Ossification of the posterior longitudinal ligament in vitamin D-resistantrickets - Case report and review of the literature

Study Design. A case report of cervical myelopathy caused by ossification o f the posterior longitudinal ligament in a patient with vitamin D-resistant rickets is presented together with a review of literature. Objective. To report the diagnosis of ossification of the posterior longitu dinal ligament in a white woman with vitamin D-resistant rickets. Summary of Background Data. The association between ossification of the pos terior longitudinal ligament and untreated vitamin D-resistant rickets has been reported in Japan, but infrequently in white populations. In whites, o ssification of the posterior longitudinal ligament is closely associated wi th diffuse idiopathic skeletal hyperostosis. A clear association between os sification of the posterior longitudinal ligament and vitamin D-resistant r ickets in white populations has not yet been established. Methods. The medical record and imaging studies of a patient treated at the authors' institution for cervical myelopathy caused by ossification of the posterior longitudinal ligament in the setting of treated vitamin D-resist ant rickets were reviewed. A Medline search of the medical literature betwe en 1966-1999 was performed to identify pertinent studies and similar case r eports. Results. The occurrence of spinal stenosis in untreated adults with vitamin D-resistant rickets has been reported in all regions of the spine in Japan ese patients. The association between ossification of the posterior longitu dinal ligament and untreated vitamin D-resistant rickets was first reported in Japan, where ossification of the posterior longitudinal ligament is end emic. This association may be incidental, because reports on ossification o f the posterior longitudinal ligament in whites are not as frequent as in J apanese, reflecting the higher prevalence of this condition in Japan. Conclusion. Ossification of the posterior longitudinal ligament and ossific ation of the posterior longitudinal ligament associated with deranged calci um or phosphate metabolism may be different pathologic entities sharing a c ommon outcome. Adequate treatment of vitamin D-resistant rickets may not al ways prevent or reverse ossification of the posterior longitudinal ligament .