STEERABLE AND FLEXIBLY CURVED PROBES
Steerable and flexibly curved probes are provided, primarily for surgical applications. A probe with flexible distal portion is inserted through an incision or cannula and the flexible distal portion may be selectively bent or steered using a guide wire. The guide wire is extended through the probe on a radially offset axis, and affixed at its distal end to the distal end of the flexible distal portion. The curvature of the nitinol wire is induced by extending or retracting the wire from the proximal end of the flexible distal portion while the distal end of the guide wire remains affixed to the distal end of the probe. The guide wire is activated by a finger-actuated mechanism. A further embodiment is provided in which the guide wire is fixed at both ends of the flexible distal portion of the probe and has a normally curved conformation, and assumes such conformation after insertion through a straight cannula. Other embodiments and applications are similarly disclosed.
This application claims the benefit of the filing date of U.S. Provisional Application No. 60/887,635 (“Steerable Intraocular Laser”), filed Feb. 1, 2007, and U.S. Provisional Application No. 60/887,921 (“Flexible Curved Intraocular Laser Probe”), filed Feb. 2, 2007. The entire respective disclosures of each of said provisional patent applications are hereby incorporated by reference herein.
BACKGROUND OF THE INVENTION1. Field of the Invention
The invention concerns insertable probes, primarily in the surgical field, which can be steered or redirected after insertion. Several embodiments of the invention are in the form of steerable or flexibly curved microsurgical laser probes for use primarily in ophthalmic surgery. However, the invention also relates to insertable probes generally and has non-medical applications, for example, to non-medical endoscopy and boroscopy.
2. Background of the Related Art
A wide variety of surgical and diagnostic methods involve the insertion of probes, catheters, endoscopes and other devices into interior spaces and passageways within human or animal organs.
In the ophthalmic field, for example, intraocular laser photocoagulation, or the process of forming a blood clot in the interior of the eye using a laser, is performed in many types of surgical procedures. Application of laser photocoagulation is commonly done with the aid of a probe that carries an optical fiber that can direct the laser light. The fiber optic directs the laser energy from the laser source into the eye to the site of the coagulation. A typical prior art laser probe is shown in
Although easy to manufacture, there are shortcomings associated with the prior art laser probe. Surgical requirements limit how a laser probe 101 of the prior art can be inserted into the eye. When a laser probe 101 is inserted around insertion site 107 of the eye, the guided output 104 from the laser probe 101 cannot reach far periphery area 108 of the eye because the crystalline lens 109 of the eye blocks the range of motion of the laser probe 101. In fact, the furthest peripheral point toward the lens that the prior art laser probe 101 can reach is coagulation site 106 as shown in
In attempts to overcome these shortcomings, several variations of the metal sleeve laser probe of the prior art are in the field. There are curved laser probes made with a fixed and curved metal outer sleeve. These types of probes solve the problem of letting its guided laser output reach the far periphery of the eye. But unfortunately these probes can be used only with great difficulty in modern small incision vitrectomy surgery using cannulae. The cannulae used in vitrectomy surgery are typically straight cannulae that limit the passage of any curved probe or instrument. Even if the surgeon manages to force a curved laser probe through the cannula, the removal of the curved probe from the eye often causes the undesired effect of the cannula being removed from the eye as well. Another variation of the prior art laser probe uses a straight metal sleeve surrounding a fiber optic contained in a second metal tube having a curved contour. During surgery the outer sleeve is retracted allowing the inner sleeve to adopt a curved contour. But again, this type of laser probe is difficult to manipulate during surgery. There are additional shortcomings with this type of laser probe. For one example, it can curve in only one direction. For a second example, to remove the probe from the eye, the second metal tube must be manually straightened, necessitating awkward motions on the part of the surgeon and placing the eye at risk of inadvertent injury.
Another shortcoming common to all three types of prior art laser probes described above is that all of these laser probes employ a rigid metal outer sleeve that is potentially traumatic to delicate intraocular structures. Inadvertent contact with the lens or retina in particular can lead to serious physiological consequences.
Accordingly, the current state of intraocular laser probes is suboptimal and there is a need for a laser probe in which the angle or curvature of the optical fiber can be easily and quickly varied by the surgeon at will. Moreover, a device that solves the problems described above would have applicability in many other types of surgical and diagnostic procedures which involve the insertion of probes and the like into interior spaces and passageways within body organs of humans or animals, as well as corresponding non-medical mechanical applications.
SUMMARY OF THE INVENTIONThe present invention addresses the above-noted shortcomings in the prior art by providing a steerable or flexibly curved instrument. In one embodiment, the instrument may be a probe that can be straight in its alignment while being inserted, such as through a cannula, but after insertion can adopt a curved shape upon manipulation by the operator so as to afford better access to interior areas that were not easily reached by a prior art devices.
In one embodiment, the probe comprises a tubular member providing an implement, for example, a surgical or diagnostic tool, at the distal end thereof. The tubular member is flexible along its axis and has at least one axial bore. A guide wire is disposed within the bore, such that the axis of the guide wire is radially offset from the axis of the tubular member. The guide wire is affixed to the tubular member at or near its distal end. The guide wire may be of a type, such as a nitinol wire, normally having a first lengthwise conformation (e.g., straight), and the property whereby it tends to return to said first lengthwise conformation after being deformed therefrom. In one embodiment, a fiber optic guiding the output of a laser source is also housed in the tubular member, so that the laser light exits the steerable probe at its distal end. Any other suitably sized implements, such as tools for performing a surgical operation, electrodes, sensors, imaging elements, etc., may be provided within and/or at the distal end of the probe; the probe itself may be adapted to hold the desired implement at or near its distal end.
Since the guide wire is affixed to or near the distal end of the probe, retracting the guide wire within the bore tends to make the probe curvedly deform in a transverse direction, such that (as a result of the radial offset of the guide wire as it runs through the tubular member) the guide wire will be situated on the inside of the radius of curvature of the probe (where the circumference is shorter). Similarly, extending the guide wire will tend to make the probe curvedly deform transversely in the opposite direction, i.e., such that the guide wire will be situated on the outside of the radius of curvature of the probe (where the circumference is longer). Thus, acting on the guide wire to extend or retract it in the bore provides a means of “steering” the probe.
In some embodiments, the radial offset of the guide wire within the tubular member is provided by having a separate, offset bore within the tubular member, for the guide wire. In other embodiments (for example small-gauge embodiments), the guide wire is radially offset but housed in the same bore as the optical fiber or other instrumentation fibers, cables or components (if any).
In other embodiments, a finger-actuated control within the handle actuates the slidable movement of the guide wire relative to the bore of the probe. Several possible embodiments of such a control are illustrated. In addition, various handle components are provided to hold the instrument and house the actuation controls.
In a further embodiment, the guide wire is provided in a normally curved (as opposed to straight) configuration, and is not slidably movable, but rather is fixed at both ends of the flexible tubular member. In this embodiment, the probe may, for example, be inserted through a straight cannula, by using minimal insertion force to transiently straighten it, and will then assume its naturally curved conformation after insertion, thus providing many of the advantages of the invention with a simpler apparatus than the other embodiments.
Further features and embodiments of the invention are illustrated by the accompanying drawings and further explained in the detailed description that follows.
The following is a description of several embodiments of various aspects of the invention. These embodiments are illustrative only. The invention is limited only by the scope of the claims that are appended hereto, and is by no means limited to particular examples described below.
The present invention is useful for many purposes. The anticipated field of use is generally referred to herein as “surgery.” However, the terms “surgery” and “surgical” should be understood in a broad sense, as also including diagnostic methods carried out internally, and related instruments, as well as minimally invasive procedures and instruments, or those employed through a small incision, such as in connection with catheterization and endoscopy. In addition, the invention is also adaptable to non-medical applications, such as non-medical endoscopy and boroscopy, and the use of the term “surgical” or like medical-related terms should not be understood as limiting the scope of the invention to medical applications.
An implement, for example a surgical or diagnostic tool, is situated at or near the distal end 204 of the tubular member 201. In the case of a steerable laser probe, optical fiber 202 is inserted lengthwise through the axial bore 205 of the tubular member 201 to provide a laser photocoagulator at distal end 204 (and in such a case, it will be understood that the distal end of the optical fiber, through which laser light is delivered, acts as the “implement”). Optical fiber 202 is typically comprised of a silica core with cladding and is preferably further coated with polyimide plastic coating to increase its resistance to breakage. (While this specification generally uses the term “optical fiber” to describe an optical conduit component in various embodiments, it will be understood that the term is intended to encompass any type of conduit, waveguide or fiber for transmitting electromagnetic energy, for example, multimode and singlemode fibers, as well as fiber optic cables comprised of a plurality of fibers.) Optical fiber 202 is also flexible. A wire member, referred to in this embodiment as a guide wire (203) is also inserted lengthwise through the axial bore 205 of the tubular member 201. The guide wire 203 is affixed to the tubular member at or near distal end 204. The proximal ends of both the guide wire 203 and the optical fiber 202 extend beyond the proximal end of the tubular member 201. Preferably, the guide wire 203 is provided in a form such that it is normally in a straight conformation. However, the guide wire 203 is flexible so that when a bending force is applied to it, the wire 203 will curvedly deform and have a curvature in accordance with the force. Once the force is removed, the guide wire 203 will tend to spring back to its normal straight conformation.
In the embodiment described above, guide wire 203 is made of nitinol. However, guide wire 203 may be any type of wire member, that is, any generally lengthwise-extended structure made of any material that is bendably flexible and resistant to tensile and compressive stress, that can be formed into a wire or cable shape. In some applications, it is desirable that this material exhibit the property of tending to return to a first conformation after being deformed from that conformation, but this property is not essential in other applications (in some applications, a degree of hysteresis may in fact be desirable). A plastic optical fiber (or other similar fiber optic) can bend at the distal tip and can also serve as such a guide wire. The advantage of the fiber optic is that it can also be used to bring light into the eye. This would provide a lighted laser probe. Treatments such as shaping the distal end of the fiber optic could help control the distribution of light emanating from the tip of the illumination fiber. Thus, the angular spread of light leaving the fiber optic delivering light could be different from the cone angle of laser light leaving the laser fiber optic. A fiber delivering light can be of the same composition as the laser fiber, namely silica fiber with polyimide cladding. Silica fiber with polyamide cladding costs much more per meter than does plastic optical fiber, and for simple delivery of light plastic optical fiber suffices. For purposes of this disclosure, and the claims, the term “wire member” is defined to include any structure as discussed in this paragraph.
The steering capability of the present invention is shown in
To examine this action in further detail, we will refer again to
Thus, by exerting an axial force on wire 203, the slidable movement of the wire 203, coupled with its affixation at the distal end 204, creates a controllable transverse curved deformation of the guide wire 203 and tubular member 201. This curved deformation creates a range of steerable motion for distal end 204—wherein the precise location of the distal end 204 depends on the magnitude and direction of the forces 207 and 208. Furthermore, the proximal end of tubular member 201 may be kept straight while its distal end is being laterally moved. If inserted, for example through a cannula, the assembly may be rotated axially within the cannula (with the distal end also movable transversely, as above), to provide an additional degree of control to the instrument (and in addition, the distance of insertion can also be varied). Any implement, in one embodiment a laser photocoagulator, disposed at the distal end 204 of the instrument will be provided with a corresponding range of steerable motion.
In
A probe in accordance with the present invention, in numerous embodiments, can be used in vitrectomy surgery. Vitrectomy surgery can be performed with various sizes of instruments, for example, 20 gauge instruments, or 0.9 millimeter diameter, 23 gauge instruments, or 0.62 millimeter diameter, or 25 gauge instruments, or 0.5 millimeter diameter, or even smaller gauge instruments down to a diameter of about 0.25 mm. This means, for example, that in surgeries using 20 gauge instruments, the diameter of the tubular member cannot exceed about 0.9 millimeters. The twin axial bore configuration shown in
In
Housing 521 is shown in detail, in axial cross-section, in
In yet another actuator embodiment, as shown in
A further feature is provided with respect to this third actuator embodiment. Due to the length of the guide wire 503g from the distal end of the boss 518g, at 520g, to the point of affixation to receiving member 541g, guide wire 503g may buckle in this span. This creates a problem because if guide wire 503g buckles in this span, then the levered rotation of receiving element 541g will not cause the guide wire 503g to slidably extend or retract, and in turn the guide wire 503g will not curvedly deform the tubular member 50g as desired. The solution to this problem is to house the guide wire 503g in hollow reinforcement tubing 531. The reinforcement tubing 531 is also held by compression by threaded shaft 540g, acting as a set screw in receiving element 541g. Because curvedly deforming the guide wire 503g within tubular member 50g by the operation of actuator 414g does not require much force, there is no significant bending moment in the reinforcement tubing 531.
In each of the above-described actuation embodiments (referring to
As shown in
Because a surgical or diagnostic instrument, such as the output end of a laser photocoagulator, is situated at or near the distal end of the tubular member 501, the instrument can be directed as the tubular member is steered as described above. As configured in this embodiment, the distal end of the tubular member 501 is capable of curving more than 100 degrees in each direction, allowing nearly complete laser photocoagulation of the retina by placing the instrument through one sclerotomy opening in the eye. Because (in this particular embodiment) the guide wire 503 was selected to be statically straight such that it will only deform when a force is applied to it, releasing the finger pad 515 causes the guide wire 503 and in turn the tubular member 501 automatically to straighten. This is advantageous because the natural straight position can be assumed when the instrument first enters the eye, as insertion of an object is easier if done normal to the surface. Also if a cannula system is used during the surgery, the steerable probe is more easily inserted if straight because the cannula is straight. Thus, when the surgeon is first inserting the steerable probe of the present invention into the eye or a cannula, he need not exert any forces upon finger pad 515. After the tubular member 501 is inserted into the eye, a surgeon, by operating finger pad 515, can steerably curve the tubular member 501 to avoid obstruction internal in the eye as the crystalline lens, and more precisely position the instrument.
Those skilled in the art will appreciate, upon reading the foregoing, that a probe in accordance with any of the embodiments of the present invention overcomes the limitations of the prior art. First, a probe in accordance with the present invention, either statically curved or dynamically steerably curved, can curve around internal obstructions such as the crystalline lens of the eye and allow the probe to have direct lines of access to all peripheral areas of the internal wall of the eye. Second, in case where the probe is used as a laser photocoagulator, by allowing the probe to have direct lines of access, the laser output emitting from the instrument can be directed to impinge upon the coagulation site of the eye at a normal angle of incidence, thus maximizing the intensity of the laser energy at the coagulation site. Third, unlike prior art probes that employ a rigid metal outer sleeve, the probes of the present invention employ a tubular member composed of a biocompatible, plasticizer free thermoplastic material, which may more safely be moved near delicate internal structures of the eye.
In addition, steerable and curved probes as described herein may be readily used and adapted for use in other types of surgical and diagnostic procedures, such as cardiovascular, gastrointestinal and other types of surgery and diagnostic methods in which it an instrument is introduced or threaded trough an opening or passageway and a mechanism is desirable to direct or steer the instrument after its introduction.
The foregoing summary, drawings, and detailed descriptions describe various embodiments of the invention and the principles by which the invention operates, and show the advantages that the invention provides over previous solutions. It is believed that the invention has been explained in sufficient detail to enable persons of ordinary skill in the field who study this disclosure to practice the techniques shown, as well as other variations and embodiments within the spirit of the invention that suit their individual needs. Accordingly, the specific features of the invention are not intended to limit the scope of the invention, as defined in the following claims.
Claims
1. A steerable probe comprising:
- a) a flexible tubular member providing a position for holding an implement at or near the distal end thereof, said flexible tubular member being flexible along its longitudinal axis and having at least one longitudinal axial bore extending from its proximal end to its distal end;
- b) a wire member extending lengthwise through the length of said at least one axial bore, wherein i. said wire member has the properties of being flexible in a bending mode and resistant to tensile and compressive stress, ii. said wire member is disposed within said at least one axial bore such that the longitudinal axis of said wire member is substantially parallel to but radially offset from the longitudinal axis of said flexible tubular member, iii. the distal end of said wire member is securely affixed to or near the distal end of said flexible tubular member; and iv. the proximal end of said wire member is slidably movable in the axial direction with respect to said at least one axial bore, so as to be extendable and retractable relative to said at least one axial bore,
- wherein said slidable movement, radially offset disposition and affixation causes said wire member to curvedly deform so as to be situated on the inner circumference of said flexible tubular member when said slidable movement acts to retract said wire member relative to said at least one axial bore, and to be situated on the outer circumference of said flexible tubular member when said slidable movement acts to extend said wire member relative to said at least one axial bore.
2. A probe assembly comprising
- a) the steerable probe of claim 1, and
- b) a handle comprising a proximal boss and a rigid tubular member at the distal end thereof, said rigid tubular member being attached at its distal end to the proximal end of said probe,
- wherein, the wire member internal to said steerable probe extends through said rigid tubular member and into said boss.
3. The probe assembly of claim 2 further comprising an actuator mounted within said boss, said actuator being attached to said wire member and being operable to extend and retract said wire member with respect to the at least one axial bore internal to said probe.
4. The probe assembly of claim 3 wherein said actuator comprises a mechanical element secured to a section of said wire element and slidable in a space provided within said boss in a direction generally aligned with the axis of said axial bore.
5. The probe assembly of claim 3 wherein said actuator comprises a class 2 lever having a fulcrum at its distal end, said fulcrum being affixed to said boss such that said lever is movable in a plane approximately aligned with said probe, an input location for movement of said lever at its proximal end, and an attachment to said wire member at a point intermediate said input location and said fulcrum.
6. The probe assembly of claim 3 wherein said actuator is activated through a finger pad protruding externally to said boss.
7. A probe in accordance with claim 1 further comprising a surgical or diagnostic implement provided at the distal end thereof.
8. A probe in accordance with claim 7, wherein said surgical or diagnostic implement is an optical fiber adapted to emit light from the distal end of said probe.
9. A probe assembly in accordance with claim 2, further comprising a surgical or diagnostic implement provided at the distal end thereof.
10. A probe assembly in accordance with claim 9, wherein said surgical or diagnostic instrument is an optical fiber adapted to emit light from the distal end of the flexible tubular member of said probe assembly.
11. A steerable laser photocoagulator comprising
- a) a probe assembly in accordance with claim 3,
- b) an optical fiber, positioned in said probe assembly to have a distal terminus at or near the distal end of said flexible tubular member, disposed at or near said distal end so as to be able to output light from said distal end, and extending longitudinally through said flexible tubular member and said rigid tubular member and at least into said boss, and
- c) a laser light source coupled to the proximal end of said optical fiber.
12. A steerable laser photocoagulator in accordance with claim 11 wherein, within said boss, said optical fiber traverses said actuator by passing through a passage mechanically isolated from the movement of said actuator.
13. The steerable laser photocoagulator of claim 12 where said passage is a passage through the structure of said actuator.
14. A probe in accordance with claim 1 wherein said wire member has the further property of tending to return to a first lengthwise conformation after being bendably deformed therefrom.
15. A probe assembly in accordance with claim 14 wherein said wire member comprises a nitinol wire.
16. A probe in accordance with claim 1 wherein said wire member is composed of a material that will transmit light illumination.
17. A probe in accordance with claim 16 wherein said wire member comprises a plastic optical fiber.
18. A probe in accordance with claim 8, wherein said optical fiber comprises silica optical fiber.
19. A probe in accordance with claim 18, wherein said silica optical fiber is cladded and the core diameter of said silica optical fiber including cladding is in the range of about [50] to 250 microns.
20. A probe in accordance with claim 19 wherein the core diameter of said silica optical fiber including cladding is about 100 to 120 microns.
21. A probe in accordance with claim 18, wherein said optical fiber has an exterior coating.
22. A probe in accordance with claim 21 wherein said exterior coating is made of a composition comprising polyimide.
23. A probe in accordance with claim 1 comprising at least two longitudinal axial bores, the first of which carries said wire member and the second of which is in communication with a surgical or diagnostic implement provided at the distal end of said probe.
24. A probe in accordance with claim 23 wherein said second bore carries an optical fiber.
25. A probe in accordance with claim 22, further comprising at least two longitudinal axial bores, the first of which carries said wire member and the second of which is in carries said optical fiber, wherein said wire member has a diameter of about 0.005 inches, the first said longitudinal axial bore has a diameter of about 0.006 inches and the second said longitudinal axial bore has a diameter of about 0.007 inches.
26. The probe of claim 1, wherein said flexible tubular member has a range in diameter from about 0.25 millimeters to about 0.9 millimeters.
27. The probe of claim 1, wherein said flexible tubular member is made of a composition comprising a polymer.
28. The probe of claim 27 wherein said polymer comprises PVC.
29. The probe of claim 27, wherein said polymer comprises polyether block amides.
30. The probe assembly of claim 5 wherein said class 2 lever is affixed to said wire element with a compressive fastener and further comprising a housing surrounding said wire member, said housing comprising a length of reinforcement tubing between said lever and the distal exit point of said wire member from said boss.
31. The probe assembly of claim 30, wherein said reinforcement tubing is also secured to said class 2 lever by said compressive fastener.
32. A flexible probe comprising:
- a) a flexible tubular member providing a position for holding an implement at or near the distal end thereof, said flexible tubular member being flexible along its longitudinal axis and having at least one longitudinal axial bore extending from its proximal end to its distal end;
- b) a wire member extending lengthwise through the length of said at least one axial bore, wherein i. said wire member has a property whereby said wire member tends to return to a first lengthwise conformation after being deformed therefrom, ii. the longitudinal axis of said wire member is substantially parallel to said longitudinal axis of said flexible tubular member, iii. the distal end of said wire member is securely affixed to or near the distal end of said flexible tubular member; and
- iv. the proximal end of said wire member is securely affixed to or near the proximal end of said flexible tubular member,
- wherein said tubular member may be deformed from said first lengthwise conformation in one step of a surgical or diagnostic procedure and then without intervention return to said first lengthwise conformation.
33. A flexible probe in accordance with claim 32 wherein said first lengthwise conformation is a curved conformation, said tubular member may be deformed from said straight conformation for insertion through an incision or cannula, and will resume said first lengthwise curved conformation after passing beyond said incision or cannula upon such insertion.
34. A flexible probe in accordance with claim 33 wherein the radius of said curved conformation is in the range of 15-45 mm.
35. The flexible probe of claim 34 wherein said radius is approximately 18 mm.
36. A flexible probe assembly comprising:
- a) a flexible probe in accordance with claim 32, and
- b) a handle comprising a proximal boss and a rigid tubular member at the distal end thereof, said rigid tubular body being attached at its distal end to the proximal end of said probe.
37. A method for performing a surgical or diagnostic procedure using a probe assembly in accordance with claim 2, comprising
- a) inserting said probe assembly through an incision or cannula,
- b) actuating said wire member so as to induce the desired curvature of said probe, and
- c) rotating said probe about its longitudinal axis so as to point the distal end of said probe in the desired direction.
38. A method for performing a surgical or diagnostic procedure using a probe assembly in accordance with claim 33, comprising
- a) inserting said probe assembly through an incision or cannula to a sufficient insertion distance such that the flexible tubular member thereof assumes said first longitudinal curved conformation, and
- b) rotating said probe about its longitudinal axis so as to point the distal end of said probe in the desired direction.
39. A method for performing a surgical or diagnostic procedure using a probe assembly in accordance with claim 3, wherein the first lengthwise conformation of said wire member is a straight conformation, said method comprising (a) inserting said probe and operating said probe in a curved configuration by actuating the linkage recited in claim 3, and (b) later returning said probe to a straight configuration by releasing said linkage.
Type: Application
Filed: May 30, 2007
Publication Date: Aug 7, 2008
Inventor: Richard Spaide (New York, NY)
Application Number: 11/755,025
International Classification: A61N 5/067 (20060101);