Femoral Nerve Injury After Prone-Position Lumbar Discectomy: A Case Report Highlighting the Role of Ultrasound in Recovery Monitoring

Postoperative peripheral nerve injuries are well-recognized complications of surgical positioning. In prone spinal surgeries, lateral femoral cutaneous nerve injuries are common, but femoral nerve injuries are rare. We present a case of femoral nerve injury following prone-position spinal surgery, highlighting the role of ultrasound imaging in diagnosis and management. A 79-year-old man developed anterior thigh pain, along with iliopsoas and quadriceps weakness, following lumbar discectomy at the L3/4 and L4/5 levels. Neurological evaluation revealed a positive Tinel-like sign over the rectus femoris near the inguinal ligament. Ultrasound showed no hematoma but suggested nerve traction or compression. Targeted rehabilitation significantly improved pain, muscle strength, and function within two weeks. Ultrasound imaging confirmed enhanced femoral nerve mobility, which correlated with symptom resolution. This case highlights the importance of distinguishing femoral nerve injuries from radiculopathy and demonstrates the utility of ultrasound for diagnosis and monitoring recovery. Although femoral nerve injuries in prone surgeries are uncommon, awareness and early rehabilitation are critical for favorable outcomes.