A 28-year-old woman is admitted with a deep laceration over the lateral aspect of the mid-forearm sustained during a knife attack. On examination, she has loss of wrist and finger extension, weakness of supination, and sensory loss over the dorsal first web space. Vascular examination shows intact radial artery pulsation. What is the most appropriate next step in management?

Explanation

## Management of Acute Radial Nerve Laceration ### Clinical Context A deep laceration over the lateral mid-forearm with loss of wrist/finger extension and sensory loss in the dorsal first web space indicates **posterior interosseous nerve (PIN) and/or superficial radial nerve (SRN) injury**. The intact radial artery pulsation does not exclude nerve injury. ### Key Point: **In an open laceration with clear signs of radial nerve injury, the nerve is likely transected or severely damaged. Urgent surgical exploration and primary repair (if transection is confirmed) is the standard of care.** This is fundamentally different from closed fractures with neurapraxia. ### Why Urgent Exploration and Repair is Correct 1. **Open injuries with visible nerve damage** require immediate exploration to assess the extent of injury. 2. **Primary repair** (within hours to days of injury) has superior outcomes compared to delayed repair, especially for motor nerves. 3. **Optimal window for repair** is within 72 hours of injury; after this, nerve ends may retract and fibrosis makes identification difficult. 4. **Anatomical continuity** must be restored to maximize functional recovery; simple wound closure without nerve repair will result in permanent motor and sensory deficit. ### High-Yield: **Open nerve injuries require urgent surgical exploration and primary repair if transection is confirmed. Do NOT close the skin without addressing the nerve.** [cite:Seddon's Peripheral Nerve Injuries] ### Mnemonic: OPEN NERVE INJURY MANAGEMENT - **O**pen laceration with nerve signs → **Urgent exploration** - **P**rimary repair within 72 hours → **Best outcomes** - **E**xamine under magnification (loupe/microscope) - **N**erve ends should be debrided minimally and approximated ### Clinical Pearl: **Motor deficit (wrist drop, finger extension loss) is more reliable than sensory loss for diagnosing acute nerve injury.** The dorsal first web space sensory loss confirms radial nerve involvement (superficial branch). ### Contraindications to Primary Repair - Severely contaminated wounds requiring debridement - Vascular compromise (but this patient has intact radial artery) - Crush injuries with extensive nerve damage - Delay >72 hours (relative, not absolute) [cite:Seddon's Peripheral Nerve Injuries 2e]