FIELD OF THE INVENTION
The present invention relates to surgical saw blades and, more particularly, to a surgical saw blade that efficiently cuts a slot into the bone against which the blade is applied.
BACKGROUND OF THE INVENTION
In a surgical procedure, it is sometimes necessary to use a saw to remove tissue, including bone and cartilage. Often a powered saw is used to perform this procedure. A saw blade is attached to the saw. A drive assembly internal to the saw reciprocates the blade in a back and forth motion. This type of blade is provided with teeth that extend outwardly from a side edge of the blade body.
FIG. 1 illustrates a surgical saw blade 150 and the cut created by the blade as is known in the prior art. As shown in FIG. 1, a wall of bone remains between the two cuts created by the blade of the prior art. The surgeon must remove the wall of bone using another instrument to create the desired slot.
SUMMARY OF THE INVENTION
The reciprocating saw blade of this invention is designed with two walls set apart from each other with blade teeth arranged on each wall in a pattern along the distal end of each wall and on the inner surface of each wall. An advantage of the patterned relationship of the blade teeth of this invention is that, during a single cutting motion, the distal teeth provide the initial cut and the inner teeth remove additional material along the pathway. This increases the amount of material removed in one cut, leaving a small amount of material (bone) at the bottom of the slot for the surgeon to remove in the final step. Thus, the blade configuration and the tooth pattern of the saw blade of this invention improves the cutting efficiency.
These and other features and advantages of the invention will be more apparent from the following detailed description that is provided in connection with the accompanying drawings and illustrated exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a view of a prior art saw blade and the cut it makes;
FIG. 2 is a view of the saw blade of the present invention and the cut it makes;
FIG. 3A illustrates a perspective view of a saw blade assembly of the present invention with the saw blade of FIG. 2;
FIG. 3B illustrates a top view of the saw blade of FIG. 3A;
FIG. 3C illustrates a side view of the saw blade of FIG. 3A;
FIGS. 4A and 4B illustrate perspective views of the base of the saw blade of FIG. 2;
FIG. 4C illustrates a bottom view of the saw blade of FIG. 2;
FIG. 4D illustrates a side view of the saw blade of FIG. 2;
FIG. 4E illustrates a top view of the saw blade of FIG. 2;
FIGS. 5A-C illustrate perspective, front and side views of the keel portion (side wall) of the saw blade of FIG. 2;
FIG. 5D is an enlarged view of a tooth of the keel portion of FIGS. 5A-C;
FIGS. 6A-C illustrate perspective, front and side views of the opposing keel portion (opposing side wall) of the saw blade of FIG. 2;
FIG. 6D is an enlarged view of a tooth of the opposing keel portion of FIGS. 5A-C;
FIG. 7 illustrates an alternate embodiment of a side wall of the present invention (with multiple rows of teeth);
FIG. 8A illustrates a side view of another side wall of the present invention (with overlapping teeth for improved cutting efficiency);
FIG. 8B illustrates a front view of the side wall of FIG. 8A; and
FIG. 9 illustrates a side view of another embodiment of a saw blade of the present invention (with a third blade positioned between first and second blades, so their kerfs overlap).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention provides a reciprocating saw blade which is designed with two walls set apart from each other with blade teeth arranged on each wall in a pattern along the distal end of each wall and on the inner surface of each wall. An advantage of the patterned relationship of the blade teeth of this invention is that, during a single cutting motion, the distal teeth provide the initial cut and the inner teeth remove additional material along the pathway. This increases the amount of material removed in one cut, leaving a small amount of material (bone) at the bottom of the slot for the surgeon to remove in the final step. Thus, the blade configuration and the tooth pattern of the saw blade of this invention improves the cutting efficiency.
Referring now to the drawings, where like elements are designated by like reference numerals, FIG. 2 illustrates a surgical saw blade 100 constructed in accordance with the present invention. As shown in FIG. 2, saw blade 100 creates a slot 200 with minimal excess bone needing to be removed by the surgeon. Saw blade 100 has a base 20, a pair of opposing sidewalls 40a, 40b, a shaft 28 and a spacer 30. Teeth 46a, 46b extend from the distal end of the opposing sidewalls 40a, 40b and teeth 44a, 44b project from the inner surface of the sidewalls 40a, 40b. Saw blade 100 may be formed of material such as stainless steel and/or carbide. In an alternate embodiment, and as detailed below, there may be a third sidewall 40c with teeth inserted between the opposing sidewalls, 40a, 40b so the kerfs overlap.
Reference is now made to FIG. 3A which illustrates a saw blade assembly 101 that includes the saw blade 100 with a base 20 having a generally oblong shape with a proximal end 24 and a distal end 26 (FIGS. 3B and 3C). A shaft 28 extends from the proximal end of the base 20. Shaft 28 has a proximal end 27 and a distal end 29. Proximal end 27 is configured to connect to a drive assembly 110 of the saw (shown schematically in FIG. 3A). Proximal end 27 may have any configuration as is known in the art for connecting to a drive assembly.
As shown in FIGS. 4A-E, base 20 has a top surface 23 and a bottom surface 25. A spacer 30 is formed on the bottom surface 25 of the base. The spacer 30 is sized to reflect the desired width of the cut to be made by the saw blade 100. Additionally, the spacer 30 acts as a stop for determining the depth of the cut. A pair of side walls 40a, 40b extends from the bottom surface 25 of the base 20. Each side wall 40a, 40b has a center 41a, 41b, a periphery 49a, 49b, and two opposing side surfaces, for example, an inner surface 42a, 42b and an opposing outer surface 43a, 43b).
FIG. 5A illustrates the side wall 40a with a keel shape (having a keel-shape configuration), center 41a, periphery 49a, inner surface 42a and opposing outer surface 43a. The side wall includes teeth 46a on the distal end, on the periphery 49a. Additionally, teeth 44a are arranged on the inner surface 42a of the side wall 40a. The teeth 44a on the inner surface of the side wall 40a are partially cut out and bent inward. The teeth 44a may be arranged in a pattern on the sidewall 40a. Teeth 44a are preferably disposed in a row about parallel to the row formed by teeth 46a. Teeth 44a are spaced from teeth 46a by a distance “D” (FIG. 5B) representing the distance between teeth in the rows (i.e., the distance between the tooth support 45 of one of the teeth 44a and the tooth support 47 of the corresponding tooth from teeth 46a). The opposing side wall 40b illustrated in FIGS. 6A-C, may have teeth 44b arranged in a similar pattern, or in a different pattern on the sidewall 40b.
Referring to FIGS. 5A-C, the arrangement of the teeth 46a along the distal end of the sidewall 40a is now described. Each tooth 46a in the illustrated version of the invention is in the form of a triangle. Each tooth 46a is formed to have a most distal end tip (a point) and an opposite tooth support. End tips of teeth 46a extend away from the most distal end of the sidewall 40a. The teeth 46a may be alternating such that every other one is bent at an angle towards the inner surface 42a of the sidewall. This is referred to as the kerf, the spacing between the teeth provides for cutting and removing of bone debris. In an exemplary embodiment the angle is approximately 15 degrees and may range from about 0 to about 20 degrees. There may be several teeth arranged along the distal end of the sidewall 40a. In a preferred embodiment there are seven teeth.
Also shown in the embodiment illustrated in FIGS. 5A-C, teeth 44a are triangular in shape and are partially cut out of the side wall 40a. Each tooth 44a is formed to have a most distal end tip (a point) and an opposite tooth support. In other embodiments, teeth 44a may have any shape such as round, half round, or rectangular. The teeth 44a are bent outward from the sidewall at an angle of approximately 36 degrees and may range from about 0 to about 40 degrees. The number of teeth 44a may vary from 2 to 10. The teeth may be arranged in a pattern similar to the arrangement of the teeth 46a at the distal end of the sidewall (i.e., in a row (or multiple rows) about parallel to the row of distal teeth 46a) or in a completely different pattern. In an exemplary embodiment only, the teeth 44a are positioned in a row (or multiple rows) about parallel to the row of distal teeth 46a. However, other teeth patterns shown in FIGS. 7A-B may include multiple rows of teeth on the inner surface or a V-shape pattern where the teeth are overlapping to improve efficiency of bone removal. In a preferred embodiment, the teeth 44a are arranged as close to the base of the teeth 46a as possible to provide for the cleanest cut (but with teeth 44a still extending radially closer to the center 41a of the keel or side wall 40a than teeth 46a).
Referring to FIGS. 6A-C, the arrangement of the teeth 46b along the distal end of the opposing sidewall 40b is now described. Each tooth 46b is formed in a triangle shape having a point at the most distal end tip and a tooth support (opposite to the end point tip). The teeth may be alternating such that every other one is bent at an angle towards the inner surface 42b of the sidewall 40b. In an exemplary embodiment, the angle is approximately 15 degrees and may range from about 0 to about 20 degrees. There may be several teeth arranged along the distal end of the sidewall 40b. In a preferred embodiment there are eight teeth.
The teeth 46a, 46b are arranged so that, on each sidewall, each tooth tip lies on the same curve. Although every other tooth is angled inward, each tip remains on the same curve. The inward angle provides for more aggressive removal of bone between the cuts created by the teeth 46a, 46b on the distal end of the two sidewalls. Teeth 44a, 44b extend radially closer to the center 41a, 41b of the keel or side wall 40a, 40b than teeth 46a, 46b. A section of bone remains between the two cuts created by the distal teeth 46a, 46b, which is removed by the teeth 44a, 44b on the inner surface 42a, 42b of the sidewall 40a, 40b to create a clean slot 200 that requires only minimal additional bone removal at the bottom of the slot by the surgeon.
In an alternate embodiment illustrated in FIG. 7, side wall 140 may have multiple rows of teeth 144a, 144b arranged below the distal teeth 146 in varying numbers. The exemplary embodiment shown in FIG. 7 illustrates rows of teeth 144a, 144b about parallel to each other and parallel to the distal teeth 146 but the invention contemplates any numbers of rows of teeth 144 (such as rows 144a, 144b, etc) that are parallel or non-parallel to each other and/or to the distal teeth 146.
Another embodiment of the side wall 240 is shown in FIGS. 8A and 8B. Side wall 240 has overlapping teeth 244 arranged below the distal teeth 246. The pattern is like a V (with a “V”-shaped configuration) such that the teeth on the opposing sides of the V create an overlap when they cut.
In a further embodiment of saw blade 300 of the present invention illustrated in FIG. 9, a third side wall 340c is added to the blade assembly, i.e., a third side wall 340c is positioned between first and second blades 340a, 340b so that their kerfs overlap. The third side wall 340c has distal teeth 346c and teeth 344c arranged on both sides of the surface of the side wall. In this embodiment, the kerfs created by each side wall overlap.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. Therefore, the present invention is to be limited not by the specific disclosure herein, but only by the appended claims.
Patent Application
20110230887
