Abstract:
An anchor guide for a trocar comprising a tubular body, formed by a plurality of substantially circular sectors, moveable radially toward and away from a longitudinal axis of the tubular body between a first position where they flank one another, according to a first substantially circular arrangement with diameter generally equal to that of the tubular body, and a second position at which they are generally equidistant from one another, according to a second substantially circular arrangement of greater diameter than that of the first arrangement. Each sector is rotatably connected to a support element and a manual operation is provided, moveably connected to the support element, for moving the sectors from the first to the second position and vice versa.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention regards in general the field of equipment for laparoscopic surgery and more in particular refers to a radially expandable anchorage guide for trocars. 
       BACKGROUND ART 
       [0002]    As is known, in the laparoscopic surgery field wide use is made of instruments called trocars which generate and maintain the access channels for the various surgical instruments used in operations. Schematically, a commercial trocar comprises a cannula and a valve body situated at one of its ends. Typically, the cannula has a diameter of 5 or 12 mm with a length of 110-120 mm. 
         [0003]    At the beginning of the operation, some holes are made, for example, in the abdomen of the patient by using as many trocars equipped with an accessory capable of penetrating the various tissue layers. Subsequently, such accessory is extracted and an inert gas is insufflated in the abdomen through one of the trocars so as to generate the necessary operating space. 
         [0004]    The pressure generated inside the abdomen tends to push the trocars outwardly, so that various methods have been devised for their anchorage. The most widespread solution foresees the use of a tube with inner diameter equal to the outer diameter of the trocar cannula and with an outer threaded surface such to permit the surgeon to “screw it” into the access hole. The tube is then fixed to the cannula of the trocar by means of elastic bands or friction systems. 
         [0005]    During the operation, all of the necessary instruments are inserted through the trocars. In the case in which internal parts must be removed, for example gall bladder, intestine parts, tumoral masses etc., it may become necessary to carry out further access cuts of sufficient size for the passage of the part to be removed. This need involves making additional wounds of greater size than those left by the trocars, as well as the possibility of contamination through the walls of the cut during the extraction step of the parts to be removed; all of this results in a more difficult patient recovery after the operation. After the extraction, it is often necessary to continue to operate laparoscopically and the additional cut compromises the gas seal so that it is necessary to use instruments capable of restoring the seal. 
       SUMMARY OF THE INVENTION 
       [0006]    The object of the present invention is to provide an anchorage guide for a trocar which, taking advantage of the elasticity of the relaxed tissues (since they are anesthetized), can expand to generate the necessary space for the extraction of the parts to be removed without the need to carry out additional cuts. 
         [0007]    Another object of the present invention is to provide an anchorage guide for trocars of the type mentioned above on which it is possible to mount an autonomous valve system through which instruments or an adaptor for commercial trocars can pass, if, after the extraction of the diseased parts, it would be necessary to newly pressurize the abdomen and restart the operation. 
         [0008]    These objects are achieved with the anchorage guide for a trocar according to the present invention comprising a tubular body, formed by a plurality of substantially circular sectors, radially moveable from and towards the longitudinal axis of the tubular body between a first position wherein they flank each other according to a first substantially circular arrangement with diameter equal to that of said tubular body, and a second position wherein they are equally spaced from each other according to a second substantially circular arrangement of greater diameter than that of the first arrangement. Each of the sectors is rotatably connected to a support element and manual operation means are foreseen, moveably connected to said support element, for moving the sectors from the first to the second position and vice versa. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    Other characteristics, as well as the advantages, of the anchorage guide for a trocar according to the present invention will be clearer from the following description of an exemplifying and not limiting embodiment with reference to the attached drawings wherein: 
           [0010]      FIG. 1  is a perspective view of the anchorage guide according to the invention in its closed position; 
           [0011]      FIG. 2  is a perspective view of the anchorage guide in its open position; 
           [0012]      FIG. 3  is a cross sectional view of the anchorage guide of  FIG. 1 ; 
           [0013]      FIG. 4  is an exploded view of the anchorage guide according to the invention; 
           [0014]      FIG. 5  is a perspective view of the anchorage guide according to the invention in a completely open position and with a diaphragm valve inserted therein; 
           [0015]      FIG. 6  is a longitudinal sectional view of the anchorage guide of  FIG. 5 ; 
           [0016]      FIG. 7  is a longitudinal sectional view of the anchorage guide according to the invention in its closed position with a commercial valve system; 
           [0017]      FIG. 8  is a perspective view of the anchorage guide according to the invention in is its closed position, equipped with a diaphragm valve with a commercial trocar housed therein; 
           [0018]      FIG. 9  shows a perspective view of the anchorage guide according to the invention with a protective tube. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0019]    With reference to  FIGS. 1-4 , a tubular body, generically indicated with  1 , is formed by three sectors  1   a  of angular width equal to 120°. From one end of each of the sectors  1   a , a curved arm  2  extends in a substantially tangential manner; the free end of the curved arm  2  is rotatably engaged with a pin  3 . The three pins are in turn engaged in three equidistant holes  5  formed on a first ring nut  4 , called fixed ring nut, orthogonal to the longitudinal axis of the tubular body  1  and in circumferential slots  6  made along a second ring nut  7 , called moveable ring nut, coaxially arranged on the fixed ring nut  4 . The threaded ends of the pins  3  projecting from the slots  6  of the moveable ring nut  7  are finally engaged in respective threaded knobs  8 , abutting against moveable ring nut  7  opposedly with respect to the fixed ring nut  4 , thereby obtaining the mutual fixing of the various components. 
         [0020]    The three sectors  1   a  of the tubular body  1  form a channel of inner diameter less than or equal to the outer diameter of the cannula of the commercial trocar to be used, while the outer surface of the sectors  1   a  has a saw tooth thread, as in the anchorage cannulae of known type, capable of grasping the walls of the body cavity access hole. 
         [0021]    The three curved arms  2  are housed within the fixed ring nut  4 , coplanar thereto, and may be simultaneously rotated around the respective pins  3 , to transmit an angular movement to the moveable ring nut  7 . Following the rotation of the arms  2 , the cylindrical sectors  1   a  extending therefrom progressively divaricate from each other, passing from the closed configuration illustrated in  FIG. 1  to the open configuration of  FIG. 2 . 
         [0022]    Three angularly equidistant closure pins  9  and three thrust pins  10  extend orthogonally from the face of the moveable ring nut  7  turned towards the fixed ring nut  4 . When the tubular body  1  is in its closed position, as shown in  FIG. 1 , the closure pins  9  abut on the convex side of the respective curved arms  2  and maintain the three cylindrical sectors  1   a  adjacent to each other, tightening them on the cannula of the trocar so as to permit the axial locking of the trocar. In particular, as shown in  FIG. 4 , the arms  2  have seats  2   a , within which the closure pins  9  are engaged. On the other hand, when the moveable ring nut  7  is rotated in the direction of the arrow F of  FIG. 3 , the thrust pins  10  come into contact with the concave profile of the arms  2  of the sectors  1   a  and, sliding along them away from the hinge pins  3 , ensure that the arms progressively extend. The opening of the sectors  1   a  first occurs quickly and then slows approaching the end stop; in this way it is possible to exert a force as constant as possible throughout the opening step, since the resistance of the tissues increases as the divarication of the sectors  1   a  increases. At the stop end, the tubular body  1  remains stably open when the thrust pins reach the dead point. If it is necessary to stop the opening in an intermediate position, it is sufficient to tighten at least one of the three threaded knobs  8 . 
         [0023]    To ensure an adequate sealing of the gas on the patient side, a membrane  11  is foreseen as shown in  FIG. 4  and  FIG. 7 , while on the surgeon&#39;s side the seal is ensured by a valve system such as that shown in  FIGS. 5 and 7 . The membrane  11  has a variable thickness, and in particular in correspondence with its minimum and maximum diameter terminates with respective toroidal rings  11   a  and  11   b . The maximum diameter ring  11   b  is inserted in a perimetrical groove  4   a  of the ring nut  4 , as is visible in  FIG. 6 , while the minimum diameter ring  11   a  is tight at the base of the sectors  1   a . No groove for housing the ring  11   a  is foreseen on said sectors, since the correct position is maintained both because it is a rest position and because the membrane is forced by the abdomen of the patient against the ring nut  4 . 
         [0024]    The radially expandable anchorage guide for trocars according to the present invention is used in the following manner. At the beginning of the operation, during the insertion step of the trocar in the abdomen (for example), the anchorage guide according to the present invention is used as if it was a normal anchorage tube of the trocar to the abdominal wall. As shown in  FIG. 8 , the three sectors  1   a  are closed around the cannula  12  of the trocar and are tightened to it by rotating the moveable ring nut  7  with respect to the fixed ring nut  4 , and tightening at least one of the locking knobs  8 . In the particular case wherein the trocar inserted is calibrated on the inner size of the closed tubular body  1 , tightening the locking knob  8  can be avoided since the system is irreversible when in completely closed position. A valve  13 , of the type illustrated in  FIGS. 5 and 6 , is closed around the trocar tube to ensure a perfect gas seal. In the case in which the valve is that illustrated in said figures, it is not necessary to tighten the tubular body  1  on the cannula  12  of the trocar, since the same valve can ensure the axial anchorage of the trocar. Indeed, when the membrane tightens around the cannula of the trocar, it generates a consistent radial force which, due to the high coefficient of friction between the same membrane and the cannula of the trocar, ensures a strong axial seal. 
         [0025]    If during the operation it becomes necessary to insert a trocar of greater size, it will suffice to open the valve  13  of  FIG. 8 , open the tubular body  1  by unlocking the cannula  12  of the trocar, extract the trocar to be substituted, insert the new trocar and tighten the tubular body  1  and the seal valve  13  on it. 
         [0026]    If during the operation it becomes necessary to remove an internal mass, the tubular body  1  may be divaricated to its maximum expansion so that, once the trocar and the seal valve is removed, an access channel is generated at the abdomen of sufficient dimensions for the passage of the mass to be removed. 
         [0027]    To protect the walls of the access hole from possible contaminations (for example during the extraction of a tumoral mass in the absence of other types of protection), it is possible to insert within the divaricated sectors  1   a  a tube  14  (see  FIG. 9 ) after having overturned the elastic membrane  14   a  inside the tube itself. In particular, the tube  14  is composed of a rigid cylinder of thin thickness buried within an elastic membrane terminating at both ends with two large diameter discs with reinforced edges, one of which is the membrane  14   a . For its insertion inside the divaricated tubular body  1 , the inner disc or membrane  14   a  is folded inside the tube  14  and subsequently made to expand inside the abdomen. The membrane  14   a  protects from contaminations the inner wall of the abdomen near the access hole. The axial position of the tube  14  is ensured by the tightening of the three sectors  1   a  on it. The tube  14  has an outer elastic disc  15  at the other end which may be folded on the moveable ring nut  7  of the anchorage guide so as to protect it from contamination.  FIG. 9  has the expandable anchorage guide according to the invention in a configuration suitable for the extraction of an internal mass. To extract the tube  14 , it suffices to further divaricate the sectors  1   a  and pull the tube  14  through the outer disc  15 . 
         [0028]    The valve  13  illustrated in  FIGS. 5 and 6  is based on the principal of operation of a commercial device named “LAP-DISC”, described in the U.S. Pat. Nos. 6,110,154 and 6,589,167 and used for making an abdomen access for the surgeon&#39;s hand in hand-assisted laparoscopic surgery operations, even if it uses a different method for maintaining the set position. 
         [0029]    With particular reference to  FIGS. 5 and 6 , the valve  13  comprises a fixed support  16  which can be connected by bayonet coupling to the outer face of the moveable ring nut  7 . On the latter, in fact, radial expansions  17  are foreseen defining circumferential grooves  18  with the outer face of the moveable ring nut  7 , within which radial tongues  19  are friction engaged, extending from the outer wall of the fixed support  16 . The seal between the fixed support  16  and the moveable ring nut  7  is ensured by a seal ring  20  arranged therebetween. The valve  13  moreover comprises a control ring nut  21  rotatably engaged within the fixed support  16  and maintained in the desired angular position by means of flexible arms  22  axially extending from the fixed support  16 . The arms  22  have inner radial projections  23  which are engaged in axial grooves  24  formed on the outer surface of the control ring nut  21 . 
         [0030]    The obturator of the valve  13  comprises an elastic membrane  25  having in rest position a toroidal shape with “omega” cross section, which is maintained tight on the inner walls of the control ring nut  21  and the fixed support  16 , respectively, by means of expansion rings  26  and  27  of rectangular section, cut sideways to permit the flattening of the membrane against the walls of the control ring nut  21  and the fixed support  16  without gap. 
         [0031]    Rotating the control ring nut  21  with respect to the support  16 , the flexible arms  22  bend, making the projections  23  move from one groove  24  to the other, so that the elastic membrane  25 , due to the torsion to which it is subjected, closes radially like a diaphragm. With an appropriate rotation angle of the control ring nut  21 , it is possible to completely occlude the opening of the valve  13 , or partially occlude it in case the cannula of a trocar must pass through said opening, tightening the membrane  25  around it and ensuring the gas seal and a consistent axial tightening. 
         [0032]    The expandable anchorage guide according to the invention, in addition to having the diaphragm valve described above, may naturally be employed even in association with valves for trocars of another type, such as that illustrated in  FIG. 7 . 
         [0033]    The valve herein illustrated is of double seal type: i.e. it has a first elastic obturator  26  with flute mouth geometry which in rest is maintained in closed position by the pressure established in the body cavity. If an instrument is inserted, the flute mouth  26  obturator opens in correspondence with the longitudinal cuts, losing however the gas seal. A second obturator  27  is therefore foreseen, upstream of the first and formed by an elastic membrane with calibrated hole to make a seal on a particular instrument diameter. Normally, having to insert an instrument with different diameter, the second obturator block  27  fixed with bayonet coupling to the first obturator must be substituted. The double obturator scheme as illustrated allows instruments to be extracted and inserted without losing the seal, while, when the instrument is inserted, the second obturator ensures the seal by forcing radially against the instrument. The valve system described and illustrated in  FIG. 7  is among the most commercially widespread, but there exist many others predominantly intended to house instruments with different diameters, without the need to interchange the second obturator. The instrument according to the invention may house, by means of an appropriate adaptor, any commercial sealing system. 
         [0034]    Naturally, the tubular body  1  of the expandable anchorage guide according to the invention can be made in a different number of cylindrical sectors  1   a  with respect to that described and illustrated. In this manner, it is possible to better approximate the circular shape of the realized opening, through the cost of the instrument increases. 
         [0035]    Variations and/or modifications can be made to the anchorage guide for trocars according to the present invention without departing from the protective scope of the invention as set forth in the following claims.