WO2015138302A1

WO2015138302A1 - Penile prosthesis cylinder having an expandable tip

Info

Publication number: WO2015138302A1
Application number: PCT/US2015/019413
Authority: WO
Inventors: Jonathan J. Lund; Brian P. Watschke; Eric F. LITTLE
Original assignee: Ams Research Corporation
Priority date: 2014-03-11
Filing date: 2015-03-09
Publication date: 2015-09-17

Abstract

An inflatable penile prosthesis cylinder (102) configured for implantation in a corpus cavernosum of a patient includes at least one stiffening member (114) and an expandable tip (132). The at least one stiffening member has an inflated state and a deflated state. The expandable tip is at a distal end (116) of the cylinder and is configured to expand at least one of radially and axially relative to a longitudinal axis (122) of the cylinder as the expandable tip is transitioned between a deflated state (137) to an inflated state (138).

Description

PENILE PROSTHESIS CYLINDER HAVING AN EXPANDABLE TIP

BACKGROUND

[0001] Erectile dysfunction (ED) is the inability to get or keep an erection that is firm enough, or lasts long enough, to have successful sexual intercourse. It can have serious effects on a person's sexual relationship and their self- esteem. Erectile dysfunction is caused by several factors that contribute to erection and ejaculation. Physical and mental stimulants, hormones, neural transmissions and feedback, muscle contractions and relaxations, and cardiovascular blood flow all work together to create and maintain an erection leading to ejaculation. When any of these processes are disrupted, it can cause erectile dysfunction. The causes of ED are generally divided into two major categories: those that are psychological in nature and those that are physical (or organic) in nature.

[0002] One technique for treating ED is a penile implant, or a penile prosthesis. The penile prosthesis is concealed entirely within the body and requires some degree of manipulation before and after intercourse to make the penis erect or flaccid. There are different types of implants based on the manner of operation, naturalness of the erection and the number of components implanted.

[0003] A three-piece inflatable penile prosthesis provides a more natural appearing erection than the two-piece or malleable implants. A three-piece penile prosthesis typically consists of a pair of cylinders implanted in the corpus cavernosa, a single pump bulb implanted in the scrotum, and a reservoir implanted in the abdomen. This three-piece prosthesis acts and feels more like a natural erection compared to one-piece implants or two-piece implants. Moreover, the three-piece feels softer and more flaccid when deflated compared to one-piece implants or two-piece implants. However, the three-piece prosthesis does have some challenges when in use such as the requirement of some manual dexterity, possibility of leakage, malfunction causing unintentional erections and implantation of a reservoir in the abdomen. [0004] A two-piece inflatable prosthesis typically consists of a pair of cylinders implanted in the corpus cavernosum and an inflation apparatus, such as a single pump bulb, implanted in the scrotum. A reservoir containing inflation fluid is contained at the rear of each cylinder. Patients simply squeeze the pump to drive fluid from the reservoir of each cylinder into the forward inflatable portion of the cylinder to inflate the cylinders. Fluid may be returned from the inflatable portion back to the reservoir by bending the penis. This closed, fluid- filled system allows for good rigidity and partial flaccidity. Moreover, the two- piece penile prosthesis does not require an abdominal incision. However, the two-piece prosthesis does have some challenges when in use, such as reduced flaccidity.

[0005] There is a continuous demand for improvements to inflatable penile prostheses, including improvements that lead to a more natural looking erect condition.

SUMMARY

[0006] Embodiments of the invention are directed to an inflatable penile prosthesis cylinder, a penile prosthesis that includes the cylinder, and methods of treating erectile dysfunction of a patient using the penile prosthesis or cylinder. In some embodiments, the inflatable penile prosthesis cylinder is configured for implantation in a corpus cavernosum of a patient and includes at least one stiffening member and an expandable tip. The at least one stiffening member has an inflated state and a deflated state. The expandable tip is located at a distal end of the cylinder and is configured to expand at least one of radially and axially relative to a longitudinal axis of the cylinder as the expandable tip is transitioned between a deflated state to an inflated state.

[0007] Some embodiments of the penile prosthesis comprise a pair of the inflatable penile prosthesis cylinders and an inflation device that is configured to drive fluid into the at least one stiffening member and the expandable tip. [0008] In some embodiments of a method of treating erectile dysfunction of a patient, an inflatable penile prosthesis cylinder is implanted in a corpus cavernosum of a penis of the patient. In some embodiments, the penile prosthesis cylinder includes at least one stiffening member, and an expandable tip at a distal end of the cylinder and located adjacent the glans penis. The penis is transitioned from a flaccid condition to an erect condition by driving fluid into the at least one stiffening member and the expandable tip, which expands radially and/or axially relative to a longitudinal axis of the cylinder.

[0009] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the Background.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a schematic perspective view of an exemplary penile prosthesis comprising inflatable penile prosthesis cylinders in accordance with one or more embodiments of the invention.

[0011] FIG. 2 is a simplified block diagram of the penile prosthesis in accordance with embodiments of the invention.

[0012] FIG. 3 is a simplified cross-sectional view of a penis with an inflatable penile prosthesis cylinder implanted in the corpus cavernosum.

[0013] FIG. 4 is a simplified cross-sectional view of a penile prosthesis cylinder in accordance with embodiments of the invention, taken generally along line 4-4 of FIG. 1.

[0014] FIGS. 5 and 6 are simplified cross-sectional views of a distal end of a penile prosthesis cylinder in accordance with embodiments of the invention.

[0015] FIG. 7 is a flowchart illustrating the method in accordance with embodiments of the invention. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0016] Embodiments of the invention are described more fully hereinafter with reference to the accompanying drawings. Elements that are identified using the same or similar reference characters refer to the same or similar elements. The various embodiments of the invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0017] Specific details are given in the following description to provide a thorough understanding of the embodiments. However, it is understood by those of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits, systems, networks, processes, frames, supports, connectors, motors, processors, and other components may not be shown, or shown in block diagram form in order to not obscure the embodiments in unnecessary detail.

[0018] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0019] It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, if an element is referred to as being "directly connected" or "directly coupled" to another element, there are no intervening elements present.

[0020] It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. Thus, a first element could be termed a second element without departing from the teachings of the present invention.

[0021] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0022] Embodiments of the invention may also be described using flowchart illustrations and block diagrams. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be rearranged. A process is terminated when its operations are completed, but could have additional steps not included in a figure or described herein.

[0023] It is understood that one or more of the blocks (of the flowcharts and block diagrams) may be implemented by computer program instructions. These program instructions may be provided to a processor circuit, such as a microprocessor, microcontroller or other processor, which executes the instructions to implement the functions specified in the block or blocks through a series of operational steps to be performed by the processor(s) and corresponding hardware components.

[0024] FIG. 1 is a schematic perspective view of an exemplary penile prosthesis 100 for treating erectile dysfunction that includes a pair of inflatable penile prosthesis cylinders 102, in accordance with one or more embodiments of the invention. FIG. 2 is a simplified block diagram of the penile prosthesis 100 in accordance with embodiments of the invention. While the exemplary penile prosthesis 100 is depicted as a two-piece inflatable penile prosthesis, the cylinders 102 may also be used with three-piece inflatable penile prostheses or other penile prostheses that utilize inflatable cylinders, as is readily apparent to those skilled in the relevant art.

[0025] In some embodiments, the cylinders 102 are each configured for implantation in one of the corpus cavernosum of the penis of a patient. In some embodiments, each cylinder 102 includes a fluid reservoir 104 located in a rear tip 105, an inflatable portion 106, and a fluid control block 108. In some embodiments, the fluid reservoir 104 is positioned at another location, such as externally to the cylinder 102. In some embodiments, the fluid control block 108 includes fluid pathways and valves that fluidically connect components of the inflatable portion 106 to tubing 110 and the reservoir 104, in accordance with conventional penile prosthesis cylinders, to control fluid flow between the reservoir 104 and components of the inflatable portion 106. The cylinders 102 may also comprise conventional components that are not shown in the drawings in order to simplify the illustrations.

[0026] FIG. 3 is a simplified cross-sectional view of a penis 109 with the cylinder 102 implanted in the corpus cavernosum 111. As shown in FIG. 3, the proximal end or rear tip 105 of the cylinder 102 is positioned adjacent the base of the penis, and the inflatable portion 106 extends toward a distal end of the cylinder 102, which is located the glans penis 113. In some embodiments, fluid in the reservoir 104 is driven through the tubing 110, the fluid control block 108, and into the inflatable portion 106 using an inflation device 112, such as a pump bulb or other suitable device. This transitions the penile prosthesis 100 or cylinder 102 from a deflated state or flaccid condition to a rigid state corresponding to an erect penis condition, which is shown in FIG. 3. Fluid contained in the inflatable portion 106 may be returned to the reservoir 104 of the cylinder 102 through the fluid control block 108 using conventional techniques, to transition the penile prosthesis 100 or cylinder 102 to the deflated state or flaccid condition. For example, a high pressure condition may be generated within the inflatable portion 106 by bending the cylinder 102, which opens a ball valve in the fluid control block 108 and allows fluid in components of the inflatable portion 106 to flow back to the reservoir 104.

[0027] In some embodiments, the inflatable portion 106 includes at least one stiffening member 114 (hereinafter "stiffening members"), which may be formed of silicone or other suitable material, as shown in FIG. 2. In some embodiments, the inflatable portion 106 includes a plurality of the stiffening members 114, as shown in FIG. 4, which is a simplified cross-sectional view of a penile prosthesis cylinder 102 in accordance with embodiments of the invention taken generally along line 4-4 of FIG. 1. In some embodiments, the stiffening members 114 extend along a longitudinal axis 122 of the cylinder 102 between rear tip 105 and a distal end 116, as shown in FIGS. 2 and 3.

[0028] In some embodiments, the stiffening members 114 are contained within an outer tube member 120 that is generally coaxial to a longitudinal axis 122 of the cylinder 102. The outer tube member 120 may be formed of silicone or other suitable biocompatible material.

[0029] In some embodiments, each stiffening member 114 is a balloon-like structure that includes an interior chamber 128 that is in fluid communication with the reservoir 104 through, for example, the fluid control block 108, or other suitable arrangement. Each stiffening member 114 may be transitioned from a deflated or contracted state, in which a low volume of fluid is contained in the chamber 128, to an inflated or expanded state, in which a higher volume of fluid is contained in the chamber 128, by driving fluid from the reservoir 104 into the stiffening member 114 using the inflation device 112.

[0030] In some embodiments, the stiffening members 114 expand in at least a radial direction relative to the axis 122, and press against each other and an interior wall 130 of outer tube member 120, shown in FIG. 4. The outer tube member 120 is configured to constrain the radial expansion of the stiffening members 114. The constrained expansion of the stiffening members 114 in their expanded states and the resultant tensile stress generated in the outer tube member 120, causes the inflatable portion 106 to become rigid and generate an erect penis condition when implanted in a corpus cavernosum 111 of a patient, as shown in FIG. 3.

[0031] In some embodiments, the inflatable portion 106 does not include the outer tube member 120. In some embodiments, the stiffening members 114 are joined together or a single stiffening member 114 is used. In some embodiments, the radial expansion of the stiffening members 114 relative to the longitudinal axis 122 during inflation of the stiffening members 114 is constrained by tensile stresses in the walls of the stiffening members 114. In some embodiments, the radial expansion of the stiffening members 114 relative to the longitudinal axis 122 during inflation of the stiffening members 114 is constrained by tensile stresses in the patient's tunica when the cylinder 102 is implanted in the corpus cavernosum. In some embodiments, tensile stresses within the walls of the inflated stiffening members 114 and/or the patient's tunica, cause the inflatable portion 106 to become rigid and generate an erect penis condition when implanted in a corpus cavernosum 111 of a patient.

[0032] Fluid is discharged from the chambers 128 and returned to the reservoir 104 to transition the stiffening members 114 to the deflated or contracted state. In some embodiments, this deflation of the stiffening members 114 radially contracts the stiffening members 114 and decreases the pressure on the interior wall 130 of the outer tube member 120. In some embodiments, the outer tube member 120 and the deflated stiffening members 114 are flexible, resulting in a softened inflatable portion 106 and a flaccid penis condition when the cylinder 102 is implanted in the corpus cavernosum of a patient.

[0033] In some embodiments, the inflatable portion includes a low friction barrier 131 between the interior wall 130 of the outer tube member 120 and the stiffening members 114, as shown in FIG. 4. The low friction barrier 131 reduces binding of the stiffening members 114 when they expand within the outer tube member 120. In some embodiments, the low friction barrier 131 includes a sleeve or layer of fabric.

[0034] In some embodiments, the inflatable portion 106 includes an expandable tip 132 at the distal end 116 of the penile prosthesis cylinder 102 opposite the rear tip 105, as shown in FIGS. 1 and 2. In some embodiments, the expandable tip 132 is formed of silicone or other suitable material, and is positioned adjacent or within the glans penis 113 of the patient when the cylinder 102 is implanted in the corpus cavernosum 111 of the patient, as shown in FIG. 3. In some embodiments, the expandable tip 132 is a balloon-like structure that includes an interior chamber 136 that is in fluid communication with the reservoir 104 through, for example, the fluid control block 108, or other suitable arrangement. The expandable tip 132 may be transitioned from a deflated or contracted state, in which a low volume of fluid is contained in the chamber 136, to an inflated or expanded state, in which a higher volume of fluid is contained in the chamber 136, by driving fluid from the reservoir 104 into the expandable tip 132 using the inflation device 112. In some embodiments, this inflation of the expandable tip 132 occurs concurrently with the inflation of the stiffening members 114.

[0035] In some embodiments, the expandable tip 132 expands radially and/or longitudinally relative to the axis 122 as the expandable tip 132 transitions from the deflated state 137, which is indicated by solid lines in FIG. 2, to the inflated state 138, which is indicated in phantom lines in FIG. 2. In some embodiments, the expandable tip 132 has a greater diameter 139 than the outer tube member 120, when the stiffening members 114 and the expandable tip 132 are in their inflated or expanded states, as indicated in FIG. 2. When the penile prosthesis cylinders 102 are installed in the corpus cavernosa 111 of a patient, the expansion of the expandable tip 132 expands the glans penis 113. This results in an erect condition of the penis that is more natural looking than that formed using conventional penile prostheses. [0036] In some embodiments, the expandable tip 132 extends from the distal end 116 of the cylinder 102 or the distal end of the outer tube member 120, such that at least a portion of the expandable tip 132 lies outside and distally to the outer tube member 120. In some embodiments, the expandable tip extends through an opening 140 in the outer tube member 120, as shown in FIG. 1. Thus, in some embodiments, at least a portion of the expandable tip 132 is unconstrained by the outer tube member 120, and expands relative to the section of the inflatable portion 106 corresponding to the stiffening members 114 and the outer tube member 120, as indicated in FIG. 2.

[0037] FIGS. 5 and 6 are simplified cross-sectional views of a distal end 116 of a penile prosthesis cylinder 102 in accordance with one or more embodiments of the invention. In some embodiments, each penile prosthesis cylinder 102 includes one or more stiffening members 114 within the outer tube member 120, a low friction barrier or fabric layer 131, and/or other elements described above. In some embodiments, a fluid pathway 141 fluidically connects reservoir 104 to the expandable tip 132, such as through the fluid control block 108, for example. In some embodiments, the fluid pathway 141 is formed between the stiffening members 114, as shown in FIGS. 4-6. In some embodiments, the fluid pathway 141 is formed through the stiffening members 114, such as through the chambers 128. In some embodiments, the fluid pathway 141 extends along the longitudinal axis 122 adjacent to the stiffening members 114, as shown in FIG. 4. In some embodiments, the fluid pathway 141 is substantially coaxial to the longitudinal axis 122. In some embodiments, the fluid pathway 141 is formed by tubing or conduit.

[0038] In some embodiments, the expandable tip 132 is attached to one or more of the stiffening members 114, as shown in FIG. 5. In some embodiments, the stiffening members 114 include a distal end portion 142 that is attached to or received within a proximal end 146 of the expandable tip 132. In some embodiments, the proximal end 146 of the expandable tip 132 is secured to the portion 142 using a suitable adhesive or other fastening technique. In some embodiments, the attachment of the proximal end 146 of the expandable tip 132 to the portion 142 forms a seal between the expandable tip and the one or more stiffening members 114. In some embodiments, the portions 142 form a port to the fluid flow pathway 141.

[0039] In some embodiments, the expandable tip 132 is attached to a distal end 148of the outer tube member 120 using a suitable adhesive, a weld, or other suitable technique, as shown in FIG. 6. In some embodiments, the expandable tip 132 forms the distal end 116 of the cylinder 102. In some embodiments, the expandable tip 132 is configured to expand or yield to internal pressure more readily than the outer tube member 120. In some embodiments, this is accomplished by forming the expandable tip 132 from a more elastic material than that used to form the outer tube member 120, and/or by making the wall of the expandable tip 132 thinner than the wall of the outer tube member 120. In some embodiments, the outer tube member 120 and the expandable tip 132 are formed as a unitary body, such as through a molding or other suitable process, with the wall of the outer tube member 120 being formed thicker than the wall of the expandable tip 132. As fluid is driven into the chamber 136, the expandable tip 132 expands radially and/or axially relative to the longitudinal axis 122, as indicated in FIG. 6.

[0040] In some embodiments, as fluid is driven into the chambers 128 of the one or more stiffening members 114, and into the chamber 136 of the expandable tip 132 through the fluid pathway 141, the section of the inflatable portion 106 corresponding to the one or more stiffening members 114, and the outer tube member 120 becomes rigid, and the expandable tip 132 expands to the expanded condition 138 shown in phantom lines in FIGS. 5 and 6. As discussed above, this places the penile prosthesis 100 in an inflated state corresponding to an erect condition. Fluid may then be discharged from the chambers 128 and 136 to transition the stiffening members 114 and the expandable tip 132 to their deflated or contracted states to place the penile prosthesis in a flaccid condition. [0041] Additional embodiments of the invention are directed to a method of using the penile prosthesis 100 formed in accordance with one or more embodiments described above to treat erectile dysfunction of a patient. FIG. 7 is a flowchart illustrating the method in accordance with embodiments of the invention. At 150, an inflatable penile prosthesis cylinder 102 is implanted in the corpus cavernosum 111 of the penis 109 of the patient, such as shown in FIG. 3. In some embodiments, the penile prosthesis cylinder 102 includes at least one stiffening member 114, and an expandable tip 132 at a distal end 116 of the cylinder 102. In some embodiments, the expandable tip 132 is located adjacent the glans penis 113 (FIG. 3). At 152, fluid is driven into the at least one stiffening member 114 to stiffen the inflatable chamber 106 of the cylinder 102. At 154, fluid is driven into the expandable tip 132 to expand the expandable tip 132 radially and/or axially relative to the longitudinal axis 122. Steps 152 and 154 operate to transition the penis from a flaccid condition to an erect condition (FIG. 3). In some embodiments of the method, the glans penis is expanded in response to the expansion of the expandable tip 132.

[0042] In some embodiments of steps 152 and 154, fluid is driven from a fluid reservoir 104 into the at least one stiffening member 114 and the expandable tip 132 using an inflation device 112. In some embodiments of step 154, fluid is driven alongside or through the at least one stiffening member 114 and into the expandable tip 132, such as through a fluid pathway 141 (FIGS. 4- 6).

[0043] In some embodiments of the method, the penis is transitioned from the erect condition to the flaccid condition by driving fluid out of the at least one stiffening member 114 and the expandable tip 132. This results in a reduction to the pressure applied to the interior wall 130 of the outer tube member 120 by the stiffening members 114 and a contraction of the expandable tip 132.

[0044] Although the present invention has been described with reference to preferred embodiments, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. An inflatable penile prosthesis cylinder (102) configured for implantation in a corpus cavernosum (111) of a patient comprising:

at least one stiffening member (114) having an inflated state and a

deflated state; and

an expandable tip (132) at a distal end (116) of the cylinder configured to expand at least one of radially and axially relative to a

longitudinal axis (122) of the cylinder as the expandable tip is transitioned from a deflated state to an inflated state.

2. The inflatable penile prosthesis cylinder according to claim 1, wherein the at least one stiffening member extends along the longitudinal axis

3. The inflatable penile prosthesis cylinder according to any of claims 1-2, wherein the at least one stiffening member includes a plurality of stiffening members.

4. The inflatable penile prosthesis cylinder according to any of claims 1-3, wherein the at least one stiffening member is configured to receive or discharge fluid to transition the at least one stiffening member between the inflated and deflated states.

5. The inflatable penile prosthesis cylinder according to any of claims 1-4, wherein the at least one stiffening member is contained in an outer tube member.

6. The inflatable penile prosthesis cylinder according to any of claims 1-5, including a fluid pathway extending through or alongside the at least one stiffening member to the expandable tip, wherein fluid is delivered to and from the expandable tip through the fluid pathway to transition the expandable tip between the inflated and deflated states.

7. The inflatable penile prosthesis cylinder according to any of claims 1-6, wherein the expandable tip is connected to a distal end of the at least one stiffening member.

8. The inflatable penile prosthesis cylinder according to any of claims 1-7, further comprising:

a fluid reservoir; and

a fluid control block configured to control fluid flow between the

reservoir and the at least one stiffening member, and to control fluid flow between the reservoir and the expandable tip.

9. A penile prosthesis comprising:

a pair of the inflatable penile prosthesis cylinders according to any of claims 1-8; and

an inflation device configured to drive fluid into the at least one

stiffening member and the expandable tip.

10. A method of treating erectile dysfunction of a patient comprising:

implanting (150) an inflatable penile prosthesis cylinder (102) in a corpus cavernosum (111) of a penis (109) of the patient, the penile prosthesis cylinder comprising:

at least one stiffening member (114); and

an expandable tip (132) at a distal end (116) of the cylinder and located adjacent the glans penis (113); and

transitioning the penis from a flaccid condition to an erect condition comprising:

driving (152) fluid into the at least one stiffening member to transition the at least one stiffening member from a deflated state to an inflated state; and

expanding the expandable tip radially and/or axially relative to a longitudinal axis (122) of the inflatable penile prosthesis cylinder comprising driving (154) fluid into the expandable tip.

11. The method of claim 10, further comprising expanding the glans penis in response to expanding the expandable tip.

12. The method according to any of claims 10-11, wherein driving fluid into the at least one stiffening member and driving fluid into the expandable tip comprise driving fluid from a fluid reservoir.

13. The method according to claim 12, wherein driving fluid from a fluid reservoir comprises driving fluid from the fluid reservoir using an inflation device.

14. The method according to any of claims 10-13, wherein driving fluid into the expandable tip comprises driving fluid through a fluid pathway that is alongside or through the at least one stiffening member and into the expandable tip.

15. The method according to any of claims 10-14, further comprising transitioning the penis from the erect condition to the flaccid condition comprising:

driving fluid out of the at least one stiffening member; and

contracting the expandable tip comprising driving fluid out of the

expandable tip.