GB2090141A - Medical sterilisation cases - Google Patents

Abstract

A medical sterilisation case (C) comprises a base portion with a base wall (B) and a cover portion with a cover wall (T), the base wall (B) being provided with openings (O) receiving retaining elements (1) for retaining medical articles (I) to be sterilised in the case. Each element (1) comprises a disc-shaped foot (10), the diameter of which is greater than that of the opening (O), a cylindrical neck (20) and a generally conical spigot portion (30). The neck (20) forms a constriction or waist seated in the opening (O) and the spigot portion (20) has a convex free end surface (36) which merges into the adjoining wall surface (34) of the spigot portion. The lower part of the spigot portion has a greater diameter than the opening (O) whereas the upper part of the spigot portion has approximately the same diameter as or a smaller diameter than that of the opening so that for mounting of the retaining element on the base plate, the spigot portion can be pushed through the opening until the neck (20) detents therein. The axial length of the spigot portion (30) is such as to leave between the lower surface of the cover wall (T) and the uppermost point of the end surface (36) a gap (9) which is smaller than the height (b) of the article (I) retained by the spigot portion. <IMAGE>

Description

SPECIFICATION A case The present invention relates to a case, especially a case for an article or articles to be sterilised.

In medicine, or more accurately in surgery, sterilising cases are used, in which are arranged articles, such as surgical instruments and implants, used in operations. Such a case comprises a metallic base portion with a perforated base plate and a metallic cover portion with a perforated cover wall, so that the case and contents can be sterilised by steam or hot air in an autoclave.

In a known case, the base and cover portions are connected together by a hinge at one side similar to a suitcase and closable at the other side by snap fasteners. In addition, insert base plates, which may be provided with rims in the manner of bowls and on which instruments and/or implants can be arranged, are frequently provided inside the case and arranged one above the other.

The base plate of the base portion and/or the insert base plates are provided with retaining means for preventing or at least limiting lateral displacement of articles housed in the case. The retaining means are formed by sheet metal strips which are fastened by spot welding to the base portion or to an insert and which sub-divide the space above the base plate concerned into compartments.

In general, several articles are housed in the same compartment. However, when for example several bone plates are housed in the same compartment, these can collide and become scratched, which is not of course desired, when the case is carried around. Although, a separate compartment could be provided for each article, this would require considerable space, as a sterilisation case may contain up to 50 articles. A further disadvantage is that the articles housed in the case can fall out of the compartments at the top if the case is, for example, tilted during carriage from a sterilising room to an operating theatre. Moreover, the manufacture and fastening of the sheet metal strips serving as retaining means is relatively expensive, as the strips have to be cut, bent and then fastened by spot welding in different ways in accordance with their desired arrangement.

In US Patent Specification No. 4 043 784 there is disclosed a sterilisation tray with a perforated base plate and side walls surrounding this plate.

U-shaped brackets, which consists of stainless steel and the limb ends of which are plugged into holes in the base plate, are provided as retaining means. The limbs of the brackets are provided in the region of their free ends with laterally projecting lugs which, during plugging of the brackets into the base plate, serve as stops and secure the brackets against downward movement In addition, the limbs of the brackets in the unmounted state are slightly splayed so that they stand under a resilient bias after plugging into the base plate.

The brackets are secured against upwardly directed movement away from the base plate only by the frictional forces arising as a consequence of their resilient deformation. There is therefore an appreciable risk that the brackets may drop out when an instrument, which is retained by the brackets, is removed. Moreover, care must be taken during manipulation of the trays that they are not tilted, as the brackets could otherwise drop out. Since the trays are open at the top, surgical instruments and other articles on the trays could also drop out during tilting.

There is accordingly a need for a case suitable for the reception of articles to be sterilised and incorporating one or more retaining elements which provde good space utilisation, are producible and mountable in simple manner and are firmly secured to the case.

According to the present invention there is provided a case comprising a base portion, a cover portion and at least one retaining element for retaining an article disposed in the case, the or each retaining element comprising a disc-shaped foot and a spigot portion which is connected to the foot by a neck portion and which tapers inwardly in a direction away from the foot, the neck portion forming a waist between the foot and the spigot portion and being so engaged in a respective substantially complementary opening in the base portion as to be substantially secure against axial displacement relative to the base portion.

An embodiment of the present invention will now be more particularly described by way of example with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of part of the base plate of a medical sterilisation case according to the said embodiments, the case having retaining elements fastened to the base plate and retaining a surgical instrument (shown in chain-dotted lines); Fig. 2 is 3 section, to an enlarged scale, along the line 2-2 of Fig. 1, showing one of the retaining elements, part of a cover portion of the case also being shown; and Fig. 3 is a plan view of one of the retaining elements.

Referring now to the drawings, there is shown part of a sterilisation case C for the reception of articles, such as surgical instruments and orthopaedic implants, to be used in medicine, especially surgery, and to be sterilised before use in an operation, the case comprising a base portion and a cover portion which are detachably connectible together. When the base and cover portions are firmly connected together, they form a closed, approximately parallelepipedonal case.

The cover portion of the case comprises a cover wall T which, when the case is closed, extends parallel to a base plate B of the base portion.

Fastened to the base plate B is a plurality of elongate retaining elements 1, which extend perpendicularly from the base plate B towards the cover wall T and serve to secure articles, for example a surgical instrument I indicated in chain dotted lines, arranged in the case C against undue lateral movement parallel to the base plate B.

Each retaining element 1 is formed by a onepiece body of polymeric material which is sterilisable through heating to at least 1 00 C, for example 140 to 1450C. Each retaining element 1 can consist of, for example, the synthetic resin material marketed under the designation DELRIN (Trade Mark) by E. I. du Pont de Nemours and Company.

As is evident from Fig. 2, each retaining element 1 is firmly seated in a round opening 0 in the base plate B. The element comprises a disc shaped foot 10 and an upper spigot portion 30, which are connected together by a cylindrical neck 20, the neck being of a reduced diameter and forming a constriction or waist. The foot 10 is bounded at the bottom by a planar, circular end face 12, laterally by a vertical, cylindrical shell surface 14 adjoining the face 12, and at the top by a horizontal annular surface 16. The maximum dimension of the foot transversely to the axis of the spigot portion, i.e. the diameter of the foot, is greater than the corresponding dimension, i.e.

diameter, of the opening 0, so that the surface 1 6 abuts the undersurface of the plate B and the foot 10 serves as a stop preventing upward movement of the element 1. The verticaly extending neck 20 is bounded by a cylindrical shell surface 22, which fits snugly in the opening 0 and has approximately the same diameter as the opening, the length of the neck being approximately equal to the thickness of the bottom plate B. The element 1 thus sits firmly, or at least axially non-displaceably and non-tiltably, in the opening 0.

The generally frusto-conical spigot portion 30 is connected with the neck 20 by a horizontal annular surface 32 and has a conical wall surface 34, which tapers inwardly in a direction towards its free end and is bounded at its free end by a convex, in particular an approximately hemispherical, and surface 36. The maximum transverse dimension, i.e. the maximum diameter, of the wall surface 34 is thus at the lower end thereof at the point of abutment with the annular surface 32 and is greater than the maximum transverse dimension, i.e. diameter, of the opening 0. The wall surface 34 at its upper end, where it merges into the end surface 36, has either approximately the same diameter as the opening O or, preferably, a somewhat smaller diameter than this. For example, approximately the uppermost third of the spigot portion 30 has a smaller diameter than that of the opening 0.

During assembly, the element 1 is pressed into place by inserting the spigot portion 30 through the opening 0. When the final position of the element is reached, the annular surface 32 lies against the upper surface of the plate B and prevents reverse movement of the element.

Because the upper end surface 36 is rotationally symmetrical about the spigot axis and progressively merges into the wall surface 34, this steady transition and the convex shape of the surface 36 facilitate the introduction of the element 1 into the opening 0.

To fasten the element 1 in the bottom plate B, the element 1 is, as already mentioned, axially pushed into the opening 0, so that the upper end surface 36 and then the wall surface 34 pass through the opening until the surface 32 of the neck 22 is disposed in the opening and the annular surface 16 of the foot 10 abuts against the undersurface of the plate B. During introduction of the element 1 into the opening, the spigot portion 30 is temporarily resiliently deformed a small amount so that the element notches into place when the neck 1 is engaged in the opening.

The axial length of the spigot portion 30 should be sufficient for the gap a between the undersurface of the cover wall T of the case C and the uppermost point of the end face 36 to be smaller than the height b of the instrument I or at least the height of the part of the instrument I retained by the spigot portion. Although the instrument I or other retained article is capable of some lateral and vertical displacement within the limits given by the internal height of the case, it is not possible for it to move freely over the entire length and width of the interior of the case. By mounting several retaining elements 1 to the plate B of the case, it is possible to retain each instrument in a desired position.

The case C and articles retained therein may be sterilised for an operation by being exposed alternately to superheated water vapour or hot air and a vacuum in an autoclave. The sterilisation takes place at a temperature of at least 1 00 C, preferably at least 1400 C. To improve the sterilisation, the base plate B and/or the cover wall T are expediently provided with a number of openings distributed over them. These can be formed to be similar to or different from the opening 0. If the extra openings are similar to the opening 0, it is possible to insert retaining elements 1 in selected openings according to the shape of the articles to be accommodated in the case and to leave other openings free.

The base plate B can, as mentioned, belong to the base portion of the case C, form the actual bottom of this and, for example, be continguous with two walls of the case. The base plate B can, however, be formed by a removable separate intermediate plate inserted horizontally into the case. Such an intermediate plate can be augmented by rims to provide an insert bowl.

As will be appreciated, not only surgical instruments, such as the instrument I, but also other articles, for example implants such as bone plates, needed for an operation and to be sterilised can be retained in the case by means of retaining elements in analogous manner.

Claims (13)

1. A case comprising a base portion, a cover portion and at least one retaining element for retaining an article disposed in the case, the or each retaining element comprising a disc-shaped foot and a spigot portion whichis connected to the foot by a neck portion and which tapers inwardly in a direction away from the foot, the neck portion forming a waist between the foot and the spigot portion and being so engaged in a respective substantially complementary opening in the base portion as to be substantially secure against axial displacement relative to the base portion.

2. A case as claimed in claim 1 , wherein the free end portion of the spigot portion of the or each retaining element is smaller in diameter than the associated opening in the base portion.

3. A case as claimed in either claim 1 or claim 2, wherein the section of the spigot portion of the or each retaining element adjoining the neck portion of that element tapers conically inwardly towards the free end of the spigot.

portion.

4. A case as claimed in any one of the preceding claims, wherein the spigot portion of the or each retaining element is bounded at its free end by a convex surface which progressively merges into an adjoining wall surface of the spigot portion.

5. A case as claimed in any one of the preceding claims, wherein the or each retaining element is of integral construction.

6. A case as claimed in any one of the preceding claims, wherein the foot of the or each retaining element is bounded by a radial end face at a side thereof remote from the neck portion, a radial annular surface at a side thereof adjacent the neck portion, and a cylindrical surface joining the radial end face and radial annular surface.

7. A case as claimed in any one of the preceding claims, wherein the neck portion of the or each retaining element and the associated opening in the base portion are both cylindrical and of substantially the same diameter and axial length.

8. A case as claimed in any one of the preceding claims, wherein the or each retaining element consists of a polymeric material sterilisable by heating.

9. A case as claimed in any one of the preceding claims, wherein the spigot portion of the or each retaining element is so shaped and deformable as to be capable of being pushed, starting from its free end, completely through such an opening.

10. A case as claimed in any one of the preceding claims, wherein the base and cover portions are co-operable to close the case and said at least one retaining element is so arranged that when the case is closed the free end of the spigot portion of the element is spaced from a facing surface portion of the cover portion by an amount smaller than a given thickness of an article to be retained by the element.

11. A case substantially as hereinbefore described with reference to the accompanying drawings.

12. A case as claimed in any one of the preceding claims, wherein the case is a medical sterilisation case adapted to conduct a sterilising medium therethrough.

13. A case as claimed in claim 12 and containing at least one medical article retained by the or at least one such retaining element.