通过测量中低位直肠癌骨盆CT扫描图像数据，探讨影响腹腔镜全直肠系膜术难易程度的影像学因素。

回顾性分析92例在2016年4月至2018年5月接受腹腔镜全直肠系膜切除的中低位直肠癌患者的临床资料。在薄层CT扫描冠状位、矢状位和横断面图像上测得10项骨盆因素数据。收集患者临床相关资料，以手术时间、术中失血量、术后住院天数及术后并发症作为评价手术难易程度的指标。采用单因素分析和多因素分析评估骨盆相关数据对手术难易程度的影响。

92例患者平均手术时间为（230.8±74.8）min；术中失血量为50 mL（5~400 mL）；术后中位住院时间10（6~45）天；术后并发症14例（15.2%），其中吻合口漏3例，肠梗阻4例，吻合口狭窄2例，术后腹腔出血1例，尿瘘1例，肠系膜淋巴管瘘1例，腹壁切口疝1例，造口旁疝1例。10项骨盆数据中9项具有性别差异。单因素分析提示手术时间与骶尾间距（P=0.027）、坐骨棘径（P=0.044）存在相关性，术后住院时间与中骨盆前后径（P=0.007）、出口前后径（P=0.020）存在相关性。多重线性回归分析提示长骶尾间距（P=0.020）是延长手术时间的危险因素。Logistic回归分析提示短中骨盆前后径（OR=0.406，P=0.019）、长耻骨联合上下径（OR=3.432，P=0.038）是术后住院天数增加的危险因素。术后并发症、术中失血量与骨盆或相关临床数据无关。

中低位直肠癌患者中，骶尾间距长、耻骨联合上下径长、中骨盆前后径短者，行腹腔镜前切除术手术难度较大。术前全面评估中低位直肠癌患者的骨盆因素可作为手术难度的评价指标。

We measured pelvic dimensions by CT scanning to explore pelvic factors affecting the surgical difficulty of laparoscopic anterior resection for middle and low rectal cancer.

This study performed a retrospective analysis on 92 patients with middle and low rectal cancer who underwent laparoscopic total mesorectal excision from April 2016 to May 2018. Ten pelvic factors were measured in coronal, sagittal and cross-sectional CT images. We also collected relevant clinical data of the patients. The operation time, intraoperative blood loss, length of postoperative stay and postoperative complications were used as dependent variables to evaluate the technical difficulty of the operation. We used univariate analysis and multivariate analysis to analyze the influence factors of pelvic size and related clinical data on surgical difficulty.

The mean and standard deviation of operation time of 92 patients was (230.8±74.8) min. The median and range of intraoperative blood loss was 50 (5~400) mL and lengths of postoperative stay was 10 (6~45) days; Postoperative complications were 14 patients (15.2%), including 3 patients with anastomotic fistula, four patients with intestinal obstruction, two patients with anastomotic stenosis, one patient with postoperative abdominal bleeding, one patient with urinary fistula, one patient with mesenteric lymphatic fistula, one patient with abdominal incisional hernia and one patient with paracostomy hernia. Sex differences were found in 9 pelvic data. Univariate analysis suggested that operation time was correlated with S1-to-coccyx vertical diameter (P=0.027), S1-to-S5 vertical diameter (P= 0.044); length of postoperative stay was correlated with middle pelvic anteroposterior diameter (P=0.007) and outlet anteroposterior diameter (P=0.020). Multiple linear regression analysis suggested that long S1-to-coccyx vertical diameter (P=0.02) and preoperative chemoradiotherapy (P=0.015) were factors for long operation time. Logistic regression analysis indicated short middle pelvic anteroposterior diameter (P=0.019, OR= 0.406) and long symphyseal height (P=0.038, OR=3.432) were the factors of long postoperative hospital stay. Complications and intraoperative blood loss were not correlated to the pelvic dimensions or clinical data.

Patients with long S1-to-coccyx vertical diameter, long symphyseal height and short middle pelvic anteroposterior diameter performed laparoscopic anterior resection more difficultly. Identification of pelvic factors in patients with low and middle rectal cancer can evaluate the surgical difficulty of laparoscopic anterior resection.