Trocar for electromagnetic navigation with a ventriculoscope

Abstract

The present invention relates to a trocar for electromagnetic navigation with a ventriculoscope, comprising a base from which a rod protrudes, the base being shaped as a body of revolution configured to fit into the rear end of the tube of a sheath of a ventriculoscope, and the rod being cylindrical in shape with a rounded distal end for insertion through the tube of the sheath of a ventriculoscope. The invention is characterised in that it further comprises an open blind longitudinal hole at the proximal end of the base, said blind longitudinal hole being configured to receive a stylet of an electromagnetic navigation system.

Description

[0001] TROCAR FOR ELECTROMAGNETIC NAVIGATION WITH VENTRICULOSCOPE

[0002] DESCRIPTION

[0003] OBJECT OF THE INVENTION

[0004] The present invention belongs to the field of neurosurgery, and more particularly to the instruments used to access the ventricular cavity of a patient.

[0005] The object of the present invention is a new trocar specifically designed to allow electromagnetic navigation of a venculoscope during the procedure of accessing the cerebral ventricle of a patient.

[0006] BACKGROUND OF THE INVENTION

[0007] There are four anatomical cavities in the brain, called cerebral ventricles, which are interconnected and constitute the ventricular system through which cerebrospinal fluid circulates. Certain conditions, such as hydrocephalus, require access to the cerebral ventricles. A surgical instrument called a "ventriculoscope" is used for this purpose.

[0008] A ventriculoscope is a neurosurgical instrument designed for performing interventions in the ventricular cavities of the brain. Fig. 1A shows a ventriculoscope, in this case specifically the LOTTA model ventriculoscope manufactured by Karl Storz. As can be seen, the ventriculoscope (100) has a main tube (110) along which several ducts (not visible in the figure) extend that are used for vision, irrigation / suction, as well as for the introduction of specific instruments for each intervention. However, the tube (110) of the ventriculoscope (100), being traversed by the aforementioned ducts, has a tip with relatively sharp edges that are not ideal for moving it through brain tissue until reaching the ventricular space.

[0009] For this reason, in order to ensure that no damage is inflicted on the patient's brain tissue during the process of introducing the venculoscope into the ventricular cavity, the use of two auxiliary elements specifically designed for this purpose is known: the sheath and the trocar.

[0010] Fig. 1B shows an example of a sheath (200, top) and a trocar (300, bottom) used in conjunction with the aforementioned venticuloscope (100). The sheath (200) essentially comprises a hollow tube (210) with a diameter larger than the diameter of the tube (110) of the venticuloscope (100). As with the tube (110) of the venticuloscope (100), the edges of the distal end of the tube (210) of the sheath (200) are also not suitable for introduction through brain tissue, since they could cause tissue damage. The trocar (300), on the other hand, comprises a solid shaft (310) having a diameter smaller than the diameter of the tube (210) of the sheath (200) and a length slightly greater than the length of the tube (210) of the sheath (200). In addition, the tube (310) of the trocar (300) has an anatomically shaped distal end (320) formed by smooth curves.When the trocar (300) is inserted into the sheath (200), the tip of the tube (310) of the trocar (300) protrudes from the distal end of the tube (210) of the sheath (200).

[0011] The sheath (200) and trocar (300) are used in combination to facilitate the introduction of the tube (110) of the venculoscope (100) into the ventricular cavity. First, the trocar (300) is inserted into the sheath (200) until the anatomical distal end (320) of the tube (310) of said trocar (300) protrudes through the end of the sheath (200). The sheath (200) is then introduced into the patient's brain cavity until it reaches the ventricle using a suitable navigation system. Because the distal end (320) of the trocar is anatomical, tissue damage along the way is minimized. Once the sheath-trocar assembly has reached the ventricular space, the trocar (300) is removed and the tube (110) of the venculoscope (100) is introduced in its place. This procedure allows the venticuloscope (100) to be introduced into the surgical field in an atraumatic manner.

[0012] Until now, the navigation systems used for this purpose have been based on various techniques, including optical navigation or introduction based on real-time ultrasound images. Sometimes, the ventriculoscope tube is also introduced directly, even though the edges of the distal end of the tube are not suitable for this purpose. However, these navigation techniques present several drawbacks, making the use of electromagnetic navigation particularly desirable with this type of ventriculoscope.

[0013] DESCRIPTION OF THE INVENTION

[0014] The inventors of the present application have developed a modified trocar that allows the use of an electromagnetic navigation system during the ventriculoscope insertion process. Specifically, the trocar is designed for use in conjunction with the Karl Storz LOTTA ventriculoscope.

[0015] Electromagnetic navigation is advantageous over other navigation systems, such as optical navigation, for several reasons. For example, the reference structures that must be attached to the base of the navigated element make it difficult to operate. In any case, the main concept underlying electromagnetic navigation is the introduction of a well-known element called a stylet, which, through certain electromagnetic means, is visible in a medical image using a specially designed system.

[0016] Fig. 2 shows, by way of example, the Medtronic S8 Stealthsystem stylet. The stylet (400) essentially comprises a metallic needle (410) protruding from a flat circular body (420) which, in turn, is connected by a cable (430) to certain electronic means. The electromagnetic navigation system is designed so that the needle (410) is visible in real time through a medical imaging system.

[0017] Currently, the trocar used to introduce the ventriculoscope into the patient's ventricular cavity is not compatible with the use of an electromagnetic navigation system stylet.

[0018] The present invention solves this problem by modifying the trocar used to introduce the ventriculoscope. This modification consists of creating a longitudinal orifice open at the posterior end of the trocar and extending to a specific point along its length, but which, in any case, is not open at its distal end. This orifice is sized for the introduction of the EM stylet, such that the sheath—with the trocar housed inside, as described above—is introduced with the aid of the magnetic navigation system based on the EM stylet.

[0019] Thus, the object of the present invention is a trocar for electromagnetic navigation with a ventriculoscope. The trocar comprises a base from which a stem protrudes. The base is shaped like a body of revolution configured to fit into the rear end of the tube of a ventriculoscope sheath (preferably the Karl Storz LOTTA ventriculoscope). The stem is cylindrical with a rounded distal end for insertion through the tube of a ventriculoscope sheath (preferably the Karl Storz LOTTA ventriculoscope). The dimensions of the trocar of the invention are preferably 180 mm in length and 6 mm in diameter.

[0020] Thus far, the configuration of a trocar similar to that conventionally used to facilitate the introduction of a ventriculoscope (preferably a Karl Storz LOTTA model ventriculoscope) has been essentially described. However, the trocar of the present invention differs from that in that it also comprises a blind longitudinal orifice open at the proximal end of the base. This blind longitudinal orifice is configured to receive a stylet of an electromagnetic navigation system (preferably a Medtronic S8 Stealthsystem stylet).

[0021] Thanks to this configuration, it is possible to insert an EM stylet into the trocar's longitudinal orifice, thus facilitating electromagnetic navigation during the sheath-trocar assembly introduction process. This makes it possible to combine the advantages of using the sheath-trocar assembly for the introduction process with electromagnetic navigation.

[0022] The diameter of the trocar's blind longitudinal hole will be adapted to the diameter of the stylet to be housed inside. Preferably, the diameter of said hole is between 1.8 mm and 2.2 mm, even more preferably 2 mm.

[0023] The length of the trocar's blind longitudinal hole must also be adapted to the length of the stylet to be inserted inside. Preferably, the length of this hole is between 150 mm and 170 mm, and even more preferably 160 mm.

[0024] In principle, the trocar of the invention can be made of various materials, such as stainless steel or similar. However, in a particularly preferred embodiment of the invention, the trocar is manufactured using 3D printing. In this case, the material it is made of is polypropylene.

[0025] BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Fig. 1A shows an example of a prior art ventriculoscope, namely a Karl Storz LOTTA model ventriculoscope.

[0027] Fig. 1B shows a sheath (top) and trocar (bottom) used for insertion of the ventriculoscope tube of Fig. 1A.

[0028] Fig. 2 shows a stylet of an electromagnetic navigation system according to the prior art, namely the Medtronic S8 Stealthsystem stylet.

[0029] Fig. 3 shows a perspective view of the modified trocar according to the present invention.

[0030] Fig. 4 shows another perspective view of the modified trocar according to the present invention.

[0031] PREFERRED EMBODIMENT OF THE INVENTION

[0032] A particular example of trocar (1) according to the present invention is described below with reference to the figures.

[0033] The trocar (1) comprises a base (11) and a stem (12). The base (11) is a body of revolution configured to fit into the rear portion of the sheath (200) of a ventriculoscope (100) (specifically, the LOTTA ventriculoscope by Karl Storz). The stem (12) is a cylindrical body that fits inside the sheath (200) of the ventriculoscope (100). It is a cylindrical body of 6 mm in diameter and 180 mm in length provided with a rounded distal end (13). The base (11), in turn, has an approximate length of 15 mm.

[0034] The stem (12) is traversed by a blind longitudinal hole (14) of 2 mm diameter. This hole (14) is open at the proximal end of the base (11), and its distal end is closed inside the stem (12). The hole (14) has a length of 16 cm (length inside the stem (12)), so that the distance to the distal end (13) of the trocar (1) is approximately 2 cm.

[0035] Thus, during the introduction of the sheath (200)-trocar (1) assembly, the rounded distal end (13) of the trocar (1) protrudes from the end of the sheath (200), thus providing the assembly with an anatomically shaped distal end that facilitates introduction. In addition, by introducing an EM stylet (400) along the hole (14) it is possible to view the position of the trocar (1) in real time through the electromagnetic navigation system.

Claims

CLAIMS 1. Trocar (1) for electromagnetic navigation with a ventriculoscope, comprising a base (11) from which a rod (12) protrudes, where the base (11) has the shape of a body of revolution configured to fit into the rear end of the tube (210) of a sheath (200) of a ventriculoscope (100), and where the rod (12) has a cylindrical shape with a rounded distal end (13) for its introduction through the tube (210) of the sheath (200) of a ventriculoscope, characterized in that it also comprises a blind longitudinal hole (14) open at the proximal end of the base (11), said blind longitudinal hole (14) being configured to receive a stylet (400) of an electromagnetic navigation system.

2. Trocar (1) according to claim 1, wherein the blind longitudinal hole (14) has a diameter between 1.8 mm and 2.2 mm.

3. Trocar (1) according to claim 2, wherein the blind longitudinal hole (14) has a diameter of 2.0 mm.

4. Trocar (1) according to any of the preceding claims, wherein the blind longitudinal hole (14) has a length between 150 mm and 170 mm.

5. Trocar (1) according to claim 4, wherein the blind longitudinal hole (14) has a length of 160 mm.

6. Trocar (1) according to any of the preceding claims, which is manufactured by 3D printing.

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