IMPROVED SURGICAL INSTRUMENT

Abstract: A microsurgical instrument comprises a generally cylindrical handpiece (10) split longitudinally to provide two semi-cylindrical parts (12, 13) which are pivotally mounted at one end thereof, to a central support member (14), for symmetrical pivotal movement at the other end towards and away from each other. A spring (26) biases the parts (12, 13) away from each other. A spindle (11) extends beyond the second end, comprising a pair of co-axial shafts (16, 17) which are connected at the first end via respective levers (23, 24) to respective handpiece parts (12, 13) and at the second end to a functional tip of scissor, forceps, or the like, type construction each jaw member being connected to only one of the co-axial shafts (16, 17). Squeezing of the handpiece parts (12, 13) together causes simultaneous and symmetrical rotation of the co-axial shafts (16, 17) in opposite directions whereby the jaws of the functional tip are similarly activated symmetrically and in unison.

Description: TITLE: IMPROVED SURGICAL INSTRUMENT The present invention relates to a surgical instrument and mor particularly to an improved surgical instrument of the kind requirin actuation of a handpiece to cause movement of functional parts of th instrument which are mounted on a spindle and are thus remote fro the handpiece. The invention is particularly concerned with suc instruments as forceps, scissors and clamps of the kind used i performing micro surgical operations, for example, on the eye but o course any other type of surgical instrument having moving parts a the remote end thereof could incorporate the invention. Surgical instruments in which actuation is achieved by squeezin parts of the instrument between the fingers of the surgeon have bee developed and while they improve the ability of the surgeon t manipulate the rotational position of the end of the instrument whil actuating the instrument, the drive mechanisms and pivota arrangements of the actuating elements of the instruments have thu far not been altogether satisfactory. For example, instruments wherein the spindle comprises co-axia shafts are known. In these the shafts are caused to slide axiall relative to each other and a split-collett arrangement at the ti causes movement of the jaws. Whilst such an arrangement has th advantage that the jaws move symmetrically there is a problem in tha intra ocular fluids enter the tip and cause binding of the mechanis due to corrosion if not cleaned away immediately after surgery. I addition protein could coagulate inside the mechanism and woul eventually damage the working thereof if not cleaned away completely The cleaning operation is complex and time-consuming if done properl and if not done properly the useful life of the instrument i severely curtailed. One of the present applicant's earlier attempts to provide improved surgical instrument of the kind in question involv co-axial shafts having relative rotary movement to cause operation the jaws and whilst the rotary shafts overcame the problem cleaning because there is no access for fluids into the spindle, on one of the jaws moves in this arrangement and this fact causes oth problems for the surgeon. With only one jaw moving it is often t case that the surgeon, in the performance of a delicate operatio forgets which is the moving and which is the fixed jaw with th undesirable consequence that the material being cut or held may b moved transversely during an operation. Consequently this earlie attempt was deemed unsatisfactory and was abandoned withou publicatio . It is an object of the present invention to provide an improve surgical instrument which avoids or overcomes one or more of th disadvantages of existing surgical instruments of the kind i question. Accordingly the invention provides a surgical instrumen including a handpiece comprising two parts connected for relativ movement towards and away from each other, a spindle extending fro said handpiece to a functional tip comprising jaw members at an en of the spindle remote from said handpiece, said spindle comprisin coaxial shafts each connected to a respective handpiece part and respective jaw member whereby said relative movement of the handpiec parts causes, via said shafts, relative movement of said jaw member towards or away from each other, characterized in that, sai handpiece is of generally cylindrical configuration spli longitudinally to provide said two parts which are connected, toward one end thereof, for symmetrical pivotal movement towards each othe under pressure from the user and away from each other under interna bias whereby said symmetrical movement of the handpiece parts cause symmetrical movement of said jaw members by causing rotation of sai shafts in opposite directions. In order that the invention may be more readily understood on particular embodiment will now be described in detail with referenc to the accompanying drawings wherein: Figure 1 is a side elevation of a surgical instrument according to the invention with jaw members excluded; Figure 2 is an underside view of an axial support member of th instrument of Figure 1; Figure 3 is a side view of the support member of Figure 2; Figure 4 is an end view of the support member of Figure 2; Figure 5 is a view from inside of one of two semi- cylindrica side members of the instrument according to Figure 1; Figures 6 - 9 are sections on the lines A-A to D-D respectivel of Figure 5; Figure 10 is a plan view of a spring member of the instrument; Figure 11 is an end view of the spring of Figure 10, and Figures 12 and 13 show elevations and end views of respectiv lever members of the instrument. The surgical instrument is shown to comprise generally handpiece 10 of generally tapered cylindrical configuration an having extending from one end thereof coaxially with the axis of th handpiece 10 a spindle 11 which extends to jaw members (not shown which in this case constitute surgical scissors. The handpiece 1 consists essentially of two semi-cylindrical hollow handgrip member 12 and 13 respectively. The handgrip members 12 and 13 are pivotall mounted adjacent one end thereof to a central support member 14. Th handgrip members are connected to the central support 14 b respective pins 15. The shape of the central support member 14 is more evident i Figures 2, 3 and 4 and it has a number of protrusions which provid support for the various components of the instrument as will b evident hereinbelow. The spindle 11 comprises an outer shaft 16 an an inner shaft 17 which is rotatably inserted in an axial bore of th outer shaft 16. The inner shaft 17 extends into the handpiece 1 beyond the inner end of the outer shaft 16 as is evident in Figure 1 The spindle 11 is supported in the central support member 14 b passing through bore 18 in boss 19 and the inner shaft 17 also passe through bore 20 in boss 21. A stop member 22 is formed on the oute shaft 16 and bears against the end of the boss 19. A first lever member 23 is mounted on the outer shaft 16 and second lever member 24 is mounted on the inner shaft 17. The leve members 23 and 24 are fixed to the respective shafts. A spring 2 acts between the first and second lever members 23 and 24 to for them apart whereby pressure is maintained on the jaw members (n shown) constituting the respective jaws of surgical scissors attach to the end of the spindle 11. The jaw members are attached to t inner and outer shafts 16 and 17 respectively whereby rotation of t shafts in opposite directions causes the jaw members to open a close in a scissors type action. The spring 25 comprises 10 turns standard round wire permacrome of .2 mm diameter (Cat. No. 211-08 - A - Unitek Corporation, Monrovia, CA, 91016. In the case of a surgica instrument in the form of forceps the spring 25 is omitted since i is not necessary to maintain a force between the jaw members as i the case with surgical scissors. As mentioned above, the handgri members 12 and 13 are pivotally attached to the central suppor member 14 by pins 15. In order to bias the handgrip members apart as shown in Figur 1, a spring member 26 is provided on shaft 27 which fixes the sprin member 26 to the central support member 14. The spring member 26 ha opposite arms 28 which bear against the inside surface of th respective handgrip members 12 and 13 and are positively located i position by respective pins 29 which pass through apertures 30 in th ends of the respective arms 28. The spring member 26 is more clearl shown in Figures 10 and 11. In Figure 6 there is shown one of the handgrip members 12 wit U-shaped engagement member 31 for engaging with the first leve member 23 for the purpose of rotating the outer shaft 16. A simila engagement member is fixed to the other of the handgrip members 1 for the purpose of actuating the second lever member 24 to rotate th inner shaft 17. As will be evident, when the surgeon squeezes th handgrip members 12 they move towards each other symmetrically an thereby, via engagement members 31 and respective lever members 2 and 24 rotate the outer and inner shafts 16 and 17 respectively i opposite directions. This causes symmetrical actuation of the ja members (not shown). It should be further evident that by havin coaxial rotational shafts, it is possible to fit the inner shaft 1 within the outer shaft 16 with minimal clearance whereby rotation i readily effected without allowing the pasage of any fluids within th clearance space between the two shafts. The components of the surgical instrument are formed o stainless steel grade 316 and the various parts are joined wher appropriate by being silver brazed together. Any dimensions shown i the drawings are in millimetres. It will be further evident tha pivotal movement of the handgrip members 12 and 13 away from eac other is restricted by the ends of the respective members at th pivotal end beyond the pivoting point, bearing on an end stop 3 formed as part of the central support member 14. It should be noted that the present invention as describe herein provides an improved surgical instrument which ha considerable advantages over prior art instruments known to th applicant. For example, the cylindrical shape of the handpiece 1 allows the surgeon to readily rotate the handpiece between th fingers in the event that it is necessary to rotate the jaw member during the performance of an operation. Furthermore, the symmetrica movement of the handgrip members 12 as well as the symmetrica movement of the jaw members (not shown) minimizes or abolishe movement of the instrument away from the central longitudinal axi of the instrument during operation. In other words, as opposed to a instrument where only one part or side of the handpiece and one o the jaw members moves, while the other is stationary, the presen instrument is unique and much more easily controlled. The fact tha the cutting or gripping action of the jaw members reproduces th action of the fingers in compressing the handgrip members togethe simplifies use of the device and gives the surgeon a much mor precise "feel" of the action which is being performed. This i contrary to the known collett type instruments which involve a linea movement to the shafts by way of coaxial sliding action to caus opening and closing of the jaw members. In addition, the precis interfitting of the coaxial shafts and the arrangement of jaw member thereon eliminates an internal cavity which is accessible b intraocular fluids and therefore the need for complicated and time consuming cleaning internally of the spindle 11 is avoided. Th equal and simultaneous movement of both the jaw members and th handgrip members allows the instrument to be precisely positioned a held in a very steady position during use. This symmetrical moveme minimizes disturbance from the central longitudinal axis whi greatly improves control during use of the instrument. As will be evident the jaw members can be varied to provi differing surgical instruments such as forceps, scissor and clam and it is conceivable that other types of jaw members may also utilized.

Claims: WE CLAIM: 1. A surgical instrument including a handpiece (10) comprisin two parts (12) connected for relative movement towards and away fro each other, a spindle (11) extending from said handpiece to functional tip comprising jaw members at an end of the spindle remot from said handpiece, said spindle comprising coaxial shafts (16,17 each connected to a respective handpiece part and a respective ja member whereby said relative movement of the handpiece parts causes via said shafts, relative movement of said jaw members towards o away from each other, characterized in that, said handpiece is o generally cylindrical configuration split longitudinally to provid said two parts which are connected, towards one end thereof, fo symmetrical pivotal movement towards each other under pressure fro the user and away from each other under internal bias whereby sai symmetrical movement of the handpiece parts causes symmetrica movement of said jaw members by causing rotation of said shafts i opposite directions. 2. A surgical instrument as defined in claim 1, characterize in that, said handpiece is of tapered generally cylindrica configuration, said one end being the narrower end of said taper each of said two, parts being of hollow generally semi-cylindrica configuration and*said internal bias being provided by a spring (26) 3. A surgical instrument as defined in claim 2, characterize in that, an axially extending support member (14) extends centrall along the length of said handpiece and said handpiece parts are eac pivotally connected to said support member adjacent said one end an said coaxial shafts are rotationally mounted on said support membe at the other end of said handpiece. 4. A surgical instrument as defined in claim 3, characterize in that, first (23) and second (24) lever members are fixed to th outer and inner of said coaxial shafts, respectively, each lever co operating with a respective one of said handpiece parts to cause sai rotational movement of the respective shaft upon said movement of th handpiece part. 5. A surgical instrument as defined in claim 4, wherein sai instrument is a micro-surgical scissors instrument, characterized i that a compression spring (25) is provided between said lever member to bias said levers axially apart so as to maintain a mating forc between the respective jaw members so as to provide a scissors typ action. 6. A surgical instrument as defined in claim 5, characterize in that each said lever engages a forked engagement member (31) i the respective handpiece parts for the purpose of said co-operatio therewith.

Inventors: PERICIC LJUBOMIR, PERICIC, LJUBOMIR
Applicants: UNIV MELBOURNE, THE UNIVERSITY OF MELBOURNE
Application year: 1990
Main classification: A61B17
IPC codes: A61B17, A61F9