Background

In invasive examinations of the colon, e.g. colonoscopy, the tortuosity of the colon is a crucial factor for successful completion of the procedure. If adjacent segments of the colon bend at acute angles (under 90°), endoscopy may become difficult and troublesome.

Methods

We retrospectively enroled 227 individuals (96 female, 131 male) who underwent abdominopelvic computed tomography examination. For inclusion, subjects were required to have a negative history for colonic disease and abdominopelvic surgery. We measured the angle between the descending colon and the proximal part of the sigmoid (in degrees). In addition, the position of the descending-sigmoid flexure was assessed in relation to the left anterior superior iliac spine, the median plane, and anterior aspect of the 5th lumbar vertebra (in mm). The study protocol was reviewed and approved by the local ethics committee.

Results

We visualised the descending-sigmoid flexure in all 227 subjects. In one third of cases, the flexure formed an angle smaller than/or 90°. In females, this landmark (mean ± standard deviation) was located 30.2 ± 8.4 mm from the left anterior superior iliac spine, 88.6 ± 14.2 mm from the median plane, and 115.4 ± 21.4 mm from the anterior aspect of the 5th lumbar vertebra. In males, the dimensions were: 32.1 ± 12.8 mm, 97.6 ± 15.8 mm, and 123.9 ± 22.9 mm, respectively. This landmark distance remained constant from the left anterior superior iliac spine regardless of subject age, height and weight. The other measured distances were related to age, height, weight or BMI.

Conclusions

The descending-sigmoid flexure is an important landmark in large intestine morphology situated approximately width of two fingers (3 cm) from the left anterior superior iliac spine and one hand width (9–10 cm) from the median plane. In approximately one third of the subjects, the flexure formed an angle of less than/or 90°, which can cause a problem during colonoscopy.

中文翻译：

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降乙状结肠曲 - 一个重要但令人惊讶地被忽视的里程碑

背景

在结肠的侵入性检查中，例如结肠镜检查，结肠的弯曲度是成功完成手术的关键因素。如果结肠的相邻部分以锐角（低于 90°）弯曲，内窥镜检查可能会变得困难和麻烦。

方法

我们回顾性招募了 227 名接受腹盆腔计算机断层扫描的人（96 名女性，131 名男性）。为了纳入，受试者必须具有结肠疾病和腹盆腔手术的阴性病史。我们测量了降结肠和乙状结肠近端部分之间的角度（以度为单位）。此外，还评估了与左髂前上棘、正中平面和第 5 腰椎前部（mm）相关的降乙状屈曲的位置。研究方案经当地伦理委员会审查和批准。

结果

我们可视化了所有 227 名受试者的降 sigmoid 屈曲。在三分之一的情况下，弯曲形成的角度小于/或 90°。在女性中，该界标（平均值 ± 标准差）位于距左髂前上棘 30.2 ± 8.4 mm、距正中平面 88.6 ± 14.2 mm 和距第 5 腰椎前部 115.4 ± 21.4 mm 的位置。在男性中，尺寸分别为：32.1 ± 12.8 毫米、97.6 ± 15.8 毫米和 123.9 ± 22.9 毫米。无论受试者的年龄、身高和体重如何，该标志性距离与左髂前上棘保持恒定。其他测量的距离与年龄、身高、体重或 BMI 相关。

结论

乙状结肠降曲是大肠形态学的一个重要标志，距左髂前上棘约两指宽（3 cm），距正中平面约一手宽（9-10 cm）。在大约三分之一的受试者中，弯曲形成的角度小于/或 90°，这可能会在结肠镜检查期间造成问题。