Abstract:
A surgical file instrument including a surgical file assembly having an elongated tubular member with a guide/shield supporting the blade of the surgical file and being formed on the distal end thereof, the guide/shield portion being generally planar shaped and having an elongated longitudinally extending dimple defining a rail for guiding said blade and keeping it central and preventing wobbling. The side edges of said guide/shield extend upwardly and bear against the underside of the blade for supporting the same.

Description:
RELATED APPLICATIONS 
     This application is a continuation application of U.S. application Ser. No. 12/586,092, filed Sep. 17, 2009, entitled “SURGICAL FILE” which is related to U.S. Pat. No. 8,388,622 filed Sep. 17, 2009, entitled “SURGICAL FILE INSTRUMENT CONSTRUCTION WITH MECHANISM TO CONVERT ROTARY MOTION TO RECIPROCAL MOTION,” both invented by David Narducci, Stephen Bucina, Michael Menard and Eddy Del Rio, the entire disclosures of which are hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a surgical file instrument that is used in a surgical procedure for removing bone from a patient. More particularly, the invention relates to the file and guide/shield portion for cutting, removing, grinding, shaping and sculpturing bone and to the configuration of the file, and guide/shield to assure that the reciprocating file remains centered when being used and precludes any wobbling motion. 
     2. Description of Related Art 
     There are a number of surgical file instruments that are commercially available and as one skilled in this art appreciates, it is abundantly important that the blade of the file of the surgical file instrument when in operation remains centered and does not vacillate from that plane. In other words, the file must remain within its operating plane and stay along the center line for precision bone removal. Moreover, the file blade must be shielded so that the portion of the anatomy that isn&#39;t being worked on is not inadvertently cut or bruised. The file must be dimensioned so that it can be used in very tight and close areas in the body that are typically difficult to get to in order to perform precision surgical operations. 
     There are commercially available surgical file instruments that have a sundry of applications that may be used by a surgeon for the treatment of certain types of pathology. For example, U.S. Pat. No. 7,390,330 (&#39;330) granted to Harp on Jun. 24, 2008 essentially relates to a surgical file instrument that is similar to the surgical file instrument described in the present patent application, however, the invention described in this patent application patentably distinguishes over the surgical file disclosed in the U.S. Pat. No. 7,390,330 (&#39;330), supra. The &#39;330 patent, supra, discloses a shielded reciprocating surgical file system and allows a user to navigate the file into hard to access parts of the patient&#39;s body. It also describes a transmission mechanism that converts rotary motion from a motor into reciprocating motion, pump mechanism and an irrigation system that supplies fluid to the surgical site. 
     In one embodiment in the &#39;330 patent, for example, the cutting blade is shielded on five sides to provide a shielded surgical file. The file can be dimensioned so that it extends generally straight, curved, angled or bent along the longitudinal axis. The file needs to be compatible to fit into the human or mammalian anatomy portions. Its thickness must be thin so that it fits into small spaces such as between a nerve and the foramen opening that it is passing through and the cutting blade can be shaped or contoured. The present invention is capable of performing these types of operation with a less complicated file. In other words, the present invention is characterized as being relatively simple to, make, less costly and yet, it is efficacious. 
     To obtain the reciprocal motion from the rotary motion, the structure disclosed in the &#39;330 patent, supra, utilizes a torus transmission device which may include an integral shaft or a rigidly connected shaft. The torus drive and drive shaft are rotatable about a central rotation axis and has a generally circular or curvilinear cam portion with the torus central axes being at an offset angle. The variable thickness of the torus cam surface produces a hybrid dual or twin torus. Similar to what is disclosed in the &#39;330 patent, supra, the present invention has utility for many medical procedures that are typically the concern in neurosurgery, orthopedic surgery and plastic surgery, amongst others. For example in neurosurgery, the neruroforamen may need enlargement and the file can be instrumental in removing rigid bony vertebral structure to allow the nerve roots to pass there through. In orthopedic surgery the knee may require sculpturing. And, in plastic surgery bone and tissue sculpturing may be required for nose reshaping and rhinoplasty. 
     It is imperative in this type of surgical file instrument that the file blade doesn&#39;t wobble or get out of line while being used. To this end we have found that by contouring the central portion of the guide/shield with a dimple having an apex bearing against the underside of the blade and providing a unique configuration to the side portions of the dimple extending from the apex in which the file blade is in sliding relationship, the surgical file and blade remain in a fixed plane during its reciprocating condition. 
     While this invention provides the configuration for assuring that the file remains in-line, this feature is in combination with a surgical file instrument that includes a specific motion converter having a planetary gear system and a cam with a thrust control as well as having a file assembly that includes an elongated outer tube casing, a file having an elongated angular shaft portion having a blade on the distal end and a tang on the proximal end and an encapsulated elongated cylindrical solid tube of plastic material. The solid tube is formed with an elongated generally “infinity symbol” shaped aperture and lumens extending in a longitudinal direction. The “infinity shaped” lumen serves as a passageway for the shaft of the surgical file and the other lumens serve to define passageways to access the surgical site. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to provide an improved surgical file. 
     A feature of this invention is to provide for a surgical file an improved configuration of the shield for the file wherein the central portion thereof is formed with a dimple that is in sliding relationship with the file. 
     Another feature of this invention is the outer tube casing that fairs into a flattened portion at the distal end that lies in contiguous relation to the file blade and defines a guide and shield therefor. 
     A feature of this invention is the combination of a motion converter that converts rotary to reciprocal motion, a surgical file assembly that includes a longitudinally extending dimple formed in the guide/shield that is in sliding relationship with the file blade in order to insure that the blade remains in-line during its reciprocating condition. The motion converter includes a planetary gearing system, cam, dome and thrust control and the surgical file assembly includes a longitudinal extending tube case, a longitudinally extending solid insert in said tube case and a longitudinally extending file in said solid insert. 
     The foregoing and other features of the present invention will become more apparent from the following description and accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exploded view in perspective illustrating the invention; 
         FIG. 2  is an assembled view in section of the surgical file instrument depicted in  FIG. 1 ; 
         FIG. 2A  is a sectional view taken along lines  2 A- 2 A if  FIG. 2 ; 
         FIG. 3  is a partial enlarged view in perspective and section illustrating the motion converter of this invention: 
         FIG. 4  is an enlarged view in perspective of the drum depicted in  FIG. 3 ; 
         FIG. 5  is an exploded view in elevation illustrating the file assembly of this invention; 
         FIG. 6  is an enlarged partial view in perspective of the file, the file blade, the file shield and the file assembly; 
         FIG. 7  is a sectional view taken along lines  7 - 7  of  FIG. 6 ; and 
         FIG. 8  is a sectional view taken along lines  8 - 8  of  FIG. 6 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As shown in the preferred embodiment of this invention, the configuration of the file assembly wherein the outer tube casing includes a solid plastic tube that describe a particular shape and number of lumens, as will be appreciated by those skilled in this surgical file instrument technology, the shape and numbers of lumen may vary without departing from the scope of this invention. The same is true for the various dimensions and angles of the file assembly which may take the form of non-angularly shaped configurations, and the size including the width and thickness will well depend on the anatomy of the patient being operated on. The types of blades of the file may be different from the one depicted in the preferred embodiment, as for example, it may include abrasive cutting surfaces instead of the micro-holes that are shown in this application. 
     The invention can best be seen by referring to  FIGS. 1-4  which show the surgical file instrument generally illustrated by reference numeral  10  comprising the outer split casing  12 , the battery  14 , electric motor  16 , the motion converter  18 , and the file assembly  20 . In the assembled condition as seen in  FIG. 2 , the casing  12  is formed in two generally cylindrical members  22  and  24  that are suitably attached by the screws  26  threadably engaging the threaded lugs  28 . The terminals  30  and  32  connect the motor  16  to the battery  14  for powering the motor and driving drive shaft  34 . In turn, the drive shaft  32  provides rotary motion to the motion converter  18 , as will be described in detail herein below. As noted in  FIG. 2 , the drive shaft  34  attaches to the coupler  36  which, in turn, is coupled to the driven shaft  38  of the planetary system  40  of the motion converter  18  for rotating the same. As will be explained below, the planetary gear system  40  rotates the cam  42  and via the follower (see  FIG. 3 ), which, in turn, translate the drum  46  and shaft  48  to impart reciprocal motion. The file assembly  20  includes the file  50  having an angular shaft  52 , a blade  54  and tang  56 . Tang  56  includes hole  58  (see  FIG. 5 ) that cooperates with a complementary threaded hole  60  formed in the bifurcated end portion  62  (see  FIG. 3 ) and with a suitable bolt  62  (not shown) fitted into hole  58  is threaded to hole  60  connects the file  50  to drum  46  for imparting reciprocating the file. As is obvious, the casing is split into two halves to gain access to the connection between the file assembly and the dome of the reciprocal converting mechanism. 
     It is typical in this type of these types of instruments to provide irrigation to the surgical site. To this end, the casing  12  includes port  42  and the lubricant transmittal tube  44  that is connected to the lumen  46  formed in the file assembly  20 . 
     The next portion of this application will describe the inventive cam/drum configuration of the motion converter  18 . The stub shaft  66  is suitably connected to the drive shaft  34  of motor  16  and carries pinion gear at the distal end thereof (The connection may equally be made by a direct connection without the use of a stub shaft). Pinion gear  68 , in turn, meshes with each of the planetary gears  70 , (three in number) which, in turn, meshes with the fixed ring gear  72 . Ring gear  72  is fixed to the cam outer casing  73  via the dowel pin  75  disposed in the slot  77  formed in the flange  79 . (The ring gear can be made integral with the cam outer casing). As is apparent from  FIG. 3 , each of the planetary gears  70  are rotary supported to stub shaft  74  which is suitably pinned to platen  76 . Platen  76  is a portion of the rotating cam  78  which is rotated by the spinning planetary gears  70 . Cam  69  includes the main body  71  that has formed therein the cam slot  80  that is designed to produce reciprocal motion as will be apparent from the following description. Follower  44  fitted into the cam slot  80  is pinned via pin  86  to drum  88 . As noted, and in accordance with this invention, a single cam follower is all that is necessary to drive drum  88 . Drum  88  comprises the hollow sleeve  90  (see  FIG. 4 ) having the aperture  92  formed on the peripheral side thereof. The follower  44  consists of stub shaft  94  locks roller  96  to the hollow sleeve  90  via the recess  98 . A washer  100  may be used to assure that the roller has sufficient spacing so that its rolling around shaft  94  is not impaired. In accordance with this invention, two (2) thrust pins  102  and  104  fit into annular groove  106  formed in the cam. The thrust pins  102  and  104  are grounded to the cam casing  108  and serve to absorb the thrust loads so as to allow the efficient operation of the surgical file. 
     In operation, the motor drives shaft  66  and pinion gear which, in turn, meshes with the three (3) planetary gears  70  which, in turn, meshes with the fixed ring gear  72 . This reaction of all of the above mentioned gears rotates the cam  69  via the platen  76 . The platen  76  which is integral with the cam  69 , as a consequence, is rotated. This motion, in turn, is converted to reciprocal motion via the follower  44  that drives the drum in a reciprocal motion. Obviously, this motion is translated to the surgical file by the connection described above. 
     Also, in accordance with this invention the surgical file is unique as will be described in detail herein below. As mentioned above the file assembly comprises a longitudinally extending outer tube  112  that has formed thereon at the distal end a flat or planar shaped shield and guide member  115 . A longitudinally extending solid rod  114  is tightly fitted into tube  112  formed with the “infinity shaped” slot  116  and a pair of lumens  46  and  47 . (See  FIG. 2A ) And a generally longitudinally extending file  50  that fits into the infinity slot  116  and extends beyond the distal end of the solid rod  114  wherein the blade is complimentary dimensioned to the guide/shield and portions of the lower surface thereof are contiguous to portions of the upper surface of the guide/shield and in sliding relationship in the longitudinal direction. In its preferred embodiment, the elements in the surgical file assembly are bent 30 degrees adjacent to the proximal end and at the same angle adjacent to the distal end. Obviously, the particular shape and dimensions of the elements in the surgical file assembly will be predicated on its particular use. 
     As shown in  FIGS. 6-8 , the cutting surface of the blade  54  of file  50  consists of a plurality of radial projecting ring-like elements or micro holes  120  that serve as cutting edges  122 . As mentioned earlier, the particular file head is not a concern of this invention. However, of importance is the shape of the guide/shield  115  and its relationship to the file head. Formed on shield  115  is the elongated dimple  124  extending longitudinally along the central portion of shield  115 . The dimple includes the apex  126  and the straight slopes  128  and  130  extending from the top portion along either sides there of. This particular configuration defines a rail that centers the file and keeps its motion in a linear straight line which obviously, is important for the delicate types of precision operations to which the surgical file instrument is used. The lower portions  119  and  121  of the shield  115  extend radially toward the outer edges of blade  54  of the file  50  and are bent slightly upwardly to be in contiguous contact with the side edges of blade  54  of the file  50 . As is apparent from the foregoing the guide/shield provides an efficient support for the blade  54  of the file  50  while assuring that the tissue or body parts adjacent to the operation site are not bruised or injured. 
     Although this invention has been shown and described with respect to detailed embodiments thereof, it will be appreciated and understood by those skilled in the art that various changes in form and detail thereof may be made without departing from the spirit and scope of the disclosed invention.