Imaging Peripheral Nerve Injuries of the Lower Extremities: What Surgeons Need to Know

Peripheral nerve injury is a common sequela of lower extremity trauma. Injuries to lower extremity nerves range from contusions and stretch injuries that will often resolve without interventions to traumatic disruptions requiring surgical procedures, including neurolysis, repair or even nerve grafting. While clinical examination and tools such as electromyography will often help to localize the site of injury, imaging is a critical tool in determining the extent and degree of nerve injury in the setting of trauma. Modalities such as ultrasound and radiography are often useful, but MRI is considered the primary imaging modality for assessing the extent and degree of nerve injury. Specialized techniques such as MR neurography tailored to the needs of individual patients can provide important and detailed information in support of clinical decision making and presurgical planning. In this paper, we will review the anatomy of peripheral nerves of the lower extremity, mechanisms of injury affecting nerves and provide guidance for the use of MRI correlated with validated classification systems in assessing injuries affecting the nerves of the lower extremities.