载距突轴向X线投照的影像解剖学研究

目的 探讨载距突轴向X线投照技术,为判断跟骨骨折内固定置钉质量提供依据。方法 选取45侧成人足踝标本(标本组)行足踝X线摄片、多层螺旋CT(MSCT)扫描及3D重建,然后行解剖观测;收集2014年7月—2017年6月南京鼓楼医院集团宿迁市人民医院成人足踝侧位X线影像资料225例(X线组)进行回顾性分析,其中男132例、女93例,年龄18～72(42.6±11.7)岁。借助形态解剖和MSCT 3D图像观察标本载距突形态,分析载距突与内踝、距骨、舟骨解剖关系,研究内踝、距骨、舟骨对载距突轴向X线投照影响。以足底平面为参照面,测量标本的载距突长、宽、高和前倾角;在临床X线图像上测量载距突前倾角,比较各组前倾角差异,分析载距突与轴向投照角之间关系,确定载距突轴向投照角。按照简单随机抽样法随机抽取标本组5例标本行实验置钉,2017年1—6月对我院10例跟骨骨折患者手术置钉,用载距突轴向X线投照法分析置钉效果。结果 标本解剖和MSCT图像观察表明,载距突位于跟骨内侧,高出跟骨前部的上面并向内侧延展,呈后上-前下倾斜,与内踝、距骨、舟骨之间具有密切的解剖关系。但在轴线方向,仅有距骨后突与载距突重叠,影响载距突轴向X线投照效果。标本组载距突平均长(24.36±2.25)mm、宽(14.91±1.58)mm和高(11.03±1.24)mm。标本组载距突前倾角分别为解剖测量30.38°±1.21°、MSCT测量30.47°±1.54°和X线测量30.17°±1.44°,X线组男性与女性载距突前倾角分别为30.09°±1.82°和30.52°±1.62°;组间比较差异均无统计学意义(F=1.768, P>0.05),表明不同研究方法获得结果一致,确定载距突前倾角约为30°,此角度即为载距突轴向X线投照角。应用轴向X线投照法判断实验和临床载距突置钉情况,成像效果较为满意。结论 载距突轴位X线成像能显示载距突长轴方向的前后位影像,及中距关节面,可用于跟骨骨折内固定术中透视和术后摄片分析螺钉置入效果,为载距突相关临床影像学检查提供了新视角。

Imaging anatomic study on axial X-ray projection of sustentaculum tali

Objective To explore the axial X-ray projection technique of sustentaculum tali for observing the effect of screw implantment of calcaneal fractures.Methods Forty-five adult specimens of ankle and foot (specimen group) were chosen to research by X-ray, multi-slice spiral computed tomography(MSCT) scan and reconstruction on ankle and foot, and then they were dissected and observed . From July 2014 to June 2017, the People's Hospital of Suqian, a total 225 patients (X-ray group) with lateral X-ray image of ankle and foot were collected and analyzed, retrospectively, there were 132 male patients and 93 female patients, with an average age of 42.6±11.7(range from 18 to 72 years old). Morphological characteristics of sustentaculum tali on specimen were observed with the aid of traditional dissecting methods and MSCT 3D images. The anatomic relationship between sustentaculum tali with the medial malleolus, talus and navicular bone were analyzed. The influencing factors of the axial X-ray projection effect of sustentaculum tali from medial malleolus, talus and navicular bone were studied. The plantar plane was used as anatomical reference plane, the length, the width, the height and anteversion angle of sustentaculum tali were measured. The sustentaculum tali's anteversion angles of male and female patients on X-ray image were also measured. The difference of anteversion angles between each group was compared. The relation between the anteversion angle and the axial projection angle of sustentaculum tali was analyzed, and the X-ray axial projection angle of sustentaculum tali was determined. Five cases of specimen group were randomly used for experimental screw placement. From January 2017 to June 2017, 10 patients with calcaneal fracture were surgical screw internal fixation, and the effect of screw implantment into sustentaculum tali was analyzed by using the axial X-ray projection technique of sustentaculum tali.Results Specimen dissection and MSCT 3D images observation showed that sustentaculum tali located on the medial side of calcaneus, above the anterior part of calcaneus and extended the medial surface, and it had a close anatomical relationship with medial malleolus, talus and navicular bone. However, in the axial direction of sustentaculum tali, only the posterior apophysis of talus was overlapped with sustentaculum tali, which influenced the effect of the axial X-ray projection of sustentaculum tali. The length, width, and height of sustentaculum tali on specimens were (24.36±2.25)mm, (14.91±1.58)mm, and (11.03±1.24)mm. The anteversion angles of sustentaculum tali on specimens were 30.38°±1.21° in anatomical measurement group, 30.47°±1.54° in MSCT measurement group and 30.17°±1.44° in X-ray measurement group, respectively. The sustentaculum tali's anteversion angles of X-ray groups in male and female were 30.09°±1.82° and 30.52°±1.62°, respectively. There was no significant difference of anteversion angles between each group (F=1.768, P＞0.05), which showed that different research methods obtained consistent results. The sustentaculum tali's anteversion angle was about 30°, and this angle was the axial X-ray projection of sustentaculum tali. Using the axial X-ray projection to detect the screw inserted into sustentaculum tali, which achieved satisfactory effect.Conclusions The axial X-ray radiography of sustentaculum tali can display the anteroposterior image of sustentaculum tali in long axis direction, and it also can show middle talar articular surface. This radiologic method can be used to the intraoperative X-ray fluoroscopy and the postoperative X-ray radiography for analyzing the effect of internal fixation with screw insertion of calcaneal fracture, which provides new perspectives for related clinical imaging findings of sustentaculum tali.