Cervical myelopathy due to subaxial calcium pyrophosphate dihydrate (CPPD) deposition with simultaneous asymptomatic crowned dens syndrome: two case reports

BACKGROUND: There are few reports of cervical myelopathy caused by an attack of subaxial calcium pyrophosphate dihydrate (CPPD) deposition. Moreover, there has been no report on cervical myelopathy by subaxial CPPD deposition with simultaneous asymptomatic crowned dens syndrome (CDS) at the same time. CASE PRESENTATION: The first case was a 68-year-old male complaining of cervical myelopathic symptoms. Plain radiographs, computed tomography (CT) and magnetic resonance imaging (MRI) findings revealed spinal cord compression by calcified round lesions at C4 as well as a calcified lesion behind the dens. The second case was a 77-year-old female complaining of cervical myelopathic symptoms. Plain radiographs, CT and MRI findings revealed spinal cord compression by calcified round lesions at C3 and C4 as well as a calcified lesion behind the dens. In both cases, we believed that the calcified lesion behind the dens was an asymptomatic lesion. Therefore, the first patient received decompressive laminectomy of C3 and C4, removal of calcified round lesions, and posterior fixation from C3 to C5 due to associated kyphosis. The second patient underwent decompressive laminectomy of C3 and C4 and removal of calcified round lesions. Microscopic examination under polarized light showed dark blue calcifications with rhomboid crystals that were positively birefringent. The findings were consistent with those of CPPD. CONCLUSIONS: This is the first study to report cervical myelopathy caused by subaxial CPPD deposition with simultaneous asymptomatic CDS. Surgical removal of the subaxial CPPD deposition alone achieved a satisfactory surgical outcome without recurrence.