Apparatus and method for holding a medical instrument

A method and apparatus are provided for holding a medical instrument. The medical instrument is held in a cradle (112) having first and second interlockable regions (114, 116). The cradle (112) is coupled to a first mating element (124). The first mating element (124) is coupled to a second mating element (126) through a selected aperture (128) of a platform (16), such that the cradle (112) is coupled to the platform (16). The platform (16) has multiple apertures (128, 130, 138).

TECHNICAL FIELD OF THE INVENTION 
This invention relates in general to medical instrument containers and in 
particular to a method and apparatus for holding a medical instrument. 
BACKGROUND OF THE INVENTION 
Since the time Louis Pasteur discovered the germ theory of infection, 
medical instruments have required sterilization to prevent contamination 
and the spread of infection in patients. Hospitals and other medical care 
providers, faced with substantial numbers of instruments to be sterilized, 
continually search for techniques to increase the efficiency and speed of 
sterilization. Moreover, it is difficult for hospitals to accurately 
determine exactly when medical instruments will be used. Accordingly, 
after medical instruments have been sterilized, hospitals require storage 
and transportation facilities to protect the medical instruments against 
physical damage and contamination. 
In order to sterilize medical instruments, hospitals typically use 
sterilizers that apply steam or other sterilizing gases at a specific heat 
and humidity for a predetermined time. These sterilizers kill pathogenic 
organisms located on the instruments and on the containers in which the 
instruments are held. When such containers are removed from the 
sterilizer, the instruments inside the containers are sterile. In order to 
keep the instruments sterile, some previous techniques wrap the 
instruments in cotton muslin fabric or a non-woven polyolefin material. 
The instrument wrap protects the instruments against bacteria, dirt, dust 
and other contaminants so that the instruments are sterile when used. 
Such wraps have several shortcomings. Significantly, wraps neither protect 
delicate instruments from physical damage during handling nor protect 
health care workers from sharp items wrapped inside. Also, wraps require 
extra labor in wrapping the instruments. Further, wraps are susceptible to 
contamination and do not provide for a long shelf-life. Moreover, if wraps 
are made of cotton material, then the wraps must be washed and processed, 
thereby adding extra cost. If wraps are made of non-woven disposable 
materials, then excess waste is created when the wraps are discarded. 
Due to the significant shortcomings of instrument wraps, rigid 
sterilization containers have been developed to hold medical instruments. 
In expediting the sterilization of medical instruments, hospitals prefer 
to vertically stack multiple sterilization containers inside a sterilizer. 
Typically, a rigid tray holds several medical instruments inside the 
sterilization container. Such a tray normally includes an array of 
apertures to allow the passage of gases and condensate. Usually, the tray 
is removable from the rigid sterilization container. 
Many medical instruments are very expensive and require special care during 
physical handling and transportation. If a medical instrument's physical 
size fails to occupy a sufficiently large amount of available space within 
the tray, then movement of the tray can result in collisions between the 
medical instrument and another object such as the tray, the sterilization 
container, or another medical instrument. Collisions might also occur 
between two or more medical instruments if the medical instruments are 
positioned too closely within the tray. 
Such collisions can extensively damage one or more medical instruments in 
the tray. Accordingly, the positioning and organization of medical 
instruments within the tray is especially important for minimizing the 
risks of physical damage to medical instruments during storage, handling 
and transportation of sterilization containers. The relative positioning 
and organization of medical instruments within the tray depends upon each 
instrument's physical design and its freedom of movement within the tray. 
According to some previous techniques for holding medical instruments, 
silicone rubber blocks are custom manufactured into predefined shapes. 
These silicone rubber blocks are inserted into the tray to hold medical 
instruments. Nevertheless, silicone rubber blocks have several 
shortcomings. 
For example, silicone rubber blocks are dedicated to hold only specific 
types of medical instrument sets that have shapes compatible with a 
silicone rubber block's predefined shape. Accordingly, silicone rubber 
blocks impose restrictions that limit their ability to be reconfigured and 
customized by the user to securely hold a variety of different instrument 
sets. Moreover, silicone rubber blocks can be obtrusive, and in many cases 
the area of a medical instrument that contacts a silicone rubber block is 
inadequately sterilized. Further, silicone rubber blocks are frequently 
cost prohibitive. 
According to other previous techniques for holding medical instruments, 
stainless steel is formed into predefined shapes. In one such technique, 
stainless steel is formed into a spring clip and bolted into the tray. A 
medical instrument is snapped into place between two prongs of the 
stainless steel spring clip. In another such technique, stainless steel is 
formed into a rack somewhat analogous in theory to a bicycle rack. Medical 
instruments are parked in respective slots of the stainless steel rack. 
Formed stainless steel has some of the same shortcomings as silicone rubber 
blocks. For example, formed stainless steel is dedicated to hold only 
specific types of medical instrument sets that have shapes compatible with 
the formed stainless steel's predefined shape. Accordingly, formed 
stainless steel imposes restrictions that limit its ability to be 
reconfigured and customized by the user to securely hold a variety of 
different instrument sets. Due to the surface hardness of such steel 
holders, delicate edges on cutting instruments can get nicked and dulled. 
Further, formed stainless steel is frequently cost prohibitive. 
Thus, a need has arisen for a method and apparatus for holding a medical 
instrument, in which an adequate separation is maintained between the 
medical instrument and another object. Also, a need has arisen for a 
method and apparatus for holding a medical instrument, in which efficiency 
is increased. Further, a need has arisen for a method and apparatus for 
holding a medical instrument, in which the risk of physical damage to the 
medical instrument is reduced during storage, transportation and handling. 
Moreover, a need has arisen for a method and apparatus for holding a 
medical instrument, in which a variety of different instrument sets can be 
securely held, and in which an arrangement of instruments can be 
reconfigured and customized by the user if desired. Finally, a need has 
arisen for a method and apparatus for holding a medical instrument, in 
which the medical instrument is securely held in a more cost effective and 
less obtrusive manner, and in which more areas of a medical instrument are 
adequately sterilized. 
SUMMARY OF THE INVENTION 
In a first aspect of a method and apparatus for holding a medical 
instrument, the medical instrument is held in a cradle having first and 
second interlockable regions. The cradle is coupled to a first mating 
element. The first mating element is coupled to a second mating element 
through a selected aperture of a platform, such that the cradle is coupled 
to the platform. The platform has multiple apertures. 
In a second aspect of a method and apparatus for holding a medical 
instrument, the medical instrument is held in a cradle coupled to a first 
distal end of an elongated body. A second distal end of the elongated body 
is coupled to a first mating element. The first mating element is coupled 
to a second mating element through a selected aperture of a platform, such 
that the cradle is coupled to the platform. 
In a third aspect of a method and apparatus for holding a medical 
instrument, at least one medical instrument is held in multiple holding 
devices. 
It is a technical advantage of the present invention that an adequate 
separation is maintained between a medical instrument and another object. 
It is another technical advantage of the present invention that efficiency 
is increased. 
It is a further technical advantage of the present invention that the risk 
of physical damage to a medical instrument is reduced during storage, 
transportation and handling. 
It is yet another technical advantage of the present invention that a 
variety of different instrument sets can be securely held. 
It is yet a further technical advantage of the present invention that an 
arrangement of instruments can be reconfigured and customized. 
In another technical advantage of the present invention, a medical 
instrument is securely held in a less obtrusive manner. 
In a further technical advantage of the present invention, more areas of a 
medical instrument are adequately sterilized. 
It is yet another technical advantage of the present invention that a 
medical instrument is securely held in a more cost effective manner. 
It is an even further technical advantage of the present invention that 
medical instruments can be placed and secured at various levels and planes 
in a tray, thereby increasing the utilization of space and equipment.

DETAILED DESCRIPTION OF THE INVENTION 
The preferred embodiment of the present invention and its advantages are 
best understood by referring to FIGS. 1a through 15 of the drawings, like 
numerals being used for like and corresponding parts of the various 
drawings. 
Referring to FIG. 1a, the present medical instrument sterilization 
container is identified generally by the numeral 10 and may be seen to 
include the housing 12 and the removable lid 14. A removable tray 16 sits 
within the housing 12 and is adapted to receive various medical 
instruments such as scopes, clamps, forceps, scissors and the like. 
An inlet port 18 is disposed on lid 14 in order to allow the passage of 
sterilizing gases such as steam. Inlet port 18 has beneath it a filter 
which allows steam and sterilizing gases to pass through during the 
sterilization process but when dry, prevents or inhibits the passage of 
bacteria and other contaminants into the interior of the container. Inlet 
port 18 is elevated above lid surface 19 so that water or moisture 
generated during the sterilization process is discouraged from entering 
container 10. Two additional filters, to be subsequently described, are 
disposed in the bottom of housing 12. The tray 16 includes removable metal 
handles 20 and 22 to enable easy withdrawal of the tray 16 from the 
housing 12. Apertures 24 are disposed through the tray 16 to allow the 
passage of steam and condensate. Metal clamps 26 are attached on both 
sides of the housing 12 and are manually movable in order to clamp against 
the lid 14 to secure the lid to secure the housing. Suitable sealing 
surfaces are provided between the housing 12 and the lid 14 in order to 
provide an essentially sealed container when the lid is clamped to the 
housing. Handles 28 are provided on opposite ends of container 12 to 
facilitate handling. 
FIG. 1b shows a holding device indicated generally at 110. Holding device 
110 includes a cradle indicated by dashed enclosure 112 for holding a 
medical instrument. Cradle 112 has first and second interlockable regions 
114 and 116. Cradle 112 is connected to a first distal end 118 of an 
elongated body indicated by dashed enclosure 120. A second distal end 122 
of elongated body 120 is connected to a first mating element 124. First 
mating element 124 is selectively coupled to a second mating element 126 
through a selected aperture 128 of tray 16, such that cradle 112 is 
coupled to tray 16. 
Together, first mating element 124 and second mating element 126 form a 
male-female snap where first mating element 124 is the male element and 
second mating element 126 is the female element. Cradle 112 can be 
decoupled from aperture 128 of tray 16 by disconnecting second mating 
element 126 from first mating element 124. Cradle 112 can then be 
recoupled to tray 16 by reconnecting second mating element 126 to first 
mating element 124 through an alternative aperture such as aperture 130. 
Elongated body 120 includes a shaft 132 having an X-shaped cross section, 
as shown in FIG. 1c from the perspective indicated in FIG. 1b. The 
X-shaped cross section of shaft 132 provides structural reinforcement and 
support for holding device 110. Other suitable cross sectional shapes can 
be used in alternative embodiments. Elongated body 120 has a predetermined 
length. In an alternative embodiment, the length of elongated body 120 can 
be adjustably lengthened and shortened to vary a distance between cradle 
112 and tray 16. In the preferred embodiment, holding device 110 can be 
formed of a plastic material such as acetal or delrin. Alternatively, 
holding device 110 can be formed of other materials such as metal or other 
plastics. 
Lateral elements 134 and 136 are coupled through elongated body 120 to 
cradle 112. Lateral elements 134 and 136 are inserted into additional 
apertures 130 and 138 to limit movement of cradle 112, particularly 
rotational movement. Further, lateral elements 134 and 136 stabilize 
cradle 112 to maintain cradle 112 beyond a minimum distance away from tray 
16. Advantageously, even after lateral elements 134 and 136 are inserted 
into additional apertures 130 and 138, additional apertures 130 and 138 
allow passage of gases and condensate through tray 16. Accordingly, 
apertures of tray 16 are only minimally obscured by holding device 110. 
First and second interlockable regions 114 and 116 respectively include 
first and second curved end regions 140 and 142. First and second curved 
end regions 140 and 142 respectively include first and second beads 146 
and 148. Referring to FIG. 1d, first and second interlockable regions 114 
and 116 hold medical instrument 150 by squeezing medical instrument 150 
even if first and second interlockable regions 114 and 116 are unlocked. 
Referring to FIGS. 1e, 1f and 1g, first and second interlockable regions 
114 and 116 are interlocked by hooking first curved end region 140 to 
second curved end region 142, so that holding device 110 holds medical 
instrument 150 by completely circumscribing medical instrument 150. 
Advantageously, medical instrument 150 is more securely held when holding 
device 110 squeezes medical instrument 150 while also completely 
circumscribing medical instrument 150 as shown in FIG. 1g. 
Referring to FIG. 1e, the process of hooking first curved end region 140 to 
second curved end region 142 can be initiated by moving first bead 146 in 
a general direction indicated by arrow 151a and by moving second bead 148 
in an opposite general direction indicated by arrow 151b. After moving 
first and second beads 146 and 148 as shown in FIG. 1e, the hooking 
process continues by moving first and second beads 146 and 148 in the 
general directions indicated in FIG. 1f by arrows 151a and 151b, 
respectively. Finally, the hooking process is completed by moving first 
and second beads 146 and 148 in the general directions indicated in FIG. 
1g by arrows 151a and 151b, respectively. After the hooking process is 
completed as shown in FIG. 1g, first and second beads 146 and 148 
engageably contact to more securely maintain first curved end region 140 
hooked to second curved end region 142. 
As indicated by the changing directions of arrows 151a and 151b between 
FIGS. 1e, 1f and 1g, the process of hooking first curved end region 140 to 
second curved end region 142 essentially involves a twisting motion of 
first and second curved end regions 140 and 142. Advantageously, lateral 
elements 134 and 136 limit rotational movement of shaft 132 during such a 
twisting motion. Moreover, first and second interlockable regions 114 and 
116 of holding device 110 are selectively interlockable, such that medical 
instrument 150 is removable from holding device 110 when first and second 
curved end regions 140 and 142 are unhooked by reversing the twisting 
motion of FIGS. 1e, 1f and 1g. 
The freedom of movement of medical instrument 150 within tray 16 is limited 
by various elements of holding device 110, including interlockable regions 
114 and 116, lateral elements 134 and 136, and mating elements 124 and 126 
(shown in FIG. 1b). Since holding device 110 limits the freedom of 
movement of medical instrument 150 within tray 16, movement of tray 16 is 
less likely to result in collisions between medical instrument 150 and 
another object such as tray 16, sterilization container 10, or another 
medical instrument. Thus, the risk of physical damage to medical 
instrument 150 is reduced during storage, transportation and handling. 
Notably, medical instrument 150 is securely held without requiring a 
physical size of medical instrument 150 to occupy a substantial amount of 
available space within tray 16. Moreover, it is unnecessary for holding 
device 110 to occupy a substantial amount of available space within tray 
16 or to substantially obstruct multiple apertures of tray 16. 
Advantageously, only a slight area of medical instrument 150 is obscured 
by contact with holding device 110. Accordingly, sterilization container 
10 thoroughly and adequately sterilizes medical instrument 150. 
A single holding device 110 can be used to hold an associated medical 
instrument, such as medical instrument 150. Moreover, multiple holding 
devices, such as holding devices 152, 153, 154 and 155 of FIG. 1f, can be 
variously combined for particular applications to securely hold different 
types of medical instruments. For example, elongated bodies 156 and 158 of 
holding devices 152 and 154 have significantly different lengths, such 
that different sections 160 and 162 of medical instrument 164 are held at 
different distances away from tray 16. Moreover, cradles of holding 
devices 152 and 154 have significantly different sizes for holding 
sections 160 and 162 of medical instrument 164 having different sizes. 
Accordingly, medical instruments are securely held in a more cost 
effective manner, because holding devices 152, 153, 154 and 155 can be 
rearranged to securely hold a variety of different instrument sets without 
custom manufacturing. 
Similarly, holding devices 152, 153, 154 and 155 can hold multiple medical 
instruments 164 and 166. The most efficient arrangement of medical 
instruments within tray 16 varies according to the particular combination 
of medical instruments and each instrument's physical design. 
Advantageously, multiple holding devices, such as holding devices 152, 
153, 154 and 155, can be reconfigured and customized to securely hold 
various combinations of dissimilar medical instruments, such as medical 
instruments 164 and 166. 
For example, holding devices 152, 153, 154 and 155 can be decoupled from 
apertures 170a, 170b, 170c and 170d of tray 16 and then recoupled to 
alternative apertures of tray 16 as desired for a particular combination 
of medical instruments. Moreover, cradles of holding devices 152, 153, 154 
and 155 have significantly different sizes for holding medical instruments 
164 and 166 having different sizes. Further, elongated bodies 158 and 172 
of holding devices 154 and 153 have significantly different lengths, such 
that medical instruments 164 and 166 are held at different distances away 
from tray 16. 
By holding medical instruments 164 and 166 at different distances away from 
tray 16, medical instrument 164 can be partially interposed between tray 
16 and medical instrument 166 as shown in FIG. 1f. Since medical 
instrument 164 is partially interposed between tray 16 and medical 
instrument 166, medical instruments 164 and 166 are more closely arranged 
in tray 16. Accordingly, more medical instruments can be securely held in 
tray 16 while being thoroughly and adequately sterilized. Advantageously, 
by securely holding more medical instruments in tray 16, cost efficiency 
and speed of sterilization are increased. 
FIG. 2 illustrates a partially-sectioned view of one embodiment of the 
medical instrument sterilization container shown in FIG. 1a. The inlet 
port 18 may be seen to include apertures 30 which communicate with the 
atmosphere. A removable filter 32 is clamped into place by a twistable cap 
34. A sealing portion 36 is illustrated between the housing 12 and the lid 
14. The clamp 26 may be seen to comprise a stationary portion 38 which is 
pivotally mounted by a pivot 40 to a pivotal clamp portion 42. Manual 
depression upon a lip 44 causes clamp 42 to be moved outwardly in order to 
accept the lid 14. When the lid 14 is in place, the movable clamp member 
42 is moved by spring pressure to clamp against the lid in order to 
sealingly fix it to the housing. 
FIG. 2 further illustrates pedestals 46 which elevate the bottom 45 of the 
housing 12. Also disposed on the bottom of the housing 12 are two outlet 
ports or drains 47 and 49. Contained within each of the outlet ports or 
drains 45 and 49 are disposed filters 48 and 50 which are constructed in a 
manner similar to filter 32 and in the preferred embodiment they are of 
the same construction. Apertures 52 are disposed through the bottom 45 of 
housing 12 in outlet port 47 to permit the passage of sterilizing gases 
and the removal of condensate. The filter 48 is held in position by 
twistable cap 56. A handle 58 is provided on the cap 56 to enable twisting 
into place. Catch members 60 inwardly extend from the bottom of the 
housing 12 for abutting with portions of the cap 56 in order to maintain 
the filter 48 securely in place. 
Notably, the bottom of housing 12 slopes downwardly toward filtered outlet 
ports 47 and 49. Specifically, the bottom walls 62 and 64 each slope 
toward the location of drain 47 in different directions. Thus, condensate 
or moisture in the left-hand side of the tray of the housing 12 will move 
by gravity to the drain 47. Likewise, moisture and condensate in the right 
hand side of the housing 12 will move by gravity along similarly sloping 
housing bottom wall (not shown) to filter drain 49 (not shown). 
Referring again to FIG. 2, tray 16 includes apertures 24 as previously 
noted. Notably, the tray bottom is configured with domes 66 and apertures 
24. This domed configuration causes condensate, steam and the like, to run 
into the apertures 24 and prevent the accumulation of droplets of 
condensate or moisture on the bottom of the tray 16. 
Referring to FIG. 3, which illustrates a section of one corner of a tray 16 
taken along section lines 3--3 in FIG. 2, domed portions 66 shown from a 
top view comprise a rectangle with an aperture 24 located at the corner 
thereof. The domes 66 are formed such that they slope at the corners 
thereof to an aperture 24. Channels 68 are formed between adjacent 
apertures 24 to further assist in draining condensate or moisture through 
the apertures 24. 
FIG. 4 illustrates in greater detail the construction of each of the 
filters 32, 48 and 50 and the manner of securing the filter in the inlet 
and outlet ports. A twistable cap 56 includes four locking flanges 70. The 
filters 32, 48 and 50 are circular in shape and include a plastic member 
71 having plastic cross-members 72 which support the filter media 74. The 
filter media 74 may be any suitable type of commercially available filter 
which allows the passage of sterilizing gases, air and steam therethrough 
but which prevents or inhibits the passage of contaminants such as dirt, 
dust and bacteria. Examples of available filter media include those 
produced and marketed by Dexter. A tab 76 extends from the filter to 
enable manual insertion or removal of the filter. Filters 32, 48 and 50 
are disposable such that they may be periodically replaced. Four locking 
members 60 are formed around the periphery of each port 18, 47 and 49 for 
receiving the filters 32, 48 and 50 and a twistable cap 56. In operation, 
the filters 32, 48 or 50 are placed adjacent to the cover 51 of a selected 
port 18, 47 or 49 and the cap 56 is twisted such that the locking flanges 
70 are tightly held within the locking members 60. 
In the preferred embodiment, the present container is formed from a 
suitable plastic or polymer. As previously noted, clear or translucent 
plastic, has a low thermal conductivity and cannot absorb enough radiant 
heat to eliminate condensate within the housing during the drying cycle of 
the sterilizer system in an economical amount of time. Consequently, the 
preferred embodiment contemplates the use of additional high thermal 
conductivity materials in conjunction with non-filled or clear plastic in 
order to absorb sufficient radiant heat and subsequently rapidly radiate 
that heat through the container to eliminate condensate in an economical 
time frame. The preferred embodiment contemplates the mixture of high 
thermal conductivity materials 78 shown in FIG. 5 within the clear or 
translucent plastic. Alternatively, a coating of high thermal conductivity 
materials can be added to the clear or translucent plastic. It will be 
understood that various types of high thermal conductivity materials may 
be utilized to accomplish the object of the preferred embodiment. The 
following are examples which have been found to work well in practice and 
which provide a sterilization container having a resultant high thermal 
conductivity which tends to elimination of the formation of condensate 
when used in a steam sterilizer. 
EXAMPLE 1 
A plastic is formed for use in a conventional plastic forming machine to 
provide the present container by charging a non-fluxing type high 
intensity mixer with polypropylene copolymer, calcium carbonate and low 
molecular weight polyethylene and mixing to 105 degrees Centigrade. 
Aluminum flakes are then added and mixed for 15-20 seconds. The mixture is 
then fed to a single screw compounding extruder and is melt mixed at a 
temperature of 190 degrees to 205 degrees Centigrade. The resulting 
polymer is then pelletized as it comes out of the extruder. The resulting 
copolymer pellets may be utilized in a conventional forming machine to 
form the present container. The formula for use with this example is 
listed below as a percentage by weight: 
Polypropylene copolymer 55-65% approximately 
Aluminum flake 35-50% approximately 
Low molecular weight polyethylene 1-5% approximately 
Calcium carbonate (CaCO.sub.3) 0-15% approximately 
The polypropylene copolymer may comprise, for example, the copolymer 
manufactured by Eastman Company and noted as Tenite. Aluminum flakes may 
comprise the aluminum flakes manufactured by Transmet Corporation and 
identified as K-151. Suitable low molecular weight polyethylene is 
manufactured by Allied Fibers and Plastics Company as AC-9. A suitable 
source of calcium carbonate is Thompson, Wyman & Company under the trade 
name Atomite. 
EXAMPLE 2 
A non-fluxing type high intensity mixture is charged with polysulfone, EBS, 
CaCO.sub.3 and titanate and is mixed to 150 degrees Centigrade. Aluminum 
flakes are then added and mixed for 15 to 20 seconds. The mixture is then 
fed to a single screw compounding extruder and is melt mixed to a stock 
temperature of 250 degrees to 260 degrees Centigrade. The formula for this 
mixture is listed below as a percentage by weight: 
Polysulfone 50-60% approximately; 
Aluminum flake with silane surface treatment 25-40% approximately; 
(EBS) Ethylenebisstearamide 1-5% approximately; 
Neoalkoxy Titanate 0.01-1% approximately; 
Calcium Carbonate (CaCO.sub.3) 1-15% approximately. 
The polysulfone may comprise, for example, polysulfone manufactured by 
Union Carbide as Udel T-1700. A suitable neoalkoxy titanate is 
manufactured by Kenrich Petrochemicals under the trade name CAPOW 38/M. 
EXAMPLE 3 
A non-fluxing type high intensity mixture is charged with polysulfone, 
titanate and EBS and mixed to 150 degrees Centigrade. Carbon fiber 80 
shown in FIG. 6, is added and the mixture is mixed to 160 degrees 
Centigrade. The mixture is then fed to a single-screw compounding extruder 
and is melt mixed at a stock temperature of 250 degrees to 260 degrees 
Centigrade. 
The formula for this mixture is set forth below as a percentage by weight: 
Polysulfone 90% approximately; 
Carbon fiber 10% approximately; 
Neoalkoxy Titanate 0.01-1% approximately 
(EBS) Ethylenebisstearamide 1-5% approximately 
The carbon fiber may comprise, for example, the fiber manufactured by Union 
Carbide Specialty Polymers and denoted as Thornel (VMD). 
EXAMPLE 4 
A clear or translucent plastic container is formed by one of the mixtures 
noted above such as polypropylene, calcium carbonate and low molecular 
weight polyethylene. A container is formed by conventional forming 
techniques and the interior of the housing and lid is then coated with 
semi-opaque high thermal conductivity material 82 shown in FIG. 7, such as 
a heat resistant paint or the like which contains carbon or the like. The 
container may be coated by painting, dipping or other well-known coating 
techniques. The clear plastic container may alternatively be impregnated 
with carbon pigments under pressure. 
Sterilization containers formed by any of the above examples will have a 
relatively high thermal conductivity. For example, a thermal conductivity 
of polysulfone plastic is approximately 1.7 btu/hr/f.sup.2 /% f/in, while 
the thermal conductivity of aluminum is 10.8 and carbon fiber is 60 
btu/hr/f.sup.2 /0F/in. Plastic containers formed in accordance with the 
preferred embodiment absorb substantially more heat through conduction and 
radiation, and therefore, heat faster and are more effective in moisture 
evaporation as well as more effective in killing bacteria in marginally 
operating steam sterilizers. The present container also enables the heat 
to more rapidly be transmitted to the entire interior, including the tray 
16 thereby more effectively treating moisture or bacteria. 
Referring to FIG. 8, an alternate embodiment of the medical instrument 
sterilization container of the preferred embodiment is shown generally at 
84 and includes housing 12 and a domed removable lid 86. Inlet port 18 is 
disposed at the apex of the domed lid 86. When container 84 is stacked 
with a similar container 84 during the sterilization process, the inlet 
port 18 of the lower container is vertically and laterally spaced from the 
outlet ports 47 and 49 of the upper container such that steam or 
condensate exiting the upper container strikes the domed lid away from 
inlet port 18 of the lower container and is shed to the sides of domed lid 
86. This prevents the steam or condensate from flowing into inlet 18 of 
the lower container of the stack and reduces pooling on the lid surface. 
In the alternate embodiment 84 shown in FIG. 8 and the partially sectioned 
view of FIG. 9, handles 28 are pivotally mounted to the opposite ends of 
housing 12 to provide an improved handhold to facilitate manual transport 
of container 84 while at the same time minimizing space when container 84 
is in storage. In a similar fashion, handles 20 and 22 of removable tray 
16 are pivotally mounted to the sides of the tray to facilitate withdraw 
of the tray 16 from the housing 12. As indicated in FIG. 9, stops 88 are 
provided on the sidewalls of the tray upon which pivotally mounted handles 
20 and 22 rest when not in use. 
Preferably, the area over which apertures 30 are disposed across the apex 
of domed lid 86 is less than the respective areas over which apertures 52 
are disposed across the bottom surfaces of outlet ports 47 and 49. For 
example, apertures 30 through lid 86 may be disposed across an area 
approximately half that of which apertures 52 are disposed across either 
outlet port 47 or outlet port 49. Such a configuration of the apertures 
helps expedite the removal of moisture through outlet ports 47 and 49 when 
a vacuum is applied to the sterilizer chamber by reducing the 
countervailing upward pressure applied through inlet import 18. A more 
complete description of this feature is discussed below, With respect to 
the third embodiment of the present container, which completely eliminates 
inlet port 18 with respect to inlet port 18. 
Referring next to FIGS. 10 and 11, a third alternate embodiment of the 
present sterilization container is shown generally at 90. Sterilization 
container 90 includes an entirely solid domed lid 92 that is in a sealing 
arrangement to housing 12. In contrast to the embodiment previously 
described in connection with FIGS. 1-9, sterilization container 90 is not 
provided with an inlet port 18, hence, no apertures 30 are disposed at the 
apex of lid 92. When a vacuum is applied to the sterilizer chamber to draw 
moisture out of container 90, the problem of countervailing forces through 
an inlet port 32 and the outlet ports 47 and 49 has been eliminated 
completely. 
FIG. 12 depicts a pair of stacked containers 90a and 90b. When stacked, 
ports 47 and 49 of the upper container are vertically offset and laterally 
spaced from the apex of domed lid 92 of the lower container. This stacked 
configuration allows sterilizing steam or gas to flow into and out of 
ports 47 and 49 without impediment while at the same time providing a 
structure in which moisture or condensate exiting ports 47 and 49 of the 
upper container is deflected off the sides of the lid 92 of the lower 
container to the side and reduces possible pooling of moisture. 
FIGS. 13a through 13c depict the use of a pair of stacked containers 90a 
and 90b during the sterilization process in a conventional sterilizer 94. 
In FIG. 13a, steam or sterilizing gas, shown generally by arrows, is 
injected into the chamber of sterilizer 94 through sterilizer inlet 96. 
Initially, the pressure in the sterilizer chamber exceeds the pressure 
inside containers 90a and 90b, providing the requisite pressure 
differential. The steam or gas then enters through ports 47 and 49 across 
the filter barriers provided by filters 48 and 50. Pedestals 46 provide 
the important function of maintaining space between the stacked containers 
such that the steam can enter ports 47 and 49 without substantial 
impediment. The steam flowing into the containers 90a and 90b sterilizes 
the instruments disposed therein. As the steam contacts the instruments 
inside the containers 90a and 90b and the sidewalls of the housings 12 of 
containers 90a and 90b condensate is formed. 
In FIG. 13b, the pressure inside the sterilization containers 90a and 90b 
has equalized with the pressure in the chamber of sterilizer 94. 
Condensate which has formed on the sidewalls of containers 90a and 90b as 
well as the medical instruments disposed therein, drains to the filtered 
ports 47 and 49 along the sloped portions of the bottom housing 12. The 
condensate has a tendency pools on the somewhat hydrophobic barrier 
created by filters 48 and 50 disposed in respective ports 47 and 49. 
Next, as depicted in FIG. 13c, a vacuum is created within the chamber of 
sterilizer 94. The vacuum withdraws the condensate from containers 90a and 
90b by pulling the accumulated condensate across filters 48 and 50 under 
vacuum pressure. The condensate exits the chamber sterilizer 94 through 
outlet 98. The removal of condensate across filters 48 and 50 under vacuum 
pressure allows for a faster and more complete drying of the instruments 
in the container. The elimination of an inlet port 18 through the lid 
eliminates countervailing upward pressure on the condensate which impedes 
rapid withdrawal of the condensate across filters 48 and 50. 
FIGS. 14a and 14b depict alternate approaches to filtering ports 18, 47 and 
49. In the embodiment shown in FIG. 14a, filter media 74 is directly 
inserted into the recess of the respective port 18, 47, 49 and 
subsequently firmly held in place through direct contact with cap 56. A 
cross-sectional view of the filtering approach using filter media 74 
directly inserted into the recess of the respective filter port 18, 47, 49 
is shown in FIG. 15. In FIG. 14b, the filter media is again supported in 
plastic member 71. In this embodiment, however, the filter media 74 is 
supported such that when the filter 32, 48 or 50 is inserted into the 
recess or ports 18, 47, 49, filter media 74 is disposed between the inside 
of the respective container and the cross-members 72. In this 
configuration, the steam or sterilizing gas exiting the container is not 
impeded by the cross-members 72 until it has crossed the barrier provided 
by the filter media 74. This facilitates also more rapid removal of the 
condensate from the container. 
Although the present invention and its advantages have been described in 
detail, it should be understood that various changes, alterations and 
substitutions can be made without departing from the spirit and scope of 
the invention as defined by the appended claims.