EP0554307A1 - Protheses, et procedes et appareil de fabrication de telles protheses - Google Patents

Protheses, et procedes et appareil de fabrication de telles protheses

Info

Publication number
EP0554307A1
EP0554307A1 EP91918498A EP91918498A EP0554307A1 EP 0554307 A1 EP0554307 A1 EP 0554307A1 EP 91918498 A EP91918498 A EP 91918498A EP 91918498 A EP91918498 A EP 91918498A EP 0554307 A1 EP0554307 A1 EP 0554307A1
Authority
EP
European Patent Office
Prior art keywords
prosthesis
bone
plate
prepared
skeletal
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.)
Withdrawn
Application number
EP91918498A
Other languages
German (de)
English (en)
Inventor
Ian Leonard
Raymond Ross
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.)
Individual
Original Assignee
Individual
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 Individual filed Critical Individual
Publication of EP0554307A1 publication Critical patent/EP0554307A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/3094—Designing or manufacturing processes
    • A61F2/30942—Designing or manufacturing processes for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/28—Bones
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30721—Accessories
    • A61F2/30744—End caps, e.g. for closing an endoprosthetic cavity
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/44—Joints for the spine, e.g. vertebrae, spinal discs
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
    • C23F1/00—Etching metallic material by chemical means
    • C23F1/02—Local etching
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/3094—Designing or manufacturing processes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/44—Joints for the spine, e.g. vertebrae, spinal discs
    • A61F2/442—Intervertebral or spinal discs, e.g. resilient
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30535—Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30593—Special structural features of bone or joint prostheses not otherwise provided for hollow
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2002/30001—Additional features of subject-matter classified in A61F2/28, A61F2/30 and subgroups thereof
    • A61F2002/30316—The prosthesis having different structural features at different locations within the same prosthesis; Connections between prosthetic parts; Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30535—Special structural features of bone or joint prostheses not otherwise provided for
    • A61F2002/30604—Special structural features of bone or joint prostheses not otherwise provided for modular
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/30767—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
    • A61F2002/30925—Special external or bone-contacting surface, e.g. coating for improving bone ingrowth etched
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/02—Prostheses implantable into the body
    • A61F2/30—Joints
    • A61F2/3094—Designing or manufacturing processes
    • A61F2/30942—Designing or manufacturing processes for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
    • A61F2002/30952—Designing or manufacturing processes for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques using CAD-CAM techniques or NC-techniques

Definitions

  • This invention relates to prostheses for use in bridging a gap between two bone sections, and methods and apparatus for making such prostheses and surgical technique for bone replacement using such a prostheses.
  • the gap can be filled with bone taken from a rib, thigh, pelvis or other suitable region.
  • This bone can be arranged to fuse with the neighbouring vertebrae as a result of natural bone growth on tc the nucleus afforded by the transferred bone.
  • This-. is an invasive procedure to otherwise healthy bone and surrounding tissue elsewhere and complicates the surgical procedure.
  • the bone is cut and located more or less by guesswork as to an appropriate shape and size, which is not an optimal procedure. It is inappropriate for much more than the replacement of a single vertebra or disc, so that for patients with more exensive damage there is no satisfactory surgical procedure.
  • the invention provides a prosthesis and methods and apparatus for making the same and a surgical technique which facilitates the repair and replacement of vertebrae or discs and also serves for bridging gaps in bones generally.
  • the invention comprises a method for making a prosthesis for use in bridging a gap between two bone sections comprising the steps of a) predetermining the shape of the prosthesis required, and b) preparing a skeletal prosthetic element to the required shape, in such manner as to provide a support in which bone can grow in the gap.
  • the skeletal prosthetic element may be packed with a bone-growth supporting material.
  • the bone-growth supporting material may comprise hydroxy-apatite.
  • the skeletal prosthetic element may comprise any biocompatible material of suitable strength and workability, such for example as metals including stainless steel and titanium.
  • the skeletal prosthetic element may be made by preparing a sheet material plate for plastic deformation to the predetermined shape and plastically deforming said prepared plate to said shape.
  • the plate may be prepared with fold lines which may be made by -etching or, more rapidly, by electro-chemical machining (ECM).
  • the skeletal prosthetic element can be prepared as a strip or plate member from sheet material which can be bent to final shape by the surgeon in the course of the surgical procedure.
  • the production of the bendable plate or strip can be rapidly effected in a variety of ways so that it becomes feasible to manufacture the prosthesis shortly before or even during the procedure to fit precisely the prosthetic site.
  • the plate When the plate is prepared by etching or ECM, other features may be produced together with the fold lines, for example attachment spikes for engaging the prosthesis with neighbouring bone, and apertures for screws and pins, and the required perimeter of the prosthesis may also be produced by through-etching or ECM on the plate.
  • the plate may be prepared for etching or ECM by removing a resist layer; such layer may be removed mechanically as by a blade or rotary tool, or by an ultrasonic tool, or it may be removed by vaporisation as by an electrical discharge or laser.
  • the resist layer may also be removed by selectively applying a chemical reagent or solvent.
  • the plate may be etched on both faces, for example for etching-through for perimeter-definition and for making spikes, screw holes and the like. Screws and/or pin apertures or holes may also be produced by a drill or punch or other purely mechanical means where convenient.
  • the etched or ECM-produced plate may be electropolished to remove sharp ridges or burrs.
  • the skeletal prosthetic element may be prepared by numerically-controlled tool means, which may operate in an etching or ECM process to prepare the plate for etching or ECM by selectively removing a resist layer, or which may operate directly on the plate to remove material therefrom as by drilling, routing etc.
  • the skeletal prosthetic element may be prepared according to instructions derived from a programmed computer supplied with data specifying the shape of prosthesis required, and such computer may control the preparation of a plate from which the skeletal prosthetic element can be fashioned by bending along fold lines.
  • the computer may include CAD facility, in which X-ray photographs of the prosthesis site may be used.
  • Another technique involves interposing an apertured non-conducting layer e.g. of plastic sheet between the electrode and the workpiece.
  • the apertures may be made by a rotating tool, a laser, an ultrasonic cutter or in any other convenient manner.
  • the skeletal prosthetic element may be assembled from a plurality of sub-elements, and may be assembled from anchor plates and a spacer member joining the anchor plates and formed from a folded plate or plates.
  • the spacer member may be cruciform and comprise meshing plates into which a bone growth supporting material, such as hydroxy-apatite, may be introduced into the prosthetic site; and final shaping and assembly may take place during surgical procedures.
  • the invention also comprises apparatus for making a prosthesis for use in bridging a gap between two bone sections at a prosthetic site comprising, in combination a) means for predetermining the shape of the prosthesis required for the site, and b) sheet material plate preparation means for preparing such plate for plastic deformation to a skeletal prosthetic element, in such manner as to provide a support in which bone can grow in the gap.
  • the sheet material preparation means may comprise etching or electro-chemical machining means, and may also comprise electropolishing means.
  • the preparation means may be numerically controlled and may comprise CAD means providing instructions for the preparation means, which may in turn comprise information input means for example for information derived from X-ray photographs.
  • the invention also comprises a novel prosthesis for use in bridging a gap between two bone sections comprising a skeletal prosthetic element adapted tc the prosthetic site and capable of providing a support in which bone can grow in the gap.
  • the element may be packed with a bone-growth supporting material, such as hydroxy-apatite.
  • the novel prosthesis may comprise folded sheet material, and may comprise attachment spikes adapted to engage bone either side of the gap.
  • a surgical technique using prostheses according to he invention can ensure safe repeatable results for both disc and complete vertebra replacement.
  • Figure 2 is a top view of the prosthesis of Figure 1;
  • Figure 3 is a view of the top (a) and bottom (b) sections of the prosthesis of Figure 1 presented for engagement together;
  • Figure 4 is a side view of the top anchor plate of a vertebrate body replacement prosthesis
  • FIG. 5 is a side view of a cage member for use with the top anchor plate of Figure 4;
  • Figure 6 is a side view of a bottom anchor plate to fit the cage member of Figure 5;
  • Figure 7 is a plan view of an etched plate from which the anchor plates of the prosthesis of Figures 4 and 6 are produced?
  • Figure 8 is a plan view of an etched plate from which the cage member of Figure 5 is produced;
  • Figure 9 is a cross-sectional view of alternative cage members
  • Figure 10 is a view of an etched or ECM blank for another type of bone replacement prosthesis
  • Figure 11 is a view of the prosthesis made by bending the blank of Figure 10;
  • Figure 12 is a section on the line XII-XII of Figure 11;
  • Figure 13 is a section on the line XIII-XIII of Figure 11;
  • Figure 14 is a front and back side-on view of a swage tool
  • Figure 15 is a diagrammatic illustration of a locking procedure carried out by the swage tool of Figure 14;
  • Figure 16 is a diagrammatic illustration of a CAD/CAM system for producing prepared sheet material plate ready for etching to produce the prostheses of Figure 1 to 11;
  • Figure 17 is a block diagram of a method for making the prostheses from the etched or electro-che ically machined plates of Figure 18;
  • Figure 18 to 20 are diagrammatic illustrations of electro-chemical machining techniques
  • Figure 21 is a block diagram of a method for the production of a prosthesis ready for implantation from the prepared plate using the electro-chemical machining techniques of Figures 19 to 20.
  • Figure 22 to 37 are diagrammatic illustrations of sequential steps in a surgical technique for replacement of diseased vertebrate bodies with metal vertebra prostheses prepared as described in Figures 4 to 9.
  • the production of shaped articles from thin metal plates by etching fold lines and other features is already known, but as currently practised does not lend itself to rapid custom production.
  • the resists in common use are photographic and the etching pattern is produced by photographing a master drawing, usually involving a reduction of scale so that high accuracy can be achieved. It is not economical to use this process to produce articles on a one-off basis and it would in any event be difficult to complete a 15 x 5 cm component from concept to finished state in less than five hours, even if the production were to be given priority and undivided attention.
  • two o three days at least are required if the procedure is to fit within any ordered, commercial production schedule.
  • Photographic techniques may of course be developed in the future which will reduce the time and cost. Meanwhile, however, etched plates can be produced by other methods which do not suffer the disadvantages of the current photographic techniques.
  • Figures 1 to 3 illustrate a prosthesis 111 for use in bridging a gap between two bone sections, such for example as will occur when a vertebrate disc is removed.
  • Figures 4 to 9 illustrate prostheses 211 for use in bridging a gap between two bone sections, such for example as will occur when a vertebrate body is removed.
  • the disc prosthesis 111 comprises two skeletal prosthetic elements 112a and 112b made of stainless steel or titanium in which may be packed a bone-growth supporting material such as hydroxy-apatite (not shown) .
  • the upper plate 112a and lower plate 112b connect together by pop rivets through holes 114 (or by swage locking by tools as shown in Figures 14 and 15 and described below) on adjacent overlapping edges 115,116 and by flaps 118 on one edge of upper or lower plates wrapping around edges 119 on adjacent upper and lower plates.
  • Both upper and lower plates have V-notches 117 for engaging the bone sections either side of the disc to be replaced. Both upper and lower plates are engaged to the vertebrae by screws 117a through holes 120 in the notches 117.
  • each plate 112a,112b is determined by through-etching or ECM in a larger plate. Etching burrs are removed by electro polishing.
  • the vertebra prostheses 211 of Figures 4 to 9 comprise anchor plates 214a which have a pentagonal protrusion 215 for engaging the bone sections either side of the gap, and a spacer or connecting member 216 joining the anchor plates 214b.
  • the spacer member 213 is formed from a single plate of sheet material which is bent into a closed loop and has tabs 217 by which it is clipped together to fit the anchor plates 214 and secured thereto by pop rivets through holes 218 located on upper and lower flaps of anchor plates 214, and upper and lower edges of spacer member 216 or swage locked as described below.
  • the member also has spikes 219 which can penetrate into bone either side of the gap to secure the prosthesis in place. Additional spikes could however be provided on the anchor plates.
  • the anchor plates 214 and the spacer member 213 are made from sheet material such as stainless steel or titanium by etching or ECM.
  • Figures 7 and 8 show etched plates 241 and 251 respectively from which the anchor plates 214 and the spacer member 213 can be produced by suitable folding or bending.
  • the plate 241 is etched with fold lines 242 and etched-through lines 243.
  • Pentagonal protrusion 215 is formed by bending the pentangular portions 244 out of the plane of the Dlate on the fold lines 242. Aoertures for through spikes 219 are made by etching out the portions 245.
  • the plate 251 is formed with fold lines 252,253.
  • each plate 241 and 251 is determined by through-etching in a larger plate. Etching burrs are removed by electropolishing.
  • the spacer member 213 is bent from the plate 251 along the fold lines 252 and assembled to fit anchor plate 214 by fitting the tabs 217 through the apertures therein and folding them about the fold lines 253. Not all the tabs and corresponding apertures are shown.
  • the prosthesis is then secured by fastening the anchor plates 214 to the spacer member 213 by pop rivets or swaging through holes 218 as described below.
  • the prostheses of Figures 1 to 3 and 4 to 7 are intended to be packed with pieces or sticks of hydroxy-apatite 216 prior to closing up the assembly.
  • the result is a strong, rigid prosthesis that can be fixed by the pentagonal protrusions 215 into the neighbouring bone sections to bridge the gap between them and provide a nucleus for bone growth to consolidate the bridge.
  • Figure 9 shows alternative vertebrate sections 261,262,263 merely to indicate that the surgeon has some degree of latitude in the precise configuration of the prostheses to accommodate different details of individual vertebra through the length of the spinal column.
  • prostheses as illustrated in Figures 1 to 3 and 4 to 9 are intended to exemplify the constructional method rather than the actual shape and configuration of prostheses which will in fact be used in surgical procedures.
  • a prosthesis is intended to replace a disc or a vertebra, it will in general resemble the disc or vertebra it is intended to replace.
  • a suitable swage tool 23 is shown in Figure 14 and has a flared head which is oblong or oval in cross section.
  • Figure 15 illustrates a different type of prosthesis suitable for bridging long bones where material has been removed.
  • Figure 10 is a fiat processed etched or ECM blank 101 of stainless steel or titanium ready for bending to the cylindrical shape of Figure 11, Figures 12 and 13 being cross sections on the lines XII-XII and XIII-XIII respectively.
  • the blank 101 is formed with upper and lower double rows of screw holes 102 through which small screws secure the prosthesis to the bone sections to be bridged.
  • the upper and lower edges are shaped around the holes 102 to provide some flexibility, the shaping being "wavy" rather than have sharp corners.
  • Fold lines 103 run from upper to lower edge between panels 104 which are apertured by through cuts 105 and fold lines 106 so that panels 105a can be bent in towards the middle of the prosthesis when it is formed from the blank 101, thus creating a stiff structure of greater strength than the bone.
  • the inner edges 105b of the panels 105a provide line supports for a hydroxy-apatite insert 107 ( Figure 12).
  • prostheses of the same general shape and configuration as the illustrated prostheses could be produced in many different ways, it is desirable, according to the present invention, to make them in such a way that they can be custom-made shortly before or even during the course of the surgical procedure in which they will be used.
  • the illustrated prostheses are for this reason fabricated from plates of sheet material of stainless steel or titanium by an etching or ECM process in which fold lines are introduced on which the sheet can be bent into the required three-dimensional shape. No machining is needed in this operation, nor any special tools, except possibly for pliers to help in the bending operations where small parts such as spikes and tabs are involved.
  • a light-box 85 is provided to illuminate an X-ray photograph 86 which can be viewed with a CCD camera 87 to produce an image on the screen 82 around which the prosthesis can be sketched using the lights, magnetic or inductive pen 83.
  • Software can, however, also be provided to analyse X-ray images taken from different angles to provide information from which a three-dimensional representation of the fracture site can be computed and from which, in turn, the required prosthesis shape can also be worked out according to algorithms, which might be compiled initially using an expert system, for example.
  • Software can also be provided then to calculate the size of blank required and to specify the fold lines and other features required to be marked to prepare the blank for etching or ECM so that it will deform into the required shape.
  • marking is meant, of course, the removal or modification of a resist, which may be a wax coating or a rubber or plastic film adhered to the metal surface to allow an etchant or electrolyte access to the metal at the marked places.
  • the computer can then control the operation of an X-Y plotter 88 equipped with a tool 89 for marking the blank 51.
  • the tool 89 can be a blade or a rotary tool, for example a miniature air driven router, or a laser or electric discharge device to melt or vaporize a resist, or a pen or jet printer or air brush applying a reagent or solvent.
  • the marked blank is then subject to the sequence of operations indicated in Figure 17, namely it is first of all etched or electrochemically machined, then rinsed, then the remaining resist is removed, following which it is re-etched or electro- polished to remove sharp burrs left by the etching process, after which it is again rinsed.
  • the thus prepared plate is now plastically deformed, by hand bending on the fold lines, to its final shape as dictated by the fold lines, following which it is autoclaved to sterilize it ready for use.
  • Figure 18 shows diagramatically a method of electrochemical machining (ECM).
  • ECM electrochemical machining
  • the said metal blank 93 and metal electrode 91 are connected to a source of direct current. Arcing is prevented by circulating an electrolyte 96, for example an hydroxide or ionised salt, or a conductive acid such as nitric or sulphuric, between the electrodes. Metal ions are taken into the electrolyte from the blank where the resist layer has been removed creating an etching 98 of the required dimensions.
  • an electrolyte 96 for example an hydroxide or ionised salt, or a conductive acid such as nitric or sulphuric
  • the metal blank 93 is rinsed and the remaining resist coating is removed before electro polishing and the other steps in Figure 17 to achieve a complete prosthesis.
  • Figures 19 and 20 A different approach is shown in Figures 19 and 20.
  • the metal blank 93 anode
  • the resist coating 94 with marked etching pattern 95 is located on the solid metal electrode 91 (cathode).
  • a current passes between the two electrodes as an electrolytic solution 96 flows there ⁇ between to create an etching 98 in the metal blank 93.
  • Figure 20 shows a further different approach in which a non-conducting plastic sheet 92 is interposed between the blank 93 and the electrode 91, close to the blank.
  • the sheet 92 is apertured as would be a resist, by routing, laser or otherwise. It may not always be necessary to circulate the electrolyte using this technique.
  • An advantage of the improved method described with reference to Figures 19 and 20, which is made clear in Figure 21, is further time saving, since the metal blank is not coated in resist, therefore the time-consuming step of resist removal after etching is avoided.
  • etching or ECM need not be the method of preparation - the plate could be machined by conventional metal processing methods for example using a CAM technique based on the X-Y table such as mechanical, grinding, laser or other cutting tools to produce the fold lines and other features.
  • a CAM technique based on the X-Y table
  • these would require stronger machine tool type equipment to resist cutting forces and ensure accuracy; need change tools to produce lines and holes - an expense and sophistication not suitable to the medical environment which this invention will overcome.
  • plastics materials for example, they may be selectively modified otherwise than by etching or cutting, as by UV illumination, low power laser, ultrasonic horn or isotope radiation so as to cause shrinkage along lines on one face or the other that would bring about the required deformation.
  • the diseased vertebrate body 191 is first exposed, together with adjacent discs 191a,191b and vertebrae, by surgery ( Figure 22).
  • a pilot hole is drilled in the healthy vertebra 191b, directly above the said diseased vertebra ( Figure 23) and a circular piece of bone 192 cut out to a specific depth.
  • a second pilot hole 193 is drilled in the healthy vertebra, 191c, using jig 190, directly below the said diseased vertebrate body, and a circular piece of bone 194 similarly cut out to a specific depth (Figure 24).
  • the next procedure involves locating a clamp frame 196 into the top and bottom of holes 195 with hemispherical strips 199 and securing the frame 196 by compressing locking screws 198 into the healthy vertebrate bodies either side of the diseased vertebra ( Figure 26) .
  • the anchor plate 214a is then screwed into the upper vertebrate body 203 by screw pins 205.
  • Figure 30 shows the steps in Figure 29 repeated for the lower prosthesis anchor plate 214b positioned into the lower vertebrate body 206 by sliding the pentagonal protrusion 215b into the bevelled hole 195b and securing by screws 208.
  • a column jack 209 is inserted into the said metal pentagonal protrusions and tensioned to enable the upper prosthesis anchor plate to be undamped by releasing screws 198.
  • the vertebra are then jacked apart ( Figure 32) by approximately 2 mm, 200, and the spacer member 213 inserted between the two prosthesis anchor plates. At this point, the member 213 is only partially closed up so that access can be had to its interior.
  • the jack 209 is retracted to original length 200 and the spike projections 219 (see Figure 5) are thus driven into the vertebra ( Figure 33).
  • the frame clamp screws 198 of the upper clamp 196 are then recompressed and the jack removed.
  • the clamp frame 196 is removed by unscrewing clamp screws 198.
  • top and bottom pentagonal protrusions are filled with hydroxy-apaptite 224 and the hole tabs 244 closed ( Figure 37).
  • the fully fastened anchor plates and spacer member now form the finished replacement vertebrate prosthesis.
  • the diseased vertebra has now been completely replaced by a metal replacement vertebra prosthesis in a safe repeatable manner and it remains only to close up.
  • the modofied surgical procedure (based on that outlined above) can be carried out using, instead of the replacement vertebra prosthesis described in Figures 4 to 9, the disc replacement prosthesis described in Figures 1 to 3.

Abstract

Une prothèse (111, 112) utilisée pour relier deux parties osseuses par-dessus un vide, par exemple pour remplacer une vertèbre malade ou un disque, comprend un élément prothétique squelettique (213, 214) pouvant s'adapter au site de la prothèse de manière à produire un support sur lequel l'os peut pousser par-dessus le vide. Le support (213, 214) peut être rempli d'un matériau de support de croissance osseuse tel que l'hydroxyapatite. L'élément (213, 214) peut être fabriqué selon des techniques CAO/FAO et par un procédé consistant à graver ou à usiner de manière électrochimique des lignes de pliures (242, 252, 253) dans une plaque metallique profilée de la manière requise par déformation plastique, de sorte qu'il peut être fabriqué sur mesure sur les lieux de l'opération et au cours de celle-ci par un appareil de CAO/FAO combiné avec un équipement de gravure ou d'usinage électrochimique.
EP91918498A 1990-10-23 1991-10-22 Protheses, et procedes et appareil de fabrication de telles protheses Withdrawn EP0554307A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB9022996 1990-10-23
GB909022996A GB9022996D0 (en) 1990-10-23 1990-10-23 Prosthesis and methods and apparatus for making same

Publications (1)

Publication Number Publication Date
EP0554307A1 true EP0554307A1 (fr) 1993-08-11

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Application Number Title Priority Date Filing Date
EP91918498A Withdrawn EP0554307A1 (fr) 1990-10-23 1991-10-22 Protheses, et procedes et appareil de fabrication de telles protheses

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EP (1) EP0554307A1 (fr)
JP (1) JPH06504213A (fr)
AU (1) AU8857591A (fr)
GB (1) GB9022996D0 (fr)
WO (1) WO1992006654A1 (fr)

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4409836A1 (de) * 1994-03-22 1995-09-28 Draenert Klaus Vorrichtung zum mechanischen Schutz eines Implantats oder Transplantats beim Einführen in einen und/oder Verbleiben in einem lebenden Körper
EP1818025A3 (fr) * 1996-02-19 2007-12-05 Warsaw Orthopedic, Inc. Implants pour fusion rachidienne et outils pour leur insertion et révision
GB2338652A (en) * 1998-06-23 1999-12-29 Biomet Merck Ltd Vertebral body replacement
US7172814B2 (en) 2003-06-03 2007-02-06 Bio-Tec Biologische Naturverpackungen Gmbh & Co Fibrous sheets coated or impregnated with biodegradable polymers or polymers blends
DE102007011632B3 (de) * 2007-03-09 2008-06-26 Poligrat Gmbh Elektropolierverfahren für Titan
CN105748177B (zh) * 2016-04-20 2018-01-02 华南理工大学 一种个性化具有仿生微孔的脊椎植入假体及其制造方法

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US4501269A (en) * 1981-12-11 1985-02-26 Washington State University Research Foundation, Inc. Process for fusing bone joints
EP0176728B1 (fr) * 1984-09-04 1989-07-26 Humboldt-Universität zu Berlin Prothèse pour disques intervertébraux
GB8510621D0 (en) * 1985-04-26 1985-06-05 Pickering Electronics Ltd Potted electronic components
DE3522196A1 (de) * 1985-06-21 1986-02-20 Martin Wilhelm Dr. Dr. 6072 Dreieich Happel Verfahren zur fertigung von gelenkendoprothesen und osteosynthesematerial oder anderem knochenersatz nach den knochendimensionen des patienten
GB8516582D0 (en) * 1985-07-01 1985-08-07 Univ London Forming prostheses/orthoses
FI81010C (fi) * 1986-09-05 1990-09-10 Biocon Oy Stoedstruktur foer bentransplantat.
DE3716026A1 (de) * 1987-05-14 1988-12-01 S & G Implants Gmbh Verfahren zur herstellung einer gelenkendoprothese
FR2627978B1 (fr) * 1988-03-04 1997-06-13 Cessot Christian Dispositif de reproduction de relief osseux par echographie ultrasonore tridimensionnelle
WO1989011257A1 (fr) * 1988-05-23 1989-11-30 Augspurger Lynn L Procede et systeme de fabrication de dispositif prothetique
CA1333209C (fr) * 1988-06-28 1994-11-29 Gary Karlin Michelson Implants artificiels pour la soudure osseuse intervertebrale

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Title
See references of WO9206654A1 *

Also Published As

Publication number Publication date
JPH06504213A (ja) 1994-05-19
WO1992006654A1 (fr) 1992-04-30
AU8857591A (en) 1992-05-20
GB9022996D0 (en) 1990-12-05

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