BULLDOG,A Useful Vascular Occlusion Tourniquet in Laparoscopic Liver Resection

Since the Louisville Statement in 2009, the use of laparoscopic
liver resection (LLR) had gradually increased in recent years...

postoperative mortality, morbility and recovery of liver function are associated with major blood loss [10] which is always the main cause of conversion to laparotomy [11] and remains a challenge for surgeons [12,13]. Pringle [14]first described the method to arrest the hepatic hemorrhage by compression of the porta hepatis and this procedure was widely spread as well as the in laparoscopic field currently. Here, we described a new modified of Pringle maneuver using Bulldog to block vascular during LLR, and compared its effects with traditional pringle maneuver.

Patient Population
From Dec, 2014 to Jan, 2019,200 patients underwent LLR in our department, at the 2nd hospital of Anhui medical university and in which 110 patients underwent LLR with vascular occlusion.
There were 54 patients in the Bulldog group, and 56 patients in the traditional group.38 femail and 72 mail participants were included in this study, with the mean age of (56.1±10.9 and 60.0±8.8) years old, Respectively. Clinical characteristics of patients, were summarized in Table 1.

Inclusion and Exclusion Criteria
This study has been approved by the ethics committee of The Second Hospital of Anhui Medical University. Each participant in the study provided written informed consent. The inclusion criteria including: a.
All the participants were corresponded with the application of LLR, according to the Louisville Statement [2,8] and underwentlaparoscopic liver resection.
b. The bulldog and cotton tape were applied in operation.
c. The tumor did not invade main vessels.
d. Pringle maneuver clamping time was unified as 15min every time and right Glission pedicles was clamped only once.
The LLR was not limited to the disease, including benign tumor，malignance tumor, calculus disease and others ( Table   1). The cases that did not agree with the inclusion criteria were excluded. Intraoperative laparoscopic ultrasound was used as a requirement.
Liver parenchymal transection was performed using a combination of a harmonic scalpel, ultrasonic dissector (Cavitron), and bipolar forceps. For cases with Pringle maneuver, the cotton and bulldog method were applied. In the bulldog group, we routinely exploredthe abdominal cavity, dissociated the mucosal tissue around the hepatoduodenal ligament, exposed the hepatic portal as well as the right Glissionean pedicles. Bulldog was delivered into the abdominal cavity with the matched forceps through the 12-mm trocar to block hepatoduodenal ligament or the right Glissionean pedicles ( Figure 2) to block the hepatic inflow. While, in the cotton clamping group, we need another 5-mm port trocar, which should be positioned in proper place to ensure the encircle of the hepatoduodenal ligament, A forceps went through the the hepatic pedicle and an 80-cm cotton tape was placed around it. Then, the ends of the cotton tape were pulled out through the 5-mm trocar port, and a tube was pushed inside the abdominal cavity close to the hepatic pedicle, and was fastened by pulling cotton tape through the tube [16] (Figure 3).
The different lengths of Bulldog, the longer was used to pringle manuever, the other were used to the right Glission pedicles, the unique curved design fits better with the baseline than ordinary straight clamp, further ensuring complete vascular occlusion. B.
The matched forceps,non-working status. C.
Working status. Note: A and B: red arrows represent hepatoduodenal ligament, C and D: red arrows represent the anatomized right Glission pedicle. A: The forceps hold the Bulldog into the abdominal cavity and start to infibulate the hepatoduodenal ligament, it is easy to operate. B:the bulldog can securely clap the hepatoduodenal ligament. C and D: Bulldog was clamped the right Glission pedicles. All the black arrows represent bulldog.

Clinicopathologic Characteristics
Baseline clinical characteristics of patients are shown in

Postoperative Clinical Outcomes
The liver function on PODs 1, 3 and 5 as reflected by the postoperative changes of ALT, AST, TBIL and PT were shown in Table 3  PHS: postoperative hospital stay. TBIL :serum total bilirubin. SD : standard deviation. CRP: C-reactive protein.

Discussion
With the innovations of laparoscopic technique and specialized equipment, laparoscopic liver resection became the dominating resection surgery approach [17]. From Dec of 2014, laparoscopic hepatectomy was firstly carried out in our department, extracorporeal [16,18,19] Pringle maneuver has been applied in most laparoscopic liver resections which need to block the hepatic inflow, the cotton tape was frequently applied [20]. Also, there were many novel devices, Shin-ichiro [21] recommended the smooth and effective way of Biliary Scope for Pringle's Maneuver in laparoscopic hepatectomy in 2007. Next year, Akihiro [22] investigated 32 consecutive patients with Endo Retract Maxi for Pringle maneuver during laparoscopic hepatectomy and Dua MM used umbilical tape [23] in 2015. We used to block the hepatic inflow by extracorporeal Pringle maneuver method with cotton tape5 for its validity , softness and safe for vessel protection, but it was always tricky for clamping in a two-dimensional view to encircle the hepatoduodenal ligament, and it delayed operation time for unexperienced surgeon. Bulldog has been widely used in urinary surgery [24,25] for vascular occlusion, In gynecology, Yang [26] Express the bulldog clamp is a well crossover clamp with serrated blades that effectively occlude vessels without slippage or significant crush injury, is the laparoscopic instrument for minimizing blood loss during the surgical procedure. But bulldog in hepatic surgery has rarely been mentioned, this is the first report to formally demonstrate the clinical application in hepatic surgery.
in this study, we compared the cotton and the bulldog for vascular Postoperative levels of CRP rise at 4-12 h, peak at 24-72 h and return to baseline around 2 weeks [28]. In our study, the level of CRP was significantly lower in the bulldog group comparing to the traditional Pringle group, which demonstrated less surgical trauma in the bulldog group. and the postoperative hospital stay was lower. Throughout most of the data, even though most outcomes were calculated with no statistical differences, outcomes from intraoperative or postoperative in bulldog group were better than the cotton tape group.

Advantages and Disadvantages
Cotton with Extracorporeal Pringle maneuver needs another incision [29], and the tourniquet need to vary following the tumor Second, small teeth covered the bulldog surface which can clamp the hepatoduodenal ligament or the right Glissionean pedicles toughly and no one creep down to guarantee the security. Third , took it out without any difficulties when you need to loosen it to avoid the overlong ischemia reperfusion injury, and reused it after disinfection. Fourth, its special material and easy to manipulate may reduce the risk of injury for vascular [30], bile duct and surrounding parenchyma which contributed to the earlier recovery of postoperative liver function. The last but not the least, They have less incidence of postoperative complications of 54 patients.

Conclusion
Bulldog for vascular occlusion is effective and time saving during laparoscopic liver resection with 54 patients than the traditional group, maybe the number is limited and more information are needed to witness its superiority, but we believe bulldog will be effectively performed approach for suitable patients undergoing laparoscopic liver resection with the advantages of simpleness, security and effectiveness.

Acknowledgement
Liang He and Weixiang Li are co-first authors, Xiaoping Geng and Hui Hou are co-corresponding authors. The authors would sincerely thank the reviewers and editors for critically reviewing and editing this manuscript. This manuscript is being submitted as an original article. This manuscript has not been presented on a society or meeting before.

Funding
The study was supported by grants from Anhui Medical University Science Foundation(2015hhjh05).