What is the best course of action for a patient with a history of lumbar spine surgical repair who now presents with a fracture of screws and new onset left toe numbness?

Immediate Revision Surgery is Indicated for Hardware Failure with New Neurological Symptoms

A patient with fractured lumbar pedicle screws and new-onset left toe numbness requires urgent surgical revision to prevent permanent neurological injury. The combination of hardware failure and new neurological deficit represents a surgical emergency that demands prompt intervention 1.

Immediate Diagnostic Workup

Obtain CT scan of the lumbar spine immediately to assess:

• Exact location and extent of screw fracture 2
• Position of fractured screw fragments relative to neural structures 1
• Integrity of remaining hardware 2
• Status of bony fusion (if fusion was performed) 3

Perform detailed neurological examination documenting:

• Specific toe(s) affected and dermatomal distribution 1
• Motor strength of foot dorsiflexion and plantarflexion 1
• Sensory deficits in L5 or S1 distribution 1
• Presence of radicular pain 1

MRI with and without contrast should follow CT if:

• Infection is suspected 2
• Soft tissue evaluation is needed to assess nerve root compression 2
• CT findings are equivocal regarding neural compromise 2

Mechanism and Urgency

Fractured pedicle screws indicate either:

• Pseudarthrosis (nonunion) causing repetitive stress on hardware, occurring in 20-24% of instrumented fusions 4
• Biomechanical failure from inadequate construct strength 4
• Infection causing bone weakening around screws 4

The new toe numbness suggests:

• Nerve root irritation from screw migration or fragment displacement 1
• Progressive instability at the fractured segment causing neural compression 5
• Potential for permanent neurological injury if not addressed urgently 5

Surgical Revision Strategy

Revision surgery should be performed within 24 hours based on evidence that early intervention (within 24 hours) significantly improves neurological outcomes in thoracolumbar spine injuries 5.

Intraoperative Monitoring Requirements

Electrophysiological monitoring is mandatory during revision surgery 1:

• Evoked EMG with stimulation threshold testing has 100% sensitivity and 94% specificity for detecting nerve root proximity 1
• Continuous spontaneous EMG monitoring detects real-time nerve root irritation during screw removal and replacement 1
• Somatosensory evoked potentials (SSEPs) provide additional spinal cord monitoring 1

Revision Technique

Remove all fractured hardware and assess fusion status 3, 4:

• If pseudarthrosis is present (found in 59% of cases with broken screws), revision fusion is required 4
• If solid fusion is confirmed, hardware removal alone may suffice 4

For revision instrumentation 1:

• Extend fixation by at least one level above and below the original construct to distribute stress 3
• Use larger diameter screws (if pedicle anatomy permits) for improved purchase 1
• Consider anterior column support if significant anterior column deficiency exists 1

Intraoperative screw placement verification 1:

• Screws with stimulation threshold >11 mA indicate proper pedicle placement (100% accuracy) 1
• Screws with threshold <7 mA indicate pedicle breach requiring repositioning 1
• Direct visualization and palpation of medial pedicle wall confirms integrity 1

Critical Pitfalls to Avoid

Do not delay surgery for "observation" - neurological symptoms with hardware failure represent progressive instability requiring immediate intervention 5. Patients operated within 24 hours have significantly better neurological recovery (p<0.01) 5.

Do not assume fusion is solid without direct visualization - 20.7% of patients with late-onset pain and hardware failure have pseudarthrosis despite radiographic appearance of fusion 4.

Do not underestimate thoracic screw revision complexity - percutaneous techniques show higher malposition rates in thoracic spine (14.6% penetration rate), making open revision with direct visualization preferable 6.

Do not ignore infection as a cause - obtain intraoperative cultures and consider holding antibiotics until cultures are obtained if infection is suspected 4.

Postoperative Management

Obtain immediate postoperative CT to verify:

• Correct screw positioning within pedicles 2
• No residual neural compression 2
• Adequate construct alignment 2

Document neurological status immediately postoperatively and at regular intervals to detect any deterioration requiring re-exploration 1.

Restrict weight-bearing initially if revision fusion was performed, unlike primary trauma cases where immediate weight-bearing is appropriate 1.

Expected Outcomes

With prompt surgical intervention, 71% of patients with neurological deficits improve by 1-3 Frankel grades 5. However, delayed treatment significantly worsens outcomes 5. Three patients (0.3%) in one series had residual neurological weakness despite screw removal, emphasizing the importance of early intervention 4.