The Clinical Significance of Ossification of Ligamentum Nuchae in Simple Lateral Radiograph : A Correlation with Cervical Ossification of Posterior Longitudinal Ligament.

OBJECTIVE: Ossification of the ligamentum nuchae (OLN) is usually asymptomatic and incidentally observed in cervical lateral radiographs. Previous literatures reported the correlation between OLN and cervical spondylosis. The purpose of this study was to elucidate the clinical significance of OLN with relation to cervical ossification of posterior longitudinal ligament (OPLL). METHODS: We retrospectively compared the prevalence of OPLL in 105 patients with OLN and without OLN and compared the prevalence of OLN in 105 patients with OPLL and without OPLL. We also analyzed the relationship between the morphology of OLN and involved OPLL level. The OPLL level was classified as short (1-3) or long (4-6), and the morphologic subtype of OLN was categorized as round, rod, or segmented. RESULTS: The prevalence of OPLL was significantly higher in the patients with OLN (64.7%) than without OLN (16.1%) (p=0.0001). And the prevalence of OLN was also higher in the patients with OPLL (54.2%) than without OPLL (29.5%) (p=0.0002). In patients with round type OLN, 5 of 26 (19.2%) showed long level OPLL, while in patients with larger type (rod and segmented) OLN, 22 of 42 (52.3%) showed long level OPLL (p=0.01). CONCLUSION: There was significant relationship between OLN and OPLL prevalence. This correlation indicates that there might be common systemic causes as well as mechanical causes in the formation of OPLL and OLN. The incidentally detected OLN in cervical lateral radiograph, especially larger type, might be helpful to predict the possibility of cervical OPLL.

New Diagnostic Tool for Far Lateral Lumbar Disc Herniation : The Clinical Usefulness of 3-Tesla Magnetic Resonance Myelography Comparing with the Discography CT.

OBJECTIVE: To prospectively assess the diagnostic and clinical value of a new technique (3-tesla magnetic resonance myelography, 3T MRM) as compared to computed tomographic discography (disco-CT) in patients with far lateral disc herniation. METHODS: We evaluated 3T MRM and disco-CT of 25 patients, whom we suspected of suffering from far lateral disc herniation. Using an assessment scale, 4 observers examined independently both 3T MRM and disco-CT images. We analyzed observer agreement and the accentuation of each image. RESULTS: We found complete matching, and observer agreement, between high resolution images of 3T MRM and disco-CT for diagnosing far lateral disc herniation. CONCLUSION: We think noninvasive 3T MRM is an appropriate diagnostic tool for far lateral disc herniation as compared to disco-CT.

Posterior cervical fixation with a nitinol shape memory loop for primary surgical stabilization of atlantoaxial instability: a preliminary report.

OBJECTIVE: To evaluate a new posterior atlantoaxial fixation technique using a nitinol shape memory loop as a simple method that avoids the risk of vertebral artery or nerve injury. METHODS: We retrospectively evaluated 14 patients with atlantoaxial instability who had undergone posterior C1-2 fusion using a nitinol shape memory loop. The success of fusion was determined clinically and radiologically. We reviewed patients' neurologic outcomes, neck disability index (NDI), solid bone fusion on cervical spine films, changes in posterior atlantodental interval (PADI), and surgical complications. RESULTS: Solid bone fusion was documented radiologically in all cases, and PADI increased after surgery (p<0.05). All patients remained neurologically intact and showed improvement in NDI score (p<0.05). There were no surgical complications such as neural tissue or vertebral artery injury or instrument failure in the follow-up period. CONCLUSION: Posterior C1-2 fixation with a nitinol shape memory loop is a simple, less technically demanding method compared to the conventional technique and may avoid the instrument-related complications of posterior C1-2 screw and rod fixation. We introduce this technique as one of the treatment options for atlantoaxial instability.