Innovating in the medical device industry - challenges & opportunities ESB 2015 translational research symposium.

The European Society for Biomaterials 2015 Translational Research Symposium focused on 'Innovating in the Medical Device Industry - Challenges & Opportunities' from different perspectives, i.e., from a non-profit research organisation to a syndicate of small and medium-sized companies and large companies. Lecturers from regulatory consultants, industry and research institutions described the innovation process and regulatory processes (e.g., 510K, PMA, combination product) towards market approval. The aim of the present article is to summarise and explain the main statements made during the symposium, in terms of challenges and opportunities for medical device industries, in a constantly changing customer and regulatory environment.

Progressing innovation in biomaterials. From the bench to the bed of patients.

A Translational Research Symposium was organized at the 2014 annual meeting of the European society for biomaterials. This brought together leading Tier one companies in clinical biomaterials and medical device markets, small and medium enterprises and entrepreneurial academics who shared their experiences on taking biomaterials technologies to commercial endpoints, in the clinics. The symposium focused on "Progressing Innovation in Biomaterials. From the Bench to the Bed of Patients". The aim of the present document is to illustrate the content of the symposium and to highlight the key lessons from selected lectures.

Finite element analysis of intramedullary devices: the effect of the gap between the implant and the bone.

This paper examines the interaction interface between the implant and the bone for an intramedullary femoral nailing system using a finite element (FE) model and specifically considers the hypothesis that the local geometry at the interface is significant to the resulting localized contact stress between the medial and lateral aspect of nail and endosteum. Contact mechanics algorithms are used in the FE modelling technique that can be developed to deal with any form of intramedullary device for which contact at the bone-implant interface is important. Global stiffness data from the FE model are compared with available data from an experiment carried out on a construct of the bone and the device that uses intramedullary femoral nails. Acceptable agreement is obtained. The results demonstrate that the mechanical interface between the implant and the bone is significantly affected by the gap geometry and magnitude. In particular, larger gaps lead to greater concentrations of stress on the medial side, while the distribution of stress is more uniform at the lateral contacts. Furthermore, the results show that the gap can have a marked effect on the stresses that occur on the fracture plane.

Variability of the pullout strength of cancellous bone screws with cement augmentation.

BACKGROUND: Orthopaedic surgeons often face clinical situations where improved screw holding power in cancellous bone is needed. Injectable calcium phosphate cements are one option to enhance fixation. METHODS: Paired screw pullout tests were undertaken in which human cadaver bone was augmented with calcium phosphate cement. A finite element model was used to investigate sensitivity to screw positional placement. FINDINGS: Statistical analysis of the data concluded that the pullout strength was generally increased by cement augmentation in the in vitro human cadaver tests. However, when comparing the individual paired samples there were surprising results with lower strength than anticipated after augmentation, in apparent contradiction to the generally expected conclusion. Investigation using the finite element model showed that these strength reductions could be accounted for by small screw positional changes. A change of 0.5mm might result in predicted pullout force changes of up to 28%. INTERPRETATION: Small changes in screw position might lead to significant changes in pullout strength sufficient to explain the lower than expected individual pullout values in augmented cancellous bone. Consequently whilst the addition of cement at a position of low strength would increase the pullout strength at that point, it might not reach the pullout strength of the un-augmented paired test site. However, the overall effect of cement augmentation produces a significant improvement at whatever point in the bone the screw is placed. The use of polymeric bone-substitute materials for tests may not reveal the natural variation encountered in tests using real bone structures.

Ankle joint biomechanics.

A three-dimensional analysis of the human ankle joint is presented to analyse data obtained from gait laboratory tests. The ankle was treated as consisting of two joints, the talocrural (Tc.) and the talocalcaneonavicular (Tcn.), and relevant anatomical dimensions were based upon cadaveric anthropometric data. Seven adult male subjects were studied during the stance phase of normal locomotion. Data was acquired from three orthogonally placed cine cameras and a force platform. Two models were investigated based on force equilibrium; a Mark I model which excluded the posterior tibial and peroneal muscle groups and a Mark II model, which included them. The Mark II model gave the following resultant peak forces expressed as multiples of body weight; Tc. joint force = 3.9; Tcn. joint forces--anterior facet = 2.4, posterior facet = 2.8. The latter model was felt to have good potential in the analytical assessment of ankle pathologies and endoprostheses.

Intramedullary nails: some design features of the distal end.

Intramedullary nails are used to stabilise fractures of the proximal femur. The nail acts by transferring loads from the proximal fraction to the rest of the femoral shaft. The way in which this occurs depends to a large extent on the design of the distal end of the nail. This is not dissimilar to the situation with regard to load shedding (or load transfer) from the femoral component of a total hip replacement. A finite element model of a fractured femur with either a neck or a subtrochanteric fracture is set up to investigate the effects of nail length, nail distal stiffness and material stiffness on the structural behaviour of the system. Specifically what is considered is the influence of these parameters on the stress across the fracture and the normal pressure that the nail exerts on the endosteum of the femoral diaphysis. It is found that a longer nail could produce higher contact stress between the tip of the nail and the endosteum. Also, this contact stress is reduced when the distal region of the nail is made more flexible either by incorporating longitudinal slots or by using a material with a lower modulus of elasticity.

Intramedullary femoral nails: one or two lag screws? A preliminary study.

Failures of proximal femoral nails that treat unstable femoral fractures have been reported. In this communication, a finite element model to include a proximal femoral nail within a fractured femur was used to carry out preliminary investigations into configurations of single or double lag screws. The effects of the different types of fracture were investigated. The results show that in order to share the load evenly between two lag screws, a good configuration seems to be to have a slightly larger screw above the lower screw. This also ameliorates stresses in the nail at the lag screw insertion holes. However, using two screws in this way can lead to large stresses in the cancellous bone in the femoral head, and these stresses may be significant in the initiation of cut-out.

Finite element analysis of a Gamma nail within a fractured femur.

Failures of Gamma nails which treat unstable femoral fractures have been reported. In this paper, a finite element model to include a Gamma nail within a fractured femur was used to investigate the stresses in the Gamma nail. The effects for different types of fracture were investigated. The results show that its use for subtrochanteric fractures will cause higher stresses at the lag screw and upper distal screw insertion holes in the nail than when used for femur neck fractures.

Intramedullary nails with two lag screws.

OBJECTIVE: To investigate the structural integrity of intramedullary nails with two lag screws, and to give guidance to orthopaedic surgeons in the choice of appropriate devices. DESIGN: Alternative designs of the construct are considered, and the use of a slotted upper lag screw insertion hole is analysed. BACKGROUND: Intramedullary fixation devices with a single lag screw have been known to fail at the lag screw insertion hole. Using two lag screws is considered. It has also been proposed to use a slot in the nail for the upper lag screw to prevent the upper lag screw from sticking. METHODS: Bending and torsion load cases are analysed using finite element method. Consideration of both load conditions is essential. RESULTS: The results present the overall stiffness of the assembly, the load sharing between lag screws, and the possibility for cut-out to occur. CONCLUSIONS: While the slot for the upper lag screw might be advantageous with regard to the stresses in the lag screws, it could be detrimental for cut-out occurring adjacent to the lag screws. RELEVANCE: Comparative analyses demonstrate that two lag screws may be advantageous in patients whose cancellous bone quality is good and who impose large loads on the lag screw/nail interface. However, the use of two screws might pre-dispose to failure by cut-out of the lag screws. The addition of a slotted hole for the upper lag screw appears to do nothing significant to reduce the risk of such a failure.

The role of nurse education in the integration of information in the health care environment.

The central theme of the paper is to explore the issues surrounding the development of European-wide knowledgeable nurse practitioners for effective and efficient patient care in an information intensive health care environment. Examination will be made of the role education needs to play to complement the new paradigm of health care. Where practicable, comparisons will be made between nurses' and other health care disciplines' approach to the introduction of information systems and how 'shared' approaches could be beneficial to all professions and the patients in care. The paper will conclude with a vision for the future and consideration will be given to where European nurses should position themselves to remain accountable and autonomous practitioners in health care.

The mixed media tutorial: practical guide.

There has been growing interest in the use of video communications in education. This paper will describe how video communications can be used as part of a teaching and learning process linked with other communications technologies to give the student greatest advantage for effective learning to take place. The paper will conclude with a personal view of the teacher preparation required to realise appropriate use of mixed media.

A unified model to support an information intensive health care environment.

The two parts of this paper respectively analyses the mismatch between current systems and practice in health care, and present an outline design for enhanced Integrated Care Pathways (ICP) knowledge and information management based upon mature ICT technologies.

Intelligent systems for nursing education.

Health care is one of the fastest growing areas in terms of care, treatment and the exploitation of new technology in Slovenia. There is a great need for new approaches ensuring that education and work of health care professionals will be built upon the state of the art in nursing. As a consequence the educational, governmental and "industrial" institutions from Slovenia, UK, Italy and Greece have determined to work on above problem. EU agreed to support the project under the Phare Tempus Framework and the aim of this paper is to present an educational approach based on intelligent systems and its application in nursing education.

An approximate model for cancellous bone screw fixation.

This paper presents a finite element (FE) model to identify parameters that affect the performance of an improved cancellous bone screw fixation technique, and hence potentially improve fracture treatment. In cancellous bone of low apparent density, it can be difficult to achieve adequate screw fixation and hence provide stable fracture fixation that enables bone healing. Data from predictive FE models indicate that cements can have a significant potential to improve screw holding power in cancellous bone. These FE models are used to demonstrate the key parameters that determine pull-out strength in a variety of screw, bone and cement set-ups, and to compare the effectiveness of different configurations. The paper concludes that significant advantages, up to an order of magnitude, in screw pull-out strength in cancellous bone might be gained by the appropriate use of a currently approved calcium phosphate cement.

Injectable calcium phosphate cement for augmentation around cancellous bone screws. In vivo biomechanical studies.

In lower cancellous apparent bone density, it can be difficult to achieve adequate screw fixation and hence stable fracture fixation. Different strategies have been proposed, one of them is through augmentation using calcium phosphate cement in the region at or close to the screw thread itself. To support the hypothesis of an improved screw fixation technique by augmentation of the bone surrounding the implanted screw, in vivo biomechanical and densitometric studies are performed on rabbit specimen where normal and simulated weak bone quality are considered. In particular, the evolution of screw stability till 12 weeks following the implantation is quantified. A statistical significance in the pull out force for augmented versus non-augmented screws was found for the shorter time periods tested of ≤ 5 days whilst the pull out force was found to increase with time for both augmented and non-augmented screws during the 12 week course of the study. The results of the study demonstrate that the use of an injectable calcium phosphate cement which sets in vivo can significantly improve screw pull out strength at and after implantation for normal and simulated weak bone quality.