US20070003598A1

US20070003598A1 - Osteogenic implants for soft tissue

Info

Publication number: US20070003598A1
Application number: US11/517,694
Authority: US
Inventors: Hai Trieu
Original assignee: Warsaw Orthopedic Inc
Current assignee: Warsaw Orthopedic Inc
Priority date: 2003-08-06
Filing date: 2006-09-08
Publication date: 2007-01-04
Also published as: AU2004263123B2; US8920828B2; US20070128575A1; AU2004263123A1; CN100496621C; JP2007501075A; CN1852743A; US20070122446A1; CA2534983A1; US7169405B2; WO2005014071A1; EP1658103A1; US9061064B2; US20050031666A1

Abstract

An osteogenic implant includes a degradation agent in solid form and an osteogenerative agent in solid form. The osteogenic implant is configured to release the degradation agent prior to releasing the osteogenerative agent.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. application Ser. No. 10/634,798, entitled “METHODS AND DEVICES FOR THE TREATMENT OF INTERVERTEBRAL DISCS,” filed Aug. 6, 2003, and naming inventor Hai H. Trieu, which is incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

This disclosure, in general, relates to osteogenic implants, and in particular, to osteogenic implants for treating spinal ailments

BACKGROUND

In human anatomy, the spine is a generally flexible column that can withstand tensile and compressive loads. The spine also allows bending motion and provides a place of attachment for keels, muscles, and ligaments. Generally, the spine is divided into four sections: the cervical spine, the thoracic or dorsal spine, the lumbar spine, and the pelvic spine. The pelvic spine generally includes the sacrum and the coccyx. The sections of the spine are made up of individual bones called vertebrae. Three joints reside between each set of two vertebrae: a larger intervertebral disc between the two vertebral bodies and two zygapophyseal joints or facet joints located posteriolaterally relative to the vertebral bodies and between opposing articular processes.
The intervertebral discs generally function as shock absorbers and as joints. Further, the intervertebral discs can absorb the compressive and tensile loads to which the spinal column can be subjected. At the same time, the intervertebral discs can allow adjacent vertebral bodies to move relative to each other, particularly during bending or flexure of the spine. Thus, the intervertebral discs are under constant muscular and gravitational pressure and generally, the intervertebral discs are the first parts of the lumbar spine to show signs of deterioration.
The zygapophyseal joints permit movement in the vertical direction, while limiting rotational motion of two adjoining vertebrae. In addition, capsular ligaments surround the zygapophyseal joints, discouraging excess extension and torsion. In addition to intervertebral disc degradation, zygapophyseal joint degeneration is also common because the zygapophyseal joints are in almost constant motion with the spine. In fact, zygapophyseal joint degeneration and disc degeneration frequently occur together. Generally, although one can be the primary problem while the other is a secondary problem resulting from the altered mechanics of the spine, by the time surgical options are considered, both zygapophyseal joint degeneration and disc degeneration typically have occurred. For example, the altered mechanics of the zygapophyseal joints or the intervertebral disc can cause spinal stenosis, degenerative spondylolisthesis, and degenerative scoliosis.
Furthermore, acute strenuous events, such as whiplash or overextension, can damage capsular ligaments. Such damage to capsular ligaments if untreated can lead to degradation of the zygapophyseal joint or of the intervertebral disc.
In particular, deterioration can be manifested as a herniated disc. Weakness in an annulus fibrosis can result in a bulging of the nucleus pulposus or a herniation of the nucleus pulposus through the annulus fibrosis. Ultimately, weakness of the annulus fibrosis can result in a tear, permitting the nucleus pulposus to leak from the intervertebral space. Loss of the nucleus pulposus or a bulging of the nucleus pulposus can lead to pinching of nerves, causing pain and damage to vertebrae. In addition, aging can lead to a reduction in the hydration of the nucleus pulposus. Such a loss in hydration can also result in pinching of nerves.
A traditional option for treating a patient includes replacement of the intervertebral disc or the zygapophyseal joint with an implant. Another traditional option includes fusing adjacent vertebra using fasteners, such as traditional screws or rods. However, such traditional methods are typically implemented with invasive surgical procedures. In particular, some traditional surgical procedures access the spine through the abdominal cavity, introducing risk to major organs and often leaving large scars.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure may be better understood, and its numerous features and advantages made apparent to those skilled in the art by referencing the accompanying drawings.
FIG. 1 includes a lateral view of a portion of a vertebral column.
FIG. 2 includes a lateral view of a pair of adjacent vertebrae.
FIG. 3 includes a top plan view of a vertebra.
FIG. 4 includes a cross section view of an intervertebral disc.
FIG. 5 includes a cross section view of a zygapophyseal joint.
FIG. 6 includes an illustration of an exemplary osteogenic implant.
FIG. 7 includes an illustration of exemplary microspheres.
FIG. 8 includes a cross-sectional view illustration of an exemplary osteogenic implant.
FIG. 9 and FIG. 10 include illustrations of an exemplary osteogenic implant.
FIG. 11, FIG. 12, FIG. 13, and FIG. 14 include profile illustrations of exemplary osteogenic implants.
FIG. 15 includes an illustration of an exemplary medical kit.
FIG. 16 and FIG. 17 include illustrations of an exemplary intervertebral space under treatment.
FIG. 18 and FIG. 19 include lateral-view illustrations of an exemplary intervertebral space under treatment.
FIG. 20 includes an illustration of an exemplary zygapophyseal joint under treatment.
FIG. 21 includes a block flow diagram of an exemplary method of forming an osteogenic implant.
FIG. 22, FIG. 23, and FIG. 24 include illustrations of exemplary agent release profiles.
The use of the same reference symbols in different drawings indicates similar or identical items.

DESCRIPTION OF THE DRAWINGS

In a particular embodiment, an osteogenic implant includes a degradation agent and an osteogenerative agent. In an exemplary embodiment, the osteogenic implant is configured to release at least a portion of the degradation agent prior to releasing at least a portion of the osteogenerative agent. The degradation agent can be a nucleolytic agent, such as chymopapain or chondroitinase ABC. In an example, the osteogenerative agent can be an osteoconductive agent or an osteoinductive agent. In a particular example, the osteogenerative agent is an osteoinductive agent, such as a growth factor.
In an embodiment, an osteogenic implant includes a degradation agent in solid form and an osteogenerative agent in solid form. The osteogenic implant is configured to release the degradation agent prior to releasing the osteogenerative agent.
In another exemplary embodiment, an osteogenic implant includes a first polymer matrix including a degradation agent and a second polymer matrix including an osteogenerative agent. The first polymer matrix is configured to release at least a portion of the degradation agent prior to time at which the second polymer matrix is configured to release the osteogenerative agent.
In a further exemplary embodiment, a medical kit includes an osteogenic implant including a degradation agent in solid form and an osteogenerative agent in solid form. The osteogenic implant is configured to release the degradation agent prior to releasing the osteogenerative agent. The medical kit also includes a tool configured to locate the osteogenic implant proximate to a vertebral structure.
In an additional exemplary embodiment, a method of forming an osteogenic implant includes incorporating a degradation agent into a first polymer matrix and incorporating an osteogenerative agent into a second polymer matrix.
In a further exemplary embodiment, a method of treating a patient includes inserting an osteogenic implant into a soft tissue proximate to an osteal structure. The osteogenic implant includes a degradation agent in solid form and an osteogenerative agent in solid form. The osteogenic implant is configured to release the degradation agent prior to releasing the osteogenerative agent.
Description of Relevant Anatomy
Referring initially to FIG. 1, a portion of a vertebral column, designated 100, is shown. As depicted, the vertebral column 100 includes a lumbar region 102, a sacral region 104, and a coccygeal region 106. The vertebral column 100 also includes a cervical region and a thoracic region. For clarity and ease of discussion, the cervical region and the thoracic region are not illustrated.
As illustrated in FIG. 1, the lumbar region 102 includes a first lumbar vertebra 108, a second lumbar vertebra 110, a third lumbar vertebra 112, a fourth lumbar vertebra 114, and a fifth lumbar vertebra 116. The sacral region 104 includes a sacrum 118. Further, the coccygeal region 106 includes a coccyx 120.
As depicted in FIG. 1, a first intervertebral lumbar disc 122 is disposed between the first lumbar vertebra 108 and the second lumbar vertebra 110. A second intervertebral lumbar disc 124 is disposed between the second lumbar vertebra 110 and the third lumbar vertebra 112. A third intervertebral lumbar disc 126 is disposed between the third lumbar vertebra 112 and the fourth lumbar vertebra 114. Further, a fourth intervertebral lumbar disc 128 is disposed between the fourth lumbar vertebra 114 and the fifth lumbar vertebra 116. Additionally, a fifth intervertebral lumbar disc 130 is disposed between the fifth lumbar vertebra 116 and the sacrum 118.
In a particular embodiment, if one of the intervertebral lumbar discs 122, 124, 126, 128, 130 is diseased, degenerated, or damaged or if one of the zygapophyseal joints is diseased, degenerated or damaged, that disc or joint can be at least partially treated with an osteogenic implant according to one or more of the embodiments described herein. In a particular embodiment, an osteogenic implant can be inserted into the intervertebral lumbar disc 122, 124, 126, 128, 130 or a zygapophyseal joint.
FIG. 2 depicts a detailed lateral view of two adjacent vertebrae, e.g., two of the lumbar vertebrae 108, 110, 112, 114, 116 illustrated in FIG. 1. FIG. 2 illustrates a superior vertebra 200 and an inferior vertebra 202. As illustrated, each vertebra 200, 202 includes a vertebral body 204, a superior articular process 206, a transverse process 208, a spinous process 210 and an inferior articular process 212. FIG. 2 further depicts an intervertebral disc 214 between the superior vertebra 200 and the inferior vertebra 202. A zygapophyseal joint 216 is located between the inferior articular process 212 of the superior vertebra 200 and the superior articular process 206 of the inferior vertebra 202. As described in greater detail below, an osteogenic implant according to one or more of the embodiments described herein can be installed within or in proximity to the intervertebral disc 214 between the superior vertebra 200 and the inferior vertebra 202 or within or in proximity to the zygapophyseal joint 216.
Referring to FIG. 3, a vertebra, e.g., the inferior vertebra 202 (FIG. 2), is illustrated. As shown, the vertebral body 204 of the inferior vertebra 202 includes a cortical rim 302 composed of cortical bone. Also, the vertebral body 204 includes cancellous bone 304 within the cortical rim 302. The cortical rim 302 is often referred to as the apophyseal rim or apophyseal ring. Further, the cancellous bone 304 is generally softer than the cortical bone of the cortical rim 302.
As illustrated in FIG. 3, the inferior vertebra 202 further includes a first pedicle 306, a second pedicle 308, a first lamina 310, and a second lamina 312. Further, a vertebral foramen 314 is established within the inferior vertebra 202. A spinal cord 316 passes through the vertebral foramen 314. Moreover, a first nerve root 318 and a second nerve root 320 extend from the spinal cord 316.
The vertebrae that make up the vertebral column have slightly different appearances as they range from the cervical region to the lumbar region of the vertebral column. However, all of the vertebrae, except the first and second cervical vertebrae, have the same basic structures, e.g., those structures described above in conjunction with FIG. 2 and FIG. 3. The first and second cervical vertebrae are structurally different than the rest of the vertebrae in order to support a skull.
Referring now to FIG. 4, an intervertebral disc is shown and is generally designated 400. The intervertebral disc 400 is made up of two components: an annulus fibrosis 402 and a nucleus pulposus 404. The annulus fibrosis 402 is the outer portion of the intervertebral disc 400, and the annulus fibrosis 402 includes a plurality of lamellae 406. The lamellae 406 are layers of collagen and proteins. Each lamella 406 includes fibers that slant at 30-degree angles, and the fibers of each lamella 406 run in a direction opposite the adjacent layers. Accordingly, the annulus fibrosis 402 is a structure that is exceptionally strong, yet extremely flexible.
The nucleus pulposus 404 is an inner gel material that is surrounded by the annulus fibrosis 402. It makes up about forty percent (40%) of the intervertebral disc 400 by weight. Moreover, the nucleus pulposus 404 can be considered a ball-like gel that is contained within the lamellae 406. The nucleus pulposus 404 includes loose collagen fibers, water, and proteins. The water content of the nucleus pulposus 404 is about ninety percent (90%) by weight at birth and decreases to about seventy percent by weight (70%) by the fifth decade.
Injury or aging of the annulus fibrosis 402 can allow the nucleus pulposus 404 to be squeezed through the annulus fibers either partially, causing the disc to bulge, or completely, allowing disc material to escape the intervertebral disc 400. The bulging disc or nucleus material can compress the nerves or spinal cord, causing pain. Accordingly, the nucleus pulposus 404 can be treated with an osteogenic implant to treat ailments associated with the intervertebral disc 400.
FIG. 5 includes a cross-sectional view of the spine illustrating a portion of a superior vertebra 504 and a portion of an inferior vertebra 502. The inferior vertebra 502 includes superior articular processes 506 and 508 and the superior vertebra 504 includes inferior articular processes 510 and 512. Between the superior articular process 506 and the inferior articular process 510 is a zygapophyseal joint or facet 514 and between the superior articular process 508 and the inferior articular process 512 is a zygapophyseal joint or facet 516.
When damaged or degraded, the zygapophyseal joints 514 and 516 can be treated. For example, an osteogenic implant can be inserted into or in proximity to the zygapophyseal joints 514 and 516. In particular, such an osteogenic implant can be configured to fuse the inferior articular process (506 or 508) to the superior articular process (510 or 512).
Description of Agents
In an exemplary embodiment, a device to be implanted at least partially in the nucleus pulposus of an intervertebral disc or in a zygapophyseal joint can include at least one agent in solid or semi-solid form. The agent can generally affect a condition of the nucleus pulposus or affect bone growth. For example, the agent can decrease the hydration level of the nucleus pulposus or can cause a degeneration of the nucleus pulposus that leads to a reduction in hydration level, to a reduction in pressure, or to a reduction in size of the nucleus pulposus within the intervertebral disc. An agent causing a degeneration of the disc or reduction in hydration level is herein termed a “degradation agent.” In another example, an agent (e.g., an osteogenerative agent) can affect bone growth in proximity to the intervertebral disc or the zygapophyseal joint. For example, an osteogenerative agent can be an osteoinductive agent, an osteoconductive agent, or any combination thereof.
An exemplary degradation agent can reduce hydration levels in the nucleus pulposus or can degrade the nucleus pulposus, resulting in a reduction in hydration level or in pressure within the intervertebral disc. For example, the degradation agent can be a nucleolytic agent that acts on portions of the nucleus pulposus. In an example, the nucleolytic agent is proteolytic, breaking down proteins.
An exemplary nucleolytic agent includes a chemonucleolysis agent, such as chymopapain, collagenase, chondroitinase, keratanase, human proteolytic enzymes, papaya proteinase, or any combination thereof. An exemplary chondroitinase can include chondroitinase ABC, chondroitinase AC, chondroitinase ACII, chondroitinase ACIII, chondroitinase B, chondroitinase C, or the like, or any combination thereof. In another example, a keratanase can include endo-β-galactosidase derived from Escherichia freundii, endo-β-galactosidase derived from Pseudomonas sp. IFO-13309 strain, endo-β-galactosidase produced by Pseudomonas reptilivora, endo-β-N-acetylglucosaminidase derived from Bacillus sp. Ks36, endo-β-N-acetylglucosaminidase derived from Bacillus circulans KsT202, or the like, or any combination thereof. In a particular example, the degradation agent includes chymopapain. In another example, the degradation agent includes chondroitinase ABC.
An osteogenerative agent, for example, can encourage the formation of new bone (“osteogenesis”), such as through inducing bone growth (“osteoinductivity”) or by providing a structure onto which bone can grow (“osteoconductivity”). Generally, osteoconductivity refers to structures supporting the attachment of new osteoblasts and osteoprogenitor cells. As such, the agent can form an interconnected structure through which new cells can migrate and new vessels can form. Osteoinductivity typically refers to the ability of the agent or a surface or a portion thereof to induce nondifferentiated stem cells or osteoprogenitor cells to differentiate into osteoblasts.
In an example, an osteoconductive agent can provide a favorable scaffolding for vascular ingress, cellular infiltration and attachment, cartilage formation, calcified tissue deposition, or any combination thereof. An exemplary osteoconductive agent can include collagen; a calcium phosphate, such as hydroxyapatite, tricalcium phosphate, or fluorapatite; demineralized bone matrix; or any combination thereof.
In another example, an osteoinductive agent can include bone morphogenetic proteins (BMP, e.g., rhBMP-2); demineralized bone matrix; transforming growth factors (TGF, e.g., TGF-β); osteoblast cells, growth and differentiation factor (GDF), LIM mineralized protein (LMP), platelet derived growth factor (PDGF), insulin-like growth factor (ILGF), fibroblast growth factor (FGF), platelet derived growth factor (PDGF), members of the hedgehog family of proteins, iriterleukins (Ils), colony stimulating factors (CSF), cartilage derived growth factors (CDGF), cartilage derived morphogenic proteins (CDMP), or any combination thereof. In a further example, an osteoinductive agent can include HMG-CoA reductase inhibitors, such as a member of the statin family, such as lovastatin, simvastatin, pravastatin, fluvastatin, atorvastatin, cerivastatin, mevastatin, pharmaceutically acceptable salts esters or lactones thereof, or any combination thereof. With regard to lovastatin, the substance can be either the acid form or the lactone form or a combination of both. In a particular example, the osteoinductive agent includes a growth factor. In addition, osteoconductive and osteoinductive properties can be provided by bone marrow, blood plasma, or morselized bone of the patient, or other commercially available materials.
In addition, the implantable device can include an anti-inflammatory agent. An exemplary anti-inflammatory agent can include a soluble tumor necrosis factor α-receptor, a pegylated soluble tumor necrosis factor α-receptor, a monoclonal antibody, a polyclonal antibody, an antibody fragment, a COX-2 inhibitor, a metalloprotease inhibitor, a glutamate antagonist, a glial cell derived neurotrophic factor, a B2 receptor antagonist, a substance P receptor (NK1) antagonist, a downstream regulatory element antagonistic modulator (DREAM), iNOS, an inhibitor of tetrodotoxin (TTX)-resistant Na+-channel receptor subtypes PN3 and SNS2, an inhibitor of interleukin, a TNF binding protein, a dominant-negative TNF variant, Nanobodies™, a kinase inhibitor, or any combination thereof. Another exemplary anti-inflammatory agent can include Adalimumab, Infliximab, Etanercept, Pegsunercept (PEG sTNF-R1), Onercept, Kineret®, sTNF-R1, CDP-870, CDP-571, CNI-1493, RDP58, ISIS 104838, 1→3-β-D-glucan, Lenercept, PEG-sTNFRII Fc Mutein, D2E7, Afelimomab, AMG 108, 6-methoxy-2-napthylacetic acid or betamethasone, capsaiein, civanide, TNFRc, ISIS2302 and GI 129471, integrin antagonist, alpha-4 beta-7 integrin antagonist, cell adhesion inhibitor, interferon gamma antagonist, CTLA4-Ig agonist/antagonist (BMS-188667), CD40 ligand antagonist, Humanized anti-IL-6 mAb (MRA, Tocilizumab, Chugai), HMGB-1 mAb (Critical Therapeutics Inc.), anti-IL2R antibody (daclizumab, basilicimab), ABX (anti IL-8 antibody), recombinant human IL-10, HuMax IL-15 (anti-IL 15 antibody), or any combination thereof.
In addition, other agents can be incorporated, such as an antibiotic, an analgesic, an anesthetic, a radio-contrast agent, or any combination thereof. For example, a pain medication can be incorporated in a matrix material in which another agent is incorporated or in a separate matrix material. An exemplary pain medication includes codeine, propoxyphene, hydrocodone, oxycodone, or any combination thereof. In a further example, an antiseptic agent can be incorporated within a matrix material. For example, the antiseptic agent can include an antibiotic agent. In an additional example, a radio-contrast agent can be incorporated into a reservoir, such as an agent responsive to x-rays.
Each of the agents or a combination of agents can be maintained in solid or semi-solid form. For example, solid forms can include powder, granules, microspheres, miniature rods, or embedded in a matrix or binder material, or any combination thereof. In an example, fluids or water from surrounding tissues can be absorbed by the device and placed in contact with an agent in solid form prior to release. Further, a stabilizer or a preservative can be included with the agent to prolong activity of the agent.
In particular, one or more agents can be incorporated into a polymeric matrix, such as a hydrogel, a non-bioresorbable polymer, a bioresorbable polymer, a natural polymer, or a recombinant polymer. An exemplary hydrogel can include polyacrylamide (PAAM), poly-N-isopropylacrylamine (PNIPAM), polyvinyl methylether (PVM), polyvinyl alcohol (PVA), polyethyl hydroxyethyl cellulose, poly (2-ethyl) oxazoline, polyethyleneoxide (PEO), polyethylglycol (PEG), polyacrylacid (PAA), polyacrylonitrile (PAN), polyvinylacrylate (PVA), polyvinylpyrrolidone (PVP), or any combination thereof. A non-bioresorbable polymer can include a hydrogel and can include polyurethane, silicone, polymethylmethacrylate (PMMA), polyethylene, poly vinyl alcohol, poly vinyl pyrrolidon, poly(2-hydroxy ethyl methacrylate), poly(acrylic acid), ethylene vinyl acetate, poly(ethylene glycol), poly(methacrylic acid), polyacrylamide, or any combination thereof. An exemplary bioresorbable polymer can include polylactide (PLA), polyglycolide (PGA), poly(lactide-co-glycolide) (PLGA), polyanhydride, polyorthoester, or any combination thereof. An exemplary natural polymer or a recombinant polymer can include a polysaccharide, collagen, silk, elastin, keratin, albumin, fibrin, starch, chitosans, gelatin, alginates, dextrans, or any combination thereof. Other exemplary polymers include poly(alpha-hydroxy acids), conjugates of poly(alpha-hydroxy acids), polyaspirins, polyphosphagenes, PVA-g-PLGA, PEGT-PBT copolymer (polyactive), PEO-PPO-PEO (pluronics), PEO-PPO-PAA copolymers, PLGA-PEO-PLGA, polyphosphoesters, polyester-anhydrides, polyamino acids, polyurethane-esters, polyphosphazines, polycaprolactones, polytrimethylene carbonates, polydioxanones, polyamide-esters, polyketals, polyacetals, glycosaminoglycans, hyaluronic acid, hyaluronic acid esters, polyethylene-vinyl acetates, silicones, polyurethanes, polypropylene fumarates, polydesaminotyrosine carbonates, polydesaminotyrosine arylates, polydesaminotyrosine ester carbonates, polydesamnotyrosine ester arylates, polyethylene oxides, polyorthocarbonates, polycarbonates, or copolymers or physical blends thereof or combinations thereof.
In a particular example, a hydrogel can hydrate to release an agent. In a further example, a non-bioresorbable polymer can be configured to break apart or disintegrate as a result of hydration, mechanical stress, or vibration. In another example, a bioresorbable polymer can dissolve or can be absorbed, releasing an agent incorporated therein. In a further example, a natural polymer can act as a hydrogel, a bioresorbable polymer, or a non-bioresorbable polymer and release an agent as a result of hydration, dissolution, or disintegration.
Description of a Device
In an exemplary embodiment illustrated in FIG. 6, an osteogenic implant 600 includes a degradation agent and an osteogenerative agent. In an example, the degradation agent can be included in a first matrix material 602 and the osteogenerative agent can be included in a second matrix material 604. In particular, the osteogenic implant 600 is configured to release at least a portion of the degradation agent prior to releasing at least a portion of the osteogenerative agent. For simplicity, releasing an agent is used herein to mean releasing at least a portion of the agent unless explicitly stated otherwise. For example, the osteogenic implant 600 can release the degradation agent prior to releasing the osteogenerative agent. Alternatively, the osteogenic implant 600 can be configured to release substantially all of the degradation agent prior to releasing the osteogenerative agent.
For example, FIG. 22, FIG. 23, and FIG. 24 include illustrations of exemplary agent release profiles. As illustrated in FIG. 22, the degradation agent release profile 2202 can reach a peak concentration prior to the osteogenerative agent release profile 2204. As depicted, the release profiles 2202 and 2204 can overlap. Further, the degradation agent release profile can begin close to the time 2206 of implanting or can be delayed in time from the time 2206. As illustrated in FIG. 23, the osteogenerative agent release profile 2304 can begin after the degradation agent release profile 2302 subsides. For example, the beginning of the osteogenerative agent release profile 2304 can be delayed from the cessation of the degradation agent release profile 2302 by a period of time 2308. Further, the release profiles can be different, for example, having different peak concentrations and length of release. As illustrated in FIG. 24, the degradation release profile 2402 can have a higher peak and quicker release than the osteogenerative agent release profile 2404. In particular, the osteogenerative agent release profile 2404 can provide a lower dose for a longer period of time.
Returning to FIG. 6, the first matrix material 602 and the second matrix material 604 can be relatively located in the osteogenic implant 600 in positions that, in operation, results in the release of the degradation agent prior to the osteogenerative agent. For example, the first matrix material 602 can be located around the second matrix material 604. In another example, the first matrix material 602 can be located closer to an opening of the osteogenic implant 600 than the second matrix material 604, resulting in dissolution or hydration of the first matrix material 602 prior to the second matrix material 604.
In another exemplary embodiment, the first matrix material 602 can have a composition that results in faster release of the degradation agent when in operation and the second matrix material 604 can have a composition that results in slow release or delayed release of the osteogenerative agent. In a particular example, the first matrix material 602 can include a first polymer material and the second matrix material 604 can include a second polymer material. For example, the first matrix material 602 can include starch or another material that degrades relatively quickly and the second matrix material 604 can include a hydrogel or degradable polymer, such as PEO or PGA, that hydrates or degrades to release an agent relatively slower. In addition, one or both of the matrix materials 602 and 604 can include radio-contrast media.
In a particular example, the matrix material (602 or 604) can include a biocompatible injectable polymer or polymer precursor. In an example, the polymer can be a hydrogel, a soft gel, an elastic material, or any combination thereof that can immobilize the agent or agents. In particular, the matrix material (602 or 604) can include a polymer precursor that can react in vivo to form a polymer. For example, the matrix material (602 or 604) can react to form a hydrogel, a soft gel, an elastomer, a rigid material, or any combination thereof. In a particular example, the matrix material (602 or 604) can react to form a rigid load-bearing component. In an example, the matrix material (602 or 604) can form a fusion cage or other structure. In a further example, the polymer formed from the injectable material can be degradable or resorbable in vivo.
Further, the matrix materials 602 and 604 can be incorporated into more than one osteogenic implant. For example, the matrix materials 602 and 604 can be incorporated into separate osteogenic implants. Alternatively, the matrix materials 602 and 604 can be incorporated together in more than one osteogenic implant to be inserted.
In addition, the osteogenic implant 600 can include a third agent, such as an antibiotic, an analgesic, an anesthetic, a radio-contrast agent, an anti-inflammatory agent, or any combination thereof. The third agent can be incorporated in one or both of the first matrix material 602 or the second matrix material 604. For example, the first matrix material 602 can include an anti-inflammatory agent. In another example, the second matrix material 604 can include an anesthetic agent. In a further example, the second matrix material 604 can include a radio-contrast agent. As such, dispersion of the radio-contrast agent can be detected by a radiographic technique and can indicate the onset of release of the osteogenerative agent.
FIG. 7 includes an exemplary osteogenic implant 700 including sets of microspheres (704 and 706) in a solution 702. For example, a set of microspheres 704 can include a degradation agent and a set of microspheres 706 can include an osteogenerative agent.
In an example, the solution 702 can be a biocompatible fluid, gel, paste, slurry, or any combination thereof. In an example, the solution 702 is configured to prevent release of the agents from the microspheres prior to implant. For example, the solution 702 can be a saline solution, an alcohol solution, a glycerol solution, an oil-based solution, a polymer, or any combination thereof. In particular, the solution 702 can include an injectable polymer that is configured to react in vivo to form a hydrogel, a soft gel, an elastomer, a rigid polymer, or any combination thereof. The solution 702 also can include a radio-contrast agent. In another example, the solution 702 can be a gel, such as a high viscosity gel. Alternatively, the sets of microspheres (704 and 706) can be included in separate solutions.
The sets of microspheres (704 or 706) can be incorporated into the solution 702 during manufacture or prior to implantation. For example, the sets of microspheres (704 or 706) can be incorporated in the solution 702 at the time of manufacture. In another example, the sets of microspheres (704 or 706) can be mixed with the solution prior to surgery or implantation.
In particular, the sets of microspheres (704 or 706) can be configured to release agents at different times or at different rates. For example, the set of microspheres 704 can be configured to release a degradation agent at a fast rate or following implantation. The set of microspheres 706 can be configured to release an osteogenerative agent at a slower rate or at a delayed time. For example the set of microspheres 706 can include a coating that results in delayed release of the osteogenerative agent. Alternatively, the composition of the set of microspheres 706 can be configured to hydrate or dissolve at a slower rate than the set of microspheres 704.
The microspheres in the set of microspheres (704 or 706) can have an average diameter in a range of approximately 1.0 micron to approximately 4.0 mm. For example, the average diameter can be approximately 10 microns to approximately 2.0 mm, such as approximately 100 microns to 1.0 mm.
In general, the osteogenic implant 700 can be implanted using a syringe. The syringe can be inserted through the epidermis and into a soft tissue region proximate to an osteal structure, such as an intervertebral space. In an example, the location of the tip of the syringe can be determined by radioscope. In a particular example, the tip of the syringe can be located in an intervertebral space, such as within a nucleus pulposus. The solution and the sets of microspheres (704 and 706) can be released into the soft tissue, such as the nucleus pulposus. As a result, the sets of microspheres (704 and 706) can hydrate or dissolve at different rates, resulting in release of the respective agents at different rates or at different times. In addition, one or more of the solution 702, and the sets of microspheres (704 and 706) can include radio-contrast agents. Alternatively, the degradation and osteogenerative agents can be incorporated in powder from into different polymers or polymer precursors that result in release of the agents at different rates once implanted in vivo.
In another exemplary embodiment illustrated in FIG. 8, the osteogenic implant 800 can be configured in a multilayer structure. For example, the osteogenic implant 800 can be configured as a sphere, a cylinder, or a polygon. In particular, a first matrix material 802 can be coated over a second matrix material 804. Alternatively, additional layers of matrix material can be included. For example, the first matrix material 802 can form a coating layer over a core layer formed of the second matrix material 804. The first matrix material 802 can include a degradation agent and the second matrix material 804 can include an osteogenerative agent.
Once implanted, the osteogenic implant 800, for example, can dissolve or hydrate. In an example, the first matrix material 802 can hydrate, dissolve, or disintegrate to release the degradation agent prior to the second matrix material 804 hydrating, dissolving, or disintegrating to release the osteogenerative agent. In a further exemplary embodiment, layers can be located outside of the first matrix material 802, intermediate to the first and second matrix materials 802 and 804, or underlying the second matrix material 804. For example, an additional coating external to the first matrix material 802 can delay exposure of the first matrix material 802 and provide protection for the first matrix material 802 during transport or implanting. A layer located between the first and second matrix materials (802 and 804) can delay exposure of the second matrix material 804 until after the first matrix material 802 hydrates, dissolves, or disintegrates. Further, a layer located internal to and surrounded by the second matrix material 804 can alter its dose and rate of release based on a change in surface area, volume, or the ratio thereof of the second matrix material 804.
While the cross-sectional view illustrated in FIG. 8 depicts a cylinder or a sphere, the osteogenic implant 800 can be a sheet material or a polygonal material. In particular, the osteogenic implant 800 can be configured based on the desired functionality of the osteogenic implant 800 and techniques for implanting such an osteogenic implant 800.
In a particular embodiment, the osteogenic implant can form a cylinder. Such a form is conducive to implantation using a cannula/trocar assembly, and can be directed through connective tissue. For example, a soft tissue can be pierced by a cannula/trocar assembly. The trocar can be removed and the osteogenic implant inserted into a lumen of the cannula. A stylet can be used to push the osteogenic implant through the lumen of the cannula and into the soft tissue.
For example, FIG. 9 includes an illustration of an exemplary osteogenic implant 900, which includes a coating 902 and an opening 908. The coating 902 can include a polymer, ceramic, metallic material, or any combination thereof In a particular example, the coating 902 can include an osteoconductive material.
In another example, the coating can include a fluid impermeable material to limit access to materials surrounded by the coating 902. Materials incorporating agents can be surrounded by the coating 902 and can be accessible through the opening 908. For example, a first material 904 can be located closer to the opening 908 than a second material 906. As such, the first material 904 can be exposed to fluids of soft tissue in which the osteogenic implant 900 is to be implanted before the second material 906 can be exposed.
In a particular example, the first material 904 can include a degradation agent and the second material 906 can include an osteogenerative agent. As such, the first material 904 can hydrate, dissolve, or disintegrate prior to the second material 906, releasing the degradation agent prior to releasing the osteogenerative agent.
Alternatively, the osteogenic implant 900 can include more than one opening 908 and can be formed into additional shapes. For example, the osteogenic implant can form a sphere, a polygon, a cone, a cylinder, or any combination thereof.
In an additional embodiment, FIG. 10 includes an illustration of an osteogenic implant 1000 that includes a coating 1002 and more than one opening 1010 through the coating 1002. In addition, the osteogenic implant 1000 includes materials 1004, 1006, and 1008. In particular, the material 1004 is located closer to an opening 1010 than the material 1006, and the material 1006 is located closer to an opening 1010 than the material 1008.
In an exemplary embodiment, the material 1004 can be free of a degradation agent or an osteogenerative agent. In an example, the material 1004 can hydrate, dissolve, or disintegrate to expose the material 1006. The material 1006 can include a degradation agent and the material 1008 can include an osteogenerative agent. As a result, the material 1006 can hydrate, dissolve, or disintegrate prior to the material 1008, resulting in the release of the degradation agent prior to the release of the osteogenerative agent.
In another exemplary embodiment, the material 1004 can include a degradation agent, the material 1006 can be free of a degradation agent or an osteogenerative agent, and the material 1008 can include an osteogenerative agent. As a result, the material 1004 can hydrate, dissolve, or disintegrate prior to the material 1006, resulting in the release of the degradation agent. The material 1006 can hydrate, dissolve, or disintegrate prior to the material 1008, resulting in a delay in the release of the osteogenerative agent.
In a further exemplary embodiment, the material 1004 can include a degradation agent, the material 1006 can including both a degradation agent and an osteogenerative agent, and the material 1008 can include an osteogenerative agent. As a result, the material 1004 can hydrate, dissolve, or disintegrate to release the degradation agent. Subsequently, the material 1006 can hydrate, dissolve, or disintegrate to release both the degradation agent and the osteogenerative agent, and finally, the material 1008 can hydrate, dissolve, or disintegrate to release additional osteogenerative agent. Alternatively, the device can be configured with a gradient of agent concentration. Further, while the materials 1004, 1006, and 1008 are discussed in relation to degradation agents and osteogenerative agents, the materials 1004, 1006, and 1008 also can include other agents, such as an anti-inflammatory agent, an antibiotic, an analgesic, an anesthetic, a radio-contrast agent, or any combination thereof.
In addition, the osteogenic implant can include surface configurations to assist with implanting. In particular, the osteogenic implant can include terminal ends that are configured to engage a tool or move through tissue and can include surface features that engage tissue. For example, a cylindrical osteogenic implant can have a tapered terminal end configured to more easily move through soft tissue. In an example illustrated in FIG. 11, the terminal end 1102 of an osteogenic implant 1100 can have a round shape. In another example illustrated in FIG. 12, the terminal end 1202 of an osteogenic implant 1200 can have a cone shape, a pyramidal shape, or a blade shape.
In another exemplary embodiment, the osteogenic implant can have a terminal end configured to engage a tool, for example, during implanting. For example, FIG. 13 includes an illustration of an osteogenic implant 1300 including a tapered end 1302 and an engagement end 1304. The engagement end 1304 can be configured to engage a tool, such as a stylet. As illustrated, the engagement end 1304 can have a rounded indentation to engage a rounded end of a stylet. In another example, the engagement end 1304 can include a conical, a cross-shaped, a pyramidal, a triangular, a rectangular, or a cylindrical indentation, or any combination thereof.
In addition, the external surface of the osteogenic implant can include serrations, threads, barbs, or any combination thereof. As illustrated in FIG. 14, an osteogenic implant 1400 can include a tapered terminal end 1402 and a shaped surface 1404. For example, the shaped surface 1404 can form threads. Such threads can be used to further motivate the osteogenic implant 1400 through soft tissue or to control insertion depth. In another example, serrations or barbs can be used to secure the osteogenic implant within the soft tissue, or can be used to agitate a surface of an osteal structure, such as a vertebral end plate.
Medical Kit
In an exemplary embodiment, the osteogenic implant can be included in a medical kit. For example, FIG. 15 includes an illustration of a medical kit 1500 that includes one or more osteogenic implants 1502. Alternatively or in addition, the medical kit 1500 can include at least one set of microspheres, either in dry form or in solution.
In addition, the medical kit 1500 can include a scalpel 1504 or another tool for making incisions. Further, the medical kit 1500 can include a suture or thread 1506.
Further, the medical kit 1500 can include a tool for implanting the osteogenic implants 1502. For example, the medical kit 1500 can include a cannula 1512 and can include a trocar 1508 or a stylet 1510 to engage the cannula 1512. In a particular example, the osteogenic implants 1502 can be implanted by locating the tip of the cannula 1512 and trocar 1508 at a desired location within a soft tissue. The trocar 1508 can be removed from the cannula 1512 and the osteogenic implants 1502 placed in the lumen of the cannula 1512. The stylet 1510 can be used to motivate the osteogenic implants 1502 through the lumen of the cannula 1512 and into the soft tissue.
In addition, the medical kit 1500 can include a container 1516 with a ceramic material, bone cement, tissue sealant, or any combination thereof and a syringe 1514 for injecting the ceramic material, bone cement, or tissue sealant into the tissue. In particular, when the osteogenic implants 1502 are implanted in a nucleus pulposus through the annulus fibrosis, the syringe 1514 can be used to inject tissue sealant to seal the annulus fibrosis and prevent the nucleus pulposus from herniating.
In addition, the medical kit 1500 can include written instructions 1518 indicating methods of using the various components of the medical kit 1500. The instructions 1518 can direct the use of the osteogenic implant 1502, the assembly of the osteogenic implant 1502, counter-indications for use of such implants, warnings and caveats, or any combination thereof.
In an example, the medical kit 1500 can be included in a single container and sealed. Alternatively, the medical kit 1500 can be an assembly of various containers including various components of the medical kit 1500.
Osteogenic Implant Implantation
The osteogenic implant can be inserted into the nucleus pulposus of an intervertebral disc of a patient or into a zygapophyseal joint of a patient. For example, the osteogenic implant can be implanted as a whole within the nucleus pulposus or within the zygapophyseal joint. In another example, the osteogenic implant can be place in proximity to the zygapophyseal joint.
FIG. 16 and FIG. 17 include illustrations of an osteogenic implant 1604 implanted within the nucleus pulposus 1602 of an intervertebral disc 1600. The osteogenic implant 1604 can be inserted through a passage 1606 in the annulus fibrosis 1608 of the intervertebral disc 1600. In an example, the passage 1606 is formed and a cannula or an instrument having a lumen therethrough can be used to guide the osteogenic implant 1604 through the passage 1606. Once the osteogenic implant 1604 is inserted into the nucleus pulposus 1602, the passage 1606 in the annulus fibrosis 1608 can be sealed using a tissue sealant, scaffold plug, or any combination thereof. In a particular example, the tissue sealant or scaffold plug includes regenerative agents, such as growth factors. A similar method can be used to insert an osteogenic implant into a zygapophyseal joint.
Once the osteogenic implant 1604 is located within the nucleus pulposus, matrices within the osteogenic implant 1604 can hydrate, dissolve, or disintegrate to release agents. For example, a matrix material can hydrate to release a degradation agent. As a result, a treatment region 1710 of the nucleus pulposus 1602 can degrade. Subsequently, another matrix material of the osteogenic implant 1604 can release an osteogenerative agent to initiate bone growth.
In an alternative embodiment illustrated in FIG. 18, the osteogenic implant 1808 can be inserted into the nucleus pulposus of an intervertebral disc 1810 through one of a superior vertebra 1802 or an inferior vertebra 1806. As illustrated in FIG. 18, the osteogenic implant 1808 can be inserted through the vertebral body and the end plate of the superior vertebra 1802. For example, an access 1814 can be drilled through the vertebral body and the end plate of the superior vertebra 1802. The osteogenic implant 1808 can be guided through the access 1814 into a nucleus pulposus of the intervertebral disc 1810. The access 1814 can be sealed with a ceramic material, bone cement, tissue sealant, or any combination thereof.
In an exemplary embodiment, one or more materials of the osteogenic implant 1808 can hydrate, dissolve, or disintegrate to release one or more agents. For example, a matrix material can release a degradation agent, resulting in the degradation of the nucleus pulposus within a treatment region 1804. The treatment region 1804, for example, can include a portion of the nucleus pulposus and the cartilaginous end plate of the superior and inferior vertebrae 1802 and 1806.
In addition, a matrix material of the osteogenic implant 1808 can hydrate, dissolve, or disintegrate to release an osteogenerative agent. The osteogenerative agent can influence growth of bone between the superior and inferior vertebrae 1802 and 1806. For example, the osteogenerative agent can encourage fusion of the two vertebrae 1802 and 1806 through the formation of an osteal bridge structure 1912, as illustrated in FIG. 19.
In a further exemplary embodiment illustrated in FIG. 20, an osteogenic implant 2012 is inserted into a zygapophyseal joint or facet joint 2010 through an articular process, such as a superior articular process 2006 of an inferior vertebra 2002. Alternatively, the osteogenic implant 2012 can be inserted through the inferior articular process 2008 of the superior vertebra 2004. In an exemplary embodiment, the osteogenic implant 2012 is inserted through an access 2014 drilled into an articular process. The osteogenic implant 2012 can engage one or both of the articular processes 2006 or 2008. Alternatively, the osteogenic implant 2012 can be positioned within the zygapophyseal joint to not engage the articular processes 2006 or 2008. The access 2014 can be sealed with a ceramic material, bone cement, tissue sealant, or any combination thereof.
While the embodiments illustrated in FIG. 16, FIG. 17, FIG. 18, and FIG. 20 illustrate a single osteogenic implant, one or more osteogenic implants can be implanted in an intervertebral space or a joint. For example, two, three or more osteogenic implants can be placed within an intervertebral space.
In a particular embodiment, osteogenic implants can be inserted into the intervertebral disc and the two articular processes associated with two adjacent vertebrae. As such, the implanted devices can influence bone growth to fuse the two adjacent vertebrae together at three locations: between the vertebral bodies, between the left articular processes, and between the right articular processes.
Patient Treatment Using an Implantable Device
Typically, the embodiments of the osteogenic implant described above can be used to treat conditions associated with an intervertebral disc. For example, a patient can have undergone a prior discectomy or can have experienced a herniated disc. In another example, a scan of the patient, such as a computed tomography (CT) scan or a magnetic resonance imaging (MRI) scan, can indicate a problem in a particular intervertebral disc. In such a case, a device can be implanted in the patient.
In an exemplary embodiment, a healthcare provider can monitor the osteogenic implant, such as through using radiographic techniques. For example, the osteogenic implant can include radio-contrast agents within one or more matrix materials of the osteogenic implant. Each of the radio-contrast agents in the matrix materials can be release with other agents with in the matrix material and can degrade or be removed from the area through biological or diffusion processes. Alternatively, a radio-contrast agent can be injected separately and can degrade or diffuse. In a particular example, a matrix material including an osteogenerative agent can include a radio-contrast agent that is released when the matrix material is hydrated, dissolved, or disintegrated. As such, a healthcare provider can observe release of the osteogenerative agent based on the coincidental release of the radio-contrast agent. In another example, different radio-contrast agents can be included in different matrix materials. Each radio-contrast agent can be separately detectable to indicate release of different agents.
Based on the data received from radiographic techniques, the healthcare provider can adjust treatment of the patient, such as injecting an additional agent. For example, once osteogeneration has been initiated, the healthcare provider can inject or implant additional osteogenerative material. For example, the healthcare provider can inject an osteoconductive gel or additional cellular material, such as stem cells. In particular, a surgeon can inject stem cells that respond to the osteogenerative agent being release from the implanted device as indicated by the coincidental release of a radio-contrast agent.
In addition, the device can be used in conjunction with other devices such as mechanical supports, such as an intervertebral body spacer, an interspinous spacer, a fusion cage, pedicle screw and rod systems (e.g., a percutaneous rod device), a screw, a rigid polymer formed from an injectable polymer precursor, an interior plate,or any combination thereof. For example, the device can be used in conjunction with a SEXTANT® system available from Medtronic Sofamor Danek.
Formation of an Osteogenic Implant
In an exemplary embodiment, the osteogenic implant can be formed in accordance with an exemplary method 2100 illustrated in FIG. 21. For example, a degradation agent can be incorporated in a first matrix material, as illustrated at 2102. In a particular example, a degradation agent, such as chymopapain or chondroitinase ABC, can be incorporated into the first matrix material. The first matrix material can be a polymeric material, such as a hydrogel or a bioresorbable material. In particular, the first matrix material can release the degradation agent through a hydration mechanism or a dissolving mechanism.
In addition, an osteogenerative agent can be incorporated in a second matrix material, as illustrated at 2104. In a particular example, an osteogenerative agent, such as an osteoconductive or an osteoinductive agent, can be incorporated into the second matrix material. In particular, an osteoinductive agent can include a growth factor, such as bone morphogenic protein. The second matrix material can be a polymeric material, such as a hydrogel or a bioresorbable material. In particular, the second matrix material can release the osteogenerative agent through a hydration mechanism or a dissolving mechanism.
Further, the first and second matrix materials can be incorporated into an osteogenic implant, as illustrated at 2106. For example, the osteogenic implant can be formed through molding the first and second matrix materials. In an example, the second matrix material can be molded into a sphere and the first matrix material can be molded around the second matrix material as a coating. In another example, the first and second matrix materials can be formed into separate sets of microspheres and incorporated into a solution. In a further example, the first and second matrix materials can be inserted into a hollow device. In an additional example, the first and second matrix materials can be formed as separate cylinders, placed in a row, and coated with an exterior coating material.
In addition, other agents, such as an anti-inflammatory agent, an antibiotic, an analgesic, an anesthetic, a radio-contrast agent, or any combination thereof, can be incorporated into the first or second matrix materials. In another example, the other agent can be included in a third matrix material. One or more additional matrix materials can be used to form the osteogenic implant.
Conclusion
With the implanted device described above, osteal structures can be fused or bone growth can be effected. In particular, such devices can be implanted using laparoscopic techniques. Such devices can further reduce the likelihood that a more invasive disc replacement implant will be used.
The above-disclosed subject matter is to be considered illustrative, and not restrictive, and the appended claims are intended to cover all such modifications, enhancements, and other embodiments that fall within the true scope of the present invention. For example, it is noted that the components in the exemplary embodiments described herein as having a particular function or as being located in a particular location are illustrative and it is noted that such components can perform additional functions or be located in different configurations. Thus, to the maximum extent allowed by law, the scope of the present invention is to be determined by the broadest permissible interpretation of the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.

Claims

1. An osteogenic implant comprising:

a degradation agent in solid form; and

an osteogenerative agent in solid form;

wherein the osteogenic implant is configured to release the degradation agent prior to releasing the osteogenerative agent.

2. The osteogenic implant of claim 1, wherein the osteogenerative agent is an osteoconductive agent.

3. The osteogenic implant of claim 1, wherein the osteogenerative agent is an osteoinductive agent.

4. (canceled)

5. The osteogenic implant of claim 1, wherein the degradation agent includes a nucleolytic agent.

6.-7. (canceled)

8. The osteogenic implant of claim 1, wherein the degradation agent is included in a microsphere.

9. The osteogenic implant of claim 8, wherein the microsphere is included in a solution.

10. (canceled)

11. The osteogenic implant of claim 1, wherein the degradation agent is included in an outer layer of the osteogenic implant surrounding a core layer including the osteogenerative agent.

12. The osteogenic implant of claim 1, further including an outer layer having an opening, wherein the degradation agent is included in a first region within the outer layer and the osteogenerative agent is included in a second region within the outer layer.

13. The osteogenic implant of claim 12, wherein the first region is closer to the opening than the second region.

14. The osteogenic implant of claim 1, wherein the degradation agent is included in a polymeric matrix.

15.-16. (canceled)

17. The osteogenic implant of claim 1, wherein the osteogenerative agent is included in a polymer matrix.

18.-19. (canceled)

20. The osteogenic implant of claim 1, further comprising an anesthetic agent or an analgesic agent.

21. The osteogenic implant of claim 20, wherein the osteogenic implant is configured to release at least a portion of the anesthetic agent or the analgesic agent in conjunction with the degradation agent.

22.-24. (canceled)

25. The osteogenic implant of claim 1, wherein the osteogenic implant includes an elongated form and a tapered end.

26. An osteogenic implant comprising:

a first polymer matrix including a degradation agent; and

a second polymer matrix including an osteogenerative agent;

wherein the first polymer matrix is configured to release at least a portion of the degradation agent prior to time at which the second polymer matrix is configured to release the osteogenerative agent.

27. The osteogenic implant of claim 26, wherein the osteogenerative agent is an osteoconductive agent.

28. The osteogenic implant of claim 26, wherein the osteogenerative agent is an osteoinductive agent.

29.-32. (canceled)

33. The osteogenic implant of claim 26, wherein the first polymeric matrix includes a hydrogel.

34. The osteogenic implant of claim 26, wherein the first polymeric matrix includes a bioresorbable polymer.

35.-36. (canceled)

37. The osteogenic implant of claim 26, further comprising an anesthetic agent.

38. The osteogenic implant of claim 37, wherein the osteogenic implant is configured to release at least a portion of the anesthetic agent in conjunction with the degradation agent.

39.-40. (canceled)

41. A medical kit comprising:

an osteogenic implant including:

a degradation agent in solid form; and

an osteogenerative agent in solid form;

wherein the osteogenic implant is configured to release the degradation agent prior to releasing the osteogenerative agent; and

a tool configured to locate the osteogenic implant proximate to a vertebral structure.

42. The medical kit of claim 41, wherein the tool includes a lumen and wherein the osteogenic implant is configured to fit within the lumen.

43.-68. (canceled)