[Anatomic study and clinical practice of mesopancreas and total mesopancreatic excision].

Objective: To explore the anatomical characteristics of the mesopancreas, to define the range of the total mesopancreas excision and to evaluate the feasibility, safety and effectiveness in the treatment of pancreatic cancer. Methods: A regional anatomical and pathological study was performed on 14 cadavers with large slices and paraffin sections. The clinical and pathological data of 58 consecutive patients underwent total mesopancreas excision for pancreatic head carcinoma from January 2013 to December 2015 were prospectively collected and analysed. The perioperative morbidity, mortality and clinical outcomes of patients underwent total mesopancreas excision were compared with the patients underwent conventional pancreaticoduodenectomy from January 2010 to December 2012. Results: The mesopancreas located in the retropancreatic area, extending from the head, neck, and uncinated process of pancreas to the aorto-caval groove, in which there were loose areolar tissue, adipose tissue, nerve plexus, lymphatic and capillaries. Although no fibrous sheath or fascia like mesocolorectum was found around the structures, a relatively fixed extent could be defined according to its embryologic and anatomic characters. In clinical practice, total mesopancreas excision was classified into two levels according to the extent of resection in this series: level Ⅰ was a"standard total mesopancreas excision" or"total mesopancreas excision in a narrow sense" , which was similar to the extent of standard resection from consensus statement of ISGPS. Level Ⅱ was defined as any procedure extending the range of level Ⅰ, called the"extended total mesopancreas excision" or"total mesopancreas excision in a broad sense". In TMpE group, the intraoperative blood loss( (461.4±184.5)ml vs. (532.2±319.8)ml, P=0.301), operation time( (368.6±92.5)minutes vs. (397.1±112.7)minutes, P=0.559), total complication rate (39.7% vs. 51.2%, P=0.250), fistula mortality (25.9% vs. 30.2%, P=0.628) were all reduced. There were significantly higher R0 rate (91.4% vs.76.7%, P=0.041) and more harvested lymph nodes (16.2 vs. 11.4, P=0.000) and lower total and local recurrence: rate (half-year local recurrence rate: 7.8% vs. 23.7%, P=0.036; one-year local recurrence rate: 18.2% vs. 39.5%, P=0.018) and longer disease-free survival (16.9 months vs. 13.4 months, P=0.044) and overall survival(22.5 months vs. 19.9 months, P>0.05) were also found in the study group. Conclusions: Mesopancreas is different from mesorectum since it has no fascial envelop, which should be regarded as a surgical concept, rather than an anatomical structure. Total mesopancreas excision is safe and feasible for pancreatic head cancer and probably helps to increase the R0 resection rate and improve the clinical outcomes.目的： 探讨胰腺系膜的解剖学结构并验证其临床应用的可行性、安全性及有效性。 方法： 局部解剖14具尸体胰腺及其周围组织，整块获取标本，蜡块包埋并制作大切片，行相应解剖学、组织学及病理学研究。前瞻性收集2个中心自2013年1月至2015年12月以全系膜切除术式连续进行的58例胰头癌行胰十二指肠切除患者的临床资料，并与2010年1月至2012年12月行传统术式的43例患者比较研究，评价两组患者的临床及病理特点。 结果： 胰腺系膜区域以腹腔干及肠系膜上动脉起始部为核心，从胰腺头颈部及钩突延伸至主动脉-腔静脉平面，富含神经、血管、淋巴脂肪组织，该区域无纤维组织鞘包裹。狭义的胰腺系膜范围：上界为肝总动脉，下界为十二指肠下缘，前界为门静脉及肠系膜上静脉后壁，后界为胰十二指肠背侧融合筋膜，外侧界为十二指肠外缘，内侧界为腹腔动脉干与肠系膜上动脉中点连线，其相应范围的手术定义为"标准的全系膜切除" ；由临床角度任何超过狭义系膜范围者定义为广义或"扩大的全系膜切除" 。全系膜切除手术组(TMpE组)术中出血量[(461.4±184.5)ml]、手术时间[(368.6±92.5)min]、围手术期总并发症发生率(39.7%)和胰瘘发生率(25.9%)较对照组[(532.2±319.8)ml、(397.1±112.7)min、51.2%和30.2%]均有降低(P值均<0.05)，R0切除率显著提高(91.4%比76.7%，P＝0.041)，淋巴结清扫数目增加[(16.2±2.8)枚比(11.4±2.5)枚，P＝0.000]，半年局部复发率(7.8%比23.7%)和1年局部复发率(18.2%比39.5%)均降低(P值均<0.05)，无病生存期延长(16.9个月比13.4个月，P＝0.044)。TMpE组患者总生存期长于对照组(22.5个月比19.9个月)，但差异无统计学意义(P>0.05)。 结论： 胰腺系膜不同于结直肠系膜，没有明确的纤维组织鞘包绕及解剖学边界。作为临床理念而非解剖学结构，TMpE有助于规范手术切除范围，提高R0切除率，改善患者预后。.