Where colour meets clarity
Clear medical devices are often essential to effective patient care. The transparency of plastic materials in applications such as cannulae, needles, and fluid bags allow healthcare professionals to visually inspect contents, make observations for foreign objects, and monitor for unexpected events, such as bleeding or the appearance of an infection. In addition, clear, colourless, and brightly tinted plastics are associated with a clean and sterile device, which also aids in patient comfort. Recently, more device applications have taken advantage of colour-coded clear plastics to help clinicians identify devices.

To ensure that a device reaches the healthcare setting with its intended colour and clarity, manufacturers must understand available sterilization methods and the effect each may have on the colour of the polymer used to develop the device. 

Importance of Color and Clarity 
Healthcare practitioners commonly rely on colour-coded medical devices for split-second identification. During critical medical emergencies and procedures, practitioners must be able to quickly, efficiently, and correctly identify and select medical devices based on colour, which can indicate the size, type, and function of the device. Such easy identification and quick execution can help reduce medical errors and save time. For example, emergency room nurses often report that colour coding helps them find the correct devices quickly, thus reducing the risk of an error. Color-coded devices help provide timely and lifesaving care because healthcare professionals don’t have to question whether they have the right equipment. Colour coding also helps surgeons distinguish between different devices and tools. 

 For example, Smith & Nephew Endoscopy, a manufacturer of arthroscopic devices, developed its Clear-Trac Complete cannula system in nine colour-coded sizes. During arthroscopic procedures, cannulae provide sterile pathways to the joint that surgeons will treat. The Clear-Trac Complete system, made with clear and colour-stable Eastar copolyester, enables surgeons to identify separate cannulae during surgery and find the best fit based on the size of the patient, the size of the joint being treated, and the thickness of the muscles around the joint. The clarity of the material provides surgeons with an unobstructed view of the instruments and the suture inside them, as well as the bone and soft tissue that surround the surgical site.

In addition to colour coding, medical teams often need high-clarity, colorless materials for devices. Polymer clarity provides healthcare practitioners with an unobstructed view to detect foreign substances, bubbles, clot formation, and fluid levels. Recognizing potential issues immediately can prevent significant problems, such as an embolism or insertion site infection, from developing. 

 Glasslike clarity is also closely associated with cleanliness. If a medical device is not clear, or if it is slightly discolored or its colour  has shifted as a result of sterilization, clinicians as well as patients may question its sterility and safety. Some nurses report that a dark or discoloured device will be thrown away and not used because such discoloration makes it appear to be old and outdated. Clear, colourless devices allow easy monitoring of fluid levels, inspection of a IV site to determine whether an infection is present, and monitoring of fluid colours to determine whether blood is present in a drainage line, for example. 

Medical device manufacturers must take colour shifting during sterilization into account to ensure that devices maintain clarity and intended colour quality. With varying material options available, manufacturers and processors must understand the effect of sterilization on polymer properties. In addition to improving the colour and clarity of high-performance materials, material suppliers must continue innovating to develop more-reliable material options that minimize the trade-offs of color stability, toughness, chemical resistance, and processability associated with many materials available today.

How Sterilization Affects Materials
The objective of sterilization is to reduce the bioburden to zero pathogens while minimizing any change to the physical and optical properties of the final part. Autoclave, ethylene oxide (EtO), gas plasma, and exposure to gamma or E-beam radiation are common sterilization methods that have varying effects on colour shifts of materials used for plastic components or devices. Selecting the preferred technique for any medical device is critical and must include a thorough evaluation of the interactions between the materials and the sterilization method, especially when clarity and accurate colour of plastic components or devices are crucial.

Autoclave Sterilization. An autoclave uses high temperatures and humidity to kill microorganisms. These harsh conditions can cause most common polymeric materials to warp and distort, rendering them useless. In addition, the high temperature and humidity can break down the molecular weight of some polymers through hydrolysis. Polymers that have undergone significant hydrolysis are more susceptible to breakage because their toughness is compromised due to the lower molecular weight. Autoclave sterilization techniques do not typically cause significant color shifts of polymeric materials.

EtO Sterilization. EtO relies on the toxicity of the gas to kill microorganisms. Using EtO to sterilize medical devices can be a relatively slow, three-step process: 

■ Preconditioning—exposing the packaged devices to elevated temperatures and humidity.
■Sterilization—introducing EtO into the relatively hot, humid chamber (maximum temperature between 60° and 80°C).
■Aeration—degassing the device and package to remove the toxic EtO before shipping,

Like autoclave sterilization, EtO sterilization also does not typically cause significant color shifts. It can be the most economical method for low-volume devices and parts that are heat sensitive. This method is a good choice for plastics that may undergo physical property degradation when expososed to radiation.

Gas Plasma Sterilization. Hydrogen peroxide gas plasma sterilization provides safe, nontoxic, dry, and low-temperature sterilization in about one hour. The plasma environment generates an ionic and free radical rich environment that reacts with microbes, killing them or otherwise rendering them harmless. Water and oxygen are the primary by-products of this sterilization method, so there is no need for aeration, as required for EtO. One of the disadvantages of gas plasma is that the reactive sterilizing environment may not penetrate well, especially in long channels or devices. Gas plasma sterilization methods typically also cause no significant colour shifts in polymeric materials.

Radiation Sterilization. Exposure to gamma or E-beam radiation is a very quick, highly productive device sterilization method. It is exceptionally useful for high-volume applications with consistent pallets and packaging, because it can take advantage of high throughput. The major disadvantage of gamma radiation sterilization is that a cobalt 60 radioactive source is necessary, which requires special handling and extra costs. Exposure to E-beam radiation is a sterilization technique without the difficulties associated with a radioactive source, but it has limitations in penetrating high-density materials such as metals.

Gamma and E-beam radiation easily penetrate both packages and devices to kill or disrupt replication of biological materials by exciting molecules to high-energy states. These methods lead to ionization, bond breaking, cross-linking, or chain scission. Unfortunately, these radiation methods do not discriminate between microorganisms and the polymeric materials used in the device or packaging. The radiation also excites the polymer’s molecules to high-energy states. The mechanisms to dissipate the energy include bond breaking (lowering the molecular weight of the polymer, eventually leading to embrittlement), cross-linking (also eventually embrittling a polymer), recombination (with essentially no effect on the mechanical properties of a material), and rearrangements that can result in the formation of colour bodies (which may fade slightly over time). Each of these energy-dissipating mechanisms occurs at different rates depending on the polymer, leaving some polymers extremely discolored upon exposure to radiation and others essentially untouched. 

Polymeric Materials and Radiation Exposure
If retention of highly accurate colour in a device is critical, EtO, gas plasma, or autoclave sterilization methods typically have little or no effect on the colour shift and colour variability of a device. 

If gamma or E-beam radiation is preferred for cost, speed, low temperature processing, or other reasons, it is important to understand how to minimize the effect on optical properties through proper material choice. It is critical that medical device manufacturers are aware and educated on the effects of sterilization, which can vary depending on material differences and the dose and source of radiation.

One of the most critical material effects of sterilization is color shifting, particularly because color coding and clarity play such vital roles in the function and reliability of medical devices. Polymers exposed to radiation often shift in colour to yellow. For healthcare practitioners, any discoloration or property degradation is a cause for concern. Medical device manufacturers and processors must make educated material choices and work closely with material suppliers to select polymers that offer minimal colour shift after sterilization.

Measuring Color Shifting
The effects of color and optical clarity on a material vary depending on the type and dose of radiation, as well as the length of time elapsed after irradiation. A materials manufacturer conducted a study to identify the effect of gamma and E-beam irradiation on several polymers, including medical-grade copolyester, gamma stable polycarbonate (PC), transparent acrylonitrile butadiene styrene (TABS), and acrylic (PMMA). 

In the study, plaques of each material were injection molded under conditions typically used to process the polymers. Next, the initial colour of the plaques was measured using a HunterLab UltraScan Sphere 8000 and reported using the CIE (International Commission on Illumination) b* colour scale. In the CIE b* colour scale, increasing positive values indicate increasing yellow colour, while negative values indicate blue colour. Following initial colour measurement, the plaques made from each polymer were exposed to 50 kGy of gamma radiation to simulate a typical medical device validation test. Separate plaques made with each polymer were also exposed to 50 kGy of E-beam radiation. Following exposure to the radiation, the plaque colour was remeasured with the HunterLab color method described above at various intervals with the final measurement at 42 days to monitor the initial colour shift and decay over time. Photographs of the plaques were taken before exposure and at 42 days.

The results demonstrated that gamma and E-beam irradiation can affect the colour of various polymer materials differently. After 50 kGy of gamma radiation, each of the materials showed a positive shift to higher b* values (see Figure 1), indicating yellowing. The Tritan MX711 copolyester showed the least amount of initial yellowing with a shift of only about two b* units. The acrylic, TABS, and PC materials all shifted more than 20 b* units when measured three days after initial exposure to the gamma radiation. Over time, the yellow color faded in each of the test samples, resulting in a final b* value within 0.2 units of the initial colour for the Tritan MX711 sample after 42 days. The final colour for the TABS and acrylic samples faded to within approximately six and nine units of initial colour, while the PC sample faded the least, with a final colour shift of 17 units. Photos of the plaques before and 42 days after exposure to gamma radiation are shown in Figure 2. 

Similar results were observed after the materials were exposed to E-beam radiation as shown in Figure 3. Tritan MX711 had the lowest yellow shift of any of the materials with a measured b* shift of 4.3 units. The TABS and acrylic shifted approximately 11 and 8 b* units respectively, while the PC shifted the most, with a measured change of 17 b* units. Again, the colour faded back toward the initial colour over time, with the Tritan MX711 sample coming to within 0.5 b* units. The TABS and acrylic samples final shift was slightly less than 3 b* units, while the final shift in colour for the PC sample was more than 9 b* units. Figure 4 shows the molded resins before and after exposure to E-beam radiation.

Conclusion
The proper choice of materials that are compatible with the desired sterilization methods can result in optimum functionality and perceived quality of medical devices. Gamma and E-beam irradiation sterilization methods can cause a significant colour shift with some materials, such as TABS, acrylic and PC. Gamma irradiation was found to cause more of a colour shift than E-beam irradiation in the materials studied. Tritan copolyester MX711 showed the least amount of color shift of all the materials studied, while gamma stable PC was found to have the greatest overall shift in colour.

In summary, medical devices often depend on clear and tinted materials for functional and aesthetic reasons. To optimize retention of the desired colour of clear or tinted devices, manufacturers need to be aware of the effect of sterilization methods on shifts in colour of their devices. Plasma, EtO, and autoclave sterilization methods have minimal effect on the colour of typical clear plastics used, but radiation methods can have a big effect. If radiation methods are used for sterilization, copolyesters are shown to have the lowest colour shift of any of the materials examined in this study.

Scott A. Hanson, PhD, is the global industry leader of the medical segment at Eastman Chemical Co. (Kingsport, TN). Rachel Turner is manager of marketing insight and strategy at Eastman.

Published in MD&DI, July 2010, Volume 32, No. 7
 

A virtual brain is predicting how aging impacts us all

Located at Baycrest, a world leading academic health science centre, RRI (Rothman Research Institute) is at the forefront of the quest to understand how the brain ages and mitigate factors surrounding the development of diseases such as Alzheimer’s and problems such as stroke. By bringing together world-renowned researchers in a broad spectrum of disciplines, from cognitive neuro-pyschologists to computer scientists, RRI is able to tackle its goal of understanding the workings of memory and the functions of the brain.

According to  Dr. Randy McIntosh, senior scientist and director of RRI, the focus of the research at the Institute is to understand both the aging brain and age-related diseases and disorders.  A leader in the CNS field, Dr McIntosh has been working on developing a unified theory of brain operation that emphasizes the integrative capacity of the brain. “The idea is to understand how different kinds of mental functions change as we age, how these functions can be worse if they’re accompanying disease but also understand ways to try and stave off these changes,” he explains.

The research focuses on understanding the neuro-basis of those changes in terms of cognitive theories for memory and attention. “We aim to use information obtained from neuro-imaging technology to develop more effective ways of staving off the declines. We strive to develop cognitive rehabilitation strategies and try to remediate the more protracted kind of decline that comes with things like mild cognitive impairment, dementia and/or stroke. We also focus on tracking the efficacy of those therapies by once again using neuro-imaging technology as a way of validating that those therapies have direct benefit.”

The benefit of working at an institution such as RRI is that it brings together a group of researchers from a divers range of disciplines, all devoted to solving a common problem. The varied backgrounds of the scientific staff at RRI allows for unique solutions to be engineered. “If you address that problem form a number of different perspectives, the solutions to that problem end up being much more innovative than they would be if they were addressed from only one discipline,” says MacIntosh.

In trying to understand memory, he explains, the typical approach has been to let psychologists address it in a traditional environment such as a university. But the idea behind RRI has a much broader scope. A diverse group of psychologist, engineers, neurologists, physiologists and computer scientists, all approach memory from different avenues with their contrasting back grounds allowing them to foster new solutions.

“Addressing a challenge from different perspectives brings different ideas to the table. You come up with solutions that would not be possible if you focused on only one particular way of looking at the world, says McIntosh. At RRI, perhaps the best example of this process incorporates a combination of strong cognitive theory and modern neuro-imaging technologies while looking at the computational or informatics aspects and trying to merge theory with data to develop large-scale computational models of the brain and how it changes as we age.

“Our next step is to develop what’s been called the virtual brain which is actually a model of the human brain that allows us to understand not only how the brain functions in a normal state but also how the brain  functions as we age, “ said McIntosh. “You can make a virtual brain that actually ages, a virtual brain that gets Alzheimer’s disease, a virtual brain that gets a stroke and develops the algorithms that help explain how the brain tries to adapt to age and adapt to damage and disease.”

McInstosh explains that the virtual brain is built from structural information collected from neuro-imaging at RRI in combination with functional information and brought together with high-level mathematics to model the brain in action.

“We’re really merging the math with the ‘wet-brain’. This allows us to include the necessary dynamics captured in the math that drive the model,” said McIntosh. “You get structural MRI, for example, that you can use to image the connections in the brain. You then use that as your architecture and then impose the dynamics on top of that using the neuro-network theory. The virtual brain actually ends up being an amalgamation of both normative data but also the clinical that we have access to as well.” he says.

Bringing the research back to its real-world applications and the looming concerns of an aging population, the end-goal of the research, is prediction. People generally associate Alzheimer’s with the aging brain but what about those individuals who develop these diseases in their 40’s? The idea is to use the virtual brain as a way of testing whether that person is showing some kind of random abnormality, over and above what you can see with the regular clinical imaging.”

Using the information gathered from the neuro-imaging technologies, one can then apply a specific person’s characteristics to the virtual brain. From this, researchers can then compare brain functions in the virtual environment to see how the virtual brain’s patterns show similarities to someone who has, for example, dementia.

“It ends up being a sort of diagnostic tool and a prognostic tool” says McIntosh. “In theory, you could use that virtual brain to help guide the course of therapy. This could help a physician decide what potential pathways one can stimulate to help the brain recover after a stroke for instance.”

Recovery is definitely what they’re after. Previously, it was thought that the brain didn’t change after the first 20 to 25 years of life. RRI is leading the charge to reshape that theory.

“The most significant work coming out of Rotman is the recognition that the aging brain is in fact… malleable,” says McIntosh. “For a number of years, the assumption was that once you’re were 20 to 25, your brain didn’t change anymore. What we’ve shown is that the brain does change the way it does things pretty much across its lifespan. There is this idea of plasticity or adaptability that’s in brain function throughout life, and what that does is actually improve the potential. It give us hope that one can make use of that flexibility, then potentially remediate cognitive function.”

It truly is hope to the millions that are affected by these problems, a fact that certainly isn’t lost on McIntosh. The translation from research to reality can be long and arduous both these problems are fast becoming some of the most pressing concerns of life sciences.

“There’s been a difficulty, I think with that translational aspect. Part of it is structural, in that a lot of research is done without a direct link into the clinical domain part of it is sociological as well: ocne this stuff gets published it take a while for it to filter down to the applied into things,” he says.

"There are models developing. That’s one thing we’re trying to do at Rotman, it’s trying to make sure that the clinical research and the translational component is actually part of the way the Institute is structured. So that when there is the potential for translating the basic findings into a clinical or applied domain, we can do that in-house and actually get the validation part of it done much more quickly.”

With baby boomers now reaching their “golden years” there is an urgent need for new treatment options for the unprecedented large proportion of older Canadians. It makes the CNS field and particularly RRIs groundbreaking research very timely. In the past, McIntosh, says that neuroscience has been about explaining a condition after it was too far-gone. Now a shift is occurring where trying to pick up the warning signs early is taking over as the dominant point of view.

“As people age, the number of these core morbidities are going to factor into quality of life and become more difficult to manage so the more we can get it early, the better off we all are,” says Dr. McIntosh. “That why I think it’s important to not only understand the diseased brain but also what keeps the brain healthy for longer period of time. And that’s why this research into the brain and aging is so important. We can understand not just the bad parts about aging and the brain but also the good parts and how to make the good parts more prevalent for the boomers”.

This article was edited from the May 2010 issue of Biotechnology Focus.  

Nuclear physics delivers

ScienceDaily (Mar. 4, 2010) — Time taken to detect brain tumours could soon be significantly reduced thanks to an ongoing pioneering project led by the University of Liverpool with the Nuclear Physics Group and Technology departments at the Science and Technology Facilities Council (STFC) at Daresbury Laboratory. Project ProSPECTus is developing the technology for next generation SPECT (single photon emission computed tomography) imaging that is set to revolutionise the medical imaging process, improving future diagnosis of cancer and the probability of successful cancer therapy whilst enabling a higher throughput of patients in hospitals.

Project ProSPECTus is based on a form of imaging known as SPECT which detects gamma rays emitted by a tiny amount of a radioactive pharmaceutical which is injected into the body. SPECT is a widely used method of imaging in many areas of medicine providing 3D functional information about the body, which is typically presented as cross-sectional slices through the patient. It is most commonly used to test the functioning of the heart or for the detection of tumours. Conventionally, SPECT imaging uses what is known as an 'Anger Camera' which relies on a collimator, a filtering device with many small holes, which lets just some gamma rays through and relies on geometry to identify exactly where they are coming from in order to build a picture of a biological process happening inside the patient.

 However, ProSPECTus has taken a fundamentally different approach and has developed its technology based on what is known as the 'Compton Camera'. This identifies the origin of the gamma rays without the use of a collimator, meaning that much less of the radiation used in the process is wasted, so the radiation is used more efficiently. It has not been possible to do this successfully before. However, using brand new, cutting edge detector systems, ProSPECTus is now building a prototype SPECT imaging system, using the Compton Camera principle, that is one hundred times more sensitive than existing clinical SPECT systems. This increased sensitivity offers two benefits- either the dose of radiation administered to the patient could be reduced or alternatively more patients could be scanned by one machine in a day if the current dose is used.

 These new cutting edge detector systems, designed by the University of Liverpool's Nuclear Physics research group alongside the Nuclear Physics Group at STFC Daresbury Laboratory, are a direct spin out of AGATA (Advanced Gamma Tracking Array), a nuclear physics research and development project with the aim of building the next generation gamma-ray spectrometer. ProSPECTus is funded from STFC's Particle and Nuclear Physics Applied Systems (PNPAS) programme, a scheme aimed at exploiting techniques developed in blue-skies basic research projects like AGATA so as to generate knowledge exchange into the areas of health, security and energy applications.

Dr Andy Boston, the project spokesperson, at the University of Liverpool said: "Not only is ProSPECTus' technology a hundred times more sensitive than that of the traditional Compton camera, it is unique in that it will also be possible to operate it simultaneously with MRI (Magnetic resonance Imaging), which has never been an option due to the MRI's strong magnetic field. In fact, it will be possible to fit this SPECT system retrospectively to the 350 or so existing MRI scanners across the UK. For patients this means fewer appointments, earlier and more effective diagnosis of tumours, which means higher probability of effective treatment.

The higher sensitivity camera also offers the scope for shorter imaging time and lower doses of radiation, which is highly beneficial for patients who require frequent scanning. For clinicians, this means that more patients can be seen in a day. This is a truly collaborative effort between the Nuclear Physics Groups both at the University of Liverpool and STFC Daresbury Laboratory, working with STFC's Technology teams who will design and build the detector cryostat and with the essential support from Liverpool's Magnetic Resonance & Image Analysis Research Centre (MARIARC) who provide the MRI expertise."

Ian Lazarus of STFC's Nuclear Physics team at Daresbury Laboratory said: "ProSPECTus has taken the abilities of the Compton imager to a new level. This is a particularly exciting example of how technology emerging from one nuclear physics project, in this case, AGATA, can have a direct and positive impact on the future wellbeing of our society."

 Article taken from http://www.sciencedaily.com/releases/2010/03/100303113956.htm

Life cycle assessment is a useful tool for manufacturers as they become more accountable for the effect they have on the environment.

This column is based on an article which appeared as Designing sustainable medical devices in the July 2009 issue (volume 31, number 7) of MDDI, the magazine of the Medical Device & Diagnostic Industry.

Stakeholders in the medical device manufacturing industry are becoming more concerned about the environmental impact of their products and processes. These effects range from the potential negative effects of substances such as phthalate plasticizers leached from plastic products to emissions resulting from the incineration of disposed products. In addition, consumers are also becoming more aware of the negative impact that manufacturers can have on the environment. To combat such effects, consumer advocacy groups are demanding products that are more sustainable.

Sustainability as a competitive advantage

Government initiatives continue to increase environmental awareness through the development of new policy and legislation. This in turn is encouraging industry to become more accountable for the environmental impact of their products and operations. For example, the Waste Electrical & Electronic Equipment (WEEE) Directive and the Producer Responsibility Obligations (Packaging Waste) regulations of 2008 have set precedents regarding end-of-life disposal of products involved in their industries. It is only a matter of time before regulatory bodies start initiating changes in policy for other manufacturing sectors. Such regulations could well make it more difficult for companies to develop new products, at least in the short term.

 In such competitive environments, new product development can no longer rely solely on traditional criteria such as cost, quality and delivery. Effective environmentally sensitive product design enables manufacturers to gain a prominent competitive advantage in the development of “green” products. As a result, more and more businesses are adopting environmental management systems to organize and assess environmental effects, and meet the growing demand from consumers and legislation for green products.

 The ISO 14001 standard, “Environmental Management Systems–Requirements with Guidance for Use” sets guidelines to enable businesses to recognize the environmental effects of their products and processes. In order to qualify for ISO 14001 accreditation, a company must identify its overall environmental impact and determine the significant effects of its various products, while also demonstrating continual improvement in its manufacturing processes.

Life cycle assessment

Life cycle assessment (LCA) is a useful technique to evaluate the environmental impact of products, identify problem areas, and make improvements at the most effective stage of a product’s life cycle. Various studies have shown the benefits of performing a LCA at the product design stage to effectively lower a product’s overall negative environmental effect.

One tool used to make such an assessment is a LCA software packaged called SimaPro. It uses Eco-Indicator LCA methodology to aid manufacturers in selecting the most environmentally suitable materials for its products. The Eco-Indicator method provides impact assessment and ecodesign scoring. While there is no doubt that a detailed LCA is an extremely useful method for environmental impact evaluation, it can be costly and time-consuming, and the results can be difficult to convey to nonexperts such as consumer and environmental advocacy groups.

In-house web-based tool

Although there are various LCA software available, they can be difficult to use on a large range of products. The user must have prior knowledge of LCA inventory databases and internal product details before starting an LCA. The information needs to be entered manually into the program for each each product. The process is time-consuming and usually needs to be carried out by an experienced LCA practitioner. In some cases, materials used in a given product may or may not be present in the LCA inventory. This means the assessor now has to choose the closest substitute. This can introduce error into the results of the assessment.

 Some companies are working their way around these challenges by innovating new approaches. For instance, a manufacturer of a single-use respiratory-care device has developed an in-house tool that performs a streamlined LCA on products using existing company data to obtain an immediate environmental impact score for any product it manufactures. Internally, although the tool was developed to aid in the design process, it also has value in other departments, because the system provides a baseline score that enables product comparisons.

 Departments can use the tool to set targets to lower a specific product’s environmental impact and identify areas of high environmental concern when designing, purchasing, and marketing products. Once widespread, such a tool would aid manufacturers in the decision-making process. The following example is a real-lfie scenario of how manufacturers can develop a similar tool to aid designers in developing more sustainable products.

 One company stored information relating to its products in standard structure query language databases managed by Efacs, an electronic database and software program. The Efacs system was used to organize the company’s data and contained features such as the bill of material (BOM) for each product. Each product BOM provided detailed information on the product and was organized in a hierachical structure. Information included all components, subcomponents, and even specified packaging in terms of weights and materials involved.
 

Gathering environmental data

The company used LCA software to collect the environmental data for the scoring tool and chose the EcoIndicator 99 methodology. The process involved creating a project within the scoring tool that calculated an environmental impact score for all materials and processes. It also incorporated the required disposal scenarios of landfill or incineration. The figures were stored in a separate material scores table.

The first step involved collecting a list of all the materials and finding them (or the most appropriate substitutes) within the scoring tool databases. The next step involved calculating the environmental impact using Edo-Indicator 99 methodology.

Because the scoring tool is Web based, users have easy access to the data. The user can type any component part or product code that the company manufactures into the tool. Once the part code is entered, the scoring tool must read data from the BOM. The results of the BOM is dsiplayed in the table, showing part number, description of the part, material number, description of the material, generic material type, and weight of the material. The system then calculates the total quantity of each material used for each part (if more than one is used). The tool displays a dropdown menu for each material so that materials can be changed, and the button to calculate the score is activated only once all the fields are completed.

When calculating the score, the tool gets information from the populated scores table by multiplying quantities with score values. The results are then summed for each selected product and displayed in a report for landfill and incineration disposal scenarios.

 The simple-to-use Web-based tool enables the streamlined LCA of a product to be carried out in as little as two steps. This is important, because in order to design a more sustainable product, the designer needs to benchmark the existing product. New product designs are usually based on products already in production. The first use of the tool is to score the existing product to provide a benchmark. Once a benchmark is set, targets can be determined and improvements can be recognized. Because the products are made of components and subcomponents, the tool can change the materials and weights based on these. Any changes are reflected in the scores that can be compared side-by-side with the benchmark.

 The tool also has dynamic features that allow designers to change and compare products in five steps. The designer can also view product BOMs, add new components or remove existing components, change materials alter the weights involved, and compare the environmental impact of designs side-by-side. All the design ideas can be saved to a file for future reference.

Challenges remain but the course is set

The environmental scoring tool achieved the objective of quick and accurate impact scores for existing products, setting the benchmark to design more-sustainable products. Error is greatly reduced when comparing products because the environmental impact scores for selected materials have already been decided. Having access to such data precludes the need for the user to have prior knowledge of the environmental effects of different materials and products. These features mean the tool can be used by nonexperts of environmental LCA and provide accurate results, unlike traditional LCA software. The scoring tool also runs from a live database that eliminates error associated with incorrect data input, and products can be scored in seconds rather than hours.

As is often the case when it comes to manufacturing considerations, the medical device industry poses special challenges with regards to environmental issues. Medical devices involve additional environmental factors that have not yet been taken into account in generating an environmental impact score at this early assessment stage. For example, the additional environmental impact associated with the leaching of phthalate plasticizers from plastics. There are also the effects of product sterilization (of which a variety of techniques are used) before and after use, which have not yet been included. These processes and others like them will have to be added at a later stage

Another important limitation is the lack of available environmental data for thermoplastics elastomers and biopolymer materials, which may end up being used in future products. Estimates, however can be made by manually performing an LCA using existing data on raw materials and processes. Research in these areas will be used to develop the environmental scoring tool to aid in designing future sustainable medical devices. The process has really only just begun. A whole new generation of greener, more environmentally benign products will definitely see the light of day.

That crunching noise you hear is the sound of endoscopes shrinking. Medical diagnostic and therapeutic procedures are growing smaller, from neurology to podiatry. Minimally invasive surgery (MIS) is shrinking to the point that incisions can heal without sutures, and the new words of the day are “endoluminal” and “NOTES” (natural orifice transluminal endoscopic surgery), both implying procedures done via natural body openings, with no external incisions.

Endoscope remains
the workhorse
But how do the doctors performing these miracles see inside their patients? Various new and experimental technologies seek to five doctors with now direct visual access the equivalent of x-ray vision. But for most of these new procedures, the workhorse of visualization remains the endoscope.

Direct visualization via endoscopy provides the clearest image for doctors. It is the gold standard against which other technologies are weighted for effectiveness. For example, in comparison between MRS and spectroscopy systems, arthroscopy has been used to judge the performance of each. According to the literature available, endoscopy demonstrates the following attributes:

-          - Offers a track record of procedural success.

-          - Enables real-time visualization to precisely guide placement, as well as use of intruments, vastly reducing potential for malpositioning or damage.

-          - Also enable doctors to see as a patient is manipulated (e.g. as a shoulder is rotated during surgery, via arthroscopy)

-          - Provides greater portability than other similar technologies.

Together, these factors mean endoscopy offers accuracy, flexibility, and breadth of use, particularly in therapeutic applications, Many studies bear out this claim. Magnetic resonance images (MRI) of musculoskeletal joints including soft tissue, for instance, are notoriously problematic. Estimates of false positives for pathological knee MRIs reach as high as 20%, creating complications for patients and adding costs for insurance providers. In some studies, MRIS barely outperformed clinical examinations. In other areas, such as diagnosis of scapholunate ligament injury, MRI failures have been severe enough that studies have concluded they simply should not be used.

Despite these studies, endoscoppy has historically been underused in many applications. MRIs still dominate advance diagnosis of knee and shoulder pain. Why? Because traditional arthroscopy has been perceived as highly invasive, requiring fairly large scopes (2.7-4mm. diameter), and thus full anesthesia in a hospital or surgical centre. Conversely, MRIs are noninvasive. Given the perception that arthroscopy requires hospitalization or at least an advanced surgical centre, doctors have not traditionally viewed arthroscopy as a comparable potential of office revenue.

The perception of endoscopy as highly invasive is changing as technology improves. However, there are still challenges that must be met.

Nonsurgical endoscopy has been hampered somewhat by technological challenges. When endoscopic systems are shrunk beyond traditional endoscopy (say, to sizes below 1.5 mm OD) pixelization and brittleness can occur. Microdiameters limit fiber size and the ability to carry light. Smaller systems mean less room for everything: light fiber, image fiber, coatings, and other materials that increase durability.

There are also challenges in trying to connect microendoscopes to the cameras that doctors use, and ultimately to the endscope tower that offer video image display and capture options. Working with scopes in the 1mm range has been likened to trying to control a strand of cooked spaghetti.

In addition, microendoscope systems can be difficult to manufacture reliably and with cost stability. Making a small number of experimental prototype microendoscopes that sell in the $7,000 range is one thing. Finding reliable, repeatable manufacturing technologies that allow production runs in the thousands and affordable scope prices is a challenge. But it’s the mass-produced scoope that can benefit doctors, patients and insurance companies.  

All the difficulties associated with designing and manufacturing microendoscope systems must be resolved in an integrated way that provides seamlesss end-to-end imaging and service.

Several visualization options other than traditional endoscopy are in use or under development to support minimally invasive procedures. Some of the most promising include the following. 

Capsule endoscopy:
This integrated endoscopic camera, relay lenses, and transmission system is the size of a large multi-vitamin. Patients swallow the device, which enables clear and continuous transmission of images that, in many cases, can replace gastroscopy and colonoscopy. There have been issues with capsules not being eliminated requiring further medical attention. A limitation of capsule endoscopy is that the doctor cannot control the capsule’s movement. Nonetheless, capsule endoscopes have been used in diagnostic procedures. 

Nanotechnology cameras:
Several nanotechnology camera systems exist or are under development, including some potentially small enough to travel through the circulatory system. These exciting systems are for diagnostics, but they do not yet enable manipulation and thus have no immediate therapeutic value.

Single-fiber endoscopes:
Hair-thin single-fiber endoscopes break out visible light by color and use spectrographs to generate virtual 3-D images. These offer interesting possibilities for extremely small incisions, if inherent issues of fragility and brittleness can be addressed. The clarity and procedural usefulness of images generated via spectrography also require further study.

Robotic image-guided systems:
Robotic image guidance systems use microcameras isnerted with surgical instruments and electromagnetic devices to track location, overlaying the information using fast 3-D visualization to generate real-time live images, some in high definition. Such systems are being used in pioneering forms, for example, Intuitive Surgical’s daVinci robotic surgical system.

Virtual imaging:
Potential real-time visualization systems are emerging from virtual image technologies. These devices fuse images generated by different noninvasive technologies (such as MRI and ultrasound) to form composites that combine the best of each technology.

The new procedures enabled by non-surgical endoscopy offer the potential for a paradign shift away from large traditional glass endoscopes. Innovative diagnostic and therapeutic applications will reduce costs for insurers, ease patient pain, and speed healing, while also increasing revenue for doctors and device manufacturers alike.
 
This text is based on an article which appeared in the July 2009 issue (volume 31, number 7) of MDDI, the magazine of the Medical Device & Diagnostic Industry