Method and apparatus for collecting bone tissue fragments

[0002] This application is a continuation of U.S. Ser. No. 08/819,403 filed Mar. 17, 1997 now U.S. Pat. No. 6,083,175, which is a continuation of PCT/SE95/01065 filed on Sep. 20, 1995.

[0003] The invention relates to an apparatus for collecting bone tissue fragments from liquids recovered during surgical operations, as well as to a method of collecting bone tissue fragments.

[0004] Many surgical operations are carried out in bone tissue. An example includes those operations conducted within the oral cavity for the purpose of fixing dental problems such as crowns, bridges and prosthesis in toothless regions of the jaw. These operations can include drilling holes in the jaw bone to secure titanium screws that are used as anchoring elements. The bone tissue fragments generated during drilling can be used for filling bone cavities within the jaw that were caused by proceeding pathological processes.

[0005] An aspirator can be used to remove blood from the operative site. The bone tissue fragments created during the operation (such as drilling) are entrained within the liquid flow and will be lost if they are not separated from the liquid flow and collected. Accordingly, a need remains for a simple way for collecting bone tissue fragments.

[0006] Accordingly, the invention is found in a method for collecting bone tissue fragments from liquid evacuated during a surgical operation within bone tissue. The liquid evacuated by suction is passed into a cylindrical sieve through an open end. The liquid passes through the sieve wall from an inside surface to an outside surface. An end wall which is displaceably disposed it the opposite end of the sieve is then moved axially through the cylindrical sieve so that bone tissue fragments collected on the inside surface of the sieve are scraped off from the inner surface and are deposited outside the sieve from the open end of the sieve.

[0007] The invention is also found in a device for collecting bone tissue fragments during surgical operations within bone tissue. The device is cylindrical, with an inlet at one end and an outlet at the other end. The cylindrical device is connected to a suction conduit and there is a cylindrical sieve provided within the device. A space is provided between the outer curved surface of the sieve and the inner curved surface of the cylinder. An open end of the sieve communicates with the inlet of the cylinder and the space communicates with the outlet of the cylinder. The other end of the sieve has an end wall that can be displaced axially through the sieve as a piston.

[0008] FIG. 1 is an axial cross-sectional view of a device for evacuating liquid by suction and removing bone fragments from the liquid according to the invention.

[0009] FIG. 2 is a view of the device of FIG. 1, shown in use.

[0010] FIG. 3 is an end view of the axially displaceable end wall in the sieve.

[0011] FIG. 4 is a cross-sectional view along line 4—4 of FIG. 1.

[0012] The device according to the invention comprises a cylinder 10 open at each end.

[0013] A cover 11 is pushed onto the cylinder 10 at each open end, forming a connection piece 12 and being sealed against the outside surface of the cylinder 10 with an O-ring 13. An aspirator nozzle 14 (seen in fragmentary detail only) is connected to one of the connection pieces (being the left one in FIG. 1). A suction hose 15 is connected to the other connection piece (the right side in FIG. 1) and is also connected to an aspirator (not shown). The left connection piece and aspirator nozzle 14 form an inlet of the cylinder 10 while the right connection piece and suction hose 15 form an outlet of the cylinder 10.

[0014] A cage comprising three straight bars 16 that extend in parallel and are equally spaced circumferentially and two rings 17 and 18 that are integral with and interconnect the straight bars, fits detachably in the cylinder 10. The cage receives a cylindrical sieve 19. The cage serves to keep the outside curved surface of the sieve 19 spaced apart from the inside curved surface of the cylinder 10. As a result, the axially extending spaces 20 (as seen in FIG. 4) are maintained. These spaces 20 are separated from the inlet of the cylinder 10 via ring 18, but communicate with the outlet of the cylinder 10 through an annular plug 21 that is fixed in the cylinder 10.

[0015] At the end of the sieve adjacent the outlet of the cylinder 10, an end wall 22 is provided that has a thicker portion that fits against the inside surface of the sieve 19 and a narrower portion that forms a hollow stud 23 that fits displaceably in ring 17 when the wall is in the end position as shown in FIG. 1. End wall 22 is axially displaceable along the inside surface of the sieve 19. In the embodiment shown, the end wall 22 is perforated. If the end wall 22 is perforated, it is preferable that the apertures within end wall 22 be smaller than the apertures of sieve 19. Perforations in end wall 22 are not necessary, however. Preferably, the device shown in FIG. 1 is made entirely of plastic and is disposable.

[0016] During use. the device is preferably connected in a suction conduit between the aspirator nozzle 14 and the suction hose 15. Low pressure or vacuum is maintained within the suction conduit. If used while drilling occurs in the jaw bone, rinse fluid and blood will be sucked into the sieve 19 via the inlet of the cylinder 10 and will pass through the wall of the sieve 19 into spaces 20 and will then continue to the outlet. Some flow will pass directly to the outlet through perforated end wall 22. The low pressure or vacuum will hold the end wall in the position seen in the Figures as the thicker portion can not pass through ring 17. If the liquid contains coagulated blood or bone tissue fragments, the perforations within end wall 22 will quickly become clogged and the solid particles within the liquid will accumulate on the inside surface of the sieve 19 However, the perforations within end wall 22 provide for a direct continuous flow as long as there are no solid particles to recover.

[0017] In order to recover the material collected in the sieve 19, cylinder 10 is disconnected from end pieces or hoods 11 and is placed within the cylinder 24 of an ordinary syringe as seen in FIG. 2. A piston rod 25 is then connected to the end wall 22 by inserting the piston rod 25 into stud 23. The end wall 22 is then displaced by moving the piston rod 25 axially through the cylindrical sieve 19, thereby scraping the collected material off from the inside surface of the sieve wall. The material is deposited through connection piece 26 of the cylinder, where the connection piece 26 can be constructed as a Luer connection for connecting a suitable mouth piece to the syringe cylinder.

[0018] However, it is not necessary to move cylinder 10 to a syringe for deposition. Instead, it is possible to connect the piston rod to the end wall through the right connection piece 12 (as seen in FIG. 1) and to deposit the material through the left connection piece 12 (of FIG. 1). It may be easier or more comfortable, however, to use a syringe for deposition.