Digital syringe with compensation control

• US 20100274180A1
• Filed: 04/24/2009
• Published: 10/28/2010
• Est. Priority Date: 04/24/2009
• Status: Active Grant

• Current Assignee: Kyphon SARL (Medtronic Plc)
• Original Assignee: Kyphon SARL (Medtronic Plc)
• Inventors: Leonard, Paul C., Donovan, Brian W., Arends, Thomas C., Leung, Andrea Y., Hubler, Robert B., Muller, Paul F., Barnes, Stephanie Ann, Eng, Lisanne, Thompson, David P., Schubert, Keith
• Granted Patent: US 8,002,748 B2
• Time in Patent Office: Days
• US Class Current: 604/65
• CPC Class Codes: A61B 17/8872 Instruments for putting said fixation devices against or away from the bone A61B17/7074, A61B17/808 take precedence
• CPC Class Codes: A61B 2017/0256 for the spine
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 5/1452 pressurised by means of pistons
• CPC Class Codes: A61M 5/16854 by monitoring line pressure
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate

Abstract

A syringe for performing a medical procedure includes a pressure sensor, a volume sensor, and a compensation circuit. The volume sensor measures a volume of a flowable material that is dispensed from the syringe, the pressure sensor measures a pressure being applied to the flowable material, and the compensation circuit calculates a delivered volume of the flowable material by accounting for system compliance (expansion) as the pressure is increased. By compensating for system compliance in this manner, a syringe can be used in high pressure procedures while still providing accurately controllable material delivery.

Claims

1. A syringe comprising:

a reservoir for holding a flowable material;

an actuator for dispensing the flowable material from the reservoir into a delivery path and to a delivery target;

a volume sensor to measure a first volume of flowable material dispensed from the reservoir;

a pressure sensor to measure a pressure applied to the flowable material; and

a compensation circuit to determine a second volume of flowable material delivered to the delivery target based on the first volume and the pressure.

2. The syringe of claim 1, further comprising a status indicator for indicating the second volume provided by the compensation circuit.

3. The syringe of claim 2, wherein the status indicator comprises a digital or analog display for providing a numeric indication of the second volume.

4. The syringe of claim 2, wherein the status indicator comprises a graphical representation of the second volume.

5. The syringe of claim 2, wherein the status indicator provides a warning when the pressure reaches a threshold pressure value or when the second volume reaches a threshold volume value.

6. The syringe of claim 5, wherein the warning comprises at least one of a visual-indicator, an aural indicator, or a tactile indicator.

7. The syringe of claim 1, wherein the compensation circuit comprises a user interface to allow input regarding at least one of the delivery path and the delivery target.

8. The syringe of claim 7, wherein the input interface comprises at least one of a button, a switch, a knob, a dial, and a keypad.

9. The syringe of claim 1, wherein the compensation circuit comprises a detection system for automatically identifying at least one component of the delivery path and delivery target.

10. The syringe of claim 9, wherein the detection system comprises a receiver for receiving identification information about the at least one of the delivery path and the delivery target over a wireless protocol.

11. The syringe of claim 1, further comprising an actuation controller for controlling the actuator in response to the second volume of flowable material determined by the compensation circuit.

12. The syringe of claim 11, wherein the actuation controller stops the actuator when the pressure reaches a threshold pressure value or when the second volume reaches a threshold volume value.

13. The syringe of claim 1, wherein the compensation circuit is adapted to determine the second volume of flowable material by determining an interior volume of the delivery path based on the pressure, and subtracting the interior volume of the delivery path from the first volume.

14. The syringe of claim 13, wherein the compensation circuit comprises a lookup table correlating a range of values for the pressure with a corresponding range of values for the interior volume of the delivery path.

15. The syringe of claim 13, wherein the compensation circuit comprises a mathematical model of an internal volume of the deliver path as a function of the pressure.

16. The syringe of claim 1, wherein the volume sensor comprises a flow meter.

17. The syringe of claim 1, wherein the syringe further comprises a plunger slidably positioned within the reservoir,

wherein the volume sensor comprises a linear potentiometer having a slider, and

wherein the slider is coupled to the plunger by a cable.

18. A method for delivering a flowable material from a reservoir through a delivery path to a surgical delivery target, the method comprising:

measuring a first volume of the flowable material dispensed from the reservoir;

measuring a pressure applied to the flowable material;

determining an actual volume of the flowable material delivered to the surgical delivery target based on the pressure and the first volume of flowable material.

19. The method of claim 18, wherein determining the actual volume comprises:

determining an interior volume of the delivery path at the pressure; and

subtracting the interior volume from the first volume.

20. The method of claim 18, further comprising providing at least one of a visual, aural, or tactile indication when the second volume reaches a threshold volume or when the pressure reaches a threshold pressure.