Abstract:
A pneumatically powered bone resector has a moveable cutting arm and a stationary foot against which the cutting arm homes to cut bone positioned therebetween, the cutting arm being hollow for receiving resected bone with a mechanical/pneumatic linkage connected to the cutting arm for driving the cutting arm and blowing the resected bone through the cutting arm and into a receiving bin, an electronically controlled pneumatic power supply for powering the linkage upon operation of a trigger, the trigger being operated by a surgeon.

Description:
CROSS-REFERENCE AND PRIORITY CLAIM TO RELATED APPLICATIONS  
       [0001]     This application claims priority to U.S. provisional patent application Ser. No. 60/779,400, entitled “Bone-Evacuating and Valve-Exiting Resector and Method of Using Same”, filed Feb. 24, 2006. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION  
       [0002]     Surgical tools for resecting bone are well known in the prior art. These tools are used to reach inside an incision and resect or “chip” away the bone from a patient for any one of several reasons. This process generally takes place as the patient is under some form of anesthesia which dictates that the speed of the operation be given some urgency. Furthermore, it is also the case that prior art devices require a process of continual insertion and removal of the bone resector which is not only a time consuming and cumbersome process but also provides opportunity for infection due to the possible introduction of foreign materials into the incision. For these reasons the prior art devices have been used but are not in keeping with the modernization of many surgical techniques which take these risks into account.  
         [0003]     One example of a bone resector presently in use is the Kerrison™ Rongeur. It allows a surgeon to remove sections of bone or tissue manually. The surgeon places the stop of the Kerrison rongeur (far left of  FIG. 1 ) beneath the section of bone to be resected and squeezes the handle (see  FIG. 1 ). This causes the cutting arm to rise up and, if sufficient force is applied, penetrate the bone to the depth of the curved end. The surgeon then removes the Kerrison™ Rongeur from the surgical entry, hands the cutting end of the tool to a nurse, and instructs the nurse to either keep or discard the resected bone or tissue. The nurse removes the bone or tissue fragment from the Kerrison rongeur, typically with her gloved fingers, and informs the surgeon when this task has been completed while handing the tool back to the surgeon for the next resection. The surgeon then reinserts the Kerrison™ Rongeur in to the surgical entry and the process repeats, sometimes dozens of times, until the surgeon finishes the bone resection.  
         [0004]     To eliminate the above noted shortcomings of the prior art device and its method of use, the inventors have succeeded in developing a pneumatically powered bone resector and collection device which represents a significant improvement over the prior art device. The new invention may remain in the surgical opening while multiple resections are made, power the cutting operation so that the surgeon need only place the tool and not be required to squeeze or exert hand pressure to achieve the cutting, and automatically clear the tool for the next resection by blowing the resected bone tissue into a collection container which may automatically segregate the tissue specimens into one of a plurality of collection bins. The surgeon may then finish the resection procedure swiftly upon one insertion and then removal to minimize the risk of infection, diminish the time required to completion to minimize surgical risk to the patient, and relieve the surgeon from any tiring effects on his hand which ensure a safer and more accurate procedure.  
         [0005]     The present invention is elegantly simple in design, adapted into a similar profile as that of the prior art device, both being substantially in the form of a hand held pistol for ease and accuracy of use, and will thus be readily adopted and accepted by a surgeon in his practice with little re-learning or unfamiliarity to overcome. In essence, and as explained in greater detail below, the present invention comprises a hand held device containing a trigger actuator, an air cylinder, a mechanical linkage powered by the air cylinder to drive the moveable cutting arm into the stationary foot to resect the bone therebetween, a collection box and two collection bins into which the resected bone tissue is blown, and five air lines—two of which drive the air cylinder, another air line which clears the cutting arm by blowing the bone tissue through its hollow length, and a last pair of air lines which blow the bone tissue specimen from a common sorting bin into one of a plurality of designated collection bins. Each sorting bin may contain a mechanism such as a one way valve to prevent bone chips from exiting the sorting bin, and indicators such as light emitting diodes or audio signal devices to indicate the extent to which the sorting bin&#39;s volume is filled, and thus when the bin requires emptying or replacement. The air lines are controlled by an electronic control so as to be timed with respect to each other and operate in proper sequence. Also, on the outside of the hand held tool are a toggle switch allowing the surgeon to designate the collection bin to receive the resected bone specimens and a trigger switch for the surgeon&#39;s use in making a resection once the tool is positioned as desired. If desired by the surgeon, the trigger may be partially depressed to move the cutting arm into contact with the bone prior to resecting it to ensure the desired bone area is properly targeted.  
         [0006]     As described herein, one of the objects of the invention is to provide a powered surgical bone resector. Another object of the invention is to provide a bone resector that has a pneumatically powered cutting operation, with the pneumatic supply being alternatively from a sterile gas source such as a hand held canister or filtered air from a compressor system. Another object of the invention is provide a surgical bone resector that can do multiple resections while remaining within the surgical incision. Another object of the invention is to provide a surgical bone resector that automatically collects the bone specimens being resected. Another object of the invention is to provide a surgical bone resector that can automatically sort the bone specimens that are resected into any one of a multiple number of collecting bins. Another object of the invention is to provide a surgical bone resector that after resection automatically clears the bone specimen from the cutting arm. Another object of the invention is to provide a surgical bone resector that sorts the bone specimens into multiple disposable collecting bins. Another object of the invention is to provide a surgical bone resector which can position the cutting arm adjacent a selected bone tissue prior to selectively actuating a cutting operation. Another object of the invention is to provide a system of exchangeable and replaceable cutting arms and carriers, which detach easily from the handheld carrier. Another object of the invention is to provide cutting arms and carriers optimized for field of view, targeting, reaching and cutting in general or specific surgical procedures. Another object of the invention is to provide a powered surgical bone resector that is electronically controlled. Another object of the invention is to provide a surgical bone resector that is electronically controlled with no electrical wires or connections within proximity of the patient. Another object of the invention is to provide a surgical bone resector that has an electronic control that is programmable. Another object of the invention is to provide a method of resecting a bone with a powered bone resector. Another object of the invention is to provide a method of doing multiple resections with a bone resector while the resector remains within the surgical opening. Another object of the invention is to provide various methods for using the apparatus comprising the foregoing invention objects as well as those in the claims. The foregoing objects of the invention, and others as defined by the claims appended hereto, are achieved by the preferred embodiment of the invention disclosed herein. However, the preferred embodiment is provided not as a limitation of the invention but instead is to only be considered as illustrative thereof.  
         [0007]     While several of the principal advantages and features of the invention have been discussed above, a fuller understanding of the invention may be attained by reading the following detailed description of the preferred embodiment and referring to the drawings included herein.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]      FIG. 1  is a perspective view of the Kerrison™ Rongeur bone resector of the prior art;  
         [0009]      FIG. 2  is a perspective view of the pneumatically powered bone resector of the present invention; and  
         [0010]      FIG. 3  is a cut away view of the interior assembly of the pneumatically powered bone resector of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0011]     The bone resector  20  of the present invention comprises a hand held carrier  22  preferably shaped in the form of a handgun for ease and familiarity of use by a surgeon. Inside the carrier  22  is mounted a dual action pneumatic cylinder  24  having its piston  26  connected to a mechanical linkage  28  for driving and retracting a cutting arm  30 . The mechanical linkage  28  comprises a sliding yoke  32  attached to the piston  26  with a hole therethrough which mounts the sliding yoke  32  to a guide post  34  to guide it as the pneumatic cylinder is actuated. The yoke  32  has two yoke arms  36  which are bridged by a pin  38  extending through a slot  40  in a second guide arm  42  so that as the cylinder is actuated, the piston extends to drive the yoke along the first guide post and move the pin through the second guide arm, thereby pushing the second guide arm forward to drive it forwardly of the carrier  22 . The cutting arm  30  is slidingly mounted to the top of the carrier  22  and is connected to the second guide arm  42  so that it is driven thereby. The carrier  22  has a stationary foot  46  extending upwardly at the end of the carrier  22  and against which the cutting arm  30  is driven to resect bone. The carrier  22  also has a tube, or pneumatic passage  48  along the extended forward nose  50  and through which pressurized air is blown, as is explained in greater detail below. The cutting arm  30  also has a pneumatic passage  52  in its interior, or is hollow, and which aligns with the pneumatic passage  48  as the cutting arm  30  is extended against the foot  46  so that resected bone may be blown out of the foot  46  and backwards through the cutting arm  30 . A trigger  54  is positioned on the carrier  22  in the place of an ordinary handgun trigger, and when depressed sends a signal to the electronically controlled pneumatic power supply  55  to cause a bone resection to occur and then retract. Additionally, a switch  56  is arranged beneath the trigger  54  to allow a surgeon to select where the resected bone is collected. At the back end of the pneumatic passage  48  is connected a sorting bin  58  into which the resected bone is deposited after being blown backwards from the foot  46 . The sorting bin  58  has a pair of ports  60  which are connected to pneumatic lines  62  and are arranged so that one of the other will be activated to blow resected bone deposited in the sorting bin into either one of two collection bins  64  through supply tubes  66 . The collection bins  64  are preferably “locked” into the carrier  22  similarly as ammo clips are in a handgun, again for ease of operation and familiarity of use. The collection bins  64  preferably have on their tops compliant interlocking triangular flaps of rubber or other flexible material that allow passage of bone chips into the collection bins, but not out of the collection bins.  
         [0012]     There are pneumatic lines extending preferably from the electronically controlled pneumatic power supply  55  to operate each side of the pneumatic cylinder  24 , each of the two ports  60 , and the bone resection pneumatic passages  48 ,  52 . Electrical lines extend preferably from the trigger  54  and the switch  56  back as well to the electronically controlled pneumatic power supply  55 . The power supply is controlled preferably by a programmable control, such as may be purchased from Gleason Research, Cambridge, Mass., under part no. GRHB-PC, and programmed as shown by the program in Attachment A. As would be apparent to one of ordinary skill in the art, other suitable programmable controls and options would be suitable as well. One such example would be to have the pneumatic control be under the control of a microcomputer, or the like. It is noted that with the preferred embodiment of the present invention the bone resector is electrically isolated from the patient as it is placed for bone resection within a surgical opening. The electrical wires and signals carried by to and from the trigger/switch are of low power and of no risk to any patient.  
         [0013]     The pneumatic source may be any convenient source of pressurized air. The operating pressures found by the inventors to work in the preferred embodiment are from 80 psi to 100 psi. The timing for the turning on and off of the various (5 in the preferred embodiment) pneumatic lines is controlled from the running of the operating software as found in Attachment A. However, it would be expected that those or skill in the art, with the teachings of the present disclosure, would find it discernible without undue experimentation to determine operating pressures and timing for any convenient pneumatic power source.  
         [0014]     The present invention preferably achieves bone resection by practicing the following method:  
         [0000]     (1) A “cutting arm” of a desired size is selected from the set of cutting arms provided with the invention, and clipped into place on the carrier.  
         [0000]     (2) The “collection bins” are inserted into the base of the carrier handle in the same way that an ammunition clip is inserted into the handle of a pistol.  
         [0015]     (3) The device is plugged into a base unit comprising an electronically controlled pneumatic power supply containing control electronics and a compressed air purification system preferably using a high grade sterilizing filter to remove bacteriaphage from the pneumatic lines as may be purchased from the Shanghai Apureda Industry Co., Ltd. (not shown in detail).  
         [0000]     (4) The “foot” at the cutting end of the device is placed beneath the bone to be resected.  
         [0000]     (5) The “bin selection switch” is set to direct resected bone to one of the two “collection bins” through the sorting bin.  
         [0000]     (6) If the surgeon chooses to do so, the trigger is depressed partially, allowing the cutting arm to contact the bone to be resected prior to cutting.  
         [0000]     (7) The trigger is depressed fully, and the following set of actions follows:  
         [0000]     (7a) A valve in the base unit sends pressure to the “pneumatic cylinder” 
         [0000]     (7b) The pneumatic cylinder is actuated to drive the piston, which extends the yoke to ride up the “guide post”, pushing the “second guide arm”, which in turn pushes forward the cutting bar  
         [0000]     (7c) The cutting arm slices through the bone, entrapping a bone chip between its forward tip and the foot  
         [0000]     (7d) The control unit sends air through the base of the cutting arm to blow the bone chip away from the foot and backward through the handle  
         [0000]     (7e) The bone chip is blown into the sorting bin, and then through the pre-selected supply tube to its associated collection bin, using the air powered sorter when needed  
         [0000]     (7f) The control unit sends a signal to the cylinder to retract the piston, thereby allowing the mechanical linkage and cutting arm to retract to return to a home position to ready for another resection  
         [0000]     (8) The surgeon repeats this process any number of times, without having to remove the device from the surgical entry, by depressing the trigger again each time  
         [0000]     (9) When resection is complete, the “collection bins” are removed from the handle. Bone chips and tissue are removed from the bins, and the bin is either discarded or sterilized for reuse.  
         [0016]     While the preferred embodiment has disclosed a preferred form and method of practicing the invention, there are changes, modifications, and alternatives that would be apparent to those of ordinary skill in the art and which are within the scope of the present invention. As such, the present invention should be considered as limited only by the scope of the claims appended hereto and their legal equivalents.