Surgical cutting instrument

Abstract: A surgical cutting instrument is disclosed in FIG.4 for percutaneously debulking tissue through an access sheath. The cutting instrument includes an inner rotary member tube 401 having a cutting edge 407 at the distal end thereof for cutting and slicing tissue. The outside surface of the rotary inner cutting member tube and outer sheath 409 annularly close about the distal ends thereof for preventing perforation of the surgical tissue bag in which the tissue is contained. The inner cutting member tube includes a hollow passageway for suctioning and aspirating tissue and fluid through the tube and into a collection chamber 419 or out through a vacuum or suction line 422 attached thereto. Vacuum or suction control ports are included at the proximal end of the inner cutting member tube and stationary sheath for also controlling the amount of vacuum or suction applied to the tissue. The surgical cutting instrument includes a control handle 431 for grasping by the physician. A collection chamber is connected to a coupler connected to the stationary sheath for collecting tissue therein. The inner cutting member tube extends through the collection chamber to a drive motor 440 or to a remotely positioned rotary drive mechanism. A vacuum line is attached to the collection chamber for drawing tissue and fluid through the inner cutting member tube and into the collection chamber.

Description: This invention relates to percutaneous surgical cutting instruments and preferably to surgical instruments for debulking biological tissue. U.S. Patent Application No. 543,679 in the prior art statement thereof, describes surgical debulking instruments disclosed before June 22nd 1990. A problem associated with side port or partially open-ended instruments, are the complex angles that are required for the cutting edges. Not only do these complex cutting angle instruments have limited access, but also provide limited control or directionality with respect to slicing or cutting soft tissue. U.S. 4,517,977 discloses a surgical cutting instrument with a fixed outer sheath and a fixed blade at the distal end thereof. There is an inner member rotatably mounted within the sheath and with a blade at the distal end for cooperating with the other blade in a scissors type action as disclosed in the preamble of claim 1. U.S. 4,772,258 discloses a surgical cutting instrument in which an inner member is rotatably mounted within an outer tube, with the inner member extending beyond the distal end of the outer tube when in the operative condition. According to the present invention there is provided an instrument as defined in claim 1. The problem of inadvertently cutting tissue with an open-ended surgical instrument is solved and a technical advantage is achieved by a surgical cutting instrument of an embodiment of the invention in which a cutting edge, that is positioned circumferentially about the distal end of an inner rotating member, is contained within the passageway of a stationary outer sheath. To further safeguard the cutting edge from inadvertent contact, the outer surface of the inner member and outer sheath annularly close about the distal ends thereof. The contours of the annular closings of the sheath and the member conform to one another, but they can be different if required. The cutting action of the instrument is facilitated with a sideways motion when tissue is drawn through the distal ends of the outer sheath and inner member. The distal ends of the elongated sheath and the inner member each have a distal opening therein. The hollow passageway of the elongated sheath has a first predetermined cross-sectional dimension, whereas the distal opening of the sheath has a predetermined cross-sectional dimension smaller than that of the sheath passageway. The distal opening of the inner member is positioned within the elongated sheath and has a cross-sectional dimension preferably smaller than the cross-sectional dimension of the inner member passageway. Positioned between the inner member and elongated sheath is a bearing surface on which the inner member rotates freely within the passageway of the outer sheath. The bearing surface comprises an electrolysed material such as chrome deposited on the outer surface of the inner member about the distal and proximal ends thereof. In another embodiment, the bearing surface comprises a tube of PTFE that extends between the distal and proximal ends of the inner member. The cutting instrument includes suction means for drawing tissue through the first and second distal openings of the outer sheath and inner member The annularly closing outer surface of the elongated sheath and inner member positioned about the distal ends thereof includes a uniformly radiused curvature for facilitating easy rotation of the inner member within the outer sheath and also for advantageously preventing inadvertent head-on cutting of tissue. Brief description of the Drawings FIGS.1, 2 and 3 illustrate figures which have been fully described and claimed in U.S. Patent Application No.07/543,679 filed on June 22nd 1990. For a description of these figures reference is made to FIGS.1 to 3 and the description thereof in the above application. FIG.4 depicts a partially sectioned side view of an embodiment of the present invention; FIG.5 depicts a partially sectioned side view of the distal end of the surgical cutting instrument of FIG.4; and FIG.6 depicts a partially sectioned pictorial view of the distal end of the surgical cutting instrument of FIG.4. Depicted in FIG.4 is a partially sectioned side view of an illustrative surgical cutting instrument 400 having a rotary, open-ended cutting edge 407 for percutaneously debulking and cutting tissue. The cutting edge is completely contained within passageway 412 of outer sheath 409, which is curved at distal end 410 thereof to prevent perforation of a surgical tissue bag. The cutting instrument comprises an inner elongated cutting member tube 401 rotatably positioned within outer elongated sheath tube 409. Tissue is drawn into hollow passageway 404 of inner cutting tube member 401 with a vacuum applied thereto and cut with a sideways or lateral motion of the distal end of the instrument, which is provided by the attending physician. Rotary drive mechanism 416 includes, for example, electric motor 440, which is positioned about proximal end 403 of inner cutting member tube 401 for rotating the tube and cutting tissue drawn within. A suction or vacuum line 422 is connected to the handle of the instrument to draw tissue within hollow passageway 404 of the inner cutting member tube. Severed tissue is drawn through the inner cutting member tube and exits evacuation port 418 of the tube into tissue collection chamber 419, which is positioned in the handle 431 of the instrument. Conically shaped screen 423 positioned in the bottom of the tissue collection chamber over vacuum port 424 prevents the severed tissue from exiting the chamber and blocking the vacuum line. Vacuum control means 417 includes stopcock 425 that is positioned between the vacuum port and vacuum line and controls the amount of suction or vacuum applied to the cutting instrument. The rotary drive mechanism of the embodiment of FIGS.4,5 and 6, can alternatively be replaced by another form of drive mechanism such as shown in the arrangements of FIGS.1, 2 or 3. Similarly the handle and evacuation system of the embodiments of FIGS.4, 5 and 6 can be replaced by other forms of handle and evacuation system such as shown in the arrangements of FIGS.1, 2 or 3. Inner cutting member tube 401 includes distal end 402, proximal end 403, and hollow passageway 404 extending longitudinally therein. Surrounding the rotary inner cutting member tube is stationary outer elongated sheath tube 409 with proximal end 411 thereof connected to the handle of the instrument via coupler 426. Hollow passageway 412 extends longitudinally in the outer sheath between distal end 410 and proximal end 411. Depicted in FIGS.5 and 6 are enlarged partially sectioned views of distal end 402 of inner cutting member tube 401 and distal end 410 of outer sheath 409 of the cutting instrument. To prevent perforation of a surgical tissue bag of which the tissue is contained, the distal end 410 including the outer surface 413 of the stationary outer sheath closes annularly thereabout, to provide distal opening 414. The distal end 410 extends beyond the distal end 402 of cutting member 401, and is partially closed about the end 402 except for the opening 414. The annular closing of end 410 is shown in FIGS.5 and 6 as being partially dome shaped. It will be appreciated, however, that the end 410 can be partially annularly closed about the end 402 by annular closures of other shape, such as a frusto-conically shaped end. It is preferable that the distal end 402 of cutting member 401 is partially annularly closed in a manner similar to that of end 410. The end 402 can, however, be of a different shape to that of end 410 if required, but it should be within the passageway of the sheath at the distal end 410, in the sense that end 406 is inwardly spaced from end 414. Tissue is drawn through distal opening 414 of the outer sheath for engagement with rotary cutting edge 407 that is circumferentially positioned about distal opening 406 of the rotary inner cutting member tube. The physician applies a sideways or circular motion to the distal end of the instrument for rotary edge 407 to cut the tissue drawn through the distal openings of the outer sheath and inner member tube. To further prevent perforation of the surgical tissue bag and ease operation of the instrument therein, respective annularly closing surfaces 427 and 428 of outer sheath 409 and inner cutting member tube 401 are uniformly radiused. As a result, distal opening 414 of the outer sheath and distal opening 406 of the inner cutting member tube each have a cross-sectional diameter dimension smaller that the cross-sectional diameter dimension of respective hollow passageways 412 and 404. In addition, circular distal opening 406 of the inner tube is positioned within distal opening 414 of the outer sheath and has a smaller cross-sectional diameter dimension to draw tissue into the inner cutting member tube and into contact with rotary cutting edge 407 to cut the tissue with a sideways or circular motion provided by the attending physician. It is preferable that the rotary cutting edge 407 has a diameter which is less than the diameter of opening 414 to facilitate cutting of the tissue. If required, however, the diameter of edge 407 can be equal to or less than the diameter of opening 414. By way of example, outer elongated sheath tube 409 comprises a 300 series stainless steel tube approximately 12.38cms (4.875") in length with an outside diameter of 1.09cms (0.428") and inside diameter of 1.04cms (0.41"). The diameter of distal opening 414 of the outer sheath is approximately 0.79cms (0.31") to 0.8cm (0.315") with outer annularly closing surface 427 having a uniform radius of approximately 0.254cms (0.1"). Inner cutting member tube 401 comprises a 19cms (7.5") length of 300 series stainless steel tube having an outside diameter dimension of approximately 0.96cm (0.377") with a wall thickness of 0.0254cm (0.01") resulting in an inside diameter of approximately 0.9cm (0.357"). The diameter of circular distal opening 406 is approximately 0.698cm (0.275") with outer annularly closing surface 428 having a uniform radius of approximately 0.254cm (0.1"). Rotary cutting edge 407 has an included angle of approximately 25 to 30 degrees and faces inwardly in a perpendicular radial direction toward the longitudinal axis of the cutting tube. This particular orientation provides for a sideways cutting or sculpting action when tissue is drawn with suction through distal opening 406 and 414. As partially depicted in FIG.4, approximately 0.95cm (0.375") from proximal end 403 of the inner cutting member tube, evacuation port 418 extends for approximately 2.86cms (1.125") with a depth of 0.45cm (0.177") from outer surface 405 into hollow passageway 404. Nylon coupler 408 is fixedly positioned in hollow passageway 404 and extends from proximal end 403 of the inner cutting member tube for detachable engagement with shaft 441 of electric motor 440. As depicted in FIGS.4 and 5, positioned about distal end 402 on outer surface 405 of the inner member is distal bearing surface 415 approximately 0.5cm in length and 0.5cm from distal end 402. This bearing surface is approximately 0.038cm (0.015") in thickness and comprises an electrolysed material such as 95% hard chrome for rotating inner member 401 within the passageway of the outer sheath. A proximal bearing surface 420 is similarly positioned on the outer surface of the inner member about the proximal end of the outer sheath. The distance between the distal ends of the rotary inner cutting member tube and the stationary outer sheath is maintained with thrust disc 429, which is positioned around inner member tube 401 proximal to the outer sheath and engages distal handle coupler 426 and PTFE bearing disc 430. Alternatively as shown in FIG.6, a thin-wall tube 421 of approximately 0.038cm (0.015") PTFE material is inserted between the inner member and outer sheath, which acts as the bearing surface. Hollow passageway 404 of rotary inner cutting member tube 401 extends the entire length of the tube for drawing and removing tissue severed from the surgical site through tissue evacuation port 418 and into tissue collection chamber 419. Handle 431 of the instrument comprises a cylindrical T-shaped member with coupler 426 fixedly positioned in distal cross-bar opening 432. Rotary inner cutting member tube 401 is inserted through proximal cross-bar opening 433 of handle 431 and into outer sheath 409. A circular solimide material disc 434 is positioned about the proximal end of the cutting tube to prevent tissue from being drawn into electric motor 440. The disc is fixedly positioned in passageway 435 of the handle about proximal cross-bar opening 433 between inwardly extending flange 436 and the distal end of the rotary drive mechanism. Tissue collection chamber 419 of the cutting instrument handle includes hollow T-shaped passageway 435 which communicates with inner passageway 404 of the rotary inner cutting member tube via evacuation port 418. The tissue collection chamber is enclosed by cylindrical wall 437 of the T-shaped handle. The proximal end of the chamber includes removable cap 438 with chamber evacuation port 424 positioned therein and vacuum stopclock 425 extending therefrom. As previously discussed, conically-shaped screen 423 prevents tissue from being drawn through evacuation port 424 and into vacuum or suction line 422. Suction means 417 of the cutting instrument comprises evacuation port 424, stopcock 425, and conically-shaped screen 423. The cylindrical T-shaped handle of the instrument is comprised of any well-known plastic material such as PVC which is easily moulded and shaped. Rotary drive mechanism 416 comprises a commercially available electrical motor 440 that is encased, for example, in plastic material cylinder case 439, which is readily screwed into proximal cross-bar opening 433 of the handle to engage rotary inner cutting member tube coupler 408. With rotary drive mechanism 416 rotating inner cutting member tube 401, tissue is severed with cutting edge 407 and drawn through hollow passageway 404 and into tissue collection chamber 419 via evacuation port 418. A power and control line (not shown) is connected to the rotary drive mechanism to energize and control the speed of the electric motor. The physician controls the speed, for example, with the use of a foot pedal (not shown) connected to the power and control line. The vacuum applied to the tissue collection chamber via the suction means draws the severed tissue from the inner cutting member tube and into the collection chamber of the surgical cutting instrument handle. The physician regulates the suction applied to the chamber via stopcock 425. The distal end of the cutting instrument may be devised to include serrated teeth or a modified cutting edge for providing any number of different cutting or slicing actions. The rounded distal end of the outer shield may be devised to include a series of rounded wires to permit penetration through soft tissue to permit cutting and slicing by the inner cutting member tube. Such a wire cage arrangement would also prevent puncture of a surgical tissue bag should one be desired to be used by the physician.

Claims: A surgical cutting instrument comprising an elongated fixed outer sheath (409) with a passageway (412) therethrough, an elongated tubular cutter member (401) rotatably mounted within the passageway of the sheath, a mechanisme (416) for rotatably driving the said member within the sheath (409), the distal end (402) of the member providing a peripheral circumferential cutter blade (407) for cutting through tissue, and means for removing cut-through tissue via the said member, characterized in that the distal end of the sheath is partially annularly closed to provide a distal end opening (414) of smaller cross sectional dimension than said passageway, and in that the cutter blade of the said member is during cutting, contained within the said passageway, with the cutter blade spaced inwardly from the said distal end opening. An instrument according to claim 1, wherein the cutter blade is serrated or continuous. An instrument according to claim 1 or 2, wherein the inward curving of the outer sheath is in a smooth continuous manner of uniformly radiused curvature, and wherein the distal end of the tubular member is inwardly curved in a continuous manner also of uniformly radiused curvature. An instrument according to claim 3, wherein the distal blade (406) of the tubular cutter is of smaller dimension than the dimension of said distal end opening (414). An instrument according to any one preceding claim, wherein bearing surface means (415,420) are provided between the outer sheath and the said member to facilitate rotation of said member. An instrument according to claim 5, wherein the bearing means are in the form of electrolyzed surfaces formed on the said member. An instrument according to any one preceding claim, wherein the said member has an evacuation port (418) at a position along the member remote from the said distal end thereof, and wherein the port is in communication with the said means for removing, the latter comprising a suction arrangement. An instrument according to claim 7, further comprising a tissue collection chamber (419) connected between the evacuation port and the suction arrangement, the chamber being contained within the handle (431) of the instrument. An instrument according to claim 7, further comprising a shaped screen (423) within the collection chamber to prevent tissue within the said chamber from reaching the suction arrangement.

Inventors: PINGLETON EDWARD D, THOMSON PAUL G, PINGLETON, EDWARD D., THOMSON, PAUL G.
Applicants: VANCE PRODUCTS INC, VANCE PRODUCTS INCORPORATED D/B/A COOK UROLOGICAL INCORPORATED AND COOK OB/GYN
Application year: 1992
Main classification: A61B17
IPC codes: A61B17