WO2003073945A1

WO2003073945A1 - Bone chip harvesting trap

Info

Publication number: WO2003073945A1
Application number: PCT/CA2003/000279
Authority: WO
Inventors: George K. B. Sandor; Robert P. Carmichael; Donald R. Johnson; Vesa Tapani Kainulainen; Kyosti Sakari Oikarinen
Original assignee: Sandor George K B; Carmichael Robert P; Johnson Donald R; Vesa Tapani Kainulainen; Kyosti Sakari Oikarinen
Priority date: 2002-03-07
Filing date: 2003-03-04
Publication date: 2003-09-12
Also published as: AU2003208202A1

Abstract

In accordance with the invention a device for harvesting bone fragments includes a canula and a gathering housing. The gathering housing defines an internal chamber and includes an outlet port and an inlet port. The inlet port is adapted to receive one end of the canula. The chamber also includes at least one screen located within the chamber so that fluid flowing from the inlet port to the outlet port passes through the at least one screen. The invention also extends to the use of the device explained above to collect bone material suitable for bone grafting procedures.

Description

Title: BONE CHIP HARVESTING TRAP

FIELD OF THE INVENTION

[0001] This invention relates to the field of medical devices. In particular, the invention relates to an apparatus and method for collecting bone material that may be used for reconstructive surgery involving bone grafts, particularly in human beings.

BACKGROUND OF THE INVENTION

[0002] There are many medical procedures involving bone grafts. Bone grafts are often required where there has been trauma or other injury to a bone and it becomes necessary to rebuild the damaged bone at the selected site. In other cases, bones may not have developed and it may be desired to repair or augment existing bone even bones that have not been altered or impaired by disease or external or other causes. In many cases, material suitable for bone grafting is generated by exposing bone and cutting chips from the bone. The chips cut from the bone are then used at the selected grafting site. While various methods and procedures exist for creating appropriate sized chips and for gathering those chips for use at the selected site, it is apparent that improved methods and equipment for collecting bone material suitable for use in conducting bone grafting procedures would be advantageous.

SUMMARY OF THE INVENTION

[0003] In accordance with the invention, a device for harvesting bone fragments includes a canula and a gathering housing. The gathering housing defines an internal chamber and includes an outlet port and an inlet port. The inlet port is adapted to receive one end of the canula. The chamber also includes at least one screen located within the chamber so that fluid flowing from the inlet port to the outlet port passes through the at least one screen.

[0004] In accordance with another aspect, the invention includes a method of collecting bone material using the apparatus described above, including the steps of generating bone fragments suitable for use in bone grafting, collecting the bone fragments by drawing the bone fragments into the device described above and collecting the bone fragments drawn into the device on the at least one screen.

[0005] In accordance with a further aspect of the invention, the invention includes a method for obtaining bone material suitable for bone grafting at a selected site including the steps of generating bone fragments suitable for use in bone grafting, collecting the bone fragments by drawing the bone fragments into a device as outlined above and collecting the bone fragments drawn into the device, on the at least one screen.

[0006] Further and other aspects of the invention may be appreciated from review of the following detailed description of an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The invention will now be discussed in association with the following embodiment of an apparatus made in accordance with the invention and in which:

[0008] Figure 1 is a cross-sectional view through an embodiment of an apparatus constructed in accordance with the invention;

[0009] Figure 2 is a cross-sectional view through one of the components illustrated in Figure 1 ; [0010] Figure 3 is a sectional view through a portion of the component shown in Figure 2 within the circle 3 but in enlarged scale;

[0011] Figure 4 is a cross-sectional view through another component shown in Figure 1;

[0012] Figure 5 is a cross-sectional view through a portion of the component illustrated in Figure 4 within the circle 5 but at enlarged scale, and

[0013] Figure 6 is a section through a third component shown in Figure

1.

DETAILED DESCRIPTION OF THE INVENTION [0014] The bone harvesting apparatus is shown generally at 10. The bone harvesting apparatus 10 comprises a canula 12 and a gathering housing 14.

[0015] The gathering housing 14 comprises an outlet port 20 defined by a generally cylindrical wall 22. The generally cylindrical wall 22 is adapted to receive a tube which conveniently may be standard surgical tubing. The surgical tubing is connected to a source of medical vacuum pressure. In use, the source of medical vacuum pressure creates a vacuum within the gathering housing 14. [0016] The gathering housing 14 defines an internal chamber 24. The internal chamber 24 is comprised between two cup-like portions, a downstream cup 26 and an upstream cup 28. The cup-like portions 26 and 28 may be joined together through any convenient means such as interacting threads or by using a clamp or series of clamps, a separate ring or the like. In the embodiment illustrated, the cup-like portions 26 and 28 are press fit together as explained more fully below.

[0017] The downstream cup 26 includes the outlet port 20 and the cylindrical wall 22. The upstream cup 28 includes an inlet aperture 30 which is sized to receive the canula 12. Advantageously the inlet aperture 30 and the outlet port 20 are arranged along the general axis of symmetry of the gathering housing 14.

[0018] The gathering housing 14 includes first or downstream screen

40 and a second or upstream screen 44. The two screens may be captured between the cup portions 26 and 28 or otherwise located within the chamber inlet 24. These screens filter material flowing from the inlet aperture 30 toward the outlet port 20.

[0019] The first screen 40 is located in the downstream position and is intended to retain the bone material on the screen which is drawn into the internal chamber 24. The material for the screen itself may be relatively fine. It is suggested that a 60 x 60 mesh 43 of suitable material having openings in the range of 0.107 or 3,600 holes per square inch will be suitable to retain the bone material. The mesh 43 can be captured between a pair of rings 41 and 42 which are illustrated in Figure 6. The upstream screen 44 is similar to the first or downstream screen 40. A relatively coarse mesh is suggested for the upstream screen. Thus, the upstream screen may be a 40 x 40 mesh having 0.17 openings or approximately 1 ,600 holes per square inch. The second screen 44 is similar to the first screen 40 with the mesh being captured between a pair of rings 45 and 46 which are similar to rings 41 and 42. The rings 41 , 42, 45 and 46 all have the same outer diameter. [0020] The downstream cup 26 includes a cylindrical wall 50 having an internal cylindrical surface 52 and an external generally cylindrical surface 54 with a land 56. The rings 41 , 42 and 45, 46 of first screen 40 and second screen 44, respectively, are received within the cylindrical wall 50 and bear against the internal cylindrical surface 52 and a land 58. The upstream cup 28 includes a cylindrical wall 60 having an internal cylindrical surface 62. From reference to Figures 2 and 3, it will be noted that the generally cylindrical surface 54 has a raised portion 53 having a slightly greater diameter. From reference to Figures 4 and 5, it will be noted the generally cylindrical surface 62 includes a downstream portion 63 having a comparatively larger diameter, a conical shoulder 64 and an upstream portion 65 having a comparatively smaller diameter. The upstream cup also has a shoulder 66. The raised portion 53 of the downstream cup 26, bears against the internal cylindrical surface 65 of the upstream cup 28. The interference fit between the raised portion 53 and the surface 65 maintains the downstream cup 26 and the upstream cup 28 in registry, with the upstream cup 28 being drawn against the land 56. The land 66 bears against the ring 46 of second screen 44. This effectively holds the first and second screens in position as illustrated in Figure 1. The larger diameter portion 63 and the conical shoulder 64 facilitate alignment of the cups 26 and 28 as they are assembled. [0021] The upstream cup 28 additionally includes a passageway 70 which extends from the internal chamber 24 through the wall of the upstream cup 28.

[0022] The downstream cup 26 includes a valve indicated generally at 80. The valve can be moved from the closed position shown in Figure 1 to an open position wherein the gallery 82 communicates with the outlet port 20. The valve 80 is principally an on-off valve. When the valve is in the position shown in Figure 1 , the suction generated by the suction line attached to the outlet port 20 is sealed at the valve so that no fluid is drawn into the canula 12. When the valve 80 is in the fully open position, the full suction force available from the suction supply line affixed to port 20 is available to draw fluid into the canula 12. By positioning the valve 80 between the full open and full closed position, some throttling can occur to vary the suction pressure directed to the tip of the canula 12. [0023] In use, the device is used by attaching surgical tubing so as to align with the outlet port 20. This may be conveniently done by inserting the cylindrical wall 22 within the surgical tubing. The surgical tubing is then attached to a medical source of vacuum pressure so as to create a vacuum pressure within the internal chamber 24. When the valve 80 is in the open position, the vacuum pressure then draws fluid into the canula 12 so that the fluid passes along the canula 12. Fluid will also be drawn in through passageway 70. All fluids drawn in to internal chamber 24 will pass first through the upstream screen 44 and then through the downstream screen 40. Advantageously, downstream screen 40 is a finer screen while upstream screen 42 is a larger screen. This arrangement of screens provides a classification of material on the two screens with larger material being retained by the upstream, coarser screen 44 and finer material being retained on the downstream, finer screen 40.

[0024] The bone harvesting device 10 is particularly useful to assist in gathering bone material for use in bone grafting procedures. The method of using the device involves first setting up the device as indicated above with a surgical suction tube attached to the outlet port 20 which in turn is attached to the external vacuum source.

[0025] The next step in utilization of the device is the creation of desired bone chips. These bone chips may be created at a surgical site of a patient by drilling, scraping or sawing on the bone which is available. This drilling, scraping or sawing can be part of the surgical procedure at the selected site such as an osteotomy which may involve preparing the selected site for the installation of various types of hardware including an implant. The surgical procedure may also involve use of the device 10 at a separate harvesting site, with the wound of the harvesting site being distant from the selected site of the bone grafting procedure. As the bone chips are generated with a suitable tool, the site is irrigated with saline solution. A member of the surgical team will then use the bone harvesting device 10 to aspirate the saline soaked chips of bone into the device 10 by means of the vacuum within chamber 24.

[0026] Since contaminants can find their way into the surgical field when the bone is being harvested, such as saliva in the mouth or mucus in a paranasal sinus, it is advantageous to be able to vary the intensity of the vacuum pressure at the end of the canula 12 of the device 10. Accordingly, a function of the passageway 70 is to provide the member of the surgical team holding the device 10, the opportunity to change the suction pressure by covering and uncovering the passageway 70 with a finger without the need to move valve 80. When it is desired to have a lesser suction pressure at the tip of the canula 12, such as may occur when the surgical field is contaminated with saliva or mucus for example, the member of the surgical team could move a finger away from the passageway 70, thus allowing air to enter the internal chamber 24 and thereby decreasing the suction pressure at the surgical site. This allows the member of the surgical team to be more selective with what material is aspirated into the device 10 which may assist in avoiding gross contamination of the collected material with potentially infected debris. On the other hand when the surgical field is less contaminated, the person holding the device 10 can cover the passageway 70 with a finger and utilize comparatively increased suction pressure to draw in the bone chips as desired.

[0027] As the suction continues to draw material into the canula 12, the fluid and bone material which is desired is drawn along the canula 12 into the internal chamber 24 and then passed through upstream screen 44, through downstream screen 40 and out through outlet port 20. Depending upon the size of the screening selected for the upstream and downstream screens, comparatively large particles are retained on upstream screen 44, while smaller particles are retained on downstream screen 40. Advantageously, the screen sizes are selected so that blood clots and other undesirable material which may be drawn into the canula, are retained on upstream screen 44 and desirable material comprising the bone chips suitable for use in grafting purposes are retained on downstream screen 40. [0028] If for any reason there should be a cessation or slow down in the generation of bone material to be aspirated into the chamber after the bone material generation procedure has begun, it may be desirable, to ensure that there is no additional flow of fluid along the canula 12. Continuous flow of air along the canula 12 can result in drying out of the bone graft material which is retained on screen 40. Such drying out or desiccation can cause perishing of many bone cells within the collected material. This effect can be reduced by closing the valve 80 to minimize any unwanted flow in the canula 12 and passageway 70. An additional feature of the passageway 70 is that saline solution or other fluid may be directed into the chamber 24 as desired. Fluid injected through passageway 70 will pass through both screens 44 and 40.

[0029] When the bone harvesting operation has proceeded far enough or when the screens 40 and/or 44 are becoming full, the harvesting action is stopped. The vacuum source can be either shut off at valve 80 or the suction line may be disconnected from the outlet port 20. The device 10 may then be disassembled by removing the cup 28 from cup 26 providing access to the upstream screen 44. Upon removal of the upstream screen 44, the screen may be cleaned with the material retained thereon being discharged to waste. The downstream screen 40 may then be removed and all of the bone material retained on that screen may be harvested, collected and readied for use at the bone grafting site. [0030] As illustrated in the drawings herein, the bone harvesting collection device 10 comprises a first screen 40 for connecting bone graft material and a second upstream screen 44 for filtering out other unwanted material. It is not necessary that an upper screen 44 be utilized if conditions do not require. When an upstream screen 44 is not required, a simple filler ring having the same dimensions radially and axially as the rings 45 and 46 combined, may be substituted for the screen '44. Of course, if additional screens are required, these can be utilized. In such a case the housing would have to be elongated to accommodate such additional screens as may be desired. [0031] The device 10 may be made from any material which would be acceptable for use in the sterile conditions required in an operating room. The device may be disposable after use on one patient in which case various plastics may be acceptable. If reuse of the device is required then the material must be capable of resterilization such as by heat, chemical means or other sterilizing techniques.

[0032] The screens can be any material and have openings of any size to meet the desired use. The screens may be stainless steel which is sterilizable. Alternatively, the screens may be disposable even if the housing or canula are reusable. [0033] One of the principal advantages of the present invention, is that material which is suitable for bone grafting may be harvested at any site in the body and not simply at the site selected for bone grafting procedures. Thus, depending upon the amount of bone material required, and various other conditions of the patient, the site for generation of bone graft material may be significantly removed from the selected site at which the grafting procedure is to be performed. In such instances, the surgeon may prepare a site for creation of suitable bone grafting material. That site may be chosen by the surgeon based on whatever factors are most desirable in the case of any particular patient. The surgeon prepares the site and gains access to the bone where chips are to be generated. Then, using the device as described herein, the surgeon commences the collection of the bone chips. The bone material removed from the patient's bone is collected using the apparatus referred to above. The bone material which is then collected on the screen 40 is ready for use in the bone grafting procedure. The collection of material may continue at the same time that bone grafting procedures are carried out at a selected site for bone grafting or the collection may be completed before the bone grafting procedure itself is started. The present invention thus allows for the collection of material suitable for bone grafting so that the surgeon is then in a position to use appropriate bone grafting material for the intended purpose at a selected site. [0034] The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The presently disclosed embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

Claims:

1. A device for harvesting bone fragments comprising; a canula, and a gathering housing,

said gathering housing defining an internal chamber,

said gathering housing including an outlet port and an inlet aperture, said inlet aperture adapted to receive one end of said canula, said chamber including at least one screen located within said chamber so that fluid flowing from said inlet port to said outlet port passes through said at least one screen.

2. The device of claim 1 wherein said chamber includes at least one upstream screen and at least one downstream screen.

3. The device of clam 1 wherein said housing comprises at least one additional passageway extending from said chamber through said housing for admitting fluid into said chamber.

4. The device of claim 1 wherein said housing comprises an upstream cup and a downstream cup.

5. The device of claim 4 wherein said at least one screen is captured between said upstream and downstream cups.

6. The device of claim 5 wherein said chamber includes at least two such screens and said at least two such screens are captured between said cups.

7. The device of claim 6 wherein said downstream cup includes a shut off valve.

8. The device of claim 7 wherein said upstream cup includes a passageway for introducing fluids into said internal chamber.

9. The device of claim 1 wherein said device further includes means for attaching a suction conduit to said outlet port.

10. A method of collecting bone material suitable for bone grafting at a selected site upon generating bone fragments suitable for use in bone grafting, comprising: drawing said bone fragments into a device in accordance with any of claims 1 to 9 and collecting bone fragments drawn into said device on said at least one screen.

11. The method of claim 10 wherein said method includes passing said bone fragments through a relatively coarser screen to remove undesirable material and collecting said bone fragments on a relatively finer screen.

12. The method of claim 11 wherein said generating of bone fragments occurs adjacent said selected site.

13. The method of claim 10 wherein said generating of bone fragments occurs at a site which is remote from said selected site.

14. A method of using the device of any of claims 1 to 9 comprising: collecting bone fragments suitable for use in bone grafting, by drawing said bone fragments into said device and collecting said bone fragments on said at least one screen.