十二指肠旁疝
Anatomy
解剖
Paraduodenal fossae originate as congenital peritoneal anomalies owing to failure of mesenteric fusion with the parietal peritoneum and an associated abnormal rotation during imprisonment of the small intestine beneath the developing colon (1–3,22,27–33).
十二指肠旁隐窝的产生是由于先天性的腹膜异常，即肠系膜与壁层腹膜融合失败，同时小肠在局限于整条结肠中间位置的发育过程中旋转异常。
In the past, nine different fossae in the vicinity of the duodenum have been described, but clinically just five fossae are important: the superior duodenal fossa, inferior duodenal fossa (fossa of Treitz), paraduodenal fossa (fossa of Landzert), intermesocolic fossa (fossa of Broesike), and mesentericoparietal fossa (fossa of Waldeyer) (27,28). Figure 4 shows the locations of these fossae and their frequencies at autopsy. The fossa of Landzert, present in about 2% of autopsies, is recognized as inducing left paraduodenal hernia (PDH). The fossa of Waldeyer, present in about 1% of autopsies, is recognized as inducing right PDH (22).
以前，文献报道有9个十二指肠附近的隐窝，但临床上仅5个比较重要，分别是十二指肠上隐窝、十二指肠下隐窝、十二指肠旁隐窝（Landzert隐窝）、结肠系膜间隐窝（Broesike隐窝）和空肠旁隐窝（Waldeyer隐窝）。图4显示了这些隐窝的位置和其尸检的检出率。Landzert隐窝尸检的检出率约2%，易引起左侧十二指肠旁疝（PDH）。Waldeyer隐窝的尸检检出率约1%，易引起右侧PDH。
Figure 4. Drawing (coronal view) shows the locations of duodenal fossae. Arrows indicate the directions of hernias through these fossae. The frequency with which each fossa is found at autopsy is given in parentheses. 1 = superior duodenal fossa (50%), 2 = inferior duodenal fossa (fossa of Treitz) (75%), 3 = paraduodenal fossa (fossa of Landzert) (2%), 4 = intermesocolic fossa (fossa of Broesike), 5 = mesentericoparietal fossa (fossa of Waldeyer) (1%). (Adapted and reprinted, with permission, from reference 6.)
图4. 彩图（冠状观）显示了十二指肠隐窝的位置。箭头表示疝囊疝入这些隐窝的方向。圆括号内是尸检发现每个隐窝的检出率。1＝十二指肠上隐窝（50%），2＝十二指肠下隐窝（即Treitz隐窝，75%），3＝十二指肠旁隐窝（Landzert隐窝，2%），4＝结肠系膜间隐窝（即Broesike隐窝），5＝空肠旁隐窝（Waldeyer隐窝，1%）。（经作者同意，改编和翻印自参考文献6。）
Features特征
PDHs constitute approximately 53% of all internal hernias. Approximately three-fourths of these hernias occur on the left and are more predominant in men than in women, with a ratio of about 3:1 (1–3).
十二指肠旁疝占所有腹内疝的53%，大约四分之三发生于左侧，男性比女性明显好发，两者的比率约3∶1。
Left PDH develops through the fossa of Landzert into the descending mesocolon and left of the transverse mesocolon and results from failure of fusion of the inferior mesentery to the parietal peritoneum (29). The fossa of Landzert is located at the duodenojejunal junction, which is a zone of confluence of the descending mesocolon, transverse mesocolon, and small bowel mesentery (30). The herniated small bowel loops may become entrapped within this mesenteric sac. The characteristic CT appearance consists of an abnormal cluster or saclike mass of dilated small bowel loops lying between the pancreas and stomach to the left of the ligament of Treitz (Fig 5). There is usually mass effect that displaces the posterior wall of the stomach, the duodenal flexure inferiorly, and the transverse colon inferiorly (30,31). The mesenteric vessels that supply the herniated small bowel segments are crowded, engorged, and stretched at the entrance of the hernial sac (Fig 6 ) (9,10). Because the anterior wall of the sac contains the inferior mesenteric vein and left colic artery, CT demonstrates these vessels as a landmark above the encapsulated bowel loops.
由于肠系膜与壁腹膜融合失败，可发生左侧十二指肠旁疝，脏器穿过Landzert隐窝进入降结肠系膜和左侧横结肠系膜。Landzert隐窝位于十二指肠与空肠的交接处，该处降结肠系膜、横结肠系膜和小肠系膜发生融合，小肠会疝入这个肠系膜隐窝。CT表现的特征是十二指肠悬韧带左侧，胰和胃之间见囊状成簇扩张的小肠肠襻（图5），并由于重力作用压迫胃后壁、下方的十二指肠弯曲处和横结肠。供应疝囊内小肠的肠系膜血管在疝囊入口处群集、充盈和拉长（图6）。因为疝囊的前壁包含肠系膜下静脉和左结肠动脉，所以这些血管可作为CT区分疝囊内外的肠管的界标。
Figure 5. Left PDH in a 72-year-old man with acute, intermittent epigastric pain of 24 hours duration. (a) Contrast-enhanced CT scan of the upper abdomen shows a saclike mass of dilated jejunal loops between the pancreatic head (P) and stomach. The descending mesocolon (D) and stomach are displaced laterally. The dilated inferior mesenteric vein is located at the anterior border of the encapsulated loops. (b) CT scan obtained 20 mm below a shows crowded and engorged mesenteric vessels (arrow) at the fossa of Landzert (L). J = jejunal loops, S = stomach, arrowhead = inferior mesenteric vein. (c) CT scan of the midabdomen shows the inferior mesenteric vein (arrowhead). This vessel is a landmark for the inferior mesocolon, which is located at the anteromedial border of the encapsulated jejunal loops (J). (d) Diagram (coronal view) of the surgical findings shows that the fossa of Landzert is 4 cm in diameter (arrowheads). At laparotomy performed 42 hours after CT, approximately 200 cm of viable jejunum was found (arrows).
图5. 一例72岁男性左侧十二指肠旁疝，阵发性剑突下剧痛24小时。 (a) 上腹部增强CT扫描显示胰头(P)和胃之间见囊状成簇扩张的空肠，降结肠系膜和胃被推移到侧方，扩张的肠系膜下静脉是疝囊内肠襻的前界。(b) 20mm下方CT显示Landzert隐窝 (L)群集和充盈的肠系膜血管（箭头）。J =空肠，S =胃，箭头=肠系膜下静脉。(c)中腹部CT扫描肠系膜下静脉（箭头）。CT显示了下腹部的结肠系膜血管，可作为疝囊的空肠肠襻(J)的前内侧边界界标。(d) CT检查后42小时进行了剖腹手术，简图（冠状观）显示Landzert隐窝长约4cm（三角形箭头），疝囊内见长约200mm的存活空肠肠襻（长箭头）。
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