Orthopedic pin for optical analysis of bone regions

Abstract

An orthopedic pin for use in optical analysis of a bone region. An optical fiber arrangement extends within an elongate shaft from a distal end to a proximal end. A coupling is provided at an intermediate location along the shaft, and the optical fiber arrangement includes a first portion on one side of the coupling and a second portion on the other side of the coupling. The coupling allows relative rotation between portions of the shaft on opposite sides of the coupling while maintaining optical coupling between the first and second portions of the optical fiber.

Description

Technical Field

[0001] This invention relates to an orthotic pin for optical analysis of bone regions. Related surgical tools and kits are also disclosed. The invention has applications in the general field of orthopedic surgery, and more specifically in the field of spinal surgery. In the latter, the orthotic pin can, for example, be used to guide the placement of pedicle screws. Background Technology

[0002] In many medical procedures, implantable devices are inserted into bone tissue. For example, bone fixation devices are often used to position bone tissue relative to other bone tissue or relative to the external environment.

[0003] Examples of such medical procedures include inserting pedicle screws in the cervical, thoracic, and lumbar spine; fixing fractures in various bone traumas; and plate positioning in hip and knee replacement surgeries.

[0004] As described by Mobbs, RJ, Sivabalan, P., and Li, J., in their article “Technique, challenges and indications for percutaneous pedicle screw fixation” (Journal of Clinical Neuroscience, 18 (2011), pp. 741-749), pedicle screw fixation is a leading method for treating degenerative spinal diseases, intervertebral disc diseases, spinal trauma, and spinal deformities. Pedicle screw fixation provides short, rigid segmental stability, preserving the motion segment and stabilizing the spine. Fusion rates and clinical outcomes for thoracolumbar fractures appear to be superior to those using other forms of treatment. According to a report from the American Health Care Research and Quality (AHRQ), approximately 488,000 spinal fusion surgeries were performed during hospitalizations in the United States in 2011 (15.7 per 10,000 patients), representing 3.1% of all operating room procedures.

[0005] Despite its global use to enhance spinal stability, the safety and effectiveness of pedicle screw devices have been questioned. A major issue is the accuracy of pedicle screw placement. Pedicle screws are often inserted blindly or under typically poor fluoroscopic guidance, leaving significant room for improvement.

[0006] In this regard, document WO 2017 / 055144 A1 describes a system for implanting an implantable device into bone tissue, a processing unit for such a system, a method for implanting the implantable device, and a method for providing information for implanting the implantable device. Given that the fat content in cancellous bone is found to be higher than that in compact bone, the lipid fraction (which can be determined by optical means, such as spectroscopy) can be used to determine the correct screw placement in healthy bone. In one embodiment, document WO 2017 / 055144 A1 describes a pedicle screw with a hollow shaft, and an optical probe can be inserted into the pedicle screw. The optical probe extends to the distal end of the screw and includes an optical fiber for optical measurements at the distal end of the screw. The fat content of the tissue anterior to the screw tip is determined by spectral analysis and used to determine whether the tissue is a (softer) or (harder) portion of bone to aid in screw placement. Document WO 2017 / 055144A1 also discloses that in operations involving the initial placement of a K-wire in bone, the optical sensing component can be integrated into the Kirschner wire, i.e., the K-wire.

[0007] In current solutions, the screwdriver and the spectral tissue sensing system are separate devices. Therefore, coupling is required between the two, which is not optimal. In most practical pedicle screw placement surgeries, a Kirschner wire is first inserted into the vertebral body, and in a second step, a hollow pedicle screw is inserted (dorsal-loaded) onto the Kirschner wire. Typically, a mechanical rotational placement tool (e.g., a hollow drill) is used to place the Kirschner wire. Since smart Kirschner wires are equipped with one or more optical fibers that need to be connected to a control unit (Optical Spectral Unit; OSU), which emits and receives reflected light and processes it, the challenge is how to connect this OSU to the Kirschner wire while still allowing the Kirschner wire to rotate freely.

[0008] Furthermore, a modular approach is preferred when using different tools, allowing much of the screw placement system to be reused, meaning that portions of the cable can be reattached to another tool of the screw placement system.

[0009] Therefore, there is a need for improved surgical tool systems. Summary of the Invention

[0010] This invention is defined by the claims.

[0011] This invention provides an orthotic pin for optical analysis of bone regions, the orthotic pin comprising:

[0012] A slender shaft having a distal end for insertion into bone and a proximal end for connection to an analysis unit;

[0013] An optical fiber device extending from the distal end to the proximal end of the elongated shaft, for transmitting optical radiation from the analysis unit to the bone region when the distal end is inserted into the bone region, and for transmitting reflected optical radiation from the bone region to the analysis unit; and

[0014] The mechanical and optical coupling element is located at the midpoint along the shaft.

[0015] The fiber optic device includes a first part located on one side of the coupler and a second part located on the other side of the coupler. Each part is used to transmit transmitted optical radiation and reflected optical radiation.

[0016] The coupling allows relative rotation between the portions of the shaft located on opposite sides of the coupling and relative rotation between the portions of the fiber optic device located on opposite sides of the coupling, while maintaining optical coupling between the first and second portions of the fiber optic device.

[0017] In other words, the coupler allows relative rotation between the opposite sides of the shaft located on the coupler, and allows relative rotation between the opposite sides of the fiber optic assembly located on the coupler, while maintaining optical coupling between the first and second parts of the fiber optic assembly. The term "fiber optic assembly" is intended to encompass any elongated optical waveguide system, and any optical transmission structure from one location to another. Therefore, the term fiber optic should be understood to refer to any suitable optical waveguide, where an optical waveguide is any physical structure that guides electromagnetic waves within a spectrum. Common types of fiber optic assemblies include, but are not limited to, optical fibers and transparent dielectric waveguides made of plastic and glass. Fiber optic assemblies and optical waveguides can have many geometries or shapes, such as planes, strips, or beams (e.g., cylindrical).

[0018] The term "optical" is intended to cover at least the wavelength range of 300 nm to 2500 nm. In one embodiment, it covers the wavelength range of 400 nm to 1600 nm. A preferred range is 1000 nm to 1600 nm. This is advantageous for bone type detection because strong fatty absorption occurs around 1200 nm, which can help distinguish between cancellous bone (fatty) and cortical bone (non-fatty). Optical may refer only to the visible light spectrum, with or without the UV spectrum. This orthotic pin allows rotation of one fiber optic section relative to another. In this way, the distal section can rotate, for example, during the insertion of the shaft into the bone by drilling, screwing, or (rotary) hammering, while the other fiber optic sections remain fixed in rotation, for example, relative to the analysis unit. This simplifies the required connection between the shaft and the analysis unit.

[0019] The coupling element preferably enables detachable coupling between the first and second parts. In this way, the distal portion of the shaft can be manipulated and used independently in a conventional manner, such as as a Kirschner wire, without utilizing the fiber optic function.

[0020] For example, the proximal end of the orthotic pin can be slidably received within a channel of a surgical device, such as a bone drill, surgical hammer, or bone fixation device, such as a pedicle screw, without altering the surgical device. For instance, in the first stage of a pedicle screw insertion procedure, a guide hole can be provided in the bone region by hammering the orthotic pin into the bone region using a surgical hammer. In the second stage of the pedicle screw insertion procedure, the pedicle screw can slide on the distal end of the orthotic pin, which serves as a guide. In the first stage, the orthotic pin is received within a channel of the surgical hammer, and during its insertion, the bone region is optically analyzed via an optical system coupled to the orthotic pin.

[0021] For example, the proximal end of the fiber optic device is configured for non-rotational coupling with the analysis unit. This not only simplifies the connection but also allows the analysis unit to be located further away, such as outside the physician's work area.

[0022] The coupling element can have a set of discrete angular orientations between opposite sides. This enables accurate alignment between the fiber ends.

[0023] The fiber optic device may include a first fiber optic assembly for optical transmission from the optical analysis unit to a remote end and a second fiber optic assembly for optical transmission from the remote end of the elongated shaft to the optical analysis unit.

[0024] Therefore, different paths are provided for the emitted interrogation light and the reflected detection light.

[0025] In the first set of examples, one of the first and second fiber optic assemblies extends along the central axis of the elongated shaft, while the other of the first and second fiber optic assemblies extends offset relative to the central axis. Therefore, a concentric arrangement of the optical fibers exists.

[0026] The other of the first and second fiber optic assemblies may include a single fiber located on one side of the coupler and a loop formed by multiple fibers located on the other side of the coupler. Therefore, different rotational positions will align the single fiber with a fiber from the loop.

[0027] In another set of examples, the optical fiber device includes a dual-core optical fiber comprising a central core and an outer core, wherein one of the central core and the outer core is used for optical transmission from the optical analysis unit to a remote end, and the other of the central core and the outer core is used for optical transmission from the remote end of the elongated shaft to the optical analysis unit.

[0028] When using dual-core fiber, this limits the possibility of another concentric arrangement. Several options exist for using dual-core fiber.

[0029] One option is to have a dual-core fiber on one side of the coupler and a loop formed by the fiber on the other side of the optical coupler.

[0030] Another option is to have a dual-core fiber on one side of the coupler and a single non-central fiber on the other side of the optical coupler.

[0031] Another option is to have dual-core optical fibers on each side of the coupler.

[0032] For these concentric arrangements, the fiber optic device may include:

[0033] An external optical fiber device located on one side of the coupler, comprising one or more non-central optical fibers or an outer core of a dual-core optical fiber.

[0034] The central optical fiber located on the other side of the coupler; and

[0035] A lens is used to focus light from an external fiber optic device onto a central fiber optic cable.

[0036] The central optical fiber then serves as a bidirectional optical signal conductor. An optical fiber splitter can then be installed to separate the two signals.

[0037] The present invention also provides a surgical tool, comprising:

[0038] As defined above, orthotic pins; and

[0039] An optical analysis unit, which is used to connect to the proximal end of a slender shaft.

[0040] For example, an optical analysis unit includes a light source and an optical detector coupled to an optical fiber device.

[0041] In one example, the optical analysis unit includes a spectrometer with an optical detector and a processor, wherein a light source is used to generate optical radiation that illuminates the bone region via an optical fiber device, and the optical radiation reflected or scattered by the bone region is optically coupled to the optical detector via the optical fiber device.

[0042] The processor is configured as follows:

[0043] This causes the light source to generate optical radiation for optical irradiation of the bone region;

[0044] Receive an electrical signal generated by at least one optical detector in response to optical irradiation of a bone region; process the received electrical signal using an algorithm configured to:

[0045] Based on the received electrical signal, determine at least a first parameter indicating the fat or water content within the indicated bone region; and

[0046] The type of bone region is identified based on at least the first parameter; the type is at least one of cancellous bone and cortical bone.

[0047] Surgical tools may also include:

[0048] Pedicle screws having a central channel for receiving a slender shaft; and

[0049] A hollow drill having a channel configured to receive a corrective pin; and / or

[0050] A surgical screwdriver having a channel configured to receive an orthotic pin; and / or

[0051] A surgical hammer, which has a channel configured to receive an orthotic pin.

[0052] According to another embodiment, the use of pins and / or surgical instruments in an interventional method in which the pins are inserted into the body of a subject is disclosed. Attached Figure Description

[0053] To better understand the invention and to more clearly illustrate how it can be practiced, reference is now made to the accompanying drawings by way of example only, wherein:

[0054] Figure 1 A handheld surgical tool in the form of an analysis unit including an optical adapter, a spectrometer, and a processor is shown;

[0055] Figure 2 A kit including an orthotic pin received within the channel of a pedicle screw is shown;

[0056] Figure 3 Another kit is shown, including an orthotic pin received within the channel of a surgical hammer;

[0057] Figure 4 A modification of the orthotic pin according to the present invention is shown;

[0058] Figure 5 The first pair of examples is shown in more detail;

[0059] Figure 6 Another set of examples using one or more dual-core optical fibers is shown;

[0060] Figure 7 Another set of examples using lenses is shown; and

[0061] Figure 8 A method that can be executed by the processor of the analysis unit is shown. Detailed Implementation

[0062] The invention will be described with reference to the accompanying drawings.

[0063] It should be understood that the detailed descriptions and specific examples provided are for illustrative purposes only when referring to exemplary embodiments of the devices, systems, and methods, and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the devices, systems, and methods of the present invention will be better understood from the following description, the appended claims, and the accompanying drawings. It should be understood that these drawings are schematic only and not drawn to scale. It should also be understood that the same reference numerals are used throughout the drawings to denote the same or similar parts.

[0064] This invention provides an orthopedic pin for optical analysis of bone regions. An optical fiber assembly extends from a distal end to a proximal end within an elongated shaft. A coupling element is provided at a midpoint along the shaft, and the optical fiber assembly includes a first portion located on one side of the coupling element and a second portion located on the opposite side of the coupling element. The coupling element allows relative rotation between the opposite portions of the shaft located on the coupling element while maintaining optical coupling between the first and second portions of the optical fiber.

[0065] To illustrate the principles of the invention, specific reference is made to medical procedures involving the insertion of bone fixation devices in the form of pedicle screws to describe the orthopedic pin. Reference is made to a specific type of orthopedic pin, resembling a Kirschner wire, commonly used in spinal surgery to facilitate the insertion of pedicle screws via hammering and subsequent guidance, through a channel slidably received within a hollow pedicle screw.

[0066] However, it should be understood that, in addition to the insertion of bone fixation devices, the present invention can also be applied to other medical procedures, including, for example, the insertion of conventional bone implantable devices. The term "orthopedic pin" generally refers to an elongated device used to fix bone elements or guide surgical instruments used in spinal or orthopedic surgery. Therefore, the present invention is also applicable to other types of orthopedic pins besides Kirschner wires, including but not limited to Steinmann pins and cannulas.

[0067] Furthermore, it should be understood that orthotic pins are commonly used to guide the insertion of surgical devices into bone, including but not limited to surgical instruments such as surgical drills, surgical hammers, screwdrivers, expanders, and awls, as well as other bone fixation devices besides pedicle screws, such as conventional bone screws. Therefore, it is conceivable that orthotic pins can generally be used to guide the insertion of medical devices into common bone regions, and their application is not limited to interventional surgical procedures involving the spine.

[0068] Before describing the features according to the invention, reference will first be made to Figures 1 to 3 To explain the intended use of orthotic pins.

[0069] As described by Mobbs, RJ, Sivabalan, P., and Li, J. in their paper entitled “Technique, challenges and indications for percutaneous pedicle screw fixation” (Journal of Clinical Neuroscience, 18(2011), pp. 741-749), a procedure for percutaneous pedicle screw insertion includes the following steps:

[0070] (i) Place the intraoperative image intensifier in an anterior / posterior position. The spinal process should be positioned in the midline between the pedicles to ensure direct anterior / posterior projection.

[0071] (ii) Mark the location of the lateral aspect of the pedicle on the skin. Depending on the depth of the tissue between the skin and the pedicle, the skin incision should be made laterally so that the Jamshidi needle can be properly angled when inserted into the pedicle.

[0072] (iii) Insert the Jamshidi needle through the skin incision and "stop" it on the side of the pedicle.

[0073] (iv) Advance the Jamshidi needle 20 to 25 mm into the pedicle, ensuring that the needle remains on the outer side of the medial pedicle wall.

[0074] (v) Place the intraoperative image intensifier in the lateral plane. The Jamshidi needle should now be in the vertebral body, therefore "safe" with no risk of medial pedicle rupture.

[0075] (vi) Place a Kirschner wire along the Jamshidi wire and place a pedicle tap along the trajectory of the Kirschner wire.

[0076] (vii) Place the last pedicle screw together with the screws placed along the Kirschner wire, ensuring that the Kirschner wire is not pushed beyond the front of the vertebral body.

[0077] In this method, the surgeon's goal is to ultimately position the pedicle screw in the relatively soft core tissue of the vertebra, called "cancellous bone," rather than in the relatively hard shell portion of the vertebra, called "cortical bone." If the surgeon inadvertently punctures the cortical bone, i.e., "damages" the pedicle, serious medical complications can occur, especially initially after entering the pedicle and along the neck and anterior to the vertebral body.

[0078] The aforementioned method of placing pedicle screws relies heavily on intraoperative radiography to avoid these risks and requires constant adjustments to the orientation of the X-ray imaging system. It also presents additional risks of X-ray dose to both the patient and the physician.

[0079] In this invention, an orthotic pin is provided that can be used to improve guidance for the placement of pedicle screws via the above and other related medical procedures. As described above, the orthotic pin of this invention can be provided in the form of a Kirschner wire, which can replace the Kirschner wires described in the above steps to guide the subsequent placement of pedicle screws. As described in more detail below; the Kirschner wire of this invention can generally be used in conjunction with a variety of surgical instruments to provide a properly oriented guide hole that ultimately allows for the subsequent insertion of pedicle screws or other bone implants.

[0080] Figure 1 A handheld surgical tool 130 is shown in the form of an analysis unit including an optical adapter 120, a spectrometer 131, and a processor 136. The analysis unit is connected to an orthotic pin 100, which includes an elongated shaft 101 with a distal end 102.

[0081] The spectrometer 131 includes at least one optical light source (not shown) and at least one optical detector (not shown). The at least one light source and the at least one optical detector are optically coupled to an optical adapter 120 and are arranged such that when the orthotic pin 100 is received within the port of the optical adapter 120 and when the distal end 102 of the elongated shaft 101 of the orthotic pin 100 is inserted into the bone region 110, optical radiation generated by the at least one light source irradiates the bone region 110 (as described below) via the optical fiber device of the orthotic pin, and optical radiation reflected or scattered by the bone region 110 is optically coupled to the at least one optical detector via the optical fiber device.

[0082] Orthopedic pins can be configured as part of a kit that includes surgical devices.

[0083] Figure 2 An example of a kit is shown, which includes an orthotic pin 100 and a pedicle screw 150, wherein the pedicle screw includes a channel 151 for receiving an elongated shaft 101 of the orthotic pin 100.

[0084] Figure 3 Another kit 140 is shown, which includes an orthotic pin 100 received within a channel of a surgical hammer 152.

[0085] In another example, the kit may include an orthotic pin and a hollow drill having a channel configured to receive the orthotic pin. In yet another example, the kit may include an orthotic pin and a surgical screwdriver having a channel configured to receive the orthotic pin. It is also envisioned to provide an orthotic pin in conjunction with a surgical tool that combines hammering, drilling, and tightening functions.

[0086] Figure 4 A modification of the orthotic pin according to the present invention is shown.

[0087] Figure 4 An orthotic pin 100 for optical analysis of bone regions is shown.

[0088] The orthopedic pin includes an elongated shaft 101 having a distal end 102 for insertion into bone 110 and a proximal end 104 for connection to an analysis unit 130. The analysis unit includes a light source 132, a photodetector 134, and a processor 136.

[0089] The fiber optic device 105 extends within the elongated shaft between the distal end 102 and the proximal end 104 of the elongated shaft for transmitting optical radiation between the analysis unit 130 and the bone region 110 when the distal end is inserted into the bone region.

[0090] The coupler 200 is positioned at a midpoint along the shaft (i.e., between the distal and proximal ends). The fiber optic assembly includes a first portion 210 located on one side (proximal) of the coupler 200 and a second portion 212 located on the other side (distal) of the coupler 200. The elongated shaft 101 has a first portion 220 located on one side (proximal) of the coupler and a second portion 222 located on the other side (distal) of the coupler. The coupler 200 allows relative rotation between the portions 220 and 222 of the shaft 101 located on opposite sides of the coupler 200 while maintaining optical coupling between the first portion 210 and the second portion 212 of the fiber.

[0091] This orthotic pin allows rotation of one fiber optic section relative to another. In this way, the distal section can rotate, for example, during the insertion of the shaft into the bone by drilling, screwing, or (rotary) hammering, while the other fiber optic sections remain fixed in rotation, for example, relative to the analysis unit 130. This simplifies the required connection between the proximal section 220 of the shaft and the analysis unit 130.

[0092] The coupling element is detachable, allowing the distal portion 222 of the shaft to be manipulated and used in a conventional manner, such as as a Kirschner needle, without utilizing the fiber optic function. Therefore, the Kirschner needle can be used as a "conventional" Kirschner needle before the coupling element is formed, allowing hollow instruments / screws to slide proximally across the needle (back-loaded). Once a connection is established between the analytical unit and the Kirschner needle, spectral tissue sensing can be performed. This connection is reversible, allowing for repeated connection-disconnection.

[0093] For example, the proximal end of the fiber optic device is configured for non-rotational coupling with the analysis unit 130. This simplifies the connection, but it allows the analysis unit to be located further away, such as outside the doctor's work area. This eliminates the need for miniaturization of the analysis unit.

[0094] Figure 5 The first pair of examples is shown in more detail.

[0095] The fiber optic device 105 has a first fiber optic assembly 230 for optical transmission from the optical analysis unit 130 to the distal end 102 and a second fiber optic assembly 232 for optical transmission from the distal end 102 of the elongated shaft to the optical analysis unit 130. Therefore, different paths are provided for the emitted interrogation light and the reflected detection light.

[0096] exist Figure 5 In the example, the first fiber optic assembly 230 extends along the central axis of the elongated shaft 101 (parts 220 and 222) and includes a single fiber. The second fiber optic assembly 232 extends offset relative to the central axis. Thus, a concentric arrangement of fibers is achieved.

[0097] The second optical fiber assembly 232 includes a single optical fiber 232a located on one side of the coupler and a loop 232b formed by multiple optical fibers located on the other side of the coupler.

[0098] exist Figure 5 In the top portion, a single fiber 232a is located on the near side, while... Figure 5 In the bottom portion, a single optical fiber 232a is located on the far side. An optical fiber splitter 234 combines signals from multiple optical fibers in the loop for use with the detector.

[0099] Then, the coupler can have a set of discrete angular orientations between opposite sides. These angular orientations enable accurate alignment between the fiber ends, especially between the fiber end of a single fiber 232a and one of the fibers in the loop 232b.

[0100] The fiber ends located at the far end are preferably positioned such that the distance between them is greater than the diameter of the fiber. Such a fiber arrangement, in particular, yields good results in terms of diffuse reflectance spectrum.

[0101] Figure 5 The direction of light travel in the optical fiber can be reversed (i.e., the central fiber can be used for reflected light, while the offset fiber can be used for transmitted light).

[0102] Figure 6 Another set of examples using one or more dual-core optical fibers is shown, which includes a center core 240 and an outer core 242.

[0103] One of the central core and the outer core is used for optical transmission from the optical analysis unit to the remote end, and the other of the central core and the outer core is used for optical transmission from the remote end of the slender shaft to the optical analysis unit.

[0104] Figure 6 The example uses a central core to transmit light from the light source, and an outer core to transmit reflected light. The reverse is also possible.

[0105] The image at the top shows the dual-core optical fiber located on each side of the coupler.

[0106] The middle image shows dual-core optical fibers 240 and 242 located on one side (near side) of the coupler, with a loop 232b formed by optical fibers surrounding the central optical fiber 230 located on the other side of the coupler.

[0107] The image at the bottom shows dual-core optical fibers 240, 242 on one side of the coupler, and a single non-central optical fiber 232a on the other side of the optical coupler, offset relative to the central optical fiber 230.

[0108] Lenses can be used to couple light from the outer fiber to the central fiber.

[0109] Figure 7 An optical fiber device is shown, which includes an external optical fiber device located on one side (far side) of the coupler. The external optical fiber device includes a non-central optical fiber 232a (top image) or a loop 232b formed by the non-central optical fiber (bottom image), in both cases around the central optical fiber 230.

[0110] On the other side of the coupler, there is only the central optical fiber 230.

[0111] Lens 250 is configured to focus light from an external fiber optic device onto the central fiber optic cable.

[0112] The central optical fiber 230 then serves as a bidirectional optical signal conductor. An optical fiber splitter 252 can then be provided to separate the two signals returning to the analysis unit 130.

[0113] This method can also be applied to dual-core optical fibers. Moreover, the single-core fiber can be located on the far side, while the concentric arrangement can be located on the near side.

[0114] Figure 7 A method that can be executed by the processor 132 of the analysis unit is shown.

[0115] In step 700, the light source is operated to generate optical radiation for optical irradiation of the bone region 110;

[0116] In step 702, an electrical signal generated by at least one photodetector in response to optical irradiation of bone region 110 is received;

[0117] In step 704, the received electrical signal is analyzed to determine at least a first parameter of fat content or water content within the indicated bone region 110 based on the received electrical signal.

[0118] In step 706, the type of bone region 110 is analyzed and identified based on at least a first parameter; the type is at least one of cancellous bone and cortical bone.

[0119] Optionally, the algorithm can be further configured to determine at least a second parameter indicating the collagen content and / or optical scattering in the bone region 110 and further identify the type of the bone region 110 based on the at least second parameter.

[0120] Including collagen and / or optical scattering in the analysis can further improve the distinction between cortical and cancellous bone.

[0121] Furthermore, the algorithm can be further configured to determine the blood content within bone region 110.

[0122] The surgical tool may also include an indicator; wherein the indicator is configured to generate a first output if the type of bone region 110 is cancellous bone, and a second output if the type of bone region 110 is cortical bone 110b. A third output indicating the definitive identification of the type of bone region 110 may also be provided based on a determined blood content within the bone region 110.

[0123] It has been found that the certainty of identifying the type of bone region is inversely correlated with blood content. This is because if an orthotic pin is inserted into the bone region and then slightly withdrawn, the gap created between the distal end of the pin and the bone region tends to be filled with blood. Since there is no contact between the distal end and the bone region, the light signal may be unreliable. Therefore, if blood is detected in the light signal, it may indicate an unreliable signal.

[0124] In the literature “Estimation of biological chromophores using diffuse optical spectroscopy: benefit of extending the UV-VIS wavelength range to include 1000 to 1600 nm” by R. Nachabe, BHWHendriks, MVDVoort, AE, and HJCMSterenborg (Optics Express, Vol. 18, 2010, pp. 879-888) and in the literature “Estimation of lipid and water concentrations in scattering media with diffuse optical spectroscopy from 900 to 1600 nm” by R. Nachabe, BHWHendriks, AEDesjardins, M. van der Voort, MB van der Mark, and HJCMSterenborg, the literature “Estimation of lipid and water concentrations in scattering media with diffuse optical spectroscopy from 900 to 1600 nm” by R. Nachabe, BHWHendriks, AEDesjardins, M. van der Voort, MB van der Mark, and HJCMSterenborg, the literature “Estimation of lipid and water concentrations in scattering media with diffuse optical spectroscopy from 900 to 1600 nm” by R. Nachabe, BHWHendriks, MVDVoort, AE, and HJCMSterenborg A technique for determining the aforementioned optical parameters transmitted by optical fiber 105 is described in "Estimation of lipid and water concentrations in the scattering medium using diffuse reflectance spectroscopy from 900 to 1600 nm" (Journal of Biomedical Optics, vol. 15, May 2010, pp. 037015-10). This technique involves optical analysis of a bone region 110 based on diffuse reflectance spectroscopy from the bone region to determine these parameters. From these diffuse reflectance spectroscopy (i.e., DRS) measurements, tissue transitions can be inferred, and more specifically, parameters indicating the fat content of the tissue can be obtained.

[0125] Although diffuse reflectance spectroscopy has been described above as being used to extract tissue properties, other optical methods are also conceivable, including diffuse optical tomography using multiple optical fibers, differential path length spectroscopy, fluorescence, and Raman spectroscopy. Furthermore, optical data acquisition can be accomplished using probes that contact the tissue or using non-contact probes.

[0126] To determine whether a tissue is in front of an optical fiber, the DRS signal can be compared with a lookup table. Another approach is to convert the measured parameters into physiological parameters and define ranges for these parameters for each tissue type. Referring to Duck, FA, “Physical properties of tissue: A comprehensive reference book” (1990, Academic Press, Harcourt Brace Jovanovich Publishers), a method based on classification and regression tree “CART” analysis is described as being used for tissue classification based on these physiological parameters.

[0127] An example of extracting physiological parameters is the fitting of the acquired spectrum using a custom Matlab 7.9.0 (Mathworks, Natick, MA) algorithm. This algorithm implements a widely accepted analytical model, namely the model introduced by TJ Farrel, MS Patterson, and BC Wilson, “Adiffusion theory model of spatially resolved, steady-state diffuse reflectance for the non-invasive determination of tissue optical properties” (Med. Phys. 19 (1992), pp. 879-888). The input parameter to Farrel et al.'s model is the absorption coefficient μ. a (λ), reduced scattering coefficient μ s '(λ) and the center-to-center distance between the transmitting and collecting fibers at the probe tip. For a complete description of the diffusion theory model, please refer to the literature of Farrel et al.

[0128] The model will be briefly explained below. These formulas are primarily based on the work of Nachabé et al. (R. Nachabé, BHWHendriks, MVDVoort, AE, and HJCMSterenborg, “Estimation of biological chromophores using diffuse optical spectroscopy: benefit of extending the UV-VIS wavelength range to include 1000 to 1600 nm” (Optics Express, Vol. 18, 2010, pp. 879-888)), and also refer in context to R. Nachabe, BHWHendriks, AEE Desjardins, M. van der Voort, MB van der Mark, and HJCMSterenborg, “Estimation of lipid and water concentrations in scattering media with diffuse optical spectroscopy from 900 to 1600 nm”. 1600 nm (using diffuse reflectance spectroscopy from 900 to 1600 nm to estimate lipid and water concentrations in the scattering medium) (Journal of Biomedical Optics, vol. 15, May 2010, pp. 037015-10).

[0129] The double power-law function can be used to describe the wavelength dependence of the reduced scattering coefficient, where the wavelength λ is denoted in nm and normalized to a wavelength value of λ0 = 800 nm. The parameter α corresponds to the reduced scattering amplitude at that specific wavelength.

[0130]

[0131] In this formula, the reduced scattering coefficient is expressed as the sum of Mie scattering and Rayleigh scattering, where ρ MR It is the fraction of Mie scattering to the total reduced scattering. The reduced scattering slope of Mie scattering is denoted by b and is related to the grain size.

[0132] For a uniformly distributed absorber, the total light absorption coefficient μ a(λ) can be calculated as the product of the extinction coefficient and the volume fraction of the absorber (see Figure 17, which shows a logarithmic plot of the absorption spectra of blood hemoglobin (line 220), oxyhemoglobin (line 221), water (line 222), and fat (line 223), where the horizontal axis represents wavelength in nm and the vertical axis represents μ). a (λ), in cm -1 ):

[0133]

[0134] Instead of the absorption coefficient μ a (λ) is modeled as the sum of absorption coefficients weighted by the corresponding concentrations of the four chromophores of interest, determining how the tissue absorption coefficient is expressed as...

[0135]

[0136] in Corresponding to absorption in the blood, and This corresponds to the absorption of water and lipids in the volume being detected. The volume fractions of water and lipids are v. WL = [Lipid] + [H2O], while v Blood The blood volume fraction indicating the concentration of hemoglobin in whole blood is 150 mg / ml.

[0137] Factor C is a wavelength-dependent correction factor that explains the effects of pigment packaging and alters the shape of the absorption spectrum. This effect can be explained by the fact that blood in tissue is confined to a small fraction of its total volume, namely, blood vessels. Therefore, red blood cells near the center of the vessels absorb less light than those at the periphery. In fact, when uniformly distributed within the tissue, fewer red blood cells would produce the same absorption as the actual number of red blood cells distributed in discrete blood vessels. The correction factor can be described as:

[0138]

[0139] Where R represents the average blood vessel radius in cm. The blood-related absorption coefficient is given by the following formula:

[0140]

[0141] in and The spectra represent the fundamental extinction coefficients of oxyhemoglobin (HbO2) and deoxyhemoglobin (Hb), respectively. The fraction of oxyhemoglobin in the total hemoglobin is denoted as α. BL = [HbO2] / ([HbO2]+[Hb]), and is commonly referred to as blood oxygen saturation. The absorption due to the presence of water and lipids in the tissue being measured is defined as:

[0142]

[0143] In this case, the lipid concentration associated with the total concentration of lipids and water can be written as α. WF = [Lipid] / ([Lipid]+[H2O]), where [Lipid] and [H2O] correspond to the concentrations of lipid (density 0.86 g / ml) and water, respectively.

[0144] This method of relating water and lipid parameters in the expression for the absorption coefficient is defined in Equation 6, rather than estimating the volume fractions of water and lipids separately for minimizing the covariance of the basic function used for fitting, thus leading to a more stable fit (see the aforementioned paper by R. Nachabé et al. for further explanation and verification of the theory).

[0145] Other light absorbers can also be included in the algorithm, such as lycopene, vitamin A, beta-carotene, or bile.

[0146] Another method for distinguishing spectral differences is to utilize principal component analysis. This method allows for the classification of spectral differences, thereby enabling the differentiation of tissues. Features can also be extracted from the spectra.

[0147] In addition to diffuse reflectance, fluorescence spectra can also be measured. For example, parameters such as those of collagen, elastin, reduced forms of nicotinamide adenine dinucleotide (NADH), and flavin adenine dinucleotide (FAD) can be measured (see Figure 18, which shows the intrinsic fluorescence curves of collagen, elastin, NADH, and FAD, where the horizontal axis represents wavelength in nm and the vertical axis represents fluorescence intensity in arbitrary units. The NADH / FAD ratio, known as the optical redox parameter, is significant because it is an indicator of tissue metabolic state (see M. Müller and BHW Hendriks, “Recovering intrinsic fluorescence by Monte Carlo modeling” (J. Biomed. Optics, 18 (2013), pp. 027009-1 to 027009-13) and its references), and it can also be used to differentiate tissues.

[0148] It should be noted that any method steps disclosed herein, particularly those described with respect to processor 132, may be recorded as instructions that, when executed on the processor, cause the processor to perform such method steps.

[0149] Instructions may be stored on a computer program product. The computer program product may be provided by dedicated hardware and hardware capable of executing software associated with appropriate software. When provided by a processor, functionality may be provided by a single dedicated processor, a single shared processor, or multiple separate processors (some of which may be shared). Furthermore, the explicit use of the terms "processor" or "controller" should not be construed as specifically referring to hardware capable of executing software, and may implicitly include, but is not limited to, digital signal processor (DSP) hardware, read-only memory (ROM) for storing software, random access memory (RAM), non-volatile memory, etc. Furthermore, embodiments of the invention may take the form of a computer program product accessible from a computer-usable or computer-readable storage medium that provides program code (for use by or in connection with a computer or any instruction execution system). For the purposes of this description, a computer-usable or computer-readable storage medium may be any means that may include, store, communicate, propagate, or transmit a program (for use by or in connection with an instruction execution system, apparatus, or device). The medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or a propagation medium. Examples of computer-readable media include semiconductor or solid-state memory, magnetic tape, removable computer floppy disks, random access memory (RAM), read-only memory (ROM), hard disks, and optical disks. Current examples of optical disks include optical disc-read-only memory (CD-ROM), optical disc-read / write (CD-R / W), and Blu-ray discs. TM and DVD.

[0150] The above reference Figures 5 to 7 The detailed examples described all feature a concentric arrangement of optical fibers with different paths in two directions.

[0151] Conversely, bidirectional optical transmission can be achieved using a single-core fiber. As in the example above, an optical splitter can be used to extract the signal from the bidirectional fiber for analysis. In this case, Figure 4 The fiber optic device 105 can be a single fiber.

[0152] The light source, detector, and processor (forming an optical spectral unit) can all be integrated as part of a handheld surgical instrument, implemented as a detachable knob for attaching to the proximal end of a slender shaft and fiber optic device.

[0153] Another option is to integrate the optical spectral unit with the placement tool (such as a drill bit). The integrated optical spectral unit can be fixed to a fixed part of the placement tool (otherwise, extreme miniaturization of the optical spectral unit would be required), and thus can be fixed to one side of the aforementioned coupler. The rotating drill bit is then connected to a rotating fiber optic Kirschner wire located on the other side of the aforementioned coupler. The Kirschner wire is then connected and disconnected from the placement tool at the coupler.

[0154] For example, the distal portion of the fiber optic device and the distal portion of the slender shaft have a length of less than 100 cm, for example, in the range of 10 cm to 50 cm. The proximal portion of the fiber optic device and the proximal portion of the slender shaft can be very short, for example, if the analysis unit is part of a handheld tool and the coupler is located at the interface of the handheld tool. If the analysis unit is outside the surgical area, the proximal portion can be longer, for example, exceeding 2 m, for example, in the range of 3 m to 4 m.

[0155] By studying the accompanying drawings, this disclosure, and the appended claims, those skilled in the art can understand and implement variations of the disclosed embodiments when carrying out the claimed invention. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality.

[0156] The fact that certain measures are described only in mutually different dependent claims does not mean that a combination of these measures cannot be used to exert an advantage.

[0157] If the term “suitable” is used in the claims or description, it should be noted that the term “suitable” is intended to be equivalent to the term “configured as”.

[0158] Any reference numerals in the claims should not be construed as limiting their scope.

Claims

1. An orthotic pin (100) for optical analysis of a bone region (110), the orthotic pin comprising: The slender shaft (101) has a distal end (102) for insertion into bone and a proximal end (103) for connection to the analysis unit. An optical fiber device (105) extending from the distal end to the proximal end of the elongated shaft within the elongated shaft is used to transmit optical radiation from the analysis unit to the bone region (110) when the distal end (102) is inserted into the bone region (110), and to transmit reflected optical radiation from the bone region to the analysis unit. and A mechanical and optical coupling element (200) is located at the midpoint along the shaft; The optical fiber device includes a first part (210) located on one side of the coupler and a second part (212) located on the other side of the coupler, each part being used to transmit the transmitted optical radiation and the reflected optical radiation; The elongated shaft (101) includes a proximal portion (220) on one side of the coupling member and a distal portion (222) on the other side of the coupling member; and The coupling member (200) allows relative rotation between the proximal and distal portions of the elongated shaft located on opposite sides of the coupling member, and relative rotation between the first and second portions of the optical fiber device located on opposite sides of the coupling member, while maintaining optical coupling between the first and second portions of the optical fiber device.

2. The orthotic pin according to claim 1, wherein, The coupling element enables detachable coupling between the first part and the second part.

3. The orthotic pin according to claim 1 or 2, wherein, The proximal end of the optical fiber device is configured for non-rotational coupling with the analysis unit.

4. The orthotic pin according to claim 1 or 2, wherein, The coupler has a set of discrete angular orientations between the opposite sides.

5. The orthotic pin according to claim 1 or 2, wherein, The optical fiber device includes a first optical fiber assembly for optical transmission from the analysis unit to the distal end and a second optical fiber assembly for optical transmission from the distal end of the elongated shaft to the analysis unit.

6. The orthotic pin according to claim 5, wherein, One of the first fiber optic assembly and the second fiber optic assembly extends along the central axis of the elongated shaft, and the other of the first fiber optic assembly and the second fiber optic assembly extends offset relative to the central axis.

7. The orthotic pin according to claim 6, wherein, The other of the first and second fiber optic assemblies includes a single fiber located on one side of the coupler and a loop formed by a plurality of fibers located on the other side of the coupler.

8. The orthotic pin according to claim 1 or 2, wherein, The optical fiber device includes a dual-core optical fiber comprising a central core and an outer core, wherein one of the central core and the outer core is used for optical transmission from the analysis unit to the distal end, and the other of the central core and the outer core is used for optical transmission from the distal end of the elongated shaft to the analysis unit.

9. The orthotic pin according to claim 8, wherein: The dual-core optical fiber is located on one side of the coupling element, and the loop formed by multiple optical fibers is located on the other side of the optical coupling element; or The dual-core optical fiber is located on one side of the coupler, and the single non-central optical fiber is located on the other side of the optical coupler; or A dual-core optical fiber is provided on each side of the coupling element.

10. The orthotic pin according to claim 8, wherein, The optical fiber device includes: An external optical fiber device located on one side of the coupling member, comprising one or more non-central optical fibers or an outer core of a dual-core optical fiber. The central optical fiber located on the other side of the coupler; and A lens, used to focus light from the external fiber optic device onto the central fiber optic cable.

11. The orthotic pin according to claim 10, wherein, The orthopedic pin also includes an optical fiber splitter for separating signals from the central optical fiber.

12. A surgical instrument comprising: The orthotic pin according to any one of claims 1 to 11; as well as The analysis unit is used to connect to the proximal end of the elongated shaft.

13. The surgical tool according to claim 12, wherein, The analysis unit includes a light source and an optical detector coupled to the fiber optic device.

14. The surgical tool according to claim 13, wherein, The analysis unit includes a spectrometer having the optical detector and processor. The light source is used to generate optical radiation that illuminates the bone region (110) via the optical fiber device (105), and the optical radiation reflected or scattered by the bone region (110) is optically coupled to the optical detector via the optical fiber device (105). The processor (136) is configured to: This causes the light source to generate optical radiation for optically irradiating the bone region (110); Receives an electrical signal generated by the optical detector in response to optical irradiation of the bone region; The received electrical signal is processed using an algorithm, which is configured to: Based on the received electrical signal, at least one first parameter indicating the fat or water content within the bone region (110) is determined; and Based on the at least one first parameter, the type of the bone region (110) is identified; the type is at least one of cancellous bone and cortical bone.

15. The surgical instrument according to any one of claims 12 to 14, wherein, The surgical tools also include: Pedicle screw (150) having a central channel for receiving the elongated shaft; and A hollow drill having a channel configured to receive the orthopedic pin; and / or A surgical screwdriver having a channel configured to receive the orthopedic pin; and / or A surgical hammer (152) having a channel (151) configured to receive the orthopedic pin (100).

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