[The Huber needle as a special cannula for the puncture of implanted ports and pumps--a mistake in multiple variations].

Huber-point needles, which are thought to be noncoring, are usually recommended for puncture of implanted drug-delivery devices, such as ports and pumps. Nevertheless, we found occlusion by silicone chips deriving from the silicone inlet septum to be a major technical complication. Electron microscopic investigations demonstrated substantial loss of material from the port membrane after repeated puncture with this type of needle. During an in vitro test, multiple puncture with Huber-type cannulas led to a pressure-dependent leakage of a port after only 150 to 750 insertions of a needle. In addition, the forces necessary for puncture or for withdrawal of the needle were increased with Huber-point needles, possibly due to a coring effect. Another disadvantage of the available port needles is the formation of a hook at the tip, which may lead to additional lesion of the port or pump membrane. In our opinion, resterilization of Huber needles, recommended by the manufactures, is not advisable, because it is well known that safe sterilization of small lumina, e.g., the lumen of the needle, is impossible.