Chain saw, component for a chain saw, and system for operating a saw

Abstract

Improved chain saws, chain saw components, methods of manufacturing chain saws and components, and methods of using chain saws and components are disclosed. In some embodiments, a chain saw includes a bar and a plurality of links, where a first link has a hook that engages a recess of a second link, thereby coupling the first and second links and allowing them to articulate without separating. The bar can have a track and the links can have a groove such that the links straddle the track. The track can have a protrusion and the groove of the link can have a notch that accommodates the protrusion such that the protrusion prevents the link from misaligning. The links can have tapered or pyramidal cutting teeth. The chain can be bidirectional. Robotic and automated operation of saws and other instruments are also disclosed.

Description

[0001] Cross-references to related applications.

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 058,216, filed July 29, 2020; U.S. Provisional Application Serial No. 63 / 085,290, filed September 30, 2020; U.S. Provisional Application Serial No. 63 / 147,033, filed February 8, 2021; U.S. Provisional Application Serial No. 63 / 154,379, filed February 26, 2021; U.S. Provisional Application Serial No. 63 / 209,540, filed June 11, 2021; and U.S. Provisional Application Serial No. 17 / 443,646, filed July 27, 2021. The entire contents of these earlier applications are incorporated herein by reference. Technical Field

[0003] This disclosure relates to chainsaws, components for chainsaws, methods of manufacturing chainsaws and components, and methods of using chainsaws and components. This disclosure also relates to systems for robotic and automated surgical procedures, particularly orthopedic surgical procedures such as knee or spinal surgery. Background Technology

[0004] Many people suffer from orthopedic surgical conditions that require the removal of bone or other tissue. For example, many people have serious joint conditions that require surgery to implant artificial joints. Every year, doctors implant millions of artificial joints in surgery that requires reshaping the patient's bone to accommodate the implant. The most common joint surgery is knee replacement. Bone reshaping in knee replacement involves making a series of flat incisions at the ends of the two major adjacent long bones that will be connected by the implant. Ideally, these incisions are precisely complementary to the shape of the implant. The flat surface of the healthy bone relative to the similar surface of the implant results in the strongest healing and a lower chance of complications or implant failure.

[0005] The requirements for sawing bone or other tissue during surgery exceed those for other saw applications. Specifically, in surgery, the saw must be sterile, the saw handle must be easily controlled by the surgeon, and vibration and loud noise must be minimized. Additionally, the saw must perform the cutting in a manner that does not generate excessive heat, the process must not leave metal particles or other contaminants in the surgical area, and, among other considerations, the process must cut hard bone or other tissue while minimizing damage to adjacent soft tissues, etc.

[0006] Bone is a living material containing cells that reform and fight infection. Importantly, after cutting, the hard part of the bone must remain intact, and the bone must not be deactivated (the cells within the bone are killed). Deactivated bone heals poorly and has lower resistance to infection. In implanted joints, when bone is deactivated, the interface between the bone and the implant is damaged, increasing the chance of failure.

[0007] One cause of bone deactivation is excessive heat generated by friction between the cutting device and the bone. Without precautions, bone temperatures can exceed 200°C. It is important to avoid high temperatures to prevent thermal necrosis, which kills cells due to heat or otherwise damages or delays bone cell healing due to thermal effects. Bone temperature can be controlled by shorter cutting times and water rinsing. However, this prolongs the overall process time, and rinsing obscures the cutting area and exposes it to splashes from the vibrations of the cutting device.

[0008] Residue from the bone incision must be removed from the body. Preferably, the debris from the bone incision is a mixture of powdery bone and bodily fluids. This paste should be removed from the cut area. Leaving large pieces of bone is not desirable; if they deposit in the tissue, they can act as foci of infection.

[0009] Bones have varying degrees of hardness. Cortical bone, the load-bearing bone tissue on the outside of long bones, is relatively hard. In contrast, cancellous bone, the bone marrow tissue inside long bones, is relatively soft. Many different types of bone tissue and hardness exist.

[0010] The cut produced by a bone saw is ideally flat in the plane of the shaft and straight at the cut boundaries. This is necessary to allow for optimal healing when two bone surfaces are facing each other or when one bone surface is facing the implant surface. Surfaces that are not in the same plane or are uneven create gaps, which take a long time to heal or may never heal. Some saws tend to experience a deviation from the intended plane of the saw shaft, a phenomenon known as scraping, which is undesirable. Furthermore, some saws have a cutting element that tends to experience a gripping motion that results in unguided movement of the shaft, which is also undesirable.

[0011] In surgical procedures, bone saws are controlled by surgeons in the operating room environment. Preferably, the saw produces minimal vibration so that it can be easily controlled by the surgeon. This is important for several reasons. Bone is often located near vital and fragile soft tissues, such as blood vessels and nerves, and uncontrolled movement can cause damage to these tissues. Furthermore, uncontrolled movement can result in less than desired cuts.

[0012] Saws are preferably thin. In common applications, it is desirable to minimize the amount of bone removed when cutting bone. Furthermore, there are many other orthopedic indications that require small saws; one example is surgical implants in the vertebrae. Therefore, a saw design that can be manufactured in a sufficiently small size to operate as intended is desired.

[0013] In typical bone cutting processes, the device currently used for cutting bone is the sagittal saw. This saw has a rectangular shape with its cutting edge at one end. The cutting edge moves from one side to the other in an arc, much like a pendulum. This movement is performed at an extremely high rate, up to 20,000 times per minute.

[0014] The sagittal saw has several drawbacks. Due to its rapid movement and the large forces used, the sagittal saw generates significant vibration, making it difficult for surgeons to use precisely. The sagittal saw is quite noisy; in fact, noise-induced hearing loss is an occupational hazard for operating room staff. Metal particles can scrape off the sagittal saw and deposit in the wound. The high speed of the sagittal saw can also lead to the spread of airborne pathogens, which is harmful to patients, sterile areas, and related medical personnel. The high speed of the sagittal saw also generates heat in the bone. This heat can kill cellular components within the bone, thus hindering bone healing. To reduce heat, surgeons often limit the continuous use of the sagittal saw. However, this prolongs the overall procedure time. The sagittal saw often deviates from its intended path, resulting in a curved rather than flat bone surface. For these and other reasons, the sagittal saw is not ideal.

[0015] Chainsaws have long been used in applications such as wood cutting; however, they have not yet been successfully deployed for general surgical purposes. This is because chainsaws face many technical challenges for the specific requirements of bone or other surgical procedures. U.S. Patent No. 9,616,512, granted to Viola, discloses a chainsaw for cutting bone. The disclosure of U.S. Patent No. 9,616,512 is incorporated herein by reference in its entirety. The embodiments described herein improve the safety and effectiveness of surgical chainsaws for cutting bone or other tissues.

[0016] Robotic systems for orthopedic surgery are known and used. Some embodiments of this disclosure relate to robotic or automated systems that have one or more advantages over such existing systems.

[0017] An example type of system using robotics is an orthopedic stereotactic instrument used for guidance during orthopedic surgery. Such a system typically includes a camera, a computer, and a tracking array. The tracking array is placed in a fixed position on the patient, the camera provides the computer with real-time images of the tracking array, and the computer converts the image data into positional data to track the patient's anatomy. The robot, equipped with surgical tools, can then be guided based on the positional data of the patient's anatomy.

[0018] An example of such a robotic system currently in use is the Mako Total Knee Arthroplasty (“TKA”) system, available from Stryker. The Mako TKA system includes a robotic unit with a robotic arm, a camera unit including a stereoscopic 3D camera, and a guidance module. The Mako TKA system also includes tracking arrays, including a femoral tracking array attached to the patient's femur and a tibial tracking array attached to the patient's tibia, as well as handheld probes that can be positioned at different locations by the surgeon. The tracking arrays and probes have reflective marking discs on them, allowing the camera to track their position. A saw attachment, such as a sagittal saw, can be attached to the robotic arm.

[0019] In use, the robotic unit is covered with a surgical drape and securely mounted to the floor. The camera unit is mounted on a post, which is also firmly positioned on the floor. The camera observes a tracking array on the patient's body, and the system converts the camera image data into positional information of anatomical points on the patient's body. Using this positional information, the system adjusts the position of the robotic arm and saw to the desired location on the patient's knee joint. As the patient's leg moves, the robotic arm readjusts based on visual feedback from the camera.

[0020] Other examples of stereotactic instruments for orthopedic surgery are known. For instance, the Rosa knee system, available from Zimmer Biomet, is another such instrument. Like the Mako TKA system, the Rosa knee system uses visualization of anatomical landmarks to position the robotic arm. The Rosa knee system's robotic arm can carry a cutting guide for guiding surgical incisions.

[0021] This existing system needs to be improved. Summary of the Invention

[0022] This disclosure relates to improved chainsaws, components for chainsaws, methods of manufacturing chainsaws and components, and methods of using chainsaws and components. Embodiments of this disclosure provide improved efficacy and / or safety in cutting bone or other tissues during surgical procedures.

[0023] In some embodiments, the saw bar includes a track, and the chain links have grooves such that the chain links straddle the track. The track may have protrusions, and the grooves of the chain links may have notches that receive the protrusions, thereby preventing the chain links from disengaging from the saw bar in a direction away from the chain path surrounding the saw bar.

[0024] In some embodiments, the chainsaw includes a saw shank and a plurality of chain links arranged as a chain around the saw shank, wherein a first chain link includes a hook that engages a recess of a second chain link, thereby connecting the first and second chain links together and allowing the first and second chain links to be hinged to each other without separating as the chain is driven around the saw shank. The chain links may have one or more cutting teeth oriented such that a cutting action results in a force in a substantially vertical direction, i.e., perpendicular to the path of the chain and into the saw shank. The chain links may have cutting teeth in a conical or pyramidal shape (including inclined pyramids). The chain links may have cutting teeth aligned along the lateral sides of the chain link. The tips of the cutting teeth may be aligned along the lateral sides of the chain link. Cutting teeth along one lateral side may be staggered relative to cutting teeth along an opposite lateral side.

[0025] In some embodiments, a hard coating may be applied to the contact surfaces of the saw shank, i.e., the surfaces of the saw shank that contact the chain links, and / or the contact surfaces of the chain links, i.e., the surfaces of the chain links that contact the saw shank. The hard coating reduces friction and heat generation. The hard coating also reduces wear and can eliminate the need for lubricants, which is beneficial in medical environments where most lubricants would be unacceptable. The hard coating may be a diamond coating. Other example coatings include nitrides of titanium and titanium alloys, as well as other materials, which can be applied by vapor deposition or other processes. Hard coatings, such as diamond coatings or other coatings disclosed herein, may also be used to coat the cutting teeth of the chain links to obtain similar benefits regarding the reduction of friction, heat, and wear.

[0026] In some embodiments, the chainsaw may include a protective element for protecting the chainsaw as it passes through a guide cutting block. The protective element may include a first guide post adjacent to the chain and spaced apart from the chain along a first longitudinal side of the saw shank, and a second guide post adjacent to the chain and spaced apart from the chain along a second longitudinal side of the saw shank. The guide posts may be wider than the chain. The guide posts may be retractable. In other embodiments, the protective element may be a retractable cap.

[0027] In some embodiments, a method of orthopedic surgery may include operating the chainsaw chain in a first direction to cut bone, and operating the chainsaw chain in a second direction opposite to the first direction. The cutting teeth may be symmetrical or asymmetrical, such that the cutting functions are the same or different in opposite directions.

[0028] In some embodiments, the method of orthopedic surgery may include cutting a precise excavation volume in the bone with a chainsaw and inserting an implant precisely shaped to the excavation volume into the bone.

[0029] In some embodiments, systems and methods are provided for manufacturing links for chainsaws. In some embodiments, systems and methods are provided for low-cost sharpening and / or contouring of cutting teeth of chainsaws and other saws.

[0030] In some embodiments, a method of manufacturing a chain link for a chainsaw includes using metal injection molding to form a chain link having a first lateral side, a second lateral side, and a plurality of cutting teeth, and using grinding (e.g., double-disc grinding) to grind the first lateral side and the second lateral side of the chain link.

[0031] In some embodiments, methods of orthopedic surgery may include robotically controlled chainsaws cutting bone.

[0032] In some embodiments, a robotic system for surgical purposes includes an arm comprising a first end and a second end, wherein the first end of the arm is adapted to connect to a patient's bone. The second end of the arm is adapted to connect to one of an instrument, a robotic arm, or a computerized robotic unit including a robotic arm. The robotic arm may be configured to carry an instrument, such as a bone saw or a guide for the bone saw.

[0033] In some embodiments, an automated system for surgical purposes includes a chainsaw configured to cut bone, a feedback system configured to measure one or more states of the chainsaw while it is operating, and a control system configured to receive information from the feedback system and automatically change the input to the chainsaw based on the feedback to alter the operation of the chainsaw.

[0034] Other examples and features of embodiments of this disclosure will become apparent from the accompanying drawings and detailed description. Attached Figure Description

[0035] The accompanying drawings illustrate examples of the apparatus, components, and methods disclosed herein, and together with the description, serve to explain the principles of this disclosure.

[0036] Figure 1 An example embodiment of a chainsaw box according to this disclosure is shown.

[0037] Figure 2 A single link of the cutting chain of a chainsaw is shown, such as... Figure 1 The cutting chain of the medium chainsaw box.

[0038] Figure 3 A schematic diagram showing the layout of the cutting teeth of the chain link is shown.

[0039] Figure 4A An example embodiment of a saw bar that can be used in a chainsaw according to this disclosure is shown.

[0040] Figure 4BAlternative example embodiments of saw blades that can be used in chainsaws according to this disclosure are shown.

[0041] Figure 5A A partial sectional view is shown. Figure 4A An enlarged view of the saw bar, showing a series of chain links assembled on the bar.

[0042] Figure 5B It shows Figure 4A An enlarged end view of the saw bar at the far end, showing a single link.

[0043] Figure 5C yes Figure 5B A magnified view of a portion of the image.

[0044] Figure 6A An exploded view of the drive wheel tooth assembly of a chainsaw according to this disclosure is shown.

[0045] Figure 6B It shows Figure 6A Side perspective view of the drive gear assembly.

[0046] Figure 6C It shows Figure 6A Top perspective view of the drive gear assembly.

[0047] Figure 7A An example of a saw bar with a sprocket is shown.

[0048] Figure 7B An example of a saw bar with a hard coating and no sprocket is shown.

[0049] Figure 8 An example embodiment of a chainsaw with guide posts according to this disclosure is shown.

[0050] Figure 9A An example embodiment of a chainsaw with a protective cap according to this disclosure is shown.

[0051] Figure 9B It shows Figure 9A In one embodiment, the protective cover is in a retracted state.

[0052] Figure 9C An example embodiment of a chainsaw is shown, in which the cutting element is in a retracted state.

[0053] Figure 9D It shows Figure 9C In one embodiment, the cutting element is in an extended state.

[0054] Figure 9E An example embodiment is shown for use with a chainsaw bar that passes through a cutting guide.

[0055] Figure 10An example of a chainsaw according to this disclosure is shown, illustrating the attachment of the chainsaw drive head to the chainsaw box.

[0056] Figure 11A The diagram illustrates a chainsaw cutting a chain link using existing technology.

[0057] Figure 11B It shows the normal position. Figure 11A A cross-sectional view of a link in the existing technology.

[0058] Figure 11C It shows the position of the lateral displacement. Figure 11A A cross-sectional view of a link in the existing technology.

[0059] Figure 11D It shows the tilted position Figure 11A A cross-sectional view of a link in the existing technology.

[0060] Figure 11E It shows Figure 11A A side view of the existing technology chain.

[0061] Figure 11F It shows Figure 11A A top view of the existing technology chain.

[0062] Figure 12A An example arrangement of the cutting elements on three sides of the chain link is shown.

[0063] Figure 12B An example arrangement of the cutting elements on two inclined surfaces of the chain link is shown.

[0064] Figure 12C An example arrangement of the cutting elements on the top surface of the chain link is shown.

[0065] Figure 12D An example arrangement of cutting elements on the top surface of a link is shown, wherein one row of cutting elements is along one lateral side of the link, and another row of cutting elements is along the other lateral side of the link.

[0066] Figure 13A Another example of a saw bar with a track containing links, the links having grooves for fitting the links onto the track.

[0067] Figure 13B It shows Figure 13A A schematic diagram of an embodiment.

[0068] Figure 13C It shows Figures 5A-5C Another view of the illustrated embodiment.

[0069] Figure 13D It shows Figure 13C A schematic diagram of an embodiment.

[0070] Figure 13E A schematic diagram of another example of a saw bar with links is shown.

[0071] Figure 14A A top perspective view of an example shaped implant for use in the vertebrae is shown.

[0072] Figure 14B It shows Figure 14A A perspective view of the bottom of the implant.

[0073] Figure 14C A precisely shaped excavated volume is shown for use in receiving. Figures 14A-14B The vertebrae of the implanted vertebrae, the excavation volume of which can be achieved through certain embodiments of this disclosure.

[0074] Figure 14D The present disclosure illustrates certain embodiments of cutting. Figure 14C Front view of a custom saw bar forming the bone space.

[0075] Figure 15A A top view of an example chainsaw with a surgical handle is shown.

[0076] Figure 15B It shows Figure 15A A side perspective view of a chainsaw with a surgical handle.

[0077] Figure 15C It shows Figure 15A Rear perspective view of a chainsaw with a surgical handle.

[0078] Figure 15D It shows movement in the first direction Figure 15A A chainsaw with a surgical handle.

[0079] Figure 15E It shows movement in the second direction Figure 15A A chainsaw with a surgical handle.

[0080] Figure 16 A protective device that can be attached to a chainsaw is shown.

[0081] Figure 17A A top view is shown of an example embodiment of a transmission mechanism for a chainsaw according to the present disclosure.

[0082] Figure 17B It shows Figure 17A Enlarged bottom perspective view of the transmission system mechanism.

[0083] Figure 18A A side view of another example embodiment of a transmission mechanism for a chainsaw according to the present disclosure is shown.

[0084] Figure 18B Shown from the first side of the chainsaw Figure 18A A perspective view of the transmission system mechanism.

[0085] Figure 18C Shown from the second side of the chainsaw Figure 18A A perspective view of the transmission system mechanism.

[0086] Figure 19 An illustration of an example mechanism for controlling the movement of a chainsaw is shown.

[0087] Figure 20A An example embodiment of a chainsaw with the saw blade in a horizontal position is shown.

[0088] Figure 20B This shows the saw blade in a vertical position. Figure 20A Chainsaw.

[0089] Figure 20C It shows Figure 20A A top view of a chainsaw.

[0090] Figure 20D This shows the saw blade rotating slightly to the right. Figure 20A Chainsaw.

[0091] Figure 20E This shows the saw blade rotating slightly to the left. Figure 20A Chainsaw.

[0092] Figure 21 A partial view of a chainsaw link after the metal injection molding step is shown.

[0093] Figure 22A It shows Figure 21 The first transverse side of the chainsaw link.

[0094] Figure 22B It shows Figure 21 The second transverse side of the chainsaw link.

[0095] Figure 23 The grinding steps are shown afterward. Figure 21 Example cutting teeth of a chainsaw chain link.

[0096] Figure 24 An example of a robotic system for surgical use is shown, which includes an arm that is attached to the patient's bone.

[0097] Figure 25 Another example of a robotic system for surgical use is shown, which includes multiple arms connected to the patient's bones.

[0098] Figure 26This is a flowchart of an example method for the automated control of a saw.

[0099] The accompanying drawings can be better understood by referring to the following detailed description. Detailed Implementation

[0100] To facilitate an understanding of the principles of this disclosure, reference will now be made to the examples shown in the accompanying drawings, and specific language will be used to describe these and other examples. However, it should be understood that the examples shown in the drawings or described herein are not intended to limit the scope of the claims. Any changes and further modifications to the systems, apparatus, components, or methods shown or described, and any further application of the principles of this disclosure, are fully contemplated as would normally occur to those skilled in the art to which this disclosure pertains. In particular, features, components, and / or steps described with respect to one embodiment of this disclosure may be combined with features, components, and / or steps described with respect to other embodiments of this disclosure.

[0101] The terms “first” and “second” as used herein do not imply any particular location or other characteristic. Rather, when used herein, they are used only to distinguish one component or part from another. The terms “attachment,” “connection,” “linkage,” etc., mean that one part is attached, connected, or linked to another part, either directly or indirectly through one or more other parts, unless otherwise specified. The term “user” refers to one or more persons who use the apparatus, system, and / or method described herein, such as one or more surgeons, physicians, operators, or other persons using the apparatus, system, and / or method.

[0102] Figure 1 A first example embodiment of a chainsaw case 10 is shown, which is suitable for bone or other tissue cutting in surgical procedures such as knee surgery, spinal surgery and other potential bone or tissue cutting applications. Figure 1 The chainsaw box 10 includes a saw bar 20, multiple chain links 40 assembled together with the saw bar 20 in the cutting chain, and a drive gear assembly 70.

[0103] Figure 2 A single link 40 of the cutting chain for a chainsaw is shown, such as Figure 1 The cutting chain of the chainsaw box 10. The chain link 40 includes a top side or cutting side 41, a bottom side or rod side 42, a first adjacent chain link side 43, a second adjacent chain link side 44, a first transverse side 45, and a second transverse side 46.

[0104] Link 40 has a hook 50 and a recess 52. Link 40 has a rounded feature or protrusion 54 that defines one side of the recess 52. In this example embodiment, the hook 50 extends outward from the second adjacent link side 44 and upward from the bottom side 42, and the rounded protrusion 54 extends downward from the top side 41 and inward from the first adjacent link side 43. The recess 52 extends upward from the bottom side 42 and is shaped to receive the hook 50 of the adjacent link 40.

[0105] like Figure 1 As shown, multiple links 40 can be linked together in the form of a chain to move along a predetermined path around the rod 20. A recess 52 of one link receives a hook 50 of an adjacent link, whereby the hook 50 is fitted into the recess 52. The hook 50 of one link thus interlocks with a rounded protrusion 54 of an adjacent link. When two adjacent links are in a configuration that aligns with each other or is not hinged, such as along the straight portion A of the rod 20, a gap is left between the tip 51 of the hook 50 and the end 53 of the recess 52, thus allowing hinged engagement. When two adjacent links are in a configuration that is hinged to each other along a convex path, such as along the convex curved portion B of the rod 20, the hinged engagement allows the hook 50 to further engage into the recess 52, and the distance between the tip 51 of the hook 50 and the end 53 of the recess 52 is less than the distance along the straight portion A. In some embodiments, at the maximum extent of the hinge, i.e., at the maximum extent of pivoting between adjacent links, the tip 51 of the hook 50 is located at the point closest to the end 53 of the recess 52, and in some embodiments may contact the end 53 of the recess 52.

[0106] The configuration of the link 40, with hook 50 and corresponding recess 52, allows the links 40 to pivot relative to each other and remain connected even when they pivot away from each other along a convex curved path. The links 40 remain connected, thus avoiding longitudinal disengagement of the hinge without the need for separate connecting elements such as rivets, pins, or other connectors. Therefore, the width of the chain is as thin as the width of the cut link 40, allowing for a thin chain for thin cuts.

[0107] like Figure 2 As shown, the bottom side 42 of the link 40 has a drive wheel tooth engagement recess 68. The drive wheel tooth engagement recess 68 is for engagement by the drive wheel tooth 72, as described in more detail below.

[0108] At the top or cutting side 41, link 40 has a plurality of cutting teeth 60. In the illustrated embodiment, each cutting tooth 60 is pyramidal in shape, tapering gradually from a relatively wide base 60B to a sharp or relatively sharp tip or apex 60A. The teeth are arranged in two parallel rows, each row extending along the lateral side of the top side 41 of link 40. Teeth 61, 63, and 65 are arranged along the first lateral side, and teeth 62 and 64 are arranged along the second lateral side.

[0109] Figure 3 A schematic diagram of the layout of the cutting teeth 60 of link 40 is shown, with the bases 61B, 62B, 63B, 64B, and 65B of teeth 61, 62, 63, 64, and 65 shown in solid lines. The bases 62B, 63B, and 64B of teeth 62, 63, and 64 are triangular and have a first dimension. The bases 61B and 65B of teeth 61 and 65 are triangular and have a second dimension, which is approximately half (including half and close to half) of the first dimension. Each of teeth 61, 62, 63, 64, and 65 is in the shape of an oblique pyramid, with the apex or vertex of the pyramid approximately above points marked 61A, 62A, 63A, 64A, and 65A, respectively. One side of each pyramid is approximately coplanar or flush with the lateral side of link 40. That is, each tooth 61, 63, and 65 has a lateral side that is approximately coplanar with the first lateral side 45 of the link 40, and each tooth 62 and 64 has a side that is approximately coplanar with the second lateral side 46 of the link 40. In the illustrated embodiment, the tips of the pyramidal teeth 61, 63, and 65, which are typically located above points marked 61A, 63A, and 65A, are aligned with the first lateral side 45 of the link 40, and the tips of the pyramidal teeth 62 and 64, which are typically located above points marked 62A and 64A, are aligned with the second lateral side 46 of the link 40.

[0110] When link 40 is arranged in a chain with similar links 40, tooth 61 is adjacent to tooth 65 of the adjacent link (as shown by the dashed line), and the adjacent teeth 61 and 65 together form a tooth profile similar to tooth 63. Similarly, when link 40 is arranged in a chain with similar links 40, tooth 65 is adjacent to tooth 61 of the adjacent link (as shown by the dashed line), and the adjacent teeth 65 and 61 together form a tooth profile similar to tooth 63. In other words, tooth 61 and the adjacent tooth 65 together form a tooth similar in size and shape to tooth 63. Therefore, when arranged in a series of links, the chain has two rows of teeth, where teeth 62 and 64 alternate along one transverse side 46, and teeth 63 and 61 / 65 alternate along another transverse side 45.

[0111] One result of this configuration is that the tooth tips are located on either side of the cutting surface, with valleys in between. The cutting teeth on opposite sides are staggered, aligning the valleys between the tooth tips on one side and the tooth tips on the opposite side. This reduces the time interval between cutting impacts, thus minimizing vibration while allowing space for bone chip removal. The shape and arrangement of the cutting teeth also promote chain alignment during cutting. That is, the geometry and arrangement of the cutting teeth result in self-alignment of the chain links.

[0112] Link 40 can have approximately the same width as the saw bar. In this case, because some pyramidal teeth have sides flush with the first lateral side 45 of link 40, and other pyramidal teeth have sides flush with the second lateral side 46 of link 40, the lateral surface of the link (including the teeth) and the bar is continuous and relatively smooth. This helps to produce a smooth surface for bone cuts.

[0113] The cutting width of the chain link should be equal to or greater than the width of the bar so that the saw does not get stuck. For the chainsaw to penetrate the bone, the kerf width created by the chain must be equal to or greater than the width of the bar. If the bar is wider than the kerf, it will extend beyond the kerf and be confined by the bone. In some embodiments, such as Figure 2 and Figure 3 In the example shown, the pyramid or cutting element is located on the side of the link and does not extend laterally beyond the width of the saw bar. In other examples, the pyramid or cutting element may extend laterally beyond the side of the link and / or beyond the width of the saw bar.

[0114] Cutting teeth can have other shapes and arrangements. Teeth can be shaped into other types of cones; a pyramidal shape is one example. A pyramid is a cone with a polygonal base. In the example shown, the base of the cone or pyramid is triangular, but other base shapes with 4, 5, 6, 7, 8, or more sides can be used. There can be any suitable angle between the sides of the polygon. For example, if a triangular base is used, the triangle can have acute, 90-degree, or obtuse angles. Example triangles have 90-degree, 45-degree, and 45-degree angles at their corners, or 60 degrees at each corner, or other suitable angular arrangements. Other shapes that teeth can have include cones with round, elliptical, or irregular bases. The cone can be a regular cone or an oblique cone. For example, a tooth shaped as a pyramid can be a regular cone or an oblique cone. Any edge, vertex, or corner of the tooth can be sharp or rounded. Vertices can be vertically oriented, or they can be inclined or curved inwards and / or outwards. Other shapes that teeth can have include concave shapes with cutting edges designed to scoop out material (like a spoon with a sharp edge). For example, this design can be used to scoop out large volumes of soft tissue, such as when excavating cartilaginous discs between vertebrae. Individual links or chains can be a mixture of cutting teeth with different sizes, heights, and shapes, including any of the teeth described above.

[0115] The configuration of the cutting teeth as described (e.g., as...) Figure 2 and 3(As shown) Orienting the cutting edges of the teeth toward the bone or other tissue to be cut allows the cutting teeth to act as cutting blades, which facilitates slicing of the bone or tissue. This slicing function contrasts with the slicing operation of conventional chisel-shaped teeth. Furthermore, the arrangement of the cutting teeth's surfaces, which are essentially coplanar with the lateral sides of the links, contributes to a relatively flat and smooth cut surface. Additionally, the configuration of the cutting teeth helps prevent blockage caused by fibrous tissue.

[0116] The cutting teeth are arranged along the lateral sides of the chain links, and there are valleys between them, which provide space for removing bone chips or other debris from the valleys between the cutting teeth. These valleys can also be used to propel fluids, such as sterile saline or other fluids, such as those used for cooling or rinsing. The valleys also provide channels for propelling drugs, such as those that inhibit bleeding, prevent infection, or prevent other negative cellular responses. The valleys can also be used to propel non-liquid or slurry-type products to facilitate the delivery of substances such as human growth hormone, calcium, bone substitutes, collagen, etc., in very small areas or in large volumes. The movement of the chain can also act as a conveyor for transporting substances. Chainsaws with valleys or channels between the cutting teeth, as described herein, can also be used to collect or harvest bone, for example, from the pelvic region of the iliac crest, for use as patient signature material, which is commonly used in spinal surgery. The bone is harvested by the cutting teeth and carried out of the patient via the valleys between the cutting teeth.

[0117] In some embodiments, it is desirable to have one or more cutting elements at the center of a link, between transverse rows of cutting elements along the sides. This is desirable for cutting between transverse rows. Therefore, in some embodiments, one or more links may have one or more central cutting elements, such as one or more chisel teeth or square teeth. Such one or more cutting elements do not need to be present on every link. For example, half or several, or even only one, link in the chain may have one or more such cutting elements.

[0118] Figure 4A The saw bar 21 that can be used in the chainsaw box 10 is shown. Figure 1 saw bar 20 and Figure 4A The saw bar 21 is similar, except that it has different holes 23 for securing the bar 21 to a suspension system attached to the drive head of the chainsaw. The saw bars 20 and 21 are generally planar, having a body 22 that contributes to the main strength and stability of the bar and allows the chain links to transmit normal loads relative to the downward cutting pressure, i.e., loads perpendicular to the chain path and directed towards the saw bar. The bar has two sides 24 and 26 along the longitudinal direction and a distal end 25. Figure 4AIn this embodiment, the distal end is curved or semi-circular. The rod has a recess at the proximal end 27 for receiving drive gear teeth. Sides 24, 26 have extensions 28 that facilitate the transfer of a continuous chain link from the rod to the drive gear teeth and from the drive gear teeth to the rod. The first longitudinal side 24, the second longitudinal side 26, and the distal end 25 define at least a portion of the chain path P around the saw bar 21.

[0119] Rods 20 and 21 can have various other configurations. For example, the distal end 25 can be symmetrical and semi-circular, such as... Figure 4A As shown, it can also have other shapes. In one alternative, such as Figure 4B As shown, the distal end 25A can be asymmetrical, presenting a bevel with a rounded end that protrudes more on one side of the saw than the other. The bevel can be relatively straight and angled relative to the longitudinal axis of the saw, such that one longitudinal side of the saw is longer than the other, and the bevel can have a rounded end where it transitions to the longitudinal side. This distal tip is desirable in some types of surgery to resist the lateral forces generated by the moving chain approaching a bone all the way forward.

[0120] Figure 5A An enlarged view of the first side 24 of the rod 21 at its proximal end 27 is shown, in which a portion of a series of links 40 are assembled onto the rod 21, as shown in a partial cross-sectional view. Figure 5B An enlarged end view of the rod 21 at its distal end 25 is shown, with a single link 40 shown for illustrative purposes. Figure 5C yes Figure 5B A magnified view of a portion of the image.

[0121] like Figure 5A , 5B As shown in Figure 5C, the rod 21 has a track 30 extending from the body 22 of the rod 21. The track 30 extends wholly or partially along the sides 24, 26 and the distal end 25 of the rod 21. The track 30 acts as a monorail along which the links 40 of the chain travel. The track 30 extends generally away from the body 22 of the rod 21. The track 30 includes a protrusion 32 extending laterally beyond one or both sides of the track 30. The protrusion 32 acts as a link lock or retaining element, which prevents the links 40 from disengaging from the track 30 in a direction away from the rod (i.e., in a direction generally perpendicular to the direction of travel of the chain).

[0122] Link 40 has a groove therein, such that link 40 is fitted onto and straddles monorail 30. For example... Figure 2As shown, the illustrated link 40 has a groove 55 that extends upward from the bottom side 42 of the link 40 to a portion of the path of the top side 41 of the link 40. The top end of the groove 55 is designated as the top end 56. The groove 55 extends parallel to the first lateral side 45 and the second lateral side 46 of the link 40 and lies between them. The groove 55 extends along the longitudinal length of the link 40, passing through a circular protrusion 54 from the first adjacent link side 43, through the link body 47 and the second adjacent link lateral side 44, and through the hook 50. The groove 55 includes a notch 57 extending laterally beyond one or both sides of the groove 55. The notch 57 is shaped to receive a protrusion 32 of the track 30.

[0123] like Figure 5C As shown, the groove 55 and notch 57 of link 40 accommodate the track 30 and protrusion 32 of rods 20 and 21 to allow link 40 to travel around rods 20 and 21 while preventing link 40 from disengaging from track 30 in a direction away from rods 20 and 21. In the illustrated example, when link 40 is assembled on track 30, there is a gap between the top of track 30 and the top 56 of groove 55. Furthermore, in this example, there is a gap between the bottom of notch 57 and the bottom of protrusion 32. This allows for some small movement or play in link 40 in a direction away from rods 20 and 21, perpendicular to the direction of travel of the chain around rods 20 and 21. Additionally, in this example, the width of groove 55 is slightly wider than the width of track 30. This allows for some small movement or play in the lateral direction of link 40 relative to rods 20 and 21, while track 30 and groove 55 prevent any undesirable excessive movement of link 40 in the lateral direction relative to rods 20 and 21.

[0124] The gap between track 30 and groove 55 also causes the vertical load from link 40 (i.e., the load in the direction perpendicular to the chain path pointing into the saw bar) to be borne by the body of the saw bar, rather than track 30 itself. The vertical force of the cutting pyramid from link 40 is transmitted directly from link 40 to the saw bar's slides or bosses 33 on both sides of track 30. Track 30 itself is not loaded by these vertical forces. This arrangement tends to press link 40 into place, while track 30 provides resistance to the lateral movement or swaying motion of the link.

[0125] In other words, boss 33 is the primary location bearing the normal downward load from the link. The tangential section at the bottom of link 40 (i.e., the tangential section at the bottom of hook 50 and protrusion 54) contacts bosses 33 on both sides of track 30. Due to groove 55, link 40 straddles track 30, with one side of link 40 contacting boss 33 on one side of track 30, and the other side of link 40 contacting boss 33 on the other side of track 30. This separation of contact between the right and left links provides inherent stability and planar control of the link relative to the rod. Bosses 33 withstand downward forces from link 40, thereby stabilizing link 40 and keeping it in the same plane as the rod. This helps ensure that the lateral side of link 40 remains substantially coplanar with the sides of rods 20, 21.

[0126] The protrusion 32 and the notch 57 can take any suitable shape to allow the link 40 to travel around the rods 20, 21 while preventing the link 40 from disengaging from the track 30 in a direction away from the rods 20, 21. For example, the protrusion 32 can have a circular, elliptical, polygonal, or irregular cross-sectional shape, and the notch 57 can have any suitable shape for receiving the protrusion 32 while holding the link 40 on the track 30. The protrusion can be symmetrical or asymmetrical and can extend from one or both sides, and the notch can also be symmetrical or asymmetrical and can extend from one or both sides.

[0127] In an alternative embodiment, the track 30 has a notch (similar to notch 57), and the groove 55 of the link 40 has a protrusion (similar to protrusion 32) that engages in the notch. This alternative arrangement (switching the positions of the protrusion and the notch) provides a similar link locking or retaining element as described above, thereby preventing the link 40 from disengaging from the track 30 in a direction away from the bar. The link locking feature (i.e., the protrusion or notch) on the saw bar can extend around the entire saw bar or only a portion of the saw bar.

[0128] To mount the chain onto the saw bar, the chain links can be interconnected. The end of the chain can then be placed on the end of the track 30, with the notch 57 of the end link 40 positioned around the protrusion 32. The chain can then be guided onto the track 30 in the direction of the track 30 and guided along the track 30 around the saw bar 20, 21. The chain is also fitted around the drive wheel teeth 72 and can be tensioned.

[0129] Figure 6A An exploded view of the drive wheel tooth assembly 70 of a chainsaw according to the present disclosure is shown. Figure 6B A side perspective view of the drive gear assembly 70 is shown. Figure 6C A top perspective view of the drive gear assembly 70 is shown.

[0130] The drive gear assembly 70 includes drive gear 72, which has a series of drive gear teeth 73 around its periphery. In operation, a series of links 40 move about the links 20, 21 and the drive gear 72, as... Figure 1 As shown. The drive wheel tooth 73 engages with the drive wheel tooth engagement recess 68 of the chain link 40. When the chainsaw box 10 is attached to the drive mechanism, the drive mechanism rotates the drive wheel tooth 72, thereby causing a series of chain links to move around the rods 20 and 21 due to the engagement between the drive wheel tooth 72 and the chain link 40.

[0131] In the illustrated example, the drive gear assembly 70 includes a body 74 having a plate or disc 75 and a central post 76. The central post 76 has a shaped hole or recess 77 with a hexagonal or other shaped cross-section for receiving a drive element. For example, the hole or recess 77 may mate with a gear of a power adapter. The drive gear assembly 70 also includes drive gears 72 and caps 78. The drive gear 72 may be manufactured as a unit with the plate 75 or as a separate part assembled to the plate 75. For example, the drive gear 72 may have a central hole sized to receive the post 76, such that the drive gear 72 is press-fitted onto the post 76 to abut against the plate 75. The cap 78 may also have a central hole sized to receive the post 76, such that the cap is press-fitted onto the post 76 to abut against the drive gear 72. Two or more parts of the drive gear assembly 70 may be fixed together by laser welding or other suitable processes.

[0132] In an example of assembling the chainsaw case 10, a series of chain links 40 can be assembled around the links 20, 21 and the drive gear teeth 72. The components of the chainsaw case 10 can be locked together by attaching a cap 78 to the remainder of the drive gear tooth assembly 70. Once the chainsaw case 10 is assembled, its components will not separate due to their interlocking and overlapping assembly and construction. Therefore, the chainsaw case 10 will not separate spontaneously. The chainsaw case 10 can be a disposable item, which can be aseptically packaged and sold separately from the power equipment used to drive the chainsaw chain. For example, the chainsaw case 10 can be supplied as a single component for attachment to the chainsaw drive head, such as... Figure 10 The chainsaw drive head 12 is described in further detail below.

[0133] A chainsaw may include mechanisms for determining the position of the chain around a bar. For example, a shaped hole or recess 77 for receiving a drive element may be a single-position key, such that the drive element is assembled in only one position. Therefore, the position of the drive element relative to the drive wheel tooth 72, and thus the position of the chain link 40, may be known. Additionally or alternatively, the drive wheel tooth assembly or other parts of the chainsaw may include position indicators, such as mechanical, magnetic, or optical encoders or Hall effect mechanisms, that provide feedback to the drive unit. Using such feedback, an operator or computer-operated control obtains information about the travel and / or positioning of the teeth. In an example embodiment, the chainsaw may have some sections of multiple teeth designed for a specific purpose. For example, the chainsaw may have sections with very small, non-erosive cutting features compared to the rest of the chain. By knowing the position of the chain, an operator or computer control can selectively position the sections of teeth as needed. For example, when inserted near sensitive soft tissue or other physiological tissues such as nerves or arteries, the less erosive cutting teeth may be positioned distally, and the chain may be oscillating to keep the less erosive teeth positioned distally. These less erosive teeth can be used to perform cutting as they slowly penetrate the bone. After the sensitive section has been treated, the chain can be manipulated to rotate continuously and expose the bone to the more erosive tooth profile.

[0134] A potential problem with conventional chainsaws is friction, such as the friction between the chain and the saw bar. Friction also generates heat, which can be detrimental in surgical procedures. For some existing chainsaws, to reduce heat, the bar must be rinsed with, for example, salt water, or the saw can only be used for very short periods of time.

[0135] According to some embodiments of this disclosure, to reduce friction, a very hard coating can be applied to the surfaces of the links 20, 21, or 40 that contact each other. A non-limiting example is a diamond coating. Hard coatings such as diamond coatings significantly reduce friction between the surfaces of the links and the links. This minimized friction reduces heat generation during sawing. This allows the saw to be used for longer continuous periods, thereby reducing the total process time. Hard coatings also reduce wear. Furthermore, with the use of hard coatings, embodiments of the chainsaws disclosed herein can operate without any external lubricant, which is beneficial for component cooling or lubrication. External lubricants would be disadvantageous because they can cause contamination. Additionally, flushing the links is reduced or eliminated. Flushing would be cumbersome because it can obscure the cutting view and may splash flushing fluid outside the operating area.

[0136] An unexpected discovery was that, using this coating, friction could be reduced to the point where a sprocket was no longer needed. Without this coating, the chain generates significant friction along its path around the curved distal end of the saw. To eliminate this friction, a sprocket can be placed at the distal end. Figure 7A An example of a saw bar SB1 with a sprocket SW is shown. This sprocket SW can rotate at a chain speed around the saw bar and effectively eliminates friction caused by sharp turns at the end of the saw bar.

[0137] Figure 7B An example of a saw bar SB2 is shown, which has a hard or friction-minimizing coating on the bar, such as a diamond coating, which eliminates the need for a sprocket SW. The elimination of the sprocket greatly simplifies the saw. This makes the saw bar easier and less expensive to manufacture, while simultaneously increasing its strength and greatly facilitating the production of miniaturized versions of the device.

[0138] As mentioned above, a hard coating that can be applied to the contact surfaces(s) of the saw shank and / or chain links can be a diamond coating. Other example coatings include titanium and titanium alloy nitrides, as well as other materials, which can be applied by vapor deposition or other processes. Hard coatings (such as diamond coatings or other coatings disclosed herein) can be used to coat all or any part of the saw shank and / or chain links. For example, a hard coating as disclosed herein can be used to coat the cutting teeth of the chain links, which can reduce friction, heat, and wear. The entire chain link can be coated with a hard coating, resulting in both the chain link surfaces in contact with the saw shank and the cutting teeth being coated.

[0139] Figure 8 Additional features that can be incorporated as part of a chainsaw or chainsaw system according to this disclosure are shown. Certain surgeries (such as, for example, knee replacement surgery or other orthopedic surgeries) may use cutting blocks, such as... Figure 8 The cutting block C is shown. Cutting block C has a window D through which the saw can be guided. In use, cutting block C can be fixed to the patient, such as to the bone, so that the saw is guided in the desired position to make an incision. Cutting block C fixes the position of the incision and helps prevent unwanted movement of the saw.

[0140] Because the chainsaw chain must pass through window D of the cutting block C, there exists a chain ( Figure 8 The danger of a chain link 40 (as shown) contacting the right or left inner side of the cutting block window D could lead to damage to both the chain link / chain and the cutting block C, as well as debris from them. Furthermore, because the chainsaw chain must pass through the window D of the cutting block C, the width of the window D should be greater than the width of the chain. However, this could lead to undesirable movement of the chainsaw and the possibility of a chain link / chain contacting the top or bottom surface of the cutting block window D, resulting in similar damage and debris problems.

[0141] according to Figure 8In one embodiment, the chainsaw includes guide posts 91, 92 extending forward on both sides of the saw bar 21 and spaced apart from the chain on the longitudinal sides 24, 26 (sometimes referred to as the top and bottom) of the saw bar 21, as shown. These stabilizing guide posts 91, 92 are rigidly fixed at their proximal ends (not shown) to a mechanism similar to the chainsaw housing 10, such as the chainsaw's drive head, such that the guide posts 91, 92 are fixed in position relative to the saw bar 21 and move together with the saw bar 21 as rigid components. That is, the guide posts 91, 92 are maintained at a fixed distance from the saw bar 21 on both sides of the saw bar 21.

[0142] Because the guide posts 91 and 92 are located on both sides of the saw bar 21, they prevent the chain from contacting the right or left inner side of the cutting block window D. Furthermore, the guide posts 91 and 92 are slightly thicker than the chainsaw itself. This ensures that the guide posts 91 and 92 contact the top and bottom walls of the cutting block window D. This prevents unwanted angular movement of the saw bar 21 and keeps the saw in a suitable position spaced apart from the top and bottom surfaces of the window D. Therefore, contact between the moving chain and the window surface is avoided.

[0143] To prevent the guide posts 91 and 92 from extending significantly beyond the far side of window D, each of the guide posts 91 and 92 is retractable along its longitudinal axis. Specifically, the guide posts 91 and 92 may have telescopic portions with stops 93 and 94 on their distal portions. When these stops 93 and 94 contact the entrance to window D, they cannot move further. As the saw bar 21 continues to advance through window D, the distal portions of the guide posts 91 and 92 are prevented from advancing by the stops 93 and 94, and the guide posts 91 and 92 shorten as their proximal portions extend into (or retract into) their distal portions. The guide posts 91 and 92 may be manufactured with sufficient strength to prevent bending, particularly at their fixed bases. To avoid the guide posts 91 and 92 obstructing the chainsaw's lateral cutting or hindering its forward movement or other positioning, it is advantageous to prevent the guide posts 91 and 92 from extending significantly beyond the far side of window D.

[0144] Figure 9A and 9B Another embodiment is shown for use with the cutting guide or block D. The chainsaw includes a cover 95 that acts as a block that passes laterally but also above and below the saw shank to directly prevent contact with the window D on all four sides. In some embodiments, the cover 95 can be reinforced by a connection between its upper and lower surfaces that passes through a slot 29 in the saw shank. Like the guide posts 91, 92, the cover 95 can be retractable, with the distal portion 96 retractable into the proximal portion 97, or vice versa. Figure 9BAs shown, the distal portion 96 of the cover 95 may have one or more stops to prevent distal movement beyond a desired point where further advance of the saw causes the cover 95 to shorten due to the telescopic folding of the distal portion 96 and the proximal portion 97.

[0145] Figure 9C and 9D Another embodiment is shown, used with cutting block C. In this embodiment, as... Figure 9C As shown, when the cutting elements 98 of the saw chain are in window D, they retract or rotate towards the center. Those cutting elements 98 that have already passed through window D can flare outwards, as... Figure 9D As shown. Outward movement can occur automatically, such as through spring action, or due to contact with bone.

[0146] Figure 9E Another embodiment is shown for use with the cutting block C. In this embodiment, the chainsaw bar has an arched side 80. The arched side 80 of the chainsaw bar prevents the cutting element 81 from contacting the inner surface of the window D of the cutting block C. The body of the chainsaw bar approaches the inner surface of the window D at the arched side 80, which keeps the saw in a stable position with minimal pitch within the window D and prevents the cutting element 81 from contacting the inner surface of the window D.

[0147] In some variations, the saw shank can be manufactured to mate with window D, for example, using a press fit, sliding fit, or slip fit. Some clearance around the saw shank allows the links to pitch at a small angle. One embodiment has a tight fit between the height of the guide opening and the width of the saw. Simultaneously, friction causing the saw to pass through the guide must be minimized. The shank can also be spring-loaded or covered with a deformable layer, so that the shank will be stabilized within window D but will still be able to move. The shank can be covered with a sheath that does not extend beyond the cutting block C. The links can be coated with titanium nitride or a similar material to minimize any wear or debris that would result when the links (e.g., made of stainless steel) contact the cutting block C.

[0148] Guide posts 91, 92, covers 95, or other similar longitudinal sliding elements or stabilizing guards can be computer-controlled or remotely controlled, such as by pneumatic, electromechanical, or other actuators. The posts, covers, sliding elements, or guards may also have feedback systems that allow the computer or operator to know their position. They may also include fiber optic or fiber optic cameras to aid in visualization. The reduced vibration of the chainsaw embodiments disclosed herein helps achieve this compared to the high vibration of a sagittal saw, which would make visualization via such components difficult or impossible. The posts, covers, sliding elements, or guards can also be used in conjunction with flushing to maintain a clear view.

[0149] Protective elements (such as the aforementioned posts, caps, sliders, or guards) prevent the rotating chain and saw bar from contacting the groove wall of the cutting block or guide, while maintaining the guiding function of the groove. Therefore, protective elements aid in chainsaw alignment while preventing undesirable movement of the chainsaw or unfavorable contact between the chainsaw and the cutting block or guide.

[0150] Figure 10 An example of a chainsaw is shown, illustrating the attachment of the chainsaw drive head 12 to the chainsaw housing 10. The saw blades 20, 21 are attached to the drive head 12 with fasteners through holes 23 for the suspension system (see...). Figure 4A The drive head 12 has a drive rotor that is rotated by a motor, which engages with the drive recess 77 of the drive wheel tooth assembly 70 to drive the chain of the chainsaw.

[0151] A chainsaw may include various components for driving the chain. The chainsaw may include a motor, such as a DC or AC motor, or an engine that generates power. The chainsaw may also include a drive mechanism that transmits power from the motor or engine to the chain. The chain may be controllable at variable speeds and torques.

[0152] The chainsaws and / or chainsaw components described herein offer advantages over certain prior art chainsaws and components. A common problem with most existing chainsaws is the stability of the chain and its links as the chain moves along the bar and when it is subjected to forces during cutting. The chain moves rapidly along the guide at the bar boundary. When it interacts with the material during cutting, it is subjected to forces that cause the chain links to move away from their normal positions. This is partly due to the shape of the cutting element, which often has cutting edges at the top and sides, such as... Figure 11A As shown, this diagram illustrates a chain link from a typical existing technology chainsaw. The two cutting edges generate various forces that tend to cause the chain link to move as it moves along the track G of the bar, such as... Figure 11B As shown. Figure 11B A cross-sectional view of a prior art link in its normal position is shown; Figure 11C A cross-sectional view of a prior art link in a laterally displaced position is shown; Figure 11D A cross-sectional view of a prior art link in an inclined position is shown; Figure 11E A side view of a prior art link is shown; and Figure 11F A top view of a prior art link is shown. The two cutting edges of the link generate various forces that tend to cause the link to... Figure 11C The lateral movement is shown, as follows: Figure 11D The tilt shown is as follows: Figure 11E Pitch as indicated by the middle arrow, and / or as shown by the middle arrow. Figure 11FThe rotation is indicated by the middle arrow. Furthermore, the cutting elements of the sequential links often face opposite directions. These movements impose high stresses on the connections between links and on the mechanical interactions between the links and the guide G. These stresses can lead to component failure. Therefore, the components need to be manufactured to be relatively large and bulky, making this prior art design impractical for surgical use.

[0153] Some embodiments of the link described herein (such as...) Figure 2 One advantage of the chain link shown is that the cutting element is designed to apply force primarily in the same plane as the saw bar. This primarily generates a single force vector that moderately pushes the chain link toward the bar, where the bar resists the normal force. For simplicity, this vector, perpendicular to the chain path and pointing toward the bar, will be referred to as vertical. This avoids the eccentric forces acting on the chain links of most existing chainsaws, resulting in less stress on the chain elements. This allows the chain design to be optimized for other aspects of the cutting process, minimizing chain failures, and leading to reduced vibration and increased human and robotic control over chainsaw cutting.

[0154] Figure 12A-12D The profile of a potential cutting element is shown, which limits the cutting element force to be applied primarily in the same plane as the rod. Figure 12D It is similar to Figure 2 A schematic diagram of the cutting tooth 60. The shape and positioning of the cutting element balance the transverse forces, thus leaving a net force vector perpendicular to the rod. Figure 12A In this configuration, tapered (e.g., pyramidal) cutting elements are arranged on three sides: the top of the link and the two lateral sides. The lateral forces are balanced again, leaving a net force vector perpendicular to the link. Figure 12B In this configuration, the link itself has a top with two inclined surfaces, and tapered (e.g., pyramidal) cutting elements are arranged on the two inclined surfaces at the top of the link. Figure 12A As shown, the lateral forces are balanced, thus leaving a net force vector perpendicular to the rod. Figure 12C In this configuration, a series of tapered (e.g., pyramidal) cutting elements are arranged on top of the chain link. For example... Figure 12A and 12B As shown, the lateral forces are balanced, thus leaving a net force vector perpendicular to the rod. Figure 12D In, similar to Figure 2 A series of tapered (e.g., pyramidal) cutting elements are arranged on top of the link, with one row of cutting elements along one lateral side of the link and another row along the other lateral side of the link. Figures 12A-12C As shown, the lateral forces are balanced, thus leaving a net force vector perpendicular to the rod.

[0155] like Figure 2Another advantage of the links shown and the various other links described herein is that the shape of the vertical cutting elements results in improved cutting and surgical outcomes. These shapes allow for straight incisions, which facilitates the removal of bone fragments, and allow for reduced chain speeds, minimizing friction and tissue damage. These shapes also allow for cutting in both directions of chain movement.

[0156] exist Figure 2 In the examples and various other embodiments described above, the cutting elements have a pyramidal shape. The pyramidal elements are capable of cutting bone with their tooth tips and removing bone fragments with their valleys. The tooth tips are relatively close to each other, such that during cutting, the bone is impacted by the small cutting elements at short intervals, thus minimizing vibration. In contrast, long intervals between impacts from the cutting elements would cause a sudden increase in impact force, resulting in saw vibration.

[0157] Another factor contributing to vibration is the shape of the cutting element. The cutting elements on a wood-cutting chainsaw have sharp, chisel-shaped cutting edges. These elements scrape away a piece of material. These chisel-shaped cutting elements, such as the thin pyramidal teeth disclosed herein, impact the bone more forcefully. Furthermore, even when approached at an angle, the sharp tip of the pyramid disclosed herein immediately engages with or remains within the bone. In contrast, many other saw designs often jump to different locations when first applied to the bone.

[0158] Most chainsaws rotate in one direction, orienting their cutting element in that direction. Movement of the chain along the cutting edge is necessary, while movement in the opposite direction will not cut. One reason for this is that cutting materials such as wood requires a relatively complex cutting configuration with multiple parts. When cutting a fallen tree from the top side, only the bottom of the chainsaw bar can be used. When the chainsaw is then used to cut the lower surface of the log, the saw must be flipped so that the previous bottom of the bar is facing upwards. Because most saws are designed to be held in an ergonomic position, cutting the bottom of a log would be dangerous.

[0159] In orthopedic surgery, the ability to cut in two directions is an advantage. In some embodiments disclosed herein, such as... Figure 2 In the illustrated embodiment, the cutting surface includes symmetrical elements, thereby allowing for similar cutting action when the chain moves in either direction. In this case, the cutting effect is the same in both directions of chain movement. In an alternative embodiment, the cutting element may have cutting surfaces in both directions, but may be asymmetrical, with one side having a more aggressive configuration than the other. For example, the cutting teeth may be pyramidal in shape, with the cutting edge in one direction being sharper than the cutting edge in the opposite direction. Asymmetrical cutting teeth can perform different functions in opposite directions.

[0160] Cutting in two directions, or bidirectional cutting, is useful for removing debris that can interfere with the efficiency and directional control of the bone saw. Specifically, a saw cutting to the right can move the cutting edge toward the operator (clockwise), which efficiently removes debris. When the chain moves counterclockwise, a chain cutting to the left can remove debris better, again clearing debris toward the operator. Therefore, according to certain embodiments of this disclosure that favor bidirectional cutting, the cutting saw chain links can point toward the operator regardless of whether the saw is cutting to the right or left. Furthermore, when the cutting force is equal on both sides, the operator can more easily control the saw. Additionally, when approaching sensitive tissue, it is desirable for the chain at the cutting surface to rotate away from the operator to avoid unintentionally driving the saw toward sensitive tissue. A chainsaw with bidirectional cutting allows switching between cutting directions as desired.

[0161] Asymmetric cutting teeth can be useful for cutting different types of bone or tissue. The hardness of bone varies greatly in different regions. A single type of cutting configuration may not be efficient at cutting all types of bone. To take an extreme example, the outer layer of a long bone is made up of a very hard bone called cortical bone. Cortical bone performs the load-bearing function of a long bone. In contrast, the interior of a long bone contains bone marrow, where blood cells form. This substance, called cancellous bone, is very soft and its consistency is closer to that of soft tissue. Ideally, these types of bones should be cut with saws adapted to their different properties. Instead of two saws, a single saw with asymmetric cutting teeth, as disclosed herein, can be used, which performs different cuts depending on the chain direction. In one direction, the chain link can have a more aggressive cutting tooth surface, such as for cutting cortical bone, and in the opposite direction, the chain link can have a less aggressive cutting tooth surface, such as for cutting cancellous bone.

[0162] Furthermore, the surgical area around the exposed joint often contains multiple strands of undesirable soft tissue, such as ligaments overlapping the bone-cutting area. Therefore, in current sagittal saw surgery, the surgeon needs to remove the saw from the bone-cutting area and switch to different instruments, such as scissors or a scalpel, to cut this soft tissue. This is extremely time-consuming, especially for robotic systems where the entire system needs to be repositioned each time. In contrast, a chainsaw as disclosed herein can have a more aggressive bone-cutting element facing one direction of chain movement and a less aggressive soft tissue-cutting element facing the other.

[0163] Another challenge faced by surgeons is the presence of arteries and nerves directly on the surface of the bone. These structures are located very deep behind the cortical bone in the operating area when cutting long bones for knee replacement. Cutting the cortical bone in this area with an abrasive cutting instrument can easily penetrate the cortical bone and cause catastrophic damage. In these situations, a chainsaw, as disclosed herein, can function as an oscillating saw. The chainsaw can be switched to oscillating mode, rapidly alternating the direction of chain movement, causing the chain to move back and forth quickly over a very short distance—that is, a very small stroke or travel. This allows for the desired bone cutting while avoiding cutting tissue that should be preserved. For example, if a perforation occurs through the posterior wall of the bone, it causes minimal damage to the soft tissue.

[0164] To move the chain in a high-frequency oscillating motion with a very short stroke, the chain can be driven by ultrasound. This high-frequency motion generates heat. For this or other embodiments, one or more temperature sensors can be embedded in the chainsaw, such as in the saw bar.

[0165] Further advantages of some chainsaws, as disclosed herein, arise from the interface between the saw shank and the chain links. (The above refers to...) Figures 5A-5C An example of this is described. Figures 5A-5C A rod 21 is shown having a track 30 extending from the body 22 of the rod 21. As described above, the link 40 has a groove 55 such that the link 40 is fitted onto and spans the track 30.

[0166] Figure 13A Another example of a rod 34 with a track 35 is shown. The link 36 has a chisel-shaped cutting element and a groove for fitting the link onto the track 35, such that the link 36 straddles the track 35. Figure 13B A schematic diagram of rod 34, track 35 and link 36 is shown.

[0167] Figure 13C It shows Figures 5A-5C Another view of the illustrated embodiment. Figure 13D A schematic diagram of rod 21, track 30 and link 40 is shown. Figure 13D (Protrusion 32 not shown in the image).

[0168] In these embodiments, stability is enhanced by how the chain links mate with the bar. A novel design prevents lateral misalignment of the chain links and increases the chainsaw's lateral stability, in which the chain links straddle a single track on the saw bar. These embodiments provide greater strength to the overall mechanism and allow for greater flexibility in design.

[0169] One advantage of these embodiments is that they are compatible with saw chains in which the rod has grooves and the links ride in the grooves (e.g., Figure 11BCompared to a saw chain where the bar has grooves and the links ride in the grooves, the links are less likely to lean or sway laterally. Furthermore, the width of the link section above the saw bar can be greater (compared to a saw chain where the bar has grooves and the links ride in the grooves, for example...). Figure 11B This increases the area of ​​interlocking engagement between adjacent links. The increased width also allows for greater flexibility in cutting edge design. Furthermore, the monorail design increases lateral displacement and pitch resistance of the links. Another advantage is that the design simplifies the rod and reduces the stress it would otherwise experience. This allows the rod to be made from a variety of materials, including very hard plastics such as Corian or others. As a result, the rod can be manufactured more cost-effectively, such as through injection molding. The rod design allows some materials, such as certain plastics, to provide increased lubricity, thereby reducing friction.

[0170] In other embodiments, the rod may be made of a dielectric material, and the chain may be electrified to function as an electrocautery system. Such a chainsaw system could be used to cauterize blood vessels, which would help prevent excessive blood loss.

[0171] Such as Figure 13D In the illustrated embodiment, due to the gap between the track 30 and the groove 55, the vertical load from the link 40 is directly transmitted from the link 40 to the slides or bosses 33 of the saw bar 21 on both sides of the track 30. Therefore, the normal force from the link 40 is absorbed by the body of the saw bar 21, rather than by the track 30 itself.

[0172] Figure 13E A schematic diagram of another example of a rod 37 with a link 39 is shown. In this example, the link 39 has a downwardly projecting ridge 31 that fits into a corresponding slot 38 in the rod. The ridge 31 acts like a keel, thus providing stability to the link 39. Figure 13E The embodiments result in a robust link 39 guided along the rod 37. In one variation, the ridge 31 may have a laterally extending protrusion (e.g., protrusion 32) that fits into a complementary laterally serrated recess (e.g., recess 57) in the rod 37 in the side of the slot 38. In another variation, the wall of the slot 38 may have a laterally extending protrusion (e.g., protrusion 32) that fits into a complementary laterally serrated recess (e.g., recess 57) in the side of the ridge 31. These variations (with interlocking protrusions and recesses) provide similar link locking or retaining elements as described above, thereby preventing the link 39 from disengaging from the rod 37 in a direction away from the rod.

[0173] Further advantages of some chainsaws disclosed herein arise from the link locking mechanism. One example is the use of the protrusion 32 and the corresponding notch 57 as disclosed above.

[0174] In some existing chainsaws, if the chain breaks during cutting, the links will detach from the chain as individual parts. The inertia of a single link itself may not cause any significant injury; however, these parts will need to be removed from the operating area. This can be difficult at the depth of a bone incision or in soft tissue. Furthermore, some parts may fall from the surgical area and onto the surgical drape, making them difficult to locate.

[0175] One solution is to make the links magnetic. Loose links can be collected using magnets, making them easier to gather.

[0176] To prevent loss of chain links in the event of chain breakage, a chain link locking mechanism as disclosed herein can be used. One embodiment of the chain link lock is a protrusion from a track or other guide element used to retain the chain link, as described above. Figures 5A-5C As seen in the diagram, even small protrusions can prevent the links from detaching from the track. These protrusions can be symmetrical or asymmetrical. They do not need to surround the entire saw bar, but can be present only in certain sections.

[0177] Retaining the protrusions also has another advantage. Normally, a chainsaw moving at operating speed experiences forces as it curves around each end of the saw bar. The typical chain shape along the long side of the saw is not straight, but rather bends outwards. Therefore, typical sawing tends to produce a slightly curved shape. Using the chain link locking mechanisms disclosed herein, such as the protrusions 32 and corresponding notches 57, the chain is held against the bar, thus preventing this undesirable bending. The result is a cut with a straight transverse boundary.

[0178] The chainsaws disclosed herein can be combined with additional components for safety or other functions. For example, chainsaws as disclosed herein may include torque limiting devices, such as electronic torque limiters via motors or slip clutches integrated into the drivetrain. As other examples, torque limiting can be incorporated by monitoring current and thus power transmitted to the drivetrain, by a friction clutch, or by using a torque limiting device with a pawl and a spring-loaded pawl, or other torque limiting mechanisms.

[0179] Another advantage of certain embodiments of the chainsaw disclosed herein is that the chainsaw design facilitates precise bone cutting, resulting in improved, closer, or tighter fit between the bone and the implant. Precise fit better locks the implant in place, reducing the risk of displacement and promoting faster healing. This closer fit can lead to better short-term and long-term patient outcomes. For example, improved fit allows the implant to support stress more quickly. This can allow patients to walk faster after surgery while reducing the risk of damaging the implant-tissue interface. Ultimately, bone growth and integration between the implant and surrounding bone are required. The precise fit surface achievable by the embodiments disclosed herein accelerates this healing process.

[0180] Furthermore, the precise cutting achieved through the embodiments disclosed herein enables the development of implant indications that are currently untreatable. Certain embodiments of this disclosure also facilitate the development of more custom-made implants.

[0181] Figures 14A-14D Application examples of precise cutting that can be achieved using certain embodiments are shown. Figures 14A-14B An exemplary shaped implant Y for use in the vertebra is shown. Figure 14C A vertebra V with a digging volume X is shown, the digging volume X having a precise stepped shape achievable using certain embodiments of the present disclosure, for receiving... Figures 14A-14B The implant Y can be manufactured with a shape corresponding to the excavation volume X. In this example, the steps of the implant Y will lock it in place in the front-to-back direction. The boss shape of the implant Y stabilizes it in the vertical direction.

[0182] As described above, a chainsaw can create precise spaces, such as volumes X. For example, a chainsaw case 10 can be used to precisely cut such spaces. In other examples, the chain links or saw bar can be shaped to create this shaped space. The chainsaw links can have customized shapes to create suitable excavation shapes for corresponding shaped implants. For example, in a chain link with two rows of teeth, where the first row of teeth is along a first lateral side and the second row of teeth is along a second lateral side, the first row of teeth can be higher than the second row of teeth. Such a chain link can be used to excavate, for example... Figure 14C The stepped shape shown has higher rows of teeth digging wider sections and lower rows digging narrower sections. In an alternative, the link may have teeth that are higher in the middle than on the lateral sides, and these teeth may be rounded to form convex curved sides of the digging space. In another alternative, the link may have teeth that are higher along the lateral sides than in the middle to form concave curved sides of the digging space. In yet another alternative, Figure 14D A front view of a custom saw shank 99 is shown, which allows for manufacturing via a single-cutting cut. Figure 14CThe chainsaw creates a shaped bone space. Multiple chains can be driven simultaneously around the same saw bar, one along the wider portion of the bar and one along the narrower portion. The shape of the cutting profile of the chain links and / or the saw bar can be customized to the implant, allowing a single pass of the chainsaw to produce an extremely stable, repeatable, and tight fit with the implant. The saw and / or cutting profile of the chain links can be custom-designed to produce the desired form of the implant.

[0183] Improved fit between bone or other tissues and the implant helps improve patient outcomes. Implants with better fit have a lower risk of displacement and can support stress more quickly. Patients can regain mobility faster with a lower risk of damage to the tissue-implant interface.

[0184] Figures 15A-15E An example of a chainsaw 100 with a surgical handle 101 is shown. The chainsaw 100 may be similar to a chainsaw as described above. The surgical handle 101 may be attached to the saw mechanism, allowing for more precise linear lateral or transverse movement via hand movement. The surgical handle 101 may be removably attached to the saw mechanism. In the example shown, the surgical handle 101 protrudes laterally from the saw mechanism and has a protrusion that can be easily gripped by the user (surgeon). By gripping the handle 101, the surgeon can move to the left (or right) within the plane of the saw blade. Figure 15D ) or to the right ( Figure 15E The chainsaw blade moves laterally. The chainsaw blade may be able to pivot about the axis of rotation.

[0185] Figure 16 A protective device 110 is shown that can be attached to a chainsaw 100. The chainsaw 100 can be similar to a chainsaw as described above. The protective device 110 can be attached around one longitudinal side and the distal end of the chainsaw to protect the chain in those areas. In alternative embodiments, the protective device can be designed to cover more or less of the chain path, such as extending only along one longitudinal side while leaving the distal end uncovered. When only a portion of the chainsaw (such as one longitudinal side) is used for cutting, the protective device 110 can prevent unwanted cuts, such as unintentional tissue damage from the other longitudinal side of the chainsaw. The protective device 110 can be removable. The protective device 110 can also be flipped to protect the other side of the chainsaw. In the illustrated embodiment, the protective device 110 has a U-shaped base at one end. Each arm of the U-shaped base can be placed within a tubular limiter attached to the chainsaw. Double anchoring can stabilize the device. On one side, the protective device 110 extends along the length of the cutting chain.

[0186] Figures 17A-17B An example embodiment of the drivetrain mechanism of a chainsaw 120 is shown. The chainsaw bar 121 and chain link 122 can be similar to one or more chainsaw bars and chain links as described above. The housing 123 is in... Figures 17A-17BThe center is shown as transparent to show the details of the transmission mechanism.

[0187] like Figures 17A-17B As can be seen, the drive gear 124 engages with the saw gear 125 at a 90-degree angle. The drive gear 124 can be driven by a suitable drive mechanism, such as a motor as described above. The drive gear 124 and the saw gear 125 can be bevel gears that engage with each other. Rotation of the drive gear 124 causes rotation of the saw gear 125. In the illustrated example, the axis of the drive gear 124 is aligned with the axis of the saw bar 121. In an alternative embodiment, the axis of the drive gear 124 does not need to be aligned with the axis of the saw bar 121. For example, the axis of the drive gear 124 can be at a 90-degree angle to the axis of the saw bar 121.

[0188] The sawing gear 125 is securely coupled to the chain drive gear 126, such that rotation of the sawing gear 125 causes rotation of the chain drive gear 126. In this example, both the sawing gear 125 and the chain drive gear 126 are securely attached to a shaft 127 that passes through the housing 123 from one side to the other and is free to rotate relative to the housing 123. Therefore, in this example, the sawing gear 125 is securely coupled to the chain drive gear 126 via the shaft 127. In other examples, the sawing gear 125 may be directly coupled to the chain drive gear 126. The sawing gear 125 and the chain drive gear 126 may rotate about a fixed axis.

[0189] The chain drive gear tooth 126 abuts against the inner edge of the chain link 122, such that the teeth of the chain drive gear tooth 126 engage with the engagement recess of the drive gear tooth on the chain link 122. Therefore, rotation of the chain drive gear tooth 126 causes the chain to rotate. The chain drive gear tooth 126 can be similar to the drive gear tooth 72 described above.

[0190] exist Figures 17A-17B In the example, one or more fixing screws 128 can be used to stabilize the saw bar 121. Furthermore, a guard 129 can be used to cover the chain teeth on one side of the chainsaw, thereby protecting adjacent tissue from unintentional damage. The guard 129 can be similar to the guard 110 discussed above.

[0191] Figures 18A-18C Another example of the drivetrain mechanism of the chainsaw 130 is shown. The chainsaw bar 131 and chain link 132 can be similar to one or more chainsaw bars and chain links as described above. The housing 133 is in... Figures 18A-18C The center is shown as transparent to show the details of the transmission mechanism.

[0192] Figures 18A-18CAn example embodiment has a saw position drive gear 134A and a chain drive gear 134B. Each drive gear 134A, 134B meshes with saw gears 135A, 135B, respectively. Each drive gear 134A, 134B and its corresponding saw gears 135A, 135B can be bevel gears that engage with each other. Rotation of each drive gear 134A, 134B causes rotation of its corresponding saw gears 135A, 135B. In the illustrated example, the axis of each drive gear 134A, 134B is parallel to the axis of the saw bar 131. In an alternative embodiment, the axes of the drive gears 134A, 134B do not need to be parallel to the axis of the saw bar 131. For example, the axes of the drive gears 134A, 134B may be at a 90-degree angle to and offset from the axis of the saw bar 131 by 90 degrees.

[0193] Chain drive gear 134B is used to drive the chain around the saw bar and can be driven by a suitable drive mechanism, such as a motor as described above. Saw gear 135B can be securely coupled to chain drive gear teeth (not shown) such that rotation of saw gear 135B causes rotation of the chain drive gear teeth. In one example, saw gear 135B and chain drive gear teeth are securely attached to shaft 137, which passes through housing 133 from one side to the other and is freely rotatable relative to housing 133. Thus, in such an example, saw gear 135B is securely coupled to chain drive gear teeth via shaft 137. In other examples, saw gear 135B can be directly coupled to chain drive gear teeth (and the shaft may or may not rotate).

[0194] The chain drive gear teeth abut against the inner edges of a series of chain links 132, such that the teeth of the chain drive gear teeth engage with the drive gear tooth engagement recesses on the chain links 132. Therefore, rotation of the chain drive gear teeth causes the chain to rotate. The chain drive gear teeth can be similar to the drive gear teeth 72 discussed above.

[0195] The saw position drive gear 134A is used to position the saw bar and can be driven by a suitable drive mechanism, such as a motor (e.g., a stepper motor). The saw gear 135A can be securely coupled to the saw bar such that rotation of the saw gear 135A causes the saw bar to rotate about the axis of shaft 137. In one example, the saw gear 135A and the saw bar are securely attached to shaft 137, and shaft 137 rotates together with the saw bar. In another example, the saw gear 135A and the saw bar rotate about shaft 137.

[0196] By controlling the saw position drive gear 134A, the user can pivot the saw bar around the axis of shaft 137 to the desired angle. Therefore, Figures 18A-18C The drive mechanism can be used to drive the chain around the saw bar, or to pivot the saw bar.

[0197] exist Figures 18A-18CIn the example, protective device 139 can be used to cover the chain teeth on one side of the chainsaw, thereby protecting adjacent tissue from unintentional damage. Protective device 139 can be similar to protective device 110 discussed above.

[0198] Some embodiments of the invention described herein are useful for various surgical applications. One such application is minimally invasive surgery. Currently, many surgical specialties perform minimally invasive procedures. Large incisions have a high level of postoperative pain and morbidity. In minimally invasive surgery, surgeons operate through several small incisions. They insert cannulas through these incisions; the cannulas are essentially tubes that go into the body. By using specialized instruments through cannulas, surgeons can perform procedures without the disadvantages of large incisions.

[0199] Another advancement in surgery is the use of robotics during procedures. Robots can operate with greater precision in confined spaces than humans. However, some existing instruments, such as oscillating bone saws, vibrate too much to be efficiently controlled by current robotic technology. As a result, orthopedics, a specialty that could greatly benefit from precise bone cutting and shaping, is limited in its ability to utilize robotics.

[0200] There is clearly a need for a small bone saw capable of passing through cannulas with minimal vibration. Some embodiments of the chainsaw disclosed herein can pass through relatively small cannulas, such as those with an inner diameter of 10 mm or less, and can cut bone with minimal vibration.

[0201] Figure 19 An illustration shows an example mechanism 140 for controlling the movement of a chainsaw. Mechanism 140 includes a robotic arm 141, which can move in any direction within a plane perpendicular to the long axis of the chainsaw, as indicated by arrow 141A. Starting from a fixed point at its proximal end, as indicated by arrow 141B, the robotic arm 141 can tilt in any direction at various angles up to an obtuse angle. Mechanism 140 can be repositioned so that the fixed point of the robotic arm 141 is at any desired location. As indicated by arrow 141C, the robotic arm 141 can also rotate about its long axis at any angle. The robotic arm 141 can also extend and retract, as indicated by arrow 141D. A tubular extension 142 extends from the robotic arm 141. The tubular extension 142 is part of a device that enters the body. Like the robotic arm 141, the tubular extension 142 can rotate about its long axis at any angle, as indicated by arrow 142A, and can extend and retract, as indicated by arrow 142B. As indicated by arrow 143A, the saw blade 143 can pivot up to 360 degrees relative to the tubular extension 142 about the pivot axis 144. All these positions and movements can be controlled by the robot's computer. Figure 19As shown, the mobility of the robotic arm 141 allows for virtually unlimited mobility in saw placement and angle.

[0202] Figures 20A-20E An example embodiment of the chainsaw 150 is shown. Figure 20A The diagram shows a chainsaw 150 with the saw blade 151 in a horizontal position. Figure 20B The chainsaw 150 is shown with the saw blade 151 in a vertical position. Figure 20C A top view of the chainsaw 150 is shown. Figure 20D The chainsaw 150 is shown with the saw blade 151 rotated slightly to the right. Figure 20E The chainsaw 150 is shown with the saw blade 151 rotated slightly to the left.

[0203] Various methods can be used to manufacture chainsaw links according to the embodiments disclosed herein. According to this disclosure, chainsaw links (such as...) Figure 2 The chainsaw link 40 shown can be manufactured by the following process.

[0204] First, the chain links are shaped to their approximate form using metal injection molding (MIM). MIM allows for the mass production of chain links at low cost. In MIM, powdered metal and powdered plastic are mixed together (and heated) and injected into a mold. At this point, the shaped part is in a "green" state, with an approximate shape but a lower density than the final product. Through debinding and sintering processes, the part is transformed into a metal component with near-100% density.

[0205] Figure 21 A partial view of the chainsaw link 40 after the metal injection molding step is shown. While the part can be molded to have many fine features, it is difficult to obtain very sharp edges at this stage. For example... Figure 21 As shown, the front and rear cutting edges, as well as the tip, of each cutting tooth 61, 63, and 65 are rounded. Figure 21 In the examples shown, the average radius of the cutting edge is between .002 inches and .004 inches. While such a cutting edge, which is not as sharp as a razor, may be sufficient to cut bone, it may not be optimal for some applications.

[0206] Figure 22A and 22B The first lateral side 45 and the second lateral side 46 of the chainsaw link 40 are shown after shaping but before the grinding step. Grinding transforms the spherical tip and rounded edge into a ground cutting surface, resulting in sharper cutting teeth 61, 62, 63, 64 and 65.

[0207] According to this disclosure, a grinding step is performed after the chainsaw links are formed. The grinding step includes double-disc grinding. Double-disc grinding allows for a very fine surface finish, similar to a flat, planar surface. The parallelism of the lateral sides 45 and 46 of link 40 can be precisely controlled, as can the thickness of link 40. For example, link 40 can be ground to a thickness of 2 mm (.078 inches) (edge ​​to edge).

[0208] Due to the unique configuration of the pyramidal teeth in the example chainsaw link 40, which have cutting edges aligned with the lateral sides 45, 46 of link 40, double-disc grinding can sharpen and / or trim all necessary cutting edges. The combination of metal injection molding, tooth design, and double-disc grinding enables the manufacture of links with sharp teeth at an extremely low manufacturing cost.

[0209] In dual-disc grinding, the two grinding discs are spaced apart and rotate relative to each other as the chainsaw links 40 rotate or are linearly fed in the space between the discs. The chainsaw links 40 can be fed along a conveyor so that they pass continuously between the discs. One disc grinds the first lateral side 45 of the links 40, while the other disc grinds the second lateral side 46. This dual-disc grinding is a highly efficient grinding process that uses opposing grinding wheels to grind and remove equal amounts of material from both sides of the workpiece. The result is a flat surface, parallel sides, and a smooth finish. In one example, the process can produce a parallelism tolerance of .0005 inches and a finish up to 16 Ra.

[0210] Figure 23 The final sharp cutting edge and tip of the chain link after grinding are shown. An example cutting tooth 63 with a sharp cutting edge is shown.

[0211] Another advantage of certain embodiments of the chainsaw disclosed herein is the ability to use chainsaws in robotic surgery. Surgical robots are of great value in orthopedics because of their ability to produce precise incisions regardless of the surgeon's condition or skill. Current surgical robots with sagittal saws are prone to irregularities and inaccuracies due to the vibrations of the saw blade. Utilizing the embodiments disclosed herein, the reduction in vibration, the smaller size of the saw blade, the reduced cutting force, minimal deviation from the intended cutting path (no scraping), reduced inaccuracies, and / or minimal heat generation make chainsaws particularly suitable for use in robotic systems. This is especially true for surgical applications requiring precise bone cutting.

[0212] Furthermore, the sagittal saw is not designed to remove soft tissue (e.g., ligaments). Therefore, if soft tissue is introduced into the cutting zone, the saw must be removed, and the soft tissue must be manually cut using conventional surgical instruments. The bidirectional capability of some embodiments of this disclosure with asymmetric cutting elements allows for cutting bone in one direction and soft tissue in another. Thus, robotic control of the saw can continue during bone and soft tissue cutting without having to remove the robotic saw.

[0213] Robotic control mechanisms, such as robotic arms driven by gear mechanisms, cams, electromechanical, pneumatic, hydraulic, biofluidic, or any combination or arrangement thereof, can be applied to guide the saw. In some embodiments, the robotic control automatically corrects for bias in the direction opposite to the direction of travel of the chain links. The force required to counteract the bias can be calculated using calculations of the amount of power transmitted to the saw. Resistance can also be calculated using inputs from other systems, such as optical systems like laser systems or 3D vision systems, ultrasonic systems, Hall sensors, or sonar systems.

[0214] In some embodiments according to this disclosure, the robotic system includes at least one arm mechanically connected at one end to a patient's bone. The other end of the arm may be mechanically connected to an instrument, a robotic arm, or a computerized robotic unit including a robotic arm.

[0215] An arm attached to or connected to the patient's bone can carry or be configured to carry instruments such as bone saws and / or cutting guides for bone saws. For example, an arm attached to or connected to the patient's bone can carry or be configured to carry chainsaws as disclosed herein and / or cutting guides for chainsaws as disclosed herein. Furthermore, in some embodiments, other types of saws, such as sagittal saws, can be used. In other embodiments, the arm attached to or connected to the patient's bone can carry non-cutting instruments, including but not limited to scanning probes, temperature probes, drug delivery systems or devices, or other instruments.

[0216] The arm of the robotic system disclosed herein can be anchored to the patient's bone via a suitable support base that can be secured to the patient's bone. Support bases for bone are known, such as for cutting guides. Other examples of support bases that can be secured to a patient's bone are shown and described in U.S. Provisional Patent Application No. 63 / 195,994, filed June 2, 2021, entitled "Cutting Guide System and Method". That patent application discloses support bases suitable for securing to, for example, the patient's tibia and / or femur.

[0217] The arm anchored to the patient's bone can be adjusted in six degrees of freedom: positioning along the xyz axes and rotational orientation relative to the xyx axes. The arm may include one or more arm segments and / or one or more joints. Joints can connect arm segments to a support base, connect arm segments to adjacent arm segments, and / or connect arm segments to an instrument, robotic arm, or robotic unit. Joints can have any suitable structure that allows adjustment of the arm, thereby adjusting the arm's positioning and / or rotational orientation relative to the bone. Example joints include ball-and-socket joints, rotational joints, and hinge joints.

[0218] In some embodiments, the arm attached to the patient's bone may have a feedback system, whereby positional and / or rotational orientation information can be transmitted to a control system. For example, the joint and / or arm segment may have sensors for reading positional and / or rotational orientation information and a connection (wireless or wired) for transmitting such information to the control system. Thus, the device provides a telemetry stream that updates the robotic system with respect to the position and rotational orientation of the resected bone. In this way, the position and / or rotational orientation of the bone relative to the robotic arm and / or instrument can be continuously monitored and known. The position and / or rotational orientation of the robotic arm and / or instrument can be automatically adjusted based on the position and / or rotational orientation of the bone, as determined by the feedback system.

[0219] In some embodiments, the arm attached to the patient's bone may have one or more actuators, such as electromagnetic actuators (e.g., one or more stepper motors, servo motors, or other actuators), for moving the arm to a desired position. The actuators may adjust the position and / or rotational orientation of the arm. The actuators may move the arm at high or low speeds, may maintain the instrument's position relative to the bone, and may be combined with braking to lock the position if real-time repositioning is not required.

[0220] In embodiments where an arm connected to the patient's bone is attached to an instrument at its other end, adjusting the position and / or rotational orientation of the bone-connected arm can, in turn, adjust the position and / or rotational orientation of the instrument. Similarly, in embodiments where the arm is directly attached to a robotic arm (as opposed to a floor-mounted robotic unit including a robotic arm), actuators can be used to adjust the bone-connected arm to adjust the position and / or rotational orientation of the robotic arm. This, in turn, can adjust the position and / or rotational orientation of the instrument carried by the robotic arm.

[0221] In some example embodiments, the arm is connected at one end to a support base fixed to the patient's bone and at the other end to a computerized robotic unit including a robotic arm. The computerized robotic unit can be mounted on the operating room floor. The bone-connected arm can be similar to the arm described above. As the patient's bone moves relative to the robotic unit, and thus relative to the robotic arm of the robotic unit, the bone-connected arm provides feedback to the robotic unit's control system regarding the position and / or orientation of the patient's bone relative to the robotic unit and thus relative to the robotic arm. The control system can then control the robotic arm and any instruments carried by the robotic arm based on the position and / or orientation of the patient's bone.

[0222] In some embodiments, the arms described above may be attached to the patient's femur and / or tibia. Separate arms may be attached, one to the patient's femur and the other to the patient's tibia, whereby both arms are associated with the control system. The femoral and tibial arms may be used together for range of motion feedback, thereby positioning the knee joint in all planes and axes.

[0223] In some embodiments, one or more arms, as described herein, may be anchored to the patient's bone at one or more locations. For example, in one embodiment for attachment to the patient's femur, a first arm is anchored to the medial epicondyle, and a second arm is attached to the lateral epicondyle. The other ends of both arms may be connected to an instrument or a robotic arm carrying the instrument. For example, the instrument or robotic arm may be mounted between the two bone-connected arms. The attachment points of the bone-connected arms and the instrument or robotic arm may form an axis about which the instrument or robotic arm can rotate. The attachment points of the bone-connected arms and the two epicondyles may form an axis between them, about which the structure (the two bone-connected arms and the instrument or robotic arm) can rotate. This can position the robotic arm or instrument for various desired cutting of the femur. The entire assembly may be movable by actuators as described above to move the robotic arm or instrument to various desired locations.

[0224] In some embodiments, the instrument or robotic arm carrying the instrument is directly attached to one or more arms, which in turn are attached to the patient's bones (e.g., the arms attached to the medial and lateral epicondyles as described above). The instrument or robotic arm can be supported by the bone-connected arms, eliminating the need for floor-mounted robotic units used in prior art systems. Devices in such examples can be specifically mounted on the patient and thus can move with the patient's movements.

[0225] Figure 24An example of a robotic system 160 for surgical use is shown, comprising an arm 162 attached to a bone (such as the femur F) of a patient. Arm 162 may be additionally or alternatively attached to the tibia T. In the illustrated embodiment, a first end of arm 162 is attached to bone F at joint 163, thereby allowing movement in all directions and rotational orientations. Arm 162 includes a series of arm segments 164, 166, and 168. Arm segment 164 is connected to arm segment 166 via joint 165, thereby allowing relative movement between them. Arm segment 166 is connected to arm segment 168 via joint 167, thereby allowing relative movement between them. A second end of arm 162 is attached to a robotic arm 170 at joint 169, thereby allowing relative movement between the bone-connected arm 162 and the robotic arm 170. Robotic arm 170 carries an instrument 172 (e.g., a bone saw, bone saw guide, or other instrument). Robotic arm 170 may be part of a robotic unit 174, which may include a base unit 175 on an operating room floor 176. In an alternative embodiment, the second end of arm 162 can be directly connected to instrument 172, without an intermediate robotic arm 170, so that arm 162 serves as a robotic arm for controlling the positioning of instrument 172. In another alternative embodiment, robotic arm 170 is not part of a floor-mounted robotic unit, but is entirely supported by arm 162. Therefore, the structure below point 178 on robotic arm 170 can be omitted (the electronics of base unit 175 can be incorporated into robotic arm 170).

[0226] The arm 162, connected to the patient's bone, may have a feedback system whereby position and / or rotational orientation information can be transmitted to the control system of the robotic system 160. For example, joints 163, 165, 167, 169 and / or arm segments 164, 166, 167 may have transducers for reading position and / or rotational orientation information and connections (wireless or wired) for transmitting such information to the control system. The control system can use this information to adjust the position of the arm 162, the robotic arm 170, and / or the instrument 172. In some embodiments, the arm 162, connected to the patient's bone, may have one or more actuators, such as electromagnetic actuators (e.g., one or more stepper motors, servo motors, or other actuators), for moving the arm 162 to a desired position.

[0227] Figure 25Another example of a robotic system 180 for surgical use is shown, comprising multiple arms 182, 184, 186, 188 connected to a bone (such as the femur F) of a patient. A first end of each arm 182, 184, 186, 188 is connected to the bone at joint 181, allowing movement in all directions and rotational orientations. Each arm 182, 184, 186, 188 may include multiple arm segments joined together via one or more joints, allowing relative movement between them. A second end of each arm 182, 184, 186 is connected to a robotic arm 170A at joint 183, allowing relative movement between them. A second end of arm 188 is connected to arm 182 and, through arm 182, to robotic arm 170A. A second end of arm 188 is connected to arm 182 at joint 185, allowing relative movement between them. Robotic arm 170A carries instrument 172A. In the illustrated embodiment, robotic arm 170A is not part of a robotic unit mounted on the floor, but is fully supported by arms 182, 184, 186, and 188. In an alternative embodiment, robotic arm 170A may be part of a robotic unit that can be located on the operating room floor. In yet another alternative embodiment, the second ends of arms 182, 184, and 186 may be directly connected to instrument 172A, such that arms 182, 184, 186, and 188 serve as robotic arms for controlling the positioning of instrument 172A.

[0228] Arms 182, 184, 186, and / or 188, connected to the patient's bone, may have a feedback system whereby position and / or rotational orientation information can be transmitted to the control system of the robotic system 180. For example, joints and / or arm segments may have transducers for reading position and / or rotational orientation information and connections (wireless or wired) for transmitting such information to the control system. The control system can use this information to adjust the position of arms 182, 184, 186, 188, robotic arm 170A, and / or instrument 172A. In some embodiments, arms 182, 184, 186, and 188, connected to the patient's bone, may have one or more actuators, such as electromagnetic actuators (e.g., one or more stepper motors, servo motors, or other actuators), for moving arms 182, 184, 186, and / or 188 to a desired position.

[0229] Similar to Figure 25 The robotic system according to this disclosure can have arms connected to other arms, thus forming a branch system between the bone and the robotic arm carrying the instrument or the instrument. This can contribute to the stability and precise positioning of the device.

[0230] The apparatus disclosed herein can achieve one or more advantages. For example, some embodiments described herein can provide more direct feedback on the position and / or orientation of the patient's bones (e.g., femur and / or tibia) compared to currently used optical systems. Some embodiments disclosed herein can also have less latency between patient movement and robotic arm response, thus resulting in smoother and safer control of the saw blade or other instruments. Some embodiments disclosed herein can be far more accurate with much less equipment and software, especially because the apparatus disclosed herein does not require the computer processing power needed for stereo positioning systems that use stereo cameras and convert images into position and rotational orientation information. Some embodiments disclosed herein can be cheaper and / or simpler than existing systems and can occupy less space. Some embodiments disclosed herein can keep attachments and saw space very close to the robot's structural components, inherently resulting in stability, accuracy, and reliability.

[0231] In some embodiments, the mechanical connection between the instrument or robotic arm and the bone via a bone-connected arm (and, in some embodiments, a robotic unit) results in greater stability during surgery. In other words, in the example of knee surgery, the system can stabilize the patient's knee joint subjected to cutting motions.

[0232] In summary, certain embodiments disclosed herein can achieve one or more advantages, such as lower cost, easier use, fewer failures, more precise cutting, shorter operation time, shorter recovery time and / or better results.

[0233] In other variations of robots or automated systems (with or without the skeletal connection described above), the saw (e.g., a chainsaw) can be connected to a feedback system that measures one or more of a variety of conditions during bone cutting (e.g., cutting forces or other forces, rotational forces, various forces resisting the chain links, forces resisting the rods, forces resisting the drive pins, forces within the gears, vibration levels, pitch and volume of noise, and / or the amount of deviation from the ideal plane). These measurements are then analyzed by software to provide intelligent control over the saw, the drive, and / or the robot.

[0234] For example, bone is heterogeneous, possessing varying degrees of density, hardness, and dryness. Saws differ in their performance on different types of bone in terms of speed, vibration, noise (pitch and volume), and ability to maintain a flat surface. Bone saws need to be able to safely cut bone without endangering the surrounding soft tissue.

[0235] As an example of using a feedback system, based on measurements, the cutting system can determine whether the saw is being used against hard bone, cartilage, or soft tissue. When the saw cuts through soft cancellous bone and encounters hard cortical bone, the control system identifies the harder bone and can determine whether the saw is approaching or engaging the edge of bone in the cutting zone, outside of which is fragile soft tissue, such as the medical cruciate ligament, and on the other side is the transverse cruciate ligament. Based on measurements and software analysis, the control system can control the saw speed to cut faster or slower and / or move to an oscillating mode to protect soft tissue. The control system can stop the saw immediately upon cutting through bone before it damages any soft tissue (recognizing a significant reduction in resistance to the saw).

[0236] Figure 26 This is a flowchart of an example method for the automated control of a saw. An example automated system for surgical applications includes: a saw, such as a chainsaw for cutting bone; a feedback system that measures one or more conditions of the chainsaw while it is operating; and a control system that receives information from the feedback system and automatically changes the input to the chainsaw based on that feedback to alter the operation of the chainsaw. In a first step 191, the saw is operated based on operating parameters sent to it. In a second step 192, the feedback system measures one or more conditions of the saw while it is operating. For example, as described above, the feedback system may measure one or more forces or other conditions, such as vibration, noise, and / or deflection. The feedback system sends these signals to the control system. In a third step 193, the control system receives information from the feedback system and automatically changes the input to the saw based on that feedback to alter the operation of the saw. For example, the control system may change the input to the saw to change its speed or mode of movement or direction (e.g., reverse the chain and / or switch between unidirectional and oscillating modes). Inputs from the control system based on information from the feedback system are as follows: Figure 26 As shown by line 194. This process can be repeated continuously or as needed to automatically update the saw's operation based on feedback.

[0237] In addition to cutting bone for implants, such as knee implants, spinal implants, and other implants, the chainsaw embodiments disclosed herein can be used in other surgeries involving bone or tissue cutting. For example, the chainsaw embodiments disclosed herein can be used to cut bone to connect bones, correct conditions, or for other purposes. Therefore, the use of chainsaws as disclosed herein is not limited to total knee or total implant arthroplasty. The use of chainsaws as disclosed herein is not limited to use with a guiding system. Chainsaws as disclosed herein can be used in many surgeries where precise cutting of bone or tissue is advantageous.

[0238] As an example, embodiments of the chainsaw disclosed herein can be used for spinal fusion. The chainsaw can be used to make parallel cuts into adjacent vertebral bodies, remove the intervertebral discs between them, and connect two flat planes of natural human bone. Precise cutting produces a very stable joint where the paired bones have the opportunity to migrate and deform into a single, unified bone. Embodiments of the chainsaw disclosed herein can also be used to remove bone that may contain diseases such as tumors or other deformities. An example of this is foot or toe conditions such as hammer toe, where the big toe points towards the midline of the foot, a condition that may be caused by wearing high heels. Embodiments of the chainsaw disclosed herein can be used to make one or more cuts to realign the toes to a more natural position.

[0239] The advantages of certain embodiments of the chainsaw disclosed herein over prior art oscillating sagittal saws include continuous operation of the cutting teeth without reversing direction and the ability to operate the cutting teeth through the surface to be cut in a linear direction. Prior art bone-cutting sagittal saws typically oscillate at a small angle about a pivot axis, causing the saw's cutting surface to move back and forth against the bone in an arc. In contrast, for embodiments of the chainsaw disclosed herein, the chain links can move continuously about the saw shank without reversing direction and can move linearly along the longitudinal side of the saw shank. For example, by cutting or other cutting, the chain can operate continuously about the saw shank without reciprocating movement, presenting a continuous non-reciprocating cutting motion on the longitudinal side and distal end of the saw shank. Furthermore, when the longitudinal side of the chainsaw is against the surface to be cut, the chain links and their cutting teeth can operate continuously in a linear direction across the surface being cut. When the cutting element has a cutting edge that facilitates slicing bone or other tissue, such as the pyramidal teeth described above, the chainsaw achieves continuous slicing action through bone or other tissue. Compared to existing saws, the ability to combine continuous cutting action with cutting teeth of the shape described herein without reversing direction and / or along a straight direction to achieve continuous slicing action offers unique advantages as the primary cutting method.

[0240] Another advantage of certain embodiments of the chainsaw disclosed herein is the ability to operate the chainsaw at low speeds. In some embodiments, the chainsaw can operate at low speeds even on inclined or irregular surfaces, while still creating bite or edge or footing in the bone. This is a significant advantage over current sagittal saws, which in virtually all cases must operate at high speeds to begin cutting.

[0241] Another advantage of certain embodiments of the chainsaw disclosed herein is that miniaturization can be achieved using the disclosed design, thereby facilitating use in certain surgical applications. The design of the saw shank and chain links results in a chainsaw that can be manufactured in a sufficiently small size for safe, reliable, and efficient operation.

[0242] Many variations of the above embodiments are possible while still retaining one or more features of this disclosure. For example, links in a single chain can take on different shapes. For instance, a first type of link may have hooks at both ends, a second type of link may have recesses at both ends, and the first type of link may alternate with the second type of link in the chain. The components of the chainsaw (including the links and the saw blade) can be made of any suitable material, including metals (e.g., stainless steel), plastics, composite materials, ceramics, carbon, or carbon fiber materials. Some of these materials (e.g., biocompatible ceramics) can reduce debris and heat, and can minimize wear.

[0243] The inventions disclosed herein can be implemented together or separately. For example, a chainsaw with links can be used with different saw blades (such as those with links). Figure 11B The channel or trench shown does not have the following characteristics: Figures 5A-5C The saw bar of the track shown is used together, the links having cutting teeth with the features disclosed herein (such as a pyramidal shape and / or an arrangement in rows along the lateral side). As another example, such as Figures 5A-5C The saw bar with a track can be used with a chain link having grooves as disclosed herein but with cutting teeth different from those disclosed herein.

[0244] Those skilled in the art will appreciate that the embodiments covered by this disclosure are not limited to the specific exemplary embodiments described above. While illustrative embodiments have been shown and described, extensive modifications, alterations, and substitutions are contemplated in the foregoing disclosure. It should be understood that such changes may be made to the foregoing without departing from the scope of this disclosure. Therefore, it is appropriate that the appended claims be interpreted broadly and in a manner consistent with this disclosure.

Claims

1. A chainsaw, comprising: A saw bar having a first longitudinal side, a second longitudinal side, and a distal end, wherein the first longitudinal side, the second longitudinal side, and the distal end define at least a portion of a chain path surrounding the saw bar; and Multiple chain links are arranged in a chain along a chain path surrounding the saw bar; The saw bar includes a body and a track extending from the body along at least a portion of a chain path surrounding the saw bar; The saw bar body includes a first boss extending beyond a first side of the track and a second boss extending beyond a second side of the track; The chain includes grooves such that it spans the track of the saw bar; and Wherein, along at least the cut portion of the chain path, the bottom surface of the chain contacts a first boss of the saw body on a first side of the track, the bottom surface of the chain contacts a second boss of the saw body on a second side of the track, and the chain does not contact the top of the track, thereby leaving a gap between the chain and the top of the track, such that along at least the cut portion of the chain path, the force on the chain link is transmitted to the bosses of the saw on both sides of the track.

2. The chainsaw according to claim 1, wherein, The track of the saw bar includes a protrusion, and the groove of the chain includes a notch for receiving the protrusion, wherein the protrusion restricts the chain link from misaligning in a direction away from the saw bar.

3. The chainsaw according to claim 1, wherein, The first link includes a hook that engages a recess of the second link, thereby connecting the first link and the second link and allowing the first link and the second link to be hinged to each other without separating when the chain is driven around the saw bar; and At least one link includes one or more cutting teeth, which are oriented such that the cutting action of the link generates a force perpendicular to the chain path and pointing towards the saw bar.

4. The chainsaw according to claim 1, wherein, The first link includes a hook that engages a recess in the second link, thereby connecting the first and second links and allowing the first and second links to hinge together without separating when the chain is driven around the saw bar; and At least one link includes a cutting tooth in the shape of a cone or pyramid.

5. The chainsaw according to claim 4, wherein, The cutting teeth are in the shape of an oblique pyramid.

6. The chainsaw according to claim 4, wherein, The tip of the cutting tooth is aligned with the lateral side of the at least one link.

7. The chainsaw according to claim 4, wherein, The at least one link includes a plurality of pyramidal cutting teeth.

8. The chainsaw according to claim 4, wherein, The at least one link includes a first row of pyramidal cutting teeth along a first lateral side of the at least one link and a second row of pyramidal cutting teeth along a second lateral side of the at least one link.

9. The chainsaw according to claim 8, wherein, The cutting teeth along the first transverse side of the at least one link are staggered relative to the cutting teeth along the second transverse side of the at least one link, such that the tooth tips along the first transverse side are aligned with the valleys along the second transverse side.

10. The chainsaw according to claim 8, wherein, The first link has a first pyramidal cutting tooth with a first profile, and a second pyramidal cutting tooth with a second profile at the edge of the first link, the second profile being half the size of the first profile, and the second link adjacent to the first link has a third pyramidal cutting tooth, the profile of which is half the size of the first profile, wherein, when the chain is assembled on the saw bar, the third pyramidal cutting tooth of the second link is adjacent to the second pyramidal cutting tooth of the first link.

11. The chainsaw according to claim 1, wherein, The saw bar includes a contact surface; Each of the plurality of links includes a contact surface; The plurality of chain links are arranged around the saw bar such that when the chain is driven around the saw bar, the contact surfaces of the chain links slide against the contact surfaces of the saw bar; and The chainsaw also includes a hard coating applied to the contact surface of the saw bar or the contact surface of the chain link.

12. The chainsaw according to claim 11, wherein, The hard coating is a diamond coating.

13. The chainsaw according to claim 1, further comprising: A protective element is provided to prevent the chainsaw shank and chain links from contacting the cutting block as the chainsaw passes through it.

14. The chainsaw according to claim 13, wherein, The protective element includes: a first guide post adjacent to the chain and spaced apart from the chain along a first longitudinal side of the saw bar; and a second guide post adjacent to the chain and spaced apart from the chain along a second longitudinal side of the saw bar; The first and second guide posts are wider than the chain.

15. The chainsaw according to claim 14, wherein, The first and second guide posts are retractable.

16. The chainsaw according to claim 13, wherein, The protective element includes a retractable cover.

17. An automated system for surgical applications, comprising: A chainsaw according to any one of claims 1-16, used for cutting bone; A feedback system that measures one or more conditions of the chainsaw during its operation; and A control system that receives information from the feedback system and automatically changes the input to the chainsaw based on the information to alter the chainsaw's operation.

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