US20060129123A1 - Transcutaneous inserter for low-profile infusion sets - Google Patents

Abstract

A low-profile inserter for an angled infusion set comprises an inserter housing having a bottom wall, a retainer slidably connected to the inserter housing for movement between retracted and extended positions in a direction substantially parallel with the bottom wall, and a base member connected to the inserter housing. The retainer is adapted to releasably receive a cannula assembly, including a cannula connected to a cannula housing. The base member has a lower surface that is adapted to contact a skin outer surface. The lower surface and bottom wall together form an acute angle. With this arrangement, the cannula can be inserted subcutaneously at the acute angle with respect to the skin outer surface.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• This application is a continuation of U.S. application Ser. No. 10/024,894, filed Dec. 18, 2001, which claims the benefit of U.S. application Ser. No. 60/256,573, filed Dec. 19, 2000.
BACKGROUND OF THE INVENTION
• This invention relates to medical devices, and more particularly to an automatic inserter for installing an angled or low-profile infusion set in the skin of a person to subcutaneously administer medication or other substances beneficial to health.
• Frequent or continuous subcutaneous injection of medication such as insulin is often accomplished through the use of an infusion set or injection port which may remain in place for several days. In the case of frequent injections, the infusion set reduces the need to constantly puncture the skin, thereby minimizing the risk of infection and the formation of scar tissue. For continuous subcutaneous delivery of medication through portable insulin pumps or the like, an infusion set is often used to provide a method of temporarily detaching the pump and fluid line for activities such as dressing or bathing. It is also desirable in this instance to detach the fluid line from the pump as close to the injection site as possible, thereby leaving a relatively small component attached to the body which minimizes any interference during dressing, bathing or other activities.
• Angled infusion sets, such as disclosed in my copending U.S. patent application Ser. No. 09/625,245 filed on Jul. 25, 2000, now U.S. Pat. No. 6,572,586, the disclosure of which is herein incorporated by reference, are especially advantageous due to their low profile during use. See also U.S. Pat. No. 5,522,803 issued to Tiessen-Simoney on Jun. 4, 1996. Such devices include a manual inserter with a handle and an introducer needle that attach to a cannula housing. A self-adhesive pad on the bottom surface of the cannula housing secures the housing to the skin of a person. To insert the infusion set, the user grasps the handle with one hand while pinching a fold of skin between the thumb and forefinger of the other hand. The introducer needle together with the outer end of the cannula are then pushed by the user into the fold of skin. The introducer needle is removed from the cannula housing leaving the cannula inserted in the subcutaneous layer. The housing is then adhesively secured to the skin. A tubing connector from an insulin pump can then be connected to the cannula housing to deliver insulin or other substances to the subcutaneous layer.
• While this process is relatively straightforward for more experienced persons, it does require manual dexterity. In addition, the cannula may become kinked during an improper installation and impede the flow of insulin, or may be positioned in an improper skin layer. Surrounding tissue may also be damaged during attempts to correctly position the cannula, causing added pain and trauma to a user. Many users prefer to avoid the trauma associated with self-inserting the introducer needle and cannula into their bodies.
• Accordingly, it would be desirous to provide an automatic inserter for angled or low-profile infusion sets, thereby assuring the correct placement of the cannula in the subcutaneous layer at the correct angle while minimizing the trauma associated with cannula installation.
SUMMARY OF THE INVENTION
• According to one aspect of the invention, a low-profile inserter for an angled infusion set comprises an inserter housing having a bottom wall, a retainer slidably connected to the inserter housing for movement between retracted and extended positions in a direction substantially parallel with the bottom wall, and a base member connected to the inserter housing. The retainer is adapted to releasably receive a cannula assembly, including a cannula connected to a cannula housing. The base member has a lower surface that is adapted to contact an outer skin surface. The lower surface and bottom wall together form an acute angle. With this arrangement, the cannula can be inserted subcutaneously at the acute angle with respect to the outer skin surface.
• According to a further aspect of the invention, an inserter for an infusion set comprises an inserter housing, and a retainer slidably connected to the inserter housing for movement between retracted and extended positions. The retainer is adapted to releasably receive the cannula assembly. A biasing member is connected between the retainer and the inserter housing for biasing the retainer toward the extended position. A first release lever is pivotally mounted to the inserter housing. The first release lever includes a first end portion that is exposed through the housing for manipulation by an operator and a second end portion for engagement with the retainer to thereby hold the retainer in the retracted position. In this manner, pivotal movement of the first release lever in a first rotational direction causes disengagement of the second end portion and the retainer to thereby release the retainer.
BRIEF DESCRIPTION OF THE DRAWINGS
• The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:
• FIG. 1 is a side elevational view of a low-profile inserter assembly according to the invention in a retracted or cocked position;
• FIG. 2 is a side elevational view of the inserter assembly ofFIG. 1 in an extended position with an insertion needle and cannula inserted in the skin (shown in cross section);
• FIG. 3 is a front elevational view of the inserter assembly;
• FIG. 4 is top plan view in partial cross section of the inserter assembly;
• FIG. 5 is an enlarged cross sectional view of the inserter assembly taken along line5-5 ofFIG. 3;
• FIG. 6 is an enlarged cross sectional view of a portion of the inserter assembly taken along line6-6 ofFIG. 5;
• FIG. 7 is an isometric view of a low-profile inserter assembly according to a second embodiment of the invention;
• FIG. 8 is a top plan view of the inserter assembly second embodiment;
• FIG. 9 is top plan view in partial cross section of a low-profile inserter assembly according to a third embodiment of the invention;
• FIG. 10 is an enlarged cross sectional view of the inserter assembly second embodiment taken along line10-10 ofFIG. 9;
• FIG. 11 is an enlarged cross sectional view of a portion of the inserter assembly taken along line11-11 ofFIG. 10;
• FIG. 12 is a side elevational view of a low-profile inserter assembly according to a fourth embodiment of the invention;
• FIG. 13 is a top plan view of the inserter assembly fourth embodiment; and
• FIG. 14 is a front elevational view in partial cross section of the inserter assembly fourth embodiment.
• It is noted that the drawings are intended to represent only typical embodiments of the invention and therefore should not be construed as limiting the scope thereof. The invention will now be described in greater detail with reference to the drawings, wherein like parts throughout the drawing figures are represented by like numerals.
DETAILED DESCRIPTION OF THE INVENTION
• Referring now to the drawings, and toFIGS. 1-3 in particular, a low-profile inserter assembly10 according to the invention includes ahousing12 with anupper housing portion14 connected to alower housing portion16. An angled alignment guide in the form of a triangular-shaped base18 is preferably integrally formed with thelower housing portion16 and includes alower surface20 that is adapted to contact anouter surface22 ofskin24 during use. Thelower surface20 extends at anacute angle 0 with respect to abottom wall25 of thelower housing portion16 so that aninsertion needle27 andcannula26 of a low-profile cannula housing28 placed in theinserter assembly10 can be inserted into theskin24 at the proper angle. Theangle 0 is in the range of approximately 10° to 40°, and preferably in the range of 15° to 35°, depending on the particular configuration of thecannula housing28 to be installed. In one preferred embodiment, theangle 0 is approximately 30° to accommodate a cannula housing and accompanying cannula that will extend into the subcutaneous layer at approximately 30° with respect to the skinouter surface22. The housing portions may be constructed of any suitable material, and can be retained together through screws23 (FIG. 5), interlocking tabs, adhesive, heat-staking, or a combination thereof, or any other well-known fastening means.
• With reference now toFIGS. 4-6, aretainer30 is slidably mounted in thehousing12 between theupper housing portion14 and thelower housing portion16. Theretainer30 includes amain body40 and a pair of side flanges42 (only one shown inFIG. 6) that extend laterally from the main body and a pair of bottom flanges44 (only one shown inFIG. 6) that extend downwardly from the main body. A pair of spacedguide ribs32 extend downwardly from anupper wall34 of theupper housing portion14. Eachguide rib32 includes alower surface36 that slidably contacts anupper surface46 of one of theside flanges42. A pair of spaced shoulders48 (only one shown inFIG. 6) are formed at the intersection of thebottom wall25 andopposite side walls52 of thelower housing portion16. Eachbottom flange44 includes aside surface50 and alower surface54 that slidably contact ashoulder side surface56 and aninner surface58 of thebottom wall25, respectively, to guide sliding movement of theretainer30 in a substantially linear direction between a retracted position (FIG. 1) and an extended position (FIG. 2).
• As best shown inFIG. 5, an infusion setrelease lever60 is pivotally connected to a forward end of theretainer30 at a pivot joint64. The pivot joint64 may include fingers (not shown) on thelever60 that extend in opposite directions and fit into opposed depressions (not shown) in theretainer30. Arelease button66 is formed at a forward end of thelever60 for manipulation by a user. A downwardly-extendingcatch68 is formed on thelever60 rearwardly of the pivot joint64 and normally seats against adepression70 in the top of a handle portion72 of thecannula housing28. A lower rampedsurface62 extends from therelease button66 to thecatch68 to facilitate connection of thecannula housing28 to theretainer30. Aslot74 is formed in the forward end of theretainer30 for receiving the handle portion72. A slot78 (FIG. 4) is also formed in thehousing12 between theupper housing portion14 and thelower housing portion16 to accommodate an adhesive-backedmounting pad80 associated with thecannula housing28 since, as shown inFIGS. 3 and 4, the pad is wider than thehousing12. In a further embodiment, the housing may be wide enough to completely receive the mountingpad80, as will be described in further detail below.
• Therelease button66 is normally biased upwardly by means of atension spring82 connected between a forwardly extendinghook84 of theretainer30 and a rearwardly extendinghook86 of therelease lever60. In this position, thecannula housing28 is locked to theretainer30 and is slidable therewith along thehousing12 between the extended and retracted positions. Since therelease lever60 is pivotally connected to theretainer30, it is also slidable with the retainer to maintain the cannula housing in a locked position until the housing is released by depressing therelease button66. When theretainer30 is retracted, therelease button66 is located within thehousing12 and therefore cannot be accessed until the retainer is extended to expose the release button. In this manner, thecannula housing28 cannot be inadvertently released during handling or positioning of theinserter assembly10, to thereby reduce the possibility of cannula contamination and/or injury. Depression of therelease button66 when theretainer30 is extended causes therelease lever60 to rotate (clockwise as viewed inFIG. 5) about the pivot joint64 against bias from thespring82 until thecatch68 clears the handle portion72 of thecannula housing28. In this position, the cannula housing and inserter assembly can be separated.
• As shown inFIG. 4, a pair of cockinglevers90 extend in opposite directions from opposite sides of theretainer30 and into thehousing slot78. The cocking levers90 can be grasped by a user to move theretainer30 and attachedcannula housing28 into the retracted position. A pair of tension springs92 (only one shown inFIGS. 4 and 6) are located on opposite sides of theretainer30. Eachtension spring92 has one end connected to ahook94 projecting downwardly from a rear end of theretainer side flange42 and an opposite end connected to ahook96 extending from theguide flange32 of theupper housing portion14. In this manner, theretainer30 is normally biased toward the extended position. In an alternative arrangement, a single, centrally mounted tension or compression spring may be used to bias theretainer30 toward the extended position. In a further embodiment, the one or both tension springs may be replaced with other biasing means, such as an elastomeric member, an air cylinder, and so on.
• A retainer release lever98 (FIG. 5) is pivotally connected to theupper housing portion14 by apivot pin100 that extends between theguide flanges32 and through thelever98. Arelease button102 is located at a forward end of therelease lever98 and projects upwardly through anopening104 in anupper wall105 of theupper housing portion14. Acatch106 is located at a rearward end of therelease lever98 and projects downwardly therefrom. Thecatch106 is arranged to fit within arecess108 of theretainer30 and hold the retainer in the retracted position under bias from thetension spring92. Acompression spring114 is positioned in abore110 formed in the rearward end of therelease lever98 and extends to acorresponding depression112 formed in theupper wall105 of theupper housing portion14 to normally bias thecatch106 toward therecess108.
• In order to retract theretainer30, including the attachedcannula housing12, to a cocked position, the levers90 (FIG. 4) are grasped by a user to slide theretainer30 rearwardly in thehousing12. A rear end of the retainer is initially in contact with a lower rampedsurface110 of thecatch106 and rearward movement of the retainer causes thecatch106 to rotate upwardly about the pivot pin100 (clockwise as viewed inFIG. 5) against bias force from thespring114 until thecatch106 is clear of the retainer. Further rearward movement of the retainer causes thecatch106 to snap into therecess108 with a clear audible sound to thereby indicate to a user that theretainer30 is properly cocked.
• Once in the retracted position, the inserter assembly can be placed on the skin of a patient with thelower surface20 of the base18 positioned against a user's or patient'souter skin22. Therelease button102 can be depressed to rotate thecatch106 out of therecess108, which causes theretainer30 to slide forwardly to the extended position under force from thesprings92 at a relatively rapid rate. Forward movement of the retainer in this manner causes theneedle27 andcannula26 to pierce the skin at the proper angle and enter into the subcutaneous layer at the proper distance. Thecannula housing28 can then be released from theinserter assembly10 by depressing therelease button66, as previously described. The mountingpad80 can then be secured to the skin and theneedle27 removed in a well-known manner, thus leaving thecannula26 in place.
• Asafety button120 is mounted in theupper housing portion14 between theguide flanges32 for limited forward and rearward sliding movement. Thesafety button120 includes anupper portion122 that extends through arear opening124 in thetop wall105 for grasping by a user. A pair of resilient arms126 (only one shown inFIG. 4) extend from alower portion130 of thebutton120. Ahead128 is formed at the free end of each arm and is positioned to engage one of twodetents132,134 formed in theguide flanges32 which define unlocked and locked positions, respectively, of thesafety button120. In the locked position, thelower portion130 of thesafety button120 is adjacent aledge136 of the catch106 (FIG. 5), to prevent upward movement of thecatch106 and thus inadvertent release of theretainer30 and the attachedcannula housing28. In the unlocked position, theledge136 is clear of thelower portion130 to move upwardly when therelease button102 is depressed or when theretainer30 is moved to the retracted position.
• With reference now toFIGS. 7 and 8, a low-profile inserter assembly140 according to a second embodiment of the invention is illustrated, wherein like parts in the previous embodiment are represented by like numerals. Theinserter assembly140 is similar in construction to theinserter assembly10, with the exception that anupper housing portion142 andlower housing portion144 are narrowed in width behind therelease button102 to form a narrowedhandle portion146 that is easier to hold and manipulate. This narrower width necessitates moving the tension springs92 (not shown inFIG. 7) inward, closer to the longitudinal centerline of the housing. These springs will now be located under theretainer30 rather than on each side as shown inFIGS. 4 and 5. However they are attached to theretainer side flange42 and guideflange32 of theupper housing portion142 in a similar manner.
• With reference now toFIGS. 9-11, a low-profile inserter assembly150 according to a third embodiment of the invention is illustrated, wherein like parts in the previous embodiments are represented by like numerals. In this embodiment, aslot152 is formed in thebottom wall25 of thelower housing portion16. Asingle cocking lever154 extends downwardly through theslot152 from theretainer30. As shown, the cockinglever154 includes ahead portion156 that is larger than the slot and aneck portion158 that extends through the slot. Theneck portion158 is preferably integrally formed with theretainer30. Afastener160 is countersunk in thehead portion156 and extends through the head andneck portions156,158 and into theretainer30 for securing the head portion to the retainer.
• Thebottom wall25 is formed in adepression162 of thelower housing portion16 and is defined by a pair of inner side walls164 (only one shown inFIG. 9) that extend downwardly from thebottom wall25. An L-shapedguide flange166 is formed at each longitudinal side of theretainer30 and contacts thebottom wall25 andinner side wall164 to guide sliding movement of the retainer in a substantially linear direction.
• Operation of theinserter assembly150 is similar to the operation of theinserter assembly10, with the exception that a user sets the retainer in a retracted position by pushing thehead portion156 of the cockinglever154 rearwardly until thecatch106 is located in therecess108 of the retainer to thereby hold the retainer in the retracted position under bias force from thesprings92. Thehead portion156 is preferably entirely located within thedepression162 of thelower housing portion16 to prevent interference between the head portion and other objects, such as the skin or clothing of a user, and thus possible injury or misplacement of the cannula assembly in the skin during release of theretainer30.
• With reference now toFIGS. 12-14, a low-profile inserter assembly170 according to a fourth embodiment of the invention is illustrated, wherein like parts in the previous embodiments are represented by like numerals. Theinserter assembly170 includes ahousing172 that is relatively wide in comparison to the previous embodiments. Thehousing172 has anupper housing portion174 connected to alower housing portion176 in a manner as previously described. Abifurcated base178 is preferably integrally formed with thelower housing portion176 and includes spacedfeet180,182. Each foot has alower surface184 that extends at anacute angle0 with respect to alower surface186 of thelower housing portion176 so that an insertion needle17 andcannula26 of a low-profile cannula housing28 placed in theinserter assembly170 can be inserted into theskin24 at the proper angle, as previously described. In one preferred embodiment, theangle 0 is approximately 30° to accommodate a cannula that will extend approximately 30° with respect to theouter skin surface22. However, the actual angle can vary depending on the shape of the cannula housing, as well as the length of the needle andcannula assembly26. The spaced-apart feet offer greater stability over the previous embodiment and permit a fold of skin to be inserted therebetween during insertion of the needle andcannula assembly26 into the subcutaneous layer.
• A generally vertically extendingchannel190 is formed in a forward end of thehousing172. Preferably, the channel is wide enough to receive thecannula housing28 and the mountingpad80. A generally horizontally extendingslot192 is formed between theupper housing portion174 andlower housing portion176 and intersects with thechannel190. Theslot192 is dimensioned to receive thecannula housing28, the mountingpad80, and therelease button66 so that the cannula housing and mounting pad can be releasably connected to the retainer and moved into and out of thehousing172 without obstruction.
• It will be understood that the terms relating to orientation and/or position, such as upper, lower, forward, rearward, downward, bottom, and side, including their respective derivatives, as may be used throughout the specification, refer to relative rather than absolute orientations and/or positions.
• While the invention has been taught with specific reference to the above-described embodiments, those skilled in the art will recognize that changes can be made in form and detail without departing from the spirit and the scope of the invention. For example, although the present invention has been described for use with a low profile or angled infusion set, it will be understood that the invention may be used to insert straight infusion sets or other types of needles and/or cannulas. Thus, the described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims (11)

1. An inserter for a low-profile angled infusion set, the low-profile inserter comprising:

an inserter housing having a bottom wall, and a distal end defining an opening therein;

a retainer slideably mounted in the inserter housing for movement between retracted and extended positions in a direction substantially parallel with the bottom wall, the retainer being adapted to releasably receive the infusion set, including a cannula and an insertion needle, the cannula and insertion needle defining an insertion axis;

a tension spring for biasing said retainer toward said extended position, said tension spring being movable between an expanded position when said retainer is in said retracted position, and a contracted position when said retainer is in said extended position;

a release lever releasably holding the retainer in the retracted position;

a first release button for releasing said tension spring from said expanded position, said first release button movable in a direction substantially normal to said insertion axis; and

a base member connected to the inserter housing, the base member having a lower surface that is adapted to contact a user's skin surface, the lower surface and the bottom wall forming an acute angle, wherein the cannula and the insertion needle are guided to be inserted subcutaneously along the insertion axis at said acute angle with respect to the skin surface.

2. An inserter according toclaim 1, and further comprising a safety member slideably mounted to the inserter housing to prevent inadvertent release of the retainer.

3. An inserter according toclaim 2, wherein the release lever includes a first end portion exposed through the housing for manipulation by an operator and a second end portion for engagement with the retainer to hold the retainer in the retraced position, whereby pivotal movement of the release lever in a first rotational direction causes disengagement of the second end portion and the retainer to release the retainer.

4. An inserter according toclaim 3, wherein the release lever is biased in a second rotational direction opposite the first rotational direction, such that movement of the retainer toward the retracted position causes the second end portion of the release lever to engage and hold the retainer.

5. An inserter according toclaim 4, wherein the safety member comprises a lower surface that, in a first locking position, engages the second end portion of the release lever to block movement of the release lever in the first rotational direction.

6. An inserter according toclaim 1, wherein the acute angle is in a range of about 10 degrees to about 40 degrees.

7. An inserter according toclaim 1, wherein the acute angle is approximately 30 degrees.

8. An inserter for an infusion set, the inserter comprising:

an inserter housing defining an opening in a distal end thereof;

a retainer slideably connected to the inserter housing for movement between retracted and extended positions, the retainer being adapted to releasably receive the infusion set including a cannula and an insertion needle, the cannula and the insertion needle defining an insertion axis;

a biasing member connected between the retainer and the inserter housing for biasing the retainer toward the extended position, said biasing member being expanded when said retainer is in said retracted position, and contracted when said retainer is in said extended position;

a first release button for releasing said biasing member from being expanded, movable in a direction substantially normal to said insertion axis; and

a base attached to a lower surface of said inserter housing defining an acute angle with respect to said inserter housing, for guiding the insertion needle and the cannula to be inserted subcutaneously in skin of a user, along the insertion axis and at the acute angle with respect to the skin.

9. An inserter according toclaim 8, further comprising a release lever mounted for pivotal movement on the retainer, the release lever including a first end portion exposed for manipulation by an operator when the retainer is in the extended position and a second end portion for engagement with the cannula assembly to hold the cannula assembly on the retainer, wherein pivotal movement of the release lever in a first rotational direction causes disengagement of the second end portion of the release lever and the cannula assembly to release the cannula assembly from the inserter.

10. An inserter according toclaim 9, wherein the release lever is biased in a second rotational direction opposite the first rotational direction, such that movement of the retainer toward the retracted position causes the second end portion of the release lever to engage and hold the retainer.

11. A method for inserting an insertion needle and a cannula into skin of a user, comprising the steps of:

providing an inserter housing having a bottom wall, a distal end defining an opening therein, and a base member attached to the bottom wall proximate the distal end, said base member including a lower surface adapted to contact the skin and defining an acute angle with said bottom wall;

slideably mounting a retainer within said inserter housing, movable between a retracted position and an extended position, said extended position being substantially parallel with said bottom wall of said inserter housing;

mounting the cannula and the insertion needle in said retainer to define an insertion axis;

providing a tension spring for biasing said retainer toward said extended position, movable between an expanded position and a contracted position;

releasing said tension spring by pressing a release button proximate said distal end of said inserter housing, in a direction substantially normal to the insertion axis, thereby releasing said spring to move from said expanded position to said contracted position and move said retainer to said extended position, whereby said insertion needle and said cannula are guided to be inserted subcutaneously in the skin at said acute angle with respect to the skin.

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