Abstract:
A method of occluding a vessel, comprises forming an incision through tissue covering the vessel to expose a portion of the vessel and looping a first suture around the vessel such that ends of the first suture extend out of the incision in combination with closing the incision with the ends of the first suture protruding through the closed incision, placing a force distribution element over the incision and tightening the first suture over the force distribution element to form a kink in the vessel.

Description:
BACKGROUND 
   A variety of medical procedures involve temporary restriction or stoppage of blood flow to a target region to, for example, prevent excessive bleeding during a procedure or to necrose the target tissue. This is often done by occluding the artery or arteries supplying the target region. 
   Uterine fibroids have been treated by occluding the supply of blood thereto. However, complex surgical procedures may be required to occlude the targeted vessels, adding to the expense and time required for the treatment. It may also be difficult to achieve a desired degree of occlusion without damaging the targeted vessel(s) or the surrounding tissue. Many current methods are also irreversible or reversible only through complicated and/or painful procedures. 
   SUMMARY OF THE INVENTION 
   In one aspect, the present invention is directed to a method of occluding a vessel, comprising forming an incision through tissue covering the vessel to expose a portion of the vessel and looping a first suture around the vessel such that ends of the first suture extend out of the incision in combination with closing the incision with the ends of the first suture protruding through the closed incision, placing a force distribution element over the incision and tightening the first suture over the force distribution element to form a kink in the vessel. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a diagram showing an initial step of a blood vessel occlusion procedure according to the invention; 
       FIG. 2  is a diagram showing a second step of the blood vessel occlusion according to the invention; 
       FIG. 3  is a diagram showing a step using a suture button of the blood vessel occlusion according to the invention; and 
       FIG. 4  is a side elevation view showing the suture button used in the blood vessel occlusion accordance with the present invention. 
   

   DETAILED DESCRIPTION 
   The present invention may be further understood with reference to the following description and to the appended drawings, wherein like elements are referred to with the same reference numerals. As described above, the present invention relates to devices and methods for reducing or stopping blood flow to target tissue. In particular, the present invention relates to devices and methods for occluding uterine arteries, for example, to treat fibroids. 
   The method and device according to the invention facilitates access to one or more target blood vessels to better ensure that blood flow to the target tissue is reduced to a desired degree or stopped, if desired. Furthermore, the procedure is reversible and injury to the surrounding tissue is minimized as forces applied to those tissues by the occluding sutures are distributed over a larger area. 
   A procedure according to embodiments of the present invention, generally comprises exposing target blood vessels (e.g., target uterine arteries) by incising the vaginal fornix and constricting each of the target arteries (e.g., by tightening a loop of suture therearound) to kink each target artery and cut-off blood flow therethrough. A specially shaped force distribution member is used to spread the force of each suture or other loop over a wide area of the overlying tissue to prevent damage as the suture is tightened therearound. Without the force distribution member the suture may cut through the tissue over time. The force distribution member also provides a platform that gives access to intentionally cut the suture against at such time as the physician wishes to remove the force distribution member and the sutures. 
   As shown in  FIG. 1 , an exemplary procedure involves making two incisions  114  in the vaginal fornix  102  at locations defined approximately by the 3 and 9 o&#39;clock positions as one faces the cervix  100 . Each of the incisions exposes one of the uterine arteries  112 , so that the surgeon is able to manipulate the uterine artery  112  as needed. As would be understood by those skilled in the art, a tenaculum clamp  106  may be used to manipulate the cervix  100  and a conventional retractor  104  and speculum  108  may be used to facilitate positioning the tissue and making the incision  114  by exposing the sides of the vaginal fornix  102 . 
   Once the uterine artery  112  has been exposed, the surgeon forms a loop around the target blood vessel with a suture  110  or other similar material so that both ends  110 ′ of the suture  110  extend out of the incision  114 . In this configuration, the suture  110  enters the incision  114 , loops around the artery  112  and then exits the incision  114 . The suture  110  is cut to a length that leaves a substantial amount of material hanging outside of the incision  114 , so that the two ends  110 ′ can be manipulated to form one or more knots, as necessary to carry out the steps according to the invention. The suture  110  is trimmed so that the length thereof is sufficient to permit the inclusion of additional devices behind the knots, as will be described in greater detail below. 
   After the suture  110  is in position around the target uterine artery  112 , the incision  114  is closed, e.g., using a second suture  124 , as shown in  FIG. 2 . The ends  110 ′ of the suture  110  are left to extend beyond the closed incision  114  through the suture  124 , so that they may be manipulated while a portion of the suture  110  remains looped around the artery  112 , within the now closed incision  114 . This condition is shown clearly in  FIG. 2 , and is repeated for both uterine arteries being treated. 
   In a different embodiment, the suture  110  may be replaced with a different material or device that can be looped around the artery  112  to extend out through the incision  114 . For example, a strip of mesh material or another ribbon-like material may be used instead of a conventional filament-like suture to achieve the same result. The material used may also vary depending on the application. For example, the material for the suture or ribbon may be permanent or bio-absorbable, such as PGA, PDO, poliglecaprone, polydioxanone, panacryl or caprosyn. The use of bio-absorbable material simplifies the procedure as there is no need to remove the suture  110  after its purpose has been accomplished. The flow of blood will be restored as the suture is absorbed into the body. 
   As shown in  FIG. 4 , after the second suture  124  has been closed, the loop of suture  110  is tightened around the uterine artery  112  to kink and occlude it. As shown in  FIGS. 3 and 4 , this embodiment of the present invention also includes a force distribution element to prevent the thin material of the suture  110  from cutting into the tissue of the vaginal fornix  102 . The force distribution element spreads the compressive force from the suture  110  over a larger portion of the surface of the vaginal fornix. More specifically, in this embodiment a button  120  is applied over the second suture  124  to overlie the incision  114  and form a barrier between the tissue of the vaginal fornix  102  and the tightening suture  110 . 
   A first face of the button  120  preferably has a shape closely matching a curvature of the vaginal fornix  102 , so that substantially all of the first face contacts the tissue of the fornix  102 . The peripheral outline of the button  120  is also selected to fit comfortably within the vaginal fornix  102  against the cervix without causing pressure points. For example, the button  120  is preferably generally kidney-shaped. Alternatively, the button  120  may take any other shape that allows it to cover the incision  114  and the second suture line  124 , without causing undue discomfort. The material forming the button  120  may be either permanent or bio-absorbable. For example, polyethylene, polypropylene, polycarbonate, nylon, teflon and ABS may be used to construct the button  120 . 
   Furthermore, the button  120  is preferably formed of a low friction material to reduce resistance to the passing of the suture  110  through the orifices  122 . This facilitates tying and tightening the knot or knots  118 . In embodiments that utilize bio-absorbable materials to form the button  120  and the sutures  110 , no follow up procedure is required to remove these elements. Thus, the required hospitalization time and the overall cost of the procedure may be reduced. As would be understood by those skilled in the art, the composition of the suture  110  and of the button  120  are preferably selected to control the amount of time that the target artery is occluded to achieve a desired therapeutic result. 
   The exemplary button  120  comprises two openings  122  that allow the two ends  110 ′ of the suture  110  to pass though, from the first face facing the fornix  102  to the opposite side of the button  120 . Those skilled in the art will understand that the openings  122  may be either holes as shown or notches in an outer edge of the button  120 . The suture  110  is drawn through the button  120  to press the button up against the fornix  102  and to kink and occlude the artery  112 . Then a knot  118  is tied with the ends  110 ′ to maintain the compressive force around the artery  112 . Additional knots may be tied with the ends  110 ′ and pushed down over the original knot  118  to reinforce the position of the button  120  and prevent loosening of the pressure applied around the uterine artery  112 . 
   The steps described above may then be repeated on the other side of the cervix  102 , to occlude the second uterine artery  112 . As described above, two incisions are made on opposite sides of the vaginal fornix  102 , to provide access to both uterine arteries  112  that have to be occluded to successfully treat uterine fibroids. 
   After the button  120  has been tightened in place with the knot or knots  118 , it is left in place for a desired period of time. For example, depending on the reason for the occlusion and the desired effect on the target tissue, the occlusion may be kept in place for 24 hours or less. At the end of the period, if bio-absorbable materials are not used, the surgeon cuts the suture  110  and removes both the button  120  and the suture  110  from the incision  114 . The procedure is repeated on both uterine arteries  112  to restore normal blood flow therethrough and thus to the uterus. In a typical procedure the process necroses the uterine fibroids and causing them to shrink over the subsequent 3-6 months. This reduces symptoms such as discomfort from the bulk of the fibroids and abnormal bleeding. 
   Although the description of the embodiments of the invention presented above is directed primarily to a procedure to occlude uterine arteries and to cause the necrosis of uterine fibroids, those skilled in the art will recognize that the method and apparatus according to the invention may be used in any application where it is desired to reduce or completely stop fluid flow through a vessel or vessels. 
   The present invention has been described with reference to specific exemplary embodiments. Those skilled in the art will understand that changes may be made in details, particularly in matters of shape, size, material and arrangement of parts. Accordingly, various modifications and changes may be made to the embodiments. The specifications and drawings are, therefore, to be regarded in an illustrative rather than a restrictive sense.