DE29880026U1 - Fixation system for a patient immobilization element - Google Patents

Description

PATENT ATTORNEYS

BESELERSTRASSE 4 D - 22607 HAMBURG

Orfit Industries Vosveld 9A

B-2110 Wijnegem Belgium

EUROPEAN PATENT ATTORNEYS EUROPEAN TRADEMARK ATTORNEYS DR.ULRICH GRAF STOLBERG (- 1998) OIPL.-ING. JÜRGEN SUCHANTKE DIPL.-ING. ARNULF HUBER DR. ALLARD von KAMEKE DIPL.-BIOL. INGEBORG VOELKER DR.PETER FRANCK DR. GEORG BOTH DR.ULRICH-MARIA GROSS DR.HELMUT van HEESCH DR. JOHANNES AHME DR.HEINZ-PETER MUTH DIPL.-ING. LARS MANKE DR.MARTIN WEBER

(G 48994 AH/wo) September 1998

Fixation system for a patient immobilization element field of use

This invention relates to a fixation system for a patient immobilization element, in particular a low temperature immobilization element.

Background of the invention

The immobilisation of a patient or part of the patient's body during radiotherapy, radiological examinations and/or radiodiagnostic examinations, or during stereotactic operations improves, on the one hand, the quality of these medical treatments and examination procedures as a result of increased effectiveness and accuracy and, on the other hand, increases the comfort for the patient.

State of the art

The systems available comprise, on the one hand, a covering layer material which is moulded over the patient, and, on the other hand, a base to which the moulded covering layer is connected. As a result, the patient and/or the relevant part of the patient's body is immobilised. The following is a description of systems in use today: a system using a hook-and-loop belt, in which the loop belt is pulled tight over the patient and attached to the hook belt on the base; a system using a so-called high temperature plastic material (HTTP) in which first a negative impression of the patient is taken using plaster, then a positive mould is made of plaster from this impression, and then the plastic is moulded over this positive mould by means of a vacuum moulding process. The resulting plastic element is then placed over the patient and connected to the base; a system using a thermosetting synthetic plaster bandage which is moulded over the patient and connected to the base; and also a system that uses a so-called "bite block" system in which on one side a small block is placed in the patient's mouth and the patient has to bite on this block and on the other side a connector is placed on the block which is connected to the base; a system in which a cushion is placed around the patient in a soft state and then hardened. This hardening can be done by chemical reaction of the contents of the cushion or by drawing air out of the cushion so that the remaining parts of the cushion become harder. This cushion is then attached to the base.

Currently, a system is widely used in which a so-called low-temperature plastic film (LTTP) is molded directly onto the patient in a soft state and then hardened to form a so-called

This soft state is achieved by placing the material in an environment with a relatively moderate working temperature. Various low-temperature plastic materials (low-temperature plastic materials) are available for these cover layers, as are various base molds or base plates to which the low-temperature plastic mold or cover can be attached.

Also known is a system in which a high-temperature plastic element is attached to a low-temperature plastic cover film, the element being in the form of a profile piece that remains hard during the activation of the LTTP material, the activation comprising the plasticization of the material. For the profile piece, existing high-temperature plastic materials and high-temperature curable plastic materials in combination with carbon fibers are used on the one hand.

However, the existing systems mentioned above have disadvantages, which are explained in order below.

In the first known system, the patient is only immobilized to a very limited extent, since this system is only two-dimensional and only surrounds a very limited area of the body part to be immobilized. This is because the hook belt has only a limited width.

The next system does not allow for direct immobilization of the patient. The system is labor intensive, time consuming to use, inconvenient for the patient and requires expensive equipment and a large number of people. Furthermore, the high-temperature plastic material cannot be remolded.

The chemical reaction of the other known system involves an exothermic reaction, which is unpleasant for the patient. Furthermore

different layers are formed unevenly on top of each other, resulting in differences in the thickness and density of the shape that interacts with the radiation, resulting in a loss of accuracy.
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The next known system is a two-dimensional shape that creates only a limited degree of immobility and is therefore uncomfortable for the patient.

The other known system is two-dimensional and large, where the chemical system produces an exothermic reaction and involves a laborious operating procedure and the vacuum system shows poor dimensional stability during successive uses, which is caused by the insufficient vacuum due to air entering the system.

The various existing systems using LTTP materials alone have the problem that the mold is only connected to the base part at two points, so the accuracy is not high enough. Two people are required to activate and form the low temperature plastic material. Another known system also requires two people. Because of the thickness tolerance in low temperature plastics, the attachment part does not always fit into the base part equally easily. In another system, two people are also required and it can only be used on one base part system. In the well-known case of a so-called U-frame, the so-called tent shape made of low temperature plastic means that the body part is not completely enclosed, so that it remains movable, which leads to a lack of accuracy.

Finally, for the last known case, the high-temperature plastic fixing profile piece can only be used on one system in each case. The fixing profile piece known here

has a relatively high density, which is a disadvantage in cases where the profile piece is in the irradiation field.

It was therefore firstly desired to eliminate the problem of the edges of the low temperature plastic cover sheet becoming soft during activation. To this end, these edges are made of a high temperature plastic material which remains hard during activation and can be fixed directly in or to the base plate while the low temperature plastic softens in the meantime. This resulted in a profile piece which is fixed to the low temperature plastic cover sheet on one side and fits into the base plate on the other side. The result was a fixing means which comprises on the one hand a one-piece profile piece made of low temperature plastic material and on the other hand a piece of high temperature plastic material which are permanently bonded together.

However, there are two significant limitations associated with this solution. Firstly, the shape of the one-piece profile piece can only be used on a single type of base plate.

Due to the fact that the profile piece is permanently connected to the low-temperature plastic covering layer, the use is further limited to the one low-temperature plastic material or the one low-temperature plastic form or covering layer to which the profile piece in question is attached.

Object of the invention
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It is an object of this invention to overcome the above-mentioned disadvantages.

Summary of the invention

To achieve this object, the system according to the invention comprises a fixation profile piece made of two parts which are detachable from one another, one side of the profile piece being provided with a slot for receiving the immobilization element therein, and the other side of the profile piece being provided with a fixation element for cooperating in a fixed manner with a base part such as the patient's bed. One part is made of a high-temperature plastic material which is not deformable at the working temperature. Both parts can be connected to one another by coupling members provided for this purpose.

The system according to the invention therefore comprises a fixation system which has two parts, one part being seated on the immobilization element or being able to be attached thereto by the user, the immobilization element being placed over the body part to be immobilized, and the other part being able to be removably attached to the one part on one side and on the other side being able to have different shapes so that a specific shape fits in or on a given base plate.

The fixing system according to the invention therefore makes it possible to fix an immobilization covering layer to base plates of various types. Furthermore, in the case where a low-temperature plastic material is used, the low-temperature plastic covering layer can be placed completely in the heating medium without the user having to hold the mold. The heating medium can be formed, for example, by a water tank or an oven.

Further properties and features of the fixation system according to the invention are defined in the subclaims.

An exemplary embodiment is described below with reference to the attached drawings.

Short description of the characters
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Figures 1 and 2 show a perspective view and a cross section of the fixation system according to the invention, in the coupled state and with the parts separated from each other, respectively.
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Figure 3 is a schematic plan view of a patient to be treated and who is placed on a table with a fixation plate.

Description

The fixing system shown in Figures 1 and 2 comprises a profile piece with two parts 10, 20 which can be detached from each other and are shaped in such a way that they can be pressed into each other so that the two parts 10, 20 can be easily connected and disconnected from each other, while nevertheless ensuring a firm and reliable connection in the connected state (not shown).

This is done in a very satisfactory way by means of the illu-

. stated shape of the respective ends 19, 29 of the two parts 10, 20 is achieved, which allows these parts to be pushed into one another. The holding part 10 has a fixed shape and is bonded to the fixing cover layer 30 by means of a bonding agent 2, such as adhesive, which ensures that the two parts 30, 2 remain bonded to one another during activation.

However, the part 20 can take on different shapes, in each case extending along one side 29 over the holding part 10 and

along the other side 21 into, on or over a fixing plate 40 of a predetermined shape.

On the holding side 11, the holding part 10 has, for example, the shape of a U, which is pushed over the low-temperature plastic cover layer 30 and is connected by adhesive by means of the connecting means 2, which ensures that the low-temperature plastic cover layer remains held during activation. On the holding side, a slot 11 is formed to hold the cover layer 30, whereby the width of the opening 11 can vary depending on the thickness of the cover layer 30. On its underside, the holding part 10 has a protruding rod-shaped part or projection 12 which fits into a corresponding coupling side 22 of the second part 20.

The second part 20 is therefore provided on the coupling side with a groove 22 which fits tightly over the projection 12 of the holding part 10. Preferably, the groove 22 has a constriction 25 which forms a narrowed section 26 of the groove 22. This constriction 25 exerts a holding effect on the projection 12 and enables the holding part 10 to be snapped into the groove.

The opposite side 21 of the engaging part 20 can have different shapes, such that the part 20 fits into different types of fixing plates 40. This side can, for example, have an L-shape 21, which is known per se, so that it fits into the fixing plate 40 of our existing HP system. However, the side can also be straight with three openings so that it fits over small pins on the fixing plate of a conventional system.

The holding part 10 and the engagement part 20 can therefore be quickly connected to one another in a secure but nevertheless releasable manner without the two parts being able to move against one another as soon as they are pushed or snapped into one another,

unless a significant force is exerted on them. This prevents the two parts 10, 20 from accidentally separating from each other during normal use.

This connection between the holding part 10 and the engagement part 20 is possible due to a combination of the precise, matching shape of the projection 12 and the groove 22, their precise dimensions, the intended tolerances and the characteristics, in particular the elastic properties, of the ABS plastic used.

Different ways of attaching a fixing profile piece or a covering layer consisting of a part to the fixing material were investigated and in these tests the user was able to quickly and reliably attach and remove the fixing profile piece, both during manufacture itself and afterwards, thereby being able to use a different fixing profile piece if necessary, regardless of the fact that it fits better in or on a different base plate, for example.

A clamping system is used in which the fixation profile piece was clamped around the fixation material or cover layer and could be easily removed from it. A system was also tried that had a hook and loop strap that allowed the fixation profile piece and cover layer to be easily connected and disconnected. However, both systems were unable to provide sufficient holding power, with the result that there was a risk that the fixation or cover layer would come loose during activation.

A system was then tried that used screws or press pins to connect the two components together. However, there was the disadvantage that these screws or press pins were large or got in the way of attaching the fixing or cover layer 30 to the base plate 40.

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Finally, tests were carried out in which the high-temperature plastic fixing profile piece was made of two parts 10, 20, with the advantage that these parts can be used on the one hand for different fixing materials for cover layers 30, such as low-temperature plastic, high-temperature plastic and other plastics, and on the other hand can be used on different base plates 40. Consequently, the result is a universal fixing profile piece 1.

According to a further embodiment (not shown), the second part 20 is attached to the first part 10 by means of connecting elements, preferably screws, which also ensures that the two parts 10, 20 can be removed and replaced.

The immobilization element in question is, for example, transparent. However, it can also be opaque.

Figure 3 shows schematically a patient 50 to be treated and who is placed on a fixation plate 40 in which suitable slots 41 are provided at predetermined locations for inserting the engaging side 21 of the part 20 in a well-known manner.

Claims (10)

Expectations 1. Fixation system for an immobilization element for a patient, in particular for a low-temperature immobilization element, with a fastening profile piece (1), one side of which is provided with a slot (11) for receiving the immobilization element (30) therein and the other side of which is provided with a fixing element (21) for cooperating in a fixed manner with a base part (40) as a support for the patient, characterized in that the fastening profile piece (1) has two parts (10, 20) which can be detached from one another and coupled to one another by coupling members (12, 22), the coupling members being provided for this purpose on the two parts (10, 20), one part (10) being made of a high-temperature plastic material which is not deformable at the working temperature. 2. Fixing system according to claim 1, characterized in that the coupling members (12, 22) are formed by a part (12) which protrudes from the one part (10) and an associated groove (22) for receiving the protruding part (12). 3. Fixing system according to claim 2, characterized in that the protruding part (12) can snap into the groove (22). 4. Fixing system according to claim 2 or 3, characterized in that the protruding part (12) can be pressed into the groove (22). 5. Fixing system according to one of claims 2 to 4, characterized in that the projecting part (12) is connected to the one holding part (10) in the region of the bottom zone of the slot (11) · - 12 - and that the groove (22) is provided at a free end of the other part (20) which is arranged opposite the fixing element (21). 6. Fixing system according to one of claims 2 to 5, characterized in that the protruding part (12) is provided at its free end with a bead (13) which is connected to the bottom zone (15) of the one holding part (10) via a ; neck (14) having a smaller cross-sectional dimension than the bead (13). 7. Fixing system according to one of claims 2 to 6, characterized in that the groove (22) is delimited by two side walls (23, 24), of which at least one (23) is elastically deformable with respect to the other (24) in order to receive the protruding part (12) in a dimensionally stable manner in the groove (22). 8. Fixing system according to the preceding claim, characterized in that the two side walls (23, 24) are profiled in such a way that they have projections (25) pointing towards one another at their respective free ends, where they form a narrowed opening (26). 9. Fixing system according to one of the preceding claims, characterized in that the two parts (10, 20) are profiled. 10. Fixing system according to one of the preceding claims, characterized in that the fastening profile piece (1) is made of a low-density plastic material, preferably of a very low-density plastic.