In this study, the anus was pushed forward from the perineum to make the surgical plane closer to the pelvic entrance to obtain wider surgical space, which reduced the use of stapler cartilages, saved economic costs, and reduced the incidence of anastomotic leakage. Due to the soft tissue structure of the pelvic floor and the course of the rectum itself, the distal rectum can move forward by pushing the anus of the patient who is in the Lloyd-Davies position. Although the distal rectum is moved forward only 2.51cm on average with this method, the increased operating space for funnel-shaped pelvis and laparoscopic surgery with refinement and magnification is huge.
Anal preservation of low rectal cancer is still very difficult for men with narrow pelvis and obese patients. With the development of laparoscopy and anastomosis technology, as well as the mature of ISR technology in recent years [9], it has become a reality to preserve the anus of rectal cancer patients whose tumor distance from the anal margin is less than 5cm. In addition to the traditional laparotomy, the surgical methods mainly involve the robotic-assisted laparoscopic surgery (R-TME) [10], the laparoscopic total mesorectal excision [11], and the transanal total mesorectal excision (taTME) [12]. It is not yet possible to prove which approach is more advantageous [13]. Some studies recommend taTME for obese male patients and low rectal cancer [14, 15], however, in some countries such as Norway, this procedure was discontinued due to a higher incidence of postoperative anastomotic leakage than nationwide, unfavorable local recurrence rates and growth patterns [16]. Bedsides, inclusion criteria regarding the distance of the tumor from the anal verge have not been standardized and taTME may cause unnecessary organ loss with very low potential morbidity and functional defects of the anastomosis [17]. And the robotic surgery is not widely used due to the high cost and the complexity of the operation, so the laparoscopic mesorectal resection is still the main surgical method [13].
In terms of the anastomotic leakage, how to reduce its rate of low rectal cancer has always been a huge problem. Studies have reported that the incidence of anastomotic leakage after rectal cancer surgery is 3–26% [18–20]. The distance between the tumor and the anal margin is an independent risk factor for anastomotic leakage after laparoscopic sphincter-preserving surgery for rectal cancer [21, 22]. Currently, the stapler cartilages of the linear staplers still cannot be rotated 90° laparoscopically because of its structure. In addition, due to the narrow space in the lower part of the funnel-shaped pelvis, the surgical dissection and the creation of an anastomosis is technically challenging and often require additional stapler cartilages to complete the surgical procedure. Some studies have shown that anastomotic leakage is related to the number of stapler cartilages used. Three or more cartilages of the linear stapler are a risk factor for anastomotic leakage [23–25]. In addition, recent systematic evaluation has shown that using two cartilages also have a higher incidence of anastomotic leakage than using one during laparoscopic rectal cancer resection [26]. In all of our patients with anastomotic leaks, the number of stapler cartilages used was more than two, which may have contributed to a higher incidence of anastomotic leaks in the conventional surgery group. It is reported that the limited vascular supply is an important risk factor of anastomotic leakage [27]. The more stapler cartilages used during the operation, the more the Junction and length of the cutting edge, and the worse blood supply of the anastomosis, can lead to the greater risk of postoperative anastomotic leakage [28].
In this regard, during the rectal transection, we create an innovative method that pushing the anus forward from the perineum to bring the operating plane closer to the pelvic inlet. And a wider operating space can be obtained, so that the resection margin can be nearly perpendicular to the long axis of the rectum with the use of the linear staplers, which helps to reduce the number of stapler cartilages used in transverse rectal transection. In addition, the pushing technique can also reduce the tension during nailing to a certain extent, improve the nailing effect accordingly, and protect the integrity of the seromuscular layer and the blood supply of the broken end of the rectum better. All of these are helpful to reduce the occurrence of anastomotic leakage.
Furthermore, it saves economic costs due to the reduction in the number of stapler cartilages. Therefore, this useful technique has the advantage to popularize easily. However, the weaknesses of the study lie in retrospective nature and small number of the patients. Further studies will involve more patients and studies of short-term and long-term surgical outcome.