AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Patients complaining of back pain following motor vehicle accidents or falls from significant heights should be considered to have spinal injuries until proven otherwise. With flexion-distraction mechanisms such as those observed in passengers restrained with lap seatbelts, a progression of injury from the posterior column of the thoracolumbar spine is observed anteriorly.¹ When this involves only the osseous structures, a Chance injury exists. First described in 1948, the Chance fracture represents a pure bony injury extending from posterior to anterior through the spinous process, pedicles, and vertebral body, respectively.² The Chance fracture most commonly is found in the upper lumbar spine, but it may be observed in the midlumbar region in children. The fracture occurs at a lower level in children because of their lower center of gravity.

The diagnosis is best made on good quality radiographs obtained in 2 planes (anteroposterior [AP] and lateral). Prompt recognition followed by appropriate reduction and immobilization usually results in a good clinical outcome. Associated intra-abdominal injuries are common,^{3, 4, 5} especially in the pediatric age group,^{6, 7} in which incidence approaches 50%. Thus, intra-abdominal trauma should always be excluded at the time of presentation.

Related Medscape topics:
Resource Center Trauma
CME Recommendation From USPSTF: Counseling About Proper Use of Motor Vehicle Occupant Restraints and Avoidance of Alcohol Use While Driving
Specialty Site Orthopaedics

Related eMedicine topics:
Lumbar Spine Fractures and Dislocations
Thoracic Spine Fractures and Dislocations
Lumbar Spine, Trauma
Abdominal Trauma, Blunt
Considerations in Pediatric Trauma

History of the Procedure

Surgery generally has not been used to treat this injury. Because Chance fracture is a pure bony lesion and reduction is readily obtainable with extension, closed management of this injury has been the treatment of choice.

Problem

Flexion-distraction forces are responsible for the Chance fracture, which is 1 of the 3 resulting injuries from this mechanism. Usually related to lap seatbelt use, this mechanism can result in complete ligamentous injury or a combination of bony, ligament, and disc involvement.¹

Unrecognized, Chance injuries may result in progressive kyphosis with ensuing pain and deformity. Associated intra-abdominal injuries can result in increased morbidity and mortality.

Frequency

Less than 10% of fractures involving the lumbar spine are a result of flexion-distraction forces. These injuries tend to occur between T12 and L4, with the highest incidence at L2.

Etiology

The most common history is that of a back-seat passenger restrained by a lap seatbelt and involved in a motor vehicle accident or that of a person who has fallen from a height.

Pathophysiology

The thoracolumbar spinal junction represents a transitional area from the rigid thoracic spine to the more mobile lumbar region. The thoracic spine's intrinsic stability is a result of the ribs and their articulation with the spine, the smaller disc spaces, and the frontal orientation of its facet joints. As the lower 2 thoracic vertebrae (T11-12) lose the anterior rib articulations (floating ribs), the facet joints also change orientation to become more oblique or sagittal, allowing an increase in mobility.⁸

Flexion-distraction forces are responsible for the Chance fracture. Usually related to lap seatbelt wear, this mechanism can result in complete ligamentous injury or a combination of bony, ligament, and disc involvement.

Clinical

The patient has back pain and, on clinical examination, may have a lap seatbelt abrasion across the abdomen. Be aware of the high incidence of associated intra-abdominal injuries, such as liver or spleen lacerations, bowel rupture, or pancreatic injury. Therefore, a thorough examination of the abdomen at the initial evaluation is of utmost importance.

It is wise to ask for a general surgical consultation at this time to ensure that an occult bowel or other viscus injury is not overlooked. While neurologic findings are uncommon with this injury, perform a thorough neurologic examination that includes motor, sensory, and reflex evaluation. Perform a rectal and bladder examination, including evaluation of the residual urine after the patient has voided. Palpation of the thoracolumbar spine is performed to assess points of maximum tenderness and palpable defects.

Radiographic assessment should begin with AP and lateral radiographs of the thoracolumbar spine. A demonstrable fracture line may be detected extending through the spinous process, pedicles, and vertebral body. In general, the diagnosis may be determined by plain films, but, occasionally, CT scans with frontal and sagittal reconstructions are beneficial.

Related eMedicine topics:
Initial Evaluation of the Trauma Patient
Lumbar Spine, Trauma
Abdominal Trauma, Blunt
Abdominal Vascular Injuries
Splenic Rupture

INDICATIONS

Section 3 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

While Chance fractures may generally be managed by closed reduction and immobilization in a thoracolumbosacral orthosis (TLSO) or hyperextension cast, surgery may be indicated for polytrauma patients or patients whose size makes closed treatment difficult or impractical.

RELEVANT ANATOMY

Section 4 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

The usual location for Chance fractures is at the thoracolumbar junction (T10-L2) in adults or midlumbar spine in the pediatric age group. The fracture lines are found to propagate from the spinous process posteriorly through the lamina, pedicles, and vertebral body anteriorly.

Conceptually, the thoracolumbar spine may be visualized as being composed of 3 columns, as described by Denis.⁹ The anterior column is represented by the anterior half of the vertebral body, disc, and anterior longitudinal ligament. The middle column consists of the posterior half of the vertebral body, its associated disc, and posterior longitudinal ligament. The posterior column includes the pedicles, facet joints, lamina, and spinous and transverse processes, as well as the ligamentous complex, including the ligamentum flavum.

Both the anterior and middle columns are primarily involved in resisting axial loading of the spine. The added importance of the middle column relates to its proximity to the spinal canal and neural elements. Displacement of the middle column can result in neurologic compression and deficits. The posterior column primarily resists tensile forces, such as those encountered in flexion-distraction injuries. In Chance fractures, the bony elements involved fail, with the ligamentous components remaining intact.

CONTRAINDICATIONS

Section 5 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Exogenous obesity may be a relative contraindication to the usual nonoperative management of Chance fractures because bracing may be difficult. In these instances, and in cases of multiple trauma, an operative approach may be indicated to stabilize these injuries.

WORKUP

Section 6 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Related eMedicine topics:
Initial Evaluation of the Trauma Patient
Lumbar Spine, Trauma
Abdominal Trauma, Blunt
Splenic Rupture

Lab Studies

• The laboratory workup, in general, is the same for any trauma patient. It should include a baseline CBC, urinalysis, and appropriate chemistry profile as indicated. Because of the high incidence of associated intra-abdominal pathology, pay close attention to liver function test results.

Imaging Studies

• Radiographs
• • The radiographic workup initially should include AP and lateral views of the thoracolumbar junction.
  • The posterior elements should be observed clearly to identify the fracture line and its propagation.
• Computed tomography may be necessary to clearly delineate the entire bony nature of this injury; sagittal and coronal reconstructions are helpful.¹⁰
• As a rule, MRI evaluation is not helpful except in the individual with unexplained neurologic deficits, which are uncommon with this injury. The scan may demonstrate a contusion of the conus or compression of the cauda equina, which may correlate with the clinical examination.¹¹

TREATMENT

Section 7 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

Medical therapy

Chance fractures can generally be reduced by placing the patient on a Risser table with hyperextension applied to the thoracolumbar junction. A fiberglass or plaster cast is then applied. Alternatively, a mold may be taken and a thoracolumbosacral orthosis made for stabilization. Patient selection is important to ensure compliance with orthosis use.

Once the flexion-distraction injury through the bony elements is approximated, and the kyphosis is reduced through extension of the thoracolumbar spine, the patient is maintained in the TLSO or hyperextension cast for 2-3 months. Following immobilization, obtain an upright lateral radiograph to assess any residual deformity. The union rate is high and the results are good with closed management.

A rehabilitation program consisting of extension exercises can be instituted, and most individuals return to work within 6 months. Residual backache may be a problem for the first year postinjury.

Surgical therapy

If immobilization is impractical (large body habitus) or the patient has polytrauma, surgical management may be indicated. A posterior approach to reconstruct the posterior tension band is preferred. This may be accomplished with either a rod-hook, hook-pedicle screw-rod, or pedicle screw-rod construct, depending on the individual patient's anatomy and the location of the injury. A similar operative approach may be used with ligamentous variants. Decompression usually is not a result of residual compression in this injury; realignment of the spine is of the utmost importance, followed by stabilization and arthrodesis.

Preoperative details

If operative intervention is selected, a computerized axial tomography scan detailing the pedicle anatomy is helpful in selecting the appropriate fixation device. If a neurologic injury is present, MRI may be helpful as well.

Intraoperative details

Because this injury involves a flexion-distraction mechanism, placing the patient on rolls providing an extension moment or on the Jackson table prone frame aids in the reduction of a Chance injury.

• In a midline approach to the thoracolumbar junction, a level above and a level below the affected area should be dissected. Once down to the tip of the spinous processes, subperiosteal dissection with Cobb elevators is carried out to the facet joints bilaterally. Further dissection around the facet joints to the transverse processes is performed to complete the exposure necessary for instrumentation.
• Surgical gauze for packing the lateral gutters is invaluable in assisting with hemostasis. At each level, troublesome bleeding can be encountered from segmental vessels around the facets and pars interarticularis.
• Instrumentation may involve as little as 1 level above and below the injured site, if pedicle screw fixation is possible. However, standard hook fixation may be used to incorporate 2 levels above to 1-2 levels below the zone of injury. A hybrid construct consisting of hooks above and pedicle screws below is also an option.
• Closure in layers is performed after a standard posterior lateral arthrodesis is performed. Complete meticulous decortication of the transverse processes, pars, and lateral aspect of the facet joints prior to application of autologous bone grafting.

Postoperative details

With optimal surgical fixation, early mobilization should be possible. The usual postoperative concerns of bowel and bladder function and advancing diet should be addressed carefully and individually. Deep vein thrombosis prophylaxis can usually be provided by compression hose and intermittent dynamic compressive devices, such as a foot pump or Venodyne boot. Use other means of anticoagulation on a case-by-case basis, taking care to weigh the risks versus benefits of such therapy.

Follow-up

Arthrodesis usually is complete by 6 months, if not sooner, in younger patients. A rehabilitation program can be instituted as healing progresses and should include a walking routine and back exercises for mobilization and strengthening.

Follow-up radiographs should be obtained at monthly intervals to ensure progressive healing and maintenance of spinal alignment.

COMPLICATIONS

Section 8 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

The most common complications are residual kyphosis and chronic mechanical back pain. Pressure sores under a cast can be avoided with proper padding and cast application and with frequent turning of the patient. Pressure sores can also be avoided by early mobilization.

Related Medscape topics:
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CME/CE Sciatica and Low Back Pain: Does Physical Therapy Provide Long-Term Benefits?

Related eMedicine topic:
Mechanical Low Back Pain

OUTCOME AND PROGNOSIS

Section 9 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

With proper recognition and early management, near-anatomic reduction and healing can be expected. After 3 months of immobilization in a cast or thoracolumbosacral orthosis (TLSO), a rehabilitation exercise program with emphasis on the extensor muscles of the thoracolumbar spine can assist the return to preinjury activity levels. The ultimate result may not be determined for a year postinjury, with long-term back pain being the major complaint.¹²

Related Medscape topics:
Resource Center Back Pain
CME/CE Sciatica and Low Back Pain: Does Physical Therapy Provide Long-Term Benefits?

Related eMedicine topic:
Mechanical Low Back Pain

FUTURE AND CONTROVERSIES

Section 10 of 11  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

With the advent of percutaneous and minimally invasive techniques for pedicle screw insertion, these devices may be applied more easily in multiple-trauma patients and others in whom closed management would be impractical.^{13, 14}

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• References

1. Eismont FJ. Flexion-Distraction Injuries of the Thoracic and Lumbar Spine. In: Levine A, Eismont FJ, Garfin S, Zigler J, eds. Spine Trauma. Philadelphia, Pa: WB Saunders; 1998:. 402-14.
2. Chance GQ. Note on a flexion fracture of the spine. Br J Radiol. 1948;21:452-3.
3. LeGay DA, Petrie DP, Alexander DI. Flexion-distraction injuries of the lumbar spine and associated abdominal trauma. J Trauma. Apr 1990;30(4):436-44. [Medline].
4. Triantafyllou SJ, Gertzbein SD. Flexion distraction injuries of the thoracolumbar spine: a review. Orthopedics. Mar 1992;15(3):357-64. [Medline].
5. Tyroch AH, McGuire EL, McLean SF, Kozar RA, Gates KA, Kaups KL, et al. The association between Chance fractures and intra-abdominal injuries revisited: a multicenter review. Am Surg. May 2005;71(5):434-8. [Medline].
6. Mulpuri K, Reilly CW, Perdios A, Tredwell SJ, Blair GK. The spectrum of abdominal injuries associated with Chance fractures in pediatric patients. Eur J Pediatr Surg. Oct 2007;17(5):322-7. [Medline].
7. Reid AB, Letts RM, Black GB. Pediatric Chance fractures: association with intra-abdominal injuries and seatbelt use. J Trauma. Apr 1990;30(4):384-91. [Medline].
8. Smith WS, Kaufer H. Patterns and mechanisms of lumbar injuries associated with lap seat belts. J Bone Joint Surg Am. Mar 1969;51(2):239-54. [Medline].
9. Denis F. The three column spine and its significance in the classification of acute thoracolumbar spinal injuries. Spine. Nov-Dec 1983;8(8):817-31. [Medline].
10. Bernstein MP, Mirvis SE, Shanmuganathan K. Chance-type fractures of the thoracolumbar spine: imaging analysis in 53 patients. AJR Am J Roentgenol. Oct 2006;187(4):859-68. [Medline].
11. Groves CJ, Cassar-Pullicino VN, Tins BJ, Tyrrell PN, McCall IW. Chance-type flexion-distraction injuries in the thoracolumbar spine: MR imaging characteristics. Radiology. Aug 2005;236(2):601-8. [Medline].
12. Mulpuri K, Jawadi A, Perdios A, Choit RL, Tredwell SJ, Reilly CW. Outcome analysis of Chance fractures of the skeletally immature spine. Spine. Nov 15 2007;32(24):E702-7. [Medline].
13. Beringer W, Potts E, Khairi S, Mobasser JP. Percutaneous pedicle screw instrumentation for temporary internal bracing of nondisplaced bony Chance fractures. J Spinal Disord Tech. May 2007;20(3):242-7. [Medline].
14. Schizas C, Kosmopoulos V. Percutaneous surgical treatment of Chance fractures using cannulated pedicle screws. Report of two cases. J Neurosurg Spine. Jul 2007;7(1):71-4. [Medline].

Article Last Updated: Jun 10, 2008