Is early exploration of the radial nerve indicated in patients with radial nerve lesion and mid shaft humerus (midshaft humeral) fracture?

Early Exploration of Radial Nerve in Midshaft Humerus Fractures

Early radial nerve exploration is recommended for high-energy injuries and open fractures, but conservative management with observation is preferred for low-energy closed fractures with radial nerve palsy.

Management Algorithm Based on Injury Mechanism

High-Energy Injuries or Open Fractures: Early Exploration Indicated

Early surgical exploration (within 2 weeks) should be performed in the following scenarios:

• High-energy trauma with radial nerve palsy, regardless of fracture pattern 1, 2
• Open fractures of the humerus with associated radial nerve injury 1
• Spiral fractures with wedge fragments, which have high rates (29.1%) of nerve compression between fracture fragments 3
• Comminuted fractures with radial nerve dysfunction 3, 4
• Transverse fractures at the middle-distal humerus following high-energy trauma, as these carry higher risk of complete nerve transection 4

The rationale for early exploration in these cases is compelling: high-energy injuries have significantly higher rates of complete nerve transection requiring immediate repair 4, 2. In one study, 88.9% of explored nerves in high-energy injuries recovered completely, compared to only 55.6% recovery in non-explored cases 2.

Low-Energy Closed Fractures: Conservative Management Preferred

Observation without early exploration is recommended for:

• Low-energy closed fractures with radial nerve palsy 1, 5
• Simple falls or low-velocity mechanisms 5

Conservative management is supported by excellent spontaneous recovery rates: 95.8% of patients with low-energy injuries recover nerve function without surgical intervention 5. A systematic review found no significant difference in outcomes between early exploration and observation groups for low-energy injuries (OR 1.03,95% CI 0.61-1.72) 1.

Timing of Exploration

When exploration is indicated, it should be performed within 4-5 days on average (range 1-20 days), ideally within the first 2 weeks 3, 1. This allows for:

• Direct visualization of nerve status (compression vs. transection) 3
• Immediate repair if transection is identified 4
• Concurrent fracture fixation with open reduction and internal fixation 4

Intraoperative Findings to Anticipate

During exploration, surgeons commonly encounter:

• Nerve compression between fracture fragments (29.1% of cases, predominantly in spiral fractures) 3
• Macroscopically intact nerves (73% of explored cases) 4
• Complete nerve transection (27% of explored cases in high-energy trauma) 4

Critical Pitfall to Avoid

Do not delay exploration beyond 12 weeks in non-recovering cases. If conservative management is chosen initially, perform electrophysiological assessment at 12 weeks if no neurological recovery is evident 3. Delayed exploration beyond this timepoint may compromise outcomes, as nerve grafting becomes more complex with chronic injuries.

Risk Stratification Factors

High-risk features for complete nerve transection requiring immediate repair:

• Traffic accident mechanism 4
• Middle-distal shaft location 4, 2
• Displaced transverse or comminuted fractures with butterfly fragments 4
• High-energy mechanism (logistic regression shows injury mechanism is the most significant predictor) 2

The incidence of radial nerve palsy is substantially higher in high-energy injuries (24.8% of cases) compared to low-energy injuries (7.5%) 2.