U.S. patent number 3,662,758 [Application Number 04/837,701] was granted by the patent office on 1972-05-16 for stimulator apparatus for muscular organs with external transmitter and implantable receiver.
This patent grant is currently assigned to Mentor Corporation. Invention is credited to Eugene G. Glover.
United States Patent |
3,662,758 |
Glover |
May 16, 1972 |
STIMULATOR APPARATUS FOR MUSCULAR ORGANS WITH EXTERNAL TRANSMITTER
AND IMPLANTABLE RECEIVER
Abstract
A unit adapted to be implanted in a human body including a power
supply for having power induced therein from a source external of
the body, electrodes adapted to be attached to a muscular organ,
such as a bladder or the like, capacitors and SCR's in circuit with
said electrodes and said power supply for normally storing
electrical energy and discharging said electrical energy through
the electrodes upon conduction of the SCR's, triggering circuitry
connected between the power supply and the SCR's for triggering the
SCR's when the power induced in the power supply is temporarily
interrupted and an FM transmitter connected to the power supply and
between a pair of spaced apart electrodes so as to transmit a
signal varying in frequency according to the resistance of the
material between the electrodes; and an external control unit
including means for inducing power into the internal power supply
and controllable to periodically and temporarily remove power to
control the energy supplied to the electrodes and an FM receiver
with indicating means attached to provide an indication as to the
operation of the muscular organ.
Inventors: |
Glover; Eugene G. (Minneapolis,
MN) |
Assignee: |
Mentor Corporation
(Minneapolis, MN)
|
Family
ID: |
25275177 |
Appl.
No.: |
04/837,701 |
Filed: |
June 30, 1969 |
Current U.S.
Class: |
607/40; 128/903;
607/61; 607/72; 607/60 |
Current CPC
Class: |
A61N
1/36007 (20130101); A61N 1/3787 (20130101); Y10S
128/903 (20130101) |
Current International
Class: |
A61N
1/36 (20060101); A61N 1/378 (20060101); A61N
1/372 (20060101); A61m 001/36 () |
Field of
Search: |
;128/2.6E,2.6R,2.1A,2.1B,2.1E,2.1P,2.1R,419P,419R,421,422,423 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
Young, et al.; "American Journal of Medical Electronics" Apr.-June,
1964, pp. 28-33.
|
Primary Examiner: Kamm; William E.
Claims
What is claimed is:
1. Stimulator apparatus for the external control of a muscular
organ comprising:
a. an external transmitter unit including
1. transmitting means for producing a substantially continuous wave
power signal,
2. modulating means connected to said transmitting means for
superimposing control signals on said power signal,
b. an implantable unit including
1. power means for inductively receiving said power signal from
said external transmitter unit and operable to produce both supply
potential and control signals therefrom,
2.
2. at least one electrode adapted to be affixed to the organ
desired to be externally controlled,
3. controllable energizing means connecting said power means to
said electrode and operable to provide energization of said
electrode to provide stimulation of said organ, and
4. control means connected to said power means and to said
energizing means for controlling the operation of said energizing
means in response to
control signals from said power means. 2. The stimulator apparatus
of claim 1 wherein said modulating means includes electrical means
for sequentially interrupting the induction of power into said
implantable unit by said transmitting means.
3. The stimulator apparatus of claim 1 wherein:
a, said implantable unit includes a plurality of said
electrodes;
b. said controllable energizing means includes a plurality of
parallel stimulator circuits each connected to a different pair of
said electrodes; and
c. said control means is connected to each of said plurality of
parallel stimulator circuits and includes means for selectively
controlling the operation thereof.
4. The stimulator apparatus of claim 3 wherein each of said
plurality of parallel stimulator circuits include an electrical
energy storage device in circuit with a silicon controlled
rectifier.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
In the body the operation of many muscular organs can become
impaired, through injury to other portions of the body, without
injury to the muscular organ itself. A typical example of this is
the urinary bladder, in humans and other mammals, which is
controlled by the brain through the spinal cord and a peripheral
system of sympathetic and parasympathetic nerves and ganglia
connected between the spinal cord and the bladder. A disturbance to
any one of these nerve systems, the portions of the brain or spinal
cord concerned with micturition or the peripheral system, will
usually result in impairment of the micturition reflex, such that
the patient is unable to empty his bladder properly, even though
the muscle tissue of the bladder itself is healthy. This condition
is referred to as the "neurogenic bladder," signifying that the
bladder is incapacitated because of damage to the nervous system.
When the operation of a muscular organ is impaired, through damage
to other parts of the body, some other control for that organ must
be incorporated into the system.
2. Description of the Prior Art
In the prior art many attempts have been made to solve this problem
electronically. One such prior art device includes an implantable
bladder stimulator with a battery power pack. Obviously this is
undesirable since the patient would have to undergo surgery each
time the batteries become low in electrical energy. In a similar
prior art device a tuned tank circuit having a capacitor attached
thereto with electrodes connected to the bladder so that the
capacitor receives energy from the tank circuit to stimulate the
electrodes, is implanted in the patient. This device is also
undesirable since experience shows that three electrodes are
necessary to produce adequate stimulation and emptying of the
bladder. Each of these electrodes requires a pulse of 50 volts at 1
amp. for 1 millisecond. This represents a peak pulse power of 50
watts for each electrode, or a total of 150 watts peak power if all
stimulus pulses are delivered simultaneously, as they must be in
the case of the tank circuit and capacitor. In the prior invention
no means of storing power is provided, so the power pulses
delivered to the electrodes must be received at the tank circuit.
The transmitter does not operate between stimulus pulses, but only
at the time of the pulse for the duration of the pulse. Therefore
the tank circuit receiver must receive 150 watts peak power. Since
the coupling between the outside transmitter and the receiver
located inside the body is very inefficient, the pulse power output
of the transmitter must be in excess of 1 kilowatt.
SUMMARY OF THE INVENTION
The present invention pertains to stimulator apparatus for the
external control of a muscular organ including an implantable unit
having at least one electrode adapted to be affixed to the organ
with controllable energizing means connected to the electrode for
energization thereof and power means for receiving induced power
and control signals from an external source connected to said
energizing means for supplying electrical power thereto with
control means connected to said power means for utilizing said
control signals to control the energizing means; and an external
unit having transmitting means for inducing power into the internal
power means and modulating means connected to said transmitting
means for supplying control signals thereto. Said external unit
further including indicating means adapted to receive signals from
said implantable unit for indicating the operation of the muscular
organ.
It is an object of the present invention to provide new and
improved stimulator apparatus for the external control of a
muscular organ.
It is a further object of the present invention to provide
stimulator apparatus including means for indicating the approximate
operation of the muscular organ, such as the fullness of a bladder,
etc.
These and other objects of this invention will become apparent to
those skilled in the art upon consideration of the accompanying
specification, claims and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring to the drawings, wherein like characters indicate like
parts throughout the figures:
FIG. 1 is a block diagram of the external unit; and
FIG. 2 is an electrical schematic diagram of the implantable
unit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, an external or control unit is illustrated in
block form. The control unit includes a remote transmitting or
induction coil 10 adapted to be positioned adjacent to any
desirable portion of a body, as will be described in detail
presently. The remote transmitting coil 10 is connected to the
output of a power oscillator circuit 11 by means of a cable having
at least two conductors and a length sufficient to allow movement
of the transmitting coil 10 to the desired area of a body. The
power oscillator circuit 11 may be any desired oscillator capable
of providing the required frequency and power output. In the
present embodiment the output power of the power oscillator circuit
11 is variable over a range of 0 to approximately 50 watts at a
frequency of approximately 350 kilocycles. It should be understood
that any desired frequency and power output which will perform the
desired functions can be utilized and the foregoing values are only
for exemplary purposes. Further, the oscillator circuit 11 is not
illustrated in schematic form since any oscillator circuit which
can perform the desired functions may be utilized.
In the present embodiment the control unit is adapted to receive
power from a 110-volt AC source, represented by terminal 12. The
110 volts AC are supplied to an isolation transformer and rectifier
13, which supplies the required quantity of DC power to the
remainder of the circuitry. A power output regulator 14 is
connected to the isolation transformer and rectifier 13 and
regulates the amount of power supplied to the oscillator circuit 11
and, thus, the amount of output power from the oscillator circuit
11. An oscillator enable circuit 15 is illustrated between the
power output regulator 14 and the oscillator circuit 11. The enable
circuit 15 includes a monostable multivibrator or the like the
operation of which is controlled by a trigger circuit 16, which
includes a free-running multivibrator or the like. The trigger
circuit 16 provides periodic and/or sequential signals to the
enable circuit 15, which signals cause the enable circuit 15 to
periodically and/or sequentially change states. When the enable
circuit 15 is in the normal state the power oscillator circuit 11
is supplying power to the remote transmitting coil 10. When the
enable circuit 15 switches states, the power oscillator circuit 11
is turned off until the enable circuit 15 returns to its original
state. No specific circuitry is illustrated for the enable circuit
15 and trigger circuit 16 since the exemplary circuits described
are well known to those skilled in the art and any circuit which
will perform the desired functions may be utilized.
In the present embodiment, the free-running multivibrator of the
trigger circuit 16 is constructed so that it is unsymmetrical and
one side remains conducting for 5 milliseconds while the other side
is adjustable to provide a variable output repetition rate in the
range of approximately 0 to 50 completed cycles per second. The
monostable multivibrator of the enable circuit 15 receives signals
or pulses from each side of the free-running multivibrator in the
trigger circuit 16 and provides an output pulse approximately
one-tenth to two-tenths milliseconds in duration each time a signal
or pulse is applied thereto from the trigger circuit 16. Thus, the
enable circuit 15 supplies a first pulse to the power oscillator
circuit 11 when the trigger circuit 16 switches and 5 milliseconds
later, when the trigger circuit 16 switches states, the enable
circuit 15 supplies a second pulse to the power oscillator circuit
11. The trigger circuit 16 remains in the second state for the
period of time to which it is adjusted and the enable circuit 15
remains in its normal state. After the predetermined period of time
has passed the trigger circuit 16 again switches states for 5
milliseconds and the enable circuit provides two output pulses
approximately 5 milliseconds apart. The power oscillator circuit 11
is deenergized or shut off for the duration of the output pulses
from the enable circuit 15. Thus, the enable circuit 15 and trigger
circuit 16 in essence modulate the output of the power oscillator
circuit 11 or superimpose control signals on the output
thereof.
Also included in the control unit is an FM (frequency modulated)
receiver 20, including detector and demodulator, having an input
affixed to a receiving antenna 21, which antenna 21 may be remotely
positionable so that it can be placed adjacent various portions of
a body. An indicator or calibrated meter readout 22 is attached to
the output of the FM receiver 20 so as to provide an indication of
changes in frequency of the output. The indicator 22, for example,
may be calibrated in terms of material contained in a bladder
ranging from empty to full. Various other types of receivers and
indicators might be utilized wherein a variable characteristic
other than frequency is utilized to provide an indicator of the
operation of the muscular organ being controlled, but the present
system is utilized because it is believed to be the most accurate
under various changing conditions, such as variation in electrical
power, variations in muscular material being operated upon,
variations in distances between transmitters and receivers,
etc.
FIG. 2 illustrates an implantable unit which cooperates with the
control unit of FIG. 1 to provide complete stimulator apparatus.
The implantable unit includes power means generally designated 30,
controllable energizing means generally designated 31, control
means generally designated 32, transmitting means generally
designated 33 and a regulated power supply for the control means 32
and transmitting means 33, generally designated 34. The power means
30 includes a tank circuit 40 tuned to the frequency of the power
oscillator circuit 11 in the control unit. Since the entire
circuitry illustrated in FIG. 2 is implantable, generally within
the body of a human or other animal, it is inaccessible from the
exterior and power is induced into the tank circuit 40 by the
transmitting coil 10. The electrical power from the tank circuit 40
is rectified, filtered and at least partially regulated to provide
DC power at the line 41.
As previously described in conjunction with FIG. 1, the amplitude
of the DC power on the line 41 is externally variable through the
output regulator 14. The DC power on the line 41 is connected to
the controllable energizing means 31 and to the regulated power
supply 34. It should be noted that the filtering in the power means
30 is such that control signals superimposed on the energy induced
into the tank circuit 40 appear at the line 41. Further, the
regulated power supply 34 has sufficient regulation so that control
signals superimposed on the DC power at the line 41 have
substantially no effect on the output thereof. Thus, with regard to
effect on the remainder of the circuitry, control signals and DC
voltage are available on line 41 while only a regulated DC voltage
is applied to the control means 32 and transmitting means 33 from
the regulated power supply 34. The line 41 having control signals
thereon is also connected to an input 42 of the control means
32.
The controllable energizing means 31 includes a plurality of
stimulator circuits 45a, 45b, 45c, etc., each of which includes a
pair of electrodes 46a, 46b, 46c, a storage capacitor 47a, 47b,
47c, and an SCR (silicon controlled rectifier) 48a, 48b, 48c,
respectively. The pair of electrodes 46a and the storage capacitor
47a are connected to the line 41 across the output of the power
means 30 so that the storage capacitor 47a is normally charged to
the output voltage thereof. The SCR 48a is connected in circuit
with the pair of electrodes 46a and storage capacitor 47a so that
conduction of the SCR 48a provides a discharge path for the storage
capacitor 47a through the pair of electrodes 46a. A plurality of
stimulator circuits 45a-45c are utilized to increase the chances
that at least one of the stimulator circuits 45a-45c will remain
operable in the event of component failures, etc. The electrodes
46a are adapted to be affixed to the muscular organ it is desired
to control, such as a bladder or the like, and discharge of the
storage capacitor 47 through the electrodes 46 stimulates the
muscular tissue causing operation or contraction thereof. In
general the amplitude of the power output from the power means 30
is adjusted, through the output regulator 14, so that the voltage
supplied to the electrodes 46a, 46b, 46c, etc., is sufficient to
provide the desired results without causing adverse effects.
The control means 32 includes a monostable multivibrator 50 and a
4-bit shift register 51. While many or all of the circuits in the
implantable unit may be provided in integrated form, the 4 -bit
shift register 51 is the only one so illustrated, since this is the
most common form for commercially purchased shift registers at the
present time and since illustrating all of the circuitry contained
therein would lend nothing to this explanation. The 4 -bit shift
register is connected so that pulses from the monostable
multivibrator 50 are received therein to provide serial readout or
commutated signals, at the four outputs thereof, with the first
three outputs being utilized to trigger the SCR's 48a, 48b and 48c,
and the fourth output being applied to reset the shift register 51
and prepare it for the next series of input pulses. It should be
understood that many circuits might be utilized to sequentially
apply triggering signals to the various stimulator circuits 45a,
45b and 45c, and the 4 -bit shift register 51 is utilized because
of its simplicity, size and relatively small expense.
The monostable multivibrator 50 is constructed so that it provides
an output pulse having a duration of approximately 7 milliseconds
upon actuation thereof. As previously described, the line 41 has a
DC voltage prevalent thereon with control signals, consisting of
negative-going pulses or periods during which there is an absence
of DC voltage, of a duration between one-tenth and two-tenths of a
millisecond. These control signals appear in pairs approximately 5
milliseconds apart, with each pair being separated by some
predetermined or adjustable time. Since the control signals are
only 5 milliseconds apart and the first control signal changes the
state of the monostable multivibrator 50, for a duration of 7
milliseconds, the second control signal on the line 41 has no
effect on the monostable multivibrator 50. Thus, the first control
signal in a pair of control signals appearing on the line 41 causes
the monostable multivibrator 50 to produce a pulse which, through
the shift register 51, triggers one of the SCR's 48a, 48b or 48c.
Once the SCR 48a, 48b or 48c is triggered it continues to conduct
even after the triggering pulse is removed therefrom. Five
milliseconds after the first control signal appears on the line 41,
causing one of the SCR's 48a, 48b or 48c, to be triggered, a second
control signal appears on the line 41 and temporarily removes the
DC voltage from across the conducting SCR 48a, 48b or 48c, thereby,
terminating the conduction. At some predetermined time later a
second pair of control signals appear on the line 41 and the next
SCR 48a, 48b or 48c is triggered into temporary operation. Thus, as
long as the trigger circuit 16 is energized to provide control
signals in the implantable unit, the controllable energizing means
31 is energized to stimulate the muscular organ to which the
electrodes 46a, 46b and 46c are attached.
The transmitting means 33 includes a free-running multivibrator 52
and an amplifier-transmitter 55. The output of the free-running
multivibrator 52 is connected directly to one of the pairs of
electrodes 46b by means of a lead 53 and the input of the
amplifier-transmitter 55 is connected directly to one of the pairs
of electrodes 46c through a lead 54. The signal from the
free-running multivibrator 52 applied to the muscular organ between
the electrodes 46b and 46c is a low-level signal (in this
embodiment approximately 400 to 500 millivolts) so that it has no
adverse effect on the organ. When the electrodes 46b and 46c are
properly attached to a muscular organ, the output signal from the
free-running multivibrator 52 is amplified and utilized to modulate
the output of the transmitter in the amplifier-transmitter 55. The
impedance of the material between the electrodes 46b and 46c
dictates the amount of the signal from the free-running
multivibrator 52 which will reach the amplifier-transmitter 55.
Thus, the output frequency of the amplifier-transmitter 55 is
representative of the impedance of the material between the
electrodes 46b and 46c. In a bladder for example, typically the
impedance thereacross is approximately 400 ohms when the bladder is
full, or the muscle is stretched, and approximately 100 ohms when
the bladder is empty, or the muscle is relaxed. The variations in
frequency of the amplifier-transmitter 55 output are, therefore, a
direct indication as to the operation of a muscular organ, such as
the content of a bladder. The meter readout or indicator 22 can
thus be calibrated directly in the particular operation or
indication it is desired to monitor, such as bladder content.
Thus, stimulator apparatus for the external control of a muscular
organ is disclosed wherein an implantable unit, which can be
produced in an extremely miniature size through integrated circuits
and the like, is affixed to an internal muscular organ in the
bodies of humans, mammals, other animals, etc., and all signals,
including control signals and power, are induced therein from an
external control unit. The stimulator apparatus provides means for
the storage of power in the internal or implantable unit, enabling
the external transmitter to operate a greater period of time,
approximately 97 percent of the time as opposed to only 28 percent
of the time in prior art devices. This enables the peak power of
the transmitter to be reduced, generally by a factor of 50, and the
power handling requirements of the internal receiver section may be
reduced in like manner. The operation of the internal muscular
organ is monitored by inducing power into the implantable unit and
receiving signals from the internal transmitter. Further, control
signals are superimposed upon the induced power signals to cause
the implanted unit to stimulate the muscular organ and cause
operation thereof. While specific times and frequencies have been
set forth in the description of the preferred embodiment, it should
be understood that these times and frequencies can be varied
according to the needs of the particular function being performed
or the particular patient being acted upon. Further, some specific
circuits are disclosed to facilitate the explanation of the
operation and, it should be understood, that these circuits are
only exemplary and many other embodiments might be devised by those
skilled in the art to perform the functions set forth.
* * * * *