DEVICE AND METHOD

Abstract

A device for modulating biological tissue and/or bone conformation, the device including a shape memory material and being capable of modulating biological tissue and/or bone conformation simultaneously in at least two dimensions, a process for producing the device, a process for modulating biological tissue and/or bone using the device, and uses thereof.

Claims

1. A device for modulating biological tissue and/or bone conformation, the device comprising a shape memory material and being capable of modulating biological tissue and/or bone conformation simultaneously in at least 2 dimensions.

2. The device according to claim 1, wherein the device is capable of modulating at least one of biological tissue and bone conformation simultaneously in 3 dimensions.

3. The device according to claim 1, wherein the shape memory material is arranged into a predetermined 3-dimensional conformation.

4. The device according to claim 3, wherein the shape memory material is a continuous sheet arranged in the predetermined 3-dimensional conformation.

5. The device according to claim 3, wherein the shape memory material is a mesh or web arranged in the predetermined 3-dimensional conformation.

6. The device according to claim 5, wherein the mesh or web comprises a network of geometric shapes.

7. The device according to claim 1, wherein the shape memory material comprises a shape memory alloy and/or a shape memory polymer.

8. The device according to claim 7, wherein the shape memory material comprises a shape memory alloy.

9. The device according to claim 8, wherein the shape memory alloy is an alloy of nickel and titanium.

10. The device according to claim 9, wherein the shape memory alloy is nitinol.

11. The device according to claim 1, for use in the modulation of at least one of biological tissue and bone conformation.

12. The device for use according to claim 11 in calvarial remodeling.

13. A process for producing a device for modulating biological tissue and/or bone conformation, the process comprising: (i) determining the current and desired conformations of the biological tissue and/or bone; (ii) shaping a device comprising a shape memory material into the desired conformation at a temperature around or above body temperature; and (iii) moulding the device into the current biological tissue and/or bone conformation at a temperature below body temperature.

14. The process according to claim 13, wherein the determination of the current conformation of the biological tissue and/or bone is conducted using computed tomography.

15. The process according to claim 13, wherein the determination of the desired conformation of the biological tissue and/or bone is conducted using a principal component analysis-derived, computer-generated template.

16. The process according to claim 13, wherein shaping of the device is conducted at a temperature between the forming temperature of the shape memory material and slightly below the melting point of the shape memory material.

17. The process according to claim 13, wherein the device comprising a shape memory material is a device according to claim 1.

18. A process for modulating biological tissue and/or bone, the process comprising: (i) optionally surgically weakening the tissue and/or bone to be treated, such as by making one or more scores to an area of the tissue and/or bone, and (ii) attaching the device of claim 1 to the tissue and/or bone to be modulated and allowing it to warm to body temperature.

19. The device according to claim 1, further including a plurality of pins and/or screws for attaching the device to a section of biological tissue and/or bone to be modulated.

20. The device for use according to claim 11 in at least one of posterior vault expansion, craniosynostosis and sagittal synostosis.

Description

FIGURES

[0063] FIG. 1

[0064] A schematic adjustment to mandibular shape. A 3D CT scan of the skull is made and from this a stereolithiographic model is made to produce an exact replica of the skull (Figure Ai). In the case shown, the angle of the mandible is too small and so a 3D template is made which will alter the mandible to its desired shape (Figure Aii). A memory material mesh is then taken and moulded to the desired shape of the mandible (Figure B). This is then heated to high temperatures so that the memory of the mesh is fixed in this shape. The framework is then cooled, e.g. to room temperature, so that it is in its malleable phase. The mesh is then moulded to the shape of the existing deformed mandibular angle (Figure C). The mesh is then sterilised and prepared for operative use. At operation, the mandible is prepared by performing multiple corticotomies to weaken the bone (Figure D). The mesh is then fixed to the mandible using multiple pins or screws. The access wound is then closed. As the mesh warms to body temperature, it transforms to its pre-programmed shape. This force distracts and moulds the mandible to the planned shape (Figure E).

[0065] FIG. 2

[0066] A nasal mould comprising top and bottom opposing sections, fixed together by means of screws.

[0067] FIG. 3

[0068] A nitinol sheet obtained from the nasal mould of FIG. 2 following heating and fixation to the pre-programmed, memory conformation, as described in Example 1.

[0069] FIG. 4

[0070] A nitinol mesh for reconstructing a nasal section of tissue and/or bone, as obtained by the procedure of Example 2.

[0071] FIG. 5

[0072] CT scans (top view) of the nitinol mesh of FIG. 4 pre (left image) and post (right image) restoration to the pre-programmed conformation. The image shows dimensions A and B.

[0073] FIG. 6

[0074] CT scans (side view) of the nitinol mesh of FIG. 4 pre (left image) and post (right image) restoration to the pre-programmed conformation. The image shows dimension C.

[0075] FIG. 7

[0076] A nitinol mesh for reconstructing a nasal section of tissue and/or bone, as obtained by the procedure of Example 3.

[0077] FIG. 8

[0078] MIMICS reconstructions (top view) of the nitinol mesh of FIG. 7 pre (dark colouring) and post (light colouring) restoration to the pre-programmed conformation, with the images overlayed. As for FIG. 5, the image shows dimensions A and B.

[0079] FIG. 9

[0080] MIMICS reconstructions (side view) of the nitinol mesh of FIG. 7 pre (dark colouring) and post (light colouring) restoration to the pre-programmed conformation, with images overlayed. As for FIG. 6, the image shows dimension C.

[0081] FIG. 10

[0082] A CT scan of a pig's head into which a nitinol mesh has been implanted and a memory conformation test conducted.

[0083] FIG. 11

[0084] MIMICS reconstructions (top view) of a nitinol mesh prepared by the procedure of Example 2, pre (dark colouring) and post (light colouring) images overlayed, following the memory test of Example 4 in a pig's head model. As for FIG. 5, the image shows dimensions A and B.

[0085] FIG. 12

[0086] MIMICS reconstructions (top view) of a nitinol mesh prepared by the procedure of Example 2, pre (dark colouring) and post (light colouring) images overlayed, following the memory test of Example 4 in a pig's head model. As for FIG. 6, the image shows dimension C.

[0087] FIG. 13

[0088] Illustration showing how deformities of the skull can be corrected using shape memory meshes of the invention, in this case the correction of unicoronal synostosis.

[0089] FIG. 14

[0090] Illustration showing how small intraoral devices according to the invention can be used to create additional alveolar bone to enable the insertion of dental implants.

[0091] FIG. 15

[0092] Illustration showing how a shape memory mesh of the invention can be used to correct congenital or post traumatic deformities of bones of the upper and lower limb.

[0093] FIG. 16

[0094] A3D printed model of a skull having a fusion of the right coronal suture (unicoronal synostosis), which has been modified using modelling clay by a plastic surgeon to reproduce the desired shape of the skull.

[0095] FIG. 17

[0096] A nitinol mesh inside a metal mould for pre-programming of the nitinol mesh into the desired shape of the skull.

EXAMPLES

Example 1

Nitinol Sheet Memory Test

[0097] The nasal area of a healthy female subject (age 37) was scanned using a 3D scanner (Rodin4D apparatus). The scan was processed and the 3D surface of the nose was extracted. The 3D surface was then processed using CADCAM software in order to create the shape of a mould. Both top and bottom sections of a mould were produced to 2 mm thickness. Digital laser metal sintering (DLMS) was used to rapid prototype the top and bottom moulds.

[0098] A hyperelastic nitinol sheet (Ni=55.74%, Ti=44.25%; A.sub.f=31.55° C.) was purchased from Johnson Matthey (Royston, UK). A diamond dental saw was used to create a shape approximating the area of the nose to be treated. The piece of nitinol sheet was inserted into the mould, pressed, and the top and bottom sections of the mould were secured together using screws. The mould was then heated to 500° C. in order to set the nitinol sheet into its pre-programmed, memory shape (austenite phase). The product shape was inspected for suitability.

[0099] The moulded nitinol shape was cooled to −5° C. in order to convert the material into its malleable martensite phase, and flattened. The flattened shape was retained as long as the temperature remained below the transition temperature. Upon gentle heating, in this case using warm water, the nitinol sheet regained its memory shape (austenite phase).

Example 2

Nitinol Mesh Memory Test

[0100] The procedure outlined in Example 1 was repeated for a nitinol mesh, which was produced by creating a number of 2 mm holes in a sheet of nitinol (see FIG. 4). The mesh was also further refined around the border region of the mesh for improved introduction into the mould.

[0101] A CT scan was performed to assess the accuracy of the shape memory test. The results are displayed in Table 1, and show that all dimensions of the mesh were restored to within 2% of the memory shape.

[0102] Pre=before shape memory test—a CT scan was performed immediately after the thermal treatment to set the shape.

[0103] Post=after the shape memory test.

[0104] Scan parameters:

[0105] Slice thickness=0.3 mm;

[0106] Pixel spacing=[0.3 mm, 0.3 mm];

[0107] Row=400; and

[0108] Column=400.

[0109] The images were processed with MIMICS (level set and region growing segmentation of the image) to create the 3D geometry of the nitinol nasal configuration.

TABLE-US-00001 TABLE 1 Dimension Pre (mm) Post (mm) A 99.02 98.56 B 76.58 75.93 C 29.97 30.53

Example 3

Nitinol Mesh Memory Test

[0110] The procedures outlined in Examples 1 and 2 were repeated for a further nitinol mesh, which was produced by creating a number of 2 mm holes in a sheet of nitinol (see FIG. 7). This is with the exception that the mesh and mould were heated to 580° C. in order to set the nitinol sheet into its pre-programmed, memory shape (austenite phase).

[0111] A CT scan was performed to assess the accuracy of the shape memory test. The results are displayed in Table 2, and show that all dimensions of the mesh were restored to within 2% of the memory shape.

[0112] Pre=before shape memory test—a CT scan was performed immediately after the thermal treatment to set the shape.

[0113] Post=after the shape memory test.

[0114] Scan parameters:

[0115] Slice thickness=0.3 mm;

[0116] Pixel spacing=[0.3 mm, 0.3 mm];

[0117] Row=800; and

[0118] Column=400 (800 for pre).

[0119] The images were processed with MIMICS (level set and region growing segmentation of the image) to create the 3D geometry of the nitinol nasal configuration.

TABLE-US-00002 TABLE 2 Dimension Pre (mm) Post (mm) A 95.40 94.33 B 76.06 75.44 C 28.56 28.19

Example 4

Pig Model Memory Test

[0120] The procedure and nitinol mesh as described in Example 2 was assessed in a pig head model.

[0121] A pig head was obtained from a butcher and the flattened nitinol mesh of Example 2 was implanted (see FIG. 10). Due to the temperature of the pig head, the mesh regained its memory shape and was assessed by means of a CT scan (using the same parameters as Example 2). The pre and post images were processed with MIMICS and compared in order to determine the effect imposed by the surrounding tissue of the pig's forehead (see FIGS. 11 and 12). The results showed that, in the case of the C dimension, the mesh returned to within 39% of the memory shape. Thus, the shape of the surrounding tissue was significantly modified by the memory effect of the device when implanted, thereby promoting tissue remodelling and regeneration.

Example 5

Unicoronal Synostosis Distractor

[0122] A nitinol distractor was produced for a patient having developed fusion of the right coronal suture (unicoronal synostosis) by the age of 16 months.

[0123] A CT scan was acquired of the whole skull, and a 3D model was created using MIMICS. A 3D printed model of the skull (from skull top to orbits) was produced by means of a rapid prototyping technique. The model was then modified using modelling clay by a plastic surgeon to reproduce the desired shape of the skull (see FIG. 16). The modified model was scanned using a 3D scanner and the shape of the remodelled skull was superimposed on the initial anatomy.

[0124] The corrected shape of the skull was used to design a metal mould, which was then produced using metal rapid prototyping by direct laser metal sintering. A nitinol mesh was produced from a shape memory nitinol sheet, inserted into the mould and treated at 500° C. for 15 min (see FIG. 17). The nitinol mesh was removed from the mould and flattened, and the shape memory effect was tested using hot water (i.e. at or above body temperature). The sheet substantially returned to the pre-programmed shape.