing studies and the lack of large randomized controlled trials [21, 22]. US registry data indicate the increasing prevalence of RRYGB, which comprised 5.8% (n = 2282) of all RYGB procedures in 2016 (versus 39,425 LRYGB procedures), with comparable complication rates but longer surgery time (138 min) versus LRYGB (108 min) [23]. Despite the increase, it remains controversial whether the use of the robot in bariatric surgery is justified.

We present the largest German series of RRYGB procedures using the da Vinci **, trocars, and instruments of €2000 [35]. With our current reduction in operative times with RRYGB and the corresponding deduction of a minimum of 30 min × €15/min, we assume additional costs of approx. €1500 per RRYGB case. It remains questionable whether these costs are economically profitable by avoiding complications, which has been postulated [14]. It also remains questionable whether advertising effects will recoup the economic costs, which has also been suggested [16]. To reduce costs effectively, an interdisciplinary setting with the highest possible utilization of the system is required, to minimize the high maintenance costs [36].

A possible weakness of the present paper lies in the selection type and in the temporal divergence of the two groups. While laparoscopic procedures were mainly performed between 2016 and 2017, most of the robotic operations took place around 2018. The cohorts are largely comparable. The differences observed in EOSS tended to favor the LRYGB group. The operations were performed by various surgeons, all of whom already had bariatric experience. At the beginning of the study, most of the bariatric surgeons involved were still within the learning curve of an LRYGB as a possible explanation for increased complication rates and operative times. Thus, the conclusions of this paper are valid for bariatric surgeons with limited laparoscopic RYGB experience. The experience with the da Vinci system was limited to bariatric procedures with the Si system before da Vinci ** was introduced. The entire learning curve with the ** System can be found in the robotic group. While the latter would benefit the laparoscopic cohort, the overall experience with the procedure gained in laparoscopic RYGB would favor the robotic cohort. The strength of the study lies in the comparable surgical techniques using linear stapler anastomoses. The study provides a detailed picture with a complete 30-day follow-up rate.

Conclusion

In our experience, robotic RYGB has proven to be safe and efficient. In case of still limited expertise with laparoscopic RYGB procedures, using a robotic system may result in lower complication rates and shorter operative times than laparoscopic RYGB. Whether the benefits outweigh the additional costs required for RRYGB remains to be evaluated. Further studies with higher evidence level are necessary to confirm our results.