WO1996039956A1

WO1996039956A1 - Surgical instrument with flexible drive shaft

Info

Publication number: WO1996039956A1
Application number: PCT/US1996/008106
Authority: WO
Inventors: Gilbert M. Aust; Timothy E. Taylor
Original assignee: Aust & Taylor Medical Corporation
Priority date: 1995-06-07
Filing date: 1996-05-30
Publication date: 1996-12-19

Abstract

A flexible drive shaft for a medical tool to be used within a body is characterized by a thin-walled, hollow, tubular shaft having a distal end and a proximal end. The proximal end is suitable for attachment to a rotatable driver. The hollow tubular shaft defines a bore (128a). A spring wire extension (230b) has a proximal end and a distal end. The proximal end is operatively connected to the distal end of the tubular shaft, preferably by high energy welding. The spring is flexible through an angle greater than 90° to the axis of the tubular shaft while maintaining an internal path through the withdrawal of tissue. The path is sized substantially equal to the bore of the tubular shaft. The spring wire extension permits a tool (124) to be carried by the distal end of the spring wire extension, whereby rotary motion applied to the drive shaft by a rotatable driver can be transmitted to a tool carried by the spring wire extension.

Description

SURGICAL INSTRUMENT WITH FLEXIBLE DRIVE SHAFT

Background of the Invention Field of the Invention This invention relates generally to an arthroscopic/endoscopic surgical instrument, and more particularly to arthroscopic/endoscopic surgical instrument which has a flexible drive shaft incorporating a spring, which may be used to remove tissue from a joint or other body space. Description of the Prior Art

Various types of orthopaedic surgical procedures, particularly large joint procedures, are performed by arthroscopic techniques. An endoscope and a working tool are employed to perform a minimally invasive procedure thus allowing shorter patient recovery time and lower hospital stay costs . Typically a fiberoptic endoscope is inserted in the area of concern and other working tools such as shavers, probes and baskets are used to remove, reshape and adjust certain anatomical deficiencies. Flexible fiberoptic scopes have been developed in recent years, thereby providing the surgeon with the ability to change viewing areas. Working tools have been developed which have fixed angles and deflectors. Recently, tools have been developed which are articulating and flexible, such as U.S. Patent Application Ser. No. 08/008,670 filed January 25, 1993 entitled SURGICAL INSTRUMENT by Dr. Gilbert M. Aust and Timothy E. Taylor. The surgical instrument described in the aforementioned patent application utilizes a flexible drive shaft which is made out of a polymeric material.

Other surgical instruments, for substantially different purposes, do utilize a flexible coil. Such devices are shown in U.S. Patent Nos. 5,108,411 and 5,287,858. In these two patents, flexible drives are utilized which incorporate a spring ir.to their drive. However, such instruments are used in a body lumen and further there are no provisions for evacuating material thru the central portion of the instrument. There is no structure which allows for evacuated material to be withdrawn.

The present invention addresses the problems associated with the prior art and provides for a steerable and flexible drive shaft for a medical tool which utilizes a spring wire extension, or flexible portion, and allows for evacuation of material thru the spring's internal path. Summary of the Invention

The present invention is a flexible drive shaft for a medical tool to be manipulated within the human body. The drive shaft has a thin-walled, hollow, tubular shaft having a distal end and a proximal end. The proximal end is suited for attachment to a rotatable driver. The hollow tubular shaft defines a bore. A spring wire extension has a proximal end and a distal end. The proximal end is operatively connected to the distal end of the tubular shaft. The spring is flexible through an angle greater than 90° to the axis of the tubular shaft while maintaining an internal path for the withdrawal of tissue. The path is sized substantially equal to the bore of the tubular shaft. The spring wire extension permits a cutting tool to be carried by the distal end of the spring wire extension. Rotary motion, which is applied to the drive shaft by the rotatable driver, can be transmitted to a tool carried by the spring wire extension. In a preferred embodiment, the spring wire extension is high-energy welded to the tubular shaft.

Brief Description of the Drawings Fig. 1 is a schematic illustration of a surgical instrument constructed in accordance with the present invention; Fig. 2 is a schematic sectional view, taken generally along the line 2-2 of Fig. 1, illustrating the manner in which a known handle is connected with a tubular stem section of the surgical instrument;

Fig. 3 is an enlarged schematic sectional view depicting the manner in which an actuator for bending an articulated section of the surgical instrument is mounted on the stem section and the manner in which a drive shaft is connected with a tubular drive element which extends through the stem section;

Fig. 4 is an enlarged schematic side elevational view depicting the construction of an articulated section of the stem section;

Fig. 5 is a schematic plan view, taken generally along the line 5-5 of Fig. 4, further illustrating the construction of the articulated section of the stem section;

Fig. 6 is a highly schematicized illustration depicting the manner in which a pair of wires are connected with an actuator assembly which tensions one of the wires to bend the articulated section of the stem section;

Fig. 7 is an enlarged schematic side elevational view, generally similar to Fig. 4, illustrating the manner in which the articulated section is flexed by the actuator assembly of Fig. 6; Fig. 8 (on sheet 4 of the drawings) is a highly schematicized illustration depicting deflection of the articulated section in either one of two directions by the actuator assembly of Fig. 6 and depicting the manner in which the articulated section is free to move in either one of two transverse directions; and

Fig. S ( on sheet 2 of the drawings) is a fragmentary schematic illustration depicting an embodiment of the invention in which the articulated section can be flexed in any one of four directions by an actuator system. Figure 10 is an enlarged view of another embodiment of a drive shaft.

Figure 11 is a cross-sectional view of the drive shaft of Figure 10, taken generally along the lines 11-11.

Figure 12 is a cross-sectional view of the drive shaft of Figure 10, taken generally along the lines 12-12.

Description of Specific Preferred Embodiments of the Invention

General Description

The flexible drive shaft of the present invention may be utilized in a variety of environments.

It may be used within a fixed precurved tube of a fixed radius or it may be used in a articulated section as will be more fully described hereafter.

A surgical instrument 20, constructed in accordance with the present invention, is illustrated in Fig. 1 and may be used during the performance of arthroscopic and/or endoscopic surgery. A control apparatus 22 is connected with the surgical instrument 20 through a cord system 24. The surgical instrument 20 includes a handle 28 of known construction, which is connected with a tubular stem section 30. An instrument 32 of choice, e.g. a shaver, is connected with a rigid portion 33 of the stem section by an articulated section 34 constructed in accordance with the present invention. In accordance with one of the features of the present invention, an actuator assembly 38 is manually operable to bend the articulated section 34 to move the instrument 32 between any one of many positions relative to the rigid portion 33 of the stem section 30. The actuator assembly 38 can be operated to bend the articulated section 34 from a straight or initial condition shown in Figs. 4 and 5 to any one of a plurality of bent conditions, some of which have been indicated schematically in Fig. 7. Thus, the actuator assembly 38 can be operated to bend the articulated section 34 upwardly from the straight' or initial orientation (shown in solid lines in Figs. 4, 5 and 7) through a plurality of positions, indicated in dashed lines and dash-dot lines to a fully flexed position indicated in dash-dot-dot lines in Fig. 7.

Of course, operation of the actuator assembly 38 could be interrupted with the instrument 32 in any one of the positions illustrated in Fig. 7 or in positions intermediate the positions shown in Fig. 7. In addition, the actuator assembly 38 can be operated to deflect the articulated section 34 downwardly (as viewed in Figs. 4 and 7) to any one of a plurality of positions. When the actuator assembly 38 has been operated to bend the articulated section 34 downward to a fully deflected position, the instrument 32 will extend straight downwardly in much the same manner as in which the instrument has been shown extending straight upwardly in dash-dot-dot lines in Fig. 7. Thus, the actuator assembly 38 is operable to bend the articulated section 34 and to move the instrument 32 relative to the rigid portion 33 of the stem section 30 in such a manner as to change the orientation of the instrument 32 through 90° to either a straight upward orientation (as shown in dash-dot-dot lines in Fig. 7) or to a straight downward orientation.

In accordance with another feature of the embodiment of the invention illustrated in Figs. 1-8, the articulated section 34 can be freely bent or deflected sidewardly, that is either up or down as viewed in Fig. 5 or into and out of the sheet as viewed in Figs. 4 and 7. Although the actuator assembly 38 is operable to positively deflect or bend the articulated section either up or down as viewed in Fig. 4, the articulated section 34 is allowed to float or bend sidewardly under the influence of forces applied to the articulated section. The actuator assembly 38 can be operated to change the orientation of the instrument 32 relative to the rigid portion 33 of the stem section 30 and body tissue during an operation. The actuator assembly 38 can be operated to positively change the orientation of the instrument 32 through a range of 90° or more. It may move upwardly (as viewed in Figs. 4 and 7) from the straight initial orientation and downwardly (as viewed in Figs. 4 and 7) from the straight initial orientation. In addition, the articulated section 34 can be deflected or bent under the influence of forces applied to the instrument 32, to either side of the straight initial orientation shown in Figs. 4 and 5.

It is believed that the surgical instrument 20 will be particularly advantageous for removing tissue from between vertebra in the human spinal column during an operation. Thus, the instrument 32, articulated section 34 and part of the rigid portion 33 of the stem section 30 can be inserted through a very small opening in the skin adjacent to the spinal column of a patient. As this is done, the articulated section 34 is straight in the initial orientation shown in Figs. 1, 4 and 5.

After the stem section 30 has been partially inserted through an opening in the skin adjacent to the spinal column, the actuator assembly 38 is operated to bend the articulated section 34 and move the surgical instrument 32 transversely to a longitudinal central axis of the rigid portion 33 of the stem section 30. This enables the instrument 30 to be moved to a desired position to engage tissue located between adjacent vertebra. As the instrument 32 is being moved by operation of the actuator assembly 38, the articulated section 34 can also be deflected sideways under the influence of forces applied against the instrument 32. Of course, the surgical instrument 20 can be used during the performance of many different types of arthroscopic and/or endoscopic operations. During use of the surgical instrument 20, it is contemplated that it will be desirable to convey tissue removed from between vertebra or other locations away from the instrument 32. Accordingly, a suction pump (not shown) is connected with the handle 28 at a connection 44. Suction is conducted through a central conduit or passage 45 (Figs. 3 and 4) in the stem section 30 to the instrument 32. The suction draws or pulls tissue from the area immediately adjacent to the instrument 32 back through the stem section 30 to the connection 44 and suction conduit.

In addition, water or other fluid can be utilized to irrigate the area where tissue is removed by the instrument 32. Articulated Section

The articulated section 34 includes a plurality of relatively movable sections 50, 52, 54 and 56 (Figs. 4 and 5) . The sections 50, 52, 54 and 56 are interconnected for pivotal movement about perpendicular axes. Thus, the section 50 is pivotal relative to the section 52 about a vertical axis indicated at 60 in Fig. 4. The section 50 is connected with the section 52 at pivot connections 62 and 64. Similarly, the section 54 is pivotal relative to the section 56 about a vertical axis indicated at 66 in Fig. 4. The section 54 is connected with the section 56 at pivot connections 68 and 70.

The section 52 is pivotal relative to the section 54 about a horizontal a: s indicated at 72 in Fig. 5. The section 52 is connected with the section 54 at pivot connections 74 and 76. Similarly, the section 56 is pivotal relative to an end portion 78 of the rigid stem section 33 about a horizontal axis indicated at 82 in Fig. 5. The section 56 is connected with the rigid portion 33 of the stem section 30 at pivot connections 84 and 86. The instrument 32 is pivotal relative to the section 50 about a horizontal axis indicated at 92 in Fig. 5. The instrument 32 is connected with the section 50 at pivot connections 94 and 96. The axes 60 and 66 (Fig. 4) extend parallel to each other and perpendicular to a longitudinal central axis of the stem section 30. Similarly, the axes 72, 82 and 92 (Fig. 5) extend parallel to each other and perpendicular to a longitudinal central axis of the stem section 30. The axes 60 and 66 extend perpendicular to the axes 72, 82 and 92. The axes 60, 66, 72, 82 and 92 all intersect the central axis of the stem section 30.

Initial operation of the actuator assembly 38 is one direction pivots the instrument 32 upwardly (as shown in Fig. 7) from the initial position shown in solid lines to the deflected position shown in dashed lines. Movement of the instrument 32 from the initial position shown in solid lines to the deflected position shown in dashed lines, is accomplished by pivotal movement of the instrument about the axis 92 at the pivot connections 94 and 96 (Fig. 5) .

Continued operation of the actuator assembly 38 pivots the sections 50 and 52 together while the instrument 32 is maintained in a deflected position. Thus, the sections 50 and 52 pivot upwardly from the initial position shown in solid -lines in Fig. 7 to the position shown in dash-dot lines in Fig. 7. As this occurs, the sections 50 and 52 pivot about the axis 72 (Fig. 5) at the pivot connections 74 and 76. During this movement, the orientation of the instrument 32 relative to the section 50 remains constant.

Continued operation of the actuator assembly 38 pivots the sections 54 and 56 upwardly (as viewed in Fig. 7) from the initial position shown in solid lines to the position shown in dash-dot-dot lines. The instrument 32 and sections 50 and 52 are maintained in the same orientation relative to each other during this pivotal movement of the sections 54 and 56. Thus, continued operation of the actuator assembly 38 pivots the sections 54 and 56 about the axis 82 (Fig. 5) at the pivot connections 84 and 86. During deflection of the articulated section

34 about the axes 72, 82 and 92 (Fig. 5) by operation of the actuator assembly 38, the articulated section 34 is also free to deflect sideways under the influence of forces applied against the articulated section. Thus, the section 50 and the instrument 32 are pivotal sideways relative to the section 52 about the axis indicated at 60 in Fig. 4. The section 50 is pivotal sideways at the connections 62 and 64. The sections 50, 52 and 54 are pivotal sideways relative to the section 56 about the axis indicated at 66 in Fig. 4. The section 54 is pivotal sideways at the connections 68 and 70.

Actuator Assembly The actuator assembly 38 includes a pair of flexible wires 102 and 104 (Figs. 6 and 7) which are connected with the instrument 32 through the tubular stem section 30. The wire 102 is connected with the upper (as viewed in Fig. 7) portion of the instrument 32 while the wire 104 is connected with the lower portion of the instrument 32. The wires 102 and 104 are offset from the pivot connections 94 and 96 (Figs. 5 and 7) . Tension in the upper wire 102 (as viewed in Fig. 7) is effective to pivot the instrument 32 in a clockwise direction about the pivot connections 94 and 96. Similarly, tension in the lower wire 104 is effective to pivot the instrument 32 in a counterclockwise direction (as viewed in Fig. 7) about the pivot connections 94 and 96. When the actuator assembly 38 (Fig. 6) is operated in one direction, the wire 102 shortens slightly and the wire 104 is lengthened to pull the instrument 32 from the initial position shown in solid lines to the position shown in dashed lines in Fig. 7. Once the instrument 32 reaches the position shown in dashed lines in Fig. 7, further shortening of the wire 102 and lengthening of the wire 104 by operation of the actuator assembly 38 pulls the sections 50 and 52 in a clockwise direction (as viewed in Fig. 7) from the initial position shown in solid lines to the position shown in dash-dot lines in Fig. 7. As this occurs, the section 52 pivots about the axis 72 at the connections 74 and 76.

Continued operation of the actuator assembly 38 continues to shorten the wire 102 and lengthen the wire 104. This results in the sections 54 and 56 being pulled in a clockwise direction (as viewed in Fig. 7) from the initial position shown in solid lines to the position shown in dash-dot-dot lines. As this occurs, the sections 54 and 56 pivot about the axis 82 (Fig. 5) at the connections 84 and 86. Operation of the actuator assembly 38 in the opposite direction is effective to shorten the wire 104 and lengthen the wire 102. As the actuator assembly is operated in the opposite direction to shorten the wire 104, the instrument 32 is pivoted downwardly or in a counterclockwise direction (as viewed in Fig. 7) about the axis 92 (Fig. 5) at the connections 94 and 96.

Continued operation of the actuator assembly 38 results in further lengthening of the wire 102 and shortening of the wire 104. This results in the sections 50 and 52 being pivoted downwardly or in a counterclockwise direction (as viewed in Fig. 7) about the axis 72 at the pivot connections 74 and 76. Still further operation of the actuator assembly 38 to lengthen the wire 102 and shorten the wire 104 results in the sections 54 and 56 pivoting downwardly or in a counterclockwise direction (as viewed in Fig. 7) about the axis 82 at the connections 84 and 86 (Fig. 5) . Thus, the articulated sections 34 can' be deflected or bent either upwardly, in the manner shown in Fig. 7, or downwardly depending upon the direction of operation of the actuator assembly 38. The actuator assembly 38 has been shown schematically in Fig. 6. The actuator assembly 38 includes a pair of pulleys or drums 108 and 110 to which end portions of the wires 102 and 104 are connected. The wires 102 and 104 are wound in opposite directions about the drums 108 and 110. The drums 108 and 110 rotate together about a common axis. Therefore, when one of the wires 102 or 104 is wound onto a drum 108 or 110, the other wire is unwound from the other drum.

Upon pivotal movement of a handle 114, a gear train 116 is actuated. The gear train 116 has been illustrated schematically in Fig. 3. The gear train 116 includes a gear 118 which is fixedly connected with the handle 114 and a gear 120 which is fixedly connected with the pulleys or drums 108 and 110 (Fig. 6) . Upon pivotal movement of the lever 114 toward the left or in a counterclockwise direction as viewed in Fig. 3, the gear 120 and drums 108 and 110 (Fig. 6) are rotated in a clockwise direction. This results in the wire 102 being wound onto the drum 108 and the wire 104 being unwound from the drum 110. As was previously explained, shortening or winding up of the wire 102 results in the instrument 32 being pivoted upwardly or in a clockwise direction as viewed in Fig. 7.

Continued operation of the actuator assembly 38 results in continued shortening or winding up of the wire 102 and lengthening or unwinding of the wire 104 until the instrument 32 has been moved through 90° from the original orientation shown in solid lines in Fig. 7 to the deflected orientation shown in dash-dot-dot lines in Fig. 7. Since the wire 104 is wound around the drum 110 in the opposite direction from the direction in which the wire 102 is wound around the drum 108, the wire 104 is lengthened as the wire 102 is shortened.

Pivotal movement of the handle 114 in a clockwise direction (as viewed in Fig. 3) rotates the gear 120 and drums 108 and 110 (Fig. 6) in a counterclockwise direction. This results in the wire 104 being wound onto the drum 110 as the wire 102 is wound off of the drum 108. Shortening of the wire 104 and corresponding lengthening of the wire 102 results in the articulated section 34 being pivoted downwardly or in a counterclockwise direction as viewed in Fig. 7 in the manner previously explained.

It should be understood that although one specific preferred embodiment of the actuator assembly 38 has been illustrated schematically and described herein, it is contemplated that the actuator assembly 38 could have a somewhat different construction if desired. Thus, many different types of mechanisms could be provided lengthening one of the wires 102 or 104 while simultaneously shortening one of the wires.

Regardless of the type of actuator assembly 38 which is utilized to deflect or bend the articulated section 34, the actuator assembly is operable to apply force to the articulated section to deflect the articulated section from a straight initial configuration to an upwardly or downwardly (as viewed in Fig. 7) bent configuration. Thus, upon operation of the actuator assembly 38, the articulated section 34 can be deflected in the manner shown in dashed, dash-dot and dash-dot-dot lines in Fig. 7. This will result in the instrument 32 being moved upwardly from a position in which it is aligned with a horizontal Z axis (Fig. 8) to a position in which it is aligned with a vertical Y axis. The Z axis is coincident with a longitudinal central axis of the rigid portion 33 of the stem section 30. The actuator assembly 38 can also be operated to bend or deflect the articulated section 34 to move the instrument 32 downwardly from the Z axis into alignment with the Y axis in the manner shown in dashed lines in Fig. 8. At this time, the instrument 32 extends downwardly from and perpendicular to the X and Z axes.

The actuator assembly 38 is operable to deflect the articulated section 34 to move the instrument 32 in either one of two directions, that is upwardly or downwardly as viewed in Figs. 7 and 8. However, the articulated section 34 is deflectable to enable the instrument to be moved sidewardly. Thus, the articulated section 34 can be moved, under the influence of external or sidewards forces applied against the instrument 32, to move the instrument from the initial position toward the left into alignment with the X axis as shown in dash-dot lines in Fig. 8. Similarly, the instrument 32 can be deflected toward the right (as viewed in Fig. 8) into alignment with the X axis in the manner shown in dash-dot-dot lines. By a combination of operation of the actuator assembly 38 and sideward deflection of the instrument 32, the articulated section 34 can be deflected in such a manner as to move the instrument 32 into almost any position within a hemisphere having a central polar axis which is coincident with the Z axis (Fig. 8) .

Instrument In the embodiment of the invention illustrated in Figs. 4 and 5, the instrument 32 includes a rotatable cutter 124 (Fig. 5) . The cutter 124 is connected with a drive shaft 126 (Fig. 3) of a motor in the handle 28 (Fig. 1) . During operation of the motor, the cutter 124 is rotated to cut tissue. Although the cutter 124 may have many different constructions, it is contemplated that the cutter may be constructed in a manner similar to that disclosed in U.S. Patent No. 4,598,710.

Other known surgical instruments may be substituted for the cutter 124. Thus, a generally spherical rotatable burr or router may be used to abrade tissue. Of course, the particular type of instrument 32 which is connected with the outer end portion of the articulated section 34 will depend upon the surgical operation to be performed. The cutter 124 is rotatable about the longitudinal central axis of the stem section 30 to cut tissue. A rigid tubular metal drive shaft 128 extends axially from the drive shaft 126 through the rigid portion 33 of the stem section 30 to the articulated section 34 (Figs. 3, 4 and 5) . Since the articulated section 34 is capable of being deflected in any desired direction, the rigid drive shaft 128 stops short of the articulated section 34 and, in this embodiment, is secured to a flexible tubular polymeric drive shaft 130 (Fig. 7) . The flexible drive shaft 130 extends through the articulated section 34 and is connected to the rotatable cutter 124.

The rigid drive shaft 128 is connected with the drive shaft 126 (Fig. 3) of a suitable electric motor in the handle 28 and is rotated about its longitudinal central axis by operation of the motor. The rigid drive shaft 128 is rotatably supported within a rigid tubular metal housing 134 by a plurality of spaced apart bearing or spacer blocks 136 (Figs. 3, 4 and 7) . The bearing blocks 136 are disposed at spaced apart locations about the circumference of the drive shaft 128. The bearing blocks 136 are fixedly connected with the stationary housing 134 and support the drive shaft 128 for rotation relative to the housing. The wires 102 and 104 (Fig. 7) extend through space between adjacent bearing blocks 136. It should be noted that suitable guides (not shown) are provided on the inside of the housing 134 to guide the wires 102 and 104 between the articulated section 34 and the actuator assembly 38. Although many different types of known guides could be used, it is contemplated that it may be preferred to utilize guides having holes through which the wires 102 and 104 extend and which are formed of suitable polymeric material to minimize friction against the surface of the wires 102 and 104.

The wires 102 and 104 are disposed radially outwardly of the rigid metal drive shaft 128 and the flexible drive shaft 130. This allows the outer end portions of the wires 102 and 104 to be fixedly secured to diametrically opposite portions of the instrument 32 in the manner indicated schematically at 142 and 144 in Fig. 7.

It is contemplated that a thin flexible polymeric sheet may be provided around the articulated section 34. However, the sheet has been omitted in the drawings for purposes of clarity of illustration.

Second Embodiment

In the embodiment of the invention illustrated in Figs. 1-8, the actuator assembly 38 is operable to bend the articulated section either upwardly or downwardly from the Z axis in the plane of the Y axis (Fig. 8) . However, the articulated section 34 is constructed so that it is deflectable or bendable by forces applied to the instrument 32 or the articulated section 34 to deflect the instrument 32 to either side of the plane of the X and Z axes, in the manner indicated schematically in Fig. 8.

It is contemplated that it may be desirable to have the actuator assembly 38 constructed in such a manner as to be operable to bend the articulated section 34 in any desired direction. An embodiment of the invention having an actuator assembly constructed so as to deflect the articulated section 34 in any desired direction is illustrated in Fig. 9. Since the embodiment of the invention illustrated in Fig. 9 is generally similar to the embodiment of the invention illustrated in Figs. 1-8, similar numerals will be utilized to designate similar components, the suffix letter "a" being associated with the numerals of Fig. 9 in order to avoid confusion.

In the embodiment of the invention illustrated in Fig. 9, a surgical instrument 20a has a handle 28a which is connected with an instrument 32a by a stem section 30a. The stem section 30a includes a rigid section 33a and an articulated section 34a.

In accordance with a feature of this embodiment of the invention, an actuator 38a is provided to move the instrument 32a in a plane containing the Z and Y axes (Fig. 8) . A second actuator assembly 152 is provided to move the instrument 32a in the plane containing the X and Z axes (Fig. 8) . Thus, the two actuator assemblies 38a and 152 function as an actuator system which enables a surgeon to move the instrument 32a anywhere within a hemisphere by operating the actuator assemblies.

The actuator assembly 38a is connected with the instrument 32a by wires 102a and 104a. The actuator assembly 152 is connected with the instrument 32a by wires 156 and 158. The wires 102a, 104a, 156 and 158 are connected with the instrument 32a at locations which are offset from each by 90° about the circumference of the instrument 32a. The wires 102a and 104a are connected with the instrument 32a at locations which are diametrically opposite from each other. The wires 156 and 158 are connected with the instrument 32a at locations which are located diametrically opposite from each other and on a diameter which extends perpendicular to a diameter extending through the connections of the wires 102a and 104a to the instrument 32a. The combination of the four wires 102a, 104a, 156 and 158 and the actuator assemblies 38a and 152 enable the instrument 32a to be pivoted in any desired direction relative to the rigid stem 33a.

In the embodiment of the invention illustrated in Fig. 9, the actuator assembly 152 has the same construction as the actuator assembly 38a. However, it is contemplated that it may be desirable to combine the functions of the actuator assemblies 152 and 38a into a single actuator assembly which would operate all four wires 102a, 104a, 156 and 158. However, it should be understood that the two actuator assemblies 38a and 152 cooperate and function together in such a manner so as to enable a surgeon to move the instrument 32a in any desired direction from the initial position shown in Fig. 9.

The present invention relates to a surgical instrument 20 which is particularly well adapted for arthroscopic and/or endoscopic surgery. The surgical instrument 20 has a stem section 30 which is attached to a handle 28. A suitable instrument 32, such as a cutting tool, is connected with an outer end portion of the stem section 30 by an articulated section 34. An actuator 38 is provided to bend the articulated section 34 to change the orientation of the instrument 32 relative to the stem section 30 and body tissue.

In one embodiment of the invention, a pair of flexible elongated elements 102 and 104, such as wires, are provided to bend the articulated section 34 in opposite directions from an initial position. In this embodiment of the invention, the articulated section 34 may be constructed so as to freely flex in a direction transverse to the direction . n which the articulated section is bent by the elongated elements 102 and 104. In another embodiment of the invention (Fig. 9) , a plurality of elongated elements 102a, 104a, 156 and 158, such as wires, are provided to flex or bend the articulated section 34a in any one of four directions. Third Embodiment

Another embodiment is shown in Figure 10-12. The previous embodiment utilizes a tubular polymeric shaft 130. In this embodiment, a spring wire extension 230 is used in place of the shaft 130. The cutter 124, rigid drive shaft 128 and drive shaft 126 are the same as that previously described. The tubular shaft 128 has a distal end 128a and a proximal end 128b. As previously described, the proximal end is a suitable for attachment to a rotatable driver. The shaft 128 defines a bore 128a. In a preferred embodiment, the drive shaft has an outside diameter of 0.127 inches and an inner diameter of 0.093 inches and is 9 1/4 inches long. However, as will be described more fully hereafter, these dimensions may be modified.

The spring wire extension has a proximal end 230a and a distal end 230b. The proximal end 230a is operatively connected to the distal end 128a of shaft 128. Preferably, the spring wire extension 230 is operatively connected to the tubular shaft 128 by a suitable means such as high energy welding. High energy welding may include laser welding or electrical current welding. The advantages of a high energy weld is that there is precise heat and the spring wire extension 230 and shaft 128 are integrated at the butt of the weld. If other types of attachment are utilized, such as grooves being provided in the shaft 128 and the spring wire screwed on, then wall thickness becomes a significant problem. Further, other attachment means such as soldering, do not provide a strong mechanical bond. With the high energy welding, the shaft 128 is not enlarged and there is not a decrease in the internal diameter. The high energy welding provides for an ultra light weight connection which is tough and flexible. Preferably, the spring wire extension has a closed end at the proximal end for easier attachment to the shaft 128. A closed end refers to how the last revolutions of the wire are finished and does not imply that there is an obstruction to the internal path 230c.

The spring wire extension 230 is shown to have a generally circular cross section, however, it is recognized that a rectangular cross section spring may also be utilized as well as other suitable shapes. The rotatable cutter 124 is operatively connected to the distal end 230b of the spring 230 by suitable means such as laser welding. Suitable material for the spring 230 includes stainless steel, Elgiloy™, tungsten rhenium and nickel titanium, such as Tinel™ or Nitinol™ by Raychem. The pitch of the spring 230 is approximately 1:2. By varying the pitch, diameter, material, and shape of the spring 230, a spring can be created which is suitable for a variety of drive shafts. The wider the pitch, the stiffer the spring and, therefore, more torsional strength. The spring 230 is flexible through an angle greater than 90° to the axis of the tubular shaft. Preferably, it is flexible through an angle of greater than 135° and still more preferable to an angle greater than 175° to an axis of the tubular shaft 128. While being flexible, the spring wire extension 230 maintains an internal path 230c for withdrawal of human tissue. The internal path 230 is sized substantially equal to the bore 128a of the tubular shaft 128. As previously discussed, the spring wire extension 230 permits a tool 124 to be carried by its distal end 230b, whereby rotary motion applied to the drive shaft by a rotatable driver can be transmitted to a tool 124 carried by the spring wire extension 230.

The drive shaft is operated within an articulated guide tube and is previously disclosed. However, it is understood that a drive shaft may be also operated inside of a precurved tube. While this would eliminate the ability to further move the drive shaft as shown in Figure 8, such a precurved tube would still be useful to take of the ability of the drive shaft to be bent through such a large angle. The tool can still be utilized to evacuate more human tissue thru greater degrees of fixed curvature than that available by prior art devices . When prior art flexible shafts and precurved tubes were used for evacuating material, the shafts tended to snap if the fixed curve radius was greater than 20°. The spring wire extension of the present invention does not snap and is able to be flexible thru a much greater angle, as previously discussed.

A heat shrink covering 240 is preferably applied around the outside of the spring 230. The heat shrink covering 240 may be made of a suitable material such as PFE or polyurethane. The covering 240 helps prevent unwinding and also provides for more efficient sucking action through the internal path 230. The thickness of the covering 240 is 0.002 inches.

In the embodiment shown, the spring 230 has an outside diameter of 0.125 inches and an inner diameter of 0.093 inches. The wire has a diameter of 0.016 inches although larger sized diameters may be used, e.g. up to 0.050 inches. The internal diameter of the spring 230 is substantially equal to the internal diameter of the drive shaft 128. For use during surgical procedures where there is aggressive evacuation of human tissue, an internal diameter for both the drive shaft and spring of greater than 0.050 inches (a cross-sectional area of 0.002 square inches) is preferred and it is understood that the internal diameter could go up significantly from there to at least 0.240 inches. Preferably, the internal diameter is greater than 0.080 inches (a cross- sectional area of 0.005 square inches) and 0.090 to 0.110 inches (a cross-sectional area of 0.006 - 0.009 square inches) are preferred. Further, it is understood that smaller openings in the range of 0.030 inches may be applicable for non-aggressive removal of human tissue.

In use, the steerable and flexible drive shaft is utilized in a method of manipulating a tool within a non-lumen portion of a body. Steerable is used to indicate that the drive shaft is "steerable" by being placed in a precurved tube or in an articulated section such as that described in this application. An entry opening into the particular portion of the body to be operated on is prepared by suitable means. For disc surgery, this would include cutting the body. For sinus surgery, no additional entry opening is needed other than that already existing in the nose to the sinus cavities. The surgical instrument is then inserted into the prepared opening. The tool 124 is then rotated and human material is dislodged and evacuated through the internal path and bore. Irrigation is provided around the outside of the tool within an outer canula to the site of the tissue to be removed. Suction then is used to evacuate thru the internal path and bore, this being well known in the art. Further human tissue may be evacuated by movement of the surgical instrument further into the prepared opening. The surgical instrument may also be rotated to allow for still more evacuation of human tissue. Then, the articulating section of the instrument may be moved from a first position to a second position, as shown in Figure 8, thereby evacuating additional human material.

Also, while the spring 230 is shown as a single spring, it is understood that multiple springs could be used such as a two-component spring wherein there is a right hand spring which is overlaid by a left hand spring thereby forming a spring wire extension. Also, while the control apparatus 22 is shown as an electrically operated control panel thereby providing rotary motion electrically, it is also understood that rotary motion may also be applied by suitable hand- driven means, well known in the art.

Other modifications of the invention will be apparent to those skilled in the art in light of the foregoing description. This description is intended to provide specific examples of individual embodiments which clearly disclose the present invention. Accordingly, the invention is not limited to these embodiments or the use of elements having specific configurations and shapes as presented herein. All alternative modifications and variations of the present invention which follow in the spirit and broad scope of the appended claims are included.

Claims

We Claim :

1. A flexible drive shaft for a medical tool to be manipulated within the human body, said drive shaft being characterized by: (a) a thin-walled, hollow, tubular shaft having a distal end, a proximal end, the proximal end being suitable for attachment to a rotatable driver, the hollow tubular shaft defining a bore;

(b) a spring wire extension having a proximal end and a distal end, the proximal end operatively connected to the distal end of the tubular shaft, said spring being flexible through an angle greater than 90° to the axis of the tubular shaft while maintaining an internal path for the withdrawal of tissue, said path is sized substantially equal to the bore of the tubular shaft; and

(c) said spring wire extension permitting a cutting tool to be carried by the distal end of said spring wire extension, whereby rotary motion applied to the drive shaft by a rotatable driver is transmitted to a tool .

2. The drive shaft of claim 1, wherein the drive shaft is bent in a desired direction by deflection of the spring extension and the drive shaft is operated within a articulated guide tube. -

3. The drive shaft of claim 1 in which the rotatable driver is an electrically operated driver.

4. The drive shaft of claim 2 in which the rotatable driver is an electrically operated driver.

5. The draft shaft of claim 1, wherein the spring wire extension is operatively connected to the tubular shaft by high energy welding.

6. The drive shaft of claim 1/ wherein the spring wire extension has a closed end proximate the tubular shaft.

7. The drive shaft of claim 1, further comprising a heat shrink covering over said spring wire extension thereby allowing for a more efficient suction action.

8. The drive shaft of claim 1, wherein the spring is flexible through an angle greater than 135°.

9. The drive shaft of claim 1, wherein the spring is flexible through an angle greater than 175°.

10. A flexible drive shaft for a medical tool to be manipulated within the human body, said drive shaft being characterized by:

(a) a thin-walled, hollow, tubular shaft having a distal end, a proximal end, the proximal end being suitable for attachment to a rotatable driver, the hollow tubular shaft defining a bore;

(b) a spring wire extension having a proximal end and a distal end, the proximal end has a closed end and is high energy welded to the distal end of the tubular shaft, said spring being flexible through an angle greater than 90° to the axis of the tubular shaft while maintaining an internal path for the withdrawal of human tissue, said path sized substantially equal to the bore of the tubular shaft; (c) said spring wire extension permitting a tool to be carried by the distal end of said spring wire extension, whereby rotary motion applied to the drive shaft by a rotatable driver can be transmitted to a tool carried by the spring wire extension; and (d) a heat shrink covering over said spring wire extension thereby allowing for a more efficient suction action.

11. The drive shaft of claim 10 wherein the drive shaft is bent in a desired direction by deflection of the spring extension and the drive shaft is operated within a articulated guide tube.

12. The drive shaft of claim 10, wherein the internal path of the spring wire extension has an internal diameter of at least 0.050 inches.

13. The drive shaft of claim 10, wherein the internal path of the spring extension has an area of at least 0.002 square inches.

14. A surgical instrument comprising: (a) a stem section extending from a handle;

(b) a tool;

(c) a hollow section connected with the tool and the stem section;

(d) a rotatable drive shaft connected with the tool and disposed in and extending axially thru the stem section and said hollow section;

(e) the drive shaft to rotate the tool, the drive shaft having a flexible portion disposed in the hollow section and the drive shaft is rotatable relative to the hollow section; and

(f) the drive shaft characterized by:

(i) a thin-walled, hollow, tubular shaft having a distal end, a proximal end, the proximal end being suitable for attachment to a rotatable driver, the hollow tubular shaft defining a bore;

(ii) a spring wire extension having a proximal end and a distal end, the proximal end operatively connected to the distal end of the tubular shaft, said spring being flexible through an angle greater than 90° to the axis of the tubular shaft while maintaining an internal path for the withdrawal of tissue, said path sized substantially equal to the bore of the tubular shaft; and

(iii) said spring wire extension permitting a tool to be carried by the distal end of said spring wire extension, whereby rotary motion applied to the drive shaft by a rotatable driver can be transmitted to a tool on the spring wire extension.

15. The surgical instrument of claim 14, wherein said hollow section is articulating and further comprising means for changing the articulating section and thereby the tool from a first orientation to a second orientation.

16. The surgical instrument of claim 14, wherein the spring wire extension is laser welded to the tubular shaft.

17. The surgical instrument of claim 14, wherein the spring wire extension has a closed end proximate the tubular shaft.

18. The surgical instrument of claim 14, further comprising a heat shrink covering over said spring wire extension, thereby allowing a more efficient suction action.

19. A method of manipulating a tool within a non- lumen portion of a body, the method comprising: (a) preparing a suitable entry opening into a body;

(b) inserting a surgical instrument into the prepared opening, the surgical instrument having a tool operatively connected to a rotary drive by a flexible drive shaft, the drive shaft being characterized by:

(iii) said spring wire extension permitting a tool to be carried by the distal end of said spring wire extension, whereby rotary motion applied to the drive shaft by a rotatable driver can be transmitted to a tool carried by the spring wire extension;

(c) rotating the tool and evacuating human material dislodged by the tool through the internal path and hollow tubular shaft .

20. The method of claim 19, wherein the instrument comprises an articulating section in which the spring wire section is positioned and means for changing the articulating section and thereby the tool from a first orientation to a second orientation, the method further comprising, moving the articulating section from a first position to a second position and thereby evacuating additional material.