Surgical implant and methods of additive manufacturing
A method of manufacturing a surgical implant includes simultaneously forming a first component and a second component of the surgical implant. Formation of the first and second components includes depositing a first quantity of material to a building platform and fusing the first quantity of material to form a first layer of the first and second components. The method of manufacturing also includes depositing a second quantity of material over the first layer of the first and second components and fusing the second quantity of material to form a second layer of the first and second components. The surgical implant is fully assembled upon the completion of the formation of the first and second components.
1 . A method of manufacturing a housing assembly of a pedicle screw comprising:
alternately depositing and heating successive layers of a first source material to form a first portion of a first part of the pedicle screw;
alternately depositing and heating successive layers of a second source material subsequent to the formation of the first portion to form a second part of the pedicle screw, the second part being retained by the first part; and
alternately depositing and heating successive layers of the first source material subsequent to the formation of the first portion to form a second portion of the first part,
wherein the first part and the second part are fully assembled upon completion of the formation of the first part and the second part.
2 . The method of claim 1 , wherein forming the second part includes forming a support structure such that upon completion of the formation of the first part and the second part, the second part is attached to the first part by the support structure.
3 . The method of claim 2 , further comprising breaking the support structure such that the second part is movable relative to the first part.
4 . The method of claim 1 , wherein forming the second part includes forming an anvil shaped to support a spinal rod.
5 . The method of claim 1 , wherein depositing each of the first and second source materials includes depositing titanium.
6 . The method of claim 1 , wherein forming the first part and the second part includes forming at least some of the first part and at least some of the second part simultaneously.
7 . The method of claim 1 , further comprising alternately depositing and heating successive layers of a third source material to form a bone screw of a pedicle screw, a bone screw adapted for securement within the first part.
8 . The method of claim 1 , wherein forming the first part includes forming a housing.
9 . A method of forming a pedicle screw housing assembly in a single continuous process comprising:
alternately depositing and heating successive layers of a first source material to form a first part of the pedicle screw;
alternately depositing and heating successive layers of a second source material to form a second part of the pedicle screw,
wherein the first part and the second part are formed such that the second part is captured within the first part, and
wherein forming the second part includes forming an anvil sized to fit within an interior cavity of the first part and having a surface with a saddle shape to receive a spinal rod.
10 . The method of claim 9 , wherein the first part and the second part are formed monolithically and are connected to each other through one or more support structures, the one or more support structures having a stress failure value lower than the first part or the second part.
11 . The method of claim 10 , further comprising applying force to the second part relative to the first part to break the one or more support structures such that the second part is moveable within the first part.
12 . The method of claim 9 , further comprising alternately depositing and heating successive layers of a third source material to form a screw, the formed screw being retainable within the first part and being shaped to receive the anvil while retained within the first part.
13 . The method of claim 9 , wherein depositing each of the first and second source materials includes depositing titanium.
14 . A pedicle screw housing assembly formed through an additive manufacturing process comprising:
a first part formed layer-by-layer by depositing and fusing a first plurality of successive layers of a first material; and
a second part disposed within a cavity of the first part, the second part formed layer-by-layer by depositing and fusing a second plurality of successive layers of a second material, an initial layer of the second plurality of successive layers being formed prior to the formation of a final layer of the first plurality of successive layers, and
a third part disposed within the cavity of the first part, the third part formed layer-by-layer by depositing and fusing a third plurality of successive layers of a third material,
wherein the second part is formed monolithically with the first part such that a weakened portion bridges the first part and the second part, the weakened portion being breakable upon application of a torque to one of the first part and the second part relative to the other of the first part and the second part, and
wherein the third part is a cannulated bone fastener with a plurality of fenestrations extending from an outer surface of the cannulated bone fastener to an inner surface of the cannulated bone fastener that defines the cannulation.
15 . The assembly of claim 14 , wherein the second part is shaped to receive a spinal rod disposed within the first part.
16 . The assembly of claim 14 , wherein the weakened portion includes one or more support structures positioned such that the second part bears onto at least one of the one or more support structures.
17 . The assembly of claim 16 , wherein a portion of the assembly traversing the respective first part, one or more support structures and second part comprises successive layers of material formed through a continuous process.
18 . The assembly of claim 14 , wherein the first material of the first part and the second material of the second part are titanium.
19 . The assembly of claim 14 , wherein the first part is a U-shaped housing and the second part is an insert.