Robotic Gastrectomy With a Novel 5th Arm - an International Multicenter Pilot Study

Laparoscopic surgery is a well-established minimally invasive surgery (MIS) technique, and is currently the standard treatment approaches for various benign and malignant surgical diseases of the abdomen [1]. In comparison with traditional open surgery, where a large surgical incision is made, laparoscopic surgery uses three to six small (0.5-1.5 cm) incisions to complete similar operative procedures. Based on numerous randomized controlled trials, minimally invasive surgeries have been proven to be beneficial in reducing patient trauma and morbidity, expediting postoperative recovery, and improving cosmesis when compared with open surgery [2,3].

The quest to develop precise and safe MIS in order to further reduce surgical trauma and improve patients' outcome still remains robust. Robotic technologies are expected to overcome the technical challenges associated with conventional laparoscopic surgery, including the limitation in degree of freedom associated with conventional laparoscopic instruments as well as lack of precision for dissection. The da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA, USA) was initially developed in 1999 to address the technical disadvantages of conventional laparoscopic surgery in terms of visualization and maneuverability. The robotic system provides a stable camera platform with magnified 3D view, and intuitively transfers movements from the handle to the tip of the instrument with tremor filtering. Dexterity is enhanced via EndoWrist technology, returning seven degrees of freedom to the surgeon [4].

Despite its technical advantages, robotic surgery has always been criticized for being highly expensive, which has limited its accessibility and wider applications [5,6]. The current da Vinci Surgical System from Intuitive Surgical has high performance with excellent quality. However, the high cost for each robotic surgical procedure has imposed major financial impact to patients and hospitals. In order to provide a cost-effective solution, introduction of new robotic systems with similar quality of performance and lower instalment /maintenance costs is necessary.

Robotic Surgery in Gastric Cancer Surgery Laparoscopic surgery, is widely accepted as curative treatment for gastric cancer (GC). Several multicentre randomized clinical trials (RCTs) have reported lower rates of postoperative complications in patients who underwent laparoscopic gastrectomy (LG) compared with open gastrectomy, but with similar long-term prognosis between them [7-11]. Laparoscopic gastrectomy still has several drawbacks, however, including the limited range of movement, amplification of operator hand tremors, and inconvenient surgical positioning [12-16]. Specifically, for D2 lymphadenectomy, laparoscopic instruments lack the dexterity during supra-pancreatic dissection leading to pancreatic injury [12-13].

With the technical advantages described above, robotic gastrectomy (RG) may therefore overcome some of the drawbacks associated with LG. An RCT from China has shown that RG is associated with better short term outcomes such as lower morbidity rate, faster recovery, milder inflammatory responses, and improved lymphadenectomy [17]. The 3-year oncological outcome of the same trial also showed that RG has improved 3-year DFS and cumulative recurrence rate [18]. Another RCT from Japan reported a significantly lower postoperative surgical complications of Clavien-Dindo Grade II or higher although did not show difference in intra-abdominal infectious complications [19].