• Acute L2 Chance-type fracture.

Chance Fracture.

A flexion-distraction injury of the lumbar spine.

It represents failure of both the posterior and middle spinal columns under tension forces generated by flexion and distraction (from a fulcrum focus anterior to the vertebral body).

• The anterior column may partially fail (under compression, acting as a hinge) or may completely disrupt (hinge failure).

This is an unstable fracture involving all three spinal columns.

There is significant distractive disruption of middle & posterior ligamentous structures (50% of cases).

• Typically interspinous ligament, ligamentum flavum, facet capsule, posterior annulus & thoracodorsal fascia are involved.
• The other 50% result from fracture through bone.

It is unusual, in that the fracture line extends through the spinous process, pedicle and into the vertebral body.

** Subtype of Flexion-Distraction Injuries – Image taken from Denis (1983) **

Most commonly associated with seat-belt injuries (especially isolated lap belts only).

• Also associated with pedestrian-vs-car injuries and falls.

This is often misdiagnosed as an anterior compression fracture.

Chance fractures are strongly associated with intraabdominal injuries. These result from rapid deceleration of intraabdominal contents against the lap belt, or compression against the anterior spine. There is also subsequent increased intraluminal pressure in hollow viscus structures.

• Associated intraabdominal injuries.
  • Small bowel
  • Spleen
  • Large bowel
  • Kidney
  • Pancreas
  • Omentum & mesentery
  • Liver
  • Stomach
  • Adrenal glands
  • Large vessel.

• Hollow viscus injury occurs in ~22% of Chance fractures.
  • However; in patients with identified intra-abdominal injuries, 65% have hollow viscus injury.

• Have high index of suspicion for more than one injury.

• Abdominal wall contusions (“seat-belt sign”) in combination with Chance fracture is very suggestive of intraabdominal pathology (50-68%) and increased need for laparotomy (50-72%).
  • The absence of abdominal wall contusions drops the likelihood of intraabdominal pathology and need for laparotomy to 14% & 9% respectively.

• Spinal cord injury may accompany up to 25% of Chance fractures.
  • Associated with high-grade posterior element dissociation.

• Abdominal aortic injuries (particularly dissection) have been known to occur in  paediatric trauma patients with Chance fractures.

CT scan is the preferred initial diagnostic modality of choice in the haemodynamically stable patient with a Chance fracture. It is however important to recognise its limitations particularly in the diagnosis of small bowel injury.

Remember to treat this injury like any other unstable spinal injury.

Our patient remained haemodynamically stable. Her MRI spine showed no evidence of epidural haematoma, canal or foramina narrowing. There was however ligamentous injury posteriorly, mainly at L1-2.

Whilst her mandible was repaired on Day 2, her splenic injury was managed conservatively.

This was her final operative repair prior to discharge home….

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2. Current Diagnosis & Treatment: Surgery, 13th Edition.
3. Wheeless’ Textbook of Orthopaedics.
4. Denis, F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine 8(8), 817–831.
5. Tyroch, AH et al. The association between Chance fractures and intra-abdominal injuries revisited: a multicenter review. The American surgeon, 71(5), 434–438.
6. Chapman JR et al. Thoracolumbar Flexion-Distraction Injuries: Associated Morbidity and Neurological Outcomes. Spine (Phila Pa 1976). 2008 Mar 15;33(6):648-57.
7. Inaba K et al. Blunt abdominal aortic trauma in association with thoracolumbar spine fractures. Injury. 2001 Apr;32(3):201-7.
8. Choit RL et al. Abdominal aortic injuries associated with Chance fractures in pediatric patients. J Pediatr Surg. 2006 Jun;41(6):1184-90.