WO2005072631A1

WO2005072631A1 - Set of surgical equipment for the fixing of bone pieces

Info

Publication number: WO2005072631A1
Application number: PCT/HU2005/000004
Authority: WO
Inventors: József Farkas
Original assignee: Sanatmetal Kft.
Priority date: 2004-01-30
Filing date: 2005-01-26
Publication date: 2005-08-11
Also published as: HU0400305D0

Abstract

The equipment contains supporting elements (10, 30) that each have a shaft (11, 31) and a head (12, 32) and a connection (20) inserted between heads (12, 32) The heads (12, 32) have holes (15, 16, 35, 36) and slots (15a, 16a, 35a, 36a) extending out from the holes (15, 16, 35, 36) a cylindrical surface (13, 33) of the head (12, 32) and openings (15c, 16c, 35c, 36c) extending to the top surface (17, 37) of the head (12, 32). The connection (20) is formed by rods (21) that each have connection bodies (21a, 21c) at each end connected by a spine (21b); one connection body (21a) of the rod (21) is fitted into a hole (15, 16) of one head (12) while the other (21c) is fitted into a hole (35, 36) of the other head (32); and the spine (21b) of the rod (21) is guided through the slots (15a, 16a, 35a, 36a). The connection heads (12, 32) each have at least two accommodations holes (15, 16, 35, 36); the holes (15, 16, 35, 36) near the top surface (17, 37) of the connection head (12, 32) have independent connection pieces (15d, 16d, 35d, 36d) e.g. threads, and independent clamping bodies (41) e.g. screws are allocated to the connection pieces (15d, 16d, 35d, 36d).

Description

Set of surgical equipment for the fixing of bone pieces

The subject of the invention relates to a set of surgical equipment for the fixing of bone pieces, especially for maintaining the positions of vertebrae as compared to each other, which contains supporting elements that each have a threaded shaft that can be screwed into the bone to be fixed and a connection head connected to the threaded shaft, as well as a connection part-unit inserted between the connection heads of the supporting elements, the connection heads of the supporting elements are delimited by a cylindrical surface and a top surface, the connection heads have an accommodation zone suitable for connecting the connection part- unit and a clamping structure fixing the connection part-unit in the accommodation zone, in at least a part of the connection head of the supporting elements the accommodation zone has accommodation holes and slots extending out from the accommodation holes to the cylindrical surface of the connection head and opening parts extending to the top surface of the connection head, the connection part-unit is formed by a set of rod elements that each have a first connection body, a second connection body and a spine member connecting these two, the first connection body and the second connection body of the rod elements positioned between the two supporting elements are at least partially delimited by a space curve, in a practical case by a spherical shell part, furthermore, the one connection body of the rod element connecting two neighbouring supporting elements is fitted into the accommodation hole of the accommodation zone of the connection head belonging to the one supporting element, while the other connection body of the rod element is fitted into the accommodation hole of the accommodation zone of the connection head belonging to the other supporting element, the part of the spine member of the rod element in the proximity of the one connection body is guided through the slot of the accommodation hole of the one supporting element, and the part of the spine member of the rod element in the proximity of the other connection body is guided through the slot of the accommodation hole of the other supporting element, and it is in this way that two neighbouring supporting elements are connected to one another.

Today in the field of spinal surgery implants are used in numerous cases in order to maintain the positions of the vertebrae as compared to each other. The essence of these is that screw-like supporting elements are fixed into the vertebrae, which are connected to each other with the assistance of rod-like connection bodies, and in this way the supporting elements are joined to become a single load transfer structure. Solutions containing connection bodies consisting of such rigid, longitudinal rod elements can be found in patent specifications registration number US 5.603.714., registration number US 6.074.393., and registration number HU 209.422., while constructions using connection bodies consisting of several wires can be found in publication documents number FR 2.745.706. and GB 2.294.394.

The disadvantage of the known solutions that have rigid connection bodies is that the lengths of the usual supporting elements serving to connect them up, and the complex fixing structure resulting in significant dimensions makes the operation difficult, and so "hiding" the built in structural elements cannot be solved in every case.

Another disadvantage is that in the cases of traditional structures with rigid connection bodies during positioning and fixing the connection rods become deformed and stressed, which in an extreme case can lead to breakage of the components, further injury to the person being treated. A disadvantage deriving from this is that in the case that the components become broken the fixing of the vertebrae is terminated and therefore the desired state can only be restored via a further operation, so causing significant burden for the patient.

In order to eliminate such problems attempts have been made to use spinal screws with a so-called "adjustable head", which, however, cannot be used for connecting more than two vertebral bodies, because the rigid rods should be bent in space exactly to the shape required by the position of the spinal screws. At the same time, in the course of an operation it is impossible to solve rigid rods or plates with such great accuracy, following an individual space curve in each case, because of a lack of time and required target tools.

A further deficiency of the known versions is that the ordinary screwed joint fixation is liable to fatigue, and a further operation is required for the replacement of a failed element or the correction of the fixation.

It is also unfavourable that in the case of spinal implants affecting three or more vertebral bodies screwing the supporting elements into the vertebral body and connecting the connection bodies created from a long rigid rod at the right level in space causes great difficulties, requires a large number of special tools and appliances and significantly prolongs the operation time, which unnecessarily increases the burden on the patient and also the possibility of complications occurring in the course of the operation.

It must also be regarded as a disadvantage that in the case of traditional solutions on different sections of the vertebral column rods of different sizes need to be used and different fixations in accordance with it in a given case, which makes the quick and efficient realisation of the operation even more difficult.

In order to eliminate these deficiencies fixation devices have been constructed in the case of which in the connection head situated at the end of the threaded shaft fixed in the bone a recess is made opposite the cylindrical surface. Then, in this hole practically going through the connection head fixation rods are inserted, which can leave the connection head through the side openings, while inside the hole of the connection head they have an enlarged connection piece. On top of the connection head a fixing element is placed the task of which is to fix the enlarged connection piece into the connection head. Such surgical equipment is described in patent specifications No. US 5984.923. and EP 346.521 and from utility model specification No. DE 9402695.

However, the disadvantage of this solution is that the rod-ends in the connection head are all in the same hole, and they are fixed into the connection head with a fixing element. However, fixing several structural elements - that can be moved with respect to each other - at the same time and as one single unit makes the constructed surgical equipment unstable, and even in the case of small loading there is a danger of the rod elements becoming displaced, which may have undesired consequences for the person wearing such equipment.

Our aim with the invention was to eliminate the disadvantages of the solutions using the known connection head construction and connection part-unit containing rods and to create a set of surgical equipment for fixing together bone pieces and vertebral bodies, which has a simple structure, is easy to handle and is still highly rigid and facilitates more lasting bone and vertebrae fixation in a way that the connection heads of the supporting elements extending to different directions and different heights can be easily fastened together, and the area exposed during the operation and the time needed for the operation can be significantly reduced. The construction according to the invention is based on the recognition that if instead of the ordinary long, rigid straight rod the connection part-unit is assembled from shorter rod elements with specifically shaped ends, and in the connection heads accommodation holes completely different from the known ones are created to suit the ends of the rod elements, each one of which accommodation holes is for accommodating one single rod element, and a clamping body is attached to each accommodation hole, which clamping bodies can be separately handled, then a novel connection locking with force and form can be created, where the rod elements can be connected to the connection heads one by one with a significantly greater degree of freedom and to each other exclusively through the connection heads, and in this way, by securely fixing the supporting elements and the rod elements a fixed-angled structure freely shaped in space can be constructed, which is completely suitable for maintaining the position of the supporting elements with respect to each other to the desired extent, and so the task can be solved.

The idea behind the invention was also based on the recognition that if the specially constructed connection head is separated from the threaded shaft, and they are attached to each other so that they can be moved and turned with respect to each other, then the connection of the rod elements and the connection heads can be solved with an even greater degree of freedom, and it is also possible to create more than two accommodation cavities inside the individual connection heads, as a result of which nodes with several branches can be realised.

In accordance with the set aim the set of surgical equipment for the fixing of bone pieces, especially for maintaining the positions of vertebrae as compared to each other, - which contains supporting elements that each have a threaded shaft that can be screwed into the bone to be fixed and a connection head connected to the threaded shaft, as well as a connection part-unit inserted between the connection heads of the supporting elements, the connection heads of the supporting elements are delimited by a cylindrical surface and a top surface, the connection heads have an accommodation zone suitable for connecting the connection part- unit and a clamping structure fixing the connection part-unit in the accommodation zone, in at least a part of the connection head of the supporting elements the accommodation zone has accommodation holes and slots extending out from the accommodation holes to the cylindrical surface of the connection head and opening parts extending to the top surface of the connection head, the connection part-unit is formed by a set of rod elements that each have a first connection body, a second connection body and a spine member connecting these two, the first connection body and the second connection body of the rod elements positioned between the two supporting elements are at least partially delimited by a space curve, in a practical case by a spherical shell part, furthermore, the one connection body of the rod element connecting two neighbouring supporting elements is fitted into the accommodation hole of the accommodation zone of the connection head belonging to the one supporting element, while the other connection body of the rod element is fitted into the accommodation hole of the accommodation zone of the connection head belonging to the other supporting element, the part of the spine member of the rod element in the proximity of the one connection body is guided through the slot of the accommodation hole of the one supporting element, and the part of the spine member of the rod element in the proximity of the other connection body is guided through the slot of the accommodation hole of the other supporting element, and it is in this way that two neighbouring supporting elements are connected to one another, - is constructed in a way that in at least a part of the connection heads one of the accommodation holes of the accommodation zone is combined with one or more other accommodation holes independent from it, on the part of the delimiting wall between the first accommodation hole and the second accommodation hole near the top surface of the connection head there are first connection pieces independent from each other, and the clamping unit is formed by a group of independent clamping bodies that are allocated to the first connection pieces separately, can be connected to the first connection pieces in a displaceable way and are provided with a second connection piece co-operating with the first connection pieces.

A further criterion of the set of surgical equipment may be that in at least a part of the supporting elements the first accommodation hole and/or the second accommodation hole has a cylindrical delimiting wall.

In the case of a possible construction of the set of equipment in at least a part of the supporting elements, at the end of the first accommodation hole and/or the second accommodation hole opposite the opening part there is a recess extending into the supporting element.

In the case of another different construction of the invention the main axis of the first accommodation hole and the main axis of the second accommodation hole of the individual supporting elements are at a maximum angle of 10° with respect to each other, favourably they are parallel to each other. The first connection piece and the second connection piece are screw threads.

From the aspect of the set of equipment it may be favourable that the threaded shaft and the connection head of the supporting element are made in one piece.

In the case of a further construction of the invention the connection head of the supporting element is provided with an opening for guiding through at least a part of the threaded shaft, and a part of the threaded shaft is clamped in the opening. The connection head of the supporting element is provided with an aperture running between the opening and the cylindrical surface of the connection head. The connection head of the supporting element is combined with a fixing part-unit containing the first fixing body and the second fixing body, and the first fixing body of the fixing part-unit is situated on one side of the aperture, while the second fixing body of the fixing unit is situated on the other side of the aperture.

In the case of an even further construction of the invention the main axis of the first accommodation hole and the main axis of the second accommodation hole of the individual supporting elements and the main axis of the threaded shaft of the supporting element are at a maximum angle of 10° with respect to each other, favourably they are parallel to each other.

The most important advantage of the set of equipment according to the invention is that by using the accommodation holes of a novel construction and the connection heads containing the clamping bodies separately allocated to the accommodation holes and the rod elements, each one of which fits in the accommodation holes, the stable and lasting fixation of the position of the vertebral bodies can be solved in a simply and quick way even in cases when the connection heads of the supporting elements can only be fixed to the individual vertebral bodies with a significant difference in angle and height. An advantage deriving from this is that with the use of the novel set of equipment the time needed for the operation can be reduced as well as the physical burden on the operating surgeon and the patient.

A further advantage is that due to the connection part-unit, which is different from the known ones, the novel set of equipment can be used both on the dorsal and lumbar sections, as a result of which fewer parts and fewer and simpler tools need to be used for a successful intervention. This also improves the possibility of a quick intervention.

It must also be regarded as an advantage that the novel set of equipment requires smaller exposure, which results in a lower risk of infection and the quicker recovery of the patient.

It is also favourable that the supporting elements with a specifically constructed connection head can be fixed in the vertebra body in a way that the thread cannot become loose even in the case that the spine is loaded, which was a rather common problem in the case of the traditional versions.

Another advantage also due to the novel construction is that the use of the connection part- unit assembled from rod elements with specific ends also makes the already assembled and securely fixed set of equipment flexible to a certain extent, which reduces the risk of implant fracture, which used to be a common problem in the case of excessive loading, and the risk of other complications or undesired mechanical effects.

It must also be mentioned as an advantage that due to the use of rod elements the distance to be bridged is practically unlimited as well as the number and position of the supporting elements that can be connected to the connection part-unit, which significantly extends the field of use of the set of equipment.

An advantage deriving from the releasable connection between the threaded shaft and the connection head is that independent accommodation cavities can be created on both top surfaces and independent rod elements can be attached to them, and in this way with one single connection element a nodal point realising multidirectional power transmission can be created. This structural construction is also suitable for placing several rod elements next to each other going in the same direction, which makes it possible to increase of load-bearing capacity of a given section bridged over. Apart from fastening vertebrae together these advantages also make the set of equipment according to the invention suitable for fastening bone pieces together, so the construction itself can be used as an external bone fixing tool for optional interventions.

Below the invention is described in detail in connection with a construction example, on the basis of a drawing. In the drawing figure 1 is the side-view of a possible version of the set of equipment, partly in section, figure 2 is the top-view of a possible version of the set of equipment, figure 3 is the side-view of another construction of the set of equipment, partly in section, figure 4 is the top-view of the connection head as in figure 3.

Figure 1 is a version of the set of surgical equipment according to the invention, which shows the first supporting element 10, the second supporting element 30 and the rod element 21 belonging to the connection part-unit 20 situated between the two of them. The connection part-unit 20 consists of several rod elements 21, which are connected to each other with the help of the first supporting element 10 and the second supporting element 30. It must be pointed out here that the connection of the first supporting elements 10 and the second supporting elements 30 connecting the individual rod elements 21 is always the same, so the description of the present construction can be practically extended to the connection of an optional number of rod elements and supporting elements 10, 30.

Figure 1 shows that the supporting element 10 comprises the threaded shaft 11 and - in the case of the present construction - the connection head 12, which is made from the material of the threaded shaft 11 , forms one single unit with it and falls into the continuation of the inner end 1 lb of the threaded shaft. The threaded shaft has a thread l ie situated at its outer end 11a opposite the connection head 12. This thread l ie makes it possible to securely fix the supporting element 10 in the vertebral body not shown in the figured.

Practically the connection head 12 is cylinder shaped and is delimited by a cylindrical surface 13 and a top surface 17. The connection 12 head contains the accommodation zone 14, which in the present construction consists of the first accommodation hole 15 and the second accommodation hole 16. The first accommodation hole 15 is also surrounded by a cylindrical delimiting wall 15b, and in the cylindrical delimiting wall 15b there is a slot 15a extending out to the cylindrical surface 13 of the connection head 12, which slot 15a is parallel to the main axis l id of the supporting element 10.

The first accommodation hole 15 has an opening part 15c situated on the top surface 17 on the one part and a recess 15f on its end opposite the opening part 15c on the other part. Near the opening part 15c of the first accommodation hole 15 the delimiting wall 15b has a first connection piece 15d the task of which is to create a connection with the second connection piece 42 of the clamping body 41 of the clamping unit 40, which second connection piece 42 can be fitted in the accommodation hole 15 on the side of the opening part 15c. In the present case of the first connection piece 15d is a female thread, while the second connection piece 42 is a thread the dimensions of which suit the first connection piece 15d. The task of the recess 15f is to make locking with form possible due to its specific geometrical construction between the first connection body 21a of the rod element and the connection head 12.

The second accommodation hole 16 situated in the accommodation zone 14 of the connection head 12 of the supporting element 10 has a similar construction to the first accommodation hole 15, so it has a delimiting wall 16b, which also has a slot 16a, an opening part 16c, a first connection piece 16d situated near the opening part 16c and a recess 16f at the end of the second accommodation hole 16 opposite the opening part 16c.

The main axis 15e of the first accommodation hole 15 and the main axis 16e of the other accommodation hole 16 situated in the accommodation zone 14 of the supporting element 10 are parallel to the main axis l i d of the threaded shaft 11 of the supporting element 10.

The supporting element 30, as shown in figure I, has the same shape, construction and geometrical dimensions as the supporting element 10 described above. It also has a threaded shaft 31 on the outer end 31a there is a thread 31c, while the connection head 32 falls in the continuation of its inner end 31b. In this case too the connection head 32 is delimited by a cylindrical surface 33 and a top surface 37, and the connection head 32 also includes the accommodation zone 34. The accommodation zone 34 has a first accommodation hole 35 and a second accommodation hole 36. The first accommodation hole has a delimiting wall 35b, a slot 35a, a recess 35f, an opening part 35c and a first connection piece 35d situated near the opening part 35c. The other accommodation hole 36 has a delimiting wall 36b, a slot 36a, a recess 36f, an opening part 36c and a first connection piece 36d situated near the opening part 36c. The main axis 35e of the first accommodation hole 35 and the main axis 36e of the other accommodation hole 36 situated in the accommodation zone 34 of the supporting element 30 are also parallel to the main axis 3 Id of the threaded shaft 31 of the supporting element 30.

It must be pointed out here that it is not an obligatory requirement that main axis l id, main axis 15e and main axis 16e, and also main axis 31d, main axis 35e and main axis 36e should be parallel to each other, but angular deviation of more than 10° is not desirable.

Figure 1 also shows how the first rod element 21 of the connection part-unit 20 is situated between supporting element 10 and supporting element 30. Each rod element 21 comprises the first connection body 21a, the other connection body 21c and the spine member 21b connection the two of them to each other. In the present case the first connection body 21a and the second connection body 21c are both a space curve surface delimited by a spherical shell piece 2 Id, the dimensions of which space curve surface are adjusted to make the spherical shell piece 21 d of the first connection body 21a fit into the first accommodation hole 15 of the supporting element 10, and to make the spherical shell piece 21d of the second connection body 21c fit into the second accommodation hole 36 of the supporting element 30.

Figure 1 and figure 2 show that the spine member 21b of the rod element 21 of the connection part-unit 20 is a rod delimited by a cylindrical surface, the cross-section of which rod near the first connection body 21a is smaller than the free opening of the slot 15a belonging to the first accommodation hole 15 of the supporting element, and its cross-section near the other connection body 21c is smaller than the free opening of the slot 36a of the second accommodation hole 36 of the supporting element 30. In the case of the paired units: slot 15a - first connection body 21a and second connection body 21c - slot 36a the geometrical dimensions should be chosen to make it possible for the spine member 21b of the rod element 21 to turn or tilt freely in any direction around the intersection point of the main axis 21e of the spine member 21b and the main axis 15e of the first accommodation hole 15 as a centre, along an "α" cone angle of at least 25°. Figure 1 and figure 2 also show that the first connection body 21a of the rod element 21 is clamped in the first accommodation hole 15 of the accommodation zone 14 of the supporting element 10 in a way that the first connection body 21a is delimited by the delimiting wall 15b, the recess 15f and the clamping body 41 of the clamping unit 40. The secure fixation of the first connection body 21a is realised by the stressing force occurring between the edge of the recess 15f of the first accommodation hole 15 and the clamping unit 41, exerted on the first connection body 21a. The same stands for fixing the second connection body 21c into the supporting element 30. Here the second comiection body is delimited by the delimiting wall 36b of the second accommodation hole 36, its recess 36f and the clamping body 41 situated here. The fixation is realised by the force occurring between the edge of the recess 36f and the clamping body 41, exerted on the second connection body 21c.

Obviously the same type of connection — locking with force and form - can be realised between the rod element 21 that can be fitted in the second accommodation hole 16 of the supporting element 10 of the se of surgical equipment, and also between the rod element 21 fitted in the first accommodation hole 3 of the supporting element 30.

Figure 2 also shows that the clamping unit 40 of the supporting element 30 consists of two clamping bodies 41, one of which is placed in the opening part 35c of the first accommodation hole 35, and the other one is placed in the opening part 36c of the second accommodation hole 36. If the supporting element - supporting element 10 in our case - is in exterior position, obviously the clamping unit 40 only has one single clamping body 41, as in the case of the exterior supporting element 10 the rod element 21 forming a part of the connection part-unit 20 fits in only one of the accommodation holes - accommodation hole 15 in the present example - of the accommodation zone 14.

When using the set of surgical equipment according to the invention first the required number of supporting elements 10, 30 need to be fixed into the vertebral bodies with the help of the thread l ie of the threaded shaft 11. After this taking into consideration the distance between the neighbouring supporting element 10 and supporting element 30 the connection part-unit 20 needs to be created by selecting rod elements 21 of a suitable number and length. Then the rod elements need to be inserted between the two neighbouring supporting elements 10, 30 one by one, according to the following. The spherical shell part 2 Id of the first cormection body 21a of the rod element 21 is guided through the opening part 15c belonging to the first accommodation hole 15 - situated in the accommodation zone 14 of the connection head 12 - of the supporting element into the space part encased by the delimiting wall 15b, in a way that the part of the spine member 21b of the rod element 21 near the first connection body 21a goes through the slot 15a of the first accommodation hole 15. Then the first clamping body 41 of the clamping unit 40 is placed in the opening part 15c of the first accommodation hole 15, and with the help of the second connection piece 42 it is attached to the first connection piece 15d of the first accommodation hole 15. While twisting the clamping body 41 the paired unit consisting of the first connection piece 15d and the second connection piece 42 co-operate with each other as a result of which the clamping body 41 gradually sinks into the first accommodation hole 15 of the connection head 12 of the supporting element 10. When the clamping body 41 reaches the spherical shell piece 2 Id of the first connection body 21a situated in the first accommodation hole, it bears against it and pushes it in front of itself towards the recess 15f in the first accommodation hole 15.

When the spherical shell piece 21 d of the first connection body 21a reaches the recess 15f and bears against its edge, the twisting of the clamping unit 41 is stopped, and the second connection body 21c of the rod element 21 is fitted into the second accommodation hole 36 of the supporting element 30 in a way that the part of the spine member 21b of the rod element near the second connection body 21c goes through the slot 36a of the second accommodation hole 36 of the moving part-unit 30.

After placing the spherical shell piece 21d of the second connection body 21c into the second accommodation hole 36, another clamping body 41 is fitted in the opening part 36c of the second accommodation hole 36, and with the help of the paired unit consisting of the second connection piece 42 and the first connection piece 36d the spherical shell piece 21 d of the second connection body 21c is also forced into the second accommodation hole 36 in a way that the spherical shell piece 21d bears against the edge of the recess 36f of the second accommodation hole 36. Now pulling the clamping bodies 41 placed in supporting element 10 and supporting element 30 with the right force the spherical shell piece 21d of the first connection body 21a is clamped between the clamping body 41 screwed into the first accommodation hole 15 and the edge of the recess 15f, while the spherical shell piece 21d of the second connection body 21c is tightened by the clamping body 41 fitted into the second accommodation hole 36 and the recess 36f clamping it in a position where it cannot be displaced.

The fixation of the rod elements 21 is continued between the neighbouring supporting element 10 and supporting element 30 until the complete connection part-unit 20 is created. Then the tightened rod elements 21 can e positioned in any optional direction in space between supporting element 10 and supporting element 30 in a way that the individual rod elements 21 do not need to be exposed to deformation.

When the set of surgical equipment is disassembled, after loosening the clamping bodies 41 screwed into the individual supporting elements 10, 30 and removing them from the connection heads 12, 32 the rod elements 21 forming the connection part-unit 20 can be lifted out and the supporting elements 10, 30 can be taken out of the vertebral bodies.

Figures 3 and 4 show a construction of the set of surgical equipment according to the invention, in which supporting element 10 and supporting element 30 are constructed in a different way than described above. It can be seen that the threaded shaft 11 of the supporting element 10 and the connection head 12 are not made in one single piece. The thread l ie can be found on the outer end 1 la of the threaded shaft 11, but the inner end 1 lb of the threaded shaft 11 does not continue in the connection head 12, but it is a freestanding stick of a small cross-section. In accordance with this the inner end l ib of the threaded shaft 11 is guided through the opening 18 created in the connection head 12, and in this way the connection head 12 is connected to the threaded shaft 11 so that it can be slid in the direction of the main axis l id of the threaded shaft 11 and it can also be turned around the main axis of the threaded shaft 11. The opening 18 of the connection head 12 is situated in the aperture 19, which practically runs through the connection head 12 between the top surfaces 17 and extends out to the cylindrical surface 13 of the connection head 12.

Obviously the connection head 12 of the supporting element 10 also has an accommodation zone 14, which also includes the first accommodation hole 15. The first accommodation hole created in the connection head 12 - as described in detail in connection with the previous construction - is encased by a delimiting wall 15b, and it has a slot 15a extending out to the cylindrical surface 13 of the connection 12 as well as an opening part 15c extending out to the top surface 17 of the connection head, which opening part 15c, as the first connection piece 15d, is provided with a thread. The threaded second connection piece 42 of the clamping body is connected to the first connection piece 15d. In the case of this version of the invention too the clamping body 41 and the clamping body 41 ' - which can be seen at the other top surface 17 of the connection head 12 - together form the clamping unit 40.

It is also obvious that the first accommodation hole 15 and the second accommodation holes 16 - not shown in figure 3 - can also contain rod elements 21, the first connection body 21a of which is tightened into the first accommodation hole 15 or in one of the second accommodation holes 16, with the first clamping body 41 of the clamping unit 40.

The threaded shaft 31 of the supporting element 30 shown on the right side of figure 3 can also be separated from the connection head 32. However, in this case the connection head 32 is constructed differently as compared to the connection head 12 shown on the left side of figure 3. In the case of the connection head on the right 32 the clamping bodies 41 and 41' forming the clamping unit 40 can only be found on one of the top surfaces 37 of the connection head 32. At the same time on this connection head 32 a possible construction of the fixing part-unit 50, which fixes the threaded shaft 31 in the opening 38 of the aperture 39. The fixing part-unit 50 comprises the first fixing body 51 situated on one side of the aperture 39 and the second fixing body 52 situated on the other side of the aperture 39. In the present case the first fixing body 51 is a bolt, and the second fixing body 52 is a nut. The first fixing body 51 reaches the second fixing body 52 through a bore 53 made in the connection head 32. Obviously the nut can be replaced with a female thread cut into the material of the comiection head 32 on the given side of the aperture 39. And the fixing unit part-unit 50 itself can even be any suitably constructed mechanical structure, which is suitable for holding together the connection head 32 and the threaded shaft 31 in its given position in a way that they cannot be displaced.

Figure 4 shows the position of the first fixing body 51 and the second fixing body 52 of the fixing part-unit used for fastening the threaded shaft 31 and the connection head together 32, with respect to the opening 38 and the aperture 39. The use of the set of surgical equipment according to the invention is the same as described above, with the difference that the threaded shaft 11 containing a thread 1 lc screwed into the bone piece can be used independently. When the threaded shaft is in the desired position, the opening of the connection head 12 of the supporting element 10 is placed on the inner end 1 lb of the threaded shaft 11, and the connection head 12 can be pulled onto the threaded shaft 11 and it can be pushed down on it until the desired position is reached. When the connection head 12 reaches its position where it is fixed, with the use of the fixing part-unit 50 the two sides of the aperture 19 encasing the opening 18 can be approached towards each other. As aperture 19 becomes smaller, the opening becomes smaller too, and in this way the threaded shaft 11 is tightened into the narrowing opening 18. Then the rod elements belonging to the connection head 12 can also be fixed with the clamping bodies 41 of the clamping unit 40, and the set of surgical equipment forms a fixed-angle supporting structure of the required form.

The set of surgical equipment according to the invention can be advantageously used for the necessary fixation of the vertebral bodies of the spine, and it can also be used in the case of other bone surgery procedures, where the securely fixed position of the bone pieces with respect to each other needs to be ensured, e.g.: in the case of external bone fixing tools.

List of references

first supporting element 1 1 threaded shaft 1 la outer end 1 lb inner end l ie thread l id main axis 12 connection head 13 cylindrical surface 14 accommodation zone 15 first accommodation hole 15a slot 1 5b delimiting wall 15c opening part 1 5d first connection piece 1 5e main axis 1 5f recess 16 second accommodation hole 1 6a slot 1 6b delimiting wall 16c opening part 16d first connection piece 1 6e main axis 16f recess 17 top surface 1 8 opening 19 aperture

connection part-unit 21 rod element 21a first connection body 21b spine member 21c second connection body 21 d spherical shell piece 21 e main axis second supporting element 3 1 threaded shaft 31a outer end 31b inner end 3 1c thread 3 1 d main axis 32 connection head 33 cylindrical surface 34 accommodation zone 35 first accommodation hole 35a slot 35b delimiting wall 35c opening part 35d first connection piece 35e main axis 35f recess 36 second accommodation hole 36a slot 36b delimiting wall 36c opening part 36d first connection piece 36e main axis 36f recess 37 top surface 38 opening 39 aperture0 clamping unit 41 clamping body 42 second connection piece0 fixing part-unit 51 first fixing body 52 second fixing body 53 bore

'α" cone angle

Claims

1. Set of surgical equipment for the fixing of bone pieces, especially for maintaining the positions of vertebrae as compared to each other, which contains supporting elements that each have a threaded shaft that can be screwed into the bone to be fixed and a connection head connected to the threaded shaft, as well as a connection part-unit inserted between the connection heads of the supporting elements, the connection heads of the supporting elements are delimited by a cylindrical surface and a top surface, the connection heads have an accommodation zone suitable for connecting the connection part-unit and a clamping structure fixing the connection part-unit in the accommodation zone, in at least a part of the connection head of the supporting elements the accommodation zone has accommodation holes and slots extending out from the accommodation holes to the cylindrical surface of the connection head and opening parts extending to the top surface of the connection head, the connection part-unit is formed by a set of rod elements that each have a first connection body, a second connection body and a spine member connecting these two, the first connection body and the second connection body of the rod elements positioned between the two supporting elements are at least partially delimited by a space curve, in a practical case by a spherical shell part, furthermore, the one connection body of the rod element connecting two neighbouring supporting elements is fitted into the accommodation hole of the accommodation zone of the connection head belonging to the one supporting element, while the other connection body of the rod element is fitted into the accommodation hole of the accommodation zone of the connection head belonging to the other supporting element, the part of the spine member of the rod element in the proximity of the one connection body is guided through the slot of the accommodation hole of the one supporting element, and the part of the spine member of the rod element in the proximity of the other connection body is guided through the slot of the accommodation hole of the other supporting element, and it is in this way that two neighbouring supporting elements are connected to one another, characterised by that in at least a part of the connection heads (12, 32) one of the accommodation holes (15, 35) of the accommodation zone (14, 34) is combined with one or more other accommodation holes (16, 36) independent from it, on the part of the delimiting wall (15b, 16b, 35b, 36b) between the first accommodation hole (15, 35) and the second accommodation hole (16, 36) near the top surface (17, 37) of the connection head (12, 32) there are first connection pieces (15d, 16d, 35d, 36d) independent from each other, and the clamping unit (40) is formed by a group of independent clamping bodies (41) that are allocated to the first connection pieces (15d, 16d, 35d, 36d) separately, can be connected to the first connection pieces (15d, 16d, 35d, 36d) in a displaceable way and are provided with a second connection piece (42) co-operating with the first connection pieces (15d, 16d, 35d, 36d).

2. Set of surgical equipment as in claim 1, characterised by that in at least a part of the supporting elements (10, 30) the first accommodation hole (15, 35) and/or the second accommodation hole (16, 36) has a cylindrical delimiting wall (15b, 16b, 35b, 36b).

3. Set of surgical equipment as in claim 1 or 2, characterised by that in at least a part of the supporting elements (10, 30), at the end of the first accommodation hole (15, 35) and/or the second accommodation hole (16, 36) opposite the opening part (15c, 16c, 35c, 36c) there is a recess (15f, 16f, 35f, 36f) extending into the supporting element (10, 30).

4. Set of surgical equipment as in any of claims 1 -3, characterised by that the main axis (15e, 35e) of the first accommodation hole (15, 35) and the main axis (16e, 36e) of the second accommodation hole (16, 36) of the individual supporting elements (10, 30) are at a maximum angle of 10° with respect to each other, favourably they are parallel to each other.

5. Set of surgical equipment as in any of claims 1-4, characterised by that the first connection piece (15d, 16d, 35d, 36d) and the second connection piece (42) are screw threads.

6. Set of surgical equipment as in any of claims 1-5, characterised by that the threaded shaft (1 1, 31) and the connection head (12, 32) of the supporting element (10, 30) are made in one piece.

7. Set of surgical equipment as in any of claims 1-5, characterised by that the connection head (12, 32) of the supporting element (10, 30) is provided with an opening (18, 38) for guiding through at least a part of the threaded shaft (11, 31), and a part of the threaded shaft (11, 31) is clamped in the opening (18, 38).

8. Set of surgical equipment as in claim 7, characterised by that the connection head (12, 32) of the supporting element (10, 30) is provided with an aperture (19, 39) running between the opening (18, 38) and the cylindrical (13, 33) surface of the connection head (12, 32).

9. Set of surgical equipment as in claim 7 or 8, characterised by that the connection head (12, 32) of the supporting element (10, 30) is combined with a fixing part-unit (50) containing the first fixing body (51) and the second fixing body (52), and the first fixing body (51) of the fixing part-unit (50) is situated on one side of the aperture (19, 39), while the second fixing body (52) of the fixing unit (50) is situated on the other side of the aperture (19, 39).

10. Set of surgical equipment as in any of claims 1-9, characterised by that the main axis (15e, 35e) of the first accommodation hole (15, 35) and the main axis (16e, 36e) of the second accommodation hole (16, 36) of the individual supporting elements (10, 30) and the main axis (l id) of the threaded shaft (11, 31) of the supporting element (10, 30) are at a maximum angle of 10° with respect to each other, favourably they are parallel to each other.