In 1958, the AO (Arbeitsgemeinschaft für Osteosynthesefragen) formulated four basic principles, which have become the guidelines for internal fixation : restoration of anatomical relationships, stable fixation, preservation of blood supply and early and safe mobilization. For more than half a century, steel wires were predominantly used to close the chest after cardiac surgery after median sternotomy. In between the profession has changed dramatically. Procedures and anesthesia are faster, less invasive, less harmful, and medication is more target-oriented. This results in a tremendous shift towards significantly older and sicker patients with comorbidities that limit survival and have crucial impact on wound and sternal healing.
Although a variety of different closure devices have been introduced in the past two decades, none has been able to fully replace wires in terms of practicability and costs. Sternal dehiscence, wound infections, mediastinitis, sternal fractures and non-unions are still unsolved problems that arise in 3-5%  of treated patients. Follow-up costs remain a considerable burden on health care systems [5, 6].
The ZipFixTM System is based on the cable-tie principle, which enables rigid fixation for use in primary sternal closure. The implantable device is exclusively made from PEEK, which has emerged as the leading high-performance thermoplastic material for many industries, including medical devices. By replacing some metal implant devices, PEEK has shown excellent stress resistance characteristics, biocompatibility and resistance in simulated “in vivo” degradation, including damage caused by lipid exposure .
Initial tests performed by Synthes demonstrated the superior fatigue strength of sternal ZipFixTM compared with stainless steel cerclage wires. Furthermore, due to the large implant to bone contact area, which results in an optimized stress distribution, the force to achieve bone-cut-through has to be significantly higher. A similar approach has been ventured by Sterna-BandTM. Compared with wires, these steel bands not only provided effective fixation, they demonstrated a reduction in postoperative pain and length of postoperative hospital stay [7, 8]. The advantages of the ZipFixTM over the Sterna-BandTM are the ease and speed of implantation and the reproducible tension of 200 N for each ZipFixTM. In case of an emergency, the ZipFixTM are easily cut by scissors. The “soft and smooth” material adapts perfectly to the bone. Additionally, the lack of sharp edges might be less vulnerable to the periostium. Thus, all four key principles formulated by the AO are respected in this device.
Concerning the costs of this new device they are, at the moment being, about 5 to 8 times more expensive than the conventional wires and though cannot be ignored. But as all new devices, prices will tend to be reduced as the use increases. In addition if stability can be improved even in extreme situation such as mechanical reanimation, some extra cost of reoperation for sternal refixation could be avoided. This cost effectiveness must now be examined.
Having implanted the first ZipFixTM worldwide, we present our short-term results in the inital 50 patients. None of them experienced sternal instability, including the two with mediastinitis and the other two female patients after successful external cardiac resuscitation. Since we decided to test this new CE certified product in our daily practice we did not conduct a randomized trial for our first clinical experience which is definitely a limitation to our study and this question has to be answered by newly conducted randomized controlled trials in the near future with special attention on health care costs.