WO1996029015A1

WO1996029015A1 - Method and apparatus for detecting and displaying successive positions of osseous stumps

Info

Publication number: WO1996029015A1
Application number: PCT/IT1996/000049
Authority: WO
Inventors: Terenzio Poeta; Roberto Poeta; Giovanni Renzi Brivio; Lodovico Renzi Brivio
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-03-20
Filing date: 1996-03-18
Publication date: 1996-09-26
Anticipated expiration: 1997-09-20
Also published as: AU4953196A; IT1278934B1; ITBS950026A0; ITBS950026A1

Abstract

A method and an apparatus for detecting and displaying successive positions of osseous stumps is described which involves: detecting, by an acquisition unit (101), the osseous stumps (3, 3') at at least one initial position; detecting the displacements of each of the osseous stumps (3, 3') instant by instant, and associating to each stump predetermined movement parameters corresponding to the relative displacements to which said stumps are submitted; and computing the successive positions reached by the osseous stumps (3, 3') instant by instant, based on the detection of the position of the osseous stumps and the movement parameters. A displaying unit (104) displays the successive positions of the osseous stumps, instant by instant.

Description

METHOD AND APPARATUS FOR DETECTING AND DISPLAYING

SUCCESSIVE POSITIONS OF OSSEOUS STUMPS

D e s c r i p t i o n

The present invention relates to an apparatus -For detecting and displaying successive positions o-f osseous stumps. It is known that in the traumatological and orthopedic field, for treatment of fractures or other infractions, wide use is made of axially external fastening means which substantially comprises stiff elements applied to the stumps by fastening screws through which the orthopedic physician can move the stumps until achievement of a perfect alignment of same. During these operating steps, the verification of the successive positions taken by the osseous stumps is carried out by radiographic apparatuses that continuously radiate the body portion, a limb for example, to be treated.

Clearly, the above described technique suffers from some drawbacks. First of all, it is to note that both the patient and the medical staff assigned to the task are constantly exposed to the radiation emitted by the radiographic apparatus which is necessary for continuously detecting the successive positions taken by the osseous stumps. In addition, determining the occurred alignment of the osseous stumps in a precise manner is often very difficult, in particular when comminuted fractures are to be treated. Under this situation, the main object of the present invention is substantially to obviate the above mentioned drawbacks by providing a method and an apparatus capable of detecting and displaying successive positions of osseous stumps, in which the use of radiations or waves of other nature which are presently necessary for monitoring the positions of the osseous stumps are minimized.

It is a further object of the invention to provide a method and an apparatus enabling alignment of the osseous stumps to be carried out in a very precise and quick manner.

The foregoing and further objects that will become more apparent in the progress of the present description are substantially achieved by a method as set forth in claim 1 and an apparatus as described in claim 5.

Further features and advantages will be more fully understood from the detailed description of a preferred but non-exclusive embodiment of a method and an apparatus for detecting and displaying successive positions of osseous stumps in accordance with the present invention, taken hereinafter by way of non¬limiting example, with reference to the accompanying drawings, in which:

- Fig. 1 is an axonometric representation of a preferred embodiment of transducer means in an apparatus in accordance with the invention in which the rotatory and axial movements that the different elements forming said transducer means can perform are shown by arrows;

- Fig. 2 is a view taken along line A-A in Fig. 1;

- Fig. 3 is a view taken along line B-B in Fig. 2;

- Figs. 4 and 5 are views similar to those in Figs. 2 and 3 respectively, in which also diagrammatically shown is sensor means the presence of which is necessary for detecting the relative movements between the different elements forming the transducer means in accordance with the invention;

- Fig. 6 is an axonometric view of the transducer means in accordance with the invention, operatively associated with two osseous stumps to be aligned; and

- Fig. 7 is a schematic block diagram of an apparatus in accordance with the invention.

With reference to the drawings, and in particular to Fig. 7, an apparatus for detecting and displaying successive positions of osseous stumps in accordance with the present invention has been generally denoted by 100.

Apparatus 100 comprises an acquisition unit 101 which may consist of a radiographic apparatus, an ultrasonic apparatus or any other apparatus adapted to detect the position and conformation of osseous portions within a human or animal body.

The acquisition unit 101 is arranged to carry out at least one detection of the osseous stumps 3, 3' to be aligned at at least one initial position. Preferably, this acquisition unit carries out a predetermined number of starting detections of the osseous stumps, so as to determine the initial position of same in a precise manner and be able to identify the contours of said stumps in a very precise manner, above all at the area afflicted with a fracture.

The acquisition unit 101 transmits its detections to analog-to-digital conversion means, denoted by 102, which is operatively interposed between the acquisition unit 101 and a processing unit 103 which is capable of reconstructing the outline of the osseous stumps and therefore the image of same and to transmit it instantaneously to a display unit identified by 104 and normally consisting of a conventional graphic display screen. It is to note that the analog-to-digital conversion means 102 may be directly incorporated into the acquisition unit or be physically separated therefrom without involving any change in the logical sequence of the above described passages.

Apparatus 100 further comprises transducer means 105 operatively associated with the osseous stumps 3, 3' and arranged to detect predetermined movement parameters and to generate output drive signals corresponding to relative displacements to which said osseous stumps are submitted. This transducer means 105 too is operatively connected to analog-to-digital conversion means 102 intended for carrying out conversion of the analog-type drive signals to digital drive signals to be interpreted by the processing unit 103 which, as shown in Fig. 7, is also operatively connected to the transducer means. In this manner, the processing unit 103 can calculate the successive positions of the osseous stumps based on the drive signals from the transducer means and on detection of the initial position of the osseous stumps carried out by the acquisition unit 101. Thus, the processing unit reconstructs the image of the osseous stumps in the successive positions they take over time and transmits this image to the unit 104 to enable displaying of the osseous stumps at such successive positions.

It is to note that, from a structural point of view, the transducer means can be made following different modalities. In particular, provision may be made for transducer means either of a substantially mechanical type, as in the embodiment shown, or of an optical, acoustic, electromagnetic type or still other types. What is essential is that this transducer means must be capable of detecting the relative movements between the two osseous stumps to be aligned and transmitting these movements in the form of a predetermined sufficient number of parameters, so as to reconstruct the successive positions taken by the osseous stumps, instant by instant.

As already said above, the transducer means shown in the accompanying drawings are of the electromechanical type and comprises a given number of stiff elements S1, S2, S3, S4, S5 consecutively in engagement with each other, and detector means E1, E2, E3, E4 , E5, E6 operatively interposed between each pair of adjacent stiff elements to cause the relative movement of said stiff elements, by detecting the corresponding movement parameter and then generating the corresponding output drive signal.

More particularly, a first stiff element S1 is provided which is fastened to one 3 of said osseous stumps, 3 and 3', by means of a bracket 5 for example. Rotatably and consecutively connected to the first stiff element S1 is a second stiff element S2 which can rotate relative to said first stiff element according to a first rotation axis A1. A third stiff element S3 is rotatably and consecutively linked to the second stiff element S2 and can rotate according to a second and a third rotation axes A2, A3 perpendicular to each other and to the first rotation axis A1. Also provided is a fourth stiff element S4 rotatably and consecutively connected to said third stiff element according to a fourth and a fifth rotation axes A4 and A5 perpendicular to each other. Finally, the apparatus comprises a fifth stiff element S5 fastened, by another bracket 5 for example, to the second one 3' of said osseous stumps 3 and 3' to be aligned. It is to note that the fourth stiff element S4 is also connected to the fifth stiff element S5 in such a manner that it can slide in a predetermined slide direction A6 perpendicular to said fourth and fifth rotation axes A4, A5.

For ease of understanding, the movements performed by the different stiff elements S1, S2, S3, S4, S5 about axes A1, A2, A3, A4 , A5 and along axis A6 are identified by the respective arrows F1, F2, F3, F4, F5, F6.

It is to note that, from a manufacturing point of view, the above described rotations are obtained by universal joints identified by G1 and G2 in the accompanying drawings and by appropriate geared kinematic mechanisms housed in casings C1, C2, C3 and C4. As regards sliding in the direction A6, this last movement is obtained by cylindrical guide columns M1, M2 operating between the stiff elements S5 and S4. As to the above mentioned detector means, it comprises a first sensor member E1 operatively interposed between the first and second stiff elements S1, S2 to detect a first one of said movement parameters corresponding to a rotation about said first axis A1. Also provided is a second and a third sensor members E2 and E3 operatively interposed between the second and third stiff elements S2, S3 to detect a second and a third one of said movement parameters corresponding to a rotation about said second axis A2 and a rotati on about sai d th i rd ax i s A3 , respect i vel y. Also provided is a fourth and a fifth sensor members E4 and E5 operatively interposed between the third and fourth stiff elements S3, S4 to detect a fourth one and a fifth one of said movement parameters which correspond to a rotation about said fourth axis A4 and a rotation about said fifth axis A5, respectively. Finally, a sixth sensor member E6 is provided which is operatively interposed between the fourth and fifth stiff elements S4, S5, to detect a sixth one of said movement parameters corresponding to a translation along said slide axis A6. These sensor members E1, E2, E3, E4, E5, E6 may consist of conventional encoders for example, outputting a signal corresponding to the value of the movement parameter they have detected.

As can be viewed in particular from fig. 6, a fastening assembly 2 can be operatively associated with the above described transducer means, for clamping of the osseous stumps together when the alignment has been completed. It is to note that in this case the first and fifth stiff elements S1 and S5 will be rigidly linked to end portions of the fastening assembly 2 by means of the above mentioned brackets 5 for example. Advantageously, apparatus 100 further comprises a first and a second working elements each denoted by 6 and respectively fastened to the first and fifth stiff elements S1 and S5. Each of said working elements is also secured to a respective one of the osseous stumps 3, 3' and to a respective end of the fastening assembly 2.

Finally, it is also provided to advantage that the apparatus 100 should comprise means for signalling a correct alignment of the osseous stumps. This means may be either of a hardware type, associated with the transducer means for example, or of a software type, that is implemented in the processing unit 103. In the latter case, the signalling means substantially consists of a routine which is capable of constantly controlling the position reached by the osseous stumps while at the same time verifying whether these stumps are conveniently aligned, above all close to the area concerned with the fracture.

After describing the apparatus 100 according to the invention mainly as regards structure, the operating steps performed by said apparatus will be now illustrated in more detail.

These operating steps put into practice a method of detecting and displaying successive positions of osseous stumps, which method too is the object of the present invention.

In accordance with said method, an operating step is first provided in which detection of the osseous stumps 3 and 3' at at least one initial position is carried out through the acquisition unit 101. Practically, the first operating step can be repeated several times in order to determine the outline of the osseous stumps in a very precise manner, as well as their spatial position at the starting instant.

Subsequently, the acquisition unit is cut out or turned off and a detection step is carried out for detecting the displacements of each of the osseous stumps 3 and 3' instant by instant, and predetermined movement parameters, corresponding to the relative displacements to which said osseous stumps are submitted, are associated with each stump. Then a computing step is executed in which the successive positions reached by the osseous stumps 3, 3' are calculated, instant by instant, based on said detection of the initial position of the osseous stumps and detection of said movement parameters. Then the outline of the osseous stumps in the different successive positions they tar-e is displayed, instant by instant. During these steps an additional checking step is also provided, which is carried out instant by instant too and aims at verifying the correct alignment of the osseous stumps. When, as a result of said checking step, the correct alignment of said osseous stumps is ascertained, a signalling step for the operator is also provided, so that the latter may stop movement of the osseous stumps and carry out clamping of said osseous stumps together, by means of said fastening assembly 2, for example.

The invention achieves important advantages.

It should be noted in fact that by virtue of the method and apparatus in accordance with the invention, radiation to which both the patient and medical staff are subjected is reduced to a minimum. In fact this radiation is only indispensable in the starting step of the operation for identifying the initial position of each of the osseous stumps.

In addition, the method and apparatus in question enable the alignment operation to be carried out with the greatest accuracy after a precise detection of the initial position. In fact, the processing unit enables the successive positions to be computed with the greatest precision without mistakes due to inexactitudes in the radiographic apparatus being possible, above all during the movement of the osseous stumps.

The apparatus in reference is also very practical, because it signals to the operator that the condition of perfect alignment between the osseous stumps has been reached.

It is also important to point out that the apparatus being the object of the present invention is advantageous in its most specific aspects.

In fact, the transducer means as shown in the preferential solution depicted in the accompanying figures 1 to 6 is of easy and cheap manufacture; setting up of said transducer means is easy and practical also in cooperation with fastening assemblies of known type and, in addition, said means is very reliable over time, due in particular to the use of simple articulated structures and conventional encoders.

Obviously, many modifications and variations may be made to the present invention without departing from the inventive scope characterizing it.

Claims

C L A I M S

1. A method of detecting and displaying successive positions of osseous stumps, said method comprising the following steps:

- carrying out detection, by an acquisition unit (10), of said osseous stumps (3, 3') at at least one initial position;

- detecting the displacements of each of said stumps (3, 3'), instant by instant, and associating with each stump predetermined movement parameters corresponding to the relative displacements to which said stumps are subjected;

computing, instant by instant, the successive positions reached by said osseous stumps (3, 3'), based on said detection of the osseous stump position and said movement parameters;

- displaying said successive positions of the osseous stumps, instant by instant.

2. A method according to claim 1, characterized in that said movement parameters are detected by transducer means (105) generating output drive signals of an analog type.

3. A method according to claim 1, characterized in that a checking step is carried out instant by instant to inspect alignment of the stumps themselves.

4. A method according to claim 3, characterized in that on reaching of a relative position of correct alignment between said osseous stumps (3, 3'), a signalling step to an operator is provided.

5. An apparatus for detecting and displaying successive positions of osseous stumps comprising:

- an acquisition unit (101) arranged to carry out at least one detection of said stumps (3, 3') at at least one initial position;

- a displaying unit (104) operatively associated with said acquisition unit (101),

characterized in that it further comprises:

- transducer means (105) operatively associated with said osseous stumps to detect predetermined movement parameters and generate drive signals corresponding to relative displacements to which said osseous stumps are submitted; and

- a processing unit (103) operatively connected to said acquisition unit (101) and said transducer means (105), said processing unit computing the successive positions of said osseous stumps (3, 3') instant by instant, based on said drive signals and detection of said initial position of the osseous stumps themselves, said processing unit (103) being also connected to said displaying unit (104) to display the osseous stumps at said successive positions.

6. An apparatus according to claim 5, characterized in that said acquisition unit (101) comprises a radiographic apparatus.

7. An apparatus according to claim 5, characterized in that said acquisition unit (101) comprises an ultrasonic apparatus.

8. An apparatus according to claim 5, characterized in that said acquisition unit (101) carries out a predetermined number of starting detections of said osseous stumps to determine the initial position of the latter in a precise manner.

9. An apparatus according to claim 5, characterized in that it comprises analog-to-digital conversion means

(102) operatively interposed between said acquisition unit (101) and said processing unit (103).

10. An apparatus according to claim 5, characterized in that it comprises analog-to-digital conversion means (102) operatively interposed between said transducer means (105) and said processing unit (103).

11. An apparatus according to claim 5, characterized in that said transducer means comprises:

- a predetermined number of stiff elements (S1, S2, S3, S4, S5) consecutively in engagement wich each other; and - detector means (E1, E2, E3, E4, E5) operatively interposed between each pair of adjacent stiff elements to cause the relative movement of the latter thereby detecting the corresponding movement parameter and generating the corresponding drive signal.

12. An apparatus according to claim 11, characterized in that said predetermined number of stiff elements comprises:

- a first stiff element (S1) fastened to one (3) of said osseous stumps (3 and 3');

- a second stiff element (S2) rotatably and consecutively connected to said first stiff element (S1) according to a first rotation axis (A1);

- a third stiff element (S3) rotatably and consecutively linked to said second stiff element (S2) according to a second and a third rotation axes (A2, A3) perpendicular to each other and to the first rotation axis (A1);

- a fourth stiff element (S4) rotatably and consecutively connected to said third stiff element (S3) according to a fourth and a fifth rotation axes (A4, A5) perpendicular to each other;

- a fifth stiff element (S5) fastened to the second one (3') of said osseous stumps (3, 3') to be aligned, said fourth stiff element (S4) being also connected to the fifth stiff element (S5) according to a predetermined slide direction (A6) perpendicular to said fourth and fifth rotation axes (A4, A5).

13. An apparatus according to claim 11, characterized in that said detector means comprises:

- a. first sensor member (E1) operatively interposed between said first and second stiff elements (S1, S2) to detect a first one of said movement parameters corresponding to a rotation about said first axis (A1):

- a second and a third sensor member (E2, E3) operatively interposed between said second and third stiff elements (S2, S3) to detect a second and a third one of said movement parameters corresponding to a rotation about said second axis (A2) and a. rotation about said third axis (A3), respectively:

- a fourth and a fifth sensor member (E4, E5) operatively interposed between the third and fourth stiff elements (S3, S4) to detect a fourth one and a fifth one of said movement parameters which correspond to a rotation about said fourth axis (A4) and a rotation about said fifth axis (A5), respectively;

- a sixth sensor member (E6) operatively interposed between said fourth and fifth stiff elements (S4, S5), to detect a sixth one of said movement parameters corresponding to a translation along said slide axis (A6).

14. An apparatus according to claim 1, characterized in that a fastening assembly (2) is operatively associated with said transducer means for clamping of the osseous stumps (3, 3') together when alignement has been carried out.

15. An apparatus according to claim 14, characterized in that said first and fifth stiff elements (S1, S5) are rigidly linked to end portions of said fastening assembly (2).

16. An apparatus according to claims 13 and 14, characterized in that it further comprises a first and a second working elements (6) fastened to the first and fifth stiff elements (S1, S4) respectively, each of them being also fastened to a respective osseous stump (3, 3') and to a respective end of said fastening assembly (2).

17. An apparatus according to claim 1, characterized in that it further comprises means for signalling a correct alignment of the osseous stumps.