US20020022800A1 - Surgical needle with hand-actuable lock mechanism - Google Patents

Abstract

A surgical needle assembly including a hollow needle body, a push rod slidingly fit within the hollow needle body, and a hand-actuable lock mounted on the needle body. The lock selectively limits movement of the push rod relative to the needle body in response to a squeezing or releasing of the lock.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application is a continuation of U.S. patent application Ser. No. 09/313,881, filed on May 18, 1999 and entitled SURGICAL NEEDLE WITH HAND-ACTUABLE LOCK MECHANISM.[0001]
BACKGROUND OF THE INVENTION
• This invention relates generally to surgical tools and, more specifically, to a surgical needle with a hand-actuable lock mechanism for holding one part of the needle approximately fixed relative to another part. One embodiment of the needle includes a hollow needle through which a push rod slides, and the lock is used to hold the push rod fixed relative to the hollow needle. Such hollow needle/push rod assemblies often are used when depositing, sampling or removing material within living tissue.[0002]
• The lock mechanism of the present invention may be mounted on various types of needles, push rods, catheters, stents, trocars, cannulas, wires and stylets. The detailed description of the invention, below, is based on an embodiment that may be used in prostate brachytherapy, in which radioactive seeds are implanted in a human prostate while the needle and seeds are monitored by ultrasound sensors and imaging devices. U.S. Pat. Nos. 4,461,280, 4,700,692 and 4,815,449, the disclosures of which are incorporated herein by reference, disclose background information about the deposition of radioactive seeds within human tissue.[0003]
• The lock mechanism may be used with other known surgical tools, such as trocar and cannula assemblies, in which an inner member such as a rod or inner hollow needle slidingly fits within and extends through an outer hollow needle to block or interact with an open end of the outer needle. For example, fluid and tissue samples may be taken from a specific part of the body by penetrating the desired part of the body with the end of a needle, and then removing a rod from within the needle to open a hollow cavity in the needle and admit fluid or tissue. A syringe or other injection device may also or alternatively be attached to the needle if fluids or solids are to be injected. Examples of such tools are found in U.S. Pat. Nos. 5,207,647, 5,242,427, 5,290,304, 5,368,046, and 5,556,411, the disclosures of which are incorporated herein by reference.[0004]
SUMMARY OF THE INVENTION
• The lock of the present invention will be described with reference to a surgical needle that includes a hollow, sharp, pointed needle that extends from a grip, mounted on the needle. A push rod extends through the hollow needle to push material through the needle, and the lock is operatively connected to both the needle and rod to lock the rod relative to the needle. The lock is formed as part of the grip, and is shaped so that a surgeon may hold and direct the point of the needle, and lock and unlock the lock to selectively limit movement of the push rod relative to the needle.[0005]
• This embodiment of the needle may be loaded with material such as radioactive seeds to be deposited within living tissue. When so loaded, the needle assembly is in a loaded position. The material contained within the needle assembly may be extruded by moving either the push rod or the hollow needle relative to the other. When the push rod is inserted fully into the hollow needle, the needle assembly is in an empty position.[0006]
• The needle and push rod may be used collectively to deposit material in living tissue, preferably by inserting the needle loaded with material into the tissue. The push rod then is held in a fixed position relative to the tissue and the needle is slid back over the push rod, forcing material out of the needle as the needle is withdrawn from the tissue. By carefully controlling the relative motion of the push rod to the needle, material may be distributed through the tissue as desired, typically along a line traced by the point of the needle as it is withdrawn from the tissue.[0007]
• The lock mechanism preferably may be controlled by squeezing and releasing the grip. For example, the lock mechanism may be unlocked when the grip is squeezed, and locked when the grip is not squeezed. This has been found to be particularly useful for surgical procedures, because the surgeon will need to have a hand on the device to control its relative motion anyway, and the squeezing of the lock does not limit the surgeon's ability to maneuver the needle.[0008]
• When the lock of the assembly is unlocked, the needle preferably slides freely relative to the push rod. In one embodiment of the invention, the lock mechanism is formed by fingers that extend toward the push rod from outwardly biased arms of the grip. Holes are formed within the fingers, oversized relative to the push rod so that it may slide freely through the holes when the arms are squeezed.[0009]
• The advantages of the present invention and its various embodiments will be understood more readily after a consideration of the drawings and the Detailed Description of the Preferred Embodiment.[0010]
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a view showing a needle assembly according to the present invention being inserted into living tissue, with the needle assembly in its loaded position.[0011]
• FIG. 2 is an enlarged isometric view of the needle assembly of FIG. 1, shown in its empty position.[0012]
• FIG. 3 is a greatly enlarged cross-sectional view of the end portion of the assembly shown in FIGS. 1 and 2, shown in a loaded position, with the push rod and radioactive seeds contained within the needle not cross-sectioned.[0013]
• FIG. 4 is a view showing an alternative embodiment of the needle assembly of FIG. 1 after it has been inserted into living tissue as far as desired, with the lock of the assembly squeezed so that the needle slides freely relative to the push rod.[0014]
• FIG. 5 is a view showing the needle assembly of FIG. 4 after the needle has been withdrawn from the living tissue as far as desired while holding the push rod stationary relative to the living tissue, leaving a trail of seeds within the tissue, with the lock of the assembly squeezed so that the needle slides freely relative to the push rod.[0015]
• FIG. 6 is a view showing the needle assembly of FIG. 5 being removed from the living tissue, with the needle locked relative to the push rod so that no additional seeds are deposited into the tissue as the assembly is removed.[0016]
• FIG. 7 is a greatly enlarged plan view of the grip portion of the assembly shown in FIGS.[0017]4-6, without a push rod inserted into the grip and needle portions, and with a locked position of the arms of the grip shown in dashed lines and a protective sheath shown in cross section.
• FIG. 8 is a cross-sectional view of the grip shown in FIG. 8, taken along line[0018]8-8 in FIG. 7, shown on approximately the same scale as in FIG. 7.
• FIG. 9 is a cross-sectional view of the grip portion of the assembly shown in FIGS.[0019]4-6, taken from a point of view similar to that in FIG. 7, with a push rod inserted into the grip and needle portions, and with the lock of the assembly squeezed so that the push rod slides freely relative to the needle, shown on approximately the same scale as in FIG. 7.
• FIG. 10 is a cross-sectional view of the grip shown in FIG. 9, taken along line[0020]10-10 in FIG. 9, shown on approximately the same scale as in FIG. 7.
• FIG. 11 is a cross-sectional view of the grip portion of the assembly shown in FIGS.[0021]4-6, taken from a point of view similar to that in FIG. 7, with a push rod inserted into the grip and needle portions, and with the needle locked relative to the push rod so that the needle does not slide freely relative to the push rod, shown on approximately the same scale as in FIG. 7.
• FIG. 12 is a cross-sectional view of the grip shown in FIG. 11, taken along line[0022]12-12 in FIG. 11, shown on approximately the same scale as in FIG. 7.
• FIG. 13 is a cross-sectional view of the grip shown in FIG. 1, taken along line[0023]13-13 in FIG. 1, shown on approximately the same scale as in FIG. 7.
• FIG. 14 is a cross-sectional view of the grip shown in FIG. 13, rotated about the long axis of the needle.[0024]
• FIG. 15 is an isometric view of the alternative embodiment of the needle assembly of FIGS.[0025]4-12.
• FIG. 16 is a view of the needle assembly embodiment of FIG. 16, viewed similarly to FIG. 1, with the needle in its loaded position, inserted into living tissue.[0026]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• Referring to FIG. 1, a[0027]surgical needle assembly10 according to the present invention is shown inserted into a portion of ahuman body100.Assembly10 includes an open-ended,hollow needle12, also referred to as a slender outer tube or delivery tube. Agrip14 is mounted on or attached to one end ofneedle12 so thatneedle12 may be manipulated easily by a human hand. Apush rod16 extends throughneedle12 to form a type of plunger or piston, as described in more detail below. Ahandle18 is formed on the end ofrod16, so thatrod16 may be manipulated by a human hand, separately or in conjunction with the manipulation ofneedle12. Preferably,needle12 andpush rod16 are made of surgical grade stainless steel, andgrip14 andhandle18 are made of medical grade polycarbonate, but other metals, plastics and composites may be used.
• Referring to FIG. 2,[0028]assembly10 is shown in isometric view, with portions ofneedle12 androd16 removed to fit the image of the assembly within the drawing page.Grip14 includes alock20 to holdrod16 relative toneedle12 by frictional forces betweenlock20 androd16, when the moving elements oflock20 are allowed to move outwardly to an unsqueezed position.Rod16 is therefore locked so that it does not slip into or out ofneedle12. Whenlock20 is squeezed, as shown in dashed lines in FIG. 2, the frictional forces are removed, so thatrod16 slips freely relative toneedle12. This allowsrod16 to be used as a push rod to push out any material stored inhollow needle12.
• Still referring to FIG. 2, a[0029]sharp point22 is formed at the end ofneedle12 to pierce and penetrate the flesh and tissue of a human body, so thatneedle12 may be used as a delivery tube to deliver material to within the flesh or tissue of a human body. For example, in FIG. 3 details of such material loaded inneedle12 are shown in a greatly enlarged cross-sectional view.Radioactive seeds24aandspacers24b, referred to collectively asseeds24, are held withinhollow needle12, ready for delivery to a diseased prostrate.Rod16 includes ablunt end26 that may be used to pushseeds24 relative toneedle12, and thereby forceseeds24 out ofneedle12 as desired.
• An alternative embodiment of the surgical needle assembly of the present invention is shown in FIGS. 4 through 12,[0030]15 and16.Assembly10 includes aneedle12 and pushrod16 as in the embodiment of FIGS. 1 through 3,13 and14, but is formed with agrip114 that is shorter thangrip14 of FIGS.1-3. However, care must be exercised when using the embodiment of FIGS. 4 through 12 not to inadvertently squeezelock20, thereby unlockingrod16 relative toneedle12. For example, it has been found best to holdassembly10 as shown in FIG. 16 to avoid unlockingrod16.
• In FIGS. 1, 4,[0031]5, and6,assembly10 is shown in use to deliverseeds24, just discussed. Beginning with FIG. 1,needle12 is inserted into the flesh and tissue of ahuman body100 to a desired point, whilelock20 is in its biased, locked position to holdrod16. This prevents undesired movement ofrod16 relative toneedle12.
• After insertion to the desired point, for example within a[0032]prostate102, as shown in FIG. 4, the operator's hands may be readjusted to a position suitable for depositing seeds withinprostate102.Lock20 may be held in an unlocked position by one hand (left hand shown), while handle18 ofrod16 is held by the other hand (right hand shown). While squeezinglock20 to unlock the locking mechanism, as shown in FIG. 5, and while holdinghandle18 ofrod16 steady relative totissues100,needle12 is withdrawn fromtissues100. Alternatively, two surgeons may perform the procedure as a team, with onesurgeon holding handle18, while the other surgeon withdrawsneedle12.
• As[0033]needle12 is withdrawn,radioactive seeds24 are forced out ofneedle12 byblunt end26 ofrod16. Becauseneedle12 moves androd16 andseeds24 remain essentially stationary relative tobody100 during this step of the procedure,seeds24 are deposited in a line corresponding to the prior location ofneedle12. As used herein, “line” may be more or less precise, depending on the type of material deposited inbody100, the properties of the tissue in which the line is deposited, the skill of thesurgeon operating assembly10, and other factors. A deposited line may also be straight or curved, regular or irregular, based on similar factors and based on the flexibility ofneedle12 androd16.
• Once a desired amount of[0034]seeds24 have been deposited inbody100, or once needle12 has been withdrawn a desired amount frombody100, the squeezing pressure onlock20 is removed. This locksrod16 relative toneedle12, so thatneedle12 androd16 may be removed without pushing additionalradioactive seeds24 out ofneedle12, as shown in FIG. 6. If desired, the hand position onassembly10 may be changed for this final removal step, as shown in FIG. 6.
• Referring now to FIGS. 7 through 12,[0035]lock20 and other features ofdevice10 will be described in detail. In FIG. 7, lock20 is shown prior to the insertion ofrod16 intoneedle12.Lock20 includes a spring in the form of a pair of outwardly extending, resiliently biasedarms28, molded from a resilient material such as the polycarbonate preferred forgrips14 or114, so that the natural, unsprung position of the arms is splayed outwardly, as shown in FIG. 7. Whenarms28 are squeezed together to allowrod16 to be inserted,arms28 are springs that press outwardly relative torod16, toward the arms' natural unsprung position.
• Polycarbonate is preferred because it tends to retain its shape memory over time, even if[0036]arms28 are left in an inward position such as that shown in FIG. 9. Other materials, such as nylon or polypropylene, tend to assume the inward position, so that the effectiveness oflock20 is lost over time. Regardless of the material used, it is best to leavearms28 in an extended, outward position as shown in FIG. 7, until the time of use ofassembly10.
• Each[0037]arm28 includes at least one inwardly extendingfinger30, and eachfinger30 includes a hole orpassageway32, preferably a tapered hole that is teardrop-shaped as shown in FIG. 8. Preferably, onearm28 includes a pair offingers30, and theother arm28 includes asingle finger30 havingtabs34 extending outwardly near the tapered end ofhole32.Tabs34 fit within and interlock withholes32 of the pair offingers30, to holdarms28 in a partially closed, compressed position, as shown in dashed lines in FIG. 7. This has been found to help in insertingrod16 throughholes32 when assemblingassembly10, particularly if this must be done afterneedle12 has been inserted intotissue100.
• In FIGS. 9 and 10,[0038]arms28 are shown squeezed together towardrod16, so that the enlarged portions ofholes32 overlap and limited or no contact occurs betweenrod16 and holes32. Thus the locking mechanism is unlocked, allowing free passage ofrod16 throughholes32. The inward movement ofarms28 is limited by the length offingers30, which are stopped by an opposingarm28 whenarms28 are squeezed toward one another to a fully squeezed position. Whenarms28 are not squeezed,rod16 is locked by the tapered portions ofholes32, as shown in FIGS. 11 and 12. This releasable locking mechanism provides sufficient holding force for the operation described above with respect to FIGS. 1, 4,5, and6. It is selectively actuable by the surgeon using very simple hand movements, and does not interfere with the surgeon's control of the placement ofneedle12 withinbody100.
• Holes[0039]32 include V-shaped locking surfaces formed as part of the teardrop-shape ofholes32, shown best in FIG. 8. These V-shaped locking surfaces are believed to provide reliable locking and unlocking performance oflock20, particularly in those embodiments in which oppositely biasedarms28 each include V-shaped locking surfaces, so that the opposing locking surfaces are forced in opposite directions by the spring ofarms28, each towardrod16 held withinneedle12. However, other shapes may be used with satisfactory results, and perhaps even with superior results. For example, holes32 may be round, oval, square or triangular, with or without a V-shaped or other taper in the locking surfaces relative to the movement ofhole32 with respect torod16. Furthermore, the size ofhole32 relative tofinger30 may be such that substantial locking, frictional contact is made withrod16 at both an unsqueezed and a fully squeezed position ofarm28, so thatrod16 may be locked in both the unsqueezed and squeezed positions ofarm28. Limited or no contact is made betweenrod16 andhole32 in an intermediate, unlocked position ofarm28.
• Other aspects of[0040]grip114 are identified in FIG. 7, including afunnel36 that acts as a guide for feedingseeds24 intoneedle12. The interconnection betweenfunnel36 andneedle12 is seen best in FIG. 11.Funnel36 also guidesblunt end26 ofrod16 when insertingrod16 intoneedle12.
• Also shown in FIG. 7 is a gripping[0041]texture38 formed onarms28, preferably corrugated. Finally, abushing40 provides a reinforcement for joininggrip114 toneedle12, and doubles as a plug for receiving aprotective sheath42, used when storing and handlingassembly10.Sheath42 preferably is at least as long, if not longer, thanneedle12, protecting against inadvertent punctures and injuries byneedle12.
• Referring again to FIG. 2,[0042]indicia44 formed ongrip14 provide a visual indication of the orientation ofpoint22 ofneedle12 relative to grip14. This is important because the unidirectionally taper formed by the sloped cut of the point tends to drive the point in a particular direction within abody100, relative to the long axis ofneedle12. A surgeon may use this tendency to positionneedle12 accurately within abody100.Indicia44 may simply be printed ongrip14, or, as shown in FIG. 2, may be formed with sufficient structural relief that indicia44 provides a tactile as well as a visual indication of orientation.
• The shape of[0043]grip14 shown in FIGS. 2, 13 and14 also helps a user ofassembly10 position needle within abody100. Relativelyflat surfaces46 provide a tactile indicator of the location of the point ofneedle12, or at least that the point is at 0-, 90-, 180-, or 270-degrees relative to aparticular surface46. The exact orientation is confirmed by feeling or looking atindicia44.Grip14 is formed with slightly roundedcorners48 that roll easily when gripped, allowing a surgeon to rotateneedle12 about its long axis, as shown in FIG. 14.
• Referring once again to FIG. 2,[0044]markings50 may be provided onneedle12, preferably in one-centimeter increments, with every five-centimeters marked or accented, as shown. Similar markings may be applied torod16.Bushing40 is shown to includeribs52 that help retainprotective sheath42, discussed above, and to includeindicia44.
• The foregoing description of the preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and many modifications and variations are possible in light of the above teaching. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined only by the scope of the issued claims.[0045]

Claims (27)

I claim:

1. A surgical needle comprising:

an outer tube;

an inner member slidingly fit within the outer tube; and

a lock mounted on the outer tube, wherein the lock selectively limits movement of the inner member relative to the outer tube in response to a squeezing or releasing of the lock.

2. The needle according toclaim 1, wherein:

the lock includes an arm biased outwardly relative to the inner member;

the arm includes at least one finger extending inwardly toward the inner member; and

the finger has a hole oversized relative to the inner member and through which the inner member extends, so that frictional forces may be exerted between the inner member and the finger when the arm is allowed to move outwardly to an unsqueezed position, and so that the frictional forces may be released by squeezing the arm toward the inner member.

3. The needle ofclaim 2, wherein the hole and finger are sized such that limited or no contact occurs between the finger and the inner member when the arm is squeezed toward the inner member.

4. The needle ofclaim 2, wherein the hole and finger are sized such that frictional contact with the inner member occurs when the arms are squeezed toward one another to a fully squeezed position, so that the inner member may be locked in both the unsqueezed position and the fully squeezed position of the arms.

5. The needle ofclaim 2, wherein the hole includes a surface that is approximately V-shaped.

6. A lock operatively connected to a hollow needle for holding a slidable inner member relative to the hollow needle, comprising a pair of opposing locking surfaces forced by a spring toward an inner member held within the hollow needle.

7. The lock ofclaim 6, wherein the spring is formed from outwardly extending resilient arms.

8. The lock ofclaim 7, wherein the locking surfaces are on fingers extending inwardly from the arms.

9. The lock ofclaim 8, wherein the locking surfaces are formed as part of holes on the fingers.

10. The lock ofclaim 9, wherein the holes and fingers are sized such that limited or no contact occurs between the locking surfaces and an inner member held within the tube, when the arms are squeezed toward one another to a fully squeezed position.

11. The lock ofclaim 9, wherein the holes and fingers are sized such that frictional contact with an inner member held within the tube occurs when the arms are squeezed toward one another to a fully squeezed position, so that an inner member may be locked in both the unsqueezed position and the fully squeezed position of the arms.

12. The lock ofclaim 8, wherein the locking surfaces are approximately V-shaped.

13. The lock ofclaim 8, further comprising a tab formed on at least one of the fingers, and wherein the tab interlocks with a hole on an opposing finger to hold the arms in a partially closed position.

14. The lock ofclaim 8, wherein the arms are outwardly biased.

15. The lock ofclaim 7, wherein the locking surfaces are approximately V-shaped.

16. The lock ofclaim 7, wherein the arms are outwardly biased.

17. The lock ofclaim 6, wherein the locking surfaces are approximately V-shaped.

18. A surgical tool for depositing material within living tissue, comprising:

a delivery tube for penetrating living tissue and delivering material to within living tissue;

an inner member held within the delivery tube to push material through the tube; and

a releasable lock operatively connected to the tube to selectively limit movement of the inner member relative to the tube.

19. The surgical tool ofclaim 18, wherein the lock includes outwardly biased arms.

20. The surgical tool ofclaim 19, wherein the lock includes locking surfaces formed on fingers extending inwardly from the arms.

21. The surgical tool ofclaim 20, wherein the locking surfaces are formed as part of holes on the fingers.

22. The surgical tool ofclaim 21, wherein the holes and fingers are sized such that limited or no contact occurs between the locking surfaces and the inner member, when the arms are squeezed toward one another to a fully squeezed position.

23. The surgical tool ofclaim 21, wherein the holes and fingers are sized such that frictional contact with the inner member occurs when the arms are squeezed toward one another to a fully squeezed position, so that the inner member may be locked in both the unsqueezed position and the fully squeezed position of the arms.

24. The surgical tool ofclaim 20, wherein the locking surfaces are approximately V-shaped.

25. The surgical tool ofclaim 20, further comprising a tab formed on at least one of the fingers, and wherein the tab interlocks with a hole on an opposing finger to hold the arms in a partially closed position.

26. The surgical tool ofclaim 18, wherein the lock includes a spring for holding the lock in a biased, locking position.

27. A maneuverable needle for insertion into living tissue comprising:

a delivery tube having a unidirectionally tapered point and a long axis extending along the tube;

a grip joined to the tube for rotating the tube about the long axis; and

a visual indicator formed on the grip to provide a visual indication of the orientation of the point relative to the grip.

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