MDCT findings in Baastrup disease: disease or normal feature of the aging spine?

Baastrup disease is characterized by the development of abnormal contact between adjacent spinous processes. The clinical significance remains unresolved, a few studies showing Baastrup disease as a cause of back pain. The aim of this study was to establish the frequency of Baastrup disease in a large unselected cohort to determine whether it is part of the expected spectrum of degenerative changes in the aging spine.

The abdominopelvic CT scans of 1008 patients divided equally into seven age groups were retrospectively reviewed. Baastrup disease was judged present if there was close contact between adjacent spinous processes and if the apposing ends were sclerotic. The presence of other degenerative changes, such as disk degeneration, spondylolisthesis, and facet osteoarthritis, at affected levels also was noted.

Evidence of Baastrup disease was found in 413 patients (41.0%). A decade-on-decade increase in frequency was found with a peak of 81.3% among patients older than 80 years. As many as five levels were found to be affected in some patients (4.1% of 413), but in most patients (35.4%), one level was affected. Baastrup disease was most common at L4-L5. Associated degenerative changes were found at almost all affected levels (899/901).

Baastrup disease occurs with high frequency among the elderly. Our data show that it develops with increasing age and is part of the expected degenerative changes in the aging spine. Because of the nearly universal association with other degenerative changes, we urge caution before diagnosing Baastrup disease as the cause of back pain.