Abstract:
A three-prong retractor is disclosed which is inserted into an incision in a patient in order to create an area for surgery. The retractor opens such that two blades move away from a first blade to create an elongated opening. The two blades may then move away from each other in a direction that intersects the direction of the movement of the first blade away from the two blades. The ends of the two blades remote from the retractor body may then move away from the end of the first blade remote from the retractor body to further open the incision. The retractor may also have an elastomeric sheath surrounding the blades in order to create a barrier between the surgical area and the patient&#39;s skin.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   The present application claims benefit of U.S. Provisional Application No. 60/642,234, filed Jan. 7, 2005, the disclosure of which is hereby incorporated by reference herein. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a device used to retract the tissue of the body of a patient during surgery. More specifically, the present invention relates to a retractor that facilitates enlarging a surgical cavity and providing access to a surgical site. 
   Invasive surgical procedures require a surgeon to create an incision in the patient&#39;s skin in order to access the area within the patient&#39;s body where the surgery must be performed. It is desirable for the surgeon to create a small incision because a smaller incision takes less time to heal and thus causes less trauma to the patient. The incision, however, must be large enough to accommodate the surgeon&#39;s tools necessary to perform the surgery. Thus, retractors are often used to hold open incisions in order to hold a patient&#39;s skin wide open for surgery and prevent the skin from entering the surgery area while the surgeon operates his or her tools. 
   Retractors as known in the art typically consist of two opposing prongs that enter into an incision and extend away from each other in order to pull the skin of the patient back into a large opening. These retractors pose two problems: the opening created by the retractor is an elongated opening that is usually not large enough to accommodate a plurality of surgical tools, and there is no protection of the skin from the surgical area which may lead to the slippage of surgical tools on to the skin of the patient. Thus, a need exists for a surgical retractor that provides a large surgical work area from a small incision and creates a boundary between the surgical area and the patient&#39;s skin. 
   The present invention addresses these needs by facilitating a larger surgical cavity for surgery through a smaller incision which minimizes tissue trauma. This minimally-invasive approach provides faster patient rehabilitation than traditional incision and retraction techniques. 
   The various embodiments of the present invention are particularly useful for orthopedic surgery of the spine, but are envisioned to be limitlessly applicable to other surgical techniques and other parts of the body. 
   SUMMARY OF THE INVENTION 
   In a preferred embodiment the present invention is a retractor comprising a first supporting member, a second supporting member coupled to said first supporting member for selective translational movement of said first and second supporting members towards and away from each other, a holding arm connected to said second supporting member on an axis, a medial blade attached to said first supporting member having a distal end remote from the first supporting member, and a pair of lateral blades attached to said holding arm, each of said lateral blades having a distal end remote from said holding arm, said holding arm facilitating movement of said ends toward and away from each other in a plane that intersects the direction of the translational movement of said first supporting member and said second supporting member. The holding arm preferably rotates such that the distal ends of the lateral blades rotate away from the medial blade. An actuator may facilitate this rotation. 
   In one aspect, the medial blade and the lateral blades are preferably surrounded by a sheath. The sheath may be an elastomeric sheath made of silicone rubber. The sheath may be partially transparent or translucent. 
   In a further aspect, the medial blade and the lateral blades are pivotally connected to the first supporting member and the holding arm. The blades may be made of a polymer or of aluminum. The blades may be of different lengths for a particular surgery. For example, the lateral blades may be shorter than the medial blade or the medial blade may be shorter than the lateral blades. In one embodiment, the distal ends of the blades may be tapered. One or more of the blades may be curved in a horizontal plane. 
   In another embodiment, the present invention is a retractor comprising a first supporting member, a second supporting member coupled to the first supporting member, a holding arm connected to said second supporting member on an axis, a medial blade attached to said first supporting member at a proximal end and having a distal end remote to the first supporting member, a pair of lateral blades attached to said holding arm, each of said lateral blades having an end remote from said holding arm, means for moving the second supporting member away from the first supporting member, and means for moving the ends of the lateral blades away from each other. The retractor may also comprise means for rotating the ends of the lateral blades away from the end of the medial blade. 
   In this embodiment, the medial blade and the pair of lateral blades are preferably surrounded by a sheath, which may be an elastomeric sheath. 
   In another aspect of this embodiment, the medial blade is shorter than the pair of lateral blades. 
   In yet another aspect, the present invention comprises a method of retracting tissue from an incision for surgery comprising the steps of inserting three blades of a retractor having one medial blade having an end and two lateral blades having ends into an incision, actuating the retractor to move the medial blade away from the two lateral blades, actuating the retractor to move the ends of the two lateral blades away from each other, and actuating the retractor to move the ends of the two lateral blades away from the end of the medial blade. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1A  is a top perspective view of one embodiment of a retractor according to the present invention. 
       FIG. 1B  is a bottom perspective view of the retractor depicted in  FIG. 1A . 
       FIG. 2  is an enlarged perspective view of the connection between the medial blade of the retractor and the first supporting member. 
       FIG. 3  is a top perspective view of the retractor in a translated position. 
       FIG. 4  is a top perspective view of the retractor with the lateral blades rotated in the sagittal plane. 
       FIG. 5  is a top perspective view of the retractor with the lateral blades rotated in the sagittal plane and transverse plane. 
   

   DETAILED DESCRIPTION 
     FIGS. 1A and 1B  depict one embodiment of the versatile frame retractor according to the present invention in a closed position for insertion into an incision. The medial blade  10  is attached to a first supporting member  20 , which is coupled to the second supporting member  25  with a rack member  30  and crank  35 , or other expedient as known in the art. The second supporting member  25  is connected to the holding arm  26 , which holds the first retaining member  27  and the second retaining member  28 . The first lateral blade  40  and second lateral blade  50  are held by the first retaining member  27  and the second retaining member  28 . The first lateral blade  40  and second lateral blade  50  are positioned against the medial blade  10  for ease of insertion of the retractor into a small incision. The medial blade  10  is preferably shorter than the lateral blades to better accommodate the anatomy of the spine; specifically the arch of the lamina and the greater depth of the transverse process. The three blades are preferably surrounded by an elastomeric sheath  60  which prevents tissue from entering the surgical site while the surgeon is working. The frame retractor further comprises a central drive screw  70  and a second drive screw  80 . 
   The medial blade and the lateral blades are preferably curved in the horizontal plane as best seen in  FIG. 3  so that the blades exert less stress on the tissue while the retractor is in the opened position. In addition, each of the blades may have a small lip or tapered end where they are to be inserted into tissue to prevent the blades from slipping out of the tissue while the retractor is in use. 
     FIG. 2  is an enlargement depicting the connection of the medial blade  10  to the first supporting member  20 , which includes a key slot with a rectangular channel communicating with a round opening. The medial blade  10  includes a post with a round head, the post including flats which permit the post to be entered into the rectangular slot. The medial blade  10  can then be rotated and captured in the round opening. The first lateral blade  40  and the second lateral blade  50  are connected to the first retaining member  27  and the second retaining member  28  in the same or a similar fashion, though it is recognized that any suitable expedient can be practiced. Alternatively, one or more of the blades may be integrally or permanently attached to the respective portions of the frame retractor. 
   The terms “sagittal” and “transverse” as used herein refer to the orientation of the retractor with respect to the surgeon. These terms are used herein for convenience only. One skilled in the art would recognize a plurality of options for positioning the retractor in a patient depending on the type of surgery and preference of the surgeon. In this application, “sagittal plane” means that the ends of the blades are rotated away from each other in a plane that intersects the direction of the translational movement of the first supporting member  20  and the second supporting member  25 . The term “transverse plane” means that the ends of the lateral blades  40 ,  50  are rotated away from the end of the medial blade  10  in the same direction that the first supporting member  20  and the second supporting member  25  are translated away from each other. 
   The blades  10 ,  40 , and  50  of the retractor are preferably easily removable. This allows a surgeon to replace the blades with longer or shorter blades as the surgery and/or anatomy requires. In addition, easy removal of the blades provides for sterilization or disposability. Thus, a surgeon may be provided with a kit of variably sized and shaped blades from which desired blades may be selected for a particular surgery or technique. Additionally, disposability of the blades allows for easier post-use handling techniques. 
   To use the retractor, the surgeon makes a small incision in the skin of the patient and inserts the distal ends of the blades, meaning the ends of the blades that are not attracted to the body of the retractor, into the incision. The retractor is preferably in a closed position as shown in  FIG. 1A  when inserted into the incision. Once the blades of the retractor are inserted into the incision, the crank  35  may be rotated to translate the second supporting member  25  away from the first supporting member  20  as depicted in  FIG. 3 . This will force the lateral blades  40 ,  50  away from the medial blade  10  and open the incision in preparation for surgery. As seen in  FIG. 3 , the elastomeric sheath  60  is flexible and will stretch to keep unwanted tissue out of the surgery area and protect the skin outside the surgery area from the surgical tools. 
   To gain greater access to the surgical site, the lateral blades  40 ,  50  may be rotated in the sagittal plane by rotating the central drive screw  70  as shown in  FIG. 4 . The central drive screw is connected to an actuator that will rotate the first retaining member  27  and the second retaining member  28  away from each other. The blades will rotate within their retaining members to provide more access to the opening. 
   If a larger opening is still desired, the second drive screw  80  may be rotated to angulate the holding arm in the transverse plane as shown in  FIG. 5 . The second drive screw  80  facilitates this rotation. The larger opening created by this rotation will provide the surgeon with a relatively large, clear view of the surgical site. 
   It is recognized that the central drive screw  70  and the second drive screw  80  may be engaged by a tool, such as a screwdriver, an Allen wrench, or any other suitable tool that will facilitate rotation. Additionally, it is envisioned that multiple variations of the type of tool, the interface with the screw, as well as screw types, or even the absence of a screw, are possible to facilitate the movement of the blades of the retractor towards and away from each other. 
   The material used in the construction of blades  10 ,  40 , and  50  is generally of a rigid type, such as plastic or metal, to support the spreading of body tissue. In a preferred embodiment, the material is radiolucent or semi-radiolucent thereby allowing for the improved visualization of the anatomy when viewed on an X-ray with the retractor in place or to carry and emit light. In other embodiments, the material may be non-autoclavable or otherwise non-sterilizable, and disposable. This further allows for the interchangeability of blades to suit particular surgical applications as well as surgical cavity sizes. 
   The elastomeric sheath  60  is preferably made of a pliable, elastic, and preferably translucent material, such as silicone rubber, and fits snugly around the blades  10 ,  40 , and  50 . Preferably, the sheath  60  is assembled over the blades when the retractor is in the unexpanded position, as depicted in  FIG. 1 . Upon opening of the retractor as depicted in  FIGS. 3 ,  4  and  5  the sheath  60  stretches and forms an enclosure around the blades  10 ,  40  and  50 . This enclosure allows for a more manageable surgical cavity by preventing tissue from entering the cavity. The sheath  60  may also be made of a transparent material, so that when in the expanded condition, a surgeon may see tissue and objects through the sheath when it is in the surgical cavity. 
   Upon the reverse translation of the central drive screw  70  and second drive screw  80  and the return of the blades  10 ,  40  and  50  to their unexpanded state, the sheath  60  returns to its original form as well. Thus, when surgery has been completed, the blades of the retractor are brought together following the opposite steps used to expand the retractor. Once the blades are completely together as shown in  FIG. 1A , the retractor may be removed from the incision. Depending on the pliability of the material used to construct the sheath, the sheath may aid in bringing the blades back to their original, unexpanded condition. In any event, the tissue surrounding the blades aids in compressing the blades back to their unexpanded condition. It should be noted that various materials with the above desirable properties for the sheath may improve the cost-effectiveness of the sheath&#39;s disposability. In addition, the sheath may be of any shape or size and may cover any area of the retractor, thereby creating any portion of covered and non-covered areas of the blades. The sheath may be interchangeable with other types of retractors, such as the surgical retractor with scissor arms disclosed in U.S. patent application Ser. No. 10/943,520, the entire disclosure of which is hereby incorporated by reference as fully set forth herein. 
   Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.