Manually actuated hydraulic sphincter having a mechanical actuator

An implantable hydraulic urinary sphincter system is disclosed for maintaining continence in those patients unable to control or stop inadvertent urinary flow. The invented apparatus generally consists of an artificial urinary sphincter and a control means for automatically increasing or decreasing sphincter pressure with sensed bladder and/or intra-abdominal pressure. An improved mechanical actuation means is also disclosed which allows the patient to urinate. To urinate the patient presses a push button centered on a septum located on the outer wall of the subcutaneously implanted control unit.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The invention relates to an artificial sphincter for maintaining continence 
in those patients unable to control or stop inadvertent urinary flow. More 
particularly, the invention relates to a hydraulic sphincter which: 
automatically causes sphincter pressure to increase or decrease with 
sensed bladder pressure and/or intra-abdominal pressure; is manually 
actuated by the patient when he or she desires to urinate; and, allows 
sphincter fluid pressure to be measured and adjusted after implanation 
without necessitating a surgical procedure. 
2. Description of the Prior Art 
Urinary incontinence is a ubiquitous disorder which represents more than a 
personal inconvenience and social problem. For many, particularly those 
individuals suffering spinal injury, incontinence can cause life 
threatening complications. In the United States alone, it is estimated 
that 100,000 persons of all ages, many of them young veterans, have 
sustained spinal cord injuries rendering them incontinent. Pyelonephritis, 
a kidney infection produced by bacterial spread from the lower urinary 
tract, has been the leading cause of death among paralyzed World War II 
and Korean war veterans. Neurologic dysfunction of the urinary spincter 
can also occur because of multiple sclerosis, stroke, cerebrovascular 
disease, Parkinson disease and diabetes. Approximately 20% of the 
population over 65 suffer from incontinence. Women suffer "stress 
incontinence" largely the result of changes in bladder geometry following 
child birth. Many men experience incontinence after prostate surgery. 
Finally, incontinence can result from meningomyelocoele, amyotrophic 
lateral sclerosis, spinal cord or brain tumor, head injury, herniated 
disc, syringomyelia and tabes dorsalis. 
Various attempts have been made to artificially produce urinary continence. 
Early attempts to prevent male incontinence involved externally clamping 
the penis; but, pressure sufficient to stop urinary flow tends also to 
compromise circulation, causing pain, skin alteration and thrombosis. An 
analogous application for women, compressing the urethra between the 
vaginal wall and the pubic bone, shares these disadvantages. 
Several implantable artificial sphincters have, more recently, been 
disclosed in the prior art. U.S. Pat. No. 4,156,093 issued to Curtis Helms 
et al teaches the use of a fluid filled urethra collar which is contracted 
by manually squeezing a bulb implanted in the scrotum. In an article 
entitled "Implantation of an Artificial Sphincter for Urinary 
Incontinence" by F. B. Scott et al, in Contemporary Surgery, Vol. 18, Feb. 
1981, results with such prior art artificial sphincters are reported. The 
article focuses on typical prior art devices which require a bulbous pump 
to be implanted in the scrotum of the male or in the labium of the female. 
In order to initiate urine flow the patient must compress the bulbous 
pump. The prior art devices are psychologically and cosmetically 
undesirable because of a general aversion most patients have to touching 
implants in such sensitive portions of the bodies as the scrotum and 
labium. 
U.S. Pat. No, 3,815,576 issued to Donald R. Balaban teaches the use of a 
fluid filled flexible container implanted in the patient which is squeezed 
manually to actuate a piston-cylinder in a U-shaped clamp. Similarly, U.S. 
Pat. No. 4,056,095 issued to Pierre Rey et al and U.S. Pat. No. 4,0178,915 
issued to Gerhard Szinicz et al teach the use of a fluid filled artificial 
sphincter which is actuated by pressing on the subcutaneously implanted 
membrane. These references share the disadvantage of having no control 
over the pressure exerted by the artificial sphincter on the urethra once 
the apparatus is implanted. 
During the course of a research study (G. Timm et al), "Experimental 
Evaluation of an Implantable Externally Controllable Urinary Sphincter", 
Investigative Urology 11:326-330, 1974) it was found that artificial 
sphincter cuff pressure of 40 cm of H.sub.2 O and above produce necrosis 
(tissue death) of the urethra. As a result, the prior art devices 
generally operate at a cuff pressure below 40 cm of H.sub.2 O. However, 
the normal bladder (and also the hypertrophic bladder), can produce high 
pressure transients, which result in dribbling incontinence for patients 
with these devices. U.S. Pat. No. 3,744,063 issued to McWhorter et al 
teaches controlling the flow of a fluid into the sphincter so that 
pressure applied to the urethra is graduated and controlled. However, 
variable pressure is controlled manually by applying digital pressure to 
an implanted pump chamber. Presumably, the patient increases the sphincter 
pressure after dribbling incontinence has occurred and been detected. The 
patient would not be able to respond to rapid changes in bladder pressure 
caused by bladder spasms, voluntarily or involuntary tensing of the 
diaphragm or abdominal wall, or increased intra-abdominal pressure due to 
walking, sitting, coughing or laughing. 
The August 1981 issue of Urology Times contains an article reporting on an 
address by Dr. T. R. Malloy of the Pennsylvania Hospital in Philadelphia. 
Dr. Malloy has discovered that to reduce necrosis of the urethra it is 
necessary to have the artificial sphincter unfilled upon initial implant. 
It was found that urethra tissue swells immediately after surgery. If the 
artificial sphincter is filled it will exert an excessive pressure on the 
swollen urethra resulting in tissue necrosis. Dr. Malloy recommends 
allowing the swelling to decrease, followed by a second operation at a 
later time, merely to fill the sphincter chamber with fluid. The prior art 
artificial sphincters have no way of adding or replacing fluid in the 
artificial sphincter without surgery. Therefore, successful implantation 
of prior art devices require two separate surgical operations. 
SUMMARY OF THE INVENTION 
In copending U.S. patent application (Ser. No. 421,441, filed 9/21/82, now 
U.S. Pat. No. 4,571,749,), entitled "Manually Actuated Hydraulic 
Sphincter", which is incorporated herein by reference, Applicant disclosed 
a Manually Actuated Hydraulic sphincter (MAHS) which automatically 
increases sphincter pressure above a minimum pressure in accordance with 
sensed bladder and/or intra-abdominal pressure. The present patent 
application discusses many of the features previously disclosed in the 
above-referenced application plus new features which have been 
incorporated into the (MAHS) apparatus. 
The apparatus generally consists of: a subcutaneously implanted control 
unit; an artificial sphincter that is hydraulically coupled to the control 
unit; and, a sensor bulb implanted at a selected site and also 
hydraulically coupled to the control unit. The implanted control unit 
includes a minimum pressure means for biasing fluid pressure in the 
artificial sphincter at an adjustable minimal or nominal fluid pressure. 
The implanted control unit also includes a pressure transfer means for 
adjusting fluid pressure in the artificial sphincter depending on pressure 
sensed by the pressure bulb; so that, the fluid filled artificial 
sphincter exerts just enough pressure on the urethra to prevent 
incontinence. The implantable control unit further includes an actuation 
means, manually controlled by applying pressure to an actuation button. 
The actuation means mechanically reduces the fluid pressure in the 
sphincter fluid chamber which in turn reduces the pressure exerted by the 
artificial sphincter on the urethra and thereby allows the patient to 
urinate. 
Bladder pressure or abdominal pressure can increase rapidly because of 
bladder spasm, voluntary or involuntary tensing of the diaphragm or 
abdominal wall, or increased intra-abdominal pressure due to walking, 
sitting, coughing or laughing. If for example, the patient's bladder or 
diaphragm spasms, bladder pressure will increase rapidly. To prevent 
dribbling or stress incontinence the pressure exerted by the artificial 
sphincter on the urethra may be required to exceed diastolic pressure at 
least for that short period of time when the bladder pressure exceeds 
diastolic pressure. Prior art devices, to prevent such dribbling 
incontinence, would have to constantly maintain sphincter pressure above 
diastolic pressure thereby causing necrosis of urethral tissue which is 
permanently damaging. By contrast, the invented apparatus will 
automatically increase sphincter fluid pressure only for the length of the 
spasm, thereby causing no threat of tissue necrosis. The invented 
apparatus therefore can provide continence during bladder pressure peaks 
without causing necrosis of the urethral tissue. The pressure sensing bulb 
can be implanted in the wall of the bladder, thereby directly sensing 
bladder pressure, or it can be placed in the abdomen just below the 
bladder. When at the latter location, the pressure sensed would be that of 
abdominal pressure plus to some extent a pressure that is dependent on the 
extent to which the bladder is filled. Placement in the abdominal area may 
be advantageous if bladder wall surgery is difficult or contraindicated 
for a particular patient. 
An additional advantage of the present invention is that the artificial 
sphincter can be implanted and remain void of fluid until the urethra has 
healed and swelling been reduced. The invention allows fluid to be added, 
after implantation, by inserting a hypodermic syringe through a septum 
into the invented device and adding fluid until an appropriate minimum 
sphincter pressure is obtained. The present invention can, therefore, be 
safely implanted without the need for the repeat operation required in the 
prior art. Furthermore, in the invented device, pressure exerted by the 
artificial sphincter can be measured and controlled at any time after 
implantation. For example, a low sphincter pressure can be initially set 
(e.g., 10 cm of H.sub.2 O above bladder pressure) which minimizes the 
possibility of urethral necrosis. If this pressure is shown to be 
insufficient to maintain continence, it can be increased using a simple 
hypodermic syringe that adds artificial sphincter fluid without requiring 
surgical intervention. If the minimum pressure required to maintain 
continence changes with time in a particular patient, it can be modified 
by adding fluid (to increase sphincter pressure) or removing fluid (to 
decrease sphincter pressure) by means of a hypodermic syringe. Any similar 
adjustment to prior art devices would have required an additional surgical 
operation. 
To provide the above-stated advantages, the control unit contains two fluid 
filled chambers: a sphincter cuff fluid chamber, and a sensor pressure 
reference chamber. The sphincter cuff fluid chamber is hydraulically 
coupled to the artificial urethra sphincter cuff such that pressure 
exerted by the sphincter cuff varies according to the fluid pressure in 
the cuff chamber. The sensor pressure reference chamber is hydraulically 
coupled to the bladder pressure sensor bulb and fluid pressure in that 
chamber increases as the bladder pressure sensor bulb is compressed by 
increased bladder or intra-abdominal pressure. A common wall between the 
two chambers includes a resiliently biased member, such as a bellows. The 
fluid pressure in the artificial sphincter is adjusted to a minimum 
pressure determined by the spring rate of the bellows and the volume of 
fluid that is put into the sphincter cuff chamber. 
A diaphragm/septum, included in the outer wall of the sphincter cuff 
chamber, allows entry of a hypodermic syringe into fluid communication 
with the cuff chamber. By increasing the fluid volume in the cuff chamber, 
the minimum pressure can be adjusted to a desired level. Therefore, the 
hypodermic syringe can inject or remove fluid from the sphincter fluid 
chamber thereby increasing or decreasing the minimum pressure. 
As changes in the bladder or intra-abdominal pressure is sensed by the 
pressure sensing bulb, the resiliently biased member (bellows) located in 
the common wall cooperates with the pressure sensor reference chamber to 
form a pressure transfer means. As pressure increases or decreases in the 
sensor chamber, the pressure transfer means will cause a corresponding 
increase or decrease in the sphincter cuff pressure; so that, the fluid 
filled artificial sphincter cuff exerts just enough pressure on the 
urethra to prevent necrosis. 
To allow the patient to urinate, a separator member is mechanically engaged 
as the patient presses on a push button through the skin and tissue. The 
push button is positioned in a diaphragm/septum located on the outer wall 
of the subcutaneously implanted control unit. As the separator member is 
mechanically engaged it presses on the bellows and decreases pressure in 
the cuff chamber, thus allowing the patient to urinate. This mechanical 
actuator represents an improvement to the hydraulic actuator described in 
the above-cited and copending Fischell patent application (entitled 
"Manually Actuated Hydraulic Sphincter"). The present improved (MAHS) 
apparatus only requires two fluid chambers, which represents a 
considerable simplification in design. The diaphragm function and the 
septum function are now combined into a single, thick, elastomer molded 
part which forms an outer wall of the sphincter fluid chamber. Also, the 
push button makes it easier for the patient to locate the exact center of 
the control unit under his skin, which is the ideal place on which to push 
in order to achieve the greatest volume removal from the cuff chamber with 
the least force. 
The improved (MAHS) apparatus also uses a needle stop located within the 
sphincter fluid chamber at a position beneath the diaphragm/septum. This 
feature allows the adjustment of cuff pressure by adding or removing fluid 
via the hypodermic needle. The needle stop prevents the needle from 
exerting a force on the movable surface (bellows) of the sphincter cuff 
chamber; such force application would cause an erroneous pressure reading 
in the sphincter cuff chamber. 
Still another advantage of the improved (MAHS) apparatus is the use of an 
elastomer band which encompasses the circumference of the control unit. 
The elastomer band satisfies the dual function of: (1) establishing a 
silicone rubber to silicone rubber interface between the band and the 
tubing connecting the control unit to the pressure sensor bulb and the 
sphincter cuff; and (2) providing suturing holes for attaching the control 
unit into the patient's body. 
A first novel feature of the invention is a Manually Actuated Hydraulic 
Sphincter which can prevent incontinency, over a wide range of bladder and 
intra-abdominal pressure, without causing necrosis of the urethral tissue. 
A second novel feature of the invention is the use of a control unit which 
automatically increases sphincter pressure in relation to increases in 
sensed bladder pressure and/or intra-abdominal pressure. 
A third novel feature of the invention is the use of a control unit which 
has a pressure sensing bulb, implanted in association with the bladder, to 
sense bladder and/or intraabdominal pressure. 
A fourth novel feature is the use of a control unit which contains a means 
for adjusting the minimum sphincter fluid pressure level after the unit is 
implanted. 
A fifth novel feature is the use of a manual actuation means which is 
mechanically linked to push button located on the outer surface of the 
subcutaneously implanted control unit. 
A sixth novel feature is the use of a control unit that can be adjusted 
after implantation to set or reset the sphincter fluid pressure. 
A seventh novel feature is the ability to measure sphincter cuff pressure 
after implantation; and the use of a needle stop to prevent a hypodermic 
needle from applying pressure to the movable surface of the sphincter cuff 
chamber, which would cause an erroneous pressure reading. 
An eighth novel feature is that the pressure sensing bulb is expanded each 
time the (MAHS) apparatus is actuated for voiding thus preventing the 
build-up of body tissue encapsulation around the sensing bulb. 
A ninth novel feature is the use of a thick elastomer diaphragm/septum 
which serves the dual function of allowing a hypodermic needle into fluid 
access with the sphincter fluid chamber and also providing a flexible 
diaphragm for use in association with the push button mechanical actuation 
means. 
A tenth novel feature is the use of a elastomer band for: (1) holding 
connecting tubes onto the control unit's body by establishing a silicone 
rubber to silicone rubber connection; and, (2) providing suturing holes 
for attaching the control unit at a preselected subcutaneous location.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows the configuration of the (MAHS) apparatus within a human 
patient. A control unit is shown at 10 which is connected by fluid line 18 
to a pressure sensing bulb 16. Also seen in FIG. 1 is a line 14 connecting 
the control unit 10 to an inflatable cuff 12 which surrounds the patient's 
urethra. The principle of operation of the MAHS device is that when finger 
pressure is exerted through the skin onto push button 21 of the control 
unit 10, the working fluid is removed from the inflatable cuff 12 and the 
patient can void. As soon as the finger pressure is removed from the push 
button 21, urinary continence is restored. The object of the pressure 
sensor 16 is to instantaneously increase the fluid pressure in the cuff 12 
when sensed bladder pressure rises or when abdominal pressure rises 
suddenly, such as by coughing, so that stress incontinence is eliminated. 
FIG. 2 shows a more detailed view of the invented apparatus as implanted in 
a patient. The artificial sphincter cuff 12 is shown surrounding a portion 
of the urethra 20. The artificial sphincter cuff 12 and associated 
pressure line 14 are filled with an incompressible sphincter fluid 22. As 
the pressure of the sphincter fluid 22 is increased or decreased by 
control unit 10, the pressure exerted by the cuff 12 on the urethra will 
correspondingly increase or decrease. The push button 21 is located on a 
thick elastomer diaphragm/septum 24 that forms part of the surface of 
control unit 10. When the control unit 10 is implanted subcutaneously, the 
push button 21 can be pressed by manually applying pressure to the skin 
just above the implant. As the patient presses and holds down the 
actuation push button 21, sphincter fluid pressure is reduced, enabling 
the patient to urinate. As soon as hand pressure is removed, the patient 
immediately becomes continent. A bladder pressure sensing bulb 16 is 
implanted in the wall 32 of the bladder 26 and senses bladder fluid 
pressure by compressing slightly as bladder pressure increases. 
Alternatively, the bladder pressure sensing bulb 16' can be placed 
anywhere in the abdomen, specifically in the abdomen just below the 
bladder. When at this location, the bulb can sense abdominal pressure plus 
to some extent a pressure which is dependent on bladder volume. The 
bladder pressure sensor bulb 16 (alternatively, bladder pressure sensing 
bulb 16') is filled with an incompressible reference pressure fluid 28, 
and is hydraulically linked by line 18 (alternatively, line 18') to 
control unit 10. 
FIG. 3 is a more detailed top view of the improved control unit 10. The 
control unit has an upper shell 11 which is surrounded by an elastomer 
band 19 into which has been molded three suture holes 19a. The elastomer 
band 19 can be made from silicone rubber or other biocompatible 
elastomeric polymers. The purpose of the suture holes is to hold the 
implant in place immediately after surgery until fibrotic encapsulation 
occurs. The line 18 is connected to the sensor bulb 16 and the line 14 
connects to the inflatable cuff 12. An important purpose of the band 19 is 
to join the lines 14 and 18 with a silicone rubber to silicone rubber 
connection which is much more secure than a silicone rubber to metal 
connection. This connection is typically bonded with silicone type 
adhesives. (Note: Although this feature has been described in connection 
with the MAHS apparatus, it is to be understood that it can be used in any 
environment in which a silicone rubber line is connected to the port of a 
metallic casing. For instance, any implantable device may contain a 
silicone rubber line which connects to a port of a metallic casing. Also, 
although lines 14 and 18, and elastomer band 19 have been described using 
silicone rubber, other biocompatible polymers could be substituted for the 
silicone rubber and provide the same advantage.) 
FIG. 4 is a cross-sectional view of the actuator at 4--4 of FIG. 3. The 
elastomer diaphragm/septum 24 is centered within the upper shell 11. A 
push button 21 is held in place at the center of the diaphragm/septum 24 
by means of a screw 23 which holds in place a separator 25. When finger 
pressure is applied through the skin onto the push button 21, the 
diaphragm/septum 24 is deflected downward and the separator 25 applies a 
downward force onto the bellows cover 29 of the bellows 30 thus causing a 
compression of the bellows convolutions 31. The annulus 33 is welded along 
its inner edge to the lowest of the bellows convolutions 31 and at its 
outer edge it is welded to the top shell 11. When the push button 21 is 
deflected downward causing the bellows cover 29 to be deflected downward, 
the cuff chamber 40 increases in volume which causes fluid to be sucked 
into the bellows chamber 40 from the cuff 12. The path of the cuff fluid 
is through the connecting tube 14 through the interior lumen 42 of the 
cuff port 44 and finally entering the cuff chamber 40. As previously 
described, when the push button 21 is deflected downward, the cuff chamber 
40 fluid volume is increased resulting in fluid being withdrawn from the 
cuff 12 thus removing pressure from the patient's urethra and thereby 
allowing urination. When the pressure on the push button 21 is removed, 
the spring force of the convolutions 31 of the bellows 30 is such as to 
cause the cuff fluid to be pressurized at a predetermined adjustable 
minimum or nominal pressure which is set by the spring rate of the bellows 
30 and the volume of fluid that is put into the cuff chamber 40. 
Continence is typically maintained by applying a fluid pressure to the 
cuff 12 between 20 and 80 cm of H.sub.2 O. 
Fluid can be added or removed from the cuff chamber 40 by placing a 
(typically) non-coring needle of a hypodermic syringe through the skin, 
through the diaphragm/septum 24 and finally entering the antechamber 41 
which is in fluid communication with the cuff chamber 40 through the 
opening 43. A needle stop 11a prevents the hypodermic needle from applying 
force to the bellows cover 29 of the bellows 30 which force if applied 
could cause an error in the reading of the cuff chamber pressure. In this 
manner, the nominal pressure applied to the cuff 12 can be adjusted by the 
amount of fluid added to or removed from the cuff chamber 40. Once the 
cuff pressure adjustment has been made, the syringe with a (typically) 
non-coring hypodermic needle is pulled out of the diaphragm/septum 24 and 
out of the body. 
The sensor bulb 16 is connected to the sensor chamber 50 of the control 
unit 10 by means of the connecting tubing 18 which connects to the 
interior lumen 52 of the sensor port 54 and finally into the sensor 
chamber 50. When increased pressure is applied to the sensor bulb 16, the 
pressure in the sensor chamber 50 is increased and this pressure is 
immediately transmitted through the cover 29 of the bellows 30 and causes 
an immediate increase in the pressure in the cuff chamber 40 and within 
the cuff 12. By this means, any sudden increase in pressure in the 
abdominal region caused by running, jumping, or coughing will immediately 
cause a comparable increase in the pressure exerted on the urethra by the 
cuff 12 thereby eliminating the possibility of stress incontinence. The 
sensor chamber 50 is enclosed on its bottom side by the bottom cover 17 
which is welded along its periphery to the top cover 11. 
Typical materials for such a device are silicone rubber for the diaphragm 
septum 24 and the outer ring 19; CP titanium or a titanium alloy can be 
used for all the metallic parts including the bellows convolutions 31; 
normal saline solution is typically used as the working fluid for both 
cuff fluid and sensor fluid. Silicone rubber, or other biocompatible 
elastomeric polymers, would be used for making the tubing 14, the tubing 
18, the sensor bulb 16 and the urethral cuff 12. 
To remove fluid from the cuff chamber 40 when pushing down on the push 
button 21, it is necessary that the area of the diaphragm/septum 24 in 
contact with the antechamber 41 be very much less than the area of the 
bellows cover 29. This is because downward deflection of the push button 
21 causing downward deflection of the diaphragm/septum 24 results in 
increasing the pressure in the cuff chamber 40 while downward motion of 
the bellows cover 29 results in decreasing the pressure in the cuff 
chamber 40. Hence, to operate as intended, the area of the bellows cover 
29 must be considerably greater than the area of the diaphragm/septum 24 
that is in contact with the antechamber 41. 
Obviously many modifications and variations of the present invention are 
possible in light of the above teaching. It is therefore to be understood 
that within the scope of the appended claims the invention may be 
practiced otherwise than as specifically described.