DEVICE FOR INJECTING BONE CAVITIES WITH FLUID CEMENT, PARTICULARLY FOR VERTEBROPLASTY OR THE LIKE

The present invention refers to a device for injecting bone cavities with fluid cement, particularly for vertebroplasty or the like. As is common knowledge, diseases such as osteoporosis, vascular necrosis and bone cancer are pathological disorders that weaken bones making them prone to fractures and/or collapse.

Such diseases are particularly dangerous, not to mention painful, for the person affected by them, especially if the backbone is involved and more specifically the vertebral bodies of the vertebrae that have to support the weight of the person's trunk.

As a rule, to treat painful vertebral fractures, but also fractures in other parts of the body like the distal and proximal ends of the femur and/or humerus, mini- invasive therapeutic procedures are usually opted for using bone cement to fix and strengthen the weakened bones.

These therapeutic procedures consist of injecting a polymethyl methacrylate, or the like, bone cement with a specially shaped metal needle into the vertebral body under the combined guidance of diagnostic systems such as CAT and digital fluoroscopy. The cement spreads inside the fractured vertebral body, preventing further progression.

It lessens pain and those patients who were forced to reduce their physical activity find they have acquired more mobility.

These therapeutic procedures however do have some drawbacks. Injecting cement into the cavity, in the vertebral body, compresses and squashes the bone marrow inside it, progressively increasing pressure on the marrow and cement injected.

This procedure is difficult for the operator and often painful for the patient.

It is also necessary to point out that if too much cement is injected at very high pressures it is likely the bone or marrow walls collapse and cement leaks from the bone cavity contaminating other parts of the organism, causing very serious damage which, in some cases, can be irreparable.

And even more problems can arise if there are carcinogenic cells where the fluid is injected since leaking cement could cause the tumour to spread outside the vertebrae.

Normally this operation is very slow and worrying to do and only highly qualified medical personnel can do it.

As an alternative to this treatment there is a therapeutic procedure where an inflatable element is inserted inside the cavity of the vertebral body beforehand.

By filling this inflatable element with a radiopaque or similar liquid, the bone marrow is pressed against the inner surface of the bone cavity, creating a hollow inside the vertebral body.

The inflatable element is subsequently emptied and removed from the vertebra and the hollow created inside it earlier is filled with bone cement using a syringe or the like.

Basically, this procedure allows the bone cement to be injected safely without any risk of it leaking since the bone marrow is not compressed by the cement but by the inflatable element.

Nevertheless, note that inflating the element is an additional task that adds to the time taken for the treatment.

Moreover, this procedure too features the same drawbacks mentioned above, basically difficult to do, painful for the patient, the danger of spreading cancer cells outside the vertebrae not to mention the fact that highly qualified medical personnel are required to do the job.

The main aim of this invention is to create a device and a procedure for injecting bone cavities with fluid cement, particularly for vertebroplasty or the like, that will overcome the difficulties of the known technique with a simple, rational and cost-effective solution.

Yet another purpose of this invention is to therapeutically treat said diseases quickly, easily and practically for the operator and under conditions of maximum safety and minimal discomfort for the patient. To this objective, another purpose of this invention is to stabilise diseased bones and prevent tumour cells, if any, from spreading.

These purposes are all attained with this device for injecting bone cavities with

fluid cement, particularly for vertebroplasty or the like, comprising at least one needle for injecting the cement fluid into a bone cavity which contains biological fluids, said needle featuring at least one filling-up opening to fill up said needle with said cement fluid outside said bone cavity and at least one injection opening to inject said cement fluid into said bone cavity, characterised by the fact that it comprises at least one channel for extracting said biological fluids from said bone cavity during injection of said cement fluid in said bone cavity, said channel featuring at least one inlet opening to let said biological fluids in from said bone cavity and at least one outlet opening to let said biological fluids out from said bone cavity, said injection opening and said inlet opening being able to be substantially positioned near each other inside said bone cavity.

These purposes are all attained also with this procedure for injecting bone cavities with fluid cement, particularly for vertebroplasty or the like, characterised in that it comprises the following steps:

- inserting in a bone cavity at least one channel for extracting the biological fluids contained in it;

- inserting in said bone cavity at least one needle for injecting a cement fluid; - injecting said cement fluid into said bone cavity through said needle inserted and simultaneously extract said biological fluids from said bone cavity through said channel inserted.

Further characteristics and advantages of this invention will appear even more evident from the detailed description of a preferred, but not exclusive, form of embodiment of a device for injecting bone cavities with fluid cement, particularly for vertebroplasty or the like, illustrated by way of non limiting example in the accompanying drawings, wherein: figure 1 is a side view of the elements composing the device according to the invention; figure 2 is a partial and schematic view of the device according to the invention during insertion of the extraction channel and of the closing element inside the vertebral body;

figure 3 is a partial and schematic view of the device of figure 2 after the closing element has been removed from the extraction channel; figure 4 is a partial and schematic view of the device of figure 3 after the needle has been inserted in the extraction channel for injecting the cement fluid and extracting the biological fluids contained in the vertebral body; figure 5 is a schematic view, partially in section and on an enlarged scale, of a detail of figure 4.

With special reference to the above figures, a device for injecting bone cavities with fluid cement, particularly for vertebroplasty or the like, has been generally designated by reference number 1.

The device 1 includes a needle 2 to inject a cement fluid F inside a bone cavity C containing biological fluids M.

In detail, the cement fluid F is a bone cement, for example a polymethyl methacrylate resin, eventually radiopaque, or other similar substance. In the particular form of embodiment of the invention illustrated in the figures, the bone cavity C is the hollow defined inside the cylindrical body of a vertebra V and the biological fluids M are those (blood, bone marrow, etc.) it normally contains. The possibility is, however, not excluded that this invention can be used to inject cement fluid F in bone cavities C of different shapes or of a different nature.

Usefully, the needle 2 has a filling-up opening 3 of the cement fluid, through which the cement fluid enters the needle 2 outside the bone cavity C, and an injection opening 4 of the cement fluid F which can be positioned inside the bone cavity C.

In detail, the needle 2 includes a first open end portion 5a where its edge defines the injection opening 4; said first end portion is shaped like the end of a flute simplifying penetration into the biological fluids M of the vertebra V. Opposite the first end portion 5a, the needle 2 features a second end portion 5b, also open, that defines the filling-up opening 3; this opening 3 features connecting means 6 to a tank 7 containing the cement fluid F. For example, the tank 7 consists of the body of an injection syringe whose

injecting end can be coupled with the connecting means 6 of the needle 2 which, advantageously, are of the threaded type.

Alternative forms of embodiment cannot, however, be excluded where the filling-up opening 3 of the needle 2 can be connected to a different device for injecting the cement fluid like, for instance, a gun, bellows or the like.

The device 1 according to the invention also includes a channel 8 for extracting the biological fluids M from the cavity C of the vertebra V while the cement fluid F is being injected into the cavity.

In detail, the channel 8 features an inlet opening 9 of the biological fluids M, through which the biological fluids M contained in the bone cavity C can enter the channel 8, and an outlet opening 10 for taking the biological fluids M outside the bone cavity C.

The injection opening 4 of the needle 2 and inlet opening 9 of the channel 8 can be positioned near each other inside the bone cavity C. The needle 2 and the channel 8 can be, in fact, associated lengthways and substantially coaxial one inside the other.

In the particular form of embodiment illustrated in the figures, the transversal dimensions of needle 2 are smaller than the transversal dimensions of channel 8 and can be inserted in the channel 8 after it has been placed in the vertebra V. In this way, when the needle 2 is inserted in the channel 8, a gap 11 is defined between the inside of the channel 8 and the outside of the needle 2 through which the biological fluids M exit from the cavity C of vertebra V.

Other ways of implementing this invention are, however, possible like, for instance, the transversal dimensions of the channel 8 can be smaller than the needle 2; in this case the channel 8 can be inserted in the needle 2 to define a gap between the inside of the needle 2 and the outside of the channel 8 through which the cement fluid F can be injected into the bone cavity C.

In detail, the channel 8 includes a first rigid and longitudinal tubular section 12 with a first open end 13a and a second open end 13b, opposite the first. The first open end 13a defines the inlet opening 9 shaped like the end of a flute which facilitates insertion of the channel 8 inside the vertebra V.

The needle 2 is substantially longer than the first tubular section 12 and can be

inserted inside it through the second open end 13b up to a working position where the first end portion 5a projects slightly from the first open end 13a. In addition, the channel 8 includes a second rigid tubular section 14 orthogonally associated to the first tubular section 12 and placed in fluid communication with it; the free end of the second tubular section 14 is open and defines the outlet opening 10 for the biological fluids M coming from the bone cavity C.

Advantageously, the device 1 also includes a closing element 15 of the inlet opening 9 of the channel 8 which substantially means the channel 8 can be put inside the bone cavity C without the channel filling up with the human tissues of the patient that are passed through during the insertion. In particular, the closing element 15 consists of a bar that can be inserted precisely inside the first tubular section 12 of the channel 8 and is substantially the same length as the first tubular section. The bar 15 features a first tip portion 16a, shaped like the end of a flute which can be positioned coplanar and flush with the edge of the first open end 13 a. On the opposite side of the first tip portion 16a, the bar 15 defines a second tip portion 16b fitted with fastening means 17 to the first tubular section 12 where the second open end 13b is; said fastening means are preferably of the threaded type.

It has in fact been found that the described invention achieves the intended purposes.

The invention thus conceived is susceptible of numerous modifications and variations, all of which falling within the scope of the inventive concept. Furthermore all the details can be replaced with others that are technically equivalent.

In practice, the materials used, as well as the shapes and dimensions, may be any according to requirements without because of this moving outside the protection scope of the following claims.