A tool (100, 500, 600) for delivering therapeutic materials to an intervertebral disc via a sub-ligamentous space, the tool (100, 500, 600) being configured to be positioned at an interface of a longitudinal ligament and an outer surface of the intervertebral disc, the interface being the sub-ligamentous space, the tool (100, 500, 600) comprising: a first needle (104, 504, 604), and a second needle (106, 506, 606) housed within the first needle (104, 504, 604), wherein an insertion end (112, 512, 612) of the first needle (104, 504, 604) comprises a shallow beveled end and is configured for insertion into the sub-ligamentous space; wherein the second needle (106, 506, 606) is configured to be deployed from within the first needle (104, 504, 604) into at least one of an annulus and a nucleus of the intervertebral disc; and wherein the second needle (106, 506, 606) is configured to deliver the therapeutic materials to the at least one of the annulus and the nucleus, wherein the tool (100, 500, 600) further comprises a spring system configured to move the tool (100, 500, 600) from a retracted position to a deployed position, wherein the spring system comprises at least a plate (118, 518, 618) and a switch (108, 508, 608) coupled to one another, the plate (118, 518, 618) being positioned within the tool (100, 500, 600) and coupled to the second needle (106, 506, 606), the switch (108, 508, 608) being configured to move along an outer surface of the tool (100, 500, 600), and wherein the spring plate (118, 518, 618) is configured to deploy and retract the second needle (106, 506, 606) from the first needle (104, 504, 604) based on a direction of movement of the switch (108, 508, 608), wherein the switch (108, 508, 608) forms an indicator, which is positioned 180° from an angle of curvature of the second needle (106, 506, 606) and configured to indicate an insertion angle of the second needle (106, 506, 606) into the intervertebral disc. a first needle (104, 504, 604), and a second needle (106, 506, 606) housed within the first needle (104, 504, 604), wherein an insertion end (112, 512, 612) of the first needle (104, 504, 604) comprises a shallow beveled end and is configured for insertion into the sub-ligamentous space; wherein the second needle (106, 506, 606) is configured to be deployed from within the first needle (104, 504, 604) into at least one of an annulus and a nucleus of the intervertebral disc; and wherein the second needle (106, 506, 606) is configured to deliver the therapeutic materials to the at least one of the annulus and the nucleus, wherein the tool (100, 500, 600) further comprises a spring system configured to move the tool (100, 500, 600) from a retracted position to a deployed position, wherein the spring system comprises at least a plate (118, 518, 618) and a switch (108, 508, 608) coupled to one another, the plate (118, 518, 618) being positioned within the tool (100, 500, 600) and coupled to the second needle (106, 506, 606), the switch (108, 508, 608) being configured to move along an outer surface of the tool (100, 500, 600), and wherein the spring plate (118, 518, 618) is configured to deploy and retract the second needle (106, 506, 606) from the first needle (104, 504, 604) based on a direction of movement of the switch (108, 508, 608), wherein the switch (108, 508, 608) forms an indicator, which is positioned 180° from an angle of curvature of the second needle (106, 506, 606) and configured to indicate an insertion angle of the second needle (106, 506, 606) into the intervertebral disc.