MD+DI Online is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Sitemap


Articles from 1997 In July


Counting Scales Aid Production of Endoscopic Instruments

Casebook

Counting Scales Aid Production
of Endoscopic Instruments

Provide quick and accurate part counts

Endoscopic surgery demands precision and accuracy. Not surprisingly, these same qualities are required by manufacturers that supply the devices used in this minimally invasive procedure. Boston Scientific/Symbiosis (Miami) manufactures a variety of such devices, including subassemblies for stent-delivery systems, needles, and biopsy forceps. During assembly, every component has to be cleaned, counted, and bagged before being delivered to the manufacturing floor. "We are dealing with thousands of tiny parts," explains Mike Voss, business unit manager for OEM products at Boston Scientific/Symbiosis. "It is crucial that we know the exact quantity."

To help determine the exact quantity of springs, screws, tubing, and other components, the company selected the Series C and CP high-precision counting scales from Setra Systems Inc. (Boxborough, MA). Both models are interfaced with Setra's Auto Count accessory for bar code scanning and label printing. Using Setra's patented variable capacitance technology, these scales offer counting resolution as fine as one part in 750,000.

When Boston Scientific/Symbiosis counts a piece for the first time, the average piece weight (APW) is determined through a sampling process. The scale prompts the operator to count 50 pieces onto the scale pan and press a key. The scale then determines how much one piece weighs, based on the weight of the entire sample. Once calculated, the APW is printed on a bar code label through Auto Count via the RS-232 communication port of the scale. This label is kept on a chart located above the scales.

The APW can also be input at the time of counting. If a bar code label exists for a particular part, the APW is simply scanned into the scale. "We count the same type of parts over and over. It is a great benefit to be able to scan the bar code and have the APW automatically entered into the scale. We are able to count quickly and accurately," says Voss.

Another bar code is placed on the bag of counted parts along with the drawing number and quantity. The bag is then stored in a bin until the parts are ready to be used for assembly. The bin is also labeled with a bar code and additional pertinent information to ensure proper part identification. When a work order comes in for 500 biopsy forceps, assembly personnel can go to the correct bin and take a bag containing the necessary quantity of parts.

According to Voss, the scales are providing a count accuracy of better than 99%. Voss concludes, "In the medical equipment field, time is an issue. It is crucial that we manufacture the parts quickly so our customers can provide the equipment to their clients. The Setra scales have streamlined our operation through quick and accurate counting."

For more information, call Setra Systems Inc. at 800/257-3872.

Return to the MPMN home page

Products Featured on the Cover

Products Featured on the Cover

July/August 1997

In-line filter units designed for TNA emulsions with lipids

A vented, in-line device can be used for pump-driven filtration of total nutrient admixture (TNA) emulsions with lipids. Each Nutrivex filter contains 10 sq cm of polyethersulfone membrane for quantitative removal of particles measuring larger than 1.2 µm. A hydrophobic air vent provides air elimination. The polyester housing enables the unit to be sterilized by gamma or E-beam radiation or EtO. Millipore Corp., 80 Ashby Rd., Bedford, MA 01730. (800/645-5476)


Return to the MPMN home page

Metal finishes improve performance of medical devices

With a surface hardness approaching that of case-hardened steel, two proprietary metal coatings can improve the durability, corrosion resistance, and lubricity of medical devices. NiCoTef coating is deposited through a controlled chemical reaction, making it possible to coat internal surfaces and complex parts otherwise difficult to protect and lubricate. The Nituff aluminum-finishing process enhances the properties of aluminum and aluminum alloys, often permitting the substitution of aluminum for heavier metals. Nimet Industries Inc., 2424 N. Foundation Dr., South Bend, IN 46619. (219/287-7239)


Return to the MPMN home page

Heat-shrink tubing available for medical applications

A family of medical-grade, heat-shrink, single-wall tubing provides good physical and electrical properties and is made of a material that meets USP Class VI requirements. The Altera tubing can be sterilized by gamma or E-beam radiation or EtO; some formulations can accommodate steam or dry heat sterilization. Medical applications include surgical and electrosurgical instruments, diagnostic and therapeutic equipment, and catheter systems. Sizes range from 0.007 to 1.5 in., and walls as thin as 0.0025 in. can be achieved. Raychem Corp., 300 Constitution Dr., Menlo Park, CA 94025. (800/926-2425)

Return to the MPMN home page

Medical Technology Group Formed

Medical Technology Group Formed

Will provide services to California's medical industry

A medical technology group has been formed to help meet the needs of California's growing medical industry. The group was formed by the California Manufacturing Technology Center (CMTC), a private, nonprofit organization that seeks to improve the competitiveness of small and medium-sized manufacturers.

Besides working with device manufacturers, the group also works closely with doctors, dentists, and inventors to identify, develop, and produce new medical products. It assists in the development and validation of internal systems and supports emerging companies' medical entries from conception to market.

The group is based in Orange County, where, according to David Braunstein, CMTC president and CEO, an estimated 2000 medical-related manufacturers are based. "We've formed the medical technology group to provide this vibrant industry with the affordable and objective services it needs to survive and grow," says Braunstein.

CMTC can help companies with extensive FDA regulations requiring greater attention to documentation, verification, and validation of both manufactured products and manufacturing processes. Services include the implementation of such quality systems as GMP, ISO 9000, and CE mark; complete validation services such as software validation and construction, installation, operation, and performance qualification; and human factors, statistical technique, and conventional manufacturing consulting.

CMTC can also assist in the areas of process and business improvements, plant and systems modernization, shop-floor improvements, product design, and workforce development.
For information, call CMTC at 800/300-2682.

Return to the MPMN home page

Spire Receives Patent for Surface-Treatment Process

Coating reduces bacterial growth on catheters

Spire Corp. (Bedford, MA) has received a patent for the development of a surface-treatment process that uses ion beam­assisted deposition (IBAD) to apply thin films to polymer medical components for enhanced bactericidal properties.

Entitled Catheter having a long lasting antimicrobial surface treatment, the patent covers the use of IBAD processes to create an integrated multilayer coating of antimicrobial metal on any polymer used in catheters. Use of such coated catheters reduces bacterial growth and helps keep metal coatings from leaching from the surface of subcutaneous medical devices.

Besides use on the body of the catheter, the process can also be used on cuffs and plugs. There is currently no limitation to the applications covered by this patent; all antimicrobial uses are covered.

Spire specializes in developing processing services for customized surface treatments for the medical device industry. Spire's Ionguard and Ioncide biomaterial surface treatments are used to improve wear and abrasion resistance, infection control, hemocompatibility, biocompatibility, and lubricity of metal, polymer, and ceramic medical devices.
For more information, call Spire Corp. at 617/275-6000.

Return to the MPMN home page

Name Change for Inchcape

Now called Intertek Testing Services

Intertek Testing Services (ITS; Andover, MA), formerly known as Inchcape Testing Services, has announced that it has completed the transition to an independent corporate entity with the debut of its new name and revamped brand identity. ITS was purchased from Inchcape plc in October 1996.

The company offers manufacturers, distributors, retailers, commodity producers, and government agencies testing, inspection, and certification services. The company's quality systems division maintains laboratories and field offices in 61 locations throughout North America, Europe, and Asia.
For more information, contact ITS at 508/689-9353.

Return to the MPMN home page

Tailored Label Products Moves to New Facility

Increases manufacturing capacity

Tailored Label Products, a company specializing in pressure-sensitive labels and tags, has relocated to a larger facility. The move has doubled its flexographic printing and rotary die-cutting manufacturing capacity.

The company's production capabilities include flexographic, rotary presses that can print up to six colors and four-color-process labels up to 16 in. wide. Such services as laminating, slitting, consecutive numbering, and pin-feed hole punching are provided. An art department and a high-speed plate-making department are also located in-house. The company can take on challenging label applications that may require unique materials or converting capabilities.

The firm is now located at W165 N5731 Ridgewood Dr., Menomonee Falls, WI 53051.
For more information, contact Tailored Label Products at 800/727-1344.

Return to the MPMN home page

Workgroup Technology Corp.,

Profile

Design Control Regulations
Simplified with PDM Software

With FDA's new design control regulations into effect as of June 1, medical device manufacturers are quickly moving to adopt document and process management systems to control design documents. While instituted primarily for the purpose of meeting regulations, these systems are having additional benefits. Companies are finding that they are increasing their overall operating efficiencies as well as shortening their time-to-market cycles.

One company that has already begun meeting the new regulations is Medrad (Pittsburgh), a leading manufacturer of fluid-delivery and magnetic resonance imaging products. While the business has always been well run, over the years different departments within it struggled to manage the voluminous amount of data that were stored during the design and development processes.

For example, its document control group was using an aging Rbase database designed in the 1980s to store current files, while older versions were stored off-site at a cost of several thousand dollars each month. Rbase provided no control over historical files because it didn't contain the files themselves, only information about them. Further, it offered few data validations and provided no links to files.

At the same time, Medrad's engineering design and services group, which manages all of the company's electronic product documentation including Pro-Engineer CAD models and mechanical drawings, recognized an opportunity to improve the management of its current and historical files.

FDA, ISO Requirements

At a higher level, Medrad wanted to more efficiently meet the increasingly stringent regulations required by FDA. In addition, it sought to simplify the process for receiving ISO 9001 certification.


FDA requires that medical device firms maintain a device master record (DMR), which is the recipe for how the product is to be made. It contains all the product documents outlining the manufacturing processes and specifications. FDA also requires a device history record, which is a record of all the steps actually performed to produce the product.

All documents in the DMR must be under revision control. It is not unusual for FDA to check to ensure that the right configuration of documents was used on a particular date to build a specific device identified by its unique serial number or lot number. Maintaining all these documents and configurations is very difficult to do manually. For example, in order to prepare a DMR for even a small product line, Medrad might need to spend six to eight weeks manually going through documents and distinguishing which ones would be required to build a specific configuration. Then, within a day, the configuration could become outdated because of changed parts or procedures.

ISO 9001 requirements also pose a challenge to device manufacturers. ISO 9001 requires companies to document all their procedures and prove that they are followed. It includes the management of product documentation and the control of the design procedures.

Given these demands, Medrad determined that a product data management (PDM) system was the best way of addressing them and formed a five-person team that drew up a list of 30 potential suppliers. That list was quickly whittled down to 15 based on the need for a solution that could accommodate diverse hardware, operating system, and database requirements.

Then, after participating in demonstrations and more research, the group focused on three potential suppliers. Medrad brought each of the three vendors in for a week and had 16 key users gain hands-on experience with the products. Based on the results of a user survey that followed these sessions, the company selected the CMS PDM system from Workgroup Technology Corp. (Lexington, MA).

Key Selection Criteria

According to Paul Kwiecinski, Medrad's PDM project manager, there were several key reasons for the decision. "We really liked Workgroup Technology's focus on tool integration," he says. "For example CMS/Pro is a tight integration between CMS and Pro-Engineer, which enables our engineers to manage the complex configuration of files generated during product design."

Kwiecinski continues, "We also appreciated CMS's graphical file structure browser, which allows users to see how information is organized. In addition, CMS was easier to use than competitive products. With CMS, Medrad could tailor the custom attributes screen with its own data without any programming. Another PDM product required all documents to be stored in its own proprietary format, whereas CMS could retain information in its native format."

From an information systems standpoint, Medrad liked CMS because it allowed the company to define the applications that launch and work with CMS. "At the time, we did not have a corporate standard for word processing," Kwiecinski says. "CMS enabled us to select different viewers based on the individual PC desktop."

Time-to-Market Savings

Today, Medrad has control over a broad array of files, including WordPerfect, Word, Excel, Lotus Pro-Engineer, and others. "Now, our users can go through CMS, look up the document they want, and obtain it," explains Kwiecinski.

"We estimate that our R&D and mechanical engineers save up to two days a month just searching for information. That's significant to our organization. We can obtain information directly at the desktop without making special requests. CMS also gives us a lot better control over the different versions of each of the files. We no longer have new versions in-house and older versions sent off-site."

Moreover, Kwiecinski adds, "When a user puts in a change request today, the drawings and documents are directly affected by the change. With CMS, associations are made from the change request back to the original control documents. This means that when users look at change requests, they are assured of looking at the original document, and vice versa. Now people can see that association; we never had that with our old system."

In the past, Medrad could not easily view older revisions of documents. "Now," says Kwiecinski, "we have quick access to all revisions, no matter how many times a document has been changed. That has proved to be very beneficial. Today we have an automated audit trail to more quickly and easily meet FDA regulations and ISO 9001 standards."

Meeting Regulatory Requirements

From a regulatory perspective, CMS has performed well. "FDA was impressed with our demonstration of how CMS would enable us to meet its regulations," Kwiecinski says. "When it saw CMS, FDA said our method would exceed its requirements. They had suggested that we keep a separate device master record for each configuration of our injectors, and we have more than 650 different configurations. CMS will accomplish this so we will be fully FDA compliant." CMS has helped Medrad maintain better documentation in its device master records and device history records. The same process that could have taken six to eight weeks can now be handled on-line in minutes.

"Overall we believe CMS will play an important part in helping us get our products to market more quickly," Kwiecinski says. "This is extremely important in the medical device market. We estimate that CMS will provide our engineers with at least 10% more time to do their jobs. In conjunction with a number of other programs, this should have a significant impact on reducing our cycle time."

For more information on PDM software from Workgroup Technology Corp., call 617/674-7629.

MPMN is actively seeking success stories like this. If your company has one to tell, please contact Managing Editor Ursula Jones at 3340 Ocean Park Blvd., Ste. 1000, Santa Monica, CA 90405; 310/392-5509.

Return to the MPMN home page

EMI gaskets

Spotlight on IV Components

EMI gaskets

The shielding performance of a spiral gasket has been combined with the sealing of an elastomer. The Flexi-Shield gasket resists compression set, comes in a very-low-force version, and is as easy to handle and use as a rubber elastomer. It is groove mounted and flexes easily to conform to various shapes. The spiral design flexes to fill uneven joint surfaces and has no pieces that could break off and short out equipment. Standard materials are stainless steel and beryllium copper, and tin plating is available for better conductivity or corrosion resistance. Cross-sectional diameters range from 0.063 to 0.125 in. Spira, 12721 Saticoy St. S., North Hollywood, CA 91605. (818/764-8222)



Grounding cable clamps

Lightweight resin-made grounding cable clamps are copper plated to ensure simultaneous fastening and grounding for power/signal coaxial and braid shielded cables in the diameter range of 0.118 to 0.315 in. The elasticity of the resin material and the high conductivity of the copper plating provide stability of the electrical contact, even under conditions of heavy vibration. Intermark Inc., One Penn Plaza, Ste. 4526, New York, NY 10119. (212/629-3620)



Combination hook and stick shielding

Combination hook and stick EMI/RFI shielding provides good durability because the leading edge of the gasket actually hooks over the mounting flange for full protection. With one side hooked over the flange, and the opposing side attached by pressure-sensitive adhesive, beryllium copper hook-on shielding offers a self-locating, secure installation for bidirectional applications. The gaskets provide EMI/RFI shielding to 100-dB attenuation levels. Smooth to the touch, they require only a low closing force while providing 360° of snag-free operation. Tech-Etch Inc., 45 Aldrin Rd., Plymouth, MA 02360. (508/747-0300)



Shielding structure material

An RFI-shielding structure material is available in any shape and in a variety of sizes for use as wall-to-wall shielding. MSD-4 can also be used for discrete wraparound components to envelope sources of RFI emissions within a digital system. The material provides system protection in attenuating radiated electromagnetic interference between systems that originate this interference, as well as systems susceptible to such interference. MSD-4 shielding structures diminish the strength of radiated, extraneous noise, and each structure is custom configured to assure attenuation compatibility within any CB matrix. The structures may function as stand-alone shields or be designed into the matrix of the manufacturer's membrane touch switch. Topflight Corp., P.O. Box 2847, York, PA 17404. (800/233-9836)



Form-in-place gasket

A form-in-place EMI gasket is a silicone elastomer filled with a silver-plated copper conductive particle that cures to create a flexible EMI shield and environmental seal. The gasketing is applied on a one- or two-dimensional plane to metal or plastic housings by means of a computer-controlled process that precisely dispenses the material onto flanges as narrow as 0.030 in. It eliminates the expensive tooling costs associated with molded conductive-elastomer designs. Shielding effectiveness is 75 dB at 10 MHz. Tecknit, 129 Dermody St., Cranford, NJ 07016. (908/272-5500)



RFI/EMI environmental seal

A double-bulb elastomer shielding gasket ensures protection from moisture and outside contaminants for electronic enclosures. The tandem conductive portion is a highly conductive coextruded outer layer that provides over 100 dB of shielding effectiveness up to 1 GHz. Vanguard Products Corp., 87 Newton Rd., Danbury, CT 06810. (203/744-7265)



Optical filters

H-100 thermosetting polyester and H-911 allyl diglycol carbonate EMI/RFI optical filters are chemical- and scratch-resistant plastics with excellent optical qualities. The optional low-reflectance surface finish on the filters is cast into the material so that it can't be rubbed or cleaned off. Both plastics are available in a wide variety of thicknesses. The H-100 filters can be custom color-matched to reduce color change due to EMI/RFI coatings. Homalite, 11 Brookside Dr., Wilmington, DE 19804. (800/346-7802)


EMI shielding products

A company's EMI shielding products are made from highly conductive claddings, resilient urethane foam, structural laminates, and corrosion-resistant coatings. The company's full line of EMI products are designed to meet the needs of engineers and designers in the medical electronics industry. Products include gaskets, laminates, envelopes, and fabric tapes. Schlegel Corp., 1555 Jefferson Rd., Rochester, NY 14623. (800/204-0863)



Photochemically etched shielding

A line of photochemically etched EMI/RFI shielding and filter screens protect components and provide electrical grounding. The shields are hand formed and can be custom designed to meet the most stringent customer requirements. Also available are custom bend lines, logos, soldered or welded corners, and RF cans with removable top covers. The manufacturer provides a broad variety of standard shielding materials and metals, including stainless steel, brass, and copper. In stock are over 2000 material part numbers in thicknesses from 0.0003 to 0.90 in. Photofabrication Engineering Inc., 500 Fortune Dr., Milford, MA 01757. (508/478-2025)



Plated nylon gaskets

Self-terminating plated nylon-yarn-over-foam EMI gaskets provide minimum shielding effectiveness of 90 dB at 500 MHz to 10 GHz. Soft Knit gaskets feature closely stitched covers knit of metallized nylon yarn over UL 90 V-0­compliant neoprene sponge elastomer. With 95% minimum coverage, the low-closure-force gaskets provide optimum contact for an effective radiation barrier, which results in shielding effectiveness. Instrument Specialties Company, Inc., P.O. Box A, Delaware Water Gap, PA 18327. (717/424-8510)



Custom composite gaskets

Custom composite EMI/RFI, EMP, and environmental assembled gaskets are produced with a die-cutting method that allows the manufacturer to produce various gasket sizes with minimal tooling and material waste. The gaskets are produced by die-cutting four rubber strips and assembling and bonding them with a rubber adhesive, thereby eliminating the material waste that is to be expected from die-cutting a rectangular shape with a large center cutout. These gaskets work well under low closure force and with uneven flange surfaces. A Monel wire provides the EMI/RFI and EMP seal, and a sponge rubber provides the environmental seal. PressCut Industries, 2828 Nagle St., Dallas, TX 75220. (800/442-4924)



Ferrite RFI/EMI suppressors

A general-purpose ferrite formulation is available in a wide range of sizes for suppression of interference frequencies up to 1 GHz. Cable widths up to 64 conductors can be accommodated with adhesive or mechanical mounting options for any surface. Extrawide styles permit double looping through the same openings for intensifying the impedance in a frequency range around 100 MHz. Data signals are allowed to pass unimpeded as the higher-frequency energy is dissipated. FerriShield Inc., 350 Fifth Ave., Ste. 7505, New York, NY 10118. (212/268-4020)



EMI gaskets

EMI gaskets, featuring a conductive jacket-over-urethane-foam design, meet the stringent shielding and mechanical performance requirements of today's electronic enclosures. Soft-Shield 5000 self-terminating gaskets provide greater than 90 dB EMI shielding from 30 MHz to 1 GHz and greater than 75 dB at 10 GHz. Closure force and compression/deflection characteristics are less than 1 lb/in. The gaskets are available with a pressure-sensitive adhesive tape for easy attachment. Chomerics, 77 Dragon Ct., Woburn, MA 01888. (617/935-4850)



Special-purpose filters

Special-purpose contrast enhancement filters can be designed to incorporate EMI/RFI and ESD protection to help equipment manufacturers meet regulatory requirements. Duralan II filters can incorporate various conductive materials that can either absorb and ground or reflect radiated electronic noise. EMI/RFI protection can be achieved at various frequencies from 10 MHz to 15 GHz, depending on design options. The filters are suitable for use with most active and passive displays. They can also include polarizers, security louvers, and other specialty materials. Silver Cloud Manufacturing, 525 Orange St., Millville, NJ 08332. (609/825-8900)



Custom converting

A company offers various shielding options to reduce or eliminate EMI/RFI and electrostatic discharge from electronic components. As custom converters, the company works from customers' blueprints or with their engineers to develop shielding methods that best fit their requirements and manufacturing constraints. The company will also supply sample materials or prepare prototypes for testing in customer components and/or component assembly equipment. GM Nameplate, 2040 15th Ave. W., Seattle, WA 98119. (800/366-7668)

Return to the MPMN home page

High-Speed Injection Molding of Thin-Wall Polycarbonate Tubes

Medical Plastics and Biomaterials Magazine | MPB Article Index

Originally published July1997

TECHNICAL PAPER SERIES

Demands for low cost, light weight, and miniaturization, along with restrictive engineering parameters, have forced many medical device designs into product envelopes that push the limits of moldability. For example, in endoscopic surgery, thinner-wall cannulae (tubes) are now being required. Such designs can tax the flow characteristics of the polycarbonates typically specified. When we decided to develop a 100-mm-long tube with ribs and 0.68-mm-thick walls, mold-flow analysis predicted a cycle with injection pressure of 23,000 psi and melt temperatures of 323°C. Previous work indicated that molding polycarbonate tubes at these conditions results in degradation of the molecular weight of the polymer. Although in that case the molecular-weight damage was not enough to significantly reduce the polymer's mechanical properties, it was demonstrated that processing polycarbonate at 323°C significantly limits allowable residence time of the polymer in the barrel and narrows the permissible processing condition window.

Molding thin-wall polycarbonate tubes on conventional injection molding machines with maximum injection pressures of 138­158 MPa results in molecular-weight degradation of the polymer because of the requirement for excessive melt temperatures. In light of this fact, we began to investigate the effects of high injection speed and pressure on our ability to fill a 100-mm, 0.68-mm wall cannula while protecting the polycarbonate construction material from loss of molecular weight.

EXPERIMENTAL CONDITIONS, RESULTS, AND DISCUSSION

Procedural details and results are discussed below for both preliminary experiments and follow-up studies. Analysis of these findings led us to formulate final conclusions and thus determine a successful manufacturing strategy.

Injection molding trials were conducted on various injection molding presses with accumulator-assisted injection control. Each machine is described more fully within the discussion of the experiment in which it was used. The melt temperatures listed were actually measured with a pyrometer on polymer melt extruded from the nozzle under low-shear conditions. In all the following experimental work the polycarbonate material used was Dow 2081-15 (melt index =15 g/10 min).

Preliminary Experiment. First, to study the effects of injection speed on the ability to fill a 100-mm cannula with a thicker wall (0.76 mm), injection speeds were gradually increased while a constant melt temperature of 296°C was maintained on a Sumitomo SG 125, a 125-tn, 122-g machine. At speeds between 200 and 300 mm/sec, a completely filled, stress-free tube could not be manufactured. It was found that in the 300­375-mm/sec range, an acceptable tube could be molded. At a speed of 375 mm/sec, injection pressure was 83 MPa. Measurement of molecular weight of the material in the molded tubes showed that no degradation during molding had occurred.

Based on these results, it was theorized that high-speed shear is more effective in reversibly decreasing the viscosity of polycarbonate than is elevated melt temperature.

The results corroborated information reported by polycarbonate suppliers claiming that polycarbonate viscosity is dramatically affected by shear rates.1,2 As stated in one report, "The combination of injection speed and gate size allowed us to achieve the desired span of shear rates."1

Initial Thin-Wall Cannula Molding. A new cannula design mandated that the wall thickness of the tube be reduced to 0.63 mm. The most challenging design feature for the production of this cannula was the requirement for ribs on the outer diameter. The rib design featured a height of 0.25 mm, with a 0.05-mm radius at the tip.

In designing the molding tool and selecting the injection molding equipment for this project, two items were of prime importance. The injection molding equipment needed to be capable of achieving injection speeds up to 500 mm/sec, and venting of the tool was perceived to be critical.

The Nestal Series N 150-tn clamp injection molding press was at first selected for this job. This machine features a 225-g barrel with injection speeds up to 500 mm/sec and injection pressures up to 214 MPa. Tooling was designed with inserts in the sleeve area to provide for facile modifications. Because the optimum gate size was an unknown, an intermediate-size, 1.27-mm gate was chosen.

With an H-13 steel insert, a melt temperature of 315°C, and the machine operating at its maximum pressure, the cannulae molded were clear, the cobalt blue tint characteristic of the resin having disappeared. The rib section of the part was not filled or packed out completely. Attempts using vacuum assist did not improve the process, and it was concluded that any further work with H-13 inserts would be futile.

The H-13 inserts were then replaced with Porcerax II porous steel inserts in the sleeve area of the cavity. Satisfactory cannulae could then be produced at melt temperatures of 304°C, with an injection speed of 500 mm/sec and a resultant injection pressure of 158 MPa. The porous steel supplemented the venting, and both part quality and rib definition were significantly improved.

At this point, it was decided that the Nestal N series injection molding press was not capable of achieving the injection rates and pressures necessary to optimize the processing conditions, and a Nestal Synergy 150-tn injection molding press was subsequently selected for further work in this program. Fitted with a 85-g barrel, this press was capable of speeds up to 1000 mm/sec and pressures up to 207 MPa.

High-Speed Injection Experiment. In the next experiment a different five-stage injection profile was devised by trial and error for each polymer melt temperature at 5.5°C intervals between 287 and 315°C, inclusive. Each stage of each profile was set for a 0.1-second duration. Minimum injection speeds at each stage that were capable of producing visually acceptable parts were selected for the profiles. The stages of the profiles were scaled down from high speed to low speed to maximize the rheological effects of the high-speed injection while minimizing jetting of the melt in the cavity. The injection profiles that resulted from this exercise are shown in Table I.

Table I. Melt temperatures and injection-velocity profiles used in a high-speed injection experiment.

Under the conditions of the experiment, the injection pressure peaked at 220 MPa for 0.05 seconds and then subsequently dropped to approximately 138 MPa or slightly less for the higher temperatures tested, 304° to 315°C.

When molecular-weight studies were conducted on the molded cannulae, no molecular-weight degradation could be found for product molded at any of the melt temperatures. This result was especially significant in light of earlier studies on cannulae with 0.89-mm. walls and no ribs, molded at conventional injection speeds of 100 to 150 mm/sec through a 2.3-mm gate. These parts had displayed significant molecular-weight degradation probably due to the use of excessively high melt temperatures--approaching 337°C--to achieve fill.

Gate Effects. Subsequently the effect of gate size on the molding process was examined. When the 1.27-mm gate, used in the work described above, was increased to 1.52 mm, the required level of shear thinning of the polymer did not occur. With the larger gate, higher melt temperatures were required to fill the cannulae at each injection speed than with the 1.27-mm gate. When gate size was reduced to 1.02 mm, gate freeze-off occurred and prevented assessment of the effect of this orifice size on the polymer flow characteristics.

It has been stated that "thermoplastics are non-Newtonian in nature, which means that their viscosity will change dependent on their velocity; i.e., the amount of shear experienced. This non-Newtonian nature is key in thin-wall molding."2 So is the short-lived temperature increase in the polymer, which is believed to occur due to shear heating during the high-speed injection step. Together these effects provide the low polymer viscosity needed for full, stress-free parts to be produced. The results of the current study support the concept that polycarbonate can be injection molded at high speeds and shear rates if properly controlled. Material flow characteristics, gate position and size, and venting must all be balanced to obtain a structurally sound part.

For polycarbonates, the standard assumption that injection speeds should be below 250 mm/sec has been discredited. Rather, an intelligent application of shear effects can open up the possibility of molding long, thin walls without very high melt temperatures and the accompanying polymer degradation. To achieve success in such processing, the type of injection molding equipment is critical. The injection molding machine should be capable of minimum injection speeds of 500 mm/sec, and injection pressure must be greater than 207 MPa. Tooling should be designed for maximum venting, and gating should be in the direction of flow. Gates should be small enough to promote shear thinning and transitory heating of the polymer but not so small as to cause premature freeze-off.

CONCLUSION

The results of the numerous experiments described above support the belief that injection molding of thin-wall polycarbonate parts under high-shear-rate cavity filling and moderate (287°­ 315°C) melt temperature conditions provide superior parts with less molded-in stresses and polymer degradation than parts formed under conditions of lower shear and higher melt temperature. The shear regimen during filling of the cavity is conveniently controlled by injection speed and gate diameter. The ability to fill the part well under these conditions results from extreme thinning of the polymer, probably due to both its pseudoplastic nature and the short-lived temperature rise it experiences because of the shear energy imparted to it. While the short-lived elevated temperature of the polymer produced by the shear energy as the polymer passes rapidly through the restricted flow channels is effective in helping to thin the material, it is much less damaging to it than a high temperature (315°­343°C) experienced by a resin throughout its residence interval in the barrel. High-speed, high-shear, moderate-melt-temperature injection regimes are recommended for the production of high-quality polycarbonate medical device parts.

REFERENCES

1. Serrano M, Little J, and Chilcoat T, "Critical Shear Rate for the Injection Molding of Polycarbonate, Polystyrene, and Styrene Acrylonitrile," in Society of Plastics Engineers, Inc., Technical Papers, vol XLI (ANTEC 95), Brookfield, CT, SPE, pp 357­365, 1995.

2. Fassett J, "Thin-Wall Molding: Differences in Processing over Standard Injection Molding," in Society of Plastics Engineers, Inc., Technical Papers, vol XLI (ANTEC 95), Brookfield, CT, SPE, pp 430­433, 1995.

Robert T. Alvarez is a plastics consulting engineer for Ethicon Endo-Surgery, a Johnson & Johnson Co. (Cincinnati). He holds a degree in plastics engineering from the University of Massachusetts Lowell, and has more than 30 years' experience in polymer processing and design. Jorge Gutierrez, also at Ethicon Endo-Surgery, is a staff development engineer with 16 years' experience in the biomedical field. He holds a degree in mechanical engineering from Georgia Tech University, and has worked in various roles in manufacturing and product development. Mac Russelburg is project manager at Tech Group Tempe (Tempe, AZ). He has been involved in injection mold making for plastics for approximately 18 years and also has extensive experience in processing technology.


Copyright ©1997 Medical Device & Diagnostic Industry

MEDICAL TECHNOPHOBIA

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI July 1997 Column

EDITOR'S PAGE

Medical technology can and should be a key component of a resized, consumer-oriented, and cost-effective health-care system.

Old orthodoxies die hard, it seems. Listening to a National Public Radio news program recently, I heard a typically well-reported story on the latest trend in HMOs: allowing customers to go directly to medical specialists, bypassing the general-physician gatekeeper. This trend is made possible, the reporter noted, because "medical inflation has slowed much more dramatically than analysts expected," so that HMOs are willing to pay for more choice. But an expert interviewed noted that the trend could be short-lived. "He predicts," the reporter said without further comment, "that medical inflation will start rising again, driven by an aging population and costly technology."

This observation was almost a throw-away line, but it unsettled me nonetheless. Will the experts ever abandon this obvious misconception about medical technology? Do they all believe it?

Fortunately, an antidote to this medical technophobia was at hand in a new book, Market-Driven Health Care (Addison-Wesley) by Harvard Business School professor Regina Herzlinger. In it, I found confirmation that this belief about medical technology is indeed widespread: "Most health policy experts," she writes, "firmly believe that medical technologies are the root cause of excessive health-care costs." Some even argue, she adds, "that medical technology innovations are so inherently cost-increasing that they will cause health-care costs to continue climbing even after all the waste and inefficiency has been wrung out of the system."

Herzlinger firmly believes otherwise. Many new medical technologies, she says, have reduced health-care costs, but "have been so pervasively purchased by health-care institutions--some of which use them very little--that they have increased costs as well." Moreover, she claims, the many analyses that purport to show how technologies have increased costs in fact show only that prices have increased--a result of a health-care system that has not until recently competed on price.

Indeed, Herzlinger argues that medical technology can and should be a key component of a resized, consumer-oriented, and cost-effective health-care system. The new model for this system is what she calls a "focused factory," a health-care provider specializing on a specific disease. An example is Denton Cooley's Texas Heart Institute, which she says provides bypass operations for about $27,000, some $16,000 less than the national average. One of the keys to this success, evidently, is technology. As Herzlinger puts it, "the august surgeon proudly notes that he substituted a $10 plastic disposable tube for one usually costing $75, with no loss in quality."

Herzlinger's book should be of particular interest, by the way, to small manufacturers. As she pointed out in a phone call, she believes that large, vertically integrated health-care systems, which have tended to ignore smaller device companies, have no future. "Vertically integrated systems," she said, "cannot compete against smaller, focused-factory health-care providers." Manufacturers that develop cost-effective products suited to disease management approaches should do well in the future, regardless of their size.

What seems to set Herzlinger apart from other health-care policy experts is her ease with technology. When I asked her what motivated her to write the book, she told me that it began with a series of articles for the Harvard Business Review called "Can We Control Health-Care Costs?"

"I decided the answer was yes," she said, "but not through saying no to customers, or rationing health care, or building big systems. I saw another way, through entrepreneurs, and I understood that technology was a positive, not a negative."

Doubtless, few readers of MD&DI suffer from fear of technology. But to help them fend off the technophobes, I recommend a dose of Professor Herzlinger's book.

John Bethune

[email protected]


Copyright ©1997 Medical Device & Diagnostic Industry

HIGH-QUALITY CARE at Low Cost

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI July 1997 Column

The president of Sabratek Corp. (Niles, IL) urges the use of new systems and approaches to respond to changes in the health-care industry.

Recent health-care cost containment has created dramatic changes in health care, leading to paradigm shifts in the whole industry. It is now widely recognized that the delivery of health care is more cost-effective when it is provided outside a traditional hospital environment. Alternate site care (ASC) settings include subacute facilities, outpatient clinics, skilled nursing homes, physician offices, and patient homes. Evidence indicates that care in familiar settings such as the home results not only in lowered costs, but in improved patient outcomes as well.

This paradigm shift has accelerated with the advent of managed care, creating a major growth opportunity for the ASC market. This is substantiated by the fact that patient populations in ASC settings continue to grow. For example, from 1995 to 2000, infusion therapy patients in this market will increase by 50%, the most significant growth coming from pain management, chemotherapy, and antibiotic therapies (see Table I).

For the ASC industry to continue to realize such growth, providers must not only continue to lower costs but also maintain or enhance quality. Technology is one answer as long as it is not technology for technology's sake. In addition, understanding cost structures should allow health-care providers and manufacturers to leverage costs and enhance quality.

It is also clear that telecommunication and computers will play a much greater role in the health-care industry than they have up to this point. Integrating these technologies has essentially created a new industry--telemedicine. This rapidly emerging field combines advances in telecommunications, computer science, and medicine to enable health-care providers to diagnose patients at one location and then treat them at a remote location. The key to continued rapid expansion of telemedicine depends on its user-friendliness and on a smooth transition from traditional practices by both clinicians and patients.

In addition to health-care providers, manufacturers play a key role in adapting to these shifts. Manufacturers must supply products that meet the needs of this new health-care environment. This requires forming partnerships with health-care providers to develop open relationships and to fully understand providers' performance and cost requirements. Manufacturers must translate this information into new designs and maybe even new manufacturing processes to create products that meet health-care providers' needs for high quality at low cost. These requirements entail developing products that are suitable for all health-care environments and that are easy to use by both clinicians and patients. Equipment for telemedicine must easily adapt to traditional health-care practices to ensure the success of this technology.

When practitioners choose devices and software packages for telemedicine, they may be tempted to look only at the up-front acquisition cost. If quality of care is to be ensured, however, the overall cost of providing care to the patient must be the prime consideration for the selection process. An in-depth evaluation of each facility must be performed to adequately assess the overall cost/benefit relationship for selection of a suitable system. In addition, with the increasing seriousness of the conditions of patients in ASC surroundings, a careful assessment of patient needs and comfort will enable providers to use the most flexible and cost-effective system without compromising quality of care.

Such a system should provide a continuum of care for each stage, from confined therapy to ambulatory care, and could add significant value to the ultimate therapeutic outcome. For example, as providers standardize devices, choosing a system that is simple and intuitive to program and use will reduce both nurse and patient training time and increase a user's comfort level. In other words, health-care providers will need access to systems that are flexible enough to move effortlessly among all health-care environments so that they can offer consistently high-quality care at low cost.


Table I. Total ASC infusion therapy patients by therapy type in 1995 and projected for 2000, along with the percentage change.

When choosing devices and systems that fill this need, providers will consider the cost equation. Fixed costs include equipment and inventory for superior asset management, technology obsolescence, durability, and reliability. Variable costs include disposables and labor. Labor costs include the time it will take for training, clinician/patient interaction, pharmacist or technician time for setting up a system, and service and repairs. Indirect costs include infections, missed or delayed therapies, and clinician intervention time.

Another way to look at the cost for such systems is to weigh soft costs versus hard costs. Soft costs include nurse intervention time, nurse travel time, nurse training time, documentation, patient training time, and patient monitoring. Hard costs include primarily equipment and disposables costs. A conservative estimate is that about one-third of total expenditure is for hard costs.

Selecting a suitable hardware and software system can dramatically reduce soft costs. For example, if clinician intervention is required, telemedicine can enable the nurse or physician to provide quality care from a remote site, thereby lowering costs such as travel. A user-friendly remote communication system that can work with several device types and can transmit voice and data simultaneously allows clinicians to communicate with the device and patient without requiring the patient to either stop the therapy or hang up the phone. This powerful combination of medical devices and communications technology enables providers to collect real-time data for outcome studies, as well as reduce intervention time by eliminating unnecessary travel.

With such paradigm shifts taking place in the health-care industry worldwide, developing devices to serve the ASC industry provides an unprecedented opportunity for growth. This industry will need new systems and approaches. This transformation is already taking place in the health-care industry. Today's leading manufacturers may become tomorrow's followers if they don't look at cost and quality using a new paradigm.


Copyright ©1997 Medical Device & Diagnostic Industry

Reducing Development Timewith Requirements Management

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI July 1997 Column

DESIGNER'S TOOLBOX

A requirements management system enables engineers to track the functions, behaviors, and performance of a design's specifications.

A requirements management system (RMS) is the primary tool for defining what a device must do. Properly executed, such a system, which usually consists of a computer and a database, can reduce development time and cost. Because it provides validated specifications, an RMS reduces design iterations.


Figure 1. A general block diagram of a typical system.

An RMS captures requirements from all sources for all aspects of the product. It also allows multiple levels of abstraction, from a black box (understanding only what goes in and what comes out), to a gray box (understanding the product's functions and behaviors), to a white box (understanding exactly how the product is made). Such a tool allows designers to partition and allocate requirements to the desired level of abstraction, and provides traceability of each requirement. An RMS also controls key interfaces that evolve from partitioning the requirements. The system uses analysis and simulation tools to provide requirements validation, and can generate black-, gray-, or white-level specifications. An RMS can provide a matrix indicating compliance with verification and validation activities and generate management data on the requirements process.

RMS REQUIREMENTS

An RMS can define product requirements in terms of function (what is required), behavior (how it is achieved), or performance (how well it is achieved--usually a numerical value). The system should define requirements in engineering terms that result in process (function), logic (behavior), and capability (performance) equations. For this process, high-level user or marketing requirements must be translated into quantifiable engineering design requirements that can be incorporated into the design.

Analysis and Simulation. An RMS should evaluate and validate requirements through the use of mathematical models of them. It should contain a simulation engine to simulate function and behavior equations. A performance-modeling engine enables the system to evaluate tolerance bands against requirements. Sensitivity studies and Monte Carlo simulations, which estimate variations by selecting random distributions, help engineers partition and allocate requirements to compensate for manufacturing variations and variations in the environment over the life of the equipment. An ideal RMS has built into it--or has an interface to--a safety analysis engine for hazard analysis, failure mode and effects analysis (FMEA), and fault tree analysis.

Verification and Validation. The system should draw information from the database of requirements to generate a compliance matrix that indicates that all requirements are verified at least once in the development process. Along with the prototype construction schedule, this matrix enables engineers to efficiently plan and execute verification of engineering requirements.

Management Functions. An RMS should provide a view of the management and regulatory requirements to enable engineers to assess the status of the requirements generation and verification process, ensure a successful transfer of the requirements to manufacturing (design transfer), and provide a log of the requirements process for the device's design history file.

Interfaces. Ideally the system should interface with other systems in the development process. The RMS should be linked directly to design output. This internal design or engineering group is the primary recipient of RMS-generated data. The system should also be linked to a project management system to enable a project manager to allocate resources, and to a document control system to track controlled copies of the specifications. Linking these systems enables design reviews to be a routine part of the review process. This provides engineers and designers with a tool to incorporate, control, and track crucial requirements into the design of a product.

Edward V. LaBudde is managing director of LaBudde Systems (Westlake Village, CA).


Copyright ©1997 Medical Device & Diagnostic Industry

FDA Invites Industry to Accept a Faster Alternative to PMAs

Medical Device & Diagnostic Industry Magazine
MDDI Article Index

An MD&DI July 1997 Column

WASHINGTON WRAP-UP

To speed product approvals, FDA is reviving an inactive statute that gets the agency involved early during product development.

James G. Dickinson

Reviving a statutory provision that had lain dormant for 20 years, FDA is inviting device innovators to submit early-stage product development protocols (PDPs) instead of premarket approval (PMA) applications for a promised final marketing clearance within 120 days.

The elements of a PDP became law in the 1976 Medical Device Amendments, but were not touched by FDA until this April when Center for Devices and Radiological Health (CDRH) director Bruce Burlington dusted them off and gave them to veteran reviewer Lillian L. Yin, director of the Division of Reproductive, Abdominal, Ear, Nose and Throat, and Radiological Devices, and to colleagues Ed Mueller of the Office of Science and Technology and James Norman of the Office of Management Services.

They in turn placed a PDP proposal on the Internet the same month. It included the statutory language and the accompanying congressional committee report from 1976. "The PDP process will be designed to include multiple methods of achieving its requirement," Yin, Mueller, and Norman wrote. "Provision will be made for 'real-time' reviews, on-site reviews, and other novel review mechanisms."

The PDP proposal is intended to:

"1. Provide a process that will allow FDA to effectively regulate Class III products from initial development to marketing to eventual replacement by more advanced products.

"2. Reduce the FDA resources required to review and approve new Class III devices.

"3. Reduce the total time to get a new Class III device to market.

"4. [Maintain] the overall assurance of safety and effectiveness as compared with the PMA process.

"The process will be designed to facilitate use of expertise outside FDA and will provide a clear development path 'road map' for products to the market."

The 1976 statute requires proposed PDPs to include descriptions of the device and any changes that may be made; any preclinical or clinical trials; manufacturing methods, facilities, and controls; and any applicable performance standards. It must also include proposed labeling; any other information "relevant to the subject matter of the protocol" that may be thought necessary by FDA (the appropriate advisory panel must concur on the need for this additional information); a requirement for progress reports to FDA; and, when completed, records of the trials conducted under the protocol.

FDA has 120 days to approve or reject a PDP. Marketing may not begin until, after approval, the sponsor submits a notice of completion explaining how the protocol has been fulfilled and setting forth the results of any required trials. FDA then has 90 days to accept or reject the notice.

In an interview, Yin said she is excited by this bold step, and looks forward to seeing the first company step forward to take advantage of it, perhaps in a pilot process that will serve as a guide for others.

The PDP process would replace the cumbersome and lengthy PMA process with a simpler, two-step process in which FDA will be involved at an earlier, pre­ investigational device exemption stage and remain involved through subsequent product modifications--an involvement that Yin hopes will expedite review of postmarketing supplements and perhaps eliminate the need for some supplements altogether.

She sees PDPs as eliminating "blind alleys" and unnecessary studies that can plague PMA reviews. Under the protocol, sponsors and FDA can agree in advance on what data are required, what end points are expected, and how future changes will be introduced. "Currently, a lot of companies come in missing this and missing that," Yin said. "This will save a lot of time."

Congress knows how to get FDA's attention: Pull on its purse strings. While there have been other attempts to change the way FDA operates (e.g., Vice President Al Gore's "Reinventing Government" initiative), congressional budget tightening has done more than anything else to radically alter the way the agency does business.

The most dramatic example of this to date came at the end of April when Bruce Burlington and Office of Compliance director Lillian Gill announced to their external advisory committee on medical device good manufacturing practices plans for a new risk-based program that would likely eliminate routine GMP inspections for most companies.

Historically, the Federal Food, Drug, and Cosmetic Act mandated that such inspections take place every two years, but Burlington and Gill were unabashed in acknowledging that lately the agency simply hasn't been able to come close to meeting that goal. Last year, it did better than most years, inspecting 53% of the device facilities scheduled for inspection. But FDA has been focusing most of its energies on preapproval, for-cause, and follow-up inspections regarding previous problems, and has tended to push routine GMP inspections onto the back burner.

Gill also discovered that of the 9000-odd device facilities registered in the United States for at least two years, 515 had never been inspected.

If the best that FDA can do is inspect half of what it's scheduled to, Burlington asked, "How should we set out to do the right half?"

Gill's answer was a risk-based compliance program, which would direct CDRH's 57 field device inspectors to visit the manufacturers of the riskiest devices and leave almost uninspected those who produce the least risky (unless unforeseen problems were to arise).

Using medical device reporting (MDR) data and device recall statistics from the last five years, CDRH's Office of Science and Technology assigned scores of 0 to 100 to each device type, with 100 representing a top inspection priority.

The 49-page list, known as the Compliance Policy Model, started with the highest-priority devices ranked in the high 90s. These included intravascular administration sets and diagnostic catheters, low-energy dc defibrillators and infusion pumps, continuous ventilators, apnea detectors, and implantable pacemaker pulse-generators. It worked down to such products as sterilizer baths, skin-graft guards, and periodontal test kits.

The advisory panel quickly picked the list apart, citing numerous inappropriate items. Committee chairman Ronald Zabransky, chief of microbiology at the Department of Veterans Affairs in Cleveland, fought to control the eruption of objections from his colleagues. Noting that although he himself had "found one which [he] thought was ridiculous," he would not allow the proceedings to erupt into unproductive arguments over specific examples.

Burlington and Gill quickly summoned the list's author, research biologist Stephen Sykes, who explained the numerical methods used and readily acknowledged instances of "imperfect" numerical sources. However, he insisted, if used only to establish compliance "bins" for determining priorities, his list was a useful tool and, indeed, the only available one.

Gill proposed to construct three bins of prioritized devices: those ranked 70 or higher, those ranked 40 to 69, and those ranked 0 to 39.

To spend FDA's dwindling enforcement resources on areas that best protect public health, Gill proposed to focus her office's activities on those in the 70-plus bin with scores higher than 90, and to prioritize remaining resources on the others in descending order.

The 20 devices with scores higher than 90 would be evaluated by a multidisciplinary CDRH team, who would review MDR and recall profiles, examine individual reports, and use team members' expert knowledge of the products and new technologies in the devices to develop strategies for problem evaluation and resolution.

For the remainder of the prioritized devices, Gill proposed scheduling half of the 70-plus Class III and Class II/Tier 3 devices for comprehensive inspections (i.e., examination of manufacturing specifications and procedures, reprocessing of devices or components, finished-device inspection procedures, device master records and device history records, complaint files, organization, environmental controls, cleaning and sanitation, equipment, labeling, distribution, and personnel). A complete inspection usually takes about 70 hours, and will take about 90 hours when FDA's new design controls take effect.

For Class II and Class I devices ranked above 70, she proposed "limited" inspections (i.e., examination of complaint-handling systems, MDR and device tracking, failure investigations, audits, in-process and finished-device rejects, procedures for change control, validation, and components) for 35% of registered facilities. Limited inspections were also proposed for half of the 40-plus Class III and Class II/Tier 3 devices, 35% of the 40-plus other Class II devices, and 15% of the 40-plus Class I devices. Gill proposed no routine GMP inspections for any devices ranked 0 to 39.

In discussing these ideas, the advisory committee agreed that CDRH was on the right track and had made a good start. But, after listening to industry critics, the committee questioned the accuracy of the MDR database and the reliability of the recall database--the entire foundation for Sykes's list.

Members balked at the idea that, using CDRH's proposed strategy, one firm's problems with a device could taint an entire category of similar devices and place it unfairly in a high-priority inspection zone, possibly subjecting innocent firms to unnecessary comprehensive inspections. FDA should develop a way of assessing an individual firm's compliance history, rather than depending on potentially faulty statistics about device categories.

The advisory committee members were also uncomfortable with the distinction between limited and comprehensive inspections.

And lest anyone think that the proposal was anything new, Medtronic's legal counsel, Robert Klepinski, asserted that his pacemaker firm was already experiencing multiple comprehensive inspections because it had five pending PMAs at CDRH. The proposal merely solidifies what FDA is already doing, he alleged. Despite protestations by FDA officials who work inside the Washington Beltway that the infamous "gotcha" syndrome is a thing of the past, it actually is alive and well in the field, Klepinski complained.

Gill denied that her proposals are not new, and suggested that Klepinski may have confused multiple PMA­related inspections with routine GMP inspections.

Clearly, it's back to the drawing board for Gill; the advisory committee gave her a lot to work with.

One thing is certain, however. Something closely resembling her concept is coming soon to an FDA office near you--fiscal reality mandates it.

James G. Dickinson is a veteran reporter on regulatory affairs in the medical device industry.


Copyright ©1997 Medical Device & Diagnostic Industry