~0697~9 . . .
- This invention relates to surgical retractors and, more particularly, the invention relates to a unique sternum retractor.
Durlng open-heart and other thoracic surgery, it is often necessary to divide the sternum (sometimes referred to as the breastbone) and to spread both sides of the divided bone structure to expose the underlying chest cavity. The divided sternum is then held in the spread condition until the surgery has been completed.
Surgical retractors heretofore used for thoracic surgery have usually included a U-shaped frame having two generally parallel blade-supportlng arms mounted for relative ~0~ 7~ coD-26 movement on a support member. A plural~ty of retractor blades were individually secured to the arms and moved in unison ln substantially parallel planes when the ~upport arms were moved relative to one another. Thus, the sternum and the bone structure surrounding the sternum were separated and held in a separated conditlon by substantlally parallel retractor blades. Unfortunately, since the sternum normally separates at an angle, the prior sternum retractors have created unnecessary forces on the bone structure o~ the sternum and the surrounding tiBBUe .
Another characteristic of prior sternum retractors iB that they have traditionally been constructed totally from stainless steel or some other suitable metalllc material. During the open-heart, or thoracic surgery, it is often de~irable, especially in the final stages of the surgery, to take X-rays of the operative field. Because of the radiopaque properties of the steel it has previously been necessary to completely remove the sternum retractor in order to facilitate the X-ray procedure. This has been an inconvenient and time consuming operation.
Summary of the Invention In accordance with one aspect o~ the present invention9 there is provided a sternum retractor having a generally U-shaped con~iguration formed by an arm support and two :10697139 CoD-26 ~ubstantially parallel arms supported thereon. One of the arms is secured near one end of the arm support and the other arm i8 movable on the arm support relative to the first arm. An elongated blade support member is pivotally secured to each of the arms at a single selected locatlon along the length of the re~pective arm. Each blade support member has a plurality of retractor blades secured thereto and the blade support members ~ace one another on the inside of the U-shaped ~rame. Because of this unlque single pivot configuration, the retractor blade~ are free to follow the natural contour o~ the ~ternum and surroundlng bone structure when the divided sternum ls separated to expose the underlylng chest cavity.
This is made possible by the fact that there is a single pivot point for the blade support member and the blades are mounted on the support member in such a way that they will contact the sternum and follow the angular opening o~ the cternum to avold undue trauma to the sternum and surrounding tissue.
In accordance wlth another aspect of the invention, the entire blade support member and retractor blade are constructed of a radiotransparent plastic material. m is unique ~eature makes it possible for the surgeon to take any desired X-ray picture6 without removing the retractor blades ~rom the operative site.
~ - 3 --` ~069789 According to a still further broad aspect of the present invention, there is provided a sternum retractor which comprises an arm support, and two arms mounted for movement relative to one another on the arm support. Means is provided for effecting the said relative movement. At least one aperture extends through each of the arms. A pair of blade supports are also provided and a bifurcated projection extends from each of the blade supports having apertures therethrough in alignment with the apertures of the arms. A removable locking pin extends through the apertures in each bifurcated projection and the respective arm apertures to provide a single pivot point to secure the blade supports to the arms. A plurality of retractor blades are secured in spaced relation on each of the blade sup-ports.
10~9789 COD-26 Therefore, it is a prlmary ob~ect of this invention to provide a sternum retractor wherein the retractor blades are mounted in such a way a5 to permit them to follow the natural contour of the ~ternum when it is ~eparated ln the traditional manner to expose the unaer-lying chest area.
A further ob~ect is to provide a unique sternum retractor which facilitates the taking of X-rays without the removal of the retractor from the operative site.
Other ob~ects and many attendant advantages of the invention will become more apparent when consldered ln connection with the specification and accompanying draw-lngs wherein:
Fig. 1 is a perspective view of a surglcal field illu~trating the unique sternum retractor of the present invention in contact with the divided sternum;
Fig. 2 is a perRpective view illustrating the assembly of one of the retractor blade support~ onto its respective support arm;
Fig. 3 i8 a cross sectional view taken along line 3-3 in Fig. l;
Fig. 4 is a cross sectional view taken along line 4-4 in Fig. l;
Fig. 5 is a cross sectional view taken along line 5-5 in Fig. 1, and Fig. 6 is a cross sectional view taken along line 6-6 in Fig. 5.
CoD-26 10~9~7~9 Descr~ption o~ the Preferred Embodiment Fig. 1 illustrates the unique sternum retractor of the present invention shown generally at 10. Retractor 0 i8 illu~trated in position on both sides of a divided ~- sternum S with the che~t cavity C exposed therebelow.
Retractor 10 is formed with a generally U-shaped frame having an arm ~upport 11, a stationary arm 12 secured near one end thereo~ and a movable arm 13 mounted for movement relative to the stationary armO Movable arm 13 1~ secured to a carriage 14 which, in turn, is movably mounted on arm support 11.
Referring to Figs. 5 and 6, carrlage 14 has a housing 16 through which arm support 11 extends. The upper side 17 of housing 14 has a lower surface 18 which is generally planar and is designed to slide on the upper sur~ace 20 o~ 15 support arm 11. The lower sur~ace of support arm 11 is provlded wlth a plurality of teeth 21 to ~orm a rack.
pinion 23 having spaced teeth 24 adapted to mesh with teeth 21 i~ mounted for rotation on carriage 14 by a sha~t 25. A
bifurcated crank 26 is secured to shaft 25 by a pi~ 27 &nd i~
e~fective to rotate pinion 23 to thus cause a relative move-ment between arm 13 and arm support member 11.
Thus ~ar, the U-shaped frame structure described above i~ similar to frame~ heretofore used for supporting sternum retractor blades. m e ~ollowing description will describe the unique structure of the present invention and point out the advantage~ derived therefrom.
1069789 CoD-26 Referring to Figs. 1 and 2, the upper ends o~
arms 12 and 13 have spaced apertures 31 and 32, respectively, extending therethrough. Apertures 31 and 32 are provided to permit selective location o~
the unique retractor blade assembly shown generally in Fig. 2 at 35.
Blade assembly 35 comprises an elongated blade support member 36 having at least two curved blades 37 and 38 secured thereto. A bifurcated pro~ection 39 extends outwardly from blade support member 36 and has apertures 40 extending therethrough for alignment with apertures 31 on arm 12 and apertures 32 on arm 13.
As will be seen in Fig. 2, bi~urcated pro~ection 39 is adapted to be positioned over arm 12 at any one o~ three selected positions and is held in place by a locklng pin 42. Referring to Fig. 3, blade assembly 35 is shown ln positlon relative to arm 12 and the two elements are ; locked together by locking pin 42 which passes through any one o~ the apertures 31 extending throu~h arm 12.
A~ter the pin has been positioned through the uniquely formed apertures, it is only necesRary to rotate the pin 90 to firmly lock all of the elements together. Thus, it will be seen that the retractor blade assembly can be easily positioned relative to arm 12 by merely removing pin 42 and replacing lt at the desired location. As a result of this unique construction, it is possible to con~truct a blade assembly from a relatively inexpensive 1()~97~9 CoD-26 plastic material so that the entire blade assembly ~nd locklng pin can be disposed of subsequent to any surgical procedure. Although the retractor blade assembly 36 has not been described in detail, it will be appreciated that the blade assembly i~ essentially identical to blade assembly 35 and i8 positioned and held in place relative to arm 13 in a manner identlcal to that described with respect to retractor blade aSsembly 35.
Referring to Fig. 4, the inner surface of curved retractor blade 37 is lllustrated ln detail. A plurality of dome-shaped members 45 extend outwardly from the 8ur-face of the retractor blade to enhance the gripplng effect of the blade relative to the underlying sternum surfaces.
In order to utilize the unique sternum retractor of the present invention, arms 12 and 13 are ~laced in an initial po~ition ad~acent one another by moving carrlage 14 to the left as shown in Fig. l. Blades 37 and 38 and the corresponding blades 46 and 47 on blade assembly 36 are placed into the open chest cavity on opposite sides of the divided sternum and surrounding bone structure.
Normally a surgical drape is interposed between the retractor blade and underlying body surfaces. Crank 26 may then be rotated to thereby rotate pinion 23 and cause carriage 14 and arm 13 which is secured thereto to move in a direction to the right as viewed in Fig. 1 of the drawing.
CoD-26 As will be seen in Fig. 1, the individual blade as~emblies are free to rotate about a single pivot point which is formed by locking pins 42 which connect the blade assemblies to arms 12 and 13. Consequently, the retractor blade a~semblie~ are free to con~orm to the natural contour of the dlvided sternum as the sternum and surrounding bone structure is separated to uncover the underlying chest cavity. A~ lllustrated ln Figure 1, blade aæsembly 35 iB shown with its blade supporting member 36 substantially parallel to arm 12.
Whereas, blade support member 45 on retractor blade assembly 36 is at a subatantial angle to the plane of arm 13. There~ore, the individual retractor blade~ 46 and 47 are at a different distance from arm 13. Obviously, blades 37 and 38 could also be at different distance~ from arm 12 but have been shown equidlstant for purposes of illustratlon only.
Although the entire sternum retractor may be made o~
stainless steel or other suitable noncorrosive biocompatible material, the retractor blade assembly is pre~erably made from a radiotransparent plastic material such as, nylon.
AB previously st~ted, it is frequently desirable to take X-rays of the operatiYe field subsequent to certain proce-dures. Consequently, it is desirable to be able to retain the retractor blade assemblies in position during the taking of such X-rays. This eliminates the necessity of having to CoD-26 1~)6~7~9 r~move the blades and then having to reinsert them if it i8 nece~sary to perform further manipulative proce-dures.
It will be apparent from the foregoing description that the present invention provides a unique sternum retractor which operates in a manner superior to prior retractors. The present invention permits retraction of a divided sternum by retractor blades that follow the natural contour of the sternum during the separation of the sternum and surrounding bone ~tructure. ThiB con-structlon reduces any trauma that may have been occasioned by prlor retractors which were deslgned to divlde the sternum by using retractor blades that open in lines substantially parallel to one another. In addition, the unique retractor blade assemblies have been constructed of radiotransparent plastic material which will ~acilitate the taking of X-rays prior to the removal of the retractor from the patient~s body. Also these retractor blade assemblies, since they are made from a p~astic m~terial, will be readily dispoRable following any given surgical procedure.