Patent Application
20230190327
The presently disclosed subject matter relates generally to medical devices. Particularly, the presently disclosed subject matter relates to medical cutting devices with a static casing and a blade working body of greater width and related methods.
Traditional surgical saws, such as oscillating saws and reciprocating saws, allow users to cut bones (i.e. perform osteotomies) of relatively large diameters, such as the tibia and femur. These types of surgical saws, however, which are similar in many ways to the toothed saws used to cut wood, metal, and plastic, have significant disadvantages with respect to a patient’s well-being. Because surgical saws utilize rapid motion of the saw blade to cut biological tissues, such as bone and cartilage, a significant amount of heat is generated along the blade and particularly at the blade and bone interface. This can be harmful to the patient since prolonged exposure of bone cells to temperatures at or in excess of 47° C. leads to necrosis of those osteocytes. Another disadvantage of these oscillating and reciprocating bone saws is that they produce uneven cuts, preventing ideal realignment and reduction of the osteotomy gap, which is detrimental to efficient healing of the bone. Oscillating bone saws, which utilize a number of sharpened teeth along their cutting edges, can tear neighboring soft tissues that are inadvertently caught in the serrations of the rapidly moving blade. Tearing of these soft tissues leads to significant blood loss and potential nerve damage, which undoubtedly hampers the health of the patient.
Traditional oscillating, sideways-moving, and reciprocating bone saws have employed a variety of different measures to address these disadvantages. With respect to the generation of excessive heat, these surgical saws can utilize irrigation systems to flush the surgical site near the blade and bone interface. These irrigation systems can be separate, requiring an additional device at the surgical site, or integrated. Although effective at flushing a surgical site of unwanted sources of added friction, these irrigation systems are relatively ineffective at actually cooling the blade at the blade and bone interface. For example, one design for a surgical saw that incorporates a means for irrigation comprises a channel between otherwise parallel portions of a saw blade through which fluid can flow out into the surgical site (See U.S. Pat. No. 5,087,261). This channel, though, can be easily compacted with surgical debris, rendering the integrated irrigation system unusable. In addition, providing a channel between parallel portions of the saw blade necessarily increases the likelihood of a wider, more uneven cut. Other designs for an oscillating bone saw include outlets along the blade’s edge to facilitate irrigation along the blade and bone interface (See U.S. Pat. Nos. 4,008,720 and 5,122,142). However, these channels can be similarly compacted with surgical debris, rendering them useless. More so, channels along the very blade edge result in a blade edge that is not continuous, which reduces the cutting efficiency of the blade. Despite any potential efficacy in flushing a site of surgical debris, these systems do very little to actually cool the very blade edge, specifically at the blade and bone interface. Additionally, having copious amounts of irrigation fluid in the surgical site can hamper the surgeon’s ability to visualize important anatomic structures.
Just as with saws used to cut wood, metal, and plastic, a user can avoid rough or uneven cuts by using a saw blade that incorporates more teeth along the edge of the blade and/or teeth having differing angles. While this can produce a relatively finer cut, the resulting cut still leaves much to be desired in terms of producing smooth, even bone surfaces. Cutting guides, which help to stabilize the blade and keep it on a prescribed plane, are often utilized during an osteotomy to improve the precision of the cut. Still, the improvement is not substantial enough to consider these measures a long-term solution with respect to producing smooth bone cuts. In fact, adding teeth or guiding the blade edge have little effect in preventing inadvertent tearing of neighboring soft tissues. Although efforts are taken to protect soft tissues from damage and prevent significant blood loss, the inherently close confines typical in performing any osteotomy make it extremely difficult to completely eliminate such damage, especially to those tissues that are unseen or positioned beneath the bone being cut. This is compounded by the fact that the saw blades used with many oscillating and reciprocating bone saws are relatively large.
A variety of ultrasonic surgical devices are now utilized in a number of surgical procedures, including surgical blades that are capable of cutting biological tissues such as bone and cartilage. These types of saw blades are powered by high-frequency and high-amplitude sound waves, consequent vibrational energy being concentrated at the blade’s edge by way of an ultrasonic horn. Being powered by sound waves, neighboring soft tissues are not damaged by these types of blades because the blade’s edge effectively rebounds due to the elasticity of the soft tissue. Thus, the significant blood loss common with use of traditional bone saws is prevented. In addition, significantly more precise cuts are possible using ultrasonic bone cutting devices, in part, because the blade’s edge does not require serrations. Instead, a continuous and sharpened edge, similar to that of a typical scalpel, enables a user to better manipulate the surgical device without the deflection caused by serrations, which is common when using oscillating and reciprocating bone saws. Although ultrasonic cutting blades are advantageous in that they are less likely to tear neighboring soft tissues and more likely to produce relatively more even cuts, these types of blades still generate considerable amounts of heat.
As with traditional bone saws, separate or integrated irrigation systems are often utilized in order to flush the surgical site and generally provide some measure of cooling effect to the blade. However, many of these blades suffer from the same disadvantages as traditional bone saws that have tried to incorporate similar measures. For example, providing openings along the blade’s edge through which fluid flows introduces voids in the cutting edge, thereby inhibiting the cutting efficiency of the blade (See U.S. Pat. No. 5,188,102). In addition, these fluid openings can be readily compacted with surgical debris, rendering them useless for their intended function. In other blade designs, the continuity of the blade is maintained and a fluid outlet is positioned just before the blade’s edge (See U.S. Pat. No. 8,348,880). However, this fluid outlet merely irrigates the surgical site since it is positioned too far from the blade and bone interface to actually provide the necessary cooling effect. Also, it irrigates only one side of the blade. Another design for an ultrasonic cutting device, which claims to cool the blade, incorporates an irrigation output located centrally along the longitudinal axis of the blade (See U.S. Pat. No. 6,379,371). A recess in the center of the blade tip allows fluid to flow out of this output and toward the blade’s edge, flow that is propelled by a source of pressure. However, the positioning of this irrigation output within the contour of the blade tip results in a bifurcation or splitting of the irrigation flow, such splitting tending to distribute fluid at an angle away from the blade’s edge. Mentioned above, the excessive heat generated using any cutting blade, including an ultrasonic cutting blade, is focused most significantly at the blade and bone interface. This example for an ultrasonic blade with cooling capabilities, then, does little to actually cool the blade at the blade and bone interface, but instead serves merely to flush debris from the surgical site. Again, having copious amounts of irrigation fluid in the surgical site can hamper the surgeon’s ability to visualize important anatomic structures. Furthermore, this ultrasonic blade is not well-suited to cutting large cross-sections of bone and is used almost exclusively in spine, oral or maxillofacial surgeries, which involve cutting of small bones.
Even assuming that any of the irrigation systems incorporated into the various bone saws provide some measure of cooling, thermal burning of both neighboring soft tissues and bone surfaces remains a significant problem. Because the working surface of the blade also moves rapidly, considerable heat is generated along its length, too. The dynamic motion of the surface of the blade contacts neighboring soft tissues, potentially burning them. With respect to an osteotomy, as the blade passes through the cross-section of bone, the freshly-cut bone surfaces remain in constant and direct contact with the rapidly vibrating shaft of the blade. As a result, it is not uncommon to burn the bone, produce smoke and, more importantly, kill osteocytes. In fact, simply lengthening an ultrasonic blade to accommodate large cross-sections of bone tissue, for example, increases the surface area through which heat can transfer and, thus, is avoided by manufacturers of these types of blades. While irrigation directed specifically toward the blade’s leading edge may provide some measure of cooling at the blade and bone interface, irrigation alone is insufficient in trying to avoid prolonged exposure of bone tissue, for example, to temperatures in excess of 47° C. Therefore, there remains a need surgical device that is capable of cutting bones with large cross-sections, such as the femur, while maintaining a working temperature along the entirety of the blade shaft that does not inhibit proper healing of the bone tissue.
In some applications, there is a need to protect one side of the cutting plane versus another. For example in total shoulder or total knee replacement, a planar cut may be needed to seat an implant on one side. Protecting the viability of the bone can allow for the use of a cementless implant to allow for bone in-growth/osteointegration, where the other side of the cut temperature reduction is not required.
For at least the aforementioned reasons, there is a need for improved surgical devices and techniques.
Having thus described the presently disclosed subject matter in general terms, reference will now be made to the accompanying Drawings, which are not necessarily drawn to scale, and wherein:
The presently disclosed subject matter medical cutting devices with a static casing and a blade working body of greater width and related methods. According to an aspect, a cutting device includes a static casing having a width of substantially a first distance. The cutting device also includes a blade working body including a first end and a second end. The first end is configured to operatively connect to a source of movement. The second end includes a cutting component. The blade working body has a width of substantially a second distance. The second distance is greater than the first distance.
The following detailed description is made with reference to the figures. Exemplary embodiments are described to illustrate the disclosure, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a number of equivalent variations in the description that follows.
Articles “a” and “an” are used herein to refer to one or to more than one (i.e. at least one) of the grammatical object of the article. By way of example, “an element” means at least one element and can include more than one element.
“About” is used to provide flexibility to a numerical endpoint by providing that a given value may be “slightly above” or “slightly below” the endpoint without affecting the desired result.
The use herein of the terms “including,” “comprising,” or “having,” and variations thereof is meant to encompass the elements listed thereafter and equivalents thereof as well as additional elements. Embodiments recited as “including,” “comprising,” or “having” certain elements are also contemplated as “consisting essentially of” and “consisting” of those certain elements.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. For example, if a range is stated as between 1% - 50%, it is intended that values such as between 2% - 40%, 10% - 30%, or 1% - 3%, etc. are expressly enumerated in this specification. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this disclosure.
Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.
As referred to herein, the term “cutting device” can be any suitable component movable for cutting into or generally transforming a material (e.g., bone). The cutting device can include a blade that operates through large or small (e.g., vibrations) mechanical motion. The motion can be in a specific direction(s). For example, the cutting device can be moved in an oscillating manner, flexing, bending, rotating, torsionally, longitudinally, and the like.
The cutting end 106 can be a blade tip configured to cut, ablate, abrade or otherwise transform, for example, bone or other tissue. The cutting end 106 includes a top surface 110 and an opposing bottom surface. The cutting end 106 defines at least one blade edge 112. In this example, the blade edge 112 has serrations for cutting, ablating, abrading, or otherwise transforming bone or other tissue. In the alternative, the blade edge 112 is a continuous, planar arc, and sharpened along its entirety for cutting, ablating, abrading, or otherwise transforming bone or other tissue.
The static casing 104 may be made of a material suitable for biomedical applications, such as ceramic, titanium, stainless steel, PEEK, PE, PTFE, or the like. The outer surface of the static casing 104 may be coated with a lubricant, such as a solid film or a fluid film, and/or any other insulative material. The blade working body 108 may be made of a material suitable for biomedical applications, such as titanium, stainless steel or the like. In embodiments, a lubrication film may cover the blade working body 108 and may be made of a solid film lubricant, or other suitable lubricant. Further, for example, static casing 104 may be coated with a lubrication film, such lubrication film being a solid film lubricant suitable for the application. The static casing 104 and the blade working body may be coated with the lubrication film.
It is noted that alternative to a blade working body 108, this component may be suitably configured as a horn for ultrasonic embodiments. Similar to the aforementioned description of the oscillating saw blade embodiment, an ultrasonic bone cutting device could leverage the same mechanism of preventing temperature from translating to the adjacent bone. The ultrasonic bone cutting device would still include a housing/handpiece that drives the working surface of the blade in a desired motion (e.g., longitudinal). The static casing would be rigidly attached/mounted to the housing which would decouple the dynamic motion of the ultrasonic blade relative to the static casing itself. The working surface of the ultrasonic blade would still be supported by the static casing since they would reside in contact adjacent to one another. The working surface of the ultrasonic blade can oscillate on the static casing, which can be made of an insulative material with material properties that minimize frictional sliding interactions. Similarly, a lubrication boundary may be included between the static casing and working surface of the blade to decrease friction during motion.
In accordance with embodiments, the static casing 104 may be used for receiving a load force applied by bone or other tissue when the blade tip is cutting, ablating, abrading, or otherwise transforming the bone or other tissue. This may be when the cutting end 106 is deflected by force applied to it towards the static casing 104. For example,
With continuing reference to
It is noted that embodiments of the present disclosure are described as producing or having oscillatory saw blade movement or any other suitable source for motion. It is noted that in the alternative the movement may be any suitable type of movement produced by any suitable source (e.g., such as an ultrasonic transducer driving the blade through piezoelectric elements and smaller vibrations)). Further, cutting may be applied to any suitable material or technical field. Suitable mechanical sources could include anything from piezoceramics, electro-mechanical motors, user generated hand motion, etc. However, its important to note that all types of mechanisms can produce equivalent types of movements. These could include, but are not limited to, axial motion, bending motion, torsional motion, flexural motion, etc. It is also feasible that the source of mechanical motion can combine all of these modes of motion to create more complex movements. Regardless of the motion and/or the manner in which it is produced, there would be a resultant motion at the end of the functional device/blade edge. This motion would, under the claims of this patent, be captured within the bounds of the static casing which function to share load, decouple motion, and prevent heat transfer to the functional working surfaces. Examples include oscillating/sagittal/reciprocating medical bone cutting saws, medical rotary drills, medical rotary burs, construction hammer drills, construction rotary hammer, wood cutting axes, construction oscillating multi-tools, oscillating medical cast saws, cutting saws, etc. The principles of the claims presented in this patent could be applied to all of these devices with equivalently realized benefits.
While the embodiments have been described in connection with the various embodiments of the various figures, it is to be understood that other similar embodiments may be used, or modifications and additions may be made to the described embodiment for performing the same function without deviating therefrom. Therefore, the disclosed embodiments should not be limited to any single embodiment, but rather should be construed in breadth and scope in accordance with the appended claims.
This application claims priority to U.S. Provisional Pat. Application No. 63/292,438, filed Dec. 22, 2021, and titled MEDICAL DEVICES AND RELATED METHODS FOR TRANSFORMING BONE, OTHER TISSUE, OR MATERIAL, the content of which is incorporated herein by reference in its entirety. This application is related to U.S. Nonprovisional Pat. Application No. ______, filed simultaneously herewith, and titled MEDICAL CUTTING DEVICES WITH STATIC COMPONENTS HAVING TEMPERATURE SENSORS AND RELATED METHODS. This application is related to U.S. Nonprovisional Pat. Application No. ______, filed simultaneously herewith, and titled MEDICAL CUTTING DEVICES WITH COOLANT MODULES AND CHANNELS AND ASSOCIATED METHODS. This application is related to U.S. Nonprovisional Pat. Application No. ______, filed simultaneously herewith, and titled MEDICAL CUTTING DEVICES HAVING A BLADE WORKING BODY THAT DEFINES AN OPENING FOR EMITTING COOLANT THEREFROM AND RELATED METHODS. This application is related to U.S. Nonprovisional Pat. Application No. ______, filed simultaneously herewith, and titled MEDICAL CUTTING DEVICES HAVING A WORKING BLADE BODY WITH STATIC COMPONENTS AND RELATED METHODS OF USE.
| Number | Date | Country | |
|---|---|---|---|
| 63292438 | Dec 2021 | US |
