Audible frequency vibration of puncture-access medical devices

Ultrasonic vibration has been proven to help scalpels and puncture devices cut and cauterize, but creates a damaged tissue zone that may not be desirable. We have found that audible frequency vibration applied to a needle not only reduces puncture force more than ultrasonic vibration; it does not cause significant immediate tissue damage. Here we thus present a method for decreasing the force required to insert a puncture-access medical device and an analytical model for predicting performance of a hypodermic needle, which correlates well with tests and shows that needle insertion force is lowered not only by decreasing the outer diameter of the needle, but also by driving the device at its free state resonant (amplitude-maximizing) frequency. Finally, an in vivo histology study is conducted and suggests that audible frequency vibration results in the same degree of immediate local tissue damage as simple manually inserted needles, but that it causes significantly less immediate local tissue damage than ultrasonic vibration.