Surgery is the main treatment for patients with resectable gastric cancer, and D2 lymphadenectomy is recommended as the standard surgical approach for patients with curable gastric cancer . Hand-assisted laparoscopic surgery which relies on the tactile feedback, dexterity of the hand during surgical procedures and the advantages of clear and broad laparoscopic vision is widely used in various abdominal surgery operations [20,21,22,23]. In addition to that, hand-assisted laparoscopic surgery also has a shorter learning curve  and can achieve similar surgical results as laparoscopy-assisted gastrectomy . Previous studies showed that lymph node dissection is still an inevitable difficulty for laparoscopic radical gastric cancer surgery due to the abundant blood vessels around the stomach, constriction of the visual field and the complexity of anatomy, such as the NO.6 group lymph node [9, 25]. In hand-assisted radical gastric cancer surgery, the degree of surgical operations difficulty was increased when face the problems of obese patients, omentum hypertrophy, gastric antrum tumors with huge volume, and short transverse colonic mesentery with using the “cabbage type lymph node dissection”. Especially, the performance is more difficult when dissecting the lymph nodes groups of 5, 6, 8a and 12a, because vision is blocked by a portion of the transverse colon and the stomach in the first step. The technical difficulties of lymph node dissection may restrict the development of hand-assisted laparoscopic radical gastric cancer surgery. Therefore, to find a more suitable way for hand-assisted laparoscopic radical gastrectomy for lymph node dissection is urgently needed. Over the years, we keep summarizing clinical experience and thinking about solutions during the hand-assisted laparoscopic radical gastric cancer surgery. Ultimately, we improved and named a novel pattern of lymph node dissection-the reverse rolling-mat type lymph node dissection , and was also known as “reverse-sheet-folding-like procedure” , which effectively solves the dilemma faced by the traditional lymph node dissection pattern through the optimization of the surgical procedure. In fact, many surgeons use similar lymph node dissection in complete laparoscopic or even robot-assisted gastric cancer surgery, but we elaborated and named this lymph node dissection mode for the first time.
As reported previously, the technical difficulties were associated with conventional open gastrectomy with D2 lymphadenectomy of gastric cancer in patients with high body mass index (BMI) values, since the N2 regional lymph nodes lie deep within the fatty tissues around the major abdominal vessels, and may be associated with short-term surgical outcomes and hemorrhage [26, 27]. Prior to this, it was often performed lymph node dissection using the traditional “cabbage type” in HALTG. However, it is difficult to complete the first step of the “cabbage-style” operation when facing in the obese patients, obese omental tissue, gastric antrum tumors with huge volume, and short transverse mesocolon . We can't dissect smoothly under direct vision because it is difficult to drag the gastroomentum by the small operating space. Even, we have to change operation mode from laparoscopic to open surgery. On the contrary, the approach of “reverse rolling-mat type lymph node dissection” avoid effectively the difficulties of surgical operation under direct vision of the first step of using "cabbage-type lymph node dissection ". We can remove the lymph node groups of No. 8, No. 5, No. 12a, and No. 6 under direct vision because the excised stomach and omentum had been removed from the abdominal cavity before completing hand-assisted laparoscopic lymph node dissection. Of course, the lymph node groups of No. 8, No. 5, No. 12a can also be performed under laparoscopy if convenient for practical operation. Therefore, it can continue to keep the technical advantages of lymph node dissection under direct vision. In addition, it also avoids pulling and squeezing the tumor in the middle and lower stomach; at the same time, we can directly expose the celiac trunk and the common hepatic artery, which is conducive to remove groups of 8a, No. 9 lymph nodes under direct vision and the pylorus areas were more clearly revealed.
High BMI can also cause technical difficulties in laparoscopic-assisted gastric surgery for inexperienced surgeon [28, 29]. However, the difficulty of the surgical procedures is significantly reduced through combine improved reverse procedure method with the advantages of hand-assisted laparoscopy. According to our clinical experience, this novel pattern of lymph node dissection is more suitable for the patients with a larger body mass index. Therefore, in our statistical results, the average body mass index of patients in the “reverse procedure” group is greater than that of the “cabbage type” group; which may be related to that we tended to choose the “reverse procedure” for patients with heavier weight. In our study, the “reverse procedure” group had longer average surgical procedure time, but the intraoperative blood loss was significantly lower than that of the traditional “cabbage type” group. We believe that the longer operation time may be related to the fact that patients had higher average BMI in the ”reverse procedure” group; even so, the “reverse procedure” group showed it is more satisfactory in reducing intraoperative blood loss. This is the result of our optimization of the operation method, because we can more clearly reveal the anatomy through this surgical procedure. Generally speaking, obesity and the history of upper abdominal surgery will affect the lymph node dissection of D2 radical surgery for gastric cancer . But, the results from our study shows unexpectedly that more lymph nodes harvested lymph nodes in the “reverse procedure” group. On the one hand, the reason is that we have optimized the surgical procedure; on the other hand, postoperative pathological specimen lymph nodes were collected by the surgeons and pathologists jointly in the “reverse procedure” group. While, in the “cabbage type” group, the lymph nodes were collected alone by the pathologist alone. Although all operations are performed by the same group of doctors, and the extent of lymph node dissection is carried out in accordance with the standard D2 radical surgery sweeping range, there is no denying that the examination of pathology specimens is a flaw in this study. Currently, we don't more research on reverse procedure in laparoscopic-assisted gastrectomy, we also believe that this optimized lymph node dissection can still be applied to the HALG well.
In addition, in our study, the follow-up rate of patients in the “cabbage type” group was 91%, and the follow-up rate of the “reverse procedure” group was 88.8% within 3 months. There were studies show that the incidence of postoperative complications in the laparoscopic-assisted total gastrectomy for gastric cancer ranged between 10 and 40% [31, 32], and Our research results are also in this range. There was no significant difference in overall complications between the two groups, these scores were comparable to rates reported in other studies . Unfortunately, 2 cases of duodenal stump leakage occurred in the cabbage type group after surgery, and 1 case of anastomotic leakage occurred in the reverse procedure group. All patients were improved and discharged after treatment. The incidence of “reverse procedure” group was lower than the “cabbage type” group in terms of recurrence and metastasis; but there was no statistical significance (P = 0.093) between the two groups. Nevertheless, we think the difference will be statistically significant, with number of cases increasing. One case of death due to tumor progression occurred in the two groups, respectively, which was not statistically significant. It further verified the safety and efficacy of reverse rolling-mat type lymph node dissection.
Our study has some limitations. First, this was a retrospective single-center study with a relatively small sample size. Second, although the survival rate of “reverse procedure” seem to be no less than that of “cabbage type” group, we lack more convincing evidence of 5-year survival. From the perspective of evaluation of the safety and feasibility of surgery, this will not have much impact on the study. Further large-scale survival analysis will help to verify this result, and it is also the direction that we will study next.
Overall, both the two different pattern of lymph node dissection can reach the standard of D2 lymph node dissection for radical gastric cancer, and there are no significant differences in terms of hospitalization time, incision length, postoperative complications, and long-term prognosis between the two groups. On the premise of retaining the tactile feedback and flexibility of the hands in hand-assisted radical gastric cancer surgery, we have completely solved the difficulties of laparoscopic lymph node dissection by optimizing the method of lymph node dissection. Our results suggest that the novel method in addition to optimizing surgical procedures, it can also reduce intraoperative bleeding obviously. Although the increase in the number of lymph nodes is partly due to the results of the clinicians and pathologists examined corporately, it is undeniable that changes of the surgical procedures played an important role.