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WO2024193955A1 - Implant médical avec une vis d'implant - Google Patents

Implant médical avec une vis d'implant Download PDF

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Publication number
WO2024193955A1
WO2024193955A1 PCT/EP2024/054961 EP2024054961W WO2024193955A1 WO 2024193955 A1 WO2024193955 A1 WO 2024193955A1 EP 2024054961 W EP2024054961 W EP 2024054961W WO 2024193955 A1 WO2024193955 A1 WO 2024193955A1
Authority
WO
WIPO (PCT)
Prior art keywords
implant
screw
markers
threaded shaft
marker
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/EP2024/054961
Other languages
German (de)
English (en)
Inventor
Roger SCHELLING-NEYER
Hermann Backes
Daniela Jenifer STADELMANN
Roger Heinrich STADLER
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Icotec Ag
Original Assignee
Icotec Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Icotec Ag filed Critical Icotec Ag
Priority to AU2024238258A priority Critical patent/AU2024238258A1/en
Publication of WO2024193955A1 publication Critical patent/WO2024193955A1/fr
Anticipated expiration legal-status Critical
Pending legal-status Critical Current

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Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/70—Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant
    • A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
    • A61B17/7032—Screws or hooks with U-shaped head or back through which longitudinal rods pass
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
    • A61B17/86—Pins or screws or threaded wires; nuts therefor
    • A61B17/8625—Shanks, i.e. parts contacting bone tissue
    • A61B17/8635—Tips of screws
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
    • A61B17/86—Pins or screws or threaded wires; nuts therefor
    • A61B17/866—Material or manufacture
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/39—Markers, e.g. radio-opaque or breast lesions markers
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/70—Spinal positioners or stabilisers, e.g. stabilisers comprising fluid filler in an implant
    • A61B17/7001—Screws or hooks combined with longitudinal elements which do not contact vertebrae
    • A61B17/7035—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other
    • A61B17/7037—Screws or hooks, wherein a rod-clamping part and a bone-anchoring part can pivot relative to each other wherein pivoting is blocked when the rod is clamped
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B17/00—Surgical instruments, devices or methods
    • A61B17/56—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
    • A61B17/58—Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor for osteosynthesis, e.g. bone plates, screws or setting implements
    • A61B17/68—Internal fixation devices, including fasteners and spinal fixators, even if a part thereof projects from the skin
    • A61B17/84—Fasteners therefor or fasteners being internal fixation devices
    • A61B17/86—Pins or screws or threaded wires; nuts therefor
    • A61B17/8625—Shanks, i.e. parts contacting bone tissue
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B90/00—Instruments, implements or accessories specially adapted for surgery or diagnosis and not covered by any of the groups A61B1/00 - A61B50/00, e.g. for luxation treatment or for protecting wound edges
    • A61B90/39—Markers, e.g. radio-opaque or breast lesions markers
    • A61B2090/3966—Radiopaque markers visible in an X-ray image

Definitions

  • the present invention relates to a medical implant with an implant screw, in particular a pedicle screw, and a method for planning irradiation in medical radiotherapy.
  • Implant screws bone screws
  • the implant screws can be connected to one another by other implant parts, as is the case, for example, in spinal implant systems with pedicle screws and connecting rods.
  • Implants and in particular the implant or bone screws are usually made of metal, for example titanium and/or a titanium alloy.
  • Such implants are radiopaque and allow the precise position of the implant (for example the pedicle screw) to be determined when the patient is examined using an imaging procedure, for example computer tomography (CT).
  • CT computer tomography
  • metal implants hinder the view of the bone connected to the implant and the surrounding tissue during fluoroscopy because they are radiopaque and, in addition, scattering effects occur during fluoroscopy, which in turn create artifacts in the area of the implant when visualized.
  • Due to their radioopacity metal implants also impair the radiotherapy of cancer patients because scattering phenomena occur due to the relatively large metallic mass. which reduce the effectiveness of the radiation and thus require a higher radiation dose, which in turn can cause side effects in the surrounding tissue.
  • bone implants or bone implant systems made of non-metallic composite materials have been developed, which are generally radio-transparent and do not have the above-mentioned disadvantages.
  • the market preference is for implants or implant systems made of non-metallic composite materials based on carbon fiber-reinforced polyetheretherketone (PEEK).
  • PEEK carbon fiber-reinforced polyetheretherketone
  • the implants in question can be, for example, cages, bone plates, pedicle rods, tulips or pedicle screws.
  • markers are usually made from metals, particularly preferably from tantalum or titanium and their alloys, and are inserted or attached to the implant.
  • Known versions of such markers are spherical or wire-shaped or in the form of a coating.
  • the document US 10,154,867 B2 describes various embodiments of a bone screw made of composite material. This can in particular be a pedicle screw which is partially coated with a metallic outer layer.
  • Claim 16 specifies a method for planning radiation in medical radiotherapy, which is preferably based on such a medical implant.
  • Advantageous embodiments of the invention are specified in the dependent claims.
  • the present invention therefore provides a medical implant with an implant screw, in particular a pedicle screw, which has a screw head and a threaded shaft and is made of a plastic material, wherein the implant has radiopaque markers to allow a determination of the spatial position and preferably the orientation of the implant screw in an imaging method.
  • an implant screw in particular a pedicle screw, which has a screw head and a threaded shaft and is made of a plastic material, wherein the implant has radiopaque markers to allow a determination of the spatial position and preferably the orientation of the implant screw in an imaging method.
  • One or more of the markers together form a ring with a ring center located inside the screw head. Another of the markers is located on or in the threaded shaft.
  • the position of the implant can be determined very precisely using an imaging procedure, such as computer tomography (CT), but also its orientation.
  • CT computer tomography
  • the position of the screw head can be determined using the marker(s) forming a ring, and the direction along which the implant is moving can be determined using the other marker.
  • the threaded shaft extends from the screw head. Since the geometry of the implant screw and in particular the length of the threaded shaft is usually known, the position and orientation of the implant screw can be determined very precisely from this.
  • the orientation, i.e. in particular the inclination, of the implant screw relative to this other part of the implant can also be determined. Since a marker ring can be seen in the area of the screw head in the imaging process instead of just a marker point, for example, not only the position of the screw head can be determined particularly precisely (due to the arrangement of the ring center within the screw head), but also its orientation or the orientation of another part of the implant relative to the screw.
  • the markers can be designed in such a way that they are relatively clearly visible in the imaging process, i.e. they produce a strong contrast, in particular by being highly radio-opaque, which allows a particularly precise determination of the spatial position and orientation of the implant. Since the radio-opacity only affects the geometrically limited markers and thus occurs in a concentrated form at a few places on the implant, the implant can otherwise still be largely radio-transparent.
  • the precise determination of the spatial position and orientation of the implant and in particular of the implant screw using an imaging procedure i.e. contactless, enables, for example, a control or even monitoring of the implant after it has been implanted in a human or animal body.
  • the tilting/inclination of the pedicle screw can be determined in relation to a fastening element, often referred to in technical jargon as a tulip, which is used to connect the pedicle screw to a connecting rod.
  • a fastening element often referred to in technical jargon as a tulip, which is used to connect the pedicle screw to a connecting rod.
  • imaging procedure is considered to be a procedure known in medicine in particular, which advantageously enables the implant implanted in the body of a human or animal patient and/or the surrounding body tissue to be visualized without contact.
  • imaging procedures are understood to mean various instrumental examination methods that provide two-, three- or higher-dimensional image data of the patient's organs and structures and/or the implant implanted in them and are often used primarily to diagnose disease-related changes, for example. Examples of imaging procedures are X-rays, computer tomography (CT), ultrasound and magnetic resonance imaging (MRI).
  • a medical implant is an artificial device that is implanted or can be implanted in the human or animal body and is usually intended to remain there permanently or at least for a longer period of time, i.e. at least for several hours or days.
  • the implant can usually be anchored in a part of the body, usually a bone or cartilage, using the implant screw.
  • the implant screw usually has an external thread with which it can be screwed into the corresponding part of the body.
  • the threaded shaft of the implant screw usually extends from the screw head to a free end of the threaded shaft, i.e. the screw tip.
  • the external thread preferably, but not necessarily, extends continuously over the entire length of the threaded shaft.
  • the threaded shaft can also have one or more thread-free sections, i.e. the external thread can be interrupted once or several times in the longitudinal direction. A thread-free section can be present in particular in the area adjacent to the screw head. Preferably, however, the external thread extends to the screw tip.
  • the threaded shaft and in particular the external thread define a main longitudinal central axis of the implant screw, which extends centrally and longitudinally through the threaded shaft.
  • the screw head of the implant screw is preferably round, even more preferably in Essentially spherical.
  • essentially spherical is meant that it can have flattened areas, in particular due to an engagement structure, but preferably has a spherical overall casing.
  • the screw head is therefore suitable for being attached to another component in such a way that the implant screw can pivot polyaxially relative to it.
  • the engagement structure is advantageously used for screwing in the implant screw using a suitable tool.
  • the other component mentioned can in particular be another part of the implant.
  • the pivotability can be provided before the implant screw is definitively attached to the other part, for example by tightening a clamping part, or also afterwards.
  • the polyaxial pivotability can in particular be provided by a type of ball joint.
  • the implant screw can in particular be a pedicle screw, i.e. a screw that is designed to be screwed into a vertebral body of a human or animal spine.
  • the screw head is then preferably designed to be connected to a connecting rod using a tulip-shaped fastening element, for example.
  • the implant screw and the connecting rod then form components of a pedicle system.
  • the implant screw can be used, for example, to attach an implant plate to a bone.
  • the implant can therefore also have several implant screws, in which case some or all of the implant screws can have the radiopaque markers mentioned.
  • the aforementioned determination of the spatial position of the implant screw means that the location where the implant screw is arranged in the patient's body can be determined using an imaging method.
  • the determination of the location is advantageously carried out in relation to a reference point that can be arranged inside or outside the body.
  • the spatial orientation of the implant screw does not generally have to be determined, i.e. it can only be determined where the screw is arranged as a whole, for example in relation to its center of mass, but not, for example, in which position the screw is arranged and in which direction the threaded shaft extends.
  • a determination of the spatial orientation of the implant screw is possible with the implant specified here due to the combination that one or more of the markers together form a ring and that another of the markers is on or in the threaded shaft. is arranged.
  • Radiopacity also known as X-ray opacity, refers to the property of the radiation permeability of materials or components for X-rays.
  • a radiopaque material or component is less permeable to X-rays than other surrounding materials or components and therefore weakens the X-rays when they penetrate it.
  • the markers mentioned therefore relate to a material or component (or part of a component) that is less permeable to X-rays than other parts of the implant.
  • the markers are less permeable than the plastic material of the pedicle screw. In the imaging process, the markers therefore appear lighter or darker compared to the surrounding areas, depending on the type of representation.
  • the radiopacity of the markers preferably differs by at least an integer multiple, more preferably by at least twice, even more preferably by at least five times, most preferably by at least ten times, from that of the plastic material of the pedicle screw.
  • a ring is generally considered to be a geometric structure that encircles a center point and can have a certain extension in both the radial and axial directions. Due to its radial extension, the ring can be formed, for example, by a surface extending between two concentric circles. Due to its axial extension, the ring can also be formed, for example, by a hollow cylindrical structure. Usually, the ring formed by the marker(s) has both a certain radial and a certain axial extension. This means that the ring can be formed, for example, by a hollow cylindrical structure that can have a certain wall thickness (due to the radial extension). Thus, in the context of the present document, a hollow cylindrical structure as a whole is also considered to be a ring, with the ring center then being in the axial center of the hollow cylindrical structure. The ring is preferably, but not necessarily, exactly circular.
  • the ring is formed by several markers together, it can be formed by a common envelope of the corresponding marker(s).
  • the markers can, for example, be point-shaped or spherical and form the corner points of any regular polygon.
  • the number of corners of the Polygons can be three, four, five or greater than five.
  • the ring is formed by a single marker that is continuous in the circumferential direction.
  • a ring marker not only enables particularly simple production of the implant, but also allows the position and orientation of the implant screw to be particularly clearly identified in the imaging process.
  • the position and orientation of the implant screw can not only be recognized in the imaging process, but also measured clearly and precisely. This enables non-contact monitoring of the implant screw after implantation.
  • a change in the inclination of the screw relative to a connecting rod detected during monitoring via time-delayed CT images can indicate a possible loosening of the blocking of the tulip with the rod.
  • the stability of the blocking can be verified with the help of the monitoring.
  • the ring center is arranged exactly in the center of the screw head.
  • the position of the screw head can therefore be recognized particularly intuitively in the imaging process. If the marker(s) forming the ring are not arranged in or on the implant screw itself, but rather, as is preferred, on another part of the implant, the arrangement of the ring center in the center of the screw head also has the advantage that the position of the screw head is always correctly displayed regardless of the pivoting of the screw relative to this other part. It is particularly preferred if the ring center is also arranged in a center of rotation, pivot point or in a pivot axis of the implant screw.
  • the ring center is preferably arranged in a center of rotation, pivot point or in a pivot axis of the implant screw when the fastening element is firmly fixed to the implant screw. It is also preferred if the ring formed by the one or more markers has an inner diameter that is larger than an outer diameter of the screw head.
  • the marker arranged on or in the threaded shaft is preferably arranged in the last third of the threaded shaft along a longitudinal direction that extends from the screw head to a free end of the threaded shaft. In comparison to an arrangement of the marker close to the screw head, the orientation of the screw can be determined more easily.
  • the marker arranged on or in the threaded shaft is even arranged at the free end of the threaded shaft, i.e. at the screw tip. This not only makes it particularly easy to determine the orientation of the screw, but the viewer can also immediately and intuitively recognize the length of the implant screw in the imaging process.
  • the implant screw In order to enable particularly simple production and to make the implant screw particularly stable and good at conducting forces, it is preferably made as a single piece.
  • the implant has a fastening element for attaching, in particular fixing, the implant screw.
  • the fastening element which can in particular be tulip-shaped, serves to fasten the implant screw to a connecting rod.
  • the implant screw is then preferably a pedicle screw.
  • the fastening element preferably has the marker(s) forming a ring.
  • the marker or markers forming a ring are formed by a screw element that can be screwed onto the fastening element.
  • the fastening element and/or the screw element are preferably each formed as a single piece.
  • the screw element, which can be screwed onto or into the fastening element, is preferably made as a whole from a radiopaque material. Alternatively, the screw element can also have a radiopaque coating.
  • the screw element serves to hold the implant screw on the fastening element.
  • the implant screw attached to the fastening element can advantageously be pivoted polyaxially around the ring center with the threaded shaft relative to the fastening element. Due to the ring marking, the inclination of the implant screw relative to the fastening element can be determined using the imaging procedure.
  • One or more markers can be arranged on or in the threaded shaft.
  • the marker(s) arranged on or in the threaded shaft can also have any shape. According to a preferred embodiment, however, at least one of the markers arranged on or in the threaded shaft is spherical. This makes the marker particularly easy and clear to recognize in imaging. It is also easier to manufacture if exactly one marker is arranged on the threaded shaft.
  • the marker arranged on or in the threaded shaft is ring-shaped, in particular sleeve-shaped.
  • a shape of the marker is particularly suitable for a cannulated implant screw.
  • a channel running longitudinally through the threaded shaft then preferably extends through the ring- or sleeve-shaped marker, so that, for example, medication or bone cement can be supplied to the patient through the marker along the main longitudinal center axis of the implanted screw.
  • the ring center of the ring formed by the marker(s) is preferably arranged on the main longitudinal center axis of the implant screw.
  • the marker arranged on or in the threaded shaft also forms a center that is arranged on the main longitudinal center axis of the implant screw. In this way, the position of the implant screw can be directly determined based on the position of the markers visible in the imaging.
  • the markers are preferably made from a metal, particularly tantalum or titanium.
  • Metal is generally well suited as a radiopaque material. Tantalum and titanium are particularly biocompatible and can be used well in production.
  • the plastic material of the implant screw is preferably a thermoplastic material. Particularly preferred are so-called high-temperature thermoplastics from the families of polyaryletherketones, polyimides and Polysulfones are used. Polyetheretherketone (PEEK) has proven to be a particularly suitable plastic material. The plastic material PEEK has proven to be particularly suitable for pedicle screws in spinal implants, but also for other implants, particularly due to its hardness and durability as well as its good processability and biocompatibility.
  • the plastic material of the implant screw is preferably fiber-reinforced, in particular carbon fiber-reinforced. In this way, a particularly high level of strength of the implant screw can be achieved.
  • the plastic material of the implant screw can therefore be a composite material, preferably in the form of carbon fiber-reinforced PEEK.
  • the fiber length is preferably at least 1 mm.
  • the fibers advantageously have a length that corresponds at least to the complete length of the implant screw along its main extension direction.
  • the fiber volume content is preferably in a range of 20 to 80%, more preferably in a range of 35 to 70%, particularly preferably in a range of 45 to 60%.
  • the basic production of the implant screw can be carried out using a process that is conventionally known in the composite sector. These include pressing processes, winding processes, tape laying processes and pultrusion processes.
  • the pressing process described in document DE 44 45 305 C1 is preferred for producing the implant screw and, if present, the fastening element, for example in the shape of a tulip head.
  • the implant can also be produced using so-called additive manufacturing processes, such as the 3D printing process, or a combination of the above-mentioned processes.
  • the starting materials used in these processes are preferably so-called unidirectional pregregs and fabric prepregs. Both are geometrically flat or round-shaped starting materials.
  • the prepregs are preformed into preforms and welded under pressure and temperature, for example in a pressing tool, and then cooled.
  • the insertion or positioning of the markers can be done mechanically, for example by pressing or screwing a marker into the screw tip of the implant screw or by inserting the marker into a tool mold in which this marker is formed during the manufacture of the implant part, for example using the pressing process described in document DE 44 45 305 C1, and is thus integrated into the implant part.
  • the fastening element this can be done, for example, by inserting a ring-shaped marker into a tool mold.
  • a ring-shaped marker can be attached and positioned on the fastening element in such a way that the marker is screwed, snapped or locked onto a main part of the fastening element.
  • the marker(s) can be attached or integrated on the outside or inside of the fastening element.
  • the marker(s) can be applied to the implant screw or to another part of the implant, such as the fastening element, using known coating processes.
  • coating processes include, for example, galvanic coating methods, plasma coating, laser cladding, flame spraying, and 3D printing methods.
  • the above-mentioned methods for producing a medical implant with integrated markers are preferably near-net-shape manufacturing processes, which means that such manufactured implants generally require only minor post-processing in terms of shape and dimensions, during which the positioning of the markers is retained.
  • the invention also relates to a method for planning irradiation in medical radiotherapy, in which one or more radiopaque markers are used in an imaging method as a spatial reference for planning the therapeutic irradiation of a human or animal patient, wherein the one or more markers are attached to or in the body of the patient.
  • the marker or markers are each arranged on or in the threaded shaft of an implant screw, preferably a pedicle screw, which is made of a plastic material and anchored in the body, preferably in a bone, of the patient.
  • the screw mentioned, on or in whose threaded shaft the marker or markers are arranged, is particularly preferably an implant screw of a medical implant according to the above statements.
  • the procedure for planning radiation in medical radiotherapy therefore includes the step of using one or more radiopaque markers in the imaging procedure as a spatial reference for planning the therapeutic
  • the radiopaque markers arranged on the implant screws and used for radiation planning can also be referred to as fiducial markers.
  • the one or more radiopaque markers arranged on the threaded shaft can be used in the method mentioned in particular to determine the spatial position of the body area or areas to be irradiated. Since the one or more screws made of a plastic material are usually each firmly anchored in the body anyway, the radiopaque marker or markers arranged on them can be used very easily for particularly precise and reliable planning of the therapeutic irradiation. For patients who need to be therapeutically irradiated and who already have at least one such screw implanted in their body, a further medical intervention to position reference markers can thus be partially or even completely dispensed with. With the method specified, it is therefore possible to dispense with the implantation of markers specifically used as a reference for the irradiation, since the markers of the implant screws already anchored in the patient can be used for the same purpose.
  • radiopaque markers are used to plan the therapeutic radiation, each of which is anchored in the patient's body via a screw.
  • the radiopaque markers can then be used in particular to determine a spatial reference system in radiation planning.
  • the method is therefore used in particular for the spatial positioning of patients during medical radiotherapy, whereby in an imaging procedure three or more radiopaque markers are generally used for spatial referencing of a human or animal patient.
  • at least three markers attached to or in the patient's body are used for this purpose so that clear positioning can be carried out.
  • Positioning usually means the patient's actual situation vs. the desired situation, which can be seen from the radiation planning.
  • the three markers can be clearly distinguished from one another in the imaging during radiation.
  • markers are used for radiation planning that are positioned close to, i.e. in the immediate vicinity of, the volume to be irradiated, which is formed by a tumor, for example.
  • Implant screws with markers that are anchored in the spine are particularly suitable for radiation planning in cases where the volume to be irradiated is in the immediate vicinity of the spine or, for example, is located in the abdominal cavity and the spine forms the closest bone structure.
  • radiation planning can be carried out based on the marker(s) of the implant screw(s) in combination with other markers that have been implanted in the patient's body specifically for this purpose, for example.
  • the markers used for radiation planning usually have a defined geometry (e.g. cylindrical, spherical or ring-shaped) and are therefore preferably automatically recognized by the positioning imaging and the planning software.
  • the specified method is preferably automated.
  • the implant screws are preferably pedicle screws, which are advantageously made from a plastic material, in particular fiber-reinforced.
  • Fig. 1 is a schematic view of a medical implant according to the invention in the form of a pedicle system with a plurality of pedicle screws, each implanted in a vertebral body and connected to one another by means of a connecting rod;
  • Fig. 2 is an exploded perspective view of a pedicle screw as well as a tulip head for attachment to a connecting rod and a washer of the implant of Fig. 1;
  • Fig. 3 is a plan view of the screw head of a pedicle screw of the implant of Fig. 1 held in the tulip head;
  • Fig. 4 is a side view of a possible first variant of a pedicle screw of the implant of Fig. 1 held in a tulip head, wherein the area of the screw tip is shown as a central cross-sectional view;
  • Fig. 5 is a side view of a possible second variant of a pedicle screw held in a tulip head of the implant of Fig. 1, wherein the area of the screw tip is shown as a central cross-sectional view;
  • Fig. 6a is a side view of a pedicle screw held in a tulip head with the threaded shaft in a first pivoting state
  • Fig. 6b is a side view of a pedicle screw held in a tulip head with the threaded shaft in a second pivoting state
  • Fig. 7 is a central cross-sectional view of a tulip head of an implant according to the invention with a screwed-on ring marker according to a first embodiment
  • Fig. 8 is a central cross-sectional view of a tulip head of an implant according to the invention with a screwed-on ring marker according to a second embodiment
  • Fig. 9a is a schematic representation of a conical space spanned by the ring marker on the tulip head and another marker on the screw tip of a pedicle screw of one of the implants of Figures 1 to 8;
  • Fig. 9b the same schematic representation as in Fig. 9a, but from a different viewing direction;
  • Fig. 10a is a schematic representation of the dimensions in the direction of the central axis of the tulip head of the pedicle screw of Fig. 9a (x-y plane);
  • Fig. 10b is a schematic representation of the dimensions in the direction perpendicular to the central axis of the tulip head of the pedicle screw of Fig. 9a (y-z plane);
  • Fig. 11 is a schematic representation of the dimensions in any direction to the center axis of the tulip head of the pedicle screw of Fig. 9a;
  • Fig. 12 is a schematic view of a medical implant with a plurality of pedicle screws, each implanted in a vertebral body and having a radiopaque marker, which are used in a method of medical radiotherapy according to the invention as a spatial reference for planning the therapeutic irradiation.
  • Figures 1 to 8 show various embodiments of medical implants according to the invention and parts thereof.
  • Figures 9a to 11 show geometric representations of the markers of these implants and the dimensions resulting from imaging. Elements of different embodiments that have the same or similar effect are each provided with the same reference numeral.
  • Figure 1 shows a preferred embodiment of a medical implant according to the invention in the form of a pedicle system 1.
  • the pedicle system has a plurality of implant screws 4, which can also be referred to as pedicle screws and are each screwed into a vertebral body W of a patient's spine.
  • Each of the implant screws 4 is attached to a connecting rod 3 by means of a tulip head 5.
  • the connecting rod 3 thus connects the implant screws 4 to one another and thereby blocks the vertebral bodies W.
  • the pedicle system 1 can be used, for example, to relieve the intervertebral discs B arranged between the vertebral bodies W.
  • the pedicle system 1 as a whole forms a medical implant 2.
  • a medical implant 2 is also formed by each of the implant screws 4 itself as well as by each common pair of an implant screw 4 and a tulip head 5.
  • a medical implant 2 according to the invention which has an implant screw 4, a tulip head 5 and a washer 6, is shown in Figure 2.
  • the implant screw 4 of this implant 1 has a spherical screw head 41 from which a threaded shaft 43 extends to a screw tip S.
  • the threaded shaft 43 is provided with an external thread which allows the implant screw 4 to be screwed in and anchored in a bone, in particular in a vertebral body, of the patient.
  • the screw head 41 has an engagement structure 42 which has a Torx shape here ( Figure 3) and is used to screw in the implant screw using a suitable tool.
  • a tulip head 5 is used to attach and fix the implant screw 4 shown in Figure 2 to a connecting rod 3, thus forming a fastening element.
  • the tulip head 5 has a rod receiving opening 51 which is open in the longitudinal direction on the side opposite the implant screw 4 and thus allows the connecting rod 3 to be inserted from this side.
  • a clamping part (not shown in the figures) is used to secure the tulip head 5 to the connecting rod 3.
  • This clamping part has an external thread and can be screwed into an internal thread 52 of the tulip head 5.
  • the connecting rod 3 inserted into the rod receiving opening 51 can thus be clamped between the clamping part and the tulip head 5.
  • the implant screw 4 can thus be secured by means of the tulip head 5 and the clamping part can be attached and fixed to the connecting rod 3.
  • the screw head 41 of the implant screw 4 is arranged within the tulip head 5, as is well known from the prior art.
  • the tulip head 5 is designed in two parts with a main part 54, which forms the rod receiving opening 51, and a ring marker 53, which can be screwed onto the main part 54.
  • the screw head 41 of the implant screw 4 is arranged in an area of the tulip head 5 that is delimited by the main part 54 and the ring marker 53.
  • the ring marker 53 is therefore used here in particular for fastening and securing the implant screw 4 to the tulip head 5.
  • the ring marker 53 can therefore also be referred to as a locking ring.
  • a cross-sectional view of the tulip head 5 with the screw-on ring marker 53 is shown in Figure 7.
  • the main part 54 of the tulip head 5 and the ring marker 53 together form an interior provided with rounded boundary surfaces for receiving the screw head 41.
  • the engagement structure 42 is accessible through the tulip head 5 ( Figure 3).
  • the screw head 41 and the threaded shaft 43 are made in one piece and from the same material, whereby the material is a radio-transparent plastic material.
  • a fiber-reinforced composite material such as in particular carbon fiber-reinforced PEEK, is used as the plastic material.
  • the fibers preferably run along the longitudinal direction of the threaded shaft 42 and advantageously have a length that is greater than the longitudinal extent of the implant screw 4.
  • a marker is inserted into the threaded shaft 43, which has a sleeve-like shape here and is therefore referred to as sleeve marker 45.
  • the ring marker 53 and the sleeve marker 45 are made of a material that is significantly more radiopaque than the plastic material of the implant screw 4.
  • CT computer tomography
  • the ring marker 53 and the sleeve marker 45 therefore have a clear contrast to other parts of the implant 2, in particular the screw head 41 and the threaded shaft 43, as well as the surrounding tissue, whereby the ring marker 53 and the sleeve marker 45 are clearly visible in the imaging. are.
  • the markers 53 and 45 which are clearly visible in the images provided, enable the position and orientation of the implant screw 4 in the patient's body to be determined precisely.
  • the tulip head 5 Since the tulip head 5 has the ring marker 53 and this is firmly fixed to the main part 54, the position of the tulip head 5 and the inclination of the implant screw 4 relative to this (and thus to the connecting rod 3) can also be determined using the markers 53 and 45 shown. As can be seen from a combination of Figures 2 and 7, the ring marker 53 is arranged in the fully assembled state such that its ring center corresponds exactly to the center of the spherical screw head 41.
  • the washer 6 When the implant 2 is fully assembled, the washer 6 is arranged between the screw head 41 and the connecting rod 3.
  • the ring-shaped washer 6 can be used to transfer the clamping force from the clamping part to the screw head 41.
  • the connecting rod 3 is then pressed by the clamping part onto the washer 6, which in turn presses the screw head 41 against the ring marker 53 designed as a locking ring.
  • the washer 6 can also be used to decouple the clamping forces caused by the clamping part on the one hand and the ring marker 53 designed as a locking ring on the other, so that the tulip head 5 can be fastened to the connecting rod 3 and to the implant screw 4 independently and with different clamping forces.
  • the clamping part and/or the washer 6 can be made from a radio-transparent plastic material or from a radio-opaque material, for example a metal such as tantalum or titanium. If the clamping part and/or the washer 6 are made from a radio-opaque material, they can contribute to determining the position and location of the implant screw 4 in the imaging process.
  • the main part 54 of the tulip head 5 is preferably made in one piece and from a radio-transparent plastic material, such as carbon fiber reinforced PEEK.
  • Figure 4 shows an embodiment of an implant screw 4 designed as a pedicle screw with a marker inserted into the screw tip S, which is referred to as a ball marker 44 due to its spherical design.
  • the spherical design causes a point-like image of the marker with high contrast in the imaging process.
  • Figure 5 shows a further embodiment which differs from that of Figure 4 in that the implant screw 4 is cannulated, i.e. it has a channel running through the longitudinal direction for supplying medication or bone cement, for example.
  • a sleeve marker 45 is inserted at the screw tip S, instead of a ball marker 44 as in the embodiment of Figure 4.
  • the markers 44 and 45 arranged on the threaded shaft 43 are each arranged directly on the main longitudinal central axis H of the implant screw 4.
  • the ring center formed by the ring marker 53 is located directly on the main longitudinal central axis H.
  • the polyaxial pivotability of the implant screw 4 relative to the tulip head 5 can be seen in Figures 6a and 6b.
  • the pivotability is achieved by the tulip head 5 and the screw head 41 being connected to one another like a ball joint.
  • the tulip head 5 with the connecting rod 3 inserted therein can still be moved when the implant screw 4 is already firmly anchored, i.e. can be pivoted polyaxially relative to the implant screw 4.
  • Only after the clamping part is tightened in a second step is the connecting rod 3 firmly, i.e. immovably, fixed to the implant screw 4 via the tulip head 5.
  • the ring center of the ring marker 53 is arranged inside the screw head 41 after tightening the locking ring formed by the ring marker 53 and even corresponds to its center and thus to the pivot point of the implant screw 4, the position of the implant screw 4 relative to the tulip head 5 and thus to the connecting rod 3 can be intuitively recognized and precisely determined in the imaging process.
  • Figure 7 shows a variant of the tulip head 5 with a screw-on ring marker 53.
  • Figure 8 shows a further variant in which the ring marker 53 is screwed into the main part 54 of the tulip head 5.
  • the ring marker 53 could also be applied in the form of a coating to a one-piece tulip head.
  • Figure 9a shows schematically a circular cone K, spanned by the ring marker 53 arranged on the tulip head 5 and the one on the screw tip S of the implant screw 4 arranged ball or sleeve markers 44 or 45.
  • Figure 9b shows the same circular cone K, but from a different angle than in Figure 9a. Due to the direction of view, it can be seen here that the circular cone K is actually an oblique cone in three-dimensional space, which indicates an inclination of the implant screw 4 relative to the tulip head 5 (e.g. as in Figure 6b).
  • the dashed connecting line in Figures 9a and 9b can be derived, which corresponds to the main longitudinal center axis H of the implant screw 4 and thus indicates the spatial position of the implant screw.
  • the main longitudinal center axis H starting from the screw tip S, always runs centrally through the screw head 41 and through the ring center M of the ring marker 53. The orientation of the implant screw 4 can therefore be clearly determined using the markers.
  • Figure 10a schematically shows the dimensions in the direction of the longitudinal center axis of the tulip head 5 (x-y plane), as they can be presented, for example, in a two-dimensional CT image.
  • the imaging process shows the ring marker 53 with the ring center M and the radius r, as well as the point-like ball marker on the screw tip S.
  • Figure 10b schematically shows the same arrangement as in Figure 10a, but from a different viewing or recording direction, here perpendicular to the longitudinal center axis of the tulip head 5 (y-z plane).
  • the dimensions a and b and the dimensions c and d shown are each perpendicular to one another.
  • the dimensions b and c have the same values.
  • the angle of the main longitudinal central axis H of the implant screw 4 relative to the tulip head 5 can be easily calculated and precisely determined using trigonometric calculations based on the measured distances a, b, c, d, m.
  • the two images can in principle be taken from any direction, but preferably from directions that are 90° different from each other.
  • Figure 11 shows the same illustration as in Figure 10b, with the implant screw 4 showing its However, the inclination relative to the tulip head 5 has changed so that the screw tip S is now arranged at a new position of the screw tip S'.
  • the angle of the main longitudinal central axis H of the implant screw 4 relative to the tulip head 5 can be calculated again using two images and used to verify the stability of the interlock between the tulip head 5 and the implant screw 4.
  • Figure 12 illustrates a method according to the invention for planning radiation in medical radiotherapy based on radio-opaque ball markers 44, each of which is attached to the tip of the threaded shaft 43 of an implant screw 4.
  • the volume to be irradiated is formed here by a tumor T arranged directly on the spine.
  • ball markers 44 these could just as well be sleeve-shaped or any other shaped markers.
  • the radiopaque ball markers 44 can be used in an imaging procedure as a particularly precise and reliable spatial reference for planning the therapeutic radiation.
  • the patient, who already has the implant screws 4, does not have to undergo another medical procedure to insert position markers for the radiation therapy.
  • the ball markers 44 can thus be used to define a spatial three-dimensional reference system x, y, z, with which the position of the area of the body and in particular of the tumor T is determined, which is therapeutically irradiated by means of an irradiation device 7.
  • the ball markers 44 at the tip of the implant screws 4 thus serve as a reference point for positioning the patient for the irradiation and during the "image-guided" radiotherapy. This is made possible in particular by the defined and always consistent geometric shape of the markers. List of reference symbols
  • Implant screw Screw head Vertebral body Intervention structure
  • Intervertebral disc Threaded shaft T
  • Tumor Ball marker Sleeve marker H Main longitudinal central axis

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  • Health & Medical Sciences (AREA)
  • Orthopedic Medicine & Surgery (AREA)
  • Surgery (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Engineering & Computer Science (AREA)
  • Biomedical Technology (AREA)
  • Neurology (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Pathology (AREA)
  • Surgical Instruments (AREA)
  • Prostheses (AREA)

Abstract

L'invention concerne un implant médical (2) avec une vis d'implant (4), en particulier une vis pédiculaire, qui comprend une tête de vis (41) et une tige filetée (43) et qui est produite à partir d'une matière plastique. L'implant (2) comprend des marqueurs radio-opaques (44, 45, 53) afin de permettre une détermination de la position spatiale de la vis d'implant (4) dans le cadre d'un procédé d'imagerie. Dans ce cas, un anneau avec un centre d'anneau (M) agencé à l'intérieur de la tête de vis (41) est formé par l'un des marqueurs (53) ou par une pluralité des marqueurs ensemble, et un autre marqueur (44, 45) est agencé sur ou dans la tige filetée (43). L'invention concerne également un procédé de planification d'irradiation en radiothérapie médicale, dans lequel un ou plusieurs marqueurs radio-opaques (44, 45) agencés sur ou dans la tige filetée (43) d'une vis d'implant (4) ancrée dans le corps sont utilisés pour planifier l'irradiation thérapeutique.
PCT/EP2024/054961 2023-03-20 2024-02-27 Implant médical avec une vis d'implant Pending WO2024193955A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU2024238258A AU2024238258A1 (en) 2023-03-20 2024-02-27 Medical implant with an implant screw

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP23162946.0 2023-03-20
EP23162946 2023-03-20

Publications (1)

Publication Number Publication Date
WO2024193955A1 true WO2024193955A1 (fr) 2024-09-26

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PCT/EP2024/054961 Pending WO2024193955A1 (fr) 2023-03-20 2024-02-27 Implant médical avec une vis d'implant

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AU (1) AU2024238258A1 (fr)
WO (1) WO2024193955A1 (fr)

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4445305C1 (de) 1994-12-19 1996-09-26 Amsler Peter Verfahren zur Herstellung von Bauteilen aus faserverstärkten Thermoplasten sowie nach dem Verfahren hergestellter Bauteil
US20080086129A1 (en) * 2006-09-14 2008-04-10 Warsaw Orthopedic, Inc. Hybrid bone fixation apparatus
US20100042167A1 (en) * 2008-08-13 2010-02-18 Nebosky Paul S Orthopaedic screws
EP2198796A1 (fr) * 2008-12-19 2010-06-23 Sepitec Foundation Vis à os
US20150297267A1 (en) 2010-03-10 2015-10-22 Carbofix In Orthopedics Llc Method of producing an implanatable spinal screw and corresponding spinal fixation system
US10154867B2 (en) 2010-06-07 2018-12-18 Carbofix In Orthopedics Llc Multi-layer composite material bone screw
US10617458B2 (en) 2015-12-23 2020-04-14 Carbofix In Orthopedics Llc Multi-layer composite material bone screw
US20220160400A1 (en) * 2019-03-12 2022-05-26 Carbofix Spine Inc. Composite material spinal implant

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4445305C1 (de) 1994-12-19 1996-09-26 Amsler Peter Verfahren zur Herstellung von Bauteilen aus faserverstärkten Thermoplasten sowie nach dem Verfahren hergestellter Bauteil
US20080086129A1 (en) * 2006-09-14 2008-04-10 Warsaw Orthopedic, Inc. Hybrid bone fixation apparatus
US20100042167A1 (en) * 2008-08-13 2010-02-18 Nebosky Paul S Orthopaedic screws
EP2198796A1 (fr) * 2008-12-19 2010-06-23 Sepitec Foundation Vis à os
US20150297267A1 (en) 2010-03-10 2015-10-22 Carbofix In Orthopedics Llc Method of producing an implanatable spinal screw and corresponding spinal fixation system
US10154867B2 (en) 2010-06-07 2018-12-18 Carbofix In Orthopedics Llc Multi-layer composite material bone screw
US10617458B2 (en) 2015-12-23 2020-04-14 Carbofix In Orthopedics Llc Multi-layer composite material bone screw
US20220160400A1 (en) * 2019-03-12 2022-05-26 Carbofix Spine Inc. Composite material spinal implant

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