Sensor device

Abstract

A sensor device for detecting one or more parameters at an in vivo location within a subject is provided, the sensor device comprising: a housing; a connector for providing signal data relating to the

Description

[0001] SENSOR DEVICE

[0002] The present invention relates to a sensor device. The sensor device finds advantageous use in detecting parameters, such as temperature and fluid pressure, at in vivo locations within a subject. The present invention also relates to the use of the sensor device.

[0003] The measurement of various parameters, such as temperature and fluid pressure, at sites within the human or animal body is required in a range of different procedures. In many situations, it is acceptable to obtain measurements of such parameters in a non-invasive manner, externally of the subject. However, there are a number of situations where it would be advantageous to obtain measurements to monitor different parameters directly at an in vivo location within the subject. One such example is during endourological procedures, where the accurate monitoring of conditions prevailing within the kidney of the subject would be most advantageous.

[0004] The use of lasers in endourological procedures is now well established. A recent review of the application of lasers in endourology is provided by Brewin, A.E. and Somani, B.K., ‘What is new in lasers for endourology: looking into the future’, Urology News, Volume 25, No. 2. One important application of lasers is the treatment of kidney stones.

[0005] Kidney stones are a common condition, with the number of patients developing kidney stones increasing. Urolithiasis, that is the presence of stones in any part of the urinary tract, including the kidneys, ureter, bladder and urethra, is a chronic condition that requires treatment. Techniques for treating kidney stones include shockwave lithotripsy (SWL), ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL). The use of URS and PCNL has increased in recent years, with a decline in the use of SWL and invasive surgery.

[0006] In the case of URS, an ureteroscope is introduced into the affected region. The ureteroscope is used to visualise the kidney stones and provide a conduit for treatment of the stones by means of a laser. During URS, it is common practice to provide irrigation, typically saline irrigation, to expand the ureteral lumen. This permits visualisation of the renal pelvis and calices. In addition, expansion also facilitates the insertion and navigation of the ureteroscope through the renal system. Irrigation to expand the ureteral lumen requires an increase in the fluid pressure within the ureter and the kidneys. Typically, intra-renal pressures range from 10 to 20 cm H2O (0.01 to 0.02 Bar). This pressure is elevated during irrigation and can rise to dangerous levels of from 100 to 300 cm H2O (0.1 to 0.3 Bar).

[0007] Irrigation may be provided using a number of techniques. Perhaps the simplest is gravity irrigation, where the irrigation fluid is provided to the patient from a reservoir of fluid held at a height above the patient. However, this technique provides little or no control over the irrigation, in particular the increase in fluid delivery or pressure. As a result, gravity irrigation is typically used to apply irrigation fluid at lower pressures, in order to ensure intra-pelvic pressures are kept low and within safe limits. Alternatively, irrigation may be provided by means of a manual pump to provide the irrigation fluid at an elevated pressure. However, it can be difficult to control the increase in intra-pelvic pressure and pressures as high as 250 cm H2O (0.25 Bar) have been recorded. These high pressures result in an increased risk of complications from the procedure, especially bleeding, sepsis and even death. More recently, advanced irrigation systems have been developed, which provide for improved control of the fluid flow and intra-luminal pressures during URS. An example of a commercially available irrigation system is the Thermedx FluidSmart system.

[0008] Generally, increases in intra-renal fluid pressure up to 20 cm H2O (0.02 Bar) provide a safe working range with a lower risk of complications. Increases in intrarenal pressure above this value significantly increase the risk of post-operative complications. Such complications include bleeding, perirenal collection, sepsis and death. The techniques of conducting URS procedures and the attendant risks are discussed by Neto, A.C.L., et al., ‘Intra-renal pressure and temperature during ureteroscopy: Does it matter?’, IB JU, Vol. 47(2), March - April 2021 , pages 436 to During URS, a laser is used to break the kidney stones into smaller fragments, which can be more easily removed and / or may pass out of the body in the urine. The laser treatment releases a significant amount of energy in the form of heat, which in turn raises temperatures within the renal system of the patient, with a risk of damage to the surrounding tissue and organs. The effects of increased temperatures during endourological procedures are discussed by Rice, P., et al., ‘Generated temperatures and thermal laser damage during upper tract endourological procedures using the holmium:yttrium-aluminium-gamet (Ho:YAG) laser: a systematic review of experimental studies’, World Journal of Urology, (2022) 40: pages 1981 to 1992. It is reported that preclinical and clinical studies have shown that temperatures ranging from 41 to 47°C result in a direct cellular destruction. Temperatures exceeding 43°C lead to an exponentially increased cytotoxic effect. The thermal cytotoxic effects are not limited to the peak temperature achieved during laser treatment. As a result, the thermal dose t43 has been defined as the thermal energy required to maintain a temperature of 43°C for 120 minutes. The t43 parameter may be used to identify adverse effects of the laser treatment, with a t43 of greater than 120 minutes giving rise to a high risk of thermal tissue injury.

[0009] Rice, P., et al. report that irrigation can help to reduce temperatures during URS, with the irrigation fluid acting as a heat sink to remove thermal energy from the site of treatment. Irrigation can help to lengthen the time required to reach the threshold of thermal damage, in turn reducing the treatment time. An examination of data on temperatures produced during laser lithotripsy and suggested strategies for maintaining lower temperatures during endourological procedures is provided by Tokas, T., et al., ‘Temperature change during laser upper-tract endourological procedures: current evidence and future perspective’, Current Opinion Urology, 2022, March, pages 108 to 115.

[0010] With both pressure and temperature within the renal system of the patient being significant factors during URS, there is a need for improved techniques and apparatus to carry out URS procedures with a reduced risk of complications arising post-treatment. In particular, there is a need for an improved method and apparatus for carrying out URS procedures which reduce or prevent the occurrence of excessive intra-renal pressures and temperatures. One way to achieve this improvement would be to provide a sensor that may be deployed in vivo into the renal system of the subject to detect parameters, such as temperature and pressure of fluid at key sites within the renal system during the URS procedure.

[0011] One type of known sensor for measuring fluid pressure employs a conduit, such as a catheter, which is inserted into the subject to the location where the pressure is to be measured. The lumen of the catheter fills with fluid from the location entering the open distal end of the catheter. A pressure sensor, such as a transducer or manometer, is located at the proximal end of the catheter outside of the subject. Changes in the fluid pressure within the catheter and, hence, at the in vivo site in the subject can be measured.

[0012] US 4,901 ,731 discloses a single sensor pressure differential device. The device comprises a single pressure transducer having a deformable member mounted to a housing. A conduit extends within the housing with one end opening at a location spaced from the transducer and the other end opening adjacent the deformable member. In use, the housing is located at a site within the body of the subject. The outer surface of the deformable member is exposed to fluid at the site and flexes in response to the pressure differential across the deformable member. The member is provided with strain gauges to generate a signal in response to flexing of the deformable member. In a preferred embodiment, the device is incorporated into an angioplasty-type catheter having a dilation balloon mounted to the housing.

[0013] US 7,025,724 discloses a guidewire having a sensor for detecting NO and / or superoxide levels. The guidewire finds use in the in vivo analysis of vascular health.

[0014] WO 2007 / 002225 proposes an implantable wireless sensor for the measurement of pressure at in vivo locations. The sensor comprises a capacitative circuit and an inductor coil connected to form an LC or resonant circuit. The LC circuit is encapsulated within an electrically insulating housing. Changes in parameters at the location are measured by corresponding changes in an electrical property of the circuit, in particular changes in the capacitance of the LC circuit as a result of deflections of a portion of the housing moving a plate of the capacitor. The sensor is proposed for use to measure pressure in the heart or vasculature of the subject.

[0015] CN 211484618U discloses an in vivo pressure measuring device. The device comprises a sealed shell, a circuit board and a gas pressure sensor disposed within the shell. The sealed shell is filled with gas. A support frame is fixedly connected to the inner side wall of the sealed shell for mounting the circuit board. The gas pressure sensor is mounted on the circuit board and is used for monitoring the change of the gas pressure within the shell.

[0016] US 2015 / 305633 discloses a catheter having a pressure sensor for sensing the pressure of blood at an in vivo location.

[0017] US 2016 / 029960 concerns a range of surgical procedures. A guidewire is disclosed having a range of sensors for monitoring a range of physiological parameters from within the body.

[0018] A kit for coronary treatment is disclosed in US 2016 / 120415. The kit comprises a guidewire having a pressure sensor for sensing pressure within the vasculature of a patient.

[0019] US 2017 / 325673 concerns a monitoring system for endoscopic treatments, in particular endourological treatments. The system comprises a guidewire with at least one sensor.

[0020] US 2019 / 150758 discloses an in vivo sensor device. The device comprises a plurality of sensors for monitoring physical, chemical or electrical parameters within the body of the subject. The sensors are provided integrally with an implantable device and are responsive to externally or internally applied energy, resulting in a phase change of at least a part of the device. The phase change is monitored by imaging, such as radiography, ultrasound, magnetic resonance (MRI), radio frequency (RFI) or the like. The device may be employed to provide data regarding a range of parameters, such a volume, flowrate, temperature, pressure, electrical or biochemical parameters within the subject.

[0021] More recently, US 2021 / 0290078 proposes a pressure sensor for in vivo applications. The sensor comprises a pressure-measurement transformer and a probe connected proximally to the pressure-measurement transformer. The probe includes a catheter having a measuring tip at its distal end. The lumen of the catheter is filled with a transmission liquid. The measuring tip comprises a tubular portion having at least one opening covered by an elastic membrane. US 2021 / 0290078 indicates that the device may be used to monitor the blood pressure of a subject without the need to implant electronic components within the subject.

[0022] US 2021 / 0123819 discloses a temperature measuring device. A heat flux sensor comprises two temeparture sensors. In use, the heat flux sensor is used to obtain time-series data relating to the core temperature of the subject. Blood flow in the vicinity of the two sensors is measured by a blood flow sensor.

[0023] WO 2022 / 094239 discloses devices and methods for treating kidney stones.

[0024] Still more recently, US 2023 / 0200658 discloses an in vivo pressure measurement device. The device comprises a light source configured to output test light, an optical fibre comprising at least in part a sensor optical fibre to transmit the test light, and a light receiving unit for receiving test light transmitted through the sensor optical fibre. In use, a catheter is inserted into the subject. Pressure from blood within the subject is propagated to a second fluid, such as a saline solution. The sensor optical fibre contacts the second fluid. Changes in the pressure within the second fluid change the transmission losses of light within the sensor optical fibre, which in turn are measured to determine the blood pressure of the subject. There is a need for an improved sensor device for measuring parameters at an in vivo location within a subject. It would be advantageous if the sensor device could be of a simple design and deployed within the subject in a simple procedure. It would be advantageous if the sensor device could allow the parameters to be measured accurately. It would also be advantageous if the sensor device could be robust and not easily damaged, for example during the procedure to insert or remove the device from an in vivo location within a subject.

[0025] According to the present invention there is provided a sensor device for detecting one or more parameters at an in vivo location within a subject, the sensor device comprising: a housing; a connector for providing signal data relating to the one or more parameters; a conduit having a proximal and a distal end, the conduit extending at its proximal end from the housing, wherein the conduit comprises a cavity in the distal end portion of the conduit, the conduit having an opening in the distal end portion communicating the cavity with the exterior of the conduit; a sensor assembly disposed in the cavity in the distal end portion of the conduit comprising one or more sensors operable to sense one or more parameters in the surroundings of the distal end portion of the conduit, in use the sensor assembly being exposed to fluid entering the cavity through the opening in the distal end of the conduit; and a cable connected at its distal end to the sensor assembly and at its proximal end to the connector for carrying electrical signals from the sensor assembly to the connector. The sensor device comprises a housing. The housing is disposed at the proximal end of the sensor device. The housing may be considered to have a distal end and a proximal end.

[0026] The housing may be formed from any suitable material. Suitable medical grade materials, such as medical grade plastics are known in the art and are commercially available. The housing may be formed in any suitable manner applicable to the materials of construction. For example, the housing may be formed by moulding. The housing may be formed as a single piece or, alternatively, from a plurality of housing components. For example, the housing may be a two- piece assembly, such as formed from two moulded housing halves. The housing components may be connected together by any suitable means, for example by adhesive, mechanical connections or welding, such as sonic welding in the case of a plastic housing.

[0027] The sensor device further comprises a connector. In use, the connector provides signals relating to the one or more parameters sensed by the sensor assembly. More particularly, the connector allows the sensor device to be connected to other components to receive signals, such as electrical and / or wireless signals, from the sensor device regarding one or more parameters sensed by the sensor assembly at the in vivo site within the subject. The connector is preferably disposed within the housing, more preferably at the proximal end of the housing. The housing may comprise an opening to allow access to the connector, for example to connect one or more cables to the sensor device for receiving electrical signal data.

[0028] The connector may be arranged to provide a corded or wired connection to another component. Suitable connectors for connecting the sensor device to other components and allow the transfer of signals, such as electrical signals are known in the art and are commercially available.

[0029] The sensor device further comprises a conduit. The conduit is elongate and has a proximal end and a distal end. The conduit extends at its proximal end from the housing. Preferably, the proximal end portion of the conduit is engaged with the housing, thereby retaining the conduit. The conduit may be releasably connected at its proximal end to the housing. More preferably, the proximal end of the conduit is fixedly engaged with the housing. For example, in one preferred embodiment, the proximal end portion of the conduit is held within the housing, for example by the housing engaging with the outer surface of the conduit, such as by a clamping action exerted on the outer surface of the conduit by the housing. In one embodiment, the housing comprises an open cavity, with the proximal end of the conduit extending into an opening of the cavity. The housing may be provided with one or more members within the cavity to engage with the outer surface of the conduit. In one preferred embodiment, the housing comprises one or more pairs of opposing members, the members in each pair engaging with opposing sides of the outer surface of the conduit to grip and / or clamp the conduit and hold the proximal end of the conduit.

[0030] The distal end of the conduit is open and comprises one or more openings in the distal end portion of the conduit. A sensor assembly is disposed in the cavity in the distal end portion of the conduit, as described in more detail hereinafter. In a preferred embodiment, the conduit has a lumen extending along at least part, preferably all of the length of the conduit.

[0031] The conduit houses one or more cables or wires, which connect the sensor assembly in the distal end portion of the conduit to the connector, as described in more detail hereinbelow. Preferably, the conduit is generally tubular in structure at least at its distal end portion and comprises a central elongate cavity, such as a lumen. The portion of the conduit proximal of the distal end portion may be solid. More preferably, the portion of the conduit proximal of the distal end portion is also tubular, more preferably still with the conduit being tubular and having a lumen extending along its entire length.

[0032] The conduit is most preferably flexible, allowing the distal end of the conduit to be located at the in vivo location being targeted with ease. Suitable materials for forming the conduit are known in the art, with polymeric materials being especially preferred. Suitable medical grade polymer materials for forming the conduit are known in the art. Suitable materials for forming the conduit include those known in the art for forming catheters. Suitable materials include polyvinyl chloride (PVC), synthetic or natural rubber or latex, silicone and polytetrafluoroethylene (PTFE).

[0033] The conduit may be substantially transparent or translucent. The conduit is preferably coloured, more preferably a colour other than red, to allow for identification of the conduit and its properties, for example one or more of the sensors it contains and the size of the conduit and the sensor assembly.

[0034] Preferably, the conduit comprises means allowing the location of the conduit within the subject to be determined, so as to aid proper placement of the sensor assembly at the in vivo location. In one preferred embodiment, the conduit is formed from a material comprising one or more components that allow the conduit to be located within the subject, for example by scanning, such as with x-rays. In one embodiment, the material of the conduit comprises one or more compounds that fluoresce when exposed to x-rays, thereby allowing the conduit to be identified and its location determined.

[0035] The conduit is of a size to accommodate the sensor assembly and allow the conduit to be deployed to the in vivo location within the subject.

[0036] The conduit may have an outer diameter of up to 4,000 micron, preferably up to 3,500 micron. Preferably, the conduit has an outer diameter up to 3,000 micron, preferably up to 2,800 micron, more preferably up to 2,600 micron, still more preferably up to 2,500 micron, more preferably still up to 2,400 micron, especially up to 2,300, more especially up to 2,200 micron, more especially still up to 2,100 micron, still more especially up to 2,000 micron. The conduit may have an outer diameter of from 250 micron, preferably from 300 micron. Preferably, the conduit has an outer diameter of from 350 micron, preferably from 400 micron, more preferably from 450 micron, still more preferably from 500 micron, more preferably still 550 micron, especially from 600, more especially from 650 micron, more especially still from 700 micron, still more especially from 700 micron. The conduit may have an outer diameter of from 300 to 3,000 micron, preferably from 400 to 2,600, more preferably from 450 to 2,500, still more preferably from 500 to 2,400, more preferably still from 550 to 2,300, especially from 600 to 2,200, more especially from 650 to 2,100, still more especially from 700 to 2,000. In one preferred embodiment, the conduit has an outer diameter of from 750 to 2,000 micron.

[0037] The conduit may have an inner diameter of up to 2,500 micron, preferably up to 2,200 micron. Preferably, the conduit has an inner diameter up to 2,000 micron, preferably up to 1 ,800 micron, more preferably up to 1 ,600 micron, still more preferably up to 1 ,500 micron, more preferably still up to 1 ,400 micron, especially up to 1 ,300, more especially up to 1 ,200 micron, more especially still up to 1 , 100 micron, still more especially up to 1 ,000 micron. The conduit may have an inner diameter of from 250 micron, preferably from 275 micron, more preferably from 300 micron, still more preferably from 350 micron, more preferably still 375 micron, especially from 400, more especially from 450 micron, more especially still from 475 micron, still more especially from 500 micron. The conduit may have an inner diameter of from 300 to 2,000 micron, preferably from 325 to 1 ,600, more preferably from 350 to 1 ,500, still more preferably from 375 to 1 ,400, more preferably still from 400 to 1 ,300, especially from 425 to 1 ,200, more especially from 450 to 1 ,100, still more especially from 475 to 1 ,000. In one preferred embodiment, the conduit has an inner diameter of from 500 to 1 ,000 micron.

[0038] In one preferred embodiment, the conduit is a 6 French tube (2 mm outer diameter) or smaller, more preferably a 5 French tube (1 .667 mm outer diameter) or smaller, still more preferably a 4 French tube (1 .333 mm outer diameter) or smaller, more preferably still a 3 French tube (1 mm outer diameter) or smaller, such as a 2 French tube (0.67 mm outer diameter) or 1 French tube (0.33 mm outer diameter). A conduit having a size from 1 French to 6 French is preferred for many embodiments, more preferably from 2 French to 5 French, still more preferably from 3 French to 4 French. A3 French tube has been found to be particularly suitable for many embodiments.

[0039] The conduit may have any suitable length to allow the distal end of the conduit be located at the in vivo location being targeted by the sensor assembly and the proximal end of the conduit and the housing to be outside the subject. The conduit may have a length of up to 3 m, preferably up to 2.75 m, more preferably up to 2.5 m, still more preferably up to 2.4 m, more preferably still up to 2.3 m, especially up to 2.2 m, more especially up to 2.1 m, still more especially up to 2 m. The conduit may have a length of from 0.15 m, preferably from 0.2 m, more preferably from 0.25 m, still more preferably 0.3 m, more preferably still from 0.35 m, especially from 0.4 m, more especially from 0.45 m, still more especially from 0.5 m. The conduit may have a length of from 0.15 to 3 m, preferably from 0.2 to 2.75 m, more preferably from 0.25 to 2.5 m, still more preferably from 0.3 to 2.25 m, more preferably still from 0.35 to 2.2 m, especially from 0.4 to 2.15 m, more especially from 0.45 to 2.1 m. In one preferred embodiment, the conduit has a length of from 0.5 to 2 m.

[0040] As noted above, the distal end portion of the conduit comprises a cavity. The cavity may be a lumen within a tubular distal end portion of the conduit. The cavity contains a sensor assembly, as described in more detail hereinbelow. The distal end portion of the conduit comprises one or more openings therein, allowing the cavity to communicate with the surroundings of the distal end portion. In use, fluid enters the cavity through the one or more openings and contacts the sensor assembly. The conduit may comprise an opening at its distal end, that is an opening in the distal end of the conduit. Alternatively or in addition, the conduit may comprise one or more openings in its wall, preferably spaced from the distal end of the conduit. Each such opening extends laterally through the wall from the outer surface of the conduit to the cavity within the distal end portion, for example radially through the wall. Each such opening is preferably spaced from the distal end of the conduit. In one embodiment, the distal end portion of the conduit comprises a single opening, preferably in the distal end of the conduit. In an alternative embodiment, the distal end portion of the conduit comprises a plurality of openings, for example an opening in the distal end of the conduit and one or more openings extending laterally through the wall of the conduit. Alternatively, the distal end of the conduit may be closed and the conduit comprise one or more openings extending laterally through the wall of the conduit.

[0041] The sensor device further comprises a sensor assembly. The sensor assembly is disposed within the distal end portion of the conduit, more preferably within a cavity or lumen within the distal end portion of the conduit. As noted above, the distal end portion of the conduit comprises one or more openings therein, allowing fluid surrounding the distal end portion of the conduit to enter the cavity or lumen within the conduit. In this way, the sensor assembly is exposed to fluid during use.

[0042] The sensor assembly may be disposed within the conduit adjacent an opening in the distal end portion of the conduit, for example at the distal end of the conduit. Preferably, the sensor assembly does not protrude out of the conduit, for example beyond the distal end of the conduit. In this way, the sensor assembly is exposed to fluid surrounding the distal end of the conduit, while also being protected within the conduit. More preferably, the sensor assembly is disposed within the cavity or lumen at the distal end portion of the conduit and spaced from the distal end of the conduit. Preferably, the sensor assembly is spaced from the one or more openings in the distal end portion of the conduit, again to better protect the sensor assembly.

[0043] In one embodiment, the sensor assembly is disposed within the lumen of the tubular distal end portion of the conduit, preferably spaced from the distal end of the conduit, which may comprise an opening therein.

[0044] The sensor assembly is preferably spaced from the or each opening in the distal end portion of the conduit and / or the distal end of the conduit, as noted above. The sensor assembly may be spaced any suitable distance from the one or more openings and / or the distal end of the conduit that allows the sensor assembly to be protected within the conduit while still allowing the sensor assembly to be exposed to fluid entering the cavity within the conduit from the surroundings. The sensor assembly may be spaced from the or each opening and / or the distal end of the conduit by up to 40 mm, preferably up to 35 mm, more preferably up to 30 mm, still more preferably up to 25 mm, more preferably still up to 20 mm, especially up to 15 mm. The sensor assembly may be spaced from the or each opening and / or the distal end of the conduit by from 0.5 mm, preferably from 1 mm, more preferably from 2 mm, still more preferably from 2.5 mm, more preferably still from 3 mm, especially from 3.5 mm, more especially from 4 mm, still more especially from 4.5 mm. The sensor assembly may be spaced from the or each opening and / or the distal end of the conduit by from 0.5 to 40 mm, preferably from 1 to 35 mm, more preferably from 2 to 30 mm, still more preferably from 2.5 to 25 mm, more preferably still from 3 to 20 mm, especially from 3.5 to 18 mm, more especially from 4 to 16 mm. In one preferred embodiment, the sensor assembly is spaced from the or each opening and / or the distal end of the conduit by from 5 to 15 mm. In embodiments in which the conduit comprises a plurality of openings at different distances from the distal end of the conduit, the aforementioned spacings may be from the proximal-most opening.

[0045] In one preferred embodiment, the conduit comprises a single opening in its distal end portion at its distal end. In this embodiment, the aforementioned distances are therefore the distance the sensor assembly is spaced from the distal end of the conduit. In one preferred embodiment, the sensor assembly is spaced from the distal end of the conduit by from 5 to 15 mm.

[0046] The size of the sensor will be determined by factors such as the intended use of the sensor device, in particular the in vivo locations within the subject to be accessed. In this respect, the sensor device of the present invention may be used to sense one more parameters at a range of different in vivo sites within a subject. In many procedures, access to the in vivo location will be through an existing tract or vessel of the subject. Alternatively, access to the in vivo location may be obtained after an incision has been made in the subject. One particularly advantageous use of the sensor device of the present invention is for monitoring parameters within the subject during a procedure for the treatment of kidney stones. One preferred location for deploying the sensor assembly therefore is within the urinary collection system of the subject, for example the renal pelvis of the urinary collection system within the kidney or, less likely, within an individual calyx of the kidney. In such cases, the sensor assembly and the conduit are therefore preferably of a size to allow them to be inserted and located within urinary collection system, such as in the renal pelvis.

[0047] The sensor assembly may have any suitable width as determined by the in vivo location to be accessed and targeted. Preferably, the sensor assembly has a width or diameter that is less than 4 mm, more preferably less than 3 mm, still more preferably less than 2 mm, more preferably still less than 1 mm. It is particularly preferred for many applications, such as for accessing the urinary collection system close to or within the kidneys, that the sensor assembly has a width or diameter that is less than 0.75 mm, preferably less than 0.5 mm, more preferably less than 0.4 mm, still more preferably less than 0.3 mm, more preferably still less than 0.25 mm. In this respect, the ‘width’ or ‘diameter’ of the sensor assembly is the dimension of the sensor that extends laterally across the sensor assembly in the orientation in which the sensor assembly is located within the conduit. A sensor assembly having a width of 0.2 to 0.3 mm is preferred for many embodiments, for example a width of 275 microns (0.275 mm).

[0048] In many applications, the length of the sensor assembly is less critical. In this respect, the ‘length’ of the sensor assembly is a reference to the dimension of the sensor assembly longitudinally along the sensor assembly in the orientation in which the sensor assembly is located within the conduit. Preferably, the sensor assembly has a length that is less than 6 mm, more preferably less than 5 mm, still more preferably less than 4 mm, more preferably still less than 3 mm. It is particularly preferred for many applications, such as for accessing the urinary collection system close to or within the kidneys, that the sensor assembly has a length that is less than 2.5 mm, preferably less than 2 mm, more preferably less than 1.75 mm, still more preferably less than 1.5 mm, more preferably still less than 1.25 mm, especially 1 mm or less. A sensor assembly having a length of from 0.5 to 1 mm is preferred for many embodiments.

[0049] In one preferred embodiment, the sensor has a width of about 275 microns and is housed within a 3 French tube (1 mm outer diameter, 0.5 mm inner diameter).

[0050] The sensor assembly comprises one or more sensors. Each sensor is operable to detect a parameter of the conditions prevailing at the location of the distal end of the conduit during use of the sensor device. Parameters that may be detected include pressure of the fluid and temperature.

[0051] In one preferred embodiment the sensor assembly comprises one or more sensors operable to sense fluid pressure and temperature at the in vivo location within the subject. The sensor assembly may comprise a plurality of sensors to detect fluid pressure and temperature, for example one or more pressure sensors and one or more temperature sensors. Alternatively, one or more combined pressure / temperature sensors may be employed. In one embodiment, the one or more combined pressure / temperature sensors may be employed together with one or more fluid pressure sensors and / or one or more temperature sensors. In this way, the sensor assembly may be provided with redundancy, to accommodate the failure or improper operation of one sensor.

[0052] Suitable technology for the one or more sensors of the sensor assembly is known in the art. In one preferred embodiment, Micro Electro Mechanical Systems (MEMS) sensors are employed. These sensors offer the advantage of having a small size that can be accommodated at a range of in vivo locations within the subject, such as within the urinary collection system of the subject. MEMS sensors also have the advantage of a low power consumption. Suitable MEMS sensors are known in the art and are commercially available, for example the SMI Intrasense range of sensors available from TE Connectivity. The SMI Intrasense sensors rely on MEMS technology and can be configured to sense both pressure and temperature. Suitable temperature sensors are also available from Okazaki Manufacturing Company.

[0053] The sensor assembly comprises connections for connecting to one or more wires of a cable, allowing electrical signals generated by the sensor assembly to be transmitted and allowing the sensor assembly to be provided with electrical power, as may be required. The number of connections will depend upon the requirements of the sensor assembly regarding transmitting electrical signals and receiving electrical power. For example, the sensor assembly may comprise 2, 3, 4, 5, 6 or more connections, preferably from 2 to 5 connections.

[0054] In one embodiment, the sensor assembly comprises 3 connections arranged on a pitch of from 30 to 150 microns, more preferably from 50 to 100 microns. In use, 2 of the 3 connections are used to receive electrical power (+ve and -ve). The third connection is used to transmit electrical signals generated by the sensor assembly.

[0055] The sensor assembly may comprise a parallel bus for transmitting electrical signals or, more preferably a serial bus.

[0056] The sensor device further comprises a cable. The sensor assembly is connected to the cable for transmitting electrical signals generated by the or each sensor in the sensor assembly during use. The cable may also provide electrical power to the sensor assembly. The cable extends longitudinally within the conduit to the housing at the proximal end of the conduit. In embodiments in which the conduit is tubular and has a lumen along part or all of its length, the cable preferably extends along the lumen of the conduit. Alternatively, the conduit may be formed around the cable, for example by moulding.

[0057] The cable comprises one or more wires for transmitting electrical signals from the sensor assembly along the conduit to the housing. The cable may comprise any number of wires sufficient to transfer electrical signals generated by the sensor assembly and to provide electrical power to the sensor assembly, as required. For example, the cable may comprise 2, 3, 4, 5, 6 or more wires. In one embodiment, the cable comprises 3 wires, wherein 2 wires are for providing electrical power to the sensor assembly (+ve and -ve) and a third wire is for serial signal transmission from the sensor assembly.

[0058] In embodiments, in which the sensor assembly comprises a single sensor, able to measure one or more parameters, it may be sufficient to employ a cable having 3 wires, two being for providing electrical power and one for the serial transmission of signal data from the sensor. In embodiments in which the sensor assembly comprises a plurality of sensors, more than 3 wires may be required. For example, in embodiments where the sensor assembly comprises a first sensor for detecting a first parameter, such as pressure, and a second sensor for detecting a second parameter, such as temperature, a cable comprising 5 wires may be employed, with two or three wires being for the provision of electrical power and two or three wires for the transmission of signal data from both sensors.

[0059] The wires of the cable may have any suitable dimension. In many cases, the dimensions of the wires, and hence the cable, will be determined by the intended use of the sensor device, which in turn determines the overall size of the various components, in particular the conduit and the sensor assembly. The wires may have a diameter of from 30 to 100 microns, preferably from 35 to 90 microns, more preferably from 40 to 80 microns, still more preferably from 45 to 75 microns. In one preferred embodiment, each wire of the cable has a diameter of from 45 to 55 microns, especially about 50 microns.

[0060] As noted above, the cable is connected to the sensor assembly and extends along the conduit to the housing at the proximal end of the conduit. Preferably, the sensor device is provided with means for securing the sensor assembly and holding it in position within the conduit. For example, the sensor assembly may be held in position within the conduit by an adhesive or by one or more gripping members formed within the conduit. Alternatively and more preferably, the sensor device comprises means for securing and holding the cable, which in turn acts to locate and hold the sensor assembly in position at the distal end of the cable within the conduit. The means for securing and holding the cable preferably at least prevent the cable moving in a distal direction, thereby preventing the sensor assembly from moving towards an opening in the distal end portion of the conduit and the distal end of the conduit. Any suitable means for securing the cable may be employed. For example, in embodiments where at least part of the conduit is formed around the cable, for example by moulding, this will function to hold the cable. In one preferred embodiment, the housing is provided with means to secure a proximal end portion of the cable. In one embodiment, the housing may comprise one or more clamping members, which act on the proximal end portion of the cable and prevent movement of the cable along the conduit. More preferably, the proximal end portion of the cable is held in a convoluted pattern by a holding formation disposed within the housing. Holding the proximal end of the cable in a convoluted pattern eases and simplifies assembly and production of the sensor device, while also ensuring that the sensor assembly is held in the correct position within the distal end portion of the conduit. The holding formation may comprise one or more holding members around which the cable is wound. Alternatively or in addition, the holding formation may comprise one or more channels or grooves within the housing, in which the cable extends. The convoluted pattern may be any pattern that securely holds the cable and prevents the cable moving along the conduit. Suitable convoluted patterns include a zig-zag pattern or a helical pattern.

[0061] As noted above, the sensor device comprises a connector disposed within the housing for connecting the device to another apparatus and allowing data signals to be transmitted to the other apparatus. In one embodiment, the cable is connected directly to the connector, such that electrical signals from the sensor assembly are passed directly to another apparatus. More preferably, the cable is indirectly connected to the connector, still more preferably by means of an interface. The interface is preferably disposed within the housing. The wires of the cable are connected at their proximal ends to the interface. The interface in turn is connected to the connector.

[0062] The interface may comprise one or more components and perform one or more functions. In one embodiment, the interface comprises a serial interface for communicating with the sensor assembly, in particular for receiving serial data signals from the sensor assembly. In one embodiment, the interface comprises a calibrator, allowing the sensor assembly to be calibrated. In one embodiment, the interface comprises a power distribution component for providing electrical power to the sensor assembly via the cable. Suitable components of the interface are known in the art and are commercially available. The interface preferably comprises a printed circuit board (PCB) on which are mounted one or more of the aforementioned components.

[0063] As described above, the sensor device comprises a connector for connecting the device to an apparatus or system, in order to provide signal data from the sensor assembly. As described, the connector typically provides a cabled or wired connection by way of one or more cables. Alternatively or in addition, the sensor device may comprise a transmitter for transmitting wireless data signals. Suitable wireless transmitters are known in the art. The wireless transmitter may be comprised in the connector or the interface or be employed as a separate component, preferably disposed within the housing. Suitable wireless protocols for the transmission of wireless signal data are known in the art and include WiFi and Bluetooth.

[0064] The sensor device may comprise a power source for providing electrical power to one or more components, such as providing electrical power to the sensor assembly, to one or more components of the interface, as required, and to a wireless transmitter, if present. Suitable sources of electrical power include assemblies for storing electrical power, such as one or more batteries. Preferably, the electrical power source is located within the housing of the sensor device.

[0065] As noted hereinbefore, the sensor device of the present invention advantageously finds a wide range of uses, in particular in the sensing of one or more parameters at in vivo locations within a subject. The sensor device may therefore be employed in an apparatus for performing a wide range of procedures on a subject. Accordingly, in a further aspect, the present invention provides a system for performing a procedure on a subject, the apparatus comprising a sensor device as hereinbefore described.

[0066] As noted above, one particularly advantageous use of the sensor device of the present invention is for detecting fluid pressure and / or temperature, in particular at an in vivo location within a subject. One particularly advantageous use of the sensor device is as part of a system for controlling a laser assembly during a procedure being performed on a subject, especially an endourological procedure being conducted on a subject.

[0067] In one embodiment, the present invention provides a system for controlling a laser assembly during an endourological procedure being conducted on a subject, the system comprising: an irrigation system comprising: a fluid delivery system for delivering an irrigation fluid intra-renally to the subject from an irrigation fluid reservoir; and a control system comprising: a temperature sensor for disposing at an intra-renal location within the subject and operable to generate a temperature signal corresponding to the temperature the intra-renal location; a pressure sensor for disposing at an intra-renal location within the subject and operable to generate a pressure signal corresponding to the pressure of fluid at the intra-renal location; wherein the temperature sensor and / or the pressure sensor are comprised in a sensor device as hereinbefore described; and a control unit configured for: receiving the temperature signal and operable to vary the operation of the laser assembly when the temperature at the intrarenal location exceeds a threshold temperature; and receiving the pressure signal and controlling the operation of the pump to vary the fluid pressure at the intra-renal location.

[0068] In a still further aspect, the present invention provides a system for conducting an endourological procedure employing a laser assembly, more especially a laser lithotripsy procedure on a subject, the system comprising: a laser assembly for generating a laser beam for deploying at an in vivo location within the endourological system of the subject; a temperature sensor for disposing at an intra-renal location within the subject and operable to generate a temperature signal corresponding to the temperature the intra-renal location; an irrigation system comprising: a pressure sensor for disposing at an intra-renal location within the subject and operable to generate a pressure signal corresponding to the pressure of fluid at the intra-renal location; and a fluid delivery system for delivering an irrigation fluid intra-renally to the subject from an irrigation fluid reservoir; and a control unit configured for: receiving the temperature signal and operable to interrupt the operation of the laser assembly when the temperature at the intra-renal location exceeds a threshold temperature; and receiving the pressure signal and controlling the operation of the pump to vary the fluid pressure at the intra-renal location; wherein the pressure sensor and / or the temperature sensor are comprised in the sensor assembly of a sensor device as hereinbefore described.

[0069] In a still further aspect, the present invention provides a method of controlling an apparatus for performing a procedure on a subject, the method comprising sensing a parameter at an in vivo location within the subject and operating the apparatus in response to the sensed parameter; wherein the parameter is sensed using a sensor device as hereinbefore described.

[0070] As noted above, the sensor device is particularly advantageous when used for conducting an endourological procedure on the subject. Therefore, in a still further aspect, the present invention provides a method for controlling the operation of a laser assembly during a laser endourological procedure on a subject, the method comprising: providing a flow of the irrigation fluid to the intra-renal location within the subject; sensing the temperature at an intra-renal location within the subject; sensing the intra-renal fluid pressure within the subject; and controlling the flow of the irrigation fluid in response to the sensed intra-renal fluid pressure; comparing the sensed temperature with a threshold temperature; and in the event the sensed temperature exceeds the threshold temperature varying the operation of the laser assembly and / or the flow of irrigation fluid to the intra-renal location; wherein the pressure and temperature are sensed using a sensor device as hereinbefore described. In a further aspect, the present invention provides a system for irrigation of the renal system of a subject, the system comprising: a fluid delivery system for delivering an irrigation fluid intra-renally to the subject from an irrigation fluid reservoir; and a control system comprising: a sensor device as hereinbefore described, wherein the sensor assembly comprises a pressure sensor and is for disposing at an intra-renal location within the subject and operable to generate a pressure signal corresponding to the pressure of fluid at the intra-renal location; and a control unit for receiving the pressure signal and controlling the operation of the fluid delivery system to vary the fluid pressure at the intra-renal location.

[0071] A still further aspect of the present invention provides a method for providing an irrigation fluid to an intra-renal location within a subject during an endourological procedure, the method comprising: providing a flow of the irrigation fluid to the intra-renal location within the subject; sensing the intra-renal fluid pressure within the subject using a sensor device as hereinbefore described; and controlling the flow of the irrigation fluid in response to the sensed intra-renal fluid pressure.

[0072] In a further aspect, the present invention provides a system for operating a laser assembly during an endourological procedure being conducted on a subject, the system comprising: a control system comprising: a sensor device as hereinbefore described, wherein the sensor assembly comprises a temperature sensor and is for disposing at an intra-renal location within the subject and operable to generate a temperature signal corresponding to the temperature at the intra-renal location; and a control unit for receiving the temperature signal and operable to vary the operation of the laser assembly when the temperature at the intra-renal location exceeds a threshold temperature.

[0073] The present invention still further provides a method for controlling the operation of a laser assembly during a laser endourological procedure on a subject, the method comprising: sensing the temperature at an intra-renal location within the subject using a sensor device as hereinbefore described; comparing the sensed temperature with a threshold temperature; and in the event the sensed temperature exceeds the threshold temperature varying the operation of the laser assembly.

[0074] Embodiments of the sensor assembly of the present invention will now be described, by way of example only, having reference to the accompanying drawings, in which:

[0075] Figure 1 is a diagrammatical representation of a system for conducting a laser lithotripsy on a subject according to one embodiment of the present invention;

[0076] Figure 2 is diagrammatical representation of the components of the system of Figure 1 ;

[0077] Figure 3 is a drawing of one embodiment of the sensor device of the present invention; Figure 4 is a cross-sectional view of the distal end portion of the sensor device of Figure 3;

[0078] Figure 5 is a cross-sectional view of the proximal end portion of the sensor device of Figure 3;

[0079] Figure 6 is a cross-sectional view of the distal end portion of a sensor device according to an alternative embodiment of the present invention;

[0080] Figure 7 is a cross-section view of the proximal end portion of the sensor device according a further alternative embodiment of the present invention; and

[0081] Figure 8 is a diagrammatical view of one half of the renal system of the subject with a sensor device of the present invention in location.

[0082] Turning first to Figure 1 , there is shown a representation of a subject 2 undergoing an endourological procedure, in particular laser lithotripsy for the treatment of kidney stones. The laser lithotripsy is being conducted using one embodiment of a system comprising a laser assembly 4, such as a holmium:yttrium-aluminium-gamet (Ho:YAG) laser assembly, as known in the art. The beam generated by the laser assembly 4 is directed into the urinary collection system of the subject 2 via a ureteroscope 4a. The subject 2 is provided with saline irrigation of the urinary collection system by an irrigation system 6 through a feed line 6a and a return line 6b.

[0083] The procedure is controlled using a control system, generally indicated as 8. The control system 8 comprises a control unit 10, which controls the operation of the laser assembly 4 and the irrigation system 6, while also providing a user interface 12. The control unit 10 receives signals from the sensor assembly of a sensor device of the present invention disposed within the urinary collection system of the subject 2 by a lead 10a via an I2E serial interface. Embodiments of the sensor device are described in more detail below and shown in Figures 3 to 5. The control unit 10 communicates with a remote patient records system 14 by wireless communication 16.

[0084] Turning to Figure 2, details of the components and their configuration within the system are shown.

[0085] The irrigation system 6 comprises a peristaltic pump 30 receiving an irrigation fluid, such as a saline solution, from a reservoir 32, such as a bottle or bag, via a line 34. Pressurised irrigation fluid is provided by the pump 30 via the feed line 6a to the subject 2. A control valve 36 is present in the feed line 6a, the operation of which is controlled by the control unit 10 by means of a signal line 38. Operation of the pump 30 is controlled by the control unit 10 via a signal line 40. A manual override 70 is provided to allow the control valve 36 to be closed by a user in the event of an emergency, for example when an excessively high irrigation fluid pressure within the urinary system of the subject is detected and the normal functions of the control system to reduce the pressure have failed.

[0086] As described above with reference to Figure 1 , the irrigation system includes a return line 6b, through which irrigation fluid is returned from the urinary collection system of the subject 2. As shown in Figure 2, a pressure sensor 42 and a temperature sensor 44 are provided in the return line 6b to sense the pressure and temperature respectively of the returning irrigation fluid. Signals with data relating to the sensed pressure and temperature are provided to the control unit 10 by signal lines 46 and 48. A pressure sensor 72 is provided to sense the prevailing ambient air pressure and provide a signal with data relating to the sensed ambient pressure to the control unit 10 via a signal line 74.

[0087] As described above with reference to Figure 1 , the system comprises a laser assembly 4, operable to deliver a laser beam to the urinary collection system of the subject 2 through an ureteroscope 4a. The operation of the laser is controlled by the control unit by means of a signal line 50.

[0088] Electrical power is supplied to the laser assembly 4 via a cable 52. A cutoff switch 54 is provided in the cable 52, operated by the control unit 10 via a signal line 56. An override is provided to allow a user to override the action of the control unit 10 to operate the cut-off switch 54 and switch off the power supply to the laser assembly 4. In the embodiment shown in Figure 2, the override comprises a foot- operated override unit 58. The system may alternatively or in addition comprise a hand-operated override unit, such as a push button and / or comprised in the user interface 12.

[0089] As described hereinbefore, the control system 8 comprises a user interface 12. In the embodiment shown in Figure 2, the user interface comprises a visual display 60 for displaying information and parameters relating to the procedure, the operation of the various components and information regarding the state of the subject 2. In addition, the embodiment shown in Figure 2 comprises a touch pad 62 for the user to input data, settings and commands. The touch pad may be omitted in embodiments where the display is a touch screen allowing data input.

[0090] In operation, the system shown in Figures 1 and 2 functions as follows:

[0091] The laser assembly 4 is used to carry an endoscopic procedure, such as laser lithotripsy in a known manner. During this procedure, the laser assembly 4 is operated to generate a beam of light, which is conveyed to a treatment location within the urinary collection system of the subject 2 by the ureteroscope 4a. The urinary collection system of the subject 2 is irrigated by the irrigation system 6 in a known manner by provided a flow of pressurised irrigation fluid to the urinary collection system of the subject 2 by the feed conduit 6a. In the embodiment shown in Figure 2, the irrigation fluid is fed to the subject by the peristaltic pump 30 from the reservoir 32.

[0092] Sensors within the urinary collection system of the subject 2 sense the pressure and the temperature of the fluid within the urinary collection system. Signals with data relating to the pressure and temperature prevailing in the urinary collection system are provided to the control unit 10 along the signal line 10a.

[0093] The control unit 10 is provided with a threshold pressure and a threshold temperature. The threshold values may be preset within the control unit 10. Alternatively or in addition, the user interface 12 may allow the user, such as a surgeon, to input into the control unit 10 threshold values for pressure and temperature.

[0094] In the event the pressure sensed by the sensors within the urinary collection system of the subject 2 exceeds the threshold pressure, the control unit 10 acts to reduce the pressure of the irrigation fluid being fed to the subject through the line 6a. The control unit 10 may adjust the operation of the pump 30, such that the output pressure of the pump is reduced. Alternatively, the control unit 10 may turn off the pump 30. Should a problem arise and the control unit 10 be unable to adjust the irrigation fluid pressure as required, the control unit may operate to shut the control valve 36 in the feed line 6a, thus stopping the flow of irrigation fluid to the subject.

[0095] Once the sensed pressure within the urinary collection system of the subject returns to an acceptable level below the threshold pressure of the control unit, the control unit 10 will activate the pump 30 and / or the control valve 36, as required, to restore or increase the flow of irrigation fluid to the subject.

[0096] In the event the temperature sensed by the sensors within the urinary collection system of the subject 2 exceeds the threshold temperature of the control unit 10, the control unit 10 acts to reduce the energy being output by the laser assembly 4 and provided to the treatment location within the urinary collection system of the subject 2. Where the laser assembly 4 permits, the control unit 10 may vary the operation of the laser assembly to reduce the energy being output. Alternatively, the control unit 10 may switch off the laser assembly 4. This may be achieved using the cut-off switch 54 in the power supply cable 52 of the laser assembly 4. In this way, no modification of or direct interaction with the laser assembly 4 is required.

[0097] The system shown in Figure 2 provides the user with an override facility, allowing the user, such as a surgeon, to override the action of the control unit to shut down the laser assembly 4 and permit continued operation. This option may be exercised where the user, such as a surgeon, considers it acceptable to continue the laser treatment.

[0098] Data received by the control unit 10 from the pressure sensor 42 and the temperature sensor 44 relating to the conditions of the irrigation fluid leaving the subject are used to identify abnormal operation of the system, for example a blockage preventing the irrigation fluid from reaching the treatment site within the urinary collection system of the subject.

[0099] Data received by the control unit 10 from the pressure sensor 72 regarding the prevailing ambient air pressure, allow the control unit 10 to determine the pressure of the irrigation fluid in both relative and absolute terms. These pressure data are displayed to the user, who may select the displayed pressure values to be in either one or both of relative or absolute pressures.

[0100] The user interface 12 provides a visual display, preferably a touch-screen display, to the user by way of the display 60. The visual display may show any suitable parameters during the procedure. In the event of a sensed pressure or temperature within the urinary collection system of the subject being above the threshold values of the control unit, the user interface displays a visual warning to the user. Preferably, the user interface 12 also provides an audible warning when a threshold has been exceeded.

[0101] With reference to Figure 3, there is shown one embodiment of a sensor device of the present invention. The sensor device may be used for sensing pressure and / or temperature at an in vivo location within the urinary collection system of the subject 2.

[0102] The sensor device, generally indicated as 102, has a proximal end portion 104 and a distal end portion 106. A housing 108 is provided at the proximal end portion 104 of the device 102 and has a connector 110 at its proximal end for connecting the device to an apparatus or system by means of a cable (not shown for clarity). A flexible conduit 112 extends from the distal end of the housing 108. The conduit 112 is a silicone, PVC or PTFE tube having a lumen. The conduit 112 is a 3 French tube, allowing the distal end portion of the conduit to be inserted into a subject and located at an in vivo location within the subject, such as within the urinary collection tract of the subject.

[0103] Figure 4 is a cross-sectional view of the distal end portion 106 of the sensor device 102 of Figure 3. As shown in Figure 4, the conduit 112 has a bore or lumen 120 therethrough and a distal end 122 having an opening 124. A sensor assembly 126 is disposed within the lumen 120 spaced from 5 to 15 mm from the distal end 122 and the opening 124. The sensor assembly 126 comprises a SMI-1 Intrasense sensor available from TE Connectivity and operable to detect fluid pressure and temperature. The sensor assembly 126 is connected to a cable 128 comprising 3 wires 128a, 128b, 128c for providing electrical power to the sensor assembly and providing a connection for the serial transmission of electrical signal data from the sensor assembly. The sensor assembly 126 is retained in position within the lumen 120 of the conduit 112 by the cable 128, as will be described in more detail below.

[0104] In use, fluid surrounding the distal end portion of the conduit 112 at the in vivo location enters the lumen 120 of the conduit 112 through the opening 124 in the distal end 122, thereby exposing the sensor assembly 126 to the fluid at the conditions, such as temperature and pressure, prevailing at the in vivo location. The sensor is protected from damage as a result of its location within the lumen 120, spaced from the distal end 122.

[0105] Turning to Figure 5, there is shown a cross-sectional view of the proximal end portion 104 of the sensor device 102 of Figure 3. The housing 108 has a housing wall 140 defining a cavity 142. The housing 108 is formed from two housing halves, each moulded from a suitable medical grade plastic, with the view in Figure 5 showing the interior of one housing half. The housing 108 has a distal end 144 and a proximal end 146. The distal end 144 of the housing 108 has an opening 150, into which the proximal end 148 of the conduit 112 extends. The inner surface of the housing wall 140 is provided with annular ridges 152, which grip the outer surface of the conduit 112, retaining the proximal end of the conduit within the housing.

[0106] An interface 160 is held within the housing 108. The wires 128a, 128b, 128c of the cable 128 are connected to the interface. In the embodiment shown in Figure 5, the interface comprises a printed circuit board (PCB) on which are mounted connections for the wires 128a, 128b, 128c, a power supply for providing electrical power to the sensor assembly via wires 128a and 128b, a serial interface chip for receiving serial signal data from wire 128c, and a calibrator chip. The interface 160 is connected by a cable 168 to a connector 166 disposed in the proximal end of the housing 108, having a socket 166a for connecting via a suitable cable (not shown) to an apparatus or system for receiving signal data from the sensor assembly. The interface 160 may comprise other components, for example a transmitter for transmitting signal data wirelessly to a remote receiver.

[0107] As shown in Figure 5, the housing comprises a staggered array of pins 170, around which a portion of the cable 128 extends in a substantially zig-zag pattern. In this way, the cable 128 is securely held within the housing 108, preventing the cable 108 moving within the conduit 112, in turn acting to retain the sensor assembly 126 in position in the distal end portion of the conduit 112.

[0108] To assemble the device shown in Figures 3, 4 and 5, the following procedure may be followed. The sensor assembly is connected to the distal end of the wires 128a, 128b, 128c of the cable 128. The proximal end of the cable 128 is inserted into the distal end of the conduit 112 and drawn through the conduit. The proximal end portion of the wires 128a, 128b, 128c are connected to the interface 160. The interface 160 and the connector 166 are connected. The proximal end of the conduit 112 is placed in one half of the housing 108, the proximal end portion of the cable wound around the pins 170, to locate the cable 128, and the interface 170 and the connector 166 located in the housing half. The second half of the housing 108 is then attached, clamping the proximal end portion of the cable 128 and enclosing the components within the housing. Other procedures for assembly the sensor device may be employed. Referring to Figure 6, there is shown a cross-sectional view of the distal end portion 106 of an alternative embodiment of the sensor device of the present invention. As shown in Figure 6, in common with the embodiment shown in Figure 3, the conduit 112 has a bore or lumen 120 therethrough and a distal end 122 having an opening 124. In addition to the opening 124 in the distal end 122 of the conduit, there is provided a pair of openings 124a, 124b in the wall of the conduit 112 spaced from the distal end 122. A sensor assembly 126 is disposed within the lumen 120 spaced from 5 to 15 mm from the distal end 122 and the opening 124. The sensor assembly 126 has the same general configuration shown in Figure 3 and discussed above. In use, fluid surrounding the distal end portion of the conduit 112 at the in vivo location enters the lumen 120 of the conduit 112 through the opening 124 in the distal end 122 and the openings 124a, 124b in the wall of the conduit 112, thereby exposing the sensor assembly 126 to the fluid at the conditions, such as temperature and pressure, prevailing at the in vivo location.

[0109] Referring to Figure 7, there is shown a cross-sectional view of the proximal end portion 104 of an alternative embodiment of the sensor device of the present invention. As shown in Figure 7, in common with the embodiment shown in Figure 5, the sensor device 102 comprises a housing 108. The housing 108 and the components within the housing are as shown in Figure 5 and described above.

[0110] In the embodiment shown in Figure 7, the housing 108 comprises a single pin 180, around which a portion of the cable 128 is wound in a helical pattern. Again, this acts to secure the cable 128 within the housing 108 and the conduit 112, in turn securing the sensor assembly 126 in position in the lumen 120 of the conduit 112.

[0111] Figure 8 is a representation of one side of the renal system of the subject.

[0112] The renal system comprises a kidney 200, from which extends a ureter 202 to a bladder 204. A urethra 206 extends from the bladder 204. The kidney comprises a renal pelvis 208 and a plurality of calyxes 210.

[0113] As represented in Figure 8, a sensor assembly 102 of the present invention is shown in place, with the conduit 112 extending through the upper region of the ureter 202 and the sensor assembly 126 in the distal end portion of the conduit 112 disposed in the renal pelvis 208 of the kidney 200, having been introduced through the urethra 206 and the bladder 204 in known manner.

Claims

CLAIMS1 . A sensor device for detecting one or more parameters at an in vivo location within a subject, the sensor device comprising: a housing; a connector for providing signal data relating to the one or more parameters; a conduit having a proximal and a distal end, the conduit extending at its proximal end from the housing, wherein the conduit comprises a cavity in the distal end portion of the conduit, the conduit having an opening in the distal end portion communicating the cavity with the exterior of the conduit; a sensor assembly disposed in the cavity in the distal end portion of the conduit comprising one or more sensors operable to sense one or more parameters in the surroundings of the distal end portion of the conduit, in use the sensor assembly being exposed to fluid entering the cavity through the opening in the distal end of the conduit; and a cable connected at its distal end to the sensor assembly and at its proximal end to the connector for carrying electrical signals from the sensor assembly to the connector.

2. The sensor device according to claim 1 , wherein the proximal end of the conduit is engaged with the housing.

3. The sensor device according to claim 2, wherein the housing comprises one or more members engaging with the proximal end portion of the conduit.

4. The sensor device according to any preceding claim, wherein the conduit comprises an opening at its distal end and / or one or more openings in the wall of the conduit spaced from the distal end of the conduit.

5. The sensor device according to any preceding claim, wherein the conduit comprises a lumen extending longitudinally along part or all of the length of the conduit.

6. The sensor device according to any preceding claim, wherein the conduit is a 3 French to 4 French tube.

7. The sensor device according to any preceding claim, wherein the sensor assembly is spaced from 5 to 15 mm from the distal end of the conduit.

8. The sensor device according to any preceding claim, wherein the sensor assembly is operable to detect one or both of temperature and pressure of fluid within the cavity.

9. The sensor device according to any preceding claim, wherein the sensor assembly comprises a single sensor operable to detect both temperature and pressure.

10. The sensor device according to any preceding claim, wherein the sensor assembly comprises one or more Micro Electro Mechanical Systems (MEMS) sensors.

11. The sensor device according to any preceding claim, further comprising means for holding and securing the cable in position.

12. The sensor device according to claim 11 , wherein the proximal end portion of the cable is held in a convoluted pattern by a holding formation within the housing.

13. The sensor device according to any preceding claim, wherein the proximal end of the cable is connected to the connector.

14. The sensor device according to any of claims 1 to 12, wherein the proximal end of the cable is connected indirectly to the connector via an interface.

15. The sensor device according to claim 14, wherein the interface comprises a calibrator for calibrating the sensor assembly.

16. The sensor device according to any preceding claim, further comprising a wireless transmitter for transmitter wireless data signals.

17. A system for performing a procedure on a subject, the apparatus comprising a sensor device according to any preceding claim.

18. A system for controlling a laser assembly during an endourological procedure being conducted on a subject, the system comprising: an irrigation system comprising: a fluid delivery system for delivering an irrigation fluid intra-renally to the subject from an irrigation fluid reservoir; and a control system comprising: a temperature sensor for disposing at an intra-renal location within the subject and operable to generate a temperature signal corresponding to the temperature the intra-renal location; a pressure sensor for disposing at an intra-renal location within the subject and operable to generate a pressure signal corresponding to the pressure of fluid at the intra-renal location; wherein the temperature sensor and / or the pressure sensor are comprised in a sensor device according to any of claims 1 to 17; and a control unit configured for: receiving the temperature signal and operable to vary the operation of the laser assembly when the temperature at the intrarenal location exceeds a threshold temperature; andreceiving the pressure signal and controlling the operation of the pump to vary the fluid pressure at the intra-renal location.

19. A system for conducting an endourological procedure employing a laser assembly, more especially a laser lithotripsy procedure on a subject, the system comprising: a laser assembly for generating a laser beam for deploying at an in vivo location within the endourological system of the subject; a temperature sensor for disposing at an intra-renal location within the subject and operable to generate a temperature signal corresponding to the temperature the intra-renal location; an irrigation system comprising: a pressure sensor for disposing at an intra-renal location within the subject and operable to generate a pressure signal corresponding to the pressure of fluid at the intra-renal location; and a fluid delivery system for delivering an irrigation fluid intra-renally to the subject from an irrigation fluid reservoir; and a control unit configured for: receiving the temperature signal and operable to interrupt the operation of the laser assembly when the temperature at the intra-renal location exceeds a threshold temperature; and receiving the pressure signal and controlling the operation of the pump to vary the fluid pressure at the intra-renal location; wherein the pressure sensor and / or the temperature sensor are comprised in the sensor assembly of a sensor device according to any of claims 1 to 17.

20. A method of controlling an apparatus for performing a procedure on a subject, the method comprising sensing a parameter at an in vivo location within the subject and operating the apparatus in response to the sensed parameter; wherein the parameter is sensed using a sensor device according to any of claims 1 to 17.21 . A method for controlling the operation of a laser assembly during a laser endourological procedure on a subject, the method comprising: providing a flow of the irrigation fluid to the intra-renal location within the subject; sensing the temperature at an intra-renal location within the subject; sensing the intra-renal fluid pressure within the subject; and controlling the flow of the irrigation fluid in response to the sensed intra-renal fluid pressure; comparing the sensed temperature with a threshold temperature; and in the event the sensed temperature exceeds the threshold temperature varying the operation of the laser assembly and / or the flow of irrigation fluid to the intra-renal location; wherein the pressure and temperature are sensed using a sensor device according to any of claims 1 to 17.

22. A system for irrigation of the renal system of a subject, the system comprising: a fluid delivery system for delivering an irrigation fluid intra-renally to the subject from an irrigation fluid reservoir; and a control system comprising:a sensor device according to any of claims 1 to 17, wherein the sensor assembly comprises a pressure sensor and is for disposing at an intra-renal location within the subject and operable to generate a pressure signal corresponding to the pressure of fluid at the intra-renal location; and a control unit for receiving the pressure signal and controlling the operation of the fluid delivery system to vary the fluid pressure at the intra-renal location.

23. A method for providing an irrigation fluid to an intra-renal location within a subject during an endourological procedure, the method comprising: providing a flow of the irrigation fluid to the intra-renal location within the subject; sensing the intra-renal fluid pressure within the subject using a sensor device according to any of claims 1 to 17; and controlling the flow of the irrigation fluid in response to the sensed intra-renal fluid pressure.

24. A system for operating a laser assembly during an endourological procedure being conducted on a subject, the system comprising: a control system comprising: a sensor device according to any of claims 1 to 17, wherein the sensor assembly comprises a temperature sensor; and a control unit for receiving the temperature signal and operable to vary the operation of the laser assembly when the temperature at the intra-renal location exceeds a threshold temperature.

25. A method for controlling the operation of a laser assembly during a laser endourological procedure on a subject, the method comprising:sensing the temperature at an intra-renal location within the subject using a sensor device according to any of claims 1 to 17; comparing the sensed temperature with a threshold temperature; and in the event the sensed temperature exceeds the threshold temperature varying the operation of the laser assembly.

Images