When considering the safety and feasibility of LG, it is vital to assess the risks of POPF formation. PF after gastrectomy is thought to be caused by intraoperative injury to the pancreas. There are several possible causes of pancreatic injury during LG, including thermal injury from energy devices, compression from forceps, and accidental injury from anatomical variations or fatty pancreas [6, 7, 20, 34–37]. Among them, heat injury caused by an ultrasonic device is a major cause of pancreatic damage during LG [6, 34, 38–40]. In this retrospective study, we demonstrated that LDG with peripancreatic lymphadenectomy using ABD was associated with a lower rate of POPF and morbidity than that using a USAD for gastric cancer surgery. The incidence of clinically relevant POPF (CD ≥ II, International Study Group on Pancreatic Fistula grade ≥ B) of 0.8% in the ABD group was significantly lower than that of 9.2% in the USAD group. These results are comparable to those reported in a recent study of laparoscopic surgery performed at a high-volume center in Japan, which found a 1.0%-8.9% incidence of pancreatic fistula [5–8, 10, 11]. Other advantages of an ABD included a lower overall morbidity rate, more lymph nodes retrieved, and a shorter hospital stay. We also revealed in multivariate analysis of a PSM cohort that only the usage of a USAD was a significant independent risk factor for POPF in LDG.
ABD create a vessel seal by applying bipolar electrosurgical radiofrequency energy to vessels interposed between the jaws of the device [15]. In contrast, USAD use high-frequency mechanical energy to disrupt hydrogen bonds in tissues and denature proteins [14]. Each device has its own advantages and disadvantages due to their different thermal profiles and different sealing and cutting mechanisms. We previously reported that repeated dissection of energy devices with minimal cooling time results in high blade and jaw temperatures proportional to the incision distance. In particular, the USAD with partial tissue bite showed a significantly higher temperatures at the blade (341 ± 28.3°C) than that with the ABD (95.6 ± 5.5°C).[20] Due to the relatively low temperature of the activated blade and limited lateral thermal spread (0.9 mm beyond the tissue within the jaws), surgeons can use an ABD to dissect lymph nodes close to the pancreas and blood vessels, thereby minimizing the risk of damaging delicate adjacent structures while ensuring that the target lymph node can be completely removed [15, 20]. In addition, compared to a USAD, an ABD is more effective at achieving hemostasis and produces less surgical smoke and mist, as shown by the present results and previous reports, thereby improving the surgical visibility and lymph node clearance [21, 22]. However, another author believed that an ABD was not suitable for the precise surgical maneuvers required for operations such as gastrectomy with lymph node dissection for gastric cancer [23]. As reported earlier, an ABD requires some technical proficiency but can be used to perform definitive lymph node dissection more safely than a USAD [21]. Regardless of which energy device is used, surgeons should understand the thermal profile of the device and avoid inappropriate activation during suprapancreatic lymph node dissection in order to prevent thermal injury to the pancreas in LDG.
There have been many reports comparing the outcomes of procedures using ABD with those of conventional surgery for various surgical procedures [22, 23, 41, 42]. However, only a limited number of studies have compared the surgical outcomes of ABD and USAD. No significant difference in short-term surgical results between ABD and USAD was reported in laparoscopic colorectal resection, laparoscopic sleeve gastrectomy, or Roux-en-Y gastric bypass [43–45]. In thyroidectomy, a previous study found no marked difference between the ABD and USAD groups in the efficacy or surgical outcomes of total thyroidectomy [18]. Another group reported that an ABD was inferior to a USAD in terms of the operative time [46]. Yet, Kim et al. reported that in LDG with extended lymph node resection among 186 patients with gastric cancer, the bipolar device had advantages over the USAD with regard to operative time, degree of postoperative pain, time for drain removal, and length of hospital stay [47]. However, their study did not show any advantage of ABD over USAD in terms of safety. In the present study, the ABD group exhibited a lower rate of POPF and mortality, more dissected lymph nodes, and a shorter hospital stay than the USAD group in LDG with lymphadectomy for 240 gastric cancer patients. Thus, the present report is the largest series comparing the short-term surgical results of an ABD and a USAD in LDG and the first to demonstrate the safety of an ABD over a USAD in reducing POPF and mortality in LDG.
Several limitations associated with the present study warrant mention. First, this study employed a retrospective, single-center, non-randomized design. We compared the short-term outcomes of ABD and USAD after matching two groups using propensity scores to reduce any bias in the comparison. However, there may have been unknown confounders, including the potential for selection biases, so the overall results should be interpreted cautiously. Second, the superiority of an ABD with regard to oncological outcomes is not yet conclusive, as long-term surveillance has not been conducted. Third, other factors, such as advances in individual surgical techniques, might have influenced the improvement in surgical outcomes. Because LDG with the ABD was a new procedure for some surgeons at the start of the study, the ABD group included cases in which the surgeon was using the device for the first time. Thus, even in single-center trials, it can be very difficult to ensure that all doctors have the same level of experience and proficiency. However, this study is the largest series comparing the short-term surgical results of an ABD and a USAD for LDG and is the first to demonstrate the safety of an ABD over a USAD in reducing POPF and mortality following LDG.