Chance fracture

A Chance fracture is a type of vertebral fracture that results from excessive flexion of the spine.^[8][9] Symptoms may include abdominal bruising (seat belt sign), or less commonly paralysis of the legs.^[4][10] In around half of cases there is an associated abdominal injury such as a splenic rupture, small bowel injury, pancreatic injury, or mesenteric tear.^[3][5] Injury to the bowel may not be apparent on the first day.^[11]

Chance fracture
Other names	Chance fracture of the spine,[1] flexion distraction fracture,[2] lap seat belt fracture[3]
A Chance fracture of T10 and fracture of T9 due to a seatbelt during an MVC.
Specialty	Emergency medicine
Symptoms	Abdominal bruising, paralysis of the legs[4]
Complications	Splenic rupture, small bowel injury, mesenteric tear[3][5]
Risk factors	Head-on motor vehicle collision in which a person is only wearing a lap belt[2]
Diagnostic method	Medical imaging (X-ray, CT scan)[1]
Differential diagnosis	Compression fracture, burst fracture[6]
Treatment	Bracing, surgery[1]
Frequency	Rare[7]

The cause is classically a head-on motor vehicle collision in which the affected person is wearing only a lap belt.^[2] Being hit in the abdomen with an object like a tree or a fall may also result in this fracture pattern.^[12][10] It often involves disruption of all three columns of the vertebral body (anterior, middle, and posterior).^[7][6] The most common area affected is the lower thoracic and upper lumbar spine.^[6] A CT scan is recommended as part of the diagnostic work-up to detect any potential abdominal injuries.^[5] The fracture is often unstable.^[1]

Treatment may be conservative with the use of a brace or via surgery.^[1] The fracture is currently rare.^[7] It was first described by G. Q. Chance, a radiologist from Manchester, UK, in 1948.^[3][13] The fracture was more common in the 1950s and 1960s before shoulder harnesses became common.^[3][5]

Mechanism

In some Chance fractures there is a transverse break through the bony spinous process while in others there is a tear of the supraspinous ligament, ligamentum flavum, interspinous ligament, and posterior longitudinal ligament.^[10]

Diagnosis

A flexion-distraction fracture of T10 and fracture of T9 due to a seatbelt during an MVC.

On plain X-ray, a Chance fracture may be suspected if two spinous processes are excessively far apart.^[10]

A CT scan of the chest, abdomen, and pelvis is recommended as part of the diagnostic work-up to detect any potential abdominal injuries.^[5][10] MRI may also be useful.^[10] The fracture is often unstable.^[1]

History

It was first described by G. Q. Chance, an Irish radiologist in Manchester, UK, in 1948.^[3][13] The fracture was more common in the 1950s and 1960s before shoulder harnesses became common.^[3][5]