Patent Application
20170231612
The disclosure relates generally to a medical device used during hip replacement surgery, and more particularly as a device for elevating the proximal portion of the femur during minimally invasive hip replacement surgical procedures.
Total hip replacement has been one of the most commonly performed surgical orthopedic procedures and has been regarded as among the most valued advances in the history of orthopedics. It has been remarkably successful in replacing hip joints destroyed by degenerative disease, trauma and rheumatoid arthritis. Recently there have been significant advancements in the surgical techniques allowing the performance of implant insertion through minimally invasive smaller skin incisions using the anterior approach. In order to approach the hip joint anteriorly, the operating surgeon must use specialized instruments and retractors which will be inserted through much smaller incision anteriorly as compared to much larger incisions of conventional lateral or posterior approaches. This is technically challenging and more demanding since the operative field is small and compared to a deep hole. Several specialized retractors are commonly used to provide retraction and distraction of the muscles and tissue. Once the femoral head and neck are osteotomised and removed, the operating surgeon will then ream and clean the femoral intramedullary canal in preparation for the insertion of the femoral implant. Reamers and broaches are used to clean the medullary canal. During said reaming, the surrounding muscles and soft tissues are subjected to significant undue trauma and injury. Often, the operated leg is placed in extension and external rotation by lowering the foot portion of the operative table. This simply does not bring the proximal portion of the femur cut side the wound to allow the surgeon the ream the medullary canal without causing undue damage and attrition to the adjacent muscles and soft tissue.
When hand held retractors are used to raise the proximal femur to facilitate reaming of the medullary canal, they will be levered against the edge of the wound causing significant damage and maceration of the skin and subcutaneous tissue. They will apply undue pressure onto the surrounding muscles causing unrepairable damages. Other lifting means use electrical motor in a form of a winch to jack up the proximal femur in order to expose its proximal end through the wound. Said means are expensive and attached to the table as part of the frame. There is usually one motor attached to the right side of the table and one to the left side of the table. This system poses sterility concerns since the moving post has to penetrate through the drapes.
Another form of mechanical femoral elevator is available in the industry designed by Richard Wixson, where lifting of the femur is accomplished by an overhead unit attached to the table, comprising a vertical and horizontal rods as well as femoral hook attached to a T handle bolt. When said bolt is turned the hook will raise the proximal femur. However, said overhead elevator is bulky, cumbersome and prone for contamination during the surgical procedure due to its size and height as well as proximity to the overhead surgical light. Furthermore, said overhead elevator stands in the way of the surgeon increasing and may come too close to the non sterile overhead operating light thereby significantly increasing the chance of contamination. Other electromechanical device are solidly attached to the main frame of the specialized surgical table and remain non sterile. Their vertical shaft has to penetrate and violate the sterile draping representing a significant contamination concern. Furthermore. Since the device is permanently attached to the table, it cannot be used with any other conventional and commonly used surgical tables.
While these devices may be suitable for the particular purpose to which they address, they are not suitable for providing non-traumatic simplified method for elevating the proximal femur through minimal skin incision during total hip joint replacement.
A major improvement provided by the present invention is a simple mechanical jack and simplified femoral hook attachment. The device is easily attached over the sterile surgical drapes to the right or left sides of the surgical table and providing proximal femoral lift without any traumatic leverage against the edge of the wound and without any bulky and cumbersome overhead suspended device. Furthermore, the device will not interfere and stand in the way of the surgeon. Additionally, the hook is curved and shaped to contour the bone in a way that avoid any undue pressure and injury to the muscles and surrounding tissue.
During hip replacement surgery, the hip joint is routinely dislocated and the femoral head must be elevated and lifted out of the wound in order to prepare it for implantation. The head is transected and the proximal femur is raised and supported outside the wound using various hand held elevators and retractors, which often apply undue damage and injury to the surrounding soft tissues and muscles since they rely on surrounding soft tissue for leverage in order to support the femur. Other available elevators on the market are space occupying and too bulky. They provide traction from above to lift the proximal femur. However, they stand in the way and interfere with the ability of the surgeon to adequately access the wound. In view of the forgoing disadvantages inherent in conventional femoral lifting devices, the present invention provides a new mechanical jack, which provides strong lifting mechanism to the proximal portion of femoral bone allowing it to be raised and protrude through the surgical wound in order for the operating surgeon to ream and prepare the proximal femur for the insertion of the femoral stem. Said insertion would be very difficult if the proximal portion of the femur remains deeply imbedded in the surgical wound. Excessive pulling of the bone using retractors may result in fracture of the bone, which represents a considerable undesired complication.
The general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new mechanical jack comprising a gearbox, which will be firmly attached over the sterile drapes to side rails of any conventional operating table. A vertical shaft passing through the gearbox and having a hook at its upper end. Said hook is passed under the proximal femur and lesser trochanteric region. The new system has many of the advantages of the conventional femoral elevating tools and many novel features that are not anticipated, rendered obvious, suggested or even implied by any of prior art conventional devices, either alone or in any combination thereof.
To attain this, the present invention generally comprises a main gearbox containing a plurality of gears. At least one of the gears making contact d engages with the gears of the vertical shaft passing through the main gearbox. Furthermore, a crank handle can be inserted into the small gear through a side opening. The vertical shaft having gear teeth that will engage with the large gear located in the main gearbox in order to provide the appropriate lifting mechanical advantage. The main gearbox can be slidingly attached via dovetail retention grooves to a fixation device attachment comprising two clamps. Said clamps can be firmly attached to the side rails available on all conventional operating tables. The proximal upper end of the vertical shaft provide a T shaped joint having an circular hollow channel allowing the horizontal shaft and femoral bone hook to be slidingly adjusted according to the patient's size. A rotating joint is interposed between the horizontal and vertical shaft to allow rotation freedom.
Various objects, features and advantages of the present invention will become fully appreciated as the same become better understood when considered in conjunction with the accompanying drawings, in which the same reference number is used throughout the several views to refer to an identical or similar, wherein:
Turning now descriptively to the drawings, in which similar references characters denote similar elements throughout the several views, the attached figures illustrate a mechanical elevating femoral jack and attachment device suitable for elevating the proximal end of the femur outside the surgical wound in order to allow the operating surgeon to perform the necessary preparation of the femur for insertion of the trials prior to implanting the prosthesis.
Furthermore, the main gearbox is firmly attached to the side rails of any conventional operating table using a fixation attachment as seen in
It is to be understood that the above description is intended to be illustrative and not restrictive. Although numerous characteristics and advantages of various embodiments as described herein have been set forth in the foregoing description, together with details of the structure and function of various embodiments, many other embodiments and changes to details will be apparent to those of skilled in the art upon reviewing the above description. For example, some or all of the gearbox and fixation attachment can he made out of ceramic, radio opaque plastic or metallic alloy. Other embodiment made out of recyclable plastic will allow the device to be disposable and intended for single use. Therefore, the scope of the invention should be, determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
