A 32-year-old man presents to the emergency department 6 hours after a fall on his outstretched right arm. On examination, he has a mid-shaft humerus fracture confirmed on X-ray. He complains of weakness in wrist extension and finger extension, with sensory loss over the dorsal first web space. Radial nerve injury is suspected. What is the most appropriate immediate management?

Explanation

## Management of Radial Nerve Injury in Acute Fracture Context ### Clinical Presentation Recognition **Key Point:** The patient exhibits classic radial nerve injury signs: wrist drop (loss of wrist extension), finger extension weakness, and sensory loss in the dorsal first web space (radial nerve sensory territory). ### Timing and Nature of Injury In the setting of a **closed mid-shaft humerus fracture**, the radial nerve injury is most likely a **neuropraxia or axonotmesis** (stretch/contusion injury) rather than complete transection. Approximately 18% of mid-shaft humerus fractures are associated with radial nerve injury, and the majority recover spontaneously within 3–12 weeks. ### Management Algorithm ```mermaid flowchart TD A[Radial nerve injury + closed humerus fracture]:::outcome --> B{Complete transection suspected?}:::decision B -->|No clinical/imaging evidence| C[Immobilize fracture, observe clinically]:::action B -->|Yes: penetrating trauma or nerve gap on imaging| D[Surgical exploration]:::urgent C --> E[Serial clinical exams at 3-4 weeks]:::action E --> F{Any recovery signs?}:::decision F -->|Yes| G[Continue conservative management]:::action F -->|No| H[EMG/NCS at 3-4 weeks to confirm denervation]:::action H --> I[Consider surgical exploration if complete block]:::action ``` ### Rationale for Immediate Conservative Management **High-Yield:** The standard of care for **suspected neuropraxia/axonotmesis in closed fractures** is: 1. **Immobilize** the fracture (prevents further nerve trauma) 2. **Clinical observation** for 3 weeks (allows time for spontaneous recovery) 3. **Electrophysiological studies** (EMG/NCS) at 3–4 weeks if no clinical recovery Surgical exploration is reserved for: - Penetrating injuries with suspected transection - Complete loss of function with no recovery signs after 3–4 weeks + EMG confirmation of complete block - Intraoperative iatrogenic injury **Clinical Pearl:** Neuropraxia can recover within days to weeks without intervention. Axonotmesis recovery takes 6–12 weeks. Immediate surgery in a closed fracture is not indicated unless there is high suspicion of transection (which is rare in blunt trauma). ### Why Not Corticosteroids? There is **no robust evidence** for high-dose corticosteroids in peripheral nerve injuries from fractures. Unlike acute spinal cord injury, steroids are not standard of care for peripheral nerve neuropraxia. ### Why Not Immediate Surgical Exploration? Without imaging evidence of nerve transection or penetrating trauma, immediate surgery risks iatrogenic injury and delays fracture stabilization. Surgery is reserved for cases with no recovery after 3–4 weeks.