Patent Application
20170258486
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This invention relates generally to the field of piezoelectric surgical devices and surgical tips thereof, and more specifically to a periosteal preparation tip and method of use thereof in a piezoelectric surgical device.
The periosteum is a membrane that covers the outer surface of bones in humans and animal, except at the joints of long bones. The periosteum consists of dense irregular, connective tissue that is divided into layers, and is attached to bone by collagen fibers in the bone matrix. The periosteum provides an attachment for muscles and tendons to the bone, as well as nourishment by providing the blood supply to the body from the marrow.
Periosteal damage can be caused by the separation of the periosteum from the bone during surgery. Surgical procedures often have adverse effects on the periosteum due to the manner in which the periosteum is prepared by separation from the bone. The preparation of the periosteum is a routine procedure, and is commonly performed by using a surgical elevator. In such a procedure, the surgeon uses a scalpel to cut through soft tissue to the bone, and then uses the surgical elevator to peel the periosteum from the bone. Periosteal elevators, which are specialized instruments used for separating the periosteum from the bone, are also commonly used to lift full thickness soft tissue flaps. Periosteal elevators allow a surgeon to manually lift and separate periosteal tissue from the bone by inserting the blade of the elevator between the periosteum and the bone.
It is difficult or impossible for surgeons to prepare the periosteum in such a way that it remains unharmed using current tools and methods, and therefore this procedure often causes damage to the cells of the osteogenic layer. Conventional preparation instruments do not detach the periosteum as a whole from the bone, but instead disrupt its integrity by tearing it. Such instruments, and the procedures in which they are used, damage important regenerative cells of the periosteum, which are thus no longer available to provide nourishment to the bone they cover.
Ultrasonic instruments, which use high frequency vibrations, have been available for decades. Devices utilizing the piezoelectric effect for surgical purposes have been used since about 2000. Applications of piezoelectric devices include hard-tissue surgery, periodontal surgery, the removal of impacted teeth, apical surgery, and bone expansion. U.S. Pat. No. 6,695,847 to Bianchetti et al. describes a piezoelectric surgical device, and is hereby incorporated by reference.
Piezoelectric surgery tools have become an established technique for dental and other surgeries. The characteristic feature of the piezoelectric surgical tool system is preservation of soft tissue, because mineralized tissues are altered by frequencies above 20 kHz while soft tissue (e.g. nerves) damage occurs only by vibrations at frequencies above 50 kHz.
Piezoelectric devices can cut a specific type of tissue without causing damage to adjacent tissues, based on the frequency of vibration. In addition, piezoelectric devices have the advantage of causing minimal bleeding when they are used to cut bone. This reduces the risk of postoperative infections.
Piezoelectric surgical devices vibrate an instrument at high frequency to affect human and animal tissue. Such devices utilize a variety of removable tips to perform a variety of different functions, and the tips may be operated at various frequencies (or ranges of frequency) in order to have different effects on different types of tissue, including without limitation, bone, teeth, muscle, connective tissue and others. This is explained in more detail in U.S. Pat. No. 6,695,847 to Bianchetti et al., which is incorporated by reference herein.
A tip (which can also be called an “insert”, among other names) is removably mounted to the main body of the piezoelectric apparatus that is comfortably held by a human hand, and the ultrasonic vibrations generated thereby are transmitted to the tip. When the tip makes contact with the tissue that is to be affected, the rapid movement of the tip in contact with the tissue has the desired effect on the tissue. When the instrument is used properly, the surrounding tissue that is not to be affected by the chosen tip and frequency range is not harmed, even if the surrounding tissue is contacted by the tip.
Disclosed herein is an insert and a method of using the insert. The insert is designed for use with a vibrating surgical tool, and has a proximal end for mounting to the vibrating surgical tool and a shaft extending from the proximal end. A head is mounted to the shaft and has a head thickness substantially less than the head width. The head is curved through the head thickness, along the longitudinal axis of the insert, and the terminal end of the head defines an edge for disposing against an incision between bone and covering periosteum.
In a preferred embodiment, the tip includes a passage formed through the shaft to permit water or another liquid to be forced through the passage. At least one liquid-dispensing aperture formed on one side of the insert is in fluid communication with the liquid passage. In another embodiment, a second liquid-dispensing aperture is in fluid communication with the liquid passage and is formed on a second side of the insert opposite the first side for dispensing liquid from the second liquid-dispensing aperture. The liquid dispensing apertures may be formed on the head adjacent the shaft, and may be formed on opposite sides of the head.
The edge may be formed on the terminal end of the head, and may be along a curve extending from one lateral side to an opposite lateral side so that the terminal end of the insert is the apex of the curve and is centrally located on the insert. The edge may extend from a front face to a tapered rear surface and may be at least about 1.0 millimeter wide. A front face of the head may form an angle with a longitudinal axis of the shaft of about 28 degrees.
Disclosed herein is a method of separating at least a portion of a periosteum from a bone. The method comprises the step of mounting a removable insert on a vibrating surgical tool. The insert has a proximal end removably mounted to the vibrating surgical tool and a shaft extending from the proximal end. A head mounts to the shaft and the head has a head thickness substantially less than a head width. The head curves through the head thickness along the longitudinal axis of the insert, and a terminal end of the head defines an edge. Another step of the method is vibrating the tip at high frequency. The edge is disposed against an incision between bone and a periosteum covering the bone and manually displaced along the length of the incision.
The method may include forcing a liquid through the shaft and out of the insert adjacent the head on opposing sides of the head. The method may include disposing the longitudinal axis at an angle of between about 0 and 90 degrees relative to the incision, and may include disposing the longitudinal axis of the shaft at an angle of between about 15 and 30 degrees relative to the incision.
In describing the preferred embodiment of the invention, which is illustrated in the drawings, specific terminology will be resorted to for the sake of clarity. However, it is not intended that the invention be limited to the specific term so selected and it is to be understood that each specific term includes all technical equivalents which operate in a similar manner to accomplish a similar purpose. For example, the word connected or terms similar thereto are often used. They are not limited to direct connection, but include connection through other elements where such connection is recognized as being equivalent by those skilled in the art.
The insert 10 shown in
The head 30 is shown in a magnified view in
As is shown in
A curved portion 34 is formed between the shaft end 32 and the edge 36 on the front face of the head 30, and between the shaft end 32 and the angled surface 38 on the rear face of the head 30. The curved portion 34 has rounded lateral sides 34a and 34b, and a radius of curvature along the longitudinal axis of the insert 10 of about 6.0 millimeters, but this can vary by at least about 1-3 millimeters greater or lesser. The corresponding curvatures at the front and rear faces of the head 30 maintain a consistent thickness of the portion of the head 30 that extends from the shaft end 32 to the angled surface 38, which is then followed by a tapered, decreasing thickness to the edge 36. This consistent thickness of the head 30, which may be about 1.0 millimeter+/−0.1 millimeters, allows insertion of the head 30 past the tapered surface 38 into narrow spaces during use.
It should be noted that the sizes of the portions of the insert 10 described above are defined in functional terms based on how the insert responds to ultrasonic vibrations and surgical action (back-and-forth movement, etc.). For example, the preferred insert 10 may be made of stainless steel, titanium or an alloy with a titanium nitride coating, and this material is cryogenically heat-treated by quenching and stress-relieving to obtain a hardness of between 57-61 HRC. Any alternative material and treatment that is suitable may be used instead. The response to ultrasonic vibrations of an insert made of this material and useful for human surgeries generally includes resonating at a frequency between about 25 kHz and about 29 kHz and a longitudinal direction of the movement that is triggered by the vibrations. Response to surgical action also includes the ability of the insert 10 to operate efficiently, according to its overall size and the sharpness of its operative portion, such as the edge 36. In this regard, a critical length in relation to the vibrating system of the transducer and the insert may be 32.6 mm+/−1 mm and a functional angle of the operating portion of about 28°+/−5°, as described above. In the embodiment of
At the shaft end 32 of the head 30 there are apertures 42 and 44 in fluid communication with an irrigation channel 40 that extends at least a portion of the length of the insert 10 from the bore 14, along the shaft 16 and into the head 30. Conventional piezoelectric surgical tools are equipped to force water into an insert, and this channel 40 receives pressurized water from the tool. The channel 40 splits adjacent the shaft end 32 of the head 30 and opens to the apertures 42 and 44 to allow irrigation fluid that is pumped into the bore 14 to flow out of the apertures 42 and 44. The irrigation system, made up of the channel 40 and apertures 42 and 44, causes irrigation fluid, such as water, to flow to both sides of the head 30 during use. Because the apertures 42 and 44 are mounted on opposite sides of the head adjacent the shaft end 32, liquid, such as water, may be sprayed or otherwise conveyed out of the apertures 42 and 44 to the surgical site, thereby cooling the tissue and the head 30. The apertures 42 and 44 may be on the shaft or on the front and rear faces of the head 30 as shown. The apertures may not be opposing, but this is preferred.
As shown best in
The use of the insert 10 will now be described in association with
The edge 36 extends into the incision and, due to the high frequency vibrations of the insert 10, the edge 36 further opens the existing opening between the bone and the periosteum. With some back-and-forth movement of the edge 36 along the opening in the periosteum, the periosteum is separated from the bone due to the edge 36 being driven by high-frequency, low-amplitude movements in the lateral and longitudinal directions. The edge 36 does not cut the periosteum, but rather is inserted between the periosteum and the bone, and continues to separate the periosteum from the bone along the path through which the edge 36 is conveyed by the surgeon. These back-and-forth movements, along with forces applied by hand in the axial direction (along the axis of the shaft 16) and/or the lateral direction, cause the edge 36 to further insert between the bone and the periosteum by separating the periosteum as a layer from the bone. Further movement along the incision causes further insertion of the head 30, so that with a gentle but firm back-and-forth movement, while maintaining the edge 36 in contact with both the periosteum and the bone at the junction of the two, the vibratory force of the edge 36 at the point where periosteum attaches to bone extends the separation. No tissue layers are incised by the insert 10, but the periosteum remains intact and separates as an intact layer from the bone.
As noted above, the openings 42 and 44 permit irrigation fluid, such as water, to flow, spray (such as by atomization) or otherwise contact the tissue at and near the front face and the rear face of the head 30 at and near the edge 36. The water preferably contacts both the bone and the periosteum to reduce their temperature, lubricate the edge 36, avoid dehydration of the tissue, and flush loose fragments of tissue away from the site where the separating of periosteum from bone occurs.
It should be pointed out that the edge 36 is always maintained to remain sharp enough to separate the periosteum from the bone, but not sharp enough to incise through the periosteal layer without misuse of the insert 10 by the surgeon. To have these characteristics in the insert 10 described herein, the edge 36 is always about 1.0 millimeter wide or wider, and is not sharpened sufficiently to incise the periosteum.
This detailed description in connection with the drawings is intended principally as a description of the presently preferred embodiments of the invention, and is not intended to represent the only form in which the present invention may be constructed or utilized. The description sets forth the designs, functions, means, and methods of implementing the invention in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and features may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the invention and that various modifications may be adopted without departing from the invention or scope of the following claims.
