Composite porous interbodies and methods of manufacture
A method of forming a composite titanium body for use in forming spinal implant interbodies includes selecting a metal alloy body, carving out a top portion and a bottom portion from the metal alloy body, and bonding a porous material to the carved-out top and bottom portions. Multiple pieces may be cut from the composite titanium body, each having a front face formed of the metal alloy, top and bottom portions formed of the porous material, and with a medial portion of the metal alloy extending from the front face to the back. Methods and devices for spinal interbodies having locking mechanisms to prevent bone screw back-out are also described.
1 . A method of manufacturing a composite interbody, the method comprising:
selecting a solid titanium body having a top side and a bottom side;
carving out a portion of the top side of the solid titanium body to form a top portion void;
carving out a portion of the bottom side of the solid titanium body to form a bottom portion void;
diffusion bonding porous titanium to the top portion void;
diffusion bonding porous titanium to the bottom portion void, the steps of diffusion bonding porous titanium to the top portion void and bottom portion void forming a composite titanium block; and
cutting out a composite interbody from the composite titanium block.
2 . The method of claim 1 , wherein the resulting composite interbody is a unitary titanium structure.
3 . The method of claim 1 , wherein the carving out the portion of the top side of the solid titanium body results in a pair of upward extending walls running along opposite edges of the solid titanium body.
4 . The method of claim 3 , wherein the carving out the portion of the bottom side of the solid titanium body results in a pair of downward extending walls running along opposite edges of the solid titanium body.
5 . The method of claim 3 , wherein the diffusion bonding porous titanium to the top portion void comprises placing a body of porous titanium in the top portion void, the body of porous titanium having a thickness greater than a depth of the top portion void.
6 . The method of claim 1 , wherein the porous titanium comprises sheets of porous titanium that have been subjected to an etching process to produce a pore pattern in each sheet, the sheets having then been diffusion bonded together to form the porous titanium.
7 . The method of claim 6 , wherein the sheets are arranged relative to each other to achieve a desired porous pattern in the resulting porous titanium.
8 . The method of claim 1 , wherein a first thickness of the composite titanium block that includes the porous titanium is greater than a second thickness of the composite titanium block that does not include the porous titanium.
9 . The method of claim 1 , wherein the composite interbody comprises
a body having an anterior face and an opposing posterior face, a top portion and a bottom portion, with a medial portion extending through the body from the anterior face to the opposing posterior face; and
the anterior face formed of non-porous titanium alloy, the top portion and bottom portion formed of porous titanium, and the medial portion formed of non-porous titanium alloy.
10 . The method of claim 9 , wherein the anterior face comprises at least one bore for receiving a bone screw, and at least one locking mechanism for preventing back-out of the bone screw, wherein the anterior face further comprises an axial channel proximal to the at least one bore.
11 . The method of claim 10 , wherein the locking mechanism comprises a cylinder with an outwardly projecting tab, the cylinder receivable in the axial channel, and the outwardly projecting tab extending at least partially into the at least one bore.
12 . The method of claim 11 , wherein the outwardly projecting tab of the locking mechanism further comprises an angled face to allow the bone screw to deflect the outwardly projecting tab as it is inserted into the at least one bore.
13 . The method of claim 12 , wherein the outwardly project tab is biased to extend into the at least one bore after it is deflected by the bone screw.
14 . The method of claim 10 ,
wherein the anterior face further comprises an axial channel proximal to the at least one bore; and
wherein the locking mechanism comprises a blocker with at least one outwardly projecting arm, the blocker receivable in the axial channel and rotatable therein between a locked configuration and an open configuration.
15 . The method of claim 10 , wherein the at least one bore is at least partially threaded.
16 . The method of claim 15 , wherein threads of the at least one bore are configured to engage with corresponding threads on the bone screw.
17 . The method of claim 16 , wherein the bone screw has a head portion that is at least partially threaded.
18 . The method of claim 10 , wherein the at least one locking mechanism comprises a shaft portion positioned within the locking bore and a first extension at a proximal end of the shaft portion, wherein the shaft portion is configured to rotate within the locking bore so that the first extension may occupy a blocking position where the first extension at least partially occludes the at least one bore and an open position where the first extension is rotated away from the at least one bore.
19 . The method of claim 18 , further comprising a second bore for receiving a second bone screw, the second bore positioned adjacent to the locking bore, and wherein the at least one locking mechanism further comprises a second extension that, when the first extension occupies the blocking position, the second extension at least partially occludes the second bore and, when the first extension occupies the open position, the second extension is rotated away from the second bore.
20 . The method of claim 9 , wherein the anterior face comprises at least one bore for receiving a bone screw, and at least one locking mechanism for preventing back-out of the bone screw, wherein the anterior face further comprises a locking bore adjacent to the at least one bore, the locking bore configured to receive the at least one locking mechanism.