CA2195215C

CA2195215C - Malleable penile prosthesis

Info

Publication number: CA2195215C
Application number: CA002195215A
Authority: CA
Inventors: Mark S. Chace; Charles C. Kuyava; John W. Westrum, Jr.
Original assignee: American Medical Systems LLC
Current assignee: American Medical Systems LLC
Priority date: 1994-08-08
Filing date: 1995-07-31
Publication date: 2002-01-29
Anticipated expiration: 2015-07-31
Also published as: JPH09509871A; CA2195215A1; AU2935295A; ATE186194T1; AU683399B2; EP0774935B1; ES2141364T3; US5512033A; DE69513181D1; DE69513181T2; JP3009226B2; US5553379A; WO1996004865A1; EP0774935A1; MX9701008A

Abstract

A malleable penile prosthesis adapted to be implanted in a corpus cavernosum of a penis comprising an elongated core (1) which is bendable about its longitudinal axis with the capability of holding the configuration to which it is bent and is substantially rigid when in the unbent straight configuration, a sleeve (4) of braided biocompatible material, having an inner surface and an outer surface, enveloping the core with the inner surface of the sleeve in contact with the core and t he sleeve and core being accommodated within an outer tube (8) of elastomeric material, which tube has a substantially rounded smooth outer surface and an inner surface having a profile formed of alternate grooves (14) and ribs (15) in a substantially helical arrangement. A method of forming a malleable prosthesis is also disclosed.

Description

wo s6/04865 2 1 9 5 2 1 5 This invention relates to a malleable penile prosthesis. More particularly, the invention is concerned with a penile prosthesis comprising a malleable core enveloped t in a sleeve, which sleeve and core are 6C~,v~ ' ' ' within an outer tube of .,~,,iu material. The invention also relates to a method of making a malleable 10penile prosthesis. All the materials used in the prosthesis are Livcc,,,,u_'ible.
As used herein the temm ~malleable' means bendable, with the capacity of holding the resulting configuration until a subsequent step of bending or ~I"~I ,t~:"i"g is perfommed. The malleable core of the prosthesis of this invention ' "" )~1:) has the ch_.c.~.l.,,i,iic of being substantially rigid when not being subjected to bending, and 15particularly when in the unbent straight cu"19 l ,.
Impotence or inability to achieve penile erection is quite prevalent and many solutions have been proposed and are available in the art to cure or cc"",u~"__'.u for the condition. In particular, various types of penile prostheses are Cvl"..,t"~ 'Iy available.
20The majority of penile prostheses fall into two types. These two types are theinflatable, ;~,u'_,lt~Llu prosthesis and the simple i,..~ ,lt~Lle inherently stiff or substantially rigid prosthesis. The inflatable prosthesis Is normally implanted in pairs withil~i the corpora cavennosa and connected to hydraulic pumping means, also implanted within the patienrs body, which means enable the prosthesis to be inflated 25 for erection and deflated for flaccidity. The simple or non-inflatable, prosthesis is also generally implanted in pairs in the corpora cavemosa and, in view of its inherent stiffness, provides a generally constant erection. Hence, it is desirable to provide pc ~,a;vn ' "~i so that the erection may be at le&st ~artially concealed by the patient.
r. n ~ ~y iS generally achieved by making the simple prosthesis bendable or 30 malleable and the prosthesis provided by the present invention is of this simple type, herein designated as a malleable prosthesis.
A number of prior art prostheses deal with the requirement of F ~ y by '' providing various forms of ss".. :"tt,d or articulated structures. Such stnuctures are disclosed, for example, in U.S. Patent Nos. 4,665,902; 4,666,428 and 4,807,608 and 35 4,881,531.

Wo 96/04865 Another form of F~ " ,GLle prosthesis comprises an t:l~lu,,,_,iu rod and a metal wire coil coaxiaily embedded within at!east a portion of the rod, as disclosed in U.S. Patent No. 4,669,456.
U.S. Patent No. 4,392,562 discloses a limited bend malleable penile prosthesis t 5 comprising an elongated maileable element having bend limiting means comprising a plurality ot _. ,,u~cl,u,_~le adjacent elements positioned in co-operative j~ p~ n with said malleable element.
U.S. Patent No. 3,987,789 discloses a malleable penile prosthesis comprising an elongated malleable rod portion housed within a generaily tubular, ~ ulogi~ A'IJ
10 inert plastic body; and U.S. Patent No. 4,594,998 discloses a similar type of prosthesis but having a somewhat more elaborate and improved structure.
U,S. Patent No. 4,988,357 discloses a penile prosthesis comprising an b~ t~ flexible rod member fommed by a core porbon comprising a plurality of metailic wires, typicaily high-purity silver, and an outer casing comprising ;"",1_., ' ' 15 plastic materiai around the core portion.
It has now been found that an improved maileable penile prosthesis of the type having a malleable core ac~,u",... ' ' within a tubular sheath may be provided as hereinafter described, which prosthesis has improved F ", ' ty and improved F~l l.,l l l l~.. I,~e.
In accu"J.. ,ce with the invention there is provided a malleable penile prosthesis :
adapted to be implanted in a corpus cavemosum of a penis comprising an elongatedcore having an unbent straight cu"qg ~ _ ~ about a longitudinal axis, a distai end and a proximai end, which core is bendable about said axis with the capability of holding a ~,u~ ,q_ ~ to ~,vhich it is bent and is substantially rigld when in the unbent straight 25 ~,u"q~ " a sleeve of braided L: ., ' ' material, having an inner sur~ace and an outer surface, enveloping said core with the inner surface of the sleeve in contact with the core and an outer tube of s' "." i.. material containing the sleeve and core, said tube having a wall with an outer surface and an inner surface, a distai end and a proximal end, each of said ends having a substantiaily rounded smooth outer surface, 30 said outer surface of the wail being substanUally smooth and said inner surface having a prolile fommed of aitemate grooves and ribs in a substantially helicai GllClllU~Ille,,i.
In n preferred e. . li u-li" ,~"t of the prosthesis according to the invention the core is formed from a pluraiity of metai wires, especiaily stainless steel wires, twisted wo s6/04s6s 2 1 9 5 2 ~ 5 together and secured at each end with a solid metai cap to form an integral malleable element.
Preferably the sleeve enveloping the core comprises a pluraiity of layers, preferablythree,ofbraidedpolymericmaterial. Whiletheoutsidediameterotthesleeve 5 is matched with the internal diameter of the outer tube as defined by the crests of the ribs in the inner surface of the wall of the outer tube, there is a smail clearance, of the order of 0.010 to 0.050 inch, between the outer surface of the sleeve and the surfaces of said crests when the prosthesis is in a straight configuration. The stated surfaces tend to come into contact with each other when the prosthesis is subjected to bending.
10 The small clearance contributes toward F ~ , ' ty without kinking.
A preferred material for the braided sleeve is a biu~.u,,l~,~.'ible polyester, particulariy F 9y_ h~l ,e ~ htl l ' The invention aiso provides a method of forming a malleable penile prosthesis comprising an elongated core, a sleeve enveloping said core and an outer tube 15 accu""" ' ,g said sleeve and core, which method comprises forming said core, enveloping said core with a sleeve of braided i,iu.,u,, ,, ' material, forming a tube of ' i~. material having a wall with an inner surface and an outer sur~ace and a bore definQd by the inner surface of the wall, which inner surface has a profile fommed ot aiternate grooves and ribs in a substantially helical ~,,u ~y_..~_. ,t, and inserting said sleeve and core within said bore so that the crest of each rib is matched closely to the outer surface of the sleeve. The close matching of the outer surface ot the sleeve with the inner surface ot the outer tube so as to leave a small clearance between said surfaces when the prosthesis is In a straight co"99 1 r, provides a prosthesis with column strength" , ' ty and naturai feel.
In perfomming the method of the invention the elongated core is preterably tormed by twisting together a pluraiity ot metai wires, initiaily positioned in side-by-side longitudinal ,~' nsl,i~,, to form a substantially rigid but bendable integral bundle having a distai end and a proximai end, and securing the integrity cf said core by ~' crimping a solid metal cap to each end ot the twisted bundle ot metal wires.
Preferably, the sleeve ot braided material comprises a pluraiity ot layers ot braided polymeric materiai and the sleeve is positioned around the core by braiding the layers, preterably three, tightly around the core to torm an integral sleeve in intimate contact with the core.

WO 96/04865 I ~

The prosthesis of the invention comprises, in cor"Li"~lion, a malleable core enveloped in a sleeve of braided material and an outer tube of el.~ llelk, materiai having an internal surface with a distinctive profile.
Although a fewer number of wires with consequential larger diameter may be 5 used, in a preferred u.oLOdi",e~t the core is made by twisting together a pluraiity of metal wires, for example from 100 to 150 wires, each having a diameter of from 0.006 to 0.010 inch. A particularly preferred o..lLOdi",e,lt comprises a core made trom 134 wires of stainless steel, each having a diameter of about 0.008 inch.
The metal wires are typically made by drawing and usually are of circular cross-10 section, both for ease of fabrication and interactive contact. However, othercu"9~, ~ ,s, for example, unifomm hexagons, are possible, providing the resulting bundle has the required F ~ " , ' "'y af~er twisting.
Twisting of the bundle of wires is necessary to provide ~ " r, ' "ty without kinking or other distortion and to overcome resistance to bending. The proper degree 15 ot twisting to achieve optimum F ~ y and cycle life may be detelll ,i, led by the lay of the wire and is preferably of the order of 1.45 to 1.65 inches.
~ Stainless steel is the metai of choice for the wires over other metais or ailoys which might be used because it possesses a cv"lLi" h of desirable .,I, ..~,le,iDli....
Thus, it is prefenred over, for example, silver, tantalum, an alloy of titanium, aiuminum 20 and vanadium, and chromium-nickel super alloy, which metals and alloys have been suggested for malleable prostheses.
The other metals and alloys mentioned above tend to exhibit elther more wire-to-wire gailing, i.e., friction interaction, than stainless steel, or other loss in p "' , ' "'y and/or cycie life.
26 The prefenred twisted wire core described above has better wire-to-wireinteraction than previous ~ ' " in _.,_._ ,9 metal wires. By using a greater number of wires, of smailer diameter, than used hitherto and controlling the degree of twist of the wires with little work-hardenin,q a great L,,~u,.:. d in Fr , ' "~ is obtained. This, together with increased wire-to-wire contact while ",~.,' ,i"g an extended cycle life provides an improved malleable core.
The malleable core is enveloped in a sleeve of braided material, preferably a L;OCG~ U--I;LIe polyester, such as F B yelhy'. .,,D ~ Jh tl, '..t~,.

Wo96/04865 2 1 ~ 5 2 1 5 .~1~1, s .

ln a preferred elllLOdi",~ "I the braid is formed from a yam of about 200-250 denier, 50 filament, 2-ply braided on 16 carriers having 43-50 picks per inch with improved tightness over prior braids. The sleeve preferably comprises three layers of the braid, and the new sleeve is a distinct ;~ over prior art sleeves.
J . 5 The core enveloped in the sleeve is accu" " " ' ' within an outer tube made of: ' ,t" k, materiai, for example, silicone nubber. The outer tube has a distal end and a proximal end, each of which has a substantially rounded smooth outer surface.
The outer tube defines a central longitudinal bore which, to facilitate formation of the prosthesis, initially has an open side port set back from the distal end and is open at the proximal end. The proximal open end allows insertion of the core and sleeve therethrough, as well as withdrawal of the groove-forming mandrel, which withdrawai is aided by the open side port, as hereinafter described. After formation of thsprosthesis the open side port and proximai open end are seaied by filling with asilicone adhesive.
The outer tube has a wail with a substantiaily smooth outer surface and an innersurface having a profile fommed of aitemate grooves and ribs in a substantially helical ~ L When the sleeve-covered core is &CCullllll_ ' ~ ' within the outer tube there is a small clearance between the crest of each rlb on the inner surface of the wail of the tube and the outer surface of the sleeve. When the prosthesis is subjected to 20 bending each crest in the proximity of the bend tends to come into touching contact with the outer surface of the sleeve. The preferred manner in which the grooves and ribs are formed on the inner surface of the wail of the outer tube is described hereinafter.
Preferred ~."i~Odi"n:";~ of the invention are illustrated in the acc~""~,_.,y;.,g 25 drawings, in which:
Fig. 1 is a side elevation, partly in section, of one e:"lLOdi",~"~t of a prosthesis according to the invention;
Fig. 2 is an enlarged sectional side view of the distai portion of the e"lLo ii..,.",l of Fig. 1;
Fig. 3 is an enlarged sectional side view of the proximal portion of the c..-Lodi..,.",t of Fig. 1;
Fi~. 4 is an enlar~ed sectional side view of an altemative version of the distalportion of a prosthesis according to the invention;

W096/04865 r. ~
21952~5 Fig. 5 is a cross-sedion, partly enlarged, through line V-V of Fig. 1 without the outer sheath;
Fig. 6 is a view ot the inside of the outer tube of the ~"~Lod;"~ t of Fig. 1 showing the helical ~u~,gt""~"l of the ribs and grooves;
6 Fig. 7 is a side elevation, partly in section of the core and sleeve during fommation thereof;
Fg. 8 is a side elevation, partly in section, of another ulllLo.li,,,, "1, and hg. 9 is a side elevation of a mandrel used in the formation of the e",Lod;..,~"t of Fig. 8.
Fig . 1 of the acc-," ",.. ,J;. ,g drawings illustrates one ~" ILodi, "_. ,t of a prosthesis according to the invention. The prosthesis comprises a central core 1 extending about the longitudinal axis of the prosthesis.
The core is made from a plurality of metal wires twisted together and secured to form an integral element by metal caps at the distal end 2 and proximal end 3 of the 1 6 core.
The metal wire malleable core 1 is enveloped in a sleeve 4 (See Fig. 2, 3 and 4) made up from three layers of braided material, preferably a polyester much aspolyuth,' ,e l~ yl,tl ' ' As shown in Fig. 7 the three layers 5, 6, 7 of material are braided around the core ~n situ.
Thec~ vac~,"lL;" " ,is~scc-"""_' ' 'withinanelongatedoutertube8 hnving a substantially rounded smooth surface distal end 9 and a substantially rounded smooth surhce proximal end 10.
The elongated outer tube has a central bore which 6CCul 111.1- ' ' the core and sleeve. The end of the bore at the proximal end 10 of the tube is open during formation of the prosthesis (as described h~,uil '' ) and is closed with a plug of adhesive 11, preferably silicone, when the prosthesis is completed.
The outer surface 12 of the wall of the tube 8 is substantially smooth. In a preferred e"lLo,li..,u"l of the invention the outer tube is enveloped in an outer sheath 13 of t' ' ,~ material. This outer sheath is useful for increasing the 30 diameter of the prosthesis. The inner surface of the wall of the tube has a profile formed of a!ternate grooves 14 and ribs 15. There is a small clearance 16 (Fig. 2) between the crest of each rib and the outer surface of the sleeve 4 and this clearance allows bending and ~ ht~,,i,,9 of the prosthesis without kinking of the wire bundle W096/0~865 2 1 9;2 1 5 P~,ll..,,_,~' while restricting bending to a desirable limit. The alternate grooves 14 and ribs 15 are formed in a substantially helical ~,~.~ "" "l as illustrated for example in Fig. 6.
The outer tube 8 is made from a moldable elastomer, for example a silicone rubber, and the groove/rib profile is formed by c,."~ si ", moulding over a pre-formed mandrel at an elevated temperature, for example, about 117~C.
The helical grooves are preferably at an angle of about 45 ~ and are formed froma seven stalt mould mandrel which provides a seven-start structure of helical grooves, which has been found to be the optimum number for longitudinal rigidity and lateral strength. The width and depth of the grooves and ribs are balanced so as to provide optimum stiffness and bendability and the helical profile gives a more natural feel to the prosthesis without detracting from the bendability.
The braided sleeve contributes to the F - , ~ of the malleable core, and the use of three layers in the braid has been found to be enough to contain the wires in the core and to match the outer diameter of the sleeve with the inner diameter of the 16 helix, defined by the crests of the ribs.
Refening to Fig. 7 of the drawings the malleable core is fommed by u " ,9 a plurality of metal wires, preferably about 134 wires of stainless steel, each having a diameter of about 0.008 inch, in side-by-side " I,I ,i~, fomming each end of the wire bundle into a loop 17 to enable the assembly to be connected to a suitable twisting apparatus, for example a lathe, so that the wires may be twisted together.
When the desired degree of twisting for optimum pclf .""~ce has been achieved, the core is removed from the twisting apparatus, the sleeve is braided around the core and the loops at each end are removed so that each end may be capped tosecure the twisted wires.
The sleeve covered core 1 is then inserted into the central bore of the outer tube through the open end at the proximal end of the tube and the open end is then closed with a plug of adhesive silicone 11 to complete the desired prosthesis.
A preferred: ~nt of the prosthesis according to the invention is illustrated in Fig. 8. In this ~" ,bodi" ,_"l the various features are substanUally similar to thoseofthee",Lo.li",,"lillustratedinFig. 1 butthehelicalcu,G"~p"" ",1ofgrooves 18 and ribs 19 is slightly modified.
The grooves and ribs of the outer tube of the :" Ibo.li", "t of Fig. 8 are formed by moulding about a mandrel 20 such as that illustrated in hg. 9. The mandrel Wo 96/04865 : 21 9~21 5 comprises an elongated groove and rib forming main portion 21, a distal end portion 22 end e proximal end portion 23.
Theoutertubeisformedbycu,,,~ ,siul)moulding,atanelevatedtemperature of a suitable . ' "el i-, polymer, for example, silicone rubber, over the mandrel. The 5 moulding operaUon fonms the outer tube with a longitudinal bore which matches the profile of the mandrel wherein the inner surface of the central portion has a helical ~, .,"5~c,, "~."1 of grooves and ribs. The moulded tube is provided with an open hole or port 24 in a side wall of the distal portion. In an altemative e"lLodi",~ "I, as illustrated in Fig. 4, the hole or port 25 extends dio ~l~bi-,all~ across the tube. The bore has an 10 open end 11 at the proximal portion of the tube, formed by the proximal portion 23 of the mandrel.
When the mouldins operation is completed an air pipe is attached to Uhe hole 24 or 25 and the bore is distended by air pressure so that the mandrel may be removed through the open proximal end of the bore, and the formed outer tube is then allowed 15 to cool. The malleable core and sleeve Is then placed In the bore and anchored to prevent Internal twisting by adhesive 26 at the distal end and adhesive 27 at the proximal end. The holes 24 or 25 at the distal end and the hole 11 at the proximal end are filled with adhesive to complete the formaUon of the prosthesis.

Claims

CLAIMS:
1. A malleable penile prosthesis adapted to be implanted in a corpus cavernosum of a penis comprising an elongated core having an unbent straight configuration about a longitudinal axis, a distal end and a proximal end, which core is bendable about said axis with the capability of holding a configuration to which it is bent and is substantially rigid when in the unbent straight configuration, a sleeve of braided biocompatible material having an inner surface and an outer surface enveloping said core with the inner surface of the sleeve in contact with the core and an outer tube of elastomeric material containing the sleeve and core, said tube having a wall with an outer surface and an inner surface, a distal end and a proximal end, each of said ends having a substantially rounded smooth outer surface, said outer surface of the wall being substantially smooth and said inner surface having a profile formed of alternate grooves and ribs in a substantially helical arrangement.
2. The prosthesis according to claim 1, characterized in that the core is formed from a plurality of metal wires twisted together and secured at each of said core distal end and core proximal end with a solid metal tip to form an integral malleable element.
3. The prosthesis according to claim 1 or 2, characterized in that the sleeve comprises a plurality of layers of braided polmeric material having an outside diameter which matches an internal diameter defined by crests of the ribs in the outer tube, said crests having surfaces, a small clearance being provided between the outer surface of the sleeve and the surfaces of said crests when the prosthesis is in a straight configuration.

4. The prosthesis according to any one of claims 1 to 3, characterized in that the core comprises about 100 to 150 wires of stainless steel each having a diameter of from about 0.006 to 0.010 inch, twisted together and being enveloped in a sleeve comprising at least three layers of braided polyester.
5. The prosthesis according to any one of claims 1 to 4, characterized in that the grooves in the inner surface of the wall of the outer tube are defined by a seven-start structure of helical grooves having a helix angle of about 45À and the elastomeric material of the tube is silicone rubber.
6. The prosthesis according to any one of claims 1 to 5, characterized in that an outer sheath envelopes the outer tube.
7. A method of forming a malleable penile prosthesis comprising an elongated core, a sleeve enveloping said core and an outer tube accommodating said sleeve and core, characterized in that the method comprises forming said core, enveloping said core with a sleeve of braided biocompatible material, forming a tube of elastomeric material having a wall with an inner surface and an outer surface and a bore defined by the inner surface of the wall, which inner surface has a profile formed of alternate grooves and ribs in a substantially helical arrangement, and inserting said sleeve and core within said bore.
8. The method according to claim 7, characterized in that the elongated core is formed by twisting together a plurality of metal wires, initially positioned in side-by-side relationship, to form a substantially rigid, bendable, integral bundle having a distal end and a proximal end, and securing the integrity thereof by crimping a solid metal cap to each end of the bundle.

9. The method according to claim 7 or 8, characterized in that a sleeve comprising a plurality of layers of braided polymeric material is positioned around the core by winding the layers tightly around the core to form an integral sleeve in intimate contact with the core.
l0. The method according to any one of claims 7 to 9;
characterized in that the core is made from stainless steel wires and the sleeve is formed by braiding three layers of polyethylene terphthalate yarn around the core.
11. The method according to any one of claims 7 to 10, characterized in that the bore of the outer tube is formed by compression moulding the material of the tube about a pre-formed mandrel at an elevated temperature, distending the bore by air pressure applied through a hole in the distal portion of the tube and thereby removing the mandrel and allowing the resulting moulded formation to cool.
12. The method according to any one of claims 7 to 11, characterized in that the external diameter of the prosthesis is extended by enveloping the outer tube within a sheath of elastomeric material.