The effects of the occipito-axial angle on the development of subaxial lesion after occipitocervical fusion are discussed. Twenty-seven patients without rheumatoid arthritis who underwent occipitocervical fusion for irreducible atlantoaxial dislocation were reviewed with an average 4.1 year follow-up. No significant relationship was seen between the abnormal range of the occipito-axial angle, and development of subaxial subluxation was not apparent. The effects of mechanical stress after occipitocervical fusion on the subaxial region were not significant in patients without rheumatoid arthritis.
