To prevent charge problem and to enhance the resolution, samples were sputtered with a thin layer of gold using a Polaron G-5000 sputter coater. Representative micrographs were taken in a second electron imaging mode. Surface morphology of wire samples was examined with scanning electron microscopy (SEM, Hitachi model S-800, USA). 2.1 Scanning electron microscopy analysis Break ends and striking surface alterations were further examined using energy dispersive X-ray analysis (EDAX). Irregularities were assayed by scanning electron microscopy. Eight fractured and 12 non-fractured wires extracted from five patients (closure method: figure-of-eight or straight twisted two without and three with mediastinitis) with a mean implantation interval of 13.2±4.2 days (range 8–20 days) were studied and documented by stereomicroscopy. The extracted wires were ultrasonically cleaned in distilled water for 15 min and the adhesive fibrotic tissues were gently removed with fingers.
316L stainless steel suture wire has austentic structure with low carbon content (0.03% weight), and is predominantly iron (60–65%) alloyed with chromium (17–18%) and nickel (12–14%). 2 Materials and methodsģ16L stainless steel is the most commonly used suture wire material. Therefore, the aim of our study is to analyze the potential risk of wire fracture and to ensure a secure and rigid fixation of the sternum by improving the property of sternal wire materials. In spite of this finding, sternal wire still fractured after a routine surgical procedure. The strength applied on the sternal wire after wound closure was far below the ultimate tensile strength (UTS) of wire as studied by Losanoff et al. X-Ray examination of the sternum after sternotomy shows evidence of a ruptured suture wire, dehiscence of the sternum, malpositioning of the wire ligature, cutting-through of the fixation wire by the bone fracture, pseudoarthrosis and inflammation. ĭehiscence often occurs within the first 2 weeks postoperatively before significant bone healing. The most important factor in preventing sternal dehiscence and mediastinitis is a stable sternal approximation. Sternal instability, wound infection, osteomyelitis and dehiscence are related. Conclusions: The synergic effect of stress and poor wire quality could be the precursors of material failure for the sternal wire.įractured wire, Sternal dehiscence, Scanning electron microscopy 1 IntroductionĪlthough sternal separation, or dehiscence is a rare complication of median sternotomy, it results in a mortality rate between 10 and 40%. EDAX revealed aluminum oxide inclusion on the fractured surface. Results: All examined fractured wires showed the presence of severe transversal cracks and crevice corrosion.
Irregularities and fractured ends were assayed by scanning electron microscopy and energy dispersive X-ray analysis (EDXA). The extracted wires were cleaned and the fibrotic tissues were removed.
Methods: Eight fractured and 12 non-fractured wires extracted from five patients (closure method: figure-of-eight or straight twisted two without and three with mediastinitis) with mean implantation interval of 13.2±4.2 days (range 8–20 days) were studied by various techniques. Surface alterations and fractured ends of sternal wires were inspected and analyzed. Objective: To understand the potential fracture mechanism of sternal wires, we collected extracted stainless steel sternal wires from patients with sternal dehiscence following open-heart operations.