Manufacturing a Guidewire (Mandrels, Tips and Coatings)

Guidewires are constructed of an inner core wire, which is sometimes called a mandrel, and an outer coil. Core wires are typically made out of Stainless Steel or Nitinol but Modern Grinding has worked with an endless amount of materials in guidewire research and lab settings. All else equal, stainless steel guidewires are stiffer than nitinol wires. Super-Elastic Nitinol (NiTi) material can help resist kinking and maintains its shape throughout a procedure. Guidewire diameters are manufactured to achieve an optimum level of flexibility, stiffness, or floppiness depending on vascular navigation needs.

Guidewire Tips

Normally the core wire of a guide wire does not extend all the way to the tip of the guidewire, instead we grind guidewires to a tip and then coils and coatings are used to extend the tip and maximize maneuverability. Modern Grinding works off of specifications to craft the tip of the outer coil of the guide wires into j-curved, angled, and straight tips. “Floppy” guidewire tips are adaptable and not designed to retain a formed shape.

Guidewire Coating

Guidewire outer coils may also be plated with a heavy metal such as gold or platinum. Beyond metal plating on guidewires, most have some form of antifriction coating. TFE coating has been shown to reduce the coefficient of friction for stainless steel wires to 1/2 the uncoated value, and a silicone coating can reduce it to 1/6 the uncoated value. Many newer wires are coated with a hydrophilic polymer similar to silicone. Guidewire coatings and plates that we have used include PTFE, Hydrophoilic, Pebax, TFE, Teflon, Radiopaque, Tungstun, Polyurethane and many others.

This blog post was adapted with content from – http://www.ctsnet.org/portals/endovascular/nutsbolts/article-3.html

Medical Device Supply Chain Challenges and Opportunities

Challenges
At Modern Grinding, we are constantly thinking about ways to better serve medical researchers, medical suppliers, veterinary suppliers and the general medical device supply chain. The biggest improvement we think that we can make is in decreasing lead times. When it comes to ordering raw wire materials we are at the mercy of suppliers for lead times. Unfortunately, in order to cater to our customers unique custom wire diameter needs, we are forced to order wires on demand.

General Supply Chain
The medical supply industry functions much differently than the manufacturing industry. In addition to understanding stringent government regulatory requirements and FDA-mandated current Good Manufacturing Practices(cGMP) designed to ensure products are safe, pure and effective, manufacturers must also bear the burden of understanding the complexities and rigors involved in moving their sensitive products through the supply chain. At Modern Grinding we know that in the medical industry time can mean lives and can also make a difference in whether start-up medical device companies are able to get the supply they need and get off the ground. Here is a great report on manufacturing supply chain metrics – http://supplychaininsights.com/supply-chain-metrics-that-matter-a-focus-on-medical-device-manufacturers/

Opportunities
We are researching news ways to store stock inventory which is ready to manufacture versus ordering wire each time we need it. We are looking for partners who understand the industry, and want to work together on improving lead times, efficiency and quality. 

One way that we can improve inventory lead times is by stocking standardized wire sizes and then grinding them down to the correct diameter upon order. As a grinder, this is an option although some of the surface properties of the wire are lost in the grind process.

Additionally we could partner or move closer to our wire distributers, but we have several different wire providers which would make this difficult. Modern Grinding has years of experience in medical manufacturing but we will also take a very technical and engineering focused approach to automation.

Through advanced supply chain and planning we aim to have the lowest lead times for medical wires while also providing the best communication and updates about where a given project is in the process. We have taken great measures to improve the communication process in terms of fast quotes, proper specifications and quality checking.

If you have ideas about how to improve medical device supply chain, don’t hesitate to reach out. Click here for a medical wire equipment quote.

K-Wire (Kirschner Wire) vs. Steinmann Pin – Usage and Comparison

Many wire terms are used interchangeably, from mandrel to guide wire to k-wire to Steinmann Pin to Intramedullary pin to fixation pin. Most of the time, there are very subtle differences between the names, depending on design, diameter, threads, usage and the context of the speaker. We are here to dispel the myths and help you correctly name an orthopedic pin the next time you call us up.

Typical Steinmann Pin Attributes
Steinmann Pin Diameter: 1.6mm+
Steinmann Pin Material: Stainless Steel
Steinmann Pin Tip: Trocar Tip 15 Degrees
Steinmann Pin Usage: A stainless steel spike used for the internal fixation of fractures of long bones.
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Typical K-Wire Attributes
K-Wire Diameter: .9mm to 1.5mm
K-Wire Material: Stainless Steel or Nitinol
K-Wire Tip: Trocar Tip 15 Degrees
K-Wire Usage: K-wires are typically used for temporary fixation (basically as a guidewire) during some operations. After definitive fixation they are then removed. For instance, the k-wire is placed in the bone, a cannulated screw goes over the K-Wires, is screwed in, and the K-Wire is pulled out.
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puppy
Photo by – http://www.flickr.com/photos/23am/

In animal medicine, pins and wires are the most commonly used implants, due to cost and simplicity of surgical process when using them. The only downside is their limited usage when used alone and without additional equipment to treat fractures.(Whenever we talk about veterinary surgery we try to include a picture of a puppy to lighten the mood)

trocar2

 

The differentiation between a pin and a wire is typically the diameter. Smaller diameters are referred to as wires and larger diameters are referred to as pins. Although there is no standardized definition of diameter cut off, typically pins are between 1.5 mm (1/16 inch) and 6.5 mm (1/4 inch) in diameter. Kirschner wires (K-wires) are 0.9 to 1.5 mm (0.035, 0.045, 0.062 inches) in diameter. The most common tip for K-Wires and Steinmann Pins is a three-sided trocar tip being better suited to penetrating cortical bone and the later able to be braced against the endosteal surface of the bone’s cortex or applicable to lodging in cancellous bone. Our clients have the options of Trocar, Diamond (two-sided chisel), radius, or blunt tips.

Steinmann Pin and K-WiresBetween the two, the Steinmann Pin was introduced first as a way to stabilize fractures with a traction type device. The Steinmann Pin was driven through the skin and into the bone. It was used an anchor for the patient fracture. Steinmann Pins can also be called Intramedullary Pins or IM Pins.

Kirshner Wires came along after Steinmann Pins, when Martin Kirschner realized that the larger pins caused more bone damage as well as infection. He ended up creating his own device to insert chromed piano wire into willing patients. He also figured out a way to provide more tenstion which better aligns fracture fragments and provide tension to keep it in place.

For Additional Information, please consult – http://www.customkwiremanufacturer.com/history-of-steinmann-pins-and-kirschner-wires/