Patent Description:
The present disclosure is directed to a collapsible and expandable liquid supply reservoir. More particularly, a portable reservoir is disclosed for medical applications such as trans-anal irrigation (TAI) or antegrade irrigation such as colostomy/stoma irrigation.

Many individuals suffering spinal cord injury and other medical conditions may need to avail themselves of bowel management treatments. Trans-anal irrigation (TAl) provides one option for bowel management. TAI is the delivery of irrigating liquid (usually water) into the colon to flush the system of stool and create pseudo-continence for the user. Systems currently on the market allow the user to utilize a product over the toilet, on a commode/shower chair or in a bed to introduce water into the bowel through a rectal catheter. The user will introduce an amount of water into the bowel (typically <NUM>-<NUM>) in order to flush out stool located in the bowel passage. The user will typically introduce the water, wait for a period of time and allow gravity to flush the water and stool out of the body. The rectal catheter may have an inflatable/deflatable balloon to assist in retention of the catheter during water introduction. A particularly suitable TAI device is shown in <CIT>, and <CIT>, and which are shown in <CIT>.

The typical TAI device has an irrigation liquid reservoir and a pump base unit which contains a pump for pumping water from the reservoir through suitable tubing to the catheter. Optionally the reservoir may be made separable from the pump base unit and tubing. This makes filling the reservoir easier since just the reservoir can be carried to a faucet to fill it, without the need to move the pump base unit or tubing along with the reservoir. Alternately, the reservoir may be integrated with the pump base unit.

It is desirable that when the reservoir is not in use, it can be collapsed to minimize the volume of the device for storage. When in use the reservoir expands and creates an enclosure that contains water used for irrigation and retention balloon inflation. Among the challenges faced in designing a reservoir for use with a TAI device is the reservoir must withstand long-term use wherein it will be frequently expanded and collapsed. Furthermore, users often have limited dexterity so the reservoir must perform correctly without requiring fine motor skills on the part of the user.

Problems encountered in some designs of a collapsible reservoir include: failing to collapse completely; requiring too large of a force to collapse the reservoir; failing to remain in the collapsed or expanded position as desired; substantial buckling of the reservoir walls as it is collapsed; and sagging or drooping of the walls when in the expanded position. Buckling is a torsional motion within the thicker wall segments, which leads to incomplete or unpredictable collapse and the result that the flexible wall segments do not nest together properly. The present disclosure is directed to a new reservoir design that will address these items by: causing the reservoir to expand and collapse fully and then remain in the collapsed and expanded positions as desired, i.e., there is no snapping back up or down; reducing the force required to collapse the reservoir; and eliminating any buckling or instability as the reservoir expands or collapses. <CIT> discloses irrigation bags of a foldable or collapsible structure which can be readily folded and placed in a compact space for moving, storing, or when traveling. The bags have substantially similar collapsible sections which collapse on top on each other. <CIT> discloses molded plastic containers for use including storage of food items, which can be sealed. The food containers are collapsible or foldable to a compact position when empty for storage purposes. <CIT> discloses collapsible fountain syringes of the bellows type that will occupy a small depth when collapsed.

The invention is defined by the features of independent claim <NUM>. In one aspect, the present disclosure concerns a water supply for a TAI or colostomy/stoma irrigation device having a reservoir mounted on a pump base unit. The reservoir is collapsible for storage and expandable for use. It has a flexible wall having a corrugated or bellows-like construction formed by three steps which are nested together. There is a lower step, a middle step and an upper step. Each step comprises a riser and a tread which are pivotably connected to one another at an external hinge. The lower and middle steps in turn are pivotably connected to one another at a first internal hinge. Similarly, the middle and upper steps are pivotably connected to one another at a second internal hinge. Finally, the upper step is pivotably connected to a collar connector at a third internal hinge.

To improve manufacturability and to minimize production costs, the reservoir of the present disclosure will be manufactured in the collapsed position. A suitable manufacturing method is compression molding, although other methods are possible. The overall shape of the reservoir can be described as a truncated pyramid. That is, the reservoir has a generally square base but with rounded corners. Its flexible wall is joined to the perimeter of the square base and comprises four trapezoidal side panels which incorporate the three steps. The trapezoidal side panels are joined to one another at rounded corners. The side panels converge toward the top where they are attached to a generally square collar at the top of the panels. The pyramidal shape of the side walls permits the reservoir to mate with a square pump base unit. Having a square pump base unit is advantageous in terms of fitting the pump, batteries, solenoid valves, tubing and circuit board in the pump base unit.

The present disclosure is directed to a trans-anal irrigation (TAI) device which is shown generally at <NUM> in <FIG> where it is shown deployed for use. The main components of the device <NUM> include a pump base unit <NUM>, an irrigation fluid reservoir <NUM>, fluid tubing <NUM>, a connector hub <NUM>, a disposable rectal catheter <NUM>, and a wireless controller <NUM>, with an optional lanyard <NUM> attached to the controller.

The reservoir <NUM> has a flexible side wall <NUM> that extends from an upstanding outer wall <NUM> at the bottom to a collar <NUM> at the top. Both the outer wall <NUM> and the collar <NUM> are relatively rigid. Although it is not shown here, it will be understood that the outer wall <NUM> is attached to a generally horizontal, relatively rigid bottom wall or base. The bottom wall or base has a generally square shape with rounded corners. The upstanding outer wall <NUM> is attached to and extends around the perimeter of the horizontal bottom wall. Preferably the bottom wall and outer wall <NUM> are molded as a single unit. The lower end of the flexible side wall <NUM> overlaps and is fixed to the interior surface of the outer wall <NUM> in sealing engagement. The upper end of the flexible side wall is fixed to the collar <NUM>.

The collar <NUM> has a handle <NUM> pivotably connected to it. A user can pivot the handle up <NUM>° from the position illustrated in <FIG> to carry the reservoir <NUM>. The collar <NUM> defines an opening <NUM> at the top of the reservoir. This opening may receive a funnel (not shown) therein. The funnel may have a fill tube connected to it. The funnel can be removed from the collar <NUM> and placed underneath a faucet for filling the reservoir. The free end of the fill tube would be placed through the collar <NUM> and into the reservoir cavity for this purpose. Water from the faucet flows through the funnel and fill tube and into the reservoir <NUM>.

It will be understood if the reservoir is removable from the pump base unit then the reservoir bottom wall will have a valve in it that provides selectable fluid communication between the interior of the reservoir and a conduit joined to one of the pump flow control valves. The valve automatically closes when the reservoir <NUM> is removed from the pump base unit <NUM> and automatically opens when the reservoir is mounted on the pump base unit <NUM>. The pump base unit may also mount a temperature sensor (not shown) that electronically communicates with the controller <NUM>.

The flexible side wall <NUM> is formed by three step sections of progressively smaller outer dimension from bottom to top. Successive riser segments of the flexible side wall are joined by an intervening tread segment. The junctions between the riser and tread segments form flexible hinges that provide an overall stair-stepped construction to the expanded reservoir. Thus, the side wall <NUM> functions somewhat in the nature of a bellows and permits the reservoir to be telescopically expanded (as shown in <FIG>) during use and collapsed (as shown in <FIG>) during storage.

<FIG> illustrates a few details of the pump base unit <NUM>. It has a generally hollow shell <NUM> which includes a perimeter wall <NUM>. The wall <NUM> surrounds the lower portion of the outer wall <NUM> of the reservoir <NUM> when the reservoir is installed on the pump base unit <NUM>. The wall <NUM> has a handle <NUM> pivotably connected to it. A user can pivot the handle up <NUM>° from the position illustrated in <FIG> to carry the pump base unit <NUM>. During use of the device a hollow cover <NUM> is removed from the top of the shell <NUM> and turned over to fit underneath the floor of the shell as seen in <FIG>. During storage the cover <NUM> fits over the reservoir and removably joins the wall <NUM> to form a compact structure for storage or transport.

Further details of the flexible side wall <NUM> of the reservoir <NUM> will now be described in connection with <FIG>. The flexible side wall has a corrugated or bellows-like construction formed by three steps which are nested together. There is a lower step <NUM>, a middle step <NUM> and an upper step <NUM>. Each step comprises a riser segment and a tread segment which are pivotably connected to one another at an external hinge. The risers for the three steps are designated 34A, 36A and 38A, respectively. The treads are designated 34B, 36B and 38B, respectively. The external hinges are designated 34C, 36C and 38C, respectively. The steps are also pivotably connected to each other. Thus, the lower and middle steps <NUM>, <NUM> are pivotably connected to one another at a first internal hinge <NUM>. Similarly, the middle and upper steps <NUM>, <NUM> are pivotably connected to one another at a second internal hinge <NUM>. Finally, the upper step <NUM> is pivotably connected at a third internal hinge <NUM> to a collar connector <NUM>.

The collar connector <NUM> has a generally vertical riser segment <NUM> that is somewhat truncated compared to the riser segments of the steps. The riser segment <NUM> is integrally attached to a horizontally disposed flange <NUM>. The flange <NUM> is fixed to the rigid collar <NUM> which forms the top of the reservoir. The upward arrows <NUM> in <FIG> indicate where an expanding force on the flange <NUM> would be applied. Similarly, the downward arrows <NUM> in <FIG> indicate where a collapsing force would be applied to the flange <NUM>.

Some of the design parameters of the flexible wall are shown in <FIG> and <FIG> and include the following:.

It has been found that the dimensions and geometry of the step segments and hinges are important to making the reservoir perform as desired. In particular, the collapsed, acute step angle must be greater than <NUM>° and more preferably greater than <NUM>°. The hinge thickness must be less than <NUM> and more preferably about <NUM>. The expanded, obtuse step angle must be greater than <NUM>° but no more than <NUM>° and more preferably <NUM>°. Similarly, the number of steps in combination with the foregoing preferences was found to be important as well. Limiting the number of steps to three and limiting the obtuse step angle when expanded to about <NUM>° allows all hinges to fold properly.

The reservoir is manufactured using silicone rubber (durometer <NUM> Shore A). The material durometer does not impact the dynamics of the reservoir as it is expanded and collapsed, but it will change the force required by the user to collapse or expand it. The material could have different characteristics and can be easily changed once a tool has been built. The material properties may be as shown in the following table:.

In this table the durometer (<NUM> Shore A) is converted to Young's Modulus using the formula: exp((Shore-A Durometer)*<NUM>-<NUM>). The tensile strength and yield strength value were obtained from Silicone Material Selection Guide.

With the design as shown all collapsing and expansion motion is isolated to the thin hinge sections while the thicker segments remain essentially rigid. It is preferred that the flexible portion of the reservoir be molded in the collapsed position as it is easier to manufacture this way. A draft angle of greater than <NUM>° is preferred, such as the <NUM>° draft angle shown in <FIG>.

Further, it will be noted that other than riser 34A, the flexible wall <NUM> of <FIG> shows the adjacent pairs of step segments are mirror images of each other. For example, tread 34B is a mirror image of its immediate neighbor, riser 36A and riser 36A is a mirror image of tread 36B, and so on. Riser 34A is not a mirror image of its tread 34B because riser 34A is longer than tread <NUM> and does not have a hinge formed at its base. Thus, the step segments are symmetric about bisectors through internal hinges <NUM> and <NUM> and external hinges 36C and 38C.

It is also pointed out that the cross-sections of symmetric step segments 34B, 36A, 36B, 38A and 38B are parallelograms. As seen in <FIG>, each segment has an elongated external face (one of which is designated <NUM>) and an elongated internal face (one of which is designated <NUM>). Elongated faces <NUM> and <NUM> are parallel to one another. Then at each end there is an angled run extending from the elongated face to the arcuate portions of the hinge. Thus, the external face <NUM> joins an angled run <NUM> and the internal face <NUM> joins an angled run <NUM>. The angled runs <NUM>, <NUM> are parallel to one another. This segment shape assures that the folding of the steps occurs at the hinges and that the elongated body portions of the step will not buckle.

Claim 1:
A collapsible irrigation device liquid reservoir (<NUM>) for colostomy/stoma irrigation, comprising a flexible side wall (<NUM>) having a lower step (<NUM>), a middle step (<NUM>) and an upper step (<NUM>), wherein the steps are of progressively smaller outer dimension from bottom to top, each of the steps comprising a riser segment (34A, 36A, 38A) and a tread segment (34B, 36B, 38B) pivotably connected to one another at an external hinge (34C, 36C, 38C), the step when collapsed defining an acute step angle between the riser and tread segments of about <NUM>°, and the step when expanded defining an obtuse step angle between the riser and tread segments of about <NUM>°, the tread of the lower step being pivotably connected to the riser of the middle step at a first internal hinge (<NUM>), and the tread of the middle step being pivotably connected to the riser of the upper step at a second internal hinge (<NUM>) .