Abstract
An implantable biocompatible expander suitable for implantation into a urinary duct, comprises an elongated sinusoidal ring comprising at least two proximal prongs and at least two distal prongs, wherein the expander is resiliently deformable from a relaxed radially expanded orientation to a radially contracted orientation suitable for transluminal delivery through the urinary duct. The expander is configured to exert an outward radial force against a wall of the urinary duct when in-situ within the urinary duct. In particular, the expander is suitable for treatment of benign prostatic hyperplasia and configured for implantation into the prostatic urethra between, and substantially spanning the prostatic urethra between, the bladder neck and external sphincter.
Claims
1. An implantable biocompatible expander suitable for treatment of benign prostatic hyperplasia (BPH), the expander comprising a single elongated undulating ring having three proximal prongs and three distal prongs, or five proximal prongs and five distal prongs, wherein the expander is resiliently deformable from a relaxed radially expanded orientation to a radially contracted orientation suitable for transluminal delivery through the urethra, wherein the expander is configured to span a substantial section of the prostatic urethra between the bladder neck and external sphincter and cause in-situ expansion of the substantial section of the prostatic urethra.
Description
BRIEF DESCRIPTION OF THE FIGURES
[0105] The invention will be more clearly understood from the following description of some embodiments thereof given by way of example only with reference to the accompanying figures in which:
[0106] FIG. 1 is an elevational view of a three-prong expander of the invention in a relaxed, expanded, state;
[0107] FIG. 2 is an elevational view of a three-prong expander of FIG. 1 in a contracted state;
[0108] FIG. 3 is a partly sectional view of the expander of FIG. 1 disposed within the prostatic urethra of a patient with benign prostatic hyperplasia in which the expander is exerting an outward radial pressure on the walls of the prostatic urethra causing dilation;
[0109] FIG. 4 is a partly sectional view similar to FIG. 2 showing the seminal vesicle and an ejaculatory duct entering the prostatic urethra;
[0110] FIG. 5 is a photograph of an expander of the invention in-situ within a prostatic urethra showing the three proximal prongs and three distal prongs;
[0111] FIG. 6 is an elevational view of a five-prong expander according to the invention;
[0112] FIG. 7 is an elevational view of a three prong expander according to the invention comprising a tapered sinusoidal ring;
[0113] FIG. 8 is an elevational view of a three prong expander according to the invention comprising a barrel-shaped sinusoidal ring;
[0114] FIG. 9 is an elevational view of a three prong expander according to the invention comprising in which the apices of the prongs are flared outwardly;
[0115] FIG. 10 is an elevational view of a three prong expander according to the invention in which the apices of the distal prongs are flared outwardly;
[0116] FIG. 11 is an elevational view of a three prong expander according to the invention in which the apices of the distal prongs comprise an inwardly flared loop and the apices of the proximal prongs comprise an outwardly flared loop;
[0117] FIG. 12 is an elevational view of a three prong expander according to the invention similar to the expander of FIG. 12 and in which the distal prongs are offset in height and the proximal prongs are offset in height to allow the distal and proximal loops dovetail when the expander is in a contracted orientation;
[0118] FIG. 13 is an elevational view of the three-prong expander of FIG. 12 shown in a contracted orientation;
[0119] FIG. 14 is an elevational view of a three-prong expander of the invention having looped apices on the distal and proximal prongs;
[0120] FIG. 15 is an elevational view of a three prong expander of the invention in which the struts of the distal prongs have a greater thickness that the struts of the proximal prongs;
[0121] FIG. 16 is an elevational view of a three prong expander of the invention in which the apices of the distal prongs are formed into an M-formation, and in which an end of the wire extends beyond one of the apices to provide a fixation barb;
[0122] FIG. 17 is an elevational view of a three-prong expander of the invention in which an end of the wire extends beyond one of the apices to provide a coil having a barbed end;
[0123] FIG. 18 is an elevational view of a three-prong expander of the invention in which each end of the wire extends longitudinally beyond the ends of the expander to provide distal and proximal barbs;
[0124] FIG. 19 is an elevational view of the three-prong expander of FIG. 1 having an anchoring element disposed on one of the longitudinal struts;
[0125] FIG. 20 is an elevational view of a three-prong expander of the invention in which each end of the wire extends longitudinally beyond the ends of the expander to provide distal and proximal barbs that extend circumferentially partially around each end of the expander;
[0126] FIG. 21 is an elevational view of a three-prong expander of the invention in which four of the struts are substantially linear and four of the struts are non-linear;
[0127] FIG. 22 is an elevational view of a two-prong expander of the invention shown in a relaxed expanded state;
[0128] FIG. 23 is an elevational view of the two-prong expander of FIG. 22 in which two of the longitudinal prongs comprise anchoring elements;
[0129] FIG. 24 is an elevational view of an alternative embodiment of two-prong expander of the invention shown in a relaxed expanded state;
[0130] FIG. 25 is an elevational view of an anchoring element shown disposed on a strut of an expander of the invention;
[0131] FIG. 26 is an elevational view of a further embodiment of anchoring element shown disposed on a strut of an expander of the invention;
[0132] FIG. 27 is an elevational view of a further embodiment of anchoring element shown disposed on a strut of an expander of the invention;
[0133] FIG. 28 is an elevational view of a further embodiment of anchoring element shown disposed on a strut of an expander of the invention;
[0134] FIG. 29 is an elevational view of a delivery device for an expander of the invention prior to insertion of the expander;
[0135] FIG. 30 is an elevational view of the delivery device of FIG. 20 showing the expander in-situ within the distal end of the device in a contracted orientation;
[0136] FIG. 31 is an elevational view of the delivery device of FIG. 20 showing the expander in-situ within the prostatic urethra after ejection from the distal end of the device; and
[0137] FIG. 32 is an elevational view of a distal end of an ejection element forming part of the delivery device of FIG. 29.
[0138] FIGS. 33 (A to D) illustrate a delivery device of the invention incorporating a cystoscope disposed concentrically with a lumen of the delivery device in use delivering an expander of the invention in the prostatic urethra.
[0139] FIG. 34 is a 3-D X-ray image showing an expander of the invention in-situ in the prostatic urethra of a canine.
[0140] FIGS. 35 and 36 are photographs showing an expander of the invention deployed in the prostatic urethra of a canine. The verumontanum is the ridge at six o'clock in the photos.
[0141] FIG. 37 illustrates a method of treating benign prostatic hyperplasia (BPH).
[0142] FIG. 38 illustrates an expander of the invention deployed in the prostatic urethra of a patent with BPH, between the bladder neck muscle and the external sphincter. This figure shows how the device accommodates the verumontanum between two prongs of the expander in the distal prostatic urethra, which the proximal end of the device is configured such that one of the prongs pushes the transition zone of the prostate gland away from the lumen of the prostatic urethra.
DETAILED DESCRIPTION OF THE INVENTION
[0143] The invention will now be described with reference to specific Examples. These are merely exemplary and for illustrative purposes only: they are not intended to be limiting in any way to the scope of the monopoly claimed or to the invention described. These examples constitute the best mode currently contemplated for practicing the invention.
Referring to the drawings, and initially to FIG. 1, there is illustrated an expander according to the invention indicated generally by the reference numeral 1. The expander 1 comprises a single nitinol wire configured as an elongated sinusoidal ring having a distal end 3 comprising three distal prongs 4 with apices 5 and a proximal end 6 having three proximal prongs 7 with apices 8. The prongs are connected by longitudinal struts 9. The expander 1 is shown in an expanded, relaxed, state and has a length of approximately 22 mm and a width of approximately 15 mm. In the expanded state shown, the distance between the apices 5 of adjacent distal prongs 4 at the distal end 3 of the expander is approximately 14 mm. Likewise, the distance between the apices 8 of adjacent proximal prongs 7 at the proximal end 6 of the expander is approximately 14 mm. The nitinol wire has a cross-sectional diameter of approximately 0.4 mm.
[0144] Referring to FIG. 2, the expander 1 is shown in a radially contracted state in which the distal and proximal prongs are brought together. In this contracted state, the cross-sectional area of the expander is reduced by more than 70% compared with the relaxed expanded state shown in FIG. 1, and the distance between adjacent distal and proximal prongs has reduced from 14 mm to 4-5 mm. In this contracted configuration, the resilient deformability of the sinusoidal ring configuration causes the ring to exert an outward radial force.
[0145] Referring to FIGS. 3 and 4 there is illustrated an expander of FIG. 1 shown in use in the treatment of benign prostatic hyperplasia. The expander 1 is disposed within the prostatic urethra 10 within the prostate gland 11 in between the bladder neck 12 and the external sphincter 13. In this position, the expander 1 exerts an outward radial force against the walls of the prostatic urethra 10 expanding the urethra to allow flow of urine. Due to the sinusoidal ring design, the outward radial force is greatest at each end of the expander, adjacent the transition zones of the prostatic urethra, where the greatest amount of diseased tissue is located. In addition, due to the design of the expander, the contact area between the struts and prongs of the expander and the wall of the prostatic urethra is minimised so that the seminal ducts 15 are not obstructed by the walls of the expander. In addition, as the expander does not have any circumferential struts, removal of the expander is facilitated.
[0146] FIG. 5 is a picture of the expander of the invention inserted into the prostatic urethra of a cadaver, showing the proximal end of the expander in the foreground and the distal end of the expander in the background abutting the bladder neck. The picture illustrates how the struts of the expander are invaginated into the wall of the prostatic urethra.
[0147] Referring to FIG. 6, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 20 has five distal prongs 4 and five proximal prongs 7, and the use of this embodiment is the same as that described with reference to the previous embodiment.
[0148] Referring to FIG. 7, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 30 has three distal prongs 4 and three proximal prongs 7, and is longitudinally inwardly tapered towards the distal end 3 with the struts having an angle of between 5° and 15° with the longitudinal axis of the expander when in a relaxed state. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0149] Referring to FIG. 8, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 40 has three distal prongs 4 and three proximal prongs 7, and the struts are curved outwardly along their length so that the expander has a substantially barrel shape along its length. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0150] Referring to FIG. 9, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 50 has three distal prongs 4 and three proximal prongs 7, and the struts are curved inwardly along their length so that the expander has a substantially waisted shape along its length, with a narrowed central portion 51 and slightly widened ends 3, 6. In addition, the apices 5, 8 at each end are flared outwardly. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0151] Referring to FIG. 10, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 60 has five distal prongs 4 and five proximal prongs 7, and the apices 5 at the distal end 3 are flared outwardly. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0152] Referring to FIG. 11, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 70 has three distal prongs 4 and three proximal prongs 7. The apices 5 at the distal end 3 are formed into loops 71 that project radially inwardly, and the apices 8 at the proximal end 6 are formed into loops 72 that project radially outwardly. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0153] Referring to FIGS. 12 and 13, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 80 has three distal prongs 4 and three proximal prongs 7. The apices 5 at the distal end 3 are formed into loops 81 that project radially inwardly, and the apices 8 at the proximal end 6 are formed into loops 82 that project radially outwardly. In addition, the longitudinal position of the distal and proximal prongs is offset enabling the loops 81 to dovetail when the expander is in a contracted orientation (shown in FIG. 13). The use of this embodiment is the same as that described with reference to the previous embodiment.
[0154] Referring to FIG. 14, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 90 has three distal prongs 4 and three proximal prongs 7. The apices 5 at the distal end 3 are formed into loops 91 that project along a longitudinal axis of the expander, and the apices 8 at the proximal end 6 are formed into loops 92 that project along a longitudinal axis of the expander. In addition, the struts are curved outwardly. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0155] Referring to FIG. 15, there is illustrated an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 100 is formed of a nitinol wire that has a varying thick ness along its length, with the portions of the wire forming the distal prongs 4 being thicker that the portion of the wire that forms the proximal prongs 7. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0156] Referring to FIG. 16, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 110 has three distal prongs 4 and three proximal prongs 7. The apices 5 at the distal end 3 comprise M-shaped loops 111 that project along a longitudinal axis of the expander. In addition, the nitinol wire has an end 112 that extends beyond the distal end 3 of the expander and comprises a terminal barb 113 for fixing the expander in place (anchoring element). The use of this embodiment is the same as that described with reference to the previous embodiment.
[0157] Referring to FIG. 17, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. This embodiment is similar to that of FIG. 16 with the exception that the end of the nitinol wire forms two helical loops 114 and terminates in a barb 113 for fixing the expander in place (anchoring element). The use of this embodiment is the same as that described with reference to the previous embodiment.
[0158] Referring to FIG. 18, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 120 has three distal prongs 4 and three proximal prongs 7 and is formed from a nitinol wire that overlaps at a joining point 121 and has ends 122 and 123 that extend longitudinally beyond the ends of the expander and comprise terminal barbs 124 for fixing the expander in place (anchoring element). The use of this embodiment is the same as that described with reference to the previous embodiment.
[0159] Referring to FIG. 19, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander comprises an anchoring element 126 disposed on a longitudinal strut 9, the anchoring element comprising a strut-embracing sleeve 127 and upwardly projecting barbs 128.
[0160] Referring to FIG. 20, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. This embodiment is similar to that of FIG. 18 with the exception that the ends 122 and 123 extend substantially circumferentially around each end of the expander and comprise terminal barbs 124 for fixing the expander in place. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0161] Referring to FIG. 21, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 130 has three distal prongs 4 and three proximal prongs 7, and is longitudinally inwardly tapered towards the distal end 3 with the struts having an angle of between 5 and 15 degrees with the longitudinal axis of the expander when in a relaxed state. In addition, two adjacent struts 131 are cranked inwardly intermediate their ends providing a different angular spacing between the struts. The use of this embodiment is the same as that described with reference to the previous embodiment.
[0162] Referring to FIG. 22, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 150 is substantially the same as the expander illustrated in FIG. 1 with the exception that the expander comprises two distal and proximal prongs 4, 7 instead of three. The operation of this embodiment is the same as the embodiment of FIG. 1.
[0163] Referring to FIG. 23, there is illustrated the expander of FIG. 22 having anchoring elements 126 disposed on longitudinal struts 9. Each anchoring element 126 comprises a sleeve 127 that embraces a strut 9 and a pair of barbs 128 that project away from the strut at right angles to each other.
[0164] Referring to FIG. 24, there is illustrated an elevational view of an expander according to an alternative embodiment of the invention in which parts described with reference to the previous embodiments are assigned the same reference numerals. In this embodiment, the expander 150 is substantially the same as the expander illustrated in FIG. 22 with the exception that the apices of the distal prongs 4 are rounded.
[0165] Referring to FIGS. 25 to 28, there is illustrated a number of embodiments of anchoring elements 126, each comprising a sleeve 127 configured to embrace a strut 9 of an expander of the invention, and having barbs 128 that project away from the strut and when in-situ engage a wall of a body lumen. In the embodiment of FIG. 25, the barbs 128 are mounted at each end of a top of the sleeve 127 and project upwardly away from the strut at an angle of roughly 45 to the strut. In the embodiment of FIG. 26, one of the barbs 128 projects from a top of one end of the sleeve 127 and the other barb 128 projects from a bottom of an opposite end of the expander. In the embodiment of FIG. 27, the barbs 128 are cut-out from the top of the sleeve 127. In the embodiment of FIG. 28, a wire 129 is mounted to an inside of the sleeve 127 with each end of the wire 129 projecting proud of the sleeve forming the barbs 128.
[0166] Referring to FIGS. 29 to 31, there is illustrated a delivery device for delivering an expander of the invention to a target site within a body lumen, in this case delivery to the prostatic urethra. The device 200 comprises a handle 201, a delivery tube 202 having a having a hollow distal end 203 remote from the handle 201 configured to receive an expander of the invention in a contracted orientation, and an ejection element 205 operatively connected to the handle 201 and operable to eject a stent from the open end of the delivery tube. In more detail, the ejection means 205 comprises a shunt mechanism having a distal end 206 operatively connected to actuation means 207 on the handle and a proximal end disposed adjacent the distal end 203 of the tube 202. In use, the shunt mechanism is retracted and the expander 1 is compressed manually into a contracted shape and inserted into the hollow distal end of the delivery tube (FIG. 30). The delivery tube is then inserted into the urethra through the penis and advanced along the urethra until the distal end of the delivery tube is located within the prostatic urethra 10. The actuation means 207 on the handle is then actuated to extend the shunt mechanism and eject the expander 1 from the delivery tube into the prostatic urethra, where it expands to exert a radially outward pressure against the wall of the prostatic urethra (FIG. 31). The delivery tube is then retracted from the urethra.
[0167] Referring to FIG. 32, there is provided a detailed elevational view of part of the delivery device 200 of FIG. 29. In this embodiment, the ejection element 205 includes a distal head 210 having a triangular cross-section and configured to fit within a lumen of the expander when it is mounted within the delivery tube 202. Each of the three faces of the head 210 include a projection 211 together forming a jig for positioning and engaging the expander within the delivery tube, each projection 211 being configured to engage an apex of a proximal prong of the expander. The manner of operation is the same as that described with reference to the embodiment of FIGS. 29 to 31, with the exception that the jig engages the expander enabling the ejection element both push and pull the expander along the delivery tube. This enables a surgeon partially eject the expander into the body lumen and then retract the expander if they feel that it is not in the correct position.
[0168] Referring to FIG. 33A to 33D, there is illustrated a delivery device of the invention 300 in use delivering an expander of the invention 1 into the prostatic urethra 10 which is surrounded by the prostate gland 11 and disposed distally of the bladder 301. The delivery device 300 includes a cystoscope 302 disposed concentrically within a lumen of the delivery device 300 and having a distal end substantially flush with a distal end of the delivery tube 202. As shown in FIG. 33A, the expander is mounted within the delivery tube 202 with the cystoscope 302 projecting through a lumen of the expander. The cystoscope comprises a light that illuminates the urethra distally of the end of the delivery device, thereby assisting a surgeon remotely image the urethra prior to deployment of the expander (FIG. 33B), and image the urethra and expander during deployment (FIG. 33C), and after deployment (FIG. 33D), of the expander.
[0169] Referring to FIG. 37, a method of treating benign prostatic hyperplasia (BPH) is illustrated, in which an expander 300 is implanted into the prostatic urethra 310 between the bladder neck 312 and the external sphincter 313. The expander is capable of self-expansion between a radially contracted configuration (not shown, but employed during deployment) and a radially expanded configuration (shown) in which the expander dilates the prostatic urethra thereby relieving the patient of some of the symptoms of benign prostatic hyperplasia, in particular it widens the narrowed urethra, providing less resistance to urine during urination and allows the urine to pass through the diseased prostatic urethra (whereas before it would have encountered a narrowed, high pressure lumen). The expander is configured to fit in the prostatic urethra between the bladder neck 312 and external sphincter 313, so that it does not inhibit the function of either. As ejaculation requires the bladder neck to tonically contract and the external sphincter to spasm, the expander when properly positioned between the bladder neck and external sphincter allows for both of these functions, and thereby addresses one of the drawbacks of known implants for treating BPH, impaired ejaculation and sexual dysfunction. Moreover, as the function of the bladder neck is not compromised when the expander is in-situ, urine does not gather for long periods in the prostatic urethra thereby preventing encrustation of the expander. In addition, the expender is configured such that when deployed in-situ within the prostatic urethra and correctly positioned, blocking of the verumontanum 315 (and subsequent sexual dysfunction) is avoided. To this end, a proximal end of the expander 300 includes a suitably shaped cut-out 316 which prevents the sidewall of the expander 300 coming into contact with the verumontanum 315. In this embodiment, the expander 300 is not restricted to the undulating ring structure of previous embodiments, but may comprise any form of body such as for example the mesh-type bodies commonly employed in stents, or indeed any other type of body that is capable of adjustment between a radially contracted orientation suitable for delivery and a radially expanded orientation capable of dilating the prostatic urethra while allowing flow of urine.
[0170] Referring to FIG. 38, an expander of the invention is shown deployed in the prostatic urethra of a patent with BPH, between the bladder neck muscle and the external sphincter. This figure shows how the device accommodates the verumontanum between two prongs of the expander in the distal prostatic urethra, while the proximal end of the device is configured such that one of the prongs pushes the transition zone of the prostate gland away from the lumen of the prostatic urethra.
EQUIVALENTS
[0171] The foregoing description details presently preferred embodiments of the present invention. Numerous modifications and variations in practice thereof are expected to occur to those skilled in the art upon consideration of these descriptions. Those modifications and variations are intended to be encompassed within the claims appended hereto.
