Fluid Percussion System And Method For Modeling Penetrating Brain Injury

Abstract

A fluid percussion system for modeling penetrating brain injury includes a fluid percussion device that takes inputs in the form of pressurized gas and electrical signals from a computer and outputs a single hydraulic pulse, or multiple hydraulic pulses in quick succession. The fluid percussion device may include a pneumatic cylinder assembly and a hydraulic cylinder assembly that is actuated by the pneumatic cylinder assembly to produce the hydraulic pulse(s) of pressurized fluid. Each pulse may be used to rapidly inflate and deflate an attached balloon (representing a brain penetrating device). The balloon may be inserted in a test specimen, and the rapid inflation and deflation of the balloon creates a lesion that simulates a penetrating brain injury. A calibration system that employs an optical sensor may be used to determine maximum balloon diameter achieved during rapid inflation.

1 . A balloon calibration system for determining a diameter of a hydraulically inflated balloon, comprising:
 a needle;   a balloon made of an uniform expandable elastic material, configured to be spherical in shape when inflated;   a base that holds the needle having the balloon attached thereto that is inflated by hydraulic fluid exiting the needle;   an optical sensor having an optical laser that extends transverse to a longitudinal axis of the needle; and   a measurement device for measuring a distance between the optical laser and the needle.   
     
     
         2 . The system of  claim 1 , wherein the optical sensor includes two arms vertically extending from an optical sensor support, wherein the optical laser extends horizontally between the two vertical arms, wherein the vertical arms are separated by a horizontal distance that receives the needle with the balloon therebetween so that the balloon when inflated may break the optical laser, wherein the optical sensor support is linearly moveable along a vertical rail disposed on the base so as to position the optical laser a given distance from the needle. 
     
     
         3 . The system of  claim 2 , wherein the optical sensor support is selectively positioned on the rail between at least a first vertical position in which the balloon when inflated breaks the optical laser and at least a second vertical position in which the balloon when inflated does not break the optical laser. 
     
     
         4 . The system of  claim 3 , wherein the first position and the second position of the optical sensor support are based on a radius of the balloon when dynamically inflated by a pulse of the hydraulic fluid being delivered to the needle. 
     
     
         5 . The system of  claim 4 , further comprising an indicator mechanism that alerts a user when the optical laser has been broken by the inflated balloon. 
     
     
         6 . The system of  claim 1 , farther comprising a potentiometer and an optical switch control circuit mounted on the base, that operates of the optical sensor. 
     
     
         7 . The system of  claim 2 , wherein the measurement device includes a ruler fixedly disposed on the base, the ruler being vertically disposed on a linear rail holder adjacent the rail. 
     
     
         8 . The system of  claim 7 , wherein the measurement device further includes a gage provided on the moveable optical sensor support, the gage having an end that points to the ruler for designating a measurement on the ruler which provides the distance between the optical laser and the needle and correlates to the diameter of the hydraulically inflated balloon. 
     
     
         9 . The system of  claim 1 , wherein the base includes a manipulator arm removeably secured to a calibration unit base, wherein the manipulator arm includes a needle holder that removeably secures the needle to the manipulator arm. 
     
     
         10 . The system of  claim 1 , wherein the optical sensor includes two arms vertically extending from an optical sensor support, wherein the optical laser extends horizontally between the two vertical arms, wherein the base includes a manipulator arm fixed permanently to a calibration unit base, the manipulator arm being that holds the needle so that a distal end portion of the needle having the balloon extends between the arms of the optical sensor. 
     
     
         11 . The system of  claim 10 , wherein the optical sensor support is linearly moveable with a rail along a guide block disposed on the base, the optical sensor support and rail being moveable so as to selectively position the optical laser a given vertical distance from the needle. 
     
     
         12 . The system of  claim 11 , wherein one or more screws are provided on the rail, wherein the optical laser is fixed at the given vertical distance from the needle by tightening of the screws. 
     
     
         13 . The system of  claim 11 , wherein the measurement device includes a micrometer head with a measurement display for displaying a measurement which provides the distance between the optical laser and the needle and correlates to the diameter of the hydraulically inflated balloon, wherein the micrometer head is secured to a sensor measurement and support structure fixedly disposed on the base. 
     
     
         14 . The system of  claim 13 , further comprising a spring vertically extending between a first end and a second end, the first end being disposed on the support structure and the second end being disposed on the rail, wherein the spring is extended or compressed based on the movement of the rail along the guide block. 
     
     
         15 . A balloon calibration system for determining a diameter of a hydraulically inflated balloon, comprising:
 a hollow needle having a distal end portion;   a balloon made of an uniform expandable elastic material, and spherical when inflated, attached to the distal end portion of the needle;   a base holds the needle;   an optical sensor having an optical laser, wherein the optical sensor includes two arms extending from an optical sensor support, wherein the optical laser extends horizontally between the two arms, wherein the base holds the needle so that the distal end portion of the needle extends between the arms of the optical sensor; and   a measurement device for measuring a distance between the optical laser and the needle.   
     
     
         16 . The system of  claim 15 , wherein the measurement device includes a ruler and a gage, and wherein the gage has an end that points to the ruler for designating a measurement on the ruler which provides the distance between the optical laser and the needle and correlates to the diameter of the balloon when inflated. 
     
     
         17 . The system of  claim 15 , wherein the measurement device includes a micrometer head with a measurement display for displaying a measurement which provides the distance between the optical laser and the needle and correlates to the diameter of the balloon when inflated. 
     
     
         18 . The system of  claim 15 , wherein the optical sensor support is moveable along a rail disposed on the base so as to selectively position the optical laser a given distance from the needle. 
     
     
         19 . The system of  claim 18 , wherein the optical sensor support is selectively positioned on the rail between at least a first position and a second position,
 wherein, in the first position, the optical laser is broken by the balloon when dynamically inflated by a pulse of hydraulic fluid, and   wherein, in the second position, the balloon when dynamically inflated fails to break the optical laser.   
     
     
         20 . The system of  claim 19 , further comprising an indicator mechanism that alerts a user when the optical laser has been broken by the inflated balloon.