Temporarily flexible implantable rod placement and fabrication
Disclosed are various embodiments for forming spinal rod members for use in pedicle screw systems for spinal fixation surgery and systems. A system can include a pedicle screw having a pedicle screw head and a pedicle screw shaft, the pedicle screw head comprising an aperture for receiving and retaining a spinal rod member relative to the pedicle screw. The spinal rod member can include an elongated tubular membrane having a flexible body and a spinal rod body formed of a compound, where the spinal rod body is formed by insertion of a liquid compound into the elongated tubular membrane and a hardening of the liquid compound or other similar process for conversion of the flexible rod to a rigid rod. The pedicle screw head can include a channel configured to receive and retain the spinal rod member.
1 . A system, comprising:
a pedicle screw comprising:
a pedicle screw head;
a pedicle screw shaft for implanting the pedicle screw in vertebra of a mammalian body; and
a pedicle screw aperture;
a coupling element attachable to the pedicle screw head; and
a spinal rod member retained in the pedicle screw aperture and secured by the coupling element, wherein the spinal rod member comprises:
an elongated tubular membrane having a flexible body and a hollow interior; and
a spinal rod body formed inside the flexible body by insertion of a compound into the flexible body that is converted into a solid body within the hollow interior through hardening of the compound, the elongated tubular membrane being formed of a material that provides structural resistance when the coupling element is attached to the pedicle screw head such that the spinal rod body is of a substantially uniform cross-section, and the elongated tubular membrane being removable from the spinal rod body after hardening of the compound.
2 . The system of claim 1 , wherein the hardening of the compound is performed by applying at least one of: a change in temperature of the compound, an application of light to the compound, an application of electricity to the compound, and an application of a hardening agent to the compound.
3 . The system of claim 1 , wherein the compound comprises polymethylmethacrylate (PMMA).
4 . The system of claim 1 , wherein a cross-section of the elongated tubular membrane is substantially similar to a cross-section of the pedicle screw aperture that receives and retains the spinal rod member.
5 . The system of claim 1 , wherein the spinal rod member has a substantially straight shape or a curvilinear shape.
6 . The system of claim 1 , wherein the coupling element is detachable from the pedicle screw head.
7 . The system of claim 1 , wherein the pedicle screw shaft comprises threaded elements for insertion into the vertebra.
8 . A method, comprising:
providing a pedicle screw, wherein the pedicle screw comprises:
a pedicle screw head;
a pedicle screw shaft for implanting the pedicle screw in vertebra of a mammalian body;
a pedicle screw aperture; and
a coupling element attachable to the pedicle screw head;
providing a spinal rod member that is retained in the pedicle screw aperture and secured by the coupling element, wherein the spinal rod member comprises:
an elongated tubular membrane having a flexible body and a hollow interior; and
a spinal rod body detachable from the elongated tubular membrane and formed inside the flexible body within the hollow interior by an insertion of a compound into the flexible body that is converted into a solid body within the hollow interior through hardening of the compound, the elongated tubular membrane being formed of a material that provides structural resistance when the coupling element is attached to the pedicle screw head such that the spinal rod body is of a substantially uniform cross-section, and the elongated tubular membrane being removable from the spinal rod body after hardening of the compound.
9 . The method of claim 8 , wherein the compound comprises polymethylmethacrylate (PMMA).
10 . The method of claim 8 , wherein a cross-section of the elongated tubular membrane is substantially similar to a cross-section of the screw head aperture that receives and retains the spinal rod member.
11 . The method of claim 8 , wherein the spinal rod member has a substantially straight shape or a curvilinear shape.
12 . The method of claim 8 , further comprising:
attaching the pedicle screw to a first vertebrae of a spine, the pedicle screw being a first pedicle screw;
attaching a second pedicle screw to a second vertebrae of the spine, the first pedicle screw and the second pedicle screw each comprising a second pedicle screw head and a second pedicle screw shaft, the second pedicle screw comprising a second aperture configured to retain a spinal rod member relative to the first pedicle screw and the second pedicle screw; and
forming the spinal rod member by:
positioning a flexible and elongated tubular membrane into the pedicle screw head of the first pedicle screw and the second pedicle screw;
attaching the coupling element to the pedicle screw head;
inserting a liquid compound into the elongated tubular membrane; and
performing the hardening of the liquid compound to form a hardened spinal rod member body.
13 . The method of claim 12 , wherein the hardening of the liquid compound is performed by applying at least one of: a change in temperature of the compound, an application of light to the compound, an application of electricity to the compound, and an application of a hardening agent to the compound.
14 . The method of claim 8 , wherein the coupling element is detachable from the pedicle screw head.
15 . A method, comprising:
attaching a first pedicle screw to a first vertebrae of a spine;
attaching a second pedicle screw to a second vertebrae of the spine, the first pedicle screw and the second pedicle screw each comprising a pedicle screw head, a coupling element attachable to the pedicle screw head, and a pedicle screw shaft, the coupling element being configured to secure the spinal rod member to the pedicle screw head; and
forming a spinal rod member that is retained by the pedicle screw head by:
positioning a flexible and elongated tubular membrane into the pedicle screw head of the first pedicle screw and the second pedicle screw and attaching the coupling element to the pedicle screw head, the flexible and elongated tubular membrane having a hollow interior;
inserting a compound into the flexible and elongated tubular membrane within the hollow interior; and
hardening the compound to form a hardened and rigid spinal rod member body, wherein the hardening of the compound is performed by applying at least one of: a change in temperature of the compound, an application of light to the compound, an application of electricity to the compound, and an application of a hardening agent to the compound, the elongated tubular membrane being formed of a material that provides structural resistance when the coupling element is attached to the pedicle screw head such that the spinal rod body is of a substantially uniform cross-section, and the elongated tubular membrane being removable from the spinal rod body after hardening of the compound.
16 . The method of claim 15 , wherein the compound comprises Polymethylmethacrylate (PMMA).
17 . The method of claim 15 , wherein the cross-section of the elongated tubular membrane is substantially similar to a cross-section of a channel of the pedicle screw head of the first pedicle screw and the second pedicle screw configured to receive and retain the spinal rod member.
18 . The method of claim 15 , wherein the coupling element is detachable from the pedicle screw head.
19 . The method of claim 15 , wherein the spinal rod member has a substantially straight shape or a curvilinear shape.