Abstract:
A drape assembly is provided for maintaining a sterile field around a surgical microscope. A drape has a first opening for receiving a protruding adapter connected to a lower end of the microscope and a collar is mounted in the first opening. An adhesive portion of the collar secures the drape to the adapter. The adapter becomes part of the optical system and may be referred to as an optical component.

Description:
SPECIFIC DATA RELATED TO THE INVENTION  
       [0001]     This application claims the benefit of U.S. Provisional application No. 60/719,022 filed Sep. 21, 2005. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a surgical microscope drape assembly and, more particularly, to a drape which maintains a sterile field during the performance of a surgical procedure.  
         [0004]     2. Background Art  
         [0005]     Stereoscopic microscopes are used extensively in surgical environments and, in particular, during eye surgery. These microscopes are typically large and cumbersome assemblies that are maintained in operating room environments although it is impractical to sterilize these microscopes. Accordingly, various types of surgical drapes have been developed to cover non-sterilized areas of the microscope while still allowing surgeons and staff to adjust the instrumentation and use such an optical assembly without interference from the drape.  
       SUMMARY OF THE INVENTION  
       [0006]     In one form of the invention, a drape assembly is provided for maintaining a sterile field around a surgical microscope. A drape has a first opening for receiving a protruding adapter connected to a lower end of the microscope and a collar is mounted in the first opening. An adhesive portion of the collar secures the drape to the adapter. The adapter becomes part of the optical system and may be referred to as an optical component.  
         [0007]     A method is also provided for fabricating a drape assembly of the type used to provide a sterile field around a surgical microscope. In one embodiment, the method includes providing a pliable sheet with a first opening formed in the sheet, and also providing a rigid collar with a second opening formed therein. The collar includes an area having an adhesive layer formed thereon. The collar is attached along the opening formed in the sheet to position the collar opening within the first opening and position the adhesive layer for attachment to an optical component.  
         [0008]     A method of maintaining a sterile field around a surgical microscope is also provided. In one example the method includes providing a drape for covering the microscope, with the drape including a collar having a first opening through the drape for receiving an adapter. The collar includes a flap with a surface having an adhesive formed thereon. The adapter is attached to a lens housing of the microscope and the collar is passed along an exterior portion of the adapter so that part of the adapter extends through the collar opening. The flap of the collar is attached to the adapter or the optical component with the adhesive. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     Features of the invention will be best understood when the following detailed description is read in conjunction with the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a perspective view of a Binocular Indirect Ophthalmo-Microscope Stereoscopic Diagonal Inverter (BIOM/SDI) system;  
         [0011]      FIG. 2  illustrates a surgical microscope incorporating a (BIOM/SDI) system;  
         [0012]      FIG. 3  is a plan view of a drape assembly according to the invention;  
         [0013]      FIG. 4A  is a plan view of a collar according to the invention;  
         [0014]      FIG. 4B  is a view in cross section, taken along line A-A′ of  FIG. 4A , further illustrating features of the collar;  
         [0015]      FIG. 5  is a perspective view illustrating a drape assembly; and  
         [0016]      FIG. 6  illustrates a surgical microscope after a BIOM is attached according to the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     In the field of ophthalmic surgery, it is common to attach optical devices to conventional microscopes in order to further increase magnification, invert images, and facilitate stereoscopic viewing by a surgeon. One such device is a Binocular Indirect Ophthalmo-Microscope Stereoscopic Diagonal Inverter (BIOM/SDI) system.  FIG. 1  illustrates a BIOM/SDI system  10  comprising a Binocular Indirect Ophthalmo-Microscope (BIOM)  13 , a stereoscopic diagonal inverter (SDI)  14 , a connection cable  15 , and a conventional BIOM adapter  16 . Normally, all of the foregoing elements, except the SDI, are sterilized before being brought into the sterilized operating room environment.  FIG. 2  is a photograph of a surgical microscope  1  incorporating a BIOM/SDI system  10 . The microscope  1  comprises a lens housing  11 , a pair of ocular ports  12 , the BIOM  13 , the SDI  14 , the optical cable  15  connecting the BIOM  13  and the SDI  14 , the BIOM adapter  16 , a power cable  17 , and a switch cable  18 .  
         [0018]     According to the invention, a surgical drape fits around the microscope  1  after the adapter  16  is installed, providing an opening through which the BIOM/SDI can be attached to the microscope  1  without compromising the sterility of the surgical field. After installation of the adapter  16 , the adapter may be adjusted and then tightened into a desired position on the lens housing  11  using a thumbscrew  19 . Additional openings may be provided to access the ocular ports  12 , and to route cabling such as the power cable  17  and the switch cable  18 . The adapter  16  has a circular portion that circumscribes the lens opening of the microscope and a rectangular extension that is normally provided with a dovetail to engage a mating member on the lower end of the lens housing.  
         [0019]      FIG. 3  illustrates an exemplary microscope drape  20  according to the invention. The drape  20  is formed of a pliable transparent plastic sheet  21  having an opening  22 . The opening  22  is sized to receive a support collar  23  having of a ring portion  24  and an adjoining tab or flap  25 . The ring portion  24  fits along the opening  22  and includes a ring opening  26  through which the adapter  16  may pass. The opening  26  is sized to fit around the circular portion of the adapter  16  in a manner which provides acceptable isolation between the non-sterile portion of the microscope and the portion of the adapter  16  exposed to a sterile operating room environment.  
         [0020]     In this example, the opening  26  of the support collar  23  is concentrically aligned with the opening  22  in the drape  20 . The support collar may be permanently bonded or removably attached to portions of the plastic drape  21  adjoining the opening  22  using known techniques such as an adhesive coating. With the size of the opening  26  providing a mating fit with the adapter  16  there remains sufficient clearance to allow the support collar  23  to pass about the adapter  16  and bring the flap  25  against the rectangular extension of the adapter  16 . As more fully described below, the flap  25  is removably attachable to the adapter  16  extension. The support collar  23  may be produced from thin cardboard or a plastic material, e.g., 3-10 mils in thickness. When attached to the adapter  16 , the collar  23  provides enough structural support to retain a portion  31  of the drape  20 , in the region of the drape adjoining the opening  22 , to be held about the adapter  16  or against the lens housing  11 .  FIGS. 4A and 4B  illustrate the structure of the collar  23 , comprising the ring portion  24  and the flap  25 . A portion of the side  33  of the flap  25  which comes into contact with the adapter  16  is covered with an adhesive layer  32 . In this example, a peripheral region  34  of the flap  25  does not have the adhesive layer  32  formed thereover. That is, the peripheral region  34  provides a non-stick area along an edge  35  of the flap  25  which can be easily grasped for removal of the collar from the lens housing  11  and adapter  16 .  
         [0021]     Prior to use of the microscope drape  20 , the entire adhesive layer  32 , or even the entire side  33 , is covered with a removable cover, e.g. peel-off paper or plastic cover  28 . With the cover  28  installed, the adhesive layer  32  may be protected from the environment prior to use of the drape  20  but can be quickly deployed by removal of the cover.  
         [0022]     The drape  20  can be designed to fit a wide variety of microscopes. The support collar  23  may be of a design allowing for its use in different sized drapes and drape openings and with adapters or other devices of varying size. That is, the ring portion  24  of the collar  23  can be formed of a material or a design which allows the opening  26  to be expanded. For example, the opening  26  may be formed in a cardboard collar with radial slits allowing portions of the cardboard along the opening to be displaced as an adapter of slightly larger diameter than the opening is passed through the opening. Alternately, the ring portion  24  may be formed of a deformable or elastic material allowing the opening  24  to be stretched to a larger size. The drape  20  has additional openings  29  at various locations, e.g., to pass eye pieces, cables or cords, of the microscope through the drape  20 . Such openings may be formed with peel-off covers  30  to retain a barrier between the sterile environment and the non-sterile region within the drape when the openings are not required to provide a function.  
         [0023]      FIG. 5  illustrates the surgical drape  20  positioned at an initial stage of installation on the microscope  1  with the adapter  16  (which may have been sterilized) having already been installed on the lens housing  11 . At this stage the adapter  16  may be tightened into position on the lens housing  11  using the thumbscrew  19  provided on the adapter, although readjustment may be desired after the drape  20  is installed. With the adapter  16  positioned on the lens housing, in a method of maintaining a sterile field around the surgical microscope  1 , the support collar  23  is passed along the adapter  16  such that the adapter protrudes through the collar opening  26  and the side  33  of the flap  25  faces the extension of the adapter  16 . The cover  27  is peeled off of the adhesive layer  32  on the side  33  of the flap  25 . The flap  25  is then pressed upward and against a surface of the adapter  16  extension. This action secures the portion  31  of the drape  20  so that it does not fall downward along the adapter and over the ocular attachments that are to be connected to the adapter  16 , e.g., the BIOM  13 . As illustrated in  FIG. 6 , the drape is positioned to cover the microscope  1  and is wrapped against the microscope  1  and a post  40  to which the microscope is attached by tying a sterile tie strap  36  thereabout. The adapter  16  provides a sterile attachment point for additional optics to be used during ophthalmic surgery. With this arrangement the sterile BIOM  13 , also shown in  FIG. 6 , is attached to the adapter  16 , allowing surgical staff to proceed to work in a sterile field. When additional openings with peelable covers are provided, e.g., to access the ocular ports  12  and openings for cables, the openings are positioned to receive these optical and electrical elements and the covers are removed accordingly.  FIG. 6  shows the ocular ports  12  tied with sterile straps  37  after the covers are removed.  
         [0024]     While one embodiment of the invention has been illustrated and described, the invention is not so limited. Many variations or improvements can be made without departing from the spirit and scope of the invention which is only limited by the claims which follow.