Shear fractures affecting the three columns at the thoracic spine are highly instable and require surgical stabilization to avoid neurological injury. Patients with Ankylosing Spondylitis (AS) are at risk to sustain this type of fracture even with minor trauma. We present the case of a 72 years old male with AS who suffered a shear fracture of the thoracic spine involving all three columns. The injury was overlooked and the patient did not receive any treatment for two months. Surprisingly the patient did not develop neurological injury although he maintained his daily activities without external support. We propose the concept of fourth column as a stabilizer frame in this particular case and the management aspects concerning diagnosis and therapeutic treatment are discussed.

Shear fractures affecting the three columns at the thoracic spine are highly instable and require surgical stabilization to avoid neurological injury. Patients with Ankylosing Spondylitis (AS) are at risk to sustain this type of fracture even with minor trauma. We present the case of a 72 years old male with AS who suffered a shear fracture of the thoracic spine involving all three columns. The injury was overlooked and the patient did not receive any treatment for two months. Surprisingly the patient did not develop neurological injury although he maintained his daily activities without external support. We propose the concept of fourth column as a stabilizer frame in this particular case and the management aspects concerning diagnosis and therapeutic treatment are discussed.