Devices and methods for the restoration of a spinal disc

Background of the Invention

【0001】

The present invention relates generally to the treatment of spinal disorders or injuries, and more specifically to the restoration of the vertebral disc following surgical treatment. The present invention contemplates devices and methods for restoring normal disc space height and facilitating the introduction of biomaterials for use in disc repair and restoration.

【0002】

The intervertebral disc is divided into two separate areas: the nucleus pulposus and the annulus fibrosus. The nucleus pulposus is centrally located in the intervertebral disc and is surrounded and contained by the annulus fibrosus. The annulus fibrosus contains collagen fibers that are inserted between the endplates of adjacent vertebral bodies to form concentric thin plates surrounding the nucleus pulposus and to form a reinforcing structure. The chondrinous endplate is located at the boundary between the intervertebral disc and the adjacent vertebral body.

【0003】

The intervertebral disc is the largest avascular structure in the human body. The intervertebral disc receives nutrients and expels excrement by diffusion through the adjacent vascularized endplate. The hygroscopicity of the proteoglycan substrate in the nucleus pulposus functions to generate high intranuclear pressure. As the water content in the disc increases, the intrathecal pressure increases, causing the nucleus pulposus to swell and increase the height of the disc. This swelling places the fibers of the annulus fibrosus in an elongated state. A normal intervertebral disc has a height of about 10-15 mm.

【0004】

In general, there are many causes of disc destruction or degeneration that can be classified as mechanical, genetic and biochemical. Mechanical damage includes hernia formation in which a portion of the nucleus pulposus protrudes due to a tear or rupture of the annulus fibrosus. Genetic and biochemical causes can result in changes in the extracellular matrix pattern of the intervertebral disc and reduced biosynthesis of extracellular matrix components by the cells of the intervertebral disc. Denaturation is a progressive process that usually begins with a decrease in the ability of the extracellular matrix in the central nucleus pulposus to bind to water due to a decrease in proteoglycan content. The loss of water causes the nucleus pulposus to become dry, resulting in a decrease in fluid pressure within the disc and ultimately a loss of disc height. This loss of disc height causes the annulus fibrosus to buckle under no load and delaminate the cricoid lamella to form a cricoid fissure. Hernia formation may then occur when the laceration leads to protrusion of the nucleus pulposus.

【0005】

Proper disc height is necessary to ensure proper disc and column function. Although the main function of the intervertebral disc is to facilitate the movement of the spine, the intervertebral disc performs several functions. In addition, the intervertebral discs provide load bearing, load transfer and shock absorption between vertebra heights. A person's weight creates a compressive load on the intervertebral disc, which is not uniform in typical flexion movements. During anterior flexion, the fibers of the posterior annulus fibrosus are stretched, while the fibers of the anterior annulus fibrosus are compressed. Furthermore, when the center of gravity of the nucleus pulposus shifts from the center to the extended side, the nucleus pulposus moves.

【0006】

Changes in disc height have both local and global effects. Localized (or cellular, height) disc height reduction results in high pressure in the nucleus pulposus, which can lead to decreased cytosol synthesis and increased cell necrosis and death. In addition, the increased pressure within the disc creates an undesired environment for the movement of fluid into the disc, which further reduces the height of the disc.

【0007】

The decrease in disc height also causes a significant change in the overall mechanical stability of the spine. With reduced disc height, the small articular surface junction carries an increased load, may undergo hypertrophy and degeneration, and may even act as a source of chronic pain. The loss of disc height reduces the stiffness of the vertebral column and increases the range of movement, which can lead to further instability of the vertebral column as well as back pain. The outer annulus fibrosus provides stability under stretch-bearing conditions, and a well-hydrated nucleus pulposus maintains adequate disc height to keep the annulus fibrosus in a properly stretched state. At lower disc heights, the annulus fibrosus can no longer provide the same stability, resulting in abnormal binding behavior. This excessive movement itself manifests an abnormal load state of muscles, ligaments and tendons, which can ultimately be a source of back pain.

【0008】

Radical pain may occur due to the decrease in small hole volume caused by the lowered disc height. In particular, as the height of the intervertebral disc decreases, the volume of the small foramen through which the spinal nerve roots pass decreases. This reduction may lead to spinal nerve collisions with radiation pain and dysfunction.

【0009】

Finally, as the disc height drops to a predetermined level, the load on the adjacent compartment increases. The disc, which must support the additional load, undergoes accelerated degeneration and deformity, which may progress along the virtually unstable vertebral column.

【0010】

Despite all these injuries with disc height changes with gradual disc height changes, many of the adverse effects may be "acceptable" to the spine and the spinal system It may allow time to adapt to the gradual changes. However, the sudden decrease in disc volume caused by surgical removal of the disc or disc nucleus pulposus may exacerbate the local and overall problems described above. Many disc defects are treated by surgery, such as discectomy, in which the nucleus pulposus material is removed. During a complete discectomy, a substantial amount (usually all) of the volume of the nucleus pulposus is removed, which can result in a rapid loss of disc height and volume. Even partial discectomy can result in loss of disc height. Discectomy itself is the most common spinal surgical treatment often used to treat gut pain caused by collisions with nerves due to bulging discs or fragments of discs that come into contact with the neural structure of the spine. is there.

【0011】

Another common spinal surgery involves a discectomy followed by a transplant that introduces an artificial organ into the cavity that remains in the intervertebral disc gap when the nucleus pulposus is removed. The most prominent prosthesis so far is the "cage", which is structured to restore proper disc height and fix the adjacent vertebrae. These mechanical solutions employ a variety of forms, including solidified kidney-shaped implants, hollow blocks filled with bone growth material, indentation implants and screwed cylindrical cages.

【0012】

In more recent years, injectable biomaterials have been more widely considered to be enhancers for discectomy. In the early days like the 1962, Alf Nachemson suggested using a conventional syringe to inject silicone that vulcanizes at room temperature into the degenerated disc. In 1974, Lemaire and others reported Schulman's clinical experience with in vivo polymerizable disc prostheses. Since this time, many injectable biomaterials or skeletons have been developed as alternatives to the intervertebral disc nucleus pulposus such as hyaluronic acid, fibrin adhesives, alginates, elastinic polypeptides, collagen gels and others. .. Many patents have been issued for various injectable biomaterials. These patents include No. 6,423,333 (patent to Stedronsky et al.), No. 6,380,154 (patent to Capello et al.), No. 6,355,776 (patent to Ferrari et al.), Which describe crosslinkable silk elastin copolymers. ), Nos. 6,258,872 (Patent to Stedoronsky et al.), No. 6,184,348 (Patent to Ferrari et al.), No. 6,140,072 (Patent to Ferrari et al.), No. 6,033,654 (Patent to Stedoronsky et al.) (Patent to Ferrari et al.), No. 6,015,474 (Patent to Stedronsky et al.), No. 5,830,713 (Patent to Ferrari et al.), No. 5,817,303 (Patent to Stedronsky et al.), No. 5,808,012 (Patent to Donofrio et al.), No. 5,773,577 (Patent to Capello), 5,773,249 (Patent to Capello et al.), 5,770,697 (Patent to Ferrari et al.), 5,760,004 (Patent to Stetronsky), 5,723,588 (Patent to Donofrio) , 5,641,648 (patent to Ferrari) and 5,235,041 (patent to Capello et al.), 5,318,524 (patent to Morse et al.), Which describes protein hydrogels, 5,259,

【0013】

These references are for strong mechanical strength, promotion of tissue formation, biodegradability, biocompatibility, sterility, minimal cure or solidification time, ideal cure temperature and easy introduction into the disc space. Disclosed are biomaterials or injectable skeletons with one or more properties that are important for disc replacement, including low viscosity. The skeleton must not only exhibit the required mechanical properties, but also provide physical support. It is also important that the skeleton can withstand the multiple load cycles that the spine undergoes. The biocompatibility of the material is of utmost importance. Neither the initial material nor the degraded product should elicit an undegraded immune or toxic response, should represent immunoantigenicity, or should not represent cytotoxicity.

【0014】

Generally, the above biomaterial is injected as a viscous fluid and then cured in vivo. The curing method includes heat-sensitive cross-linking, photopolymerization, or addition of a solidifying agent or a cross-linking agent. The cure time of the material is important and should be long enough for the correct placement of the biomaterial during the process, yet short enough not to prolong the length of the surgery. If the material undergoes temperature changes during curing, the temperature increase must be small and the heat generated must not damage the surrounding tissue. The viscosity or fluidity of the material balances the need for the material to remain at the site of introduction into the disc, the ability of the surgeon to perform the placement, and the need to ensure complete filling of space or voids within the disc. Must be

【0015】

Regardless of the injectable skeletal material used, it is important that the completed surgery restores disc height. Therefore, it is important that the proper disc height is maintained while the biomaterial is being introduced into the space within the disc. Ideally, the disc height would be restored to a level equal to the height of the adjacent disc and indicating the normal disc height of a particular patient.

【0016】

However, if the disc height is not reestablished prior to the introduction of skeletal material, it will be impossible to replace the lost disc volume and at least restore the disc height prior to discectomy. Will. Failure to maintain the proper disc height when the biomaterial is introduced and cured in vivo can, in practice, lead to collapse of the disc space. This phenomenon is demonstrated by comparing the proper disc height in Figure 1a with the lowered disc height in Figure 1b. The lowered disc height shown in Figure 1b usually leads to a substantially complete discectomy if the adjacent vertebrae are not stretched. The patient can be placed in a position intended to open the disc space, especially on the posterior side of the disc D. However, it has been found that even due to spinal hyperflexion, the disc space does not reach its proper volume and ultimately does not approach the proper disc height shown in FIG. 1a.

【0017】

Traditional methods of implanting a sclerable disc prosthesis have relied on the physical placement of the patient or the infusion of biomaterial under pressure to obtain some elongation. However, these conventional methods do not establish a reproducible restoration of proper anatomical disc height during or after surgery. Ultimately, proper disc height will be established and maintained when the disc is replaced or enhanced with an injectable biomaterial.

[Summary of Invention]

【0018】

To meet the unresolved needs of conventional spinal surgery, the present invention contemplates a method of injecting a fluid material into the disc space. The method includes the step of forming an entrance into the annulus fibrosus connected to the space within the intervertebral disc and the step of packing a stretcher by cannulating into the entrance. According to one feature of the present invention, the extender has a structure that extends the vertebrae adjacent to the intervertebral disc space and establishes the intervertebral disc space height between the vertebrae adjacent to each other. The method of the present invention further steps to introduce a fluid material into the space within the disc through the lumen of the stretcher by cannulation while the stretcher maintains an established disc space height. Includes.

【0019】

In certain embodiments, the method of the invention includes the step of performing a discectomy after the entrance has been formed so that the extender creates a cavity in the space within the disc. In this embodiment, the step of packing the extender by cannulating includes the step of positioning the extender so that the extender cavity communicates with the cavity, and the step of introducing the fluid introduces the fluid into the cavity. Includes steps to do. Discectomy can be a complete discectomy that removes almost all of the nucleus pulposus from the disc space.

【0020】

In yet another feature of the invention, the fluid material is a curable biomaterial that is particularly suitable as a replacement or enhancer for the intervertebral disc. In this case, the step of introducing the fluid material can include keeping the extender in a packed position until the biomaterial hardens in vivo. In other words, the cannula-inserted stretcher keeps adjacent vertebrae stretched until the biomaterials harden. In this way, once the biomaterial has hardened and the stretcher has been removed, the proper disc height can be maintained and maintained.

【0021】

In certain embodiments, the fluid material can be introduced into the disc space under pressure. Another feature of the invention, which is particularly useful when pressure is applied to the fluid material, is that the cannula-inserted extender has a structure that seals the inlet into which the extender is packed. In some embodiments, the stretcher has a sized portion that substantially occludes or seals the annulus fibrosus entrance. In other embodiments, the extender comprises a sealing structure that compresses the annulus fibrosus material surrounding the adjacent vertebrae and / or entrances. This sealing structure can include a separate element such as a sealing ring that is integrated with or attached to the cannula insertion extender.

【0022】

Yet another feature of the present invention, which is also particularly suitable when pressure is applied to the fluid material, is provided with an outlet hole (vent) in the extender by insertion of a cannula. Thus, the fluid material can be introduced into the space within the disc until the fluid material exudes from the exit hole. Thus, the exit hole can provide a quick indication that the disc space has been filled.

【0023】

In some embodiments of the invention, the cannulating extender is engaged with a fluid infusion device. The device can come in a variety of forms, including pumps, syringes and gravity feeding devices.

【0024】

In other embodiments, the step of introducing the fluid material is to extend the tube into the lumen of the extender by cannulation, with the tube bound to the source of the fluid material to allow fluid to flow. Including that. This tube can be manipulated by a stretcher to guide the fluid material to a specific location within the disc cavity. For example, the tube can be moved by a gradual exudation action such that the fluid material is diffused throughout the disc space. At the same time, the tube can be gradually withdrawn from the extender lumen as the fluid material approaches the lumen opening.

【0025】

In a preferred embodiment, a sealing member is provided between the tube and the lumen. An outlet hole can then be provided separately from the cavity to indicate that the cavity is filled by exuding the fluid material from the outlet hole.

【0026】

In another embodiment of the invention, the device for injecting a fluid material into the disc space has facing surfaces configured to stretch adjacent vertebrae to the disc space distance. Includes members. This extending member has a base end and an end, and at least the end portion is shaped so as to be arranged in the intervertebral disc space. The stretching member further forms a fluid passage between the proximal portion and the distal portion, which passage has openings at the proximal portion and the distal portion. In some embodiments, the stretching member includes a fitting member associated with the proximal end of the stretching material to connect the stretching member to a source of fluid material for fluid flow.

【0027】

According to another feature of the invention, the device further includes an elongated cannula that penetrates the device to form a lumen. This cannula has a first fitting at the first end that is structured to be liquid tightly coupled to the fitting of the stretching member so that fluid can flow to the source of the fluid material. A second fitting portion constructed to be coupled to the can be provided at the opposite end. In a particular embodiment, the stretching member is integrated with the cannula and the second fitting is a fitting associated with the proximal end of the stretching member. In other embodiments, the stretching member is removable from the cannula.

【0028】

In a preferred embodiment, at least the end portion of the stretching member is bullet-shaped. In an alternative embodiment, the end portions are wedge-shaped, cross-shaped, I-shaped steel-shaped, or C-shaped with opposing substantially flat sides.

【0029】

The fluid passage of the extension member includes a central lumen, which has a large number of holes communicating with the central lumen. These holes can be arranged at the end portions of various shapes to guide the fluid material to a suitable location within the disc cavity. The stretching member can also define a separate hole from the fluid passage. In certain embodiments, the fluid passage may be in the form of a gap connected throughout the material of the stretching member.

【0030】

In a preferred embodiment, the stretch member is made of a biocompatible material such as stainless steel or titanium. In alternative embodiments, other biocompatible materials such as polymeric materials can be used, and even bioreabsorptive materials can be used. According to one feature, the stretching member is structured so that once the fluid material is introduced into the disc cavity and, if necessary, cured, it is removed from the disc space . In other features, the stretch member is most preferably structured so that it stays in the disc space when the member is made of a bioreabsorptive material.

【0031】

The stretching member can include a sealing member associated with a proximal end portion of the distal portion, the sealing member being constructed to provide a substantially liquid-tight seal within the disc space. The sealing member can include a number of sealing rings provided at the end portion. The sealing ring can be an elastic ring that is integrated with the end portion or attached to, for example, the end portion.

【0032】

One object of the present invention is to provide a system and a device for maintaining and strengthening an appropriate intervertebral disc space when an intervertebral disc prosthesis is introduced into the cavity of the intervertebral disc space. Another object is achieved by a feature of the invention that allows the introduction of fluid material into the disc space while maintaining the integrity of the height of the stretched adjacent vertebrae and disc. Other objects and advantages of the present invention can be recognized from the following description and accompanying drawings.

Description of Preferred Embodiments

【0033】

To enhance understanding of the principles of the invention, reference is made to embodiments shown in the drawings and described in the following specification. It should be understood that it is not intended to limit the scope of the invention to these embodiments. In addition, the invention includes many alternatives and variations to the illustrated embodiments, and further includes yet another use of the principles of the invention that can be commonly conceived by those skilled in the art in the art to which the invention belongs. It should also be understood.

【0034】

The present invention contemplates methods and devices that are packed after removing a portion or nearly all of the original nucleus pulposus of an intervertebral disc. One important object of the present invention is to maintain proper disc height during the introduction of biomaterials intended to replace the removed nucleus pulposus material. Removal of disc material can be achieved chemically, as by the use of chymopapain. However, more common methods can be performed as microscopically assisted visualization or open surgery with percutaneous access.

【0035】

Typical percutaneous discectomy is shown in Figures 2-4. In the first step, a guide wire G is guided into the affected disc D between two vertebrae, such as the L2 and L3 lumbar vertebrae. As shown in FIG. 3, the guide wire G preferably penetrates the annulus fibrosus A and the nucleus pulposus N and is fixed to both sides of the annulus fibrosus A. The guidewire G can be placed to orient the guidewire G correctly within the disc D by indirect vision such as X-ray fluoroscopy, or stereotactically, or by using other known methods. .. The method shown in the drawings uses a preferred rearward approach for the realization of the present invention. Of course, other methods may be used for discectomy according to known surgery. In addition, the access location may be dictated by the disc fissure or herniated disk formation location.

【0036】

A perforator T is driven along the perimeter of the guide wire and driven through the annulus fibrosus A, thereby forming the entrance to the disc nucleus pulposus. As shown in FIG. 4, the tissue remover R can be entered through the perforator T or through a machining channel cannula aligned with the disc entrance. Device R can then be used to remove all or part of the nucleus pulposus N of the disc D. As shown by the dotted line in FIG. 4, a second perforator T'is used to form a second annulus fibrosus entrance to facilitate complete removal of the nucleus pulposus of the disc. Can be done. Tissue removers R for introducing chemicals such as Kimopapine into the kernel space are of various types such as bone forceps, tissue excisors, rotary and / or reciprocating vacuum boost cutters and chemical introducers. Can be. Removal of the nucleus pulposus leaves a cavity C surrounded by a substantially intact annulus fibrosus A (see Figure 5).

【0037】

The present invention is intended to introduce a biomaterial into the disc cavity C that is capable of or restores disc height and preferably substantially normal disc function. For example, any of the above biomaterials can be filled into newly formed cavities. According to a preferred embodiment, the biomaterial is a fluid with suitable fluidity and / or viscosity. In particular, the biomaterial must have sufficient fluidity to allow relatively easy introduction into the disc cavity C and sufficient viscosity to retain its shape within the disc. Since the material used to fill the disc cavity C is a fluid, the present invention provides a means of maintaining a suitable disc height as the material flows into the cavity, thereby providing a cavity. That is, the volume of the implant biomaterial is the same as the volume of the nucleus pulposus removed by discectomy. In addition, the methods and devices of the present invention provide means for maintaining the volume of the cavity when the biomaterial transitions to the solid state.

【0038】

Therefore, as shown in FIGS. 5 to 8, a cannula-inserted extender 10 is provided according to one embodiment of the present invention. The extender 10 includes a terminal 12 extending into the disc cavity C and a proximal end 14 configured to engage a device for injecting biomaterial into the disc space. The extender 10 includes a cannula 11 terminated by an extension tip 18 provided at the end of the device. The lumen 16 is formed from the base end 14 to the extension tip 18 along the entire length of the device. The extension tip 18 is sized to extend through the entrance formed in the annulus fibrosus A of the intervertebral disc (see FIG. 3). The extender 10 can include a shoulder 20 in close proximity to the extension tip 18, which shoulder is sized to block through the annulus fibrosus entrance. The shoulder portion 20 can function to limit the distance that the extension tip 18 extends into the disc cavity C. The extender 10 may be provided with means for temporarily fixing the extender in place or supporting the extender on adjacent vertebrae.

【0039】

As shown in FIG. 7, the extension tip 18 is intended to be inserted through the annulus fibrosus entrance and is shaped to restore proper intervertebral disc height within cavity C. Thus, in one embodiment, the stretched tip 18 can include a tapered tip portion 24. This tip 24 can be introduced into the cavity C, the tip will be further penetrated into the cavity, and as the tip 24 presses on the end plate E of the disc, it will gradually stretch the adjacent vertebrae. .. In certain embodiments, the tapered portion 24 can be approximately bullet-shaped, as shown in FIG. In this shape, the extension tip 18 can have any direction of rotation when the tip is inserted from the annulus fibrosus entrance.

【0040】

Alternatively, the extended tip can be shaped like a tooth tip 40, as shown in FIG. In this embodiment, the tip comprises a substantially flat side portion 50 facing each other and an intermediate edge 52 of the wedge portion 42. The tip 40 can be introduced into the disc space with the flat side 50 of the wedge facing the end plate E of the disc. Once the tip is well inside the disc cavity C, the tip can be rotated so that the edge 52 contacts the end plate and extends the end plate. The edge 52 itself can be wedge-shaped with the base end having a width greater than the end.

【0041】

Returning to FIGS. 6-8 again, according to one feature of the invention, the extension tip 18 includes a large number of lateral holes 30 and end holes 32, all of which communicate with the central lumen 16. As shown in FIG. 7, holes 30 and 32 provide an outflow route for fluid injected through the lumen 16. These holes are preferably oriented so that they are not obstructed by the vertebral endplate E. The extension tip 40 shown in FIG. 9 is also provided with a side hole 46 and an end hole 48 provided in the flat side portion 50. In this embodiment, the edge 52 does not need to include a hole as it is closed by contacting the end plate.

【0042】

Since the fluid is intended to be introduced through the extension tip, several mechanisms are provided to ensure a substantially liquid-tight seal at the entrance to the disc space C via the annulus fibrosus entrance. It is preferable to have. Thus, in one embodiment of the invention, the extension tip 18 may include an annular ring 26 intended to compress in a sealing relationship against the disc end plate E and / or the disc annulus fibrosus A. it can. The ring 26 can be integrated with the extension tip 18 or can be a separate component attached to the extension tip as in the form of an elastic sealing ring. The sealing ring can be mounted in an annular groove formed at the extension tip.

【0043】

The extender 10 includes a fitting 36 formed at the base end 14 of the cannula 11. The mating section 36 provides a means for forming a liquid tight bond to a device made to inject biomaterial into the intervertebral disc. One exemplary device 70 is shown in FIG. The injector 70 includes a chamber 72 for storing biomaterial. In some cases, the chamber 72 may constitute a number of chambers from which an injectable biomaterial is obtained by mixing various constituent materials. For example, certain substances may be curable in vivo and may require a combination of a substrate material and a curing agent. To facilitate mixing of biomaterial components, the syringe 70 can include a mixing chamber 74. A manual controller 76 can be provided that pushes the components in chamber 72 into the mixing chamber 74. Alternatively, the injector 70 can incorporate a mechanism that drives fluid from the injector by pressure, such as a syringe or pump.

【0044】

The injector 70 includes a fitting 80 that is structured to engage in a liquid-tight engagement with the fitting 36 of the extender 10 by cannulating. In a preferred embodiment, the two fittings 36, 80 represent the meshing component of a lure (LUER). The injector can include a nozzle 78 that extends into the cannula 11 or, more specifically, the lumen 16 when the injector 70 engages with a cannula-insertion extender. A grip member 82 can be provided to allow manual stability of the injector.

【0045】

As mentioned above, the cannulating extender 10 of the present invention may be used after discectomy. For the purposes of the illustration, it was assumed that a complete discectomy was performed, as shown in FIG. 5, in which substantially all of the bone marrow was removed, leaving a disc cavity. Of course, the principles of the present invention are equally well applicable when only a portion of the nucleus pulposus is removed by partial discectomy. When two lateral approaches (represented by the first and second perforators T and T') were used, one of the annulus fibrosus entrances was by a material compatible with the annulus fibrosus of the intervertebral disc. Can be sealed. Once the nucleus pulposus has been cleaned, the guidewire G can be repositioned within the disc D, also preferably using known guidance and positioning devices and techniques. The cannulating extender 10 can then be routed along the perimeter of the guidewire G until the extension tip 18 is properly positioned within the bone marrow cavity C. The proper depth of the extension tip 18 can preferably be determined by the shoulder 20 contacting the lateral annulus fibrosus A or by the mechanism of the associated depth contacting the adjacent vertebral body.

【0046】

At the extension tip 18, the tapered portion 24 gradually pulls the end plates E of the adjacent vertebrae apart as the extension tip is further driven into the disc space. A mallet, impact device or other suitable drive device can be used to push the tapered portion 24 into place with respect to the original tension of the annulus fibrosus of the intervertebral disc. It can be understood that the purpose of this step is to sufficiently extend the intervertebral gap to a disc height suitable for a particular spinal height. For example, for the L2-L3 disc space, a suitable disc height can be 13-15 mm so that the extension tip is located within the cavity C to achieve this amount of extension. As shown in FIG. 5, since the extension tip 18 always occupies a certain volume of the cavity C, it is preferable to use the only cannula-insertion extender 10. However, a second cannulation extender and associated extension tip may be required (as per the second annulus fibrosus entrance shown in Figure 4) to establish proper disc height. Absent.

【0047】

Therefore, it should be understood that this method is similar here for the extension tip 40. However, unlike the tapered extension tip 18, the extension tip 40 requires additional steps to extend the disc space. In particular, the extension tip 40 is initially inserted with the flat side surface 50 facing the end plate E. The tip must then be rotated until the edge 52 presses and supports the end plate. The flat side surface 50 can include an angled transition to the edge, or the edge 52 is rounded to facilitate extension when the extension tip is rotated in vivo. be able to.

【0048】

When an extended tip, such as tip 10, is inserted to a suitable depth into the cavity 10 of the disc, by contact of the shoulder 20 with the end plate E or the medial side of the annulus fibrosus, or by engagement of the ring 26. , The annulus fibrosus entrance is sealed. At this point, the biomaterial fluid can be injected into the stretcher by cannulation, especially into the lumen 16. To perform this step, an injector, such as the injector 70, can be engaged with the mating portion 36 of the base end 14 of the extender by cannulation insertion. Ideally, the guidewire G is removed and the syringe fitting 80 is engaged with the fitting 36. Nozzle 78 extends into lumen 16. The nozzle may be sized so that the outlet end of the nozzle is located near or within the extension tip 18. At this point, the injector 70 is activated according to its structure to allow the biomaterial fluid to move from the extender into the lumen 16. The biomaterial exits through holes 30, 32 in the extension tip 18 to fill the cavity C. The holes 30 and 32 are preferably arranged and sized to achieve complete and rapid diffusion of the biomaterial throughout the cavity. The purpose of this step in this process is to replace the total volume of cavities as well. If the fluid biomaterial is a material that can be cured or solidified in vivo, time may also be required to ensure a uniform volume once the material is completely cured.

【0049】

It should be clear that the extension tips 18, 40 maintain proper disc height during the injection of biomaterial. This tip can be held in place until the injected material hardens or solidifies. Once the material is sufficiently cured, the stretched tips 18 and 40 can be removed. Since the stretched tip occupies a certain volume, additional biomaterial can be injected from the tip when it is being withdrawn if necessary, thereby filling the gap left by the tip.

【0050】

In certain embodiments, the extension tip 18 is an assembly and can be removed from the cannula 11, as shown in FIG. Therefore, the tip 18 and the cannula 11 may be provided with a press fit (as shown in FIG. 9) or a removable meshing member 19 such as a screw or lure® as conceived by one of ordinary skill in the art. it can. The removable extension tip can serve several purposes. For one purpose, the injected biomaterial may require a long cure time. Of course, it is necessary to keep the extension tip in place in order to maintain proper disc height while the material is curing. However, it may not be necessary to hold other components of the device, such as the injector 70 and the cannula 11, in place. The extension tip of the assembly type allows the cannula 11 to be removed while the tip remains in place and acts as a disc spacer while the biomaterial hardens.

【0051】

Another hidden purpose of the removable extension tip 18 is achieved by an embodiment in which the tip is made of a biomaterial that allows the tip to maintain a presence within the intervertebral disc. In this embodiment, the stretched tip material must be compatible with the biomaterial used to replace the original nucleus pulposus. For example, if the biomaterial is only intended to restore disc height, but not the original biomechanical properties of the original nucleus pulposus, then the material for the extended tip 18 However, it is generally possible to provide a solid skeleton. On the other hand, the injected material is most preferably intended to function in a manner similar to the properties of the biomaterial of the intervertebral disc so that the spinal compartment functions as close to the normal spinal compartment as possible. In this example, the robust skeleton, of course, impairs the normal flexibility, compression and twist response of the disc. Thus, the extended tip 18 in the embodiment in which the tip is left in vivo can be made of a biodegradable substance that is absorbed into the substrate of the hardened biomaterial forming the nucleus pulposus of the intervertebral disc.

【0052】

It is preferred that the tip occupy as little volume as possible, regardless of whether the extension tip is removed or stays in the disc space. On the other hand, the extension tip must be strong enough to maintain the spatial height of the disc while extending the adjacent vertebrae. In the particular embodiment shown in FIGS. 5 and 7, an extension tip 18 is shown across a substantial portion of the nucleus pulposus cavity. Alternatively, the stretched tip can have a short length from the shoulder 20 such that the tip extends only partially into the cavity. The extension of the disc space can be assisted by a certain position of the patient on the operating table, where, for example, the anterior surface of the disc space is naturally extended by the position of the spine. Proper extension of the disc space may be better adapted by the anterior approach rather than the posterior approach shown in Figures 5 and 7.

【0053】

In an alternative embodiment, the extension tip can take a wide range of geometric structures, some of which are dictated by the annulus fibrosus formed during discectomy. In the embodiments of FIGS. 5-8, a circular annulus fibrosus entrance is formed and the circular extension tip 18 is used to seal the inlet. In some cases, a flat or wedge-shaped elongated tip similar to the tip 40 shown in FIG. 9 can be used where the hole through the annulus fibrosus has a larger area than the tip itself. In these cases, the extra space between the tip and the inner surface of the entrance can provide an opening for a direct visualization device or other suitable device. Preferably, this approach is more suitable when the biomaterial is not injected by pressure, for example when a gravity feeder is employed (see Figure 11 and its associated description below). In other cases, the surgeon performs a discectomy through a rectangular or circular entrance in the annulus fibrosus of the disc. Complementary shaped extension tips can be used to match and fill the annulus fibrosus entrance. For example, the extended tip can take the shape shown in FIGS. 12-14. A cross-shaped tip 55 with a central lumen 56 communicating with a large number of holes 57 is shown in FIG. It can be seen that the cross-shaped tip arms can have a thinner cross section than those shown in the figure if they are strong enough to support the vertebrae adjacent to their proper extension position. Similarly, the holes 57 can be distributed in various patterns through the hub and the cross-shaped legs.

【0054】

FIG. 13 shows an I-beam extension tip 60 with a central lumen 61 communicating with a large number of holes 62. The stretched tip 63 shown in FIG. 14 has a C-shape and includes a lumen 64 and a hole 65. These two steel shapes provide sufficient support for the required elongation. Similarly, the thickness of this steel arm can be reduced as needed to minimize the cross section of the extension tips 60, 63.

【0055】

Most preferably, the volume of the tip within the nucleus pulposus cavity C is minimized, regardless of the overall shape of the stretched tip. A wedge shape like the tip 40 may be preferable, but a bullet-shaped tip like the tip 18 is less desirable from this point of view. Further, regardless of the overall shape, the extended tip must communicate with the lumen and provide a means of draining from the tip. In the illustrated embodiment, the extension tips 18, 40 include orifices 30, 31 communicating with the corresponding lumen, respectively. Alternatively, the extended tip can be in the form of an open skeleton or skeletal skeleton. Similarly, the skeleton or skeleton must be strong enough to properly stretch the spinal space and maintain disc height over a suitable length of time. In some embodiments, the stretched tip can be in the form of a material with connected gaps, such as a porous material. The porous stretched tip can have a solid skeleton with multiple fluid passages through the material. The porous material can be a metal such as porous titanium, but after this process is complete, a porous polymer such as polylactic acid is preferred so as not to interfere with the visualization of the space in the spinal plate. ..

【0056】

In the method described above, the extension tip was described to provide a passage for injecting biomaterial into the nucleus pulposus C, following a discectomy. The extended tip of the present invention acts similarly well as a conduit for the introduction of other fluids into the spinal disc space. For example, the stretched tip is like the material disclosed in US Provisional Application No. 60 / 336,332, entitled "Pretreatment of Chondrinous Endplates Prior to Treatment of Intervertebral Discs with Injectable Biomaterials". Can be used to inject various biomaterials, the disclosures of this application are incorporated herein by reference. This provisional application discloses, for example, materials for pretreatment of the end plate of the intervertebral disc to improve the biological function of the degenerated disc. Cannula-inserted extenders of the invention, such as the extender 10, can be used first for the pretreatment of the intervertebral disc disclosed in the provisional application above. Once the pretreatment is complete, a cannula-inserted stretcher can then be used for injection of curable biomaterial.

【0057】

Similarly, the present invention can be used for multiple injections of fluid, including multiple injections to cure the biomaterial within the nucleus pulposus cavity C. For example, certain biomaterials may include a first component that is introduced into the disc space, followed by a second component or hardener. The second component can initiate curing of the resulting composition.

【0058】

An alternative embodiment of the present invention is shown in FIG. In this embodiment, a cannula-inserted extender 85, which generally includes a truncated conical extension tip 86 and a shoulder 87, is provided. The tip 86 acts as a wedge that stretches the disc space when the cannula-inserted stretcher 85 is packed into the disc space. The shoulder 87 acts as a stopper to the adjacent vertebral body to limit the distance the tip is driven into the disc space. The extension tip 86 has a length from shoulder 87 to its end that is sufficient to straddle the length of the entrance within the disc annulus fibrosus A but limits its length into the nucleus pulposus cavity C. Is preferable. In this embodiment, the extension tip 86 does not displace any substantial volume within the cavity C.

【0059】

The cannula-inserted extender 85 forms a lumen 88 that extends over the entire length of the extender. The lumen 88 is sized to accommodate the injection tube 94 therein. The injection tube 94 may include a fitting 96 for engaging with the injection device 98. The fitting 96 can be of any suitable type, such as the luer® type fitting described above. The injection device can be similar to the injector 70 shown in FIG. 10 or can take various shapes for the introduction of fluid into the disc cavity. In one embodiment of the invention, the biomaterial fluid is introduced into the cavity by gravity feeding. In this example, the infusion device 98 may simply be in the form of a reservoir with an air passage for allowing the biomaterial to flow downward into the disc space by gravity alone. Of course, the patient must be properly oriented to accommodate the gravitational filling of the disc cavity C.

【0060】

In this embodiment, the cannulated extender 85 functions as a support member or guide for the injection tube 94. The tube 94 can be in the form of a relatively large gauge needle with a smooth tip sized to accommodate the ideal flow of biomaterial into the disc space. The tube 94 can be introduced or removed through the cannula-inserted extender 85 (as indicated by the arrows in FIG. 11) as the biomaterial flows into the cavity C. Further, the diameter of the tube 94 can be large relative to the diameter of the lumen 88 such that the outlet hole 95 of the tube 94 can be pivoted in the cavity C by a sweeping motion. If a cannula-insertion stretcher is used to introduce the pretreatment material as described above, this mechanism is a drain hole for directing the pretreatment material to where it is needed. Allows 95 positioning.

【0061】

In certain embodiments, the lumen 88 may be provided with a sealing member 89, which may be in the form of an elastic sealing ring. The sealing member 89 can form a surrounding liquidtight seal on the injection tube 94, which is especially important when the biomaterial is injected under pressure. In addition, the sealing member 89 can function as a joint form for supporting the injection tube 94 when the drain hole 95 is manipulated within the disc cavity.

【0062】

In another feature of the invention, the cannulated extender can provide an outlet hole for drainage of excess biomaterial when the disc cavity C is full. Exit holes are particularly useful when biomaterials are introduced by gravity feeding. In one particular embodiment, an outlet hole 92 is provided in the extender 85. When the disc cavity is full, the biomaterial exudes through the exit hole 92 to provide a visual indication that the cavity is full. The outlet hole 92 preferably includes a tube that projects away from the extender 85 by cannulation in order to improve the visibility of the exit hole in vivo. Alternatively, the outlet hole can be formed by the diameter difference between the injection tube 94 and the lumen 88 in the absence of the sealing member 89.

【0063】

The outlet hole 92 is suitable for methods that include weight feeding of biomaterial into the disc space. However, the outlet hole can also be maintained open from the beginning as the biomaterial is injected from the injection tube 94 into the cavity C. When the cavity is completely filled, the biomaterial will seep out of the exit hole 92. At this point, the exit hole can be closed and additional biomaterial can be injected into the disc space to increase the pressure in cavity C. This injection through the outlet hole provides a quick indication that the cavity is full and provides a starting point for the introduction of a calibrated amount of additional biomaterial to establish the proper cavity pressure. be able to.

【0064】

In each of these embodiments, once the biomaterial has hardened and the cannula-inserted stretcher has been removed, the entrance to the disc annulus fibrosus has a newly formed disc for the prosthesis to prevent herniation. The material can be filled. The annulus fibrosus can be sealed with any suitable material such as fibrin adhesive or polymerizable material. The material used to seal the annulus fibrosus should be strong enough to remain intact when pressure in the disc increases due to spinal hydration or biomechanical movements. is there.

【0065】

According to certain embodiments, the cannula-inserted stretcher and in particular the stretcher tip described above can be formed of a variety of biomaterials. As mentioned above, the extender tip must be strong enough to maintain proper extension of the disc space until the biomaterial is sufficiently injected and hardened, if necessary. In certain embodiments, the stretched tip is formed of a biocompatible metal such as stainless steel or titanium. In other embodiments, the stretched tip is formed of a polymer or plastic that is preferably radiation permeable to allow visualization of the stretched tip in vivo to assess the location of components. To.

【0066】

Although the present invention has been illustrated and described in detail with reference to the drawings and the above description, these should be considered to be of an exemplary and non-limiting nature. It is understood that only preferred embodiments are provided and it is desired that all modifications, modifications and further uses contained in the spirit of the present invention be protected.

[Simple explanation of drawings]

【0067】

FIG. 1a-1b show a side view of the intervertebral disc and adjacent vertebrae showing the proper disc height (FIG. 1a) and lowered with a substantially complete discectomy followed. It is a side view which shows the height of an intervertebral disc.

FIG. 2 is a side view of an intervertebral disc and adjacent vertebrae in which guide wires are arranged according to one feature of the present invention.

FIG. 3 is a sagittal direction view of the intervertebral disc space shown in FIG. 2 with the perforator forming an entrance in the annulus fibrosus of the intervertebral disc.

FIG. 4 is a sagittal view of the intervertebral disc space shown in FIG. 3 in which a tissue stretching device is located within the nucleus pulposus of the intervertebral disc.

FIG. 5 is a sagittal direction view of the intervertebral disc space shown in FIGS. 2-4 with a cannulating extender according to one embodiment of the present invention.

FIG. 6 is a side view of a stretcher by cannulating according to one embodiment of the present invention.

FIG. 7 is a side view of the intervertebral disc space shown in FIGS. 2-5 with a cannula-inserted extender of FIG. 6 arranged within the intervertebral disc space.

FIG. 8 is a perspective view of the extension tip forming portion of the extender by cannulating shown in FIGS. 6 and 7.

FIG. 9 is a perspective view of a stretched tip according to an alternative embodiment of the present invention.

FIG. 10 is a side view of an injection device for use in one embodiment of the present invention.

FIG. 11 is a side view showing the intervertebral disc space with an extender by cannulation insertion according to yet another embodiment of the present invention.

FIG. 12 is a cross-sectional view of a cross-shaped extension tip according to one embodiment of a cannula-insertion extender of the present invention.

FIG. 13 is a cross-sectional view of an I-shaped steel-shaped stretched tip according to another embodiment of the cannula-inserted stretcher of the present invention.

FIG. 14 is a cross-sectional view of a C-shaped extension tip according to still another embodiment of the cannula insertion extender of the present invention.