Maintenance feature in magnetic implant
A distraction system includes a distraction rod having one end configured for affixation to at a first location on patient. The system further includes an adjustable portion configured for placement in the patient at a second location, the adjustable portion comprising a housing containing a magnetic assembly comprising a magnet, the magnetic assembly secured to a threaded element that interfaces with an opposing end of the distraction rod. The system includes a magnetically permeable member in proximity to the magnetic assembly and covering an arc of less than 360° of the adjustable portion.
1. A magnetic assembly comprising:
a rotatable magnet configured to be disposed in an adjustable implant and configured to change a dimension of the adjustable implant upon a rotation of the rotatable magnet; and
a maintenance member disposed in the magnetic assembly in proximity to the magnet, wherein the maintenance member is configured to attract at least one pole of the rotatable magnet when at least one pole of the rotatable magnet is in proximity to the maintenance member;
wherein the maintenance member covers an arc of less than 360 degrees of the circumference of the rotatable magnet.
2. The magnetic assembly of claim 1 , wherein the maintenance member covers an arc of less than 180 degrees of the circumference of the rotatable magnet.
3. The magnetic assembly of claim 1 , wherein the maintenance member covers an arc of less than 120 degrees of the circumference of the rotatable magnet.
4. The magnetic assembly of claim 1 , wherein the magnetic assembly is configured to adjust the adjustable implant in a specific graduation for each half rotation of the rotatable magnet relative to the maintenance member.
5. The magnetic assembly of claim 4 , the specific graduation comprising 0.16 mm per rotation of the rotatable magnet.
6. The magnetic assembly of claim 4 , the specific graduation comprising 0.10 mm per rotation of the rotatable magnet.
7. The magnetic assembly of claim 4 , the specific graduation comprising 0.20 mm per rotation of the rotatable magnet.
8. A magnetic assembly for an adjustable implant, the magnetic assembly comprising:
a rotatable magnet configured to be disposed in the adjustable implant and configured to change a dimension of the adjustable implant upon a rotation of the rotatable magnet; and
a maintenance member disposed in the magnetic assembly in proximity to the rotatable magnet, wherein the maintenance member is configured to attract at least one pole of the rotatable magnet when at least one pole of the rotatable magnet is in proximity to the maintenance member;
wherein upon application of a moving magnetic field, the rotatable magnet is configured to rotate and change the dimension of the adjustable implant; and
wherein the maintenance member covers an arc of less than 180 degrees of the circumference of the rotatable magnet.
9. The magnetic assembly of claim 8 , wherein the maintenance member covers an arc of less than 120 degrees of the circumference of the rotatable magnet.
10. The magnetic assembly of claim 8 , wherein the magnetic assembly is configured to adjust the adjustable implant in a specific graduation for each half rotation of the rotatable magnet relative to the maintenance member.
11. The adjustable implant comprising the magnetic assembly of claim 8 .