Thanks for the question. There is very little risk of adverse event when needling near distal arteries but we do want to consider where they are especially when the artery is more superficial. If you were to hit the artery you may notice a small bruise or slight hematoma. I think the patient also typically feels a little pinch and a little soreness in the area when you happen to hit an artery. The reality is when needling you are going to hit arteries at times.
The Sural nerve point you mentioned is a sensory n. to the posterior lower leg so you could choose to needle superficially if you felt inclined and still get a sensory response in the nerve distribution. You have to consider that you have a deep artery inside a flexible sheath and getting a thin, flexible needle to penetrate the artery may be difficult as long as you are not using aggressive needle manipulation techniques. Piercing an artery is more likely where the artery ( and in the case the tibial nerve) would be more superficial especially directly midline in the posterior knee and at HA point for the tibial nerve above medial malleolus. So we do typically recommend being cautious with needle manipulation and pistoning techniques in these areas. As always use needling techniques that allow you to adjust if the patient feels something sharp or nerve like. Hope that helps and let me know what follow up questions you have so we can clear it up for you! Nick