WO2006051401A2

WO2006051401A2 - Medical device for the guided regeneration and modelling of bone and method for producing said device

Info

Publication number: WO2006051401A2
Application number: PCT/IB2005/003379
Authority: WO
Inventors: Sergio Moro
Original assignee: Oralplant Srl
Priority date: 2004-11-12
Filing date: 2005-11-11
Publication date: 2006-05-18
Also published as: ITUD20040213A1; WO2006051401A3

Abstract

Medical device for the guided regeneration of bone, able to be disposed between a bone surface (12) and a corresponding soft tissue (14), in order to define, between the bone surface (12) and the soft tissue (14), an interspace (13) in which the bone regeneration is able to be produced. The interspace (13) is able to be achieved by means of an element (11) comprising at least an attachment zone (15), able to allow it to be attached to the bone surface (12), and at least a separation zone (16) able to separate the flow of blood in the soft tissue (14) from the flow of blood in the bone surface (12).

Description

"MEDICAL DEVICE FOR THE GUIDED REGENERATION AND MODELLING

OF BONE AND METHOD FOR PRODUCING SAID DEVICE"

* * * * *

FIELD OF THE INVENTION The present invention concerns a medical device able to be used for the regeneration and modeling of bone, by detaching soft tissues from bone tissues, forming between them an interspace sufficient to obtain a so-called "tent effect". The present invention also concerns the method for producing said medical device which in medical terminology is also known as a grid with membrane. To be more exact, the device according to the invention can be used in various medical-surgical specializations, such as for example dentistry, odonto-stomatology, orthopedics, implantation of surgical osteo-integrated prostheses, conditioned and personalized anatomical prostheses, and also in the field of maxillo-facial surgery and osteosynthesis.

BACKGROUND OF THE INVENTION In the medical-surgical field it is known that in order to effect a guided regeneration or modeling of the bone, medical devices are normally used which generally consist of an osteosynthesis grid, normally made of metal, to which a membrane is associated on the upper part, the membrane consisting of animal collagen, synthetic material or other. The function of the grid is to support the soft tissues disposed around the bone, so as to define an interspace between them and the bone, thus obtaining a so-called "tent effect". With the grid the membrane creates a skeleton for the structure and is able to totally or partly block the flow of blood in the soft tissues with respect to the flow of blood in the bone, encouraging bone regeneration. Known grids have a standardized flat shape, and are provided with holes with a fixed diameter, which therefore require, at the moment of use, to be cut and modeled according to the bone anatomy desired. Moreover, known grids have holes with a relatively large diameter, for example in the order of about 1.20±0.2 mm, in order to allow them to be attached to the bone by means of osteosynthesis screws, so as not to cause infections and exposure. The holes are widened according to the diameter of the pitch of the osteosynthesis screw, with the aid of tungsten millers or other tools with a high number of revolutions.

Membranes of a known type, such as have been used until now, can be indifferently of the re-absorbable or non re- absorbable type, even if they are not always perfectly tolerated by the patient's organism.

The positioning of the known medical device with respect to the bone portion to be regenerated therefore provides the modeling and attachment to the bone of both the metal grid and also of the membrane, so as to obtain the "tent effect".

When the time necessary for the regeneration of the bone has passed, the grid and non re-absorbable membrane are both removed. Moreover, when osteo-integrated prostheses are used, it is known to use the members which attach the prosthesis in order to attach the grid directly to the bone, creating the attachment hole with the aid of tungsten millers or other tools with a high number of revolutions. In this case, on the contrary, in order to attach the membranes it is indispensable to make the attachment holes at the moment of use, with the aid of sharp surgical scissors, bending the membrane in the desired holing point and cutting a right angle necessary for the passage of the attachment members of the osteo-integrated prosthesis. This operation must be performed to attach the osteosynthsis screws too. The preparation steps described above must be added to the modeling of the grids and the membranes.

However, all this can cause imprecisions and substantial waste of time during an operation with an open incision, with the consequent increase in the risk of contamination for the patient.

Another disadvantage of the state of the art is that with devices as used until now it is difficult to keep the membrane perfectly positioned with respect to the grid, which is a disadvantage for the quality of the bone regeneration performed.

Moreover, the known solution creates a relatively great thickness, for example about 1.3 mm, due to the overlapping of the grid and membrane, which makes it difficult to suture the soft tissues, and can lead to possible lacerations of the latter during the patient's normal activities, with a consequent failure of the operation and possible infection of the parts affected.

The American patent US-B-6,409,764 discloses medical methods and objects for the regeneration of bone or periodontal tissue in which, in order to obtain the so- called "tent effect", the presence of a membrane or cage is provided, made of soft and flexible material, necessarily located below the protective element made of hard material. The European patent EP-A-O 622 052 discloses a method for producing a membrane to control the regeneration of the bone, in which the presence of metal spacer inserts is always provided between the bone part treated and the lower part of the membrane, in order to keep the membrane distanced from the bone part and obtain the so-called "tent effect".

One purpose of the present invention is to achieve a medical device for the guided regeneration of bone which has a reduced thickness with respect to known devices, so as to limit to a minimum the disadvantages connected to the positioning of the grid and the membrane, the suture and possible laceration of the soft tissues.

Another purpose of the present invention is to achieve a medical device for the regeneration of bone wherein the positioning and attachment to the bone is simple and rapid to effect.

Another purpose of the present invention is to perfect a method for producing said medical device, which allows to personalize the latter to the real requirements of the individual patient and the real bone part on which it has to be applied.

The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the main claim, while the dependent claims describe other characteristics of the invention or variants to the main inventive idea.

In accordance with the above purposes, a medical device for the guided regeneration of bone according to the present invention is able to be disposed between a bone surface and a corresponding soft tissue, to define between them an interspace in which the bone regeneration takes place. Said interspace is achieved by means of a single element which supports the soft tissue with respect to the bone surface. Advantageously, the single element has at least an attachment zone which allows it to be attached to the bone surface, and at least a separation zone which separates the flow of blood in the soft tissue from the flow of blood in the bone surface, so as to promote the bone regeneration. Said attachment zone comprises a plurality of attachment seatings each of which is suitable to accommodate a corresponding attachment member, such as for example an osteosynthesis screw or suchlike. Moreover, each of said attachment seatings comprises a substantially circular central hole, from which at least a hollow branches off radially, preferably two or more, able to cooperate with the thread of said attachment member so as to prevent the accidental dis-association of the latter from said element.

In this way a single element is used, structured for the guided regeneration of the bone, the function of which is to support the soft tissues, creating an interspace between the soft tissues and the bone areas, which function is normally performed by the grid, and also to create a barrier with a "tent effect", until now defined by the membrane.

The single element is advantageously made of a flexible material and has a reduced thickness with respect to the state of the art; said thickness for example varies from about 0.1 mm to about 0.4 mm.

In this way the thickness of the entire medical device is reduced, thus eliminating the problem of the correct positioning of the membrane and the disadvantages due to the difficulty of suturing the soft tissues, and the possible lacerations of the latter during the patient's normal activities.

Moreover, the fact that there is a single shaped element allows to reduce the number of instruments and tools needed, and consequently, the costs and times of the intervention.

In accordance with another inventive feature of the present invention, the medical device can be made using a method which uses real anatomical modeling on the patient for whom the device is made, starting from the results of an X-ray, CAT scan (Computed Axial Tomography), or similar detection techniques, and by means of a CAM program (computer aided manufacturing), instead of hand-modeling on the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other characteristics of the present invention will become apparent from the following description of a preferential form of embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 shows a plane view of the medical device for the regeneration of bone according to the present invention; - figs. 2a-2c show in sequence three steps of a first type of positioning of the medical device in fig. 1;

- figs. 3a-3c show in sequence three steps of a second type of positioning of the medical device in fig. 1;

- fig. 4 is an example of a CAT; - figs. 5 to 8 show some examples of application of one or more medical devices according to the present invention.

DETAILED DESCRIPTION OF A PREFERENTIAL FORM OF EMBODIMENT With reference to the attached drawings, a medical device 10 according to the present invention is used for the regeneration and modeling of bone in various medical- surgical specializations such as dentistry, odonto- stomatology, orthopedics, implantation of prostheses or other.

To be more exact, the medical device 10 according to the invention comprises a single element 11, made of flexible material, such as for example titanium, stainless steel, nontoxic plastic materials or other, and has a very limited thickness, for example comprised between 0.1 mm and 0.4 mm, so that it can easily be bent and attached to a bone surface 12 to be regenerated, in order to define an interspace 13 between the bone surface 12 and the soft tissues 14 normally disposed around the bone surface 12.

In this case, the element 11 is substantially flat and without bends, so that it can be modeled and bent directly by the surgeon at the moment of positioning.

According to some constructional variants, in order to reduce the time required for the bone regeneration, the element 11 can have a pre-determined anatomical shape depending on the specific bone or bone regions on which it is applied, or it can be pre-shaped in a personalized manner on the patient, according to previous X-rays, CAT scans or other techniques that detect the shape and disposition of the bone.

According to another variant, the element 11 is made curved so that, at rest, it already assumes the necessary shape to be associated with the bone or the bone region on which it has to be positioned.

According to a characteristic of the invention, the element 11 comprises two attachment zones 15, disposed peripherally, and a substantially central separation zone 16. Each of the attachment zones 15 comprises a plurality of attachment seatings 17, each one having a central hole 17a, substantially circular and from which one or more hollows 17b branch off radially. In the example shown here, there are two hollows 17b, disposed on diametrically opposite sides with respect to the central hole 17a.

In said attachment seatings 17 are housed corresponding osteosynthesis screws 19, by means of which the element 11 is attached to the bone surface 12, defining the interspace 13.

Advantageously, the inner diameter of each central hole 17a is comprised between 0.5 mm and 1.5 mm, and is equal to the diameter of the core of the osteosynthesis screws 19. The radial distance of each hollow is about 0.1-0.5 mm, and is equal to the thickness of the thread of the osteosynthesis screws 19 (difference between the outer radius and radius of the core).

The shape of the attachment seatings 17 allows to keep the osteosynthesis screws 19 associated with the element 11 even when it is separated from the bone, without the risk that the osteosynthesis screws 19 can be accidentally dis¬ associated from it. The association of the osteosynthesis screws 19 with the element 11 is maintained thanks to the coupling of the pitches of the threads of the screws 19 and the corresponding hollows 17b of the attachment seatings 17.

This characteristic is particularly advantageous in the field of dental surgery where the accidental fall of an osteosynthesis screw 19 into the patient's mouth can also entail the risk of serious accidents for the patient.

Moreover, the reduced area of the hollows 17b greatly limits the overall section of the holes 17, which remain free, that is, in use, they are not affected by the osteosynthesis screws 19.

The separation zone 16 comprises a plurality of micro- holes 20, with a diameter for example in the order of tenths of a millimeter, which allow to separate the flow of blood in the bone from the flow of blood in the soft tissues 14, promoting the bone regeneration inside the interspace 13.

The disposition of the micro-holes 20 in the separation zone 16 also allows the element 11 to be stronger and more resistant to external physical compressions, thanks to the greater availability of resistant structure.

Moreover, as shown by the line of dashes in fig. 1, the element 11 can comprise an attachment hole 21 which, as will be explained in detail hereafter, allows the medical device 10 to be positioned also in the presence of an osteo-integrated prosthesis 22.

As shown in figs, from 2a to 2c, a first type of positioning of the medical device 10 according to the invention provides a first step wherein the soft tissue 14 is cut at a point to define two lips 14a and 14b which are then scraped from the bone surface 12 to be regenerated and modeled.

The medical device 10 is then interposed between the two lips 14a, 14b of soft tissue 14 and the bone surface 12, attached to one or more sides of the latter by means of the osteosynthesis screws 19, shaped to define the desired interspace 13, and finally attached to the other side of the bone surface 12, again by means of the osteosynthesis screws 19, to define its definitive installation.

When this operation is terminated, the two lips 14a and 14b of soft tissue 14 are replaced above the element 11 and sutured together in a zone 18.

According to the variant shown in figs, from 3a to 3c, the medical device 10 according to the invention can also be positioned in the presence of an osteo-integrated prosthesis 22. In this case, apart from the above steps referring to the previous case, another clamping of the element 11 is made, to the osteo-integrated prosthesis 22 present, by anchoring an upper part of the latter to the element 11, using an attachment screw 23 inserted in the attachment hole 21. A method according to the present invention for producing a medical device 10 of the type described above comprises the following steps:

- a first step in which, from the radiologist's work station, the volumetric data are acquired, with good tomographical images, perpendicular or in directions made known, thus creating the axis of the bone area affected, developing with said axis known reference and measurement points, suitable for reading mathematical data of the tomographical images produced (fig. 4); - a second step of processing the mathematical data supplied by the radiologist, by means of a known program for calculators, dedicated to post-processing data, in order to develop tomographical images suitable for anatomical and radiological study, intended for the display, in virtual manner, for the reconstruction of the bone model available, making known in three-dimensional fashion the bone sizes to be corrected with the positioning of the medical device 10. The program for the calculator must allow to display in 3D (three construction axes of the solid model) the tomographical geometrical-mathematical data, supplied by the radiologist and concerning the bone part involved, allowing the graphical interaction thereof, the complete surgical-prosthetic planning and the identification of anatomic structures, of interest for the intervention, that could not otherwise be displayed;

- a third step wherein the volumetric and axial data acquired are subjected to post-processing which is able to give a preliminary evaluation on the three-dimensional planes of the clinical case. By viewing the examination on axes and graphical reference points chosen by the operator in three-dimensional evaluations, it is possible to correct "Personalized Bone Forms", for the subsequent creation in producing the medical device 10, making it anatomical and personalized with the bulges chosen by the surgeon suitable for the expansion of the desired bone regeneration (figs. 5 to 8);

- a fourth step of receiving, directly or telematically, said geometric-mathematical data, graphical points processed or to be processed, by the company that will make the medical device 10;

- a fifth step of producing the medical device 10, using equipment and machine tools connected to CAD-CAM acquisition systems (three-dimensional solid working), able to create and model the anatomical and personalized medical device 10, so that the surgeon finds all the shapes he needs for the most simple application in the patient.

With the method thus described it is possible to define, in a personalized and extremely anatomical manner, the shape of the medical device 10, which otherwise it would not be possible to achieve integrally with anatomic adaptations for its personalized modeling profile, with appropriate bulges necessary to create the "tent effect" with the same device. This "Personalized Modeling" can in no way be achieved directly by the surgeon during his intervention on the patient.

Each medical device 10 thus made, including possible bulges provided in the third step, can also be partly overlapping over another medical device 10, creating, if necessary, a concatenation of devices, so as to cover greater non-rectilinear areas (figs. 5 and 7).

It is clear that modifications and/or additions of parts may be made to the medical device 10 and the relative method to produce it as described heretofore, without departing from the field and scope of the present invention. It is also clear that, although the invention has been described with reference to specific examples, a person of skill in the art shall be able to achieve other equivalent forms of medical device for the guided regeneration and modeling of bone, having the characteristics as set forth in the claims and therefore all coming within the field of protection defined thereby.

Claims

1. Medical device for the guided regeneration of bone, able to be disposed between a bone surface (12) and a corresponding soft tissue (14), in order to define, between said bone surface (12) and said soft tissue (14), an interspace (13) in which said bone regeneration is able to be produced, characterized in that said interspace (13) is able to be achieved by means of an element (11) comprising at least an attachment zone (15) able to allow said element (11) to be attached to said bone surface (12), and at least a separation zone (16) able to separate the flow of blood in said soft tissue (14) from the flow of blood in said bone surface (12), in that said attachment zone (15) comprises a plurality of attachment seatings (17) each able to accommodate a corresponding attachment member (19) , and in that each of said attachment seatings (17) comprises a substantially circular central hole (17a), from which at least a hollow (17b) branches off radially, able to cooperate with a thread of said attachment member (19) in order to prevent the accidental dis-association of said attachment member (19) from said element (11).

2. Medical device as in claim 1, characterized in that each of said attachment seatings (17) comprises two or more of said hollows (17b), disposed radially with respect to said central hole (17a).

3. Medical device as in claim 1, characterized in that each of said attachment seatings (17) comprises two of said hollows (17b), disposed diametrically and on opposite sides with respect to said central hole (17a).

4. Medical device as in any claim hereinbefore, characterized in that said separation zone (16) comprises a plurality of micro-holes (20), able to allow the separation of the flow of blood in the bone from the flow of blood in said soft tissue (14), promoting said bone regeneration inside said interspace (13).

5. Medical device as in any claim hereinbefore, characterized in that said element (11) also comprises one or more attachment holes (21) of a size such as to allow one or more osteo-integrated prostheses to be associated with said element (11), by means of another attachment member (23).

6. Medical device as in any claim hereinbefore, characterized in that said element (11) is made of flexible material and has a limited thickness so as to be easily bent and modeled, eliminating the difficulties of suturing the soft tissues and the possible laceration thereof.

7. Medical device as in any claim hereinbefore, characterized in that said element (11) has a pre¬ determined anatomical shape depending on the bone or bone regions on which it is able to be positioned.

8. Medical device as in any claim hereinbefore, characterized in that said element (11) is pre-shaped in a personalized manner on the patient on whom it is to be positioned, according to previous X-rays, CAT scans or other detecting techniques to detect the shape and disposition of the specific bone or bone regions on which said element (11) is able to be positioned.

9. Medical device as in any claim hereinbefore, characterized in that said element (11) is made curved so as to assume at rest the necessary shape to be associated with the specific bone or bone regions on which it is able to be positioned.

10. Medical device as in any claim hereinbefore, characterized in that it is shaped so as to be able to be at least party overlapping above another adjacent medical device, in order to cover greater bone areas, even not rectilinear.

11. Medical device as in any claim hereinbefore, characterized in that it includes at least a bulge in the zone able to develop said bone regeneration.

12. Method for producing a medical device according to any one of the claims hereinbefore, characterized in that it uses the real anatomical modeling of the part of the patient who is to be operated on, starting from the results of an X-ray, a CAT scan, or similar detection techniques, and by means of a CAM program, instead of modeling by hand on the patient.