Complete Mesoesophageal Excision:A Novel Surgery Approach In Esophageal Cancer Treatment

Objective:The“mesentery”which fixes the guts to the wall of body,contains blood and lymphatic vessels nurturing the guts.“Mesentery”excision with central vascular ligation produces an oncologically superior specimen which include all the tumor tissues and regional lymph nodes.For their perfectly meeting the ideas of“En Bloc”and“complications reducing”,total mesorectal excision(TME)and complete mesocolic excision(CME)have become the standard approaches of rectal and colic cancer.Embryological studies have proved that,in the early stage of embryo,esophagus contains a mesentery-like structure that connects to the aorta.Current studies have reported the existence of mesoesophagus along with descending aorta in the adult.And one step further,tentative descriptions of anatomy of that part of mesoesophagus have arised.But a much more comprehensive and systemic acknowledge of the mesoesophagus of thoracic esophagus needs acquiring.,following with the resolution of large numbers of questions like“What does the mesoesophagus histologically constitute?”?“The mesoesophageal excision should be a'total'type(like TME)or a‘complete'one(like CME)?”“What about the blood losing?lymph node dissection and complications of the mesoesophageal excision?”Therefore,our main aims of this study focus on the anatomy of mesoesophagus of thoracic esophagus under VATS?the feasibility and necessity of VATS complete mesoesophageal excision,as well as the method of it.Method:We retrospectively analyze 57 patients who underwent VATS and laparoscopic esophageal radical excision during April 2015 and December 2016 of single surgery team.After randomly allotting,we find that the CME group includes 25 patients,with 12 Ivor Lewis approach and 13 McKeown approach.And the Non-CME group includes 32patients,with 25 Ivor Lewis and 7 McKeown approach.All the patients underwent VATS and Laparoscopic esophagectomy and systemic lymph nodes dissection,and they all chose stomach conduit for esophageal reconstruction.To patients of the CME group,firstly we open the pleura longitudinally at the spine side of esophagus.Then we find loose connective tissue underneath which lies a fiscia-like tissue.This fiscia-like tissue contains esophageal arteries,thoracic duct and para-esophageal lymph nodes.In later steps,we can see subcardinal lymph node as well lies in this fiscia.This fiscia runs backwards to descending aorta and wraps it.And this fiscia is part of the mesoesophagus.At the pericardial side of esophagus,when pleura is opened,there lies a cavity full of loose connective tissue which is void ofblood vessels.Pericardium and mesoesophagus constitutes the lateral and basal walls of this special cavity.We can see that,in the descending aorta part of esophagus,mesoesophagus wraps esophagus in a“?”way and runs backwards to descending aorta.In it lies esophageal arteries,para-esophageal lymph nodes and subcardinal lymph node.So,dissect the mesoesophagus along with the edge of aorta(we call it the root of mesoesophagus),we can remove the esophagus,tumor and lymph nodes of this part at the same time.Above the level of descending aorta,mesoesophagus divides into two parts-the right mediastinum part and left mediastinum part.In the spinal side,go on to cut open the pleura till the apex.In the trachial side,cut open the pleura along with right vagus nerve and right subclavical artery,underneath which we can see treachio-esophageal arteries,right laryngeal recurrent nerve and para-right LRN lymph nodes.After piercing the mesoesophagus to isolate the right LRN,we can dissect the right mediastinum part of mesoesophagus with lymph nodes.Open the trachea esophagus groove,then suspend esophagus to make the left mediastinum part of mesoesophagus tense to proper extent.Finally,dissect the left part of mesoesophagus along the edge of left LRN.At this time,we accomplish esophagus excision synchronously with lymph nodes dissection through a mesoesophageal excision way.To patients of the non-CME group,we achieve it in a traditional way:we free the esophagus along with its margin,or don't dissect the mesoesophagus at the root of it,then searching for lymph nodes to dissect.Between the two groups,we compare the blood loss,total number of lymph nodes dissected,total number of thoracic lymph nodes dissected,thoracic drainage in the first 3 days,and main complications like anastomal fistula,chylothorax,arrhythmia and some other items correlating to operation.After operation,the mesoesophagus was cut perpendicular to the esophagus wall at 1cmintervals.Each block was finnally subjected to conventional HE staining to detect tumor cells.Result:We observed mesoesophagus in thoracic esophagus.in the descending aorta part of esophagus,mesoesophagus wraps esophagus in a“?”way and runs backwards to descending aorta.In it lies esophageal arteries,para-esophageal lymph nodes and subcardinal lymph node.Above the level of descending aorta,mesoesophagus divides into two parts-the right mediastinum part and left mediastinum part.All the operations were successfully completed with R0 resection.Compared with non-CME group,the CME group achieved less blood loss(242.8±180.3ml VS.354.7±237.4 ml,p=0.048),more total number of lymph nodes dissected(20.2±8.4 VS.15.2±5.9,p=0.016),significantly more total number of thoracic lymph nodes dissected(15.9±6.9 VS.11.2±4.7,p=0.006).The first-3-days-thoracic drainages are not statistically different(1008.0±369.7mlVS.1118.3±468.4ml,p=0.325).No patient died during perioperation and were all discharged successfully.When lipidolo hysecrosalpingography was taken at 7~thh day after operation,one patient from CME group was found with anastomal fistula,and anastomal fistula incidence of CME group is 4%(1/25).No one from non-CME group was found with fistula.And the incidences of fistula of two groups are not statistically different(p=0.689).The chylothorax incidences of CME and non-CME group are 4%(1/25),3.1%(1/32)respectively,and difference is not statistical(p=0.689).Other items like operation time,time of initial ventilator,days of initial ICU,days of thoracic drainage,recurrentnerve palsy and postoperative arrhythmia are not statistically different.And time of Ivor Lewis approach is not statistically different as well(415.8±60.0min VS.405.2±64.6min,p=0.627).Conclusion:In the thoracic part of esophagus,there exists the mesoesophagus.In the descending aorta part of esophagus,mesoesophagus is a double-layer fiscia like mesorectum and mesocolon,wraps esophagus in a“?”way and runs backwards to descending aorta.In it lies esophageal arteries,para-esophageal lymph nodes and subcardinal lymph node.But above the level of descending aorta,mesoesophagus divides into two parts-the right mediastinum part and left mediastinum part,and is a single layer fiscia which contains esophagus,trachea,laryngeal recurrent nerve,trachio-esophagus vessels and lymph nodes.VATS complete mesoesophageal excision is feasible and safe.It produces more thoracic lymph nodes dissection,less blood loss.It can make tumor en bloc synchronously with lymph nodes.But further studies and follow-up are needed to make it clear whether it is efficacious for patients'overall survival.