WO2004021895A2

WO2004021895A2 - Surgical device for the separation of bony tissue

Info

Publication number: WO2004021895A2
Application number: PCT/EP2003/008857
Authority: WO
Inventors: Rainer HÄUSLER; Ralf Baumunk; Frank Eiben; Ludger Kirsch; Hartmut Louis; Joachim Möllmann; H.-J. Mühlhausen; Frank Pude; Stephan Schmolke
Original assignee: Aesculap Ag & Co. Kg
Priority date: 2002-09-04
Filing date: 2003-08-08
Publication date: 2004-03-18
Also published as: AU2003255405A1; AU2003255405A8; DE10240654A1; WO2004021895A3

Abstract

The invention relates to a surgical device for the separation of bony tissue, by means of a fluid stream, optionally containing abrasive particles with a high pressure source for generation of the fluid stream and with a jet device for directing the fluid stream against the bony tissue for separation. According to the invention, a protection against undesired effects of the fluid stream may be achieved, whereby the device has a closed housing enclosing the bony tissue for separation on all sides, with a sealed inlet for the jet device and a collector device for the fluid directed against the bony tissue from the jet device.

Description

SURGICAL DEVICE FOR TRANSPARING BONE TISSUE

The invention relates to a surgical device for severing bone tissue by means of a liquid jet which may contain abrasive particles, with a high-pressure source for generating the liquid jet and with a jet device which directs the liquid jet against the bone tissue to be severed.

In a large number of surgical operations, bone tissue has to be severed, for example when inserting an artificial knee joint. It is known to carry out this cutting of the bone tissue by means of oscillating saws, with which plane cuts can be made in the bone tissue. However, the quality of these cuts is sometimes unsatisfactory, since deformation of the saw blades can result in deviations from the desired flat geometries.

It is also known to cut bone tissue by directing liquid jets against the bone tissue under very high pressure, these liquid jets then cutting through the bone material. The separating effect can be increased by adding abrasive particles to the liquid jet, in particular abrasive particles soluble in the liquid, which are present in the liquid jet as solid abrasive particles during the severing process, but which dissolve in the liquid after being separated and therefore do not form any residues in the operating area (DE 198 04 065 AI). It has also been proposed to use liquid jets of this type, which operate at pressures of the order of 1000 bar, for severing bone tissue along a surface which is not planar but which is, for example, spherical, so that bone structures severed along such a surface are relatively can be adjusted to each other, for example to correct an incorrect position (DE 101 19 328.9). It has also been proposed to protect sensitive parts of the body against undesirable injuries caused by the liquid jet by means of a spoon-like shielding instrument, which is also intended to reduce the kinetic residual energy of the liquid jet after the bone tissue has been severed.

The known methods have not yet been able to be put into practice because difficulties of the most varied kind can arise when using such liquid jets in the operating area. The operating personnel can be injured by the liquid jet or by the particles accelerated by it, the same applies to the patient himself, liquid splashing around can contaminate the operating room, the noise pollution is extremely high, etc.

It is an object of the invention to design a generic device in such a way that the method for severing bone tissue by means of a high-pressure liquid jet can be used without problems in the operating room.

This object is achieved according to the invention in a device of the type described in the introduction in that it comprises a closed housing which surrounds the bone tissue to be severed on all sides and which comprises a housing sealed access for the jet device and a collection device for the liquid directed by the jet device against the bone tissue.

A housing which is closed in this way limits the area which comes into contact with the liquid jet and the liquid to the interior of this housing and thus protects the surroundings, the housing has a noise-dampening effect and at the same time collects the liquid used to sever the bone tissue, so that these is removed from the actual operating area. This makes it possible to use this method in the operating room without the problems described continuing to occur.

It is advantageous if the housing has at least one sealed entry opening for a body part which contains the bone to be severed. For example, an entry opening for inserting a leg can be provided, it is also possible to provide such sealed entry openings at opposite ends, so that, for example, only the knee joint area of one leg is arranged inside the housing, but the leg protrudes from the housing on both sides ,

The access for the jet device and / or the inlet opening for a body part can be sealed by means of a flexible sleeve which surrounds the jet device or the body part in a tight fit. Such a flexible sleeve can be formed, for example, by a flexible film, which is applied tightly to the radiation device or the body part by means of an elastic limitation or by means of a thread and which is connected directly to the walls of the housing. In this way, the beam device and body part can be oriented as desired relative to the housing. The access for the jet device can be designed such that a device emitting the jet itself dips into the housing through this access, but it can also be provided that only supply lines are passed through this access if the actual dispensing device for the liquid jet is inside of the housing is arranged.

The collecting device preferably comprises a collecting container at the bottom of the housing. This can be provided with a discharge line, so that liquid is already discharged from the housing during the severing process, thereby preventing the level of the liquid in the housing from rising and possibly reaching the body part.

It is advantageous if the top of the collecting container is covered by a perforated cover, for example a perforated plate. A clear separation of the collecting container from the rest of the interior of the housing can thereby be achieved; the body part is supported in this remaining interior.

It is advantageous if the housing is at least partially transparent, so that the course of the operation can be observed.

The inside of the housing can be provided at least in some areas with a coating that prevents the adherence of liquid and tissue particles, for example an anti-fog coating, a "Lotus" coating known per se or another non-stick coating, so that contamination on the inside of the housing is also possible avoided becomes like an increase in transparent areas, the visibility of the interior of the housing is preserved.

In a particularly preferred embodiment of the invention it is provided that the housing is assembled modularly from individual parts. In the simplest case, the housing comprises a base plate and an upper part which can be placed thereon in the form of a hood. This makes it possible to arrange the body part to be treated above the base plate on the operating table, to carry out the necessary surgical steps on the body part and only to close the housing when the body tissue is to be severed by placing the top part on the base plate , As a result, the housing does not hinder the surgeon in the necessary surgical steps that precede the actual cutting of the bone tissue or that follow.

In particular, it can be provided that a base plate, side walls and a cover are designed as independent components which can be joined together to form a closed housing, it is advantageous if the individual parts of the housing can be pushed together or plugged together via a tongue and groove system. The surgeon can then build a completely closed housing in a very short time after completing the preparatory surgical steps by inserting the side walls into the base plate and by fitting a cover, which can also be adapted to the size of the operating area or by appropriate orientation of the modular components, for example to a left or right knee. It is also possible, for example, to design a side wall in two parts, so that it seals from one side of a body part. can be pushed, which enters the interior of the housing in the region of this side wall.

It is particularly advantageous if a base plate of the housing comprises a lower part and an upper part, which can be fitted together in a precisely fitting manner by adjusting members. In this case, the base plate consists of two superimposed parts which can be separated from one another and which can be positioned relative to one another by the adjusting members.

In particular, the adjusting members can comprise recesses and projections which plunge into them, for example holes and pins which engage in them.

A sterile cover can be arranged between the lower part and the upper part, for example in the form of a sterile cloth, which covers the lower part and onto which the upper part can be placed.

In particular, the adjusting members can pass through the sterile cover, which can have corresponding openings for this purpose.

It is envisaged that the housing consists of a sterilizable material.

In a further preferred embodiment, a base plate of the housing carries a holding device, by means of which the base plate can be fixed on an operating table. This holding device can be, for example, a clamping device or a screwing device. This makes it possible to fix the base plate on the operating table, plate then the remaining housing parts are then fixed so that the entire housing is firmly connected to the operating table in this way.

It is advantageous if a fixing device for storing and fixing the bone tissue to be severed is fixedly arranged on the bottom of the housing. During the operation, the bone tissue to be treated is therefore fixed in the fixing device on the bottom of the housing, which is fixed at the operating table before the operation, so that the preparatory surgical steps can be carried out. The fixing device remains on the floor when the housing is completed and closed and also fixes the bone tissue to be treated during the severing by the liquid jet.

In particular, the fixing device can be designed in the manner of an external fixator, that is to say work using pins which engage in the bone and external supporting rods which fix the pins in certain positions relative to one another.

In a further preferred embodiment, the interior of the housing is connected to a suction device which exits the liquid above the collecting device. By means of this suction, aerosols and droplets can be sucked out of the atmosphere of the interior of the housing, in particular the suction can be arranged in such a way that a laminar flow takes place in the interior of the housing, which ensures that aerosols and liquid droplets are continuously transported away and thus the interior and also that Keeps the surgical area free from these potentially disturbing phenomena during the separation process. The exit point of the suction is preferably opposite the access for the jet device.

It is also advantageous if the exit point of the suction is arranged approximately halfway up the housing, so that the entire interior of the housing is influenced by the suction in substantially the same way.

According to a further preferred embodiment, at least one impact surface is arranged in the housing, which the liquid jet strikes after severing the bone tissue and to which it releases its kinetic residual energy.

This baffle can, for example, run parallel to a side wall, preferably at a distance therefrom, so that the liquid droplets flow off after passing through the baffle on this side wall and can collect in the collecting device on the underside of the housing.

It is advantageous if the impact surface is formed by lamellae inclined with respect to the jet direction or is constructed in a honeycomb shape, the particles of the liquid jet are thereby forced to change direction suddenly and thereby release their kinetic energy to the impact surface.

In particular, two or more impact surfaces with differently inclined structures can be arranged next to one another, so that a labyrinthine passage is created for the liquid particles. The baffles can be pushed into the housing so that they can be replaced in a simple manner if signs of wear should occur.

It is also advantageous if, in addition to the baffle, a suction device emerges from the housing, so that part of the liquid braked on the baffle surfaces is already removed from the housing via this suction device; the same applies to possible abrasion particles caused by the impact of the liquid jet on the Baffle can be released from this.

The impact surface consists of an abrasion-resistant, biocompatible material, for example of a ceramic, in particular of an aluminum oxide or zirconium oxide ceramic.

In a further preferred embodiment of the invention it is provided that for determining the relative positioning of the bone tissue to be cut and the beam device a navigation system is provided with marking elements which are fixed on the one hand on the bone tissue to be cut and on the other hand on the beam device.

Navigation systems of this type are known per se; they determine the position of the marking elements in space, for example via a camera system which has a plurality of cameras and which works with infrared radiation which is emitted by the marking elements or reflected on them. If the marking elements are firmly connected to a specific object, for example the bone tissue or the beam device, their positions and orientations in space can be precisely determined by the navigation system. be correct, and thus also the relative position between the bone tissue on the one hand and the beam device on the other.

The beam device can be directly or indirectly firmly connected to the bone tissue to be severed and can be displaced in a defined manner relative to it. For example, the blasting device could be held directly on the bone tissue, e.g. by screwing, or also on the fixing device that fixes the bone in the housing. The jet device then has a defined, movable jet delivery element which can be displaced, for example, along a guide, so that the liquid jet can be moved relative to the bone.

In another embodiment it is provided that the beam device is freely displaceable relative to the housing and the bone tissue fixed therein and is displaceable by a control relative to the bone tissue to be severed. There is therefore no guide for the beam device that is firmly connected to the bone tissue, but the relative displacement of the beam device with respect to the bone tissue is carried out solely by the control that shifts the beam device in space with respect to the fixed bone tissue.

The beam device can, for example, be held on a movement robot, but it would also be possible to move the beam device along a template or even manually, in which case the surgeon controls the relative positioning of the beam device to the bone tissue via the navigation system. When using a motion robot, it is advantageous if it has a multi-articulated robot arm on which the beam device is held. This makes it possible to change the position of the beam device relative to the bone tissue in a very varied manner.

It is advantageous if the movement robot is arranged on a device which comprises supply units for the beam device and / or the housing. These supply units can be used to store and supply abrasive particles, but also to dispose of the liquid after the cutting process.

For example, a storage container and / or a metering device for an abrasive additive can be provided on the device, a suction device for suctioning the housing and / or a collecting container for liquids or solids removed from the housing, for example bone particles, abrasion particles, body fluids, cutting fluids or not yet dissolved abrasive particles.

It is advantageous if the device can be moved so that it can be positioned in a suitable manner relative to the operating table.

The following description of preferred embodiments of the invention serves in conjunction with the drawing for a more detailed explanation. Show it:

Figure 1 is a schematic representation of an operation site

Performing knee surgery; FIG. 2: an exploded view of the housing surrounding the operating area;

Figure 3 is a longitudinal sectional view through the closed housing of the

Figure 2 during knee surgery;

Figure 4 is a sectional view of the housing of Figure 3 from above;

Figure 5 is a cross-sectional view of the housing of Figure 3;

FIG. 6: a schematic representation of a femoral head when performing an anterior femoral incision;

Figure 7 is a view similar to Figure 6 when performing a front bevel cut;

Figure 8 is a view of the femoral head of Figures 6 and 7 after making the anterior femoral cut, the front bevel cut and the distal femoral cut;

Figure 9 is a view of the femoral head of Figures 6 to 8 in the

Implementation of the posterior femoral cut with the help of an additional impact element and

Figure 10: a view of the femoral head of Figures 6 to 9 with attached femoral prosthesis. The invention is discussed below using the example of the implantation of an endoprosthesis at the distal end of the femur, that is to say in the knee area, but it goes without saying that the device according to the invention can also be used on other parts of the body where it is necessary to sever bone tissue.

To perform the surgical operation mentioned, an operating table 1 is used, on which a patient 2 is placed, on whose leg 3 an endoprosthesis is to be inserted in the area of the knee.

First, a base plate 4 is attached to the operating table 1. This consists of a frame-shaped lower part 4b and an upper part 4a which can be placed thereon and which can be fitted onto the lower part 4b with a precise fit. For this purpose, the lower part carries upwardly protruding adjustment pins 4c which can engage in corresponding openings on the underside of the upper part 4a.

A clamping device 5 is arranged on the lower part 4b, with the aid of which the base plate 4 can be clamped to a clamping strip 6 of the operating table 1.

The division of the base plate 4 into the upper part 4a and lower part 4b makes it possible to arrange a sterile cover in the form of a sterile cloth 4d between the lower part and the upper part. After assembly of the lower part 4b, this sterile cloth is spread over the lower part 4b with the aid of the clamping device 5, the adjusting pins 4c projecting through corresponding openings in the cloth 4d. From above, the upper part 4a is placed so that the Engage adjusting pins 4c in corresponding openings on the underside of the upper part 4a, so that the upper part 4a and lower part 4b are brought together in an exact position, with the interposition of a sterile cloth 4d.

In the exemplary embodiment shown, the base plate 4 has a rectangular shape and only covers part of the operating table 1. In the base plate 4 there is a receiving chamber 7 which is open towards the top and is covered on its top by a perforated plate 8. The receiving chamber 7 is connected to a discharge line 9, through which liquid which enters the receiving chamber 7 through the perforated plate 8 can be removed from the receiving chamber 7.

On the base plate 4, two parallel clamping rails 10, 11 are also attached, which extend along the base plate 4. On these clamping rails 10, 11 support rods 13 are fixed by means of clamping shoes, which in the manner of an external fixator form a support frame 14 with fixation pins 15, these fixation pins 15 serve as holding elements for the leg 3 of the patient 2, for this purpose they are inserted laterally into the leg , penetrate the soft tissue and fix the bones in the leg 3 relative to the support frame 14 and thus relative to the base plate 4 and the operating table 1.

Four side walls can be placed on the base plate 4 along the outer edge thereof, namely a front wall 16, a rear wall 17, an end wall 18 and a push-through wall 19. These four walls can be inserted vertically into corresponding receiving grooves 20 in the base plate 4 and at their edges to the adjacent wall connected by a tongue and groove guide, which is not shown in the drawing. A cover plate 21 is placed on the walls of the same height, which is also via a groove Spring system is connected to these side walls. The base plate 4, the front wall 16, the rear wall 17, the end wall 18, the push-through wall 19 and the cover plate 21 together form a cuboid, closed housing 22 which surrounds the support frame 14 on all sides.

The walls consist of a sterilizable material, for example stainless steel, they can also consist of a transparent material, for example glass, or be at least partially transparent, so that observation of the interior 23 of the housing 22 is possible.

In the front wall 16 of the housing 22, a larger opening 24 is arranged, which is closed by means of a flexible film 25, in the middle of which a flexible sealing ring 26 is held. This sealing ring 26 surrounds a film-free push-through opening 27 for a blasting head 28 of a blasting device 29 described in more detail below.

The push-through wall 19 has a large opening 30 which is open towards the bottom, this opening 30 serves as a push-through opening for the leg 3 of the patient 2. This opening 30 is suitably sealed against the leg 3 of the patient 2, this is in the drawing shown only very schematically. For example, this can be done by a flexible sealing insert 31, which surrounds the leg 3 of the patient 2 in a tight manner on all sides and which is inserted sealingly into the opening 30 when the push-through wall 19 is inserted into the base plate 4 from above. However, it would also be possible to provide a film or thin-walled flexible sleeve in a similar manner to the opening 24, the push-through wall could also be formed in two parts and be attached to the leg 3 with a flexible sleeve from both sides, here are different Possibilities given to ensure a sealing connection between the push-through wall 19 and the leg 3.

The cover plate 21 and the end wall 18 of the housing 22 are continuous, so that the housing 22 communicates with the surroundings only through the push-through opening 27, the opening in the sealing insert 31, the suction 32 and the discharge line 9.

In the rear wall there is a suction device 32, which is connected to a suction hose 33, approximately halfway up in the middle thereof. The suction 32 emerges in the region of a depression 34 of the rear wall 17, and this depression 34 receives two baffle plates 35 and 36 which run parallel to the rear wall 17 and which leave a space 37 between them and the rear wall 17. In the embodiment of Figure 5, the two baffles 35 and 36 are each formed by parallel, arranged obliquely to the base plate 4 slats 38, 39, the inclination of the slats 38 and 39 in the adjacent baffle plates 35 and 36 is chosen opposite, so that between the Slats 38 and 39 form a labyrinthine passage. The baffle plates 35, 36 are approximately opposite the opening 24 in the front wall 16.

In the illustrated embodiment, the baffle plates 35, 36 are formed by mutually parallel slats 38 and 39, these baffle plates 35, 36 could also each be honeycomb-shaped, these honeycombs being inclined to the surface of the baffle plates 35, 36 in adjacent baffle plates preferably different. This also creates a labyrinthine passage through the two baffle plates. The baffle plates consist of an abrasion-resistant, biocompatible material, for example of Al ₂ O ₃ or ZrO ₂ .

In addition to the operating table 1, a mobile device 40 is arranged, which has a suction unit 41 and a liquid collection container 42 in its interior, the discharge line 9 opens into this liquid collection container, and also the suction hose 33 via the suction unit 41.

A robot arm 43 with a plurality of arm sections 44, 45, 46, 47 which can be moved relative to one another is arranged on the upper side of the device 40; this robot arm 43 is moved by a controller 48 inside the device 40. This robot arm 43 carries at its free end the jet device 29 which is essentially formed by a nozzle which is supplied with a liquid under very high pressure via a hose 50. This liquid is fed to the jet device 29 from a high-pressure unit, not shown in the drawing, under very high pressure, for example the pressure can be 1000 bar. The liquid is preferably water.

In the device 40 there is also a storage container 51 which can be combined with a metering device. In this storage container there is an abrasive additive which is soluble in the liquid, for example sugar compounds as described in DE 198 04 065 AI. This reservoir 51 is connected via a hose 49 to the jet device 29 in such a way that abrasive additives are sucked in by the liquid in the jet device 29 and mixed in the jet device 29 with this liquid, the jet head 28 of the jet device 29 thus releases a mixture of liquid under very high pressure, in particular water, and abrasive particles.

In the illustration in FIG. 1, a navigation system 52 is also shown very schematically, which comprises a plurality of cameras 53, a data processing system 54 and a monitor 55. The data processing system 54 is connected to the controller 48 via a connecting line 56, this connection can optionally also be made wirelessly. The navigation system 52 further comprises marking elements 57 and 58, the marking element 57 is firmly connected to the beam device 29, the marking element 58 is firmly connected to the leg 3 of the patient 2 or to the support frame 14 or the housing 22. All these parts are rigid connected to one another, so that in any case the marking element 58 is directly or indirectly rigidly connected to the leg 3 of the patient 2, while the marking element 57 is rigidly connected to the beam device 29.

The navigation system 52 determines the position and the position of the marking elements 57, 58 in space in a manner known per se, for example by infrared radiation, which is reflected on the marking elements 57, 58 and can be recorded by the cameras 53. This allows the relative position of the beam device 29 with respect to the leg 3 of the patient 2 to be determined exactly.

It is of course possible to use several such marking elements for determining the position of the leg 3, which can be fixed, for example, by means of bone screws on a bone of the leg 3, additionally on the support frame 14 and on the housing 22, so that there is additionally control over the position of these items. This also makes it possible, for example, lent to determine the position of the leg 3 via a marking element on the leg before closing the housing, but then indirectly via the position determination of the marking element on the housing.

The use of the described surgical device is explained below using the example of the preparation of the distal end 59 of a femur 60, this preparation is necessary in order to place an endoprosthesis 62 replacing the original articular surfaces 61 of the femur 60 on the distal end of the femur 60.

For this operation, the base plate 4 is first attached to the operating table 1 by means of the clamping device 5, the discharge line 9 and the suction hose 33 can already be connected to the device 40. During this preparatory phase, the device 40 is moved away from the operating table 1 in order to allow free access to the operating table 1.

The support frame 14 is built up on the base plate 4, and the patient 2 is now positioned so that his leg 3 is arranged above the support frame 14 in the flexion position, in this position both the thigh and the lower leg of the patient 2 are fixed by the fixation pins 15 of the support frame 14 set.

Access to the leg 3 is completely free, since so far only the base plate 4 with the support frame 14 has been arranged on the operating table 1.

In this position, the surgeon can open the leg 3 through preparatory surgical steps so that there is free access to the distal end of the femur 60 and in particular with regard to the articular surfaces 61 to be replaced (FIG. 3).

Only after completion of these preparatory surgical steps is the housing 22 then completed, that is to say the front wall 16, the rear wall 17, the end wall 18 and the push-through wall 19 are inserted into the base plate 4, in the manner described a sealing of the leg 3 in the area the opening 30 is produced, for example by a flexible sleeve. Finally, the housing 22 through the cover plate

21 tightly closed.

In a next step, the device 40 is moved towards the housing 22 in such a way that the jet device 29 can be pushed through the through opening 27 and with its nozzle into the interior 23 of the housing

22 protrudes (Figure 5).

The navigation system 52 can precisely determine the relative position of the beam device 29 relative to the femur 60 fixed to the support frame 14.

The data of the femur 60 can be obtained differently in a manner known per se. For example, it is possible to generate a three-dimensional data record by means of sectional image recordings using computer tomography, which data record is stored in the data processing system 54 and is made visible on the monitor 55. The respective position of the beam device 29 can be superimposed on this display of the monitor 55, so that the operator can recognize the relative positioning on the monitor 55. In another method, the data of the femur 60 are determined before the operation, specifically before the leg 3 is fixed on the support frame 14. In this case, for example, by using several marking elements on different parts of the leg, movement of the leg can be determined in a dynamic way , where the centers of the joints lie in the hip, knee and ankle, reference lines can be determined from this data, which are then used for the arrangement of sectional planes. In this case too, the data obtained in this way are fed into the data processing system 54 and stored there, so that during the operation, the surgeon can then use the monitor 55 to recognize precisely the relative position of the beam device 29 relative to the femur 60 or the severing planes determined in this way.

The data processing system can control the robot arm 43 via the control 48 in such a way that the direction of the beam emitted by the beam device 29 relative to the femur 60 is exactly maintained, and this setting is continuously checked and, if necessary, corrected via the navigation system 52. As soon as the correct starting position has been achieved, the jet device 29 is supplied with liquid under high pressure by the high-pressure unit, this liquid contains abrasive particles in the manner described and is directed in the form of a sharply focused liquid jet against the femur 60 in such a way that the latter upon impact of the liquid particles and the abrasive particle is severed.

After severing, the liquid jet hits the baffle plates 35, 36 with still high energy and high pressure, changes its direction of flow several times and releases its energy to the baffle plates 35 and 36, so that the liquid parts pass through the baffles 35 and 36 then get into the space 37 and flow down from there, from there they are partly removed by the suction 32, partly they run on the side walls and collect in the receiving chamber 7, both via the suction hose 33 and the liquid particles then also reach the liquid collection container 42 of the device 40 via the discharge line 9 and remain there until the end of the operation.

The robot arm 43 is now controlled via the controller 48 such that the liquid jet 63 prepares the distal end 59 of the femur 60 for the reception of the endoprosthesis 62. First of all, an anterior femoral incision is made on the exposed distal end 59 of the femur 60 (FIG. 6), followed by a front oblique incision (FIG. 7), followed by a distal femoral incision, so that the distal end 56 of the femur 60 is three each Cutting planes 64, 65 and 66 inclined at 45 ° to the adjacent plane are produced (FIG. 8).

The distal cutting plane 66 is followed by two further cutting planes 67 and 68, which are also inclined by approximately 45 ° with respect to the adjacent planes. In order to be able to perform the posterior femoral cut for the cutting plane 68, care must be taken at the same time that the femur 60 and also the surrounding soft tissue are not damaged, and for this purpose a plate-shaped impact element 69 next to the femur 60 is made before the posterior femoral cut is carried out inserted, whereby it runs approximately parallel to the femur and covers it posteriorly (FIG. 9). In the impact element 69, which consists of biocompatible and wear-resistant material, for example made of Al ₂ O ₃ - or ZrO ₂ ceramic - there are suction holes 70, which are not shown in the drawing channels inside the Impact element 69 are connected to a suction line 71, which in turn leads either to the suction hose 33 or directly to the suction unit 41 in the device 40. For this purpose, a sealed bushing can be provided on the housing 22, which is not shown in the drawing (FIG. 9).

The endoprosthesis 62 can then be placed covering the cutting planes on the distal end 59 of the femur 60 provided with five cutting planes 64 to 68, so that new articular surfaces 72 are thereby fixed on the femur 60.

The endoprosthesis 62 is put on after completion of the severing of the femur 60. As soon as this severing has been completed, the upper parts of the housing 22 can be removed again, leaving only the base plate 4 with the support frame 14 and the leg 3 attached to it back to the operating table 1, so that the surgeon again has free access to the distal end 59 of the femur 60 which has now been machined in the desired manner, he can then also put on the endoprosthesis 62 unhindered and complete the operation in the usual manner.

The individual steps required for such an operation for various variants of this operation are summarized below:

Variant I:

1. Preparatory measures 1.1 Position the patient on the operating table, if necessary create a tourniquet

1.2 Sterile washing and covering of the leg. The coverage depends on whether the hip is also covered, in this case no tourniquet is possible.

1.3 The operating table is covered with a special operating cloth, which has holes through which the upper part of the base plate can be attached to the operating table by means of the lower part of the base plate.

1.4 The base plate is attached to the operating table, together with the support frame.

operation start

2.1 The patient's leg is passed through the opening 30 of the push-through wall, but this is not yet inserted into the housing, but the leg is positioned and fixed on the support frame after being pushed through.

2.2 The knee is opened through a median skin incision and the access is extended over the distal third to display the femur. 2.3 Alternative: The leg can only be attached to the support frame after the knee has been opened.

2.4 The soft tissues are pulled apart with retractors so that there is free access to the distal end of the femur.

2.5 The front wall, the rear wall, the end wall, the push-through wall and the cover plate are assembled into a closed housing.

2.6 The beam device is inserted into the interior of the housing through the push-through opening.

2.7 Computed tomography images of the leg are shown on the monitor, as is the beam device. The beam device is shown in the correct position over the representation of the femur, the relative assignment is made via marker points (reference pins).

Femoral endoprosthesis with five levels of resection

3.1 The anterior femoral incision, the front oblique incision and the distal femoral incision are made one after the other, if necessary also the posterior oblique incision.

3.2 The additional impact element is inserted before or after the rear bevel cut, this can either be done after opening the Housing take place or through a further opening in the wall of the housing, which has a sealed reach-through opening in the manner of a chemical manipulator vessel, for example with the formation of a flexible glove.

3.3 The missing cuts are made.

3.4 The housing is removed, the cut pieces of bone are removed either after each saw cut or after all saw cuts have been made.

3.5 After removing the housing, the endoprosthesis is put on.

This is followed by conventional procedures for wound closure.

Variant II:

All process steps are the same, but the monitor does not show a three-dimensional data record of the bony structure obtained by computer tomography, but the geometric data of the leg are determined by bending the leg at various joints and by other movements before the leg is fixed on the support frame of the leg with the help of the navigation system and used to calculate preferred directions of the cutting planes to be produced.

Claims

PATENT CLAIM E

1. Surgical device for severing bone tissue (60) by means of a liquid jet (63) which may contain abrasive particles, with a high-pressure source for generating the liquid jet (63) and with a jet device (29) directed against the bone tissue (60) to be severed ), characterized in that it comprises a closed housing (22) which surrounds the bone tissue (60) to be severed on all sides and which has a sealed access (24) for the radiation device (29) and a collecting device (7) for the radiation device ( 29) has liquid directed against the bone tissue (60).

2. Device according to claim 1, characterized in that the housing (22) has at least one sealed inlet opening (30) for a body part (3) which contains the bone tissue (60) to be severed.

3. Device according to claim 1 or 2, characterized in that the access (24) and / or the inlet opening (30) by means of a flexible sleeve (25, 26, 27; 31) are sealed, which the jet device (29) or surrounds the body part (3) tightly.

Device according to one of the preceding claims, characterized in that the collecting device comprises a collecting container (7) on the bottom (4) of the housing (22).

Apparatus according to claim 4, characterized in that the collecting container (7) is provided with a discharge line (9).

Apparatus according to claim 4 or 5, characterized in that the collecting container (7) is covered on its top by a perforated cover (8).

Device according to one of the preceding claims, characterized in that the housing (22) is at least partially transparent.

8. Device according to one of the preceding claims, characterized in that the housing (22) is provided on its inside at least in regions with a coating preventing the adherence of liquid and tissue particles.

9. Device according to one of the preceding claims, characterized in that the housing (22) from individual parts (4, 16, 17, 18, 19, 21) is modularly assembled.

10. The device according to claim 9, characterized in that a base plate (4), side walls (16, 17, 18, 19) and a cover (21) are formed as independent components which can be joined together to form a closed housing (22).

11. Device according to one of claims 9 or 10, characterized in that individual parts (4, 16, 17, 18, 19, 21) of the housing (22) can be pushed together via a tongue and groove system (20).

12. The device according to one of claims 9 to 11, characterized in that a base plate (4) of the housing (22) comprises a lower part (4b) and an upper part (4a) which can be fitted together by adjusting members (4c).

13. The apparatus according to claim 12, characterized in that the adjusting members (4c) comprise recesses and protrusions immersed in them.

14. Device according to one of claims 12 or 13, characterized in that a sterile cover (4d) is arranged between the lower part (4b) and upper part (4a).

15. The apparatus according to claim 14, characterized in that the adjusting members (4c) pass through the sterile cover (4d).

16. Device according to one of the preceding claims, characterized in that the housing (22) consists of a sterilizable material.

17. Device according to one of the preceding claims, characterized in that a base plate (4) of the housing (22) carries a holding device (5) by means of which the base plate (4) on an operating table (1) can be fixed.

18. The apparatus according to claim 17, characterized in that the holding device (5) is a clamping device.

19. Device according to one of the preceding claims, characterized in that on the bottom (4) of the housing (22) a fixing device (14) for storing and fixing the bone tissue (60) to be severed is fixedly arranged.

20. The apparatus according to claim 19, characterized in that the fixing device (14) is designed in the manner of an external fixator.

21. Device according to one of the preceding claims, characterized in that the interior (23) of the housing (22) is connected to a suction device (32) which exits the liquid above the collecting device (7).

22. The apparatus according to claim 21, characterized in that the exit point of the suction (32) opposite the access (24) for the jet device (29).

23. Device according to one of claims 21 or 22, characterized in that the outlet point of the suction (32) is arranged approximately halfway up the housing (22).

24. Device according to one of the preceding claims, characterized in that in the housing (22) at least one baffle surface (35, 36) is arranged, on which the liquid jet (63) strikes after severing the bone tissue (60) and to which it is his releases kinetic residual energy.

25. The device according to claim 24, characterized in that the baffle surface (35, 36) runs parallel to a side wall (17).

26. The apparatus according to claim 25, characterized in that the baffle (35, 36) extends at a distance from the parallel side wall (17).

27. The device according to one of claims 24 to 26, characterized in that the baffle surface (35, 36) is formed by slats (38, 39) inclined with respect to the beam direction.

28. Device according to one of claims 24 to 26, characterized in that the baffle surface (35, 36) is honeycomb-shaped.

29. Device according to one of claims 24 to 28, characterized in that two baffles (35, 36) with differently inclined structures (38, 39) are arranged side by side.

30. Device according to one of claims 24 to 29, characterized in that the baffle (35, 36) in the housing (22) is held insertable.

31. The device according to any one of claims 24 to 30, characterized in that in addition to the baffle (35, 36), a suction (32) emerges from the housing (22).

32. Device according to one of claims 24 to 31, characterized in that the impact surface (35, 36) consists of an abrasion-resistant, biocompatible material.

33. Apparatus according to claim 32, characterized in that the baffle surface (35, 36) consists of ceramic, in particular of Al ₂ O ₃ or ZrO ₂ .

34. Device according to one of the preceding claims, characterized in that for determining the relative positioning of the bone tissue to be severed (60) and the beam device (29) a navigation system (52) is provided with marking elements (57, 58), on the one hand on the bone tissue (60) to be severed and, on the other hand, are fixed to the beam device (29).

35. Device according to one of the preceding claims, characterized in that the beam device (29) is directly or indirectly firmly connected to the bone tissue (60) to be severed and this can be displaced in a defined manner.

36. Device according to one of claims 1 to 34, characterized in that the beam device (29) relative to the housing (22) and the bone tissue (60) fixed therein can be moved freely and relative to the bone tissue (60) to be severed by a controller ( 48) is displaceable.

37. Apparatus according to claim 36, characterized in that the beam device (29) is held on a motion robot (43).

38. Apparatus according to claim 37, characterized in that the motion robot has a multi-articulated robot arm (43) on which the beam device (29) is held.

39. Apparatus according to claim 37 or 38, characterized in that the movement robot (43) is arranged on a device (40) which supply units (41, 42, 48, 51) for the beam device (29) and / or the housing ( 22) includes.

40. Apparatus according to claim 39, characterized in that a metering device for an abrasive additive is provided on the device (40).

41. Apparatus according to claim 39 or 40, characterized in that a reservoir (51) for an abrasive additive is provided on the device (40).

42. Device according to one of claims 39 to 41, characterized in that a suction device (41) for suction (32) of the housing (22) is provided on the device (40).

43. Device according to one of claims 39 to 42, characterized in that a collecting container (42) for liquid removed from the housing (22) is arranged on the device (40).

44. Device according to one of claims 39 to 43, characterized in that the device (40) is movable.