What should be done if a metal fixation device for a two-level spinal fusion fractures with a 3mm break-off?

Management of Fractured Spinal Fixation Hardware in Two-Level Fusion

When a metal fixation device fractures with a 3mm break-off fragment in a two-level spinal fusion, surgical hardware removal and revision fixation is indicated if the patient is symptomatic with pain, neurological symptoms, or evidence of spinal instability. 1

Immediate Assessment Required

Clinical Evaluation

• Assess for symptomatic hardware failure: Progressive pain, decreased range of motion, tenderness over the hardware site, or neurological changes all indicate need for intervention 1
• Evaluate functional impairment: Inability to work or perform daily activities supports surgical intervention 1
• Document neurological status: Any new or progressive neurological deficits require urgent surgical consideration 2

Radiographic Assessment

• Obtain CT imaging: This is the gold standard to characterize the fracture, assess fragment position, and evaluate for hardware migration or dislodgment 1
• Plain radiographs: Serial films can document progressive hardware failure, including increased lucency around adjacent screws suggesting loosening 1
• Assess spinal stability: Look for progressive deformity, loss of alignment, or evidence of instability at the fusion site 2

Indications for Surgical Intervention

Hardware Explantation Criteria

Hardware removal is medically necessary when symptomatic rod, hook, or screw migration, dislodgment, or breakage occurs 1. The specific indications include:

• Symptomatic hardware failure with fractured fixation device 1
• Progressive pain at the hardware site that impacts quality of life 1
• Evidence of hardware migration or the 3mm break-off fragment causing symptoms 1
• Adjacent hardware compromise: Assess all instrumentation levels, as one hardware failure may indicate stress on adjacent levels 1

Surgical Planning Considerations

• Inpatient setting is appropriate for hardware removal in spinal fusion cases, particularly given the need for post-operative neurological monitoring 1
• Complex anatomy considerations: Two-level fusions with hardware failure may require assessment of the entire construct, not just the fractured component 1
• Concurrent hardware evaluation: All instrumentation should be assessed intraoperatively, as radiographic lucency around other screws may indicate impending failure 1

Revision Strategy

Biomechanical Principles

• Hardware alone eventually fails without fusion: Fixation devices are not designed to withstand prolonged stress indefinitely and will fail if solid bone fusion has not occurred 3, 4
• Assess fusion status: The critical question is whether the two-level fusion has achieved solid arthrodesis 2
• If fusion is incomplete: Revision fixation with re-instrumentation and bone grafting is necessary 3, 4
• If fusion is solid: Hardware removal alone may be sufficient if the bony fusion provides adequate stability 2

Surgical Approach Options

The Congress of Neurological Surgeons guidelines provide relevant principles for thoracolumbar instrumentation that apply to revision scenarios:

• Instrumentation without arthrodesis shows no difference in clinical outcomes compared to fusion in some contexts, but this applies to initial treatment, not revision of failed hardware 2
• Revision fixation considerations: If re-instrumentation is needed, both open and minimally invasive techniques can be considered based on the specific anatomy and surgeon experience 2
• Fusion is typically required in revision scenarios where the initial fusion has not achieved solid arthrodesis 3, 4

Critical Pitfalls to Avoid

Common Errors

• Ignoring adjacent level hardware: The 3mm fragment may be the obvious failure, but adjacent screws showing lucency on imaging may also require attention 1
• Underestimating instability: A fractured fixation device in a two-level fusion suggests either non-union or excessive stress on the construct 3, 4
• Delaying intervention in symptomatic patients: Progressive pain and functional impairment warrant timely surgical evaluation 1

Assessment of Fusion Status

• CT is essential: This determines whether solid fusion has occurred and guides the revision strategy 1
• Pseudarthrosis consideration: Hardware failure often indicates non-union, which requires revision fusion, not just hardware removal 3, 4

Non-Operative Management Contraindications

Non-operative management is not appropriate when:

• Symptomatic hardware failure is documented 1
• Progressive neurological deficits are present 2
• Spinal instability is evident on imaging 2
• The fractured fragment poses risk of migration or neurovascular injury 1

Post-Operative Considerations

If Hardware Removal Alone

• Only appropriate if solid fusion confirmed on CT imaging 2
• Close radiographic follow-up to ensure maintained alignment 2

If Revision Fixation Required

• Bone grafting typically necessary if initial fusion incomplete 3, 4
• Extended instrumentation may be needed if adjacent levels show stress changes 1
• Prophylactic antibiotics should be administered prior to incision 5