Iatrogenic nerve injury during upper limb surgery (excluding the hand).

Nerve injury is the most feared complication of upper limb surgery. In about 17% of cases, the injury is iatrogenic and the potential for recovery is poor. In this context, patients file for compensation in about a quarter of cases. Defective patient installation or locoregional anaesthesia are rarely the cause of nerve injury. Nerves may be injured during creation of the surgical approach, implantation of the material or reduction of a traumatic injury. The injury is usually related to nerve release, retractor positioning or inappropriate limb-segment lengthening. Stretching and/or compression of a nerve trunk or branch is thus often the main cause. Among diagnostic tools, imaging studies (ultrasonography, computed tomography, and magnetic resonance imaging) provide information on nerve structure but not on the potential for recovery. Electromyography combined with a neurological examination establishes the diagnosis, guides the management strategy, allows nerve-function monitoring, and indicates when nerve repair or palliative surgery is indicated. Electromyography also has prognostic value, both at diagnosis and during follow-up, by showing whether nerve regeneration is taking place. When creating the surgical approaches, thorough familiarity with anatomic safe zones and nerve trajectories is crucial to ensure full control of the zones at highest risk for nerve injury. LEVEL OF EVIDENCE: IV.