Abstract:
A method and apparatus for safer and more effective deep trans-cervical intra-uterine artificial insemination (AI) is provided. Such a deep AI catheter causes minimal discomfort and risk of trauma, and does not require the services of a highly trained AI professional. First, a catheter is inserted into the cervical tract of the animal. A membrane, initially positioned inside a tube section of the catheter, is then extended from an opening in the tube and into the tract under pressure. The membrane extends into the tract without friction thereby reducing the discomfort and the risk of trauma or injury to the animal. When the membrane is fully extended into the tract, pressure causes the tip of the membrane to open thereby releasing the AI fluid and depositing the genetic material suspended in the fluid into the reproductive tract. In addition to AI and embryo transplant, other applications for the pathway include other therapeutic, diagnostic or procedures, such as introducing fluoroscopic cameras, instruments, and drug delivery.

Description:
PRIORITY AND INCORPORATION BY REFERENCE 
     This application claims priority from a continuation of application Ser. No. 12/045,875, filed on Mar. 11, 2008, now Pat. No. 7,647,891, which is a continuation of application Ser. No. 10/693,660, filed on Oct. 24, 2003, now Pat. No. 7,343,875. This application claims priority from a U.S. Provisional Patent Application No. 60/369,941 entitled “Artificial Insemination Device for Swine”, filed Apr. 3, 2002, which is incorporated by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to the field of creating a pathway into an animal. More particularly, the present invention relates to more effective methods and apparatus for safely creating pathways in mammals for applications such as artificial insemination (AI). 
     In order to feed the world population that is swelling rapidly year after year, there is an urgent need for a safer and more efficient AI of swine and other farm animals, where fresh or frozen semen and/or embryo transfer technology can be used to transfer high genetic value materials, thereby increasing the quality and quantity of the livestock litters.  FIGS. 1A and 1B  show conventional AI catheters for swine. 
     Unfortunately, freezing is usually necessitated by the short life span of fresh genetic materials and the logistics of distribution. Even with advanced freezing techniques, thawing causes a reduction in the mobility, motility and fertility of the spermatozoa, resulting in the need for trans-cervical intra-uterine AI to obtain commercially acceptable conception rates. 
     Referring to  FIGS. 2A ,  2 B and  2 C, a number of attempts have been made to deposit the weakened spermatozoa directly in the uterus or uterine horn by trans-cervical intra-uterine AI using rigid trans-cervical deep insemination catheters. These rigid deep insemination catheters are basically reduced diameter catheters that are enclosed and extend from within a conventional AI catheter. 
     The rigid deep insemination catheters are pushed and/or threaded through cervical canals using bulbous ends or slight angles on their tips in an attempt to navigate the curves and turns of the cervical canal. One inherent flaw of these rigid deep insemination catheters is their hard tips that can easily damage or puncture soft tissue areas during entry and exit procedures, often injuring or even killing the animal. Other disadvantages of these rigid catheters include the need for a professional, such as veterinarian or a highly trained technician, to perform these trans-cervical intra-uterine AI procedures, which reduces but does not substantially eliminate the risk of serious trauma and resulting sterility or death. 
     Hence there is a need for a safer and more effective deep trans-cervical intra-uterine AI catheter that causes minimal discomfort and risk of trauma, and does not require the services of a highly trained AI professional. Such a safer and easier-to-use AI catheter will be especially beneficial to the small farmers in third world countries who cannot afford the services of a professional. 
     SUMMARY OF THE INVENTION 
     To achieve the foregoing and in accordance with the present invention, a method and apparatus for safer and more effective deep trans-cervical intra-uterine artificial insemination (AI) is provided. Such a deep AI catheter causes minimal discomfort and risk of trauma, and does not require the services of a highly trained AI professional 
     In one embodiment, a catheter is inserted into the cervical tract of the animal to begin creating a pathway in the reproductive tract of an animal. A membrane, initially positioned inside a tube section of the catheter, is extended from an opening in the tube and into the tract under pressure. The membrane extends into the tract without friction, i.e. without sliding action between the membrane and the tract, thereby reducing the discomfort and the risk of trauma or injury to the animal. When the membrane is fully extended into the tract, pressure causes the tip of the membrane to open thereby releasing the AI fluid and depositing the genetic material suspended in the fluid into the reproductive tract. 
     In addition to AI and embryo transplant, other applications for the pathway include other therapeutic, diagnostic or procedures, such as introducing fluoroscopic cameras, instruments, and drug delivery. Note that the various features of the present invention, including the extending membrane and the nozzle, can be practiced alone or in combination. These and other features of the present invention will be described in more detail below in the detailed description of the invention and in conjunction with the following figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings and in which like reference numerals refer to similar elements and in which: 
         FIGS. 1A and 1B  are exemplary conventional AI catheters. 
         FIGS. 2A ,  2 B and  2 C show deep rigid deep insemination catheters extending from conventional AI catheters. 
         FIGS. 3A and 3B  are schematic views of the before and after deployment, respectively, of one embodiment of the catheter in accordance with the present invention. 
         FIGS. 4A through 4F  show the assembly of the embodiment of the catheter of  FIGS. 3A and 3B . 
         FIGS. 5A ,  5 B and  5 C show one embodiment of the catheter attached to two exemplary AI dispensers. 
         FIGS. 5D and 5E  show the catheter during and after deployment. 
         FIG. 6  is an enlarged drawing of one embodiment of a tapered nozzle for the catheter. 
         FIGS. 7A through 7E  show the insertion and deployment of the catheter in a sow. 
         FIGS. 8A ,  8 B and  8 C are cross-sectional views of alternative embodiments of the membrane for the catheter. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention will now be described in detail with reference to a few preferred embodiments thereof as illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps and/or structures have not been described in detail in order to not unnecessarily obscure the present invention. 
     In accordance with the present invention,  FIGS. 3A and 3B  are views of one embodiment of catheter  300 , prior to and after deployment of a membrane.  FIGS. 4A through 4F  illustrate the assembly of catheter  300  of  FIGS. 3A and 3B . 
       FIGS. 4A ,  4 B and  4 C show a membrane  410 , a catheter tube  420 , and a subassembly  430  comprising membrane  410  and tube  420 . Membrane  410  can be attached to catheter tube  420  by inserting tip  418  of membrane  410  into opening  421  of tube  420 , until deployable sections  414  and  416  of membrane of  410  are inside hollow  424  of tube  420 . Next, a leading edge  412  of membrane  410  is snapped into a position ring  422  located on the outer surface of catheter tube  420 , as shown in  FIG. 4C . Positioning ring  422  can be machined or molded depending on the manufacturing process. Other chemical and/or physical means of attaching membrane  410  to tube  420  can also be used, e.g., adhesive, heat bonding, ultrasonic welding, chemical bonding or heat staking. 
     As shown in  FIGS. 4D ,  4 E and  4 F, subassembly  430  can be press fitted into catheter nozzle  440 , by engaging membrane edge  412  of subassembly  430  into an internal positioning ring  442  of nozzle  440 . Although subassembly  430  can be sufficiently mechanically coupled to nozzle  440 , the various components of assembled catheter  300  can be further secured to each other by sonically welded or heat staked to prevent separation during deployment, such as inside the reproductive tract during artificial insemination (AI). 
     Alternatively, subassembly  430  can be replaced by a one-piece membrane-tube combination that can be manufactured by, for example, blow molding. Another method for constructing subassembly  430  is to insert catheter tube  420  over a membrane die, similar to dies used in balloon manufacturing, dipping the die and the attached catheter tube  420  into a suitable liquid membrane media until the entire die and about half inch of the end of catheter tube  420  is coated with the membrane media. After the liquid membrane media is cured, membrane tip  418  is cut. A downward movement of catheter tube  420  detaches tube  420  from the die and also automatically inverts membrane  410  into catheter tube  420 , thereby forming subassembly  430 . 
     Membrane tip  418  can include an opening such as a slit or a circular or oval hole. Alternatively, instead of an opening, tip  418  can include a soluble plug or a pre-weakened seal designed to dissolve or fail under pressure at the right time. 
     Depending on the specific application, nozzle  440  can be of different shapes and sizes, and combination thereof, including but not limited to spirals, bulbous knobs, including the nozzles illustrated by  FIGS. 1A ,  1 B,  2 A,  2 B, and  2 C. Although spirals are optional, approximately one to three spirals may be optimal when catheter  300  is used in swine. Shorter nozzles are also possible because membrane  410  is self-sealing, longer and self-guiding. In some embodiments, nozzle  440  is tapered to aid in insertion into the tract. 
     Different membrane materials and size thickness depend on applications and target animal. For virgin sows, also known as gilts, nozzle  440  may have a smaller diameter and shorter length. Conversely, for second to seventh parity sows with larger birth canals, nozzle  440  may have a larger diameter and longer length to facilitate the deposit of genetic materials and/or diagnostic instruments. For example in sows, the overall length of membrane  410  can be approximately four to eight inches and tapering gently from one-eighth of an inch. 
     Depending on the specific type and size of the target application, different materials, size, and thickness can be employed. Suitable materials for nozzle  440  and membrane  410  of catheter  300  include silicone, silicone gel packs, foam, latex, ClearTex™ (available from Zeller International, New York), polymers, plastics, metals, or combinations thereof. Other candidate materials include the polyolefins, polyethylene and polypropylene, the polyacetals, ploy-butadiene-styrene copolymers, the polyfluoro and polyfluorochloro-polymers, such as Teflon™ and other polymers and copolymers. 
     As shown in the cross-sectional views of  FIGS. 8A and 8B , other embodiments include a membrane  810  that are similar to a children&#39;s party noisemaker and an inwardly-rolled embodiment  820  not unlike a condom, respectively. A twin forked-membrane  830  is also possible for deployment into the dual uterine horns of a sow, as shown in  FIG. 8C . 
     Many variations of catheter  300  are possible. For example, catheter  300  may have multiple tubes with multiple membranes. Such an embodiment may be useful in laparoscopy where one pathway is created for a camera and a second pathway is created for an instrument during surgery. Alternatively, a large diameter catheter  300  can also be used to create a large pathway within which one or more smaller catheters can be deployed. 
       FIGS. 5A ,  5 D, and  5 E, show catheter  300 , before, during and after deployment, respectively.  FIGS. 5B and 5C  one embodiment of the catheter attached to two types of AI dispensers.  FIGS. 7A through 7E  show the insertion and deployment of catheter  300  in a sow  780 . Catheter  300  is deployed by introducing genetic material suspended in a suitable fluid under pressure into sow  780 . As shown in  FIGS. 5B and 5C , the AI fluid can be transported in a suitable dispenser, such as a squeeze bottle  560  or a pre-packaged tube  570 . 
     Referring to  FIG. 7A , catheter  300  is inserted into vaginal cavity  782  of sow  780 . Catheter  300  is gradually pushed further into sow  780  until nozzle tip  556  is fully inserted into vagina cavity  782 , as shown in  FIG. 7B . 
     In  FIG. 7C , catheter  300  is then gently eased into cervical tract  784  of sow  780  until nozzle tip  556  engages at least the first cervical ring of cervical tract  784 . Unlike conventional catheters, membrane  410  is not advanced until catheter  300  is positioned in cervical tract  784 , thereby preventing contaminated materials that may be contained in vaginal cavity  782 , or fluids from cervical tract  784 , from being accidentally transferred into uterus  788  or uterine horns of sow  780 . Hence, bio-security of uterus  788  is maintained. 
     Next, as shown in  FIG. 7D , AI fluid under pressure is fed into catheter  300 . Pressure can be generated manually via a dispenser  560  or by a suitable pump, such as a pneumatic or hydraulic pump. The effect of the pressure causes membrane  410  to begin unfolding in an inside-out manner not unlike removing one&#39;s sock by pulling from the open end. Although catheter  300  includes an opening in membrane tip  418 , the AI fluid under pressure keeps the opening of tip  418  closed until membrane  410  is fully extended into cervical tract  784 . 
     Referring now to  FIG. 7E , membrane  410  of catheter  300  continues to advance in a frictionless manner into the curved and narrow passageway of cervical tract  784 , automatically centering the ever-expanding forward most portion of membrane  410  in the direction of least resistance. It is this expansion and automatic centering action of membrane  410  that advantageously enables membrane  410  to worm its way through cervical tract  784  without damaging or irritating delicate tissues. Eventually, when membrane  410  is fully extended and membrane tip  418  is near to or at the entrance of uterus  788 , the pressure causes tip  418  to open thereby allowing the AI fluid to be deposited at the deeper end of cervical tract  786  and/or directly into uterus  788 . 
     While a slight taper of membrane  410  aids deployment in cervical tract  786 , the taper may not be necessary for proper deployment. In some applications, partial penetration of membrane  410  into the uterine horns (not shown) is also possible, allowing for example the introduction of embryo transplants. 
     Hence the invention eliminates the need for multiple removable sheaths by progressively feeding new portion of membrane  410  in an unfolding process. Every newly extended portion of membrane  410  is sterile because there is no prior contact with other biological tissue, such as vaginal cavity or other body fluids. 
     When a suitable amount of AI fluid has been deposited into sow  780 , membrane  410  collapses after the fluid pressure dissipates, allowing for safe and easy withdrawal of the relatively flat, flexible, smooth and lubricated surface of membrane  410 , causing minimal discomfort and posing minimal risk of trauma and damage to the recipient animal. 
     The use of trans-cervical intra-uterine AI advantageously reduces the volume of AI fluid needed for successful insemination by delivering the genetic materials where nature intended, i.e., into uterus  788 . For example, a normal dose of 4-6 billion fresh swine semen may be reduced to fewer than 1 billion for successful AI when trans-cervical intra-uterine AI is employed. 
     In conventional AI, a small window of opportunity for a successful deposit of genetic material suspended in the AI fluid occurs during standing heat, which lasts for only five to eight minutes every one to three hours during estrus, when sow  780  is receptive to boar mounting. During standing heat, when a boar mounts sow  780 , cervical tract  784  clamps onto the boar&#39;s penis to assist ejaculation, and uterine contractions draws the semen through cervical tract  784 . If conventional AI is attempted outside this small window of opportunity, sow  780  will not assist in the drawing of the semen through cervical tract  784 , and much of the AI fluid will backflow out the sow&#39;s vulva and is wasted, thereby reducing the probability of a successful litter. 
     Unlike conventional AI, catheter  300  is effective during refractory heat, which is the much longer period during estrus when cervical tract  784  is relaxed, allowing easier penetration of cervical tract  784 . Since catheter  300  bridges cervical tract  784  and deposits the genetic material suspended in the AI fluid much closer to uterus  788 , resistance caused by clamping cervical tract  784  during standing heat is not needed and probably undesirable. Hence catheter  300  is effective during the much longer refractory heat period because semen can be deposited efficiently and with minimal restriction in cervical tract  784 . 
     Hence the advantages of trans-cervical intra-uterine AI can be combined with the relative safety and effectiveness of catheter  300  of the present invention. Farmers can now use AI in the much longer refractory heat period, allowing these swine farms to operate more efficiently, since successful AI is no longer limited to the much shorter standing heat period. 
     Yet another significant advantage of the present invention is the ability of membrane  410  to deploy in a self-centering and self-directing manner, when deployed under pressure. During manufacture, a suitable lubricant may be applied to the surface of membrane  410  that may come into contact with the tract of the animal, further reducing discomfort and risk of trauma during deployment and withdrawal of catheter  300 . 
     In addition, unlike the conventional rigid deep penetration catheters, once membrane  410  of catheter  300  has been deployed and withdrawn from cervical tract  784 , it is difficult to reinsert membrane  410  back into catheter nozzle  440  and tube  420 , thereby discouraging the reuse of the now contaminated membrane  410 . 
     Once fully extended into a tract of a recipient animal, e.g., into the reproductive tract, respiratory tract, circulatory tract or digestive tract, catheter  300  provides a protective shield for the insertion of devices such as endoscopes, tracheal tubes, or other diagnostic and therapeutic instruments. Membrane  410  shields the tract from the scraping, scarring and discomfort caused by the contact and friction of the hard, semi-blunt instruments and probes on the otherwise unprotected tract. As a result, healing time and the risk of infection are significantly reduced, thereby lowering recovery time and cost. 
     Although the described embodiment of catheter  300  uses an inverted membrane  410  which is turned inside-out during deployment, the concepts of a self-guiding, frictionless, membrane  410  which is deployed with minimal discomfort and trauma to recipient animals has many applications. In addition to AI and embryo transplant, many other applications for catheter  300  are possible. For example, catheter  300  can also be used for diagnostic and/or therapeutic applications in which pathways are created in the reproductive tract, respiratory tract, circulatory tract or digestive tract of the recipient animal or a patient. These pathways enable procedures such as embryo transplant and drug delivery to be performed. Laparoscopic procedures such as introducing cameras and instruments are also possible. Depending on the application, the size and shape of catheter  300  may vary. 
     While this invention has been described in terms of several preferred embodiments, there are alterations, modifications, permutations, and substitute equivalents, which fall within the scope of this invention. It should also be noted that there are many alternative ways of implementing the methods and apparatuses of the present invention. It is therefore intended that the following appended claims be interpreted as including all such alterations, modifications, permutations, and substitute equivalents as fall within the true spirit and scope of the present invention.