EXTERNAL VENTRICLE CATHETER COUPLED WITH A SONOGRAPHIC STYLE FOR IMAGE-GUIDED PLACEMENT

Description

TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a surgical ventricular shunt device for the transient (EVD: External Ventricular Shunt) or permanent (e.g., PVD: Ventriculoperitoneal Shunt) diversion of cerebrospinal fluid from the cranial cavity, using a drain implanted in the ventricles and connected to a drainage system, when the cerebrospinal fluid cannot circulate freely. The invention relates to both the EVD and PVD catheters, and their use during the implantation procedure, for the treatment of acute or chronic hydrocephalus and thus ventricular dilation. The present invention has industrial applications in the medical field, and particularly in the surgical field.

[0002] Hydrocephalus is an abnormal accumulation of fluid within the ventricular system, increasing its volume and therefore intracranial pressure. Ventricular drainage is performed using a catheter to control intracranial pressure by diverting cerebrospinal fluid (CSF) and thus reducing intracranial pressure.

[0003] The EVD catheter consists of a ventricular drainage catheter, usually made of silicone, placed on a rigid guidewire that the surgeon uses to implant the EVD catheter into the patient's ventricular system. A small hole is drilled through the skull (burr hole), and the EVD catheter is inserted through the dura mater and then the brain, penetrating the cerebral parenchyma to the target ventricle.

[0004] Freehand placement of the EVD catheter requires the neurosurgeon to estimate the three-dimensional position of the target ventricle, usually based on external anatomical landmarks. The ventricle is typically only 0.5 to 3 cm in diameter and can be located at a depth of view of 5 to 50 millimeters, preferably 4 cm or more. Once the target ventricle's position is estimated, the EVD catheter is advanced through the brain toward the target ventricle. The freehand method provides no way to account for potential irregularities in the patient's anatomy that are not externally apparent. Factors such as intracranial space-occupying lesions (hematoma, edema, tumor, etc.), residual porencephalic cavities, genetic variability, and others can also affect the localization of the target ventricle.

[0005] The "intuitive" placement of a catheter sometimes requires the practitioner to make several attempts, resulting in more than one pass through the brain tissue to achieve the required placement of the EVD catheter.

[0006] According to the literature, up to 65% of implanted ventricular shunt leads have a distal tip in a suboptimal position (outside the optimal ventricular target). Of these, nearly one-third are non-functional and require revision and reinsertion. Possible complications associated with incorrect EVD catheter placement can include intracerebral hemorrhage, stroke, damage to adjacent brain structures, and the need for further surgery to replace the misplaced catheter. Higher infection rates are also reported when multiple EVD placement attempts are required.

[0007] Several solutions have been explored, including assisting catheter positioning with an imaging system outside the skull (ultrasound on the surface of the cerebral parenchyma in parallel with the EVD probe requiring a second burr hole, brain scan with stereotaxic or virtual reality guided placement), the use of a GHAJAR guide to constrain positioning relative to the surface of the skull, the use of an ultrasound stylet introduced into the drain to provide depth information by linear ultrasound which guides the user towards the ventricle. PREVIOUS STATE OF THE ART

[0008] Prior art patent WO2015108917 describes an implantable shunt device for draining cerebrospinal fluid from a subarachnoid space of a patient, comprising a shunt having first and second opposing ends, the second end being designed to penetrate a wall of a sigmoid, transverse, straight or sagittal sinus of the patient, a non-return valve, a hollow passage extending between the second end and the non-return valve such that cerebrospinal fluid can be drained through the second end and expelled through the valve, and a mechanism coupled to the shunt and designed to anchor the shunt at a desired location near the subarachnoid space.

[0009] We are also familiar with the article "Dual Orientation 16-MHz Single-Element Ultrasound Needle Transducers for Image-Guided Neurosurgical Intervention" (authors Yun Jiang, Zhen Qiu, et al.), School of Engineering & Physical Sciences, Institute of Sensors, Signals & Systems, Institute of Mechanical, Process & Energy Engineering, Energy Academy. This article concerns the incorporation of an ultrasound device into the type of biopsy needles commonly used as an interventional tool to provide feedback to neurosurgeons during surgical procedures. To identify the most appropriate path to access a targeted tissue site, single-element transducers oriented either forward or laterally were used.

[0010] In a different field, namely spinal puncture, which allows for the targeted collection of a cerebrospinal fluid sample not from the skull but from the spinal column, patent application WO2017192603 is known. This application relates to a needle placement system comprising a needle and an ultrasonic transducer element attached to the distal end of the needle. The system also includes a needle constraint assembly configured to receive and constrain the needle only to rotational degrees of freedom within a range of angular motion. The system further includes an ultrasonic data processor configured to communicate with the transducer element to receive ultrasonic detection signals and to communicate with the needle sensor system to receive angular orientation signals from the needle.

[0011] This prior art procedure involves interventions performed by emergency physicians or neurologists to collect cerebrospinal fluid (CSF), a vital fluid in the diagnosis of many diseases and conditions of the central nervous system (CNS). To perform this procedure, a physician palpates the lower back and identifies vertebrae L3 through L5. Once located, the physician applies a local anesthetic before inserting and advancing a needle, typically a Quincke needle.

[0012] This solution is not suitable for an intervention to implant a drain in the ventricles intended to be connected to a drainage system, when cerebrospinal fluid cannot circulate freely.

[0013] Also known is US patent application 20070083100A1, which describes a ventriculostomy catheter with a catheter wall defining a central lumen, and a removable stylet device positioned within the central lumen. An ultrasound probe is disposed within the catheter wall and remains in place at the distal end of the catheter when the stylet is removed. Thus, it can be used to provide substantially continuous ultrasound imaging and monitoring during positioning, fluid drainage, or the insertion of medical instruments into the brain via the catheter's central lumen. The distal end of the catheter is always open, allowing for the ingress of bodily fluids.

[0014] Patent application WO1996029011A1 describes a rigid, fiber-optic, ultrasonic stylet (1) placed in a modified intracranial catheter made of Silastic, enabling indirect and direct real-time visualization through the distal end of the catheter. This stylet is equipped with optical fibers and an ultrasonic transducer allowing vision through the catheter tip.

[0015] US patent application 2014358007 relates to the positioning of a medical device within or near a substantially fluid-filled compartment within a human body, such positioning being aided by pulse-echo ultrasound and a temporal stretching technique. In one embodiment, a small ultrasound transducer is placed near the tip of a catheter intended to be positioned within a cerebral ventricle to drain cerebrospinal fluid. DISADVANTAGES OF PREVIOUS ART

[0016] Previous art solutions are not entirely satisfactory because they only provide depth information in a one-dimensional mode, exploring only a single line: the axial line of the ultrasound probe. This information only partially assists the practitioner in determining the appropriate guidance and probe orientation. These solutions are designed to minimize cross-sectional area to allow passage through thin drainage catheters with a diameter of less than 1.7 mm.

[0017] To exploit the information provided by prior art solutions, the practitioner must learn to interpret them, which may require a significant amount of time before they are able to interpret them immediately, reflexively, during an intervention. DESCRIPTION OF THE INVENTION

[0018] The present invention aims to overcome the drawbacks of the prior art by means of a cerebrospinal fluid drainage system comprising an EVD probe and an ultrasound stylet insertable into said EVD probe characterized in that said ultrasound stylet comprises a rigid tube provided at its distal end with a scanning transducer forming a beam whose axis is directed along the longitudinal axis of said ultrasound stylet.

[0019] In its most general sense, the invention relates to a cerebrospinal fluid drainage system comprising an EVD or VPD probe according to claim 1.

[0020] It consists of a flexible tube with an outer diameter between 1.9 and 5 millimeters and a stylus equipped at its distal end with an ultrasound transducer, insertable into said tube, and an ultrasound scanner comprising a display screen for an image calculated based on the signals provided by said ultrasound probe, characterized in that: said stylus comprises a rigid tube of an outer diameter corresponding to the inner diameter of said tube containing only the power supply wires of said transducer, excluding an optical fiber, said rigid tube being provided at its distal end with a transducer of a diameter identical to the diameter of said rigid tube and having an imaging depth in the axis of the rigid tube of between 0 and 100 millimeters, the distal end of said tube (10) being closed by a solid and deformable tip (12) the proximal end of said tube ( figure 6This device features a securing system to the proximal end of the ultrasound probe. This securing system has five objectives: 1) to limit the longitudinal impaction of the ultrasound stylet into the shunt tube during insertion; 2) to restrict rotation between the tube (10) and the ultrasound stylet; 3) to fix the insertion depth of the stylet into the tube; 4) to create a secure system between the ultrasound stylet and the shunt to prevent movement of either component; and 5) to generate a fluid space distal to the ultrasound probe, conducive to its use. The securing system may be of the screw, bayonet, anchor, Velcro, or locking type (this list is not exhaustive). In one variant, the proximal end of the tube carrying the securing system is reinforced and detachable from its functional portion.The removable portion can be pre-punched or sectioned intraoperatively using a sharp instrument such as a scalpel or medical scissors. Preferably, this detachable portion will be transparent to allow visual confirmation of proper assembly. In another variant, the fixing portion is a screw thread (Huer-lock type) and is non-removable, facilitating and securing its connection to the collection tubing and its bag. figure 6 ) thus limiting mismatches compared to a conventional interlocking system.

[0021] In one variant, the tube has one or more internal lateral bores with their longest longitudinal axis complementary to the central bore. Some or all of these bores conform to the complementary shape of the ultrasound stylet (in the form of segmental fins or longitudinal blades) to maximize their rigidity and restrict the degree of distal rotation of the assembly. In another variant, one or more of these bores advantageously allow the instillation, from the proximal end of the assembly, of a transechoic fluid such as physiological saline at the interface between the piezoelectric elements of the ultrasound stylet and the inner surface of the tip of the DV tube.

[0022] The cross-section of said tube is round. In one variant, the cross-section of the tube will be asymmetrical, thickened opposite the lateral internal bores in order to maintain satisfactory resistance to bending after removal of the ultrasound probe ( figure 6) The ultrasound stylet and possibly the DV tube present a proximal visual marker allowing the orientation of the ultrasound probe to be known and facilitating the spatial localization of the operator during the intraparenchymal insertion of the assembly.

[0023] The ultrasound scanner provides B-mode ultrasound imaging.

[0024] According to one variant, said ultrasound scanner provides B-mode ultrasound imaging associated with at least one other imaging modality including color mode, pulsed Doppler, power and 3D mode.

[0025] Advantageously, said transducer is a scanning transducer.

[0026] According to one variant, the system further comprises a sterile sheath surrounding said stylet and the end of which, in which said transducer is engaged, contains an ultrasound gel.

[0027] According to another variant, the distal end of the tube has a shape complementary to the external shape of said transducer.

[0028] According to a first embodiment, said tip has a conical shape. According to another embodiment, said tip has a hemispherical / alternative shape, the purpose of which is to limit the generation of optical aberrations by the deviation of the ultrasound beam it generates (ultimately responsible for ultrasound artifacts).

[0029] The tip and / or the entire DVE tube are made of biocompatible materials with biomechanical properties similar to those typically expected for a shunt probe and, advantageously, with a material exhibiting the lowest possible ultrasound beam attenuation coefficient. The thickness of this tip may advantageously be reduced for the same purpose.

[0030] Advantageously, the tip contains either ultrasound gel or sterile instilled water. This instillation can be performed before assembling the ultrasound transducer and tube by first immersing the DV tube in a basin of physiological saline or by instilling the gel through the tube's internal lumen. Alternatively, the assembly is fixed in place, and antegrade insertion is achieved through the lateral internal bores or by direct puncture using a needle from the conical tip of the DV tube.

[0031] According to one variant, said system further includes a computer running a computer program for preprocessing the signal supplied by said scanning transducer, said preprocessing consisting of applying compensation for variations in propagation conditions in said tube tip.

[0032] Preferably the operating frequency of said transducer is between 4 MHz and 15 MHz, more advantageously 10 MHz.

[0033] According to one variant, the probe tip contains an echogenic marker BRIEF DESCRIPTION OF THE FIGURES

[0034] Other features and advantages of the invention will become apparent from the following detailed examples of embodiments, with reference to the attached figures which respectively represent: [ Fig. 1 ] there figure 1 represents a cross-sectional view of a system according to the invention. Fig. 2 ] there figure 2 represents a view of the probe tip according to a first example of its implementation. Fig. 3 ] there figure 3 represents a view of the probe tip according to a second embodiment. Fig. 4 ] there figure 4 represents a cross-sectional view of the probe tip according to a third embodiment. Fig. 5 ] there figure 5 represents a cross-sectional view of the probe tip according to a fourth embodiment example [ Fig. 6A ] there figure 6Arepresents a view of the stylus in a first position [ Fig. 6B ] there figure 6B represents a view of the stylus from a second position [ Fig. 6C ] there figure 6C represents a view of the stylus from a third position [ Fig. 7A ] there figure 7A represents a cross-sectional view of a first variant of the tube geometry according to the invention [ Fig. 7B ] there figure 7B represents a cross-sectional view of a second variant of the tube geometry according to the invention [ Fig. 7C ] there figure 7C represents a cross-sectional view of a third variant of the tube geometry according to the invention [ Fig. 7D ] there figure 7D represents a cross-sectional view of a fourth variant of the tube geometry according to the invention [ Fig. 7E ] there figure 7E represents a cross-sectional view of a first variant of the tube according to the invention [ Fig. 7F ] there figure 7Frepresents a cross-sectional view of a first variant of the tube according to the invention [Fig. 7G] Figure 7G represents a cross-sectional view of a second variant of the tube according to the invention [ Fig. 8A ] there figure 8A represents a cross-sectional view of the tube according to the invention with a solid tip [ Fig. 8B ] there figure 8B represents a cross-sectional view of the tube according to the invention with a solid tip after introduction of the transechoic liquid [ Fig. 8C ] there figure 8C represents a cross-sectional view of the tube according to the invention with a solid tip after introduction of the liquid and the ultrasound stylet [ Fig. 8D ] there figure 8D represents a cross-sectional view of the tube according to the invention with a hollow tip [ Fig. 8E ] there figure 8E represents a cross-sectional view of the tube according to the invention with a hollow tip after introduction of the transechoic liquid [ Fig. 8F ] there figure 8Frepresents a cross-sectional view of the tube according to the invention with a hollow tip after insertion of the ultrasound stylet and then introduction of the liquid through the groove [ Fig. 8G ] there figure 8G represents a cross-sectional view of the tube according to the invention with a hollow tip after introduction of the liquid and the ultrasound stylet [ Fig. 9 ] there figure 9 represents a cross-sectional view of the tube according to the invention [ Fig. 10 ] there Figure 10 represents a cross-sectional view of the ultrasound probe [ Fig. 11 ] there figure 11 represents a cross-sectional view of the system formed by the stylet engaged in the ventricular bypass tube. DESCRIPTION OF AN EXAMPLE OF A PROJECT

[0035] The invention relates to a system composed of a DVE or DVP probe constituting a drainage tube (10) and an ultrasound stylet for guided implantation (20).

[0036] The outer diameter of the drainage tube (10) is typically between 1.9 mm and 5 mm, and the inner diameter between 1.7 mm and 3.5 mm. The outer diameter of the stylet (20) is typically 0.5 mm smaller than the inner diameter of the drainage tube, with a central channel for the passage of the electrical wires connecting the transducer to the ultrasound scanner.

[0037] The tip thickness at the distal end of the tube ranges from 1 to 7 mm, depending on the ultrasound probe's power and the tip's shape. This tip is solid, or more preferably, it has a central ellipsoidal or quadrangular bore that conforms to the surface of the Doppler stylet. In an assembly, this bore is maximized, and can be ellipsoidal, conical, pyramidal, or quadrangular, or a similar shape, to accommodate the Doppler stylet-flexible sheath assembly. The sheath material may be, for example, silicone, a silicone-based material (i.e., containing at least 10% silicone), rubber, plastic, polyamide, polyether block amide, polycarbonate, polyimide, or polytetrafluoroethylene; this list is not exhaustive.

[0038] The drainage tube (10) is perforated distally and laterally by multiple holes (12) approximately 2 mm in diameter over a length of approximately 20 mm. These openings may be pores, holes, orifices, or slits, and they pass completely through the membrane of the tube (10). Preferably, these openings are sized to allow the passage of water, cerebrospinal fluid, and blood. These pores, holes, orifices, or slits may be adapted according to their capacity to allow the flow of cerebrospinal fluid, with variable shapes such as cylindrical, conical, or oval; this list is not exhaustive. The distance between the holes is variable, ranging from 1 to 4 mm, to ensure proper flow of cerebrospinal fluid.

[0039] The tip forms a conical, pyramidal, or ellipsoidal point (11) and is non-rigid. This tip is solid with a proximal internal bore to fit the shape of the distal end of the ultrasound probe, but may have an internal bore shaped to receive a flexible sheath-Doppler stylet complex or a liquid interface.

[0040] The flexible drainage tube (10) is intended for short- or long-term implantation in a patient to drain the ventricular system in cases of acute or chronic hydrocephalus. This tube (10) is connected to a gravity shunt system using a collection bag once it is in place in the case of EVD and to a drainage system connected to the peritoneum or the vascular system in the case of VPD.

[0041] In the case of ventricular drainage (VD), the flexible drainage tube has the same characteristics in its distal portion (tip, holes, pores, or drainage orifices). The intracranial length is 4 to 9 cm with a right angle allowing the tube to be applied to the skull using a reservoir, followed by a drainage tube that will be connected to the shunt valve. The junction between the shunt and the ultrasound probe can be cut to connect it to the valve.

[0042] The channel of this drainage tube (10) accommodates an ultrasound stylet (20) formed by a removable rigid mandrel whose length exceeds that of the drainage tube (10), to facilitate the introduction of the device into the cerebral parenchyma and its removal after placement of the EVD / VP probe. This ultrasound stylet includes a scanning ultrasound transducer (21) powered by wires (22). For example, this is an ALOKA UST 534 transducer. This ultrasound stylet is inserted into the drainage tube along the bore using the fin, and its final position is locked by the proximal fixation system to secure the assembly and create a distal fluid space suitable for use with the ultrasound probe. The insertion of the assembly is oriented according to the marker on the ultrasound stylet indicating the orientation of the ultrasound beam and its anterior portion.

[0043] The active element of the transducer consists primarily of a piezoelectric material, possibly a piezocomposite, possibly multilayer, and a set of at least two electrodes that create an electric field within the thickness of the piezoelectric material. Preferably, one or more acoustic matching layers are integrated into this active element, on its front face, to facilitate acoustic transfer to the front of the transducer.

[0044] The transducer is advantageously glued to the distal end of the stylus (20) by an epoxy glue.

[0045] This transducer can consist of an array of piezoelectric micro-transducers, or a single transducer driven by an oscillating motion via a MEMS-type support. It delivers a 2D or 3D signal of the environment in front of the conical tip (11) to allow the operator to guide the advancement and orientation of the rigid stylet during the placement of the drain through the patient's brain parenchyma. The signals are processed by a 2D ultrasound scanner in B-mode to provide an image of the area in front of the probe.

[0046] The operating frequency is typically 10 MHz. The transducer (21) is connected to an ultrasound scanner.

[0047] This ultrasound device must have a "B" ultrasound mode (2D anatomical imaging), possibly accompanied by a "C" mode (color), a "D" mode (Doppler), a power mode, and / or a 3D mode, with an imaging depth between 0 and 50-100 millimeters. The ultrasound probe is preferably linear, curvilinear, or micro-convex, but can be any type of ultrasound probe that allows obtaining a B-type ultrasound image along the longitudinal axis of the stylet (adapted IVUS (intravascular) microprobe, trapezoidal probe, etc.).

[0048] The signal provided by the transducer can be corrected, in case of inhomogeneity of the tip (11) by a computer applying a digital processing of compensation of the variations in transmission induced by the material constituting the tip (11) and the variations in thickness as a function of the angle of firing. TIP CONFIGURATION

[0049] THE figures 2 to 5 illustrate different configurations of the tip (11) of the flexible tube (20). It can be conical as illustrated by the figure 2 or hemispherical as illustrated by the figure 3 .

[0050] The distal end of the ventricular shunt is produced in such a way as to be as atraumatic as possible, in a biocompatible material that is as transechoic as possible.

[0051] Its thickness and geometric shape will aim to reduce optical aberration artifacts and the attenuation of the ultrasound beam.

[0052] It can also receive an ultrasound gel (15) lodged between the probe (21) and the inside of the tip (11) as shown in figure 4 or 5 .

[0053] The sterile ultrasound gel is secured to the tip of the ultrasound stylet by a sterile flexible sheath (16), forming a flexible sheath-Doppler stylet complex which is loaded within the shunt probe. In this variant, the internal diameter of the EVD probe is slightly larger than the external diameter of said flexible sheath-Doppler stylet complex ( Fig. 2 ). The length of the flexible envelope is such that once unrolled over the doppler stylus, it always exceeds the surface of the skull and remains less than the length of the doppler stylus (approximately between 6 and 20cm).

[0054] Alternatively, a transechoic fluid such as physiological saline is instilled directly into the transducer-tip interface of the shunt tube. This instillation can be performed before assembling the tube-sensor assembly, or after assembly by means of an internal bore of the tube complementary to the central bore receiving the stylet, or by direct puncture with a fine needle of a space on the posterior surface of the tube tip. In these variations, the length of the ultrasound stylet portion inside the shunt tube will be slightly shorter than the internal bore of the tube to create this fluid space suitable for use with the ultrasound probe. Optionally, the probe tip includes a lateral echogenic marker to provide a visible reference on the transcranial ultrasound image. CONFIGURATION OF THE PROXIMAL PART

[0055] THE figures 6illustrate the male and female threads between the ultrasound probe and the shunt tube, which secure the two components together. Once locked, the threads allow: 1) limiting the longitudinal impaction of the shunt tube during insertion, 2) restricting rotation between the tube (10) and the ultrasound stylet, 3) fixing the insertion depth of the stylet in the tube, 4) creating a rigid system between the ultrasound stylet and the shunt to prevent movement of either component, and 5) generating a fluid space distal to the ultrasound probe, conducive to its use. This last point ensures a watertight fluid space at the tube / ultrasound interface, regardless of any movements imparted to the assembly at its distal end. figure 6 ).

[0056] In one variant, the threaded connection of the bypass tube allows it to be connected to the collection tubing and the bag (X), thus reducing the risk of misalignment compared to a conventional socket system. In another variant, the fixation system is located on the most proximal segment of the tube and is removable during surgery. CONFIGURATION OF THE ANTERIOR SECTION OF THE TUBE

[0057] THE figures 6A to 6C illustrate the anterior part of the said ellipsoidal-shaped tube with a thicker anterior part with a groove in its internal part to receive the fin of said ultrasound probe in order to avoid false paths and to secure the introduction.

[0058] On its anterior outer part is a marking indicating the orientation of the ultrasound probe and the direction of insertion into the cerebral parenchyma ( figure 6 ). IMPLEMENTATION OF THE INVENTION

[0059] A small incision is made in the skin using an anatomical landmark anterior to the coronal suture, 2 or 3 cm lateral to the midline. Next, a burr hole approximately 5 mm to 3 cm in diameter is created, with opening and sometimes coagulation of the dura mater.

[0060] Instillation of sterile water with a syringe along the internal bore of the shunt to produce a distal fluid collection suitable for use with the ultrasound probe.

[0061] The ultrasound probe (20) is inserted into the central internal bore of the ventricular shunt tube (10) to stiffen it. The probe's fin is then inserted into the lateral internal bore of the ventricular shunt to prevent misalignment until locking by the proximal fixation system. The final assembly features the ultrasound transducer embedded in the tip of the ventricular shunt tube, with a fluid interface ensured by prior instillation of saline solution. This assembly allows for the acquisition of information about the environment surrounding the tip of the tube (10) and guides the operator's movements. The screw thread is locked before the assembly is inserted into the cerebral parenchyma. This locking is achieved by visual inspection of the markers on the surface of the ultrasound probe and the tube, as well as by direct visual inspection in one variant.The operator places the tip of the ventricular dialysis (VD) probe on the surface of the cerebral parenchyma and visualizes the ventricular target. This is usually the frontal horn of an ipsilateral lateral ventricle for external ventricular dialysis (EVD), and the ipsilateral ventricular trigone for peripheral ventricular dialysis (PVD). Once located, the operator gradually advances the probe through the cerebral parenchyma, under continuous ultrasound guidance, until the target is reached.

[0062] The ultrasound probe (20) is then removed from the tube (10) by unscrewing the proximal thread and sliding the fin into the internal bore of the shunt, freeing the lumen of the EVD drain and allowing immediate CSF reflux through its proximal end. The suction mechanism can rely solely on gravity. To achieve this, the fluid collection bag must be positioned below the head to create a siphon effect.

[0063] At the end opposite the perforated end (12), a suction system with a tubing connection tip (Micro Vac type, Elite Surgical Supplies) is screwed into the EVD catheter to ensure a secure connection, reducing the risk of disconnection and the risk of infection associated with this complication. The resulting negative pressure is adjusted to the clinical context, generally 1 bar. In the case of a VPD, the drainage system is connected to a flow-regulating drainage valve, and the entire system is continued via the abdominal catheter, which is located either in the peritoneum or in the vascular system at the level of the vena cava.

[0064] The volume of CSF that is thus extracted from the skull allows for the control and treatment of severe intracranial hypertension, thereby avoiding the multiple complications it induces.

[0065] In the case of ventriculoperitoneal (VP) or atrial (AAV) shunting, a retroauricular skin incision is made, and a 2- to 3-cm burr hole is created. The dura mater is coagulated and then incised. The ultrasound stylet is loaded into the VP catheter. The operator positions the tip of the ultrasound stylet assembly, inserted into the VP catheter, against the surface of the cerebral parenchyma and visualizes the ventricular target. This usually corresponds to the ventricular trigone. Once located, the operator gradually advances the stylet assembly through the cerebral parenchyma, under continuous ultrasound guidance, until the target is reached. The ultrasound stylet is then withdrawn, freeing the lumen of the VP catheter and allowing immediate CSF reflux through its proximal end. The assembly will be connected to a shunt valve and an abdominal or atrial catheter. OUTER DIAMETER OF THE TUBE

[0066] For drainage applications without intraventricular bleeding, a tube with an outside diameter of 1.5 to 1.9 millimeters is preferred.

[0067] For drainage applications with intraventricular bleeding, a tube with an outside diameter of 2.5 to 5 millimeters, and preferably less than 4 millimeters, should preferably be chosen. TUBE TIP CONFIGURATION

[0068] Figures 7A to 7G illustrate different embodiments of the deformable tip of the tube (10). It can have: A slightly concave end with a frontal skin of roughly constant thickness ( figure 7A ) to form a hollow, convex front end. A conical end with a front skin of substantially constant thickness ( figure 7B ) to form a hollow pointed end. A conical end with a flat transverse base ( figure 7C ) to form a solid pointed end

[0069] There figure 7D illustrates the height a of the solid and deformable tip, between 0.7 mm and 7 mm.

[0070] The wall thickness n of the tube (10) is approximately 0.7 mm and the internal bore is between 1.9 and 3 mm ( figure 7E ).

[0071] The outer diameter of the tube (10) is between 1.9 and 4 mm.

[0072] There figure 7F illustrates a variant where the tube wall (10) has a groove (17) forming a bore with a depth less than the wall thickness, i.e., less than 0.7 mm. Optionally, the wall thickness is increased at the groove.

[0073] This bore allows a transechoic liquid to be injected into the bottom of the tube (10).

[0074] THE figures 8A to 8CThey illustrate the tube (10) with a solid, deformable tip, and optionally a groove for injecting a transechoic liquid before the introduction of the stylet carrying an ultrasonic transducer at its distal end. This liquid can be introduced via the lateral bore (17) or via the central bore.

[0075] THE Figure 8D to 8G illustrate the tube (10) with a hollow and deformable tip, and optionally (figure 7G) a groove (17) for injecting a transechoic liquid under the stylet carrying at its distal end an ultrasonic transducer, circulation taking place through the internal lumen (18) ( figure 8E ). Instillation of the transechoic fluid

[0076] According to one method of use, the liquid is introduced into the tube before the insertion of the ultrasound stylet, so that the probe comes into contact with the liquid filling the internal volume of the hollow tip.

[0077] According to a second mode of use, the ultrasound stylet is introduced into the tube, and then liquid is injected into the tube through a longitudinal bore (17) formed in the wall of the tube (10).

[0078] According to a third variant, the ultrasound stylet is introduced into the tube and then transechoic liquid is injected into the internal volume of the probe tip via a syringe whose needle passes through the wall of the tube (10). Ventricular shunt system

[0079] THE figures 9 to 11 illustrate the invention and present the ventricular shunt probe alone ( figure 9 ), the ultrasound probe alone ( Figure 10 ) and the stylet engaged in the ventricular shunt lead ( figure 11 ).

[0080] The probe (10) has a section (30) with a thicker wall on the side of the stylus (20) insertion opening and / or made of a more rigid material than the probe (10). The edge of the open end of the probe has a visual marker (31) providing an angular reference. The section (30) has an internal thread (35) for attaching the stylus (22), which has a complementary thread (36). This thread (35) also allows for the subsequent attachment of a liquid drainage bag.

[0081] The probe (10) has a weakening groove (40) which optionally allows the upstream part of the probe (10) to be sectioned.

[0082] The stylus (22) also has a visual marker (33) allowing verification of the angular orientation of the stylus relative to the probe (10) and its correct angular alignment, as well as the direction of observation.

[0083] The base of the tip (11) contains transechoic fluid (36) which provides the interface between the ultrasound probe and the shunt tube (10). The stylet (20) protrudes slightly from the thickened section (30) of the shunt tube (10).

[0084] According to one variant, the parietal thickening is asymmetrical.

Claims

1. Cerebrospinal fluid drainage system for ventricular drainage, comprising an EVD or VPS probe consisting of a flexible tube (10) and a stylus (20) provided at its distal end with an ultrasound transducer (21), which can be inserted into the tube (10), and an echograph comprising a screen for displaying an anatomical image calculated in B-mode as a function of the signals supplied by the ultrasound transducer (21), - the stylus (20) comprises a rigid tube with an outside diameter corresponding to the inside diameter of the tube (10), the rigid tube containing only the supply wires of the ultrasound transducer (21), excluding an optical fiber, the rigid tube provided at its distal end with a transducer (21) of a diameter identical to the diameter of the tube (10) and having an imaging depth in the axis of the tube (10), the stylus comprising a proximal securing system of the complex, characterized in that the distal end of the tube (10) is closed by a closed, deformable hollow tip (12) forming a pocket for receiving a transechogenic liquid.

2. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the tube (10) has a thread (36) for the temporary engagement of an ultrasound stylus.

3. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the echograph provides B-mode ultrasound imaging associated with at least one other imaging modality comprising color mode, pulsed Doppler, power and 3D mode.

4. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the transducer is a scanning transducer.

5. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that it further comprises a sterile enclosure surrounding the stylus (20), the end of which, in which the transducer (21) is engaged, contains an ultrasound gel.

6. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the distal bottom of the tube (10) has a shape complementary to the outer shape of the transducer (21).

7. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the tip has a conical shape.

8. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the tip has a hemispherical shape.

9. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that it further comprises a computer executing a computer program for preprocessing the signal supplied by the scanning transducer, the preprocessing consisting in applying compensation for variations in the propagation conditions in the tip (12) of the tube (10).

10. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the tip of the probe comprises an echogenic marker.

11. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that a securing system makes it possible to unite the assembly of the two elements and to produce a stable fluid space at the distal end of the ultrasound probe.

12. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the internal part of the drain tube has an optimum bore for fluid flow in order to create an environment that is conducive to the use of the ultrasound probe at its distal internal part.

13. Cerebrospinal fluid drainage system for ventricular drainage according to claim 1, characterized in that the proximal end of the drain tube comprises a connector for joining the drain tube and the drainage system consisting of a tube and a collection bag.