Functionally Stratified Design and Manufacturing of Orthopaedic Devices – November event outcomes
December 10, 2014
On Monday 17th November, University of Leeds hosted the third MeDe Innovation Outreach workshop.
Patient and surgical variations have major effects on the failure rates, patient satisfaction, pain scores and other quality of life outcomes of many musculoskeletal interventions. Matching the right patient to the right product at the right time remains a challenge in the way devices are designed and manufactured.
Through MeDe Innovation, a new approach is being undertaken to improve testing methods and implement functional stratification into the design and manufacture process.
The aim of this workshop was to explore recent advances in pre-clinical testing which capture the effects of patient and surgical variability and the development of new products encompassing stratified design and manufacture. The workshop was held at the University of Leeds and was attended by over 75 delegates.
Professor John Fisher (University of Leeds) who is Principal Investigator on the MeDe Innovation EPSRC Centre for Innovative Manufacturing in Medical Devices began the day with an introduction to the concept of ‘functionally stratified design and manufacture’. Professor Fisher explained how variables such as anatomy, material properties, surgical positioning and patient activities affect the outcome of a medical device and therefore need to be taken into account in the design and pre-clinical testing of the product. This would lead to improved product segmentation and targeted design solutions to reduce variability in function across the whole population.
Graham Isaac (Depuy Synthes) then explained why improved stratification is important from an industrial point of view. Using the example of hip replacement surgery, he explained how when first introduced in the 1960s, a single design of device was implanted by a single surgeon. Now there are many thousands of surgeons implanting a huge range of different models of replacement device, and the outcomes are much more variable. There is a need to produce stratified solutions for different patient populations and usages, and for the design and testing methods to reflect these variances.
Dr Suzanne Halliday (British Standards Institution) presented on regulation for stratified design. Dr Halliday explained the regulatory pathway and classification of different medical devices, the essential requirements and how these are considered across all phases of the device lifecycle. She then discussed the implications for stratified design, emphasising that regulation should not be a barrier to innovation.
Professor Gordon Blunn (University College London) and Dr Mazen Al-Hajjar (University of Leeds) presented aspects of current research related to the hip. Professor Blunn’s talk considered a number of aspects of replacement design, highlighting that stratification is not just related to patient age and that there is a need to consider younger patients and revision cases. Dr Al-Hajjar presented current research to extend preclinical simulator testing to represent more realistic conditions likely to cause extremes of wear seen clinically.
In the afternoon, Dr Donal McNally (University of Nottingham) chaired the first session on the spine. Professor Ruth Wilcox (University of Leeds) presented the need for stratified design in the spine, highlighting the failure of some current technologies which is linked, in part, to the range of anatomies seen in the patient population. Dr Sebastien Sikora (University of Leeds) then presented research being undertaken to represent the patient population in a virtual model using a new principal component analysis tool embedded within Simpleware software.
Dr Alan Parish (University of Nottingham) presented research from the University of Nottingham on developing a navigation tool to help surgeons orient pedicle screws more effectively using patient-specific models based on CT data. Finally, Dr Nicholas Dunne (Queen’s University Belfast) presented on research at Queen’s University Belfast to develop new calcium phosphate based cement for vertebroplasty with improved fracture toughness.
In the final session on the knee, Dr Louise Jennings (University of Leeds) provided an overview of functionally stratified design and manufacture, highlighting that current designs of knee replacement do not take account of global variation and are usually tested pre-clinically under single set of conditions. Dr Abdellatif Abdelgaied (University of Leeds) presented current research at the University of Leeds to incorporate the effect of kinematics and surgical positioning into pre-clinical testing to examine the effects of these variables on the wear of knee replacements.
The morning and afternoon sessions were followed by lively panel discussions with the speakers.
The day included interactive debates about the challenges of implementing stratified design and manufacture across different sectors. Key factors included:
• identification of robust methods for testing variables relating to difference in device efficacy
• identification of critical parameters to represent different groups
• defining tolerance levels within variables
• opportunities to translate from lab to clinic not being sufficient
• effect on price of stratified implants
• possible requirements for different diagnostics needed
• will manufacturers need to consider reimbursement based on the implant performance?
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