Delivery Systems Have Come a Long Way From Being a Basket

Cases, trays are integral components in themselves

Ursula Jones
Contributing Writer

Twenty years ago, a delivery system was little more than a simple wire basket that hospitals would fill with orthopedic instruments and send off to be sterilized. But that has changed. Today’s cases and trays are nearly as sophisticated as the instruments themselves, featuring high-tech designs, advanced materials and detailed graphics.

First and foremost, a delivery system must position the instruments in a way that ensures maximum exposure to the sterilizing agent without degrading over time.

But they must also provide adequate protection for the instruments, while at the same time conveying a positive image of the company’s brand. The trick is achieving all of these goals at the same time.

Weight Matters

Because the instruments and implants are typically constructed of stainless steel or other metals, the case portion of the system must be as light as possible. Ideally, all of the instruments will fit neatly into a single tray and still weigh less than 16 pounds.

But if the overall weight exceeds that, it may be better to divide the instrument set into multiple trays.

This Paragon Medical polymer delivery system is used for small joint surgery. Photo courtesy of Paragon Medical.

According to Jake Jenkins, project engineer at Stryker Orthopaedics in Mahwah, NJ, manufacturers must strike a balance between the weight and number of trays. Multiple trays make the product more cumbersome for the surgical team to work with, but a heavy tray can be difficult to carry. “You basically want as few trays as possible, as light as possible,” he said.

But not everyone has the same objective, according to Mike Librot, vice president of sales for Medin Corp., a contract delivery system manufacturer based in Passaic, NJ.

“The nurse who has to carry these cases wants something extremely light, but also wants everything in one compact case,” he said. “The sales representatives don’t care how heavy the cases are as long as they only have to make one trip from the car.  We look for the middle ground.”

Jim Spencer, president of Advantis Medical in Greenwood, IN said some hospitals prefer instrument sets weighing less than 20 pounds.  “Anything heavier can result in some problems. We try to recommend that the customer split the set.”

Spencer noted that that, ultimately, the customer will have to make a judgment call as to whether the convenience of having the set in one case is more important than the weight.

Metal: Material of Choice

One of the first steps in designing a delivery system is to determine the materials of which it will be made. Aluminum is by far the most commonly used material, primarily because it’s lightweight and relatively inexpensive.

But while aluminum’s popularity is likely to remain high for the foreseeable future, it’s not always the best choice.

For example, high-pH sterilization chemicals used in certain European hospitals can severely damage aluminum cases and trays. These chemicals—such as sodium hydroxide—are thought to prevent the transmission of Creutzfeldt-Jacob disease.

Instrument makers have several options for these applications. One is to use materials other than aluminum—such as stainless steel or Radel—that can withstand the more rigorous sterilization process. “Or you can use a combination of steel with plastic trays or nylon-coated aluminum,” says Advantis Medical’s Spencer. His company typically recommends a stainless-steel outer case fitted with Radel trays.

According to Spencer, however, this is not as big of a concern for instrument makers as in the past. He explained that most European hospitals have either limited the use of these caustic sterilization chemicals to certain types of instruments, or they’ve switched to extended heat cycles. They’ll sometimes even take the instruments out of an anodized aluminum case prior to sterilization.

Stainless steel has also been a popular choice, mainly because it’s strong and durable.

Its primary drawback, however, is its weight. “The biggest problem with stainless steel,” said Jerry Grieco, vice president of Jewel Precision in Cedar Grove, NJ, “is that it is approximately three times heavier than aluminum.” Because of this disadvantage, stainless steel is often limited to use in very lightweight instrument sets.

Another option is titanium, which is considerably lighter than stainless steel but is much more expensive. The use of titanium in delivery systems has been more common in Europe, but its popularity is waning. Most orthopedic companies are finding that titanium’s benefits don’t usually make up for the increased cost.

Polymers: Pros and Cons

Plastics such as Radel are also commonly used for cases and trays. The main benefit is that the resulting trays can be lighter in weight than their metal counterparts.

But plastic’s lower strength capacity tends to limits its use to smaller instrument sets, such as those used in spinal and trauma applications.

“Radel doesn’t hold heavy instruments well,” Stryker’s Jenkins said. “It doesn’t stack as well and it can fracture more easily.”

To make the case stronger, the plastic material must be made thicker, which can increase its weight significantly.

“Plastic is not always lighter than metal,” explained Medin’s Librot. “Sometimes the thick plastic can weigh as much, if not more, as its metal counterpart. Per unit, metal is much stronger.”

Ultimately it comes down to the weight vs. strength equation. “There’s a balance point where the cost of achieving lightness is far greater than the efficiency you get out of using that material,” concluded Librot.

Plastic cases and trays can also require an additional upfront investment.

“The initial cost for tooling tends to be higher for plastics,” noted David Ivanko, senior engineering manager for San Diego, CA-based NuVasive. Ivanko said his company tends to prefer aluminum cases with nylon-coated stainless brackets.

Another potential drawback for plastic is the possibility that the case may retain residual moisture after sterilization, also known as “wet-packing.” And once you have moisture in the sterilization tray, there’s a chance that the sterile barrier can be broken.

While this condensation is more likely to occur in a plastic system, the problem can be eliminated with proper design. “Wet-packing can be reduced if the holes are in the right place,” said Andy Miclot, senior VP of marketing and sales for Symmetry Medical, an orthopedic supplier based in Warsaw, IN.

Larry Walck, manager of business development and orthopedic markets at Mack Molding in Arlington, VT, agreed. “There are sterilization concerns with every material,” he said. “It’s really a matter of design.”

Walck added that his company can custom formulate polymers to eliminate the problems associated with sterilization. “Polymers are probably where we’re seeing our biggest potential,” he noted.

Best of Both Worlds?

Metal-plastic hybrids are some of the newer options available for use in delivery systems.

By combining the two materials, instrument makers can get the strength properties of metal with the low weight of polymers. Hybrid materials also offer expanded decorating options, which can help convey the manufacturer’s corporate identity.

In some hybrid cases, a plastic tray will be reinforced with steel brackets to increase its strength.

In others, an aluminum case will be combined with plastic inserts or brackets for instrument protection. “It all comes down to a weight vs. strength balance,” said Stryker’s Jenkins.

Medin Corp., for example, uses nylon-coated brackets and silicone extrusions to cushion metal instruments. Jewel Precision offers a patented system comprising a lightweight aluminum case or tray coated with a durable plastic polymer.

According to the company, the PlasTel material eliminates wet-packing and can also withstand the high-pH cleaners being used in Europe.

“It’s an anesthetic thing,” Grieco explained. “It gives you the look and feel of plastic but with the similar sterilization integrity as a metal case or tray.”

Other advantages include improved instrument protection and full-scale graphics of the instruments to aid in repacking the trays after use.

Instrument Protection

In addition to ensuring proper sterilization, delivery systems must also provide adequate protection for the instruments inside. At the same time, they must make the overall system easy to use. “You need adequate space around the instruments to ensure sterility,” Miclot said. “But you also want the instruments to be snug in the cavities so they don’t rattle around.”

Fabricated and fully assembled by Mack Molding, this surgical case and tray delivery system features overmolded soft-touch bumpers that eliminate sharp corners and act as shock absorbers for a drop-impact requirement. Photo courtesy of Mack Molding.

Case and tray manufacturers can design different types of cushioning options into their systems.

“We use nylon to coat brackets to cushion metal instruments, so they don’t get marred,” said Librot. “We also manufacture our own silicone extrusions for cushioning.”

According to Librot, very small instruments and implants present their own challenge. “The parts are just too small to use standard metal brackets,” he said, “so we’ve had to design milled plastic caddies to hold parts that are very small or have an odd shape, particularly in spinal products.”

Often, the instruments are arranged in their order of use, which helps to guide the surgical team during the operation.

Graphics can also be printed or laser-etched onto the trays, making identification and setup less time consuming and easier for the end-user. “It’s important to have clear graphics, so that it’s easy for the surgeon to follow the procedure and identify the instruments,” Miclot added.

A well-designed system will also make it easier for the hospital staff to repack the case or tray after use.

“The end result is to minimize the amount of work that hospitals have to do,” said Mack Molding’s Walck.

Brand Recognition

To most orthopedic companies, the aesthetics of their delivery systems are an important consideration.  They want their trays and cases to reflect the company’s overall image and to carry brand recognition throughout the OR and the hospital.  

“A lot of companies are using sterilization cases and trays as actual selling points for their systems,” said Jewel Precision’s Grieco. “Anybody can make a box, but sophisticated cases can help with the company’s overall marketing plan.”

Delivery system manufacturers will often work closely with the instrument maker’s marketing department to ensure that the company’s brand is accurately reflected on the cases and trays.

“The systems may not be the same size or shape, but thematically it’s the same look,” said Mack Molding’s Walck. “Now you now have a branding initiative going on inside the OR.”

Medin’s Librot agreed. “Because of the way we’re vertically integrated,” he explained, “we’re able to create looks for our customers that are a fundamental part of their branding initiative.” Options include the use of anodizing, nylon coatings and silicone, as well as ornate silk screening and complex laser etching.

“Ideally you’d like the hospital or surgeon to identify the particular brand of instrument,” Symmetry Medical’s Miclot noted.

On the other hand, the surgical staff using the instruments may never see the outside of the delivery system.  

“Our customers don’t see the tray too much,” explained Stryker’s Jenkins. “They’re usually carried into the OR wrapped in a towel and then the lid is placed on a shelf.”

Customized Solutions

Most orthopedic companies prefer to focus on what they do best: designing implants and instruments.

Therefore, the vast majority will let a contract manufacturer design and build their delivery systems for them.

Working with a contract manufacturer can eliminate the guesswork that can be involved as well as significantly shorten development time.

“The design, development and production process can be challenging for the orthopedic OEM customer, because it can be frustrating and difficult to get it done right and on time,” explained Advantis Medical’s Jim Spencer. “We have differentiated our company by making the process as easy and pain-free as possible.”

While most cases and trays are custom designed and built for each product, some instruments might benefit from a more modular system. Jewel Precision, for example, offers a system that allows users to build their own delivery system from a variety of different sized trays, cases and brackets.     

The components can be used independently or mated together to form larger systems. No tools are required. According to the company, the system is well suited for clinical trials or when the user doesn’t have time to wait for a custom system.

No matter which route they take, orthopedic instrument manufacturers know that a delivery system is much more than just a box; it is a critical component of the product itself. v

Ursula Jones is a freelance writer who resides in Burlington, VT. She specializes in the medical device, pharmaceutical and packaging industries.