Device to fill a bone void whilst minimising pressurisation

Abstract

Disclosed is a device for implantation into a bone void while minimising the potential for an increase in pressure within the bone void.

Claims

1. An implantable device for insertion into a bone void, the implantable device comprising a bone substitute material and having a cylindrical body and one or more longitudinal channels extending the entire length of the device, where said one or more longitudinal channels allows for depressurisation of the bone void during implantation of the device; the one or more longitudinal channels each intersecting a surface of the device and extending to an axial centerline thereof, and being tapered such that the width of the one or more longitudinal channels opening on an outer, circumferential edge of the implantable device is greater than its width at a base thereof; and wherein the devices have a flat surface on an opposing longitudinal side to the one or more longitudinal channels; and wherein the device has convex, domed or semispherical shaped ends.

2. An implantable device according to claim 1, wherein the one or more longitudinal channels allows for the displacement and/or exit of the void contents.

3. An implantable device according to claim 1, wherein the one or more longitudinal channels tapers in width from the exterior circumference towards its central axis.

4. An implantable device according to claim 3, wherein the one or more longitudinal channels has a taper angle of 10 degrees to 145 degrees.

5. An implantable device according to claim 4, wherein the taper angle of one or more longitudinal channels is from 20 degrees to 50 degrees.

6. An implantable device according to claim 1, wherein an opposing surface to one or more longitudinal channels has a flat surface.

7. An implantable device according to claim 1, wherein the device has a capsule shape, having one or more longitudinal channel intersecting the surface of the device and extending the full length of the device and also extending towards the device centreline.

8. An implantable device according to claim 1, wherein the displacement of the void contents minimises an increase in pressure within the void.

9. An implantable device according to claim 1, wherein the bone substitute material comprises a calcium-based bone substitute material.

10. An implantable device according to claim 1, wherein the implantable device is adapted for insertion into a void that is within an intramedullary canal of a patient.

11. An implantable device according to claim 10, wherein the implantable device is adapted for insertion into a void comprising a defect in bone.

12. An arrangement of two or more implantable devices comprising a plurality of the devices lined up end to end, wherein each of the implantable devices comprises a bone substitute material and has a cylindrical body and one or more longitudinal channels extending the entire length of the device, where said one or more longitudinal channels allows for depressurisation of the bone void during implantation of each device; the one or more longitudinal channels each intersecting a surface of each device and extending to an axial centerline thereof, and being tapered such that the width of the one or more longitudinal channels opening on an outer, circumferential edge of each implantable device is greater than its width at a base thereof; and wherein the devices have a flat surface on an opposing longitudinal side to the one or more longitudinal channels; and wherein each device has convex, domed or semispherical shaped ends.

13. An arrangement according to claim 12, wherein the longitudinal channels are axially aligned with each other.

14. An arrangement according to claim 12, wherein the longitudinal channels are not axially aligned with each other.

15. An arrangement according to claim 12, wherein the arrangement is adapted for insertion into an intramedullary canal of a patient.

16. An implantable device according to claim 1, wherein the one or more longitudinal channels extend the full length of the device.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The various features of the invention, which are applicable as appropriate to all aspects, will now be described in more detail with reference to the following drawings, where:

(2) FIG. 1 shows plan, end and isometric views of the implantable device of the invention with a spherocylindrical or capsule shape and a longitudinal channel.

(3) FIG. 2A shows multiple implantable device(s) of the present invention together in series.

(4) FIG. 2B shows multiple implantable device(s) of the present invention together in series, and how the contents of the bone void or IM canal can be displaced and move through the channel.

(5) FIG. 3A shows a multi-cavity flexible mould mat with cavities that when filled with bone substitute material forms the implantable device.

(6) FIG. 3B shows a cross-section image of the multi-cavity flexible mould mat.

(7) FIG. 4 shows a sectional view of the implantable devices as it may appear in a bone void or IM canal.

(8) FIG. 5 shows an example of a guide tube.

(9) FIG. 6 shows an example of a pusher that may be used with the guide tube.

DETAILED DESCRIPTION OF DRAWINGS

(10) FIG. 1 shows an implantable device 10 of the present invention, which is capsule shaped, having domed, convex or semispherical shaped ends 20. A longitudinally aligned channel 30 intersects the surface of the implantable device and extends towards the cylindrical axis 40 of the implantable device.

(11) FIG. 2A shows multiple implantable devices 10 of the present invention together in series, which are generally capsule shaped, having domed, convex or semispherical shaped ends 20, where the ends 20 create a gap at the exterior 120 of the ends 20 of the implantable device 10. There is no need to have the longitudinal channel 30 of any particular implantable device 10 aligned with the longitudinal channel 30 of an adjacent implantable device 10.

(12) FIG. 2B shows multiple implantable devices 10 of the present invention together in series, showing the venting channel 30 for the contents of the bone void or IM canal 50 through the longitudinal channel 30 and domed, convex or semispherical shaped ends 20.

(13) FIG. 3A shows a multi-cavity flexible mould mat 60 which has cavities 70 in rows 80. Each cavity has a shape that corresponds to the shape of the implantable device 10.

(14) FIG. 3B shows a cross-sectional view of the multi-cavity flexible mould mat 60, of a row of cavities 80. The shape of the cavities 80 corresponds to that of the implantable devices 10, with the longitudinal channels 30 visible.

(15) However, while the multi-cavity flexible mould mat 60 constitutes a typical method of manufacturing the implantable devices 10, the implantable devices 10 may be alternatively produced by a method not described herein, by methods which will be readily apparent to the person skilled in the art.

(16) FIG. 4 shows a sectional; representation of an IM canal 70 and cortex 150, containing an implantable device 10 that has been inserted therein. The longitudinal channel 30 has a taper angle 140.

(17) FIG. 5 shows a guide tube 170 for the insertion of the implantable devices in the bone void or IM canal with a funnel at one end 100. The outside diameter of the guide tube 170 is less than the inside diameter of the medullary canal to be treated. The distal end of the guide tube 170 has a flexible retainer 160 which retains the implantable devices 10 within the guide tube 170 until pressure is applied by the pusher 110 to the implantable devices 10 which will cause the retainer to flex allowing the implantable devices 10 to exist the guide tube 170.

(18) FIG. 6 shows a pusher 110, where the diameter of the pusher 110 is less than the internal diameter of the guide tube 170. The pusher 110 has a circular handle 130, to allow the Surgeon to maintain pressure on the implantable devices 10 whilst retracting the guide tube 170. It is to be understood that various modifications may be made to the device disclosed herein without departing from the scope of the invention.

(19) The longitudinal channel cross section may be semi-circular.

(20) The longitudinal channel cross section may be a straight line.

(21) The longitudinal channel may have some other shape.

(22) Bone cement may be used to form the implantable devices.

(23) It is of course to be understood that the present invention is not intended to be restricted to the foregoing examples which are described by way of example only.

REFERENCES

(24) 1. Shamsuddin, Akhtar, MD (2009) Fat Embolism 2. Issack, Paul S. MD, PHD et al., Fat Embolism and Respiratory Distress Associated with Cemented Femoral Arthroplasty, The American Journal of Orthopedics. 3. Shaikh N; Emergency management of fat embolism syndrome. J Emerg Trauma Shock. 209 January; 2(1):29-33. 4. http://jcp.bmj.com/content/s3-4/1/121.full.pdf+html 5. Rebellow M M et al, Venting Alone is Insufficient in Preventing Complications in the Prophylactic Nailing of Femoral Metastases; Orthopaedic Biomechanics Laboratory, Sunnybrook & Women's College Health Sciences Centre, Toronto, Ontario, Canada; 49.sup.th Annual Meeting of Orthopaedic Research Society; Poster #0997. 6. http://www.patient.co.uk/doctor/fat-embolism-syndrome