The invention relates to a system and method for treating deformities and for reconstruction of soft tissue attachments of a mammalian skeleton. Particularly, the invention relates to a non-rigid system and method for stabilizing and balancing multiple bony motion segments. The invention also relates to a method of attaching autogenous or allogenic soft tissue to host bone for reconstruction of articular joint structures.
Skeletal deformities can have congenital and often hereditary causes and, if not treated, can result in severe health consequences. Among the numerous bones of a human or animal body, the spine, which is a flexuous and flexible column formed of a series of bones called vertebrae, is one of the most vital parts of the mammalian organism.
Ligament or tendon damage in the major articular joints is often caused by traumatic injury such as those seen in professional sports or motor vehicle accidents. The knee joint is comprised of the tibiofemoral and patellofemoral articular junctions and several major soft tissue attachments and is the most commonly reconstructed joint. It, along with other major articular joints, is critical to normal skeletal function.
Normally, the spinal column grows in line from the neck to the tailbone and, when viewed from the side, curves are seen in the neck, upper trunk, and lower trunk. The upper trunk has a gentle rounded contour called kyphosis and the lower trunk has a reverse of the rounded contour called lordosis. Certain amounts of cervical (neck) lordosis, thoracic (upper back) kyphosis, and lumbar (lower back) lordosis are normally present and are needed to maintain appropriate trunk balance over the pelvis. Deviations from this normal alignment may reflect abnormal kyphosis or lordosis when viewed from the side, or more commonly, scoliosis, when viewed from the anterior or posterior.
Under normal circumstances major joints consist of one or more articular junctions occurring between bony structures and several soft tissue (ligamentous and tendonous) attachments that are integral to motion and stability of the joint structure. Compromise of these soft tissue attachments results in partial to complete loss of joint function and stability.
Scoliosis is a sequential misalignment or deformity of the bones and discs of the spine and is manifested in the following ways. Firstly, the deformity can be an apparent side bending of the spine when viewed in a coronal plane from the front or back (anterior/posterior or AP view). Secondly, another way of diagnosing scoliosis is a loss of the normal kyphotic curvature in the thoracic or chest area when viewed from the side. This is a sagittal plane deformity. And thirdly, scoliosis can be observed as a result the rotation of the spine around its own long axis. This is an axial plane deformity. If scoliosis is left untreated, the curve can progress and eventually cause pain, significant cosmetic deformity, and heart, lung, or gastrointestinal problems.
Soft tissue damage leads to the loss of function, stability or alignment of the major articular joint structures and is diagnosed in the following manner. Firstly, physical examination of the joint and its motion characteristics may be performed to determine the extent of the loss of function and stability. Secondly, arthroscopic or radiographic, particularly MRI, methods may be used to further refine the physical diagnosis. Depending on the extent of the injury, some patients may function at an acceptable level without surgical intervention while others require major reconstruction to function reasonably well.
Treatment choices in scoliosis are determined by a complex equation, associated with the patient's physiologic maturity, curve magnitude and location, and its potential for progression. Treatment choices usually include bracing or surgery. Typically, the best treatment for each patient is based on the patient's age, how much more a patient is likely to grow, the degree and pattern of the curve, and the type of scoliosis.
The treatment choices for soft tissue injury are determined by a combination of patient activity level, age, physical health, extent of injury, and the likelihood of disease progression if the injury is left untreated.
The ultimate goal of treatment for scoliosis is the creation of desirable curvature in a portion of the spine. Some cases of scoliosis, if diagnosed at its earlier stages, can be managed without surgery. Otherwise, the curvature should be corrected by surgical procedures. Typically, a surgical procedure is associated with stainless steel or titanium rods affixed to the bone with hooks or screws, which then maintain the correction until fusion of multiple vertebral segments occurs. Surgery may be done from the front (anterior) of the spine or from the back (posterior) of the spine or both, depending on the type and location of the curve.
The treatment goal for soft tissue injury is to restore joint motion and stability to an acceptable functional level. A wide range of treatment options including surgical intervention may be used depending on clinical factors. Surgical treatment involves the repair or replacement of soft tissue elements with autologous or allogenic grafting materials fixed with screws, anchors or through biologic means. Surgery may be performed using open, minimally invasive, or arthroscopic methods. The surgical site and method are highly dependent on the location and extent of injury.
Overall, in addition to external bracing techniques, various surgical techniques are practiced to fuse the instrumented spinal segments. Some of the disadvantages and shortcomings of the surgery may include:
Various surgical procedures are performed to treat soft tissue injuries. Disadvantages of surgical intervention include:
To minimize at least some of the above-discussed disadvantages, it is known to use a cable system configured to maintain the desired position between multiple bones. U.S. Patent Application Publication No. 2003/0105459 discloses a stabilizing system including a plurality of inflexible cables each coupled to a respective fastener, which, in turn, is attached to a vertebral body. To generate a compressive force sufficient to maintain vertebral bodies in the desirable position, the free ends of the cables are coupled to one another.
In view of the aforementioned undesirable consequences posed by known rigid and non-rigid surgical systems directed to treatment for scoliosis, there is a need to provide a non-rigid system and technique for flexible correction of alignment between multiple bony portions, including spinal abnormalities producing significant curve correction, relative to one another while preserving much of the mobility of the bony portions to be fixed. This invention also can be used to reconstruct the soft-tissues surrounding major joints.
The inventive system and method utilize flexible material to tether multi-segmental portions of a bony structure, such as vertebral bodies, finger and other limb portions, together while allowing certain mobility therebetween during a corrective process. As a result of corrective loads generated by the inventive non-rigid system, deformed bony portions tend to restore a desired curvature and/or shape.
Accordingly, unlike known surgical systems and techniques, the inventive system includes a less invasive and less traumatic procedure. Furthermore, in most cases, post-operative casting and bracing may not be required, leading to an expeditious discharge of a patient from the hospital, with a more rapid progressive resumption of routine daily activities. The inventive system and method allow for correction of abnormal curvatures of the spine while preserving its relative mobility, and flexibility, which, in turn, leads to sound muscle tone, less inconvenience and, overall, improved quality of the patient's life.
Unlike conventional systems, the inventive system utilizes allograft/autograft fascia material, which is easy to remove or disable. Furthermore, if made from bioabsorbable materials, the removal of the fascia material is not necessary once correction of scoliosis is achieved.
The inventive system may be successfully applied to not only treatment of minor degrees of spinal deformity, but also can be applied to more severe cases or other situations where restoration of natural curvature or dynamic fixation/stabilization is desired. For instance:
Flexibility of the inventive tethering system allows for its easy attachment to the spine by a variety of fasteners advantageously overcoming the complexity of the known systems. In accordance with one feature of the invention, the fascia material including at least one band can be directly attached to a posterior element of vertebra(e). In accordance with a further feature, the fascia material can be attached to the vertebrae by means of variously shaped and dimensioned fasteners.
In accordance with a further feature of the invention, the flexibility of the tethering system provides for equally effective treatment of a single vertebral motion segment (vertebra-disc-vertebra), multiple vertebral motion segments and motion segments constituting a finger or any other bony motion segment of a mammal body.
Therefore, in certain embodiments the present invention provides a tethering system for the flexible correction of spinal abnormalities, including scoliosis, allowing for a substantial degree of mobility of the spine over a period of treatment. The tethering system may have a simple and effective structure configured to minimize abnormal spinal curvatures extending over multiple vertebrae as well as to treat a deformed single vertebra. The tethering system may have a structure that can be effectively utilized in any of anterior, posterior and/or anterior/posterior-lateral surgical approaches. The tethering system may have a flexible structure configured to attach to various vertebral bony structures, such as spinous processes, lamina, facets, pars, pedicles, as well as the vertebral body itself, and vertebral bodies in a relatively simple and efficient manner.
In accordance with other embodiments, the invention further provides various innovative methods of configuring the tethering system.
Accordingly, the invention provides minimally invasive method for fusionless treatment of abnormal curvatures, or other deformities, of the spine while preserving much of the spine's flexibility during the treatment period, minimizing hospital stays, associated with reduced postoperative pain and less visible scarring, and improving the overall quality of the patient's life including a quicker return to school, work and other activities enjoyed before surgery.
For the illustrative purposes, the following discussion will be mainly directed to the spine. It should be understood that the invention can be equally effective in treating deformities of fingers, toes, wrists, feet and other bony structures having at least one motion segment, which is composed of multiple bony portions.
As shown in
The tethering material may be made from fascia, which, as a term used in this disclosure, describes a single segment, length, piece, etc of tissue capable of maintaining the corrective loads between at least two bony members. As is known, the fascia extends under the skin to cover underlying tissues and to separate different layers of tissue. Accordingly, the flexible material 18, when comprising fascia, can be obtained from the patient's body and, in this case, be characterized as an “autograft” fascia. Alternatively, fascia may be obtained from a foreign body or material and, in this case, be termed as an “allograft” fascia. Structurally, the tethering material can include multiple pieces, bands, or loops, or a single continuous piece or loop.
The flexible material 18 (or tethering material) may comprise materials other than fascia. Other alternatives include fabrication of the tethering material in whole or in part from biocompatible fibers of a native, biosynthetic, or synthetic polymeric, connective tissue or plant connective tissue-like characterized by the biocompatibility of the selected material. The tethering material may be resorbable or degradable to eliminate the necessity of the secondary operation directed exclusively to the removal of the tethering material once the correction is achieved. Alternatively, the tethering material can comprise non-resorbable polymers, metals, etc., similar to a flexible wire or cable. Overall, the tethering material can include abdominal peritoneum, tendons, small intestine submucosa, perichondrial tissue, completely or partially demineralized bone, ligament, silk, collagen, elastin, reticulin, cellulose, and a combination thereof.
The physical properties of the tethering material 18 such as length and number of pieces, loops or segments, which may or may not be braided, like a rope, or be tied together, are selected to generate a predetermined sufficient force. As a result, the tethering material may be pre-packaged in discrete lengths, loops or segments, various thickness/diameters, sizes, etc., so that the surgeon does not need to assemble these at surgery. Accordingly, in one embodiment, a packaging for pre-packaged tethering components may be rated for various loads, for example, a number 1 package could maintain tensile loads of up to X newtons, and a number 2 package could maintain tensile loads of up to 2× newtons, etc. This would allow the surgeon to apply the correct type of tethering material after determining the necessary load, which is applied to multiple bony members for initial restoration of the desirable relationship therebetween, as explained herein below in regard to the inventive method.
Generally, the surgery for idiopathic scoliosis includes initial segmental derotation to correct segmental curvature by using compression or distractor instruments. The surgeon may elect to use traditional metal hook and screw systems to temporarily correct the spinal deformity while the tethering system is applied, and then remove the traditional hardware prior to closing the wound. An initial load may be determined by a compressor/distractor instrument that has a force gauge associated with it, such as a calibrated spring. The determined load, which is typically a tensile load, should be sufficient to dislocate bony members relative to one another so as to restore the desired curvature, shape or relationship therebetween and an intervertebral disc of a single motion segment or multiple motion segments.
Having restored the desirable relationship, the surgeon couples the inventive non-rigid system, which has predetermined physical qualities, to the loaded bony members. If the load is tensile, the corrective force generated by the inventive system is compressive and sufficient to maintain the desired load during a healing period upon removal of the compression/distraction instrument(s) or implant(s) used for the application of the desired load.
Any suitable fasteners 22 may be used to couple the tethering material 18 to the spine and may include screws 28 (
While the description mainly relates to a structure of flexible system, the scope of the invention encompasses its broad application. For example, one embodiment comprises a surgical kit comprising a plurality of components of the flexible system and may include a rigid fixing system. Accordingly, the kit may include one or more fasteners, fastener inserter(s), such as a driver, drill and the like, length(s) of tethering material, a compressor/distractor instrument that has a force gauge, such as a calibrated spring, and any other component, as disclosed within the scope of this invention.
Along with variously configured fasteners, attachment of the tethering material 18 to the spine 38 may be accomplished by a variety of techniques. For instance,
The tethering material 18 can be secured directly to variously shaped fasteners instead of relying on the interference between the fastener and the vertebral body. For example,
The flexibility of the inventive system 10 allows the fasteners to be selectively mounted to different posterior, anterior lateral and medial regions of the spine. For instance, as shown in
Alternatively, the bands can be looped around a fastener so that the segment(s) of the tethering material are further pulled back and attached to other vertebral segments in any convenient manner. For instance, the free end 70 of one of the tethering segments can be looped through the button 46 affixed to the side of the vertebrae opposite the entry point. Depending on the local requirements, the free end 70 can be knotted or otherwise secured the suture anchor 52 or to any of desired vertebral bodies of the spine 38 by the wedge 66. A variety of attachment arrangements is limitless subject only to a number and configuration of the fasteners and, of course, to the specifics of a given procedure.
This embodiment is also illustrative of a number of the segments constituting the tethering material 18. Thus, the end vertebrae 62, 64 each are connected to a respective inner vertebra, located immediately next to it, by, for example, a two-band tethering material, whereas the rest of the inner vertebrae, which would experience lower loads, can be interconnected by a single-band tethering material. Single fasteners can support multiple tethering segments.
Referring to
Any of the aforementioned fasteners may be used in conjunction with the tethering post. Alternatively, or additionally, the support plate 72 may have an inner side carrying a plurality of spikes 76 formed integrally with the element, as shown in
Another embodiment of the flexible system 10 is shown in
Note that any combination or pattern of the fasteners and posts can be utilized in combination with both plate-like element 72′ and support plate 72 to meet the specific surgical requirements of the patients. Thus, as illustrated in
Often times in order to correct severe scoliosis, the shape of the vertebral body itself may need to be corrected or restored to a more natural shape. For instance, sometimes the frontal profile of the vertebral body in scoliosis patients are wedge shaped 84 (
Alternatively, the deformity illustrated in
The added wedge 82 could be demineralized partially on the outer surfaces to enhance a fusion process and to impart a slight degree of flexibility, even if the juxtaposed surface of the end plate fuses to the adjacent vertebral bodies. Alternatively, the wedge can be completely demineralized. As shown in
Universality of the inventive system 10 as a corrective system and as a support for implants allows it to be a viable alternative to a rigid fixation system, which typically includes multiple pedicle screws, rods, hooks, anterior plates and/or anterior screws, or the two can be combined to supplement one another. Thus, when the deformation of a single spinal segment (vertebra-disc-vertebra) is severe enough to have the surgeon consider the use of the rigid fixation system, only for example, an apex of the curvature can be fused and corrected/derotated by means of the rigid system. The rest of the vertebral segments contributing to lesser extents to the deformed spinal curvature, located adjacent or spaced from the vertebral motion segment to be fused and stabilized via said rigid fixation systems, can be corrected/derotated via the flexible stabilization by the inventive tethering system 10, if needed. Note that the flexible tethering material 18 can be configured to have a selective number of intertwined lengths thereof to provide the desired thickness/strength of the material, which would be sufficient to generate various corrective loads as well to ensure the desired position of the implant.
Accordingly, any of the tethering systems described herein can be used as a stabilizer/barrier to expulsion for interbody fusion procedures that in addition to or as an alternative to the correction of deformities, may simply be used to restore disc height in order to relieve pain. In this case, the tethering system 10 would bridge the disc space preventing the expulsion of the implant therefrom while providing stability between the coupled vertebrae. Securement of the implant in the disc space can be significantly enhanced by providing the tethering system 10 with numerous lengths of the tethering material 18, which can be braided, netted, intertwined, interwoven, tied together, to form a reliable barrier capable of preventing the displacement of the implant.
To improve the structural strength of the tethering system 10, the added wedge 82 can have laterally extending arms 86 made integral to the tethering posts, as seen in
As seen in
The distracting system 94 may include variously configured shafts 98 made from pieces of cortical bone that may constitute either the entire shaft lengths of the system 94, or sections thereof. These sections may be sectioned parallel, perpendicular, or at an angle to the long axis of the cortical bone shaft. A structure of the shafts 98 is designed to facilitate the attachment of the shaft to a shaft supporting structure, which, depending on the location of any given shaft, may be any of the posterior elements of the vertebral body or previously tethering posts, such as 78. As shown in
Yet a further modification of the shafts 98 includes a plurality of intersecting grooves, as illustrated in
As with the fasteners, couplers, anchors, screws, etc., the shafts can be treated with substances to stimulate bony fusion as well as prevent infections. Additionally, the flexible members can be treated, coated, prepared with a substance or substances that will inhibit scar formation, fusion, or prevent infections. Phytochemical compounds have inhibitory effects on keloid fibroblasts (KF) and hypertrophic scar-derived fibroblasts (HSF). Compounds such as, hydroxybenzoics, flavonols [i.e. quercetin and kaempferol], and turmeric curcuminare are potential scar inhibitors. These hytochemicals inhibit fibroblast proliferation by inducing cell growth arrest but not apoptosis. The compounds quercetin, gallic acid, protocatechuic acid, and chlorogenic acid are the strongest inhibitors. Tamoxifin, 5-fluorouracil, matrix metalloproteinase inhibitors and TGF-Beta inhibitors can also reduce postoperative scarring. It has also been shown that the use of external irradiation, Agaricus bisporus (edible mushroom lectin), tetrandrine, and chitosan-polyvinyl pyrrolidone hydrogels may be effective scar inhibitors.
The inventive system may be used as a flexible, or non-flexible “bridge” between any of the posterior processes of two or more vertebrae. The system can be attached to the (posterior) spinous, transverse, mammillary, and articular processes as well as to the pedicles or the lamina using screws or snaps, or could even slip around several processes like a rubberband or a cap and then be secured with screw, pins or snaps. Such as bridge can be made of either bone or a compatible synthetic material, as disclosed above. It may be treated to prevent bone growth in the case where union is not desired. The bridge can alternatively enhance fusion to the spinous, transverse, mammillary, and articular processes as well as the pedicles or the lamina.
Another embodiment of the tethering system 10 may include a construct configured of a tethering material, which is formed naturally and integrally with the end bone segments shaved to have the desired shape and be used as fasteners. Compositionally, this system includes, for example, Bone-Tendon-Bone (BTB) portions of tissue.
As illustrated in
While each of the configurations of the tethering system 10 is illustrated as having uniformly shaped fasteners, the latter may have different shapes and cross sections. Thus, for example, at least one of the wedges can have a square cross section (
Also, instead of the fasteners, the transverse and/or posterior processes 118 can be used as tethering posts, either naturally, or by contouring them for supporting the tethering material 18 looped over the fasteners' outer ends. Any of the posterior elements such as pedicles and any of costal, mammilary, accessory, inferior, superior processes and spinal processes, as shown in
Still a further embodiment of the tethering system 10 includes only a bone structure, which has selectively demineralized portions serving as a flexible tethering material, which is capable of supporting tensile loads. In particular, consecutive portions of the bone may be selectively (segmentally) demineralized (SDB) to provide at least one intermediary flexible portion, whereas the respective end portions remain mineralized and serve as fasteners, which can feature any desired shape. While the length of the demineralized intermediary portion can vary, it may be advantageous to demineralize about ⅓ of the entire length. As can be readily understood, all disclosed embodiments of the inventive tethering system 10, including the bone-tendon-bone (BTB) and segmentally demineralized bone (SDB), can be used to join adjacent or non-adjacent motion segments. Alternatively, such a bone segment can be segmentally demineralized in multiple places, which would advantageously be used to span multiple vertebral motion segments.
Vertebral bodies 120 can have channels or tunnels 122 (
A method of affixing any of the described tethering systems 10, including but not limited to the bone-tendon-bone (BTB) or sequentially demineralized bone (SDB), is illustrated in
It will be understood that various modifications may be made to the embodiments disclosed herein. Furthermore, the inventive tethering system, described primarily in the context of the spine curvatures, can be equally effective in treating any other bony motion segment including two or more relatively displaceable portions. Therefore, the above description should not be construed as limiting, but merely as exemplifications of preferred embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the claims appended hereto.
This application is a continuation of International Patent Application No. PCT/US2004/034243, filed on Oct. 15, 2004, which claims priority to U.S. Provisional Application No. 60/511,807, filed on Oct. 16, 2003, the contents of which are incorporated in their entirety by reference herein.
Number | Date | Country | |
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60511807 | Oct 2003 | US |
Number | Date | Country | |
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Parent | PCT/US04/34243 | Oct 2004 | US |
Child | 11404587 | Apr 2006 | US |