眼眶爆裂性骨折眶腔容积改变与眼球内陷相关性的CT测量研究

Correlation between orbital volume on CT and enophthalmos in blow-out fracture

目的通过测量眼眶爆裂性骨折病人患眼眼眶容积的改变量及眼球内陷的程度,研究眼眶容积改变量与眼球内陷量的相关性;应用CT影像及Hertel眼球突出计测量眼球突出度并就两种方法进行对比。方法选取40例单侧眼眶骨折病人,其中22例为早期组,就诊时间为伤后3d内,不伴眼球内陷;18例为晚期组,就诊时间为受伤2周后,伴眼球内陷。对早期组病人分别于伤后1周内、2周、3周进行眼眶CT扫描,测量其双眼眼眶容积及眼球突出度,记录眼球内陷发生的时间;对晚期组病人利用CT影像测量双眼眼眶容积,使用CT影像及Hertel眼球突出计两种方法对比测量眼球突出度。所有测量均以正常眼为对照。用SPSS17.0软件进行数据处理,采用配对t检验、重复测量的方差分析、相关分析与线性回归等统计学方法进行分析。结果①全部40例眼眶骨折病人患眼的眶腔容积较对照眼均有明显增大(t=-3.502,P<0.01)。②早期组病人1周内开始出现眼球内陷,第2周眼球内陷较第1周增多明显。③早期组病人1周内、2周、3周时的眼眶容积増大量差异无统计学意义。④晚期组病人眼眶容积增加量与眼球内陷量呈高度正相关性,相关系数为0.973。眼眶容积增加量(y)与眼球内陷量(x)之间具有相关性,回归方程为y=0.057+0.829x(P<0.05)。⑤晚期组病人使用CT测量眼球突出度与使用Hertel眼球突出计所得的差异有统计学意义(P<0.05)。结论①眼球内陷通常于伤后2周后出现。②伤后早期眶周组织的水肿对眼眶容积的改变无明显影响。③眼眶爆裂性骨折病人患眼眶腔容积増大量与眼球内陷量呈高度正相关性,在外伤后早期对眼眶容积进行CT测量,可预测外伤后发生眼球内陷的可能性和程度。④使用CT测量眼球突出度结果大于使用Hertel眼球突出计测量值,排除了人为因素及皮肤、结膜的影响,测量结果更为精确。

Objective To explore the evolution of orbital volume on CT and enophthalmos in patients with blow-out fracture, to study the relationship between orbital volume change and degree of enophthalmos, and to compare the accuracies of CT and Hertel in evaluating the degree of the enophthalmos. Methods 40 patients with unilateral blow-out fracture of single eye were selected and divided into early stage group （22 cases, within three days, without enophthalmos） and late stage group （18 cases, over two weeks, with enophthalmos）. In early stage group, the orbital volumes were measured with CT. The time and degree of enophthalmos were observed in the first, second and third week after injury. In late stage group, the orbital volumes were measured with CT. The degree of enophthalmos was measured with both Hertel exophthalmometer and CT. All measurements were using their normal orbital as controls. Statistic analysis was carried out with SPSS 17.0, including the paired t test, Chi-square test, correlation analysis and linear regression. Results 1 The orbital volumes of 40 patients with blow-out fracture were significantly increased comparing with those of normal controls .2 In the early stage group, there were significant differences in presence of enophthalmos between the first week and the other two weeks. 3 In the early stage group, the orbital volumes were not significantly different among the three time points. 4 There was significant linear correlation between the enlargement of orbital volume and the degree of enophthalmos. The linear regression equation of enophthalmos （y） and the enlargement orbital volume （x） was： y=0.057＋0.829x （P〈0.01）, with each 1.0 cm3 enlargement in the orbital volume causing approximately 0.886 mm enophthalmos. 5 In the later stage group, the degree of the enophthalmos measured on CT was significantly higher than that of Hertel in （1.53~0.73 mm）. Conclusions 1 Enophthalmos usually appears after the second week of injury. 2 The edema of periorbital tissue in the early stage has no significant influence on the enlargement of the orbital volume. 3 The ipsilateral orbital volume is significantly increased comparing with that of normal eontralateral side. The orbital volume linearly correlates to the degree of enophthalmos. The orbital volume measurement on CT in the early stage of injury may predict the occurrence and the final degree of enophthalmos. 4 CT exophthalmos degree was higher than that of Herlel. The former is more precise than Hertel by removing the influences of human factors, such as skin and conjun（.,tiva etc.