Assessment of the atlanto-occipital junction in the MRI of subjects with cervical disc herniation

Objectives: To demonstrate the normal limitsof Powers ratio and basion dens interval inpatients with disc herniations.Methods: The MRI of patients wereretrospectively evaluated by 2 radiologists.Four hundred and forty-five patients whowere admitted to Duzce University Hospitalwith neck pain without history of trauma werechosen between January 2004 and July 2006in this retrospective study. The patients werebetween the ages of 14-80 years.Results: Four groups were identified accordingto the number of disc herniations. Thenormal limits of Powers ratio and basion densinterval were 0.77±0.15 and 0.80±0.66 ingroup 0, 0.76±0.14 and 0.81±0.76 in groupone, 0.75±0.13 and 0.80±0.71 in group 2,0.76±0.14 and 0.81±0.74 in group 3, and0.77±0.16 and 0.81±0.66 in group 4. Therelationship between the number of discher niations and Powers ratio and basion densinterval was not statistically significant.Conclusions: Our results were in concordancewith the previous studies concerning thePowers ratio and basion dens interval.These 2 methods can be used in the MRI ofatlantooccipital dislocation suspected patientswith disc herniations.