Hiroshi Koshiyama1, Kenji Yamazaki. 1. Department of Cardiovascular Surgery, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku-ku, Tokyo, 162-8666, Japan, hkoshi.md@gmail.com.
Abstract
OBJECTIVE: Sternum external fixation with a sternal wire is widely used. However, it was inadequate fixation in the anterior-posterior and cranial-caudal directions. Using sternal pins can improve the stability. The utility of a small deviation was important with respect to sternal pain. Here, we evaluated the efficacy of a sternal pin in a small deviation in three directions. METHODS: Polyurethane foam was used. In the wire group, models were closed using two stainless steel wires. In the wire and sternal pin group, a hydroxyapatite/poly-L-lactide acid (HA/PLLA) sternal pin was used for internal fixation in addition to wire fixation. A sternal pin was inserted inside. Both sides were fixed with the testing machine and the shear stress was directed to one side. In each group, six models were tested for three directions. The relationship between the load and displacement of the model was measured at 1-mm displacement. RESULTS: In the anterior-posterior direction, the load value was 138.8 ± 8.3 (N) in the wire and sternal pin group and 51.6 ± 9.5 (N) in the wire group (p = 0.0003). In the cranial-caudal direction, the values were 148.0 ± 12.0 (N) and 83.1 ± 26.6 (N), respectively (p < 0.0001). In the lateral direction, these values were 273.2 ± 49.3 (N) and 266.9 ± 50.6 (N), respectively (p = 0.8323). CONCLUSIONS: Additional internal fixation using an HA/PLLA sternal pin significantly improved the stability of sternotomy closure in the anterior-posterior and cranial-caudal directions within a small deviation.
OBJECTIVE: Sternum external fixation with a sternal wire is widely used. However, it was inadequate fixation in the anterior-posterior and cranial-caudal directions. Using sternal pins can improve the stability. The utility of a small deviation was important with respect to sternal pain. Here, we evaluated the efficacy of a sternal pin in a small deviation in three directions. METHODS:Polyurethane foam was used. In the wire group, models were closed using two stainless steel wires. In the wire and sternal pin group, a hydroxyapatite/poly-L-lactide acid (HA/PLLA) sternal pin was used for internal fixation in addition to wire fixation. A sternal pin was inserted inside. Both sides were fixed with the testing machine and the shear stress was directed to one side. In each group, six models were tested for three directions. The relationship between the load and displacement of the model was measured at 1-mm displacement. RESULTS: In the anterior-posterior direction, the load value was 138.8 ± 8.3 (N) in the wire and sternal pin group and 51.6 ± 9.5 (N) in the wire group (p = 0.0003). In the cranial-caudal direction, the values were 148.0 ± 12.0 (N) and 83.1 ± 26.6 (N), respectively (p < 0.0001). In the lateral direction, these values were 273.2 ± 49.3 (N) and 266.9 ± 50.6 (N), respectively (p = 0.8323). CONCLUSIONS: Additional internal fixation using an HA/PLLA sternal pin significantly improved the stability of sternotomy closure in the anterior-posterior and cranial-caudal directions within a small deviation.