On pins and needles: The evolution of a suture tray

Anne Marie Mohan

January 29, 2014

18 Min Read
On pins and needles: The evolution of a suture tray

As company lore tells it, the original design for the first injection-molded plastic tray for surgical sutures was born on a dinner napkin, sketched by Robert Cerwin, engineering fellow, Advanced Packaging Development for medical device manufacturer ETHICON Products, a division of ETHICON, INC., a Johnson & Johnson Company. While the truth may reveal that a bit more research and development effort was involved in bringing forth that initial concept, the fact remains that Cerwin, along with a team of packaging engineers, completely changed the suture market's primary system of packaging and delivery with a fairly simple, yet ultimately radical, prototype.

Another interesting, and true, story surrounding the origins of what was to become the ETHICON Product door-style RELAY?* Suture Package tray, is that when Cerwin brought the prototype in for mold-flow analysis, and when he brought it to potential suppliers of the injection-molded piece, he was told that the piece could not be molded due to its close tolerances. "We went to the injection molders," Cerwin recalls, "but they didn't want to spend the development money. They didn't think that ETHICON Products would go through with it."

One supplier, Unimark Plastics (www.unimarkplastics.com) of Greer, SC, eager to expand its medical business, undertook the challenge, however, and today, close to 2 billion of the suture trays have been molded (see complementary article, Stack molding breaks technology barriers, beginning on p. 62 of this issue).

Through several generations, the tray has evolved from a one-piece design that is wound semi-automatically with suture threads to a two-piece unit that allows for almost complete packaging line automation, with a lower cost per piece and enhanced tray properties.

Employing roughly 100,000 people worldwide in its more than 200 companies, Johnson & Johnson is arguably one of the most well known names in healthcare products. From pharmaceuticals and medical devices to OTC consumer medications and personal care items, the company has grown almost exponentially since its incorporation in 1887. In that year, Johnson & Johnson brought to the healthcare arena the first sterile wound care management products, including sterile surgical dressings and absorbent and antiseptic ligatures.

"The history of Johnson & Johnson is built on sterilization competencies," says Scott Otto, manager, packaging development for ETHICON Products. "We were the first to do a lot of things with various forms of sterilization, starting with steam heating and eventually getting into chemicals, such as ETO [ethylene oxide], and then cobalt 60 [gamma]."

In 1949, ETHICON, INC. was formally established as a separate division of Johnson & Johnson in Somerville, NJ, and began to diversify its product line to meet the growing demands and new challenges resulting from increased specialization in surgery. The company's suture line expanded to include natural fibers beyond catgut and silk to cotton and linen, and then into absorbable and nonabsorbable synthetic fibers and stainless-steel and tantalum needles.

Beginning in the early 1990s, ETHICON Products acquired other, complementary companies, specializing in wound care management, gynecological surgical devices and devices used for cardiovascular surgery. Functioning independently from these divisions, ETHICON Products Worldwide operates 10 standalone manufacturing facilities throughout the world, as well as several global distribution facilities, that together handle more than 4,000 stockkeeping units. Its vast array of suture products today represents more than 70 percent of all sutures sold in the world. In the U.S., the market share of ETHICON overall is approximately 80 percent.

In the late 1980s, with its reach expanding across the globe "like a very big octopus with unlimited arms," as Clifford Dey, the principle engineer at ETHICON Products describes it, Johnson & Johnson began pursuing globalization strategies to leverage its buying power, standardize its operations and nurture collaboration between its companies. As part of this effort, ETHICON Products began looking at ways to bring its 10 production facilities into harmony for maximum efficiency.

"ETHICON, being around as long as it had, was like a microcosm of Johnson & Johnson," says Otto. "Each plant was operating on its own, no matter where it was located, with its own methods of doing things. There was a lot of competition between facilities, and in many cases, a lot of redundant efforts were being made."

One of the areas explored by ETHICON Products was a change in its existing suture packaging, which consisted of a paper folder held in a foil packet and then a peelable pouch constructed of DuPont (www.medicalpackaging.dupont.com) Tyvek?/polyethylene/foil. Having continuously evolved since the late 1800s from a glass vial held in a jar filled with sterilant fluid, the paper tray was a vast improvement over preceding technologies, but the ETHICON Products engineering team still saw opportunities for greater user-friendliness in the field.

With the help of the ETHICON Products machine shop, Bob Cerwin had a mock-up of a two-piece tray made using polyvinyl chloride, with a bit of foam material used to hold the needle. One of the advantages of the new design was this needle park, which held the suture needle firmly in place, ensuring that it would be in the same location every time in every package. This was a huge benefit to the surgical environment, where the risk of the transmission of AIDs, STDs and other blood-born viruses via needle-sticks had become very grave. It also eliminated the chance that the needle would puncture the foil overwrap and threaten product sterility. In addition, the new design also provided greater "suture memory," meaning that it gave the suture less of a set and allowed it to unwind from the tray straighter than when it was manually wound into the paper folder. The tray was also less expensive than the paper tray, and it was recyclable?a real bonus in environmentally conscious early '90s.

Although reaction to the prototype tray from focus groups and marketing research was extremely positive, Cerwin recalls that ETHICON Products' management gave its approval for development of the new design only reservedly because it represented such a big change. It was at this point that fate stepped in, or "Cerwin-dipity," as Bob Cerwin's colleagues refer to it: Another company tried to challenge the ETHICON 80-percent share of the U.S. suture market. "All of a sudden, I had this project that was not only trying to deal with harmonization," says Cerwin, "but I had a competitive threat."

The Door RELAY? package was introduced in 1991, through intense collaboration between ETHICON Products and Unimark. Measuring just under 31/2 in. long and 11/4 in. wide, the thin polypropylene device was produced as a one-piece tray, with tabs around the outside that could be folded down after suture winding. The new tray's design allowed the sutures to be wound semi-automatically using a vacuum to positively place a suture in the tray, after which the tabs were closed to keep the suture from coming out.

The Door RELAY? package was just the beginning of a line of trays?including the Zipper 1 (Z1), the Z2 and the Z3?that, with each generation, accommodated a greater number of skus, as well as pushed Unimark's injection-molding capabilities to the next level and allowed for increased packaging automation at ETHICON Products. "We had the breakthrough development, and then a lot of what you would call continuous improvement, or evolution," says Cerwin.

Dey agrees: "As opposed to really changing, we evolved. In effect, it [the Z3] is a different package, but it's just an evolved package from where we were; it's the next logical step."

Beginning with the Z2, the ETHICON Products one-piece design became a two-piece part that was ultrasonically welded at Unimark's manufacturing facility. The tray enabled ETHICON Products to advance to the next level of automation in its winding facilities, where it began using stylus winding. "We emphasize that when we look at these designs, we see a precision part that's a part of an automated piece of equipment [stylus winder] and that, incidentally, becomes a part of the package," says Cerwin. "With the paper tray, you could almost divorce the design from the equipment. But you can't do that with the plastic trays."

ETHICON Products' sutures are wound and packaged in many plants across the globe. Each plant deals with several specific types of suture products, such as absorbables or nonabsorbables, monofilament or braided sutures, and gamma-radiation- or ETO-sterilized products.

Situated amidst the lush, tropical vegetation of the island of Puerto Rico, the ETHICON San Lorenzo plant packages nonabsorbable sutures. While most of these sutures are cobalt-sterilized, the PROLENE? polypropylene Suture line, designed for use in cardiovascular, ophthalmic and neurological procedures, is ETO-sterilized.

On a recent visit to the San Lorenzo facility, PD had the opportunity to observe all of the generations of suture-winding technology?from figure-eight winding of paper trays to the almost fully automatic packaging process for the Z3. According to Delfin A. Lorenzo, engineering technical leader for the plant, preparations are presently underway to phase out a large number of the paper trays, which will be replaced by Z3 trays that are wound in a slightly less automated process than is used for the majority of the Z3 trays. This phase, he says, addresses the smaller suture sizes, along with the double-arm codes, or those sutures with needles at both ends.

The last needles to convert from paper to plastic trays will be those that are too big to fit in the Z3, such as a 3-in. cord length needle. These will be accommodated by another tray design that Cerwin says will be introduced within a couple of years.

Presently, paper folders are still in use for these products, which are manually wound in a figure-eight winding process. "There is a lot of wrist movement with this type of winding," relates Lorenzo. "The operators have ergonomic breaks two times each shift."

After winding, the filled paper trays are packed in a preprinted tear-open foil lamination supplied by Alcan Packaging (www.alcanpackaging.com). The folders are heat-sealed in a foil pouch by a manually fed turntable machine designed by ETHICON Products. The foil overwrap contains information such as needle point size, suture size, product name and opening instructions, all of which are preprinted onto the foil either in-house in the facility's duplicating department using seven-color flexo presses from Mark Andy (www.comcointl.com) or by Perfecseal (www.perfecseal.com).

The foil pouch is then packed in a peelable thermoform pack that uses a bottom web of DuPont Tyvek 2FS? sealed to a top web of clear, coated polyolefin film supplied by Perfecseal.

The pouch is formed on one of six Multivac (www.multivac.com) rollstock machines of various models that have been manipulated by ETHICON Products to seal through the film, rather than the Tyvek, for what Cerwin says is "a consistently better package." When possible, the tear-open foil pouch is eliminated, and the sutures are wound onto paper folders preprinted by The John Henry Packaging Group Southwest (www.jhpackaging.com) that are then placed in the Tyvek/foil pouch.

In a final step before sterilization, Tyvek/film pouches receive a bar code, expiration date and lot number from an in-line Bell-Mark (www.bell-mark.com) thermal-transfer printer.

Moving from completely manual packaging to semi-automatic winding, the plant has eight stations at which operators wind sutures onto Door RELAY? packages and seven where the Z1 trays are wound. During this process, operators manually park the needles into the air-winding machine, which winds the suture onto the tray and then closes the tabs. The trays then receive a "lid" or a preprinted, die-cut paperboard label that is affixed to the tray at two tie points. The lidstock, printed on the Mark Andy presses, is a custom-made paperboard from Monadnock Paper Mills, Inc. (www.mpm.com).

Secondary packaging for the Door RELAY? package and Z1 products comprises a preprinted, peelable foil pouch from Amcor (www.amcor.com) for environmentally sensitive, or absorbable, sutures, or a Tyvek/film pouch for nonabsorbable products. To produce foil-wrapped trays, ETHICON Products uses custom form/fill/seal equipment from Harro H?fliger (www.hoefliger.de/), while the Multivac machines are used to package the nonabsorbables in Tyvek/film.

The culmination thus far of the ETHICON Products engineering team's efforts at global harmonization is represented by its most recent tray design and winding system: the Zipper 3, stylus-wound on custom-built machinery from Germany's Harro H?fliger. With the development of the two-piece Z2 in 1997, followed by the introduction of the two-piece Z3 in 2002, ETHICON Products added to its capabilities an almost fully automated system of suture winding.

While the Z2 design, made from high-density polyethylene, can only be used for the company's PROLENE? Suture line of nonabsorbable monofilament sutures, the Z3 is the company's first "universal" tray, engineered to hold the largest range of suture materials and thicknesses and accommodating 90 percent of the company's worldwide suture volume. Relates Delfin Lorenzo, "The Zipper 3 will eventually eliminate paper folders and the Door Relay, Zipper 1 and Zipper 2 trays."

To drastically improve the accuracy of needle placement into the tray and the speed of suture winding for the Z2 and Z3, ETHICON Products worked with Harro H?fliger, which developed a proprietary machine that nearly eliminates operator intervention and effectively doubles the output of filled trays to 60,000 trays/week compared to manually wound suture trays. The first machine went into production in July 2002, and today the plant is operating nine machines.

The process begins when an operator scans an order for a batch of suture trays into a PC-based system developed by ETHICON Products. This information, including batch length, needle size, suture length, etc., is automatically transferred to the operator's assigned machine, which is controlled by a Siemens (www.sea.siemens.com) PLC. Meanwhile, another operator who acts as a materials handler for all the stylus winders "floats" from one machine to the next, loading stacks of 360 trays, packed in paperboard sleeves by Unimark, into the machine as needed. Since PD's visit, one machine has been equipped with next-generation loading technology in the form of a carousel that holds up to six times as many trays to increase machine productivity and efficiency.

To begin the winding process, the operator sits at the front of the machine, or "cell," and feeds each needle into a shuttle clamp that moves it behind the machine's guarding, where it is delivered to a Mitsubishi (www.meau.com) articulated pick-and-place robot. At the same time, trays are fed into the machine onto a four-station turntable that indexes each tray to the location where the pick-and-place arm places the needle into the needle park. The tray is then positioned under a winding head, and the precision stylus descends, catches the suture and completes the winding process, with the specific number of turns dependent upon the length of the suture.

A pick-and-place arm then removes the filled tray from the turntable and moves it to a slide plate. While it is being transferred, the tray is inspected for the presence of the needle by a Banner (www.bannerengineering.com) PresencePLUS? pixel counting sensor. Trays then receive lids printed in-line using a TEC America (www.tectpd.com) thermal-transfer printer?a process unique to the Z3 stylus-winding system. Paperboard for the lids is Iggesund Paperboard's (www.iggesundpaper board.com) Invercote SBS. The lids are preprinted with the color coding used for each product line (violet for Coated VICRYL?* [polyglactin 910] Suture, blue for PROLENE? PP suture, etc.) and are die-cut and fan-folded.

Before being fed into the TEC printers, the labels are checked by a sensor from Keyence (www.keyence.com) to verify that their color-coding corresponds to the batch type being run. Before a batch begins running, graphics for the lids are downloaded to the printer, which prints the variable label information in black and white. For each tray, a printed lid is punched out of the web, lifted and placed onto the tray by vacuum cups, and is locked onto the tray.

Lidded trays are moved by pick-and-place to another area, where they are inspected by a vision sensor from Banner for suture presence. Acceptable packages are then transferred to the demagnetizer station from Harro Hofliger, after which they are loaded into a magazine in stacks for manual transfer out of the machine.

As with the Z2 trays, secondary packaging for the Z3 trays consists of either a peelable foil pouch or a Tyvek/film pouch.

In 2003, ETHICON Products Worldwide's achievements were acknowledged by parent company Johnson & Johnson, when it awarded the Zipper 3 suture tray with its PACE Award for Packaging Process. The PACE Award is issued once a year in different categories and recognizes the innovation, process excellence, business contribution and environmental impact of projects within the Johnson & Johnson companies. Says Cerwin, "The suture business is over 100 years old, and at the time we began the project, we owned an eighty-percent market share, so everybody could have just sat back on their laurels. One of the hardest things to do is justify change."

From the initial introduction of the ETHICON Products plastic suture tray through that tray's evolution to enable greater process and packaging efficiencies, as well as enhanced usability, the engineering team did indeed bring many tangible benefits to the company's bottom line. Among them, a 33-ton reduction in paper at the San Lorenzo plant by 2002; a $250,000-per-year savings from cost avoidance related to ergonomic issues; a $150,000-per-year savings with the elimination of many of the tear-open foil pouches; and, with in-line printing, a savings in space and a reduction in waste.

Another advantage of the tray, says Cerwin is that "while you're looking at packaging that appears to be far more sophisticated [than the paper tray], the cost of goods is lower with enhanced properties."

For the end user, the benefits accruing from the company's continuing technological advancements are virtually immeasurable. "There is a rhythm that comes into play between the scrub nurse and the surgeon," Cerwin relates. "Anything that disturbs that rhythm can create a problem. When we put the tray into a film pouch, there is an immediate verification that the needle is in the pouch. The tray also provides greater suture memory, so the package will almost self-dispense. This means fewer steps in the operating room, which means that the patient is under anesthesia less.

"Our job, in the end, is to help people. Our final customer, although we sell to hospitals, is the patient."

*Trademark of ETHICON, INC.

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