Kümmell's Disease: Clarifying the Mechanisms and Patients' Inclusion Criteria.

The three major causes of vertebral body collapse include infection, malignant neoplasia, and trauma and it may be difficult to distinguish between them, particularly in the presence of severe osteoporosis. In 1891, however, Dr Hermann Kummell, further added another possibility of vertebral body crush; the delayed posttraumatic collapse. As originally described, this rare clinical entity includes patients, who after a trivial trauma and an asymptomatic clinical course they develop a progressive vertebral body collapse and a painful kyphosis. Although more than a century has passed from its initial description, only few cases have been reported in the literature, whereas the main pathologic eliciting event is still under investigation. As a consequence, great controversy exists regarding the discrete features of the clinical course, its radiographic appearance and the histopathological findings. To explain the time lag between the initial trauma and the occurrence of the vertebral collapse, the hypothesis of ischemic necrosis was advanced. Equation of Kummell’s disease with vertebral osteonecrosis, however, has wrongly led many authors to report cases of Kummell’s disease, even in the absence of history of spinal trauma. On the other hand, high coincidence of vertebral osteonecrosis and the pathognomonic radiographic finding of intravertebral vacuum cleft, has further added to the confusion. In this review we present an overview of the literature on Kummell’s disease, focusing on the different proposed eliciting mechanisms. We also highlight controversial subjects on clinical course, diagnosis and treatment of this entity, in an attempt to further clarify patients’ inclusion criteria.