螺旋CT三维重建在小儿髋臼发育不良中的作用

Application of spiral CT three dimentional reconstruction on developmental dysplasia of the hip in children

目的探讨螺旋CT三维表面遮盖重建(SSD)在小儿髋臼发育不良中的应用价值。方法采用美国Picker2000S螺旋CT扫描装置对39例单侧先天性髋脱位患儿行骨盆三维重建。全部患儿均为女性,平均年龄4.3岁(3.5～8岁)。其中先天性髋关节半脱位17例,全脱位22例。分别测量:(1)健侧、患侧髋臼的深度和表面积;(2)健侧、患侧髋臼底最低点(O点)分别至髋臼前柱外缘前端(A点)、髋臼顶中点(B点)、髋臼后柱外缘后端(C点)的距离。结果先天性半脱位患儿健侧髋臼深度为(23.89±1.56)mm,患侧为(21.25±1.25)mm,双侧比较差异有显著性意义(P<0.05)。全脱位患儿健侧髋臼深度为(24.67±1.43)mm,患侧为(20.76±1.12)mm,双侧比较差异有显著性意义(P<0.05)。半脱位患儿健侧髋臼表面积为(27.78±1.65)mm2,患侧为(24.25±2.72)mm2,双侧比较差异有显著性意义(P<0.05)。全脱位患儿健侧髋臼表面积为(28.26±2.25)mm2,患侧为(24.54±2.51)mm2,双侧比较差异有显著性意义(P<0.05)。全脱位患儿OA,OB,OC距离健侧分别为(46.92±4.07)mm、(55.65±4.34)mm和(64.36±5.21)mm,患侧为(40.73±4.28)mm、(44.28±6.43)mm和(48.09±4.85)mm,双侧比较差异有显著性意义。半脱位患儿OA,OB,OC距离健侧分别为(47.68±3.98)mm、(54.25±3.34)mm和(12.96±4.65)mm。

Objective To evaluate the value of surface shaded reconstruction (SSD) of CT scanning on developmental dysplasia of the hip (DDH). Methods Unilateral DDH in 39 cases was examined with Picker 2000S spiral CT to perform SSD of the affected pelvis. All patients were females with the age ranging from 3.5 to 8 years old (average 4.25 years). Of 39 cases, 22 cases were complete dislocation the hip, 17 cases were subluxation of the hip. The measurement on SSD included of the depth and surface area of normal and affected acetabulum; the distances from the lowest point of the bottom of the acetabulum (O point) to the anterior end (A point) of the lateral margin of anterior acetabular column (OA), the middle point (B point) of the acetabular roof (OB) and the posterior end (C point) of lateral margin of the posterior acetabular column (OC). Results In normal hip, the medial and lateral margin of the acetabular roof was overlapping, and in DDH, a bony defect was found in the lateral acetabular margin in three-dimensional CT scanning. The depth of the dysplastic hip with subluxation and the normal hip was (21.25±1.25)mm and (23.89±1.56)mm respectively with significant difference(P<0.05).The depth of the dysplastic hip with complete dislocation and the normal hip was (20.76±1.12) mm and (24.67±1.43) mm respectively with significant difference(P< 0.05). The surface area of the affected hip with subluxation and the normal one was (24.54±2.72) mm2 and (27.78±1.65) mm2, and the surface area of the affected with complete dislocation and the opposite hip was (24.54±2.51)mm2 and (28.26±2.25) mm2. The OA, OB and OC of the hip with complete dislocation were (40.73±4.28) mm, (44.28±6.43) mm and (48.09±4.85) mm, and the OA, OB and OC of the normal hip were (46.92±4.07) mm, (55.65±4.34) mm and (64.36±5.21) mm respectively.The OA, OB and OC of the hip with subluxation were (45.15±3.24) mm, (47.78±4.56) mm and (58.14±4.12) mm, and the OA, OB and OC of the normal hip were (47.68±3.98) mm, (54.25±3.34) mm and (12.96±4.65) mm respectively. There was no significant difference between the bilateral hips. Conclusion SSD of three-dimensional CT reconstruction is an effective method in overviewing exactly the acetabular bony deficiency and pattern in DDH. In patients with subluxation, the deficiencies of the acetabulum lie superiorly, at the top of the acetabulum. The deficiency of the acetabulum is mostly on the lateral margin of the acetabular roof; while the hip suffering form complete dislocation, the whole acetabulum is displastic. The data suggests that the reconstruction with pelvic osteotomy should be based on individual condition of acetabular deformity to improve the containment of the hip joint.