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Pericecal Hernia
盲肠旁疝
Anatomy
解剖

Embryologically, the anatomy of the cecal and pericecal peritoneum is not determined until the 5th fetal month, when the migration of the midgut is complete, with the cecum fixed in the right colic fossa and resorption of the peritoneal surfaces (39,40). Four different pericecal recesses formed by folds of the peritoneum have been reported: the superior ileocecal recess, inferior ileocecal recess, retrocecal recess, and paracolic sulci (Fig 12) (3,39,40,42).
胚胎发育中，胎儿5个月时盲肠和盲肠旁的腹膜解剖才明确，此时中肠移位完成，盲肠固定在右侧结肠隐窝，重新附着腹膜面。据报道，根据腹膜皱襞将盲肠旁隐窝分为4个：回盲上隐窝、回盲下隐窝、盲肠后隐窝和结肠旁沟（图12）。

Figure 12. Drawing (coronal view) shows the locations of pericecal recesses. 1 = superior ileocecal recess, 2 = inferior ileocecal recess, 3 = retrocecal recess, 4 = paracolic sulci. (Adapted and reprinted, with permission, from reference 41.)
图12 示意图显示盲肠旁疝的部位。1，回盲上隐窝；2，回盲下隐窝；3，盲肠后隐窝；4，结肠旁沟。

The superior ileocecal recess is bounded in front by the vascular fold of the cecum and behind by the ileal mesentery. The inferior ileocecal recess is bounded in front by the ileocecal fold, above by the posterior ileal surface and its mesentery, to the right by the cecum, and behind by the upper mesoappendix (22). The retrocecal recess, the largest of the four recesses, is bounded anteriorly by the posterior wall of the cecum, posteriorly by the posterior abdominal wall, superiorly by the reflection of the visceral peritoneum coating the posterior wall of the cecum, and medially and laterally by two cecal folds of the peritoneum (40). Paracolic sulci are lateral depressions of the peritoneum investing the cecum. These recesses may be absent or rarely extend posterior to the cecum, forming pockets large enough to admit several fingers (42).
Furthermore, according to the literature (43,44), supplementary recesses and fossae may develop in the ileocecal area because of individual variations in the processes of bowel rotation and peritoneal fusion. These structures may also become hernial orifices.
回盲上隐窝在盲肠血管襞前方和回肠系膜的后方。回盲下隐窝在回盲襞前方和回肠后表面及其系膜的下方，盲肠右侧，阑尾上系膜的后方。盲肠后隐窝是四个隐窝中最大的，位于盲肠后壁的前面，后腹壁的后方，覆盖盲肠后壁腹膜反折的上方，两盲肠襞的中侧方。结肠旁沟是腹膜侧方围绕盲肠的凹陷。这些隐窝不会或者很少向后延伸至盲肠，但其形成的“口袋”足以容纳数只手指。
另外，根据文献报道，由于在肠管旋转和腹膜融合过程中的个体差异，一些其他的附属隐窝或陷窝可延伸到回盲区，这些结构也可变成疝孔

Features
特征
Pericecal hernias account for 13% of all internal hernias. In most cases, ileal loops herniate through the defect and occupy the right paracolic gutter (Fig 13). Clinical diagnosis is difficult because clinical symptoms and physical examination usually indicate acute SBO, but in chronic incarceration diagnoses are confused with inflammatory bowel disease, appendiceal disorders, or other causes of SBO (4,39). In establishing the precise preoperative diagnosis, delayed radiographs from a small bowel series or barium enema examinations are considered to be helpful when the patient’s condition permits these examinations (1,3). The specific CT appearance of a pericecal hernia is not established, and there are few cases in the literature (40,42–44). In our two cases, CT scans demonstrated a cluster of fluid-filled small bowel loops (Fig 14) located lateral to the cecum and posterior to the ascending colon. In addition, a beaking appearance indicative of tethering at the aperture of the peritoneal recess and dilatation of small bowel loops with a transition zone were revealed. On the basis of these CT findings, pericecal hernia can be diagnosed with high certainty (40).
盲肠旁疝占所有腹内疝的13%，大多数病例中回肠经缺口疝出占据右侧结肠旁沟（图13）。临床的诊断有一定困难，尽管临床的症状和体格检查常可提示急性SBO，但在慢性绞窄时容易和炎性肠病、阑尾病变及其他原因引起的SBO相混淆。为了能做出准确的术前诊断，如果病人情况允许，进行小肠延迟X线检查或钡灌肠检查可能会有帮助。盲肠旁疝的特异性CT表现还没有确定，仅有几篇相关的文献报道。我们的这两例，CT扫描显示小肠堆集，肠管内液体积聚，位于盲肠的侧方和升结肠的后方。另外，还显示在腹膜隐窝裂隙处的鸟嘴征及其扩张的小肠肠管和过渡区。基于这些CT表现可以高度确定盲肠旁疝的诊断。

Figure 13. Pericecal hernia through the retrocecal recess in an 84-year-old man with colicky right lower quadrant pain and vomiting of 48 hours duration. He underwent an appendectomy at 54 years of age. (a) Contrast-enhanced CT scan of the midabdomen shows a cluster of encapsulated small bowel loops (arrowheads) in the lateral aspect of the right paracolic gutter and behind the ascending colon (A). Dilated and stretched mesenteric vessels (arrow) are seen within the cluster. (b) CT scan of the lower abdomen shows beaking and collapsed bowel loops (arrow) at the retrocecal recess (arrowhead). The ascending colon (A) is displaced anteriorly. Laparotomy was performed 12 hours after CT. (c) Diagram (coronal view) of the surgical findings shows that approximately 230 cm of gangrenous jejunum and ileum (arrows), located 120 cm from the ligament of Treitz, was herniated through the retrocecal recess (arrowheads). The gangrenous bowel loops were resected. A = ascending colon.
一84岁男性患者的经盲肠后隐窝的盲肠旁疝，表现为持续48小时的右下腹的疝气痛和呕吐。其54岁时曾进行过阑尾切除术。（a）中腹部的CT增强扫描显示右侧结肠旁沟侧方和升结肠（A）后方的小肠堆集包绕（短箭头），其内可见肠系膜血管扩张拉长（长箭头）。（b）下腹部CT扫描显示盲肠后隐窝（短箭头）处肠管塌陷呈鸟嘴征（长箭头）。升结肠（A）向前移位。CT扫描12小时后行剖腹术。(c)手术所见的示意图（冠状面）显示距Treitz韧带120cm的空肠和回肠（长箭头）有约230cm经盲肠后隐窝（短箭头）疝出发生坏疽。坏疽肠管被手术切除。