The increased miniaturization of medical devices such as surgical instruments and imaging tools continues to proliferate, paying off in many ways.

One of the integral items that have helped to facilitate the use of miniaturized medical devices has been the metal tube through which these devices pass, and that perform vital associated tasks such as aspiration, the cleanout of debris, and injection of fluids such as medications.

Composed of medical-grade metal in sizes commonly as thin as a pin, these tubes are used for a wide assortment of miniature medical procedures ranging from ultra-fine catheters to miniscule implants.

When designing and fabricating tubing for medical applications - especially the miniature ones - it is vital to be able to draw the necessary material to the needed diameter. Perhaps more important, the tube must have an even, smooth ID. Also, specialized shapes may be essential, requiring swaging, flaring or threading a portion of a tube, or making a one-piece component to avoid field failure.

For example, International Tube was involved in the development of a radioactive "seed" used in the localized treatment of tumors in prostate cancer cases. Known as brachytherapy, the treatment requires the manufacture of very small titanium tubes that are similar to a pinhead in size and shape.

Essentially, the fabrication of the seeds requires that a titanium tube that is about four pinheads thick be welded closed on one end. A radioactive isotope is placed into the enclosure, which is then closed at the open end. Depending on the treatment requirements, up to 100 tiny seeds are inserted into or near the prostate tumor. The radiation seeps through the metal, into the cancerous tissue next to the seeds.

Our firm provided the seed "hulls" for one of the first suppliers of radioactive seeds used for prostate cancer. He was involved with the design and assisted with multiple FDA trials and approvals, using multiple sizes of tubing until final design was accomplished. At that point, International Tube began fabricating 250,000 seed tubes at a time, which required the use of merely about 1,000 ft. of tight tolerance small diameter titanium tubing.

Another key need is for a smooth, clean ID with very low RMS (roughness) readings for many micro medical applications. We were called on to improve the safety in small-diameter tubes used for insertion of the fiber optic cameras used in microsurgery applications. Due to the delicate and pliable nature of fiber optics, the device manufacturer got reports that the fibers were occasionally getting snagged in the tubes. Worse yet, this snagging sometimes resulted in metal-to-metal contact, which produced distressing shocks to the surgical patients.

The problem was that the tube ID surface was not smooth enough for this virtually micro-level application. So our engineers analyzed the requirements and designed an ultra-smooth and ultra clean interior tube surface. The new tube design not only solved the snagging and shorting problems, but also saved the manufacturer almost 50 percent on expenditures for replacement fiber optics.

When the tube application is aspirating or clearing a surgical area, the performance is going to depend on the smooth operation of the tube. If the tube ID does not support the operation, it can collapse or congest, causing debris or tools or medication passing through it to deflect or get trapped.

We worked very closely with customer engineers to develop their Ultra Clean tube line to facilitate microsurgery applications that include the removal of debris during surgery. The smoothness ensures that tissue and tool debris created during procedures will no longer tend to collect in clean-out tubes, thereby reducing the need to clear or change tubes during operations.

Lance Heft is the CEO of International Tube, a specialty metal tubing and fabrication company supplying the medical, electronic and industrial markets with high quality products and personalized service in combination with cost-effective solutions.

For more information, contact International Tube 211 Commerce Ct Suite 105 Pottstown, Pa 19464; 800-517-5234. Visit the web site: www.internationaltube.com