External ventricular drain probe and ultrasonic stylus composite for an arrangement induced by continuous imaging

Abstract

The present invention relates to an external ventricular drain surgical device intended to drain cerebrospinal fluid transiently (EVD: external ventricular drain) or continuously (e.g., VPS ventriculoperitoneal shunt) using a drain implanted in the ventricle and connected to a drainage system when cerebrospinal fluid cannot circulate freely. The present invention relates to both EVD and VPS probes and their use during the placement process for treating acute or chronic hydrocephalus and therefore ventricular dilation. The present invention is industrially applicable in the medical field, particularly in the surgical field.

Description

Detailed Description of the Invention

[0001] (Technical Field of the Invention) The present invention relates to a ventricular drainage surgical device for transiently (EVD: external ventricular drain) or permanently (e.g., VPS, ventriculo-peritoneal shunt) draining cerebrospinal fluid, which is implanted in the ventricle and uses drainage connected to a drainage system when the cerebrospinal fluid cannot freely circulate, for a surgical device present in the cranial cavity. The present invention relates to both EVD probes and VPS probes for treating acute or chronic hydrocephalus and thus ventricular dilation, as well as their use during the placement process. The present invention is industrially applicable in the medical field, particularly in the surgical field.

[0002] Hydrocephalus is a condition that responds to abnormal accumulation of body fluids within the ventricular system, increasing the volume of the latter and thus intracranial pressure. Ventricular drainage is performed using a catheter to control intracranial pressure by draining cerebrospinal fluid (CSF), thereby reducing intracranial pressure.

[0003] The EVD probe typically consists of a silicone resin ventricular drainage catheter and is placed on a rigid guide wire used by a surgeon to implant the EVD probe into the patient's ventricular system. A small hole is made in the skull (burr hole), the EVD probe is inserted through the dura mater and then into the brain, and the brain parenchyma is fixed to the target ventricle.

[0004] Freehand placement of the EVD probe requires the neurosurgeon to estimate the three-dimensional position of the target ventricle, usually based on external anatomical landmarks. The ventricles are typically 0.5 - 3 cm in diameter and can be located at a depth of field of 5 - 50 millimeters, preferably 4 cm or more. Once the position of the target ventricle is estimated, the EVD catheter is pushed through the brain to the target ventricle. The freehand method does not provide a way to account for potential irregularities in the patient's anatomical structure that are not obvious from the outside. Factors such as intracranial expansive lesions (hematomas, edema, tumors, etc.), residual porencephalic cavities, genetic variations, etc. can also affect the position of the target ventricle.

[0005] The "intuitive" placement of a catheter sometimes requires the operator to make multiple attempts, and to achieve the necessary placement of an EVD catheter, the brain tissue will have to be traversed two or more times.

[0006] According to the literature, up to 65% of the placed ventricular drainage probes have distal ends in non-optimal positions (outside the optimal ventricular target). Of these, approximately one-third are non-functional and require revision and reintegration. Complications that may be associated with misplacement of an EVD catheter can include intracerebral hemorrhage, stroke, damage to adjacent brain structures, as well as the need for repeated procedures to replace a misplaced catheter. It has also been reported that the infection rate increases when multiple attempts at EVD placement are necessary.

[0007] Several solutions have been explored, in particular, catheter positioning using an imaging system outside the skull (ultrasound on the surface of the brain parenchyma parallel to an EVD probe that requires a second burr hole, a stereotactic state, or a brain scanner induced by virtual reality), the use of a GHAJAR guide to constrain positioning relative to the surface of the skull, and the use of an ultrasonic stylet introduced into the drain to provide depth information by a linear ultrasound that guides the user to the ventricle.

[0008] (Prior art) Known in the prior art is a shunt device implantable for draining cerebrospinal fluid from the subarachnoid space of a patient, comprising a shunt having first and second opposing ends, the second end being adapted to penetrate the wall of the patient's S-shaped, transverse, straight, or sagittal venous sinus, a check valve, a hollow passage extending between the second end and the check valve such that cerebrospinal fluid is discharged from the second end and can be discharged through the valve, and a mechanism coupled to the shunt and adapted to anchor the shunt at a desired position near the subarachnoid space. Patent WO2015108917 describes a shunt device comprising the above components.

[0009] Dual-orientation 16MHz single-element ultrasonic needle transducer 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 paper concerns the incorporation of ultrasonic devices into the type of biopsy needles commonly used as intervention tools to provide feedback to neurosurgeons during surgical procedures. A single-element transducer facing forward or laterally is used to identify the most appropriate path for accessing the target tissue site.

[0010] In the field of spinal puncture, which enables the collection of cerebrospinal fluid (CSF) samples from the spine rather than within the cranial cavity on occasion, patent application WO2017192603 relates to a needle delivery system comprising a needle and an ultrasonic transducer element attached to the distal end of the needle. The system also comprises a needle restraint assembly configured to accept and constrain the needle only within a range of angular movement for rotational freedom. The system also comprises an ultrasonic data processor configured to communicate with the transducer element to receive ultrasonic detection signals and with a needle sensor system to receive needle angle orientation signals.

[0011] This prior art solution relates to procedures performed by emergency physicians or neurologists to obtain cerebrospinal fluid (CSF), an important fluid in the diagnosis of many diseases and conditions of the central nervous system (CNS). To perform this procedure, the physician palpates the lower back and identifies the L3-L5 vertebrae. Once identified, the physician proceeds to insert a needle, usually a Quincke needle, and apply a local anesthetic before advancing.

[0012] This solution is not suitable for the operation of implanting a drain into the ventricle, which is intended to be connected to a drainage system when the cerebrospinal fluid cannot circulate freely.

[0013] (Disadvantages of the prior art) The prior art solution only provides depth information in a one-dimensional mode that explores only a single line that is the axis of the ultrasonic probe, so it is not fully satisfactory. This information is only partially useful to the physician regarding the relevance of the pointer and the orientation of the probe. They are designed to minimize the cross-section so that they can pass through a thin drainage catheter with a cross-section of less than 1.7 mm.

[0014] To utilize the information provided by the prior art solution, the operator has to learn to interpret it, which requires a significant amount of time before being able to interpret it reflexively during the procedure.

[0015] (Disclosure of the invention) The present invention aims to overcome the disadvantages of the state of the art by means of a cerebrospinal fluid drainage system comprising an EVD probe and an ultrasonic stylet insertable into said EVD probe, said ultrasonic stylet comprising a rigid tube provided at its distal end, and the scan converter being characterized in that its axis forms a ray directed along the longitudinal axis of the ultrasonic stylet.

[0016] In its broadest sense, the present invention relates to a cerebrospinal fluid drainage system comprising an EVD or VPS probe as claimed in claim 1.

[0017] It consists of an echograph comprising a flexible tube having an outer diameter of 1.9 to 5 millimeters, a stylet with an ultrasonic transducer attached to its distal end, and a display screen having an image calculated as a function of the signal provided by said ultrasonic probe and insertable into said tube: - The stylus includes a rigid tube having an outer diameter corresponding to the inner diameter of the tube that includes only the supply wire of the transducer. Except for the optical fiber, at its distal end, the rigid tube includes a transducer having the same diameter as that of the rigid tube, and has an image depth along the axis of the rigid tube of 0 to 100 millimeters. - The distal end of the tube (10) is closed by a solid and deformable tip (12). - The proximal end of the tube (see Figure 6) has a fixing system having the proximal end of the ultrasonic probe. This fixing system has five purposes, namely, (1) restricting the longitudinal collision of the ultrasonic stylus within the VD tube during its insertion, (2) restricting the rotation between the tube (10) and the ultrasonic stylus, (3) fixing the insertion depth of the stylus within the tube, (4) creating a fixing system between the ultrasonic stylus and the drain to prevent the mobility of one or the other of the two elements of the assembly, and (5) generating a fluid space at the distal end of the ultrasonic probe useful for its use. - The fixing system may be of the screw, bayonet, anchor, Velcro (registered trademark), or notch type, and this list is non-limiting. In a variant, the proximal end of the tube supporting the fixing system is reinforced from its functional part and is detachable. The removable part may be pre-perforated or may be sectioned during the operation using a cutting device such as a scalpel or medical scissors. Preferably, this removable part is transparent so that the correct attachment of the assembly can be visually confirmed. In another variant, the fixing part is a thread (Hyu-lock type) and is non-removable, facilitating and fixing its connection to the collection tubing and its pocket (Figure 6), thus making it possible to limit mismatches compared to conventional interlock systems.

[0018] In a variant, the tube has one or more internal transverse bores with a longitudinal axis that is larger and complementary to the central hole. Some or all of these bores respond to the complementary shape of the ultrasonic stylet (in the form of segment fins or longitudinal blades) in order to maximize the bonding of the ultrasonic stylet and limit the degree of rotation of the distal end of the assembly. Alternatively, one or more of these bores advantageously enable the injection of a trans-echo generating fluid, such as physiological serum, from the proximal end of the assembly, into the interface between the piezoelectric element of the ultrasonic stylet and the inner surface of the tip of the VD tube.

[0019] The cross-section of the tube is circular. Alternatively, the cross-section of the tube is asymmetric and thickens adjacent to the lateral internal bore (Figure 6) in order to maintain a satisfactory resistance to bending after removal of the ultrasonic stylet.

[0020] The ultrasonic stylet and optionally the VD tube present a proximal visual marker, enabling the orientation of the ultrasonic probe to be known and facilitating the spatial position of the operator during the substantial insertion of the assembly.

[0021] The system provides a B-mode ultrasound image.

[0022] According to a variant, the echograph provides a B-mode ultrasound image associated with at least one other image modality including color mode, pulsed doppler, power, and 3D mode. Advantageously, the transducer is a scanning transducer.

[0023] According to a variant, the system further comprises a sterile enclosure surrounding the stylet and containing an ultrasonic gel at the end where the transducer is engaged.

[0024] According to another variant form, the distal bottom of the tube has a shape complementary to the external shape of the transducer.

[0025] According to the first embodiment, the tip has a conical shape. According to another embodiment, the tip has a hemispherical / alternative shape for the purpose of limiting the generation of optical aberration due to the deflection of the ultrasonic beam it generates (which ultimately causes ultrasonic artifacts).

[0026] The tip and / or the whole of the EVD tube is made of a biocompatible material having biomechanical properties similar to those normally expected of a drainage probe, and preferably made of a material having as low an attenuation coefficient as possible for the ultrasonic beam. The thickness of this tip can be advantageously reduced for the same purpose.

[0027] Advantageously, the tip contains ultrasonic gel or drip-sterilized water. This drip injection can be carried out by pre-immersing the VD tube in the area of physiological serum before the ultrasonic scanner-tube assembly, or by its drip injection through the internal lumen of the tube. In a variant, the assembly is fixed and the forward installation is carried out by means of a lateral internal hole or by direct puncture using a needle from the conical tip of the VD tube.

[0028] According to a variant, the system further comprises a computer that executes a computer program for preprocessing the signal supplied by the scanning transducer, and the preprocessing consists of applying compensation for fluctuations in the propagation conditions at the tip of the tube.

[0029] Preferably, the operating frequency of the transducer is 4Mhz to 15Mhz, more preferably 10Mhz.

[0030] According to a variant, the tip of the probe is provided with an echo-generating marker.

[0031] (Brief Description of the Drawings) Other features and advantages of the present invention will become apparent by reading the following detailed embodiments with reference to the accompanying drawings, each showing. [Figure 1] Figure 1 shows a cross-sectional view of the system according to the present invention. [Figure 2] Figure 2 is a view showing the end of the probe according to the first embodiment. [Figure 3] Figure 3 is a view showing the end of the probe according to the second embodiment. [Figure 4] Figure 4 shows a cross-sectional view of the end of the probe according to the third embodiment. [Figure 5] Figure 5 shows a cross-sectional view of the end of the probe according to the fourth embodiment. [Figure 6A] Figure 6A shows a view of the stylus according to the first position. [Figure 6B] Figure 6B shows a view of the stylus according to the second position. [Figure 6C] Figure 6C shows a view of the stylus according to the third position. [Figure 7A] Figure 7A shows a cross-sectional view of the first variant of the geometry of the tube according to the present invention. [Figure 7B] Figure 7B shows a cross-sectional view of the second variant of the geometry of the tube according to the present invention. [Figure 7C] Figure 7C shows a cross-sectional view of the third variant of the geometry of the tube according to the present invention. [Figure 7D] Figure 7D shows a cross-sectional view of the fourth variant of the geometry of the tube according to the present invention. [Figure 7E] Figure 7E shows a cross-sectional view of the first variant of the tube according to the present invention. [Figure 7F] Figure 7F shows a cross-sectional view of the first variant of the tube according to the present invention. [Figure 7G] Figure 7G shows a cross-sectional view of the second variant of the tube according to the present invention. [Figure 8A] Figure 8A shows a cross-sectional view of the tube according to the present invention having a solid tip. [Figure 8B] Figure 8B shows a cross-sectional view of the tube according to the present invention having a solid tip after introduction of the trans-echogenic source fluid. [Figure 8C] Figure 8C shows a cross-sectional view of the tube according to the present invention having a solid tip after introduction of the fluid and the ultrasonic stylus. [Figure 8D] Figure 8D shows a cross-sectional view of the tube according to the present invention having a hollow tip. [Figure 8E] Figure 8E shows a cross-sectional view of the tube according to the present invention having a hollow tip after introduction of the trans-echogenic source fluid. [FIG. 8F] FIG. 8F shows a cross-sectional view of a tube according to the present invention having a hollow tip after introducing a fluid through a groove after introducing an ultrasonic stylus. [FIG. 8G] FIG. 8G shows a cross-sectional view of a tube according to the present invention having a hollow tip after introducing a fluid and an ultrasonic stylus. [FIG. 9] FIG. 9 shows a cross-sectional view of a tube according to the present invention. [FIG. 10] FIG. 10 shows a cross-sectional view of an ultrasonic stylus. [FIG. 11] FIG. 11 shows a cross-sectional view of a system formed by a stylus engaged with a ventricular drain tube. (Description of Embodiment)

[0032] The present invention relates to a system comprising an EVD or VPS probe constituting a drainage tube (10) and an ultrasonic stylus (20) for related injection.

[0033] The outer diameter of the drainage tube (10) is typically 1.9 millimeters to 5 millimeters, and the inner diameter is 1.7 millimeters to 3.5 millimeters. The outer diameter of the stylus (20) is typically 0.5 millimeter smaller than the inner diameter of the drainage tube and has a central channel for the passage of an electrical wire connecting the transducer to an ultrasonic system.

[0034] The thickness of the tip at the distal end of the tube is 1 to 7 mm depending on the output of the ultrasonic probe and the shape of the tip. This tip is solid or, more preferably, has an elliptical or square central hole that conforms to the surface of the Doppler stylus. In the assembly, this hole is of the largest elliptical, conical, pyramidal, or square shape, or a similar shape, for accommodating the Doppler stylus - flexible enclosure composite. For example, it may be a silicone resin, a silicone resin-based material, i.e., a silicone resin-based material containing at least 10% silicone resin, rubber, plastic, polyamide, polyether block amide, polycarbonate, polyimide, or polytetrafluoroethylene, and this list is non-exhaustive.

[0035] The drainage tube (10) is perforated distally and laterally with a plurality of holes (12) having a diameter of approximately 2 mm over a span of approximately 20 mm. These openings may be fine holes, holes, orifices, or slots and pass through the membrane of the tube (10). These openings are preferably sized to permit the passage of water, cerebrospinal fluid, and blood. The pores, holes, orifices, or slots may be adapted according to their ability to allow cerebrospinal fluid to flow and may have variable shapes that can be cylindrical, conical, or elliptical, and this list is not exhaustive. The distance between the holes is variable in the range of 1 to 4 mm to allow for proper flow of cerebrospinal fluid.

[0036] The end forms a conical or pyramidal or elliptical tip (11) and is non-rigid. This tip is solid and has a proximal inner bore that conforms to the shape of the distal end of the ultrasonic probe, but may have an inner bore shaped to receive a flexible enclosure - Doppler stylet complex or a fluid interface.

[0037] The flexible drainage tube (10) is intended to be implanted in a patient for a short or long period of time to drain the ventricular system in cases of acute or chronic hydrocephalus. This tube (10) is connected to a gravity drainage system using a collection bag in the case of an EVD and is connected to a drainage system connected to the peritoneal or vascular system in the case of a VPS. In the case of a VPS, the flexible drainage tube has the same characteristics at its distal portion (tip, holes, pores, or drainage orifice). The intracranial length is 4 to 9 cm at a right angle, allowing the use of a reservoir to apply the tube to the cranial cavity and continued by a drainage tube connected to a bypass valve. The junction region between the drain and the ultrasonic stylet can be cut to connect to the valve.

[0038] The channel of this drainage tube (10) enables it to accommodate an ultrasonic stylus (20) formed by a removable rigid mandrel whose length exceeds that of the drainage tube (10), facilitates the introduction of the device into the brain parenchyma, and facilitates its removal after the placement of the EVD / VPS probe. This ultrasonic stylus comprises a scanning ultrasonic transducer (21) powered by a wire (22). This is an Aloka UST 534 type transducer for the embodiment. This ultrasonic stylus is inserted into the drainage tube along the bore area using fins, and its final position is locked by a proximal fixing system to fix the assembly and create a distal fluid space useful for the operation of the ultrasonic probe. The introduction of the assembly is directed according to the marker of the ultrasonic stylus indicating the orientation of the ultrasonic beam and its front part.

[0039] The active element of the transducer mainly consists of a piezoelectric material, optionally a piezoelectric composite, optionally multilayer, and a set of at least two electrodes capable of generating an electric field across the thickness of the piezoelectric material. Preferably, one or more acoustic matching layers are integrated into this active element on the front of the active element to facilitate acoustic transmission to the front of the transducer.

[0040] The transducer is preferably adhered to the distal end of the stylus (20) by an epoxy adhesive.

[0041] This transducer may be composed of a network of piezoelectric micro transducers or a single transducer driven by a vibrating motion by a MEMS type support. It delivers a 2D or 3D signal of the environment in front of the conical tip (11) to enable the operator to guide the advancement and orientation of the rigid mandrel during the installation of the drain through the patient's brain parenchyma. The signal is used by a 2D ultrasonic scanner in B-mode to provide an image of the area in front of the probe.

[0042] The operating frequency is typically 10 MHz. The transducer (21) is connected to the echograph. This ultrasonic device must have a "B" ultrasonic mode (2D anatomical image) and, optionally, may involve a "C" mode (color), "D" mode (Doppler), power mode, and / or 3D mode, with an image depth of 0 - 50 - 100 millimeters. The ultrasonic probe is preferably linear, curved, or microconvex, but can be compatible with any type of ultrasonic probe that enables obtaining a B-mode ultrasonic image along the longitudinal axis of the stylus (such as a suitable IVUS-type microprobe (intravascular), trapezoidal probe, etc.).

[0043] The signal supplied by the transducer can be corrected by a computer that applies digital processing to compensate for fluctuations in transmission induced by the material constituting the tip (11) and thickness variations according to the angle of the shot in the case of non-uniformity at the tip (11).

[0044] (Chip configuration) Figures 2 - 5 show different configurations of the tip (11) of the flexible tube (20). It may be conical as shown in Figure 2 or hemispherical as shown in Figure 3.

[0045] The distal end of the ventricular drain is produced, to the extent possible, within a biocompatible material of trans-echogenic properties so as to be as non-invasive as possible.

[0046] Its thickness and geometric structure are aimed at reducing optical aberration artifacts and attenuation of the ultrasonic beam. It can also receive an ultrasonic gel (15) housed between the probe (21) and the inside of the tip (11), as shown in Figure 4 or 5.

[0047] The sterilizing ultrasonic gel is attached to the tip of the ultrasonic stylus by a sterilizable flexible enclosure (16) to produce a flexible enclosure - Doppler stylus composite that is loaded within the drain probe. In this variant, the inner diameter of the EVD probe is slightly larger than the outer diameter of the flexible enclosure - Doppler stylus composite (Figure 2). The length of the flexible enclosure is such that once it spreads out on the Doppler stylus, it always remains less than the length of the Doppler stylus (about 6 - 20 cm) and extends beyond the surface of the cranial cavity.

[0048] Alternatively, a trans - echo generating fluid such as saline is directly injected into the transducer - chip interface of the drain tube. This infusion can be carried out before or after the assembly of the tube - ultrasonic stylus composite, by means of the inner bore of the tube that is complementary to the central hole receiving the stylus, or by directly puncturing using a fine needle from the space behind the tip of the tube. Thus, in these variants, the length of the portion of the ultrasonic stylus inside the drain tube is slightly shorter than the inner bore of the tube to create this fluid space that is useful for the use of the ultrasonic probe.

[0049] Optionally, the tip of the probe includes a trans - echo generating marker intended to form a visual reference on the transcranial ultrasonic image.

[0050] (Configuration of the proximal part) Figure 6 shows the male and female thread pitches between the ultrasonic probe and the drain tube, enabling the connection between the two components. Once locked, the threads (1) limit the longitudinal insertion of the VD tube during its insertion, (2) limit the rotation between the tube (10) and the ultrasonic stylet, (3) fix the insertion depth of the stylet into the tube, (4) create a system fixed between the ultrasonic stylet and the drain to prevent the mobility of one or the other of the two elements of the assembly, and (5) enable the generation of a distal fluid space of the ultrasonic probe useful for its use. This last point ensures the presence of a tight fluid space at the tube / ultrasonic interface regardless of the movement imparted to the assembly at the distal end of the assembly (Figure 6).

[0051] Alternatively, the thread of the drain tube enables its connection to the collection tube and the pocket (X), limiting the risk of inconsistency with conventional interlock systems. In another variant, the fixing system is present on the most proximal segment of the tube and is removable during surgery.

[0052] (Configuration of the front tube part) Figures 6A - 6C show the front of the elliptical tube with a thicker front having grooves inside it, enabling the fins of the ultrasonic probe to be received to avoid incorrect paths and fix the introducer part.

[0053] On its outer front part, there are markings indicating the orientation of the ultrasonic probe and the introduction direction into the brain parenchyma (Figure 6).

[0054] (Implementation of the invention) Using anatomical landmarks, a punctate skin opening is created in front of the coronal suture, 2 cm or 3 cm laterally from the midline. Then, a burr hole with a diameter of about 5 mm to 3 cm is drilled, and sometimes the dura mater is coagulated.

[0055] To generate distal fluid collection suitable for use with an ultrasonic probe, sterile water is dripped with a syringe along the inner bore of the drain.

[0056] The ultrasonic stylet (20) is engaged with the central inner bore of the tube (10) of the VD probe and reinforced by inserting the fins of the ultrasonic probe into the outer inner bore of the ventricular drain to avoid incorrect directions until locked by the proximal fixation system. In the final assembly, the ultrasonic transducer is embedded at the tip of the ventricular drain tube having a fluid interface ensured by prior instillation of saline. This assembly enables obtaining information about the environment of the tip of the tube (10) and directing the operator's gestures. The screw pitch lock is performed before inserting the assembly in contact with the brain parenchyma, by visual control of the markers on the surface of the ultrasonic stylet and the tube, and by direct visual control in the variant. The operator places the tip of the VD probe on the surface of the brain parenchyma and visualizes the ventricular target. Usually, it corresponds to the frontal horn of the ipsilateral ventricle in the context of EVD, and to the ipsilateral ventricular junction of VPS. Once spotted, the operator gradually pushes the composite through the brain parenchyma under continuous ultrasonic guidance until reaching the target.

[0057] The ultrasonic stylet (20) is then withdrawn from the tube (10) by loosening the proximal threads, sliding the fins within the inner bore of the drain, releasing the lumen of the EVD drain, and enabling immediate backflow of CSF by its proximal end. The suction mechanism may be based only on gravity. For this purpose, the fluid collection pocket must be placed under the head to obtain a siphon effect.

[0058] At the end opposite the perforated end (12), a suction system with a connection end piece to a tube (Micro Vac type, Elite Surgical Supplies) is screwed onto the EVD probe, enabling a secure connection, reducing the risk of misadjustment, and reducing the risk of infection inherent in this complication. The depression generated is adapted to the clinical situation, generally 1 bar. In the case of VPS, the drainage system is connected to a drainage valve that regulates the flow and is entirely continued by an abdominal catheter located either in the peritoneal or the great venous vascular system. Thus, the volume of CSF extracted from the cranial cavity makes it possible to control and treat severe intracranial hypertension and thus avoid the multiple complications it induces.

[0059] When performing a ventriculo-peritoneal shunt (VPS) or a ventriculo-atrial shunt (VAS), a posterior auricular skin incision is made and a 2 - 3 cm burr hole is created. The dura mater is coagulated and then incised. The ultrasonic stylet is loaded into the VPS probe. The operator places the tip of the ultrasonic stylet complex inserted into the VPS probe on the surface of the brain parenchyma to visualize the ventricular target. Usually, it corresponds to the ventricular junction. Once spotted, the operator gradually pushes the complex through the brain parenchyma under continuous ultrasonic guidance until the target is reached. Then, the ultrasonic stylet is withdrawn, freeing the lumen of the VPS catheter and allowing immediate backflow of CSF through its proximal end. The assembly is connected to a bypass valve and an abdominal or atrial catheter.

[0060] (Tube outer diameter) For drainage applications without intraventricular hemorrhage, it is preferable to select a tube with an outer diameter of 1.5 - 1.9 millimeters.

[0061] For drainage applications with intraventricular hemorrhage, a tube with an outer diameter of 2.5 - 5 millimeters, preferably less than 4 millimeters, is preferably selected.

[0062] (Tube tip configuration) Figures 7A-7G show different possible embodiments of the deformable distal end of the tube (10).

[0063] - A slightly concave end (Figure 7A) with a front skin of substantially constant thickness forms a domed hollow front end. - A tapered end (Figure 7B) with a front outer plate of substantially constant thickness to form a hollow pointed end. - A tapered end (Figure 7C) with a planar lateral bottom forms a solid pointed end. Figure 7D shows the height a of the solid deformable tip, which is included between 0.7 mm and 7 mm.

[0064] The wall thickness n of the tube (10) is about 0.7 mm, and the inner bore is 1.9 - 3 mm (Figure 7E). The outer diameter of the tube (10) is 1.9 - 4 mm.

[0065] Figure 7F shows a variant where the wall of the tube (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 in the groove.

[0066] This hole enables the injection of the trans - echo - generating fluid at the bottom of the tube (10).

[0067] Figures 8A - 8C show a tube (10) with a solid deformable tip and, optionally, a groove for injecting the trans - echo - generating fluid before the introduction of a stylet carrying an ultrasonic transducer at its distal end. This fluid can be introduced through the lateral bore (17) or through a central hole.

[0068] Figures 8D - 8G show a tube (10) with a hollow deformable tip and, optionally (Figure 7G), a groove (17) for injecting the trans - echo - generating fluid under a stylet carrying an ultrasonic transducer at its distal end, and the circulation is carried out through the internal lumen (18) (Figure 8E).

[0069] (Droplet of the Trans-Echo Generating Fluid) According to the first embodiment, the fluid is introduced into the tube before the ultrasonic stylus is inserted, so that the probe contacts the fluid filling the internal volume of the hollow tip. According to the second embodiment, the ultrasonic stylus is introduced into the tube, and then the fluid is injected into the tube through the longitudinal bore (17) formed in the wall of the tube (10).

[0070] According to the third modification, the ultrasonic stylus is introduced into the tube, and then the trans-echo generating fluid is injected into the internal volume of the probe tip by means of a syringe, and the syringe needle passes through the wall surface of the tube (10).

[0071] (Ventricular Drainage System) Figs. 9 to 11 show the present invention, showing only the ventricular drain probe (Fig. 9), only the ultrasonic stylus (Fig. 10), and the stylus engaged with the ventricular drain probe (Fig. 11).

[0072] The probe (10) has a portion (30) with a thick wall on the side of the opening for introducing the stylus (20), and / or is made of a material that is more rigid than the material of the probe (10). The edge of the open end of the probe has a visual marker (31) for providing an angular reference. The section (30) has an internal thread (35) for fixing the stylus (22) having complementary threads (36). This thread (35) also makes it possible to fix the fluid drain pocket.

[0073] The probe (10) optionally has a weakened groove (40) that allows the upstream portion of the probe (10) to be cut off.

[0074] The stylus (22) also has a visual marker (33) that makes it possible to check the angular direction of the stylus with respect to the probe (10) and its correct angular alignment, as well as the viewing direction.

[0075] The bottom of the tip portion (11) includes a transducer echo generating fluid (36) that provides an interface between the ultrasonic probe and the drain probe (10). The stylus (20) projects slightly from the thickened portion (30) of the drain tube (10).

[0076] According to a variant, the vertex hypertrophy is asymmetric.

Brief Description of the Drawings

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Claims

1. An EVD or VPS probe comprising a flexible tube (10) and a stylus (20) that can be inserted into the flexible tube (10) and has an ultrasonic transducer (21) at its distal end, An cerebrospinal fluid drainage system for a ventricular drain comprising an echograph including a screen for displaying an anatomical image calculated in B-mode as a function of a signal supplied by the ultrasonic transducer (21), The stylus (20) is a rigid tube that includes only the supply wire of the ultrasonic transducer (21) except for the optical fiber, and includes a rigid tube having an outer diameter corresponding to the inner diameter of the flexible tube (10), The rigid tube includes a transducer (21) having the same diameter as the diameter of the rigid tube at its distal end, The flexible tube (10) includes a tip (11), and the distal end of the flexible tube (10) is closed by the closed deformable tip (11), The cerebrospinal fluid drainage system for a ventricular drain, wherein the tip (11) is hollow and forms a pocket for receiving a trans-echogenic fluid.

2. The cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein the flexible tube (10) has a thread (35) for engagement with the stylus (20).

3. The echograph according to claim 1, characterized in that it provides a B-mode ultrasonic image related to at least one other image modality including a color mode, a pulsed doppler, a power and a 3D mode.

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

5. The cerebrospinal fluid drainage system for a ventricular drain according to claim 1, further comprising a sterile enclosure that surrounds the stylus (20) and the end where the transducer (21) is engaged contains an ultrasonic gel.

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

7. A cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein the tip has a conical shape.

8. A cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein the tip has a hemispherical shape.

9. Further comprising a computer that executes a computer program for preprocessing a signal supplied by the scanning transducer, The cerebrospinal fluid drainage system for a ventricular drain according to claim 4, wherein the preprocessing comprises applying compensation for fluctuations in propagation conditions at the tip (11) of the flexible tube (10).

10. A cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein the tip of the EVD or VPS probe includes an echo generating marker.

11. A cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein the fixation system integrates an assembly of two elements of the flexible tube (10) and the stylet (20) to generate a stable fluid space at the distal end of the EVD or VPS probe.

12. A cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein an inner portion of the flexible tube (10) has a bore for fluid flow.

13. A cerebrospinal fluid drainage system for a ventricular drain according to claim 1, wherein the proximal end of the flexible tube (10) comprises a connector for joining the flexible tube (10) to a drainage system composed of a tube and a collection bag.

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