EP3451957A1

EP3451957A1 - System for directed intraosseous injection of surgical cement

Info

Publication number: EP3451957A1
Application number: EP17726664.0A
Authority: EP
Inventors: François CORNELIS
Original assignee: Centre Hospitalier Universitaire de Bordeaux
Current assignee: Centre Hospitalier Universitaire de Bordeaux
Priority date: 2016-05-06
Filing date: 2017-05-04
Publication date: 2019-03-13
Also published as: US20190083267A1; FR3050925B1; WO2017191419A1; US11197761B2; FR3050925A1

Abstract

The invention concerns a system (10) for the intraosseous injection of surgical cement comprising an outer sleeve (11); a cannula (13) mounted coaxially in the outer sleeve, said cannula being capable of being moved along a longitudinal axis (A) in the outer sleeve, the cannula being provided with a tapered distal tip (15); and a stent (18) housed inside the outer sleeve, said stent being mounted about a distal end (16) of the cannula. The invention also concerns a kit comprising such a system for injecting surgical cement, means for injecting surgical cement suitable for being connected to the proximal end of the inner cannula, and, optionally, surgical cement.

Description

Intraosseous injection system for surgical cement

The invention relates to a system for injecting surgical cement intra-osseous, especially at low pressure. The system according to the invention is particularly suitable for the consolidation of a weakened bone, in particular a vertebral body or a pathological lachrymal lesion (malignant or benign) whatever the location.

For several decades, percutaneous injection of cement, such as cementoplasty, has developed to repair bone trauma (vertebral compression) or to fill lytic bone lesions (osteolytic metastases). This injection of cement, especially polymeric cement, must allow bone filling with mechanical properties substantially equivalent to those of the damaged bone. Advantageously, this bone consolidation is generally accompanied by a rapid decrease in bone pain in the patient.

Initially, the systems developed made it possible to directly inject cement into the area to be treated (under radiological control). Thus, cementoplasty is performed by percutaneous injection of cement through a needle, or trocar, introduced directly into the affected vertebral body or bone. Cementoplasty is particularly used in the treatment of osteoporotic fractures or, in some tumors, for the reinforcement of the affected vertebrae. However, the risks of leakage of cement to the outside of the bone body are high because of the absence of stress during the injection. However, because of the vascularization, the cement can quickly be found in the patient's venous system, with high risks of migration to the epidural and / or prevertebral veins, which can lead to pulmonary embolism.

Alternative systems have also been developed. Thus, kyphoplasty, or kyphoplasty, is very widely used in patients with more than one vertebral fracture, a collapse of the vertebra. This technique is particularly suitable for the treatment of bone fractures with vertebral crush, especially in young adults after trauma, since it allows the patient to recover a larger vertebral height. Kyphoplasty involves introducing a balloon through the trocar into the fractured vertebral body. Once in place, the balloon is inflated to gradually recover the vertebral height. The pressure used is then high. The balloon is then removed and cement is injected in its place, without resistance. However, after deflation and removal of the balloon, and before injection of the cement, there is frequently a partial loss of height, and therefore an insufficient correction resulting in persistent spinal pain.

In recent years, spinal fracture reduction systems using vertebral stents have been implemented. The stent is most often introduced simultaneously to the balloon and maintains the opening of the vertebral body between the balloon removal step and the cement injection. The applied pressure remains high. This technology, known in particular as "stentoplasty" or VBS for "Vertebral Body Stenting" has the further advantage of containing the majority of the cement in the volume of the stent, thus limiting the risk of leakage. Current systems used for stentoplasty, however, are complex in design and use. They require multiple and successive manipulations of trocars, means of swelling and balloon removal, means of cement injection, etc., making the intervention difficult. In addition, these systems are particularly dedicated to the treatment of traumatic vertebral fractures and can not be easily transposed to the treatment of other bone lesions, caused in particular by metastatic bone cancers. The pressure used is unacceptable, the risk of associated tumor migration being too high. In addition, the osteolytic nature of the lesions does not allow the deployment of this material in a healthy zone.

Thus, there is currently no satisfactory device for injecting low-pressure cement intra-bone simply and reliably, regardless of the position and nature of the bone to be treated.

The object of the invention is to at least partially solve the problem stated above, by proposing a single device that allows not only the placement of a stent in a bone body, but also the injection, advantageously directed, after the placing said stent in the bone body, bone cement in the volume of said stent. The system according to the invention does not require the use of an extrinsic mechanism for expanding the stent, and advantageously allows the establishment of a stent / cement assembly having synergistic biomechanical properties. The device according to the invention comprises in particular means for inserting a stent, able to bring the stent to the fracture or bone lesion to be treated and to allow its deployment once in position. More specifically, a system of concentric tubes that can be movable relative to each other successively enables the stent to be held in a constrained state, to bring it to the zone to be treated, and then to release it in order to that it deploys simultaneously or before injecting cement into the internal volume of said stent. Thus, the means for placing the stent according to the invention are also used for the injection of the cement, which makes it possible to limit the number of manipulations and simplifies the surgical procedure as a whole, allowing a quick and simple realization. To facilitate penetration into the bone body, the system further has a sharp end facilitating perforation and progression in the bone.

The invention therefore relates to a system for injecting intraosseous surgical cement comprising: - an outer sleeve;

an inner cannula mounted coaxially in the outer sleeve, said cannula being able to be displaced along a longitudinal axis in the outer sleeve, the cannula being provided with a tapered distal tip; and

a stent housed inside the outer sleeve, said stent being mounted around a distal portion of the cannula.

In the context of the invention, the term "distal" refers to a portion of an element that is furthest from the preemption zone of said element, as opposed to the "proximal" portion. In general, the distal portion of a system member refers to a portion of said member for penetrating the body of a patient as opposed to the proximal portion. According to the invention, the outer sleeve and the cannula advantageously have a generally cylindrical hollow or tubular shape. The sleeve and the cannula are coaxial, or concentric. The outer diameter of the cannula is strictly less than the internal diameter of the sleeve, so that said cannula, mounted in said sleeve, can move axially in the sleeve. According to the invention, the distal end of the cannula has a tapered tip, intended to facilitate the insertion of the system into the bone body. Advantageously, said tip opens at the distal end of the outer sleeve. The tip thus forms the distal end of the system, which comes first into contact with the body of the patient in which the stent is to be housed, so as to pierce the various parts of said body, to the target bone body. The distal tip of the cannula can thus protrude from the distal end of the sleeve, or simply flush with the mouth of the distal end of the sleeve.

In a particular embodiment, the distal end of the sleeve has a beveled tip, intended to facilitate insertion of the system into the body of the patient. In another embodiment, the distal end of the sleeve has a cross section.

In one embodiment, the proximal end of the cannula, opposite the distal end, is provided with coupling means adapted to be connected to surgical cement injection means. The coupling means may for example consist of a thread formed on the proximal end of the cannula, said thread, external or internal, then being complementary to a thread formed on the injection means. The coupling means may also consist of interlocking means, clips, etc.

In a particular embodiment, the coupling means allow a sealed coupling with the cement injection means.

In a particular embodiment, the cannula comprises a lateral orifice, able to let out surgical cement out of the cannula when it is injected into the internal volume of said cannula. Advantageously, the lateral orifice is formed in a distal portion of said cannula, intended to be inserted into the bone body to be treated, so that the cement can be released into said bone body.

According to the invention, in a configuration before use, the stent is mounted in a constrained state in the internal volume of the distal portion of the sleeve. A distal portion of the cannula is in contact with the stent so that the outlet of the distal portion of the cannula out of the sleeve also forces the stent out of said sleeve. For example, the stent is mounted around the outer wall of the distal portion of the cannula. So, the stent is kept in the internal volume of the sleeve, between the inner wall of said sleeve and the outer wall of the cannula.

Advantageously, the stent is a self-expanding stent. In a particular embodiment, the stent is wrapped around the distal portion of the cannula, so as to be constrained between the outer wall of the cannula and the inner wall of the sleeve. By moving the cannula in a direction distal to the sleeve, and / or by moving the sleeve in a direction proximal to the cannula, the stent is released, and no longer constrained by the wall of the sleeve, it deploys in the bone body around the distal part of the cannula. It is then possible to remove the cannula from the bone without moving the stent. In one embodiment of the invention, the system is provided with reversible blocking means capable of preventing any involuntary displacement of the cannula with respect to the sleeve, or vice versa. The locking means are used to maintain the position of the tapered tip of the cannula relative to the sleeve during the insertion of the system to the target bone body. The locking means can then be unlocked to allow movement of the sleeve and / or the cannula relative to each other. The locking means may for example consist of complementary threads on the cannula and the sleeve. For example, an inner wall of the proximal portion of the sleeve comprises a complementary thread of a thread formed on the outer wall of the proximal portion of the cannula. It is then not possible to accidentally change the position of the cannula in the sleeve. A rotation of one relative to the other is necessary to allow any displacement.

In another example, the locking means may consist of one or more retractable lugs on the outer wall of the cannula and housed in a first configuration in one or more complementary orifices in the wall of the sleeve. To allow the displacement of the cannula in the sleeve, it is then necessary to retract the lug or pins, for example by exerting pressure.

According to the invention, the system for injecting cement may be provided with control means making it possible to ensure the total release of the stent. For example, a marking is provided on the cannula, indicating to the user the maximum and / or minimum displacement distance of the sleeve in a proximal direction and / or the cannula in a distal direction, to ensure release of the stent. In a particular embodiment, the blocking means also serve as a means of control to ensure axial displacement of the cannula in the sufficient sleeve and / or limit this displacement. For example, the thread pitch of the threads on the cannula and the sleeve is calculated to allow movement of one relative to the other over a distance sufficient to ensure complete release of the stent from the inner volume of the sleeve. In the case of retractable lugs, it is possible to provide a second series of orifices on the sleeve, upstream of the first series. The displacement of the cannula in the sleeve is thus limited to the distance between the two series of orifices. In the context of the invention, the terms "upstream" and "downstream" refer to the direction of penetration of the system into a target bone body, the upstream designating the nearest part of said target bone body. Of course, a simple visual marking, for example at the proximal portions of the cannula and / or the sleeve can be used as control means.

Advantageously, the stent is a self-expanding stent made of shape memory material, so that once released from the outer sleeve, the stent deploys to at least partially recover the desired initial shape. Injection of the cement can also participate in the complete deployment of the stent in the bone. For example, the shape memory stent is made of nikel / titanium (Nitinol), cobalt-chromium or platinum-chromium alloy. In another embodiment, the stent is based on polymers, such as polylactic acid (PLA).

In a particular embodiment, the stent is covered with an outer casing intended to prevent or limit cement leaks. Advantageously, such an outer envelope is of stretchable material, or elastic, at least partially sealed. Advantageously, the outer envelope matches an outer contour of the stent. In a particular embodiment, the outer casing is made of polytetrafluoroethylene (PTFE).

The general form of the system according to the invention can advantageously be adapted to the morphology of the bone body to be treated. Thus, in one embodiment, the distal portion of the system, and more particularly the distal portion of the outer sleeve and the cannula has a straight profile. By profile is meant the external contour of the element under consideration. In another embodiment, the distal portion of the outer sleeve and the cannula has a curved profile, the curvature of the sleeve and the cannula being identical. This latter configuration is particularly suitable for the treatment of bones of the pelvis or ribs. In a particular embodiment, the outer sleeve has an external diameter of between 0.2 and 0.5 cm (ie between about 7 and 15 gauges), preferably between 0.3 and 0.4 cm, and a length between 10 and 15 cm. The cannula can then have a diameter of between 0.1 and 0.4 cm (ie between about 6 and 18 gauges), and preferably between 0.2 and 0.35 cm. In general, the dimensions of the outer sleeve and the cannula are adapted to the body of the patient to be treated, to the position of the target bone body in said body and to the nature of the bone lesion to be treated.

The stent may have dimensions (and in particular length and diameter) that vary depending on the nature and extent of the bone lesion to be treated. The stent does not generally fill the entire lesion, but must at least make it possible to form a pillar in said lesion to distribute the stresses between the regions of the bone body around the lesion. For example, the stent has a diameter of between 0.8 and 1.6 cm, for a length (or greater dimension) of between 4 and 6 cm.

The subject of the invention is also an intraosseous surgical cement injection kit comprising, in addition to the system for the cement injection described above, means for injecting the cement capable of being connected to the cement. proximal end of the cannula, and possibly surgical cement. For example, the injection means consist of a syringe whose injection end is coupled to the proximal end of the cannula. The end for injection, optionally provided with a needle, can thus be inserted into the proximal portion of the cannula. The insertion of the piston into the body of the syringe, previously filled with surgical cement, makes it possible to inject the cement into the cannula.

According to the invention, any surgical cement adapted for intraosseous use can be used. By way of non-limiting example, mention may be made of PMMA (polymethacrylate) type cements, commonly used in vertebroplasty. The kit may comprise the elements of the injection system already mounted, that is to say the cannula and the stent housed in the outer sleeve, or on the contrary said elements ready to be mounted.

In one embodiment, the injection means comprise pushing means for penetrating the cement into the interior of the cannula and forcing it to the stent. For example, the injection means comprise a piston intended to be inserted into the cannula, from the proximal end and adapted to slide axially in said cannula, towards the distal end.

The system according to the invention, wherein the stent is mounted around the distal portion of the cannula, can be used in a method of injecting surgical cement into a target bone body of a patient comprising the steps of:

Introduce the distal end of the cannula into the patient's body;

Continue insertion of the cannula and outer sleeve into the target bone body;

At least partially slide the outer sleeve out of the bone body to release the stent;

Begin injecting surgical cement into the internal volume of the stent using the cannula;

Sliding the cannula gradually out of the stent and the bone body while continuing the injection of surgical cement, so as to progressively fill the internal volume of the stent from the distal end to the proximal end of said stent;

Remove the outer sleeve and cannula from the patient's body.

Of course, it is possible to begin the injection of cement simultaneously with removal of the cannula. In general, once the stent ejected from the outer sleeve, the cannula can be used to inject the cement into the internal volume of said stent.

The invention also relates to a method of treating a bone body, such as a vertebra, comprising the steps above. The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These are presented as an indication and in no way limitative of the invention. The figures represent: FIG. 1: a partial schematic representation in longitudinal section of the system for injecting intraosseous surgical cement according to one embodiment of the invention, before use; Figure 2: a schematic representation of the system for injection of intraosseous surgical cement of Figure 1, in use;

Figure 3 is a schematic representation in longitudinal section of the distal end of the system for intraosseous surgical cement injection according to one embodiment of the invention;

FIGS. 4A and 4B: two examples of stents that can be used in the system for injecting bone cement according to the invention;

5A-5G: schematic representations of the system for the injection of intraosseous surgical cement according to one embodiment of the invention, at different stages of a stentoplasty method;

In Figure 1 is shown a partial view of a cement injection system 10 according to one embodiment of the invention. More specifically, the system 10 comprises an outer sleeve 11 of generally cylindrical shape with a right circular section. A distal end 12 of the sleeve 11 has a cross section. The outer sleeve 11 is hollow, and a cannula 13 extends along a longitudinal axis A in an internal volume 14 of said outer sleeve 11. The cannula 13, also hollow, has a generally cylindrical shape with a straight circular section, concentric with the outer sleeve 11. The internal diameter d of the cannula 13 is strictly smaller than the internal diameter D of the outer sleeve 11, so that a displacement along the axis A of the cannula 13 relative to the outer sleeve 11, or vice versa, is possible without friction.

The cannula 13 has a tapered distal tip 15. In the example shown in Figures 1 and 2, the distal tip 15 of the cannula 13 opens projecting from the distal end 12 of the outer sleeve 11. Thus, when the system 10 must pass through a target bone body is the tapered distal tip of the cannula 13 which first contacts the body, facilitating penetration. In another exemplary embodiment, as shown in FIG. 3, the distal end 12 of the sleeve 11, of constant diameter, is beveled, and the distal tip 15 of the cannula 13 is flush with the mouth of the distal end. 12. In this case, it is the beveled end of the sleeve 11 and the distal tip 15 of the cannula 13 which simultaneously engage the bone body, the beveled shape of the sleeve 11 also aiding penetration.

On a distal portion 16 of the cannula 13, an orifice 17 is provided. The orifice 17 must be of sufficient size to allow cement to flow through the cannula 13. A stent 18 is wound around the distal portion 16 of the cannula 13. The stent 18 is positioned on the cannula 13, so as to be fully housed in the internal volume 14 of the outer sleeve 11, and maintained in the space between the cannula and the sleeve. The stent is advantageously a self-expanding stent with shape memory. The stent 18 is maintained in a constrained, i.e., undeployed state, in the inner volume 14 of the sleeve 11. Figures 4A and 4B show two examples of stent 18 that can be used in the system

10 for intraosseous cement injection according to the invention. Advantageously, the mesh of the stent 18 is such that leakage of cements out of said stent are limited. According to a particular embodiment, as shown in Figure 4B, the stent 18 is completely covered with a film 19. The film 19 further reduces the risk of leakage of cement. For example, the film 19 is made of elastic waterproof material, for example PTFE.

Locking means (not shown) advantageously make it possible to reversibly hold the cannula 13 in this first position, or penetration position, in the outer sleeve 11. For example, the proximal ends of the outer sleeve 11 and the cannula 13 are provided with complementary threads, preventing any sliding of the cannula 13 in the outer sleeve 11. The displacement of the cannula 13 relative to the outer sleeve 11, and vice versa, is then possible only by rotating the relative to the other, in the direction to allow by the step of screws.

Figure 2 shows the system 10 in use. Specifically, the outer sleeve

11 was moved back towards the proximal end of the cannula 13, opposite to the distal end 15. This longitudinal displacement of a distance L makes it possible to release the distal portion 16 of the cannula and the stent 18. The stent 18 is being more constrained between the inner walls of the outer sleeve 11 and the cannula 13, it can be deployed to return to its original shape.

The cannula 13 and / or the sleeve 11 may be provided with visual cues (not shown) making it possible to inform the user of the sufficient or insufficient displacement of the sleeve with respect to the cannula, and therefore the complete release of the stent 18. The visual means are advantageously located at the proximal portions of the cannula 13 and / or the sleeve 11 so as to be outside the body of the patient during the use of the system 10.

Advantageously, in this second position, the orifice 17 of the cannula 13 is entirely in the internal volume of the stent 18. If necessary, it is conceivable to move the cannula 13 along the axis A, so as to position the orifice 17 at the desired location relative to the stent 18, and allow during the cement injection a homogeneous distribution of the cement throughout the volume of the stent 18.

An intraosseous surgical cement injection method will now be described using FIGS. 5A-5G. Such a method is advantageously implemented during the treatment of a patient, in particular a human patient, who has a bone trauma. For example, such a method can be implemented to achieve stentoplasty at an injured vertebra.

As can be seen in FIG. 5A, the system 10 for the surgical cement injection according to the invention is brought into the body 100 of a patient by the tapered distal end of the cannula 13, which first pierces and crosses the body 100 of the patient. The cannula 13 / outer sleeve assembly 11 is pressed into the body 100 of the patient to the target bone body 101 (FIG. 5B).

The outer sleeve 11 is then removed at least partially from the body 100 of the patient. Only the cannula 13, on which the stent 18 is mounted, remains in position in the bone body 101 (Figure 5C). The stent 18 can then be deployed in the bone body 101 (FIG. 5D).

Cement injection means (not shown), coupled to the proximal end 19 of the cannula 13 allow cement to be injected through the cannula 13 into stent 18 (Figure 5E). For example, a syringe filled with surgical cement is inserted into the cannula 13, by its proximal end. The piston of the syringe is pressed into said syringe to penetrate the cement into the cannula. The cement flows out of the cannula 13 through the lateral orifice (not visible) and fills the internal volume of the stent 18. During the injection phase of the cement, the cannula 13 is gradually removed from the bone body 101 (FIG. 5F ), the outer sleeve 11 can be held in position. It is also possible to start gradually removing the cannula / sleeve assembly. When the entire internal volume of the stent 18 is filled with cement, the cannula 13 and the outer sleeve 11 are entirely removed from the body 100 of the patient, leaving only the stent 18 containing the cement in position in the bone body 101.

Claims

System (10) for injecting intraosseous surgical cement comprising

an outer sleeve (11);

- A cannula (13) mounted coaxially in the outer sleeve, said cannula being adapted to be displaced along a longitudinal axis (A) in the outer sleeve, the cannula being provided with a tapered distal tip (15); and

a stent (18) housed inside the outer sleeve, said stent being mounted around a distal portion (16) of the cannula.

The intraosseous surgical cement injection system of claim 1, wherein the tapered distal tip of the cannula opens out of the outer sleeve.

The intraosseous surgical cement injection system of claim 1 or 2, wherein the outer sleeve is provided with a beveled distal tip (12).

4. A system for intraosseous surgical cement injection according to one of the preceding claims, wherein a proximal end of the cannula is provided with means for coupling to surgical cement injection means, so as to be able to inject cement through said cannula.

5. System for intraosseous surgical cement injection according to one of the preceding claims, wherein the cannula is provided with a lateral orifice (17) able to allow cement to pass from the inside to the outside. of said cannula.

6. System for injecting intraosseous surgical cement according to one of the preceding claims, wherein the stent is self-expanding.

7. A system for injecting intraosseous surgical cement according to claim 6, wherein the stent is of shape memory material, preferably of nickel / titanium alloy.

8. System for intraosseous surgical cement injection according to one of the preceding claims, wherein the stent is surrounded by an anti-leak film (19), preferably made of polytetrafluoroethylene (PTFE).

9. System for injecting intraosseous surgical cement according to one of claims 1-8, wherein the outer sleeve and the cannula have a straight profile.

10. A system for intraosseous surgical cement injection according to one of claims 1-8, wherein at least the distal end of the outer sleeve and the cannula have a curved profile.

11. Intraosseous surgical cement injection kit comprising a system for injecting intraosseous surgical cement according to one of claims 1-10, surgical cement injection means adapted to be connected to the proximal end of the inner cannula, and possibly surgical cement.