1.  Field of the Invention
The invention relates to sealed packages for securely holding medical devices to prevent their movement within the package.  More particularly, the invention relates to a sterilizable blister package for securely holding one of a variety of sizes of elongated medical devices and releasing the device after the package is opened.  Still more particularly, the invention relates to a package for holding one of a variety of tubular elongated medical devices having various diameters. 
2.  Description of the Prior Art
Sealed blister containers for holding products are commonly used for a variety of products including medical and surgical devices and instruments.  Such containers are generally made by thermoforming, vacuum-forming, injection molding or similarly shaping a polymeric material into a housing having a cavity with the desired shape to contain a particular article.  The containers are particularly useful for holding medical devices because they enable sterilization of the contents and can be made transparent and in a variety of unique shapes. 
The housing is generally formed with at least one open end which is adapted to be sealed with a cover or lid which can be opened without touching (and thereby contaminating) the contents.  The lid is normally heat-sealed to a peripheral flange around the open end of the housing and is generally made from a flexible material such as TYVEK.RTM. ( a registered trademark of Dupont) which is a spun-bonded polyolefin. 
Several design considerations are addressed in developing containers for packaging medical devices in such pre-formed blisters.  First of all, it is often necessary to secure the device from movement within the package.  Such movement may either damage the device, break the seal and compromise the sterility of the device or create undesirable particulate matter within the package which could contaminate the sterile surgical field when the package is opened.  In order to securely hold the device in a given package, the housing cavity is often provided with suitably shaped supporting surfaces to minimize the movement of the device in the cavity.  The function of these surfaces may be supplemented by including within the package a protective device such as a separate compressible insert, for example, polyurethane foam.  Another concern with blister packages for medical devices is that any protective devices within the cavity should remain within the cavity when the lid is opened so the protective devices do not fall into the sterile field during a surgical procedure.  In addition to the foregoing concerns about product movement and loose protective devices, it is desirable to produce a universal-type package which is able to accommodate differently sized products.  This enhances efficiency by minimizing production costs. 
An additional disadvantage of prior art containers is their inability to retain and easily release a product after the lid has been removed.  It would be advantageous to have a package which could be opened and could still retain a device until the user triggers its release without having to touch the device. 
Some prior art devices are known which address some of these design considerations, but not all.  Ignasiak U.S. Pat.  No.  4,324,331, for example, discloses an elongated blister package for containing an elongated surgical implement such as a drill bit, pin or wire.  The package is produced with an elongated cavity having a plurality of longitudinally spaced areas in the cavity for enabling one packaging cavity to be used for various lengths of the implements.  Each of the spaced areas is adapted to receive a separate protective plastic or rubber plug insert at each end of the implement to prevent it from moving and penetrating the ends of the cavity. 
While the Ignasiak patent shows a universal-type of package for receiving a variety of different-length elongated devices, there is no known device which would enable the production of a single package which could receive a variety of different-diameter elongated devices.  Moreover, Ignasiak utilizes undesirable separable inserts. 
Antal U.S. Pat.  No.  5,176,258, assigned to the assignee hereof, discloses a sealed package containing a flexible insert secured to the package lid.  The Antal package is also sized to receive a variety of sizes of products, but includes separable foam inserts which add to package expense and which produce some risk of coming loose. 
Heimann U.S. Pat.  No.  4,216,860 discloses another medical device container in which the protective insert is secured to the lid.  This package has a flexible insert affixed to a backing sheet which is bonded to a peripheral flange and is also adapted to be opened manually--upside down--to dispense the contents onto a sterile field without the need of manual contact.  Removal of the backing sheet pulls the flexible insert out of the package thereby enabling the medical device to fall freely onto a sterile location.  The Heimann package requires separable inserts, is not adapted to a variety of product sizes and does not have a product releasing trigger mechanism. 
It is accordingly an object of this invention to produce a storage container for securely holding relatively rigid elongated medical devices without the need for any component packaging parts other than the container and its lid. 
It is an object of this invention to produce a blister package for receiving a product, in particular a surgical product, wherein the package has an integrally formed structure enabling the retention of the product within the package without any other non-integrally formed devices such as polyurethane foam inserts, etc. 
It is a further object of this invention to produce a two-part blister package for receiving a surgical product, the package parts being a cavity-defining blister having a peripheral flange (i.e. first part) and a cover or lid secured to the flange (i.e. second part) wherein the cavity is capable of receiving and securing a plurality of different diameters of tubular surgical products. 
It is still another object of this invention to produce a blister package having an integrally formed, releasable friction fitting means for securely holding an elongated surgical product and a trigger structure for releasing such product without manually contacting the product. 
It is also an object of this invention to produce a two-part storage container for elongated medical devices having a cutting means at one end of the device, the container capable of isolating the sharp elements of the cutting means from adjacent container walls without requiring any auxiliary inserts or other components. 
It is another object of this invention to produce a package incorporating all of the aforementioned features and made from a material which enables sterilization of the package contents.