Biomechanical comparison of pullout strengths of five cortical screw types: An innovative measurement method.

OBJECTIVES: This study aims to assess five different cortical screw types using artificial femurs, under equated testing conditions. MATERIALS AND METHODS: We investigated the maximum force needed to cause deformation at screw-bone interface using fourth generation composite femurs by conducting separate pullout tests for each screw type. We normalized obtained results with traditional methods and cross-comparison. To conduct pullout tests dependent on screw dimensions, we eliminated the effect of bicortical bone thickness by equalizing the conditions of screw insertion. RESULTS: Non-locking screws with larger diameter and pitch depth required larger pullout forces to be extracted, showing statistically superior performance compared to locking screws with smaller dimensions. However, the statistical differences between the absolute pullout forces decreased after the traditional normalization of the results. We proposed a new normalization method based on solid geometric reasoning. CONCLUSION: This novel approach showed that a screw type that appeared to show average performance, in fact, did not have statistically significantly different results than the top performers. Surgeons are not required to prefer larger dimension screws in small dimension host bones.

The Mechanical Effect of Rod Contouring on Rod-Screw System Strength in Spine Fixation.

OBJECTIVE: Rod-screw fixation systems are widely used for spinal instrumentation. Although many biomechanical studies on rod-screw systems have been carried out, but the effects of rod contouring on the construct strength is still not very well defined in the literature. This work examines the mechanical impact of straight, 20° kyphotic, and 20° lordotic rod contouring on rod-screw fixation systems, by forming a corpectomy model. METHODS: The corpectomy groups were prepared using ultra-high molecular weight polyethylene samples. Non-destructive loads were applied during flexion/extension and torsion testing. Spine-loading conditions were simulated by load subjections of 100 N with a velocity of 5 mm min(-1), to ensure 8.4-Nm moment. For torsional loading, the corpectomy models were subjected to rotational displacement of 0.5° s(-1) to an end point of 5.0°, in a torsion testing machine. RESULTS: Under both flexion and extension loading conditions the stiffness values for the lordotic rod-screw system were the highest. Under torsional loading conditions, the lordotic rod-screw system exhibited the highest torsional rigidity. CONCLUSION: We concluded that the lordotic rod-screw system was the most rigid among the systems tested and the risk of rod and screw failure is much higher in the kyphotic rod-screw systems. Further biomechanical studies should be attempted to compare between different rod kyphotic angles to minimize the kyphotic rod failure rate and to offer a more stable and rigid rod-screw construct models for surgical application in the kyphotic vertebrae.

Automated personnel-assets-consumables-drug tracking in ambulance services for more effective and efficient medical emergency interventions.

Patient delivery time is no longer considered as the only critical factor, in ambulatory services. Presently, five clinical performance indicators are used to decide patient satisfaction. Unfortunately, the emergency ambulance services in rapidly growing metropolitan areas do not meet current satisfaction expectations; because of human errors in the management of the objects onboard the ambulances. But, human involvement in the information management of emergency interventions can be reduced by electronic tracking of personnel, assets, consumables and drugs (PACD) carried in the ambulances. Electronic tracking needs the support of automation software, which should be integrated to the overall hospital information system. Our work presents a complete solution based on a centralized database supported by radio frequency identification (RFID) and bluetooth low energy (BLE) identification and tracking technologies. Each object in an ambulance is identified and tracked by the best suited technology. The automated identification and tracking reduces manual paper documentation and frees the personnel to better focus on medical activities. The presence and amounts of the PACD are automatically monitored, warning about their depletion, non-presence or maintenance dates. The computerized two way hospital-ambulance communication link provides information sharing and instantaneous feedback for better and faster diagnosis decisions. A fully implemented system is presented, with detailed hardware and software descriptions. The benefits and the clinical outcomes of the proposed system are discussed, which lead to improved personnel efficiency and more effective interventions.

Cryptographically supported NFC tags in medication for better inpatient safety.

Reliable sources report that errors in drug administration are increasing the number of harmed or killed inpatients, during healthcare. This development is in contradiction to patient safety norms. A correctly designed hospital-wide ubiquitous system, using advanced inpatient identification and matching techniques, should provide correct medicine and dosage at the right time. Researchers are still making grouping proof protocol proposals based on the EPC Global Class 1 Generation 2 ver. 1.2 standard tags, for drug administration. Analyses show that such protocols make medication unsecure and hence fail to guarantee inpatient safety. Thus, the original goal of patient safety still remains. In this paper, a very recent proposal (EKATE) upgraded by a cryptographic function is shown to fall short of expectations. Then, an alternative proposal IMS-NFC which uses a more suitable and newer technology; namely Near Field Communication (NFC), is described. The proposed protocol has the additional support of stronger security primitives and it is compliant to ISO communication and security standards. Unlike previous works, the proposal is a complete ubiquitous system that guarantees full patient safety; and it is based on off-the-shelf, new technology products available in every corner of the world. To prove the claims the performance, cost, security and scope of IMS-NFC are compared with previous proposals. Evaluation shows that the proposed system has stronger security, increased patient safety and equal efficiency, at little extra cost.