Medical tool for reduced penetration force with feedback means

Inventors

Frankhouser, Paul L. • Mulvihill, Maureen L. • Park, Brian M.

Assignees

Actuated Medical Inc

Abstract

A medical device for reducing the force necessary to penetrate living being tissue using a variety of reciprocating motion actuators, including piezoelectric, voice coil, solenoids, pneumatics or fluidics. The reciprocating actuator drives a penetrating member, such as a needle, through the tissue at a reduced force while the device detects the passage of the penetrating member through the tissue. Upon passage of the penetrating member through the tissue, electrical power to the reciprocating actuator is automatically terminated. One exemplary method for detecting this passage is via a fluid-containing syringe that is coupled to a channel within the penetrating member. Once the penetrating member tip has passed through the living tissue, the fluid within the syringe no longer experiences any pressure and a plunger within the syringe displaces indicating passage of the penetrating member tip. This motion can provide direct tactile feedback to an operator of the medical device or can automatically open a switch providing electrical power to the medical device. Alternatively, a pressure transducer can also monitor the pressure within the penetrating member channel and automatically activate the switch to cut off the electrical power.

Core Innovation

The invention relates to a method for reducing the force needed to penetrate living being tissue. The method applies biasing force to a biasing element and vibrates a penetrating member against the living being tissue using a reciprocating actuator that converts electrical energy to reciprocating motion.

Passage of the penetrating member through the living being tissue is detected by detecting a change in fluid pressure of the penetrating member. The change in fluid pressure is detected by detecting movement of the biasing element, where the biasing element dispenses fluid into the penetrating member and through the penetrating member and into the living being tissue.

The method automatically cuts off the electrical energy to the reciprocating actuator when the penetrating member has passed through the living being tissue. The disclosed implementations include loss-of-resistance style passage detection using a fluid-filled syringe coupled to a channel in the penetrating member with plunger movement, and pressure sensing via a pressure transducer monitoring pressure in the penetrating member channel.

The disclosed reciprocating actuator implementations include piezoelectric, Langevin actuator, Cymbal flextensional actuator, amplified piezoelectric actuator, voice coil, and solenoid, pneumatic, and fluidic variants. The description also addresses actuator geometry and configuration for mounting sensors or syringe and fluid components and describes electrical power cut-off logic based on detected pressure drop or movement associated with the biasing element.

Claims Coverage

Independent claim coverage is provided by one independent method claim. The claim includes multiple inventive features: biasing force with a biasing element, reciprocating vibration of a penetrating member driven by electrical energy, tissue passage detection via fluid-pressure change detected as biasing-element movement, and automatic cut-off of electrical energy when passage through tissue is detected.

Across the covered claims, the central inventive approach combines electrically driven reciprocating vibration of a penetrating member with passage detection based on a fluid-pressure change detected as movement of a fluid-dispensing biasing element, followed by automatically cutting off electrical power to the reciprocating actuator when passage through tissue is detected. Dependent refinements specify side-port fluid communication, syringe and plunger biasing-element configurations, actuator types such as piezoelectric and Langevin actuators, and vibration occurring during penetration.

Stated Advantages

Documented Applications