The present invention relates to a thoracic prosthesis and a method for realizing a thoracic prosthesis.

The term prosthesis means an artificial device adapted to replace a missing body part (for example a limb, an organ or a tissue), or to complement a damaged one.

In general, prostheses can be made to measure (for example dental or orthopaedic prostheses) or mass produced (for example heart valves).

Thoracic prostheses constitute a particular type of prosthesis adapted to replace a portion of a person’s ribcage which has been damaged, for example due to one of the many tumour pathologies that can affect the chest wall.

One of the most common methods for manufacturing the above- mentioned thoracic prostheses is the “Rib-like technique”, which uses an aluminium cast to produce ribcage portions, for example several ribs and the sternum.

The cast is a shaped support that reproduces, as an internal negative impression, the shape of an average ribcage.

In a first step, the internal cast is covered with a mesh, after which an acrylic material is modelled by hand over the mesh to form the portions of the ribcage it is intended to reproduce. The acrylic material is applied externally on the mesh without incorporating it therein.

Disadvantageously, this technique can only be used for ribcage replacement portions of a small size, for example the sternum and the front part of the ribs.

However, one often encounters a situation in which a more extensive part of the ribcage (in cases where the resection of the chest wall is considered larger: resection with a diameter greater than 10 cm), such as, for example, an entire hemisphere, is affected by a tumour and needs to be replaced. Moreover, working by hand does not ensure sufficient reproducibility and reliability.

In order to overcome such drawbacks, prostheses made of PMMA have been developed; they are produced thanks to the use of a mould having the shape of a whole thorax or of two hemithoraces.

Such prostheses guarantee high compatibility with the human body and have a sufficient flexo-torsional rigidity such as to protect the internal organs.

Disadvantageously, in the frequent cases in which the replacement of only a portion of the thorax is required, the prostheses must be finished after moulding and adapted to the specific opening left in the patient’s body, resulting in a considerable increase in the time required and a large waste of material.

These two solutions cannot be made to measure, as the moulds are the same for all prostheses.

Another type of solution is titanium prostheses that are made to measure (i.e. modelled on the basis of the results of biomedical imaging tests on the specific patient) with additive technologies (typically Selective Laser Melting or Electron Beam Melting).

Disadvantageously, the rigidity of such prostheses, intrinsically tied to the use of titanium, may lead to the occurrence of problems during their connection to the person’s body.

In other words, such prostheses can prove to be difficult to adapt to the patient’s ribcage when, for example, it becomes necessary to increase the area of intervention intraoperatively due to problems not detected or not detectable by means of biomedical imaging systems.

Furthermore, the rigidity and weight of such devices makes them uncomfortable and they are often an obstacle to taking a complete breath. Disadvantageously, moreover, the high costs of procuring and processing titanium are reflected in the final price of the prosthesis, placing a large burden on the patient’s and/or the health system’s finances. In this context, the technical task at the basis of the present invention is to propose a thoracic prosthesis and a method for realizing a thoracic prosthesis which overcome the above-mentioned drawbacks of the prior art.

In particular, it is an object of the present invention to provide a thoracic prosthesis that increases comfort for the patient undergoing the implantation.

A further object of the present invention is to provide a thoracic prosthesis and a method for realizing a thoracic prosthesis that enable the operations of implantation in the patient to be simplified.

Another further object of the present invention is to provide a thoracic prosthesis that enables an easy modification of the dimensions thereof by healthcare personnel, using the instruments already currently available in surgery, by cutting and shaping the prosthesis itself during the surgical intervention so that it can be easily adaptable to the conformation of the body of different patients.

A further object of the present invention is to provide a thoracic prosthesis and a method for realizing a thoracic prosthesis which enable the production costs to be reduced compared to prior art devices.

The stated technical task and specified objects are substantially achieved by a thoracic prosthesis and a method for realizing a thoracic prosthesis comprising the technical features disclosed in one or more of the appended claims.

The dependent claims correspond to possible embodiments of the invention.

Additional features and advantages of the present invention will emerge more clearly from the approximate, and thus non-limiting, description of a thoracic prosthesis and a method for realizing a thoracic prosthesis as illustrated in the appended figures, in which:

- figure 1 is a perspective view of a thoracic prosthesis in accordance with a possible embodiment of the present invention; - figure 2 is a perspective view of a thoracic prosthesis in accordance with a further possible embodiment of the present invention.

With reference to the appended figures, the numerical reference 1 denotes in its entirety a thoracic prosthesis, which hereinafter will be indicated as the prosthesis 1 .

The prosthesis 1 comprises a plurality of costal elements 2 spaced from one another and defining respective intercostal spaces 3 therebetween.

In accordance with a possible embodiment and as illustrated in the appended figures, each costal element 2 has a respective main direction of extension “X”.

Advantageously, the costal elements 2 have a substantially two- dimensional conformation.

In other words, the costal elements 2 can have a substantially ribbon-like form.

In this manner, the costal elements 2 generate a minimal bulk inside the patient’s body, thus facilitating lung expansion.

Furthermore, this conformation contributes to increasing the flexibility of the prosthesis 1 , thus ensuring high adaptability to the breathing process. The costal elements 2 preferably have a thickness comprised between 1 and 10 millimetres, even more preferably they have an average thickness of about 15 millimetres; it should be noted that the thickness can vary with the length of the costal elements 2.

According to further embodiments, not illustrated in the appended figures, the costal elements 2 can have a different conformation, for example an oval, elliptical or circular cross section, without the inventive concept at the basis of the present invention being altered.

Advantageously, at least one of the costal elements 2 can have one or more openings 4 adapted to increase the flexibility of the thoracic prosthesis and/or enable a connection with a portion of a patient’s body.

In accordance with some possible embodiments and as illustrated in the appended figures, each costal element 2 has one or more openings 4, thus ensuring a high flexibility of the thoracic prosthesis.

The prosthesis 1 further comprises at least one connection portion 5 disposed in the intercostal spaces 3.

Advantageously, the connection portion 5 has a grid-like or perforated structure that ensures a very light weight and flexibility of the prosthesis 1 . Furthermore, it allows an exchange of fluids between the inside and outside of the ribcage, so as to reduce the risk of seromas or haematomas developing in the postoperative period and thus determining an increase in the risk of infections of the prosthesis itself.

In accordance with a possible embodiment and as illustrated in the appended figures, the prosthesis 1 comprises two connection portions 5 disposed in the intercostal spaces 3 defined by three costal elements 2 and respectively connected to two consecutive costal elements 2.

The connection portion 5 is connected to the costal elements 2 so as to contain and/or promote a development of biological material.

In other words, the connection portion 5, besides contributing to the protection and containment of organs, permits the insertion of thoracic muscles that were not resected during the operation so as to enable optimal respiratory mechanics even after implantation of the prosthesis. The connection portion 5 preferably has a plurality of passages 6 defining a substantially a grid-like conformation.

In particular, the above-mentioned passages 6 have a maximum size comprised between 3 and 5 millimetres, preferably about 5 mm.

In accordance with some possible embodiments and as illustrated in the appended figures, the connection portion 5 can have a grid-like conformation with polygonal meshes, for example substantially quadrangular (figure 1 ) and/or triangular (figure 2) meshes.

According to further embodiments not illustrated in the appended figures, the above-mentioned meshes can have a different conformation, for example circular and/or elliptical, without the inventive concept at the basis of the present invention being altered. The passages 6 and/or the above-mentioned openings 4 can preferably receive, by insertion, connection means, for example screws and/or wires of various kinds, adapted to connect the prosthesis 1 to respective portions of the patient’s thorax.

Advantageously, the costal elements 2 and the connection portions 5 are produced entirely in one piece.

In this manner, the prosthesis 1 will not have junction points that could give rise to cracks and subsequent fractures, which can cause it to break. Furthermore, producing it in one piece enables the production process to be simplified and sped up, overcoming the need for a step of connecting together the costal elements 2 and the connection portions 5.

Advantageously, the prosthesis 1 can be made of plastic material, which reduces production costs compared to the costly prostheses made of titanium, while maintaining mechanical characteristics comparable to those of the human ribcage.

In this manner, the prosthesis 1 can be easily trimmed or cut, for example by means of special scissors or clippers, also during the intervention by doctors and/or healthcare professionals, so as to adapt it to the structure of the patient’s ribcage.

Preferably, the above-mentioned plastic material is or comprises polypropylene and/or polymethylmethacrylate and/or polyether ether ketone and/or PETG and/or other biocompatible plastic materials.

In accordance with a possible embodiment and as illustrated in the appended figures, the prosthesis 1 can comprise at least one support portion 7 connected to a respective end of the costal elements 2.

In particular, the support portion 7 can define at least partially the patient’s sternum.

In particular, the support portion 7 can extend transversely, preferably perpendicularly, to the costal elements 2.

The support portion 7 can preferably be produced in one piece with the costal elements 2 and the connection portions 5. Furthermore, the support portion 7 can have one or more openings 4 adapted to increase the flexibility of the thoracic prosthesis and/or enable a connection with a portion of a patient’s body.

Advantageously, the prosthesis 1 can have a conformation obtained by means of a biomedical imaging process, thus ensuring high precision and dimensional accuracy (measurement on the basis of a computerised axial tomography scan of the patient for the curvature values and the arc of the ribs).

Furthermore, the prosthesis 1 can be produced by means of a 3D printing process, thus overcoming the need for costly moulds and ensuring high operating flexibility during the production process.

In particular, the integration of biomedical imaging with 3D printing guarantees the possibility of producing prostheses that are customised for the specific thoracic conformations of individual patients at limited costs.

In particular, 3D printing ensures the possibility of producing prostheses having any conformation whatsoever, for example an entire hemithorax, or comprising only some costal elements or even only some portions thereof, imparting high flexibility to the production process.

The prosthesis 1 is preferably printed with larger dimensions than the actual dimensions of the portion of thorax that must be removed from the patient and is subsequently adapted to the specific conformation of the patient’s thorax by operating room personnel by means of special scissors or clippers.

In accordance with a further aspect, the present invention makes reference to a method for realizing a thoracic prosthesis comprising a step of realizing a three-dimensional digital model of at least one portion of a thorax.

The method preferably comprises a step of morphological reconstruction of at least one portion of a patient’s ribcage by means of biomedical imaging in order to realize a three-dimensional digital model.

Furthermore, the method comprises a step of realizing a complete thoracic prosthesis by means of a single 3D printing process on the basis of the three-dimensional digital model.

The 3D printing can preferably take place in accordance with one or more of the Selective Laser Sintering and/or Fused deposition modelling and/or Stereolithography technologies.

The 3D printing step preferably comprises producing the thoracic prosthesis with larger dimensions than the actual dimensions of the portion of thorax that must be removed from the patient, so that it can be subsequently adapted to the specific conformation of the patient’s thorax by operating room personnel by means of special scissors or clippers.

It should thus be observed that the present invention achieves the proposed objects by providing a thoracic prosthesis and a method for realizing a thoracic prosthesis which are capable of increasing comfort for the patient undergoing implantation thanks to the presence of a plurality of costal elements and at least one connection portion disposed in the intercostal spaces produced entirely in one piece of plastic material so as to facilitate the breathing process thanks to the high flexibility.

Advantageously, the production from plastic material enables an easy adaptation to the specific thoracic conformation of the patient during implantation by the doctor or by the operating room team.

Advantageously, moreover, the present invention enables the production costs to be reduced compared to prior art devices by overcoming the need for costly moulds and the use of titanium.