图6. 一例55岁女性左侧十二指肠旁疝，间断发作的剑突下疼痛3个月，逐渐加重。（a）上腹部增强CT扫描显示近段空肠（J）形成的囊状包块。这个病例没有显示肠系膜下静脉。（b）以上层面往下30mm,CT显示在没有受压变形的胰腺（P）与胃（S）之间，马蹄形坍塌的空肠肠管（三角形箭头）和扩张的肠系膜血管（长箭头）。CT检查后7小时进行了剖腹手术，发现疝囊内存活的空肠肠襻。
Right PDH involves the fossa of Waldeyer, which is located immediately behind the superior mesenteric artery and inferior to the transverse segment of the duodenum with or without rotation anomaly. Right PDH occurs most frequently in cases of a nonrotated small intestine and a normally or incompletely rotated colon. According to the extent of malrotation, right PDH is associated with location of the superior mesenteric vein to the left of, and ventral to, the superior mesenteric artery and with absence of the normal horizontal duodenum. Because the fossa of Waldeyer extends to the right and downward, directly in front of the posterior parietal peritoneum, right PDH develops into the ascending mesocolon with a right colic vein anteriorly. The superior mesenteric artery and right colic vein are located at the anterior-medial border of the encapsulated small bowel loops and are a landmark for right PDH (Fig 7) (30).
右侧十二指肠旁疝多涉及Waldeyer隐窝，该隐窝位于肠系膜上动脉后方，十二指肠水平部的下方，伴或不伴十二指肠旋转异常。右侧十二指肠旁疝患者小肠多未转位，结肠多正常或不完全转位。根据旋转不良的程度不同，肠系膜上静脉位于肠系膜上动脉的左侧和前侧，以及没有正常十二指肠水平部。因为Waldeyer隐窝向右下方延伸，恰好在后腹膜前方，右侧十二指肠旁疝穿过升结肠系膜达其后方，其前方是右侧结肠静脉。肠系膜上动脉和右结肠静脉是疝囊内小肠肠襻的前中边界，是右侧十二指肠旁疝的界标。
Figure 7. Right PDH in a 31-year-old man with sudden onset of severe diffuse abdominal pain. (a) Contrast-enhanced CT scan of the upper abdomen shows a saclike mass of fluid-filled bowel loops (S), most of which were jejunal and proximal ileal loops. (b) CT scan obtained 30 mm below a shows the encapsulated bowel loops herniated through the fossa of Waldeyer (W), which is located behind the superior mesenteric artery (arrowhead) just below the transverse portion of the duodenum (D). I = ileal loops. (c) CT scan of the lower abdomen shows the superior mesenteric artery (arrowhead), which is displaced anteriorly by the entrapped bowel loops. Dilated and converging vessels (arrows) are seen in the mesentery; dilated ileal loops (I) are seen in the left midabdomen. (d) Diagram (coronal view) of the surgical findings shows that the fossa of Waldeyer (light gray area) is 10 cm in diameter. At laparotomy performed 2 hours after CT, 350 cm of strangulated small intestine, located 70 cm from the ligament of Treitz, was found. Because the withdrawn bowel loops were purple, jejunostomy was performed without resection.
图7. 一例31岁男性右侧十二指肠旁疝，突然发作的腹部弥漫性疼痛史。（a）上腹部增强CT扫描显示囊性包块，内见充满液体的肠襻（S），主要是空肠和近段回肠肠襻。（b） 30mm下方CT扫描显示肠襻穿过Waldeyer 隐窝 （W）形成疝囊。疝囊位于肠系膜上动脉（箭头）的后方，十二指肠水平部的下方（D）。I =回肠肠襻。（c）下腹部CT扫描显示疝囊内的肠襻推移肠系膜上动脉（三角形箭头），使其前移。肠系膜内见扩张和群聚的血管（箭头）。左中腹见扩张的回肠襻（I）。（d）简图（冠状观）显示了外科手术发现Waldeyer隐窝（淡灰色区域）长约10cm，该例于 CT检查后2小时进行了剖腹手术，术中发现从Treitz 韧带下70cm开始，350cm长的绞窄小肠肠襻。因为复位后的小肠呈紫色，所以没有行切除术，而做了空肠造瘘术。
肠系膜疝
Anatomy
解剖
The small bowel mesentery is a broad, fan-shaped fold of peritoneum that suspends the loops of the small intestine from the posterior abdominal wall (1,22). The two layers of peritoneal reflection form the mesentery, which extends from its origin at the ligament of Treitz to the right toward the ileocecal valve (Fig 1, D).
小肠系膜是比较宽广的扇形腹膜皱襞，将小肠肠管悬挂于后腹壁。肠系膜的两层反折腹膜从Treitz韧带起点向回盲瓣右侧延伸。
Nearly 35% of transmesenteric hernias occur during the pediatric period and are probably caused by a congenital mechanism. Mesenteric defects are usually 2–5 cm in diameter and are located close to the ligament of Treitz or the ileocecal valve (2,3). Three etiologic hypotheses have been proposed for congenital mesenteric defects: (a) partial regression of the dorsal mesentery, (b) fenestration during the developmental enlargement of an inadequately vascularized area, and (c) an ileocecal mesentery with considerable and rapid lengthening in fetal life (32). In adults, most mesenteric defects are probably the result of surgery, trauma, or inflammation.
近35%的肠系膜疝发生在儿童时期，可能是由于先天性原因导致。肠系膜上的缺损直径通常在2-5cm，位于邻近Treitz韧带或回盲瓣处。有人提出3种先天性肠系膜缺损的可能病因：（a）背侧肠系膜的部分退化；（b）乏血区的扩大导致裂孔形成；（c）回盲部肠系膜在胎儿期快速的延长。成人中大多数的肠系膜缺损可能是由于手术、创伤或感染导致。
作者: 丁香园集体创作
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