Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh, India.
Turk Neurosurg. 2024;34(5):898-906. doi: 10.5137/1019-5149.JTN.45091-23.2.
To establish the diagnosis of basilar invagination (BI) on the basis of specific bony landmarks Klaus' index (KI), perpendicular distance between the tip of the odontoid process and palato internal occipital protuberance (PI) line.
Forty-nine patients were analysed, who underwent surgery for BI, between July 2020 and June 2023. Radiological assessment was done in all the patients using reconstructed midsagittal images on computed tomography scans .
Mean age was 34.82 ± 10.52 years with male preponderance (67.35%) in patients with BI. We also analysed randomly selected 120 control subjects (male: female = 59:61) with mean age 43.5 ± 14.08 years. The mean distance of tip of the odontoid process from PI line in patients with BI was 3.39 ± 3.09 mm. The mean value of KI in the patients with BI was 28.57 ± 1.68 mm. Receiver operating characteristic (ROC)curve was used for analysing the distance of the tip of the odontoid process from PI line in the patients with BI which produced area under curve( AUC) of 0.97 (confidence interval [CI] -0.931 to 0.990, p < 0.0001). Cut-off point of 7.5 mm was identified for the distance of tip of odontoid process from PI line with sensitivity of 89.8% and specificity of 97.5% having 95.27% diagnostic accuracy for BI. ROC curve analysis of value of KI for the diagnosis of BI produced AUC of 1( CI: 0.978 to 1.000, p < 0.0001). Cut-off value of 33.2 mm for KI was identified for diagnosing BI with 100% accuracy.
The distance of tip of the odontoid process from PI line < 7.5 mm and value of KI < 33.2 mm, both of these parameters can diagnose BI with comparable accuracy to most widely used conventional radiological methods.
基于 Klaus 指数（KI）和寰椎尖与腭内枕骨隆突（PI）线之间的垂直距离这两个特定的骨性标志，建立颅底凹陷症（BI）的诊断标准。
对 2020 年 7 月至 2023 年 6 月间因 BI 而行手术治疗的 49 例患者进行回顾性分析。所有患者均在 CT 扫描重建的正中矢状位图像上进行影像学评估。
BI 患者的平均年龄为 34.82±10.52 岁，男性占优势（67.35%）。我们还随机分析了 120 名对照组（男：女=59:61），平均年龄为 43.5±14.08 岁。BI 患者寰椎尖与 PI 线的平均距离为 3.39±3.09mm。BI 患者的 KI 均值为 28.57±1.68mm。我们使用受试者工作特征（ROC）曲线分析 BI 患者寰椎尖与 PI 线的距离，其曲线下面积（AUC）为 0.97（95%置信区间为 0.931 至 0.990，p<0.0001）。我们确定了 7.5mm 作为寰椎尖与 PI 线距离的截断点，其具有 89.8%的敏感性和 97.5%的特异性，对 BI 的诊断准确率为 95.27%。ROC 曲线分析 KI 值对 BI 的诊断得出 AUC 为 1（95%置信区间为 0.978 至 1.000，p<0.0001）。我们确定了 KI 的截断值为 33.2mm，用于诊断 BI，其准确率为 100%。
寰椎尖与 PI 线的距离<7.5mm 和 KI 值<33.2mm 这两个参数都可以与最广泛使用的传统影像学方法一样准确地诊断 BI。
