Ossification of the ligamentum flavum as a result of fluorosis causing myelopathy: report of two cases.
OBJECTIVE
Ossification of the ligamentum flavum (OLF) is increasingly being recognized as a cause of myeloradiculopathy. However, the cause of such OLF has been identified only occasionally. The purpose of this case report is to highlight one more cause of OLF causing myelopathy.


METHODS
Two middle-aged men residing in an area endemic for fluorosis presented with the insidious onset of myelopathy. Clinical examination revealed evidence of thoracic cord compression in both patients. Plain x-rays revealed markedly increased bone density characteristic of fluorosis. Magnetic resonance imaging revealed OLF in the lower thoracic region causing cord compression (at one level in the first patient and at three consecutive levels in the second patient). Plain x-rays of the forearm revealed ossification of the interosseous membrane, which is characteristic of fluorosis.


METHODS
Both patients underwent decompressive laminectomy with removal of the OLF. The laminae and ossified yellow ligaments formed one mass of bone, which was removed with rongeurs and drills. After surgery, the first patient demonstrated improvement in motor power, whereas the second patient did not demonstrate any change in neurological status.


CONCLUSIONS
Fluorosis should be entertained in the differential diagnosis of OLF, especially in patients from endemic areas. The magnetic resonance imaging appearance of the spine in such cases is characteristic. In properly selected cases of fluorotic myelopathy, surgery is indicated. However, the prognosis is guarded, and long-term follow-up of these patients is necessary given the nature of the underlying disease.
Muthukumar
Natarajan
N
Department of Neurosurgery, Madurai Medical College, Madurai, Tamil Nadu, India. prasan86@eth.net
D019299:Decompression, Surgical; D003937:Diagnosis, Differential; D005459:Fluorides / Q000009:adverse effects*; D005542:Forearm / Q000473:pathology; D006801:Humans; D007796:Laminectomy; D017843:Ligamentum Flavum / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology; D009999:Ossification, Heterotopic / Q000209:etiology / Q000473:pathology*; D013118:Spinal Cord Diseases / Q000209:etiology* / Q000473:pathology
D005459:Fluorides