Risk to Neurovascular Structures Using Posterolateral Percutaneous Ankle Screw Placement: A Cadaver Study

Abstract

Over the past 20 years, ankle arthrodesis with use of screw augmentation has become a popular technique to gain fusion of the arthritic ankle. The objective of this cadaver study was to identify the risks to local neurovascular structures using standard operative practices for percutaneous guide pin placement. Nine fresh frozen cadaver limbs were used. A guide pin from the Synthes (Paoli, PA) 7.3-mm cannulated set was placed percutaneously into the distal posterolateral leg with the ankle held in neutral position. A layered dissection was then performed from the skin to tibia. Neurovascular injury and distance of the guide pin from the sural and tibial nerves were noted. The guide pin did not touch the sural or tibial nerves in any specimens. With this technique, the mean distance of the pin from the sural nerve and tibial nerve at the closest point was 0.9 mm and 6.5 mm, respectively. In placement of a percutaneous screw, care should be taken to start the posterolateral guide pin placement more lateral or closer to the fibula at this level in the leg to avoid injury to the sural nerve. Additionally, the tibial nerve is potentially an at risk structure if percutaneous pin insertion crosses medial to the coronal plane midline. The use of percutaneous screw placement is safe and effective with minimal risk to local neurovascular structures if standard operative technique is followed.