Apparatus for Providing Enhanced Tissue Fragmentation and/or Hemostasis

The invention will be more particularly described with reference to a preferred embodiment as illustrated in the accompanying drawings, in which:

FIG. 1 is a side elevation, partly in section, of a surgical apparatus including the improved switching means of the invention;

FIG. 2 is an enlarged view of the section A defined by dotted lines in FIG. 1;

FIG. 3 is a side elevation of a conductive O-ring used in the switching means of the invention; and

FIG. 4 is a section through the O-ring of FIG. 3.

The apparatus illustrated in FIG. 1 of the drawings comprises a handpiece shown generally at 1 which is capable of performing ultrasonic fragmentation, aspiration, electrosurgical cutting, fluid irrigation, and electrosurgical coagulation or hemolysis functions on tissue at a surgical site on a patient. These functions may be performed either separately or simultaneously in any combination. The basic handpiece is preferably a known ultrasonic fragmentation handpiece such as that described in U.S. Pat. No. 4,063,557 or the above-mentioned CUSA handpiece, modified to include electrosurgical cutting and coagulating functions. These modifications can be built into the handpiece itself, or provided as part of a disposable or replaceable handpiece component such as on the manifold or nosecone thereof.

Handpiece 1 as shown in FIG. 1 comprises a plastic housing 2 and nose cone 3 sized and configured to be easily and comfortably gripped and manipulated by the surgeon's hand. The housing 2 accommodates an ultrasonic transducer 4 and the proximal end of an electrically conducting metal acoustic connecting member 5; and the housing 2 is threadably engaged to the nose cone 3 which accommodates the distal end of the connecting member 5 and the proximal end of an elongated tapered ultrasonically-vibratable tool 6. The tool, which also is made from an electrically-conducting metal, for example titanium, is threadably connected to the connecting member through a male thread 7. The tool 6 is disposed in a forward direction so that the tool tip 8 extends forwardly a distance out from the housing and has a tip opening 9 at its distal end. The tool is hollow and defines a longitudinal tool passageway therethrough.

An aspiration pump (not shown) can apply a suction pressure through tube 10 so that when the latter is connected to the proximal end 23 of the tool through conduit 11 tissue particles, blood, fluids and the like at a surgical site can be aspirated from the surgical site through the tool tip opening 9 and the tool passageway to be disposed in a suitable suction container (not shown).

One of the fluids which may be aspirated from the surgical site is a saline irrigation fluid provided thereto as part of the surgical procedure as for example to provide a suspension fluid for the tissue particles fragmented by the tool 6. The saline irrigation solution may drain by gravity in a known manner from a bottle or bag suspended above the surgical site through an irrigation tubing (not shown) to and into an appropriate inlet port in the handpiece. It then flows through an annular passage defined between the tool 6 and a plastic sleeve or manifold 12 surrounding the tool, and then out from the manifold around the tool tip 8 to the surgical site. In addition to supplying irrigation fluid to the surgical site, the fluid cools the vibrating tip 8 and adjacent healthy tissue is protected from damage. By mixing the fluid with the blood, tissue particles and other aspirated material coagulation of the blood is slowed down and aspiration thereof is aided. Where the surgical site is an enclosed or semienclosed area such as the eye in ultrasonic cataract removal procedures, it is important to maintain a pressure therein within a certain range, and flow control systems for maintaining such pressures are known, and can be used herein. See, for example, U.S. Pat. No. 3,693,613. Control of the delivery of irrigating fluid, and application of aspiration suction pressure and-ultrasonic energy can be by a footswitch readily accessible to the surgeon as is known in the art.

The tool 6 is ultrasonically vibrated and is part of a resonant vibrating system mounted in the handpiece and comprising the connecting member 5 and transducer 4. The preferred transducer comprises a magnetostrictive stack as disclosed in U.S. Pat. No. Re. 25,033. The tool 6 preferably comprises a substantially unitary body having a male thread at its proximal end and is designed for replacement as required and attachment to the distal end of the connecting member 5. Preferably the ultrasonic resonator causes the tip 8 to vibrate ultrasonically with a stroke in excess of 0.001 inch and preferably 0.014 inch and at a frequency range of 20 KHz-50 KHz and preferably 23 KHz-37 KHz.

The electrosurgical unit (ESU) which provides the RF energy for the improved surgical apparatus of the invention may be a free standing hospital unit such as that disclosed in U.S. Pat. Nos. 3,898,991; 3,963,030 or 4,051,855 or, alternatively, it may be included in a single, preferably portable, unit within the same housing as the aspirator pump. The ESU generates RF energy and is operatively connected through a cable (not shown) to a switching means 13 on the nose cone 3 of the handpiece 1. Preferably, the ESU comprises a known type of electrical filtering device for preventing malfunction of the logic controls in the ESU when the ESU is activated while coupled, through the switching means, to the tool tip.

The switching means is positioned on the handpiece nose cone so as to be conveniently actuated by the surgeon as he manipulates the handpiece and it allows him to control the delivery of RF energy from the ESU to the tool 6. Thus, the switching means permits the surgeon to select from "no" RF energy, RF coagulating energy, RF cutting energy, and a blend of coagulating and cutting energies. RF cutting and coagulating currents differ and are defined as pure sine wave and damped sine wave, respectively.

The improved switching means of the present invention comprises a handswitch mounted on the nose cone of the handpiece so that it is accessible to and actuated by the surgeon's hand (for example, forefinger) as it holds and manipulates the handpiece.

A preferred embodiment of the handswitch is illustrated in FIG. 1 and comprises a separable and replaceable unit such as an add-on switch assembly attached to a separable handpiece manifold. Alternatively, the hand-switch may be integrally formed with or built into the housing of the handpiece so as to be totally re-usable (not shown). In all embodiments the switch module delivers RF energy to the connecting member of the apparatus through a conductive O-ring as herein described.

The switch assembly may be a push button, rocker or slide construction. A preferred embodiment is a rocker assembly as illustrated schematically in FIG. 1.

The rocker assembly permits the surgeon to select the "cut" mode of RF current from the ESU through normally open dome switches 14 or 15, respectively. When the relevant dome switch is closed the appropriate RF current is caused by a circuit board 16 (FIG. 2) in the switch module, to flow through a bifurcated, electrically conductive terminal 17, an electrically-conductive metal band 18 and an electrically-conductive O-ring 19 into the connecting member 5 and thence to the tool 6.

The electrically conductive O-ring 19 is preferably made from a rubbery elastomer impregnated or loaded with particles of an electrically-conductive material, such as silver-coated aluminum. For a standard ultrasonic surgical tool of the type described hereinabove the conductive O-ring 19 will normally have an internal diameter d (FIG. 3) of about 0.50 to 0.60 inch, preferably 0.56 inch and a cross-sectional diameter c (FIG. 4) of about 0.04 inch. When the nose cone 3 is tightened into locking engagement with the housing 2 the substantially circular cross section of the O-ring 19 is somewhat distorted as shown in figure 2. The resilience of the O-ring coupled with the tight fit allow the O-ring to maintain contact with the connecting member during operation thus avoiding any possibility of arcing. Likewise the contact between the metal band 18 and the O-ring 19 is maintained without arcing so that electrical continuity is sustained during operation of the apparatus. The metal band 18 is made from a ductile strip of electrically conductive metal, for example a beryllium copper alloy, having a thickness of about 0.004 to 0.005 inch. The width of the band is about 0.043 to 0.045 inch. The lower portion of the band is of substantially L-shape with the base of the L in touching contact with the O-ring 19. The upper portion of the band is bent over upon itself to form a springy plug which snaps into the bifurcated terminal 17 and maintains direct touching contact with the inside walls of the terminal at all times.

The connecting member is maintained in fluid-tight contact against housing 2 by a standard O-ring 20; and it is maintained in fluid-tight contact against nose cone 3 by a rearward O-ring 21 and a forward O-ring 22. The said O-rings are made of natural or synthetic rubber or a synthetic elastomeric polymer and are standard components in the art.

The forward O-ring 22 prevents irrigation fluid from entering the space surrounding the middle portion of the connecting member and the O-ring 20 prevents cooling liquid from entering the said space. The middle portion of the connecting member is defined herein as that portion which includes the electrical contact with the electrically conductive O-ring 19. Thus the said space is maintained as a substantially dry space and, consequently, there is no danger of liquid entering the switch module.

Repeated operations with an apparatus incorporating the improved switching means of the invention have resulted in substantially no deterioration in electrical efficiency. Examination of the conductive O-ring itself after numerous prolonged tests have shown no signs of burning or scorching due to arcing and substantially no mechanical deterioration.