MXPA00007905A - Medical implants of stretch-crystallizable elastomers and methods of implantation - Google Patents

Abstract

Reduced trauma medical implants (10), and methods for their use are disclosed wherein at least a portion of the implant is formed of a stretch crystallizable elastomeric material formulated to exhibit the property of stretch crystallization upon substantial elongation of the implant to form stable, small incision implant configurations having at least one dimension substantially reduced for insertion through a surgical incision that is small relative to the incision size necessary to implant the un-stretched implant. Exemplary embodiments include intraocular implants formed of optically clear, high refractive index stretch crystallizable silicone elastomers formulated to stretch crystalize at near ambient temperatures upon elongations greater than or equal to 300%, and to recover their original configurationimmediately upon exposure to body temperature following implantation.

Description

MEDICAL IMPLANTS OF ELASTOMEROS CRISTALIZAB IS BY STRETCHING AND METHODS OF IMPLEMENTATION FIELD OF THE INVENTION The present invention relates in general to stretch-crystallizable elastomeric medical implants and methods for the insertion and placement of these medical implants, in particular optical lenses. More particularly, the present invention is directed to elastomeric, highly expandable implants that are formed from stretch crystallizable elastomers, preferably silicone, which are stretched significantly to induce higher, stable melting point crystals, but reversible, to produce small, stable, elongated, deformed implant configurations for use in small incision implantation techniques. Within a few seconds of being inserted into the body and subjected to normal body temperature, the stretch-induced crystals melt, allowing the implants to return to their original dimensions, shapes, and physical characteristics.

BACKGROUND OF THE INVENTION There are many well-developed applications and techniques known in the art for the replacement or augmentation of natural body parts with medical implants. These medical implants can be divided into two general classes of implanted medical devices. The first class includes implants that perform useful and essential functions, which are based on a variety of mechanical properties, including strength and flexibility. Examples of these implants include replacement heart valves and artificial joints. The second class includes implants that perform useful and essential functions by virtue of the physical form of the implant, rather than by its structural or mechanical properties. Examples of this class of implants include cosmetic devices that are designed to augment or replace missing tissue or, more importantly, artificial optical lenses that are designed to augment or replace the natural lens of the eye. Although medical implants of this second class have been used successfully for many years, their use is not free of problems. One of the main difficulties is the physical trauma caused by the surgical incisions that must be made in the body, to place the implants. It is well known in the medical art that reducing the size of the surgical incision that is needed for the implantation procedure will reduce this trauma. At this time, reducing the size of the surgical incision is best achieved, when possible, by reducing the size of the implant itself. Alternatively, recent research and development has focused on reducing the size of the surgical incision itself. By using arthroscopic or microsurgical techniques and instruments, the surgeons performing the implantation can confine the physical impact of the surgical procedure to the desired target location through small, usually distant, incisions. These small incisions reduce much of the trauma that is normally associated with surgery using conventional large incision techniques. As a result, you can reduce a lot of discomfort, healing time and complications, with small incision techniques. This research has not been simple because the volume, dimensions, and relative stiffness of conventional implants place practical limits on the available reduction in incision size. Although they are relevant to many types of prosthetic and cosmetic implants, this problem is typified by artificial optical lenses, which are known as infraocular lenses or "IOLs" (for its acronym in English). These artificial lenses are implanted inside the eye to replace or enhance natural lenses and their ability to focus light on the retina of the eye. In this functional context, is the shape and volume of the lenses, in conjunction with the refractive index of the lens material, which causes the light entering the eye and passing through the lens to be appropriately focused on the retina that allows the clear vision. Currently, most of the most practical infra-ocular lens implantation procedures require an incision in the eye that is greater than 3 millimeters (mm) to 4 millimeters. In most cases, an intraocular lens is implanted after removal of the damaged natural lens or with cataracts. Currently, the procedure for the removal of natural lenses requires an incision of at least 3 to 4 millimeters. However, the typical infra-ocular lens implant includes an optical light that focuses the lens portion and smaller structural projection characteristics ("haptics") that help the placement and retention of lenses inside the eye, after implantation. The most available IOLs currently have a minimum diameter in the order of 6 millimeters and a minimum thickness of 1 to 2 millimeters. More recently, the lenses known as "life-size optics" have been developed, which were intended to completely replace natural lenses, having minimum diameters ranging from 8 millimeters to 13 millimeters and minimum thicknesses that They fluctuate from 3 millimeters to 5 millimeters. In this way, a surgical incision must be made that is at least as large as the minimum dimension of the optic implant. There are significant disadvantages to the use of any incision in the eye, especially those that are greater than 3 millimeters or 4 millimeters. These disadvantages include astigmatism or corneal distortions after the operation, as well as the potential for increased complications and healing time. A known method for reducing the size of the surgical incision that is associated with the implantation of an intraocular lens is to form the lenses from a relatively flexible material which is folded or rolled to reduce the size of a dimension, before insert the lenses in the eye. Once implanted, it is intended that the lens unfolds and return to its original shape. Folding lenses, although suitable for the purposes for which they were proposed, have disadvantages that limit their use for small incision surgical implantation and can make them impractical. For example, when they are folded, only one of the three dimensions, the diameter or the width can be reduced, and this only in half. At the same time, one of the other dimensions, the thickness, necessarily bends to one half of the largest dimension, which in the case of the lens configurations that are currently available, remains in the order of 4 millimeters to 6 millimeters of length. In addition to compositional matters, the folding of the lenses can produce permanent folds or deformations in the optical portion of the lens, causing visual distortion after implantation. An alternative method that has been proposed to reduce the size of the incision during implantation is the use of expandable lenses that are manufactured from materials such as hydrogels. The hydrogel lenses are dehydrated prior to insertion to reduce the volume and overall dimensional characteristics of the lens. After implantation, it is intended that the hydrogel material be rehydrated and expanded back to its original size. Although these hydrogel lenses are capable of significant reductions in size, the current state of the hydrogel technique requires a period of rehydration after implantation, which ranges from 3 hours to 24 hours. This period of time is impractical because the surgeons performing the implantation can not determine whether the lens is properly placed in the eye before finishing hydration. As a result, surgeons who perform implantation may be reluctant to wear these lenses, because they are required to wait before closing the implantation incision, until surgeons are sure that access to the interior will no longer be necessary. of the eye to replace the lenses. Other methods have been proposed for the surgical implantation of small incision of infraocular lenses, but with little success. In one proposal, transparent balloon lenses should be inserted in their empty or deflated state inside the eye through a small incision. Once inserted into the eyes, the proposed balloons should be filled with a highly refractive material to inflate the lenses to their final configuration. So far, it has been proven that balloon lenses are impractical as they are difficult to manufacture and inflate with some degree of accuracy or control after implantation. further, there are unresolved difficulties with the materials, the removal of bubbles, and with the sealing of the lenses. Similarly, injectable lenses have been proposed to replace the lens of the natural eye in itself, where a liquid polymer would be injected into the lens capsule of the naturally occurring eye and allowed to cure to its final configuration . Current technology has not been able to produce these lenses because it is difficult to produce predictable optical energy and resolution with biocompatible materials. In U.S. Patent Application Serial No. 08 / 607,417, currently pending, a more practical and workable method for reducing the size of the surgical incision that is used when an intraocular lens is implanted is disclosed. With this technique, the lenses are formed from a memory material, i.e., a material that has the ability to be transformable into shape, such as elastomeric or gelatinous materials that can deform substantially recoverable in all directions. These lenses are implanted through a small incision in the eye using a tubular, small diameter ejector. After implantation, the gelatinous lens implants immediately resume their pre-implant forms and configurations, allowing the surgeon performing the implantation to confirm the proper placement and completion of the implantation procedure. However, even this technology can be improved.

For example, when these lenses are deformed and placed inside the tubular ejector, the lenses are forced into a shape having a high surface-to-volume ratio. Under these conditions, there could be strong elastomeric forces exerted by the deformed lenses in the tubular ejector, since the deformed lenses try to recover their original size and shape. These forces, coupled with the high surface-area-to-volume ratio, can make it difficult to push the deformed lenses out of the tubular ejector and into the eye. In accordance with the foregoing, one of the objectives of the present invention is to provide an implantation methodology that will allow the simple and rapid insertion and placement of medical implants, through very small surgical incisions in relation to the size of the implant, without the use of complicated or sophisticated implant transfer techniques or systems. It is a further object of the present invention to provide surgical implants such as intraocular lenses that can be inserted and placed inside a patient, through a very small incision in relation to the shape, size, and volume of the implant. It is still another object of the present invention to provide stretch-crystallizable intraocular intraocular lenses that are optically clear, have high refractive indices, and that can be stretched into long, thin rods or sheets that crystallize and stabilize at temperatures below the temperature. normal of the body, and which again take their crystallized shape, contour and physical characteristics that they had before the stretch, seconds after being implanted inside the eye.

COMPENDIUM OF THE INVENTION These and other objects are achieved by means of the compositions, implants, methods, and associated apparatus of the present invention which can quickly and easily insert and place the deformable crystallizable medical implants by stretching inside the patient's body. In accordance with the broad, functional aspects of the present invention, the medical implants of the present invention are formed from novel, biocompatible, stretch-crystallizable elastomers, preferably silicone, with refined physical properties which, as they stretch significantly, in the order of 300 percent or more, they form molecular crystals of higher melting point due to the new orientation of their stretched molecular structures. As a result, they can be stretched and deformed into easily stabilized, easily manipulated, long sticks or blades at temperatures below normal body temperature, but temperatures that are not so low as to be costly or difficult to get or work with them. Once implanted, the higher melting point crystals become hot and melt causing the implants to recover their original sizes, shapes, contours and properties immediately after being exposed to higher body temperatures. In accordance with the teachings of the present invention, the stretch-crystallizable elastomers are formulated to have practical glass melting temperatures that allow the implants formed from the elastomers to be crystallized by stretching at about ambient temperatures, in configurations of Small incision stable in very short, convenient periods of time, with minimal effort. If desired, the cooling of the stretched implants will accelerate the formation of the internally induced stretch microcrystals, which function as "fillers" similar to transient crosslinkers to molecularly fix the deformed implants in stable, but reversible, frozen configurations. . These configurations frozen by form, crystallized, can be easily maintained with simple cooling that allows the implant surgeon to manipulate and position the implants without special tools or cooling devices or fear that the implants will prematurely "melt" back into its original configurations. Medical implants that are formed from these stretch-crystallizable materials solve the problem of providing the practical apparatus and methods for implantation of medical devices that significantly reduce the size of the surgical incisions needed to implant the devices. . In accordance with the teachings of the present invention, materials exhibiting stretch crystallization are beneficial in any application in which it is desired to implant an elastomeric medical device through a passage smaller than the original dimensions of the implant. One of the main benefits of using the stretch-crystallizable materials of the present invention is that the materials can be stretched and crystallized at temperatures below body temperature (about 37 ° C). In addition, medical implants that are formed in accordance with the teachings of the present invention can be implanted through very small surgical openings, either directly or with the use of generally small tubing placement devices to provide Reduced trauma accesses to target sites inside the patient's body. The novel compositions and implants and associated methods of the present invention have numerous features and advantages that distinguish them from the prior art. For example, stretchable crystallizable elastomeric materials are biocompatible and, for optical purposes, are formulated to be optically transparent with relatively high refractive indices, analogous to those of natural human eye lenses. In addition, the elastomers are "tuned" by the specific formulation to exhibit crystallization by stretching at temperatures in ranges usable in relation to ambient or environmental temperature (approximately 20 ° C) and body temperature (approximately 37 ° C). What is more, the elastomers are capable of significant elongation where they develop an increased tensile strength due to the formation of microscopic crystals of higher melting point during stretching, which act as transient reinforcing fillers. However, they exhibit a 100% recovery after stretching to their original configurations, because they lack the conventional, non-stretchable strengthening fillers, such as the fumed silica crosslinkers found in prior art elastomers. In this manner, the materials of the present invention can be formulated to provide crystallization temperatures by stretching ranging from -100 ° C to 50 ° C and recovery temperatures ranging from 25 ° C to 50 ° C. These materials produce unprecedented implants that are proposed for surgical implantation of small incision. For example, the implants of the present invention can be stretched in at least one direction to a dimension that is in the order of 300 percent to 600 percent of their original size. In this way, while the volume of the implants remains constant, their three-dimensional shapes can be significantly altered in small, stable dimensioned shapes that will pass easily and quickly through very small incisions or implantation devices of small internal diameter, with a minimum effort. When implanted through an implantation device, the stretch-crystallized implants do not exert a significant elastomeric force against the internal walls of the device. In this way, only a small force is required to push the implant of crystallized material in, through, and out of the device within the target implantation site. The stretch-crystallized implants of the present invention also exhibit recoverable deformation within a few seconds of being implanted and exposed to normal body temperatures. This provides the surgeon who makes the implantation with an immediate confirmation of a successful implantation, without the need for manipulations or complex techniques after implantation. The present invention is particularly suitable for the production and implantation of optical lenses and contact lenses that can be implanted inside the eye, for corrective purposes or for replacement purposes. (pseudophakia), The exemplary optical lens implants of the present invention are formed from stretch-crystallizable, biocompatible silicone elastomers. Exemplary silicone elastomers are formed in accordance with the teachings of the present invention, by polymerizing what is known in the art as an F3 monomer, such as methyl (3, 3, 3-trifluoropropyl) siloxane, in a exemplary cis / trans ratio ranging from about 40/60 to 100/0, in a homopolymer or copolymer with a monomer having a higher refractive index than monomer F3, such as, what is known in the art as a monomer D3 (2Ph) such as hexaphenylcyclotri-siloxane. The resulting exemplary polymer has a composition of from 60 percent to 100 percent of monomer F3 and from 0 percent to 40 percent of monomer D3. These exemplary stretch crystallizable elastomers are biocompatible, optically transparent and exhibit a refractive index in the order of 1.4, which makes them particularly well suited for the construction of IOLs. Optical lens implants can be configured as full-size lenses, which have diameters in the order of 8 millimeters to 13 millimeters and central thicknesses of 3 millimeters to 5 millimeters, which can completely fill the capsular bag, or as single or multi-piece optics of 5 millimeters to 7 millimeters in conventional size, with 1 millimeter to 2 millimeters in central thickness and which may include one or more haptic support structures that extend radially. The transverse shape of the optical lenses can be of any shape, including plano-convex, biconvex, converging meniscus, divergent meniscus, plano-concave, biconcave and globe-shaped. Broadly speaking, one embodiment of the associated implantation method of the present invention simply includes the crystallization of the elastomeric implant at a temperature lower than the normal body temperature and the direct insertion of the deformed implant at a target site within the body of a patient. For example, after having crystallized to form a long, thin, relatively rigid swab, the surgeon can manipulate the implant by means of forceps, or other similar apparatus, and insert it directly into the body through a relatively small surgical incision. Once inside the body, the implant is exposed to normal body temperature and, in a few seconds, the implant returns to its crystallized size and configuration that it had before stretching. In an alternative embodiment, the crystallized implant can be loaded by stretching into an implantation device having a small diameter, generally of tubular outlet. The insert device is placed in a target site within a patient's body and the implant is pushed through the tubular outlet into the target site. If desired, the diameter of the elongate tubular outlet may be small enough to facilitate the output to function as a piercing cannula, analogous to a hypodermic needle that can form its own access path. Alternatively, a small surgical incision can be made using conventional surgical incision techniques, and the tubular outlet can be inserted therethrough. In any of the embodiments, the present invention allows an intraocular lens implant to be implanted into the eye, through a very small surgical incision that may fluctuate between 1 millimeter and 4. 5 mm. Other objects, features, and advantages of the present invention will become apparent to those skilled in the art, from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention. present invention in the context of an exemplary IOL implant, but equally relevant for other implants that could include elastomeric portions.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a perspective view of a stretch crystallizable implant that is configured as an intraocular lens implant, in accordance with the present invention, which particularly illustrates an undrawn configuration of the implant; Figure 2 is a cross sectional view of the exemplary unstretched implant, taken along line 2-2 of Figure 1; Figure 3 is a perspective view of a stretch-crystallizable implant of the present invention, particularly illustrating a stretched configuration of the implant; Figure 4A is a cross sectional view of the exemplary stretched implant, taken along line 4-4 of Figure 3; Figure 4B is an alternative cross sectional view of the exemplary stretched implant, taken along line 4-4 of Figure 3; Figure 5 is a view of an eye and a stretch-crystallizable implant in a stretched and stabilized configuration, particularly illustrating an implantation procedure in accordance with the present invention; Figure 6 is a view of the eye and the stretch crystallizable implant of Figure 5, illustrating another step of the implantation procedure; Figure 7 is a view of the eye and the stretch-crystallizable implant of Figure 6, illustrating the implant in the unstretched configuration, after implantation and retrieval of its original physical configuration and properties; Figure 8 is a cross sectional view of an implantation device for implanting a stretch-crystallizable implant of the present invention; Figure 9 is a fragmentary diagrammatic cross sectional view of an eye and an implantation device, illustrating a first step in an exemplary implantation procedure of the invention; Figure 10 is a fragmentary diagrammatic cross sectional view of the eye and the exemplary implantation device illustrating a subsequent implantation step to that shown in Figure 9; Figure 11 is a fragmentary diagrammatic cross sectional view of the eye and the exemplary implantation device illustrating a subsequent implantation step to that shown in Figure 10; Figure 12A shows a diagrammatic fragmentary cross sectional view of the eye and the exemplary implantation device illustrating a subsequent implantation step to that shown in Figure 11; Figure 12B is a fragmentary diagrammatic cross sectional view of the eye and the exemplary implantation device, illustrating the implantation of an alternative implant; Figure 13 is a perspective view of an assembly for shaping or forming a stretch-crystallizable implant of the present invention, in a stretch-crystallized configuration, illustrating the assembly prior to shaping the implant; Figure 14 is a view similar to that of Figure 13, illustrating the assembly after shaping the implant in a stretch-crystallized configuration; and Figure 15 is a cross sectional view of another exemplary embodiment of a stretch crystallizable implant, which is configured as an intraocular lens in accordance with the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY MODALITIES Referring more particularly to the drawings, Figures 1 and 2 illustrate a medical implant that can be crystallized by stretching and transformable in a manner that was produced in accordance with the teachings of the present invention. For purposes of explanation and without limiting the scope of the present invention, exemplary implant 10 is illustrated as an intraocular lens to demonstrate the unique characteristics of the present invention in a simple context. Alternative function implants are contemplated as being within the scope of the present invention, as will be understood by those skilled in the art. Those skilled in the art will also appreciate that exemplary lens implants should be optically transparent and that they should possess an appropriate refractive index to function as lenses. However, these additional properties are not essential for all implants that are produced in accordance with the teachings of the present invention.

The exemplary implant 10 is formed from a stretch crystallizable elastomer such as one of the exemplary silicone compositions discussed herein. When stretched significantly, these novel elastomers form molecular or "microtamable" crystals with relatively higher melting points than those of their unstretched states, due to the new molecular orientation of alignment of the stretched elastomeric structures. Figures 1 and 2 illustrate the exemplary implant 10 in an unstretched configuration, and Figures 3 and 4 illustrate the implant in a frozen, stretched and stable configuration facilitating its uncomplicated implantation through a small incision. Those skilled in the art will appreciate that a significant degree of stretching is necessary to induce stretch crystallization. This is totally different from the localized, simple deformation, which is used in collapsible implants. Due to the fine tuning physical properties that are uniquely designed of the stretch-crystallizable elastomers of the present invention, the exemplary implant 10 can be stabilized quickly and easily in the stable, but reversible stretched configuration, within a range of Practical temperature, previously determined in which it is easy to work and which does not require that expensive equipment or procedures be maintained.

For example, the previously determined range can be formulated to range from -100 ° C to 50 ° C. Preferably, the temperature range will range from about freezing, for example, to about 0 ° C, to temperatures at or near the normal body temperature, for example, at about 40 ° C. These exemplary stabilization temperatures of the previously determined stretch crystallization can be achieved by simple cooling, liquid nitrogen, liquid C02, or simply by immersing the implant 10 in an ice bath or in cold water. Which crystallization temperatures by stretching will be used, will depend on the physical properties of the stretch-crystallizable elastomers that are used in accordance with the teachings of the present invention. A number of exemplary novel silicone elastomers with stretch-crystallizable temperatures that are uniquely formulated, which makes them particularly suitable for forming medical implants that can be transformed into shape, close to room temperature (20 ° C) are described herein. C at 25 ° C), in the stable small incision configurations of Figures 3, 4A and 4B. The stabilization of the implant 10 in the form transformed into crystallized appearance, can be achieved in a few minutes or the few seconds of having been exposed to the previously determined appropriate temperatures. It should be noted that once they are stabilized, the elastomers remain substantially rigid and are less flexible, stretchable, or narrowed. The cooling of the crystallized implant by stretching accelerates the formation of the crystal inside the crystallized implant and stabilizes the transformed configuration more rapidly. However, cooling is not essential for the practice of the present invention since the stabilizing crystals are formed over time, as long as the implant is maintained in the shape-transformed, deformed configuration where stretching crystallization occurs. After being stabilized in the small incision configuration, transformed into stretched aspect, as exemplified in Figure 3, the implant 10 can be stored, transported, or manipulated by the implantation surgeon, with a minimum of difficulty and without difficulty. the fear that the implant will return to its configuration not crystallized by stretching. This greatly facilitates its implementation, as taught in the present. Of equal importance, the implant 10 can quickly recover its configuration and crystallized properties without original stretching, simply by allowing the implant to warm to body temperature after implantation. This happens a few seconds after implantation, without any additional action on the part of the surgeon who performs the implantation. This recovery of substantially 100 percent of the configuration and properties includes the recovery of the original size and shape in its three dimensions, and where appropriate, includes the refractive index and optical clarity. In accordance with the present invention, the preferred melting point temperature of the implant 10, should fluctuate from about 25 ° C (slightly above the environment) to the normal body temperature of about 37 ° C. Preferably, the elastomers from which the exemplary implant 10 is made, are stretchable to a crystallized configuration by stretching to a dimension which, at least in one direction, is at least about 300 percent to 600 percent greater than the unstretched, original dimension. For example, with the exemplary implant 10 configured as an intraocular lens as shown in Figures 1 and 2, the lenses can have an exemplary diameter D of approximately 9 millimeters and a central thickness t of approximately 4.5 millimeters when in the unstretched condition. . When in the stretched, rod-shaped or leaf-shaped, small incision configuration, the implant 10 may have a length 1 of about 40 millimeters to 50 millimeters and a diameter d of about 1 millimeter to 3 millimeters, as shown in FIG. Figure 4A. Figure 4B shows a cross section in the form of an alternative leaf which can mimic the shape of a surgical incision. This increase in one dimension from a diameter D of 9 millimeters to a length 2 of 50 millimeters, represents about a 350 percent increase in this dimension. Concurrently with this 350 percent increase, the lens implant 10 experiences a substantial decrease in at least one other dimension. In this example, from a thickness T of 4.5 millimeters, to a diameter or cross section d of 1 millimeter, as shown in Figures 4A and 4B. This decrease represents approximately a 75 percent decrease in this dimension. More importantly, this decrease to about a 1 millimeter dimension means that the implant 10 can be inserted into a patient through an incision that is relatively small when compared to that which would be required for the implant 10 in the Unstretched configuration. In this example, the incision of the implant needed to implant the stretched, rod-shaped configuration of Figure 4 can be less than about 2 millimeters, contrary to an incision greater than 9 millimeters that is needed for implantation of the implant without stretching . Those skilled in the art will appreciate that the implant volume remains relatively constant between the stretch-crystallized configuration, transformed into appearance and the original configuration, without stretching. This places a practical constraint on the amount of stretching that can be imparted to the implant, because the reduction of one dimension necessarily increases at least one of the others. As a result, if the diameter d of Figure 4A is made too small, the length 1 of Figure 3 becomes too long. In the case of an intraocular lens implant as illustrated in Figure 1, excessive stretching of the lenses will result in a rod-shaped configuration that will be too long to fit at the intended implantation site within the eye. In this way, for a conventional 6 mm intraocular lens implant that weighs approximately 20 milligrams, the implant can be crystallized by stretching to a configuration transformed into an appearance of approximately 20 millimeters in length and 1 millimeter in diameter. In contrast, for a life-size intraocular lens implant weighing approximately 160 milligrams, the implant crystallized by stretching, transformed into appearance, will have a length of approximately 20 millimeters to 30 millimeters and a corresponding diameter of 2 millimeters to 3 millimeters, Stretching the life-size intraocular lens to a diameter of 1 millimeter will produce an implant about 160 millimeters long, which could not be implanted inside the eye. Naturally, for implants that are proposed to be placed elsewhere in a patient's body, these restrictions may vary accordingly. It should be noted at this point, that a particularly unique advantage of the present invention is the functional impact on the exemplary infra-ocular lens implants described herein. So far, it has been difficult to implant life-size infra-ocular lenses because of the relatively large incision that is required. Associated implantation trauma can counterbalance the desired advantages of full-scale IOL, which include eliminating decentralization, tilt or misalignment of the lenses after implantation. However, using the teachings of the present invention, life-sized IOLs can now be implanted through very small implantation incisions of 3 millimeters to 4 millimeters. This unique advantage of the present invention illustrates the relevance of the exemplary IOL embodiments, as samples of the features and unprecedented advantages of the invention. With this newly emphasized understanding of the non-limiting, exemplary nature of the IOL implants that are described herein, the applicable broadly applicable methods of implantation that are provided in accordance with the teachings of the present invention will now be illustrated, with reference to Figures 5-7. In a broad aspect, the methodology of the implantation of the present invention includes the simple steps of providing a transformable implant in aspect, crystallisable by stretching, crystallizing by stretching the implant in a small, stable incision implant configuration, and inserting the implant crystallized by stretching through a small incision inside a patient's body. This method of implantation may include the additional step of cooling the crystallized implant by stretching to induce the formation of stronger, more stable microcrystals by accelerating the crystallization process by stretching. In any of the alternatives, the configuration of the small incision implant, crystallized by stretching the implant, is sufficiently rigid and can be manipulated in a simple manner to allow the surgeon performing the implant to directly insert the transformed implant in aspect through the implant. small incision, inside a target implantation site inside the body of a patient. The exemplary implant 10 can be stretched and / or tightened in a small incision configuration, stretched by simple manipulation with medical implements, such as forceps, by pulling the opposite portions of the implant away from each other. Preferably, the implant 10 is formed of a material that is configured to allow this method of stretching and / or tightening to be performed close to ambient or environmental temperatures. Once in the stretched configuration (e.g., as shown in Figure 3), the lens implant 10 can be stabilized in the small incision implant configuration by simply holding the implant 10 in the stretched position until the crystallization by stretching has proceeded to the point where the transformed form maintains itself. This process can take from several seconds to several minutes, depending on the materials, properties and volume. Because the crystallization by stretching actually elevates the melting temperature of the crystals, above that of the unstretched implant material, the proposed stretching conditions are below its new, higher melting point, which will cool the implant to a stable configuration, transformed into appearance. Preferably, in accordance with the teachings of the present invention, the small incision implant configuration will generally be elongated with a circular, elliptical or leaf-shaped cross section, as shown in Figures 3, 4A and 4B. As noted above, the stabilization of the implant crystallized by stretching, transformed into appearance, can be accelerated by immersing the stretched implant in ice or cold water, which can have a temperature between 0 ° C and about 4 ° C in this exemplary mode. The implant 10 is stabilized in the crystalline stretched configuration in a short period of time, in this example, approximately 20 seconds. With specific reference to Figure 5, the implant can be inserted through incision 14 by any suitable method. For example, forceps 16 holding one end of the stretched implant may be used to push the implant 10 through the incision. The forceps 16 can be cooled to a temperature below the melting point of the implant 10 to prevent inadvertent heating of the implant. As mentioned above, the implant 10 is substantially rigid when it is stabilized, which facilitates that the implant 10 is easily manipulated during insertion. As shown in Figure 6, when the stretch-crystallized implant 10 enters the anterior chamber 18 of the eye 12, the implant 10 is subjected to normal body temperatures within the eye 12. Accordingly, the implant 19 is it crystallizes and begins to recover its crystallized configuration without stretching, original. Within a few seconds of being inserted into the eye 12, as shown in Figure 7, the implant 10 completely recovers its original unstretched configuration as it is placed inside a desired target site, such as the posterior chamber. twenty.

Referring now to Figure 8, one embodiment of the alternative implantation method employing an implantation device 22 for positioning the implant 10 in the eye 12 is illustrated. The exemplary implantation device 22 includes a tubular portion 24 and a plunger 26. The plunger 26 includes an end piece 32 which is slidably received inside the chamber 28. The tubular portion 24 includes an internal chamber 28 and an outlet 30. The implant 10 is received inside the chamber 28 after being crystallized by Stretching, in an elongated configuration, in the form of an elongated rod or in the form of a leaf, of a small incision. As shown in Figure 9, rather than directly inserting the crystallized implant by small incision stretch 10 through an incision 14 in the eye 12, the outlet 30 of the implantation device 22 can be directed into the in-position. of the patient's body, to deposit the implant 10 at the target site. Alternatively, the diameter of the tubular portion 24 can be configured to be relatively small, so as to function as a piercing cannula, analogous to a hypodermic needle. As such, the tubular portion 24 can form its own incision or access path through the tissue, thereby eliminating the need to cut or form an incision with a separate passage. The tubular portion 24 can be cooled below the melting point of the implant 10, so as to maintain the implant in the crystallized configuration by stabilized stretching. The tubular portion 24 may also function to isolate the implant 10 from the relatively warm body temperature of the implantation site, until the implant is pushed from the implantation device 22. By keeping the implant 10 in the crystallized configuration by stabilized stretching, it is it prevents the implant from exerting some force outwardly on the walls of the chamber 28, so that only a small force is required to push the plunger 26 inside the tubular portion 24 to push the implant 10 from the outlet 30 in the position in the target site of the implant. A viscoelastic fluid 28, such as the Healon * available with Pharmacia, can be added to chamber 28 to provide lubrication. Regardless of whether exit 30 is used to pierce its own access path or is simply inserted through a small surgical incision, once tubular portion 24 has been placed inside the patient's body with exit 30 directed towards the site The objective of the implant, as shown in Figure 10, pushes the plunger 26 inside the tubular portion 24 to drive the implant 10 at the target site. As illustrated in Figures 9-12A, the exemplary target site is the posterior chamber 20 of the eye 12 and the implant 10 is a life-size intraocular lens implant. Alternatively, where the implant 10 is configured to function as an implantable contact lens, which is intended to function in a position opposite the natural lens of the eye, the implantation device 22 makes it possible to apply the implant to the target site through a very small incision. This is because the incision of 3 millimeters to 4 millimeters normally associated with the removal of cataracts is unnecessary for the implantation of an implantable contact lens. In this way, it is not necessary more than a simple puncture or minimal incision of sufficient size to accommodate the passage of the implantation device 22 within the eye. As a result, with the present invention, implantation incisions in the order of 1 millimeter to 2 millimeters can be achieved. Such small incisions can completely avoid the need for post-implantation suturing, and provide the implantation surgeon with practical access alternatives, which include scleral access directly into the posterior chamber 20 of eye 12, or the corneal access. scleral to the anterior chamber 18 or to the posterior chamber 20, as shown in Figure 12B. Again, it should be emphasized that infraocular lens implants are illustrative of the principles of the present invention, and are not intended to limit the invention to infraocular lenses only.

An alternative method for crystallizing by stretching and transforming the shape of the implants of the present invention is illustrated in Figures 13 and 14. Instead of simply pulling on the opposite portions of the implant 10 to stretch the implant in one direction, as shown in Figure 13, the implant 10 can be crystallized by stretching in a stable, small incision, deformed implant configuration with a template of . compression generally indicated with reference 32. Compression template 32 includes a female mold 34 and a compression piston 36. The mold 34 is provided with a receiving groove 38 that defines the mold cavity 40. The compression piston is provided with a projecting guide 42, dimensioned to fit slidably within the receiving slot 38. The projecting guide 42 itself is provided with a mating face 44, which is dimensioned to engage with, and complete the configuration of the mold cavity. 40, to define a small incision implant configuration when the projecting guide 40 is completely inserted into the receiving slot 38. In use, a stretch-crystallizable implant, such as the exemplary implant 10, is placed inside the slot. receiving 38, and the protruding guide 42 of the compression piston 36 is pressed into the receiving slot 38, directing the implant 10 of The cavity of the mold cavity 40. This process compresses the implant 10 into the mold cavity 30 with an oppressive action which causes the implant 10 to stretch along the longitudinal axis defined by the mold cavity 40. It can be using water or a viscoelastic fluid to facilitate the oppression of the implant 10 within the mold cavity 40. The mold 34 and the plunger 36 may include a structure for guiding the outgoing guide 42 within the receiving slot 38, in a consistent manner and controlled. Those skilled in the art will note that the stretching of the implant 10 is not completely uniform throughout the extension of the implant material. Therefore, the different portions of the implant 10 will stretch to different degrees. However, as shown in Figure 10, when the protruding guide 42 of the compression piston 36 has been completely received in the receiving groove 38, the implant 10 deforms significantly in an elongated, blade-shaped implant configuration. or rod, small incision. Simply maintaining the implant 10 in this configuration will result in the formation of transient stabilizing bonds crystallized by stretching inside the implant material 10, forming a stable implant, transformed in its shape, crystallized by stretching. Alternatively, cooling the implant 10 crystallized by stretching within the compression insole 32 will accelerate and improve this process. The cooling can be done through the simple immersion of the compressed implant and the compression template assembly in a water bath, or through simple cooling. In the exemplary embodiment of the compression jig 32 shown in Figures 13 and 14, the mold cavity 40 is configured to have a transverse diameter or width m of 2.5 millimeters or less, and a length ranging from 30 millimeters to 50 mm. This configuration is suitable for the crystallization by stretching of the life-size infra-ocular lens implants. Those skilled in the art will note that alternative dimensions may be used as appropriate. At this point it should be noted that although the exemplary lens implant 10 shown in Figures 1 and 2 has a biconvex lens element, it is contemplated within the scope of the present invention to configure the light focusing lens elements of the lens implants in any of a wide variety of optical lens configurations, depending on the needs of light focus or the intended function of the lens and the target site. Exemplary alternative transverse lens shapes or configurations may include biconvex, plano-convex, or concave-convex or meniscus, as those of ordinary skill in the art know. Other configurations of alternative transverse lenses are also within the scope of the present invention. In addition, although the exemplary lens implant 10 is shown in Figure 1 without any supporting or "haptic" structure, it is contemplated as being within the scope of the present invention that the lens implant 10 may include that support haptic, as those of ordinary experience in the art know. That support haptic need not be made of the stretch-crystallizable elastomers, and may generally include flat blade haptics, cycle haptics, or even circular flange support haptics, generally flat. Other configurations of alternative haptic supports are also within the scope of the present invention, as dictated by the individual patient's support and placement needs or the design of the lens. The lens implants made in accordance with the teachings of the present invention can also be formed as balloon-shaped lenses, such as the implant 50 shown in Figure 15. The balloon implant 50 has an elastomeric skin 52, which defines an internal chamber containing a more fluid material 54. The exemplary skin 52 may be in the order of about 0.2 millimeter in thickness, and the material 54 typically has a refractive index which preferably ranges from about 1.38 to 1.46. The exemplary balloon implant 50 can be crystallized by stretching by elongation or by compressive deformation, in accordance with the procedure described with reference to Figures 13 and 14. Using the teachings of the present invention, it is preferred that at least the skin 52 be made of elastomer crystallizable by stretching. Alternatively, both the skin 52 and the internal elastomeric material 54 may be made of stretch crystallizable elastomer although this is not essential for the practice of the present invention. As will be appreciated by those skilled in the art, the unique functional advantages of the stretch-crystallizable elastomers of the present invention make it possible to manufacture and implant balloon lenses 50 through a small incision in a previously filled configuration. This eliminates the problems and complexities associated with attempting to inflate a balloon lens after implantation. More specifically, the balloon lens 50 of the present invention can be manufactured with controlled dimensions and optical properties prior to implantation. This is particularly convenient for full-size optics that are intended to completely fill the back chamber normally occupied by natural lenses. Because the elastomeric skin 52 crystallizable by stretching of the balloon implant 50 can be deformed significantly, without tearing or permanent deformation, the balloon lens of the present invention can be inserted through relatively small incisions with the confidence that the operation Optical lenses will be appropriate for the particular patients involved. Alternatively, it is also contemplated as being within the scope of the present invention to insert the balloon lens 50 into an empty or deflated configuration. Then, a curable elastomer can be injected to inflate the implant to the desired final configuration. Because the curable internal material 54 is sealed within the biocompatible elastomeric skin 52, the risk of a complicated physiological reaction is avoided. As with the previously described filled mode of the balloon implant 50, the use of biocompatible skin 52 makes it possible to finely adapt the physical properties of the inner material 54 with reduced concern for biocompatibility. In this way, for optical purposes the refractive index of the internal material 54 can be maximized, without concern for the biocompatibility normally associated with direct contact between the internal material 54 and the body tissues or fluids. Alternatively, for non-optical implants which are intended to be placed at different target sites within the patient's body, different physical properties such as viscosity or density can be optimized, with reduced concern for the problems of biocompatibility. Again, it should be emphasized that the scope and teachings of the present invention are not limited to the exemplary embodiments of infra-ocular lenses or lens implants. In accordance with the above, being aware of the broad scope of the present invention, the implants can be manufactured in accordance with the teachings thereof, using any suitable technique known in the art. For example, where appropriate, the implants may be cast, compression molded, injection molded, die cut, or the like. The broad-based manufacturing capability of the present invention is particularly convenient in connection with small implant structures such as exemplary lens embodiments, because the stretch-crystallizable materials of the present invention are suitable for melt-fabrication or molding, the problems associated with the precision coupling of small implant structures can be avoided. As a result, significant portions of the implants of the elastomeric compounds can be formed with minimal complication. Other structural elements of the implants, such as the lens haptics, may be fused in place using conventional fabrication techniques. Using the teachings of the present invention, the crystallizable portion can be formulated by stretching the implants to optimize stretch crystallization and melting temperatures, optical clarity, refractive index, density, resilience, volume, and recovery after stretching as appropriate for the intended purpose of the implant. Due to the elastomeric materials of the present invention do not require cross-linked filters for resistance, these resist permanent deformation when stretched. This allows elastomeric materials to exhibit essentially 100 percent recovery from their original, unstretched configurations, a feature particularly important for light focusing implants. By adapting the formulation of the stretch-crystallizable elastomeric materials, it is possible to finely adapt the stretch crystallization and the melt recovery temperatures to those more suitable for simplified implantation. Because it is very common for contemporary physicians to store lens implants or other implants under refrigerated conditions prior to implantation, it may be preferable to configure the elastomeric implants of the present invention to be crystallized by stretching or freezing in the incision implant configuration. small, at temperatures between 0 ° C and 25 ° C (normal ambient temperatures). Preferably, the melting temperature of the stretch crystallized elastomers will be correspondingly adapted to a point close to the normal body temperature, approximately 37 ° C. Once the stretched crystallized elastomers begin to lose the structural or molecular order induced by the stretching, the melting point will fall relative to the stretched crystallized melting point, so that the implant is able to resume its configuration after implantation . Naturally, biocompatibility and the absence of free monomer that can bleed from elastomeric materials should be formulated within the implants, to avoid subsequent complications. Stretchable crystallizable elastomeric materials typically have melting points that are much lower than normal body temperature. As a result, these have not been practical for use as medical implants because they will not retain easily manipulated, stable, shape-transformed, small incision configurations. On the other hand, where the intended use of the implant includes the light focusing function, known stretch crystallizable materials have been impractical because they are nebulous and lack the proper refractive index to function as a lens implant. Because the natural crystalline lens of the eye has a refractive index in the order of 1.4, it is preferred that the stretch-crystallizable elastomeric materials that are used for lens implants, in accordance with the teachings of the present invention, have indexes of refraction in the order of 1.3 to 1.4 or more. Higher refractive indices will reduce the size, thickness, and volume of the lenses, necessary to obtain the desired optical result. More specifically, the use of materials with a refractive index of 1.4 or more enables the formation of optical lenses having diopters greater than 20. Crystallisable materials by stretching with lower refractive indices can be used to form lenses having diopters in the order of 15 or less. Regardless of whether the implant is intended for light focusing, the stretch crystallizable material must be formulated to finely adapt the crystallized melting point by stretching to a temperature close to, or slightly below, the body temperature. In accordance with the teachings of the present invention, an exemplary stretch-crystallizable elastomeric material can be formed which achieves this result, from homopolymers or copolymers of what are known as F3 monomers. These polymerized exemplary silicone stretch-crystallizable elastomeric materials are exemplified by poly (methyl (3, 3, 3-trifluoropropyl) siloxane). Preferably, these exemplary materials will have a cis / trans ratio ranging from 40/60 to 100/0. This will produce suitable, adaptable, crystallizable melt temperatures. Using the teachings of the present invention, it has been found that the cis form contributes to stretch crystallization, and, therefore, materials of higher melting point can be formed if the cis / trans ratio is 40/60 to 100/0. In accordance with the above, relatively higher stretch crystallized melting point materials can be formed by raising the cis / trans ratio to proportions in the order of 60/40. Where intended use of the stretch-crystallizable elastomeric material is the formation of a light focusing implant, it may be necessary to copolymerize the polymerized monomer F3 with a monomer having a higher refractive index. For example, compounds known in the art as monomers D3 typically have higher refractive indices than monomers F3. The Diphenyl; D3, also known as hexaphenylcyclotrisiloxane is that monomer with a high refractive index. The formation of a copolymer of from 60 percent to 100 percent of an F3 monomer, and between 0 percent and 40 percent of monomer D3, gives those skilled in the art the ability to adapt of the refractive index of the resulting copolymer. The more the monomer D3 is incorporated into the copolymer, the higher the refractive index. As will be appreciated by those skilled in the art, it may be difficult to incorporate more than 40 percent of the D3 monomer into the intended copolymer material.

A further understanding of the present invention will be in accordance with those skilled in the art by a consideration of the following non-limiting examples. These examples illustrate the formulation and chemical manipulation of fine adaptation of the physical properties of stretch-crystallizable elastomeric materials. Before proceeding, it should be emphasized that these examples are illustrative of the principles of the present invention, and are not intended to limit the scope of the invention to exemplary elastomeric materials alone.

Example 1 As a preliminary step in the formation of stretch-crystallizable elastomers. exemplary, in accordance with the teachings of the present invention, a difunctional initiator is prepared for use in the formation of subsequent homopolymers and copolymers. For purposes of illustration, exemplary stretch crystallizable materials are silicone elastomers. In accordance with the foregoing, two (2) grams of diphenylsilandiol were dried at 110 ° C under vacuum for 30 minutes. After cooling to room temperature, and purging with "argon (Ar) gas, 7.5 milliliters (ml) of toluene and 7.5 milliliters of THF were added to obtain a clear solution, then ten (10) microliters were added. (μl) of styrene as an indicator Approximately 8 milliliters of butyl lithium (with a concentration of about 2.5 M in hexane) was added dropwise until the solution turned slightly yellow to form a difunctional initiator solution for use in the formation of exemplary stretch crystallizable elastomers.

Example 2 To form an exemplary stretch-crystallizable elastomeric homopolymer, ten (10) grams (approximately 8 milliliters) of monomer F3, ie, methyl (3,3,3-trifluoropropyl) siloxane, having a cis content of about 60 percent, and a trans content of about 40 percent, to a 125 milliliter reaction flask, was dried at 80 ° C under vacuum for. 30 minutes, and then cooled to room temperature. The cis / trans ratio of 60/40 was chosen for the fine adaptation of the temperature of the melting point of the material, after the crystallization by stretching, to almost normal body temperature. The lower cis / trans ratios produce a material whose melting point would be lower than the normal body temperature. Then one (1) milliliter of THF and 7 milliliters of methylene chloride (CH2C12) were added and stirred for a few minutes. One (1) milliliter of the difunctional initiator of Example 1 was added to initiate the reaction at room temperature under Argon (Ar) gas. After 4 hours the reaction was terminated by the addition of 0.5 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water, dissolving the THF, and precipitating with methanol, more than 8 grams of polymer F3 were collected. The homopolymer was crystal clear with an average molecular weight number, Mn, of 40,000, a polydispersity of 1.1, and a refractive index of 1,383. The F3 homopolymer can be crosslinked by mixing 5 grams of the F3 homopolymer with 2 microliters of platinum (Pt) catalyst (with a platinum concentration of 2.5 percent), 8 microliters of inhibitor, and 45 microliters of tetrequis crosslinker ( dimethylsiloxy) silane, and degassing the viscous liquid by centrifugation. This produced a crosslinked poly (methyl, 3,3,3-trifluoropropyl) siloxane F3 copolymer with a cis / trans ratio of approximately 60/40, and a refractive index of 1383. The silicone elastomer was optically clear with excellent mechanical strength, and exhibited a superior elongation in a direction of more than 600 percent. The polymer was easily crystallized by stretching in a stable transformed form at temperatures below 20 ° C. Heating the crystallized material by stretching to a temperature of about 35 ° C resulted in the material regaining its original shape in a few seconds. This material was used to form plate-style infraocular lenses with an optical zone of 6 millimeters. Stretching these lenses on a long rod, thin, approximately 40 millimeters in length, and cooling the lenses stretched in a cold water bath at approximately 0 ° C to 4 ° C, produced a stable, relatively rigid, rod-shaped implant that was easily manipulated by hand or with forceps. Heating the rod formed by freezing at a temperature between 30 ° C and 40 ° C resulted in the rod returning to its original configuration of the plate intraocular lens in less than five seconds. The optical resolution of the lens remained unchanged through this process. Due to the relatively low refractive index, a practical intraocular lens with a 6-millimeter optical zone using this exemplary material would have an upper diopter limit of about 15. Because most users of infra-ocular lenses require lenses that have diopters in the order of 20 or more, a stretch-crystallizable elastomeric material with a higher refractive index was prepared by copolymerizing the homopolymer of Example 2 with a monomer with a higher refractive index, as described in the following example .

EXAMPLE 3 In order to produce an exemplary stretch crystallizable elastomer having a higher refractive index than the homopolymer of Example 2, eight (8) grams of monomer F3 of Example 2 (with a cis content of about 60) were added. percent, and a trans content of about 40 percent) and 2 grams of diphenyl D3 or hexaphenylcyclotrisiloxane, to a 125 milliliter reaction flask, dried at 110 ° C under vacuum for 30 minutes, and then cooled to 45 ° C. ° C (oil bath temperature). Two (2) milliliters of THF and 14 milliliters of methylene chloride (CH2Cl2) were added to the cooled solution, and stirred for a few minutes, until the diphenyl D3 was completely dissolved. 0.5 milliliters of the difunctional initiator of Example 1 was added to the reaction flask, and the mixture was refluxed at 45 ° C under the argon gas. After 10 hours, the reaction was terminated by cooling to room temperature, and then adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and being precipitated by hexane, 6 grams of the copolymer were obtained. The copolymer was crystal clear with an Mn of 50,000 and a refractive index of 1,408. If desired, the copolymer can be crosslinked by mixing five (5) grams of the copolymer with 2 microliters of a platinum catalyst (with a platinum concentration of 2.5 percent), 8 microliters of inhibitor, and 40 microliters of crosslinker of tetrechis (dimethylsiloxy) silane, and degassing the mixture by centrifugation. As with Example 2, an elastomeric strip was produced by curing the copolymer of Example 3, at a temperature between 100 ° C to 140 ° C for many minutes. This produced an optically transparent, crystal clear crystallizable elastomer exhibiting excellent mechanical strength and superior elongation of more than 600 percent in one direction. The elastomeric material exhibited stable stretch crystallization, and shape transformation at low temperatures of 4 ° C. The heating of the crystallized elastomer by stretching at 35 ° C resulted in the material regaining its original shape within a few seconds. The optical clarity and high refractive index of this elastomeric copolymer crystallizable by exemplary stretching facilitated the production of exemplary infraocular lenses having diopters ranging from 20 to 25. Six infrared plate lenses were molded from the exemplary copolymer elastomer of the Example 3, by molding at 140 ° C for five minutes. Optical resolutions of these experimental lenses were measured using conventional techniques, and it was found that they can be compared with commercially available infraocular lenses made with conventional non-crystallizable materials by stretching. In contrast to the lenses of the prior art, the exemplary stretch crystallizable lenses were able to be stretched to at least five times their original length and, after cooling in an ice water bath, they remained stable in their shape. elongated forms crystallized by stretching. The immersion of the crystallized lenses by stretching in hot water at about 35 ° C resulted in the lenses regaining their original forms immediately. After the shape recovery, the optical resolution of the lenses was measured again and compared with their values prior to the crystallization by stretching. The resolutions after stretching and the recovery resolutions were the same or better than before the lenses were crystallized by stretching. Additionally, a difference of less than 0.2 percent was measured between the dimensions of the lenses before the crystallization by stretching and after the crystallization by stretching. To demonstrate the ability to fine-tune the physical properties of the crystallizable elastomers by stretching through modified formulation techniques, a variation of the copolymer formation protocol of Example 3 was conducted.

Example 4 The reaction of Example 3 above was performed with a reaction time of 21 hours, instead of the original 10 hours. As above, the reaction was terminated by cooling to room temperature, and then adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and precipitation by hexane, 7 grams of copolymer were collected. The copolymer was optically clear with a molecular weight (Mn) of 53,000, and a refractive index of 1418. The higher refractive index makes it possible to use this particular formulation of the crystallizable copolymer by exemplary stretching in infraocular lenses having thinner cross sections and smaller volumes. However, this benefit can be displaced by an associated decrease in mechanical strength and elongation of this exemplary material. After cross-linking this exemplary elastomeric material, using the procedure detailed in Example 3, the polymer exhibited an elongation less than 200 percent. As a result, the benefit obtained with the higher index can be displaced by the inability to crystallize by stretching the material to the degree that is achieved with the copolymer of Example 3. However, the material may be suitable for crystallizable implants by Stretching apart from the infraocular lenses. Further efforts were made in fine-tuning or adjusting the properties of the exemplary stretch crystallizable elastomers of the present invention, by modifying the reaction temperature as follows.

Example 5 The reaction of Example 3 was repeated, and only the oil bath temperature was raised from 45 ° C to 70 ° C. After 10 hours of reaction time, the reaction was terminated by cooling to room temperature and adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and being precipitated by hexane, 7 grams of the copolymer was obtained. The copolymer was crystal clear with a molecular weight (Mn) of 54,000 and a refractive index of 1.40. The crosslinking of the copolymer as above produced an elastomer with a mechanical strength similar to that of Example 3. In accordance with the foregoing, this exemplary stretch crystallizable elastomeric copolymer material exhibited physical and mechanical properties that are suitable for use as medical implants, including infraocular lenses. Additional modifications of the exemplary formulation protocols were provided, by way of the following non-limiting examples, which provide further illustration of the ability to finely modify and adapt the physical and mechanical properties of the exemplary elastomeric materials of the present invention.

Example 6 The reaction of Example 3 was carried out as above, with the reaction temperature decreased from 45 ° C to room temperature, and the reaction time increased from 10 hours to 21 hours. After 21 hours of reaction time, a small amount of the reaction material was removed, and the refractive index was measured to be 1390. The reaction was terminated after 48 hours by cooling to room temperature and adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and being precipitated by hexane, 7 grams of the copolymer was obtained. The copolymer was crystal clear with a molecular weight (Mn) of 36,000 and a refractive index of 1,392. Cross-linking of this material produced a stretch-crystallizable elastomer that exhibited a weaker mechanical strength than that of Example 3. This reduction in refractive index and mechanical strength can render this material unsuitable for use as infra-ocular lens implants. However, it may be appropriate for other implant purposes.

Example 7 The reaction of Example 4 above was performed as above, except that the solvent of methylene chloride was changed to THF. A total of 16 milliliters of THF was used in place of the methylene chloride solvent THF of Example 3. After 2 hours of reaction, the solution became less viscous. The reaction was terminated by cooling to room temperature and adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and being precipitated by methanol, substantially no polymer was obtained.

Example 8 The reaction of Example 7 above was performed as above, with the reaction temperature reduced to room temperature. After 2 hours of reaction, the solution became less viscous. The reaction was terminated by cooling to room temperature and then adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and being precipitated by methanol, substantially no polymer was obtained.

EXAMPLE 9 An elastomeric silicone copolymer, alternative stretch crystallisable, was formed using the protocol of Example 3, with an alternative comonomer by substitution of phenylmethyl D3, or 1, 3, 5-phenyl-2, 4,6-methylis -siloxane by the diphenyl D3. As above, eight (8) grams of the monomer F3 of Example 3 (with a cis content of about 60 percent, and a trans content of about 40 percent) and 2 grams were added. grams of phenylmethyl D3 to a 125 milliliter reaction flask, dried at 80 ° C under vacuum for 30 minutes, and cooled to 45 ° C (oil bath temperature). Two (2) milliliters of THF and 8 milliliters of methylene chloride (CH2Cl) were added and the solution was stirred for a few minutes. 0.5 of the difunctional initiator was added to the reaction flask, and the mixture was refluxed at 45 ° C under the argon gas. After 10 hours of reaction, the solution became viscous and the reaction was terminated by cooling to room temperature and adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and precipitating with methanol, a polymer with a refractive index of 1383 was obtained, indicating that no copolymerization took place.

Example 10 The reaction of Example 9 was carried out as above, with the reaction temperature increased to 110 ° C (oil bath temperature). After 5 hours of reaction, the solution became viscous and the reaction was terminated by cooling to room temperature and adding 0.2 milliliters of vinyl dimethylchlorosilane and triethylamine. After washing with distilled water and toluene, and precipitating with methanol, a polymer with a refractive index of 1383 was obtained, indicating that no copolymerization took place. Those skilled in the art will understand that the foregoing exemplary embodiments of the present invention provide the basis for numerous alternatives and modifications thereto. These other modifications are also within the scope of the present invention. Thus, by way of example, but not limitation, the stretch-crystallizable implants of the present invention can be configured to function as cosmetic implants for reconstructive or augmentation purposes. Those implants would include artificial barbels, cheekbones, noses, ears and other parts of the body, including breasts and penile implants. Similarly, alternative implantation devices may be used to function with those implants in accordance with the principles and teachings of the present invention. In this way, a wide variety of implants can be surgically inserted, and placed through minimal, relatively non-traumatic surgical incisions, in accordance with the foregoing, the present invention is not limited to that which is accurately shown and described in the present invention.

Claims (25)

1. An improved medical implant formed of a stretch crystallizable elastomer, transformable in shape.

The medical implant of claim 1, which also comprises an additional element formed of a non-crystallisable material by stretching.

3. The medical implant of claim 1, wherein the elastomer is a stretch crystallizable silicone.

The medical implant of claim 3, wherein said stretch crystallizable silicone is selected from the group consisting of methyl (3,3,3-trifluoropropyl) siloxane homopolymers and methyl (3,3,3-) copolymers trifluoropropyl) siloxane and hexaphenylcyclotrisiloxane.

The medical implant of claim 4, wherein the methyl (3,3,3-trifluoropropyl) siloxane has a cis / trans ratio ranging from about 40/60 to 100/0.

The medical implant of claim 5, wherein the stretch crystallizable silicone has a crystallization temperature ranging from -100 ° C to 50 ° C.

The medical implant of claim 5, wherein the stretch crystallizable silicone has a crystallization temperature ranging from -20 ° C to 50 ° C, and a recovery temperature ranging from 0 ° C to 50 ° C.

8. The medical implant of claim 5, wherein the stretch crystallizable silicone is optically transparent and has a refractive index ranging from 1.38 to 1.46.

The medical implant of claim 5, wherein the stretch crystallizable silicone is crystallized by stretching at elongations of about 300 percent to 600 percent.

10. The medical implant of claim 9, configured to function as an intraocular lens.

11. An intraocular implant configured for implantation with reduced trauma, and having an optical focusing portion of light formed from a stretch-crystallizable, shape-transformable silicone elastomer having a refractive index ranging from about 1.38 to 1.46. .

The intraocular implant of claim 11, wherein the implant is an intraocular lens.

The intraocular implant of claim 12, wherein the intraocular lens includes a balloon lens.

The intraocular implant of claim 12, further comprising a haptic.

15. The intraocular implant of claim 11, wherein the implant is an implantable contact lens.

16. The intraocular implant of claim 11, wherein the stretch crystallizable silicone is selected from the group consisting of methyl (3, 3, 3-trifluoropropyl) siloxane homopolymers and methyl (3, 3, 3-trifluoropropyl) siloxane and hexaphenylcyclotrisiloxane.

The intraocular implant of claim 16, wherein the methyl (3,3,3-trifluoropropyl) siloxane has a cis / trans ratio ranging from about 40/60 to 100/0.

18. The intraocular implant of claim 16, wherein the stretch crystallizable silicone has a crystallization temperature ranging from -100 ° C to 50 ° C.

The intraocular implant of claim 16, wherein the stretch crystallizable silicone has a crystallization temperature ranging from -20 ° C to 50 ° C, and a recovery temperature ranging from 0 ° C to 50 ° C.

The intraocular implant of claim 16, wherein the stretch crystallizable silicone is crystallized by stretching at elongations of about 300 percent to 600 percent.

21. A method of surgical implantation with reduced trauma comprising the steps of: providing a crystallisable implant by stretching, transformable in shape; crystallize by stretching said implant in a stable, small incision configuration; and inserting the crystallized implant by stretching through a small incision within the body of a patient.

22. The method of surgical implantation of claim 21, which also comprises the additional step of cooling the implant after the step of crystallization by stretching.

23. The method of surgical implantation of claim 21, wherein the stable, small incision implant configuration is an elongated rod or blade.

24. The surgical implantation method of claim 21, which also comprises the additional step of loading the small-incision, stretch-crystallized configuration implant into an implantation device having an exit end, prior to passage. of insertion

25. An apparatus for transforming the shape of a stretch-crystallisable medical implant into a small incision configuration, the apparatus comprising: a female mold which is provided with a longitudinal receiving groove defining an elongate mold cavity at its base; and a compression piston that is provided with a longitudinally projecting guide member, having a mating face, the guide member sized to be slidably received in engagement gear in the receiving groove to complete the configuration of said cavity printed.