Abstract:
The present invention relates to micro-sewing devices, specifically a micro-sewing device for percutaneous, endoscopic, laparoscopic and minimally invasive surgical procedures for suturing in small areas. The device allows for sewing-off and stitching in either direction, in very tight spaces.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention generally relates to sewing devices and more specifically, to very small sewing devices for micro dimension precision needed in surgical environments. 
       BACKGROUND 
       [0002]    Precision stitching in the last several decades has grown more widely in the medical industry because simply, surgeons sew where they can to remove abnormalities or install continuing smaller medical devices. It is a skill honed and mastered early, used virtually in every procedure they are called upon to perform. Originating from basic fabric sewing, it is not that difficult and with practice relatively safe. However, the trend in surgery of implanting medical devices organ removal and bypass type surgical procedures has grown while device size has shrunk. 
         [0003]    Some medical device manufacturing companies are now offering suturing systems and devices aimed at delivering the tactile control and precision associated with open procedures to minimally invasive surgery. 
         [0004]    Present surgical procedures are challenged for device placement in difficult if not thought to be impossible locations previously and much smaller suturing work spaces. As medical devices grow smaller, components must become stronger to handle the resulting stresses, and surgical techniques and tools must change to meet the challenge of working with yet smaller devices with smaller working spaces. This applies to endoscopic, laporscopic and minimally invasive surgical procedures as well as more traditional medical procedures. 
         [0005]    Some procedures for device implantation have proven inadequate because of weakened attachment and dislodged devices pose ongoing danger. The securing of many medical devices such as stints requires suturing into tissue and onto new and tougher artificial materials, weaves and fabrics. The securing of these potentially dislodged devices is problematic, requiring smaller sewing devices and stronger needles. Smaller devices generally mean weaker needles, and any breakages from weakened sutures or overstressed needles adds to the operation risk. But smaller devices also means less intrusive means of suturing, simplifying the healing, and speeding recovery. 
         [0006]    Where the risk is too high, a particular otherwise helpful medical procedure cannot be used. What is needed is: smaller stitching devices, devices which can suture a running stitch or continuous chain of stitching without tearing the tissue or the compromising the thread. What are needed are stitching devices which give the surgeon more precise thread control. 
       Very Small Tubular Devices 
       [0007]    Catheters and other medical devices require very small tubular shapes to enable deployment in the arteries. Many products like Endovascular stent grafts for abdominal and thoracic aortic aneurysms are made of tubular shaped graft material that is ether hand sewn together or precision sewn by machine like the small arm lock stitch machine as taught by Sew Fine™, in 2002 or on sewing devices like the Endovascular deployment machines used to sew deployment sheaths as taught by Sew Fine™, in 1997 and additional equipment provided in 2006. Medical devices used in procedures to support blood vessels, such as Endovascular stent graft, and devices to keep a vessel open, as in coronary stints, it is often the case that the devices are smaller then can be sewn mechanically because the precision cannot meet the dimensional requirements of the work. 
         [0008]    The evolving requirements of medical devices and other non-medical devices press the envelope for sewing on smaller parts and yet smaller parts. In attaching endovascular devices, it is often the case that a sewn device requires a smaller more protective stitching needle then what is currently available. Heart tissue weaknesses can be strengthened with suture repairs. Also, with new technologies evolving in the coronary and other endovascular devices, it is necessary to sew closer to a stent or device than is currently possible. What is needed are smaller stitching devices, small enough to work around stent devices, yet strong enough not to break during the procedure and with thread strong enough to last after the procedure has been completed. 
         [0009]    What is needed are percutaneous surgeries that can be performed in such a manner as to limit the amount of recovery time required, and leave no visible scars. 
         [0010]    One such surgery is called transgastric surgery, or natural orifice translumenal endosurgery, and involves passing flexible surgical tools and a camera in through the patient&#39;s mouth to reach the abdominal cavity via an incision made in the stomach lining. Once the operation is over, the surgeon draws any removed tissue out through the patient&#39;s mouth and stitches up the hole in the stomach. Surgeons have performed appendectomies through the mouth. 
         [0011]    In many ways, transgastric surgery is a natural extension of keyhole surgery, in which slim surgical tools are inserted into the abdomen via small incisions in the skin, avoiding a large cut in the belly. It has now become routine for procedures such as gall bladder removal. 
         [0012]    Transgastric surgery promises to go one better. Much of the discomfort and recovery time after conventional surgery, even keyhole surgery, is due to the incisions made in the abdominal wall. However, because transgastric surgeons reach the abdominal cavity through the mouth, there is no need for an incision, so patients should be back up on their feet much faster. Although an incision is still made in the stomach lining, this is relatively painless, because the stomach has fewer nerve fibers that register pain than our skin. The reduced pain also makes it possible for the procedure to be carried without. Consequently, elderly or infirm patients who may otherwise not be fit enough to receive a general anesthetic, could be treated in this manner. 
         [0013]    Going in via the esophagus to the stomach may also reduce the risk of post-operative infections with, say, the drug-resistant superbug MRSA, which often lives on the skin. If you don&#39;t have skin incisions then you don&#39;t get MRSA. And while there is a risk of infecting the abdominal cavity with bacteria from the gastrointestinal tract, animal studies suggest that risk is small because stomach acid is cleansing. 
         [0014]    What is needed is surgery that can be made pain-free, convalescence-free and scar-free, whilst reducing the risk of complications and infections. 
         [0015]    Stapling is used to close opened tissue in some procedures. However, staples instead of sutures provide a large form body for the body to attack. Also stapling is not a flexible connector often altering the original, natural attachment and the scar tissue is generally more prevalent as a result of stapling. Also, with suture you have the options of using different types, sizes, and strength of suture. What is needed are more suture options. Thus, what is needed are micro sized suturing devices and procedures which can be used in endoscopic, laparoscopic and minimally invasive surgical procedures. 
       Common Catheterization Procedures 
       [0016]    The most common types of interventional catheterization procedures are those performed to: create septal defects, open stenotic valves, open stenotic vessels, close abnormal vessels, or close certain septal defects. Devices and procedures to do these kinds operations are needed, more efficiently and effectively, with less recovery time, smaller chances of infection, and all around cleaner. 
         [0017]    Atrial septal defect (ASD) is a hole in the wall, septum, between the heart&#39;s two uppermost chambers, the right and left atrium. This hole allows blood to flow in either direction between the left and right atrium. ASDs may cause several problems. First, this creates a condition in which the right side of the heart now contains extra blood, and extra blood also now flows to the lungs. This diversion of blood puts strain on the heart because it has to pump this extra blood to the lungs. In addition, the strain put on the right-sided pumping chamber can lead to a weakening or enlargement of the right side of the heart and eventually heart failure, if left untreated. This enlargement may also cause arrhythmias (irregular heart rhythms) to develop. This extra blood flow to the lungs may damage the arteries to the lungs over time, leading to high blood pressure in these vessels. Also, ASDs in some circumstances can allow blood clots from the body to enter the brain and cause a stroke. Open heart surgery is currently the only option and is done only after all other solutions have failed. What is needed is a small device or procedure to close the hole invasively, so that more drastic, possibly catastrophic, and expensive solutions are not the only option. 
       SUMMARY 
       [0018]    The present invention discloses a micro-sewing device having a rotary stitch mandrel oriented at 90 degrees to a needle. A suture retainer timed to move with the rotary stitch mandrel, so that the mandrel suture is held behind the needle. The mandrel suture forms a triangle through which the needle and needle suture pass. Thus, forming a stitch. 
         [0019]    Another embodiment of the invention includes a suture cast off. The suture cast off aids in stitch formation by removing the suture from the rotary stitch mandrel. 
         [0020]    In an alternate embodiment, the invention includes a suture slide control. The suture slide control adjusts tension on the mandrel suture. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0021]      FIG. 1  is a perspective view of a micro sewing device according to an embodiment of the present invention. 
           [0022]      FIG. 2  is a perspective view of the micro sewing device with the housing removed. 
           [0023]      FIG. 3  is a cut-away perspective view of the interior of the top door assembly of the micro sewing device. 
           [0024]      FIG. 4  is a perspective view of the rotary stitch mandrel and suture retainer. 
           [0025]      FIG. 5  is a series of images showing the movement of the rotary stitch mandrel and the needle, as a stitch is formed. 
           [0026]      FIG. 6  is a top view, with the mandrel cover removed, showing the motion of the suture retainer with respect to the rotary stitch mandrel; located in the lower door. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]    In the preferred embodiment displayed in  FIG. 1 , Left housing  1  and right housing  2  are secured by housing mount screws  11  passing through housing mount screw holes  1   a . The housings  1 ,  2  secure the sewing head to door driver  12  by means of door driver pin  29 . Left housing  1  and right housing  2  each have a pin mount slot  1   b  that allows for the longitudinal motion of door driver pin  29 , when door driver  12  is actuated. Housings  1 ,  2  have relief cuts that allow top door  3  and lower door  4  to pass through when actuated by door driver  12 . Housings  1 ,  2  contain holes to mount door hinge pin  10 . 
         [0028]    As shown in  FIGS. 1 and 2 , door hinge pin  10  passes through holes in top door  3  and lower door  14 , allowing rotational motion around door hinge pin  10  when door driver  12  is actuated. Top door  3  includes top cam track  3   b . Lower door  14  includes lower cam track  14   b . Door driver pin  29  passes through top cam track  3   b , door driver  12 , and lower cam track  14   b.    
         [0029]    The top door assembly will be described with reference to  FIGS. 1 and 3 . Needle  5  is secured to needle holder  4 . Needle  5  may be retained against needle holder  4  by pressure from a screw passing through needle holder  4 . Alternatively, needle  5  may be affixed with a threaded portion or permanently attached by welding or other means. Needle holder  4  is retained by a screw (not shown) that passes through hole  3   d  in top door  3 , needle holder  4  and into needle mount  4   c . Needle holder  4  is attached to top door  3  by an additional screw (not shown) that passes through holes  4   a.    
         [0030]    Needle  5  passes through needle slot  6   b  of foot  6 . Foot  6  is pivotally attached to needle holder  4  by foot mount pin  7 . Spring  8  (not shown) resides between foot  6  and needle holder  4  in spring mount  6   c.    
         [0031]    The lower door assembly will be described with reference to  FIGS. 1 ,  3 , and  4 . Mandrel cover  26  is secured to lower door  14  by screws (not shown) that pass through mandrel cover  26  and lower door  14 . Mandrel cover  26  includes needle slot  26   a  that allows needle  5  to pass through mandrel cover  26  and interface with rotary stitch mandrel  15 . Mandrel tensioner  20  is secured between a pin attached to rotary stitch mandrel  15  and pin  14   f  that is secured to lower door  14 . Mandrel tensioner  20  may be a spring, rubber band or other means of exerting force on rotary stitch mandrel  15 . Suture retainer tensioner  22  is secured to suture retainer  21  and pin  14   g  that is secured to lower door  14 . 
         [0032]    Rotary stitch mandrel  15  is rotationally attached to pin  14   e  that is secured to lower door  14 . Cable  30  is attached to rotary stitch mandrel  15  and resides in track  15   b . Cable  30  passes through housing  1 ,  2  and outside the body, parallel to door driver  12 . Suture retainer  21  is rotationally attached to pin  14   h  that is secured to lower door  14 . The motion of suture retainer  21  is limited based on its geometry and its interaction to the pin attached to rotary stitch mandrel  15 . Left suture slide control  17  and right suture cast off  18  are mounted to lower door  14  by screws  19  and  19   a.    
         [0033]    Needle suture tube  13   a  and lower suture tube  13   b  pass roughly parallel to door driver  12 . Needle suture  24  passes through needle suture tube  13   a  and through needle  5 . Lower suture  31  passes through lower suture tube  13   b  and through rotary stitch mandrel  15 . Sutures  24  and  31  exit outside the body, allowing control of tension on the sutures. 
         [0034]    In use, tension of foot spring  8  separates foot  6  from needle holder  4 . door driver  12  is actuated causing door driver pin  29  to move laterally. As door driver pin  29  moves away from door hinge pin  10 , top door  3  and lower door  14  are moved together. The material to be sewn (tissue) is captured between foot  6  and mandrel cover  26 . This causes clamping and compression of the tissue prior to entry of needle  5 . As a result, there is a reduced thickness of material for needle  5  to pass through. Further, the additional stability of the material results in needle  5  being subjected to less side pressure, reducing the likelihood of breakage. Additionally, the force from foot spring  8  maintains pressure between foot  6  and mandrel cover  26 , while needle  5  is withdrawn. 
         [0035]    After needle  5  passes through the material, it passes through needle slot  26   a  in mandrel cover  26 . As it passes below mandrel cover  26 , needle  5  interfaces with rotary stitch mandrel  15  causing a stitch to begin. Stitch formation is discussed in detail later in the description. 
         [0036]    As door driver pin  29  moves toward door hinge pin  10 , top door  3  and lower door  14  are moved apart. Needle  5  is removed from the material while the force from foot spring  8  maintains pressure on the material between foot  6  and mandrel cover  26 . The pressure also aids in forcing needle  5  from the material, preventing needle  5  from getting stuck in the material. 
         [0037]      FIG. 7  describes stitch formation details. 1. The needle  5  is on the up stroke and forms a loop in the needle suture  24 . The rotary stitch mandrel  15  advances through the needle loop. 2. The needle  5  is on the up stroke and rotary stitch mandrel  15  advances through the needle suture  24 . 3. The needle  5  is at TDP (top dead center) and is ready to be advanced to the next stitch location. 4. The needle  5  is on the down stroke. The needle  5  enters the thread triangle formed by the lower suture  31  being held in the correct spot. 5. Needle  5  is on the down stroke. Needle suture  24  is east off the rotary stitch mandrel  15 . 6. Needle  5  is on the up stroke. Needle suture  24  forms a loop and the rotary stitch mandrel  15  goes through the loop. 7. Needle  5  in on the up stroke. When the needle  5  gets to top dead center the machine can be moved to the next stitch location. 
         [0038]    From  FIGS. 3 and 4 , rotary stitch mandrel  15  is moved by cable  30 . Cable  30  may be actuated externally by a surgical handle or by electronic means, as taught by Intuitive surgical (divenchi machine). Alternatively, cable  30  may be actuated by means of a pulley or other attachment to either door  3 ,  14 ; resulting in movement of cable  30  (and therefore, rotary stitch mandrel  15 ) as doors  3 ,  14  are actuated. Movement of rotary stitch mandrel  15  is timed to coincide with the motion of needle  5 , as described in the suture formation steps above. 
         [0039]    Suture retainer  21  is timed to move with rotary stitch mandrel  15 . In the exemplary embodiment, timing is achieved by the curved shape of suture retainer  21  being driven by a pin attached to rotary stitch mandrel  15 . The timing results in suture retainer  21  coming into contact with lower suture  31 . Lower suture  31  is held behind needle  5  on the down stroke described previously. This results in a consistent suture triangle, allowing needle  5  and upper suture  24  to pass through the triangle. After needle  5  passes through the suture triangle, suture retainer  21  moves and releases lower suture  31 . Lower suture  31  forms a loop around needle  5 . As needle  5  moves on the upstroke, the loop is drawn tight into a completed suture. 
         [0040]    This suture retainer  21  consistently controls the position of lower suture  31  behind needle  5 , on the down stroke. This allows for consistent formation of completed sutures regardless of the direction a new suture takes from a previous suture. e.g. a new suture can be formed to the left or right of a previous suture. 
         [0041]    Left suture slide control  17  controls the feed of lower suture  31  as it passes into and around rotary stitch mandrel  15 . As rotary stitch mandrel  15  arrives at the cast of position described above, lower suture  31  encounters right suture cast off  18 . As rotary mandrel  15  passes right suture cast off  18 , lower suture  31  is removed from rotary mandrel  15 . Right suture cast off  18  Mandrel tension  20  returns rotary stitch mandrel  15  to an at rest position as the tension from cable  30  is released. 
         [0042]    Left suture slide control  17  functions to keep needle suture  24  from traveling when it is in contact with rotary stitch mandrel  15 . Additionally, when rotary stitch mandrel  15  is at the opposite end of its stroke, right suture cast off  18  assists in pushing needle suture  24  off of rotary stitch mandrel  15  and completing a stitch. 
         [0043]    As needle  5  descends through the mandrel cover slot  26   a ., lower suture  31  must be held in a specific position to allow for sewing in all directions. Suture retainer  21  holds lower suture  31  in position for descending needle  5  to start a stitch. Suture retainer tensioner  22  returns suture retainer  21  to an at rest position. As the rotary stitch mandrel  15  moves, it moves suture retainer  21  in a timed motion to coincide with the loop of needle suture  24  passing from needle  5 . 
         [0044]    While the stitch created in the preferred embodiment is a 401 2-thread stitch, it is understood that the invention could be modified to create other stitches without departing from its scope and spirit. 
         [0045]    Although particular embodiments of the invention have been illustrated and described, various changes may be made in the form, construction and arrangement of the parts herein, without sacrificing any of its advantages. It is understood that all matter herein is to be interpreted as illustrative and not in any limiting sense and it is intended to cover in the appended claims such changes and modifications as come within the spirit and scope of the invention.