As a result of load lifting a 68-year-old woman developed acute pain in the lumbar region, in a buttock, posterolateral surface of her right thigh, external surface of the right shin and dorsal surface of foot. Objectively: weakness of the anterior tibial muscle, long extensor muscle of the right toes, short extensor muscle of the right toes. Low Achilles reflex on the right. Positive Lasegue's sign. What examination method would be most effective for specification of the diagnosis of L5 root discogenic compression?