Cervical ossification of the posterior longitudinal ligament (OPLL) is a condition of abnormal calcification of the posterior longitudinal ligament, and a common cause of cervical myelopathy and radiculopathy, for which surgery is the most effective treatment. Anterior decompression can directly resect the ossified foci and achieve satisfactory results compared with posterior approach [1]. However, dural ossification (DO), which means the ossified mass may erode or fuse with the dura, was frequently encountered during OPLL cases. In this situation, anterior approach is difficult and risky, which may lead to dural defects (DDs) and cerebrospinal fluid leaks (CSFLs), causing threatening complications and disastrous sequela [2], [3], [4].

Presently, the challenge to overcome is to recognize signs of DO on preoperative images. Preoperative identification of DO and the occurrence of DDs can help surgeons adopt appropriate surgical strategies and intraoperative tactics dealing with CSFLs [5]. The safety of the anterior decompression will be largely ensured. The double-layer sign is the most classic imaging modality predicting DO and DDs [6], but several studies showed that its sensitivity and specificity are limited [7], [8]. Other imaging signs have also been reported. However, no validated system integrating these findings to assess the probability of imaging signs demonstrating an underlying risk of DDs. Furthermore, a robust classification system may lead to more standardized diagnostic and surgical approaches. Therefore, we aimed to define a scoring system based on the most reliable CT findings in patients with OPLL who have a surgically confirmed DDs.