The safest method of sternal wire extraction post-midsternotomy closure

Background: An incident of fatal pericardial bleeding immediately after the extraction of a sternal wire prompted a search for the most appropriate method for removing sternotomy wire sutures. A model sternum was devised to explore this problem, and several commonly used techniques for wire extraction were evaluated. Methods: A wooden sternal model was constructed to simulate the dimensional properties of a sternum overlying the mediastinal cavity, and to imitate its tensile characteristics. A Monofil CrNi-316L (Johnson & Johnson, Brunswick, NJ, USA), No. 7 CCS, 9 metric, 4x45-cm wire was passed vertically through drilled holes. The suture was then crossed and pulled, thus joining the two boards and approximating the wire to their deep surface. A latex balloon filled with dye was placed inside under the boards. Wire holders were used to extract the wires, using a linear pulling technique and a coiling around the wire-holder tip technique. Sixty repetitions were performed for each method. Results: In 60 trials of direct linear wire pulling, balloon rupture occurred in 33 (55%), whereas tearing was noted only 15 times out of 60 attempts (25%) when the tense coiling method was used. Conclusions: Sternotomy wire sutures should be extracted using a controlled technique that ensures safety to vital tissues in close proximity to the sternal bone. The tense coiling procedure offers superior safety when compared to the direct pulling process, demonstrated by a lower incidence of balloon rupture because of the lesser degree of wire flexure. This technique has become the method of choice in our medical center.