US20140277467A1 - Prosthetic Spinal Disk Nucleus - Google Patents

Abstract

This specification describes technologies relating to an intervertebral disc prosthesis used to strengthen and stabilize the spine. Implementations of the technology described herein comprise a surgical device that is implanted through a small surgical incision into a portion of a human intervertebral disc, various support tools used to insert such a surgical device, and a method by which the device is used to strengthen and stabilize the spine.

Description

TECHNICAL FIELD
• This invention relates to surgically implanted devices, and more particularly to intervertebral disc prostheses.
BACKGROUND
• The human vertebral column is a vital part of the human physiology that houses and protects the spinal cord, and provides structural support for the body. In a typical human, the vertebral column is made up of twenty-four articulating vertebrae and nine fused vertebrae, and is generally divided into several regions, including the cervical, thoracic, sacral, and coccygeal regions.
• While variations exist between each vertebra depending on its location and region, vertebrae generally consist of a body, pedicles, a lamina, a spinous process, transverse processes, facet joints, and a spinal canal, each of which play a pivotal role in providing the overall supportive and protective functionality of the vertebral column. Of these features, the vertebral body is of particular importance in providing support. The vertebral body is the largest portion of the vertebra, provides an attachment point of intervertebral discs, protects the spinal cord, and bears the majority of the load of the vertebra.
• Each vertebra is separated from an adjacent vertebra by an intervertebral disc, a cartilaginous joint that acts as a ligament to hold the vertebrae together. A disc consists of an outer annulus fibrosus which surrounds the inner nucleus pulposus. The annulus fibrosus consists of several layers of fibrocartilage which contain the nucleus pulposus and distribute pressure evenly across the disc. The nucleus pulposus contains loose fibers suspended in a mucoprotein gel. The nucleus of the disc acts as a shock absorber, absorbing the impact of the body's daily activities and keeping the two vertebrae separated.
• While the interverbral disc protects adjacent vertebral bodies from impact or contact, various disorders may comprise the structure of the discs and negatively impact their functionality. For example, due to age, the nucleus pulposus may dehydrate and deform, or the annulus fibrosus may weaken and become more prone to tearing. Discs may also be damaged through trauma, resulting in undesirable bulging or loss of nucleus pulposus through a fissure. These disc disorders may diminish a disc's ability to absorb shock and transfer loads, or may cause adjacent vertebrae to contact, possibly resulting in acute or chronic pain for those suffering from these disorders.
• To restore the functionality of a damaged or degenerated intervertebral disc, a common approach includes performing a discectomy to remove compromised material from within the intervertebral disc, and subsequently implanting a prosthesis in the void space created during the discectomy. The primary intention of these procedures is to ameliorate back pain by interrupting the vicious cycle that arises from abnormal spinal biomechanics and spinal instability, and by disrupting the cascade of reactive and degenerative processes of the bony and soft tissue. A secondary benefit is to limit the collateral damage to the spinal soft tissue envelope that is typical of traditional open spinal surgery and minimally invasive spinal surgery, thus diminishing postoperative pain and allowing earlier recovery.
• So far, the methods and instrumentation required to achieve these goals have not been adequately developed or commercially available due to several deficiencies. First, existing methods and instrumentation have largely focused on total disc replacement, where the entirety of an intervertebral disc is removed and is replaced with a hinge-based prosthesis or a single-chambered disc-shaped inflatable structure. In these implementations, no attempt is made to preserve the annular fibrosis, which may be healthy despite degradation to the nucleus pulposus. Second, there is no existing method for the removal and replacement of intervertebral material, and the preservation of the annular fibrosis, that is performed entirely percutaneously.
• Ideally, the treatment of intervertebral discs would involve a minimally invasive procedure, such that the discectomy and implantation process minimizes the disturbance of healthy surrounding tissue. Likewise, the tools and implants used during this process should be capable of minimally invasive deployment and operation. The implant should provide sufficient structural support to restore the functionality of an intervertebral disc, and should ideally preserve a significant degree of articulation freedom between vertebrae. The implant should also be resilient against sudden physical shocks and others external forces, such that it can withstand stresses seen during normal patient movement.
SUMMARY
• This specification describes technologies relating to an intervertebral disc prosthesis used to strengthen and stabilize the spine. Implementations of the technology described herein comprise a surgical device that is implanted through a small surgical incision into a portion of a human intervertebral disc, various support tools used to insert such a surgical device, and a method by which the device is used to strengthen and stabilize the spine.
• Various implementations of the present invention provide benefits that are desirable for surgical applications. The implantation of the device is minimally invasive, as it can be inserted and deployed within the body through a single small incision. As such, the implantation process results in minimal damage to healthy surrounding structures. The various tools used to deploy the device may also be deployed and operated through the same single incision, likewise minimizing collateral damage to healthy tissue. The device provides structural support to restore the functionality of an intervertebral disc, and also preserves a significant degree of articulation freedom between vertebrae. The device is also resilient against sudden physical shocks and others external forces, such that it can withstand stresses seen during normal patient movement.
• One example embodiment of the present invention includes an implantable prosthetic device comprising: an inner chamber; an outer chamber fluidly isolated from the inner chamber; and a sealing valve in fluid communication with the inner chamber and the outer chamber, the sealing valve comprising a first sealing mechanism, a second sealing mechanism, and a stopper element. When the sealing valve is in an open state, the first sealing mechanism allows the inflow of a first material into the inner chamber and the second sealing mechanism allows the inflow of a second material into the outer chamber. When the sealing valve is in a closed state, the first sealing mechanism prevents outflow of the first material from within the inner chamber and the second sealing mechanism prevents outflow of the second material from within the outer chamber. A force applied the stopper causes the sealing valve to enter the open state; and the release of the force causes the sealing valve to enter the closed state.
• One or more embodiments of the present invention include one or more of the following features: The first material comprises an inert gas. The second material comprises a silicone polymer. The silicone polymer is curable. The second material comprises an imaging contrast agent. An inflation device comprising a first channel and a second channel fluidly isolated from the first channel; wherein the inflation device is adapted to apply the force to the stopper, position the first channel in fluid communication with the inner chamber, position the second channel in fluid communication with the outer chamber, and simultaneously transfer the first material from the first channel to inner chamber and transfer the second material from the second channel to the outer chamber. The prosthetic device is collapsible. Inflating the inner chamber or the outer chamber with a material causes the prosthetic device to expand. The implantable device comprises a memory material, wherein the memory material expands the device to a pre-determined shape. The stylus and implantable device are adapted to fit into a surgical cannula. The device is adapted for use as an intervertebral disc prosthesis. The device is implanted to fit adjacent a first vertebra against an upper surface and a second vertebra against a lower surface, such that the first vertebra is separated from the second vertebra.
• In yet another embodiment of the present invention, a method of implanting a prosthetic device comprises the steps of: penetrating the annular fibrosus; removing the nucleus pulposus; implanting an inflatable device within the annular fibrosus, wherein the inflatable device comprises an inner chamber, an outer chamber fluidly isolated from the inner chamber; and a sealing valve in fluid communication with the inner chamber and the outer chamber, the sealing valve comprising a first sealing mechanism, a second sealing mechanism, and a stopper element. When the sealing valve is in an open state, the first sealing mechanism allows the inflow of a first material into the inner chamber and the second sealing mechanism allows the inflow of a second material into the outer chamber. When the sealing valve is in a closed state, the first sealing mechanism prevents outflow of the first material from within the inner chamber and the second sealing mechanism prevents outflow of the second material from within the outer chamber. A force applied to the stopper causes the sealing valve to enter the open state; and the release of the force causes the sealing valve to enter the closed state.
• In yet another implementation of the present invention an inflatable implantable device comprises an inflatable inner chamber and an inflatable outer chamber, wherein the outer chamber further comprises memory shape material adjacent the outer periphery capable of deforming from a first delivery shape, to a second, deployed shape; and an inflation valve in fluid communication with the inner and outer chamber and configured to receive and retain a first medium in the first chamber and a second medium in the second chamber. The inflation valve is configured to simultaneously inflate the first chamber with a first medium and the second outer chamber with a second medium.
• In still a further implementation of the present invention, a method of providing cured silicon to the body comprises: implanting an inflatable containment element in the body; injecting a flowable, curable silicone into the containment vessel; and curing the injected silicone using either a curing agent or UV light. The implanted inflatable containment element is a balloon comprising an inner chamber fluidly isolated from an outer chamber, wherein the silicon is injected into at least one of the inner or the outer chambers.
• In an additional implementation of the present invention, a method of providing cured silicone to the body comprises: creating a body cavity; injecting a flowable curable silicone into the body cavity; and curing the injected silicone using either a curing agent or UV light. The body cavity is made within a vertebral disc by removing the nucleus pulposus from within the annulus fibrosus; and wherein the silicone is injected within the annulus fibrosus. The silicone is injected freely into the annulus fibrosus or into a balloon within the annulus fibrosus.
• In an further still embodiment of the present invention; a system for implanting an inflatable prosthetic vertebral nucleus comprises: an access and delivery cannula having an inner diameter, a nucleotomy tool for removal of the nucleus pulposus from a vertebral disc, wherein the nucleotomy tool is sized to fit within the inner diameter of the access and delivery cannula; a delivery and inflation stylus for delivering an inflatable prosthetic implant, wherein the stylus is sized to fit within the inner diameter of the access and delivery cannula; and an inflatable prosthetic disc implant comprising a first and second chamber, wherein the first and second chamber are fluidly isolated from one another, and the prosthetic disc implant is sized to be delivered through the access cannula by the delivery and inflation stylus to a position within the vertebral disc in an uninflated state.
• And in an additional implementation of the invention a method for implanting an inflatable prosthetic vertebral nucleus, comprises: penetrating the annulus fibrosus and accessing the nucleus pulposus of an intervertebral disk using an access and delivery cannula; delivering through the access cannula a nucleotome that is configured to allow the removal of the nucleus fibrosis from the intervertebral disc while leaving the annulus fibrosus substantially intact; maneuvering the nucleotome within the intervertebral disc to remove the nucleus pulposus; removing the nucleotome; delivering a folded and deflated prosthetic implant through the access and delivery cannula and through the annulus fibrosus into the void formerly occupied by the nucleus pulposus; inflating the prosthetic implant using an inflation stylus wherein the prosthetic implant is inflated with at least two mediums including a gas and a curable silicon; curing the silicone within the prosthetic implant using a curing agent or UV light; and removing the inflation stylus and the access and delivery cannula.
• In yet another implementation an access cannula for penetrating and accessing the annulus fibrosus of a vertebral disc comprises: a proximal end; a distal end; and an inner diameter sized to deliver one or more instruments or prosthetic devices; wherein the one or more instruments include a nucleotome, a delivery stylus, or an inflatable balloon. The proximal end is attachable to a light source. The inner diameter is sized to fit around one or more access dilators. The cannula further includes a set screw and adhesive set screw assembly.
• The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the invention will be apparent from the description and drawings, and from the claims.
DESCRIPTION OF DRAWINGS
• FIG. 1 is a perspective view of a portion of a human vertebral column.
• FIG. 2 is a cross-sectional view of a human intervertebral disc.
• FIG. 3 is a perspective view of exemplary surgical tools.
• FIG. 4 is a perspective view of an exemplary implant device.
• FIGS. 5A-N illustrate an exemplary method of use including the surgical tools and implant device.
• FIGS. 6A-F are cross-sectional views of exemplary surgical tools.
• FIGS. 7A-B are cross-sectional views of an exemplary tool anchor.
• FIG. 8 is an overhead cross-sectional view of an exemplary implant device.
• FIG. 9 is a side view of an exemplary implant device.
• FIG. 10 is a front view of an exemplary implant device.
• FIGS. 11A-B are detailed cross-sectional views of an exemplary dual-valve structure.
• FIG. 12 is a cross-sectional view of an implant device deployed between vertebrae.
• FIGS. 13A-C illustrate cross-sectional views of a non-symmetrically expanding embodiment of an implant device.
• FIGS. 14A-B are cross-sectional views of alternative embodiments of a fill stylus.
• Like reference symbols in the various drawings indicate like elements.
• FIG. 15 is a cross-sectional view of a spacer element.
• FIG. 16 illustrates an example usage of a spacer element during the insertion of an implant device.
DETAILED DESCRIPTION
• The following description is of one exemplary embodiment of the invention. The description is not to be taken in a limiting sense, but is made for the purpose of illustrating the general principles of the invention. Various inventive features are described below that can each be used independently of one another or in combination with other features.
• Broadly, this disclosure is directed at surgical tools for accessing the nucleus pulposus of an intervertebral disc and surgically implantable intervertebral disc prostheses.
• Exemplary implementations of the present invention comprise various components of a surgical kit for accessing portions of the intervertebral disc, removing or displacing tissue, and delivering and implanting a prosthetic device. The kit in one exemplary embodiment comprises an access and delivery cannula, a nucleotomy tool for removal of the nucleus pulposus, a delivery and inflation stylus for delivering an inflatable prosthetic implant, and an inflatable prosthetic disc implant. An exemplary method of using an implementation of the present invention comprises penetrating the annulus fibrosus and accessing the nucleus pulposus of an intervertebral disk using an access and delivery cannula; delivering through the access cannula a nucleotome that is configured to allow the removal of the nucleus fibrosis from the intervertebral disc while leaving the annulus fibrosus substantially intact; maneuvering the nucleotome within the intervertebral disc to remove the nucleus pulposus; removing the nucleotome; delivering a folded and deflated prosthetic implant through the access and delivery cannula and through the annulus fibrosus into the void formerly occupied by the nucleus pulposus; inflating the prosthetic implant using an inflation stylus wherein the prosthetic implant is inflated with at least two mediums including a gas and a curable silicon; and removing the inflation stylus and the access and delivery cannula.
• Various aspects of the present invention, for example, a surgical tool for removing tissue from the body, such as removing nucleus pulposus from an intervertebral disc are disclosed in U.S. patent application Ser. No. 13/831,355, entitled “Surgical Device”, filed concurrently with this application and incorporated herein by reference in its entirety. Broadly the tool includes an access and delivery cannula through which a nucleotome can be delivered. The nucleotome includes one or more passages to provide irrigation, suction and a flexible agitation tool.
• Other aspects of the present invention, including an example inflatable prosthetic implant are disclosed in U.S. Patent Application Pub. No. US 2010/0256766, entitled Percutaneous Implantable Nuclear Prostheses and filed, Apr. 2, 2010, is incorporated herein by reference in its entirety.
• FIGS. 1 and 2 illustrate a portion of a typical human vertebral column. Avertebral column100 is made up of severalvertebral bodies102,104, and106 separated byintervertebral discs108 and110.Intervertebral disc108 is made up of anannular fibrosis202 surrounding a region ofnucleus pulposus204.
• FIG. 3 illustrates exemplary surgical tools used to access the nucleus pulposus of an intervertebral disc. Tools includeguide sleeve302,guide pin304,obturator306,several dilators308a-d, andouter cannula310.
• FIG. 4 illustrates anexemplary implant device400 andinflation stylus402.Implant device400 may be attached toinflation stylus402.
• FIG. 5 illustrates an exemplary method of use oftools302,304,306,308 and402 to insertimplant device400 through theannulus fibrosis202 ofintervertebral disc108, and deployimplant device400 as an intervertebral disc prostheses.
• Referring toFIG. 5A,guide pin304 is slideably inserted intoguide sleeve302, and guidesleeve302 andguide pin304 are inserted through the skin of a patient in a prone position.Guide sleeve302 andguide pin304 enter the patient's body in an oblique postero-lateral approach. Force is applied to guidesleeve302 andguide pin304 until the leading tip ofguide pin304 piercesannular fibrosis202, creatingaperture502.
• Referring toFIG. 5B,guide pin304 is slideably withdrawn fromguide sleeve302.Guide sleeve302 remains in its inserted position, sustainingaperture502 ofannular fibrosis202.
• Referring toFIG. 5C,obturator306 is slideably inserted intoguide sleeve302, such that the leading tip ofobturator306 extends out ofguide sleeve302, throughannular fibrosis202 andaperture502, and intonucleus pulposus204.
• Referring toFIG. 5D,dilator308 is inserted telescopically aroundguide sleeve302 until its distal end reaches the distal margins of theannulus fibrosis202, wideningaperture502.Several dilators308 of increasingly larger diameters may be telescopically inserted in succession to gradually widenaperture502.
• Referring ofFIG. 5E, whenaperture502 is widened to the desired size,outer cannula310 is telescopically inserted around thedilators308. Similar to the insertion ofdilators308,outer cannula310 is advanced until its distal end reaches the distal margins of theannulus fibrosis202.
• Referring toFIG. 5F, guidesleeve302,obturator306, anddilators308 are slideably withdrawn from withinouter cannula310.Outer cannula310 remains in its inserted position, sustainingaperture502 in a dilated state.
• Referring toFIG. 5G,nucleus pulposus204 is removed throughouter cannula310. Removal may be through a vacuum suction applied toouter cannula310, or through a separate nucleus pulposus removal tool (not shown) that is inserted intoouter cannula310 and operated withinannular fibrosis202.
• Referring toFIG. 5H, afternucleus pulposus204 is removed, avoid504 is created withinannular fibrosis202.
• Referring toFIG. 5I,implant device400 andinflation stylus402 are inserted intoouter cannula310.
• Referring toFIG. 5J, force is applied toinflation stylus402 to pushimplant400 intovoid504.
• Referring toFIG. 5K,implant device400 is filled with a gas or other material passed throughinflation stylus402. This inflatesimplant device400, expanding it in size.
• Referring toFIG. 5L, whenimplant device400 is fully inflated, implant device fills a portion of or the entirety ofvoid504, and directly abuts the inner circumference ofannular fibrosis202.
• Referring toFIG. 5M,inflation stylus402 is detached from400 and withdrawn throughouter cannula310.
• Referring toFIG. 5N,outer cannula310 is withdrawn, leavingimplant device400 positioned withinannular fibrosis202 Annular fibrosis retracts, closingaperture502.
• During this process, the position of each of the tools and implants may be tracked and guided through imaging observation techniques typical in the field of interventional radiology. Imaging modalities may include fluoroscopy, magnetic resonance imaging (MRI), computed tomography (CT), X-ray imaging, positron emission tomography (PET), or other medical imaging technique. During this process, imaging may be conducted alongside the implantation procedure, such that progress may be tracked in real-time.
• As this process is conducted predominantly through narrow access channels created byguide sleeve302 andouter cannula310, and may be externally observed through common interventional radiology techniques, this process is minimally invasive to the patient. This process may be carried out under local anesthesia and under conscious sedation, thus avoiding the risk of general anesthetics. Alternatively, these techniques may also be utilized in conjunction with more invasive techniques, and need not be limited in application.
• Moreover, as no portion ofannular fibrosis202 is excised from the body during this process, this technique is minimally traumatic to the patient. In particular, healing of the annular fibrosis is rapid compared to techniques requiring the excision of annular fibrosis tissue, and the preservation of the annular fibrosis structure limits the loss of intra-discal pressure, improving a patient's long-term recovery.
• FIG. 6 illustrates in greater detail the various tools described above. Referring toFIG. 6A, guidesleeve302 is generally an axially extending tube of uniform diameter, definingaperture602 on its proximal end andaperture604 on its distal end and achannel606 between.Guide sleeve302 includes anannular shoulder614 at its proximal end.Guide sleeve302 is generally of an ovular cross section, but may alternatively have a circular, ovular, obround, square, polygonal, or irregular cross-section.
• Guide pin304 is shaped to correspond tochannel606, and may be slideably inserted intoguide sleeve302.Guide pin304 includes a sharpenedtip608, abody portion610, and atail portion612.Tip608 is pointed to allow for insertion into theannular fibrosis202, as may be of a conical, beveled, or other such shape.Tail612 is generally reduced in cross-sectional size compared tobody610, such that whenguide pin304 is fully inserted intoguide sleeve302,tail612 passes throughaperture606. In this configuration,guide pin body610 abutsshoulder614, restricting the movement ofguide pin304.
• Guide pin304 may slideably removed from withinguide sleeve302 and replaced withobturator306, as illustrated inFIG. 6B.Obturator306 is generally similar in shape and dimensions to guidepin304, but has a dulledtip616.Obturator306 likewise includes atail portion620 that is generally reduced in cross-sectional size compared to abody portion618 and adapted to pass throughaperture602.
• Dilator308 may be telescopically inserted around the exterior ofguide sleeve302, as illustrated inFIG. 6C.Dilator308 is generally similar in shape to guidesleeve302, but is wider in diameter to fit snuggly around the exterior surface ofguide sleeve302.Several dilators308 of successively larger cross-sectional diameters may be sequentially inserted to increase the overall diameter of the nested tools. Eachdilator308 includes a shoulder with anaperture632, through which thetail portion620 ofobturator306 may pass.
• When the desired number ofdilators308 have been nested aroundguide sleeve302,outer cannula310 is telescopically inserted around theoutermost dilator308, as illustrated inFIG. 6D.Outer cannula310 is generally similar in shape tocase sleeve302 anddilators308, and is shaped to fit snuggly around the exterior surface of theoutermost dilator308. However,outer cannula310 does not have a shoulder region on its proximal tip. On its distal tip, outer cannula definesaperture622.Aperture622 is obliquely positioned to correspond to an oblique postero-lateral approach into the annular fibrosis, and to allow for guidance of tools in a transverse orientation. Depending on the desired direction of tool guidance, the size and orientation ofaperture622 may be varied. For example, in some embodiments,aperture622 is not obliquely positioned, and is instead positioned along the longitudinal extension ofouter cannula310. In other embodiments,aperture622 is positioned orthogonal to the longitudinal extension of the outer cannula. In some embodiments, the tip ofouter cannula310 may include a slanted redirecting element such as a curved or inclined surface. This surface may be concave to conform to the convex surfaces of an inserted tool or device.
• The user may also place acap634 overdilators308 andouter cannula310 to ensure that unwanted material does not fall untilaperture624.Cap634 is a generally in the shape of an edged annulus with anaperture636.Guide pin tail612 orobturator tail620 may fit throughaperture636, such thatcap634 may be slideably placed or removed from its installed position overouter cannula310 ordilators308.
• Asouter cannula310 does not have a shoulder region,obturator306,guide sleeve302, and the one ormore dilators308 may be separated fromouter cannula310 by liftingtail portion620 ofobturator306, as illustrated inFIG. 6E.
• In this manner, the above tools are used to form a gradually widening aperture into an intervertebral disc and are then removed, leaving anouter cannula310 to maintain the aperture at a desired dilated size and to provide external access for other tools or devices.
• Ahammer624 may be used to position drivetools302,304,306,308, and310 within the patient.Hammer624 includes ahandle626, anannular contact element628, and ahinge element630.Contact element628 is adapted to fit aroundguide pin tail612 orobturator tail620, and may be used to strike a tool in order to drive it deeper into the operating region.Hinge630 allows handle626 to rotate relative to628 such that handle626 may be swung without altering the orientation ofstriking element628.
• Each oftools302,304,306,308, and310 are generally of an ovular cross section, but may alternatively have a circular, ovular, obround, square, polygonal, or irregular cross-section. Generally,tools302,304,306,308, and310 are made of surgically compatible materials, such that they can be safely used in a sterile environment. Some portions oftools302,304,306,308, and310 may be made of a radiopaque material, such that they provide imaging contrast during x-ray or fluoroscopic procedures. Some portions oftools302,304,306,308, and310 may be made of non-ferrous materials, such that they are usable in conjunction with magnetic resonance imaging. Portions oftools302,304,306,308, and310 may be made of paramagnetic or super paramagnetic materials, such that they provide imaging contrast during MRI.
• Tools302,304,306,308, and310 may be anchored to the exterior of the patient to prevent shifting. As illustrated inFIG. 7A,anchor700 is positioned on the exterior of the patient to grip a tool, for instanceouter cannula310. Referring toFIG. 7B, retaining ring includes anannular retaining ring702 shaped encircle the exterior surface of a tool. Retainingring702 includes alower flange704, which may be coated with an adhesive to firmly attachanchor700 to the patient's skin. Anadjustment screw706 is provided to adjustably secure the tool to anchor700. Turning theadjustment screw706 compresses the retainingring702 around the tool, tightly gripping the tool in position. Turning the adjustment screw in the opposite direction releases the tool, allowing eitheranchor700 or the tool to be removed or repositioned. As the nested tools widen in diameter, for instance if several dilators are telescopically inserted one after another,adjustment screw706 may be used to gradually widen retainingring702 to secure each new tool.Adjustment screw706 may be of a captive design, such that it cannot be removed from retainingring702 after becoming fully unscrewed. In some embodiments,adjustment screw706 may be replaced by a pin or a latch. In some embodiments, retainingring702 may be tightened by a ratcheting mechanism or other similar fastener.
• FIG. 8 illustrates an embodiment ofimplant device400 in greater detail. Shown from an overhead cross-sectional view,implant device400 is generally an obround cylinder with two major chambers: a centrally locatedinner chamber802 and annularouter chamber804.Inner chamber802 is distinct fromouter chamber804, such that substances contained in one chamber cannot pass into the other chamber.
• Chambers802 and804 are defined, in part, by outer body layers806 and808,inner body layer810, andsupport bodies812 and814. Outer body layers806 and808 are secured to forwardsupport body814 by acrimp element818, and torear support body812 by acrimp element816Inner body layer810 is secured to forwardsupport body814 by acrimp element822 and torear support body816 by acrimp element820.
• Layers806,808, and810 may be formed of any durable material that is adequately firm, pliable, and resilient, such as silicone or a bio-compatible textile. Each layer should allow for deformation, such that ifchambers802 and804 are inflated, layers806,808, and810 can deform, expanding the outer dimensions ofdevice implant400. Each layer may be made of the same material, or may each be made of a different material in order to provide various benefits. For instance,layer806 made be made of a bio-compatible textile, such that the outermost surface ofimplant device400 is resistant against tears and punctures, whilelayer808 may be made of a different material, such as silicone, to provide a softer, more compliant containment layer forchamber804. In some embodiments,layers806 and808 are affixed along a portion to the entirety of each layer. In some embodiments,layer806 and808 may be fixed together or to other portions ofdevice400 with an adhesive, with thread, or with other such attachment mechanisms.
• Outer body layer806 also includessupport wires824 and826, for example as illustrated inFIGS. 8 and 9.FIG. 9 illustrates a side view ofimplant device400 withsupport wire824 embedded inouter body layer806.Support wires824 and826 are typically of a biocompatible memory metal, such nitinol, such that outer body layers806 and808 may be pressed againstinner body layer810 whenchamber804 is empty (for instance whenimplant device400 is loaded into a delivery cannula), but will expand to a pre-determined shape when released (for instance whenimplant device400 is expelled from a delivery cannula is positioned within an intervertebral disc). Pre-determined shapes may include, for example, a three-dimensional convex shape corresponding to the inner surface of an annular fibrosis.Several notches828 provide seating room forsupport wires824 and826, such that outer body layers806 and808 can seat flush againstinner body layer810. In some embodiments,wires824 and826 are embedded inlayer806. In some embodiments,wires824 and826 are instead positioned on the surface oflayer806 and attached to layer806 by various attaching mechanisms, such as adhesive or thread. In some embodiments,wires824 and826 are attached by passing between each wire repeatedly between the inner and outer surfaces in a stitch-like pattern.
• Generally,support bodies812 and814 are also made of a firm, pliable and resilient materials. Typically,support bodies812 and814 are of a firmer material than that oflayers806,808, and810 in order to provide added structural support forimplant device400. For example,support bodies812 and814 may be made of a stiffer silicone polymer that is more resistant against externally applied forces. However,support bodies812 and814 need not be made of a stiffer material thanlayers806,808, and810, and the stiffness and resilience of these materials may be varied to achieve the desired physical characteristics.
• Inner chamber802 is additionally defined byforward wall844 andrear wall840.Walls844 and840 abutforward support body814 andrear support body812, respectively, creating an air-tight and liquid-tight seal.Walls844 and840 may be secured to each support body in various ways, for example a notched arrangement, as illustrated inFIG. 8.Walls844 and840 may be alternatively or additionally secured using other mechanisms, for example with an adhesive, weld, crimp, or thread.Walls844 and840 may also instead be integral with each support body, such that a securing mechanism is not required.Walls844 and840 are generally of a firm material, such as a dense silicone polymer, such that the general shape ofwalls844 and840 are preserved under the application of external force. However, the materials ofwalls844 and840 may also be varied to achieve a desired stiffness and resilience.
• Whenimplant device400 is positioned within an intervertebral disc,chambers802 and804 may each be inflated with various substances to increase the physical dimensions ofimplant device400 and to provide prosthetic support. Inflation substances may pass from acylindrical fill channel834 intoouter chamber804 throughaperture830. One ormore apertures830 are defined throughforward support member814,inner body layer810, and crimp822, and provide fluid communication betweenfill channel834 andouter chamber804.
• Inflation substance may pass fromfill channel834 intoinner chamber802 throughvalve832. As illustrated inFIG. 8,valve832 may be of a self-sealing design, such that pressure from withininner chamber802seals valve832. In some embodiments,valve832 may be integral withwall844. Alternativelyvalve832 may be a separate element, as illustrated inFIG. 10. In these embodiments,valve832 may be secured towall844 in various ways, such as through an adhesive, weld, or thread. When secured with thread, one ormore thread holes1002 may be positioned along the faces ofwall844 andvalve832, such that a securingthread1004 may be used to tiewall844 and832 together.Valve832 may be made of various materials, such as a rubber or silicone polymer.
• Inflation ofimplant device400 is regulated by dual-valve structure836 positioned withinfill channel834. Dual-valve structure836 is illustrated in greater detail inFIG. 11. Dual-valve structure836 includes anannular stopper1102 attached tospring element1104 and filltube1106.Fill tube1106 extends fromfill channel834 to achannel838 defined withinrear support member812, and has twoapertures1108 and1110. In its sealed state, as illustrated inFIG. 11A,spring elements1004force stopper1110 away fromwall844, sealingaperture830 andvalve832. In this state, no substance may enter orexit chambers802 and804. In some embodiments, there may be one ormore spring elements1004. In some embodiments,multiple spring elements1004 may be arranged to evenly apply force tostopper1110.
• Dual-valve structure may be opened by pressingstopper1102 against the force ofspring elements1004, as illustrated inFIG. 11B. In this open state,stopper110 is pushed towardswall844, unblockingaperture830. In addition, asstopper110 is pushed towardwall844, filltube1106 is pushed, movingfill tube1106 along throughvalve832 andchannel838 untilaperture1110 passes out ofvalve832 and intoinner chamber802. Thus, in this open state,valve832 is opened and substances may pass fromfill channel834 intoinner chamber802 throughapertures1108 and1110.
• A suitably dimensionedfill stylus402 may be used to simultaneously open dual-valve structure836 and inflateimplant device400. The leading tip of an example embodiment offill stylus402 is illustrated in greater detail inFIG. 11B. Fillstylus402 is generally tubular and includes afill needle1116 positioned withinchannel1114, and anannular plunger1118 affixed to fillneedle1116. Fillneedle1116 is tubular withapertures1120 and1122, and is otherwise air-tight and liquid-tight. As such, substances contained withinfill needle1116 remain separated from substances contained withinchannel1114. Fillstylus402 also includesexternal threads1124 corresponding tointernal threads1126 offill channel834. Thus, fillstylus402 may be attached toimplant device400 by screwingfill stylus402 intofill channel834. Asfill stylus402 is screwed in,plunger1118 advances, pushingstopper1102 againstwall844 and revealingaperture830 tochannel1114. In addition, fill needle aperture124 abuts dual-valve structure aperture1108, providing gaseous or fluid communication betweenfill needle1116 andinner chamber802. Substances fromchannel1114 and fillneedle1116 may then be passed intochamber804 andchamber802, respectively, inflatingimplant device400. This may be accomplished, for example, using a motorized pump system, a manually operated pump, or a syringe mechanism. Pumping of each substance withinfill stylus402 may be controlled simultaneously or individually, such that the filling of eachchamber802 and804 may be simultaneously or individually regulated.
• Afterimplant device400 has been inflated, fill stylus1112 is unscrewed, returning dual-valve structure836 to its closed state and sealingchambers802 and804. In some embodiments, dual-valve structure836 also includes one or more bosses or protuberances on the surface ofstopper1102, corresponding to apertures830. Whenstopper1102 sides from an open position to a closed position, the bosses may engage withaperture830, securingstopper1102.
• As the above demonstrates,chambers802 and804 may be simultaneously inflated, each with different materials. As illustrated inFIG. 12, this dual-chamber arrangement allowsimplant device400 to fully support twoadjacent vertebrae102 and104 while preserving a desirable degree of joint flexibility and shock protection. For instance, in some implementationsouter chamber804 may be inflated with an in situ curable silicone polymer whileinner chamber802 may be inflated with an inert gas. In such an arrangement, the silicone polymer hardens upon curing, allowingouter chamber804 to act as firm, largely incompressible support structure between the two vertebrae. The gas-filledinner chamber802 remains comparatively compressible, allowingimplant device400 to sustain sudden shocks and loads typical of active joint motion. Such an arrangement also preserves joint flexibility between two adjacent vertebrae, allowing for joint articulation.
• A number of embodiments of the invention have been described. Nevertheless, it will be understood that various modifications may be made without departing from the spirit and scope of the invention. Accordingly, other embodiments are within the scope of the following claims.
• For example, whilesupport wires824 and826 are illustrated above as largely symmetrical, with824 and826 arranged on either side ofimplant device400, this need not be the case. For example, in some embodiments, one wire is removed such thatimplant device400 directionally expands predominantly in only one direction when initially expelled from a cannula. This is illustrated inFIG. 13, where an embodiment ofimplant device400 includes only onesupport wire824. Referring toFIG. 13A, whenimplant device400 is initially expelled fromcannula310,implant device400 expands outward in a posterior direction, while it remains relatively unchanged in the anterior direction. Asimplant device400 is inflated, expansion begins largely in the posterior portion expanded bywire824, as illustrated inFIG. 13B. As inflation continues, the inflation substances are eventually distributed more evenly. Whenimplant device400 is fully inflated, as illustrated inFIG. 13C,implant device400 is once again symmetrical. In some embodiments, filltube1106 is also made of a memory material alloy, such as nitinol, other shape memory alloy or a shape memory polymer, and is arranged to oppose the directional expansion ofwire824. In this manner, the expansion characteristics ofimplant device400 may be varied to allow direction expansion whendevice400 is initially placed, but to ensure symmetrical expansion whendevice400 is fully inflated. Such embodiments are particularly advantageous whencannula310 is inserted obliquely into an intervertebral disc, for example as illustrated inFIG. 13. In these embodiments, initial expansion ofdevice400 occurs largely in the posterior direction, reducing anteriorly-directed pressure against the annular fibrosis untildevice400 approaches its fully inflated state. Further, such embodiments allowdevice400 to fit more precisely against the annular fibrosis, as the anterior portion (without a support wire) is relatively flexible and can easily conform to the inner surface of the annular fibrosis.
• Fill stylus1112 is described above as generally of a cylindrical shape. In some embodiments, the leading tip of fill stylus1112 may have a bent or bendable leading tip, as illustrated inFIG. 13. As illustrated inFIG. 14A, fill stylus1112 may have aflexible portion1402, such thattip region1404 may be articulated independently ofbody region1406. In some embodiments, portion1302 is a flexible material such as a rubber or silicone, such thattip1404 moves when met with sufficient physical resistance. In some embodiments, the orientation ofportion1402 may be selectable by an operator, such that degree of bending may be selectively controlled during operation. As illustrated inFIG. 13B,tip region1404 andbody region1406 may instead be connected by abent region1408. Bent region may be made of a memory material, such as nitinol, such that fill stylus1112 may be deployed into the annular fibrosis through a cylindrical cannula, but while bend atregion1408 upon exiting the cannula, such thattip region1404 is angled away from the axis of insertion.
• In some embodiments,implant device400 may be filled in a curable silicone, a curing compound, and an accelerating agent, such that the curing rate of the silicone may be modified as desired. Curing compounds and accelerating agents include platinum and platinum based compounds. Ultraviolet radiation, infrared radiation, and radio frequency excitation can also be used to cure the silicone. One or more of these materials may also include imaging contrast agents in order to provide imaging contrast for imaging modalities commonly employed in interventional radiology. Imaging modalities may include fluoroscopy, magnetic resonance imaging (MRI), computed tomography (CT), X-ray imaging, positron emission tomography (PET), or other medical imaging technique. Materials may include radiopaque materials, such that they are provide imaging contrast during x-ray or fluoroscopic procedures, paramagnetic or super paramagnetic materials, such that they provide imaging contrast during MRI, or other contrast agents commonly used with other imaging modalities.
• In some embodiments, silicone instead be cured in other methods, such as though the application the UV energy or heat. In these embodiments, UV energy or heat may be applied through a tool adapted to fit intoouter cannula310 and operate withinannular fibrosis202. In some embodiments, fill stylus1112 may include UV or heat energy-emitting elements, such that it may both fill and cure silicone.
• In some embodiments,outer cannula310 may additional include avent channel1504, such that air may be evacuated from within the surgical area during operation. This may be particular advantageous, for instance, during the insertion and inflation ofimplant device400. Asimplant device400 is inflated, displaced air is evacuated from the annular fibrosis, ensuring that no pockets of air become lodged within the annular fibrosis. Thisvent channel1504 may be defined by aspacer element1502, for example as illustrated inFIG. 15.Spacer element1502 is tubular in shape and adapted to sildeably insert intoouter cannula310.Spacer element1502 andouter cannula310 are loosely connected to allow for air or other material to escape throughvent channel1504 when tools or materials are inserted into and advanced withinspacer element1502, for example as illustrated inFIG. 16. In some embodiments, avent channel1504 may be integrally defined intoouter cannula310 to similarly allow for the escape of air.
Alternate Embodiment of the Implant Device
• In another example embodiment of an inter-vertebral implant device designed for percutaneous delivery and deployment, the implant device is likewise longitudinally collapsible for ease of insertion into a delivery cannula and is radially and longitudinally expandable within the disc space void following a percutaneous nuclectomy.
• The implant device includes an outer textile band, for reinforcement of the annulus fibrosus and for stabilization of the vertebral segment. The band allows expansion of the nuclear implant to variable sizes in order to accommodate the size of the nuclear space following nuclectomy (nuclear removal), and to insure adequate contact with the inner wall of the annulus fibrosus. The band prevents migration of the implant device and provides support and stabilization function for the annulus fibrosus weakened by degeneration. The band also provides dynamic stability to the vertebral segment by limiting excessive mobility including abnormal degrees of forward and lateral bending, subluxation, and torsion. Thus, it restores support functions similar to the healthy annulus fibrosus. It also relieves the stress on the damaged annulus fibrosus by acting as an annular detente and redirecting the forces of outer expansion inwardly towards the inner gas chamber, thus promoting healing.
• The annular reinforcement band is constructed of two hollow tubular braid sections that are overlapped and affixed to form a complete circle. Overlap of the lateral margins of these sections further reinforces the band. The textile reinforcement band is designed to be radially self-expanding and assume a C-shaped configuration by inserting a circular nitinol wire within its lumen to keep the braid flat and taut. The circular nitinol wire is restrained within the confines of the tubular braid and assumes an elongated oval shape, providing longitudinal expansion of the braid. The constrained nitinol wire also has memory to maintain the wire in a C configuration as viewed from the top, when expanded, providing radial expansion of the braid. The overlapped segments of tubular braid do not contain nitinol wire and are affixed to the outer margins of the dual-valve member and the tip-retainer member. Four fiber hinges are thus created at four corners of transition between the looping segments of nitinol wire constrained within the fiber braids and the overlapping lateral segments of the braids affixed to the outer margins of the dual-valve member on one side and the tip-retainer member on the other. Wire also has memory to maintain the wire in a C configuration as viewed from the top when expanded, providing radial expansion of the braid. Once the implant has been properly deployed within the disc space, it radially self-expands to come in intimate contact with the inner annulus. Inflation of the outer chamber with in-situ curable silicone, and the inner chamber with gas further applies outward pressure of the band and fixes it snugly along the inner annulus. Advantageously, it substantially conforms to the shape of the inner surface of the annulus.
• Forming the reinforcement band out of a flattened tubular braid allows unhindered sliding motion between the two layers of the braid. This allows the outer layer of the braid, which is applied snugly against the inner annulus, to remain static while the inner layer retains its mobility. This promotes tissue ingrowth into the outer layer, promoting healing by allowing unhindered incorporation of the implant unto the annulus fibrosus. This also allows the nuclear implant to be removed at a later date if necessary, since the inner layer of the textile braid is unlikely to fuse to the annulus due to the sliding motion between the two layers.
• The type of tubular braid used to form the reinforcement band may be varied. More specifically, the tubular braid of the present invention may be formed from a simple three yarn tubular braid or may be formed from a three dimensional braid. The flexible reinforcement band should accommodate a wide range of diameters reducing the need to precisely match the dimensions of the band to the outer circumference of the disc space.
• A favorable combination of strength and flexibility can be achieved by selecting textile braids with particular properties, and by arranging these strands in particular ways, for example by altering the braiding angles of the strands and their axial spacing. Several textile braid constructions are contemplated that combine different kinds of strands, for example multifilament yarns, monofilaments with inter-braiding of a plurality of structural and textile strands that may be compliant or non-compliant. This achieves an integrated fattened tubular braid of structural braid of compliant and non-compliant structural strands and textile strands.
• In one embodiment, the structural strands are polymeric and selectively shaped prior to the inter-braiding step. These can be formed into a variety of shapes that impart a predetermined configuration to the reinforcement band, most preferably helical. These are preferably wound as to sets of helices running in opposite directions.
• In some embodiments, three-dimensional braiding is used instead of two-dimensional braiding, since three-dimensionally braided structures may have a more even distribution of forces among the strands.
• Multi-filament yarns are also utilized, which have the advantage of a high degree of compliance and provide the needed flexibility to the band.
• The tubular braids are designed to radially self-expand, with the help of the nitinol wire, with a force sufficient to allow proper deployment of the nuclear implant. However, the force of self-expansion provided by the nitinol wire is insufficient to anchor the implant against the inner annulus. Additional force is provided by the inflatable components and under image guidance and pressure monitoring during the procedure, whereby the band is forced radially outwardly into contact with the inner annulus. Measures are taken during manufacture to insure that the textile band, once the nuclear implant is deployed and inflated, will radially expand to the proper dimensions. This generally requires a careful matching of the reinforcement band dimensions to the nuclear cavity. Over-expansion of the implant places unnecessary stress on an already damaged annulus. Under expansion of the implant may result in inadequate contact of the reinforcement band with the inner annulus and migration of the implant may occur.
• The degree to which the textile may stretch to substantially conform to the shape of the nuclear cavity is radially adjustable. Thus, the circumference of the nuclear space following nuclectomy need only to be approximated as described below.
• In one embodiment, a thermoplastic yarn is used, and upon heat conditioning in the radially contracted state, the tubular braid becomes heat-set with elastomeric memory and intrinsic tendency to return to this state. This allows for easier folding of the implant to minimal profile for insertion into the delivery cannula during manufacturing. When released from the delivery cannula and deployed within the disc space, the braid has the flexibility to stretch or expand to the required dimensions, to a certain degree.
• Since the self-expansion of the annular band is dependent on the shape memory of the incorporated nitinol wire, it is not necessary to include similar self-expansion memory properties in the braid. However, in some embodiments, such memory properties may also be included in the braid.
• In another embodiment, to achieve a radially adjustable annular band, the braid may be formed on a specially designed mandrel having a circumference equal to the maximum expected circumference of the band. The width of the band can also be chosen accordingly.
• In another embodiment, the tubular braid may be braided at a larger size and heat-set at a smaller size.
• In order for the annular band to control the amount of expansion of the nuclear implant additional yarns that have limited compliance are braided into the structure. These additional yarns may course in a serpentine fashion along the radial and longitudinal axis of the braid in order to limit extreme degrees of radial and longitudinal mobility. This is designed to restore dynamic stability of the vertebral segment.
• The implant device may also include an inflatable outer silicone membrane for containment of an outer chamber to be filled with in-situ curable rubber. The inflatable outer membrane has a generally discoid configuration upon inflation within the disc space. It has two mouth portions diametrically opposed from one another which are bonded to the outer faces of the dual-valve member on one side and the tip-retainer member on the other.
• The implant device may also include an inflatable inner silicone membrane for containment of an inner chamber to be filled with gas. It has two mouth portions which are bonded or crimped into annular grooves formed around inward segments of the dual-valve and tip-retainer members.
• The implant device may also include a dual-valve member that provides a reversible fluid communication with an inner and outer chamber. The dual-valve member can assume a closed configuration and an open configuration for both pathways.
• The dual-valve member also provides surfaces for secure attachment of the textile band, and the outer and inner membranes, and a weight-bearing function after it is incorporated with the cured silicone in the outer chamber.
• The dual-valve member includes a body being formed of a resilient material, such as silicone, having an elongate passageway extending there through, and two transverse pathways diametrically opposed from one another extend from the elongate passageway, substantially perpendicular to the longitudinal access, for delivery of curable silicone to the outer chamber of the nuclear implant.
• In some embodiments, the body is shaped generally as a stepped cylinder that in cross-section has a straight-oval configuration. An outer surface of a body tapers inwardly to form an annular channel to secure the inner membrane to the dual-valve member proximally and to the tip-retainer distally. The body may be formed of any durable polymer that is pliable and resilient, such as silicone.
• The outer chamber sealing member is shaped substantially as a smooth cylinder with the tubular member extending longitudinally in its center. It fits loosely within the elongate passageway formed in the body of the dual-valve member described above. It is formed of a thin-walled rigid material such as a polymer, and its surface is covered with a pliable and soft material that is capable of forming a seal when abutting the material of the body of the dual-valve member. In one embodiment, two protruding bosses are disposed along the outer margin of the outer chamber sealing member. These bosses are under tension and upon alignment of the aperture with the radial channels, the bosses snap outward into the radial channel, achieving a more secure occlusion on the fluid pathway.
• The sealing member, with the tubular member affixed in its center, is translatable distally in the open configuration along the longitudinal axis wherein the sealing member uncovers the transverse pathways permitting fluid communication with the outer chamber, and occluding fluid flow in the closed configuration. Simultaneously, the tubular member is translatable distally, in unison, in the open configuration, exposing the lumen of the tubular member to the inner chamber, and is translatable proximally, in the closed configuration for establishing a gas-tight seal of the side opening of the tubular pathway.
• The dual-valve member also includes a tubular member extending along a longitudinal axis of the dual-valve member and defining a second fluid pathway for delivery of gas to the inner chamber of the nuclear implant. The tubular member is open at its proximal end and closed at its distal end, and has a lateral opening at its middle section that is in reversible fluid communication with the inner chamber. It also provides mechanical support, stability, and proper alignment of the nuclear implant components especially during the process of nuclear implant deployment. The tubular member is made of shape memory material such as a metal (nitinol) or a polymer, to assume a C-shaped configuration when the implant is deployed in the disc space. The tip retainer member is guided posteriorly in order to orient the implant in the transverse plane of the disc. A flexible wire may extend through the gas passageway of the inflation stylus, and into the lumen of the tubular passageway of the nuclear implant, in order to provide further support and direction to the tip-retainer during delivery and deployment. The flexible wire is composed of shape-memory metal such as nitinol, and serves to guide the tip retainer into the transverse plane of the disc. The tubular member includes a connector terminal on the proximal end which is adapted to be coupled to the distal central aperture of the inflation stylus.
• When the tubular member is translated proximally, a seal of the lateral opening of the tubular pathway is established, forming a gas tight sealing engagement. When the tubular member is translated distally, the lateral opening is in communication with the inner chamber and gas flow is established.
• The tubular member is connected to the sealing member of the outer chamber and is translatable distally, in unison, in the open configuration, exposing the side opening of the tubular member for fluid communication with the inner chamber.
• The sealing member of the inner chamber is cone shaped and is formed of a soft and pliable silicone.
• The anterior wall of the dual-valve member is a relatively firm yet resilient plate that extends radially. It provides distal containment of the compression springs. It also provides a counter force for the crimping of the annular ring that secures the inner membrane to the body of the dual-valve member.
• At least two compression springs are interposed between the sealing member proximally, and the anterior plate distally. They are rendered in the constrained state by being anteriorly displaced by the inflation stylus. Enough energy is stored in the springs such that upon removal of the inflation stylus, the sealing member and the tubular member are displaced proximally, sealing both chambers.
• The dual-valve member also includes a tip-retainer member, identical in surface features to the dual-valve member, that serves as the opposing site for attachment of the inner and outer membranes, and the textile band. However, the tip-retainer member does not provide a valve function. Instead, it harbors a longitudinal channel along its center for loose containment of the distal end of the tubular member.
• The dual-valve member also includes a male inflation stylus for use with the female dual-valve member. This inflation stylus provides a fluid path for delivery of curable silicone to the outer chamber and a concentric central path for delivery of gas to the inner chamber. The inflation stylus includes an elongate nozzle that engages a receiving end of the nuclear implant so that the two components are removably engaged to one another, establishing alignment between the side opening of the inflation stylus with the transverse pathways of the body of the dual-valve member, thus establishing open fluid pathway communication with the outer chamber. The proximal aspect of the nozzle includes external threads that enable the nozzle to securely engage internal threads of the female body dual valve member by rotating the inflation stylus relative to the dual-valve member.
• The steps of securing the male to female components are described below. The user begins by priming the inflation stylus with curable silicone. The user then positions the inflation stylus so that the distal face of the stylus abuts the proximal face of the sealing member at the inlet port. The user next applies digital pressure to push the sealing member distally until the threads of the inflation stylus engage the threads of the dual-valve member. At that point the user twists the inflation stylus while holding the delivery cannula containing the nuclear implant steady so that the engaged threads cause the inflation stylus to advance farther until the side openings of the inflation stylus are in perfect alignment with the transverse radial pathways, opening fluid communication between the inflation stylus and the outer chamber. Simultaneously, the tubular member advances the side opening of the tubular member, opening gas communication with the inner chamber.
• In one embodiment, the inflation stylus stops advancing when the distal face of the nozzle contacts a proximally facing annular shoulder on the body of the dual-valve member.
• When the nuclear implant is inflated to a desired size, the inflation stylus may be disconnected from the dual-valve member. To disengage the inflation stylus, the operator rotates the stylus in the opposite direction with respect to the dual-valve member. As the nozzle of the inflation stylus rotates, the engaged threads causes the nozzle to withdraw from the dual-valve member, and the sealing member and the tubular member are pushed back by the springs to the original positions, sealing both pathways. When the threads have completely disengaged, the operator pulls out the inflation stylus.
Alternate Embodiment of the Delivery Apparatus
• In another example embodiment of the delivery apparatus, use of the delivery apparatus allows for placement of an access cannula into the intervertebral disc from a percutaneous poster-lateral approach, use of a mechanical nuclear evacuation device introduced via the access cannula into the disc space, and delivery of a mobile nuclear implant loaded in the delivery cannula introduced through the access cannula.
• The apparatus includes an assembly shaped to accommodate the anatomical profile of the disc by having a straight-oval cross-section. The assembly includes a guide needle with a sharp pointed stylet, and an obturator that fits within the guide needle after the stylet is removed. The obturator has a blunt tip (to insure safety of cannula insertion into the disc space), an intermediate dilator body of uniform diameter, and a tail section of a smaller diameter. A shoulder is formed at a point of juncture between the intermediate end tail sections.
• The apparatus includes a series of elongated tubular dilators adapted for telescopic mounting over the obturator. The dilators are tubular in construction and straight-oval in cross-section, and are sized to fit snugly over each in telescopic manner. The dilators have tubular walls and are successively larger in diameter. Each dilator has a distal end, intermediate body, and a proximal end. A shoulder formed in the proximal end provides blocking means to restrict forward movement of the dilators over each other. The proximal aspect of each dilator has a flat surface with a central opening that accommodates the proximal thin section of the obturator.
• An access cannula fits over the largest dilator and has a working channel. In some embodiments, this channel is approximately 5×8 mm. The access cannula lacks a fixed proximal blocking means. Instead, it has a removable cap, allowing for removal of the dilators while maintaining the access cannula in position.
• A nuclear evacuation device and a nuclear implant are insertable into the working channel of the cannula. The removable cap is oval, and is generally cylindrical in shape. It has a flat top portion and a collar portion. The top portion has a centrally located opening that accommodates the tail section of the obturator. The collar portion fits loosely over the proximal end of the access cannula. The distal end of the access cannula is slanted, allowing for guidance such as a nuclear evacuation device or disc implant, into the disc space at a transverse orientation. Alternatively, the distal section of the access cannula may include a slanted redirecting element such as a curved or inclined surface. This surface may be concave and configured to conform to the convex surfaces of inserted delivery systems, nuclear evacuation device, or nuclear implant.
• A perforated mallet fits over the smaller diameter tail section of the obturator and is used to introduce the dilators by tapping over the shoulders of the dilators and the cap component of the access cannula.
• The proximal end of the access cannula is secured to the skin of the patient by an adjustable retaining ring, which is slid over the access cannula. A tightening screw is provided for secure yet adjustable fixation. The adjustable retaining ring secures the cannula tip firmly in place within the annulus fibrosus to prevent it from slipping. The ring encircles the cannula and is translatable along the length of the cannula. It is also provided with a flange for increased contact of the access cannula on the skin surface.
• A thin-walled delivery cannula acts as a sleeve containing the folded nuclear implant in its proximal lumen. It is slidable into the access cannula in a loose fit, allowing for trapped air in the more distal aspect of the cannula to escape, as the loaded delivery cannula is advanced into the access cannula. The slanted tip of the delivery cannula is blunt and extends slightly beyond the sharp slanted tip of the access cannula.
• In an example implementation, the delivery apparatus may be carried out under local anesthesia and conscious sedation, thus avoiding general anesthesia. First, the guide needle is inserted under imaging observation into the back of a prone patient in a postero-lateral approach. The needle is advanced in an oblique direction, (such as at an angle of 25 degrees with respect to the perpendicular plane), until the sharp tip of the stylet is inserted into the annulus fibrosus. The stylet is withdrawn and replaced by a blunt-tip obturator, which is advanced further into the disc space. The needle is then withdrawn, while the obturator is held in place by the operator. A series of dilators are sequentially introduced telescopically until their distal ends reach the inner margin of the annulus. The access cannula may then be inserted into the disc space. The cap is removed while the access cannula is held in place by the operator, and the obturator and dilators are then withdrawn together.
• A nucleotome designed to fit loosely in the lumen of the access cannula is introduced through the access cannula and a complete nuclectomy is achieved. The nucleotome is then removed.
• The user then primes the inflation stylus with curable silicone, attaches the stylus to the proximal end of the nuclear implant, which is loaded in the proximal aspect of the delivery cannula, and then advances the inflation stylus with the nuclear implant therein to the tip of the delivery cannula. After the nuclear implant is deployed, inflated, and pressurized, the inflation stylus is disconnected and the delivery cannula, together with the access cannula, is removed.
• In an additional implantation of the present invention, a curable, flowable silicone is introduced into an implantable containment vessel in an uncured state. The silicone is then cured in vitro within the implantable containment vessel using a curing agent, UV radiation or RF excitation. For example, an implantable containment vessel, such as a balloon, bladder or the like, is implanted into a body cavity. Flowable curable silicon is injected into the implanted containment vessel using a syringe or specialized delivery stylus. In one implementation a curing agent, such as a platinum based compound is then injected into the silicone medium using either a syringe or an injection stylus. In another embodiment, a UV light source, such as a fiber optic cable is threaded through the syringe or provided in the specialized delivery stylus such that UV light is delivered to the injected silicone upon activation of the UV light source. In yet another implementation, flowable, curable silicone can be injected directly into to a body cavity, such as an evacuated intervertebral disk. Once delivered to the body cavity, the silicone can be cured as described above.
• While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular embodiments of particular inventions. Certain features that are described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.
• Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described components and systems can generally be integrated together in a single product or packaged into multiple products.
• Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims.

Claims (25)

What is claimed is:

1. An implantable prosthetic device comprising:

an inner chamber;

an outer chamber fluidly isolated from the inner chamber; and

a sealing valve in fluid communication with the inner chamber and the outer chamber, the sealing valve comprising a first sealing mechanism, a second sealing mechanism, and a stopper element;

wherein when the sealing valve is in an open state, the first sealing mechanism allows the inflow of a first material into the inner chamber and the second sealing mechanism allows the inflow of a second material into the outer chamber;

wherein when the sealing valve is in a closed state, the first sealing mechanism prevents outflow of the first material from within the inner chamber and the second sealing mechanism prevents outflow of the second material from within the outer chamber;

wherein a force applied the stopper causes the sealing valve to enter the open state; and;

wherein the release of the force causes the sealing valve to enter the closed state.

2. The device ofclaim 1, wherein the first material comprises an inert gas.

3. The device ofclaim 1, wherein the second material comprises a silicone polymer.

4. The device ofclaim 2, wherein the silicone polymer is curable.

5. The device ofclaim 1, wherein the second material comprises an imaging contrast agent.

6. The device ofclaim 1, further comprising an inflation device, the inflation device comprising:

a first channel; and

a second channel fluidly isolated from the first channel;

wherein the inflation device is adapted to apply the force to the stopper, position the first channel in fluid communication with the inner chamber, position the second channel in fluid communication with the outer chamber, and simultaneously transfer the first material from the first channel to inner chamber and transfer the second material from the second channel to the outer chamber.

7. The device ofclaim 1, wherein the prosthetic device is collapsible.

8. The device ofclaim 1, wherein inflating the inner chamber or the outer chamber with a material causes the prosthetic device to expand.

9. The device ofclaim 1, further comprising a memory material, wherein the memory material expands the device to a pre-determined shape.

10. The device ofclaim 1, wherein the device is adapted to fit into a surgical cannula.

11. The device ofclaim 1, wherein the device is adapted for use as an intervertebral disc prosthesis.

12. The device ofclaim 11, wherein the device a first vertebra against an upper surface and a second vertebra against a lower surface, such that the first vertebra is separated from the second vertebra.

13. A method of implanting a prosthetic device, comprising:

penetrating the annular fibrosus;

removing the nucleus pulposus;

implanting an inflatable device within the annular fibrosus, the inflatable device comprising:

an inner chamber;

an outer chamber fluidly isolated from the inner chamber; and

a sealing valve in fluid communication with the inner chamber and the outer chamber, the sealing valve comprising a first sealing mechanism, a second sealing mechanism, and a stopper element;

wherein when the sealing valve is in an open state, the first sealing mechanism allows the inflow of a first material into the inner chamber and the second sealing mechanism allows the inflow of a second material into the outer chamber;

wherein when the sealing valve is in a closed state, the first sealing mechanism prevents outflow of the first material from within the inner chamber and the second sealing mechanism prevents outflow of the second material from within the outer chamber;

wherein a force applied the stopper causes the sealing valve to enter the open state; and;

wherein the release of the force causes the sealing valve to enter the closed state.

14. An inflatable implantable device comprising:

an inflatable inner chamber;

an inflatable outer chamber, comprising a memory shape material adjacent the outer periphery capable of deforming from a first delivery shape, to a second, deployed shape;

an inflation valve in fluid communication with the inner and outer chamber and configured to receive and retain a first medium in the first chamber and a second medium in the second chamber.

15. The device ofclaim 14, wherein the inflation valve is configured to simultaneously inflate the first chamber with a first medium and the second outer chamber with a second medium.

16. A method of providing cured silicon to the body:

implanting an inflatable containment element in the body;

injecting a flowable, curable silicone into the containment vessel;

curing the injected silicone using either a curing agent or UV light.

17. The method ofclaim 16 wherein the implanted inflatable containment element is a balloon comprising an inner chamber fluidly isolated from an outer chamber, wherein the silicon is injected into at least one of the inner or the outer chambers.

18. A method of providing cured silicone to the body comprising:

creating a body cavity;

injecting a flowable curable silicone into the body cavity; and

curing the injected silicone using either a curing agent or UV light.

19. The method ofclaim 18 wherein the body cavity is made with a vertebral disc by removing the nucleus pulposus from within the annulus fibrosus; and wherein the silicone is injected within the annulus fibrosus.

20. A system for implanting an inflatable prosthetic vertebral nucleus comprising:

an access and delivery cannula having an inner diameter,

a nucleotomy tool for removal of the nucleus pulposus from a vertebral disc, wherein the nucleotomy tool is sized to fit within the inner diameter of the access and delivery cannula;

a delivery and inflation stylus for delivering an inflatable prosthetic implant, wherein the stylus is sized to fit within the inner diameter of the access and delivery cannula; and

an inflatable prosthetic disc implant comprising a first and second chamber, wherein the first and second chamber are fluidly isolated from one another, and the prosthetic disc implant is sized to be delivered through the access cannula by the delivery and inflation stylus to a position within the vertebral disc in an uninflated state.

21. A method for implanting an inflatable prosthetic vertebral nucleus, comprising:

penetrating the annulus fibrosus and accessing the nucleus pulposus of an intervertebral disk using an access and delivery cannula;

delivering through the access cannula a nucleotome that is configured to allow the removal of the nucleus fibrosis from the intervertebral disc while leaving the annulus fibrosus substantially intact;

maneuvering the nucleotome within the annulus fibrosus to remove the nucleus pulposus;

removing the nucleotome;

delivering a folded and deflated prosthetic implant through the access and delivery cannula and through the annulus fibrosus into the void formerly occupied by the nucleus pulposus;

inflating the prosthetic implant using an inflation stylus wherein the prosthetic implant is inflated with at least two mediums including a gas and a curable silicon;

curing the silicone within the prosthetic implant using a curing agent or UV light; and

removing the inflation stylus and the access and delivery cannula.

22. An access cannula for penetrating and accessing the annulus fibrosus of a vertebral disc comprising:

a proximal end;

a distal end;

an inner diameter sized to deliver one or more instruments or prosthetic devices;

wherein the one or more instruments include a nucleotome, a delivery stylus, or an inflatable balloon.

23. The access cannula ofclaim 22 wherein the proximal end is attachable to a light source.

24. The access cannula ofclaim 22, wherein the inner diameter is sized to fit around one or more access dilators.

25. The access cannula ofclaim 22 further comprising a set screw and adhesive set screw assemble.

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