U.S. patent application number 11/981249 was filed with the patent office on 2008-03-20 for artificial spinal disc replacement system and method.
Invention is credited to Chad Anthony Barrie, Donna Jean Carver, John David Herrera.
Application Number | 20080071375 11/981249 |
Document ID | / |
Family ID | 37943476 |
Filed Date | 2008-03-20 |
United States Patent
Application |
20080071375 |
Kind Code |
A1 |
Carver; Donna Jean ; et
al. |
March 20, 2008 |
Artificial spinal disc replacement system and method
Abstract
An artificial spinal disc implant system for intervertebral disc
replacement (0810) is disclosed which is formed from an upper
(0801) and lower (0802) bracket which mate to upper and lower
spinal vertebrae via upper (0831) and lower (0832) vertebral
contact surfaces on the upper (0801) and lower (0802) brackets. The
upper (0801) and lower (0802) brackets are joined together via
springs (0811) connected to the upper bracket (0801) which rest in
spring guide tracks (0812) on the lower bracket. The springs (0811)
are connected to the upper bracket (0801) via the use of spring
fasteners (0821, 0822). The upper (0801) and lower (0802) brackets
may be installed in sections (0851, 0861, 0871, 0852, 0862, 0872)
using laparoscopic surgical techniques and are attached to
upper/lower spinal vertebrae respectively via adhesive means
applied using injection holes/ports (0841, 0842) in the upper
(0801) and lower (0802) brackets respectively.
Inventors: |
Carver; Donna Jean;
(Mansfield, TX) ; Barrie; Chad Anthony;
(Mansfield, TX) ; Herrera; John David; (Mansfield,
TX) |
Correspondence
Address: |
KEVIN MARK KLUGHART
2516 LILLIAN MILLER PARKWAY
SUITE 115
DENTON
TX
76210-7205
US
|
Family ID: |
37943476 |
Appl. No.: |
11/981249 |
Filed: |
October 31, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11544136 |
Oct 9, 2006 |
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11981249 |
Oct 31, 2007 |
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60725460 |
Oct 10, 2005 |
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Current U.S.
Class: |
623/17.13 ;
623/17.11 |
Current CPC
Class: |
A61F 2310/00029
20130101; A61F 2002/30604 20130101; A61F 2002/4631 20130101; A61F
2/442 20130101; A61F 2002/30574 20130101; A61F 2220/0041 20130101;
A61F 2310/00023 20130101; A61F 2002/30772 20130101; A61F 2230/0034
20130101; A61F 2002/30571 20130101; A61F 2002/30433 20130101; A61F
2002/30187 20130101 |
Class at
Publication: |
623/017.13 ;
623/017.11 |
International
Class: |
A61F 2/44 20060101
A61F002/44 |
Claims
1. An artificial spinal disc replacement system comprising: (a)
One-piece upper bracket further comprising a spring, spring
fastener, and upper vertebral contact surface; (b) One-piece lower
bracket further comprising lower vertebral contact surface and
spring guide track; wherein said upper bracket and said spring are
connected to each other via said spring fastener; said spring on
said upper bracket rests in said spring guide track on said lower
bracket, permitting said upper bracket to rotate axially on said
lower bracket; said upper bracket is suitable for attachment to an
upper spinal vertebrae via said upper vertebral contact surface;
said lower bracket is suitable for attachment to a lower spinal
vertebrae via said lower vertebral contact surface.
2. The artificial spinal disc replacement system of claim 1 wherein
said upper bracket further comprises lateral injection holes/ports
for adhesive.
3. The artificial spinal disc replacement system of claim 1 wherein
said lower bracket further comprises lateral injection holes/ports
for adhesive.
4. The artificial spinal disc replacement system of claim 1 wherein
said upper bracket, said spring, and said spring fastener are
integrated into a single unitary structure.
5. The artificial spinal disc replacement system of claim 1 wherein
said upper bracket comprises a plurality of springs.
6. The artificial spinal disc replacement system of claim 1 wherein
said lower bracket comprises a plurality of spring guide
tracks.
7. The artificial spinal disc replacement system of claim 1 wherein
said upper bracket is enlarged beyond a half-circle to permit
maximum surface contact with said upper spinal vertebrae.
8. The artificial spinal disc replacement system of claim 1 wherein
said lower bracket is enlarged beyond a half-circle to permit
maximum surface contact with said lower spinal vertebrae.
9. The artificial spinal disc replacement system of claim 1 wherein
said upper vertebral contact surface is convex.
10. The artificial spinal disc replacement system of claim 1
wherein said upper vertebral contact surface is concave.
11. The artificial spinal disc replacement system of claim 1
wherein said lower vertebral contact surface is convex.
12. The artificial spinal disc replacement system of claim 1
wherein said lower vertebral contact surface is concave.
13. The artificial spinal disc replacement system of claim 1
wherein said upper bracket further comprises a spherical bearing
which permits said spring fastener to engage said spring through a
hole in said spherical bearing.
14. The artificial spinal disc replacement system of claim 1
wherein said upper bracket further comprises a chamfered hole which
permits said spring fastener to engage said spring through said
chamfered hole in said upper bracket.
15. An artificial spinal disc replacement system comprising: (a)
Upper bracket further comprising a fusion block, fusion block
fastener, and upper vertebral contact surface; (b) Lower bracket
further comprising lower vertebral contact surface and fusion block
guide track; wherein said upper bracket and said fusion block are
connected to each other via said fusion block fastener; said fusion
block on said upper bracket rests in said fusion block guide track
on said lower bracket, permitting said upper bracket to be fixed to
said lower bracket; said upper bracket is suitable for attachment
to an upper spinal vertebrae via said upper vertebral contact
surface; said lower bracket is suitable for attachment to a lower
spinal vertebrae via said lower vertebral contact surface.
16. The artificial spinal disc replacement system of claim 15
wherein said upper bracket further comprises lateral injection
holes/ports for adhesive.
17. The artificial spinal disc replacement system of claim 15
wherein said lower bracket further comprises lateral injection
holes/ports for adhesive.
18. The artificial spinal disc replacement system of claim 15
wherein said upper bracket comprises a plurality of fusion
blocks.
19. The artificial spinal disc replacement system of claim 15
wherein said lower bracket comprises a plurality of fusion block
guide tracks.
20. The artificial spinal disc replacement system of claim 15
wherein said upper bracket is enlarged beyond a half-circle to
permit maximum surface contact with said upper spinal
vertebrae.
21. The artificial spinal disc replacement system of claim 15
wherein said lower bracket is enlarged beyond a half-circle to
permit maximum surface contact with said lower spinal
vertebrae.
22. The artificial spinal disc replacement system of claim 15
wherein said upper vertebral contact surface is convex.
23. The artificial spinal disc replacement system of claim 15
wherein said upper vertebral contact surface is concave.
24. The artificial spinal disc replacement system of claim 15
wherein said lower vertebral contact surface is convex.
25. The artificial spinal disc replacement system of claim 15
wherein said lower vertebral contact surface is concave.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This patent application is a continuation-in-part of United
States Patent Application for "ARTIFICIAL SPINAL DISC REPLACEMENT
SYSTEM AND METHOD", Ser. No. 11/544,136, docket DJC-2006-002 filed
on Oct. 9, 2006, and submitted to the USPTO via Express Mail on
Oct. 9, 2006 with tracking number ER618467378US. Applicant claims
benefit pursuant to 35 U.S.C. .sctn.120 of this Utility Patent
Application and hereby incorporates by reference this Utility
Patent Application. New matter contained in the current document is
generally illustrated in FIGS. 41-FIG. 51 and referencing text
contained herein.
[0002] Applicant claims benefit pursuant to 35 U.S.C. .sctn.119 and
hereby incorporates by reference Provisional Patent Application for
"ARTIFICIAL SPINAL DISC REPLACEMENT SYSTEM AND METHOD", Ser. No.
60/725,460, docket DJC-2005-001, filed Oct. 10, 2005, and submitted
to the USPTO with Express Mail on Oct. 10, 2005 with tracking
number ER618466616US.
PARTIAL WAIVER OF COPYRIGHT
[0003] All of the material in this patent application is subject to
copyright protection under the copyright laws of the United States
and of other countries. As of the first effective filing date of
the present application, this material is protected as unpublished
material.
[0004] However, permission to copy this material is hereby granted
to the extent that the copyright owner has no objection to the
facsimile reproduction by anyone of the patent documentation or
patent disclosure, as it appears in the United States Patent and
Trademark Office patent file or records, but otherwise reserves all
copyright rights whatsoever.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0005] Not Applicable
REFERENCE TO A MICROFICHE APPENDIX
[0006] Not Applicable
FIELD OF THE INVENTION
[0007] The field of the present invention relates to the use of
artificial spinal disc replacements, including systems and methods
associated with same, and generally includes apparatus associated
with United States Patent Classification 623/17.16 and methods of
installing these apparatus on patients.
DESCRIPTION OF THE PRIOR ART
Artificial Disc Replacement Revision
[0008] In a recent study, (a multi-center prospective clinical
trial of 688 patients, 375 of whom were randomized to receive
either a artificial disc or a single level lumbar spinal fusion),
although the rate of revision was 2% lower in the artificial disc,
the results showed that a revision may still be necessary in an
artificial disc replacement nearly as often as it is in traditional
spinal fusion surgery.
[0009] In clinical trials (one 2-year study recently presented to
the FDA panel) comparing artificial disc replacement to spinal
fusion surgery, results have already proven that artificial disc
patients were able to maintain flexibility, experienced
improvements in pain and functional ability, required shorter
hospital stays, and had greater satisfaction with the outcome of
their procedure.
Current State of the Art (0100, 0200)
[0010] There are currently several types of artificial disc
replacements on the U.S. market. Some of these artificial discs are
known as the Charite, Prodisc, Maverick, and the Bryan. There have
been other artificial discs in the past (such as the Acroflex), but
those have suffered distressing failure for the patients. Examples
of the present state of the art in spinal disc replacements are
generally illustrated in FIG. 1 (0100) extracted from U.S. Pat. No.
6,764,512 issued to Arnold Keller on Jul. 20, 2004 for PLASTIC
IMPLANT WITH CHANNEL FOR RADIOGRAPHIC CONTRAST WIRE, and FIG. 2
(0200) extracted from U.S. Pat. No. 6,726,720 issued to Raymond
Ross, Michael O'Neal, and Mark Boomer on Apr. 27, 2004 for MODULAR
DISC PROSTHESIS. FIG. 2 (0200) is commonly referred to as the
Charite spinal disc replacement, and is widely used in the arena of
spinal disc replacement.
Prior Art Surgical Procedures (0300)
[0011] The current procedure for performing the artificial disc
replacement is typically done with two surgeons, working together.
A general or vascular surgeon approaches the spine through and
incision in the abdomen (as generally illustrated in FIG. 3 (0300))
and carefully moves internal organs and blood vessels out of the
way (0311) to provide access to the spine (0301). Then a spine
surgeon uses special tools to remove the damaged disc and creates a
space between the two vertebrae for the implantation of the
artificial disc. The procedure general takes one to two hours, and
as illustrated in FIG. 3, is highly invasive and subjects the
patient (0310) to risks of infection and other surgical
complications.
[0012] In a spinal fusion surgery, the damaged disc is removed and
the vertebrae are joined together using bone grafts and metal screw
and/or cages so that motion can no longer occur in this area of the
spine. Often times with spinal fusion surgery, the bone graft used
to pack the disc space is bone that the surgeon has to remove from
the patient's hip. This means that the patient ends up having two
incisions, the second one being over the superior crest of the
ilium where the bone is harvested (scraped off). During recovery,
the patient may experience pain in the hip at the harvest site.
Patients usually have to wear a brace for about three months after
surgery and may need to be fitted with a bone stimulator to promote
healing at the fusion site.
BACKGROUND OF THE INVENTION
Overview (0300)
[0013] An intervertebral ("spinal") disc as generally illustrated
in FIG. 3 (0301) performs several functions including maintaining
normal intervertebral height ("spacer"), absorbing and transferring
forces of spinal disturbances ("shock absorber") and a fulcrum of
motion. A normal intervertebral disc is comprised of a gelatinous
central portion called the nucleus pulposus and surrounded by an
outer ligamentous ring called the annulus fibrosus. The gelatinous
nuclear material directs the forces of axial loading outward and
the annular fibers help distribute that force. The annulus fibrosus
has overlapping radial bands to "seal" the nucleus and allow
intradiscal pressures to rise as the disc is loaded, as well as
allow torsional stresses to be distributed through the annulus
under normal loading without rupture.
[0014] Unfortunately, injury to the spine or spinal discs is a
common occurrence in the workplace, resulting in significant pain
and suffering for patients so afflicted. About 65 million Americans
suffer from low back pain every year, according to the American
Association of Neurological Surgeons (AANS). Americans spend about
USD$50 billion each year on low back pain, which represents the
most common cause of job-related disability and lost work days in
the United States. More than 12 million people are reported to have
degenerative disc disease and more than 200,000 have lumbar spinal
fusion surgery every year. Lumbar spinal fusion surgery is a common
surgical treatment for low back pain or degenerative disc disease
and is often effective in reducing pain, but it limits
range-of-motion (ROM) and may transfer extra stress to discs above
and below the fusion site.
Spinal Disc Injury Overview
[0015] The vertebral column has 24 individual vertebrae arranged in
cervical, thoracic and lumbar regions. The sacral and coccygeal
vertebrae are fused. The seven mobile cervical vertebrae support
the neck and the (6-8 lb) head. The cervical spine is normally
curved into lordosis. The twelve thoracic vertebrae support the
thorax, head, and neck. They articulate with the 12 ribs
bilaterally. The thoracic spine is curved into kyphosis. The five
lumbar vertebrae support the upper body, torso and low back. The
column of these vertebrae becomes curved at the onset of walking
(1-2 years of age) into lordosis. The sacrum is the keystone of a
weight bearing arch involving the hip bones. The vertebral
curvatures may be affected (usually exaggerated) by posture,
activity, obesity, pregnancy, trauma, and/or disease. A
significant, possibly disabling, lateral curve of the spine which
may occur for many reasons is called scoliosis.
[0016] The intervertebral disc consists of the annulus fibrosus
(concentric interwoven collegenous fibers integrated with cartilage
cells) attached to the vertebral bodies above and below, and the
more central nucleus pulposus (a mass of degenerated collagen,
proteoglycans and water). The discs make possible movement between
the vertebral bodies. With aging, the discs dehydrate and thin,
resulting in a loss of disc height. The cervical and lumbar discs,
particularly, are subject to early degeneration from one or more of
a number of causes. Weakening and/or tearing of the annulus can
result in a broad-based bulge or a localized (focal) protrusion of
the nucleus and adjacent annulus. As such, this event can compress
a spinal nerve root.
[0017] Each pair of individual, unfused vertebrae constitutes a
motion segment, the basic movable unit of the back. Combined
movements of motion segments underlie movement of the neck and the
middle and low back. Each pair of vertebrae in a motion segment,
except C1-C2, is attached by three joints: a partly movable,
intervertebral disc anteriorly, and a pair of gliding synovial
facet (zygapophyseal) joints posteriorly. Ligaments secure the
bones together and encapsulate the facet joints (joint capsules).
The vertebral or neural canal transmits the spinal cord. The spinal
cord is the lower extension of the central nervous system. It takes
off from the medulla oblongata at the foramen magnum of the skull
and ends as the conus medullaris at the vertebral level of L1 or
L2. It bulges slightly in the lower cervical and lumbar segments
where it gives off the roots of spinal nerves destined for the
upper and lower limbs, respectively. The cord is ensheathed by
three coverings (meninges): the inner pia mater, arachnoid, and the
outer dura mater. The spinal cord is a center for spinal reflexes,
a source of motor commands for muscles below the head, and a
receiver of sensory input below the head. Located bilaterally
between each pair of vertebral pedicles are passageways, each
called intervertebral foramen, that are transmitting the spinal
nerves from the spinal cord. Spinal nerves are collections of axons
of sensory and motor neurons located in or adjacent to the spinal
cord. Spinal nerves arise from nerve roots that come directly off
the spinal cord. Thirty-one pairs of spinal nerves supply the body
structure with sensory and motor innervation, except for those
areas covered by the cranial nerves. From above to below, there are
8 cervical spinal nerves (C1-C8), 12 thoracic (T1-T12), 5 lumbar
(L1-L5), 5 sacral (S1-S5), and one coccygeal (Co1).
[0018] The planes (orientation) of the articular facets determine
the direction and influence the degree of motion segment movement.
The plane of the cervical facets is angled coronally off the
horizontal plane about 30 degrees. Considerable freedom of movement
of the cervical spine is permitted in all planes (sagital, coronal,
horizontal). The thoracic facets lie more vertical in the coronal
plane and are virtually non-weightbearing. The range-of-motion here
is significantly limited in all planes, less so in rotation. The
plane of the lumbar facets is largely sagittal, resisting rotation
of the lumbar spine, transitioning to a more coronal orientation at
L5-S1. The L4-L5 facet joints permit the greatest degree of lumbar
motion in all planes.
[0019] Extension of the weight bearing joints is an anti-gravity
function and extensor muscles of these joints tend to keep the
standing body vertically straight. The center of gravity of an
average human being standing with perfect posture is just anterior
to the motion segment of S1-S2. Flexion of the neck and torso moves
the center of gravity forward, loading the posterior cervical,
thoracic and lumbar paraspinal extensor muscles. The muscles acting
on the vertebral column, hip, knee and ankle joints make possible
erect standing walking and running postures.
[0020] The deep muscles of the back and posterior neck extend,
rotate or laterally flex one or more of the 24 paired facet joints
and the 22 intervertebral disc joints of the vertebral column. The
long muscles move several motion segments with one contraction,
while short muscles can move one or two motion segments at a time.
The erector spinae group comprises the principal extensors of the
vertebral motion segments. Oriented vertically along the
longitudinal axis of the back, they are thick, quadrilateral
muscles in the lumbar region, splitting into smaller, thinner
separate bundles attaching to the ribs, and upper vertebrae and
head. Erector spinae arises from the lower thoracic and lumbar
spines, the sacrum, ilium, and intervening ligaments. The
transversospinalis group extends the motion segments of the back
and rotates the thoracic and cervical vertebral joints.
[0021] These muscles generally run from the transverse processes of
one vertebra to the spine of the vertebra above, spanning three or
more vertebrae. The semispinales are the largest muscle of this
group, reaching from mid-thorax to the posterior skull, the
multifidi consist of deep fasciculi spanning 1-3 motion segments
from sacrum to C2. The rotators are well defined only in the
thoracic region. The small, deep-lying muscles cross the joints of
only one motion segment. They are collectively major postural
muscles. Electromyographic evidence has shown that these short
muscles remain in sustained contraction for long periods of time
during movement and standing/sitting postures. They are most
prominent in the cervical and lumbar regions.
[0022] The neck is a complex tubular region of muscles, viscera,
vessels and nerves surrounding the cervical vertebrae. The muscles
of the neck are arranged in superficial and deep groups. The
anterior and lateral muscle groups are divided into triangular
areas by the sternocleidomastoid muscle. The posteriolateral border
is the trapezius muscle.
[0023] Biomechanical studies have shown that people bear load
through the middle and posterior thirds of the disc. Spinal
researchers have measured the amount of sliding and tilting at
healthy spinal joints. During motions, the joint can be injured
with stresses of only 6-7 kg and, in some cases, the disc could be
injured and in others, a ligament might be injured. As our spine
becomes older, it goes through certain changes related to its age
through the process of simple wear and tear. The disc becomes
thinner and more brittle and even cracked in places and they lose
their elasticity and water content thus becoming less of a spinal
stabilizer.
[0024] It is a prevalent misconception that most disc herniations
result from a single event or trauma, microtrauma, primarily from
repetitive flexion and rotation movement, leads to a degenerative
cascade that frequently results in a herniated nucleus pulposus.
While the clinical presentation of disc herniation varies because
of the level size and position of the herniation, there are commons
signs and symptom patterns that exist. About 80% of the population
experience pain with radiation into the extremity along the
anatomic distribution of the affected nerve root. Neural
compression or irritation may precipitate motor weakness, reduced
reflexes, and sensory loss. Compensatory posturing frequently
occurs. About 90% of all lumbar disc herniations occur at the L4-L5
and L5-S1 levels.
[0025] Conservative treatment varies and includes traction, manual
therapy techniques, electrotherapeutic modalities, other physical
agents, dynamic muscular stabilization through physical therapy
exercise, functional restorative education, and pharmacologic
intervention (including oral or transdermal analgesics, NSAIDS,
muscle relaxers, oral corticosteroids, and/or epidural steroids).
Failure to respond to an active conservative treatment regimen for
at least six weeks is just one of the indications for lumbar
discectomy. Additional rationales for lumbar discectomy include
severe, incapacitating pain that eludes all forms of medicinal and
physical pain control measures, recurrent episodes of sciatica,
significant neurologic deficit with significant positive straight
leg raise test, bowel and bladder involvement, and progressive
neurologic deficit are some of the strong indications for surgical
intervention. The goals of rehabilitation are focused on return to
maximal functional status and include reduction of pain frequency
and intensity; maintenance of mobility; maximizing paraspinal
strength, flexibility and conditioning; and prevention of
recurrence of injury.
[0026] Discectomy via laminectomy is gradually being replaced by
lumbar microdiscectomy as the standard of care for the surgical
treatment of lumbar disc herniation. Other minimally invasive
surgical techniques addressing lumbar disc herniation include
percutaneous and endoscopic discectomy. Microdiscectomy offers
advantages over the traditional laminectomy and discectomy by
combining a smaller surgical exposure with far superior
visualization of the operating field. Moreover, this less invasive
surgical approach results in decreased perioperative bleeding and
hematoma formation and less paraspinal muscle dennervation and
fibrosis. Improved visualization of the operating field allows for
more precision in surgical technique, better nerve decompression,
less chance of iatrogenic injury and a reduction in the amount of
peridural scar tissue formed postoperatively. All these benefits
lead to less postoperative pain and morbidity and a shorter
hospital stay for the patient.
[0027] There has been a rapid evolution in the development and use
of spinal fixation devices for lumbar spine fusion surgery. They
are simply categorized as anterior or posterior fixation devices.
The most common and most controversial fixation devices are the
pedicle screw and rod/plate systems. Anterior fixation devices
include screw and rod/plate systems as well as interbody cages.
Essentially, these devices are hollow cylinders made of titanium,
carbon, or bone. The cages are filled with autogenous bone graft
and inserted between vertebral bodies. The patient's autogenous
iliac crest is the standard source of bone graft material to fill
the interbody cage. The goal of lumbar fusion is the union of two
or more vertebrae. Most patients with interbody fixation become
mobile and more independent than those with a non-instrumented
spinal fusion, but the patients must wear a post-operative lumbar
orthosis for an extended period and therefore require an extensive
recovery time.
[0028] Different surgeons use different techniques to perform a
lumbar fusion. The traditional approach is through a midline
posterior incision. The posterior lumbar interbody fusion (PLIF) is
a particularly demanding procedure associated with higher incidence
of post-surgical nerve injuries than the posterolateral fusion.
Some surgeons have moved to using an anterior approach (ALIF), but
the ALIF cannot stand alone to withstand the forces of daily
patient use and surgeons have found that, in order to prevent
collapse or lack of fusion altogether, they have to protect the
graft with posterior instrumentation which is placed either on the
same day of surgery or in another procedure. A "360"
circumferential fusion is also done in this manner.
OBJECTIVES OF THE INVENTION
Deficiencies in Prior Art Addressed
[0029] The common approach to stabilizing damaged or disrupted
intervertebral discs is to fuse the vertebrae above and below the
damaged disc. Although proven as a successful approach to
permanently stabilize the injured area, fusion has the following
drawbacks: [0030] Fusion unnecessarily eliminates a portion of the
spine's normal range-of-motion (ROM); [0031] Fusion increases the
stressors imposed on the adjacent mobile vertebra; [0032] Fusion
often causes subsequent breakdown of the intervertebral disc above
and below the fused vertebrae; [0033] Fusion causes osteophyte
formation at the levels adjacent to the fusion; [0034] Almost half
of patients still have lumbar pain after the fusion procedure.
[0035] The present invention allows for preservation of the
intervertebral disc space without immobilization of the vertebrae,
thereby reducing the risk of breakdown of the adjacent vertebrae
above and below and allowing full ROM at the level of the damaged
disc.
[0036] By using special instrumentation and scopes with the present
invention, implantation through laparoscopic spinal surgery
requires only three to four small incisions, much like those a
patient might experience when having another minor surgery such as
a cholecystectomy or appendectomy. There are numerous benefits of
this minimally invasive surgery versus surgical incisions made with
traditional fusion surgery. The most significant benefit is a
reduced hospital stay and reduced recuperation time.
Exemplary Invention Objectives
[0037] One skilled in the art will recognize that the present
invention provides significant improvements to the patient as
compared to the prior art. Accordingly, the objectives of the
present invention are (among others) to circumvent the deficiencies
in the prior art. Some of these benefits which may be present in
some embodiments include (but are not limited to) the following
objectives: [0038] To provide an ARTIFICIAL SPINAL DISC REPLACEMENT
SYSTEM AND METHOD that overcomes the deficiencies in the prior art.
[0039] Preservation of ROM in the patient. [0040] The replacement
disc will remain secure without the need for screws into the spinal
vertebrae. [0041] The procedure to install the invention may be
laparoscopic, thereby alleviating the need for major patient
surgery. As an alternative, minimally invasive surgery may be
utilized using a lateral insertion procedure. [0042] The present
invention will reduce the need for expensive post-operative care
(physical therapy, hospital, physician visits, etc.). [0043] All
repairs to the invention can be done laparoscopically. As an
alternative, minimally invasive surgery may be utilized using a
lateral insertion procedure. [0044] The present invention is
modular and can be used in cervical or lumbar region and
potentially thoracic regions of the spine. [0045] The present
invention will rotate within limitations of the guide tracks.
[0046] The present invention will allow bending of vertebrae for
forward flexion, extension, and lateral flexion. [0047] The present
invention can be made of any material that will allow for optimum
spine function. The material selection for any component described,
implied, or suggested herein can be manufactured using any surgical
or bio-compatible materials, including but not limited to the use
of LIQUID METAL.RTM. or any version or chemical compositions
thereof. [0048] The present invention can consist of brackets and
spring design. [0049] The present invention brackets can be
attached with an adhesive. [0050] The present invention upper
bracket can have a protrusion which will be threaded to allow for
efficient attachment of the spring assembly. [0051] The present
invention spring assembly can be fully customizable for permanent
ROM limitations if necessary due to physical limitations of
existing vertebrae in the patient. [0052] The present invention
springs can be altered for elasticity for acceptable movement.
[0053] The present invention springs can be attached via
specialized fasteners. [0054] The present invention disc
replacement can consist of, but is not limited to, brackets and
springs and nuts. [0055] The present invention can be used in
osteoporotic, osteopenic, or normally aged bone. [0056] The present
invention will not interrupt biomechanical alignment of the spine.
[0057] The present invention can adjust the disc height to maintain
intervertebral space, or increase or decrease this spacing. [0058]
The present invention may incorporate a fusion block wherein three
blocks when attached to an upper bracket will not allow ROM to
occur thereby simulating a fusing of the vertebrae together. Each
of the fusion blocks in this configuration can occupy the complete
spring guide track and be secured by threaded projections located
in the upper brackets. [0059] The present invention may incorporate
miniaturization and/or enlargement of the upper and/or lower
bracket segments to provide increased stability for the implant.
[0060] The present invention anticipates integration of bracket
segments into a single-piece bracket of sufficient size to provide
implant stability. This integration may occur for the upper and/or
lower brackets. [0061] The present invention anticipates that the
orientation of the upper and/or lower bracket segments or unitary
upper and/or lower bracket's machined contours that interface with
the vertebrae surface may be in any orientation necessary for ease
of production and surgical installation. [0062] The present
invention permits the use of angled threaded projections, angled
spring guide tracks, and/or spherical bearings at each of the
threaded projections which allows for spinal wedge angle alignment
of the upper and/or lower brackets to the upper and/or lower
vertebrae securing spring and/or fusion block. This flexibility
permits custom fitting of the surgical implant to each individual
patient.
[0063] One skilled in the art will recognize that this list of
advantages is not exhaustive and may have application to some
embodiments of the present invention and not others. While these
objectives should not be understood to limit the teachings of the
present invention, in general these objectives are achieved in part
or in whole by the disclosed invention that is discussed in the
following sections. One skilled in the art will no doubt be able to
select aspects of the present invention as disclosed to affect any
combination of the objectives described above.
BRIEF SUMMARY OF THE PRESENT INVENTION
Contrast With Prior Art
[0064] The common approach to stabilizing damaged or disrupted
intervertebral discs is to fuse the vertebrae above and below the
damaged disc. Although proven as a successful approach to
permanently stabilize the injured area, fusion unnecessarily
eliminates a portion of the spine's normal range-of-motion,
increases the stressors imposed on the adjacent mobile vertebra,
often causing subsequent breakdown of the intervertebral disc above
and below the fused vertebrae, osteophyte formation at the levels
adjacent to the fusion, and almost half of patients still have
lumbar pain after the procedure. The present invention avoids these
drawbacks of the prior art and preserves full ROM in the
patient.
Overview (0400)
[0065] Artificial prosthesis have been commonly used to replace
painful joints in hips and knees for more than 20 years and these
are among the most successful and reliable operations performed
today. Securing these replacements has been done with a variety of
adhesives and/or bone glues. The present invention advances this
concept forward by teaching a spinal disc replacement system that
can be fixed to the spine vertebrae with adhesive using
laparoscopic techniques (0401) as illustrated in FIG. 4 (0400).
Placement (0500, 0600, 0700)
[0066] The present invention relates generally to a spinal implant
for use in intervertebral disc replacement. It is an articulating
implant that restores proper intervertebral spacing, preserves
spinal range-of-motion (ROM) and flexibility, and eliminates nerve
root and/or spinal cord compression. As illustrated in FIG. 5
(0500), the present invention (0810) (with suitable modifications
for size and placement) is applicable for use at any point (0501,
0502, 0503) along the spinal column (0510).
[0067] A more detailed depiction of the placement of the present
invention in the spinal column is illustrated in FIG. 6 (0600),
wherein the exemplary spinal disc replacement (0810) is inserted
between an upper (0601) and lower (0602) vertebrae in the spinal
column. As previously mentioned, the present invention is amenable
for used at any point along the spinal column. It is an
articulating implant that restores proper intervertebral spacing,
preserves spinal ROM and flexibility, and eliminates nerve root
and/or spinal cord compression.
[0068] Further detail of the present invention is generally
illustrated in the perspective view of FIG. 7 (0700), wherein an
exemplary embodiment (0810) is placed between two spinal vertebrae
(0701, 0702). While a wide variety of invention embodiments is
anticipated, the general placement as illustrated in FIG. 7
provides some insight into general application of the present
invention.
General Assembly and Component Breakdown (0800)
[0069] The present invention is generally illustrated in the
detailed exploded view of FIG. 8 (0800), wherein it is comprised of
an upper bracket (0801), lower bracket (0802), and spring(s) (0811)
separating the brackets (0801, 0802). The present invention will
allow for preservation of the intervertebral disc space without
immobilization of the vertebrae, thereby reducing the risk of
breakdown of the adjacent vertebrae above and below and allowing
full ROM at the level of the damaged disc.
[0070] The upper bracket (0801) and lower bracket (0802) are
generally not attached to the skeletal structure using screws as
had been done by many of the other disc replacements on the market
currently. Screws placed into fragile bone have the potential for
breaking the bone and causing failure of the hardware/spinal
replacement. Adhesive is much less invasive and has been proven
successful many times over in hip and shoulder replacement
surgeries worldwide. Upper (0831) and lower (0832) vertebral
contact surfaces provide adhesion surfaces for adhesive to mate the
upper/lower brackets to the corresponding upper/lower vertebrae.
The upper/lower brackets are designed to include a hole in the
bracket for adhesive/bone glue to be injected, as in item
(0841).
[0071] The brackets as illustrated can be constructed of a variety
of materials, including but not limited to titanium, chromium,
cobalt, or a variety of plastics. Research indicates that many
preferred exemplary embodiments employ material selection
(optimally a titanium alloy) that is selected to support a spring
specification of at least 1800 Newtons within the size of 3 to 8 mm
spring width.
[0072] Additionally, as is illustrated in FIG. 8 (0800) and in
other drawings, the system may be fabricated in multiple segments
for the upper (0851, 0861, 0871) and lower (0852, 0862, 0872)
brackets in a "jigsaw" or interlocking fashion to facilitate
assembly within the context of a laparoscopic surgical procedure.
The benefits of the modular design are that the disclosed spinal
disc replacement can be placed in either cervical, thoracic, or
lumbar areas and are adjustable for any body size.
BRIEF DESCRIPTION OF THE DRAWINGS
[0073] For a fuller understanding of the advantages provided by the
invention, reference should be made to the following detailed
description together with the accompanying drawings wherein:
[0074] FIG. 1 illustrates a prior art embodiment of an artificial
spinal disc implant extracted from U.S. Pat. No. 6,764,512 issued
to Arnold Keller on Jul. 20, 2004 for PLASTIC IMPLANT WITH CHANNEL
FOR RADIOGRAPHIC CONTRAST WIRE;
[0075] FIG. 2 illustrates a prior art embodiment of an artificial
spinal disc implant extracted from U.S. Pat. No. 6,726,720 issued
to Raymond Ross, Michael O'Neal, and Mark Boomer on Apr. 27, 2004
for MODULAR DISC PROSTHESIS;
[0076] FIG. 3 illustrates a typical surgical procedure associated
with prior art embodiments of artificial spinal disc implants;
[0077] FIG. 4 illustrates a preferred exemplary embodiment of the
present invention;
[0078] FIG. 5 illustrates a typical laparoscopic surgical procedure
associated with some preferred embodiments of the present
invention;
[0079] FIG. 6 illustrates a typical spinal disc placement
procedures associated with some preferred exemplary embodiments of
the present invention, FIG. 7 illustrates a side view of a
preferred exemplary embodiment of the present invention as
typically installed between two spinal vertebrae;
[0080] FIG. 8 illustrates a detail exploded view of a preferred
exemplary embodiment of the present invention illustrating the
major components of a typical embodiment of same;
[0081] FIG. 9 illustrates a detail back side view of a preferred
exemplary embodiment of the present invention as typically placed
on a lower spinal vertebrae;
[0082] FIG. 10 illustrates a perspective view of a preferred
exemplary embodiment of the present invention installed between two
spinal vertebrae;
[0083] FIG. 11 illustrates a perspective view of a preferred
exemplary embodiment of the present invention and details adhesive
injection holes/ports on the upper and lower brackets;
[0084] FIG. 12 illustrates an exemplary edge chamfer technique
useful in manufacturing some preferred exemplary embodiments of the
upper and/or lower bracket as taught by the present invention;
[0085] FIG. 13 illustrates an exemplary edge rounding technique
useful in manufacturing some preferred exemplary embodiments of the
upper and/or lower bracket as taught by the present invention;
[0086] FIG. 14 illustrates a bottom view of a preferred exemplary
embodiment of the present invention;
[0087] FIG. 15 illustrates a bottom perspective view of a preferred
exemplary embodiment of the bottom bracket used in some embodiments
of the present invention;
[0088] FIG. 16 illustrates a top exploded perspective view of a
preferred exemplary embodiment of the upper bracket used in some
embodiments of the present invention;
[0089] FIG. 17 illustrates a bottom exploded perspective view of a
preferred exemplary embodiment of the upper bracket used in some
embodiments of the present invention, showing the lateral view of
the upper bracket of the spinal implant including the vertebral
contact surface, cylindrical threaded projection, nut, spring and
the insertion holes for adhesive;
[0090] FIG. 18 illustrates a bottom perspective view of a preferred
exemplary embodiment of the upper bracket used in some embodiments
of the present invention;
[0091] FIG. 19 illustrates a preferred exemplary embodiment of the
lower bracket used in some preferred embodiments of the present
invention, showing the lateral view of the lower bracket of the
spinal implant including vertebral contact surface, spring guide
track, inset overhang of the guide track, the insertion holes for
adhesive;
[0092] FIG. 20 illustrates the lateral view of the spring guide
track in the lower bracket vertebral contact surface with springs
from the upper bracket assembly properly positioned;
[0093] FIG. 21 illustrates a side view of a preferred exemplary
embodiment of the upper bracket of the present invention;
[0094] FIG. 22 illustrates a front view of a preferred exemplary
embodiment of the top and bottom bracket assemblies and springs of
the present invention;
[0095] FIG. 23 illustrates a side view of a preferred exemplary
embodiment of the top and bottom bracket assemblies and springs of
the present invention;
[0096] FIG. 24 illustrates a back sectional view of a preferred
exemplary embodiment of the top and bottom bracket assemblies of
the present invention as applied to a typical spinal upper and
lower vertebrae;
[0097] FIG. 25 illustrates an exploded view of a preferred
exemplary embodiment of the present invention using screw/nut
fasteners for the springs;
[0098] FIG. 26 illustrates a side sectional view of the preferred
exemplary embodiment illustrated in FIG. 25;
[0099] FIG. 27 illustrates an exploded view of a preferred
exemplary embodiment of the present invention using screw/"U"
bracket fasteners as an alternative spring fastening means;
[0100] FIG. 28 illustrates a side sectional view of the preferred
exemplary embodiment illustrated in FIG. 27;
[0101] FIG. 29 illustrates an exploded view of a preferred
exemplary embodiment of the present invention using rivet fasteners
for the springs;
[0102] FIG. 30 illustrates a side sectional view of the preferred
exemplary embodiment illustrated in FIG. 29;
[0103] FIG. 31 illustrates an exploded view of a preferred
exemplary embodiment of the present invention using threaded
projections common to the upper bracket and nut fasteners for the
springs;
[0104] FIG. 32 illustrates a side sectional view of the preferred
exemplary embodiment illustrated in FIG. 31;
[0105] FIG. 33 illustrates a preferred exemplary embodiment of the
present invention wherein the lower bracket is non-co-planar;
[0106] FIG. 34 illustrates a side sectional view of the preferred
exemplary embodiment illustrated in FIG. 33;
[0107] FIG. 35 illustrates a preferred exemplary embodiment of the
present invention wherein the upper/lower bracket vertebral contact
surface has been partially surface conditioned to promote improved
adhesion to the upper spinal vertebrae;
[0108] FIG. 36 illustrates a preferred exemplary embodiment of the
present invention wherein the upper/lower bracket vertebral contact
surface has been fully surface conditioned to promote improved
adhesion to the upper spinal vertebrae;
[0109] FIG. 37 illustrates a preferred exemplary embodiment of the
present invention wherein the upper/lower bracket vertebral contact
surface has been partially knurled to promote improved adhesion to
the upper spinal vertebrae;
[0110] FIG. 38 illustrates a preferred exemplary embodiment of the
present invention wherein the upper/lower bracket vertebral contact
surface has been fully knurled to promote improved adhesion to the
upper spinal vertebrae;
[0111] FIG. 39 illustrates an alternative preferred exemplary
embodiment of a spring structure suitable for use in some preferred
exemplary embodiments of the present invention;
[0112] FIG. 40 illustrates a preferred exemplary method embodiment
of a surgical procedure useful in installing some embodiments of
the present invention;
[0113] FIG. 41 illustrates a perspective view of a preferred
exemplary embodiment of the present invention wherein the upper
bracket is of unitary (one-piece) construction and utilizes
spherical bearings to achieve attachment of the springs via the
spring fasteners;
[0114] FIG. 42 illustrates a side view of a preferred exemplary
spherical bearing/spring fastener/spring structure as utilized in
the preferred exemplary embodiment of FIG. 41;
[0115] FIG. 43 illustrates a detailed side assembly view of a
preferred exemplary spherical bearing/spring fastener structure as
utilized in the preferred exemplary embodiment of FIG. 41;
[0116] FIG. 44 illustrates an alternate side view of a preferred
exemplary spherical bearing/spring fastener/spring structure as
utilized in the preferred exemplary embodiment of FIG. 41;
[0117] FIG. 45 illustrates a side view of an alternative to the
spherical bearing structure illustrated in FIGS. 41-44, wherein the
upper bracket utilizes a chamfered receiving machine screw socket
capable of permitting movement of the spring fastener as it is
attached to the upper bracket;
[0118] FIG. 46 illustrates a perspective view of a preferred
embodiment of the present invention lower bracket wherein the
bracket further comprises unitary construction and the use of
fusion blocks to mate to the lower bracket;
[0119] FIG. 47 illustrates an alternate perspective view of a
preferred embodiment of the present invention lower bracket wherein
the bracket comprises unitary construction, enlarged (larger than
half-circle) surface area, and side injection ports to permit
application of adhesive;
[0120] FIG. 48 illustrates an alternate perspective assembled view
of a preferred embodiment of the present invention lower bracket
and springs wherein the bracket comprises unitary construction and
side injection ports to permit application of adhesive;
[0121] FIG. 49 illustrates a top view of a preferred embodiment of
the present invention lower bracket wherein the bracket size is
extended from other embodiments to provide additional support over
the spinal column;
[0122] FIG. 50 illustrates an alternative preferred exemplary
embodiment wherein the upper and/or lower bracket incorporates side
injection ports to permit application of bone adhesive from the
side of the patient;
[0123] FIG. 51 illustrates a side sectional view of a preferred
exemplary embodiment of the present invention wherein the upper
and/or lower bracket is non-co-planar and the vertebrae mating
surface is convex.
[0124] Referring now in detail to the figures wherein like
reference numbers like parts throughout, preferred forms of the
present invention will now be described.
DESCRIPTION OF THE PRESENTLY PREFERRED EXEMPLARY EMBODIMENTS
[0125] While the present invention is susceptible of embodiment in
many different forms, there is shown in the drawings and will
herein be described in detailed preferred embodiment of the
invention with the understanding that the present disclosure is to
be considered as an exemplification of the principles of the
invention and is not intended to limit the broad aspect of the
invention to the embodiment illustrated.
[0126] The numerous innovative teachings of the present application
will be described with particular reference to the presently
preferred embodiment, wherein these innovative teachings are
advantageously applied to the particular problems of an ARTIFICIAL
SPINAL DISC REPLACEMENT SYSTEM AND METHOD. However, it should be
understood that this embodiment is only one example of the many
advantageous uses of the innovative teachings herein. In general,
statements made in the specification of the present application do
not necessarily limit any of the various claimed inventions.
Moreover, some statements may apply to some inventive features but
not to others.
Fastener Coatings Not Limitive
[0127] While several preferred embodiments may incorporate special
coatings on fasteners to promote integration into the spinal column
or to promote self-locking of the fastener, the present invention
scope is not limited by the specific fastener coatings listed
herein.
Fastener Configuration Not Limitive
[0128] In many preferred exemplary embodiments, the spinal implant
disclosed herein may make use of a variety of fasteners for
fixation of springs used between the upper/lower brackets. One
skilled in the art will recognize that the exact fastener style may
be determined by a variety of factors and is not necessarily
limited to the exact configurations detailed herein. Fastener
styles including but not limited to fastener head, fastener body,
threading, recesses, locking mechanisms, and the like may be varied
without loss of generality in the teachings of the present
invention. Therefore, the term "fastener" or "fastening" should be
given its broadest definition within the context of the teachings
of the present invention.
Location Not Limitive
[0129] The present invention is designed to be implemented as a
spinal disc replacement, and within this context a variety of
location placements within the spinal column are generally
illustrated within this document. However, nothing within this
description is intended to limit the scope of placement of the
spinal disc replacement, and the teachings of the present invention
may be applied (with appropriate structural modification to account
for location) to placement within any portion of the patient's
spinal column. The drawings and written description should not in
any way limit the scope of where the invention may be applied with
respect to placement within the spinal column.
Surface Conditioning Not Limitive
[0130] In some preferred embodiments the vertebral contact surfaces
are conditioned for advantageous adhesion between the contact
surface and the associated spinal vertebrae via the use of adhesive
or some other fastening means. While several exemplary methods of
surface conditioning are illustrated herein, the scope of the
invention is not limited by any specific method mentioned herein,
as one skilled in the art can enumerate a variety of such
methods.
Fastener Orientation Not Limitive
[0131] Additionally, the present invention should not be limited in
scope by the orientation of fasteners which are illustrated in the
attached drawings and described herein. One skilled in the art will
recognize that fastener orientation may in many circumstances be a
preferential decision that is not directly tied to the function of
the invention or the scope of the disclosed invention. As such,
fastener orientation should not limit the invention scope.
Fabrication Materials Not Limitive
[0132] The elements of this spinal implant can be fabricated from
biocompatible materials including, without limitation, LIQUID
METAL.RTM., titanium, surgical alloys, surgical metals, stainless
steel, chrome-molybdenum alloy, cobalt-chromium alloy, zirconium
oxide ceramic, non-absorbable polymers, polymer compounds, and
other anticipated biocompatible metallic or polymeric materials, or
any version or chemical composition thereof. One skilled in the art
will recognize that the teachings of the present invention are not
limited by the type of material used in the manufacture of the
disclosed spinal disc replacement.
Fixative Not Limitive
[0133] In many preferred exemplary embodiments, the spinal implant
disclosed herein makes use of an adhesive for fixation to adjacent
vertebrae within the spinal column. One skilled in the art will
recognize that the teachings of the present invention are not
limited by the type of adhesive or fixative means used in the
installation of the disclosed spinal disc replacement. While
adhesive is clearly the preferred method of attachment in some
preferred embodiments, one skilled in the art will recognize that
other fixation means, including but not limited to screws, clasps,
or other fixation means may be possible without limiting the
teachings of the present invention.
Spring Fixation Not Limitive
[0134] In many preferred exemplary embodiments, the spinal implant
disclosed herein may make use of cylindrical threaded projections,
bolts, nuts, or other fasteners for fixation of springs used
between the upper/lower brackets. One skilled in the art will
recognize that the teachings of the present invention are not
limited by the means by which the springs are fastened to the upper
or lower bracket. One skilled in the art will recognize that the
spring feature taught by the present invention can also be
integrated into the fabrication of the upper/lower bracket itself,
with no loss of generality in the disclosed invention.
Component Part Count Not Limitive
[0135] While the component count illustrated and discussed herein
may be applicable to many preferred embodiments, the present
invention anticipates that components may be sectioned or combined
in many embodiments not illustrated.
Surface Coatings Not Limitive
[0136] In many preferred exemplary embodiments, the spinal implant
disclosed herein may make use of a variety of material coatings
such as nylon, Teflon.RTM., or other materials to reduce friction
between moving parts or improve overall long term wear
characteristics of the spinal implant. One skilled in the art will
recognize that the teachings of the present invention are not
limited by any surface coatings which may be applied to any of the
components described by the teachings of the present invention.
Orientation Not Limitive
[0137] In many preferred exemplary embodiments, the spinal implant
disclosed herein comprises an upper bracket having springs which
rest in spring guide tracks that are formed within a lower bracket,
the upper/lower bracket structure being connected respectively to
upper/lower vertebrae via vertebral contact surfaces on the
upper/lower brackets. Note, however, that the orientation of the
structure is not critical, and the orientation of the upper/lower
bracket may be swapped such that the upper bracket contains the
spring guide tracks and the lower bracket contains the springs.
[0138] Furthermore, one skilled in the art will recognize that
while the present invention discloses a single spring guide track,
the present invention may incorporate multiple spring guide tracks,
and these tracks may reside on one or more of the upper/lower
brackets. The present invention specifically anticipates situations
in which the spring guide tracks are on both upper and lower
brackets, with springs being placed to mate to these guide tracks
on the bracket not containing the particular guide track.
[0139] Thus, the springs illustrated herein and their associated
guide tracks may be replicated/mirrored with no loss of generality
in the teachings of the present invention.
Spinal Interface Not Limitive
[0140] In many preferred exemplary embodiments, the spinal implant
disclosed herein may make use of an irregular spinal interface as
generally illustrated in the drawings. One purpose of such an
irregular interface is to promote adhesion to the spinal column
when the system is fixed to the spinal column using adhesive.
However, one skilled in the art will recognize that the teachings
of the present invention are not limited by any particular surface
interface as generally illustrated in the drawings, and that other
spinal interface structures (including flat) may be suitable in
some circumstances without departing from the teachings of the
present invention.
Multi-Part Construction Not Limitive
[0141] The present invention as illustrated herein may be comprised
of an upper and lower bracket, with each of these assemblies being
composed of a plurality of sections that are assembled together
during a typical laparoscopic surgical procedure. While the
examples illustrated herein comprise three upper bracket sections
and three lower bracket sections, nothing within the scope of the
present invention teachings limits the structure to this
configuration. The upper/lower brackets may have one or more
sectional pieces and may or may not be assembled within the patient
during surgery.
Springs Not Limitive
[0142] One skilled in the art will recognize that the springs
detailed in this disclosure are illustrative only, and do not limit
the scope of the claimed invention. "Spring" or "springs" in the
context of this disclosure include any material or structure
capable of absorbing shock, torsional stress, thrust, or extended
wear. This definition includes the field of bearings and the like
which are capable of supporting a range of rotational motion.
Nothing in the present invention limits the scope to configurations
with a plurality of springs, although many preferred embodiments
exhibit multiple springs. One skilled in the art will recognize
that a wide variety of materials consistent with the application of
Hooke's Law can operate as a spring and would be applicable to the
teachings of the present invention.
Spring Guide Tracks Not Limitive
[0143] One skilled in the art will recognize that the spring guide
tracks detailed in this disclosure are illustrative only, and do
not limit the scope of the claimed invention. "Spring guide tracks"
in the context of this disclosure include any material or structure
capable of supporting and/or retaining a "spring" retained by the
bracket not containing the spring guide track. Nothing in the
present invention limits the scope to configurations with a
plurality of spring guide tracks, although many preferred
embodiments exhibit multiple spring guide tracks. One skilled in
the art will recognize a variety of methods by which a spring may
rest in or be retained by a spring guide track, and the
illustrations provided herein are only exemplary of the wide
variety of methods by which this may be accomplished.
Surgical Technique Not Limitive
[0144] In many preferred exemplary embodiments, the spinal implant
disclosed herein may be installed using laparoscopic surgical
techniques. However, one skilled in the art will recognize that the
teachings of the present invention are not limited by any
particular surgical technique, and that the present invention may
be installed using a variety of surgical techniques without loss of
generality in the teachings of the present invention.
Upper Bracket Construction Not Limitive
[0145] In many preferred exemplary embodiments, the spinal implant
disclosed herein may have an upper bracket structure further
comprising springs, spring fasteners, and upper vertebral contact
surface. The present invention specifically anticipates that this
upper bracket structure may in some configurations combine as a
unified structure the springs and spring fasteners within the
context of the upper bracket. One skilled in the art will recognize
that the upper bracket may be fabricated from material in which the
springs are integrated into the product, eliminating the need for
separate springs and/or spring fasteners.
Adhesive Not Limitive
[0146] The terms "adhesive" and "adhesive agent" should be given
broad definitions within the context of this disclosure. One
skilled in the art will recognize that a variety of adhesive means
are available for fixing the upper and/or lower brackets to their
respective vertebrae, including but not limited to bone glue, bone
cement, or other available bioadhesive substances. A particular
adhesive may be chosen based on the embodiment of the present
invention manufactured, as is well known in the art.
Edge Chamfering/Rounding Not Limitive
[0147] The present invention detailed herein may incorporate in
several preferred embodiments edge chamfering and/or rounding of
edged to promote optimal operation of the spinal disc replacement
and/or improved compatibility with insertion into the spinal
column. One skilled in the art will recognize that the general
concept of edge deburring and the like are well known in the art
and may be applied to a wide scope of the teachings of the present
invention, depending on the particular application. The scope of
the present invention is not to be limited in any way by any
examples of edge deburring, chamfering, rounding, or the like as
illustrated herein.
Co-Planar Disc Structure Not Limitive
[0148] The present invention may be implemented using co-planar
upper/lower brackets as illustrated herein in some preferred
exemplary embodiments. However, the invention may incorporate
non-planar (non-co-planar) disc structures in which the upper
and/or lower bracket is tapered rather than co-planar, permitting
the replacement disc structure to more fully conform to the
requirements of the replaced disc in the patient.
[0149] Therefore, nothing in the invention disclosure herein should
be construed as limiting the scope of the present invention to
co-planar upper and/or lower brackets. One skilled in the art will
recognize situations in which non-co-planar upper and/or lower
brackets are dictated by patient requirements.
General System Description (0800)
[0150] As generally seen in FIG. 8 (0800), the general spinal disc
replacement system comprises an upper bracket (0801), which further
comprises spring(s) (0811), and vertebral contact surfaces (0831,
0832). The vertebral contact surfaces (0831, 0832) provides a
permanent and rigid connection between the implant and the skeletal
structure. The vertebral contact surfaces (0831, 0832) are in many
preferred embodiments segmented (0851, 0861, 0871, 0852, 0862,
0872) for ease of installation and providing the ability to use
laparoscopic surgical insertion. The upper bracket (0801) mates to
a corresponding lower bracket (0802), which has one or more spring
guide track(s) (0812) in which the spring(s) (0811) from the upper
bracket (0801) ride and in which the springs (0811) are
retained.
Fastening Means
[0151] While a wide variety of fastening means may be used to
attach the spring(s) (0811) to the upper bracket (0801), several
exemplary fastener types are illustrated in the drawings, including
screws (0821) and nuts (0822). While recessed machine screws are
preferred in some embodiments, one skilled in the art will
recognize that a wide variety of other fastening means would be
equally appropriate. One variation not illustrated in FIG. 8 (0800)
would include the use of threaded cylindrical projections (studs)
that are inserted into the upper bracket (0801) and onto which nut
fasteners (0822) are attached to affect spring retention. The use
of "shoulder bolts" or cylindrical fasteners with partial shaft
threading is also specifically anticipated. One skilled in the art
will recognize that this alternate form of cylindrical threaded
projection could encompass a stud screwed into the upper bracket or
some form of integrated machined threaded cylinder emanating from
the upper bracket with no loss of generality in the teachings of
the present invention.
[0152] Each individual segment of the vertebral contact surface may
contain a cylindrical, threaded projection at it's midpoint on the
inferior surface. The cylindrical, threaded projection may hold the
nut upon application of the spring (0811). Also located at the
midpoint but on the lateral surface are insertion holes on each
segment. The three segments of the vertebral contact surface
component of the upper bracket are meant to conjoin together to
comprise the single unit of the upper bracket in some preferred
embodiments. The upper/lower brackets extend from the outer edge of
the skeletal structure to the interior, inferior surface of the
vertebral body, but generally do not exceed the diameter of the
vertebral body.
[0153] Either end of the vertebral contact surface (0831, 0832)
will be angled toward the skeletal structure so that the surfaces
are flush, making a cavity into which adhesive can be filled. The
under surface of the bracket that contacts the skeletal surface can
be textured/hatched to allow for maximum surface area to improve
adhesion of the implant to the bone. The adhesive can be injected
through the insertion holes (0841, 0842) on the lateral surface of
each segment.
Perspective Installation Views (0900, 1000)
[0154] FIG. 9 (0900) and FIG. 10 (1000) provide perspective views
of a presently preferred embodiment of the present invention (0810)
as installed within the spinal column. FIG. 9 (0900) provides a
patient-back perspective view of the present invention (0810) as it
rests on the lower vertebrae (0902). FIG. 10 (1000) provides a
perspective view of a presently preferred embodiment of the present
invention (0810) as installed between an upper (1001) and lower
(1002) vertebrae in a typical spinal column.
Perspective Component Views (1100, 1200, 1300, 1400, 1500)
[0155] FIG. 11 (1100), FIG. 12 (1200), FIG. 13 (1300), FIG. 14
(1400), and FIG. 15 (1500), provide perspective component views of
a presently preferred embodiment of the present invention (0810).
These figures will now be discussed individually.
[0156] FIG. 11 (1100) illustrates a perspective view of a presently
preferred embodiment of the present invention, and illustrates
injection holes/ports for adhesive in the upper (0841) and lower
(0842) bracket.
[0157] FIG. 12 (1200) and FIG. 13 (1300) illustrate cross sections
of typical chamfering or rounding which may be implemented at the
edges of any portion of the present invention to facilitate
cohesive placement within the spinal column with minimum disruption
of patient ROM. Note that one skilled in the art could apply the
depicted chamfering/rounding or other well known edge detailing
techniques to any portion of the upper and/or lower bracket
structured depicted within this disclosure.
[0158] FIG. 14 (1400) and FIG. 15 (1500) illustrate perspective
views of a presently preferred exemplary embodiment of the upper
and/or lower bracket vertebral interfaces. These perspective views
illustrate how the adhesive injection holes/ports (0841, 0842) as
generally illustrated in FIG. 8 (0800) extend through the body
(1401, 1402, 1403) of the brackets to form placement tracks (1411,
1412, 1413) for adhesive at the vertebral interfaces.
Upper Bracket Exploded Views (1600, 1700, 1800)
[0159] FIG. 16 (1600), FIG. 1700 (1700), and FIG. 18 (1800)
illustrate exploded views of an exemplary preferred embodiment of
the present invention upper bracket. FIG. 16 (1600) is a top
perspective exploded view of an exemplary upper bracket,
illustrating the sectional nature of the upper bracket in some
preferred embodiments of the invention. As mentioned elsewhere, the
sectional nature of the upper/lower brackets is preferred in many
circumstances, but not necessarily required in some embodiments.
FIG. 17 (1700) is a bottom perspective exploded view of an
exemplary upper bracket (with springs), illustrating the sectional
nature of the upper bracket in some preferred embodiments of the
invention. FIG. 18 (1800) is a bottom perspective assembled view of
an exemplary upper bracket (with springs), illustrating the
sectional nature of the upper bracket in some preferred embodiments
of the invention.
Lower Bracket Assembled Views (1900 2000)
[0160] FIG. 19 (1900) illustrates an assembled view of an exemplary
embodiment of the bottom bracket. As mentioned elsewhere, the
sectional nature of the upper/lower brackets is preferred in many
circumstances, but not necessarily required in some
embodiments.
[0161] As illustrated in FIG. 19 (1900), the lower bracket is the
second element of the spinal implant comprising of two components,
vertebral contact surface and the spring guide track. The vertebral
contact surface will provide a permanent, rigid connection between
the implant and the skeletal structure. The vertebral contact
surface is segmented for ease of installation and providing the
ability to use laparoscopic surgical insertion.
[0162] Each individual segment of the vertebral contact surface
contains a spring guide track. The spring guide track is a groove
that protrudes from the vertebral contact surface that contains the
concave ends of an individual spring. The spring guide track is
flat on the bottom and beveled on either side comprising a
substantially "U" shape extending along the length of each segment
of the vertebral contact surface. At either end of the segmented
vertebral contact surface, there will be an inset overhang that
will function as an arresting force to over-rotation. When
implanted, the articulation of the spring with the spring guide
track will resist axial compression between vertebrae as well as
preventing lateral translation of the implant and inhibiting 360
degree motion at the vertebral level to allow normal support to the
axis between the upper and lower vertebrae at the level of the
spinal implant. The spring guide track (slide guards) can be
altered in length to accommodate individuals with limited ROM at
vertebral levels above and below the spinal implant use.
[0163] The lower bracket vertebral contact surface is otherwise the
same as the upper bracket vertebral contact surface. Located at the
midpoint but on the lateral surface are insertion holes on each
segment. The three segments of the vertebral contact surface
component of the lower bracket are meant to configure together to
comprise the single unit of the lower bracket. The bracket will
extend from the outer edge of the skeletal structure to the
interior, inferior surface of the vertebral body, but generally not
to exceed the diameter of the vertebral body. Either end of the
vertebral contact surface will be angled toward the skeletal
structure so that the surfaces are flush, making a cavity that the
adhesive can fill in to. The under surface of the bracket that
contacts the skeletal surface can be textured/hatched to allow for
maximum surface area to improve adhesion of the implant to the
bone. The adhesive will be injected through the insertion holes on
the lateral surface of each segment.
[0164] Alternatively, the spring and spring guide track component
could be replaced with a series of collapsible cylinders, akin to
shock absorbers. A spiral spring could be substituted for the
concave/convex spring configuration. The spring could be made as a
permanent part of the top bracket and eliminate the bolt and
threaded cylinder attachment. The vertebral contact surface could
be all one piece instead of a three-segmented jigsaw. The U-shape
of the bottom bracket spring guide could be a flat half circle. The
adhesive choice for attachment of the upper and lower bracket could
be substituted for teeth or other type of sharp protuberance that
could be affixed to the vertebrae. The adhesive choice could be
substituted with screws used to secure the upper and lower brackets
to the skeletal structure from the lateral, overlapping portion of
the vertebral contact surface. The spring and spring guide track
component could be replaced with a collapsible honeycomb structure
made of biocompatible material not yet determined, and that would
be secured by other means.
[0165] FIG. 20 (2000) illustrates an exemplary embodiment of the
bottom bracket as installed on a lower spinal vertebrae (2002) and
illustrates how the springs (which are attached to the upper
bracket that is not depicted in this illustration) rest in the
spring guide tracks on the lower bracket. This spring/guide track
configuration provides full ROM for the patient as well as
providing shock absorption for the spinal column.
Upper/Lower Bracket Detail (2100, 2200, 2300, 2400)
[0166] While the upper and lower brackets generally illustrated in
FIG. 8 (0800) can take many forms, detailed illustrations of a
preferred embodiment of these components is illustrated in FIG. 21
(2100), FIG. 22 (2200), FIG. 23 (2300), and FIG. 24 (2400).
[0167] As depicted in FIG. 20 (2000) and FIG. 21 (2100), the spring
component of the upper bracket element of the spinal implant will
permit pivotal movement between the vertebrae and is the key
component to the restoration of ROM in the spinal section. The term
pivotal is intended to describe either or both of a rotation or
twisting motion about the support axis and/or a tilting motion
angularly inclined in any direction relative to the support
axis.
[0168] The spring has a general configuration of an alternating
concave and convex shape. As generally illustrated in FIG. 20
(2000), some preferred invention embodiments will comprise a convex
portion of the spring having a hole to fit into the cylindrical
projection of the upper bracket. The two remaining concave portions
will fit into the tracks of the lower bracket as illustrated in
FIG. 20.
[0169] As illustrated in FIG. 8 (0800), the nut (0822) component of
the upper bracket element of the spinal implant will attach the
spring to the upper bracket. The nut is preferably, but not limited
to, hexagonal in shape with a rounded surface contacting the spring
component. The nut can only be inserted, therefore, in one
direction, so that the rounded end threads onto the cylindrical
threaded projection of the upper bracket in the direction that it
contacts the spring component first. The rounded end of the nut may
in many preferred embodiments correspond with the convex angle of
the spring that it is attaching to the upper bracket. The nut is
preferably fabricated from or coated with materials on threads to
aid in fixation (self-locking) such as a low-friction, wear- and
impact-resistant, biocompatible material such as (for example)
polyethylene, non-absorbable polymers or other biocompatible
polymeric material.
[0170] FIG. 22 (2200) illustrates a side view (from the patient's
front perspective) of an exemplary embodiment of the present
invention and generally illustrates the adhesive injection
holes/ports, three piece preferred sectional design, and tri-spring
interface between the upper and lower brackets.
[0171] FIG. 23 (2300) illustrates a side view (from the patient's
side perspective) of an exemplary embodiment of the present
invention and generally illustrates the adhesive injection
holes/ports, preferred sectional design, and multi-spring interface
between the upper and lower brackets.
[0172] FIG. 24 (2400) illustrates a frontal sectional assembled
view (from the patient's back perspective) of an exemplary
embodiment of the present invention as installed between upper and
lower spinal vertebrae and generally illustrates the spring guide
tracks, preferred sectional design, and multi-spring interface
between the upper and lower brackets.
Fastening Variation--Inverted Acorn Nuts (2500, 2600)
[0173] While a wide variety of methods are available for fastening
springs to the upper bracket, one preferred embodiment is
illustrated in exploded view FIG. 25 (2500) and associated
sectional side view FIG. 26 (2600) wherein inverted acorn nuts and
inset cap screws are used as fasteners to attach the springs to the
upper bracket.
Fastening Variation--Spring Captors (2700, 2800)
[0174] While a wide variety of methods are available for fastening
springs to the upper bracket, another preferred embodiment is
illustrated in exploded view FIG. 27 (2700) and associated
sectional side view FIG. 28 (2800) wherein U-shaped spring brackets
(U-bolt) are used as a retaining means to attach the springs to the
upper bracket.
[0175] The cylindrical projection may be enhanced in the form of a
U-bolt to replace the upper bracket's cylindrical projection
(pseudo screw). The configuration of the U-bolt is exactly as
implied by the term "U". The cylindrical projection would be
lengthened sufficiently to allow the material to be formed into a
"U" configuration, as shown in FIG. 27 (2700).
[0176] Both ends of the "U" would be secured to the upper bracket.
The ends of the "U" could be deformed as described in the rivet
enhancement, or threaded to accept a low profile nut.
[0177] Installation of this type of spring fastener is as follows.
A spring would be placed between the vertical legs of the "U" bolt.
The ends of the "U" would be inserted into respective drilled holes
in the upper bracket sections. The ends would then be secured to
the upper bracket using a mechanical process, (e.g. rivet
operation, low profile nut, etc.)
Fastening Variation--Rivets (2900, 3000)
[0178] While a wide variety of methods are available for fastening
springs to the upper bracket, another preferred embodiment is
illustrated in exploded view FIG. 29 (2900) and associated
sectional side view FIG. 30 (3000) wherein rivets are used as
fasteners to attach the springs to the upper bracket.
[0179] The cylindrical projection described previously can be
enhanced by replacement of the cylindrical projection with a rivet
enhancement. The rivet is a cylindrical piece of surgical
compatible material capable of being intentionally deformed to
secure the spring to the upper bracket The rivet may contain a
cylindrical diameter over which a spring could be placed. One end
of the rivet cylindrical diameter would then be placed in a drilled
hole in the upper bracket. The location of this drilled hole would
be the same location as the existing cylindrical projection
described previously.
[0180] The cylindrical diameter ends of the rivet material would be
secured in a clamping device. This clamping device would exert
sufficient compressive force on the rivet material to cause the
material to deform to the curved portion of the spring and the flat
upper bracket surfaces. The amount of clamping force and resulting
deformation of the rivet material would be controlled to allow the
spring to function as previously described.
Fastening Variation--Acorn Nuts (3100, 3200)
[0181] While a wide variety of methods are available for fastening
springs to the upper bracket, one preferred embodiment is
illustrated in exploded view FIG. 31 (3100) and associated
sectional side view FIG. 32 (3200) wherein enclosed acorn nuts and
inset cap screws are used as fasteners to attach the springs to the
upper bracket.
Non-Co-Planar Disc Structure (3300, 3400)
[0182] The present invention may be implemented using co-planar
upper/lower brackets as illustrated herein in some embodiments.
However, the invention may incorporate non-co-planar (non-planar)
disc structures in which the upper and/or lower bracket is tapered
rather than co-planar, permitting the replacement disc structure to
more fully conform to the requirements of the replaced disc in the
patient.
[0183] This alternate embodiment illustrating non-co-planar
structure is depicted in FIG. 33 (3300) with side sectional view
illustrated in FIG. 34 (3400) more fully illustrating the tapered
nature of the bracket construction. The views in FIG. 33 and FIG.
34 only illustrate one bracket as an example of non-planar
(non-co-planar) structures. Note that the present invention
anticipates any combination of co-planar and non-planar upper
and/or lower brackets.
Vertebral Contact Surface Conditioning (3500, 3600, 3700, 3800)
[0184] The present invention anticipates that the contact surface
between the upper bracket (upper vertebral contact surface) and the
upper spinal vertebrae and/or the surface between the lower bracket
(lower vertebral contact surface) and the lower spinal vertebrae
may be surface conditioned for improved adhesion between the
artificial spinal disc replacement and the surrounding
vertebrae.
[0185] This surface conditioning can take many forms, including
abrasion of the contact surface, chemical treatment, mechanical
polishing, machining, and/or knurling. The present invention does
not limit the scope of this surface conditioning, and one skilled
in the art will be able to delineate a wide variety of surface
conditioning techniques appropriate in this application.
[0186] Examples of exemplary embodiments implementing surface
conditioning are illustrated in FIG. 35 (3500), FIG. 36 (3600),
FIG. 37 (3700), and FIG. 38 (3800). Note, as contrasted in FIG. 35
(3500) and FIG. 36 (3600) as well as FIG. 37 (3700) and FIG. 38
(3800) that the surface conditioning may be either partial (3500,
3700) and/or total (3600, 3800). One skilled in the art will
recognize that more than one type of surface conditioning may be
performed on the upper/lower brackets in some circumstances with no
loss of generality in the scope of the present invention.
Alternative Spring Structures (3900)
[0187] The exemplary embodiments illustrated herein contain an
exemplary spring structure which may be effective in many
applications. However, this particular spring structure is not
limitive as to the range of spring structures which may be
applicable and taught by the present invention. For example, one
alternate spring structure is illustrated in FIG. 39 (3900). While
the spring structure illustrated in FIG. 39 (3900) does not contain
any mounting hole, one skilled in the art will recognize that this
(or other spring structures detailed herein) could be augmented
with a wide variety of mounting holes and/or studs to permit
fastening to the upper bracket. One skilled in the art will
recognize that a wide variety of other spring structures may be
applied to the teachings of the present invention.
[0188] Additionally, note that there is no absolute requirement
within the teachings of the present invention that there is more
than one spring structure within the replacement disc. One skilled
in the art will recognize that the structure illustrated in FIG. 39
(3900) could be fabricated in an arcuate (arc/curved) fashion to
mate within the confines of a spring guide track (having one or
more cavities) that is machined within the lower bracket. This
configuration may include a "wave" style spring structure as
illustrated in FIG. 39 (3900), and may include multiple
peaks/valleys to ensure the proper spring resistance, contact
surface area, and other wear factors required for the application.
While a three-peak example is illustrated in FIG. 39 (3900) (and
this example does not contain any modification to accommodate the
circumferential nature of the spring guide track), one skilled in
the art will recognize that these modifications are easily made to
the structure of FIG. 39 (3900) to accommodate a singular spring
structure if so desired.
[0189] Therefore, the term "spring" as used herein should be given
its broadest applicable definition consistent with the application
to spinal disc replacement. Generally, any material capable of
reflexive deformation (with some degree of recovery) would fit this
definition. As such, any material subject to Hooke's Law would be a
potential candidate for application in the teachings of the present
invention.
Laparoscogic Surgical Installation
[0190] One of the most significant features of the present
invention not available in the prior art is that the present
invention spinal disc replacement may be installed through
laparoscopic surgery. As illustrated in FIG. 3 (0300), the prior
art teaches that a spinal disc replacement requires the "gutting"
of the patient from the front side of the abdomen, cutting of
muscle, and spreading of organs to access the spine from the front
of the patient.
[0191] In contrast, as illustrated in FIG. 4 (0400), the present
invention teaches that the disclosed spinal disc replacement may be
performed laparoscopically from the back side of the patient. By
using special instrumentation and scopes, laparoscopic spinal
surgery requires only a small incision. There are numerous benefits
of this minimally invasive surgery versus surgical incisions made
with traditional fusion surgery. The most significant benefit is a
reduced hospital stay and reduced recuperation time.
System Variations
[0192] No screws will be needed for implantation or stabilization
of this device. However there is a pseudo-screw portion that is
angled and fits into the spring at the same angle. The spring fits
inside the bottom bracket in a glide section, the bottom bracket is
recessed so that the spring fits deeply into the bottom bracket and
is adjustable for ROM. The spring guide is wider than the spring
itself. The connection slot is beveled and is adjustable dependent
on the later and forward motion needed/allowed. The bottom and top
brackets are inclined to meet the vertebral body surface on both
sides. The undersurface of the brackets are textured to allow
maximal attachment surface area to the bone when the residual space
is filled with bone glue. There is a hole in the top and bottom
plate of the brackets to allow for a needle insertion to squirt the
adhesive into the residual space. There are three plates in the
bracket that are jig-sawed (interlocked) together during
implantation to ease the operative procedure.
[0193] The present invention anticipates a wide variety of
variations in the basic theme of construction. The examples
presented previously do not represent the entire scope of possible
usages. They are meant to cite a few of the almost limitless
possibilities.
Generalized Method Embodiment (4000)
[0194] The present invention may incorporate a method of using the
system as described in an application wherein a spinal disc is
replaced within a patient. This method (4000) may be generally
described as follows: [0195] A method of artificial spinal disc
replacement within a patient's spinal column, said method
comprising: [0196] (1) Laparoscopically creating an incision into a
portion of said patient's back at the point of spinal disc
replacement on said spinal column (4001); [0197] (2) Inserting an
upper bracket through said incision, said upper bracket further
comprising springs, spring fasteners, and upper vertebral contact
surface (4002); [0198] (3) Inserting a lower bracket through said
incision, said lower bracket further comprising lower vertebral
contact surface and spring guide track (4003); [0199] (4) Mating
said upper bracket springs into said lower bracket spring guide
track (4004); [0200] (5) Fixing said upper bracket upper vertebral
contact surface to an upper vertebrae within said spinal column
(4005); [0201] (6) Fixing said lower bracket lower vertebral
contact surface to a lower vertebrae within said spinal column
(4006). This method may be augmented and/or modified according to
variations in the artificial spinal disc replacement system as
described above, and specifically anticipates installation of the
spinal disc replacement in sections.
Integrated Upper/Lower Brackets (4100)
[0202] The present invention has generally been described utilizing
a segmented upper/lower bracket assembly as generally illustrated
in FIG. 8 (0810). However, as illustrated in FIG. 41 (4100), the
system may be embodied utilizing unitary upper and/or lower bracket
assemblies. FIG. 41 (4100) illustrates a unitary upper bracket
assembly. The integration of the upper and/or lower brackets may
prove advantageous and convenient in the insertion of the spinal
disc replacement in the patient during surgery.
[0203] The multi-segmented upper/lower brackets illustrated in the
various drawings can be integrated as illustrated in FIG. 41
(4100), and produced and surgically installed as a single piece
structure in all variations previously discussed. This single piece
concept applies to both the upper and lower brackets as described
elsewhere in this document.
Spherical Bearing Interface (4200, 4300, 4400)
[0204] One possible preferred embodiment variation generally
illustrated in FIG. 41 (4100) is the use of fasteners (4101, 4102,
4103) with spherical bearings (4111, 4112, 4113) as detailed in
FIG. 41 (4200), FIG. 43 (4300), and FIG. 44 (4400). The
incorporation of a spherical bearing at each of the threaded
projection locations within the upper bracket segments and/or a
single piece upper bracket allows the threaded projection to adjust
to the spinal wedge angle. As the relationship of the threaded
projection to the lower bracket spring and spring track angle
changes, the spherical bearing allows the threaded projection to
adjust to the needed angle.
[0205] As generally illustrated in FIG. 42 (4200), the spherical
bearing is a truncated sphere (4201) with an internal bore through
the sphere from one flat truncated surface to the opposite flat
truncated surface. The spherical bearing curved surfaces are
encased in the outer housing (4202), which is then mechanically
captured within the upper bracket at the threaded projection
location. The method of mechanically capturing the spherical
bearing can be by mechanical deformation of the interface area of
the spherical bearing to the upper bracket, (e.g., staking), or by
other means well known to those skilled in the art.
[0206] Generally, the installation of the spherical bearing within
the upper bracket is performed during the manufacturing process.
This process requires no mandatory surgical room procedures. As
generally illustrated in FIG. 43 (4300), the installed spherical
bearing allows for the threaded projection/fastener (4203) to be
inserted through the inside diameter of the bearing to secure the
spring as described elsewhere in this document.
[0207] Movement of the spherical bearing with relation to the upper
and lower bracket is generally illustrated in FIG. 44 (4400),
wherein this side assembled view illustrates how the spherical
bearing permits adjustment of the wedge angle between the upper and
lower brackets based on desired patient movement
characteristics.
Wedge Angle Fastener Interface (4500)
[0208] The concept of spherical bearing interface on the upper
bracket can have a variety of embodiments and variations. Each of
these attempts to compensate for the spinal wedge angle alignments
of the patient. The incorporation of wedge alignment features
within the framework of this document are not limited by the
enhancements noted herein.
[0209] One particularly useful preferred embodiment is the use of
an angled threaded projection as generally illustrated in FIG. 45
(4500), wherein the spring fastener (4501) is contained within a
chamfered hole (4502) in the upper bracket. This permits changing
the threaded projection installed angle to an appropriate angle
(optimally, but not limited to the number of degrees necessary) to
allow for a proper spinal wedge angle. The threaded projection
installation and function are similar to those already discussed
within this document, including but not limited to the range of
enhancements discussed herein.
[0210] One skilled in the art will recognize that the chamfered
hole (4502) can be designed with an enlarged and/or elongated hole
to receive the shaft of the spring fastener (4501), permitting some
degree of lateral movement of the spring fastener (4501). This
permissible movement may in some circumstances provide a degree of
ROM similar to that of the spherical bearings discussed previously,
and as such should be considered an alternative to the use of
spherical bearings in some patient applications.
Fusion Block (4600)
[0211] In some circumstances involving special patient conditions
(such as replacement of existing spinal fusions or when ROM is not
wanted at the spinal segment due to injury or spinal anomalies
including disease and instability of the spine) an alternate
embodiment of the present invention is applicable which
incorporates a spinal fusion implant as generally illustrated in
FIG. 46 (4600). This fusion block assembly permits mating of the
upper and lower brackets, but does not provide for rotation or
tilting of the spinal implant bracket sections, thus permitting the
system to be utilized in situations where spinal fusion is the
preferred patient treatment methodology.
[0212] In this preferred fusion block embodiment, fusion blocks
(4601, 4602, 4603) would be installed in place of the springs
described elsewhere in this document. The function of the fusion
blocks (4601, 4602, 4603) would be to supply rigidity and not to
allow ROM as the springs would normally accomplish.
[0213] Fusion blocks (4601, 4602, 4603) would be shaped and
dimensioned to match the spring guide tracks (now referred to as
fusion block guide tracks in this embodiment) and held in place by
threaded projections (referred to as fusion block fasteners) as
were the springs. Materials for the fusion blocks would include any
surgical or biocompatible materials as mentioned previously, as
well as surgical metals and/or polymer compounds.
Bracket Size Modulation (4700, 4800, 4900)
[0214] The upper and/or lower brackets can in some embodiments be
enlarged to fill the maximum surface contact area of the vertebrae,
as generally illustrated in FIG. 47 (4700), FIG. 48 (4800), and
FIG. 49 (4900), wherein the demarcation line (4901) illustrates the
boundary between a conservatively sized bracket (4911) and that of
the enlarged surface contact area contrast (4912). These alternate
preferred embodiments can be contrasted with the
conservatively-sized embodiments illustrated generally by FIG. 8
(0800), in that the demarcation line (4901) delineates the area
difference between the sizes of these two embodiments.
[0215] The miniaturization or enlargement of any of the items
described or detailed herein is anticipated by various embodiments
of the present invention. This miniaturization and/or enlargement
includes implantation of concepts and all surgical methods
resembling, but not limited to, the laparoscopic or minimally
invasive surgical principles or practices known to those skilled in
the art.
[0216] Enlargement of the upper and/or lower bracket as generally
illustrated in FIG. 49 (4900) can be applied to all figures and
diagrams described herein. This enlargement can be applied to all
descriptions of either individual bracket segments or one-piece
(unitary) brackets for the upper and/or lower brackets.
[0217] Enlargement may also be applied to the spring guide tracks,
spring, and/or fusion blocks. The enlargement allows increased
spring travel and modification of spring/fusion block threaded
dimensions, as well as increased surface area for adhesion to
spinal vertebrae. Generally, enlargement of the upper and/or lower
bracket involves increasing the surface area of the bracket beyond
that of the half-circle demarcation line (4901) as illustrated in
FIG. 49 (4912).
Machined Surface Orientation (5000)
[0218] The orientation of the machined surfaces, grooves and
contours of the vertebral contact surfaces of the upper and/or
lower brackets can be lateral in the direction shown in FIG. 50
(5000) with or without the enlargement concept of the vertebral
contact surfaces of the upper and/or lower brackets as generally
illustrated in FIG. 49 (4900).
[0219] One advantage of this configuration is the ability to
perform side insertion/installation of the upper and/or lower
brackets during surgery. In this configuration the side placement
of adhesive insertion holes/ports (5001, 5002, 5003, 5004, 5005,
5006) permits injection of adhesive from the side of the patient
during surgery.
Convex/Concave Mating Surfaces (5100)
[0220] The present invention anticipates a variety of mating
methodologies which may be used to join the upper and/or lower
brackets to the surrounding vertebrae. For example, as generally
illustrated in FIG. 34 (3400), a typical lower bracket can have a
non-coplanar configuration. The present invention also anticipates
that any of the upper and/or lower brackets may incorporate convex
or concave vertebrae mating surfaces to provide greater conformity
to the corresponding concave or convex vertebrae to which the
bracket mates. An example of this in the form of a convex mating
surface is generally illustrated in FIG. 51 (5100) wherein the
convex mating surface (5101) is sized to conform to a corresponding
vertebrae. One skilled in the art will recognize that irregular
mating surface profiles can also be utilized in this application to
provide for more substantial mating contact between the upper/lower
brackets and the corresponding spinal vertebrae.
CONCLUSION
[0221] An artificial spinal disc implant system for intervertebral
disc replacement (0810) is disclosed which is formed from an upper
(0801) and lower (0802) bracket which mate to upper and lower
spinal vertebrae via upper (0831) and lower (0832) vertebral
contact surfaces on the upper (0801) and lower (0802) brackets. The
upper (0801) and lower (0802) brackets are joined together via
springs (0811) connected to the upper bracket (0801) which rest in
spring guide tracks (0812) on the lower bracket. The springs (0811)
are connected to the upper bracket (0801) via the use of spring
fasteners (0821, 0822). The upper (0801) and lower (0802) brackets
may be installed in sections (0851, 0861, 0871, 0852, 0862, 0872)
using laparoscopic surgical techniques and are attached to
upper/lower spinal vertebrae respectively via adhesive means
applied using injection holes/ports (0841, 0842) in the upper
(0801) and lower (0802) brackets respectively.
[0222] The disclosed spinal disc replacement system provides for
pivotal and rotational movement, thereby preserving full
range-of-motion (ROM) in the patient. Alternate embodiments of the
invention permit unitary (one-piece) construction of the
upper/lower brackets, enlarged surface contact areas for the
upper/lower brackets, support for spherical bearings, and
integration of fusion blocks. These modifications to the basic
spinal implant replacement permit varying degrees of motion as
required by the patient as well as a variety of options for
insertion of the device via a variety of surgical techniques well
known in the art.
* * * * *