Kümmell\'s disease

Clinical History

An 81-year-old woman presented with a history of osteoporosis, back pain and several minor falls. She came to the emergency room with diffuse abdominal pain.
Lumbar plain film and abdominal CT were performed, revealing a T12 fracture.
Four months later the patient came again because of worsening back pain. MRI was performed.

Imaging Findings

Lumbar plain film and abdominal CT revealed a T12 horizontal fracture. Note the radiolucent line due to the presence of intravertebral gas (Fig. 1, 2).
MRI (Fig. 3, 4) shows a collapse of T12 with two different areas. Posterior zone shows a fluid intravertebral collection (low signal intensity on T1- and high signal intensity on T2-weighted image). This is the so-called fluid sign. Anterior zone shows low signal intensity in all sequences due to intravertebral air (the vacuum cleft sign).

Discussion

Kümmel´s disease is an uncommon disease and was first described by Hermann Kümmell in 1891. It is a clinical condition in which patients develop a kyphosis months to years after a minor spinal trauma [1-7].

The incidence of the disease is underestimated because it is an uncommon pathology that may be mistaken for other entities and there are multiple synonymous terms that have been used to describe this pathology in the literature. However, it is estimated to have an incidence between 7-37% [6, 7].

This entity occurs in middle-aged and elderly patients (mean age 65.5 years and range 23–87 years) with a slight male predominance [7].
Risk factors include: osteoporosis, corticosteroid therapy, alcoholism, history of falls and radiation therapy.

The pathophysiology remains controversial, although the nonunion of the vertebral body due to ischaemia after compression fracture (avascular osteonecrosis) is the predominant hypothetical pathophysiology [3].

The affected vertebra are usually at the level of the thoracolumbar zone with the T12 segment being the most commonly affected.

Radiologic findings are [1-8]:
- Collapse of affected vertebra: Vertebral collapse was more advanced in those who have intravertebral gas compared to those who only had intravertebral fluid (Fig. 5).
- Vacuum cleft sign: A vacuum cleft due to accumulation of gas in the vertebral body can be seen in plain film, CT or MRI (hypointense in all sequences). It is highly suggestive of Kümmell's disease but not definitive because other studies have reported this finding in other conditions including malignancy.
- Fluid sign: The fluid sign has been described in cases of avascular necrosis of the vertebral body and occurs at the site of the fractured endplate, where compression forces are most severe. It is hypointense in T1- and hyperintense in T2-weighted images. This sign is highly suggestive of avascular necrosis.
- Double line sign [8]: An inner bright T2 line representing hypaeremic granulation tissue and an outer dark line representing the adjacent sclerotic bone.

Treatment of this disease includes conservative treatment, percutaneous treatments (kyphoplasty/vertebroplasty) or open surgery, and it must be individualized [3, 4].

Differential Diagnosis List

Final Diagnosis

Kümmell's disease

URL:	https://www.eurorad.org/case/12546
DOI:	10.1594/EURORAD/CASE.12546
ISSN:	1563-4086