Introduction
In today's challenging medical device market, the introduction of a new product is becoming increasingly difficult. Clinicians are looking for effective products that meet their needs and which are comprehensively supported by the company supplying them. Procurement teams in both the NHS and Private hospital groups have to balance the wishes of the clinicians with their responsibility to rationalise and standardise the range of products purchased.
Medical device manufacturers invest heavily in bringing new and innovative products to the market and in offering training and product support to users. In order for the needs of both the clinicians and the manufacturer to be met, it is vital that the process of launching a new product involves all stakeholders.
This article will examine the role of the customer in a typical medical device development process and will feature the development and recent launch of the Summit HiVac™ 7 bone cement mixing system as a case study to illustrate this discussion.
Understanding the Customer
Understanding the needs of the marketplace is a key starting point for the development of a new product and input from relevant stakeholders should be sought at this early stage. In the case of the HiVac™ 7 bone cement mixing device, consultations with Theatre Staff, Surgeons and Procurement personnel were critical in the formation of the Product Design Brief. With this product, initial focus groups were held with Theatre Nurses to gain feedback on their experiences of mixing bone cement and clinical practice. The focus groups consisted of scrub staff, some of whom currently used Summit mixing devices and some who used competitor systems. The discussions were centred on current techniques, the strengths and weaknesses of the mixing devices currently used and trends in surgical technique.
Focus groups can be invaluable in setting the requirements for a new product design, highlighting areas of concern to the users rather than the manufacturers. For example, with the HiVac™ 7 focus groups some significant limitations were highlighted with many of the bone cement mixing devices currently being used. In particular, reliability issues with devices where a mixing rod has to be snapped after mixing, the potential for unmixed powder to be generated in devices that are opaque and the physical effort required to use some devices, were amongst the identified problems. Simple to use designs were also favoured by the group as this has a significant influence on ease of use and the training requirement for a new product.
At this early stage of the development process surgeons were also interviewed with regard to their needs from a bone cement mixing & delivery device. Although theatre staff do the mixing, surgeons identified key requirements which were also added to the design brief. In particular, surgeons highlighted the need for good mix quality and a requirement for good feel and pressure generation from the cement delivery gun.
In many of today's medical device markets Procurement personnel are having an increasing role in deciding which medical devices are used by clinicians. With the HiVac™ 7 project, Procurement professionals were consulted and their needs added to the Product Design Brief. Cost effectiveness was highlighted as the key issue to this particular group. Discussions highlighted that the product price, the surgical benefits of the product, being able to buy a range of mixing devices from one supplier and training / product support were important elements in the cost effectiveness calculation.
Once all the stakeholders have been consulted, market share and projected return on investment calculated, the decision can then be made on how to progress with the Product Design Brief, based on the market research results.
Product Design & Development
The design and development of a new product is a dynamic process balancing innovative ideas and market feedback with practical issues such as manufacturing the product robustly and to a consistently high quality. The next phase of this process usually involves the creation of prototype product designs. Development engineers will use the Product Design Brief to guide the development of prototype devices. With the HiVac™ 7 product the intent was not only to produce a device that was as good as the other products in the market place but also to overcome the weaknesses that were apparent in some of these devices, as highlighted in the market research.
Once prototype designs are created they are converted into product models which should then be shown to clinicians. In the case of HiVac™ 7 a number of different design ideas were shown to nurses, surgeons and Procurement Personnel to guide the development programme. During this stage some ideas were rejected but others were highlighted as significant improvements over products currently being used.
For example, the HiVac™ 7 product is made from a transparent material. This allows clinicians to view the mix quality during mixing but is also strong enough to reliably resist the high levels of force that it would be subjected to during cement delivery. When shown to clinicians, this feature was viewed as being beneficial as clarity allows the user to maintain control over the mix and ensure consistent cement quality for the patient.
Whenever possible, it is useful to allow the various groups to use the prototype models. For example, to ensure that HiVac™ 7 was easy and simple to use, a number of different designs were evaluated by users. Different mixing handles, bases and paddle ideas were assessed to produce a final design that most Theatre Staff agreed was significantly easier to use than many existing products. Ease of use was highlighted as being a key element for new products as it gave confidence to those that operate the product, made training of new staff easier and should result in more consistent results for the patient.
Features to enhance product reliability should also be tested at this stage of the development programme. For example, positive feedback was given by users on the coloured snap point of the HiVac™ 7 mixing rod. This new idea was viewed by users as improving a significant area of weakness and product failure that occurs with a number of existing mixing devices.
Health & Safety related product features were also discussed at this stage. The HiVac™ 7 prototypes were of a closed design reducing the potential for users to be exposed to polymethylmethacrylate fumes during mixing. Even though all modern vacuum mixing systems reduce fumes to below Health & Safety guidelines 1 the closed system concept was well received by users.
Prototype designs were also shown to surgeons. Mix quality and cement strength were highlighted as being a key concern with this group. To enhance the mechanical properties of cement the HiVac™ 7 device was designed to operate at 550mmHg. The application of a vacuum during mixing reduces the air content in bone cement which up to a point makes the cement stronger and more likely to survive the extreme loading that it is subjected to post implantation. The vacuum level of 550mmHg was chosen due to previous test work 2 conducted by Queens University Belfast which demonstrates that this vacuum level is optimum. This paper demonstrates that the higher vacuum levels used by many existing mixing devices produce cement with very low levels of porosity leading to the cement suffering from excessive shrinkage. This has been shown to produce micro cracks in the cement mantle which can weaken the fatigue life of the cement. In addition excessive shrinkage has been shown to produce voids at the cement stem interface 3 which could increase the chance of aseptic loosening.
In addition to mix quality a number of surgeons were interested in the feel of the cement delivery gun and the pressure that it could generate during cement delivery. To enhance gun performance the HiVac™ 7 prototypes were designed with a narrow bore mixing & delivery tube. Surgeons suggested that this design feature would allow them to generate enough pressure in the cement delivered to the femur to create effective micro interlock which is important for secure fixation of the implant. In addition surgeons liked the lightweight manoeuvrable gun which contrasts favourably with the bulkier caged guns used with some existing mixing systems.
Prototype product designs were also discussed with Procurement personnel. This group of customers were keen to purchase all mixing devices from one company which helps to streamline the purchasing process. With this in mind a triple mix version of HiVac™ 7 was proposed which would cover the requirement for up to 120g of mixed cement for revision hip procedures. Although the demand for a triple mix was suggested to be modest, Procurement staff were keen to have this option to cover all surgical requirements.
Final Design Stage and Testing
Once feedback on prototypes has been gathered from all relevant stakeholders a final design is chosen. This design is fine tuned and tested by the development engineers to ensure that certain key criteria are met. Many of these criteria are regulatory requirements which have to be adhered to.
Functionality testing is critical to ensure that the product is going to perform as intended. For HiVac™ 7 this included destructive testing on components to ensure that the device is robust enough to function without failure. This also has to include the testing of components that have been sterilised as the sterilisation process can affect the strength of individual components. In addition, materials had to be tested to ensure that the components of the device were compatible with the aggressive characteristics of bone cement.
Mechanical testing of cement mixed in the new system was also an important step in the HiVac™ 7 project. The cement has to be tested to ensure that when delivered to the patient it is at least equal to the criteria set out in the international standard for bone cement ISO5833. In addition cement fatigue testing is conducted as this is viewed as a key performance indicator for long term cement survival. The importance of this was illustrated by the launch of the Boneloc bone cement in the early 1990's. This cement was sold on a number of key benefits and passed the basic ISO requirements. However later test work revealed that it suffered from poor fatigue properties 4. Had Boneloc been tested for fatigue failure prior to launch, the large amount of early implant failures 4 reported as a result of the Boneloc failure could have been avoided.
In addition packaging has to be assessed to ensure that during transit the sterility of the product is not compromised and that the product is not damaged. Also the product has to be aged tested to ensure that when launched the shelf life marked on the product is reliable.
During the final stages of initial product development the packaging design also needs to conform to the regulatory requirements of the markets that the product will be sold into. For example the information on the packaging for the HiVac™ 7 product had to be translated into 21 languages to reflect the regulatory requirements of those particular markets.
Once the product has passed all of its testing and conforms to the regulatory requirements of the market place it is ready for production. The launch stock of a new product faces rigorous Quality testing before being released, ready for sale.
Product Launch and Beyond
As part of a new product launch, detailed briefing and product training will need to be given to the relevant sales team. Product training needs to be comprehensive as new products often involve different techniques and methods which need to be fully understood before being passed on to users. In addition comprehensive product support programmes need to be in place to give users confidence and to ensure that the products are used correctly. In the case of the HiVac™ 7 the product support package included;
- In-service training programme
- Train the Trainer programme
- Principles of Bone Cement Mixing & Application educational programme
- Competency testing user assessment material
It is not enough for products to be sold and for the salesperson to walk away. Users now require comprehensive support especially during the early stages of adopting a new medical device.
The launch of a new medical device is not the end of the product development process. It is important that post launch feedback is gathered from users to indicate areas for future improvement. Many products evolve over time with minor changes helping to enhance the product offering. With the HiVac™ 7 product, as with all Summit Medical devices, a regular review of post market surveillance is conducted to ensure that products are performing as desired and to highlight areas for improvement where relevant.
The HiVac™ 7 example demonstrates the benefit of involving clinicians and Procurement staff in every stage of the product development process. Due to significant input from Theatre Staff, Surgeons and Procurement personnel the product has built on the strengths of existing bone cement mixing devices and has overcome some of the weaknesses.
In addition to customer feedback guiding the development of a new product it can also be used to help formulate the programme of activities that support the product once introduced. In the case of HiVac™ 7 this has resulted in a comprehensive support programme which is already a valued part of the HiVac™ 7 package. For a new medical device to survive in the long term it may need to evolve. Customer feedback is critical for this process to be successful and for the product to continue to meet the needs of the marketplace.
References
- Cary R, Morris L, Cocker J, Groves J and Ogunbiyi A, 1995. Methylmethacrylate Criteria document an occupational exposure limit: Health and Safety Executive.
- Dunne N J, Orr J F, Mushipe M T, Eveleigh R J, 2002. The relationship between porosity and fatigue characteristics of bone cement. Biomaterials 24 (2003) 238-245
- Bishop NE, Ferguson S and Tepic S, 1996. Porosity reduction in bone cement at the cement stem interface. J Bone Joint Surgery, 78B (3): 349-356
- Harper E.J, Bonfield W, 2000. Tensile characteristics of ten commercial acrylic bone cements. J Biomedical Material Research, V53, Issue 5:605-616
- Furnes O N, 2002, The Norwegian Arthroplasty Register 1987-2000
