Superelastic medical instrument
Certain aspects relate to a superelastic medical instrument that of bending elastically through the tortuous pathways of an endoscope, returning to a straight shape upon deployment from the endoscope, and deploying straight along the axis of the end of the bronchoscope (within a tolerated margin) to distances of 2 cm or more.
1. A method of obtaining a tissue biopsy, the method comprising:
positioning a distal end of a working channel of an endoscope adjacent to a desired biopsy site;
advancing a tubular jacket through the working channel, the jacket including a biopsy needle assembly positioned within the jacket, the biopsy needle assembly comprising:
a needle formed from a superelastic alloy, the needle including:
a body portion extending from a distal end of the needle to a proximal end of the needle, and
an inner surface of the needle forming a lumen extending through at least a portion of the body portion to an opening in the distal end, wherein the lumen and the opening are configured to acquire a tissue biopsy; and
an elongate shaft attached to the proximal end of the needle at an overlap region;
positioning a distal end of the jacket within a predetermined distance from the biopsy site, the predetermined distance being less than a length of the needle extending distally beyond the overlap region;
actuating a first linear motion of a proximal end of the elongate shaft to drive extension of at least a portion of the needle out of the jacket into the biopsy site;
acquiring a tissue sample from the biopsy site through the opening of the needle; and
actuating a second linear motion of the proximal end of the elongate shaft to drive retraction of the needle out of the biopsy site.
2. The method of claim 1 , further comprising applying a pressure within the lumen to acquire the tissue biopsy.
3. The method of claim 1 , wherein the jacket has a handle coupled to a proximal end of the jacket configured to actuate the first and second linear motions of the proximal end of the elongate shaft along a longitudinal axis of the handle, the method further comprising actuating the handle to control the extension and the retraction of the needle.
4. The method of claim 3 , further comprising robotically controlling actuation of the handle.
5. The method of claim 1 , wherein:
the elongate shaft comprises a polymer tube secured at the overlap region at the proximal end of the needle, and
the actuation of the first linear motion comprises:
performing a first drive of the needle to extend the needle out of the jacket;
determining that the distal end of the needle is positioned out of the jacket; and
performing a second drive of the needle to extend the needle into the biopsy site.
6. The method of claim 5 , further comprising determining, after the first drive and before the second drive, that the overlap region is still positioned at least partly within the jacket.
7. The method of claim 5 , further comprising determining, after the first drive and before the second drive, that the overlap region is still positioned at least partly within the working channel of the endoscope.
8. The method of claim 5 , wherein performing the second drive comprises alternating extending the needle into the biopsy site and retracting the needle from the biopsy site a plurality of times.
9. The method of claim 1 , further comprising:
viewing the biopsy site using fluoroscopy; and
determining that the distal end of the needle is positioned at the biopsy site by viewing, via the fluoroscopy, a radiopaque material positioned around the needle near the distal end.
10. The method of claim 1 , wherein advancing the tubular jacket through the working channel comprises advancing the needle through a curved portion of the working channel, and wherein advancing the needle through the curved portion reversibly deforms the needle up to 10% from an original shape of the needle in which the body portion is straight.
11. The method of claim 10 , wherein reversibly deforming the needle comprises causing the superelastic alloy to transition from an austenite phase in which the needle is in the original shape to a martensite state.
12. The method of claim 11 , wherein driving extension of at least the portion of the needle out of the jacket into the biopsy site includes causing at least the portion of the needle to automatically transition back to the austenite phase and revert to the original shape.
13. A method of obtaining a tissue biopsy, the method comprising:
positioning a distal end of a working channel of an endoscope within a predetermined distance of a desired biopsy site;
advancing a biopsy needle formed from a superelastic alloy through the working channel, the biopsy needle comprising:
a body portion extending from a distal end of the needle to a proximal end of the biopsy needle, the proximal end of the needle attached to an elongate shaft at an overlap region, the predetermined distance being less than a length of the needle extending distally beyond the overlap region, and
an inner surface of the biopsy needle forming a lumen extending through at least a portion of the body portion to an opening in the distal end, wherein the lumen and the opening are configured to acquire a tissue biopsy;
driving extension of at least a portion of the biopsy needle into the biopsy site;
acquiring a tissue sample from the biopsy site through the opening of the biopsy needle; and
driving retraction of the biopsy needle out of the biopsy site.
14. The method of claim 13 , further comprising applying a pressure within the lumen to acquire the tissue biopsy.
15. The method of claim 13 , wherein the endoscope further comprises a tubular jacket including the biopsy needle, the advancing of the biopsy needle through the working channel involving advancing the tubular jacket through the working channel.
16. The method of claim 15 , wherein the jacket has a handle coupled to a proximal end of the jacket configured to actuate the driving extension and retraction of the biopsy needle via first and second linear motions of a proximal end of the elongate shaft along a longitudinal axis of the handle, the elongate shaft attached at the proximal end of the biopsy needle, the method further comprising actuating the handle to control the extension and the retraction of the biopsy needle.
17. The method of claim 16 , further comprising robotically controlling actuation of the handle.
18. The method of claim 16 , wherein the elongate shaft comprises a polymer tube secured at the overlap region, the method further comprising:
positioning a distal end of the jacket the predetermined distance from the tissue site; and
wherein actuating the first linear motion comprises:
performing a first drive of the needle to extend the needle out of the jacket;
determining that the distal end of the needle is positioned out of the jacket; and
performing a second drive of the needle to extend the needle into the biopsy site.
19. The method of claim 18 , further comprising determining, after the first drive and before the second drive, that the overlap region is still positioned at least partly within the jacket.
20. The method of claim 18 , further comprising determining, after the first drive and before the second drive, that the overlap region is still positioned at least partly within the working channel of the endoscope.