Discussion
Postoperative hemorrhage in cardiac surgical patients have been associated with surgical team experience, effects of hemodilution, hypothermia, inadequate reversal of heparin, thrombocytopenia, impaired platelet function, deletion of coagulation factors, and fibrinolysis.1,6,10 However, RV laceration from a fractured sternal wire is rare. One other case by Gong et al discusses fatal bleeding due to sternal steel wire fracture. Similarly, the cause of sternal wire fracture was thought to be due to increased cough in this case.
There are different methods used for sternotomy closure including a series of wires or a figure-of-eight method. With all types of sternal closure, there is some movement of the sternal halves under physiological loads, but with regimented sternal precautions complications are minimal.4 The mechanism of sternal fracture is generally thought to be caused by patient movement, but a recent study in the Journal of Orthopedic Research performed a biomechanical evaluation on the role of cerclage wire failure. Sternal wires have a material yield or failure strength, which if surpassed leads to deformities of the material.2 If sternal wires are to remain the gold standard for sternotomy closure, new techniques and/or materials must be developed to ensure tensile strength is not surpassed.
Risk factors for sternal dehiscence include COPD, re-operative surgery, renal failure, diabetes, chronic steroid use, morbid obesity, concurrent infection and acquired or iatrogenic immunosuppression. Our patient had an existing diagnosis of COPD, which brings to question whether an alternative method should have been used as primary closure.
A one-year follow-up of the ZipFix (Johnson and Johnson, New Brunswick, NJ) trial showed greater clinical advantages with regards to pain and sternal dehiscence post-surgery by using sternal ZipFix compared to conventional steel wire closure.8 Recent studies suggest that rigid plate fixation may lead to reduced sternal complications in high risk patients, improved perioperative survival, decreased length of hospital stay, improved pain and activity management with improved osteosynthesis.3,7,11 While other innovative techniques of sternal closure have been discussed such as reinforced wires, sternal plating and cables; none of these methods have been found to be reliable techniques or cost efficient when compared to sternal wires.3,4