Biasing device for spinal device

Abstract

A spinal device includes a rod having a first end disposed in a housing, and a second end that extends out of the housing through an aperture and is movable to extend more from the housing or less from the housing. A biasing device mounted on the rod includes a series of connected at least incomplete coils. A first end of the biasing device is arranged to abut the housing, and a second end of the biasing device opposite the first end is fixed to the rod.

Description

Technical Field

[0001] The present invention relates generally to spinal implants and prostheses, and in particular to add-on or integrated biasing devices for spinal devices, such as spinal rods. Background Art

[0002] Scoliosis is a spinal deformity that affects many people. Current surgical treatment involves affixing long fusion rods to the spine via pedicle screws. The rod system is designed to force the deformed spine into a healthier position.

[0003] Unfortunately, this procedure has serious drawbacks; deformities are rarely perfectly corrected, lifelong long-term fusion is not a desirable clinical scenario, and failure is not uncommon.

[0004] Arnin's U.S. Patent No. 10245081 describes an improved ratchet-type spinal device that includes a rod that can be moved out of a housing. The amount of the rod extending out of the housing can be extended or shortened using a ratchet mechanism. The rod can be connected to standard pedicle screws and other spinal rods or spinal structures using appropriate connectors. Summary of the invention

[0005] As described in more detail below, the present invention seeks to provide an improved spinal device or accessory for a spinal device, ie, an add-on or integral biasing device for a spinal device.

[0006] Therefore, according to a non-limiting embodiment of the present invention, a spinal device is provided, which includes a rod having a first end disposed in a housing, and a second end, the second end extending out of the housing through a hole and being movable to extend more from the housing or less from the housing; and a biasing device, the biasing device is mounted on the rod, the biasing device including a series of connected at least partial coils, wherein the first end of the biasing device is arranged to abut against the housing and the second end of the biasing device opposite to the first end is fixed to the rod.

[0007] The at least incomplete coil may comprise a full coil, or alternatively, a series of connected incomplete coils which do not extend completely around the rod but subtend an angle of less than 360°, each pair of adjacent coils of the incomplete coils being connected by a connecting member, and the connecting members being separated from each other by a circumferential gap.

[0008] According to an embodiment of the invention, a first end of the biasing means is arranged to abut against the housing, and a second end of the biasing means opposite to the first end is provided with a fastener to secure the second end to the rod.

[0009] According to an embodiment of the invention, the axial fixing of the second end determines the pre-tensioning force of the biasing device.

[0010] According to an embodiment of the present invention, the rod is connected to a ratchet mechanism for controlling the amount by which the rod extends from the housing.

[0011] According to an embodiment of the invention, a first multiaxial joint attachment member is located at the second end of the rod and a second multiaxial joint attachment member is located at a portion of the housing.

[0012] According to an embodiment of the present invention, a method for adjusting the curvature of the spine includes: installing a biasing device on a rod of a spinal device mounted on a spinal structure, the biasing device including a series of connected incomplete coils, the series of connected incomplete coils not extending completely around the rod but subtending an angle less than 360°, each pair of adjacent coils of the incomplete coils being connected by a connecting member, and the connecting members being separated from each other by a circumferential gap; and using the biasing device to apply a pushing force to the rod and the spinal structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be more fully understood and appreciated from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0014] Figure 1 is a simplified perspective illustration of a spinal device constructed and operative in accordance with an embodiment of the present invention;

[0015] Figure 2 yes Figure 1 A simplified enlarged illustration of a biasing device of a spinal device;

[0016] Figure 3 is another simplified illustration of a biasing device showing a circumferential gap between the ends of an incomplete coil of the biasing device; and

[0017] Figure 4 is a simplified cross-sectional illustration of a spinal apparatus. DETAILED DESCRIPTION

[0018] Reference now Figure 1-Figure 3 ,Should Figure 1-Figure 3 A spinal device 10 is shown, constructed and operative in accordance with a non-limiting embodiment of the present invention.

[0019] The spinal device 10 includes a rod 12 having a first end 14 ( Figure 4), the first end 14 is disposed in the housing 16; and the second end 18, the second end 18 protrudes from the housing 16 through the hole 19 and can be moved to protrude more from the housing 16 or less from the housing 16. The term "rod" includes any element having a circular or non-circular, regular or irregular outer edge, such as but not limited to a rod, a bar, a lug, a wire, a post, etc.

[0020] like Figure 4 As shown, the rod 12 can be coupled to a ratchet mechanism 20 for controlling the amount that the rod 12 extends from the housing 16. The ratchet mechanism 20 can include: ratchet teeth 22 formed along an axial portion of the rod 12; and a pawl 24 arranged to hook onto one of the teeth 22. The pawl 24 can extend from a controller element 26 mounted around a pivot 27 and provided with an eccentric cam 28. Rotation of the eccentric cam 28 moves the pawl 24 to one of three positions: a) ratcheting engagement with the teeth 22 so that the rod 12 can be progressively moved in one direction, b) locking engagement with the teeth 22 so that the rod 12 cannot be moved at all, and c) disengagement from the teeth 22 so that the rod 12 can be freely moved in both directions. Other ratchet mechanisms can be used. Alternatively, no ratchet mechanism is used; for example, the rod 12 can be pushed by an internal spring within the housing 16.

[0021] Two multi-axial joint attachment members 30 (such as but not limited to bearing races or simple holes) may be provided in the device 10, one at the second end 18 of the rod 12 and the other at the other portion 21 of the housing 16. Both multi-axial joint attachment members 30 are used to attach the device 10 to available bone structure of the spine, such as by pedicle screws passing through the members 30. Note that, as shown in U.S. Pat. No. 10,245,081, even after the fasteners are tightened to the members 30, the fasteners will achieve multi-axial rotation while firmly holding the pedicle screws.

[0022] The device 10 includes a biasing device 32 , which may be an add-on accessory that may be added to the device 10 before or after the device 10 is installed in the patient; alternatively, the biasing device 32 may be provided with the device 10 by the manufacturer.

[0023] The biasing device 32 may include a series of connected at least incomplete coils 34 (e.g., spring coils). In one embodiment, the coils 34 are full coils (full 360°). In another embodiment, the coils 34 are incomplete coils that do not extend completely around the rod 12 but subtend an angle less than 360°, and each pair of adjacent incomplete coils is connected by a connecting member 36. Figure 3, the connecting members 36 are separated from each other by a circumferential gap 38. If the biasing device 32 includes an incomplete coil 34, it can be placed directly on any axial portion of the rod 12, as opposed to a full coil (devices with full coils may be provided by the manufacturer) that must be slid over the end of the rod 12 and then axially slid to the desired axial position. This feature allows the biasing device 32 to be added to the device 10 even after the device 10 has been installed in the patient.

[0024] A first end 40 of the biasing device 32 is arranged against the housing 16 and a second end 42 opposite the first end 40 is provided with a fastener 44, such as a set screw, securing the second end 42 to the rod 12. The axial securing of the second end 42 determines the pretension of the biasing device 32.

[0025] After the device 10 is installed in a patient, in a typical treatment plan, the biasing device 32 provides an urging force to the opposite ends of the device 10 to help straighten the patient's spine.

Claims

1. A spinal device comprising: a housing (16); and a rod (12), a first end (14) of the rod (12) being disposed in the housing (16), a second end (18) of the rod (12) extending out of the housing (16) through a hole (19) and being movable toward or away from the housing (16); It is characterized in that A biasing device (32) is configured to be mounted on the rod (12), the biasing device (32) comprising a series of connected incomplete coils (34), wherein a first end (40) of the biasing device (32) is arranged to abut against the housing (16), and a second end (42) of the biasing device (32) opposite to the first end (40) is provided with a fastener (44) for fixing the second end (42) of the biasing device (32) to the rod (12), wherein the incomplete coils (34) are arranged to extend only incompletely around the rod (12), and each pair of adjacent coils of the incomplete coils (34) are connected by a connecting member (36), and the connecting members (36) are separated from each other by a circumferential gap (38).

2. The spinal device of claim 1, wherein: The axial fixation of the second end (42) of the biasing device (32) to the rod (12) determines the pretension of the biasing device (32).

3. The spinal device of claim 1, wherein: The rod (12) is connected to a ratchet mechanism (20) for controlling the extension amount of the rod (12) from the housing (16).

4. The spinal device of claim 1, wherein: A first multi-axial joint attachment member is located at the second end (18) of the rod (12), and a second multi-axial joint attachment member is located at a portion of the housing (16).

5. The spinal device according to any one of claims 1 to 4, wherein: The fastener (44) is a positioning screw.

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