| BackgroundLiver resection(LR)remains the preferred treatment modality for space-occupying hepatic lesions.With the constant development and innovation of medical technology,the safety and efficiency of laparoscopic minimally invasive surgery have been overwhelmingly improved.For the advantages of less injury,better cosmetic results and rapid recovery,it has been adopted and learned by most surgeons.However,laparoscopic hepatectomy(LH)also has its limitations.Due to the complexity of liver anatomy,intraoperative blood loss remians the main obstacle which limits the application of LH.Laparoscopical hepatic parenchymal transection carries a fatal risk of bleeding,especially for cirrhosis liver.Therefore,how to control the bleeding in hepatic parenchymal transection is the main focus of the present study.Previous study has demonstrated that radiofrequency ablation(RFA)(HabibTM 4X)assisted hepatic parenchymal transection achieved great clinical results.Besides,we found that 915 MHz microwave antenna(MA)assisted LH was safe and efficient in decreasing intraoperative blood loss.However,the RF and MA devices are all straight lined designs and are limited by the "two-point-one-line" effect on the abdominal wall and liver surface.They are available only for peripherally located lesions and are performed in a confirmed direction.In order to complete the operation,more liver parenchyma will be sacrificed.Therefore,the exploration and development of high-performance device in assisting hepatic parenchyma transection is of great clinical significance,and it will promote the development of hepatic surgery effectively.ObjectivesThe objective of the present study is to explore a free,flexible and arbitrary rotation microwave antenna for LH.Firstly,by simulating 600C temperature distribution of F915MMA through multi-point temperature-measuring in liver phantom,we aimed to provide a theoretical basis for surgeons to select the appropriate combination of parameters,and determine the feasibility of using flexible microwave antenna in LH preliminarily.Secondly,we verified the accuracy of 600C temperature distribution of F915MMA in liver phantom utilizing porcine liver in vitro.In this experiment link,we explored the profile of porcine liver under different combination of power and duration,and screened out the appropriate parameter for liver pre-coagulation.Then,we verified the safety and feasibility of F915MMA-assisted LH in porcine liver in vivo preliminarily.Finally,the data of 48 patients who underwent LH from September 2016 to December 2018 were analyzed;12 patients underwent F915MMA-assisted LH.They were regarded as flexible group,and the others were considered as control group.We further evaluated the safety and feasibility of F915MMA in LH through comparing the volume of intraoperative blood loss,duration of hepatic portal occlusion,postoperative liver function and the incidence of postoperative complications.In the same period,the data of 3 patients underwent F915MMA-assisted LPS was collected.We evaluated the safety and feasibility of F915MMA in LPS preliminarily.Methods1.Unremitting efforts and repeated attempts were made to design a laparoscopic 915MHz microwave antenna which was flexible and high temperature resistance by consulting the database and cooperating with the manufacturer.2.Thermocouple was applied for precise temperature-measuring in liver phantom.Finite element method was used to simulate the 60 Ctemperature distribution of F915MMA under different power(30W,40W,50W,60W,70W,80W)and duration(50S,100S,150S,200S).3.According to the results of F915MMA in liver phantom,the profile of F915MMA under different powers(40W,50W,60W)and durations(50S,100S,150S,200S)were further validated in porcine liver in vitro.Then we selected the most appropriate combination of power and duration.4.Ten porcine LHs were divided into two groups randomly.Five of them were treated as Flexible group and the others as Control group.Left lateral lobectomy by laparoscope was performed.In the Flexible group,F915MMA was used firstly,and the rest operation was the same as the Control group.5.Forty-eight patients who underwent LH in the department of hepatobiliary and pancreatic surgery of the first affiliated hospital from September 2016 to December 2018 were included in the study.Twelve patients underwent F915MMA-assisted LH.They were regarded as Flexible group,and the others were considered as Control group.The amount of intraoperative blood loss,duration of the first hepatic hilar occlusion,the incidence of complications and the liver function after operation were compared between the two groups.6.Data of 3 patients underwent LPS were collected between September 2016 and December 2018.We analysed the duration of operation time,intraoperative blood loss,conversion to laparotomy,blood transfusion and the postoperation complications.Results1.The F915MMA invented independently by our team possessed the characteristics of free bending and flexible rotation.The compact and dexterous appearance allowed it to reach any locations of the narrow abdominal cavity.It has the function of precise puncture as wll as pre-coagulation.The multi-angle bendable gripper can rotate 360-degree along the long axis and tilt 45-60-degrees perpendicular to the short axis as well.2.In liver phantom,the temperature rised fastly at the initial stage.The slope of the temperature rising curve was the largest at the monment,and then reached a plateau shortly.The accurate distribution of thermocouple could effectively simulate the 60?-temperature distribution of F915MMA.According to the three-dimensional temperature distribution,the long and short axis of thermal damage scope of F915MMA at 600C could be estimated.3.The profile of porcine liver in vitro was "elliptical" under different parameters combination.Three regions were seen clearly.The profile of F915MMA in porcine liver in vitro was almost the same as that under the same power and duration combination in liver phantom.There was no significant difference.The pre-coagulation range(4.6±0.35 cm long axis and 1.5±0.22 cm short axis)under 50W/100S meet the envisaged clinical needs.4.A safe and stable F915MMA assisted LH miniature porcine model was established.F915MMA could rotate freely and flexibly in LH in vivo with great application experience.The mean operation duration in flexible group was 53.3±12.5 minutes,which was significantly shorter than 87.5±17.8 minutes in control group(P<0.05).The mean duration of first hepatic portal occlusion in flexible group was 12.9±6.3 minutes,which was significantly shorter than that in control group(31.5±7.6 minutes).It has statistical significance(P<0.05).The mean duration of hepatic parenchyma transection in flexible group was 17.3±7.8 minutes,which was significantly shorter than that in control group(37.9±6.4 minutes)(P<0.05).The mean intraoperative bleeding volume in flexible group was 39.5±15.4 ml,which was significantly less than 153.0±60.6 ml in control group(P<0.05).5.Forty-eight patients who met the inclusion criterias were divided into a flexible group and a control group.There was no significant difference in the preoperative data,including age,gender,BMI,classification of cirrhosis and liver function between the two groups.The mean intraoperative blood loss in flexible group(154.17±68.95 ml)was significantly lower than that in control group(284.86±294.68 ml),which had statistical significance(P<0.05).The mean frequency of first hepatic portal occlusion in flexible group(1.50±0.52 times)was significantly less than that in the control group(2.35±1.14 times),which had statistical significance(P<0.05).The mean duration of first hepatic portal occlusion in flexible group(22.50±7.83 min)was significantly shorter than that in control group(35.95±17.2 min)(P<0.05).The incidence of complications in flexible group(33.3%)was significantly lower than that in control group(80.5%),which had statistical significance(P<0.05)6.In F915MMA-assisted LPS,there was no conversion to laparotomy,no blood transfusion,as well as postoperative complications.The operation duration was about 100-150 minutes,the median operation time was 120 minutes,the intraoperative blood loss was 40-60 ml,and the median bleeding volume was 50 ml.Conclusion1.The F915MMA can bend freely and rotate flexibly,which is an innovative device.The combination of F915MMA and the matching multi-angle gripper has great potential in laparoscopic liver surgery.2.The MA itself influence the temperature gradient most in the near field of microwave.The heat conduction of phantom is the main influence in the far field of microwave.The 60?-temperature field distribution of F915MMA can be simulated effectively in liver phantom.The profile of long axis and short axis can be estimated.3.The feasibility and accuracy of 600C-temperature distribution of F915MMA in liver phantom are verified by F915MMA in porcine liver in vitro.50W/100S is regarded as the ideal combination which could meet the clinical needs and will be used for further research.4.A safe and stable F915MMA assisted LH miniature porcine model is established.F915MMA can rotate freely and flexibly in LH in vivo with great application experience.The flexible group has less intraoperative blood loss,less first hepatic portal occlusion durations,less hepatic parenchymal transection durations and shorter operation durations than the control group.It indicates that F915MMA is safe and feasible in LH in porcine liver in vivo.5.Compared with control group,the flexible group has less frequency of first hepatic portal occlusion,shorter duration of first hepatic portal occlusion,less intraoperative blood loss and fewer incidence of postoperative complications.The F915MMA is safe and feasible in LH,and it is promising in LPS. |
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