GB2622698A

GB2622698A - Spine brace

Info

Publication number: GB2622698A
Application number: GB2313458.8A
Authority: GB
Inventors: Humphries Parkes John
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-09-05
Filing date: 2023-09-04
Publication date: 2024-03-27
Also published as: GB202212943D0; GB202313458D0

Abstract

First and second rods 14, 16 are arranged parallel to each other to locate substantially colinearly with the spinal column, the rods being formed in sections 24a-d, 26a-d. Collars 28a-c are located around each vertebra 12a-c and have threaded sockets 40a-e mounted thereon to receive threaded ends of the rod sections. Between the threaded sockets, the sections of rod are coupled together with a ball and socket joint 22a-d. The sections of rod have adjusters so that they can be rota

Description

SPINE BRACE

The present invention relates to surgical assemblies for use on the spine and in particular to a dynamic spine brace which supports vertebrae while removing the 5 requirement to attach the assembly to vertebrae using pedicle screws.

The spine supports the human body and allows a person to move and feel things. The spine has a crucial function in supporting and protecting the spinal cord. The spinal cord consists of nerves which connect the human brain to all parts of the body. The spine consists of 33 vertebrae or hollow bones the upper 24 of which can move. The vertebrae connect with ligaments and muscles and make up the spinal column.

The cervical (neck region) part of the spine is more flexible than the other sections of the spine. It is also more prone to injuries as it is less well protected. The vertebrae in the cervical spine are different and have internal openings for arteries 15 which carry blood to the brain.

The lowest area of the spine is known as the lumbar spine. The majority of humans have five vertebrae in the lumber region, however some humans have six. The vertebrae in the lower spine are slightly larger than other vertebrae in the spine. Pain in the lumbar or lower region of the spine is extremely common owed to the lumbar vertebrae being connected to the pelvis which carries most of a human's weight.

inside each vertebra is a cushion like pad known as an intervertebral disc and these absorb the stress and impacts a human body incurs during movements. In short, these discs prevent the individual vertebrae from grinding or rubbing against each other. The discs have a covering of cartilage that provides support with a softer jellylike centre that provides the actual cushioning The discs also help to protect the nerves that run down the spine. These increase the bodies flexibility and allow humans to bend at the waist.

A 'slipped disc' is an inaccurate term wrongly used to describe a disc protrusion. 30 It suggests a disc has moved out of position, but this is not the case. Discs are held firmly in place by ligaments, muscles, and the vertebrae themselves.

Terms like 'herniated', 'extruded', 'bulged' or 'prolapsed' better describe the situation. The problem is not due to the complete disc slipping out of place but rather a smaller area in the outer disc becoming weakened allowing its jelly-like contents to weep or ooze out. When the jelly type substance makes contact with other structures, such as spinal nerves, this results in referred nerve pain which normally radiates into the legs. A most common site for the discs protruding is in the lower back or lumbar region. As humans get older, they are less at risk of disc protrusion as the discs dry out somewhat and become less able to ooze through a weakened area in the outer shell.

In more serious cases lumbar disk replacement is regularly seen as an alternative to spinal fusion where two vertebrae are permanently joined together. Lumbar disk replacement requires major surgery and a lengthy hospital stay.

Laminectomy is a type of spinal surgery to the cervical, thoracic or lumbar regions of the spine and can be used to relieve stress or compression on the spinal cord. Here surgeons remove the offending Lamina. Lamina is part of the bone that forms a vertebral arch in the spine. Surgeons often remove further offending bone spurs during such surgery.

During surgical procedures for spinal fusion the surgeon fuse together diseased vertebrae preventing movement at particular vertebral segments. Special screws called Pedicle screws are used in spinal fusion surgery to provide a means of securing bracing elements or small plates of titanium against vertebral segments in order to limit their movement. This procedure gives stability and support while the bone is fusing together. The chosen metal for these mechanisms, including the pedicle screws for attaching same is titanium. Pedicle screws have been known to break or slacken off US 9,717,535 discloses an articulation fixation assembly to provide a spine brace. The assembly is an improvement on the earlier assembly shown in Figure 1.

Fixation assembly 100 includes a pair of spinal rods 110. Each rod 110 is inserted into a series of screw assemblies 120 configured for anchoring into a vertebral body. Each screw assembly 120 includes a bone screw 130, a rod receiver 140, and a securing element 150 for locking one of the rods 110 into the rod receiver. Each rod 11 0 includes a first section 110a configured to extend over the cervical vertebrae and a second section 110b configured to attach to the patient's occipital region. The second sections 110b are anchored to an occipital plate 160 having two receivers 170 and two securing elements 180. Each rod 110 is bent to form an angle between its first section 110a and second section 110b.

In conventional occipitocervical fixation assemblies, the rod may be bent prior to placement to form the angle between the first and second sections. The pre-bent rod may be used to connect the screw or hook placed at C2 with the occipital plate. Alternatively, the screw or hook may be placed at CI or C3. Because every patient has a different anatomy, one rod configuration will not suit all patients. Among other variables, the angle between the first and second rod sections will vary from patient to patient. Therefore, a pre-bent rod may not precisely match a patient's anatomy as the rod is placed. In many cases, the pre-bent rod requires further adjustment during placement, and must be bent intraoperatively which is cumbersome and decreases fatigue strength of the rod material posing a significant risk to the patient. US 9,717,535 improves on this by locating a ball and socket joint between the rod sections, now shown in Figure 2 as 210a and 210b. Angular adjustment is done by moving this articulating joint 270 Movement between the sections 210a, 210b may be considered as polyaxial as each section 210a,210b can pivot in multiple planes with respect to other section 210b,210a via the joint 270. During surgery, the sections 210a,210b can be moved to the correct positions without bending the rods. The ball and socket joint is then screwed together to fix the positions of the sections 210a,210b.

While the fixation assembly 200 aids attachment of a spinal brace to an individual, the bone screws 30, typically pedicle screws, are still required to be screwed into the vertebrae. Such screws are known to have the disadvantages of being very invasive and difficult to insert, and potentially slackening off and breaking. This is exacerbated by the rods fixed position relative to the vertebrae in use which does not account for any spinal curvature in the individual or movement in the spinal column when the individual moves, so placing additional strain on the screws.

It is an object of the present invention to provide a surgical assembly to support a plurality of vertebrae in a spinal column which mitigates at least some of the disadvantages of the prior art.

According to a first aspect of the present invention there is provided a surgical assembly to support a plurality of vertebrae in a spinal column, the assembly comprising: first and second rods arranged parallel to each other to locate substantially colinearly with the spinal column; attachment means to affix the first and second rods to individual vertebra; characterised in that: the first and second rods are each formed in sections with the sections coupled together with a ball and socket joint at the same positions along each rod so that at least two vertebrae are able to move polyaxially with respect to each other in use.

In this way, the vertebrae are supported while allowing the supporting mechanism lateral, forward and rear movement in keeping with the patients body movements. This provides a more comfortable spine brace for an individual while also reducing the strain placed on the attachment means.

Preferably the attachment means is a collar configured to fit around a majority of a vertebra at the midpoint thereof In this way, the attachment means may be considered as a curved member or part-circlip. Preferably, the collar surrounds 55% to 75% of the vertebra. Alternatively, the collar surrounds 60% to 70% of the vertebra. It requires to hold the vertebra without interfering with the pedicle portion or spinal canal. As a vertebra has a natural indent around the midpoint, the member may be sized to locate within the indent so that it remains in position. Preferably each collar has an inner face machined to identically match an outer surface of an individual vertebra. The inner face may be roughened to increase frictional contact to the vertebra. Upper and/or lower edges of the collar may include protrusions to assist in engagement with the vertebra surface and prevent vertical movement of the collar. The protrusions may only be on the top and bottom edges of the collars at ends of the assembly, respectively, to prevent the assembly slipping in position.

In this way, the attachment means does not require the use of bone screws such 25 as pedicle screws and is thus both easier to fit and less invasive. It also makes the assembly suitable for individuals whose bone material is failing or in poor condition where the use of screws would not be viable.

Preferably, each collar has two threaded sockets arranged opposite each other to engage with an end of sections of the first and second rods respectively. The threaded sockets may be double headed so that ends of sections of rods can be located above and below the collar. This arrangement allows for attachment to more than two vertebra.

Preferably, an end of the section of the rod is also threaded so that it engages in the threaded socket. An opposing end of the section of the rod with have either 35 the ball or socket of the ball and socket joint. In this way, a ball and socket joint is located between adjacent collars. The sections of rods on either side of the ball and socket joint will preferably have left and right hand threads respectively.

When the collars are located on the vertebrae, adjustment of the sections of rods by the degree of engagement at the screw threads will vary the distance between the collars and consequently the distance between the vertebrae. This can be used to take the weight of a burst or failed disc located between the vertebrae and allow a surgeon to remove the discs "leaked/bulged" internal jelly and so eliminate any pain.

The degree of articulation provided by the ball and socket joint will allow the to lateral, forward and rear movement in keeping with the bodies movement while their 'automatic' operation will take the majority of weight off the failed or failing discs within the vertebrae.

Preferably, adjustment means are provided on the sections of the rods to allow them to be screwed in and out of the threaded sockets and so adjust the respective 15 distance between a collar and the ball and socket joint.

Preferably, the adjustment means is via machined holes through each rod about the rods centre into which a 'Tommy bar' can be inserted to rotate them. In this way, as adjustment using a Tommy bar is familiar to surgeons, this is an established mechanism.

Alternatively, the adjustment means may be by having a square section machined about the centre of the rods which would facilitate their tightening and/or loosening with a small spanner. Optionally, the adjustment means may be by having a centre of the rods including a knurled surface in order to allow the surgeon to tighten the rods with their fingers.

It will be noted that although the terms vertical, upper and lower are used these are merely for descriptive purposes and are relative as the individual patient may be in a horizontal position.

An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying figures of which: Figure 1 is a surgical assembly to support a plurality of vertebrae in a spinal column according to the prior art; Figure 2 is a joint arrangement for use in the surgical assembly of Figure 1, also according to the prior art; and Figures 3(a)-(d) are views of a surgical assembly to support a plurality of vertebrae in a spinal column according to an embodiment of the present invention.

Referring to Figures 3(a)-(d) there is illustrated a surgical assembly to support a plurality of vertebrae in a spinal column, generally indicated by reference 5 numeral 10, arranged upon three vertebrae 12a-c according to an embodiment of the present invention.

The assembly 10 has first and second rods 14,16 arranged parallel to each other to locate substantially colinearly with the spinal column 18 and attachment means, generally referenced as 20, to affix the first and second rods 14,16 to individual vertebra 12a-c. The first and second rods 14,16 are each formed in sections 24ad,26a-d with the sections coupled together with a ball and socket joint 22a-d at the same positions along each rod 14,16.

The attachment means 20 is a via a collar 28a-c located around each individual vertebra 12a-c. These may be considered as half collars or circlips. The collars 28a-c are bands of material, most preferably in metal such as titanium or stainless steel, which extend around the body 30 of the vertebrae only sufficiently enough to remain attached but without impinging on the pedicle 32 or spinal canal 34. Thus, they cover over 50% of the circumference but are preferably covering 60% to 70%. The width of the collar 28a-c is determined by the width of the natural indent/groove or valley on the vertebrae around its midpoint, so that the collar 28a-c will sit within the indent. An inner surface 36 of each collar 28 is machined to identically match the outer surface 38 of an individual vertebra 12. The outer surface 38 profile will have been obtained via scans made on the patient.

The inner faces 36 of the upper collar 28a will have small vertical protrusions (not visible on the drawings) allowing this collar 28a to engage with the vertebrae 12a thus preventing the collar 28a from sliding up the vertebrae once the mechanism 20 is secured around the same. The lower collar 28c of the mechanism 20 will also have protrusions however these will be downward pointing to ensure that that collar 28c does not vertically slip up the vertebrae I 2c once the assembly 10 is emplaced and functional. All the protrusions will have rough faces to inhibit friction and prevent slippage across the supported vertebrae. If slippage takes place the assembly would not be effective.

At the end of the collars are arranged threaded sockets 40a-e. The threaded sockets 40a-d on the outermost collars 28a,c are single ended while the threaded 35 sockets 40e,f on the central collar 28b is double ended. Each threaded socket 40a-e receives a threaded end of a section of rod 24a-d,26a-d. Each section of rod 24ad,26a-d is threaded at a first end and has either a ball or socket fitting on the opposite end. Where a section of rod 24a-d,26a-d has a ball at an end the handedness (right of left) of the screw thread at its end will be opposite to that of the sections with a socket at its end. Each rod 14,16 is formed with a first single ended threaded socket 40a,b; a section of rod 24a,26a screwed into the threaded socket and having a ball end; a section of rod 24b,26b having a socket end, the socket holding the ball to form a ball and socket joint 22a,c and the section of rod 24a,26a screwed into one side of the double headed threaded socket 40e,f; a further section of rod 24c,26c screwed into the other side of the double headed threaded socket 40e,f and having a ball end; a section of rod 24d,26d having a socket end, the socket holding the ball to form a ball and socket joint 22b,d and the section of rod 24d,26d screwed into a threaded socket 40c,d.

Each section of rod 24a-d,26a-d includes an adjuster 42.1n the figures the adjuster is a squared section of the rod 14,16 on which a user can locate a spanner and rotate the section of rod 24a-d,26a-d. Alternatively the adjuster could be provided by a hole drilled perpendicularly through the section of rod. A 'Tommy Bar' can then be inserted through the hole to rotate the section of rod 24a-d,26a-d. Yet still the section of rod 24a-d,26a-d could have a knurled surface to allow a user to grip the rod and turn it to rotate the section of rod 24a-d,26a-d. Rotation of each section of rod 24a-d,26a-d causes the length of the section of rod 24a-d,26a-d to be adjusted as it enters or exits the threaded socket. Such adjustment allows the user to set the distance between neighbouring threaded sockets and the vertebrae 12a-c. The adjuster selected will be selected to be the most efficient means while ensuring they cannot transfer dangerous pressure onto vertebrae.

The ball and socket joints 20 provide articulation by giving polyaxial movement and when arranged in the rods 14,16 allow for lateral, forward and rear movement of the vertebrae 12a-c relative to each other. This allows the patient to move their spine as normal.

A surgeon will implant the assembly 10 by locating the collars 28a-c around the selected vertebrae 12a-c and then by adjusting the lengths of the sections of rods 24a-d,26a-d, the vertebrae 12a-c are moved apart so that access to the intervertebral discs between the vertebrae is obtained This separation eases the weight on the disc and consequently limits the oozing of the jelly like substance of the disc or allows for its removal. As the substance can no longer reach the spinal nerves, the pain experienced by the patient is alleviated. With the disc removed, cushioning is lost so that the assembly 10 holds the vertebrae 12a-c apart to prevent grinding or rubbing against each other.

In an embodiment, the assembly can be manufactured in two or possibly thee sections with each section being assembled around the targeted vertebrae once 5 the surgeons have gained access to the chosen vertebrae.

Once emplaced each of the two or three sections will be permanently interconnected or linked together with small rods which are manufactured with left and right hand threads at their ends. The opposing threads will allow the interconnected sections to be tightened around the targeted vertebrae. These joining rods will have pre-formed holes through their centres allowing the surgeon to rotate the rod with a small tool known as a "Tommy Bar. The pressure applied to the joining rods by the Tommy Bar must not be excessive for fear of damaging the vertebrae by crushing.

Once in position each section of the assembly will be permanently linked together with slightly heavier rods to secure the sections in their designed location namely vertically. These heavier rods will also be engineered with left and right hand thread at their ends. Each end of the heavier vertical rods will incorporate ball & socket fittings allowing the supporting mechanism lateral, forward and rear movement in keeping with the bodies movements.

These ball and socket joints are the key to the functioning of the supporting apparatus as their 'automatic' operation will take the majority of the weight off the failed or failing discs within the vertebrae.

An advantage of the proposed assembly is that it does not impinge upon any spinal nerves. The inventor understands that 'herniated', 'extruded', 'bulged' or 'prolapsed' lumbar discs put pressure upon or pinch spinal nerves leading to chronic back pain and worsening leg problems. It is believed that the assembly of the present invention can alleviate these symptoms.

The assembly will be manufactured in metal such as titanium or stainless steel. While plastic and ceramic materials could be used tests would be needed to establish the weight which such mechanism can safety support. However, normal vertebral elements hold up the spine with the spinal column supporting circa half of bodies weight with the other half of the bodies weight being supported by muscles.

The assembly is preferably for supporting the lumbar vertebrae within the human backbone. These vertebrae are known as the Li, L2, L3, L4, & L5 vertebrae and support higher regions of the backbone. Human ribs are not joined to the lumbar vertebrae so it is easier to affix the annular collars around two or more of the lumbar vertebrae. However, the present invention can be engineered for surrounding smaller sections of the upper vertebrae and those with attached ribs.

The present invention therefore provides a support the lumber vertebrae to alleviate the low back pain and associated problems experienced by patients. Advantageously, unlike other mechanisms attached to the vertebrae to engineer fusing of vertebrae the present invention does not require to be fixed to the vertebrae with pedicle screws. This provides a surgical assembly which can be used on patients whose bone material in the vertebrae is failing or in a poor condition for whom pedicle screws cannot be used.

While the drawings illustrate the assembly for three vertebrae, the assembly 10 15 can be used on any number of vertebrae greater than two.

Claims

CLAIMS 1. 2. 3. 4. 5. 6. 7. 8.A surgical assembly to support a plurality of vertebrae in a spinal column, the assembly comprising: first and second rods arranged parallel to each other to locate substantially colinearly with the spinal column; attachment means to affix the first and second rods to individual vertebra; characterised in that: the first and second rods are each formed in sections with the sections coupled together with a ball and socket joint at the same positions along each rod so that at least two vertebrae are able to move with respect to each other in use.
A surgical assembly according to claim 1 wherein the attachment means is a collar configured to fit around a majority of a vertebra at the midpoint thereof, there being a plurality of collars to fit individual vertebra.
A surgical assembly according to claim 2 wherein the collar surrounds 55% to 75% of the vertebra.
A surgical assembly according to claim 3 wherein the collar surrounds 60% to 70% of the vertebra.
A surgical assembly according to any one of claims 2 to 4 wherein the collar has an inner face machined to identically match an outer surface of an individual vertebra.
A surgical assembly according to claim 5 wherein the inner face is roughened to increase frictional contact to the vertebra.
A surgical assembly according to any one of claims 2 to 6 wherein upper and/or lower edges of the collar may include protrusions to assist in engagement with the vertebra surface and prevent vertical movement of the collar.
A surgical assembly according to any one of claims 2 to 7 wherein each collar has two threaded sockets arranged opposite each other to engage with an end of sections of the first and second rods respectively.
9. A surgical assembly according to claim 8 wherein the threaded sockets are double headed so that ends of sections of rods can be located above and below the collar.
10. A surgical assembly according to claim 8 or claim 9 wherein an end of the section of the rod is also threaded so that it engages in the threaded socket.
11. A surgical assembly according to claim 10 wherein an opposing end of the section of the rod with have either the ball or socket of the ball and socket joint.
12. A surgical assembly according to claim 11 wherein the sections of rods on either side of the ball and socket joint have left and right hand threads respectively.
13. A surgical assembly according to claim 11 or claim 12 wherein adjustment means are provided on the sections of the rods to allow them to be screwed in and out of the threaded sockets and so adjust the respective distance between a collar and the ball and socket joint.
14. A surgical assembly according to claim 13 wherein the adjustment means is via machined holes through each rod about the rods centre into which a 'Tommy bar' can be inserted to rotate them.
15. A surgical assembly according to claim 13 wherein the adjustment means is by having a square section machined about the centre of the rods which facilitates their tightening and/or loosening with a spanner.
16. A surgical assembly according to claim 13 wherein the adjustment means is by having a centre of the rods including a knurled surface in order to allow a surgeon to tighten the rods with their fingers.