What is the management and treatment for a suspected chance fracture?

Management and Treatment of Suspected Chance Fracture

Suspected Chance fractures require immediate surgical stabilization with posterior instrumentation when unstable (types involving posterior ligamentous disruption or bony fracture patterns), while stable fractures may be managed conservatively with hyperextension casting. 1, 2

Initial Diagnostic Evaluation

• Obtain standard anteroposterior and lateral radiographs of the thoracolumbar spine to identify the characteristic horizontal fracture line extending through the vertebral body, pedicles, and posterior elements 3
• CT imaging is essential to fully characterize the fracture pattern, assess stability, and identify associated injuries that may not be apparent on plain films 1
• MRI should be obtained when ligamentous injury is suspected, particularly to evaluate for posterior ligamentous complex disruption and disc involvement, which significantly impacts treatment decisions 1, 2
• Screen for associated intra-abdominal injuries (present in up to 50% of cases), as the mechanism of flexion-distraction commonly causes bowel, mesenteric, or solid organ injuries requiring urgent surgical intervention 2, 4

Classification and Stability Assessment

The Chance fracture has four variants that determine stability and treatment approach 3:

• Type A (classic Chance): Horizontal fracture through bone only - potentially stable
• Type B: Fracture through disc with posterior ligamentous disruption - unstable, requires surgery 3
• Type C: Mixed bony and ligamentous injury - unstable, requires surgery 3
• Type D: Pure ligamentous disruption - highly unstable, requires surgery 3

Surgical Management (Unstable Fractures)

Posterior instrumented fusion is the definitive treatment for unstable Chance fractures, with modern minimally invasive techniques offering superior outcomes 1, 2:

• Percutaneous pedicle screw fixation one level above and below the fracture provides excellent stability with minimal soft tissue trauma and blood loss 1, 2
• For fractures through the disc, single-level fixation combined with minimally invasive anterior discectomy and fusion may be performed 1
• For bony Chance fractures, short-segment fixation (one level above and below) is typically sufficient 1
• Surgical advantages include: early mobilization, minimal operative blood loss, reduced postoperative pain, and lower complication rates compared to open procedures 1, 2
• Hardware removal at 9 months post-injury is typically performed after confirmed osseous union 2

Conservative Management (Stable Fractures)

• Hyperextension casting may be considered only for truly stable, purely bony fractures without posterior ligamentous disruption 3, 5
• Close radiographic monitoring is mandatory as progression of kyphotic deformity occurs in 26% of conservatively managed cases 5
• Average residual kyphosis is significantly higher with nonoperative treatment (20 degrees) compared to surgical treatment (3.5 degrees) 5

Critical Management Considerations

Neurological assessment is paramount, as 43% of pediatric patients present with neurological deficits, and unrestrained patients have a 42% risk of permanent neurological injury versus 10% in restrained patients 5:

• Document complete neurological examination at presentation and serially thereafter
• Surgical treatment provides 84% good clinical outcomes (no chronic pain or neurologic deficit) compared to 45% with conservative management 5
• Early surgical stabilization allows for better neurological recovery and prevents secondary injury from instability 5

Special Populations and Mechanisms

• Athletic injuries can produce Chance fractures through extreme hyperflexion mechanisms (e.g., rodeo athletes pinned during bucking), not just motor vehicle accidents 4
• Maintain high index of suspicion when hyperflexion mechanism is present, regardless of activity type 4
• Pediatric patients (average age 9 years) most commonly sustain injuries at L2-L3 levels and require aggressive treatment to prevent long-term disability 5

Postoperative Management

• Early mobilization is encouraged following surgical stabilization, typically within days of surgery 1, 2
• Serial radiographs should confirm maintenance of reduction and progression to fusion 1, 2
• Hardware removal at 9 months after confirmed fusion prevents long-term complications while maintaining stability 2

Common Pitfalls to Avoid

• Delayed diagnosis occurs frequently because the injury pattern is not recognized on initial radiographs - always obtain CT when mechanism suggests flexion-distraction injury 3
• Underestimating instability by relying on plain films alone - posterior ligamentous disruption requires MRI for detection 1
• Missing associated abdominal injuries - maintain high suspicion and perform appropriate abdominal imaging 2, 4
• Attempting conservative management of unstable patterns - this leads to progressive kyphosis and poor outcomes 5