Penile implant with lengthening cylinder

A penile prosthesis with a two piece inflatable cylinder that provides significant lengthwise expansion of a male penis. The cylinder has an inflatable bellows attached to an inflatable member and a sheath that extends from a base member. The bellows is attached to the base member and the sheath is connected to the inflatable member, such that the sheath will stretch when the bellows is inflated. The sheath surrounds the bellows. The sheath is constructed from an elastic material that can expand up to 100% of its original length. The inflatable member and bellows are connected to a pump which transfers fluid between a reservoir and the cylinder. When fluid is pumped into the cylinder, the bellows and inflatable member are inflated and the sheath is expanded, allowing the inflatable member to move into an elongated position. When the cylinder is inflated the sheath is in tension, wherein the sheath will pull the inflatable member back into a compact position when the bellows is deflated.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to an implantable penile prostheses, and more 
particularly to an extendable penile prosthesis. 
2. Description of Related Art 
Penile prosthesis are typically implanted into a patient to overcome 
erectile impotence. Most penile prosthesis have inflatable cylinders that 
are surgically implanted into the corpora cavernosa regions of the penis. 
The cylinders are typically connected to a pump that transfers fluid from 
a reservoir to the cylinders. 
Prior penile prosthesis include the devices described and shown in U.S. 
Pat. No. 4,009,711 issued to Uson, U.S. Pat. No. 3,954,102 issued to 
Buuck, U.S. Pat. No. 4,235,227 issued to Yamanaka and U.S. Pat. No. 
4,726,360 issued to Trick et al, which disclose simple inflatable 
tube-like cylinders that expand when pumped with a working fluid. The 
cylinders are typically constructed from a nondistensible material and are 
blown up in the same manner as the inner tube of a tire. Unfortunately, 
these devices do not provide much lengthwise expansion of the penis, which 
is part of the natural movement of a normal penis during erection. 
U.S. Pat. No. 4,730,607 issued to Fischell and U.S. Pat. No. 4,718,410 
issued to Hakky, disclose an inflatable cylinder having bellows which 
provides significant elongation of the prosthesis and consequently, of the 
penis, when inflated. However, there is a problem with the retraction of 
the bellows in these devices after use because the rate of retraction is 
dependent only upon the memory of the bellows material such that the 
spring rate of the bellows is low. Therefore, the cylinder of these 
devices does not readily contract when the operating fluid is removed from 
the penis pendulus area of the implant. Such a prosthesis may require 
manual manipulation to fully return the penis into a natural flaccid 
position. Therefore it would be desirable to have an inflatable penile 
prosthesis cylinder that provides considerable lengthwise expansion and 
readily contracts into a natural flaccid position. 
SUMMARY OF THE INVENTION 
The present invention is a penile prosthesis with an inflatable cylinder 
that provides significant lengthwise expansion of a male penis. The 
cylinder has a proximal end which is generally a rigid, solid, tapering 
cylindrical base member and a distal end comprising an inflatable member. 
The cylinder wall comprises, in its mid-portion between the distal and 
proximal ends, an inflatable bellows which attaches at one end to the base 
member and the other end to the inflatable member. Disposed over the 
bellows is a sheath that similarly attaches to the base member and 
inflatable member. When the bellows is in its retracted position, the 
sheath is likewise relaxed and not stretched. When the bellows is expanded 
during inflation thereof, the sheath will stretch. The sheath is 
constructed from an elastic material which can typically expand up to 100% 
of its original length. 
The inflatable cylinder is connected to a pump, which transfers fluid 
between a reservoir and the cylinder. When fluid is pumped into the 
cylinder, the bellows and inflatable member are inflated and the sheath is 
expanded, allowing the distal end to move distally into an elongated 
position. When the cylinder is inflated the sheath is under tension. When 
deflated, the sheath will pull the distal end back into a compact 
position. The spring rate of the sheath is relatively high, so that the 
cylinder readily contracts the penis into a natural flaccid position. 
Therefore it is an object of this invention to provide a penile prosthesis 
which has an inflatable cylinder that provides significant penile 
expansion. 
It is also an object of this invention to provide a penile prosthesis which 
has an inflatable cylinder that provides significant penile expansion and 
readily contracts the penis into a natural flaccid position.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings more particularly by reference numbers, FIG. 1 
shows a penile implant 10 of the present invention. The implant 10 has a 
pair of inflatable cylinders 12 attached to a pump 14, which transfers 
fluid 16 between a reservoir 18 and the cylinders 12. The pump 14 is 
connected to the cylinders 12 by a pair of first tubes 20 that extend into 
ports 22 formed in the cylinders 12. The reservoir 18 is attached to the 
pump 14 by a second tube 24. The tubes 20 and 24 are preferably 
constructed from either nylon or a silicone rubber, which provide 
flexibility and protection from contamination. In the preferred 
embodiment, the reservoir 18 is constructed from a polyurethane that is 
flexible enough to be implanted into the pelvic cavity of a patient and 
compatible with a human body without substantial risk of rejection in a 
typical patient. The elastic nature of the reservoir 18 also allows the 
bag 18 to contract and expand when fluid is transferred to and from the 
cylinders 12. 
The pump 14 is preferably constructed from a silicone elastomer, which can 
be easily squeezed by the user and has enough resiliency to return to the 
original state when released. The pump 14 has a valve (not shown) which 
allows one directional fluid flow into the cylinders 12, when the pump 
housing 26 is squeezed in and out by the user. The valve prevents fluid 
from flowing out of the cylinders 12 when the cylinders 12 are in an 
extended position. Manual manipulation of the pump 14 can open up the 
valve, so that fluid can flow from the cylinders 12 back to the reservoir 
18. 
FIGS. 2 and 3 show a preferred embodiment of the cylinder 12. The cylinder 
12 has a bellows 28 attached to an inflatable member 30. The inflatable 
member 30 and bellows 28 have an inner cavity 32 that can be filled with 
fluid. The bellows 28 is surround on its exterior by an elastic sheath 34 
which extends from a base member 36, and is attached to the inflatable 
member 30 connecting the inflatable member 30 to the base 36. The base 
member 36 is constructed from a silicone elastomer and is rigid enough to 
anchor the cylinder 12 into the root end of the corpus cavernosum. The 
base member 36 also has a bore 39 that provides fluid communication 
between the inner cavity 32 and the port 22. The port 22 and bore 39 allow 
fluid to flow between the inner cavity 32 and the pump 14. 
FIG. 2 shows the cylinder 12 when the fluid within the inflatable member 30 
and bellows 28 is at a relative zero pressure. Operation of the pump 14 
causes the fluid pressure within the cylinder 12 to increase, so that the 
bellows 28 expands and the inflatable member 30 moves in the axial 
direction, as shown in FIG. 3. The inflatable member 30 is preferably 
constructed from a distensible material such as polyurethane between 0.013 
and 0.019 inches thick. The distensible material allows the inflatable 
member 30 to expand and grow in both the axial and radial directions, 
thereby increasing the length and girth of the penis pendulum. 
In the preferred embodiment the bellows 28 is constructed from a silicone 
elastomer that allows the bellows 28 to expand when the fluid reaches a 
predetermined pressure. The sheath 34 is preferably constructed from a 
silicone elastomer that is approximately 0.015 inches thick and can be 
stretched up to 100% of the unstressed length. The sheath 34 has a 
resilient memory and a high spring rate, so that when the fluid pressure 
within the cylinder 12 is reduced, the sheath 34 pulls the inflatable 
member 30 toward the base 36 until the cylinder 12 is in the retracted 
position shown in FIG. 2. 
FIGS. 4-8 show a preferred method of assembling the cylinder 12. The 
cylinder 12 initially comprises two pieces, wherein the bellows 28 is 
attached to the inflatable member 30 and the sheath 34 extends from the 
base member 36. As shown in FIGS. 5 and 6, the sheath 34 is rolled up and 
a stem 38 of the bellows 28 is inserted into a groove 40 in the base 36. 
As shown more clearly in FIGS. 2 and 3, the groove 40 has protrusions 42 
that pinch the stem 38, so that the bellows 28 cannot be easily removed 
from the base 28. The protrusions 42 also seal the inner cavity 32 from 
the area between the bellows 28 and the sheath 34. A vacuum is then 
created in the inner cavity 32 to contract the bellows 28 into a 
compressed position as shown in FIG. 7. An uncured adhesive 44, preferably 
a fumed silica, is placed on an annular groove 46 formed at the interface 
of the bellows 28 and the inflatable member 30. The sheath 34 is then 
unrolled and pulled over the bellows 28. The cylinder 12 is left in that 
state until the adhesive 44 cures and bonds the sheath 34 to the 
inflatable member 30. The vacuum is then removed so that the bellows 28 
returns to the normal position shown in FIG. 8. 
FIG. 9 shows a penile prosthesis 10 of the present invention implanted into 
a patient. Installation of the prosthesis 10 can be performed by any 
surgical procedure known in the art. The preferred method is to make an 
incision at the pelvic bone near the scrotum. The corpus cavernosa are 
then dilated and the cylinders 12 are inserted within the penis. Although 
two cylinders are shown, it is to be understood that only one cylinder 12 
can be used in the present invention. The pump 14 is placed into the 
scrotal sac and the reservoir 18 is inserted into the abdomen. The 
cylinders 12 are placed within the penis such that the bellows 28 are 
completely within the pelvic cavity when the penis is in the flaccid 
position. In this manner the bellows 28 are not physically apparent to the 
touch when the penis is in the normally flaccid position. 
To operate the prosthesis 10, the user squeezes the pump 14 inside the 
scrotal sac to increase the fluid pressure within the cylinder 12. The 
pumping action causes the inflatable member 30 and bellows 28 to expand, 
thereby increasing the length and girth of the penis. In the preferred 
embodiment the operating pressure is approximately 12 psi. The amount of 
extension is approximately 3 cm and the amount of increased girth is 
approximately 30%, both dimensions depending upon the anatomical 
proportions of the patient. The yield pressure of the sheath 34 is 
approximately 12 psi, such that the cylinder 12 does not create 
significant length extension until the yield pressure is obtained within 
inner cavity 32. This construction prevents lengthening of the penis upon 
accidental squeezing of the pump 14. When the desired length is achieved, 
the pumping operation is desisted, wherein the penis remains in an erect 
position as shown in FIG. 10. When an erection is no longer desired, the 
pump 14 is manipulated so that the fluid within the cylinder 12 can flow 
back into the resevoir 18, to allow the penis to return to the flaccid 
position shown in FIG. 9. 
Pumping fluid into the cylinder builds up the fluid pressure within the 
cylinder 12 to a level higher than the pressure in the reservoir 18, so 
that when the pump valve is opened the fluid will have a tendency to flow 
back into the reservoir 18. The elastic spring characteristic of the 
sheath 34 pulls the inflatable member 30 toward the base 36. Consequently, 
the spring force of the sheath 34 creates a reverse pressure within the 
inner cavity 32, to accelerate the flow of the fluid into the reservoir 
18. The reverse pressure created by the sheath 34 is large enough to 
overcome the static head pressure, which may exist because the reservoir 
18 is typically at a higher elevation than the cylinders 12. The sheath 34 
insures that the cylinders 12 move all the way back into the retracted 
position and are not partially extended because of the static head 
pressure created by the elevation of the reservoir 18. 
While certain exemplary embodiments have been described in detail and shown 
in the accompanying drawings, it is to be understood that such embodiments 
are merely illustrative of and not restrictive on the broad invention, and 
that this invention not be limited to the specific constructions and 
arrangements shown and described, since various other modifications may 
occur to those skilled in the art.