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The invention relates to a tactile control device. More particularly, this
invention relates to a tactile control device which is used as a remote
sensing device for a fiberscope.
In many cases, it has been desirable to examine internal organs, passages
and the like of the human body for purposes of diagnosis, biopsy, and
polyp removal in preparation for surgery without cutting open the patient.
An examination of intestine prior to surgery can enable a surgeon to
better prepare for what he encounters at operation. The benefits of a
prior visual examination without surgery are obvious. One method of
examining the internal organs of the patient without major surgery is to
insert a remote sensing device such as a fibroptic endoscope into the body
through a natural body orifice or a specially prepared surgical opening.
The use of remote sensing devices for internal examination is not limited
to medicine. Remote sensing devices can be used to examine the interior of
otherwise inaccessible mechanical structures without opening them; such as
aircraft wings, the walls of buildings, the enclosed areas of any
structure. In these cases, an internal examination, without putting a
major opening in the structure, can help to determine the reason for
mechanical failure or the level of corrosion levels.
When using a remote sensing device, a common problem arising in medical or
mechanical applications is to be able to maneuver the inspection end of
the device around obstructions to the proximity of the area of interest.
In the past, this maneuvering has been by a trained operator who will see
the obstruction and then hazard a guess as how to direct the device safely
around the obstruction. Such a mode of operation without the benefit of
binocular depth perception is time consuming. Particularly undesirable in
medical observation, is that the prolonged presence of the remote sensing
device in the body and the frequent occurrence of excessive pressure of
contact on an internal organ can result in damage or perforation at sites
most often along the course of the instrument in no way related to the
visualized area. In more recent times, use has been made of fiberscopes
which allow viewing around bends. These fiberscopes are generally
constructed with an elongated flexible insertion tube having a distal end
in which an illuminating and viewing system is mounted and a proximal end
in which a control unit is mounted for controlling the bending of the tube
at the distal end. In many cases, the control unit employs four control
cables and two turning knobs to direct the distal end in any one of four
directions, i.e., up, down and side-to-side. The illuminating and viewing
system usually employs glass fiber optic devices to transmit light to the
distal end while allowing viewing of the surrounding environment at the
distal end. To this end, the control unit is usually connected to a source
of light and carries an eyepiece for viewing purposes.
Generally, when using a fiberscope of the above type, for example for
inspection of a colon, the distal end is inserted into a patient via the
rectum and is then guided through the colon. In order to direct the distal
end and the trailing flexible tube through the colon, the user views
through the eyepiece in the control unit. Should the colon turn, the user
manipulates the turning knobs of the control unit to bend the distal end
up, down, left or right so as to follow the bend of the colon.
However, since the colon follows a tortuous path, the walls of the colon
can fold over so as to define bends of 90.degree. or more. In cases where
a distal end of a fiberscope reaches such a bend, a "red out" condition is
presented. That is, the distal end abuts against the colon wall so that
the user cannot see the direction in which the colon is bent. As a result,
the user must then withdraw the tube inflate further with air or carbon
dioxide and experiment with the turning knobs to determine which direction
is the correct one to follow. In some cases, aggravated bendings of the
distal end of a fiberscope may tear or otherwise damage the colon wall. In
still other cases, use is made of expensive external equipment to
determine the direction in which the distal end should be directed.
Accordingly, it is an object of the invention to provide a remote sensing
device which can be relatively easily maneuvered around obstructions.
It is another object of the invention to provide a remote sensing device to
ease medical examination of internal organs through natural body orifices.
It is another object of the invention to determine that the pressure of the
instrument against the wall of an organ in no area exceeds the tensile
strength of that organ.
It is another object of the invention to provide a remote sensing device
for internal examination that will automatically provide data to detect
obstructions and provide information for avoiding the obstruction.
It is another object of the invention to provide a tactile control device
which can be incorporated into existing fiberscopes.
Briefly, the invention provides a tactile control device which comprises a
flexible hood, made for example of a flexible digital foam, for
circumferentially surrounding a distal end of a flexible tube of a
fiberscope and a plurality of pressure-sensitive sensing devices which are
mounted inside the hood for emitting a directional signal in response to
pressure from flexing of the hood. In addition, a plurality of contact
points can be located along the course of the fiberscope inside a
pressure-sensitive covering to prevent lateral torque of the colonoscope
from causing, for example, a lateral rupture of the wall of a bowel.
The tactile control device is particularly adapted to function with a
fiberscope. For example, the tactile control device may be used with a
fiberscope including an elongated flexible insertion tube, an illuminating
and viewing system mounted at a distal end of the tube and a control unit
for bending the tube at the distal end in two planes. In this case, the
flexible directional sending hood is mounted over the distal end so as to
circumferentially surround the illuminating and viewing system. In
addition, the hood is disposed to project forwardly of the distal end so
that the sensing devices are disposed circumferentially forward of the
distal end. Upon an inward flexing of the hood, the sensing devices are
able to emit a signal indicative of the location of the flexed section of
the hood. These signals, in turn, can be used to activate the control unit
of the fiberscope in order to direct the distal end in a direction away
from the area of greatest pressure.
The sensing units consist of inside contact points with wires running along
the instrument inside the pressure sensitive covering, for example a
digital foam layer, to an ohmmeter warning system located proximally. The
warning system, in turn, has a resistance measuring device, such as an
ohmmeter, connected to the contact points to receive the signal and
translate the signal into a pressure signal via an ohmmeter measurement.
The contact points beneath the flexible hood in the distal portion are
directionally oriented to provide the operator with information as to the
location of the lumen.
In another embodiment, each sensing device includes a pair of electrically
conductive plates, such as piezoelectric crystals, microspring sensors or
flexible conductive plastic sandwiches which are disposed in slightly
spaced relation to each other and a pair of contact wires. Each wire
extends from a respective contact plate so that, when pressure is applied
against the wall of the intestine, the plates contact each other and
complete an electrical circuit through the wires in order to emit a
signal.
In an automatic system, a control means is connected to each pair of wires
as well as to the control unit of the fiberscope in order to activate the
control unit in response to a received signal. This control is so
connected with the sensing devices as to activate the control unit of the
fiberscope to bend the distal end in a direction away from the sensing
device which causes the signal.
In addition, the tactile control device may employ a display board with
indicators to indicate the position of a flexed hood section, i.e. the
sensing device causing a signal relative to the remainder of the hood. In
this case, the indicators on the display board are suitably connected to
the control means or to the pairs of wires leading from the plates in the
hood.
When in use, for example, as in a colonscope, should the distal end of the
flexible hood of the tactile control device abut against the bend in a
colon, a sensing device will close and emit a responsive signal. The user
may then manually adjust the fiberscope via the control unit so as to move
the distal end away from the obstruction. Alternatively, the signal may be
processed automatically by the control means such that the control unit of
the fiberscope automatically responds to the signal to move the distal end
away from the obstruction. In this way, the distal end can be maintained
in a centered position within the colon passageway even if tortuous bends
are encountered in the colon passageway. In essence, the tactile control
device augments the illuminating and viewing system of the fiberscope by
providing a tactile sense to guide the colonscope through the colon.
The tactile control device may also have application in industry in
directing wires through conduits; in inspecting parts, for example in
airplane wings that require internal inspection; detecting openings within
walls; and the placement of electrical cables and telephone wires within
existing structures in which direct visualization is not possible.
The tactile control device may also be modified to enhance the use of a
fiberscope. For example, the control device may include a plurality of
pressure-sensitive flexible contacts or switches which can be disposed
along the entire length of a fiberscope. Such pressure sensitive covering
would respond to predetermined contact pressures thereon, for example the
pressures exerted by the wall of the colon. Thus, should the pressure
along any portion of the fiberscope exceed the tensile strength, e.g. of a
colon wall, the sensors would give a warning of this impending condition.
The pressure sensitive devices which are used both in the tactile control
device at the distal end of the fiberscope as well as along the length of
the fiberscope may be of the same type with those at the distal end being
set for greater sensitivity than those along the length of the fiberscope.
Further, any suitable type of pressure sensitive device may be used
including those with variable conductivity, such as Dynacon A, B, C or D
as described in "Computer Magazine", March 1978 issue, under the title
"Digital Foam".
These and other objects and advantages of the invention will become more
apparent from the following detailed description taken in conjunction with
the drawings in which:
FIG. 1 illustrates a schematic view of a tactile control device on the
distal end of a fiberscope in accordance with the invention;
FIG. 2 illustrates a view of the fiberscope of FIG. 1 with the tactile
control device removed;
FIG. 3 illustrates a schematic view of a system utilizing a tactile control
device according to the invention;
FIG. 4 illustrates a view of the tactile control device at a bend within a
colon;
FIG. 5 illustrates a partial cross-sectional view of flexible tube of a
fiberscope with pressure sensitive switches disposed along the length
thereof;
FIG. 6 illustrates a partial cross-sectional view of a fiberscope utilizing
another form of pressure sensitive switch; and
FIG. 7 illustrates an end view of a modified tactile control device for a
fiberscope in accordance with the invention.
Referring to FIG. 1, the directional tactile control device 10 is adapted
for mounting on the distal end 11 of a fiberscope 12, for example a
colonoscope. In this regard, the fiberscope can be made of any suitable
construction adapted for entry into other anatomical passages than the
colon. Such fiberscopes are of known construction and need not be
described in detail.
Alternatively, the fiberscope can be of a construction which can be
employed in industrial applications, such as to inspect lines in an
airplane wing.
Referring to FIG. 2, the fiberscope 12 includes an elongated flexible
insertion tube 13 which terminates at the distal end 11, an illuminating
and viewing system 14 mounted at the distal end 11 and a control unit 15
at the proximal end of the tube 13 for bending the tube 13 at the distal
end in two planes. For example, the control unit 15 employs two pairs of
cables (not shown) which extend to a bending section 16 of the tube 13 as
well as two knobs 17, 18 which function to control the cables so as to
affect movement of the bending section 16 in one of four directions,
namely up, down, and from side-to-side. The illuminating and viewing
system 14 employs a flexible optic fiber bundle 19 (FIG. 1) which extends
from the distal end 11 to the control unit 15. The control unit 15 can be
connected to a suitable illuminating means (not shown) which has a light
source for transmitting light through at least one of the optic fibers to
illuminate an object of interest at the distal end 11 of the tube 13. In
addition, a viewing means 20 such as an eye-piece or a camera (not shown)
is mounted on the control unit 15 to permit viewing of the object of
interest via a lens 21 at the distal end 11.
Referring to FIG. 1, the fiberscope 12 has a flexible central shaft 22,
e.g. of Teflon which houses the fiber bundle 19 and lens 21. In addition,
the shaft 22 has a pair of passageways 23, 24 which serve for the usual
purposes, for example for inflating and suction procedures, for biopsy, or
other tissue collecting procedures.
The tube 13 of the fiberscope 12 is sized to be passed through a colon and
has sufficient flexibility so as to bend during passage through a colon
passageway. The flexible tube 13 has a circular cross-section and acts as
a conductor of visual and electrical information between the object under
examination and the operator. To this end, the bundle of optical fibers 19
transmit light to the distal end 11 in order to illuminate the object
under examination, while reflected light is passed through the lens 21 to
the eye-piece 20 for visual examination. Alternatively, or in addition, a
camera can be connected to the eyepiece in order to take still pictures or
motion pictures. Also, the image received at the eye-piece may be
transmitted to a television monitor or the like for viewing by others.
Referring to FIG. 1, the tactile control device 10 includes a flexible hood
25, e.g. of flexible digital foam, such as Dynacon, which
circumferentially surrounds the illuminating and viewing system 14 at the
distal end 11 of the fiberscope 12. As shown, the hood 25 projects
forwardly of the distal end 11, for example a distance of one centimeter,
and is made in the shape of a ball of flexible material, such as a clear
flexible ethlion. In addition, the tactile control device 10 includes a
plurality of sensing devices 26 which are disposed circumferentially on
the hood 25 forward of the distal end 11 to cover the inside surface of
the hood 25. Each sensing device 26 is responsive to an inward flexing of
a section of the hood 25 in order to emit a signal indicative of the
location of the flexed hood section. To this end, each sensing device 26
includes a pair of electrically conductive plates 27 which are disposed in
slightly spaced relation to each other, for example, at a distance of
three millimeters, and a pair of contact wires 28 which are connected to
the plates 27. These contact wires 28 extend from the plates 27 to a
suitable control means 29 (FIG. 3). As shown, the contact plates 27 are of
elongated construction and are formed, for example of piezoelectric
crystals or microspring sensors. The spacing apart of the plates 27 and
the flexibility of the hood 25 are such that the plates 27 of a sensing
means 26 contact each other upon inward flexing of the hood 25 when the
hood abuts against the wall of a colon (FIG. 4).
Generally, the contact plates 27 are disposed along the outer edges of the
hood 25 since this edge generally forms the impact points for the end of
the fiberscope 12.
Referring to FIG. 3, the control means 29 is suitably connected to the
control unit 15, and particularly to the control knob 17, 18 to actuate
the control unit 15 in response to a received signal from the tactile
control device 10 in order to direct the distal end 11 of the fiberscope
12 in a direction opposite to the flexed hood section. The control means
has a second circuit as well as a motorized component in this circuit for
actuating the control knobs 17, 18.
The contact wires 28 and the control means 29 may also be connected to a
display board 30 having indicators 21 such as lights to indicate the
position of a flexed hood section relative to the remainder of the hood
25. Thus, the operator may bend the distal end 11 of the fiberscope 12 in
accordance with the information received from the display board 30 or the
distal end 11 may be automatically bent via the control means 29.
Referring to FIG. 4, the control wires 28 of the tactile control device may
extend along the outside of the central flexible shaft 22 of the
fiberscope 12 and be covered over by a sheath 36 which usually surrounds
the tube 13 of the fiberscope. Such a protective sheath 36 is sufficient
to protect the fiberscope 12 from the fluids and the like found in the
colon. The sheath 36 should also be made of a material which is suitable
for use in the colon.
Referring to FIG. 4, when in use, the fiberscope 12 is inserted into the
colon 33 and travels along the passageway 34 formed by the colon 33.
During this time, the operator can view the interior of the colon 33 via
the viewing and illuminating system 14 (FIG. 1). Should a section of the
hood 25 contact the wall of the colon 33, the contact pressure flexes the
hood section inwardly. This, in turn, causes the contact plates 27 thereat
to come into contact and complete the circuit along the associated wires
28. A suitable signal is then emitted to the control board 30 to indicate
the area of pressure. This is represented by the appropriate panel
indicator 31. Thus, the direction of the pressure point of maximum impact
on an obstruction is indicated. In addition, the signal also activates the
control means 29 such that the motorized component of the control means 29
is activated to turn the appropriate knob or knobs 17, 18 of the control
unit 15 in the direction required to move the distal end 11 and thus, the
hood 25, away from the point of pressure.
With the tactile control device 10 in operation, the fiberscope 12 will
automatically seek the most central position within the colon 33 or within
the lumen of an intestine or any other tedious structure. This facilitates
passage and prevents impedance of the fiberscope.
It is to be noted that visual inspection of an internal organ occurs
through the optic fiber bundle 19 in known manner. For example, a light
source (not shown) projects light via a suitable means in the control unit
15 into and through some of the optic fibers to illuminate the object of
interest. The lens 21 at the distal end 11 collects the reflected light
from the object and transmits the reflected image through the remaining
optic fibers to the eye-piece 20 or a viewing screen for visual
examination by an operator.
Referring to FIG. 4, the tactile control device 10 may also include a
plurality of pressure-sensitive contacts 35 which are disposed along the
insertion tube 13 beneath a layer or sheath 36 of Dynacon or other
suitable material with variable conductivity. These contacts 35 beneath
the outer sheath 36 form a network of sensors which are able to emit
warning signals when a given pressure is exceeded; thus warning the
operator of impending disruption of the bowel by any portion of the
instrument. As indicated, the contacts 35 may be disposed under the sheath
36 to generate signals to indicate that the sheath 36 is in contact with a
bend in the colon passageway 34 with sufficient pressure that the tensile
strength of the colon wall is in danger of being exceeded. Thus, excess
pressure registered e.g. by an ohmmeter from contact 35 will signal the
operator to cease the application of pressure to the colonoscope until the
tube 13 can be reoriented to reduce the pressure against the colon wall.
In this regard, the generated signal can be emitted via a suitable
electrical circuit to the control board 30 to sound an audible warning
signal and/or to give a visual warning signal.
Referring to FIG. 5, instead of using a flexible sheath with multiple
contacts as the pressure sensitive devices, a series of pressure-sensitive
microswitches 37 can be spaced along the tube 13 of a fiberscope under the
flexible outer sheath 32. As shown, each microswitch 37 is of a suitable
known construction, e.g. employing a movable button 38 which can be
depressed into a housing 39 to close the switch and complete a circuit.
For this purpose, a flexible plate 40 is positioned above each microswitch
37 to close the circuit should the tube 13 be subjected to undue pressure
at the location. Each microswitch 37 is also connected to a positive wire
41 to emit a signal to the control board (not shown) as above, to inform
the operator of an excess pressure condition at the location of the
activated microswitch.
It is noted that the microswitches 37 are mounted not only along the tube
13 but also circumferentially about the tube 13. Further, the plates 40
are arranged to press radially inwardly relative to the tube axis.
Referring to FIG. 6, the pressure sensitive devices may also be in the form
of micro dip switches 42 disposed at intervals along the tube 13.
Referring to FIG. 7, wherein like reference characters indicate like parts
as above, the sensing devices 26 may also be in the form of microswitches
as in FIGS. 5 and 6 rather than in the form illustrated in FIG. 1.
Further, when used with pressure sensitive devices along the length of the
tube of a fiberscope, the microswitches at the distal end are more
sensitive than the sets of proximal switches. Thus, the distal
microswitches are used for sensitive tip control while the other switches
are used to prevent disruption of a structure, such as a colon.
This invention thus provides a tactile control device which can be easily
incorporated into existing fiberscopes, particularly colonoscopes. In
essence, the invention provides a remote sensing device which can be used
to sense obstructions and to indicate such. An operator can the note the
obstruction and visually adjust the fiberscope to avoid the obstruction or
the control device may be interconnected with a system which automatically
corrects the position of the distal end of a fiberscope to avoid a sensed
obstruction and maneuvers the instrument to the center of a lumen by
seeking the point of least resistance. Still further, the invention
provides a tactile control device which can be used industrially to
visually inspect objects which are relatively inaccessible.
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