US20140275794A1

US20140275794A1 - Mechanical Gel Surgical Access Device

Info

Publication number: US20140275794A1
Application number: US14/211,296
Authority: US
Inventors: Matthew M. Becerra; Jeremy J. Albrecht
Original assignee: Applied Medical Resources Corp
Current assignee: Applied Medical Resources Corp
Priority date: 2013-03-15
Filing date: 2014-03-14
Publication date: 2014-09-18
Also published as: CA2902201A1; EP2967512A1; KR20150127060A; US20200008792A1; EP3603534A1; AU2014228334A1; KR102300866B1; ES2768612T3; US11471142B2; EP2967512B1; WO2014143656A1; AU2014228334B2; JP2016512725A

Abstract

A mechanical cap ring/gel pad assembly useful in surgical access devices and methods for making the same, wherein the cap ring and the gel pad are formed separately and then mechanically attached to form a strong seal without the need for heating, solvents or adhesives.

Description

BACKGROUND

1. Technical Field
This application is generally directed to a gel surgical access device useful in minimally invasive surgical procedures, and, more particularly, to improved methods of manufacturing such devices.
2. Description of the Related Art
Surgical devices incorporating gel pads have been described in the art. For example, hand access devices incorporating gel pads and methods for making the same are described in U.S. Pat. No. 7,736,306, U.S. Pat. No. 7,878,974 and U.S. Pat. No. 7,749,415, the contents of which are hereby incorporated by reference as if set forth in full herein. These describe a device in which a cap containing a gel pad may be attached to a wound retractor, to provide sealable hand access into a body cavity while maintaining pneumoperitoneum. A natural orifice surgery system has also been described in U.S. Publ. No. 2012/0095297, the contents of which is hereby incorporated by reference as if set forth in full herein. In this publication, a device is described in which a cap containing a gel pad may be attached to an access device disposed within a natural body orifice.
These gel caps generally incorporate gel pads enclosed within a cap ring, which may be attached to a retractor or other access device during the surgical procedure. These cap rings are often formed from a polycarbonate or other plastic materials. During use, pressure is place on the gel pad as trocars, hands, or other instruments are passed through the gel. It may also be important to maintain pneumoperitoneum during instrument/hand exchange. Accordingly, it is important for the gel pad and the cap ring to form a secure bond and seal.
Current manufacturing practices usually cast the gel pad with the cap ring to form the bond between them. The gel casting process is done in an oven at elevated temperatures. However, due to the presence of the polycarbonate cap ring, oven temperatures must be kept lower, and the assembly heated longer, than would be necessary if the gel was cooked alone. Moreover, the polycarbonate rings require complex molds and braces to prevent deformation during the cooking process and the resulting bond between gel pad and cap ring can vary between lots. In addition, the elevated temperatures in the oven may be detrimental to the mechanical properties of the polycarbonate ring. Finally, oil in the gel material extrudes onto the cap ring during cooking, and significant cleaning must be performed once the gel pad/cap ring assembly is removed from the oven.
Some of these problems can be solved by preparing the gel pad separately from the cap ring. For example, the gel pad can be molded and then attached to the cap ring with an adhesive, such as cyanoacrylate adhesives, or using solvent welding. Alternatively, the gel pad can be cast slightly larger than the cap ring, then compression molded into the ring and heated to bond. All of these techniques involve additional labor steps, the addition of adhesives or solvents, and/or at least some heating of the cap ring with the gel pad, which will then necessitate significant cleaning of the assembly.
What is needed, therefore, is a gel pad/cap ring assembly wherein the two components are formed separately and then mechanically attached to form a strong seal without the need for heating, solvents or adhesives. With such a manufacturing process, the gel pad can be cooked at significantly higher temperatures and for shorter periods of time, enabling rapid manufacturing methods such as injection molding. The plastic cap rings would no longer be subjected to elevated oven temperatures, eliminating the risk of deformation, and no cleaning to remove oil would be required. The mechanical closure mechanism attaching gel pad to cap ring would serve as bond and seal, no longer varying between lots, and simplified cooking molds for the gel pad could be used, eliminating the need to brace the polycarbonate ring within the mold.

SUMMARY OF THE INVENTION

The invention is directed to surgical device having a mechanical gel pad/cap ring assembly, and to methods for manufacturing the same.
In one embodiment, the invention is directed to a method of making a gel cap, comprising providing a split cap ring having a first end and a second end, the cap ring defining a channel on its inner surface, the first end having a pin, and the second end having a boss complementary to the pin, providing a gel pad sized and configured to fit within the split ring cap, disposing the split cap ring around the gel pad, and inserting the pin into the boss to seal the gel pad within the split cap ring.
In another embodiment, the invention is directed to a method of making a gel cap, comprising providing a double split cap ring having a first end, a second end, a third end and a fourth end, the cap ring defining a channel on its inner surface, the first and third ends each having a pin, and the second and fourth ends each having a boss complementary to the pin, providing a gel pad sized and configured to fit within the double split ring cap, disposing the split cap ring around the gel pad, and inserting the pin of the first end into the boss of the second end and the pin of the third end into the boss of the fourth end to seal the gel pad within the double split cap ring.
In another embodiment, the invention is directed to a method of making a gel cap, comprising providing a horizontally split cap ring having a proximal piece and a distal piece, the cap ring defining a channel on its inner surface, the proximal piece having at least one boss and at least one pin on its distal side, the distal piece having at least one boss and at least one pin on its proximal side, providing a gel pad sized and configured to fit within the horizontally split cap ring, placing the gel pad on the proximal surface of the distal cap ring piece, placing the proximal cap ring piece on the gel pad such that the pin is aligned with the boss on the distal piece and the boss is aligned with the pin on the distal piece, and inserting the pin into the boss to seal the gel pad within the horizontally split cap ring. In another embodiment, the cap ring may have a compression bump disposed on the inner surface of the channel.
In other embodiments, the invention is directed to a method of making a gel cap according to any of the previous methods, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.
In other embodiments, the invention is directed to a gel cap made by any of the processes described herein.
These and other features and advantages of the invention will become more apparent with a discussion of embodiments in reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an embodiment of a mechanical gel surgical access device; FIG. 1B is an exploded view of the mechanical gel surgical access device of FIG. 1A.

FIG. 2A is a perspective cross-sectional view of an embodiment of a mechanical gel surgical access device; FIG. 2B is a side view of the mechanical gel surgical access device of FIG. 2A; FIG. 2C is an exploded view of the mechanical gel surgical access device of FIG. 2A.

FIG. 3A is an exploded perspective view of an embodiment of a mechanical gel surgical access device; FIG. 3B is an exploded cross-sectional side view of the mechanical gel surgical access device of FIG. 3A. FIG. 3C is a perspective cross-sectional view of the mechanical gel surgical access device of FIG. 3A.

FIG. 4A is an exploded cross-sectional side view of another embodiment of a mechanical gel surgical access device, showing a compression bump; FIG. 4B is a cross-sectional side view of the mechanical gel surgical access device of FIG. 4A.

FIG. 5A is an exploded cross-sectional side view of another embodiment of a mechanical gel surgical access device, showing an internal o-ring molded into the gel pad; FIG. 5B is a cross-sectional side view of the mechanical gel surgical access device of FIG. 5A.

FIG. 6 is perspective cross-sectional view of an embodiment of a mechanical gel surgical access device having pins and bosses penetrating the gel pad.

Similar components have similar reference numbers throughout.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

As used herein, mechanical gel surgical access device comprises a “gel cap” that incorporates a gel pad coupled to a cap ring. Preferably, the attachment between the gel pad and the cap ring forms a gas-tight seal. Optionally, the gel cap incorporates other features, such as attachment mechanisms for retractors and other access devices, as has been described in U.S. Pat. No. 7,736,306, U.S. Pat. No. 7,878,974, U.S. Pat. No. 7,749,415, and U.S. Publ. No. 2012/0095297, the contents of which are hereby incorporated by reference as if set forth in full herein.
The gel pad may be made from an elastomeric gel, some of which have been described in U.S. Pat. No. 7,473,221, the content of which is also hereby incorporated by reference as if set forth in full herein.
The gel can be prepared by mixing a triblock copolymer with a solvent for the midblocks. The endblocks are typically thermoplastic materials such as styrene and the midblocks are thermoset elastomers such as isoprene or butadiene, e.g., Styrene-Ethylene-Butylene-Styrene (SEBS). In one aspect, the solvent used is mineral oil. Upon heating this mixture or slurry, the midblocks are dissolved into the mineral oil and a network of the insoluble endblocks forms. The resulting network has enhanced elastomeric properties over the parent copolymer. In one aspect, the triblock copolymer used is KRATON G1651, which has a styrene to rubber ratio of 33/67. Once formed, the gel is substantially permanent and, by the nature of the endblocks, processable as thermoplastic elastomers henceforward. The mixture or slurry has a minimum temperature at which it becomes a gel, i.e., the minimum gelling temperature (MGT). This temperature, in one aspect, corresponds to the glass transition temperature of the thermoplastic endblock plus a few degrees. For example, the MGT for the mixture of KRATON G1651 and mineral oil is about 120° C. When the slurry reaches the MGT and the transformation to a gel state takes place, the gel becomes more transparent, thereby providing means for visually confirming when the transformation of the slurry to the gel state is substantially complete and that the gel may be cooled. In addition to triblocks, there are also diblock versions of the materials that may be used where Styrene is present at only one end of the formula, for example, Styrene-Ethylene/Butylene (SEB).
For a given mass of slurry to form into a complete gel, the entire mass of the slurry is heated to the MGT and remains heated at the MGT for sufficient time for the end blocks to form a matrix of interconnections. The slurry will continue to form into gel at temperatures above the MGT until the slurry/gel reaches temperatures at which the components within the slurry/gel begin to decompose or oxidize. For example, when the slurry/gel is heated at temperatures above 250° C., the mineral oil in the slurry/gel will begin to be volatile and oxidize. Oxidizing may cause the gel to turn brown and become oily.
The speed at which a given volume of slurry forms a gel is dependant on the speed with which the entire mass of slurry reaches the MGT. Also, with the application of temperatures higher than the MGT, this speed is further enhanced as the end block networks distribute and form more rapidly.
The various base formulas may also be alloyed with one another to achieve a variety of intermediate properties. For example, KRATON G1701X is a 70% SEB 30% SEBS mixture with an overall Styrene to rubber ratio of 28/72. It can be appreciated that an almost infinite number of combinations, alloys, and Styrene to rubber ratios can be formulated, each capable of providing advantages to a particular embodiment of the invention. These advantages will typically include low durometer, high elongation, and good tear strength.
It is contemplated that the gel material may also include silicone, soft urethanes and even harder plastics that might provide the desired sealing qualities with the addition of a foaming agent. The silicone material may be of the types currently used for electronic encapsulation. The harder plastics may include PVC, Isoprene, KRATON neat, and other KRATON/oil mixtures. In the KRATON/oil mixture, oils such as vegetable oils, petroleum oils and silicone oils may be substituted for the mineral oil.
Any of the gel materials contemplated could be modified to achieve different properties such as enhanced lubricity, appearance, and wound protection. Additives may be incorporated directly into the gel or applied as a surface treatment. Other compounds may be added to the gel to modify its physical properties or to assist in subsequent modification of the surface by providing bonding sites or a surface charge. Additionally, oil based colorants may be added to the slurry to create gels of different colors.
In one aspect, the mixture/slurry used with the various embodiments of the caps that are described herein are composed of about 90% by weight of mineral oil and about 10% by weight of KRATON G1651. From a thermodynamic standpoint, this mixture behaves similar to mineral oil. Mineral oil has a considerable heat capacity and, therefore, at about 130° C. it can take 3 or 4 hours to heat a pound of the slurry sufficiently to form a homogeneous gel. Once formed, the gel can be cooled as quickly as practical with no apparent deleterious effects on the gel. This cooling, in one aspect, is accomplished with cold-water immersion. In another aspect, the gel may be air-cooled. Those familiar with the art will recognize that other cooling techniques that are well known in the art may be employed and are contemplated as within the scope of the present invention.
Many of the properties of the KRATON/oil mixture will vary with adjustments in the weight ratio of the components. In general, the greater the percentage of mineral oil the less firm the mixture; the greater the percentage of KRATON, the more firm the mixture. If the resultant gel is too soft it can lead to excessive tenting or doming of the gel cap during surgery when a patient's abdominal cavity is insufflated. Additionally, if the gel is too soft it might not provide an adequate seal. However, the gel should be sufficiently soft to be comfortable for the surgeon while simultaneously providing good sealing both in the presence of an instrument and in the absence of an instrument.
If the slurry is permitted to sit for a prolonged period of time, the copolymer, such as KRATON, and the solvent, such as mineral oil, may separate. The slurry may be mixed, such as with high shear blades, to make the slurry more homogeneous. However, mixing the slurry may introduce or add air to the slurry. To remove air from the slurry, the slurry may be degassed. In one aspect, the slurry may be degassed in a vacuum, such as within a vacuum chamber. In one aspect, the applied vacuum may be 0.79 meters (29.9 inches) of mercury, or about 1.0 atmosphere. The slurry may be stirred while the slurry is under vacuum to facilitate removal of the air. During degassing within a vacuum, the slurry typically expands, then bubbles, and then reduces in volume. The vacuum may be discontinued when the bubbling substantially ceases. Degassing the slurry in a vacuum chamber reduces the volume of the slurry by about 10%. Degassing the slurry helps reduce the potential of the finished gel to oxidize.
Degassing the slurry tends to make the resultant gel firmer. A degassed slurry composed of about 91.6% by weight of mineral oil and about 8.4% by weight of KRATON G1651, an eleven-to-one ratio, results in a gel having about the same firmness as a gel made from a slurry that is not degassed and that is composed of about 90% by weight of mineral oil and about 10% by weight of KRATON G1651, a nine-to-one ratio.
Mineral oil is of a lighter density than KRATON and the two components will separate after mixing, with the lighter mineral oil rising to the top of the container. This separation may occur when attempting to form static slurry into gel over a period of several hours. The separation can cause the resulting gel to have a higher concentration of mineral oil at the top and a lower concentration at the bottom, e.g., a non-homogeneous gel. The speed of separation is a function of the depth or head height of the slurry being heated. The mass of slurry combined with the head height, the temperature at which the gel sets and the speed with which the energy can be transferred to the gel, factor into the determination or result of homogeneous gel versus a non-homogeneous gel.
In an embodiment for manufacturing a gel pad 2, the gel slurry is poured into a mold cavity of a casting mold. Embodiments of the mold comprise a material with sufficient heat dissipation properties, for example, at least one of aluminum, copper, and brass. Those skilled in the art will recognize that other mold materials with lower heat dissipation properties will produce acceptable parts in some embodiments. Furthermore, some embodiments of the mold comprise active cooling elements, for examples, channels through which coolants are pumped.
The mold cavity is filled with a desired amount of the triblock copolymer/mineral oil slurry such that the slurry fills the mold to the desired height. In some embodiments, the slurry is preheated, for example, to about 52° C. (125° F.), which facilitates a complete filling of the mold cavity by the slurry, thereby reducing the probability of voids in the gel. Preheating the slurry to a temperature below the MGT reduces the viscosity of the slurry and allows the slurry to flow more easily. As stated above, some embodiments of the slurry are degassed in a vacuum before casting. In some embodiments, the slurry is also degassed after it is filled in the mold cavity to remove any air that may have been introduced during the filling of the mold cavity, as well as to facilitate flow of the slurry into voids in the mold. The mold and slurry are heated, for example, in an oven, until the slurry reaches a temperature of about 120° C. to about 150° C.
When the transformation of the slurry into a gel is complete, for example, when the temperature of the gel pad reaches about 150° C., the gel pad is cooled, for example, by air-cooling, cold-water immersion, or another suitable method. At 150° C. the gel pad is soft and easily distorted. Distortions in the gel pad present during cooling would be set after cooling. Accordingly, in some embodiments, the gel pad is cooled within the mold, thereby reducing the likelihood of distorting the gel pad. Factors affecting the cooling time include the size and configuration of the mold, the quantity of gel, temperature and quantity of cooling medium, the properties of the cooling medium, and the mold material. As an example, the cooling time for a particular gel pad may be about two (2) hours for air cooling and about fifteen (15) minutes for water cooling. Whether cooling with air or water, the final properties of the gel are substantially the same. The gel pad is typically cooled to about ambient room temperature, but may be cooled to a lower temperature if desired. At about 0° C., the gel hardens, which is useful, for example, in secondary operations such as when coupling separately manufactured gel pads and cap rings. The gel pad may be removed from the mold at any time after the gel has set.
When removed from the mold, the gel pad typically has a tacky surface. Coating the gel pad with a powder, such as cornstarch, substantially reduces or eliminates the tackiness of the cured gel pad.
The cap ring in some embodiments comprises a polymer. Examples of suitable polymers include, at least one of polyethylene (PE), low density polyethylene (LDPE), high density polyethylene (HDPE), ultra high molecular weight polyethylene (UHMWPE), polycarbonate, thermoplastic elastomers (DYNAFLEX®, GLS Corp.; KRATON®, Kraton Polymers), polyphenylene oxide (PPO), polystyrene, and the like. The polymer component of the cap ring is fabricated by any suitable method, including injection molding, melt casting, blow molding, and the like.
In FIGS. 1A and 1B, a mechanical gel surgical access device 1 according to one aspect of the present invention is shown. The device includes a gel pad 2 and a cap ring 4. Some embodiments of the cap ring 4 comprise a substantially cylindrical ring comprising a proximal portion, a distal portion, and a longitudinal axis extending from the proximal portion to distal portions. The cap ring 4 may also define a channel 6 circumscribed along the interior of the cap ring. In other embodiments, the cap ring 4 has another shape or footprint, for example, oval. As shown in FIG. 1A, the gel pad 2 is disposed within the interior of the cap ring 4.
The cap ring 4 is formed from a first piece and a second piece, each piece having one end with a pin 8 and a second end with a boss 10, adapted to receive the pin and form a tight snap fit. To assemble the gel cap, each piece of the cap ring is placed around the gel pad such that the pin 8 on the first piece is snapped into the boss 10 of the second piece and pin 8 of the second piece is snapped into boss 10 of the first piece, compressing the gel pad and forcing gel into the channel 6 of the cap ring, mechanically locking the cap ring 4 and the gel pad 2 together.
In FIGS. 2A, 2B and 2C, another mechanical gel surgical access device 1 according to one aspect of the present invention is shown. This embodiment is similar to that of FIG. 1, except that a circular ring 12 is disposed within the gel pad 2, along the periphery of the pad. A gel pad with such a ring may be formed in a variety of ways.
In one embodiment, the gel slurry can be poured into a puck-shaped mold, and an inner ring inserted into the gel slurry to create an undercut once the gel slurry is cured. After curing, the inner ring is removed, leaving an internal groove around the periphery of the gel pad 2. The circular ring 12 is then inserted into the groove and the gel pad assembled into the cap ring.
In another embodiment of a method for manufacturing a gel pad with a circular ring, the circular ring 12 is placed into a mold that includes a negative space in the desired shape of the gel pad 2. The circular ring 12 is supported on pins to raise it above the bottom of the mold but still below the top of the mold. Sufficient uncured gel is then added to the mold to fill the mold, covering the circular ring. After the gel cures, the pad is removed from the mold with the circular ring encased inside the gel.
In still another embodiment of a method for manufacturing a gel pad with a circular ring, the circular ring 12 is suspended between pin holders in an injection molding cavity. These pins hold the circular ring in position while the gel slurry is injected into the cavity. The gel is then cured using standard injection molding techniques.
Preferably, the circular ring is formed from a metal such as stainless steel, although nylon or high temperature plastics may be used as well. If bonding between the circular ring and the gel is desired, the circular ring may be coated or sleeved with polycarbonate, nylon, KRATON®, polyethylene and the like.
To assemble the a mechanical gel surgical access device 1 of FIG. 2, shown in cross-section, each half of the cap ring is placed around the gel pad 2 and pressed together, preferably with a pin and boss snap fit such as described for FIG. 1, compressing the gel pad 2 and forcing the circular ring 12 and the encasing gel into the channel 6 of the cap ring 4, mechanically locking the cap ring 4 and the gel pad 2 together.
In another embodiment of a mechanical gel surgical access device, the cap ring 4 is formed as a single piece, with a C-channel 6 and a single split opening. The cap ring of this embodiment is semi-compliant so that the two ends of the ring can be spread apart sufficiently to place the ring around the gel pad. The two ends are then connected by snap fits, latches, adhesive, welding or some other method to secure the gel pad within the cap ring.
FIGS. 3A and 3B illustrate another embodiment of a mechanical gel surgical access device. In this embodiment, the cap ring is split horizontally into two circular pieces, a proximal piece 16 and a distal piece 18. Each of the two pieces 16 and 18 circumscribe a shaped channel 14, in this example an L-shaped channel. The proximal piece 16 has pins 20 and bosses 22 disposed along its distal side, while the distal piece 18 has pins 20 and bosses 22 disposed along its proximal side. These pins and bosses are arranged in complementary fashion, such that when the two pieces of the cap ring are pressed together, the bosses of one piece receive the pins of the other piece in a press fit. To assemble the mechanical surgical access device, the gel pad 2 is sandwiched between the proximal and distal pieces of the cap ring 16, 18, with the gel pad filling the channels 14 of both pieces. The gel pad is held in place by the connection of the pins and bosses. A perspective view of a cross-section of the assembled cap ring/gel pad of the embodiment of FIG. 3A is shown in FIG. 3C.
A variation of the embodiment of FIG. 3 is shown in FIGS. 4A and 4B. In this embodiment, the cap ring is split horizontally into two circular pieces, a proximal piece 24 and a distal piece 26, each of which circumscribes a channel 27 on the interior of the ring. Each piece has a projection, or compression bump 28, extending radially around the inner portion of the ring. The compression bump 28 of the proximal piece 24 extends in the distal direction while the compression bump 28 of the distal piece 26 extends in the proximal direction. When the two pieces are snap fitted together with their respective pins 20 and bosses 22, the channels 27 of the pieces define a channel 29 with the compression bumps 28 forming a narrow region in the entrance of the channel To assemble the mechanical surgical access device, the gel pad 2 is sandwiched between the proximal and distal pieces of the cap ring 24, 26, with the gel pad filling the channel 29. The gel pad is held in place by the connection of the pins and bosses in the cap ring and is further sealed and secured by the pressure of the compression bumps 28.
A variation of the embodiment of FIG. 4 is shown in FIGS. 5A and 5B. In this embodiment, the gel pad 30 is formed with a circular ring 32 disposed along the periphery of the gel pad as described above. When assembled, as shown in FIG. 5B, the circular ring 32, along with the surrounding gel, is enclosed in channel 29. Compression bumps 28 further secure and seal the gel pad with the cap ring. Preferably, the circular ring is formed from a metal such as stainless steel, although nylon or high temperature plastics may be used as well. If bonding between the circular ring and the gel is desired, the circular ring may be coated or sleeved with polycarbonate, nylon, KRATON®, polyethylene and the like.
FIG. 6 illustrates another embodiment of a mechanical gel surgical access device. In this embodiment, shown in cross-section, the gel pad 34 is formed with a series of holes on the perimeter of the pad. These holes may be formed during casting, by providing posts or pins in the mold to displace gel slurry, or may be added after the gel pad is cured. The holes form tunnels through which posts 40 on the interior surfaces of the proximal piece 36 and the distal piece 38 of the cap ring may pass. To assemble the mechanical gel surgical access device, the gel pad is disposed onto the distal piece of the cap ring, with the posts 40 of the distal piece extending up through a portion of the peripheral holes of the gel pad. The proximal piece of the cap ring is then placed on top of the gel pad, with the posts of the proximal piece extending down through the remaining holes of the gel pad. The two pieces of the cap ring are then secured together, preferably by snap fitting pins and bosses (not shown), with the gel pad securely held between them.
While certain embodiments have been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope thereof as defined by the following claims.

Claims

What is claimed is:

1. A method of making a gel cap, comprising:

providing a split cap ring having a first end, a second end, and a means for connecting the first end to the second end, the cap ring defining a channel on its inner surface,

providing a gel pad sized and configured to fit within the split cap ring,

disposing the split cap ring around the gel pad, and

connecting the first end to the second end to thereby secure the gel pad within the cap ring.

2. The method of claim 1, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.

3. The method of claim 1, wherein the means for connecting comprises a snap fit.

4. The method of claim 1, wherein the means for connecting comprises a latch.

5. The method of claim 1, wherein the means for connecting comprises a boss and a pin.

6. The method of claim 1, wherein the means for connecting comprises an adhesive.

7. The method of claim 1, wherein the means for connecting comprises a weld.

8. A gel cap made by the process of claim 1.

9. A method of making a gel cap, comprising:

providing a cap ring comprising a first piece having a first end and a second end, a second piece having a third end and a fourth end, and means for connecting the first end to the third end and the second end to the fourth end, the cap ring defining a channel on its inner surface,

providing a gel pad sized and configured to fit within the cap ring,

disposing the cap ring around the gel pad, and

connecting the first end to the third end and the second end to the fourth end to thereby seal the gel pad within the cap ring.

10. The method of claim 9, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.

11. The method of claim 9, wherein the means for connecting comprises a snap fit.

12. The method of claim 9, wherein the means for connecting comprises a latch.

13. The method of claim 9, wherein the means for connecting comprises a boss and a pin.

14. The method of claim 9, wherein the means for connecting comprises an adhesive.

15. The method of claim 9, wherein the means for connecting comprises a weld.

16. A gel cap made by the process of claim 9.

17. A method of making a gel cap, comprising:

providing a horizontally split cap ring having a proximal piece, a distal piece, and means for connecting the proximal piece to the distal piece, the cap ring defining a channel on its inner surface,

providing a gel pad sized and configured to fit within the horizontally split cap ring,

placing the gel pad between the proximal piece and the distal piece, and

connecting the proximal piece to the distal piece to thereby seal the gel pad within the horizontally split cap ring.

18. The method of claim 17, further comprising providing a compression bump disposed on the inner surface of the channel

19. The method of claim 17, further comprising providing a circular ring disposed within the gel pad around the periphery of the gel pad.

20. The method of claim 17, wherein the means for connecting comprises a snap fit.

21. The method of claim 17, wherein the means for connecting comprises a latch.

22. The method of claim 17, wherein the means for connecting comprises a boss and a pin.

23. The method of claim 17, wherein the means for connecting comprises an adhesive.

24. The method of claim 17, wherein the means for connecting comprises a weld.

25. A gel cap made by the process of claim 17.