Devices, systems, and methods to fixate tissue within the regions of body, such as the pharyngeal conduit
Systems and methods incorporate implant structures, and/or implantation devices, and/or surgical implantation techniques, to make possible the treatment of physiologic conditions, such as sleep disordered breathing, with enhanced effectiveness.
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This application claims the benefit of U.S. patent application Ser. No. 10/718,254, filed Nov. 20, 2003 and entitled “Devices, Systems, and Methods to Fixate Tissue Within the Regions of the Body, Such as the Pharyngeal Conduit”; U.S. patent application Ser. No. 10/656,861, filed Sep. 6, 2003 and entitled “Magnetic Force Devices, Systems, and Methods for Resisting Tissue Collapse within the Pharaygeal Conduit”; U.S. patent application Ser. No. 10/236,455, filed Sep. 6, 2002 and entitled “Systems and Methods for Moving and/or Restraining Tissue in the Upper Respiratory System”; and U.S. Provisional Patent Application Ser. No. 60/441,639, filed Jan. 22, 2003 and entitled “Magnetic Splint Device and Method for the Treatment of Upper Airway Collapse in Obstructive Sleep Apnea;” and U.S. Provisional Patent Application Ser. No. 60/456,164, filed Mar. 20, 2003 and entitled “Device and Method for Treatment of Sleep Related Breathing Disorders Including Snoring and Sleep Apnea,” which are each incorporated herein by reference.
FIELD OF THE INVENTIONThe invention is directed to devices, systems, and methods that fixate or brace tissue in targeted body regions, e.g., in the pharyngeal conduit for the treatment of sleep disordered breathing including obstructive sleep apnea.
BACKGROUND OF THE INVENTIONI. THE CHARACTERISTICS OF SLEEP APNEA
First described in 1965, sleep apnea is a breathing disorder characterized by brief interruptions (10 seconds or more) of breathing during sleep. Sleep apnea is a common but serious, potentially life-threatening condition, affecting as many as 18 million Ameritans.
There are two types of sleep apnea: central and obstructive. Central sleep apnea, which is relatively rare, occurs when the brain fails to send the -appropriate signal to the breathing muscles to initiate respirations, e.g., as a result of brain stem injury or damage. Mechanical ventilation is the only treatment available to ensure continued breathing.
Obstructive sleep apnea (OSA) is far more common. It is one of the several entities that make up the broader group of sleep disordered breathing (SDB). This group of disorders ranges from habitual snoring to OSA. Normally, the muscles of the upper part of the throat keep the airway open to permit air flow into the lungs. When the muscles of the upper airway relax and sag, the relaxed. tissues may vibrate as air flows past the tissues during breathing, resulting in snoring. Snoring affects about half of men and 25 percent of women—most of whom are age 50 or older.
In more serious cases, the airway becomes blocked, making breathing labored and noisy, or even stopping it altogether. In a given night, the number of involuntary breathing pauses or “apneic events” can be quite frequent. These breathing pauses are almost always accompanied by snoring between apnea episodes, although not everyone who snores has OSA.
Lack of air intake into the lungs results in lower levels of oxygen and increased levels of carbon dioxide in the blood. The altered levels of oxygen and carbon dioxide alert the brain to resume breathing and cause arousal. The frequent interruptions of deep, restorative sleep often lead to early morning headaches, excessive daytime sleepiness, depression, irritability, and learning and memory difficulties.
The medical community has become aware of the increased incidence of heart attacks, hypertension and strokes in people with moderate or severe obstructive sleep apnea. It is estimated that up to 50 percent of sleep apnea patients have high blood pressure.
Upon an apneic event, the sleeping person is unable to continue normal respiratory function and the level of oxygen saturation in the blood is reduced. The brain will sense the condition and cause the sleeper to struggle and gasp for air. Breathing will then resume, often followed by continued apneic events. There are potentially damaging effects to the heart and blood vessels due to abrupt compensatory swings in blood pressure. Upon each event, the sleeping person will be partially aroused from sleep, resulting in a greatly reduced quality of sleep and associated daytime fatigue.
Although some apneic events are normal in all humans, the frequency of blockages will determine the seriousness of the disease and opportunity for health damage. When the incidence of blockage is frequent, corrective action should be taken.
II. SLEEP AND THE ANATOMY OF THE UPPER AIRWAY
As
The cross sectional area of the upper airway varies with the phases of the respiratory cycle. At the initiation of inspiration (Phase I), the airway begins to dilate and then to remain relatively constant through the remainder of inspiration (Phase II). At the onset of expiration (Phase III) the airway begins to enlarge, reaching maximum diameter and then diminishing in size so that at the end of expiration (Phase IV), it is at its narrowest, corresponding to the time when the upper airway dilator muscles are least active, and positive intraluminal pressure is lowest. The upper airway, therefore, has the greatest potential for collapse and closure at end-expiration. Schwab R J, Goldberg A N. Upper Airway Assessment: Radiographic and other Imaging Techniques. Otolaryngol Clin North Am 1998; 31:931-968.
Sleep is characterized by a reduction in upper airway dilator muscle activity. For the individual with obstructive sleep apnea (OSA) and perhaps the other disorders which comprise much of the group of entities called obstructive sleep-disordered breathing (SDB), it is believed that this change in muscle function causes pharyngeal narrowing and collapse. Two possible etiologies for this phenomenon in OSA patients have been theorized. One is that these individuals reduce the airway dilator muscle tone more than non-apneics during sleep (the neural theory). The other is that all individuals experience the same reduction in dilator activity in sleep, but that the apneic has a pharynx that is structurally less stable (the anatomic theory). Both theories may in fact be contributors to OSA, but current studies seem to support that OSA patients have an intrinsically structurally narrowed and more collapsible pharynx. Isono S. Remmers J, Tanaka A Sho Y, Sato J, Nishino T. Anatomy of Pharynx in Patients with Obstructive Sleep Apnea and in Normal Subjects. J Appl Physiol 1997: 82:1319-1326.
Although anatomic closure is often accentuated at specific sites, such as the velopharyngeal level [Isono, Ibid], studies of closing pressures [Isono, Ibid] supports dynamic fast MRI imaging that shows narrowing and collapse usually occurs along the entire length of the pharynx. Shellock F G, Schatz C J, Julien P, Silverman J M, Steinberg F, Foo T K F, Hopp M L, Westbrook P R. Occlusion and Narrowing of the Pharyngeal Airway in Obstructive Sleep Apnea: Evaluation by Ultrafast Spoiled GRASS MR Imaging. Am J of Roentgenology 1992:158:1019-1024.
III. PRIOR TREATMENT MODALITIES
To date, the only modality that addresses collapse along the entire upper airway is mechanical positive pressure breathing devices, such as continuous positive airway pressure (CPAP) machines. All other modalities, such as various surgical procedures and oral appliances, by their nature, address specific sectors of the airway (such as palate, tongue base and hyoid-vallecula levels), but leave portions of pharyngeal wall untreated. This may account for the considerably higher success rate of CPAP over surgery and appliances in controlling OSA. Although CPAP, which in essence acts as an airway splint for the respiratory cycle, is highly successful, it has some very significant shortcomings. It can be cumbersome to wear and travel with, difficult to accept on a social level, and not tolerated by many (for reasons such as claustrophobia, facial and nasal mask pressure sores, airway irritation). These factors have lead to a relatively poor long-term compliance rate. One study has shown that 65% of patients abandon their CPAP treatment in 6 months.
The need remains for simple, cost-effective devices, systems, and methods for reducing or preventing sleep disordered breathing events.
SUMMARY OF THE INVENTIONOne aspect of the invention provides systems and methods that include implant structures, and/or implantation devices, and/or surgical implantation techniques, which make possible the treatment of physiologic conditions with enhanced effectiveness.
In one embodiment, then systems and methods provide treatment for dysfunctions affecting the pharyngeal conduit, such as sleep disordered breathing, snoring, or sleep apnea. The systems and methods provide an implant that is sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit. The systems and methods also provide at least one tool and/or instructions for placing the implant 206 in a tissue region, e.g., through a percutaneous access path; or by forming a surgical flap; or by forming a surgical pocket. The systems and methods can also include providing at least one tool and/or instructions for stabilizing the implant within a mucosa, or a submucosa, or against a fascia, or against or within a muscle; or, alternatively, the tool and/or instructions can make possible the stabilization of the implant against a submucosa, or a fascia, or against or within a muscle, without stabilizing through a mucosa. The systems and methods can include other tools and instructions, e.g., to make various mechanical fixation materials for the implant accessible; or to make agents that stimulate rapid fibrosis in the implantation site available; or to provide antibiotic materials for the implantation site. The systems and methods can comprise the components individually or as an assembled kit. The various instructions can be in written form, electronic form, or verbal form, which can be provided in the kit and/or as part of a training program or web site for clinicians.
The systems and methods can be used to treat airway collapse and increased airway resistance associated with the entire spectrum of obstructive sleep-disordered breathing. The systems and methods can also be used to lend upper airway support in neurological associated dystonic disorders.
Another aspect of the invention provides a polymer-bonded magnetic implant. The implant comprises a biocompatible polymer matrix sized and configured to be implanted in animal tissue. Magnetic particles are bound with the biocompatible polymer matrix. The magnetic particles are magnetized to possess a desired polarity. The magnetic particles can form regions of different particle densities within the biocompatible polymer matrix, or the magnetic particles can comprise an essentially uniform particle density within the biocompatible polymer matrix.
In one embodiment, at least one other magnet structure is encapsulated within the biocompatible polymer matrix with the magnetic particles. The other magnet can comprise a discrete permanent magnet, or a polymer-bonded magnet.
Another aspect of the invention provides a focused magnetic implant. The implant comprises a structure sized and configured to be implanted in animal tissue. The structure including at least one magnet made from a hard ferromagnetic material and a flux shield comprising a soft ferromagnetic material overlaying at least a portion of the magnet. The flux shield focuses and enhances the magnetic field of the magnet in directions that the shield does not overlay.
Another aspect of the invention provides a stablized magnetic implant. The implant comprising a structure sized and configured to be implanted in animal tissue. The structure includes at least one magnet made from a hard ferromagnetic material having a desired magnetic pole. At least one stabilization magnet is provided having a magnetic pole that is the same as the desired magnetic pole and that is oriented normal or at an acute angle to the desired magnetic pole. Should rotational misalignment of the implant relative to another magnetic implant occur, the presence of the stabilizing magnet keeps the magnetic field forces aligned. As a result, destabilizing magnetic fields are reduced due to misalignment.
Other features and advantages of the invention shall be apparent based upon the accompanying description, drawings, and claims.
DESCRIPTION OF THE DRAWINGS
FIGS. 18D(1) and 18D(2) are perspective front views of an alternative embodiments of stabilized magnetic structures that can be used in the magnetic force system shown in
Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.
I. MAGNETIC FORCE SYSTEMS TO FIXATE OR BRACE TISSUE
A. Overview
In the particular embodiment illustrated (see FIG. 2), the magnet force system 10 includes one or more ferromagnetic structures 12 implanted in the pharyngeal wall and/or one or more ferromagnetic structures 14 implanted in the posterior of the tongue. Both ferromagnetic structures 12 and 14 comprise at least one permanent magnet. Examples of known permanent magnet materials include alloys of Neodymium-Iron-Boron (NdFeB), alloys of Aluminum-Nickel-Cobalt (AlNiCo), and Samarium Cobalt (SmCo). The permanent magnets can be magnetized through the thickness in a variety of modes, such as multipole faces, radial homopolar, axial, or diametrical.
The permanent magnets in the opposing structures 12 and 14 possess the same magnetic orientation (North-North or South-South). According to physical laws, poles of like polarity repel each other with a magnetic force. The force of magnetic repulsion depends on the strength of the magnets and the distance between the poles.
The repelling force between the opposing tongue magnet(s) and pharyngeal wall magnet(s) is selected to be of a strength sufficient to remodel native tissue conditions within the airway. The repelling force alters existing morphology and/or motility and/or shape of tissue that, if not altered, could lead to tissue collapse, particularly during the respiratory cycle. The implanted ferromagnetic structures 12 and 14 establish tissue conditions that fixate or brace the tissue, to resist collapse along the pharyngeal conduit when imminent, i.e., during sleep, but without significantly stiffening the native tissue at times when tissue collapse is not imminent.
The orientation of the structures 12 and 14 can vary. The structures 12 and 14 may be oriented within tissue horizontally (as shown in
It should be appreciated that one of the structures 12 and 14 can be located external of the pharyngeal conduit, to magnetically interact with a structure implanted within the pharyngeal conduit. The magnetic force field created may be attracting and/or repelling, depending upon the anatomic orientation of the structures and the physiologic outcome desired. Various embodiments of magnetic force systems using implanted and/or external magnetic structures are shown in U.S. patent application Ser. No. 10/656,861, filed Sep. 6, 2003 and entitled “Magnetic Force Devices, Systems, and Methods for Resisting Tissue Collapse within the Pharaygeal Conduit,” which is incorporated hereby by reference.
The system 10 can be used to treat airway collapse and increased airway resistance associated with the entire spectrum of obstructive sleep-disordered breathing. The system 10 can also be used to lend upper airway support in neurological associated dystonic disorders. The system 10 can also be used in other regions of the body where tissue remodeling and/or bracing is indicated.
The fixation or bracing function of the implanted structures 12 and 14 impart improved comfort, tolerance, and bio-acceptance to the implanted structures 12 and 14 for the patient. The fixation or bracing function is achieved without indiscriminate dampening (i.e., stiffening) the spring constant of native tissue in the pharyngeal conduit (which is not desirable). The fixation or bracing function is achieved due to the controlled application of static and/or kinetic forces that push or pull on tissue, without themselves imparting stiffness to the tissue in the pharyngeal conduit. The size and configuration of the implanted structures are selected with the ease and bio-comfort of implantation in mind, while at the same time providing sufficient static and/or kinetic forces to resist tissue collapse when collapse is imminent, taking into account the anatomy of the region of implantation and orientation of other components of the system 10. The implanted structures 12 and 14 thereby provide conformability, tolerance, and comfort for the patient, without significantly dampening the spring constant of native tissue.
B. Magnetic Arrays
The implanted ferromagnetic structures 12 and/or 14 can each comprise a single or discrete source of magnetism having a given desired orientation. For example, a single permanent magnet, comprising a body of a ferromagnetic material, can comprise a single source of magnetism having a given orientation.
A given implanted ferromagnetic structure 12/14 of whatever form or configuration can be coated, plated, encapsulated, or deposited with a selected protective material 68 (see
The protective material 68 may also incorporate anticoagulants and/or antibiotics, be antimicrobial in nature, or be treated to create an antimicrobial surface.
1. Discrete Permanent Magnets on a Flexible Carrier
As shown in
The material of the carrier 18 can enclose the magnets 16, or the magnets 16 can be carried on the surface of the carrier 18. The spacing between the magnets 16 on or within the carrier 18 provides the requisite flexibility desired. The individual magnets 16 can have various geometries—rectangular, cylindrical, spherical, oval, etc.—as long as the desired physiologic response is achieved.
Further details of flexible magnetic arrays of the type described can be found in copending U.S. patent application Ser. No. 10/236,455, filed Sep. 6, 2002 and entitled “Systems and Methods for Moving and/or Restraining Tissue in the Upper Respiratory System,” which is incorporated herein by reference.
2. Polymer-Bonded Magnetic Structures
The magnetic structures 12 and/or 14 can include one or more polymer-bonded magnets 20, as shown in
To form the polymer-bonded magnet 20, the magnetic particles 22 are compounded with the biocompatible polymer 24 in a desired proportion. The proportion of polymer 24 and magnetic particles 22 in the magnet 20 can be tailored to provide a desired degree of flexibility, elasticity, and magnetic strength.
The biocompatible polymer 24 is mixed with magnetic particles 22 in a predetermined ratio, and the mixture is compounded (i.e., kneaded). After compounding, the mixture can be molded into a desired shape. The molding methods can include, e.g., injection molding, compression molding, extrusion, and calendering.
Following molding, the molded component can be cut or machined as needed. Secondary surface coating using other biocompatible polymers may be applied, if desired. Alternatively, or in combination, two-stage molding may be accomplished, during which the molded component is over-molded with a layer of biocompatible polymer.
The finished component is then magnetized to possess the desired polarity. The polymer-bonded magnet 20 is thereby formed as a single piece, which reduces flux leakage.
In the system 10 shown in
Finite element analysis shows that two repelling polymer-bonded magnets 20, each formed as a strip measuring 4 mm×10 mm×40 mm, are capable of creating a maximum energy product of about 0.8 MGOe. Finite element analysis based upon this energy product shows that the two polymer-bonded magnets 20 can generate a repelling force of more than 22 grams/cm2 when they are positioned 12 mm apart. The magnetic properties of the strips and their dimensions can, of course, be changed to fit the applications.
The shape of a given polymer-bonded magnet 20 can be selected to best confirm to the anatomic site of implantation. It is believed that the biocompatibility, softness, and flexibility of a polymer-bonded magnet 20 make it tolerable during chronic implantation in tissue. Larger sizes of a given magnetic structure could also be considered, compared to use of conventional permanent magnets, because the similar mechanical properties of the polymer-bonded magnet 20 and the surrounding tissue.
The polymer-bonded magnet 20 can include through holes, and/or non-through holes, and/or complex surface configurations, and/or other surface textures, or combinations thereof, to promote tissue in-growth and implant stability. Further discussion of tissue ingrowth surfaces and materials follows.
3. Hybrid Magnetic Structures
The magnetic structures 12 and/or 14 may include a hybrid magnetic structure 26, as shown in
The permanent magnets 28 can comprise sintered, high energy, permanent magnets such as N45 or N48, i.e., possessing a maximum energy product of about 45-48 MGOe. If desired (as shown in
As previously described, the magnetic particles 22 can comprise either isotropic or anisotropic materials, e.g., NdFeB, SmCo, ferrite and/or alnico particles. The biocompatible polymer 24 can comprise, e.g., polycarbonate, silicone rubber, polyurethane, silicon elastomer, or a flexible or semi-rigid plastic. Fabric and/or textile and/or ceramic material can also be incorporated within the polymer matrix. Within the structure 26, the permanent magnets 28 and the magnetic particles 22 are magnetized in the same flux direction.
The hybrid structure 26 takes advantage of the high magnetic strength of the sintered permanent magnets 28, and combines this benefit with the flexibility and biocompatibility of a polymer-bonded magnetic matrix 30. Furthermore, the presence of the permanent magnetic particles 22 between the high energy permanent magnets 28 pushes the flux lines emanating from the permanent magnets 28 farther away from the surface of the structure 26, as compared to permanent magnets 28 in a pure (non-magnetic) polymer matrix. This change in the flux lines reduces flux leakage.
The density of magnetic particles 22 in the magnets 20 is desirably greater than the density of magnetic particles 22 in the matrix 30. This imparts more flexibility to the low-density matrix 30 and higher magnetic force to the higher density magnets 20. If desired (as shown in
As previously described, the magnetic particles 22 can comprise either isotropic or anisotropic materials, e.g., NdFeB, SmCo, ferrite and/or alnico particles; and the biocompatible polymer 24 can comprise, e.g., polycarbonate, silicone rubber, polyurethane, silicon elastomer, or a flexible or semi-rigid plastic. Fabric and/or textile and/or ceramic material can also be incorporated within the polymer matrix. Within the structure 32, the magnetic particles 22 in the magnets 20 and in the matrix 30 are magnetized in the same flux direction.
The hybrid structure 32 takes advantage of the high density, high performance polymer-bonded magnets 20, and combines this benefit with the flexibility of the low-density polymer-bonded magnetic matrix 30. Furthermore, as described in connection with the hybrid structure 32 in
In the system 10 shown in
The shape of a given hybrid magnetic structure 26 or 32 can be selected to best confirm to the anatomic site of implantation. Furthermore, either hybrid magnetic structure 26 or 32 can include through holes 36 (see
4. Layered Magnetic Structures
The magnetic structures 12 and/or 14 could include a layered magnetic structure 40, as shown in
The density of magnetic particles 22 in layers L1, L3, and L5 is greater than the density of magnetic particles 22 in the neighboring layers L2, L4, and L6. The presence of the less dense layers L2, L4, and L6 imparts overall flexibility to structure 40, whereas the presence of the more dense layers L1, L3, and L5 imparts higher magnetic force. The juxtaposition of the less dense layers L2, L4, and L6 between the more dense layers L1, L3, and L5 pushes the flux lines emanating from the higher density layers L1, L3, and L5 farther away from the surface of the structure 40, as compared to uniform density polymer-bonded magnetic layers. This change in the flux lines reduces flux leakage.
As previously described, the magnetic particles 22 can comprise either isotropic or anisotropic materials, e.g., NdFeB, SmCo, ferrite and/or alnico particles; and the biocompatible polymer 24 can comprise, e.g., polycarbonate, silicone rubber, polyurethane, silicon elastomer, or a flexible or semi-rigid plastic. Fabric and/or textile and/or ceramic material can also be incorporated within the polymer matrix. Within the structure 40, the magnetic particles 22 in the layers L1 to L6 are magnetized in the same flux direction.
In
In the system 10 shown in
The shape of a layered magnetic structure 40 can be selected to best confirm to the anatomic site of implantation. For example, as shown in
As
C. Focusing the Magnetic Flux of Magnetic Structures
Regardless of the type of magnetic structure that is implanted, it is desirable to achieve high repelling forces using an array of magnets of relatively small size, which can be tolerated by the body without discomfort. A way to achieve this objective is to include means for focusing the magnetic flux in a desired direction, while also reducing the flux in other directions. The focusing of magnetic flux can make possible the use of smaller magnets. The focusing of magnetic flux can also impart stability to the implanted structure, to resist migration within tissue.
As the following examples demonstrate, the presence of a flux shield 50 of a soft ferromagnetic material focuses and enhances the magnetic field of the core 48 in directions that the shield 50 does not overlay. In
A comparison of FIGS. 14B/C with FIGS. 15B/C demonstrates the ability of a soft ferromagnetic material to shield and to focus the magnetic field emanating from a permanent magnet.
EXAMPLE 3 Alternative Shielded Magnets
D. Reducing Instability of the Magnetic Structures
Regardless of the type of magnetic structure that is implanted, it is also desirable to minimize the effects of instability due to magnetic field forces. It is also desirable to minimize migration or twisting should misalignment between the magnetic field forces of opposed magnetic structures 12 and 14 occur. If repelling like poles become misaligned, unlike poles may seek to attract and align.
A way to minimize the effects of instability is to include stabilization magnets having repelling poles normal or at an acute angle to the major repelling pole. By way of illustration,
The magnetic core 54 can comprise a rare earth permanent magnet, or a polymer-bonded magnet, or a hybrid magnetic structure, or a layered magnetic structure, all having previously been described. The magnetic core 54 has a repelling pole 58 that is sized and configured to be primarily responsible for the repelling force needed for a given structure.
Each stabilizing magnet 56 is secured to a side of the repelling magnetic core 54, e.g., by adhesive, welding, molding, crimping, or soldering. The stabilizing magnets 56 comprise rare earth permanent magnets, or a polymer-bonded magnet, or a hybrid magnetic structure, or a layered magnetic structure, all having previously been described. The stabilizing magnets 56 each has a repelling pole 60 (i.e., having the same polarity as the repelling pole 58). The surfaces of the repelling poles 60 of the stabilizing magnets 56 are oriented at right angles to the repelling pole 58 of the magnetic core 52. The poles 60 of the permanent stabilizing magnets 56, like the repelling pole 58 of the magnetic core 52, are all like the poles of the magnet(s) on the opposing magnetic structure.
Should rotational misalignment of one magnetic structure occur, the outward facing poles 60 of the permanent stabilizing magnets 56 will, to a greater or lesser degree, continue to face the like poles of the magnet(s) on the other magnetic structure. Since the outward facing poles 60 of the permanent stabilizing magnets 56 are like the poles of the other structure, the repelling nature of magnetic field between the two structures remains the same—the two magnet structures 12 and 14 continue to repel each other. Rotational misalignment may lead to a diminution of the magnetic force field, but the magnetic force field is itself still a repelling field. Destabilizing magnetic fields are reduced due to misalignment, to reduce twisting or otherwise destabilizing either structure 12/14.
As further shown in
In a representative embodiment, the repelling magnetic core 54 has a dimension of 2 mm×2 mm×4 mm. Each stabilizing magnet 56 has a dimension of 1 mm×2 mm×4 mm. The shielding pole piece 62 has a dimension of 4 mm×4 mm×0.5 mm. The resulting structures 52 can be assembled into arrays 64 of stabilized magnetic structures 52 (see
As
Positional stability of a given array of magnets can also be enhanced without use of stabilizing magnets 56. As shown in FIGS. 18D(1) and 18D(2), and as previously described, magnetic cores 54 (comprising e.g., rare earth permanent magnets, or polymer-bonded magnets, or hybrid magnetic structures, or layered magnetic structures) can be arranged along a flexible carrier C. Each magnetic core 54 has a repelling pole 58 that is sized and configured for the repelling force needed for a given structure. Enhanced positional stability in such an array can be achieved by reorienting a repelling pole 58 of one of the magnetic cores 54 by ninety-degrees, in either direction (shown, respectively, in FIGS. 18D(1) and 18D(2) relative to the orientation of its neighboring cores 54. Within a given array, one or more cores 54 can be reoriented in this manner in either a random or repeating pattern. Should rotational misalignment of one magnetic array relative to another magnetic array occur, the presence of at least one reoriented core within one or both of the arrays will, to a greater or lesser degree, maintain the repelling nature of magnetic field between the two structures. Destabilizing magnetic fields are reduced due to misalignment, to reduce twisting or otherwise destabilizing either array.
II. FIXATION OF STRUCTURES IMPLANTED IN TISSUE
Implants of the types described herein, or of other designs and functions, can be fixed percutaneously into the pharyngeal wall and/or tongue (the locations shown in
A. Use of Mechanical Fixation Materials
The position of implanted magnetic structures 12/14 or any implant in general can be fixed against migration in a targeted tissue region, e.g., within the pharyngeal conduit, using conventional mechanical fixation materials and techniques known in the surgical arts, e.g., resorbable or non-resorbable sutures, screws, staples, darts, clips, adhesives, or glues such as cyanoacrylate, or cements such as polymethyl methacrylate (PMMA) cement. For example, the structures 12/14 or any implant in general can include preformed apertures to accommodate the fixation material, i.e., sutures, screws, staples, darts, or clips. Fixation to tissue enhances the fixation function of the implanted structure.
The tissue to which a given implant is fixed can include soft tissue, such as mucosa, submucosa, fascia, or muscle in the pharyngeal walls, the base of the tongue; the vallecula; the soft palate with uvula; the palatine tonsils with associated pillar tissue, and the epiglottis.
The tissue can also include bone within the pharyngeal conduit, e.g., a hyoid bone or a vertebra.
Various systems for mechanically securing implanted magnetic structures in tissue, muscle, or bone are shown in U.S. patent application Ser. No. 10/718,254, filed Nov. 20, 2003 and entitled “Devices, Systems, and Methods to Fixate Tissue Within the Regions of the Body, Such as the Pharyngeal Conduit,” which is incorporated herein by reference.
A given magnetic structure or implant can implanted in either a horizontal or vertical anatomic orientation, and/or in a linear or curvilinear pattern within the pharyngeal conduit or elsewhere in the body.
B. Fixation in Muscle or Other Soft Tissue
1. Direct Approach (The Flap)
Implants can be placed directly within the mucosa, or the submucosa, or against the fascia, or against or within muscle within the pharyngeal wall and/or tongue (the locations shown in
Using a flap approach, no sutures need to be placed through the mucosa into the implant. It has been discovered that placement of sutures through the mucosa can provide a conduit effect along the suture line from the contaminated oral cavity into the sterile implant pocket. Also, when using a flap approach, the implant can be better stabilized under direct vision, so the implant can be better positioned, since visualization is direct.
The flap approach can be accomplished in a single stage or in two stages. Either approach can be used to place a magnetic structure or any other type or style of implant in the pharyngeal conduit or elsewhere in the body.
a. Single Stage Flap Approach
After transoral exposure of the oral cavity, lateral wall or tongue, a flap 70 is formed in the tissue plane (see
Elevating a flap 70 can expose underlying muscle 72 (see
As
It should be appreciated that, instead of forming a flap, a surgical pocket can be formed to receive the implant. The pocket is formed by dilating tissue by use of a trocar or expandable dissector, to open a tissue space to receive an implant. Using a pocket approach, like the flap approach, no sutures need to be placed through the mucosa into the implant. The implantation and implant fixation techniques described herein with regard a surgical flap apply to surgical pockets as well.
As
Agents to stimulate rapid fibrosis can be used for further stabilization. Examples of such agents include fibrin sealants, tissue sealants, talc (dry or slurry), doxycycline, bleornycin, povidone iodine, minocycline, doxorubicin, streptokinase, urokinase, sodium tetradecyl sulfate, and/or silver nitrate. Other coatings to promote the stability of the implant 74 include calcium hydroxylapatite, aluminum oxide, bioactive hydroxyl apatite, or tricalcium phosphate. Such agents can be applied only at pre-selected locations on the implant 74, e.g., such as bottom and side boundaries, to leave easy access to the top portion of the implant 74 for removal. Alternatively, such agents can be injected directly into the flap 70 (or pocket), or may used to irrigate the flap 70 (or pocket), or may be placed within a gel or hydrogel in the flap 70 (or pocket).
Tissue adhesives, fibrin sealants, and glues such as cyanoacrylate, or cements such as polymethyl methacrylate (PMMA) cement can be applied to either improve stabilization or replace mechanical sutures or fasteners. A tissue ablation agent or energy source may be used to form avascular pockets.
Tissue ingrowth materials can also be used, as will be described in greater detail later.
b. Two Stage Flap Approach
The techniques described above can also be done in a two stage manner.
In this arrangement (see
A modular receptacle 82 or sleeve (see
As
After the receptacle 82 has been allowed to stabilize within the flap 70 (or pocket), a selected implant 74 is loaded into the receptacle 82 (see
The two stage approach allows stabilization of a basic implant support (i.e., the receptacle 82) to occur within a flap or pocket prior to the introduction of the operative implant 74, e.g., one subject to magnetic forces or another potentially destabilizing force. The two stage approach also allows one to titrate, e.g., magnetic force requirements to the individual patient's needs without replacing the basic implant support.
C. Instrument Approaches
Implants of the types described herein, or of other designs and functions, can also be placed percutaneously into the pharyngeal wall and/or tongue (the locations shown in
Alternatively, the dissector 88 and access cannula 86 can be deployed nested together, being passed as a unit into tissue, with or without use of a guide wire. The blunt tip of the dissector 88 projects beyond the distal end of the cannula 86, serving to open an entry site and separate the tissue layers at the implantation site. The dissector 88 can then be removed from the cannula 86, to open the working channel.
In either embodiment, another instrument may be deployed through the working channel of the cannula 86, if necessary, to create a surgical pocket in the tissues to receive the implant.
As
Alternatively, the implant 94 can be loaded directly into the proximal end of the cannula 86, and the plunger 96 passed through the cannula 86 to advance the implant to the distal tip of the cannula 86. Holding the plunger stationary and pulling back on the cannula 86 expels the implant into the prepared implantation site. The cannula 86 and plunger 96 can then removed as a unit, leaving the implant behind.
As
In
For example, in this arrangement (see
As shown in
Once deployed, the implant 94 may or may not be further anchored to the underlying tissues/muscle layer. Within the implantation site, the position of the implant 94 may be stabilized using a suitable stabilization element, e.g., one or more staples, and/or clips, and/or darts, and/or sutures, and/or medical adhesives or glues, as previously described. Stablization can be achieved without fixation of the implant to mucosa or submucosa tissue, if desired. Tools that place the stabilizing element in the implant 94 may be an integrated part of the access cannula or implant delivery tool, or may comprise one or more separate tools that are themselves deployed through the working channel of the cannula 86, or may comprise one or more tools that are deployed by some other means.
The working channel of the cannula 86 can also be used to flush the delivery site with antibiotic solutions prior to, during, and after implant delivery. The antibiotic solutions can include, e.g., chlorohexalin, kanamicin, Baytril, cephalexin, or gentamicin.
The cannula and other tools of the system can be made of metal, plastic, or ceramic materials, or combinations thereof. The cannula and other tools can be made of flexible materials, allowing the instruments to be flexed or shaped during use (as
As shown in
The elastic arms 102 and 104 are placed into compression and bent inward toward the implant 94, into what can be called an inboard condition, when the implant 24 is confined within the delivery tool 92 (see
In this arrangement (see
The implant 92 is loaded into the tool 92, trailing edge first, with the elastic arms 102 and 104 in their outboard condition. The slots 106 accommodate passage of the elastic arms 102 on the trailing edge of the implant 92, as the implant is progressively loaded into the tool 92. As
At time of deployment, the plunger 96 is held stationary, and the tool 92 is drawn away from the implantation site. This will release the implant 92 from the confines of the tool 92, leading edge first. As the leading edge of the implant clears the tool 92, the arms 104 will spring outward to their outboard condition (see
Other systems and devices may be used to deliver an implant to an implantation site in the pharyngeal conduit or elsewhere in the body. For example,
A plunger 118 abuts against the trailing edge of the implant 94. The plunger 118 is coupled by a push-pull cable (which passes through the tubing 116) to an actuator 120 on the handle 114. Pushing forward on the actuator 120 advances the plunger 118 (see
In the alternative embodiment shown in
D. Tissue In-Growth Surfaces
In addition to any of the just-described tissue fixation methodologies, a given implant can include a tissue in-growth surface 70 (see
In general, the surface 70 provides an environment that encourages the in-growth of neighboring tissue on the implanted structure. Tissue in-growth is defined as the filing of pores in an implanted material with cellular material. As in-growth occurs, the implanted structure 12 will become securely anchored, resisting migration or extrusion from the tissue. The tissue in-growth surface 70 thus enhances tissue adhesion and stabilization, and thereby further stabilizes and fixes the position of the implanted structure 12 in the targeted implantation site.
The tissue in-growth surface 70 can be formed in various ways, such as the porous nature of the material, knitting, weaving, through holes, or molding a porous structure or surface. Examples of suitable materials include polytetrafluoroethylene (PTFE), expanded PTFE, polyethylene terephthalate such as Dacron® (PET) fabric, other permanent polyesters, polyurethane, silicone, polypropylenepolyvinyl alcohol, biodegradeable polyesters such as polylactic acid and polyglycolic acid.
It may be desirable to mechanically anchor the implanted magnetic structures while allowing in-growth to occur. Anchoring may be accomplished by use of resorbable or non-resorbable sutures, screws or other mechanical fasteners made of resorbable or non-resorbable materials such as polyglycolic acid or other similar compounds. Tissue adhesives and/or tissue cements such as PMMA and/or tissue sealants, and/or tissue glue such as cyanacrylate may also be used to provide tissue adhesion, fixation, and stabilization.
Complete tissue in-growth is determined by the percentage of the material that has been infiltrated by the cellular material. With pore sizes from 100 micrometers to 500 micrometers, blood vessels can be formed. With pore sizes of 10 micrometers to 100 micrometers, cells to small capillaries can form.
Also, materials or shapes may be used that encourage tissue or fibrotic encapsulation of the implant 94, with or without tissue ingrowth.
III. SYSTEMS FOR PROVIDING TREATMENT
It is apparent from the foregoing that various systems can be created, based upon the above-described implant structures, implantation devices, and surgical implantation techniques, to make it possible for healthcare providers to treat physiologic conditions with enhanced effectiveness.
For example, as shown in
The implant component 202 can include providing one or more implants 206 that are sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit. Several embodiments of implants 206 having this characteristic have been described herein. Other representative embodiments are described in U.S. patent application Ser. No. 10/718,254, filed Nov. 20, 2003 and entitled “Devices, Systems, and Methods to Fixate Tissue Within the Regions of the Body, Such as the Pharyngeal Conduit”; U.S. patent application Ser. No. 10/656,861, filed Sep. 6, 2003 and entitled “Magnetic Force Devices, Systems, and Methods for Resisting Tissue Collapse within the Pharaygeal Conduit”; U.S. patent application Ser. No. 10/236,455, filed Sep. 6, 2002 and entitled “Systems and Methods for Moving and/or Restraining Tissue in the Upper Respiratory System”; and U.S. Provisional Patent Application Ser. No. 60/441,639, filed Jan. 22, 2003 and entitled “Magnetic Splint Device and Method for the Treatment of Upper Airway Collapse in Obstructive Sleep Apnea;” and U.S. Provisional Patent Application Ser. No. 60/456,164, filed Mar. 20, 2003 and entitled “Device and Method for Treatment of Sleep Related Breathing Disorders Including Snoring and Sleep Apnea,” which have been incorporated herein by reference.
The system 200 desirably includes an implantation component 204, because of challenges that are presented in the placement of implants 206 in the dynamic tissue environment of the pharyngeal conduit. The implantation component 204 includes providing at least one tool 208 and/or instructions 210 for placing the implant 206 in a tissue region, e.g., through a percutaneous access path, using the tools described herein and shown in FIGS. 24 to 30; or by forming a surgical flap as described herein and shown in FIGS. 19 to 23; or by forming a surgical pocket, as also described herein.
The implantation component 204 can also include providing at least one tool 212 and/or instructions 214 for stabilizing the implant within a mucosa, or a submucosa, or against a fascia, or against or within a muscle, as described herein. Alternatively, the tool 212 and/or instructions 214 can make possible the stabilization of the implant against submucosa, or a fascia, or against or within a muscle, without stabilizing through a mucosa, as described herein. Other tools and instructions can be provided, e.g., to make various mechanical fixation materials (as described herein) accessible; or to make agents that stimulate rapid fibrosis (as described herein) available; or to provide antibiotic materials (as described herein).
The basic components 202 and 204 of the system 200 can be provided individually, or packaged in the form of a kit 216, as
The above-described embodiments of this invention are merely descriptive of its principles and are not to be limited. The scope of this invention instead shall be determined from the scope of the following claims, including their equivalents.
Claims
1. An implant comprising a biocompatible polymer matrix sized and configured to be implanted in animal tissue and magnetic particles bound with the biocompatible polymer matrix and being magnetized to possess a desired polarity.
2. An implant according to claim 1, wherein the magnetic particles comprise isotropic or anisotropic materials.
3. An implant according to claim 1, wherein the magnetic particles comprise a material selected from the group of NdFeB, SmCo, ferrite, and alnico.
4. An implant according to claim 1, wherein the biocompatible polymer matrix includes a material selected from the group of polycarbonate, silicone rubber, polyurethane, silicon elastomer, flexible plastic, and semi-flexible plastic.
5. An implant according to claim 1, wherein the biocompatible polymer matrix includes a flexible material.
6. An implant according to claim 1, wherein the biocompatible polymer matrix includes a tissue in-growth region.
7. An implant according to claim 1, wherein the magnetic particles form regions of different particle densities within the biocompatible polymer matrix.
8. An implant according to claim 1, wherein the magnetic particles comprise an essentially uniform particle density within the biocompatible polymer matrix.
9. An implant according to claim 1, further including at least one discrete permanent magnet encapsulated within the biocompatible polymer matrix with the magnetic particles.
10. An implant according to claim 9, wherein the permanent magnet and the magnetic particles are magnetized to have a common polarity.
11. An implant according to claim 1, further including at least one polymer-bonded magnet encapsulated within the biocompatible polymer matrix with the magnetic particles.
12. An implant according to claim 11, wherein the polymer-bonded magnet and the magnetic particles are magnetized to have a common polarity.
13. An implant according to claim 1, further including a flux shield comprising a soft ferromagnetic material coupled to the biocompatible polymer matrix.
14. An implant according to claim 1, wherein the desired polarity establishes a desired magnetic pole, and further including at least one stabilization magnet coupled to the biocompatible polymer matrix, the stabilization magnet including a magnetic pole that is the same as the desired magnetic pole and that is oriented normal or at an acute angle to the desired magnetic pole.
15. An implant comprising a structure sized and configured to be implanted in animal tissue, the structure including at least one magnet made from a hard ferromagnetic material and a flux shield comprising a soft ferromagnetic material overlaying at least a portion of the magnet.
16. An implant according to claim 15, wherein the magnet comprises a rare earth permanent magnet or a polymer-bonded magnet.
17. An implant according to claim 15, wherein the structure includes a flexible carrier for the magnet and flux shield.
18. An implant according to claim 15, wherein the structure includes a tissue in-growth region.
19. An implant according to claim 15 wherein the magnet includes a desired magnetic pole, the structure further including at least one stabilization magnet having a magnetic pole that is the same as the desired magnetic pole and that is oriented normal or at an acute angle to the desired magnetic pole.
20. An implant comprising a structure sized and configured to be implanted in animal tissue, the structure including at least one magnet made from a hard ferromagnetic material having a desired magnetic pole, and at least one stabilization magnet having a magnetic pole that is the same as the desired magnetic pole and that is oriented normal or at an acute angle to the desired magnetic pole.
21. An implant according to claim 20, wherein the magnet comprises a rare earth permanent magnet or a polymer-bonded magnet.
22. An implant according to claim 20, wherein the structure includes a flexible carrier for the magnet and the stabilization magnet.
23. An implant according to claim 20, wherein the biocompatible polymer matrix includes a tissue in-growth region.
24. A magnetic force system comprising an implant as defined in claim 1 or 15 or 20 implanted in animal tissue, and a source of magnetic force sized and configured for placement to interact with the implant when implanted in tissue.
25. A method for treating sleep disordered breathing comprising (i) placing at least one implant as defined in claim 1 or 15 or 20 in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and (ii) orienting a source of magnetic force to interact with the implant to resist collapse of the tissue region.
26. A method according to claim 25, wherein step (i) includes placing the implant into a surgical pocket.
27. A method according to claim 25, wherein step (i) includes placing a receptacle into a surgical pocket and placing the implant into the receptacle.
28. A method according to claim 25, wherein step (i) includes placing the implant in an implantation site through a surgical tissue flap.
29. A method according to claim 25, wherein step (i) includes placing the implant in an implantation site through a percutaneous access path.
30. A method according to claim 25, wherein step (i) includes stabilizing the implant within a mucosa, or a submucosa, or against a fascia, or against or within a muscle.
31. A method according to claim 25, wherein step (i) includes stabilizing the implant against a submucosa, a fascia, or against or within a muscle, without stabilizing through a mucosa.
32. A method according to claim 25, wherein step (i) includes encouraging tissue in-growth on the implant.
33. An implant system comprising an implant sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and means for forming a percutaneous access path for placing the implant in the tissue region.
34. An implant system comprising an implant sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and means for forming a surgical flap for placing the implant in the tissue region.
35. An implant system comprising an implant sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and means for forming a surgical pocket for placing the implant in the tissue region.
36. An implant system according to claim 33 or 34 or 35, further including means for stabilizing the implant within a mucosa, or a submucosa, or against a fascia, or against or within a muscle.
37. An implant system according to claim 33 or 34 or 35, further including means for stabilizing the implant against a submucosa, or a fascia, or against or within a muscle, without stabilizing through a mucosa.
38. A method for providing treatment for a physiologic condition comprising (i) providing an implant sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and (ii) providing at least one tool and/or instructions for placing the implant in the tissue region through a percutaneous access path.
39. A method for providing treatment for a physiologic condition comprising (i) providing an implant sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and (ii) providing at least one tool and/or instructions to form a surgical flap for placing the implant in the tissue region.
40. A method for providing treatment for a physiologic condition comprising (i) providing an implant sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and (ii) providing at least one tool and/or instructions to form a surgical pocket for placing the implant in the tissue region.
41. A method according to claim 38 or 39 or 40, further including providing at least one tool and/or instructions for stabilizing the implant within a mucosa, a submucosa, or against a fascia, or against or within a muscle.
42. A method according to claim 38 or 39 or 40, further including providing at least one tool and/or instructions for stabilizing the implant against a submucosa, or a fascia, or against or within a muscle, without stabilizing through a mucosa.
43. An implant comprising an implant body sized and configured to be implanted in a targeted tissue region comprising at least one pharyngeal structure or at least one anatomic component within a pharyngeal conduit, and stabilization elements carried by the implant body to anchor the implant in the targeted tissue region.
44. An implant according to claim 43, wherein the stabilization elements including at least one elastic member.
Type: Application
Filed: Mar 22, 2004
Publication Date: Jul 21, 2005
Applicant:
Inventors: Lionel Nelson (Los Altos, CA), Jinfang Liu (Lancaster, PA), Ryan Boucher (San Francisco, CA), Eric Doelling (Sunnyvale, CA), J. Stine (Longview, TX), Lawrence Jones (Conifer, CO)
Application Number: 10/806,372