| BackgroundEsophageal cancer is one of the most common diseases in the department of thoracic surgery.For early stage esophageal cancer,surgery still is the most important treatment measure so far.Chylothorax after oesophagectomy is a rare but potentially dangerous complication.Once happens it can lead to continue loss of chylous fluid which are rich in lymphocyte and chylomicrons,sometime life might even be fatally endangered.Some scholars suggested that the thoracic duct should be routinely ligated to reduce the incidence of post-operative chylothorax.Meanwhile,other scholars raised an objection that prophylactic ligation of the thoracic duct not only couldn't reduce the occurrence of postoperative chylothorax but also had unfavorable impact on overall survival of resectable oesophageal cancer patients.For the low incidence rate and lack of enough clinical data,management of thoracic duct during esophagectomy remains controversial.With the progress of the medical science,video-assited esophagectomy have developed rapidally and gradually become the mainstream surgical treatment for early stage esophageal cancer with advantage of minimal invasion,lower complication rate,rapid recovery and so on.Under the new minimally invasive surgery procedures,whether should prophylactically ligating thoracic duct during esophagectomy is still an important issue in front of us.The point is how do we evaluate the measure.Finally,we decide to assess this problem in two aspects.It is well known that adequate nutrition is the premise of successful rapid recovery for esophageal cancer patients after operation.Most modern medical views advocate the way of early enteral nutrition after esophagectomy,because it has advantage of stimulating the recovery of gastrointestinal motility,more matching the physiology and so on.The gastrointestinal absorption function directly affects the effect of enteral nutrition after operation.Therefore,the early gastrointestinal absorption function is one aspect that we selected to evaluate the ligation of the thoracic duct.Physiologically,because of the presence of lymphaticovenous communication,when blocked thoracic duct lead to lymphatic obstruction,the lymphatic system and the surrounding venous system gradually establish a collateral circulation.But this process requires time,so flatly ligating of thoracic duct will lead to lymphatic stasis and higher lymphatic pressure within a short time and then increse the pressure in gastrointestinal tissue gap,even lead to tissuse edema,which is bound to affect the absorption function.Because the traditional biochemical indices such as blood lipids,lipoprotein and so on can also be doubly regulated by liver decomposition and synthesis.Meanwhile it also be affected by factors of age,nutritional status,metabolic characteristics.The most important is that these biochemical indices can not immediately reflect gastrointestinal absorption function,so selecting a sensitive and specific real-time quantitative evaluation index is the key.Browsing literature we know that D-xylose is a five carbon sugar xylose.The same as glucose and fructose,after oral administration,it is mostly absorbed passively in the jejunum.But not conversed by the liver after absorbtion,most of them are excreted from the urine in prototype.Having the advantages of simple,quick,stable and easy to quantify,D-xylose absorption test is the best choice to evaluate the early gastrointestinal absorption function for patients after esophagectomy.It is first time to be used in evaluating the effect of the thoracic duct ligation on the gastrointestinal absorption function.This also has become an innovative point of our study.In addition,for a patient with malignant tumor,their immune function plays an important role in tumorigenesis,development and prognosis.Among them,Thymus dependent lymphocyte,or name as T lymphocyte,is on the dominant position during the whole progress of tumor cell recognition,killing and immune surveillance.Therefore,the method of monitoring peripheral blood T lymphocyte subsets by mean of flow cytometry has been widely used to evaluate the immune function of tumor patients.Lymphocytes and various types of immune cells in the blood circulation enter the postcapillary venule,then passed through high-walled endothelium into the lymphatic tissue and lymphoid organs,thus enter the lymphatic circulation.Lymph circulation finally pooled into thoracic duct,and then enter superior vena cava,thus into the blood circulation again.Just due to recirculation of lymphocytes,immune cells can communicate with each other,throughout the whole body and reasonably distribute in lymphatic tissues and organs.In lymphoid organs or lymph tissue,a large number of lymphocyte participate in recycling,called lymphocyte recirculating pool,which is about ten times the total number of lymphocytes in the blood.We konw when thoracic duct is ligated lymphocyte can back to heart through the collateral circulation between the thoracic duct and the azygos vein.Today the focus of our research is whether does ligation of thoracic duct duing thoracoscopic esophagectomy have effect on T lymphocyte subsets.Compared with traditional surgery,there are great differences in steps,time and methods.During thoracoscopic esophagectomy,arch of azygos vein was usually ligated and and transected for easer to free esophagus and clean lymphonode.When the thoracic duct and azygos vein are all ligated,whether peripheral blood lymphocytes will decrease is what we are interested in.Finally,we summary the chylothorax incidence of esophageal cancer patients participated in the previous study.The aim is to evalue the effect of thoracic duct ligation by comparing the chylothorax incidence between ligation group and no ligation group.ObjectiveThe purpose of our study is to estimate the effect of thoracic duct ligation on gastrointestinal absorption,immune function and postoperative chylothorax incidence,for your reference.According to the experimental results and literature analysis,we should seek a more scientific way to manage thoracic duct ligation during the esophagectomyMethod(1)Prepararing different concentrations of standard D-xylose concentration solution,and monitoring its absorbance,then analysis whether the two have linear correlation,and calculate the linear regression equation.All recruited patients were admitted in Department of Thoracic Surgery of Tai'an Central Hospital from August 2014 to December 2015.Squamous cell carcinoma were diagnosed with ultrasonic endoscopic biopsy.Only lower segment and T2 stage patients were enrolled in the research and were randomly divided into thoracic duct ligation group and no ligation group.All patients were perfomedleft transthoracic esophagectomy with anastomosis below the aortic arch by the same group surgeons.The thoracic duct was ligated at 2cm above the diaphragm in the experimental group,which was different from the control group.The sampling time was in the morning on the day of operation and the first day after operation.After 8 hours without energy intake,the venous blood was taken for calibrating.One hours after 200ml D-xylose solution was drinked,venous blood was taken again to detect its absorbance.The D-xylosesolution concentration was calculated according to the absorbance of different specimens to evaluate the gastrointestinal absorption function of the patients.Two samples t-test method was used to compare the difference of D-xylose concentration in peripheral blood between the two groups before and after operation.All data are analyzed by SAS8.0 statistical software in compute.(2)All recruited patients were admitted in Department of thoracic surgery of Tai'an Central Hospital from May 2014 to May 2017.Squamous cell carcinoma were diagnosed with ultrasonic endoscopic biopsy.Only T1N0M0 stage patients were enrolled in the research and were randomly divided into thoracic duct ligation group and no ligation group.All patients were perfomed right transthoracic video-assisted esophagectomy by the same group sugern.With laparoscope,stomach was dissociated and pull out from upper little abdominal incision.Stomach tube was made and instrument anastomosis with esophagus at the neck.The arch of azygous vene was transected during all operation.The thoracic duct was dissociated and ligated at 2cm above the diaphragm in the experimental group,which was different from the control group.The age and sex of the patients were recorded and analyzed by t-test and chi-square test.The peripheral blood lymphocyte count and the percentage were determined with the help of fully automatic haemacytometer analyzer.T lymphocyte subsets ratio detection process is as follows:After lysised red blood cells then washed with PBS,the remained peripheral blood mononuclear cells(PBMC)were stained with three color monoclonal antibody CD4-FITC/CD8-PE/CD3-Percp.Flow cytometry was used to monitor the number and percentage of T lymphocyte subsets.Paired t test was used to compare the difference of lymphocyte and T lymphocyte subsets before and after operation.The difference of lymphocyte and T lymphocyte subsets between the two groups was compared by two sample t test.All data are analyzed by SAS8.0 statistical software in compute.(3)In the previous study a total of 122 patients were enrolled,the postoperative chylothorax incidence were observed.The drainage volume and color of pleural effusion were observed carefully after operation.The pleura effusion were monitored and analyzed in time for patient whose drainage volume increase for no obvious reasion or increase after the decrease in 72h after operation.Those who are positive for chyluria can be diagnosed.Repeated examinations maybe requied for the false negatives possible sometimes.The chylothorax incidence rate were compared between ligation group and no ligation group with quadruple tabular form test.If the theoretical number is less than 1,the exact probability method of the four lattice table is adopted.At the same time,the stratified cohort method was used to calculate the chi square values and the corresponding P and OR values for all the patients involved in the study.All data are analyzed by SAS8.0 statistical software in compute.(4)At last,we had a general review of the present situation for chylothorax prevention and cure after esophagectomy by means of thoracic duct ligation.Search Chinese and English related documents through a variety of search engines and professional medical knowledge base.Summarize related data for comparative analysis.Result(1)Linear-regression analysis was used to calculate regression equation between concentration of D-xylose solution and corresponding absorbance.The relationship between concentration and absorbance was linear,with the lower-limit of quantitation for D-xylose solutive concentration was 0.025 mg/ml and the upper limit of quantitation was 0.2 mg/ml.The linearregression equation was Y=2.3795X+0.0469,in which Y was absorbance and X was the concentration of D-xylose(mg/ml).R2 =0.9982.A total of 62 male patients matched condition.At last 60 patients had been remained after two patients were excluded,one for postoperative chylothorax,another for T3 stage.The peripheral blood D-xylose concentration in ligation group was 143.06±2.92 mg/L before operation,and 139.98±3.42 mg/L after operation.The result in no ligation group was 144.14±3.29 mg/L before operation,and 142.23±2.76 mg/L after operation.The concentration of D-xylose solution was less than that before operation(P<0.05)in the ligation group or the non ligation group.There was no significant difference between the two groups before operation(p=0.1849),and there was a significant difference betweenthe two groups afteroperation(p=0.0066).(2)Four patients were excluded,separately for failed in recognizing thoracic duct,blood transfusion during operation,postoperative chylothorax,T2 stage.At last a total of 60 patients were enrolled in the research and were randomly divided into thoracic duct ligation group(n=28)and no ligation group(n=32).The ligation group 28 patients,23 males and 5 females,the age was 59.89 ±8.34 years old;non ligation group 32 patients,29 males and 3 females,the age was 61.72±5.59 years old.There was no significant difference between the two groups in gender and age(P>0.05).There were no significant difference between the two groups in lymphocyte count,percentage of lymphocytes in WBC,percentage of CD3+lymphocyte in total lymphocyte,percentage of CD3+CD4+lymphocyte in total lymphocyte,percentage of CD3+CD8+lymphocyte in total lymphocyte before operation.After operation,there was no significant difference between the ligation group(0.91 ±0.28)×109/L and no ligation group(0.93±0.34)×109/L in lymphocyte count(P=0.8).There was no significant difference between the ligation group(7.14±1.78%)and no ligation group(8.36±3.26%)in percentage of lymphocyte in WBC(P=0.07).There was significant difference between the ligation group(55.71±7.59%)and no ligation group(59.41±7.01%)in percentage of CD3+lymphocyte in total lymphocyte(P<0.05).There was significant difference between the ligation group(26.75±4.03%)and no ligation group(36.5±6.56%)in percentage of CD3+CD4+lymphocyte in total lymphocyte(P<0.05).There was significant difference between the ligation group(26.57±5.97%)and no ligation group(20.91±7.51%)in percentage of CD3+CD8+lymphocyte in total lymphocyte(P<0.05).Except CD3+CD8+lymphocyte,all test items were significantly lower than that of preoperative for both the ligation group and the no ligation group(P<0.05).(3)A total of 122 patients were enrolled in this study.A total of 61 cases were in the conventional thoracotomy group:ligation group were 31 patients including 1 cases of chylothorax,no ligation group were 30 cases without chylothorax.Because the theoretical number is less than 1,Fisher exact probability method was used to calculate the chi square value.The result show that P=1.It mean that there was no significant difference between thoracic duct ligation group and no ligation group in chylothorax incidence under conventional thoracotomy.A total of 61 cases were in the VATS group:ligation group were 28 patients without chylothorax,no ligation group were 33 cases including 1 cases of chylothorax.The results show that P=1.It mean that there was no significant difference between thoracic duct ligation group and no ligation group in incidence of chylothorax under VATS esophagectomy.Finally,all patients were included in the calculation and analyzed with stratified cohort study.The P=0.963,OR=1.0714.The result mean that no matter under conventional thoracotomy or VATS esophagectomy there was no significant difference between thoracic duct ligation group and no ligation group in chylothorax incidence.(4)A total of 113 literatures were reviewed,the contents of overview include physiological and anatomical characteristics of thoracic duct,incidence and common cause of chylothorax after esophagectomy,diagnosis and treatment of chylothorax after esophagectomy,method and effect of thoracic duct ligation,effect of thoracic duct ligation during esophagectomy on liver function,immune function and long term survival rate and so on.ConclusionLigation of the thoracic duct during operation can reduce the early gastrointestinal absorption function for esophageal cancer patients,at the same time it will lead to decrease of early immune function especially for those with their arch of azygos vein transected.Compareing the postoperative chylothorax incidence between two group,routine prophylactic ligation of thoracic duct can not significantly provent postoperative chylothorax.Combined with the literature,we recommend thoracic duct should not be prophylactically ligated in lower esophageal cancer in earlier stages especially when there is no obvious signs of tumor invasion and thoracic duct injury.On the contrary,for the middle and upper segment esophageal carcinoma,especiallytumor is serious invasion and mediastinal lymph node enlargement need widely sweeping,especially when thoracic duct is highly suspicious of the injured patients,the selective prophylactic thoracic duct ligation are recommend. |
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