The clinical success rate using these techniques is 96% at 6-month, 94% at 24-month. However, the technique is not distributed everywhere since it is performed by highly specialized interventional radiologists. The PT is performed under general, spinal or regional anesthesia. General anesthesia is used in most cases, especially in children. When the OO is located in close proximity to the skin, cartilage, vessels and nerves, severe complications may occur and additional procedures such as infusion of saline or injection of CO2 at the interface between the OO and the vulnerable structure are done. Also few anatomic locations are not accessible to a PT.