Implants for pelvis reconstruction are widely used in orthopedic oncology. Such implants are often used in cases of bone and soft tissue sarcomas located in or around the pelvis, and in cases of metastatic bone disease (M.B.D.).

The prior art discloses a variety of pelvic endoprostheses specifically adapted for replacement of a selected portion of a patient's pelvis, depending on the site of origin of the tumor and the location of metastases. Such pelvic endoprostheses may be adapted to replace selected portions of the ilium, sacrum, acetabulum ,ischium and pubis of the patient.

Most of the implants currently used for the replacement of pelvic parts between the acetabulum and the sacrum of a patient usually feature low bio-mechanical stability and integrity owing to their flat configuration.

Currently, such configuration is the most commonly used since it makes it possible to immediately transplant the implant without the need to specifically pre-design the implant to a specific patient.

The flat configuration of the currently used implants is mechanically unfavorable since it fails to provide firm and stable long-term connection to the pelvis and sacrum of a patient, mainly because such portions of the patient's body feature a complex three dimensional configuration. The load on the screws connecting such implants to the bone surfaces of the pelvis and sacrum is not distributed in an optimized manner, exposing the screws to harsh transverse forces which decrease the long-term bio-mechanical stability, integrity and durability of the implant.

Various attempts have been made to design pelvic implants of a three dimensional configuration specifically adapted for a specific patient (customized implants) so as to provide better bio-mechanical stability and integrity to the complex bone-implant. Most of these implants are tailor- made by using methods of precision casting.

Further, various attempts have been made to design three- dimensional pelvic endoprostheses for total hip replacement, wherein the proximal femur and the periacetabular area of the patient have to be reconstructed.

However, such implants can be made only after the precise boundaries of the malignant areas have been determined. The preparation of such implants usually takes between four to six weeks. Such a waiting period may be too long for a patient with a failing pelvis due to a metastatic bone disease. Moreover, since the dimensions and shape of such implants are not changeable, the implant may become unsuitable for implantation after that period of time owing to progress of the disease.

Furthermore, the production method of precision casting is complex and expensive.

There is thus a widely recognized need for, and it would be highly advantageous to have, a modular versatile implant for pelvis reconstruction which can be adapted to any specific patient during a real-time operation.

It would be further advantageous to have a versatile implant capable of adopting a desired three dimensional shape by changing the orientation of its surfaces. It would also be advantageous to have an implant whose shape can be determined and formed real-time in an operation so as to allow immediate transplantation. It would be further advantageous to have such an implant which has favorable mechanical features. It would be further advantageous to have an implant which allows a reliable, firm and stable long-term connection to the bone surfaces of a patient, and which is prepared by using simple and inexpensive production methods.

SUMMARY OF THE INVENTION According to the present invention there is provided an implant for replacement of a region of a pelvic bone, preferably between the acetabulum and the sacrum of a patient, including: (a) a main surface for connecting a first portion of the pelvic area and a second portion of the pelvic area; (b) at least one end surface connected to the main surface; and (c) at least one bending zone for changing the orientation of the at least one end surface relative to the main surface.

According to further features in preferred embodiments of the invention described below, the implant may further include: (a) at least one cantilever element connected to the at least one end surface; and (b) at least one bending zone for changing the orientation of the at least one cantilever element relative to the at least one end surface.

Each of the cantilever elements may include at least one bending zone for changing the orientation of a portion of the cantilever element.

Specifically, the implant may include a first cantilever element connected to a first end surface and a second cantilever element connected to a second end surface, the first cantilever element for connection to an acetabulum of a patient and the second cantilever element for connection to a sacrum of a patient.

According to still further features in the described preferred embodiments, the end surface may be bent along any line within the limits of the bending zone so as to form an angle of between about 0 and about 30 degrees with the main surface.

The cantilever element may be bent along any line within the limits of the bending zone so as to form an angle of between about 0 and about 30 degrees with the end surface.

Further, a portion of the cantilever element may be bent along any line within the limits of the bending zone so as to form an angle of

between about 0 and about 90 degrees, or alternatively, between about 0 and about 120 degrees with the rest of the cantilever element.

According to still further features in the described preferred embodiments, the implant includes a stiffening rib. The stiffening rib may feature a convexo-concave shape in cross section.

An implant according to the present invention further includes holes for connecting the implant to the bony surfaces of the pelvis of a patient, preferably by means of screws.

Further, an implant according to the present invention may include an extension extending substantially along the longitudinal side of the main surface, the extension being oriented so as to form a predetermined angle with the main surface, thereby forming a stiffening crest between the main surface and the extension.

Further, the extension may feature a longitudinal bend extending along its longitudinal axis, the bend defining a first portion and a second portion of the extension such that the second portion being oriented so as to form a predetermined angle with the first portion, thereby enabling to substantially enclose a portion of the patient's pelvis.

An implant according to the present invention may further include openings for receiving a thread therein so as to allow to suture patient's muscles to said implant.

Further according to the present invention there is provided a bending tool for bending a pelvic implant, comprising: (a) an accommodating member having a slot for receiving a surface of the implant therein; (b) a bending member having at least one bending extension for bending a portion of the surface, the accommodating member featuring a convex surface and the bending member featuring a concave surface so as to allow sliding of the bending member over the accommodating member.

Further according to the present invention there is provided an implant for replacement of a pelvic bone by connecting a first portion and a second portion of the pelvic bone, comprising: (a) a cup acetabular prosthesis; (b) a first main surface for connecting the first portion of the pelvic bone to the cup acetabulum prosthesis; (c) a second main surface for connecting the second portion of the pelvic bone to the cup acetabulum prosthesis, wherein each of said first and second main surfaces includes: (i) at least one end surface connected thereto; and (ii) at least one bending zone located between the main surface and the at least one end surface for changing the orientation of the at least one end surface relative to the main surface.

Further, the at least one end surface may include at least one circumferential protrusion, the at least one protrusion including a hole for receiving a screw therein, the at least one protrusion including a bending zone for individually bending the at least one protrusion relative to the at least one end surface.

Preferably, the first main surface is connected to the cup acetabulum prosthesis by means of a first adapter, and the second main surface is connected to the cup acetabulum prosthesis by means of a second adapter.

According to still further features of the invention described below, the cup acetabulum prosthesis includes a protrusion, and at least one of the adapters includes a depression for accommodating said protrusion therein, such that the protrusion is movable within the depression, thereby allowing to change the orientation of the cup acetabulum prosthesis relative to the at least one adapter. The implant may include a lock screw for fixing the position of the cup acetabulum prosthesis with relation to the at least one adapter. Further, the first adapter is preferably movable with relation to the first main surface.

Preferably, the first portion of the pelvic bone includes the patient's ilium. Alternatively, the first portion of the pelvic bone includes the patient's sacrum. Preferably, the second portion of the pelvic bone includes the patient's pubis.

Further according to the present invention there is provided a method for reconstructing a region of a pelvic bone, comprising: (a) resecting a portion of the pelvic bone; (b) manually shaping a substantially flexible template so as to so as to connect selected remaining portions of the pelvic bone; (c) substantially immediately shaping a pelvic implant according to the shape of said template by means of a bending tool; and (d) connecting said implant to the selected remaining portions of the pelvic bone.

The present invention successfully addresses the shortcomings of the presently known configurations by providing a modular versatile implant for pelvis reconstruction capable of adopting a desired three dimensional shape by changing the orientation of its surfaces. Thus, the shape of such an implant can be determined and formed during a real-time operation, thereby allowing immediate transplantation. Such an implant has favorable bio-mechanical features since it provides an optimized distribution of load on the screws connecting the implant to the bony surfaces of the pelvis, thereby not exposing such screws to harsh transverse forces which decrease the long term stability and durability of the implant.

The present invention discloses a novel modular implant for pelvis reconstruction. While using an implant according to the present invention, the exact size and three-dimensional shape of the implant required for a specific patient is determined during surgery by means of a template which is easy to bend and is identical in shape and size to the required implant.

The template is shaped by the surgeon so as to fit the exact dimensions of the pelvic area of a given patient after resection. The implant is then shaped according to the template by using a hand bending tool.

BRIEF DESCRIPTION OF THE DRAWINGS The invention is herein described, by way of example only, with reference to the accompanying drawings, wherein: FIG. 1 is a perspective view of an implant according to the present invention before adopting its three dimensional conformation; FIG. 2 is a partial cross sectional view across line A-A in FIG. 1; FIG. 3 is a perspective view of an implant according to the present invention while adopting its three dimensional conformation; FIG. 4 is a schematic view of an implant attached to a pelvic girdle of a patient; FIG. 5 is a cross sectional view across line B-B in FIG. 4; FIG. 6 is a top view of another embodiment of an implant according to the present invention; FIG. 7 is a cross sectional view across line A-A in FIG. 6; FIG. 8 is a top view of yet another embodiment of an implant according to the present invention; FIG. 9 is a cross sectional view across line D-D in FIG. 8.

FIG. 10 is a schematic view of a bending tool according to the present invention; FIG. 11 is a cross sectional view of across line A-A in FIG. 10; FIG. 12 illustrates the operation of a bending tool according to the present invention; FIG. 13a is a schematic view of another embodiment of a bending tool according to the present invention; FIG. 13b is a cross sectional view across line A-A in FIG. 13a; FIG. 14 is a cross sectional view of a pelvic endoprosthesis adapted for total-hip replacement; FIG. 15a is a top view of a selected surface of the endoprosthesis shown in FIG. 14, for connection to the patient's ilium;

FIG. 15b is a perspective view of another embodiment of the surface shown in FIG. 14a; FIG. 16 is a cross sectional view of another embodiment of a pelvic endoprosthesis adapted for total hip replacement; FIG. 17a is a view, partially in cross section, of yet another embodiment of a pelvic endoprosthesis adapted for total hip replacement; FIG. 17b is a cross sectional view of zone I in FIG. 17a; DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is of a modular implant for pelvis reconstruction which can be adapted to a specific patient during a real-time operation.

Specifically, according to the present invention there is provided an implant which may be used for the replacement of pelvic portions between the acetabulum and the sacrum of a treated patient. A versatile implant according to the present invention is capable of adopting a desired three dimensional shape from a given, preferably flat, configuration by changing the orientation of its surfaces. The shape of such implant can be determined and formed during a real-time operation so as to allow an immediate transplantation.

Further, according to the present invention there is provided an implant which may be used for total hip replacement, wherein reconstruction of the proximal femur and the periacetabular area is needed.

The principles and operation of an implant according to the present invention may be better understood with reference to the drawings and the accompanying description.

Referring now to the drawings, FIGs. 1-5 illustrate an implant according to the present invention preferably for replacement of pelvic portions between the acetabulum and the sacrum of a patient. As shown in FIG. 1, an implant according to the present invention preferably

includes: a main surface 1 having a stiffening -rib 2 disposed along the longitudinal axis of surface 1; two end surfaces 3 and 4 located at each end of surface 1; and two cantilevers 10 and 11 connected to end surfaces 3 and 4, respectively. Stiffening rib 2 is preferably of a convexo-concave shape in cross section, as shown in FIG. 2. Preferably, the longitudinal side 19 and the transverse sides 20 and 26 of main surface 1 feature a rounded shape so as to minimize damage to soft tissues. As shown in FIG.

1, cantilevers 10 and 11 are connected to end surfaces 3 and 4. A slot 5 defines the dimensions and shapes of cantilevers 10 and 11. Preferably, slot 5 includes a longitudinal portion 6 and a cutout portion 7, such that the edges 8 and 9 of cantilevers 10 and 11, respectively, form an angle of between about 60 degrees and about 90 degrees with the edge of longitudinal portion 6.

As shown in FIG. 3, an implant according to the present invention further includes bending zones, preferably zones 13, 14, 15, 16, 17 and 18. Preferably, each of end surfaces 3 and 4 and each of cantilevers 10 and 11 include a group of holes 12 for screws, such that bending zones 13, 14, 15, 16, 17 and 18 are formed between the groups of holes 12.

When using an implant according to the present invention, end surfaces 3 and 4 may be bent along any line within the limits of bending zones 13 and 18, respectively, so as to form an angle of preferably between about 0 and about 30 degrees with main surface 1.

Cantilever 10, preferably for attachment to the acetabulum of a patient, may be bent along any line within the limits of each of bending zones 14 and 15. Preferably, cantilever 10 is bent along a line within the limits of bending zone 14 to form an angle of between about 0 and about 30 degrees with end surface 3, and along a line within the limits of bending zone 15 to form an angle of between about 0 and about 120 degrees between the two parts of cantilever 10 spaced by bending zone 15.

Cantilever 11, preferably for attachment to the sacrum of a patient,

may be bent along any line within the limits of bending zones 16 and 17.

Preferably, cantilever 11 is bent along a line within the limits of bending zone 17 to form an angle of between about 0 and about 30 degrees with end surface 4, and along a line within the limits of bending zone 16 to form an angle of between about 0 and about 90 degrees between the two parts of cantilever 11 spaced by bending zone 16.

When bending the implant of the present invention into a three- dimensional shape as described above and attaching the implant to a patient's pelvic area, the load is distributed among screws 25 (FIG. 5) in an optimized manner. Since cantilevers 10 and 11 are bent with relation to main surface 1, screws 25 are not susceptible to harsh transverse forces.

Thus, the long-term bio-mechanical stability of the implant is improved.

The edge 21 of cantilever 10 preferably features a rounded shape so as to facilitate the attachment of end surface 3 and cantilever 10 to the acetabulum. The edges 8 and 9 of cantilevers 10 and 11, respectively, feature a rounded shape so as to minimize damage to soft tissues.

While using an implant according to the present invention, the exact size and three-dimensional shape of the implant required for a specific patient is determined during surgery by using a thin metal template which is easy to bend and is identical in shape and size to the required implant.

The template is shaped by the surgeon so as to fit the exact dimensions of the pelvis and sacrum of a given patient after resection. The implant is then shaped according to the template by using a hand bending tool (Figs.

10-13). When fitting the implant to a pelvic area (FIG. 4), cantilever 10 is preferably supported by, and attached to, bony surface 24 formed by the resection of the pelvis, while end surface 3 is supported by, and attached to, bony surface 22 in the immediate proximity of the acetabulum.

Cantilever 11 and end surface 4 are preferably supported by, and attached to, bony surface 23 of the sacrum.

The present invention is preferably provided as a set of modular units of templates and pertinent implants of different size, and a hand bending tool for bending the implants. For example, a set of modular units may include templates and pertinent implants having lengths of between about 80 mm and about 140 mm, and graded with differences of about 5- 10 mm. The templates and implants are preferably made of stainless steel commonly used for endoprostheses. The method of production used for preparing the implants preferably includes cold stamping and electro- polishing of the implant surface.

Referring now to Figs. 6 and 7, according to another embodiment the implant of the present invention does not include a stiffening rib, but rather includes an extension 30 for conferring a desired stiffness to the implant. As shown in the figures, extension 30 is preferably in the form of a flat surface connected to or integrally made with main surface 1 and extends along its longitudinal axis. Extension 30 is preferably oriented so as to form a predetermined angle with main surface 1, thereby defining a crest 33 for conferring a desired rigidity to the implant. Extension 30 preferably includes holes 12 for screws. Further, extension 30 preferably includes openings 32 for insertion of medical thread therethrough so as to allow a surgeon to secure the patient's pelvic muscles to the implant by means of stitches, thereby facilitating recovery of the pelvic area.

Referring now to Figs. 8 and 9, according to yet another embodiment extension 30 includes a first surface 30a and a second surface 30b, the second surface 30b being oriented so as to form a predetermined angle with first surface 30b, thereby defining a crest 30c therebetween.

Preferably, first surface 30a is oriented so as to form about 90 degrees with main surface 1. Since such configuration includes a plurality of crests - crest 33 and crest 30, it features an improved stiffness relative to the configuration shown in Figs. 6 and 7. Further, such configuration enables

to substantially enclose bony portions of the pelvis, thereby allowing to effectively secure the implant to the pelvis.

As shown in Fig. 8, openings 32 for suturing the patient's muscles to the implant are preferably included within main surface 1.

Referring now to Figs. 10-12, a hand bending tool 40 for shaping an implant of the present invention is shown. As specified above, the exact three dimensional shape of the implant required for a specific patient is determined during surgery by using a thin metal template which is easily bent and shaped by the surgeon. The implant is then immediately shaped according to the template by means of hand banding tool 40.

As shown in Fig. 10, bending tool 40 preferably includes: an accommodating member 46 including a slot 51 for receiving a selected surface of the implant; and a bending member 48 including a bending extension 53 for bending a portion of the selected surface relative to the rest of the implant while the selected surface is received within slot 51.

Preferably, accommodating member 46 features a convex edge 50 and bending member 48 features a concave edge 52, convex edge 50 being received within concave edge 52, so as to allow sliding of bending member 48 over accommodating member 46.

As shown in the figure, accommodating member 46 and bending member 48 include respective handles, 47 and 49, for holding bending tool 40 by a user. Preferably, handles 47 and 49 feature bends, 41 and 42 respectively, for facilitating bending of the implant.

As shown in Fig. 10, slot 51 preferably extends through a portion of the width of accommodating member 46.

As shown in Fig. 11, slot 51 preferably extends completely through the thickness of accommodating member 46. Accommodating member 46 and bending member 48 are preferably interconnected by means of a connecting element 54 having a "U" shape, which connecting element being secured to each of members 46 and 48 by means of screws 55.

Fig. 12 exemplify the operation of a bending tool 40 according to the present invention, wherein cantilever 10 is bent along bending zone 15 as concave bending member 48 slides over convex accommodating member 46.

Referring now to Fig. 13a, another embodiment of bending tool 40 is shown, wherein bending member 48 includes a pair of bending extensions, 53a and 53b, so as to facilitate the manipulation of the implant by means of bending tool 40. Further, as shown in Fig. 13a, slot 51 preferably extends completely through the width of accommodating member 46 so as to allow symmetrical operation of bending tool 40.

Thus, for example, cantilever 10 may be bent by means of extension 53a and cantilever 11 may be bent by means of extension 53b, thereby enabling symmetrical manipulation of the implant without the need to substantially change the orientation of the implant relative to bending tool 40.

As shown in Fig. 13b, accommodating member 46 is preferably thick in cross section and slot 51 extends through a portion of the thickness of accommodating member 46. Connecting member 54 for connecting member 46 and member 48 preferably features an "L" shape, and is secured to each of members 46 and 48 by means of screws 55.

According to the present invention there is further provided an endoprosthesis which may be used for total hip replacement, wherein reconstruction of the proximal femur and the periacetabular area is needed.

Referring to Fig. 14, a transverse section of a patient's body is shown, wherein a resection of the left pelvic portion has been performed, which resection including the proximal femur, the periacetabular area, the left portion of the pubis, and a portion of the ilium.

As shown in the figure, a pelvic endoprosthesis according to the present invention includes a cup acetabulum prosthesis 70 for receiving a conventional femur prosthesis therein. Prosthesis 70 is mechanically

connected to a first surface 74 by means of a first adapter 72, and to a second surface 75 by means of a second adapter 73, the first surface for attachment to the patient's ilium, and the second surface for attachment to the right portion of the patient's pubis.

As shown in the figure, cup acetabulum prosthesis 70 and first adapter 72 are interconnected by means of screws 77; first adapter 72 and first surface 74 are interconnected by means of screws 78; and first surface 74 is secured to the patient's ilium by means of screws (not shown in the figure) .

Further as shown in the figure, cup acetabulum prosthesis 70 and second adapter 73 are interconnected by means of screws 77; second adapter 73 and second surface 75 are interconnected by means of screws 76; and second surface 75 is secured to the left portion of the patient's pubis by means of screws 79.

Cup acetabulum prosthesis 70 may feature specific sizes. Further, adapters 72 and 73 may feature specific dimensions and shapes so as to allow adaptation of the prosthesis to different patients.

First and second surfaces 74 and 75 may be shaped by means of hand bending tool 40 so as to adopt a specific three dimensional shape, as required.

The exact three dimensional shapes of first and second surfaces 74 and 75 are determined during surgery by using a thin metal template which is easily bent and shaped by the surgeon. Surfaces 74 and 75 are then immediately shaped by means of hand banding tool 40.

Figs. 15a and 15b show possible configurations of first surface 74.

Surface 74 preferably includes two bending zones, 92a and 92b, extending along the longitudinal axis of surface 74, along which surface 74 is bent by bending tool 40. Such configuration allows to substantially enclose a bony portion of the patient's ilium so as to effectively fix surface 74 thereto. As shown in the figures, surface 74 preferably includes holes 12

for screws, the screws for securing surface 74 to the patient's ilium.

Preferably, surface 74 includes a plurality of circumferential protrusions 91 separated by depressions 90 such that each of holes 12 is located on a distinct protrusion. As shown in Fig. 15b, each of circumferential protrusions 91 may be independently bent along a specific protrusion bending zone 93, thereby enabling to specifically adapt surface 74 to a specific bone structure.

Surface 75 may feature a similar configuration as shown for surface 74.

Fig. 16 shows another embodiment of a pelvic endoprosthesis according to the present invention. As shown in the figure, the patient's ilium has been resected, and first surface 74 extends to reach the patient's sacrum and is preferably connected to the patient's sacrum by means of screws (not shown in the figure). When using such embodiment, surface 74 may include a cantilever element, substantially as shown in Fig. 4.

Referring to Figs. 17a and 17b, according to another embodiment the orientation of cup acetabulum prosthesis 70 is adjustable so as to prevent displacement of the femur prosthesis.

As shown in the figures, cup acetabulum prosthesis 70 preferably includes a hollow cylindrical extension 85 received within a hollow cylindrical chamber of adapter 72. Thus, cup acetabulum prosthesis 70 may be rotated along the longitudinal axis of cylindrical extension 85 (designated as A) by rotating cylindrical extension 85 within the hollow cylindrical chamber of adapter 72. Since cup acetabulum prosthesis 70 is unsymmetrical with reference to longitudinal axis A (best shown in FIG.

17a), such rotation results in changing the orientation of cup acetabulum prosthesis 70 relative to adapter 72. Lock screw 80 is used to fix cup acetabulum prosthesis 70 at a desired position.

As shown in the figure, adapter 72 is preferably connected to surface 74 by means of an excentric pin 82. Such connection allows to

slightly change the orientation of adapter 72 with reference to surface 74, substantially as designated by arrow B. Lock screw 84 is used to fix adapter 72 at a desired position.

While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made.