Abstract:
A cannulated medical instrument handle apparatus comprises a handle housing component with a hollow handle insert channel and a tubular insert that fits within the handle insert channel. The airspace chamber created between the inner walls of said channel and the outer walls of said insert provides the handle with increased susceptibility to sterilization of the cannula lumen.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/834,338 filed on Jun. 12, 2013. 
     
    
     FIELD OF INVENTION 
       [0002]    This invention relates to the field of medical devices, and more specifically to a cannulated medical instrument handle structurally adapted for high temperature sterilization of inner core elements. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0003]      FIG. 1  illustrates an exploded isometric view of a cannulated medical instrument handle. 
           [0004]      FIG. 2  illustrates a cross-section view of a cannulated medical instrument handle in assembled state. 
           [0005]      FIG. 3  illustrates an exploded isometric cross-section view of a cannulated medical instrument handle. 
           [0006]      FIG. 4  illustrates a cross-section view of a second embodiment of a cannulated medical instrument handle in assembled state 
           [0007]      FIG. 5  illustrates an exploded isometric cross-section view of a second embodiment of a cannulated medical instrument handle. 
       
    
    
     TERMS OF ART 
       [0008]    As used herein, the term “airspace chamber” means the hollow middle section of the handle insert channel with internal diameter D 3  which acts a thermal barrier permitting tubular insert to obtain and retain ambient temperature. 
         [0009]    As used herein, the term “conformed” means structurally configured to conform to geometric dimensions and characteristics. 
         [0010]    As used herein, the term “convex end” means a rounded end component. 
         [0011]    As used herein, the term “distal” means the location situated further from the user. 
         [0012]    As used herein, the term “external diameter D 1 ” means the measurement taken from the top exterior surface of the housing component to the bottom exterior surface of the housing component, taken at any point along the housing. 
         [0013]    As used herein, the term “external diameter D tubext ” means the measurement taken from the top exterior surface of the tubular insert to the bottom exterior surface of the tubular insert, taken at any point along the insert within the tubular shaft segment. 
         [0014]    As used herein, the term “internal diameter D 2 ” means the measurement taken from the top interior surface of the housing component to the bottom interior surface of the housing component, taken at any point along the housing within the distal threaded segment. 
         [0015]    As used herein, the term “internal diameter D 3 ” means the measurement taken from the top interior surface of the housing component to the bottom interior surface of the housing component, taken at any point along the housing within the proximal smooth bore segment. 
         [0016]    As used herein, the term “internal diameter D tubint ” means the measurement taken from the top interior surface of the tubular insert to the bottom interior surface of the tubular insert, taken at any point along the insert within the tubular shaft segment. 
         [0017]    As used herein, the term “length L 3 ” means the length of the interior airspace chamber, which is the measurement taken from the distal edge of the proximal smooth bore segment to the proximal edge of the proximal smooth bore segment. 
         [0018]    As used herein, the term “lumen” means a cannula or hollow shaft that runs through the center of the tubular insert, from the anterior insert aperture to the posterior insert aperture. 
         [0019]    As used herein, the term “proximal” means the location situated nearer to the user. 
         [0020]    As used herein, the term “volume V air ” means the volume of the interior airspace chamber, which is a function of interior diameter D 3 , the external diameter D tubext , and length L 3 , which is the length of the interior airspace chamber. 
         [0021]    As used herein, the term “wall thickness W 3 ” means the measurement taken from the top exterior surface of the housing component to the top interior surface of the housing component, taken at any point along the housing within the proximal smooth bore segment. 
         [0022]    As used herein, the term “wall thickness W tub ” means the measurement taken from the top exterior surface of the tubular insert to the top interior surface of the tubular insert, taken at any point along the insert within the tubular shaft segment. 
       BACKGROUND 
       [0023]    Among hospital patients that have surgery, it is estimated that approximately 2 percent develop a surgical site infection (SSI), and among those who develop an SSI, it is estimated that approximately 3 percent die as a result. It is a problem known in the art that unclean medical instruments are one direct cause of SSIs. Despite scrupulous adherence to cleaning and sterilization standards, which include a multi-step process of rinsing, scrubbing and sterilization, instruments may fail to become sufficiently clean or sterile. 
         [0024]    Cleaning and sterilization of cannulated instruments is particularly challenging. A cannulated medical instrument contains a hollow shaft, known as a lumen, running straight through the center of the instrument, through which a surgeon may introduce, position, manipulate and/or remove surgical and biological material directly to or from the surgical site inside the patient&#39;s body. Operating through the center of a medical instrument allows a surgeon to operate with great precision and through a smaller incision, creating the potential for reduced trauma and a better surgical outcome. However, it is a problem known in the art that the interior of a narrow lumen can be difficult to clean and sterilize. 
         [0025]    Every surface of a medical instrument must be cleaned and sterilized between uses, including lumen&#39;s interior surface. Rinsing and scrubbing steps in the cleaning process should remove physical debris, but then the entire interior surface of the lumen must reach sterilization temperature in an autoclave in order to effectively kill pathogens and meet sterilization requirements. Changing standards in how instruments are sterilized in an autoclave (e.g., reduced cycle time in the autoclave; increased use of autoclave bins with few access holes to allow superheated steam to directly contact instruments) have made sterilization more difficult to achieve than ever before, and some prior art handles may no longer be able to meet sterilization requirements. 
         [0026]    Autoclave tests of prior art cannulated medical instruments have demonstrated that instruments with narrow interior diameters in the lumen take longer to reach sterilization temperature in the middle of the lumen as compared to instruments with wider interior diameters in the lumen. This may be attributed to the greater volume of the structure surrounding a narrower lumen. An instrument with the same overall exterior dimensions but with a wider lumen has thinner walls around the lumen and thus has less mass to absorb heat and impede the rise in temperature as the instrument is heated to sterilization temperature. 
         [0027]    It is desirable to have a medical instrument which offers the surgical benefits of a cannulated instrument but which is capable of being sterilized and cleaned in a manner that meets sterilization requirements and thus prevents SSIs. 
         [0028]    It is desirable to have a cannulated medical instrument with a wider lumen or internal chamber to increase the effectiveness of sterilization in an autoclave. 
         [0029]    It is further desirable to have a cannulated medical instrument with less mass surrounding the lumen or internal chamber to further increase the effectiveness of sterilization in an autoclave. 
       SUMMARY OF THE INVENTION 
       [0030]    The present invention is a cannulated medical instrument handle apparatus comprised of a handle housing component that is partially enclosed within a conformed outer silicone layer. A tubular insert within the handle housing component creates an airspace chamber between the exterior of the tubular insert and an interior housing channel of the handle housing component. 
         [0031]    The handle housing component has an inner surface and an outer surface, as well as a substantially closed proximal convex end, a distal receiving end, and the interior housing channel that creates the interior airspace chamber. The distal receiving end of the handle housing component has a housing aperture which is adapted to receive a ratcheting mechanism. The interior housing channel is threaded at a distal end. 
         [0032]    The tubular insert has an distal end, a tubular shaft segment having a lumen running through its center, and a proximal end. The distal end is externally threaded to interface with the internally threaded portion of the interior housing channel. 
         [0033]    The tubular insert has a constant external diameter D tubext  and an internal diameter D tubint . The interior housing channel has an internal diameter D 3  and a length L 1 . 
         [0034]    The volume V air  of the airspace chamber is proportional to the difference between the tubular insert diameter D tubext  and the internal housing channel diameter D 3 , as well as the length L 3  of the interior airspace chamber. Internal airspace chamber dimensions D 3  and L 3  are designed to enlarge volume V air  of the airspace chamber so that the handle housing component can efficiently reach a target sterilization temperature within an autoclave. 
       DETAILED DESCRIPTION OF INVENTION 
       [0035]    For the purpose of promoting an understanding of the present invention, references are made in the text to exemplary embodiments of a cannulated medical instrument handle, only some of which are described herein. It should be understood that no limitations on the scope of the invention are intended by describing these exemplary embodiments. One of ordinary skill in the art will readily appreciate that alternate but functionally equivalent components and materials may be used. The inclusion of additional elements may be deemed readily apparent and obvious to one of ordinary skill in the art. Specific elements disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one of ordinary skill in the art to employ the present invention. 
         [0036]    It should be understood that the drawings are not necessarily to scale. Instead, emphasis has been placed upon illustrating the principles of the invention. Like reference numerals in the various drawings refer to identical or nearly identical structural elements. 
         [0037]    Moreover, the terms “substantially” or “approximately” as used herein may be applied to modify any quantitative representation that could permissibly vary without resulting in a change in the basic function to which it is related. 
         [0038]      FIG. 1  illustrates an exploded isometric view of a cannulated medical instrument handle  10  as it appears before assembly. Handle  10  has a distal receiving end  25  and a proximal convex end  26 . A tubular insert  20  is inserted via a housing aperture  12  at proximal convex surface  26 . 
         [0039]    Handle  10  has an outer silicone layer  15 . Said silicone layer substantially covers the exterior of said handle. Said outer silicone layer also forms part of housing aperture  12  at proximal convex surface  26 . 
         [0040]    In the embodiment shown, tubular insert  20  is a single machined piece that has a distal end with distal external threads  24   a  and a proximal segment  18 . 
         [0041]      FIG. 2  illustrates a cross-section view of a cannulated medical instrument handle  10  as it appears fully assembled. In the embodiment shown, tubular insert  20  is a single machined piece that has a distal end  17  with external threads  24   a  and a tubular shaft segment  19 . Said tubular shaft segment  19  has a length equal to that of L 3  and ranging from about 0.500 inches to about 5.500 inches. Said tubular insert  20  is comprised of a heat conducting metal such as a surgical-grade stainless steel, alloys or other metals 
         [0042]    Said tubular insert  20  further has an internal diameter D tubint  ranging from about 0.100 inches to about 0.180 inches, an external diameter D tubext  ranging from about 0.137 inches to about 0.254 inches, and a wall thickness W tub  ranging from about 0.037 inches to about 0.074 inches. Said internal diameter enables the interior lumen of the tubular shaft segment  19  to accommodate the passage of medical devices, such as k-wires. Said wall thickness enables the interior lumen of the tubular shaft segment  19  to efficiently reach sterilization temperature in an autoclave when cannulated medical instrument handle  10  is being cleaned. 
         [0043]    Handle  10  has an inner housing component  16  which is comprised of heat conducting metal such as aluminum, stainless steel, alloys or other metals. Said inner housing component  16  includes handle insert channel  14 , which has several distinct sections or segments: a first segment comprising a distal segment  23   a  that terminates at distal receiving end  25  and a second segment comprising a smooth bore segment  23   b  that terminates at proximal convex surface  26 . Distal segment  23   a  has internal threads  24   b . When tubular insert  20  is inserted into smooth bore  23   a , the two components form an airspace chamber  21 . 
         [0044]    As illustrated in  FIG. 2 , said housing component  16  has an external diameter D 1 , a first internal diameter D 2  at the distal segment  23   a , and a second internal diameter D 3  at the smooth bore  23   b . These values of D 1  and D 3  may be constant or may vary along the length of the respective exterior segment and smooth bore segment. 
         [0045]    Said handle housing component  16  also has a wall thickness W 3  determined by D 1 -D 3 . An appropriate wall thickness enables the interior lumen of the tubular shaft segment  19  to efficiently reach sterilization temperature in an autoclave when cannulated medical instrument handle  10  is being cleaned. 
         [0046]    As further illustrated in the exemplary embodiment in  FIG. 2 , tubular insert  20  has a constant external diameter D tubext  for the entire length of its tubular shaft segment  19 , such that when tubular insert  20  is installed within handle insert channel  14  this provides an interior airspace chamber  21  within handle insert channel  14  that efficiently reaches sterilization temperature in an autoclave when cannulated medical instrument handle  10  is being cleaned. In various embodiments, environments and applications, the sterilization temperature may be 270 degrees Fahrenheit, plus or minus about 10 percent. In various embodiments this temperature is sustained from two to twenty minutes. The sterilization temperature is the measured temperature of the chamber in which the instrument is sterilized. Testing environments and processes may also measure temperature inside the cannula, and these measured temperatures will also be 270 degrees plus or minus about 10 percent. 
         [0047]    The volume of V air  of interior airspace chamber  21  is determined by subtracting the external diameter D tubext  of the tubular insert  20  from the second internal diameter D 3  of inner housing component  16 , and multiplying the resulting value by length L 3  of the smooth bore segment  23   a . This resultant value of V air  may range from about 0.113 in 3  to about 0.432 in 3 . 
         [0048]      FIG. 2  also illustrates the distal end of handle insert channel  14  which contains a receiver  11  having a section of threads  24   b  designed to receive interchangeable medical devices. These devices, such as a ratcheting mechanism, can thereby be attached to medical instrument handles. 
         [0049]      FIG. 3  illustrates an exploded isometric view of a cannulated medical instrument handle  10  as it appears before assembly. Tubular insert  20  is inserted into handle insert channel  14  through round housing aperture  12 . As illustrated in the exemplary embodiment in  FIG. 2 , tubular insert  20  fits into inner housing  16  through round housing aperture  12 . The external threads  24   a  of tubular insert  20  then interface with the internal threads  24   b  of distal segment  23   b.    
         [0050]      FIGS. 4 and 5  illustrate an additional embodiment of a cannulated medical instrument handle  10 . All part numbers found within the  FIGS. 4 and 5  directly correspond to the part numbers from the previous embodiment of  FIGS. 1-3 , save for the airspace chamber, which is numbered  22 . 
         [0051]      FIG. 4  illustrates a cross-section view of an additional embodiment of a cannulated medical instrument handle  10  as it appears fully assembled. In the embodiment shown, airspace chamber  22  is of a significantly increased volume V air , thereby enabling handle  10  to more efficiently reach a target sterilization temperature within an autoclave. 
         [0052]      FIG. 5  illustrates an exploded isometric view of an additional embodiment of a cannulated medical instrument handle  10  as it appears before assembly. As shown in  FIG. 4 , airspace chamber  22  is of a significantly increased volume V air , thereby enabling handle  10  to more efficiently reach a target sterilization temperature within an autoclave.