Bone imaging and skeletal radiology in dysbaric osteonecrosis

Detection of dysbaric osteonecrosis in military divers using magnetic resonance imaging

This was a controlled cross-sectional study to investigate the prevalence of dysbaric osteonecrosis (DON) in military divers. MRI examinations of the large joints and adjacent bones were performed in a cross-sectional group of 32 highly experienced military divers and 28 non-divers matched for age and anthropometric data. Additional plain radiographs and follow-up controls were performed in all persons with signs certain or suspicious of DON. In two subject groups (one of divers and one of non-divers), lesions characteristic of DON were detected. From this controlled study, it may be concluded that MRI is a highly sensitive method to detect signs of osteonecrosis. It could be shown that the prevalence of bone lesions characteristic of osteonecrosis in highly experienced military divers is not higher than in non-diving subjects of comparable age. The outcome of this comparably small study group fits to the results of previous extensive studies performed with radiographs. The detected low incidence of DON in this collective may be due to the fact that military divers follow stricter selection criteria, decompression schemes and medical surveillance than commercial divers.

The pathogenesis of osteonecrosis and the relationships to corticosteroids

One of the challenging issues faced by allergists is a risk-benefit analysis on the use of corticosteroids. An uncommon, but serious complication of corticosteroids is the development of avascular necrosis (osteonecrosis). In this review we present the differential diagnosis and pathophysiology of osteonecrosis, with particular emphasis on steroids. Osteonecrosis of the femoral head is a common disorder that may be either naturally occurring or iatrogenic. With the exception of those cases labeled as idiopathic, the majority are the result of some insult to the vascular integrity of the affected hip. The reason for this disruption is manifold and can range from direct trauma to the more subtle or indirect compromise associated with fatty emboli or often an intravascular event such as that seen in sickle cell anemia. Although they are not totally understood, corticosteroids present a special problem because of susceptibility factors that may make some patients more likely to get osteonecrosis than others. The problem may be more complex, in that the association between corticosteroid use and osteonecrosis may be disease-dependent. In any case, any patient receiving long-term corticosteroids should be warned of this potentially debilitating complication.

Avascular necrosis of bone--a complication of aggressive therapy for acute lymphoblastic leukemia

The purpose of the present paper was to report cases of avascular necrosis of bone (AVNB) arising as a complication of chemotherapy for acute lymphoblastic leukemia (ALL). X-rays and 99mtechnicium-MDP bone scans were performed on patients with symptoms of bone pain, whereby five patients out of 850 patients were detected to have avascular necrosis of the femoral head. All had received aggressive chemotherapy with steroids. Two patients were still on therapy for the primary disease. In these patients further chemotherapy was continued without steroids. The median period from diagnosis of ALL to development of AVNB was 29 months. Three patients underwent corrective surgical procedures. To conclude, the data suggest that patients receiving combination chemotherapy, especially those with high cumulative doses, run a risk of developing AVNB. Awareness of this complication is important in order to have an early diagnosis so as to limit disability.