An implant system for positioning a flexible spacer (10; 60; 70; 80) between adjacent vertebrae, the flexible implant system comprising: a flexible interbody spacer (10; 60; 70; 80) for positioning between adjacent vertebrae, the flexible spacer (10; 60; 70; 80) comprising: a top surface and an opposed bottom surface, each configured to engage an adjacent vertebra, and opposing side surfaces extending between the top surface and the bottom surface; a front end and an opposed back end extending between the top and bottom surfaces (16, 17), a central axis extending between the front end and the back end, and a lateral axis defined between the opposing side surfaces and perpendicular to the central axis, the spacer (10; 60; 70; 80) defining a length from the front end to the back end along the central axis; and at least one hinge section spaced along the length of the spacer (10; 60; 70; 80), wherein the at least one hinge section allows the spacer (10; 60; 70; 80) to flex about the lateral axis, the system further comprising: a guide rail including a guide rail body that defines a proximal end, an opposed distal end, and a track extending between the proximal end and the distal end along a non-linear path, the flexible interbody spacer (10; 60; 70; 80) slidably engagable with the track to guide the flexible interbody spacer (10; 60; 70; 80) from the proximal end to the distal end along the non-linear path. a flexible interbody spacer (10; 60; 70; 80) for positioning between adjacent vertebrae, the flexible spacer (10; 60; 70; 80) comprising: a top surface and an opposed bottom surface, each configured to engage an adjacent vertebra, and opposing side surfaces extending between the top surface and the bottom surface; a front end and an opposed back end extending between the top and bottom surfaces (16, 17), a central axis extending between the front end and the back end, and a lateral axis defined between the opposing side surfaces and perpendicular to the central axis, the spacer (10; 60; 70; 80) defining a length from the front end to the back end along the central axis; and at least one hinge section spaced along the length of the spacer (10; 60; 70; 80), wherein the at least one hinge section allows the spacer (10; 60; 70; 80) to flex about the lateral axis, the system further comprising: a guide rail including a guide rail body that defines a proximal end, an opposed distal end, and a track extending between the proximal end and the distal end along a non-linear path, the flexible interbody spacer (10; 60; 70; 80) slidably engagable with the track to guide the flexible interbody spacer (10; 60; 70; 80) from the proximal end to the distal end along the non-linear path. a top surface and an opposed bottom surface, each configured to engage an adjacent vertebra, and opposing side surfaces extending between the top surface and the bottom surface; a front end and an opposed back end extending between the top and bottom surfaces (16, 17), a central axis extending between the front end and the back end, and a lateral axis defined between the opposing side surfaces and perpendicular to the central axis, the spacer (10; 60; 70; 80) defining a length from the front end to the back end along the central axis; and at least one hinge section spaced along the length of the spacer (10; 60; 70; 80), wherein the at least one hinge section allows the spacer (10; 60; 70; 80) to flex about the lateral axis, the system further comprising: a guide rail including a guide rail body that defines a proximal end, an opposed distal end, and a track extending between the proximal end and the distal end along a non-linear path, the flexible interbody spacer (10; 60; 70; 80) slidably engagable with the track to guide the flexible interbody spacer (10; 60; 70; 80) from the proximal end to the distal end along the non-linear path. a guide rail including a guide rail body that defines a proximal end, an opposed distal end, and a track extending between the proximal end and the distal end along a non-linear path, the flexible interbody spacer (10; 60; 70; 80) slidably engagable with the track to guide the flexible interbody spacer (10; 60; 70; 80) from the proximal end to the distal end along the non-linear path.