Apparatus and method for stimulating penile erectile tissue

A stimulator for penile erection comprises a body member which may be inserted into the rectum of a user, the body member being so shaped as to closely conform to the topological configuration of the rectum from the anal area to a site adjacent to the prostate gland. Within the body member is electrical circuitry for generating a neurally stimulating electrical signal. Electrodes, placed at particular locations on the surface of the body member, apply the signal to the user. At least one of the electrodes closely contacts the prostate gland when the body member is operatively disposed, at a region or spot on the prostate gland previously determined to be sensitive to electrical stimulation. Also disclosed is a method for making the aforesaid body member by taking an impression of the rectum of the user, and a method for inducing penile erection which includes the steps of locating sensitive regions or spots on the prostate gland, and applying electrical stimulation directly to those spots so as to induce erection.

BACKGROUND OF THE INVENTION 
This invention relates to apparatus and a method for applying electrical 
energy to living tissue, and more particularly, to apparatus and a method 
for stimulating penile erectile tissue and a method of making such 
apparatus. 
As is well known, the erectile tissue of the penis is composed of hollow 
sinuses, the walls of which contain involuntary muscle tissue. Blood 
reaches the sinuses through arterioles and capillaries, and the outlets 
from the sinuses are also controlled by involuntary muscle. In erection, 
impulses from the pelvic nerve cause dilation of the arterioles and 
constriction of the involuntary muscle controlling the outlets from the 
sinuses. The combined effect of these actions is to dilate the vascular 
spaces and to create high pressure within them, causing hardening and 
erection of the organ. 
Normal erection is dependent upon a complex interaction of psychological, 
neurological and vascular factors. Failure of any of them can result in an 
inability to sustain erection, a condition commonly referred to as male 
impotence. 
It has been suggested that, in the case of individuals whose impotence is a 
result of certain neurological deficits, the application of external 
electrical stimulus may ameliorate the impotence. Thus, for example, in 
U.S. Pat. No. 3,403,684, issued Oct. 1, 1968, to Stiebel, et al., a device 
was suggested in which a pair of electrodes were placed in the area of the 
prostate gland of a user, and it was proposed that an electrical signal be 
applied to the electrodes to cause electrical stimulation of the 
surrounding tissues. 
It has now been demonstated in laboratory animals that stimulation can best 
be accomplished by applying an electrical stimulus as directly as possible 
to certain highly sensitive and identifiable areas of the prostate gland. 
It is believed that if the signal is applied to these areas, the precise 
locations of which will vary from individual to individual, the nature of 
the signal is less critical than was formerly thought, and the desired 
results can be consistently and reliably obtained. 
It is, therefore, a general object of this invention to provide apparatus 
and a method for stimulating erectile tissue, and more particularly 
apparatus and a method which are useful to promote penile erection by 
electrical stimulation. 
Another object of this invention is to provide a method of making apparatus 
for stimulating penile erection, and it is still another object of the 
invention to provide a genital stimulator which is compact, 
self-contained, and capable of being accurately placed and positioned for 
use. 
Another object of this invention is to provide a genital stimulator which 
is maintained in position for use by the anatomical structures, 
particularly the musculature, which surround it when it is positioned for 
use. 
Other objects will appear hereinafter. 
The foregoing and other objects are realized, in a presently preferred form 
of the apparatus, by a stimulator which comprises a body member, the shape 
of which is determined by an impression molded in situ, and which is 
adapted for insertion into the rectum of a user. Molding in the above 
manner ensures that the body member is so configured as to closely conform 
to the unique configuration of the rectum of each user. Within the body 
member there is placed a highly miniaturized electrical signal generator, 
and electrodes are disposed at carefully selected localities on the outer 
surface of the body member. In accordance with the present invention, at 
least one electrode is juxtaposed as closely as possible to a selected 
spot on the prostate of the user which has been determined to be sensitive 
to electrical stimulation. Close conformity of the body member to the 
configuration of the rectum of the user, as well as a unique homeostatic 
effect described below, maintains the electrode in close proximity to the 
sensitive spot, and assures application of electrical impulses to that 
spot to stimulate erection. Electrical signals are generated by signal 
generating circuitry disposed within a cavity in the body member, and the 
body member, signal generating circuitry and its associated power supply 
are self-contained. Actuation of the apparatus may be by means of a 
manually operated or magnetically activated switch associated with the 
body member, or by remote telemetric means. 
In its method aspect, the present invention involves palpation of the 
prostate gland of a potential user and application to the prostate, at 
selected spots, of an electrical impulse. The result of the application of 
the impulse at the selected spot can be sensed or observed, and determines 
for the clinician the efficacy of application of electrical stimulus to 
that spot. When the sensitive spot or spots of the prostate have been 
identified, an impression is taken of the rectum of the user in at least 
the region extending from the anus to a location proximate to the prostate 
gland, and from that impression, a body member closely conforming to the 
shape of the rectum can be made. Electrodes are positioned on the body 
member at locations corresponding to the previously identified sensitive 
spot or spots, and at other locations which provide suitable electrical 
contact with the tissues of the user. 
The method of making the apparatus involves the taking of an impression of 
the rectum of the potential user by inserting into the rectum a sheath; 
injecting a molding composition into the sheath; permitting the molding 
composition to become somewhat hard; withdrawing the sheath slightly and 
permitting the composition to further harden; and then removing the sheath 
and the impression when the composition has fully hardened. The hardened 
composition thus forms an impression closely conforming to the 
configuration of the rectum, from which the body member of the apparatus 
may be molded. Electrodes can then be applied to the body member in 
positions corresponding to the sensitive spots on the prostate as earlier 
determined by palpation and stimulation, and electrical circuitry may be 
placed within the body member to produce the above-described apparatus. 
There are seen in the drawings forms of the invention which are presently 
preferred (and which represent the best mode contemplated for carrying the 
invention into effect), but it should be understood that the invention is 
not limited to the precise arrangements and instrumentalities shown.

DETAILED DESCRIPTION 
Referring now to the drawings in detail, wherein like reference numerals 
indicate like elements, there is seen in FIGS. 1, 6 and 7, stimulator 
apparatus designated generally by the reference numeral 10. 
The apparatus 10 comprises a body member 12, adapted, as is best seen in 
FIG. 1, for insertion into the rectum 14 of a user. The shape of the body 
member 12 is unique to each user, and is arrived at by molding in situ, in 
a manner described in detail below. 
Disposed on the outer surface of the body member 12 are electrodes which 
are so positioned that when the body member 12 is properly disposed within 
the rectum 14 they intimately contact the mucosa of the rectum and 
adjacent structures. The electrodes comprise, in the illustrated 
embodiment, three ground electrodes, 16, 18 and 20, and what may be 
referred to conveniently as an active electrode 22. As is best seen in 
FIG. 1, the electrodes 16, 18 and 20 confront the anal sphincter 24 of the 
user. The active electrode 22 intimately contacts the rectal wall, in 
juxtaposition to and in close contact with a critical region of the 
prostate gland 26. 
Referring to FIG. 6, it will be seen that the body member 12 has an 
internal cavity 28, in which there is housed electrical and electronic 
components and circuitry designated generally by the reference numeral 30. 
In general, the electrical and electronic components include a highly 
miniaturized and self-contained signal generator with associated control 
circuitry, and a power supply 32, all associated with a compact printed 
circuit board 34. 
Referring now to FIGS. 6 and 7, the electrical and electronic components 28 
may include an off-on switch 36, to activate the apparatus 10. In one form 
of the apparatus 10, in which the switch 36 is manually operable, the 
switch 36 is disposed in an end wall 38 of the body member 12, and is 
accessible for manipulation when the apparatus 10 is operatively disposed. 
As an alternative, the apparatus 10 may be activated by means of a radio 
frequency or other remote signal. FIG. 8 illustrates an alternative 
switching and latching circuit, which serves (as does the manual switch 
36) to activate the apparatus 10, placing the circuitry in an "on" 
condition and "latching" the circuitry 30 in that condition as long as 
desired. Referring again to FIGS. 6 and 7, the switch 36 may be encased 
within a flexible, liquid impervious end seal 38, sufficiently thin to 
permit ready manipulation of the switch 36 by applying external pressure 
to the end seal 38. 
Referring now to FIGS. 2 through 5, a presently preferred technique or 
method by which the body member 12 may be molded is illustrated. Referring 
first to FIG. 2, a finger 40 of a clinician or technician is placed in a 
flexible chemically inert sheath 42. The sheath 42 for this purpose may be 
an ordinary condom. The finger 40, encased in the sheath 42 is inserted 
intra-anally to a depth of perhaps 10 cm., to a point at which the 
prostate 26 may be palpated. Molding composition 44, contained in a 
syringe 46 whose tip 48 projects into the sheath 42, may now be injected 
into the sheath 42, thus filling the sheath and causing the sheath 42 to 
expand within the rectum 14. The molding composition 44 injected into the 
sheath 42, it has been found, can be of the kind known as Alginate or its 
equivalent, commonly used to make dental impressions. Such a material is 
prepared from a powder and water mixture, and, depending upon temperature, 
becomes firm but not rigid in about three to five minutes. The molding 
composition 44, once inserted into the sheath 42 is allowed to become 
semi-rigid, and the sheath 42 is drawn rearwardly through the anus to a 
small extent so tha anal sphincter 24 tends to compress the rigidifying 
mass. has been found that, at this stage of the procedure, application of 
topical electrical stimulation to the area (on the order of about 3 v.) 
causes contraction the musculature of the anal area so as to create an 
accurate and detailed outline of the configuration of the rectum 14. The 
sheath 42 is next left in position and the molding composition 44 is 
permitted to harden to form a plug-like mass 50 which cioseiy conforms to 
the configuration of the subject's rectum and anus. 
Referring now to FIG. 4, the mass 50 may be used, in a conventional manner, 
to make a female mold 52, and from the female mold 52 may be made any 
number of duplicates of the mass 50. The duplicates may be made from 
plaster, dental stone, epoxy or vinyl molding compounds of numerous kinds 
as well as methyl methacrylate (acrylic). The mass 50 may be inserted into 
the rectum 14 and used to determine the position of the electrodes in a 
manner to be described below. 
Referring to FIG. 5, the female mold 52 may be used to mold the final form 
of the body member 12. In the molding of the body member 12, the cavity 54 
of the female mold 52 is partly filled by a core 56 suspended within the 
cavity 54. Material suitable for the body member 12 includes castable 
plastic polymeric materials, such as methylmethacrylate. This material, 
like other suitable materials, is chemically inert and usable in the body. 
The material of the female mold 52, it should be understood, is of 
rubber-like composition, which can be deformed to permit removal of the 
molded article from the cavity 54. As an alternative, the female mold 52 
may be a split mold, halves of which can be separated to free a sharply 
undercut molded article. Removal of the core 56 from the molded article 
yields a body of the kind shown in FIG. 6, which includes a cavity 26 
whose shape conforms to the core 56. 
The electrodes 16, 18, 20 and 22 may now be applied to the body member 12. 
The electrode 22 is so positioned on the body member 12 that when the body 
member 12 is properly placed within the rectum, the electrode 22 is 
juxtaposed to a previously-determined sensitive spot 58 of the prostate 
26, seen in FIG. 1. The electrodes 16, 18 and 20 are so positioned as to 
be juxtaposed to the ring defined by the anal sphincter 24, and are 
grasped by the anus. The body member 12 may be provided, when molded, with 
projections 60 (one of which is seen in FIG. 6) at locations corresponding 
to the locations of the electrodes 16, 18, 20 and 22. This may be 
accomplished by appropriately adding material to the mass 50 or removing 
it from the female mold 52. The electrodes themselves may advantageously 
be "dished" to conform to the projections 60, and to present a convex 
outer surface which enhances electrical contact with surrounding tissues. 
The electrodes 16, 18, 20 and 22 may be of platinum or other suitable 
conductive, inert, non-polarizing material affixed to the body member 12 
by suitable adhesives. 
An important aspect of the invention is the manner in which the body member 
12 with its associated electrodes is held in position by the configuration 
of the rectum. The above-described molding technique, which yields a body 
member 12 closely conforming to the shape of the rectum, causes the body 
member 12, when positioned within the rectum, to be constrained against 
either rotation or movement axially with respect to the anal orifice. 
Thus, the body member 12, and consequently the electrodes 16, 18, 20 and 
22 are maintained by the anal cleft and the shape of the rectum 14 in a 
desired orientation with respect to the prostate gland 26. The 
above-described steps of allowing the molding composition 44 to become 
semi-rigid and then drawing the sheath 42 through the anus to a small 
extent assure that the impression defined by the mass 54 encompasses 
regions within the rectum 14 and also regions external of the anus. 
Contact between the body member 12 and the irregularly configured 
surrounding structures tends to maintain the body member 12 in precisely 
the desired position. The body member 12 may also be made with a roughened 
surface, to minimize any tendency of the apparatus 10 to shift with 
respect to the surrounding structures. 
Identification of the spot or spots to be stimulated by the apparatus 10 is 
accomplished by applying to the prostate gland 26 electrical energy which 
simulates the erection-stimulating signal ultimately to be produced by the 
apparatus 10. Such applications, when made at sensitive spots, cause 
palpable or visible physical reactions which are signs of incipient 
erection. The presently preferred technique for locating sensitive spots 
is the use of glove-mounted electrodes of the kinds described in 
co-pending application, Ser. No. 452,319 filed Dec. 22, 1982, for "MEANS 
FOR APPLYING ELECTRICAL STIMULI TO LIVING TISSUE" (assigned to the 
assignee of the present application), and illustrated in FIG. 11 herein. 
It has been found in laboratory animals that the application of electrical 
stimuli to critical spots of the prostate yields the desired result, while 
other regions show relative insensitivity to the application of the 
stimulus. As has been explained, advantages of the present apparatus and 
method flow from the ability of the apparatus 10 to apply energy directly 
to only those specific regions which have been ascertained to provide the 
desired result. When desirable spots have been identified and noted, the 
desired locations of electrodes such as the electrode 22 on the body 
member 12 may be ascertained by measurement, so that when the apparatus 10 
is positioned for use, the active electrodes are proximal the efficacious 
spots on the user's prostate gland. As indicated above, the unique shape 
of the body member 12, cooperating with key anatomical landmarks, serves 
to maintain the apparatus 10 in precisely the desired orientation with 
respect to the rectum and prostate gland, so that the electrodes are 
maintained in close contact with the anatomical structures adjacent to 
which they are placed. In humans, the anatomical landmarks which maintain 
the apparatus 10 in position include the anal cleft, the configuration and 
angular orientation of the anal sphincter, and the position and 
configuration of the prostate gland itself. 
A unique characteristic of the apparatus 10, which has been observed in 
laboratory animals, is its tendency to induce in the anatomical structures 
surrounding it forces which tend to restore the apparatus 10 and its 
associated electrodes to their desired positions. In other words, it has 
been found that the apparatus 10 creates what may be characterized as a 
self-restorative or homeostatic force, by electromechanical feedback 
resulting from displacement of the apparatus 10. This effect, it is 
theorized, is due to the fact that transient lateral displacement of an 
electrode such as the electrode 22 results in the application of 
electrical energy to the tissues contacted by the displaced electrode. 
This, it has been found, results in contraction of localized myofibers in 
those specific areas, and such contractions, due to the shape of the body 
member 12 and the surrounding anatomy tend to urge the apparatus 10 and 
electrode 22 to their original and desired positions. This homeostatic 
mechanism aids the above-described interaction between the shape of the 
body member 12 and surrounding anatomical landmarks to maintain the 
apparatus 10 and the electrodes in their desired positions. 
FIG. 9 illustrates a presently preferred electronic circuit by which 
stimulating signals can be produced, although other specific circuitry may 
perform the same function. The illustrated circuitry includes an astable 
multivibrator, designated generally by the reference numeral 62; a 
monostable multivibrator, designated generally by the reference numeral 
64; NAND gating 66, the purpose of which will be described below; two 
inverters 68 and 70; and an emitter-follower 72 providing a "high" voltage 
(about 20 volts) output. 
The power supply 32 in the presently preferred form of the invention is 
provided by lithium batteries (seen in FIG. 6), maintained in series 
relationship by a shrink-fitted sleeve as is known in the art. In one form 
of the invention, the power supply 32 consists of two 3.0 volt batteries, 
producing six volts, and eight 3.0 volt batteries, providing 24 volts. 
The astable multivibrator 62 and monostable multivibrator 64, which 
comprise the first and second stages of the circuitry 30, provide pulses 
of approximately six volts, and of a desired pulse-width and frequency. 
Thus, in the illustrated circuitry 30, the output of the astable 
multivibrator 62 is a series of square pulses at an amplitude of six volts 
and a frequency of about 30 to 33 Hz, and the monostable multivibrator 64 
serves to shape the pulses to a presently preferred width of 500 
microseconds. 
The principal components of the illustrated astable and monostable 
multivibrators 62, 64 are commercially available highly miniaturized 
integrated circuits. Thus, with reference to the astable multivibrator 62, 
each of the integrated circuits (labeled "IC-1") are of a type sold by 
Amperex Electronics Corporation, a subsidiary of North American Phillips 
Corp., as so-called "leadless inverted devices" ("LIDS"). They are 
electronically equivalent, however, to standard sized integrated circuits. 
The integrated circuit 74, for example, in FIG. 9, and the other 
integrated circuits labeled "IC-1" are "LIDS" equivalent to CMOS No. 4011 
integrated circuits available from numerous manufacturers, including, 
among others, RCA, Texas Instrument Corp., National Semiconductor, and 
Solid State Scientific. All of the other components in the preferred form 
of the circuitry 30 are commercially available items. By way of 
illustration, the diode 76 in one operative form of the circuitry is an 
Amperex Electronic Corporation Part No. LDD-5. The NPN transistor 78 used 
in the inverter circuit 68 is an Amperex LDA-404 ("LIDS" equivalent to 2N 
3904). The PNP transistor 80 in the inverter 70 is an Amperex LDA-452, 
equivalent to a 2N 3906. The NPN transistor 82 is also an Amperex LDA-404. 
The circuitry 30 illustrated in FIG. 9, as presently contemplated, may use 
one of two modes of control. In the first mode, perhaps best seen in FIG. 
9, manual operation of the switch S.sub.1 (the above-mentioned switch 36, 
seen in FIGS. 6 and 7), applies to the astable multivibrator 62, 
monostable multivibrator 64, and other aspects of the circuitry 30, the 6 
volt supply. An output pulse will be repetitively supplied during the time 
in which the circuitry 30 is so powered. In other words, stimulation is 
enabled upon closing of the switch 36 to power the circuit, and 
stimulation is inhibited when the switch 36 is open. 
Referring now to FIG. 8, there is seen an alternative arrangement for 
enabling stimulation, using an external reed switch 84 to control pulse 
output, and hence stimulation. The reed switch 84 may advantageously be 
operated by an external magnet or other remotely operable means, under the 
control of the user. 
The reed switch 84 controls a flip-flop, designated generally by the 
reference numeral 86, which performs a latching function with respect to 
the power supply of the circuitry 30. The flip-flop 86 in its presently 
preferred form, is based upon a LIDS equivalent 4013 integrated circuit 
(LFF 4013), supplying, through the output resistor 88 a PNP transistor 90 
(LDA 452, LIDS equivalent to 2N3906). Because it is of the PNP type, the 
transistor 90 is "off" when it sees high Q, and when the transistor 90 is 
off no voltage will be seen at the six volt input of the circuitry 30. It 
will be appreciated, however, that changing the state of the flip-flop 86 
will turn on the six volt supply to the circuitry 30, thus enabling 
stimulation. 
The apparatus illustrated in FIG. 8 thus provides both a latching function 
(enabling continuous stimulation) and a controlled six volt power supply 
for the circuitry 30. The circuitry illustrated in FIG. 8 enables the 
stimulator apparatus 10 to be inserted into or removed from the rectum 14 
with assurance that the apparatus 10 is inhibited, thus eliminating 
undesirable effects such as untimely or unwanted neural stimulation 
affecting muscle groups other than those involved in penile erection. 
FIG. 10 illustrates diagrammatically the functional interrelationship 
between the reed switch 84, the flip-flop 86, the signal generating and 
control circuitry 62, 66, 68 and 72, and the power supply (represented in 
FIG. 10 by six volt and high voltage sources corresponding to the power 
supply 32). As can be seen in FIG. 10, closing of the reed switch 84 (by 
magnetic or remote means) configures the flip-flop 86 to provide to the 
other circuitry a controlled six volt supply. The other circuitry, in turn 
provides the stimulating signal and delivers it to the active electrode 
22. 
The above-described circuitry 30 is designed to drive an output load of 
approximately 330 ohms (the assumed load resistance based on observations 
in laboratory animals). When the output pulse is inhibited, the output is 
zero volts. When the output is enabled, the actual output level is a 
function of the voltage of the high voltage supply (V.sub.hv) In one 
operative embodiment, the high voltage supply provides twenty-four volts, 
and the output is within 0.5 volts of this voltage and substantially 
constant for 500 microseconds when driving a 330 ohm load. 
Those skilled in the art will appreciate that the high and low voltages, as 
well as the parameters (pulse width, frequency and wave form) of the 
output pulse may be varied by conventional circuit elements, perhaps 
controlled by telemetry. Utilizing appropriate feedback mechanisms, the 
circuit may be made self-regulating and self-optimizing. 
FIG. 11 illustrates, somewhat schematically, a surgical glove 92, to which 
there are affixed electrodes 94. The electrodes 94 may be electrically 
connected to a source 96 of electrical energy, such as a signal generating 
circuit analogous to the above-described circuitry 30. Palpation may thus 
be done using the glove 92, and stimulation may be accomplished by 
application of electrical energy through the electrodes 94. 
The present invention may be embodied in other specific forms without 
departing from its spirit and essential attributes and, accordingly, 
reference should be made to the appended claims rather than the foregoing 
specification as indicating the scope of the invention.