WO1998040718A1

WO1998040718A1 - Instrument for qualifying the mechanical preservation status of biological surfaces

Info

Publication number: WO1998040718A1
Application number: PCT/ES1998/000060
Authority: WO
Inventors: Pedro Guillen Garcia
Original assignee: Asociacion Instituto De Biomecanica De Valencia; Fundacion Mapfre Medicina
Priority date: 1997-03-10
Filing date: 1998-03-10
Publication date: 1998-09-17
Also published as: ES2120916A1; AU6623398A; ES2120916B1

Abstract

The instrument is comprised of processing means in order to qualify the force exerted on biological surfaces and the collapse caused by said force, said means being characterized in that they are portable and comprise a case with indentation means (1) including a housing for a strip (6) carrying the displacement transducer (12), as well as means for supporting (13, 15 and 34) the indentation means (1), between which is interleaved the force transducer (20) so that when applying a force to the biological surface, after having done the indentation, the strip (6) is displaced and the mechanical preservation condition of said surface is known through the processing means.

Description

INSTRUMENT FOR SANCTIFICATION OF THE MECHANICAL STATE OF CONSERVATION OF BIOLOGICAL SURFACES

DESCRIPTION

OBJECT OF THE INVENTION

The present invention, as expressed in the statement of this specification, consists of an instrument for the quantification of the mechanical state of conservation of biological surfaces, of the type that have means of processing two signals obtained from two transducers, one of which provides a signal proportional to the force applied to the biological surface and, the other, a signal proportional to the sinking that occurs on said surface when the said force is applied, so that the processing means quantify the mechanical state of conservation from these parameters.

Well, the object of the invention is to empower the quantification of the mechanical state of preservation, by means of indentation techniques, of the type used in arthroscopy, damaging the patient as little as possible.

Another object of the invention is to provide a portable instrument for the quantification of the mechanical state of conservation of biological surfaces, so that its handling is simplified and considerably facilitated.

BACKGROUND OF THE INVENTION

The degeneration of biological surfaces, for example, articular cartilage is associated with changes in the mechanical properties of the material, among others its stiffness. Said variations in rigidity are affected both by its aging and by pathological or degenerative processes.

For this reason, a number of devices have been developed that allow the cartilage stiffness value to be obtained from the load-deformation curves of the material, for different conditions of age, wear and thickness.

All these devices have the disadvantage that they require that free access to cartilage be granted, for which the corresponding area in which said cartilage is to be opened, so after making such a measurement, it is necessary to sew the open area

In addition, these types of devices have a considerable volume, which considerably hinders their transport, so it must be the patient who has to move to the location of the measuring device, which also constitutes an inconvenience.

DESCRIPTION OF THE INVENTION

In order to solve the aforementioned drawbacks, the invention is characterized in that it has indentation means that include a housing for a carrier strap of the transducer or subsidence suffered by the biological surface.

It also includes support means for the indentation means, between which the transducer is inserted of force so that when applying the force on the biological surface, after carrying out the indentation, the displacement of the strapping takes place, obtaining the force and displacement in the processing means, which quantify the mechanical state of conservation.

The indentation means are determined by a hollow cylindrical body whose front end is closed and in proximity thereto has a hole or opening in one of whose edges has an orthogonal appendix whose tip constitutes the means to apply the force on the biological surface.

The hollow cylindrical body is provided with a longitudinal opening diametrically opposed to the hole in which the strap is arranged. The strap has at its end a bend that defines a small section that passes through the hole of the cylindrical body, so that said end is flush with that of the appendix. The other end of the strap is fixed by a flange at the back of the longitudinal opening.

The displacement quantification transducer that undergoes strapping, when applying the force on the biological surface, is determined by a gauge, which are the sensors used in extensometry, which forms a Wheatstone bridge, together with three resistors located in the means of conditioning.

The force transducer is determined by an annular body equipped with four sensors that form a Wheatstone bridge.

On the other hand, the support means have a hollow cylinder in which the hollow cylindrical body of indentation is inserted and fixed. In addition, the support means have a head in which the annular body, which constitutes the force transducer, is fixed, so that the hollow cylinder is inserted into the head through the annular body and fixed between them by interposing sectors, so that when the force is applied in the appendix it is transmitted to the annular sensor.

The head is attached to a hollow handle in which the electronic conditioning means of the signals obtained in the transducers are housed.

The electronic signal conditioning means are located between two longitudinal frames whose assembly is fixed by two extreme discoid parts, so that the extraction of the electronic means is enabled to allow sterilization of the rest of the elements, whereby the handle is its rear part includes a thread in which a plug is placed which constitutes the means of facilitating access for the extraction and introduction of electronic means.

The extreme discoidal parts that constitute the means of joining the longitudinal frames and the plate that supports the electronic means of signal conditioning, have holes, one of which constitutes the means through which a connector emerges that is positioned in the head, while the other is the middle of the passage of a cable for connection to an isolation amplifier.

The isolation amplifier constitutes the means that allows the connection to a computer or a processing card of the signals obtained in the transducers and treated in the signal conditioning means. The signal conditioning means are powered by rechargeable batteries so that the instrument together with the features already discussed above, is fully portable, for which it can be included in a case along with the battery charger, connection cables and amplifiers of isolation.

Next, in order to facilitate a better understanding of this descriptive report and forming an integral part thereof, a series of figures are attached in which the object of the invention has been represented by way of illustration and not limitation.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being carried out and in order to facilitate the best and easiest understanding of the characteristics of the invention, a set of drawings is attached as an integral part thereof, with Illustrative and never limiting, we have proceeded to represent the following:

Figure 1 shows an exploded perspective view of the exploded view of the instrument for measuring the quantification of the mechanical state of conservation of biological surfaces, object of the invention.

Figure 2 shows a view according to a longitudinal section of the assembled instrument assembly, except for the electronic means that are partially inserted.

Figure 3 shows a partial view and sectioned of the detail of the arrangement of the strip on the indentation means as well as the location of the different elements in the head.

Figure 4 shows a view according to a longitudinal section of the indentation bar.

Figure 5 shows a plan view of the previous figure.

Figure 6 shows a section along the axis A-A of figure 4.

Figure 7 shows a plan view of the strip in order to show the location of the sensor.

Figure 8 shows a side view of the strap of the previous figure.

Figure 9 shows a view according to a longitudinal section of the cylindrical body that supports the indentation bar of Figures 4, 5 and 6.

Figures 10 and 11 show a view of the sectors through which the force transducer is coupled.

Figure 12 shows a bottom plan view of the flange by means of which the strap is fixed in the cylindrical element 1.

Figure 13 shows a sectional view along the C-C axis of the previous figure.

Figure 14 shows a view according to the section DD of the previous figure.

Figure 15 shows a view according to a longitudinal section of the head that supports the indentation means.

Figure 16 shows a view according to a section B-B of the previous figure.

Figure 17 shows a view of the cap that is screwed to the head, this view being partially sectioned.

Figure 18 shows a front view of one of the racks that support electronic media.

Figure 19 shows a view according to section E-E of the previous figure.

Figure 20 shows a front view of the other frame constituting the means for holding the electronic means.

Figure 21 shows a longitudinal section along the axis F-F of the previous figure.

Figure 22 shows a front view of one of the discoid elements that provide for fixing the longitudinal frames and the electronic means.

Figure 23 shows a plan view of a portable case in which the instrument of the invention is included as well as the elements necessary for its operation. Figure 24 shows an example of application, to quantify the mechanical state of conservation of a biological surface.

PREFERRED EMBODIMENT OF THE INVENTION

Below is a description of the invention based on the figures mentioned above.

The instrument for the quantification of the mechanical state of conservation of biological surfaces of the invention, presents as a characteristic, the fact of empowering the execution of said quantification, without the need to open the area that precedes the biological surface that it is desired to check its status, that is, it allows its use by means of the indentation technique in a way that allows to examine the mechanical properties of the entire biological surface and to represent the variations of these properties with its topography. The equipment will be used mainly in arthroscopic examinations, which implies very restrictive design conditions.

To achieve the aforementioned objectives, the invention has an indentation bar that is constituted from a cylindrical body (1), one of whose ends is topped by a hemispherical cap (2) from which and in the area At the bottom, a hole (3) is provided, which is flanked by an appendix (4) whose tip constitutes the means to apply the force on the biological surface, as will be described later.

In addition, the cylindrical body (1) is provided with a longitudinal opening (5) on which a strap (6) is placed at the end of which a bend has been made that defines a small section (7) that passes through the hole (3), all so that the end of the section (7) flush with the end of the appendix (4).

The fastening of the strap (6) is carried out through a flange (8) whose upper surface is semicircular and adapts perfectly to the cylindrical body (l), so that it is arranged as an extension thereof.

The flange (8) has a thread (9) in which a screw (10) is tightened through a hole (11) arranged in the cylindrical body, leaving the flexible tongue (6) perfectly retained.

On the tongue (6) a gauge or gauge (12) is included which together with three resistors constitutes a Wheatstone bridge, the functionality of which will be described later.

The cylindrical body (1) is housed and fixed in a hollow cylinder (13) in whose anterior and internal part it has a section (14) of greater diameter in which the cylindrical body (1) is housed and fixed.

In addition, the instrument of the invention has a head (15) in which the front part is provided with a thread (16) in which a cover (17) equipped with a hole (18) is attached through which the cylindrical body (13) inside the head (15).

The head (15) has a first zone

(19) which includes a force sensor that is determined by an annular body (20) through which the cylindrical body (13) runs, fixing it and the head (15), by interposing a sector (22) and (23) respectively whose location is shown in figures 2 and 3 and whose structure is represented in the figures 10 and 11. Note that these sectors are arranged one on the inside of the annular body and the other on the outside, so they have different curvatures.

To allow the passage and fixation of the screws (21), the head (15) has the hole (24) and the cylindrical body (13) with the threaded hole (25).

The rear end of the cylindrical body (13) is located in the area (26) of the head (15), in which it is fixed by means of a screw (27).

The head (15) has a zone (28) that after a step defines a zone (29) that constitutes the rear opening of the head, so that said step constitutes the means of location of a discoidal piece (32) that is fixed by screws

(33) in the holes (30) made in the head.

Another of the elements that constitute the instrument of the invention is determined by a handle

(34) that is housed in the area (29) of the head (15), where it is fixed through the holes (31) by means of screws (35).

The handle (34) is constituted by a hollow cylindrical body in which a button (36) is included, whose functionality will be described later.

Inside the handle (34) an electronic circuit is housed that is supported by two racks fluted (37) and (38) between which a support (39) is sandwiched, joining these elements at their ends by means of discoid parts (40) and (41) through the corresponding screws (42).

An electronic circuit whose functionality will be described later is included in the support (39).

The discoidal piece (40) has an opening

(43) and with a central hole (44) through which the connector of the electronic circuit with the force transducer and with the displacement transducer arranged in the strap (6) goes outside.

The frame (37) is provided with a slot (45) that is located in correspondence with the opening (43) of the disk piece (40), so that to make the insertion of the electronic circuit, said slot (45) must be positioned in correspondence with the button (36), so that this constitutes a guiding means when introducing the electronic circuit.

The transducers located in the strip and inside the head, are related to a connector provided in the area (28) of the head (15), and by means of the corresponding cables that run through the different cylindrical bodies.

Thus, when the electronic circuit is introduced, and after being guided as already mentioned, the electronic circuit is connected through the corresponding connector with the force and displacement transducers. The electronic circuit includes a power battery, so that when the connection is made correctly, an indicator light on the handle (34) comes on.

Once the electronic circuit has been inserted inside the handle (34), it is sealed by a plug (48) through which the connection cable of the electronic circuit to a computer or a processing card comes out, which processes the data obtained in the electronic circuit.

At this point it should be noted that the connection of the electronic circuit to the computer or processing card is made by means of an isolation amplifier (46).

The description of the operation of the instrument of the invention follows.

To carry out the indentation, the end of the appendix (4) and the end of the section (7) of the strap (6) are placed on the biological surface to be explored and the force is applied on it (figure 24) with which the end of the appendix (4) produces a subsidence of the biological surface, so that the strip (6) undergoes a displacement produced by said subsidence, which is detected by the sensor (12) that is part of the Wheatstone bridge included in the electronic circuit, so that it effects the conditioning of said signal for its subsequent treatment or interpretation.

The force exerted on the appendix (4) is transmitted along the entire cylindrical body (1) and from it passes to the cylindrical body (13), which transmits the force to the annular body (20) that constitutes the force transducer, this signal being conditioned in the electronic circuit included in the handle (34) of the device of the invention.

The conditioned signals can be sent to the processing card or to the computer through the isolation amplifier, which has not been represented as being evident.

The push-button (36) allows the equipment to be switched on and also set to zero, which allows different measurements to be made to obtain the load-displacement curves of the biological surface.

The fact that the electronic circuit located inside the handle (34), can be removable, is due to the fact that it is necessary to perform the sterilization of the instrument, for which the entire device is introduced in an autoclave that reaches temperatures of 130 ° , circumstance that the electronics do not support, so it is necessary that it can be extracted. From the above, it is evident that both the transducers and the wiring to the connector are suitable for being able to undergo the sterilization process.

The described device has the peculiarity that it is easily transportable, and manageable, so that it can be easily included and transported in a portable case (47) in which the isolation amplifier (46) is included the set determined by the racks ( 37), (38) and the support (39) which includes the electronic signal adaptation circuit, the cover

(48), a battery charger (49), and the network connection cables (50). This description does not become more extensive, in the good understanding that any expert in this field would have enough information to understand the scope of the invention and its derived advantages, as well as to proceed to reproduce it.

It is understood that, if they do not alter the essentiality of the invention, both the variations in the materials and the shape, size and arrangement of the elements are susceptible to variation within the same characterized.

The terms used during the description and the meaning of it should always be considered in a non-limiting manner.

Claims

l.- Instrument for the quantification of the mechanical state of conservation of biological surfaces, of the type that have means of processing two signals obtained from two transducers, one to measure a force applied on the biological surface and another to measure the sinking or displacement that occurs on the biological surface when applying the force that, essentially, is characterized in that it has indentation means that include a housing for a carrier strap of the displacement or subsidence transducer, also having support means of the indentation means between which the force transducer is inserted, so that when applying the force on the biological surface, after carrying out the indentation, the displacement of the strip occurs, allowing the measurement of the force exerted and the displacement obtained, of so that the value of the mechanical state of preservation is obtained in the processing means ón of the biological surface.

2. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 1, characterized in that the indentation means are determined by a hollow cylindrical body whose front end is closed and in proximity to it has a hole (3 ) on one of whose edges it has an appendix (4) whose tip constitutes the means to realize the force on the biological surface; having provided that the hollow cylindrical body (1) allows the fastening of the strap (6).

3. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to the preceding claims, characterized in that the strapping (6) has at its end a bend that defines a small section (7), which passes through the hole (3) of the cylindrical body (1), whose end is flush with that of the appendix, and whose other end is fixed by a flange (8) in the cylindrical body.

4. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 1, characterized in that the transducer measuring the displacement or sinking of the biological surface is determined by a sensor (12) (gauge) that forms a Wheatstone bridge along with three resistors located in the support means.

5. Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 1, characterized in that the force transducer is provided with four sensors that form a Wheatstone bridge.

6. Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 1, characterized in that the support means have a hollow cylinder (13) in which the indentation means are inserted and fixed.

7. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 1, characterized in that the support means also have a head (15) into which the hollow cylinder (13) is inserted and fixed.

8. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claims 1 and 7, characterized in that inside of the head (15) the force transducer (20) is fixed, so that the hollow cylinder (13) runs through it and is fixed between them so that when the force in the appendix (4) occurs, it transmits to the force transducer (20).

9. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claims 1 and 7, characterized in that the head is fixed to a hollow handle in which it is included, with the possibility of extraction, totally or partially, of the means processing electronics, which include the resistances of the Wheatstone bridge as well as means of adapting the signals obtained in the transducers, so that said signals can be processed.

10. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claims 1 and 7, characterized in that the head (15) includes means for connecting the transducers with the electronic means for conditioning and signal processing .

11. An instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 1, characterized in that the support means have a handle (34) constituted by a hollow cylinder that joins the head (15), and in which includes the electronic means for conditioning and processing the signals from the transducers.

12. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claims l and 10, characterized in that the means Signal conditioning electronics are placed on a support (39) provided between two longitudinal frames (37 and 38) whose assembly is fixed by two extreme discoid parts (40 and 41).

13. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 12, characterized in that through one of the discoid parts a connector emerges that is positioned in the head (15), so that it is connected to the connector provided in it joining the electronic means with the transducers.

14. - Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to the preceding claims, characterized in that the electronic means for conditioning and signal processing are fed by rechargeable batteries.

15.- Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claim 11, characterized in that the handle (34) has a push button (36) that activates the electronic means and performs the zeroing thereof for empower the execution of different measures.

16.- Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to claims 12 and 15, characterized in that the longitudinal frame (37) has a groove (45) that is guided on the button (36), facilitating the connection between electronic means of conditioning and signal processing and transducers.

17.- Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to the preceding claims, characterized in that the electronic signal conditioning and processing means are connected to an isolation amplifier (46), by means of which the connection to the processing means that can be determined by a specific card or a personal computer.

18.- Instrument for the quantification of the mechanical state of conservation of biological surfaces, according to the preceding claims, characterized in that the indentation means as well as the support means thereof, together with a battery charger (49), connection cables and Isolation amplifiers (46), are arranged in a portable case (47).