Method and apparatus for determining acetabular component positioning

• US 8,267,938 B2
• Filed: 06/06/2008
• Issued: 09/18/2012
• Est. Priority Date: 11/01/2007
• Status: Active Grant

• Current Assignee: M.D. Stephen B. Murphy
• Original Assignee: M.D. Stephen B. Murphy
• Inventors: Murphy, Stephen B.
• Primary Examiner(s): TRUONG, KEVIN THAO
• Application Number:
  US12/134,545
• Publication Number:
  US 20090306679A1
• Time in Patent Office: 1,565 Days
• Field of Search: 606/73, 606/81, 606 86- 91, 606/99, 606/102, 623 1711- 1716, 623 2211- 2237, 600/53, 600/54, 600/63
• US Class Current: 606/91
• CPC Class Codes: A61B 17/00 Surgical instruments, devices or methods, e.g. tourniquets A61B18/00 takes precedence; contraceptive devices, pessaries, or applicators therefor A61F6/00; eye surgery A61F9/007; ear surgery A61F11/00
• CPC Class Codes: A61B 17/17 Guides or aligning means for drills , mills, pins or wires
• CPC Class Codes: A61B 17/1746 for the acetabulum
• CPC Class Codes: A61B 17/56 Surgical instruments or methods for treatment of bones or joints; Devices specially adapted therefor
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2090/067 for measuring angles
• CPC Class Codes: A61B 2090/364 Correlation of different images or relation of image positions in respect to the body
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 5/107 Measuring physical dimensions, e.g. size of the entire body or parts thereof
• CPC Class Codes: A61B 5/1071 measuring angles, e.g. using goniometers A61B5/1123 takes precedence
• CPC Class Codes: A61B 5/1072 measuring distances on the body, e.g. measuring length, height or thickness A61B5/1076 takes precedence
• CPC Class Codes: A61B 5/1114 Tracking parts of the body
• CPC Class Codes: A61B 90/06 Measuring instruments not otherwise provided for
• CPC Class Codes: A61B 90/11 with guides for needles or instruments, e.g. arcuate slides or ball joints
• CPC Class Codes: A61F 2/4609 of acetabular cups
• CPC Class Codes: A61K 2300/00 Mixtures or combinations of active ingredients, wherein at least one active ingredient is fully defined in groups A61K31/00 - A61K41/00
• CPC Class Codes: A61K 31/409 having four such rings, e.g. porphine derivatives, bilirubin, biliverdine hemin, hematin A61K31/555
• CPC Class Codes: A61K 31/44 Non condensed pyridines; Hydrogenated derivatives thereof
• CPC Class Codes: A61K 31/555 containing heavy metals, e.g. hemin, hematin, melarsoprol
• CPC Class Codes: A61K 45/06 Mixtures of active ingredients without chemical characterisation, e.g. antiphlogistics and cardiaca
• CPC Class Codes: B43L 7/10 : Plural straightedges relatively movable
• CPC Class Codes: F16C 11/10 : Arrangements for locking
• CPC Class Codes: F16C 11/103 : frictionally clamped
• CPC Class Codes: F16C 2316/10 : in medical appliances, e.g. in diagnosis, dentistry, instruments, prostheses, medical imaging appliances
• CPC Class Codes: G01B 3/56 : Gauges for measuring angles or tapers, e.g. conical calipers
• CPC Class Codes: G01B 3/563 : Protractors for use in geodesy G01C1/00; protractor heads for drawing machines B43L13/08
• CPC Class Codes: G01B 5/24 : for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: Y10T 403/32426 : Plural distinct positions

Abstract

An instrument for establishing orientation of a pelvic prosthesis comprises a tri-pod having an angularly adjustable guide rod on it. The tips of the legs define a plane, and the guide rod is set by the surgeon to a defined orientation with respect to this plane on the basis of preoperative studies. In use, two of the legs of the instrument are positioned by the surgeon at defined anatomical locations on the pelvis (e.g., a point in the region of the posterior/inferior acetabulum and a point on the anterior superior iliac spine). The third leg then lands on the pelvis at a point determined by the position of the first two points, as well as by the separations between the third leg and the other two legs. The separations are adjustable, but are preferably fixed percentages of the separation between the first and second legs. The position of the guide rod then defines with respect to the actual pelvis the direction for insertion of a prosthesis.

Claims

1. An instrument for establishing a reference plane for a human body structure, comprising a tripod having first, second and third legs for contact with said structure to establish a first reference plane defining the orientation of said structure relative to an independently determined second reference plane associated with said structure, the spacing between at least some of said legs being established at least in part in accordance with anatomical data obtained independently of said instrument.

2. An instrument according to claim 1 in which the spacing between at least a first pair of legs and between a second pair of legs is determined at least in part in accordance with patient-specific data obtained independently of said instrument prior to placing said instrument in contact with said structure for defining the orientation of said structure.

3. An instrument according to claim 1 in which said legs emanate from a central socket in the manner of a camera tripod.

4. An instrument according to claim 1 in which said tripod comprises a frame having first and second arms connected to each other at a central hub, said first and second legs being positioned on said first and second arms, respectively, remote from said hub, and said third leg being positioned at said hub.

5. An instrument according to claim 4 in which said arms are angularly rotatable with respect to each other about said hub.

6. An instrument according to claim 4 in which the length of said arms, and thus the spacing between said first leg and said hub, as well as the spacing between said second leg and said hub, is adjustable.

7. An instrument according to claim 6 in which the spacing between the first and third legs is set to a defined proportion of the distance between the first and second legs.

8. An instrument according to claim 7 in which the spacing between the second and third legs is set to a defined proportion of the distance between the first and second legs.

9. An instrument according to claim 7 in which said proportion is determined in accordance with subject-specific imaging data.

10. An instrument according to claim 9 in which said proportion is determined in accordance with subject-specific imaging data obtained from a CT scan.

11. An instrument according to claim 9 in which said proportion is determined in accordance with subject-specific imaging data obtained from an X-ray.

12. An instrument according to claim 9 in which said proportion is determined in accordance with subject-specific imaging data obtained from one or more X-rays as well as from statistical data defining distance relationships between different locations on human body structures.

13. An instrument according to claim 4 in which one of said legs comprises a hollow conduit for sliding over a rod affixable to the body structure in order to anchor the instrument to said structure.

14. An instrument according to claim 4 in which at least one of said legs is pointed to enable percutaneous placement of said instrument on said body structure.

15. An instrument for establishing a patient-specific hemipelvic reference plane, said instrument comprising a tripod having first, second and third legs for placement on the hemipelvis of a patient to establish a first reference plane defining the orientation of said hemipelvis relative to an independently determined second reference plane associated with said hemipelvis, the spacing between at least some of said legs being established at least in part in accordance with anatomical data obtained independently of said instrument.

16. An instrument according to claim 15 in which said legs are formed to make stable point-contact with three corresponding points on said hemipelvis, said points comprising at least a first point in the region of the posterior inferior acetabulum and a second point in the region of the anterior superior iliac spine.

17. An instrument according to claim 16 in which said tripod comprises a frame having first and second arms connected to each other at a central hub, said first and second legs being positioned on said first and second arms, respectively, remote from said hub, and said third leg being positioned at said hub, the length of said arms, and thus the spacing between said first leg and said hub, as well as the spacing between said second leg and said hub, being adjustable.

18. An instrument according to claim 17 in which the length of at least one of said arms is determined in accordance with subject-specific imaging data.

19. An instrument according to claim 18 in which the length of said at least one arm is determined in accordance with subject-specific imaging data obtained from at least one of a CT image or an X-ray prior to operation on a patient.

20. An instrument according to claim 19 in which the length of said at least one arm is determined at least in part in accordance with statistical data defining distance relationships between different locations on human hemipelvises.

21. An instrument according to claim 18 in which the distance between at least a first pair of legs is set to a defined proportion of the distance between the first and second legs.