降结肠系膜旋转不良影像学特征及其对腹腔镜结直肠手术影响对策研究(附16例报告及文献复习)

Radiological features and colorectal surgery strategy of persistent descending mesocolon:report of 16 cases and literature review

目的探讨降结肠系膜旋转不良(PDM)的影像学特征、PDM对腹腔镜结直肠癌(低位)前切除手术的影响及对策。方法回顾性分析同一术者于2019年1月至2021年12月在中国医学科学院肿瘤医院和北京大学第一医院收治的行直肠(低位)前切除手术的16例PDM病人的临床资料;使用增强CT后处理的多平面重组(MPR)技术和最大投影密度(MIP)技术来诊断及分析PDM的影像学特征;采用肠管悬吊法显露直肠后间隙,通过头侧中间入路解剖肠系膜下动脉(IMA),并对其手术结局进行初步分析。结果16例合并PDM的结直肠癌病人占同期520例手术的3.1%(16/520),其中男性13例,女性3例,中位年龄58.5岁,中位体重指数25.3。应用MPR-MIP技术测量PDM相关影像学指标,其主要表现为:IMA偏向腹主动脉左侧为9例(56.3%),偏向右侧为7例(43.7%);肠系膜下动脉分型为Ⅰ型5例(31.2%),Ⅱ型3例(18.8%),Ⅲ型8例(50.0%);IMA至左结肠动脉的中位距离为1.7 cm(0.9,2.2),IMA至边缘血管弓距离为3.2 cm(1.7,3.8),IMA至结肠壁4.0cm(2.6,4.9)。围手术期结果为:1例(6.3%)病人中转开放手术处理IMA;4例(25.0%)因边缘血管弓损伤致肠管缺血被迫游离脾曲;2例(12.5%)病人术后出现吻合口漏。结论降结肠右侧缘位于左肾门内侧可作为PDM诊断的标准;CT后处理MPR和MIP技术可快速、准确评估PDM病人IMA分型及血管变异,可为腹腔镜手术提供参考。采用肠管悬吊法显露直肠后间隙和头侧中间入路解剖IMA可降低PDM病人中转开放手术和边缘血管弓损伤的风险,从而提高手术安全性。

Objective this study aims to understand the radiological features of persistent descending mesocolon(PDM) and to explore its effect and corresponding surgical strategy on laparoscopic anterior resection of colorectal cancer. Methods The clinical data of 16 patients with PDM who underwent(low) anterior resection in Cancer Hospital of the Chinese Academy of Medical Sciences and the First Hospital of Peking University were retrospectively collected from January 2019 to December 2021. Multi-planar reconstruction(MPR) and maximum intensity projection(MIP) were used to diagnose PDM and analyzed its radiological features. Bowel suspension is used to expose the retro-rectal space. The cephalic intermediate approach was used to dissect the inferior mesenteric artery(IMA). Finally, the surgical outcomes were analyzed. Results 16 patients with PDM accounted for 3.1% of 520 patients with colorectal surgery, including 13 males(76.0%) and 3 females(24.0%) with a median age of 58.5 years and a median body mass index of 25.3. The MPR-MIP technique was used to measure PDM-related imaging variables. The main manifestations were as follows: IMA shifted to the left side of the abdominal aorta in 9 cases(56.3%) and to the right side in 7 cases(43.7%). The bifurcation patterns of IMA were as follows: type Ⅰ in 5 cases(31.2%), type Ⅱ in 3 cases(18.8%), and type Ⅲ in 8 cases(50.0%). The median length from IMA to the left colic artery(LCA)was 1.7 cm(0.9,2.2), from IMA to the marginal arch was 3.2 cm(1.7,3.8),and from IMA to the colon wall was 4.0 cm(2.6,4.9). One case(6.3%) was conversion to dissect IMA. 4 patients were forced to free the spleen flexure due to marginal artery injury and intra-operative bowel ischemia. Anastomotic leakage occurred in 2 patients(12.5%) postoperatively. Conclusion The sign of the right border of descending colon located inside the left renal hilum can be used as a diagnostic criterion for PDM. MPR and MIP techniques of CT post-processing can efficiently and accurately assess bifurcation patterns of IMA and vascular variation in PDM patients, and further assist laparoscopic rectal surgery. Dissection of IMA by bowel suspension through retro-rectal space and cephalic intermediate approach can reduce the risk of conversion and marginal arch injury in patients with PDM, and thereby improve surgical safety.