Abstract:
A vascular occlusion screw ( 100 ) for essentially blood-tight occlusion of a blood vessel, the vascular occlusion screw comprising: a. a basically rigid screw head ( 102 ) for fixing the vascular occlusion screw inside the lumen of the blood vessel, the screw head comprising at least one groove ( 106 ) for attachment with an insertion instrument; and b. a semi-rigid or elastic body ( 104 ), the body having a threaded surface helping to occlude the lumen of the blood vessel.

Description:
BACKGROUND 
       [0001]    The present invention relates to the field of medical devices. In particular, the present invention relates to an implantable device used for occluding blood vessels during surgical procedures. 
         [0002]    Occlusion of blood vessels is required to control blood loss during surgical procedures. One example of such a surgical procedure is the surgical treatment of an abdominal aortic aneurysm. 
         [0003]    Abdominal aortic aneurysms are dilatations of the abdominal aorta that result due to the weakening of the wall of the abdominal aorta. Aneurysms of the abdominal aorta may lead to complications such as the spontaneous rupture of the wall of the abdominal aorta. The risk of spontaneous rupture increases when the transverse size of the aneurysm becomes more than 5 cm. 
         [0004]    The spontaneous rupture of an abdominal aortic aneurysm leads to massive internal bleeding, which can prove to be fatal within minutes. Other problems that may be caused by abdominal aortic aneurysms include emboli to the lower limbs and compression of adjacent structures such as abdominal viscera, arteries, veins, and nerves. 
         [0005]    In order to avoid the risk of spontaneous rupture and other complications associated with abdominal aortic aneurysms, surgical repair of abdominal aortic aneurysms is indicated. 
         [0006]    Surgical treatment of the abdominal aortic aneurysms involves the replacement of the diseased part of the abdominal aorta by a vascular prosthesis. This procedure is conducted either through an open surgical procedure or by laparoscopic surgery. 
         [0007]    During this procedure, the abdominal aorta is clamped above and below the aneurysmal section. The wall of the aneurysm is then incised. Once the wall of the aneurysm is incised, the arteries that originate from the aneurysmal section are exposed and start to bleed profusely. If these vessels are not occluded, excessive loss of blood may occur. Excessive blood loss may lead to complications during and after the surgical procedure. 
         [0008]    Various methods are employed to stop the flow of blood from the exposed blood vessels during the surgical procedure for repairing the abdominal aortic aneurysm. These methods involve the application of external pressure on the bleeding vessels, or the insertion of occluding devices into the lumen of the blood vessels. External pressure may be applied on the blood vessel by a surgeon&#39;s fingers, by ligating the blood vessel by means of a suture, or by the application of occluding devices such as forceps or clips. 
         [0009]    Application of external pressure manually by the surgeon&#39;s or the surgeon&#39;s assistant&#39;s fingers is suitable for temporary occlusion of the bleeding blood vessels. However, it cannot be used for permanent occlusion. Moreover, the application of manual pressure interferes with the operative space and may cause hindrance to effectively carry out the surgical procedure. Another limitation of this technique is that it cannot be employed during a laparoscopic procedure. 
         [0010]    During the ligation of the bleeding blood vessels by a suture, the surgeon identifies the bleeding blood vessel and ties a suture around it, thereby occluding it. However, the application of sutures to blood vessels is sometimes difficult, especially during laparoscopic procedures. Moreover, at times, the application of sutures may not lead to a secure occlusion, since the ligature may slip from the blood vessel. In the case of atherosclerotic blood vessels, the ligature may not completely occlude the lumen of the blood vessel. Another problem with the application of sutures on the atherosclerotic blood vessel wall is that the suture may further damage the blood vessel. A tightly applied suture may break through the wall of the blood vessel and result in bleeding. 
         [0011]    Occluding devices such as forceps or clips, which apply external pressure on blood vessels, are used to occlude bleeding blood vessels. However, application of external pressure by means of forceps and clips interferes with the operative field. Furthermore, these cannot be applied to bleeding vessels located behind the wall of the aneurysm. Moreover, it is difficult to use these devices during a laparoscopic procedure since they interfere with an already crowded operative field. In addition, these devices may not result in complete occlusion of the lumen of the bleeding blood vessels, especially in the case of arteriosclerotic blood vessels. 
         [0012]    U.S. Pat. No. 5,292,332 describes a method and device for percutaneous sealing of arterial puncture sites, wherein a screw-like plug is being sealed in blocking relation with the puncture of the wall of an artery. The screw-like plug comprises screw-like threads or protusions or the like on the outer periphery of a body which, furthermore, comprises wing members which are shaped to embed within the subcutaneous tissue layer above the artery and act to further stabilize the plug within the puncture orifice. The plug is arranged to be delivered to the puncture side by means of a delivery catheter comprising a hollow tubular body and having a push member disposed therein. 
         [0013]    U.S. Pat. No. 5,425,757 describes an aortic surgical procedure wherein a plurality of closure elements or plugs are inserted into respective artery tributaries. The plugs are provided with catch elements such as screw threads or shoulders to fix them within the tributaries. A recess or similar element is provided at a proximal end of the closure elements for receiving the operative head of a screw driver or other tool to facilitate insertion of the closure element into the respective blood vessels. The closure elements are specified as having a longitudinal extending channel for allowing penetration by a hypodermic needle for injecting a medically indicated composition into the vessel. 
         [0014]    In light of the above discussion, there is a need for a further improved implantable device that quickly and effectively occludes a blood vessel during surgical procedures. The device should reduce the amount of blood loss during a surgical procedure. It should be simple in its construction and useful during open surgical procedures as well as, most probably, in laparoscopic surgeries. Moreover, such a device should not interfere with access to the operative field. Further, it should help to safely occlude anatomically hidden vessels. 
       SUMMARY 
       [0015]    An object of the invention is to provide a vascular occlusion screw that is suitable for occluding bleeding vessels during surgical procedures. 
         [0016]    Another object of the present invention is to provide a system suitable for occluding bleeding vessels during laparoscopic surgery. 
         [0017]    Yet another object of the present invention is to provide a system suitable for safely occluding anatomically hidden vessels. 
         [0018]    Yet another object of the present invention is to provide a system suitable for occluding bleeding blood vessels without interfering with the operating field. 
         [0019]    Still another object of the present invention is to provide an insertion instrument to insert the vascular occlusion screw into the lumen of the bleeding vessels. 
         [0020]    In accordance with an exemplary embodiment of the present invention, a vascular occlusion screw and an insertion instrument are provided for occluding bleeding blood vessels. The vascular occlusion screw comprises a screw head and a body. The screw head has a groove, to attach to the insertion instrument. The body has a threaded surface and a pointed tip. The threaded surface helps to occlude the lumen of the bleeding vessel; the pointed tip helps to insert the vascular occlusion screw into the lumen of the bleeding blood vessel. 
         [0021]    In accordance with an exemplary embodiment of the present invention, the insertion instrument comprises a handgrip, a head, a shaft, and a cover. The cover helps to protect the vascular occlusion screw while the vascular inclusion screw is inserted during laparoscopic surgery. 
         [0022]    In accordance with an exemplary embodiment of the present invention, a method is presented for occluding bleeding blood vessels during surgical procedures, using a vascular occlusion screw and an insertion instrument. After attaching the vascular occlusion screw to the insertion instrument, the vascular occlusion screw is driven into the lumen of the bleeding blood vessel by applying force through the insertion instrument. 
         [0023]    The additional objects and advantages of the invention will become apparent to those skilled in the art, by referring to the following detailed description, in conjunction with the figures provided. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]    The various embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, wherein like designations denote like elements, and in which: 
           [0025]      FIG. 1  is a representation of a vascular occlusion screw ( 100 ), in accordance with an embodiment of the present invention. 
           [0026]      FIG. 2  is a representation of an insertion instrument ( 200 ) for inserting the vascular occlusion screw, in accordance with an embodiment of the present invention. 
           [0027]      FIG. 3  is a flowchart of a method for occluding a bleeding blood vessel using the vascular occlusion screw during open surgical procedures, in accordance with an embodiment of the present invention. 
           [0028]      FIG. 4  is a flowchart of a method for occluding a bleeding blood vessel using the vascular occlusion screw during laparoscopic surgery, in accordance with an embodiment of the present invention. 
           [0029]      FIG. 5  is a representation of the completed procedure for occluding a bleeding blood vessel using the vascular occlusion screw, in accordance with an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]    The present invention discloses a Vascular Occlusion Screw System (VOSS) for the occlusion of blood vessels during surgical procedures. In particular, the invention provides a vascular occlusion screw for the occlusion of bleeding spinal and lumbar arteries during a surgical procedure for the repair of an abdominal aortic aneurysm. The vascular occlusion screw has a threaded body that helps in occluding the lumen of the blood vessels securely. The present invention further provides an insertion instrument for inserting the vascular occlusion screw into the lumen of a blood vessel. 
         [0031]      FIG. 1  is a representation of vascular occlusion screw  100 , in accordance with an embodiment of the present invention. Vascular occlusion screw  100  has a screw head  102  and a body  104 . Force is applied to screw head  102 , to fix vascular occlusion screw  100  inside the lumen of a blood vessel. Screw head  102  has a groove  106  on one surface. In accordance with an embodiment of the present invention, groove  106  is a cross groove. Body  104  has a threaded surface  108  and a tip  110 . Preferably, the tip is rounded and may, in particular, include the shape of a hemisphere. In a further preferred embodiment, the diameter of the tip is in the range of 1.5 mm to 1.7 mm. 
         [0032]    In accordance with an embodiment of the present invention, the diameter of screw head  102  is within a range of 3 mm to 6 mm, the preferred diameter being around 4 mm. In accordance with an embodiment of the present invention, the thickness of screw head  102  is within a range of 1 mm to 3 mm, the preferred thickness being 2 mm. In accordance with an embodiment of the present invention, the depth of groove  106  on screw head  102  is within a range of 0.5 mm to 1.5 mm, the preferred depth being around 1 mm. Most preferably, the groove has a cross shape and is adapted to be engaged with a Philips screw driver. 
         [0033]    In accordance with an embodiment of the present invention, the length of body  104  is within a range of 2 mm to 10 mm, the preferred length being around 4 mm. 
         [0034]    In accordance with an embodiment of the present invention, diameter of body  104  tapers from screw head  102  towards tip  110 . Body  104  is attached to screw head  102  at its maximum diameter, and the minimum diameter of body  104  is at tip  110 . In accordance with an embodiment of the present invention, the maximum diameter of body  104  is within a range of 2 mm to 6 mm, more preferably between 3.5 mm and 5.0 mm. 
         [0035]    In accordance with an embodiment of the present invention, the minimum diameter of body is within a range of 0.5 mm to 2 mm, more preferably between 0.8 mm and 1.5 mm. Preferably, the length of the screw is in the range of 3.5 mm to 5.0 mm. 
         [0036]    In accordance with a further preferred embodiment, the body  104  has a sharp thread on its outer surface, the thread being inclined at an angle in the range of 8% to 12% relative to a long axis of the occlusion screw. Further preferred, the thread has a cross-section at least in its outer portion which is convex referring to the moving direction of the screw when being inserted into the blood vessel. Further preferred, the body  104  has a basically linear core the diameter of which is slightly smaller than that of the tip, taken between opposing bottoms of the spiral-shaped groove which forms the thread of the body. 
         [0037]    In accordance with an embodiment of the present invention, vascular occlusion screw  100  is made of an absorbable biocompatible material. In accordance with an embodiment of the present invention, the absorbable biocompatible material is Polydioxanone. In accordance with an embodiment of the present invention, vascular occlusion screw  100  is made of a non-absorbable biocompatible material. In accordance with an embodiment of the present invention, the non-absorbable biocompatible material is Polydioxanone. 
         [0038]    The screw head  2  preferably comprises a first, more rigid portion adjoining the body  102  and a second, less rigid portion adjoining the first portion and comprising the at least one groove. 
         [0039]    Vascular occlusion screw  100  is inserted into the lumen of the blood vessel by means of an instrument such as the Philips Screw Driver (known in the art). However, during laparoscopic surgery, vascular occlusion screw  100  has to be inserted through small incisions in the abdominal wall. In such cases, it becomes extremely important that vascular occlusion screw  100  is securely attached to the instrument used to insert it. 
         [0040]      FIG. 2  is a representation of insertion instrument  200  for inserting vascular occlusion screw  100  during laparoscopic surgery, in accordance with an embodiment of the present invention. Insertion instrument  200  has a handgrip  202 , a head  204 , a shaft  206 , and a cover  208 . Handgrip  202  helps in holding insertion instrument  200 , and in applying force to insertion instrument  200 . Head  204  helps in attaching insertion instrument  200  to groove  106  of screw head  102 , and in transmitting force to screw head  102 . Shaft  206  helps in transmitting force from handgrip  202  to head  204 . Cover  208  can be retracted over shaft  206  to expose head  204 . 
         [0041]    The attachment of vascular occlusion screw  100  to head  204  is especially important in the case of laparoscopic surgery. Cover  208  protects vascular occlusion screw  100  while it is being inserted during laparoscopic surgery. Insertion instrument  200 , with cover  208 , can be inserted into an access port created for laparoscopic surgery in a body cavity. In accordance with an embodiment of the present invention, cover  208  has a valve  210 , which prevents the passage of body fluids from inside a body cavity to the outside during a surgical procedure. In addition, valve  210  prevents the passage of air from outside into a body cavity during a laparoscopic surgery. 
         [0042]    In accordance with an embodiment of the present invention, the length of handgrip  202  is within a range of 100 mm to 160 mm, the preferred length being 100 mm. In accordance with an embodiment of the present invention, the diameter of handgrip  202  is within a range of 30 mm to 50 mm, the preferred diameter being 40 mm. In accordance with an embodiment of the present invention, the length of head  204  is within a range of 10 mm to 30 mm, the preferred length being 20 mm. In accordance with an embodiment of the present invention, the diameter of head  204  is within a range of 3 mm to 7 mm, the preferred diameter being 6 mm. In accordance with an embodiment of the present invention, the length of shaft  206  is within a range of 100 mm to 200 mm, the preferred length being 140 mm. In accordance with an embodiment of the present invention, the diameter of shaft  206  is within a range of 3 mm to 10 mm, the preferred diameter being 5 mm. 
         [0043]    In accordance with an embodiment of the present invention, handgrip  202  is made of aluminum. In accordance with an embodiment of the present invention, head  204  is made of biocompatible material. In accordance with an embodiment of the present invention, the biocompatible material is Titan. In accordance with an embodiment of the present invention, shaft  206  is made of biocompatible material. In accordance with an embodiment of the present invention, the biocompatible material is Titan. 
         [0044]    In accordance with an embodiment of the present invention, cover  208  is made of biocompatible material. In accordance with an embodiment of the present invention, the biocompatible material is Titan. In accordance with an embodiment of the present invention, valve  210  is made of a biocompatible material. In accordance with an embodiment of the present invention, the biocompatible material is silicone. 
         [0045]    Having described vascular occlusion screw  100 , and insertion instrument  200  for fixing vascular occlusion screw  100  inside a blood vessel, a method for occluding a bleeding blood vessel using these is described hereinafter. As an example of occluding a bleeding blood vessel during surgical procedures, a procedure for occluding bleeding blood vessels during a surgery for repair of an abdominal aortic aneurysm is described. The bleeding blood vessels are spinal arteries, lumbar arteries, or inferior mesenteric arteries that originate from the diseased aneurysmal section of the abdominal aorta. 
         [0046]    During surgery for the repair of an abdominal aortic aneurysm, the diseased aneurysmal section of the aorta is excluded from the circulation of blood by applying vascular clamps. These clamps are applied proximal and distal to the diseased section of the aorta. Vascular clamps such as the Fogarty aortic clamp may be used for this purpose. After applying the vascular clamps, the diseased aneurysmal section of the aorta is transected. During this procedure, arteries such as spinal arteries, lumbar arteries, or the inferior mesenteric artery are exposed and they may start bleeding. This bleeding is due to the back flow of blood from these blood vessels because of collateral circulation. Vascular occlusion screw  100  is used to occlude these bleeding vessels. 
         [0047]      FIG. 3  is a flowchart of a method for occluding a bleeding blood vessel, using vascular occlusion screw  100 , during open surgical procedures, in accordance with an embodiment of the present invention. At step  302 , vascular occlusion screw  100  is attached to an insertion instrument such as the Philips Screw Driver for inserting vascular occlusion screw  100 . Vascular occlusion screw  100  is attached to the insertion instrument by fixing the insertion instrument to groove  106 . At step  304 , tip  110  of vascular occlusion screw  100  is placed at the site of the bleeding blood vessel, such as the spinal, lumbar or inferior mesenteric arteries. At step  306 , body  104  of vascular occlusion screw  100  is driven into the lumen of the bleeding blood vessel by applying force through the insertion instrument. Body  104  of vascular occlusion screw  100  occludes the lumen of the bleeding blood vessel and stops back bleeding. 
         [0048]    The bleeding blood vessels lying behind the wall of the transected section of the abdominal aortic aneurysm are also occluded using vascular occlusion screw  100 . Use of vascular occlusion screw  100  results in decreased blood loss by occlusion of bleeding blood vessels without obstructing the filed of operation. Also, anatomically hidden blood vessels are occluded using vascular occlusion screw  100 . 
         [0049]    Vascular screw system  100 , along with insertion instrument  200 , can be used to occlude bleeding blood vessels during laparoscopic surgery for repair of abdominal aortic aneurysms.  FIG. 4  is a flowchart illustrating a method for occluding a bleeding blood vessel, using vascular occlusion screw  100  along with insertion instrument  200 , during laparoscopic surgery for repair of abdominal aortic aneurysms, in accordance with an embodiment of the present invention. At step  402 , vascular occlusion screw  100  is attached to head  204  of insertion instrument  200 . Vascular occlusion screw  100  is attached to insertion instrument  200  by fixing head  204  to groove  106 . At step  404 , cover  208  is protracted to secure vascular occlusion screw  100  to head  204 . At step  406 , insertion instrument  200 , along with attached vascular occlusion screw  100 , is inserted into the abdominal cavity. At step  408 , tip  110  of vascular occlusion screw  100  is placed at the site of a bleeding blood vessel, such as spinal, lumbar or inferior mesenteric arteries. At step  410 , cover  208  is retracted from head  204  and attached to vascular occlusion screw  100 . At step  412 , body  104  is driven into the lumen of the bleeding blood vessel by applying force to handgrip  202 . Body  104 , when in place, occludes the lumen of the bleeding blood vessel and stops the back flow of blood from the blood vessel. 
         [0050]      FIG. 5  is a representation of the completed procedure for occluding a bleeding blood vessel, in accordance with an embodiment of the present invention. Body  104  of vascular occlusion screw  100  is inside the lumen of blood vessel  502  and is occluding the flow of blood. 
         [0051]    While the various embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention as described in the claims.