Steerable needle

• US 20040133168A1
• Filed: 12/18/2003
• Published: 07/08/2004
• Est. Priority Date: 12/23/2002
• Status: Active Grant

• Current Assignee: Afrooz R. Ebrahimi, Robert N. Rohling, Septimiu E. Salcudean, Stephen H. Okazawa
• Original Assignee: Afrooz R. Ebrahimi, Robert N. Rohling, Septimiu E. Salcudean, Stephen H. Okazawa
• Inventors: Okazawa, Stephen H., Ebrahimi, Afrooz R., Salcudean, Septimiu E., Rohling, Robert N.
• Granted Patent: US 7,662,128 B2
• Time in Patent Office: Days
• US Class Current: 604/164.13
• CPC Class Codes: A61B 10/04 Endoscopic instruments
• CPC Class Codes: A61B 17/3478 Endoscopic needles, e.g. for infusion biopsy needles A61B10/0233; catheters with injection needles A61M25/0067
• CPC Class Codes: A61B 2010/045 Needles pointed biopsy devices with vacuum aspiration A61B10/0283
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/00331 with preformed bends
• CPC Class Codes: A61B 2017/00398 using powered actuators, e.g. stepper motors, solenoids
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2017/3413 guided by ultrasound

Abstract

The invention relates to a needle guidance system provided by a needle with a steerable tip. The needle has a cannula and a stylet. The stylet adjacent to its tip has a naturally curved portion The stylet is movable in two degrees of freedom with respect to the cannula—axial translation and axial rotation with respect to the cannula axis. When extended, the stylet curves off-axis and provides cannula tip steering. Driving and/or steering systems may be provided to the orientation and relatively move the stylet.

Claims

1. A needle structure comprising a hollow, outer cannula having a main longitudinal axis and an open end, and a longer stylet having a leading end adjacent to said open end and having a curved portion with a pre-defined curvature adjacent to said leading end, mounting means mounting said stylet coaxially within said outer cannula so that said stylet and cannula may be relatively translated along said main axis from a sheathed position wherein substantially all of said curved portion of said stylet is within said cannula to an extended position wherein a selected extended part of said curved portion of said stylet projects beyond said open end, said cannula being stiffer than said stylet, so that when said stylet is in its said sheathed position it assumes a shape primarily defined by said cannula, and when said stylet is in its said extended position, said extended part of said stylet assumes a curved shape primarily determined by said pre-defined curvature, and said leading end extends from said cannula in a direction determined by the rotation of said stylet about said main axis

2. A needle structure as defined in claim 1 wherein said mounting means mounts said stylet to also permit relative rotational movement of said stylet and said cannula.

3. A needle structure as defined in claim 2 further comprising means for indicating said direction of said leading end.

4. A needle structure as defined in claim 3 wherein said means for indicating comprises marking on said stylet.

5. A needle structure as defined in claim 2 further comprising a casing, drive means, said drive means including means to rotate said stylet about said main axis and means to relatively translate said stylet and said cannula along said main axis from said sheathed position to said extended position, said means to rotate and said means to translate being mounted within said casing.

6. A needle structure as defined in claim 5 wherein said means to rotate and said means to relatively translate are connected to said stylet and said cannula is fixed to said casing

7. A needle structure as defined in claim 5 further comprising sensing means for sensing the rotation of said stylet relative to said casing and further means for sensing said extended position of said stylet, operator input means for specifying a desired said direction and a desired said extended position, and computer means for controlling said means for actuating said means to rotate and said means to relatively move to achieve said desired direction and desired extended position.

8. A needle structure as defined in claim 7 wherein said operator input means is mounted on said casing.

9. A needle structure as defined in claim 7 wherein said operator input means includes a stylet rotation control and a translation control means for controlling said means to rotate and said means to relatively translate respectively, said rotation control means determining said direction relative to said casing, and said translation control means determining said extended part.

10. A needle structure as defined in claim 7 further comprising a medical imaging system to sense the position of a target to which said needle structure is directed, computer means to provide a detected position of said cannula within the images provided by said medical imaging system, and display means for displaying said target and said detected position of said cannula to an operator.

11. A needle structure as defined in claim 10 further comprising sensing means for sensing the position of said needle structure, computer means for expressing said sensed position of said needle structure in the coordinates of said medical imaging system, and means for superimposing said sensed position of said needle structure in said coordinates of said medical imaging system onto said display means to display said sensed position of said needle structure with said target and said detected position of said cannula in a manner to assist an operator in steering said needle structure.

12. A needle structure as defined in claim 1 further comprising a medical imaging system to sense the position of a target to which said needle structure is directed, computer means to provide a detected position of said cannula within the images provided by said medical imaging system, and display means for displaying said target and said detected position of said cannula to an operator.

13. A needle structure as defined in claim 10 further comprising a mechanical guide, said mechanical guide facilitating alignment of said cannula to the said display means.

14. A needle structure as defined in claim 12 further comprising a mechanical guide, said mechanical guide facilitating alignment of said cannula to the said display means.

15. A needle structure as in claim 10 wherein said computer means generates a path to said target and displays it on said display means.

16. A needle structure as in claim 12 wherein said computer means generates a path to said target and displays it on said display means.

17. A needle structure as defined in claim 7 further comprising means for applying a small motion pattern to said stylet, said small motion pattern being detectable by medical imaging techniques.

18. A needle structure as defined in claim 10 wherein said computer generates a sequence of said desired directions and said desired extended positions of said stylet relative to said cannula to effect a cannula path to said target as the operator moves said needle structure.

19. A needle structure as defined in claim 15 further comprising a robot and wherein said computer includes means for controlling said robot to insert said needle structure on said path.

20. A needle structure as in claim 1 wherein said cannula has a reinforced segment of higher stiffness adjacent to said open end.

21. A method of controlling the path of movement of a needle structure toward a target wherein said needle structure comprises a hollow outer cannula having a main longitudinal axis and an open end, a stylet having a curved portion having a pre-defined curvature adjacent to its leading end, said stylet being mounted coaxially within said outer cannula with said leading end adjacent to said open end, so that said stylet may be rotated about said main axis and said stylet and cannula relatively moved axially relative to said main axis between a sheathed position wherein said curved portion of said stylet is within said cannula to an extended position wherein said stylet projects a selected distance beyond said free end to provide a curved extended part of said stylet having a curvature approaching said pre-defined curvature with said leading end extending from said cannula in a controlled direction determined by rotation of said stylet about said main axis, said method comprising, moving said stylet and said cannula on said path in a selected direction toward said target and adjusting said selected direction by rotating said stylet within said cannula to a selected orientation and then relatively moving said stylet and said cannula to position said stylet in said extended position, and to provide said curved extended part with said leading end pointing in said controlled direction determined by said selected rotation, then advancing the needle along said path in an adjusted direction.

22. A method as defined in claim 21 where said relatively moving comprises moving said stylet relative to said cannula.

23. A method of detecting a needle in an ultrasound image comprising median filtering to remove speckle noise, detecting needle point candidates at the peaks in the derivative function along several directions perpendicular to an approximate direction of the needle, fitting such point candidates to a line, using a Hough transform improve on the resulting line, and finding a polynomial fit to those needle point candidates that are close to the line determined by the Hough transform.

24. A method of guiding a steerable needle to a target, sensing by medical imaging to provide an image of said target and said needle, display said image to an operator, and providing a control signal via a computer to control the needle direction.