U.S. patent application number 09/835950 was filed with the patent office on 2001-08-09 for instrument for compensating for hand tremor during the manipulation of fine structures.
Invention is credited to Peer, Ferdinand.
Application Number | 20010012932 09/835950 |
Document ID | / |
Family ID | 7816969 |
Filed Date | 2001-08-09 |
United States Patent
Application |
20010012932 |
Kind Code |
A1 |
Peer, Ferdinand |
August 9, 2001 |
Instrument for compensating for hand tremor during the manipulation
of fine structures
Abstract
The invention relates to an instrument for the manipulation of
fine structures, said instrument detecting hand tremor and
compensating for this hand tremor by effecting counter-movements of
the working tip. The main area of application will probably lie in
the field of microsurgery, since the operations performed in said
field can be made difficult by the hand tremor of the operating
surgeon. Here, the tremor is detected by movement sensors, by
repeated analysis of the position of the handheld part (1) of the
instrument, or by deriving electromyographic signals from the
forearm of the operator. Intentional and unintentional movements
are differentiated from one another on the basis of one or more
criteria, such as movement amplitude, speed, frequency and
direction. To compensate for undesired movements, signals are sent
to an arrangement of actuators (3) which cause deflections of the
movable part (4) of the instrument, which deflections at the tip of
the instrument compensate for the hand tremor. When the instrument
is used as a needle holder in surgery, the actuators (3) can also
be controlled by push button in such a way that, by oscillations,
they facilitate the penetration of the suture needle into the area
being worked on.
Inventors: |
Peer, Ferdinand; (Hamburg,
DE) |
Correspondence
Address: |
Michael A. Goodwin, Esq.
Klaas, Law, O'Meara & Malkin, P.C.
Suite 2225
1999 Broadway
Denver
CO
80202
US
|
Family ID: |
7816969 |
Appl. No.: |
09/835950 |
Filed: |
April 16, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09835950 |
Apr 16, 2001 |
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09142426 |
Dec 28, 1998 |
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6238384 |
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Current U.S.
Class: |
606/1 |
Current CPC
Class: |
B25B 7/12 20130101; A61B
34/75 20160201; A61B 17/062 20130101; B25F 5/00 20130101; B25J
19/00 20130101; A61B 34/70 20160201; B25B 9/00 20130101 |
Class at
Publication: |
606/1 |
International
Class: |
A61B 017/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 8, 1997 |
DE |
19700402.4 |
Jan 7, 1998 |
DE |
PCT/DE98/00043 |
Claims
1. Instrument for the manual working of fine structures, consisting
of (a) a handheld section (1), (b) a section (4) which is movable
in relation to the handheld section (1), (c) actuators (3), and
where (d) the actuators (3) are designed to effect relative
movements between the handheld section (1) and the movable section
(4), which relative movements compensate at least partially for
movements of the handheld section (1).
2. Instrument according to claim 1, characterized in that one or
more sensors (2) are arranged on the handheld section (1), said
sensors (2) detecting the movement of the handheld section (1), and
their output signal being used to trigger the actuators (3).
3. Instrument according to claim 1 or 2, characterized in that one
or more sensors are arranged on the movable section (4), said
sensors detecting the movement of the movable section (4), and
their output signal being used to trigger the actuators (3).
4. Instrument according to one of claims 1 through 3, characterized
in that one or more sensors are arranged on the handheld section
(1) or on the movable section (4) or between the handheld section
(1) and the movable section (4), said sensors detecting the
relative movement between the handheld section (1) and the movable
section (4), and their output signal being used to trigger the
actuators (3).
5. Instrument according to one of claims 2 through 4, characterized
in that at least one sensor detects the acceleration.
6. Instrument according to one of claims 1 through 5, characterized
in that one or more sensors are provided for repetitive or
continuous detection of the position of the handheld section (1) in
one, two or three dimensions.
7. Instrument according to one of claims 1 through 6, characterized
in that one or more sensors are provided for repetitive or
continuous detection of the position of the movable section (4) in
one, two or three dimensions.
8. Instrument according to claim 6 or 7, characterized in that the
position of the instrument is detected optically via the ray path
of an operating microscope.
9. Instrument according to one of claims 1 through 8, characterized
in that a control or regulating unit triggers the actuators on the
basis of the data from the sensors for position detection and/or
movement detection.
10. Instrument according to one of claims 1 through 9,
characterized in that a control or regulating unit triggers the
actuators on the basis of a repetitive or continuous position
detection.
11. Instrument according to one of claims 1 through 10,
characterized in that electromyographically detected potentials are
used to trigger the actuators.
12. Instrument according to one of claims 1 through 11,
characterized in that when movements of the handheld section or
movable section occur, the compensation movements take place in a
predetermined or adjustable or automatically adapting frequency
range.
13. Instrument according to one of claims 1 through 12,
characterized in that when movements of the handheld section or
movable section occur, the compensation movements take place in a
predetermined or adjustable or automatically adapting amplitude
range.
14. Instrument according to one of claims 1 through 13,
characterized in that the actuators (3) can be triggered in such a
way that a rigid connection is obtained between the handheld
section (1) and the movable section (4).
15. Instrument according to one of claims 1 through 14,
characterized in that the actuators (3) can be triggered in such a
way that they can generate oscillations of the movable section (4).
Description
DESCRIPTION
[0001] Manual work on fine structures is made much more difficult
by the contraction of antagonistic muscles occurring involuntarily,
and in largely rhythmic succession, and referred to as tremor. This
is noticeable particularly in microsurgery when suturing fine
nerves or vessels, prolongs the duration of the operation and
reduces the quality of the result.
[0002] However, in order to be able to perform filigree work, use
is made, for example, of supports for the hands, or
micromanipulators, which convert relatively rough movements into
fine deflections.
[0003] The object of the invention is to make available a handheld
instrument for the manual manipulation of fine structures, in which
undesired movements, for example tremor, have no effect, or at
least less effect, on the manipulation.
[0004] The invention is based on the concept of evaluating the
undesired movements of handheld instruments and of deflecting, by
means of actuators, the working tip of the instrument (in surgical
applications this would be, for example, a needle holder) in order
to provide compensation, so that the hand tremor cannot be observed
at the tip.
[0005] Since the physiological tremor takes place in a range of
between about 5 and 15 strokes/second, it can be differentiated
from slower voluntary movements, for example by frequency-selective
filtering.
[0006] Movement Detection
[0007] According to the invention, one or more devices can be
provided for detecting movements on the part of the user, in
particular for detecting movements of the instrument caused by the
user, for example active or passive measurement transducers, by
means of which undesired movements on the part of the user, or
movements of the instrument caused by the user, can be detected.
The output signals from these devices are used, if appropriate
after suitable evaluation and processing, to trigger actuators of
the instrument for the purpose of compensating for the undesired
movements.
[0008] To detect the movement of the instrument, a number of
possibilities can be selected in principle, and these can be
combined with one another:
[0009] 1. Acceleration and angular velocity sensors are arranged on
one or more sections of the instrument, which sensors supply a
mechanical or electrical signal correlated with the movement of the
instrument.
[0010] The function of the sensors can be based on purely
mechanical, electromagnetic, capacitive, piezoelectric or
piezoresistive principles. The sensors have to detect the movement
with sufficient sensitivity and accuracy. In this connection, it is
conceivable to use sensors which have their maximum sensitivity in
the frequency range in which the undesired movements take place and
thereby deliver an output signal correlated with the tremor. The
sensors can be arranged in such a way that they can detect both
translational movements and rotational movements of the
instrument.
[0011] 2. According to the invention, one or more devices can be
provided for repetitive or continuous detection of the position of
certain sections of the instrument in one, two or three dimensions,
in particular of a handheld section and/or a section of the
instrument which is movable in relation to the handheld section. By
repetitive or continuous detection of the position and orientation
of certain sections of the instrument, their movement can be
followed. The detection can take place in one, two or three
dimensions. This can be done by wireless means via a
transmitter/receiver system on the instrument and at reference
points which are located at fixed positions in space or on the area
being worked on.
[0012] It is also possible, particularly for use in microsurgery,
to follow the movement of the section of the instrument shown in
the operating microscope. The microscope image is delivered to an
image-recording unit which determines the positions, in the image,
of certain features or optical markings on the instrument and
calculates the movement on the basis of the consecutive position
data. To do this, tracking procedures can also be used.
[0013] If, in addition, the movement of the tissue being worked on
is also detected, this movement likewise being shown under the
operating microscope, the movement of this tissue caused, for
example, by the tremor on the part of the patient can be included
in the compensation process.
[0014] 3. With surface electrodes arranged on the skin of the
person operating the instrument, the action potentials of the
underlying muscle can be recorded (so-called electromyography). If
a control system recognizes the movement which the corresponding
muscle causes on innervation--for example through the ability to
adapt--it is possible, by combining the electrode signals, to draw
conclusions regarding the deflection the instrument is expected to
make. In this method, the actual use of the instrument would be
preceded by a "learning phase" in which the signal processing unit
correlates the electromyographic signals with results of other
movement-recording methods, and thus adapts to individual features
of the operator and to the positioning of the reference
electrodes.
[0015] Signal Processing
[0016] If the movement detection has not already supplied a signal
which corresponds to the movement attributed to the tremor and is
thus suitable for directly triggering the actuators, the signal is
processed.
[0017] In general, it will first be necessary to amplify the sensor
signal. This is followed by analysis which differentiates between
intentional and unintentional movements on the basis of criteria
such as frequency, amplitude, speed and direction. The criteria can
be predefined, adjusted, or adapted automatically. On the basis of
the data, a signal is obtained with which the actuators are
triggered so that said actuators execute, at the working tip of the
instrument, relative movements for compensating for the undesired
deflections of the handheld section.
[0018] Actuators
[0019] The actuators can be both purely mechanical arrangements and
also electrical controls which are based, for example, on
electromagnetic, capacitive or piezoelectric principles. The
actuators execute relative movements between the handheld section
and the movable section of the instrument. They must be able to
execute the desired movements with sufficient speed, power and
precision. The actuators can be arranged in such a way that they
can effect both translational movements and rotational movements.
For certain requirements, it may be desirable that the actuators
can also temporarily bring about a rigid connection between the
handheld section and the movable section. The working tip of the
instrument can be mounted in a fixed manner or can be designed to
be exchangeable. Actions, such as the opening and closing of
grippers or forceps, which must necessarily be done from the
handheld section of the instrument, can be triggered via a flexible
power transmission, for example a flexible push rod, which does not
impede the actuators, or via electrically operated adjustment
members on the moved section.
[0020] Additional Functions
[0021] It may be useful, especially for use in microsurgery, to
trigger the actuators already present in the instrument by means of
a push button in such a way that they cause the working tip of the
instrument to oscillate at frequencies in the sonic or ultrasonic
range, and, for example, when used as a needle holder, facilitate
the penetration of the suture needle into tissue, as a result of
the rapid micro-movements.
[0022] Illustrative Embodiment
[0023] An illustrative embodiment of the invention is explained in
greater detail below, with reference to the attached drawings.
[0024] In FIG. 1, reference (1) designates the handheld section of
a medical instrument. Groups of acceleration meters and angular
velocity sensors (2) sit on this section. A movable section (4) is
connected to the handheld section (1) via a flexible connection
(5), and on this movable section (4) the working tip is, for
example, a needle holder. The movable section can be moved relative
to the handheld section (1) by the arrangement of piezoelectric
actuators (3). The actuators (3) are arranged in such a way that
they can bring about deflections in all directions transverse to
the main axis of the instrument.
[0025] A control unit fed by a battery is located in the handheld
section (1), said control unit amplifying the data supplied by the
sensors (2), continuously analyzing this data and comparing it.
[0026] On the basis of adaptable criteria such as acceleration,
frequency, direction and amplitude of the movement, the control
unit differentiates between desired movements and the hand tremor
of the operator.
[0027] To compensate for the hand tremor, the arrangement of the
actuators (3) is triggered in combination in such a way that these
effect relative movements of the movable part (4) which are adapted
in direction, speed and amplitude, and the undesired movements of
the hand grip (1) cannot be observed at the working tip of the
instrument holder (4). For opening and closing needle holders,
forceps or scissors, use is made of a push rod (7) which flexibly
designed in the area of the flexible connection (5) and which
extends through the inside of the movable section (4). The push rod
is operated via a lever (6). A flexible membrane (8) on the end
face of the handheld section (1) is used to seal off the
mechanism.
[0028] The function of the instrument is additionally shown in FIG.
2.
[0029] A rapid and unintentional pitching movement of the handheld
section (4), caused by tremor, would lead to an undesired
deflection of the working tip (11) of the instrument. In order to
prevent this, the actuators (3) are triggered for compensation so
that the movable section (4) is moved in the opposite direction,
and the working tip (11) remains at rest.
* * * * *