Method of forming a temporary implant

• US 7,867,426 B2
• Filed: 03/12/2007
• Issued: 01/11/2011
• Est. Priority Date: 03/23/2006
• Status: Expired due to Fees

• Current Assignee: Bruce H. Ziran, Joseph W. Whiteside
• Original Assignee: Bruce H. Ziran, Joseph W. Whiteside
• Inventors: Whiteside, Joseph W., Ziran, Bruce H.
• Primary Examiner(s): Del Sole; Joseph S
• Assistant Examiner(s): Robitaille; John P
• Application Number:
  US11/716,757
• Publication Number:
  US 20070222114A1
• Time in Patent Office: 1,401 Days
• Field of Search: 264/279, 623/901, 249/61, 249/55, 249/141, 249/168
• US Class Current: 264/279
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30354 Cylindrically-shaped protrusion and recess, e.g. cylinder of circular basis
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30616 Sets comprising a plurality of prosthetic parts of different sizes or orientations
• CPC Class Codes: A61F 2002/30672 temporary
• CPC Class Codes: A61F 2002/30677 Means for introducing or releasing pharmaceutical products, e.g. antibiotics, into the body
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3625 Necks
• CPC Class Codes: A61F 2002/365 Connections of heads to necks
• CPC Class Codes: A61F 2002/3652 Connections of necks to shafts
• CPC Class Codes: A61F 2220/0033 made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2310/00353 Bone cement, e.g. polymethylmethacrylate or PMMA
• CPC Class Codes: B29C 39/021 by casting in several steps
• CPC Class Codes: B29C 39/10 : incorporating preformed parts or layers, e.g. casting around inserts or for coating articles coating a surface by casting in general B05D1/30, B29C39/126 takes precedence
• CPC Class Codes: B29C 39/26 : Moulds or cores
• CPC Class Codes: B29L 2031/7532 : Artificial members, protheses
• CPC Class Codes: Y10S 623/901 : Method of manufacturing prosthetic device

Abstract

A mold assembly and method of forming a surgical implant from bone cement. The method has the steps of connecting a plurality of mold segments to approximate the size of a patient implant. Each mold segment has an open channel. The method may further include aligning the channels of connected mold segments, positioning a centralizing holder on a reinforcement member, mixing bone cement, pouring at least some bone cement through the channels and into connected mold segments, fitting the reinforcement member into the mold segments, curing the bone cement; and removing the cured surgical implant.

Claims

1. A method of forming for a patient an adjustable length, surgical implant made from a bone cement, said method comprising:

(a) connecting three or more disposable mold segments to approximate the length of surgical implant needed for the patient, each mold segment being made from an opaque material and having an elongated channel through which the bone cement will be fed and an implant reinforcement member will be inserted after partial mold filling with the bone cement;

(b) aligning the elongated channels of adjacent connected mold segments;

(c) positioning at least one mold centralizer on the reinforcement member sized for fitting within the connected mold segments;

(d) mixing the bone cement;

(e) pouring a first quantity of the bone cement through the aligned, elongated channels of and into the connected mold segments;

(f) fitting the reinforcement member and mold centralizer through the aligned, elongated channels for substantially centering the reinforcement member within the connected mold segments before they are completely filled with the bone cement and fully encompass the reinforcement member therein;

(g) pouring a second quantity of the bone cement about the reinforcement member to substantially fill the connected mold segments;

(h) curing the bone cement; and

(i) removing the mold segments from about the cured bone cement to form the surgical implant that was adjusted in length for the patient.

2. The method of claim 1 which further comprises adding antibiotic to the bone cement during the mixing step.

3. The method of claim 1 which further comprises loading the bone cement in an applicator after the mixing step.

4. The method of claim 1, wherein certain areas of said mold segments include a plurality of apertures through which excess bone cement will pass for indicating substantial filling of those mold segment areas.

5. The method of claim 1, wherein removing step (i) comprises:

cutting the mold segments away from the surgical implant.

6. The method of claim 1 which further comprises positioning connected mold segments in a holding apparatus before the first pouring step.

7. The method of claim 1, wherein the implant is used for replacing an articular joint in the patient.

8. The method of claim 1, wherein the implant is used for replacing one or more hip, knee, leg or ankle bones in a patient.

9. The method of claim 4 which further comprises removing excess bone cement that has passed through the mold segment apertures.

10. The method of claim 5, wherein an exterior of one or more mold segments is pre-scored.

11. The method of claim 6, wherein the holding apparatus comprises vacuum extraction packing and an insulated cover.

14. The method of claim 2, wherein at least some of the mold segment exteriors are pre-scored.

12. A method of forming an articular joint implant customized in length for a patient, said articular joint implant being made from a mixture of bone cement with one or more antibiotics, said method comprising:

(a) interconnecting appropriate lengths of opaque mold segments to approximate the length of articular joint implant needed for the patient, at least some of said opaque mold segments having;

(i) a slotted channel through which the mixture will be fed and through which a central reinforcement member will be inserted after the opaque mold segments are partially filled with the mixture; and

(ii) a plurality of apertures through which excess mixture will pass for indicating sufficient mixture filling into that opaque mold segment;

(b) aligning the slotted channels of adjacent opaque mold segments;

(c) positioning a plurality of mold spacers on the reinforcement member;

(d) inserting the reinforcement member through the aligned slotted channels and into the connected opaque mold segments;

(e) making the mixture of bone cement with one or more antibiotics;

(f) holding the connected opaque mold segments substantially level in a holding apparatus;

(g) pouring the mixture through the slotted channels and into the connected opaque mold segments until excess mixture has passed through a sufficient quantity of the mold segment apertures;

(h) curing the mixture within the connected opaque mold segments; and

(i) removing the connected opaque mold segments from about the cured mixture to form the articular joint implant customized in length for the patient.

13. The method of claim 12, wherein the articular joint implant is selected from the group consisting of a hip, knee, leg or ankle bone.