Diagnosis of Cervical OPLL in Lateral Radiograph and MRI: Is it Reliable?

OBJECTIVE Cervical OPLL is a relatively common cause of developing cervical myelopathy or radiculopathy in Asians. Cervical OPLL is sometimes missed in lateral radiography or MRI. In the present study, we analyzed the diagnostic accuracy of cervical OPLL in lateral radiography and MRI compared to CT scan. METHODS This is a retrospective study of forty-six patients who underwent decompressive surgery anteriorly or posteriorly in our institute. All patients were diagnosed with cervical OPLL by CT scan. The patients were grouped into continuous type, segmental type, mixed type, and localized type. We then evaluated lateral radiographs and MRI compared to CT scans. The diagnostic accuracy and false negative rates in lateral radiograph and MRI were evaluated. RESULTS In a total of 46 patients diagnosed with cervical OPLL in CT scans, diagnostic accuracy using lateral radiograph and MRI were 52.2%(24/46) and 58.7%(27/46), respectively. In the continuous type group, diagnostic accuracy using lateral radiograph and MRI were 85.7%(6/7) and 100.0%(7/7). In the segmental type group, diagnostic accuracy using lateral radiograph and MRI were 27.3%(6/22) and 31.8%(7/22). In the mixed type group, diagnostic accuracy was 91.7%(11/12) in lateral radiograph and 83.3%(10/12) in MRI. In the localized group, diagnostic accuracy was 20.0%(1/5) in lateral radiograph and 60.0%(3/5) in MRI. CONCLUSION The diagnostic accuracy of cervical OPLL using lateral radiograph and MRI was less than using CT scan. For the best treatment plan, preoperative CT scan should be performed to detect conditions of ossifications such as cervical OPLL.