BONE REDUCTIONAND PLATE FIXATION FORCEPS

Abstract

A bone reduction and plate fixation forceps including a first arm having a proximal part including a handle and a bifurcated distal part in which a first bone engaging jaw and second bone engaging jaw are configured to engage a first surface of a fractured bone on each side of the fracture, and a second arm having a proximal part including a handle and a distal part comprising a third bone engaging jaw configured to engage a second surface of the fractured bone to clamp the bone between the first and second arm. At least one of the first bone engaging jaws and second bone engaging jaws has a proximal to distal bridge shape.

Claims

1-27. (canceled)

28. A bone reduction and plate fixation forceps, comprising: a first arm having a proximal part comprising a handle and a bifurcated distal part having a first fork with a first bone engaging jaw and a second fork with a second bone engaging jaw in which the first bone engaging jaw and second bone engaging jaw are configured to engage a first surface of a fractured bone on each side of the fracture; and a second arm having a proximal part comprising a handle and a distal part comprising a third bone engaging jaw configured to engage a second surface of the fractured bone to clamp the bone between the first and second arm; wherein the second arm is pivotally attached to the first arm by a first joint disposed between the respective handles and the respective bone-engaging jaws of the first and second arms, characterized in that at least one of the first bone engaging jaws and second bone engaging jaws comprises a distal bone engaging jaw part connected to a proximal bone engaging jaw part by a raised bridging jaw part that defines a bone fixation plate receiving recess, and wherein the first bone engaging jaw and second bone engaging jaw are spaced apart by a distance of 4 to 8 cm.

29. A bone reduction and plate fixation forceps according to claim 28, wherein the distal part of the first or second arm includes a joint allowing rotational movement of a distal end of the distal part about an axis of the distal part of the arm.

30. A bone reduction and plate fixation forceps according to claim 28, in which both the first bone engaging jaw and second bone engaging jaw comprises a distal bone engaging jaw part connected to a proximal bone engaging jaw part by a raised bridging jaw part that defines a bone fixation plate receiving recess.

31. A bone reduction and plate fixation forceps according to claim 28, in which distal part of the second arm is bifurcated and comprises a third fork comprising the third bone engaging jaw and a fourth fork comprising a fourth bone engaging jaw, in which the third bone engaging jaw and fourth bone engaging jaw are configured to engage the second surface of the fractured bone on each side of the fracture.

32. A bone reduction and plate fixation forceps according to claim 31, in which the first bone engaging jaw and second bone engaging jaw are laterally spaced apart by a first distance D1 and the third bone engaging jaw and fourth bone engaging jaw are laterally spaced apart by a second distance D2, wherein D1 is at least 50% greater than D2.

33. A bone reduction and plate fixation forceps according to claim 28, in which the first bone engaging jaw and second bone engaging jaw are laterally spaced apart by a first distance D1, in which D1 is from 5-7 cm.

34. A bone reduction and plate fixation forceps according to claim 31, in which the third bone engaging jaw and fourth bone engaging jaw are laterally spaced apart by a second distance D2, in which D2 is from 2-4 cm.

35. A bone reduction and plate fixation forceps according to claim 28, in which the first and/or second bone engaging jaws have an arcuate profile.

36. A bone reduction and plate fixation forceps according to claim 28, in which the distal and proximal bone engaging jaw parts are configured such that in use they are circumferentially spaced apart around the first surface of the bone by about 50-120°.

37. A bone reduction and plate fixation forceps according to claim 28, in which the bone fixation plate receiving recess has a height of 2 to 7 cm.

38. A bone reduction and plate fixation forceps according to claim 28, in which the bone engaging jaws comprise a plurality of teeth; or the bone reduction and plate fixation forceps includes a ratcheting mechanism attached to one of the first and second arms.

39. A bone reduction and plate fixation forceps according to claim 28, wherein the distal part of the first or second arm includes a joint allowing rotational movement of a distal end of the distal part about an axis of the distal part of the arm, in which the rotational joint is disposed on the distal part of the arm just proximally of a point of bifurcation.

40. A bone reduction and plate fixation forceps according to claim 28, wherein the distal part of the first or second arm includes a joint allowing rotational movement of a distal end of the distal part about an axis of the distal part of the arm, in which the rotational joint is configured to limit rotation of the distal end of the distal part of the first or second arms about the axis of the distal part of the arm to 20°-100°.

41. A bone reduction and plate fixation forceps according to claim 28, wherein the distal part of the first or second arm includes a joint allowing rotational movement of a distal end of the distal part about an axis of the distal part of the arm, in which the rotational joint is configured to limit rotation of the distal end of the distal part of the first or second arms about the axis of the distal part of the arm to 50°-100°.

42. A bone reduction and plate fixation forceps according to claim 28, wherein the distal part of the first or second arm includes a joint allowing rotational movement of a distal end of the distal part about an axis of the distal part of the arm, in which the rotational joint is configured to allow detachable engagement of the bifurcated part of the distal part from the forceps.

43. A bone reduction and plate fixation kit comprising: a bone reduction and plate fixation forceps according to claim 28; and a bone fixation plate configured for passage under a bridge shaped bone-engaging jaw of the bone reduction and plate fixation forceps when the jaw is engaged with the fractured bone.

44. A bone reduction and plate fixation kit according to claim 43, in which the bone fixation plate is a dynamic compression plate.

45. A bone reduction and plate fixation kit according to claim 43, in which the bone fixation plate is a transverse fracture bone fixation plate.

46. A bone reduction and plate fixation kit according to claim 43, in which the plate has an inwardly tapered central section intermediate its ends in a longitudinal aspect, wherein the distal bone engaging jaw part and proximal bone engaging jaw part are spaced apart by a distance X, wherein the ends of plate have a width that is equal to or greater than X and the inwardly tapered central section of the plate has a width that is less than X, whereby the plate is required to be tilted upwardly to allow passage of an end of the plate under the bridged shaped bone engaging jaw, whereby the inwardly tapered central section of the plate can fit between the jaw parts when flush against the bone.

47. A bone reduction and plate fixation kit according to claim 46, in which the bone fixation plate at least one end with a width of 14-16 mm and in which the inwardly tapered central section has a width of 11-13 mm.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0069] FIG. 1 illustrates a transverse Type A fracture of the humeral diaphysis.

[0070] FIG. 2 is a side elevational view of a bone reduction and plate fixation forceps according to the invention shown from distal (right hand side) to proximal (left hand side).

[0071] FIG. 3 is a front elevational view (looking in distal to proximal direction) of the bone reduction and plate fixation forceps of FIG. 2 shown attached to a humeral diaphysis with a transverse fracture.

[0072] FIG. 4 is a sectional view taken along the lines IV-IV of FIG. 3 showing one of the bridge-shaped bone-engaging jaws of the first (upper) arm and one of the bone-engaging jaws of the second (lower) arm.

[0073] FIG. 5 is a front elevational view (looking in distal to proximal direction) of the bone reduction and plate fixation forceps of FIG. 2 shown attached to a humeral diaphysis with a transverse fracture, and with a dynamic compression plate fixed to the bone across the fracture while the forceps is clamped to the bone keeping the bone in the anatomically correct reduced position.

[0074] FIG. 6 is the same as FIG. 4 but illustrates the circumferential spacing angle of the distal and proximal jaw parts of the bridge-shaped jaw.

[0075] FIG. 7 is a side elevational view of a bone reduction and plate fixation forceps according to another embodiment of the invention and including a rotational joint on the distal part of the first arm just proximal of the point of bifurcation.

[0076] FIG. 8 is a side elevational view of the bone reduction and plate fixation forceps of FIG. 7 showing a modular jaws detached from the distal part of the first arm.

[0077] FIG. 9 is an elevational view of the bone reduction and plate fixation forceps on FIG. 7 shown showing the rotational movement of the jaws about a longitudinal axis of the distal part of the first arm allowing the jaws to rotate to adapt to a distance gradient across the fracture site.

[0078] FIG. 10 is a perspective view of a bone reduction and plate fixation forceps according to the invention with a modular detachably attachable bifurcated distal end.

[0079] FIG. 11 is a plan view from above of the modular bifurcated distal end with rotational joint.

[0080] FIG. 12 is a side elevational view of the forceps and bifurcated distal end of FIGS. 10 and 11 shown attached to a bone.

[0081] FIG. 13 is a top plan view of a tapered bone fixation plate according to the invention.

[0082] FIG. 14 is a sectional side elevational view of the a jaw forming part of a forceps according to one aspect of the invention in which the distance between the jaw parts is equal to the width of the ends of the plate of FIG. 13 (15 mm) and greater than the width of the inwardly tapered part of the plate (12 mm) and the distance between the jaw part and the bridging part of the jaw (18 mm) is greater than the width of the ends of the plate (15 mm).

[0083] FIG. 15A and FIG. 15B are top plan and end elevational views, respectively, of a conventional bone fixation plate.

[0084] FIGS. 16A and 16B are top plan and end elevational views, respectively, of a plate according to the invention with an inwardly-tapered central section.

[0085] FIG. 17 is a perspective view of a bone reduction and plate fixation forceps according to an alternative embodiment of the invention.

[0086] FIG. 18 is a perspective view of a distal end of the bone reduction and plate fixation forceps of FIG. 17.

[0087] FIG. 19 is a further perspective view of the bone reduction and plate fixation forceps of FIG. 17.

[0088] FIG. 20 is a side elevational view of a distal end of the bone reduction and plate fixation forceps of FIG. 17.

DETAILED DESCRIPTION OF THE INVENTION

[0089] All publications, patents, patent applications and other references mentioned herein are hereby incorporated by reference in their entireties for all purposes as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference and the content thereof recited in full.

Definitions and General Preferences

[0090] Where used herein and unless specifically indicated otherwise, the following terms are intended to have the following meanings in addition to any broader (or narrower) meanings the terms might enjoy in the art:

[0091] Unless otherwise required by context, the use herein of the singular is to be read to include the plural and vice versa. The term “a” or “an” used in relation to an entity is to be read to refer to one or more of that entity. As such, the terms “a” (or “an”), “one or more,” and “at least one” are used interchangeably herein.

[0092] As used herein, the term “comprise,” or variations thereof such as “comprises” or “comprising,” are to be read to indicate the inclusion of any recited integer (e.g. a feature, element, characteristic, property, method/process step or limitation) or group of integers (e.g. features, element, characteristics, properties, method/process steps or limitations) but not the exclusion of any other integer or group of integers. Thus, as used herein the term “comprising” is inclusive or open-ended and does not exclude additional, unrecited integers or method/process steps.

[0093] As used herein, the term “proximal to distal” as applied to the bridge-shaped bone engaging jaw means that the jaw is configured to extend across the bone generally orthogonal to a longitudinal axis of the bone.

[0094] The term “bridge-shaped” as applied to a bone-engaging jaw means that the jaw has distal and proximal bone engaging jaw parts connected by a bridging jaw part that is configured to be spaced from the bone surface when the jaw is engaged with the bone providing a fixation plate receiving recess. Generally, the bridge-shaped jaw is configured such that the distal and proximal jaw parts are spaced apart by at least 2-5 cm, and the bridging jaw part has a height of at least 1-2 cm above the bone surface, to allow passing a fixing plate under the bridge shaped jaw when it is engaged with a bone.

[0095] The term “bifurcated” as applied to the distal part of the first or second arms means that the arm forks into two forks at a forking point. Generally, the forks diverge in a symmetrical manner. Typically, the forks are mirror images of each other. Although the embodiment described herein, show both first and second arms having a bifurcated distal part, it will be appreciated that the distal part of the second arm does not have to bifurcate, and may comprise a single arm with a done engaging jaw configured to span the fracture. Likewise, the invention is not restricted to first and/or second arms that are bifurcated, but may be embodied with an arm having a distal part that forks into three or more arms, depending on the application.

[0096] The term “bone fixation plate” refers to a plate used in orthopaedic surgery to attach to a fractured bone to provide structural support to the bone, keep the bone in an anatomically reduced position, and aid in the healing process. One example of a bone fixation plate is a dynamic compression plate. Generally, bone fixation plates include a number of holes that allow the plate to the fixed to the bone with screws. Often the holes are countersunk holes. The plate may be contoured to the shape of a specific bone. Generally, the plate is monoplanar. Examples of bone fixation plates include dynamic compression plates, locking plates, and combined locking compression-dynamic compression plates.

[0097] The term “handle” refers to formations on the proximal end of each arm, for example finger or palm engaging loop or handle that facilitate a surgeon holding and using the forceps.

[0098] The term “limited rotation” as applied to the rotational joint should be understood to mean that the rotational joint is not free to rotate fully about its axis of rotation but that rotation is limited to rotation about less than 120° or 100°, and generally rotation about 20°-100°, 50°-100° or 60°-80° about its axis of rotation.

[0099] In the context of treatment and effective amounts as defined above, the term subject (which is to be read to include “individual”, “animal”, “patient” or “mammal” where context permits) defines any subject, particularly a mammalian subject, for whom treatment is indicated. Mammalian subjects include, but are not limited to, humans, domestic animals, farm animals, zoo animals, sport animals, pet animals such as dogs, cats, guinea pigs, rabbits, rats, mice, horses, camels, bison, cattle, cows; primates such as apes, monkeys, orangutans, and chimpanzees; canids such as dogs and wolves; felids such as cats, lions, and tigers; equids such as horses, donkeys, and zebras; food animals such as cows, pigs, and sheep; ungulates such as deer and giraffes; and rodents such as mice, rats, hamsters and guinea pigs. In preferred embodiments, the subject is a human. As used herein, the term “equine” refers to mammals of the family Equidae, which includes horses, donkeys, asses, kiang and zebra.

Exemplification

[0100] The invention will now be described with reference to specific Examples. These are merely exemplary and for illustrative purposes only: they are not intended to be limiting in any way to the scope of the monopoly claimed or to the invention described. These examples constitute the best mode currently contemplated for practicing the invention.

[0101] Referring to the drawings, and initially to FIGS. 2 and 3, a bone reduction and plate fixation forceps is described, indicated generally by the reference numeral 1. The forceps comprises a first arm 2, second arm 3, and a pivot joint 4 providing pivoting scissors-like articulation of the arms.

[0102] The first arm 2 has a proximal section 5 with a handle 6A and a bifurcated distal end 7 with diverging forks 8A, 8B each terminated in a bone engaging jaw 9A, 9B. In use, the jaws 9A, 9B are used to grasp a first surface 14 of a fractured bone on each side of a fracture (as illustrated in FIG. 3). In the embodiment shown, the jaws 9A, 9B are laterally spaced apart by about 6 cm, although it will be appreciated that the spacing may be varied according to the bone being treated and the type of fracture.

[0103] The second arm 3 has a proximal section 10 with a handle 6B and a bifurcated distal end 11 with diverging forks 12A, 12B each terminated in a bone engaging jaw 13A, 13B. In use, the jaws 13A, 13B are used to grasp a second surface 18 of a fractured bone on each side of a fracture 19 (as illustrated in FIG. 3). In the embodiment shown, the jaws 13A, 13B are laterally spaced apart by about 3 cm, although it will be appreciated that the spacing may be varied according to the bone being treated and the type of fracture.

[0104] The pivot joint 4 is a conventional pivot joint used in orthopaedic forceps and will not be described in more detail.

[0105] The forceps 1 also includes a ratcheting mechanism comprising counter-facing ratcheting racks 15A, 15B to lock the two arms, relative to each other, and, thereby, maintain a force between the jaws of each arm to hold the bone fragments together after the forceps have been released from a surgeon's hand. Elastic deformation of the arms generally provides the force.

[0106] Referring to FIGS. 4 to 5, the bone engaging jaws 9A, 9B of the first arm 2 are described in more detail. As illustrated best in the sectional view of FIG. 4, the jaws have a distal to proximal (right to left in FIG. 4) bridge shape configured to grip the bone at spaced apart points across the first surface providing a recess 16 to receive a bone fixation plate when the jaws are engaged with the bone. The bridge shaped jaw comprises a distal jaw part 17A, a proximal jaw part 17B and an arcuate bridging jaw part 17C that define (along with the first surface of the bone during use) the plate-receiving recess 16. In the embodiment shown, the bridge-shaped jaw is configured such that during use the distal and proximal jaw parts are circumferentially spaced around the top surface at an angle O of about 80° as shown in FIG. 4. In the embodiment shown, the recess has a height of about 1 cm.

[0107] A dynamic compression bone fixation plate 20 is shown in FIGS. 4 to 6, which has been placed in position after the bone fragments have been reduced and fixed in a reduced position with the forceps 1, and then screwed to the bone across the fracture with screws 21. Although not illustrated, the recesses 16 may be dimensioned to allow passage of the fixing plate 20 under the bridging jaws in a tight but sliding manner, which will facilitate the bridge-shaped jaws maintain the plate in position while it is being screwed to the bone across the fracture. The plate 20 may also be contoured to fit in the recess and conform to the contours of the top surface of the bone.

[0108] The bone engaging surfaces of the jaws comprises a series of serrated teeth 22 to facilitate the forceps grasping the bone.

[0109] In use, the forceps of the invention may be used to hold a fractured bone in a reduced position while fixing a bone fixation plate to a first surface of the bone across the fracture. The process includes the steps of the surgeon (at least partly) reducing the bone fragments to an anatomically correct position, and holding the bone fragments in the at least partly reduced configuration using the bone reduction and plate fixation forceps as described above. As illustrated in FIG. 3, this leaves the first surface 14 of the bone on each side of the fracture exposed. The bone fixation plate 1 (a dynamic compression plate) is then passed along the first surface of the bone under the jaws 9A, 9B until the plate is positioned over a section of the first surface of the bone on each side of the fracture, as illustrated in FIG. 5. The surgeon can then fix the bone fixation plate to the bone while the bone reduction and plate fixation forceps holds the bone fragments in the reduced configuration. Fixing comprises drilling holes in the bone through holes in the plate, and then fixing the plate to the bone with screws 21. The holes in the plate may be countersunk holes. Once the plate has been screwed to the bone, the surgeon then releases and removes the forceps.

[0110] In some embodiment, the method may involve partly reducing the bone fragments; holding the bone fragments in the partly reduced configuration using a bone reduction and plate fixation forceps 1, further reducing the bone fragments while the bone fragments are held in place with the bone reduction and plate fixation forceps, and then adjusting the bone reduction and plate fixation forceps to fix the bone fragments in a fully reduced position.

[0111] Referring to FIGS. 7 to 9, an alternative embodiment of the forceps of the invention is illustrated, indicated generally by the reference numeral 30, in which parts described with reference to the previous embodiment are assigned the same reference numerals. In this embodiment, the bifurcated distal end 7 of the first arm 2 has a proximal shaft 31 and a bifurcated part including the forks 8A, 8B connected by a joint 32. The joint is a rotational joint, that allows the bifurcated part (e.g. forks 8A, 8B and jaws 9A, 9B pivot about a longitudinal axis of the shaft 31 allowing positional adjustment of the jaws to account for bones having a different diameter on opposite sides of a fracture site. FIG. 9 illustrates the positional adjustment of the jaws relative to a bone. The rotational joint may be any type of joint that allows this “see-saw” pivotal movement of the jaws relative to the forceps.

[0112] Referring to FIG. 8, the joint 32 may be configured to allow detachable engagement of the bifurcated part and may include a male part 33 on the bifurcated part configured for detachable engagement with a female part 34 on the shaft 31 (or vica-versa). In use, the rotational joint allows positional adjustment of the jaws when the jaws are applied to a bone to account for bones having a different diameter on opposite sides of a fracture site. In this embodiment, the jaw (or jaws) of the second arm are not rotationally adjustable and act as an anchor for the forceps on the bone.

[0113] FIGS. 10-12 are further illustrations of the detachable bifurcated part having a rotational hinge joint comprising a male part 33 on the bifurcated part configured for detachable engagement with a female part 34 on the shaft 31.

[0114] FIG. 13 illustrates a bone fixation plate according to the invention indicated generally by the reference numeral 40. The plate is an elongated plate with a superior surface 41 and an anterior surface (not shown) with ends 42 and an inwardly-tapering central section 43 disposed between the ends. The ends of the plate have a width of about 15 mm and the inwardly tapered section has a width at its narrowest section of about 12 mm. The inwardly tapered section extends along about one half of the length of the plate and has a maximum width of 14 mm along at least one third of the length of the plate.

[0115] FIG. 14 illustrates a jaw of a forceps according to an alternative embodiment of the invention, indicated generally by the reference numeral 50. Forceps including this type of jaw are configured for use with the tapered plate of FIG. 13. The jaw 50 has a distal jaw part 51 and proximal jaw part 52 separated by a distance of 15 mm as illustrated. The bridging part 53 of the jaw is higher than jaws described previously and has a dimension between the jaw part 51 and a side 54 of the bridging part 53 of 18 mm. In this way, the plate 40 cannot be passed under the jaw while it is flush to the plate, and has to be tilted upwardly to fit. Once the leading end 42 of the plate 40 has passed under both jaws and the jaws are aligned with the inwardly tapered central section 43 of the plate 40, the plate can be lowered to abut the plate where the inwardly tapered section fits between the jaw parts 51 and 52. This embodiment allows the ends of the plate to be wider than otherwise allowed by the jaw configuration, allowing more secure fitting of the ends of the plate to the bone.

[0116] FIGS. 15 and 16 show a conventional plate 20 and a tapered plate 40 according to the invention.

[0117] The forceps of the invention may be employed to hold bone fragments in a reduced position while a bone fixation plate is fixed to the bone. It is particularly applicable for use with transverse fractures of long bones, for example the humerus, femur, radius, ulna, metacarpals and metatarsals. It is also particularly applicable for fractures in the diaphysis of long bones.

[0118] The embodiments illustrated show a 4-point forceps (each arm is bifurcated and bears two bone-engaging jaws). However, it will be appreciated that the second arm does not have to be bifurcated and may bear a single elongated bone-engaging jaw configured to engage a bone across the fracture (i.e. a 3-point forceps). Moreover, it will be appreciated that the first arm may includes one, two or more bridge-shaped jaws. At least two bridge-shaped jaws is preferable.

[0119] FIGS. 17 to 20 illustrate a further embodiment of a bone reduction and plate fixation forceps is described, indicated generally by the reference numeral 60, in which parts described with reference to the previous embodiments are assigned the same reference numerals. The forceps comprises a first arm 2, second arm 3, and a pivot joint 4 providing pivoting scissors-like articulation of the arms. The pivot joint 4 is a conventional pivot joint used in orthopaedic forceps and will not be described in more detail.

[0120] The first arm 2 has a proximal section 5 with a handle 6A and a bifurcated distal end 7 with diverging fork parts 8A, 8B each terminated in an n-shaped bone engaging jaw 9A, 9B. As shown in FIG. 17, the fork parts 8A, 8B diverge at a right angle to an axis of the proximal section of the first arm. In use, the jaws 9A, 9B are used to grasp a first surface 14 of a fractured bone on each side of a fracture (as illustrated in FIG. 3). In the embodiment shown, the jaws 9A, 9B are laterally spaced apart by about 6 cm, although it will be appreciated that the spacing may be varied according to the bone being treated and the type of fracture.

[0121] The second arm 3 has a proximal section 10 with a handle 6B and a bifurcated distal end 11 with diverging forks parts 12A, 12B each terminated in a bone engaging jaw 13A, 13B. As shown in FIGS. 17 and 18, the fork parts 12A, 12B diverge at a right angle to an axis of the proximal section of the second arm. The distal end 11 comprises a rotational joint 61 allowing the bifurcated distal end 11 a degree of rotation about an axis of the second arm 3. In use, the jaws 13A, 13B are used to grasp a second surface 18 of a fractured bone on each side of a fracture 19 (as illustrated in FIG. 3). In the embodiment shown, the jaws 13A, 13B are laterally spaced apart by about 3 cm, although it will be appreciated that the spacing may be varied according to the bone being treated and the type of fracture.

[0122] Referring to FIGS. 4 to 5, the bone engaging jaws 9A, 9B of the first arm 2 are described in more detail. As illustrated best in the sectional view of FIG. 4, the jaws have a distal to proximal (right to left in FIG. 4) bridge shape configured to grip the bone at spaced apart points across the first surface providing a recess 16 to receive a bone fixation plate when the jaws are engaged with the bone. The bridge shaped jaw comprises a distal jaw part 17A, a proximal jaw part 17B and an arcuate bridging jaw part 17C that define (along with the first surface of the bone during use) the plate-receiving recess 16. In the embodiment shown, the bridge-shaped jaw is configured such that during use the distal and proximal jaw parts are circumferentially spaced around the top surface at an angle θ of about 80° as shown in FIG. 4. In the embodiment shown, the recess has a height of about 4 cm.

EQUIVALENTS

[0123] The foregoing description details presently preferred embodiments of the present invention. Numerous modifications and variations in practice thereof are expected to occur to those skilled in the art upon consideration of these descriptions. Those modifications and variations are intended to be encompassed within the claims appended hereto.