Three-dimensional in-vitro spinal models and methods of analyzing substance distribution therein

• US 20050106545A1
• Filed: 10/01/2004
• Published: 05/19/2005
• Est. Priority Date: 10/03/2003
• Status: Active Grant

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Hegland, Michael, Heruth, Kenneth T., Lent, Mark S.
• Granted Patent: US 7,403,883 B2
• Time in Patent Office: Days
• US Class Current: 434/267
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: G09B 23/30 Anatomical models G09B23/281 - G09B23/288 take precedence
• CPC Class Codes: G09B 23/34 with removable parts

Abstract

An in-vitro model apparatus of a human spine and methods for detecting and analyzing substance distribution patterns therein. In one embodiment, the model apparatus includes a column body defining a passageway that substantially mimics the size, shape, and structure of an adult human spinal canal. Also included is a cord structure that may be located and anchored within the passageway. The cord structure substantially mimics the size, shape, and structure of an adult human spinal cord. For example, the cord structure may include connecting elements that resemble nerve roots, dentate ligaments, and the septum posticum of a human spine. The passageway of the model apparatus may be filled with a first fluid that simulates cerebro-spinal fluid (CSF), and a second fluid containing a drug (or simulated drug) may be introduced into the passageway, after which the drug'"'"'s distribution within the passageway may be analyzed.

Claims

1. A three-dimensional in-vitro model apparatus of a human spine comprising:

a model body comprising a column portion, the column portion defining a curved passageway in the shape of a human spinal canal; and

a cord structure located within the passageway of the column portion, wherein the cord structure is securable within the passageway such that an annular region is formed between a wall of the passageway and the cord structure.

2. The model apparatus of claim 1, further comprising a fluid occupying the annular region.

3. The model apparatus of claim 1, wherein the passageway varies in cross-sectional area and cross-sectional shape over its longitudinal length.

4. The model apparatus of claim 1, wherein the cord structure varies in cross-sectional area and cross-sectional shape over its longitudinal length.

5. The model apparatus of claim 1, further comprising at least one root element extending between the cord structure and the wall of the passageway.

6. The model apparatus of claim 1, wherein the column portion comprises two mating halves, each half defining a portion of the passageway.

7. The model apparatus of claim 2, further comprising fin members extending between the cord structure and the wall of the passageway, the fin members operable to partition the annular region into two or more longitudinal chambers.

8. The model apparatus of claim 7, wherein the fin members comprise three fin members operable to partition the annular region into three longitudinal chambers.

9. The model apparatus of claim 7, wherein the fin members substantially restrict exchange of the fluid between a first longitudinal chamber and a second longitudinal chamber.

10. The model apparatus of claim 2, wherein the fluid comprises saline.

11. The model apparatus of claim 2, further comprising a pump assembly operatively coupled to the passageway.

12. The model apparatus of claim 11, wherein the pump assembly is operable to create a substantially continuous flow of the fluid through the annular region.

13. The model apparatus of claim 12, wherein the pump assembly comprises a peristaltic pump.

14. The model apparatus of claim 2, further comprising an oscillatory flow apparatus operable to create an oscillating flow of the fluid through the annular region.

15. The model apparatus of claim 2, further comprising a sample taking device located at one or more locations along the passageway.

16. The model apparatus of claim 15, wherein the sample taking device comprises a microdialysis probe.

17. The model apparatus of claim 1, wherein the model body comprises a transparent material.

18. The model apparatus of claim 17, wherein the transparent material comprises acrylic plastic.

19. The model apparatus of claim 1, further comprising a catheter port extending from the passageway through the model body.

20. The model apparatus of claim 1, wherein a cross section of the passageway generally forms an ellipse.

21. The model apparatus of claim 1, further comprising tube elements extending along a portion of the length of the cord structure, each tube element comprising a first end coupled to the cord structure.

22. A method of characterizing a distribution of a substance in a human spinal column, the method comprising:

introducing a second fluid comprising the substance into a first fluid, the first fluid located within an annular region of a spinal model, the spinal model comprising;

a model body comprising a column portion, the column portion defining a curved passageway in the shape of a human spinal canal; and

a cord structure located within the passageway of the column portion, wherein the cord structure is securable within the passageway such that the annular region is formed between a wall of the passageway and the cord structure; and

detecting a concentration of the substance within the first fluid at one or more locations along the passageway.

23. The method of claim 22, further comprising visually monitoring the distribution of the substance within the first fluid through a transparent portion of the column portion.

24. The method of claim 22, wherein detecting the concentration of the substance within the first fluid comprises:

gathering a sample from the annular region with a probe; and

detecting the concentration of the substance within the sample.

25. The method of claim 24, wherein detecting the concentration of the substance comprises detecting the concentration with high performance liquid chromatography.

26. The method of claim 22, further comprising circulating the first fluid within the annular region.

27. The method of claim 26, wherein circulating the first fluid comprises inducing a continuous flow of the first fluid.

28. The method of claim 26, wherein circulating the first fluid comprises inducing an oscillating flow of the first fluid.

29. The method of claim 22, wherein introducing the second fluid comprises infusing the second fluid with a catheter.

30. A three-dimensional in-vitro model of a human spine comprising:

a column portion comprising a substantially enclosed passageway formed therein;

a cord structure securable within the passageway, wherein an annular region is formed between a wall of the passageway and the cord structure; and

one or more connecting elements spanning across the annular region between the cord structure and the wall of the passageway.

31. The model of claim 30, further comprising one or more longitudinal fin members spanning across the annular region between the cord structure and the wall of the passageway.

32. The model of claim 30, further comprising a catheter port extending through the column portion to the passageway.

33. The model of claim 30, further comprising tube elements extending generally along a portion of the cord structure, each tube element comprising a first end coupled to the cord structure.

34. The model of claim 30, wherein the column portion comprises two mating halves, each halve defining a portion of the passageway.

35. A three-dimensional in-vitro model of a human spine comprising:

a column portion comprising a substantially enclosed passageway formed therein;

a plurality of sampling ports extending through the column portion to the passageway;

a cord structure securable within the passageway, wherein an annular region is formed between a wall of the passageway and the cord structure; and

a first fluid substantially filling the annular region.

36. The model of claim 35, further comprising a pump assembly, the pump assembly operable to induce a continuous flow of the first fluid.

37. The model of claim 35, further comprising an oscillatory device operable to induce an oscillatory flow of the first fluid.

38. The model of claim 37, wherein the oscillatory device comprises a hydraulic cylinder.

39. The model of claim 38, wherein the oscillatory device further comprises a pneumatic cylinder.

40. The model of claim 35, further comprising a temperature control unit operable to maintain the model at a predetermined temperature.

41. A method of characterizing a distribution of a drug in a human spinal column, the method comprising:

filling an annular region of a spinal model with a first fluid, the spinal model comprising;

a column portion comprising a substantially enclosed passageway formed therein; and

a cord structure securable within the passageway, wherein the annular region is formed between a wall of the passageway and the cord structure;

introducing a second fluid containing the drug into the first fluid at a predetermined location along the passageway; and

detecting a concentration of the drug contained in the first fluid at one or more locations along the passageway.

42. The method of claim 41, further comprising visually monitoring the distribution of the drug within the first fluid through a transparent portion of the column portion.

43. The method of claim 41, wherein introducing the second fluid comprises infusing the second fluid with a catheter.

44. The method of claim 41, wherein detecting the concentration of the drug contained in the first fluid comprises:

gathering a substance sample from the annular region with a probe; and

detecting the concentration of the drug within the substance sample.

45. The method of claim 41, further comprising circulating the first fluid within the annular region.

46. The method of claim 41, further comprising maintaining the spinal model at a predetermined temperature.