METHOD AND APPARATUS FOR DETERMINING ACETABULAR COMPONENT POSITIONING

• US 20090306679A1
• Filed: 06/06/2008
• Published: 12/10/2009
• 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.
• Granted Patent: US 8,267,938 B2
• Time in Patent Office: Days
• US Class Current: 606/130
• 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. Apparatus for orienting a surgical instrument, comprising:

a frame having at least three legs for placement on a subject to define a reference plane relative to the subject; and

a guide positionable on said frame to define an orientation with respect to said frame.

2. Apparatus according to claim 1 in which the distance between at least two of said legs is adjustable.

3. Apparatus according to claim 2 in which the distance between at least three of said legs is adjustable.

4. Apparatus according to either claim 2 or 3 in which the angular orientation between a first and a second pair of legs is adjustable.

5. Apparatus according to claim 1 in which said guide is mountable on said frame and is adjustable in angular orientation with respect to a plane defined by the legs of said frame.

6. Apparatus according to either claim 1 or claim 5 in which said guide comprises a hollow tube.

7. Apparatus according to claim 6 which includes a hollow tube parallel to said guide which accommodates an elongated pin insertable into a subject through said tube at a location determined by the surgeon.

8. Apparatus according to claim 6 in which said guide accommodates an elongated pin insertable into a subject through said tube.

9. Apparatus according to claim 1 in which the legs of the apparatus are adjustable such that, when a first of said legs is positioned in the area of the posterior inferior acetabulum of said subject and a second of said legs is positioned in the area of the anterior superior iliac spine of said subject, said third leg is thereby positioned on the ilium of said subject to thereby define a plane with respect to which said surgical instrument may be oriented.

10. Apparatus according to claim 9 in which said legs are adjustable such that the distance between at least one pair of said legs is adjustable to be a proportion of the distance between another pair of said legs.

11. Apparatus according to claim 10 in which said proportion is on the order of between 70% and 100%.

12. Apparatus according to claim 10 in which said proportion is on the order of between 90%.

13. Apparatus according to claim 11 in which said proportion is determined in accordance with subject-specific data obtained from a CT scan.

14. Apparatus according to claim 11 in which said proportion is determined in accordance with subject-specific data obtained from an X-ray.

15. Apparatus according to claim 11 in which said proportion is determined in accordance with a combination of subject-specific data obtained from an X-ray and statistical data defining distance relationships between the acetabulum and locations on the ischium.

16. A method for orienting a surgical instrument with respect to the pelvis of a subject, comprising:

placing a first leg of a tripod in the area of the posterior inferior acetabulum of said subject;

placing a second leg of the tripod in the area of the anterior superior iliac spine of said subject; and

placing a third leg of the tripod on the ilium of said subject,

the ends of the legs in contact with the subject thereby defining a plane with respect to which said instrument may be oriented.

17. A method according to claim 16 in which said first leg is placed proximate to, and outside of, the acetabular rim.

18. A method according to claim 17 in which said legs are separated by defined distances relative to each other.

19. A method according to claim 18 in which the distance between said first and third legs is adjusted to be a defined proportion of the distance between said first and second legs.

20. A method according to claim 19 in which said proportion is determined in accordance with subject-specific data obtained from a CT scan.

21. A method according to claim 19 in which said proportion is determined in accordance with subject-specific data obtained from an X-ray.

22. A method according to claim 19 in which said proportion is determined in accordance with a combination of subject-specific data obtained from an X-ray and statistical data defining distance relationships between the acetabulum and locations on the ischium.

23. A method for registering a surgical navigation system with respect to a subject, comprising:

placing a first leg of a tripod in the area of the posterior inferior acetabulum of a subject;

placing a second leg of the tripod in the area of the anterior superior iliac spine of said subject; and

placing a third leg of the tripod on the ilium of said subject,

the ends of the legs in contact with the subject thereby defining a plane with respect to which said navigation system may be oriented.

24. A method according to claim 23 which further includes the step of determining the orientation of said navigation system to said plane in accordance with subject-specific data obtained from a CT scan.

25. A method according to claim 23 which further includes the step of determining the orientation of said navigation system to said plane in accordance with subject-specific data obtained from an X-ray scan.

26. A method according to claim 23 which further includes the step of determining the orientation of said navigation system to said plane in accordance with a combination of subject-specific data obtained from an X-ray and statistical data defining an estimate of the three dimensional surface structure of the hemipelvis and pelvis.

27. A method for registering a surgical navigation system with respect to a subject, comprising:

registering a first point in the area of the posterior inferior acetabulum of a subject;

registering a second point in the area of the anterior superior iliac spine of said subject; and

registering a third point on the ilium of said subject,

said points defining a plane with respect to which said navigation system may be oriented.

28. A method according to claim 27 which further includes the step of determining the orientation of said navigation system with respect to said plane in accordance with subject-specific data obtained from a CT scan.

29. A method according to claim 27 which further includes the step of determining the orientation of said navigation system with respect to said plane in accordance with subject-specific data obtained from an X-ray scan.

30. A method according to claim 27 which further includes the step of determining the orientation of said navigation system with respect to said plane in accordance with a combination of subject-specific data obtained from an X-ray and statistical data defining an estimate of the three dimensional surface structure of the hemipelvis and pelvis.

31. A method for registering a surgical navigation system with respect to a subject, comprising a virtual instrument

wherein the first of three or more points is digitized in the area of the posterior inferior acetabulum of a subject;

the second point is digitized in the area of the anterior superior iliac spine of said subject at a predetermined distance from the first point; and

the third point is digitized in a location that is on the bone surface, a specified distance from the 1^st point, and a specified distance from the second point of said subject,

these three points digitized on the subject thereby defining a plane with respect to which said navigation system may be oriented.

32. A method according to claim 31 which further includes the step of determining the orientation of said navigation system with respect to said plane in accordance with subject-specific data obtained from a CT scan.

33. A method according to claim 31 which further includes the step of determining the orientation of said navigation system with respect to said plane in accordance with subject-specific data obtained from an X-ray scan.

34. A method according to claim 31 which further includes the step of determining the orientation of said navigation system with respect to said plane in accordance with a combination of subject-specific data obtained from an X-ray and statistical data defining an estimate of the three dimensional surface structure of the hemipelvis and pelvis.