[Hermann Kümmell (1852–1937), professor of surgery at the University of Hamburg, published Chirurgische Operationslehre]

= INTRAVERTEBRAL VACUUM PHENOMENON

= delayed posttraumatic collapse of vertebral body

Incidence:<1% (on X-ray), 12% (on CT); in 15–30% of osteoporotic fractures

Cause: ischemic necrosis weeks to months following acute fracture

Pathophysiology: compression fracture → subsequent partial distraction by paraspinal muscles in supine position → vertebral cavity / cleft → low pressure within cleft allows accumulation of gas (principally nitrogen) in the absence of bleeding = “ischemic vertebral collapse”

Age:>50 years

Location: thoracolumbar junction: T12 & L1

• collapsed vertebral body
• transverse linear / semilunar radiolucency located centrally within / adjacent to endplate
• gas collection increases with extension + traction, decreases with flexion
• contiguous intradiskal vacuum phenomenon (in 83%)
• gas may become replaced by fluid

N.B.: presence of gas virtually excludes tumoral + infectious etiology (rare exceptions: myeloma, E. coli, clostridia, TB, brucellosis, peptococcus, streptococcus, staphylococcus)