Abstract:
A microsurgical system, and a foot controller for the improved operation of a microsurgical system, are disclosed. A surgeon may use the foot controller to proportionally control a surgical parameter based upon the amount of force applied to a pressure plate of the foot controller.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally pertains to surgical systems. More particularly, but not by way of limitation, the present invention pertains to foot controllers for the operation of such systems. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Various foot controllers are used to control surgical systems, and particularly ophthalmic microsurgical systems. During ophthalmic surgery, a surgeon views the patient&#39;s eye through an operating microscope. To control the microsurgical system and its associated handpieces during the various portions of the surgical procedure, the surgeon must either instruct a nurse how to alter the machine settings on the surgical system, or use the foot controller to change such settings. Where possible, many surgeons prefer to use the foot controller to alter the machine parameters or settings on the surgical system, eliminating the need to converse with a nurse during the surgical procedure. Most prior art foot controllers have a hinged upper surface which is movable through a range of motion. An encoder within the foot controller is able to detect the exact position of the upper surface and provide either linear or non-linear proportional control of surgical parameters. However, the use of such foot controllers requires the surgeon moving the foot pedal through a possibly wide range of motion, and can prove uncomfortable for a surgeon to use, particularly during extended surgical procedures. In addition, such a foot controller would not be desirable if the surgeon has limited ankle mobility. Finally, such position sensing foot controllers are expensive to manufacture, and can be quite large and heavy. 
         [0003]    Therefore, a need continues to exist for an improved foot controller, for use with powered microsurgical devices, that is compact, inexpensive to manufacture, and can be comfortably and reliably controlled by the surgeon. 
       SUMMARY OF THE INVENTION 
       [0004]    In a preferred embodiment, the present invention comprises a method of providing proportional control of a parameter in a microsurgical system. The microsurgical system has a computer, a foot controller operatively coupled to the computer, and a surgical parameter. The foot controller has a pressure plate and a force sensor coupled to the pressure plate. An amount of force applied to the pressure plate is determined. A value of the surgical parameter is proportionally controlled as a function of the force applied to the pressure plate. 
         [0005]    In another embodiment, the present invention comprises a microsurgical system having a computer, a foot controller operatively coupled to the computer, and a surgical parameter. The foot controller has a pressure plate and a force sensor coupled to the pressure plate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]    For a more complete understanding of the present invention, and for further objects and advantages thereof, reference is made to the following description taken in conjunction with the accompanying drawings in which: 
           [0007]      FIG. 1  is a schematic view of a microsurgical system according to a preferred embodiment of the present invention. 
           [0008]      FIG. 2  is a top perspective view of a foot controller of a microsurgical system according to a preferred embodiment of the present invention. 
           [0009]      FIG. 3  is a cross sectional view of a foot controller of a microsurgical system according to a preferred embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0010]    The preferred embodiments of the present invention and their advantages are best understood by referring to  FIGS. 1 through 3  of the drawings, like numerals being used for like and corresponding parts of the various drawings. 
         [0011]      FIG. 1  shows a microsurgical system  10  according to a preferred embodiment of the present invention. As shown in  FIG. 1 , microsurgical system  10  is an ophthalmic microsurgical system. However, microsurgical system  10  may be any microsurgical system, including a system for performing otic, nasal, throat, or other surgeries. System  10  has computer  11  disposed therein. System  10  is capable of providing ultrasound power, pneumatic drive pressure, irrigation fluid, and aspiration vacuum to microsurgical instrument  12 . Instrument  12  may be any microsurgical instrument necessary for performing otic, nasal, throat, or other surgeries, but is most preferably an instrument to be used in either anterior or posterior segment ophthalmic microsurgery, such as a laser, diathermy probe, a phacoemulsifier, vitreous cutter, powered scissors, powered forceps, or powered fluid injector. Surgical instrument  12  is operatively coupled to system  10  via interface  14 . A foot controller  26  is operatively connected to surgical system  10  via interface  28 . Interfaces  14  and  28  may be conventional electronic cable or standard surgical tubing as dictated by the requirements of instrument  12 . 
         [0012]      FIGS. 2 and 3  show a preferred embodiment of foot controller  26 . Foot controller  26  has a body  48  with a base  49  that supports foot controller  26  on the operating room floor. Body  48  preferably includes a pressure plate  52 , heel rest  54 , and a handle  64 . Force sensor  50  is disposed within the body and mechanically coupled to pressure plate  52 . Pressure plate  52  may be made of any appropriate material but is most preferably made of a lightweight inexpensive material, such as aluminum. Force sensor  50  may be any appropriate device, but is most preferably a strain gauge or a force sensing resistor such as the FLEXIFORCE® force sensing resistor available from Interlink Electronics or Tekscan, Inc. of Boston, Mass. Force sensor  50  is electrically coupled to interface  28 . Interface  28  is, in turn, electrically coupled to system  10 . As shown in  FIG. 3 , shield  60  may be coupled to body  48  to partially enclose pressure plate  52 . Shield  60  serves to protect foot controller  26  from accidental actuation. 
         [0013]    During operation, the surgeon proportionally controls a surgical parameter related to the operation of a surgical handpiece by applying pressure to pressure plate  52 . Such pressure slightly deforms force sensor  50  causing an electric signal to be generated that is proportional to the applied pressure. This electric signal is transmitted to surgical system  10  via interface  28 . Computer  11  of system  10  then proportionally controls a surgical parameter of instrument  12  as a function of the amount of force applied to pressure plate  52 . Such proportional control may be in either a linear or non-linear fashion. 
         [0014]    It is believed that the operation and construction of the present invention will be apparent from the foregoing description. While the apparatus and methods shown or described above have been characterized as being preferred, various changes and modifications may be made therein without departing from the spirit and scope of the invention as defined in the following claims.