FIELD OF APPLICATION

The present invention relates to a control of a surgical instrument.

More in particular, the present invention relates to a control of a surgical instrument achieved by exploiting detection sensors. PRIOR ART

It is well known that in the field of interventionist radiology, particularly in the case of minimally invasive percutaneous procedures, the insertion of probes, applicators and needles is often hindered by the impossibility of establishing the deformation/bending to which these instruments will be subjected.

Various systems aimed at detecting the deformation/bending of instruments used for minimally invasive procedures have been devised. Some are based on the use of optical fibres with different technologies. One example is the sensor described in patent US9636040B2 (Intuitive Surgical Operations Inc.), in which an optical fibre with a Bragg grating is rendered integral with the instrument and used to detect bending at the points on which each Bragg grating is located.

The sensor described in patent US8050523B2 (Philips), in which use is again made of a Bragg grating to detect bending, covers a type of technology similar to that of US9636040B2, as it relates to a sensor rendered integral with the instrument, whose bending it replicates. ITUB20155830A1 describes a fibre optic sensor based on dispersion zones. Through an area of discontinuity, the sensor, similarly rendered integral with the instrument, releases or holds back the light flow, allowing an estimation of bending.

“Estimating surgical needle deflection with printed strain gauges” [Hammond et al., 2014] describes a system for the manufacture of 500 micron strain gauges printed in large numbers directly on needles, and thus capable of detecting the deformations thereof along the needle itself. All of these methods are based on the use of sensors integrally fixed along the body of the surgical instrument.

This characteristic makes such sensors thus relatively costly to produce, because they must necessarily be applied during the component manufacturing and assembly steps; this entails an increase in the constructive complexity of the whole instrument and makes the availability of the technology conditional on the possession of know-how by the manufacturer, thus generating further costs.

Moreover, as such instruments are covered by a biocompatible coating that imparts lubricity to the instrument, the above-mentioned sensors must be produced either before the coating or after the coating, which makes the fixing thereof on the coated surface more difficult and thus costly. Furthermore, there is a risk that subsequent processing will impair the functioning of the sensor or that, on the contrary, an application of the sensors before the processing will be very complex.

In addition, it is impossible to flexibly and thus separately manage the “shelf life” of the surgical instrument and that of the bend sensor.

In short, the proposed solutions pose serious drawbacks tied to a difficulty of construction and the complexity of the structural characteristics of the sensors; this inevitably affects the costs and manufacturing times.

There is a strong need to improve the interaction between a surgical instrument and images used to guide surgical interventions, for example those produced through ultrasound scanning, in order to overcome the problems described.

The general object of the present invention is to provide a control of a surgical instrument that overcomes the problems of the prior art.

A specific object of the present invention is to provide a control of a surgical instrument that simplifies the interaction between the surgical instrument and ultrasound images produced during the practical use of the instrument.

Another object of the present invention is to provide a control of a surgical instrument that simplifies the use of the instrument by medical personnel.

A further object of the present invention is to provide a control of a surgical instrument that makes it possible to reduce the surgical risks for a patient. SUMMARY OF THE INVENTION

In a first aspect of the invention, these and other objects are achieved by a support apparatus according to the appended claim 1 .

Advantageous aspects are shown in the dependent claims 2 to 5.

In a second aspect of the invention, these and other objects are achieved by a device for detecting the current position of a surgical instrument according to the appended claim 6.

Advantageous aspects are shown in the dependent claim 7.

In a third aspect of the invention, these and other objects are achieved by a functional assembly according to the appended claim 8.

Advantageous aspects are shown in the dependent claims 9 to 13.

In a fourth aspect of the invention, these and other objects are achieved by a method for detecting the current position of a surgical instrument according to the appended claim 14.

Advantageous aspects are shown in the dependent claim 15.

The invention as described allows an efficient interaction between a surgical instrument and instruments which generate images for guiding surgical interventions, for example an ultrasound scan, in order to overcome the problems described while achieving the following technical effects:

- it simplifies the interaction between the instrument and the ultrasound images produced;

- it is simple for medical personnel to use;

- it causes minimal risk for the patient.

The aforementioned technical effects/advantages and other technical effects/advantages of the invention will emerge in greater detail from the description, provided below, of an example embodiment given by way of non-limiting illustration with reference to the appended drawings. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 represents a perspective view of a support apparatus according to the invention.

Figure 2 represents a front view of a support apparatus according to the invention.

Figure 3 shows a general block diagram of a device for detecting the current position of a surgical instrument comprising the support apparatus in figures 1 and 2, according to the invention.

Figure 4 represents a front perspective view of a functional assembly comprising the support apparatus in figures 1 and 2 and the device in figure 3, according to the invention.

Figure 5 represents a rear perspective view of a functional assembly comprising the support apparatus in figures 1 and 2 and the device in figure 3, according to the invention.

DETAILED DESCRIPTION

The invention regards in general a functional assembly, in particular a displacement sensor, through which a bending is derived, applied externally (around) the proximal part of a needle, so as to estimate the bending thereof on the basis of the force detected by the fulcrum of the lever composed of the needle itself.

Even more in particular, the invention regards a “collar’Vsupport made of deformable material, which has some proximity sensors, in particular pressure or bend sensors, associated with it, in particular fixed to it. The deformable support is then radially surrounded by a rigid outer support, so as to render the inner support deformable only in the point of contact, thus avoiding phenomena of stretching thereof. The collar is then anchored to the handle or to other support structures so as not to come into contact with the shaft of the needle in the “rest” condition.

One example is a rubber collar on which strain gauges are radially applied; the latter undergo strain due to the contact and the pressure exerted by the needle when it is bent as a result of the force applied to it. The repeatability of the measurement is given by the repeatability of the deformation of the material of the collar.

Other sensors make use of optical fibre segments that are arranged radially around the needle and fixed onto the collar and, once compressed by the needle, detect a change in the passage of light.

Other sensors provide for the use of load cells with the same principle.

The operation may be schematically illustrated as follows.

In particular, in a first aspect of the invention, with reference to figure 1 , a support apparatus 1 according to the invention is shown.

The apparatus 1 comprises a support made of deformable material 10 which defines a geometric reference axis X.

In one embodiment, the support made of deformable material 10 comprises a collar structured so as to transversely surround a surgical instrument, in particular a needle.

The apparatus 1 further comprises a support made of rigid material 30 provided externally and in contact with the support made of deformable material 10 so as to prevent an outward deformation thereof.

With reference to figures 1 and 2, the apparatus further comprises a plurality of proximity sensors Spi (i=1..n), in particular at least 3 proximity sensors, fixed to the support 10 circumferentially around the geometric reference axis X.

According to the invention, the proximity sensors Spi; i=1 ..n are adapted to generate reference signals Si; i=1..n defined as a function of a detected radial reference RRADJ.

In particular, the proximity sensors Spi; i=1..n are fixed circumferentially to the deformable support 10 and reciprocally angularly offset (ai; i=1..n) so that a different detected radial reference RRAD brings about the generation of different reference signals (Si; i=1 ..n).

In one embodiment of the invention, the proximity sensors (Spi; i=1..n) comprise capacitive sensors.

In one embodiment of the invention, the proximity sensors (Spi; i=1..n) comprise pressure sensors; thus the detectable reference signals (Si; i=1..n) are pressure signals and the detectable radial reference RRADJ is a detected radial pressure.

In one embodiment of the invention, the pressure sensors comprise an optical fibre.

With reference to figure 3, in a second aspect of the invention, a device for detecting the current position POSACT of a surgical instrument 100 is schematically shown.

The device according to the invention comprises the described support apparatus 1 , which is configured to support the surgical instrument 100. According to the invention, the described support apparatus 1 is configured to support the surgical instrument 100 in such a way that the geometric reference axis X of the apparatus coincides with a longitudinal axis X1 of the surgical instrument 100.

The device further comprises a processing unit 50 in data communication with the apparatus 1.

In general it should be noted that, in the present context and in the subsequent claims, the processing unit 50 is presented as divided into distinct functional modules (memory modules or operating modules) for the sole purpose of describing the functions thereof in a clear and complete manner.

In reality the processing unit can, in one case, consist of a single electronic device, suitably programmed to perform the functions described, and the different modules can correspond to hardware entities and/or routine software forming part of the programmed device.

Alternatively, or in addition, said functions can be carried out by a plurality of electronic devices over which the aforesaid functional modules can be distributed.

The processing unit 50 can further rely on one or more processors to execute the instructions contained in the memory modules.

The aforesaid functional modules can also be distributed over various local or remote computers based on the architecture of the network they reside in.

In the specific context of the invention, the processing unit 50 is configured to control the operation of the detection device.

The processing unit 50 is configured to receive, as input, characteristic dimensions DIM-ioo of the surgical instrument 100 and a predefined deformation law LAWDEF of the surgical instrument 100.

The deformation law LAWDEF of the surgical instrument 100 is defined as a function of the characteristic dimensions, in particular at least the length, calibre and material of the surgical instrument and, if available, experimental tests.

The processing unit 50 is further configured to receive, as input, a positional mapping MSpi of the proximity sensors Spi; (i=1..n) of the apparatus 1 relative to the surgical instrument (100).

In particular, the positional mapping MSpi of the proximity sensors Spi; is defined on the basis of respective angular offsets ai (i=1..n) relative to the deformable support (10).

The processing unit 50 is further configured to calculate a current entity of deviation ADXACT of the surgical instrument 100 from the geometric reference axis X on the basis of the reference signals Si; i=1..n generated by the proximity sensors Spi; i=1..n mapped on the basis of the positional mapping MSpi.

In other words, again with reference to figure 3, the processing unit comprises a first calculation module 51 configured to receive, as input, the reference signals Si (i=1..n) and the positional mapping MSpi, and configured to calculate the current entity of deviation ADXACT of the surgical instrument 100 from the geometric reference axis X.

The processing unit 50 is further configured to calculate a current position POSact of a portion 101 of the surgical instrument 100 on the basis of the characteristic dimensions DIM-ioo, the current entity of deviation ADXACT and the deformation law LAWDEF. In other words, again with reference to figure 3, the processing unit comprises a second calculation module 52 configured to receive, as input, the characteristic dimensions DIM-ioo, the current entity of deviation ADXACT and the deformation law LAWDEF, and to calculate the current position POSact of the portion 101 of the surgical instrument 100.

A functional assembly 200 is described with reference to figures 4 and 5, as a third aspect of the invention.

The functional assembly 200 comprises the surgical instrument 100 and the device for detecting the current position POSACT of the surgical instrument 100.

The functional assembly 200 comprises a grip 40 designed to engage with the surgical instrument 100 so as to enable a movement thereof by an operator.

The main axis of extension X1 of the surgical instrument 100, in a non- deviated condition, substantially coincides with the geometric reference axis X and the apparatus 1 is fitted over the surgical instrument 100 transversely to the main axis of extension X1.

According to the invention, the apparatus 1 is coupled to the surgical instrument 100 so that a variation in an operating position POS of the surgical instrument 100 brings about the generation of corresponding reference signals Si (i=1..n) by the proximity sensors Spi (i=1..n).

The device for detecting the current position POSACT is designed to detect the current position of a portion 101 of the surgical instrument 100.

In particular, the portion 101 comprises one end of the surgical instrument 100, more in particular a tip.

In a preferred embodiment of the invention, the surgical instrument 100 comprises a needle.

Alternatively, the surgical instrument comprises a probe or an applicator. According to the invention, a software application must carry out a calibration in relation to the resistance exerted by the needle by virtue of the force that is released at the collar/fulcrum of the support apparatus 1 : every force detected by the sensors corresponds to an amount of bending measurable with an angle.

When a sensor detects the contact and the intensity thereof, a software application determines the radial position of the contact, locating it on the basis of the location of the strain gauge(s) concerned.

Based on what has been said, it is thus possible to know, at every moment, the angle and the direction of bending of the needle, that is, the “deviation” of the needle. By combining the deviation with the length of the needle, a software application calculates, in real time, a region in space wherein the position of the tip can be traced.

In a fourth aspect, the invention describes a method for detecting the current position POSACT of a surgical instrument 100, comprising the steps of providing the support apparatus 1 ; placing the surgical instrument 100 in such a way that the geometric reference axis X in the apparatus 1 coincides with a longitudinal axis of the surgical instrument 100, causing the surgical instrument 100 to be supported by the apparatus 1 in such a way that the surgical instrument 100 is in contact with the at least 3 proximity sensors Spi (i=1..n) of the apparatus 1 ; by means of a processing unit 50, performing the steps of: receiving, as input:

- characteristic dimensions DIM-ioo of the surgical instrument

100;

- a predefined deformation law LAWDEF of the surgical instrument 100;

- a positional mapping MSpi of the proximity sensors Spi (i=1..n) of the apparatus 1 relative to the surgical instrument 100; calculating a current entity of deviation ADXACT of the surgical instrument 100 from the geometric reference axis X as a function of the pressure signals Si (i=1..n) generated by the pressure sensors Spi (i=1..n) mapped on the basis of the positional mapping MSpi. calculating a current position POSact of a portion 101 of the surgical instrument 100 as a function of the characteristic dimensions DIM-ioo, of the current entity of deviation ADXACT and of the deformation dynamics LAWDEF.

In particular, the calculation of the positional mapping MSpi of the proximity sensors Spi (i=1..n) is made on the basis of respective angular offsets ai (i=1..n) relative to the deformable support 10 of the apparatus 1. A control of a surgical instrument has been described in relation to the multiple functions thereof and interacting components.

The invention as described enables an efficient interaction between a surgical instrument and instruments which generate images to guide surgical interventions, for example an ultrasound scan, thereby achieving the following technical effects: - it simplifies the interaction between the instrument and the ultrasound images produced;

- it is simple for medical personnel to use;

- it causes minimal risk for the patient.