How should a sacral fracture be managed, including assessment of stability and neurologic involvement, and what are the appropriate conservative and surgical treatment options?

Sacral Fracture Management

Sacral fractures require immediate comprehensive neurological assessment using the ASIA Impairment Scale, with treatment decisions based on fracture stability, neurological involvement, and Denis classification zone—stable nondisplaced fractures are managed conservatively with early mobilization, while displaced fractures with neurological deficits require urgent surgical reduction and fixation. 1, 2, 3

Initial Assessment and Diagnosis

Neurological Examination Priority

• Perform complete ASIA Impairment Scale grading immediately, as entry ASIA grade is the strongest predictor of functional outcomes 4
• Specifically assess sacral sensation (perianal region), rectal tone, and voluntary anal/urethral sphincter contraction—these are critical prognostic indicators for recovery 4
• Test ankle spasticity, which is highly predictive of neurogenic bladder dysfunction in sacral fractures 4
• Evaluate abductor hallucis motor function bilaterally, as this specifically predicts neurological recovery in lumbosacral injuries 4
• Document lower extremity motor strength in all major muscle groups using 0-5 grading 4

Imaging Protocol

• CT scan is the diagnostic modality of choice for sacral fractures, as plain radiographs miss 35% of cases 4
• Obtain MRI when any neurological deficit exists or when nerve root compression needs evaluation, as MRI is superior for detecting neural compromise 4, 3
• MRI is mandatory before surgical decision-making in displaced fractures with neurological symptoms 3

Classification and Stability Assessment

Denis Classification System

• Zone I fractures (sacral ala, lateral to neural foramina): typically stable, rarely cause neurological deficits 1, 2, 5
• Zone II fractures (through neural foramina): moderate instability, higher risk of nerve root injury 1, 2, 5
• Zone III fractures (through central canal): highest instability and neurological risk, often associated with spinopelvic dissociation 1, 2, 5

Pelvic Ring Stability

• Assess for associated pelvic ring injuries, as sacral fractures commonly occur with anterior pelvic disruption in high-energy trauma 1, 2, 6
• Pelvic ring instability mandates surgical stabilization regardless of neurological status 5, 6

Treatment Algorithm

Conservative Management Indications

• Nondisplaced or minimally displaced fractures without neurological deficit 1, 2, 5
• Stable pelvic ring configuration 2, 5
• Treatment consists of: rest, aggressive pain control, and early mobilization as tolerated (not prolonged bed rest) 2, 6
• Conservative treatment permits satisfactory results in appropriately selected patients 5

Surgical Indications (Absolute)

• Cauda equina syndrome associated with sacral fracture—this is an absolute indication for urgent reduction and decompression "as early as possible" 3
• Significantly displaced fractures with pelvic ring instability 2, 5, 6
• Complete radicular neurological deficit with imaging showing nerve root compression 3
• Progressive or worsening neurological deficit regardless of initial severity 3
• Spinopelvic dissociation (Zone III fractures with vertical instability) 1, 6

Surgical Indications (Relative)

• Incomplete radicular deficit in low-energy trauma with imaging evidence of root compression may warrant decompression 3
• Incomplete radicular deficit in high-energy trauma does NOT routinely require laminectomy after reduction 3

Surgical Techniques

Reduction Approach

• Closed reduction through external maneuvers is NOT mandatory before proceeding to open decompression when indicated 3
• Transcondylar traction is NOT a valid method for sacral decompression 3
• Special patient positioning, manipulation techniques, and specific reduction tools improve fracture reduction 6

Fixation Options

• Percutaneous iliosacral screws: for minimally displaced Zone I-II fractures without significant instability 1, 2, 6
• Posterior sacral tension band fixation: for Zone II-III fractures requiring posterior stabilization 1, 2
• Lumbopelvic (triangular) fixation: for spinopelvic dissociation, Zone III fractures, or when sacral bone quality is poor 1, 2, 6
• Following sacral decompression, surgical fixation MUST be performed (e.g., sacroiliac screws, triangular osteosynthesis, or lumbopelvic fixation) 3
• Anterior pelvic fixation should be added when sacral fractures are associated with anterior pelvic ring injuries to increase stability and reduce posterior implant failure 6

Critical Pitfalls to Avoid

• Missing the diagnosis: maintain high clinical suspicion in polytrauma patients, as sacral fractures are frequently overlooked 1, 6
• Inadequate neurological examination: never assume neurologically intact status without formal ASIA examination, especially in obtunded patients 4
• Delayed imaging: do not rely on plain radiographs alone—obtain CT for all suspected sacral fractures 4
• Underestimating subtle findings: isolated ankle spasticity or sphincter dysfunction have major prognostic implications for bladder recovery 4
• Delayed decompression in cauda equina syndrome: timing is critical—"as early as possible" improves neurological outcomes 3

Prognosis and Expected Outcomes

• Patients with spinopelvic dissociation and neurological lesions rarely recover completely, with residual lower-limb deficits, urinary problems, and sexual dysfunction 6
• Sacral sensation preservation and voluntary sphincter contraction correlate with better bladder recovery potential 4
• Conservative treatment of stable fractures typically yields satisfactory results 5
• Surgical stabilization of unstable fractures with appropriate technique achieves good clinical results and functional outcomes 1