Putnam Plastics Offers New Catheter Marker Bands

Dayville, Conn.-based Putnam Plastics Corp., a provider of extrusion capabilities for minimally invasive medical devices, has developed a line of polymer marker bands for fluoroscopic illumination of catheter tips used in minimally invasive medical procedures.

Traditionally, marker bands are short, thin-walled tubes made from gold or platinum placed on the tip of the catheter shaft, providing high levels of visibility under fluoroscopy (radiopacity). Radiopacity allows surgeons to locate the catheter deep inside the body with precision, enabling the deployment of balloons, stents, and other devices into blood vessels.

These traditional marker bands require a multi-step forming process to create seamless small diameter tubes. Special manufacturing equipment is used to crimp or swage metal bands to the polymer shaft tip so they do not fall off during the medical procedure. This process is costly and time consuming, and quality controls to ensure sufficient mechanical bonding between these dissimilar materials can be significant, according to the company.

These new marker bands, Putnam executives claim, will save costs because they are made from tungsten-filled polymers such as nylon, urethane and thermoplastic elastomers. Tungsten is a rare metal with a similar density to gold. The polymer used would be the same polymer the catheter shaft is made of, which would facilitate bonding for a more secure assembly. The markers are thermally bonded to the catheter shafts, and the polymeric covering on the tungsten protects blood vessels from trauma. Tungsten loadings range from 65 percent to 80 percent by weight to meet radiopacity requirements.

“Our thermoplastic composite bands are cut from tubes extruded in a single process, which can provide cost savings and shorten lead times,” said Ray Rilling, general manager at Putnam.

Putnam Plastics offers polymer marker bands with inside diameters ranging from 0.014 inches (0.356 mm) to 0.200 inches (5.080 mm) and wall thicknesses ranging from 0.002 inches (0.051 mm) to 0.030 inches (0.762 mm).