Medical Tool With Electromechanical Control and Feedback

Abstract

A medical device for reducing the force necessary to penetrate living being tissue using a variety of reciprocating motion actuators. 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, a feedback system monitors electromechanical properties of a control signal of the device and automatically modifies control based thereon, e.g., electrical power to the reciprocating actuator is automatically terminated.

1 - 37 . (canceled) 
     
     
         38 . A device, comprising:
 a driving actuator having a displaceable member formed of a first portion detachably connected to a second portion, a rear mass, and a piezoelectric stack formed between the displaceable member and rear mass;   a penetrating member coupled to a distal end of said second portion of said driving actuator; and   an electrical power feedback subsystem for regulating the operation of said driving actuator based on a sensed condition,   wherein said second portion further comprises a channel extending entirely therethrough.   
     
     
         39 . The device of  claim 38  further comprising a force sensor disposed at a proximal end of said driving actuator. 
     
     
         40 . The device of  claim 39  wherein said force sensor further comprises a piezoelectric ring. 
     
     
         41 . The device of  claim 38  further comprising a phase angle detector for detecting passage of said distal end of said penetrating member through a preselected space within living tissue based on a phase angle of a control signal of said driving actuator. 
     
     
         42 . The medical device of  claim 38  further comprising a voltage detector for detecting passage of said distal end of said penetrating member into a preselected space within living tissue based on a voltage of a control signal of said driving actuator. 
     
     
         43 . The device of  claim 38 , further comprising a phase angle detector for detecting changes in device operation conditions as the device is exposed to various media. 
     
     
         44 . The device of  claim 38  wherein said second portion further comprises a channel extending entirely therethrough. 
     
     
         45 . The device of  claim 44 , wherein said second portion further comprises an opening that is not in communication with said channel. 
     
     
         46 . The device of  claim 44  wherein said channel comprises a first section that accepts a proximal end of said penetrating member. 
     
     
         47 . The device of  claim 44  wherein said channel comprises a second section that accepts material capable of being introduced to an inner volume of the penetrating member. 
     
     
         48 . The device of  claim 44 , wherein said channel accepts the insertion of one of a syringe and a catheter. 
     
     
         49 . A method, comprising:
 providing power from a power source to an actuator of a medical device, the actuator configured to convert the provided power into reciprocating motion at a first frequency that is transferred to a sharps member coupled to the actuator;   detecting a reference resonance frequency of the medical device; and   automatically adjusting the power provided to the actuator to cause the actuator to vibrate at the reference resonance frequency.   
     
     
         50 . The method of  claim 49 , wherein said step of detecting a reference resonance frequency comprises:
 adjusting the power provided by the power source to cause the actuator to reciprocate at a plurality of frequencies within a range of frequencies,   using an impedance analyzer in communication with the actuator to measure an impedance response signal of the actuator respective to each of the plurality of frequencies,   storing a first value representative of each of the impedance response signals and a second value of each of the corresponding plurality of frequencies in a machine readable medium,   comparing each of the stored first values of each of the impedance response signals,   selecting a minimum first value relative to the other stored first values;   determining the frequency corresponding to the minimum first value and   storing the minimum first value to be the reference resonance frequency.   
     
     
         51 . The method of  claim 50 , wherein said range of frequencies comprises frequencies in the range of 19.5 kHz to 21.5 kHz. 
     
     
         52 . The method of  claim 50 , wherein said range of frequencies comprises frequencies in the range of 21 kHz to 24 kHz. 
     
     
         53 . The method of  claim 52 , further comprising:
 detecting a change in resonance frequency of the medical device relative to a threshold resonance frequency change;   determining an updated resonance frequency of the medical device; and   automatically adjusting the power provided to the actuator to cause the actuator to reciprocate at the updated resonance frequency.   
     
     
         54 . The method of  claim 53 , wherein the step of detecting a change in resonance frequency of the medical device relative to a threshold resonance frequency change, comprises:
 adjusting the power provided by the power source to cause the actuator to reciprocate at a plurality of frequencies within a range of frequencies,   using an impedance analyzer in communication with the actuator to measure an impedance response signal of the actuator corresponding to each of the plurality of frequencies,   storing a first value representative of each of the impedance response signals and a second value of each of the corresponding plurality of frequencies in a machine readable medium,   comparing each of the stored first values of each of the impedance response signals,   selecting a minimum first value relative to the other stored first values,   determining the frequency corresponding to the minimum first value; and   determining a difference between the frequency corresponding to the minimum first value relative to the reference resonance frequency and comparing that difference to the threshold resonance frequency change, and   determining the updated resonance frequency by selecting the minimum first value and storing said minimum first value as an updated resonance frequency.   
     
     
         55 . The method of  claim 52 , further comprising:
 detecting a change in a detected phase angle relative to a threshold phase angle;   automatically adjusting the power provided by the power source to cause the actuator to reciprocate by a predetermined frequency change relative to the reference resonance frequency.   
     
     
         56 . The method of  claim 55 , wherein the step of detecting a change in a detected phase angle relative to a threshold phase angle difference, comprises:
 detecting, at a first time, a phase angle of the device operating at the reference resonance frequency at a first time,   detecting, at a second time, a phase angle of the device operating at the reference resonance frequency, and   
       comparing a difference between the phase angle of the first time and the phase angle of the second time to a predetermined threshold phase angle difference.