Mirena for a small cervix???

I had been on depo for a long time and I loved it! In November I had a cyst removed from my ovary and my dr wanted me off of the depo shot. He gave me Nuva-ring, long story short the Nuva ring did not fit as I have a very small cervix and uterus and it just kept falling out.  He recommended Mirena however said that he would have to put me under anesthesia to see if he could dilate my cervix enough to insert the Mirena. I declined as I just has surgery and really could not go through another procedure. I have been on Lo-Seasonique ever since. I have been having headaches every day with the Seasonique and I am now seriously considering the Mirena. Has anyone heard of Mirena insertion under anesthesia, and/ or insertion with a small cervix??