Introduction

Nowadays, laparoscopic colorectal resection is gaining widespread popularity because it is associated with less blood loss, quicker recovery, and shorter hospitalization than open surgery as well as equivalent oncological benefits. In laparoscopic surgery, bowel transection and reconstruction are very important for  oncological efficacy and surgical safety, especially avoidance of anastomotic leakage (AL). Although multiple factors such as total mesorectal excision (TME) surgery, low anastomosis, preoperative chemoradiation, advanced tumor stage, and multiple firings of the linear stapler are proven to increase the risk of postoperative AL, the technical aspect of colorectal transection and anastomosis is the dominant contributing factor [1].

Since the introduction of the double-stapled technique (DST) anastomosis described by Knight and Griffen, sphincter preservation is more feasible, and is, therefore, frequently used in laparoscopic rectal cancer surgery [2]. However, the DST procedure creates at least two staple lines which cross each other, resulting in bilateral stapled corners (so-called “dog ears”).

“Dog ears” are a crucial drawback of DST in colorectal anastomosis. These structural weak spots are reported to significantly increase the incidence of postoperative AL. Moreover, from the oncologic viewpoint, the “dog ears” remaining at bowel stump are potential ischemic areas where local recurrence might occur. To eliminate the impact of “dog ears” on postoperative AL, surgeons have made efforts to establish or modify reconstructing techniques for both open and laparoscopic surgery. However, in laparoscopic surgery, existing techniques involve one or more firings of the linear stapler, which has also been reported to be associated with potential postoperative AL [1].

We introduced the vessel sealing system (LigaSure) instead of linear cutter to transect bowel. Our preliminary results show that this novel technique, avoiding the formation of “dog ears”, is feasible, safe, and hence likely to decrease the risk of postoperative AL.

Materials and methods

Between September 2017 and February 2018, 22 consecutive patients with rectosigmoid or sigmoid colon cancer treated at West China Hospital, Sichuan University, were identified retrospectively. Informed consent was obtained from all patients prior to surgery. Ethical approval was obtained from the ethics committee.

Operative technique

The mesorectum or mesocolon was divided at a point greater than 5 cm distal to the lower edge of tumor. The vessel sealing system (LigaSure, Covidien) was then applied to the bowel for transection. Before pushing the LigaSure knife forward for cutting, LigaSure was fired two–three times to ensure better fusion of bowel walls (Fig. 1). To verify the success of LigaSure transection, we introduced the term “burst degree” after bowel transection. Burst degree of the sealed bowel endings was recorded as “no burst”, “minor burst (≤ 1/4 of the sealed line)”, and “major burst (> 1/4 of the sealed line)”. And major burst was considered failure of LigaSure bowel transection. In addition, any outflow of luminal contents from transected bowel stumps was also recorded. Usually, two–three cuttings were needed to transect the bowel. In case of burst of the proximal ending, Hem-o-Loks were applied to close it temporarily. A running suture was placed on the distal stump of the rectum intracorporeally without knotting (Fig. 2). Through a small incision made in the midline, the proximal colon was exteriorized for resection. The stapler anvil was placed in the proximal colon. Via the anus, the circular stapler device was introduced into the distal bowel, and the central rod with the plastic cap was carefully brought out through the central point of the sealed bowel. After this, the prolene suture was knotted tightly (Fig. 3). A true end to end anastomosis was fashioned without dog ear formation (Fig. 4). Additional reinforced running suture of anterior anastomotic line was selectively performed. The bowel transection and construction time was recorded from the initiation of transection using LigaSure to the end of formation of the anastomosis. Finally, proximal 5 ml of intraperitoneal washing fluid was collected for bacterial culture to detect any potential outflow of luminal contents after transection.

Fig. 1
figure 1

Transection of bowel: in a tension-free manner the vessel sealing system (LigaSure) vertically clamped the “naked” bowel and transected it

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Fig. 2
figure 2

Closure of distal rectal stump: suture the distal rectal stump with prolene to close the bowel, but do not knot

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Fig. 3
figure 3

Fix the stapler device: knot the sutured prolene around the stapler device

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Fig. 4
figure 4

True end to end anastomosis without “dog ear” formation

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A demonstration of this procedure is presented in the supplementary video.

Results

Twenty-two patients (12 men and 10 women) with colorectal cancer (11 with rectosigmoid cancer, 11 with sigmoid cancer) were included in this study. Although two patients suffered minor bursts of the sealed bowel endings, none had outflow of luminal contents. Bacterial culture indicated three cases of bacterial growth [E. coli (n = 2) and citrobacter (n = 1)] in the intraperitoneal washing fluid. The hospitalization expenses were estimated to be US$613 cheaper than those with linear cut stapler for bowel transection.

The median operative time was 137.5 (range 108–250) min including one patient with simultaneous sigmoidectomy and hepatectomy (250 min). The mean bowel transection and reconstruction time was 30.0 (standard deviation 3.2) min. The median estimated intraoperative blood loss was 30.0 (range 10.0–60.0) ml. One patient suffered intraoperative anastomotic bleeding which quickly stopped after suturing.

There were no short term complications. Patients’ median times to first flatus and liquid diet intake were both 3 days. The median postoperative hospital stay was 6 days. Two patients suffered from postoperative complications, one had urinary retention, and the other had bowel bleeding, which was successfully managed conservatively. No postoperative AL or surgical site infections were observed (Table 1).

Table 1 Intraoperative and postoperative outcomes
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Discussion

In our preliminary experience, surgical outcomes including operative time, bowel transection and anastomosis time, estimated blood loss, and postoperative hospitalization were favorable, demonstrating that the modified colorectal anastomosis technique using LigaSure for laparoscopic bowel transection is feasible and safe in rectosigmoid or sigmoid cancer.

Chen et al. evaluated a modified laparoscopic DST technique by suturing two “dog ears” around stapler trocar, a technique based on a previously described open procedure [3]. Kang’s team described a modified DST technique through suturing the staple line to cut off “dog ears” either by exteriorizing the distal stump or through a Pfannenstiel incision [4]. Unlike DST, hemi-DST and single-stapled double purse-string anastomosis (SST), both aiming at eliminating “dog ear” formation, were respectively described in a sigmoid colon cancer and rectal cancer population. However, these modifications extend the operative time or needed expensive stapler/stapler firings. In this study, we introduced a novel technique to eliminate the formation of “dog ears” in the anastomosis process and totally leave out of DST or SST. As a result, we observed no AL events in the perioperative follow-up, and the median operation time was as short as 137.5 min.

To the best of our knowledge, our technique is the first to use the vessel sealing system LigaSure for large bowel transection and reconstruction. Since its introduction, LigaSure has been successfully used to achieve haemostasis in blood vessels with a diameter of up to 7 mm. This device applies mechanical pressure and energy to vessels or tissues, resulting in denaturation of collagen and elastin. Due to its advantages in coagulation and sealing, LigaSure has been explored to for bowel transection and intestinal anastomosis in in vivo models, appearing to be sufficient for AL prevention. Manson also reported that LigaSure could increase the length of mesenteric stretch, compared to stapling, in a pig model [5]. When our technique is used to resect and close large bowel laparoscopically, no outflow of luminal contents was observed and none of the three cases suspected of bacterial contamination developed any complications.

Our procedure with LigaSure sealing system reduced operative costs and operation time. This led to an estimated $613 saving in operation costs compared with the cost of using staplers. The results were in line with those reported in two other publications. Manson et al. reported that their clinical bariatric practice using bipolar sealing for mesenteric division saved an estimated $346.79 in hospital costs [5]. And another team reported $129 savings using LigaSure for vascular control compared to the Endo-GIA stapler [6].

Conclusions

This novel laparoscopic anastomosis with LigaSure, eliminating “dog ear” formation, is a technically feasible, safe, and economical procedure for treating rectosigmoid or sigmoid cancer. A large prospective controlled study is warranted to determine the long-term outcomes associated with this procedure.