Apparatus and method for cleaning a surgically prepared, concave bone surface

Abstract

An apparatus suitable for cleaning a surgically prepared bony concavity includes a body portion adapted to supply pressurized fluid (preferably carbon dioxide gas) to the concavity and aspirate surface debris. The apparatus further comprises a head having an orifice with a plane, circular rim having a diameter less than that of the bony concavity. A method for cleaning a surgically prepared, concave, generally hemispherical bony cavity includes the steps of: covering a region of the hemispherical bony concavity with a cleaning head; supplying a pressurized fluid to the region covered by the cleaning head, and collecting the pressurized fluid from the covered region with a surface debris aspirator coupled to the cleaning head. A cleaning head having a generally circular orifice substantially seals and encloses a spherical zone to be cleaned.

Description

This application is a continuation-in-part of U.S. application Ser. No. 10/941313 filed on Sep. 15, 2004 (inventors Pratt, et al.) and claims priority to that application as to material disclosed therein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to surgical instruments, and more particularly to apparatus and method for cleaning a surgically prepared working surface.

2. Description of the Related Art

In traditional orthopedic surgery, bone is prepared to receive a prosthetic implant by first cutting or sculpting the bone with a manual or powered tool such as a saw, drill, or broach. Next, the exposed bone is usually cleaned with a sterile saline solution for lavage and irrigation. Finally, suction is applied to remove debris. Often, surgical sponges are inserted into a cavity or against the bone surface to absorb excess fluids.

Joint replacements are commonly but not necessarily secured with the aid of “joint cement” or biocompatible adhesives. A typical such cement is a polymethyl methacrylate. The success of such adhesives is thought to depend in part on proper preparation of the bone bed.

U.S. Pat. No. 5,037,437 to Matsen III (1991) discloses a significant improvement in the art of preparing bone surface for cemented joint replacement surgery. Matsen identified some of the previously unrecognized shortcomings of traditional liquid flushing lavage for preparation of the cancellous portions of an exposed bone bed. Matsen's invention was based on the finding that dry flowing gas directed at and into the sculpted bony bed effectively prepares the bone for prosthetic implantation. When a bone cement is also used, the use of gas increases the likelihood of strong mechanical interdigitation of the bone cement with the bone. A number of such advantages to the gas lavage technique are identified in U.S. Pat. No. 5,037,437; the enumerated advantages need not be repeated here. Additional advantages may exist which have not been identified. Matsen also suggests that carbon dioxide is especially well suited for use as the dry gas for bone lavage, being demonstrated safe for use in the human body. As he notes, “the very high diffusion coefficient of carbon dioxide causes it to present a significantly lower risk of embolism as compared to the use of nitrogen or oxygen.” Moreover, carbon dioxide gas is commonly available in hospital operating rooms, finding use in laparascopic surgery, for example.

Since the publication of the Matsen patent, tools have become available for preparing bony surfaces by sterile, dry gas lavage, or lavage with sterile admixtures of gas and liquid. A carbon dioxide lavage system is available, for example, from Kinamed, Inc. in Camarillo, Calif. (marketed under the trade name “CarboJet”). The use of carbon dioxide is believed to be more effective than liquid debris removal because a compressed gas jet creates strong, fluctuating pressure gradients, displacing debris rapidly and thoroughly. This method is more effective at removing fluid and fluid-suspended debris from the interstices of cancellous bone.

Although surgical gas lavage nozzles are available, typical nozzles must be used in concert with surgical suction tools. Simultaneous manipulation and coordination of both gas supply and suction is difficult. Flow of the gas is not well controlled or confined to the bony surface. Both suction and gas jet must be constantly moved in a drying pattern to effectively clean and dry the bony surface. The difficulty of this technique in increased in surgical situations that permit only limited access or interfere with the surgeon's freedom of motion. As one example, in hip replacement surgery it is usual to prepare the acetabular cup by mechanical reaming or grinding into a generally hemispherical, concave shape, suitable for receiving an acetabular implant component. Before gluing the component into place, it is desirable to treat the acetabular surface by gas lavage. However, efficient, simultaneous suction and drying of a small, concave, generally hemispherical cup presents is awkward with conventional tools. No gas lavage tool is available that is specifically adapted to efficiently clean and dry a concave cup (an acetabular cup, for example).

For these and other reasons, a need persists for specially adapted lavage devices and methods which can better access specific bony surfaces, and which more efficiently and conveniently prepare the surfaces to receive cement or implants. Any time saved in the operating room is of great value (medically and economically) to both surgeon and patient.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, an apparatus suitable for cleaning a concave bony surface includes: a body portion adapted to supply pressurized fluid to the surgically prepared working surface and aspirate debris dislodged from the bony working surface; and a head portion adapted to confine the supplied pressurized fluid to flow substantially across the surgically prepared working surface to dislodge debris therefrom when the head portion is in contact with the bony working surface. The head portion has a generally circular orifice having a diameter less than that of the concave, generally hemispherical recess to be cleaned, thereby allowing the orifice to substantially seal against the inside surface of the hemispherical recess.

According to another aspect of the invention, a method for cleaning a surgically prepared, concave, generally hemispherical bony cavity includes the steps of: covering a region of the hemispherical bony concavity with a cleaning head; supplying a pressurized fluid to the region covered by the cleaning head, and collecting the pressurized fluid from the covered region with a surface debris aspirator coupled to the cleaning head. A cleaning head having a generally circular orifice substantially seals and encloses a spherical zone to be cleaned.

These and other aspects of the invention will become apparent from a review of the accompanying drawings and the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is generally shown by way of reference to the accompanying drawings in which:

FIG. 1 is a side elevation view (with some system elements indicated schematically) of an apparatus and system suitable for cleaning a surgically prepared working surface in accordance with the present invention;

FIG. 2 is a perspective view of the cleaning head of the apparatus of FIG. 1;

FIG. 3 is a plan view from below of the cleaning head of FIG. 2;

FIG. 4 is a sectional view taken along section line 4 in FIG. 3;

FIG. 5 is a sectional view taken along the section line 5 in FIG. 3;

FIG. 6 is a sectional view taken along the section 6 line in FIG. 3;

FIG. 7 is an perspective view of the apparatus of the invention disposed in working relation to a concave bony surface, with the bony body and the apparatus partially cut away to better visualize the relationship between the apparatus and the bone; and

FIG. 8 is a sectional view of the apparatus of the invention in working relation to a concave bony surface, with both the apparatus and bone shown in cross section along the same sectioning plane as that of FIG. 4, also showing presumed fluid flow lines.

DETAILED DESCRIPTION OF THE INVENTION

Some embodiments of the invention will be described in detail with reference to the related drawings of FIGS. 1-8. Additional embodiments, features and/or advantages of the invention will become apparent from the ensuing description or may be learned by practicing the invention. In the figures, the drawings are not to scale with like numerals referring to like features throughout both the drawings and the description.

The following description is not to be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention.

The acetabular cup of the human hip is a concave, generally hemispherical recess in the pelvis. In a hip replacement surgery, this cavity is typically reamed or otherwise mechanically prepared to receive a cup-like acetabular prosthetic component. After hollowing the acetabular cup to the desired shape and dimension, it is desirable to apply a fluid lavage, preferably in the view of the inventors a carbon dioxide gas lavage. Such lavage better prepares the acetabular cup to receive cement and bond effectively with the prosthetic cup component.

FIG. 1 shows the apparatus or tool in accordance with the invention, generally referred to by reference numeral 10. The embodiment of FIG. 1 is particularly well adapted for cleaning a substantially hemispherical, concave bony surface, such as is presented by a surgically prepared acetabular socket. The tool 10 includes a generally disk-like cleaning head 11 having a generally circular orifice 12, situated on the underside of the head and with the opening facing downward. Preferably, the head 11 is mounted on or depends from an elongated extension neck 14. In one embodiment, the neck 14 includes one or more through passages used to supply pressurized fluid and/or to provide an aspiration pathway. Alternatively, pressurized fluid and vacuum for aspiration could be otherwise supplied to the head via hoses or tubes.

Preferably, a rim 15 of the orifice 12 lies upon and defines a plane disposed obliquely or at an angle a to the long axis X of the elongated neck, so that a normal to the plane of the rim is neither parallel to nor perpendicular the long axis or dimension of the neck 14. In an embodiment in which the neck 14 includes fluid channels, hose couplings are provided near the rearward end of the neck: a pressurized gas hose connection 16 and a vacuum hose connection 18 are shown. Optionally, these connections could be integrated into a trigger type control grip (not shown) which facilitates control of the application/disconnection of both gas and suction, via a simple trigger operated valve. However controlled, fluid (preferably carbon dioxide gas or an admixture of same with liquid) is controllably supplied under pressure from pressurized fluid supply 20 to gas connection 16 via a hose 21. Similarly, suction is controllably supplied from vacuum source 22 via hose 24 to the vacuum hose connection 18.

The head 11 is shown in more detail the view of FIG. 2. The orifice 12 is preferably bounded by a planar, generally circular lip or rim 15. In the embodiment shown, the rim forms a substantially circular perimeter around the orifice 12. The orifice 12 opens into a partitioned internal cavity 28 having at least one inner chamber 30 and at least one outer chamber 32. The aforementioned inner and outer chambers are incompletely isolated from each other by at least one internal partition 34.

Further details are more easily seen in FIG. 3 (plan from below) and in the sectional views of FIGS. 4, 5 and 6. At least one hidden, internal gas channel 36 connects the inner chamber 30 to a pressurized fluid supply passage 38, and thus allow the inner chamber to communicate with the pressurized fluid supply 20. In the embodiment shown, the communication occurs via an internal channel contained in the neck 14; in other embodiments, communication could be directly through a pressurized fluid hose coupled to the head. The inner chamber, communicating passages, and pressurized fluid supply together make up a pressurized fluid supply apparatus. Similarly, a vacuum channel 40 (visible in FIGS. 4 and 6) connects the at least one outer chamber 32 to an aspiration connection 18, allowing the one or more outer chambers to communicate with the vacuum source supply 22. The outer chamber or chambers, vacuum channel(s), vacuum connections, and vacuum source together make up an aspirator. The pressurized fluid chamber and supply channel are seen best in FIGS. 4 and 5; the vacuum channels are better seen in FIGS. 4 and 6.

Pressurized fluid (preferably carbon dioxide) is supplied from a channel 36, which in some embodiments is contained within the neck 14. The pressurized fluid flows into the inner chamber 30. In one embodiment as shown, the inner chamber 30 takes the form of a long narrow slot, arranged diametrically across the circular orifice and substantially running through the center of the circle. Other arrangements are possible: for example, the pressurized fluid supply could be through a central, axial bore, while the vacuum chamber could be an annular cylinder, coaxial with the central bore and incompletely separated from the inner chamber by a cylindrical partition.

The inner chamber 30 (slot) is incompletely isolated from the outer, vacuum chamber 32. At least one partition (two shown: 34 and 42) is disposed between inner and outer chambers. At least one of said partitions 42 terminates in a shoulder 46. The extent of the partition 42 is predetermined to maintain a small. predetermined clearance between the shoulder 46 and a working surface (a concave bony surface), defining a relatively narrow slot through which gas can flow from the inner chamber to the outward chamber (thus from pressure toward vacuum). In one embodiment the shoulder 46 is a straight wall, recessed below the plane defined by the circular rim 15. In other embodiments the shoulder 46 could be slightly convex, and may, near center, extend slightly below the plane of the circular rim; in such an embodiment the necessary clearance for fluid flow is provided by the concave curvature of the bony surface to be cleaned. Preferably, the pressurized fluid is constrained to flow across the bony surface to be cleaned, there being no other significant pathways of fluid communication between the pressurized source 20 and the vacuum 22.

It is advantageous that the rim 15 of the orifice 12 is generally adapted to substantially seal against a concave, generally hemispherical bony surface. The circular orifice in accordance with the invention, having a diameter less than that of the hemispherical concavity to be cleaned, is well adapted to seal to the hemispherical, concave surface. A satisfactory seal can be obtained from a variety of positions and orientations within the concave surface; and the tool can be actively repositioned by manipulating the neck 14, for example by revolving the neck within a cone, in pattern similar to the precession of a child's spinning top. Note that for a fixed rim dimension, a seal can be obtained for any size hemispherical concavity, provided that the diameter of the circular rim is less than that of a great circle of the hemispherical concavity.

The sectional view of FIG. 6 shows the at least one outer or vacuum chamber 32 and associated passages. Note that in the embodiment shown the vacuum chamber includes two compartments 32, which communicate through the transverse passage 38. When the pressurized fluid source 20 and vacuum source 22 are actively coupled to the head, the fluid flows from the inner chamber 30, over the shoulders 46, and into the dual chambers 32; thereafter the fluid, along with debris and tissues, are sucked through the outlet tube 17, into the vacuum line 24, and are ultimately collected in the suction source or aspirator chamber 22 (shown in FIG. 1).

The sections of FIGS. 4, 5, and 6 clearly show one arrangement by which the pressurized and vacuum passages may be arranged without interference with one another. Other arrangements are possible.

The figures also illustrate that the tool can suitably be manufactured from two distinct body parts: a lower component 52 and an upper component 54 (visible in FIG. 2) which are mated under pressure from at least one screw 56. In the simple embodiment shown, two such screws pass through bores in the upper component 54 and engage threaded bores in the lower component 52, allowing simple assembly of the two components. The dual components facilitate manufacture because the hidden fluid and suction passages and chambers can be readily machined in the separate components, then the components assembled to enclose hidden passages as shown. The neck 14 can be inserted tightly or otherwise bonded to the head 11. Similarly, outlet tube 17 can be inserted into a hole bored in the upper body component 54.

The entire head 11 can suitably be machined or otherwise formed from a solid such as aluminum or stainless steel, which are capable of enduring repeated autoclaving for sterilization. Alternatively, polymers or other materials could be used. In some embodiments the tool may be disposable, thereby avoiding the need for sterilization by the hospital.

FIGS. 7 (perspective) and 8 (cross-section) show how the tool 10 can be used to prepare the bony surfaces of an acetabular cup to receive an implant component. The figure assumes that the bone is previously prepared to a generally hemispherical, concave surface. The bony concavity 60 is shown partially cut away in FIG. 7 to render the head 11 visible. The head 11 of the tool is placed within the hemispherical concavity 60 of the acetabular cup. It should be apparent that the diameter of the head 11 must be less than that of the hemispherical concavity of the acetabular cup, and preferably is chosen to be substantially less than that of the cup. Thanks to a known property of spherical geometry, the plane, circular rim 15 of the tool is guaranteed to closely fit a hemispherical concavity such a the acetabular cup (the intersection of a plane and a sphere always defines a circle). A close seal is desirable, but some leakage is tolerable. Having the head 11 engaged with the bony surface 60, the surgeon activates the sources of pressurized gas and suction, and moves the tool 10 in a wobbling pattern by both rotating and tilting the neck 14, in a generally conical pattern. By this means, the rim of the tool wanders around a plurality of intersecting circles, to completely clean the bony surface. When the surface is clean (and dry), the surgeon removes the tool and applies the cement in accordance with medical practice.

When the head is actively engaged with the surface to be cleaned, the rim engages and encloses a region of the concave surface. Geometrically speaking, the enclosed region is substantially a spherical “zone” and more specifically a “zone of one base”: a surface formed by two parallel planes cutting a sphere, where one of the planes is a tangent to the sphere. See The Penguin Dictionary of Mathematics, J. Daintich and R. D. Nelson (Penguin, 1989).

Flow lines in FIG. 8 show the presumed direction of gas flow when the device is activated in engagement with a bony surface. The bony surface can be visualized as surface 60, but here is shown cut away, to better visualize the assumed gas flow in the tool. The extent of the rim or other boundary of the orifice defines a boundary surface for the orifice. The figure assumes that the orifice is fully engaged with concave bony surface 60, by placing with slight pressure the rim 15 flush to the concave bony surface. Thus engaged, circular rim 15 in contact with concave bony surface, the cavity and bone surface together define a substantially enclosed volume or chamber having a pressurized gas source 30 inwardly disposed, and a vacuum or suction 32 more outwardly situated in the head, incompletely separated by partition 34. More generally described, the apparatus thus engaged defines a substantially closed volume having on at least one side a bony surface. When actively coupled to the pressurized gas source and the vacuum source, the volume develops a pressure gradient substantially across the bony surface. The fluid is thus constrained to flow substantially across the surgically prepared surface 60. Most preferably, in at least some region the gradient is substantially tangential to the surface to be cleaned. Thus, the fluid is constrained to flow across the surface to be cleaned, at least in some region.

In a preferred embodiment, the at least one partition 34 constricts or pinches the gas flow, visualized by flow arrows 54 in the figure. Flow between the partition 34 and the bony surface is pinched or constricted as the gas passes through the narrow clearance between partition and bone. Thus, across the narrow shoulder 46 of partition 34 the flow has increased velocity and decreased pressure due to “Bernoulli's principle” or “venturi effect”. Applicants find that the lowered pressure and increased velocity in this pinched channel is efficacious to draw debris and liquid (such as blood) from the interstices of a porous bony surface, which effect is observed to occur with unexpected efficiency. The constricted channel defined between the sill of partition 34 and the bone surface should preferably be less than 10 millimeters, more preferably less than 5 mm, and most preferably even less than three millimeters at the narrowest point.

The entire cleaning process occurs within a closed volume defined by the combination of the cavity and bony surface in close fitted relationship. In addition to increasing the cleaning efficiency, the closed system also reduces splattering and controls the aerosolization of biological materials (such as blood, fat and marrow).

The inventors presently believe that the preferred pressurized gas for use in the invention is carbon dioxide (CO₂). Some of the reasons for this conclusion are set forth in the Matsen patent, referenced above in the “Background of the Invention”. However, the invention could be modified to employ other pressurized gases, or an admixture of liquid and gas. In order to take full advantage of the “Bernoulli effect” in passing through the constricted channel, a compressible fluid such as a gas or gas mixture is greatly preferred. In some embodiments, a mixture of compressed gas and incompressible fluid is used. Such mixtures allow the density of the fluid to be varied controllably to improve cleaning efficiency yet control unwanted tissue damage or creation of emboli.

In the preferred embodiment, the pressurized gas is provided from a relatively more central position and the vacuum applied to the relatively more outside or peripheral portion of the cleaning head. This principle can be followed using a slot and chamber geometry as shown in the figures, or a coaxial, annular arrangement as also mentioned above. Specifically, the pressurized fluid could be supplied through an axial, inner cylindrical chamber or passage, and the vacuum could be applied to an outer annular ring or shell, in a generally coaxial, cylindrical geometry. Using the outer portion for vacuum allocates a larger aperture to the aspiration circuit, which prevents clogging from debris and tissue. However, in some embodiments the arrangement could be reversed if desired (applying pressure from the outer region, vacuum through a central camber).

It is very beneficial, in accordance with the invention, that the plane of the circular rim 15 be angled with respect to the elongated neck 14. An angle a of between 30 and 60 degrees is preferred. An angle of substantially 45 degrees is most preferred. In no event should the neck and orifice facing be either a parallel or perpendicular, because this would make access extremely difficult to a hemispherical concavity. In some embodiments, the coupling between the cleaning head and the neck could be made pivotable in one or more directions, to facilitate manipulation of the device into or within a socket. Flexible or articulable fluid channels could be substituted for the fixed passages illustrated in the drawings. The attachment point between the neck and the head could be shifted. Said attachment point could be more or less offset. Bent, flexible, pivotable, jointed, or articulated necks could be employed.

It is greatly preferred that the head 11 have a thickness dimension that is less than its diameter, and preferably less than half of its diameter. This facilitates insertion of the head into the bony concavity and allows manipulation within the concavity. It is also most preferable that the head 11 has width dimensions generally tapering in the direction away from the orifice, to avoid interference from contacting the rim of an acetabular socket.

In one embodiment, an apparatus substantially as described above is sterilized and packaged in a hermetically sealed, disposable package for the convenience of the surgeon. In such an embodiment, the cleaning tool (not including the vacuum and pressurized fluid sources) is preferably manufactured of a disposable material. Alternatively, if not disposable, the device should be capable of withstanding repeated sterilization procedures.

A person skilled in the art would undoubtedly recognize that other components and/or configurations may be utilized in the above-described embodiments. Moreover, all terms should be interpreted in the broadest possible manner consistent with the context. In particular, the terms “comprises” and “comprising” should be interpreted as referring to elements, components, or steps in a non-exclusive manner, indicating that the referenced elements, components, or steps may be present, or utilized, or combined with other elements, components, or steps that are not expressly referenced.

While the invention has been described in detail with regards to several embodiments, it should be appreciated that various modifications and/or variations may be made in the invention without departing from the scope or spirit of the invention. In this regard it is important to note that practicing the invention is not limited to the applications described hereinabove. Many other applications and/or alterations may be utilized provided that such other applications and/or alterations do not depart from the intended purpose of the invention. For example, the head, orifice, and rim may be shaped to fit contours other than planar surfaces. In some embodiments, admixtures of gas and liquid may be used in place of a carbon dioxide gas. Various control valves and pressure regulation apparatus may be added to the cleaning head or to its supply lines. The body may comprise primarily gas and suction lines. The cleaning head may have multiple pressure chambers and/or multiple vacuum chambers; the head could be rotatable; Other such variations could be devised. A skirt can be added to or substituted for the rim around the cleaning orifice. A flexible or conformable skirt could be used.

Also, features illustrated or described as part of one embodiment can be used in another embodiment to provide yet another embodiment such that the features are not limited to the exemplary embodiments described hereinabove. Thus, it is intended that the invention cover all such embodiments and variations as long as such embodiments and variations come within the scope of the appended claims and their equivalents.

Claims

1. A method for cleaning a surgically prepared, concave, generally hemispherical bony concavity, comprising the steps of:

covering a region of said hemispherical bony concavity with a cleaning head;

supplying a pressurized fluid to said region covered by said cleaning head;

collecting said pressurized fluid from said covered region with a surface debris aspirator coupled to said cleaning head.

2. The method of claim 1, wherein the supplied pressurized fluid is carbon dioxide (CO2) gas, said CO2 gas being suitable for use on the surgically prepared working surface.

3. The method of claim 1, wherein said step of covering a portion of said hemispherical

bony concavity comprises: engaging said bony concavity with a substantially circular, plane cleaning orifice of said cleaning head.

4. The method of claim 3 wherein said circular, plane cleaning orifice defines a plane at

an angle between 30 and 60 degrees relative to an elongated neck coupled to said cleaning head.

5. An apparatus suitable for cleaning a concave, surgically prepared working surface, said apparatus comprising:

means for supplying pressurized fluid to the surgically prepared working surface;

at least one surface debris aspirator operatively coupled to said pressurized fluid supply means; and

means for confining the supplied pressurized fluid to flow substantially across a portion of the surgically prepared working surface;

wherein said means for confining the supplied pressurized fluid includes an orifice having a plane, circular rim, capable of engaging a zone of said concave surgically prepared surface.

6. The apparatus of claim 5, wherein the supplied pressurized fluid is carbon dioxide (CO2) gas, said CO2 gas being suitable for use on the surgically prepared working surface.

7. The apparatus of claim 5, wherein said orifice has a diameter less than that of the concave surface.

8. The apparatus of claim 7, wherein said diameter of said orifice is less than that of a human acetabular socket.

9. The apparatus of claim 8 wherein said confining means comprises a cleaning head having a thickness dimension less than its diameter.

10. The apparatus of claim 9, wherein said means for confining comprises an elongated neck and a cleaning head opened by said orifice;

and wherein a plane defined by said plane, circular rim of said orifice defines an angle in the range of 30 to 60 degrees relative to said elongated neck.

11. The apparatus of claim 10 wherein said angle is substantially equal to 45 degrees.

12. The apparatus of claim 9 wherein said cleaning head had a thickness dimension less than half its diameter.

13. An apparatus suitable for cleaning a surgically prepared bony surface of concave, generally hemispherical recess, said apparatus comprising:

a body portion adapted to supply pressurized fluid to the surgically prepared working surface and aspirate surface debris dislodged from the bony working surface; and

a head portion adapted to confine the supplied pressurized fluid to flow substantially across the surgically prepared working surface to dislodge debris therefrom when said head portion is in contact with the bony working surface, said dislodged surface debris being aspirated by said body portion;

wherein said head portion has a generally circular orifice having a diameter less than that of the concave, generally hemispherical recess, thereby allowing said orifice to substantially seal against the inside surface of said concave, generally hemispherical recess.

14. The apparatus of claim 13, wherein the supplied pressurized fluid is carbon dioxide (CO2) gas, said CO2 gas being suitable for use on the surgically prepared working surface.

15. The apparatus of claim 13, wherein the supplied pressurized CO2 gas flows at a rate suitable for cleaning the surgically prepared working surface from debris.

16. The apparatus of claim 13, wherein said head portion is adapted to confine the supplied pressurized fluid to flow over the surgically prepared working surface to dislodge debris therefrom when said head portion is in contact with the surgically prepared working surface, said dislodged surface debris being aspirated by said body portion.

17. The apparatus of claim 16, wherein the supplied pressurized fluid is carbon dioxide (CO2) gas, said CO2 gas being suitable for use on the surgically prepared working surface.

18. The apparatus of claim 17, wherein the supplied pressurized CO2 gas flows at a rate suitable for cleaning the surgically prepared working surface from debris.

19. The apparatus of claim 13, wherein said body portion includes at least one pressurized fluid channel operatively coupled to at least one fluid jet outlet.

20. The apparatus of claim 19, wherein said body portion further includes at least one surface debris aspirator disposed in operational proximity to said at least one fluid jet outlet.

21. The apparatus of claim 13, wherein said head portion includes at least one partial partition between said at least one surface debris aspirator and said at least one fluid jet outlet.

22. The apparatus of claim 21, wherein said surface debris aspirator is disposed peripherally near a circular rim of said orifice, and said at least one fluid jet outlet is disposed generally near the center of the circle defined by the circular orifice, so that fluid flows generally outward, sweeping debris from the surgically prepared working surface.

23. The apparatus of claim 13 wherein said body portion comprises an elongated neck, disposed at an angle to a plane defined by said rim of said circular orifice.

24. The apparatus of claim 23 wherein said angle is in the range from 30 to 60 degrees, inclusive.

25. The apparatus of claim 24 wherein said angle is substantially equal to 45 degrees.

26. The apparatus of claim 13 wherein the diameter of said circular orifice is less than the diameter of a human acetabular socket.

27. The apparatus of claim 13 wherein said head portion has a thickness dimension less than its diameter

28. The apparatus of claim 27 wherein said head portion has a thickness dimension less than half of its diameter.

29. The apparatus of claim 28 wherein said head portion has width dimensions generally tapering in the direction away from the orifice, to avoid interference from contacting the rim of an acetabular socket.

30. The apparatus of claim 29, wherein said body portion further includes at least one surface debris aspirator disposed in operational proximity to said at least one fluid jet outlet.

31. The apparatus of claim 30, wherein said head portion includes a rim configured to substantially follow the surgically prepared working surface and at least one partition between said at least one surface debris aspirator and said at least one fluid jet outlet.

32. The apparatus of claim 31, wherein said at least one partition is sufficiently recessed from said rim to constrain the supplied jet fluid to flow substantially tangentially relative to the surgically prepared working surface when said rim is in contact with the surgically prepared working surface, said constrained tangential fluid flow sweeping debris from the surgically prepared working surface via said at least one surface debris aspirator.

33. An apparatus for cleaning a surgically prepared, concave bone surface, comprising:

a pressurized fluid supply channel;

an aspiration channel;

a cleaning head, including at least one chamber, in communication with said aspiration channel and said fluid supply channel;

said chamber having a generally circular orifice, the circular boundary of said orifice defining a boundary capable of close engagement with a concave bone surface to substantially close said chamber;

said chamber arranged to create an internal pressure gradient between said pressurized fluid supply channel and said aspiration channel, and having a path for fluid flow from said fluid supply channel to said aspiration channel;

wherein said fluid flow path for fluid flow includes at least one region in which flow is constrained to flow across said concave bone surface.

34. The apparatus of claim 33, wherein said fluid flow path comprises at least one slot, whereby said fluid flow is channeled into a sheet of flow.

35. The apparatus of claim 34, wherein said slot is defined between said boundary surface and a partition which incompletely divides said chamber.

36. The apparatus of claim 33 wherein said orifice is bounded by a rim.

37. The apparatus of claim 21, wherein said pressurized fluid supply channel is adapted to supply pressurized carbon dioxide gas.