Abstract:
A holding apparatus is provided for a trocar sleeve suitable for fixing the trocar sleeve in different positions relative to the patient. The holding apparatus comprises a base member fixedly positionable with respect to the patient and a retainer for the trocar sleeve. The retainer is connected to be tiltable with respect to the base member by a flexible connecting member. According to the invention, the connecting member has a first flexible operational state and a second rigid operational state and the connecting member can be switched between the first flexible and the second rigid operational state.

Description:
CROSSREFERENCE OF PENDING APPLICATION 
     This application is a continuation of pending international application PCT/EP 00/00309 filed on Jan. 17, 2000 and designating U.S. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to an apparatus for holding a trocar sleeve in different spatial orientations relative to a patient, comprising a base member fixedly positionable relative to the patient and a retainer for the trocar sleeve, where the retainer is connected to be tiltable with respect to the base member by a flexible connecting member. 
     A holding apparatus of this type is disclosed in U.S. Pat. No. 5,540,675. 
     A trocar provides access into the body in minimally invasive surgery. A small incision can be made with a trocar mandrel, through which incision the trocar sleeve is inserted into the body of the patient. The trocar mandrel is subsequently withdrawn from the trocar sleeve. The trocar sleeve thus forms an access channel into the body of the patient. 
     Trocars are used particularly in minimally invasive surgeries in the stomach region, the field of laparoscopy. Its use however is not limited thereto. Medical instruments can be reliably guided and held in the channel formed by the trocar sleeve and, in addition, the channel serves to supply or discharge fluids or gases into or out of the patient&#39;s body. For this purpose, a flap valve housing is usually provided at the proximal end of the trocar sleeve with corresponding sealings and stop cocks. 
     The trocar sleeve is located in a spatial orientation corresponding to the incision channel. The trocar sleeve however can be varied in its orientation by hand; it returns to the direction of the incision channel when the tube is released. This results from the tendancy of the tissue layers penetrated by the trocar to realign themselves to a certain position. For this reason, apparatus of the above-mentioned type are used to hold the trocar sleeve in certain positions. 
     One or more different spatial orientations of the trocar sleeve is desirable during a surgery. In a first operational state, the holding apparatus retaining the trocar sleeve is slightly adjustable. Once the trocar sleeve is oriented in the desired position, it should no longer change its disposition. In a second operational state, the holding apparatus is rigid and the trocar sleeve remains fixed in the selected spatial orientation. 
     The holding apparatus disclosed in mentioned U.S. Pat. No. 5,540,675 comprises an annular base portion which is directly secured to the patient&#39;s body with an adhesive layer. The annular base portion is connected with elastic, rubber connecting members to a retainer arranged centrally with respect to the base portion and in the starting condition perpendicular to it. The retainer in the present case itself is tube-shaped. The trocar sleeve is inserted into the retainer. To orient and to fix the retainer in different directions with respect to the base portion, a telescopic-like tensioning mechanism is provided consisting of at least one tensioning element adjustable in length. It is secured between the radially outward region of the base portion and the end of the retainer lying remote from the base portion. The inclination of the retainer relative to the base portion can be varied by adjusting the length of the tensioning element. However, it is first necessary to release the tensioning element with a screw, to adjust the tensioning element to the desired length and finally to again tighten the screw. In one embodiment of the known holding apparatus, three tensioning elements in the form of a tripod are arranged about the retainer for reasons of stability. The trocar sleeve can only be tilted in one single plane with one tensioning element. The adjustment and securement of the desired position of the retainer is complicated in this known holding apparatus. To change the spatial position of the trocar sleeve, all three tensioning elements for fixing the retainer must first be released, and then adjusted and finally retightened. Should the operator after inserting an instrument, for example an endoscope, find that the orientation is not yet exact, he must again carry out the complicated procedure. Extremely tilted positions of the trocar sleeve are not achievable in a stable manner due to the tripod geometry. 
     Furthermore, the tensioning elements of this known apparatus comprise numerous bacterial niches, cavities and corners, for example the threadings of the adjustable screws and the telescopic shafts, so that the known apparatus is difficult to clean and to sterilize. 
     Another type of apparatus for aligning and fixing medical instruments is described in the U.S. Pat. No. 5,597,146, which is representative for numerous similar arrangements. This type of apparatus comprises a multi-link pivot arm, whose individual link elements can be oriented independent from one another about different axes. A medical instrument to be fixed can be positioned and held at an arbitrary position, similar to a robot arm. This type of apparatus however is very complicated with respect to its construction and manufacture. In addition, it takes up space on the operating table above the patient and thus obstructs the surgeon&#39;s access to the patient from several directions. 
     It is, therefore, object of the present invention to provide an apparatus of the mentioned type, which is simple to operate and enables a rapid and at the same time reliable adjustment and fixation of the spatial orientation of the trocar sleeve relative to a patient. 
     SUMMARY OF THE INVENTION 
     This object is achieved in that the connecting member has a first operational state in which it is flexible and a second operational state in which it is rigid and in that the connecting member is switchable between the first flexible and the second rigid operational state. 
     The apparatus according to the invention does not require telescopic-like or column-like tensioning elements held with screws, whose handling is cumbersome and complicated. The invention instead provides the degree of flexibility or of rigidity of the flexible connecting member to be variable itself. It is therefore possible in a first operational state, where the connecting member is flexible, to align the trocar sleeve and also the medical instrument therein in the desired position. By switching over to the second operational state where the connecting member is rigid, the trocar sleeve is then fixed in the adjusted position. 
     The realization of a connecting member with two such different operational states is technically possible in different ways. Preferred manners of realization are correspondingly described in the following with reference to the dependent claims. 
     The apparatus according to the present invention has the advantage that the adjustment and fixation of the trocar sleeve position and therefore the medical instrument passed therethrough, is easily possible in any, even extreme tilted position in the first flexible operational state, while the adjusted position is safely and reliably held in the second rigid operational state. Compared to the known apparatus, the present apparatus is much easier to operate. At the same time, it is possible to place the present apparatus with its base directly adjacent to the patient to be treated, for example on his abdominal wall. This has the advantage that the apparatus and therefore the trocar sleeve held therein follows changes in the position of the patient. An undesired relative movement of the trocar sleeve with respect to the patient is avoided. Finally, the present apparatus requires very little space, so that access to the patient from different sides is not obstructed. 
     The connecting member comprises an elastic casing filled with a material having variable rigidity. This feature has the advantage that the material can have the properties of a flowable mass in the first operational state, because the material is contained by the elastic casing. With this, a particularly simple adjustment of a given spatial orientation of the trocar sleeve is possible. Furthermore, this feature has the advantage that the apparatus has a uniform and smooth surface, due to the elastic cover, preferably of silicone, which is simple to clean and to sterilize. In the second operational state, the rigid mass then holds the trocar sleeve fixed in the desired spatial orientation. 
     In a further configuration, the material is a particulate material and the apparatus comprises means for generating a vacuum within the casing. In this configuration, the connecting member of the present apparatus is comparable to a balloon filled with a sand-like material. As long as the balloon casing additionally contains air or another gas, the material in the interior is formable. Correspondingly, this is the first operational state in which the connecting member is flexible. 
     By creating a vacuum in the casing, the air is suctioned out of the balloon, the particles are pressed against one another and the material loses its formability. The connecting member is rigid in this second operational state. The mentioned feature therefore represents a very simple technical possibility of realizing a connecting member where the operational states according to the present invention. 
     Furthermore, this embodiment has the advantage that the switching between the first flexible and the second rigid operational state is very rapid and simple with the aid of a valve and a pump. In addition, the necessary means for generating a vacuum are known per se in the field of clinical instruments and are also employed there. The present apparatus thus can be realized particularly inexpensively as a supplement to existing devices. A further advantage of this configuration is that the switching between the first flexible and the second rigid operational state is possible “simply by pushing a button” and if desired can be completely automated. 
     In a further embodiment, the surface of the particles of the material is configured such that the particles in the closely compressed condition are prevented from sliding past one another and therefore form a rigid mass. This is particularly the case when the particles have edges, so that the individual particles lie immovably upon one another or catch within one another in the pressed form. The feature has the advantage that a particularly high rigidity of the connecting member is achieved in the second operational state. 
     In a further embodiment, the material with adjustable rigidity is a fluid whose viscosity is adjustable between being elastic and rigid. Such materials are known per se in the prior art. They have a molecular structure where the molecules in different operational states are varyingly strongly coupled to one another and/or oriented with respect to one another. This leads to the fact that the fluids have differing viscosities in different operational states. This feature has the advantage that a very simple and fast reacting possibility is given to realize a connecting member according to the invention with the desired operational states. 
     In a further embodiment, the viscosity of the material is adjustable in response to an electric and/or magnetic field. These are electric or magnetic viscous fluids, whose molecular structure changes under the influence of the mentioned fields. Alternatively, fluids are known whose viscosity changes depending on pressure. This has the advantage that switching between the operational states according to the invention is very simple and “occurs practically by pushing a button” or when needed can be completely automated. 
     In a further embodiment of the apparatus, the connecting member comprises a material, which is flexible at a first adjustable operational temperature and is rigid at a second operational temperature. Preferably, the second operational temperature is room temperature, where the present apparatus is normally used. The mentioned feature represents a further, alternative possibility of realizing an apparatus with the connecting member according to the invention. 
     In a further embodiment, the connecting member is a torus-shaped body with the retainer being arranged in its opening. The feature has the advantage that the connecting member is arranged to surround the retainer and thus guarantees a flexibility or rigidity uniformly in all directions. In addition, a particularly high stability of the apparatus is achieved in the second operational state. 
     In a further embodiment, the base member is secured to a support frame, which can be adjustably and fixedly mounted to an operating table. 
     Alternatively, it is also contemplated to fix the present apparatus directly on the patient&#39;s body, either alone through its own weight or additionally by using a releasable adhesive. The former feature however has the advantage that the base and thus the entire apparatus can be held substantially more stable and secure with respect to the patient. It is insured that the apparatus is not inadvertently shifted through movements of the patient. At the same time it is ensured that the apparatus can always be positioned optimally with respect to the patient due to the adjustable, but fixed mounting on the operating table. 
     In a further embodiment, the support frame comprises at least one rail extending over the operating table, preferably in about the transverse direction with respect to the patient. The feature has the advantage that particularly good stability is achieved without the apparatus requiring too much space and obstructing access to the patient. In addition, such a rail can be arranged in simple manner such that the base member of the apparatus lies practically directly on the patient&#39;s body, where relative movement between the trocar sleeve and the patient is substantially excluded. 
     In a further embodiment, the base member is secured to the rail to be slidable. The feature has the advantage that the holding apparatus can be adjusted rapidly and in simple manner, and thus can always be disposed at the optimal position with respect to the patient. 
     In a further embodiment, the at least one rail along the operating table is shiftable and/or pivotal about a pivot point. 
     These features also contribute to enhancing the possibilities of use and the positioning capability of the present apparatus. At the same time, the operation of the apparatus is very simple and the apparatus does not represent an obstacle for access to the patient. Furthermore, compared to the variably adjustable, multi-link pivot arm, the embodiment is simple and inexpensive in construction and manufacture. In a further embodiment, the support frame comprises several rails, on which several base members with retainers and connecting members are secured. The advantage is that the stability of the apparatus is improved when using more rails. The use of several base members also has the advantage that several medical instruments can be fixed at the same time at different positions on the patient. 
     It will be understood that the above-mentioned features and those to be discussed below are applicable not only in the given combinations, but may also be used in other combinations or taken alone without departing from the scope of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention are illustrated in the drawings and will be described in more detail in the following description. 
     FIG. 1 shows a partially cross-sectional, perspective illustration of a first embodiment of the present invention. 
     FIG. 2 shows an operating table from above with several holding apparatus according to the present invention. 
     FIG. 3 shows an alternative configuration of an operating table with holding apparatus according to the present invention. 
     FIG. 4 shows the use of the present holding apparatus in cross-sectional view, where a medical instrument is fixed in a first position. 
     FIG. 5 shows the use of the present holding apparatus corresponding to FIG. 4, where the medical instrument is fixed in a second position inclined in comparison to the first position. 
     FIG. 6 shows a second embodiment of the present holding apparatus in a partially cross-sectional, perspective view. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     A holding apparatus according to the present invention is shown in FIG.  1  and designated generally with the numeral  10 . The holding apparatus  10  comprises a base member  12  secured to a rail  14  of a support frame shown only partially here. The base member  12  in the present case is a support ring to which a torus-shaped connecting member  16  is secured. The connecting member  16  can be adhered to the base member  12  or screwed thereto. In the present example, the connecting member  16  however is clamped to the base member  12  and thus can also be removed. In a further alternative embodiment, the base member  12  can be integrated into the connecting member  16 . In this case, the base member  12  consists substantially of a stiffened underside of the connecting member  16 . 
     The connecting member  16  comprises an elastic casing  18 , which in the present case is made of silicone. The casing  18  is filled with a particulate material  20  whose particles  22  have a surface with substantially flat portions and edges. Thus, the individual particles  22  catch with one another very well when they are compressed. 
     The torus-shaped casing  18  filled with the particles  22  surrounds an annular retainer  24  whose outer circumference is adhered to the casing. The retainer  24  consists of a material which is hard compared to the casing  18 , for example plastic, and alternatively to the embodiment shown here can also be formed to be hollow or to have channels. 
     A schematically illustrated trocar sleeve is designated with the numeral  26 . The trocar sleeve  26  has a tubular shaft  28 , which in the illustrated position is passed through the ring opening  30  of the retainer  24  and which expands to a hollow cylindrical valve housing  32  at its upper end. 
     Valve housing  32  of the trocar sleeve  26  normally has a valve flap for closing the shaft  28  and can also have a clamping device and/or one or more connectors. Such configurations of trocars or trocar sleeves are however known per se in the art and are not illustrated here for reasons of clarity. 
     An aerating and ventilating valve is designated with the numeral  34 , which is connected to a pump  38  by a line  36 . The valve  34  joins into the casing  18  of the connecting member  16  and has a sieve  40  whose mesh size is designed such that the particles  22  do not exit from the casing  18 . 
     Air or an arbitrary gas can be pumped into or suctioned off of the casing  18  of the connecting member  16  through the valve  34  by the pump  38 . The latter has the effect that a vacuum is generated in the casing  18 , which causes the casing  18  to collapse. The consequence is that the individual particles  22  of the material  20  lose their freedom of movement and are pressed together. This in turn has the result that the otherwise flexible connecting member  16  is then “fixed” in its given form. Since the rigid mass surrounds the retainer  24 , the rigid mass holds the retainer  24  in a certain orientation. The original freedom of movement of the particles  22  and thus the original flexibility of the connecting member  16  is returned when aerating the casing  18 . 
     The abdominal wall of a patient to be treated is indicated with the numeral  42 , through which the shaft  28  of the trocar sleeve  26  has been penetrated. The trocar sleeve  26  is thus tiltable about a so-called invariable point, which lies within the abdominal wall  42 , assuming that the apparatus  10  is in its first flexible operational state. 
     The dimensions of the connecting member  16  are indicated with the parameters D 1 , D 2  and H 1  and in the present case have the approximate values of D 1 =100 mm, D 2 =30 mm and H 1 =20 mm. 
     As an alternative to the present embodiment, where a particulate material  20  is used within the casing  18  and the rigidity of the connecting member  16  can be changed with the valve  34  and the pump  38 , the casing  18  can also be filled with a fluid whose viscosity is adjustable between being elastic and firm. 
     Preferably, the fluid is adjustable by applying an electric and/or magnetic signal. In this case, an electric connection or a magnetic coupling (not shown) is provided in place of the valve  34  and a corresponding field generator is necessary instead of the pump  38 . The casing  18  as well as its connection to the retainer  24  however can be realized in the same manner as shown in FIG.  1 . 
     The same also holds when a material is used for the material  20  which is flexible at a first adjustable operational temperature and is rigid at a second operational temperature. Corresponding means are required in this case, in place of the valve  34  and the pump  38  with which the temperature of the material can be changed as rapidly as possible. This can be a combined heating and cooling unit and the material is selected such that a distinct melting point is present in the region just above room temperature. 
     An operating table  50  in FIG. 2 is equipped for example with a total of 3 holding apparatus  10  and  52 ,  54  according to the present invention. It will be understood that an operating table can also be provided with only one or any other number of holding apparatus  10 . 
     The holding apparatus  10  is secured with its base member  12  on the rail  14  of the support frame mentioned in conjunction with FIG.  1 . The holding apparatus  52 ,  54  in contrast are secured to a bracket  56 , which is slidably mounted on two rails  58  in the direction of the arrow  60 . Furthermore, it is possible to dispose the apparatus  52 ,  54  along the width of the operating table in a desired position due to the shiftability of the holding apparatus  52 ,  54  in the direction of the arrow  60 . 
     The rail  14  as well as the two rails  58  are coupled via slide elements  62 ,  64  to slide rails  66 , which are secured to both sides of the operating table  50  in longitudinal direction. Due to the slide elements  62 ,  64 , it is possible to shift the rail  14  or the arrangement of the two rails  58  in longitudinal direction of the operating table  50 , i.e. in the direction of the arrows  68 . The slide elements  62 ,  64  can be rollers or other glide means and additionally be provided with adjustment means (not shown). 
     An operating table in FIG. 3 is designated with the numeral  70 . The present holding apparatus  72  are again secured with brackets  74  slidably mounted on rails  76  in the direction of the arrow  78 . In contrast to the previous embodiment, the two rails  76  however are mounted with one end rotatable or pivotal on plates  80 . The other end of the rails  76  is connected to a slide rail  82  by pins, not shown in more detail. The pins are disposed in a slotted hole  84  of each rail  76 , so that a compensation for length is made during rotation. The slide rail  82  in turn is secured to a longitudinal side of the operating table  70 . It is also possible with this arrangement to adjust the present apparatus  72  in longitudinal direction of the operating table  70 , i.e. in the direction of the arrow  86 . 
     The operation of the present apparatus will be described in conjunction with FIGS. 4 and 5. The same reference numerals are used for the same elements already discussed in conjunction with the above figures. 
     A medical instrument is designated with the numeral  90  which is passed through the trocar sleeve  26  into the body  92  of a patient to be treated. The medical instrument in the present case is a grasping forceps. 
     The trocar sleeve  26  in FIG. 4 is located approximately in the same position as shown in FIG.  1 . The shaft  28  of the trocar sleeve  26  is disposed substantially perpendicular. This orientation however is often not suitable to reach the desired location within the body  92  of the patient. Moreover, the medical instrument  90  must frequently be inclined when passing through the incision in the body  92  of the patient to reach a certain organ. 
     For this purpose, the present apparatus at the beginning of the treatment is placed in a desired position relative to the patient with the aid of the rails  14 ,  58  or  76 . The necessary incision into the body  92  of the patient is then made with the trocar, where the trocar sleeve  26  then remains in the patient&#39;s body  92  and can be oriented in the desired direction and angular position. The latter can be accomplished for example with the aid of an optical instrument, which in such cases is passed through the trocar sleeve  26 . 
     When finding the proper position, the connecting member  16  is in its first flexible operational state. When using the embodiment of FIG. 1, this means that the casing  18  is filled with air, so that the particles  22  of the material  20  within the casing  18  can shift. In this operational state, the trocar sleeve  26  along with the retainer  24  can be tilted relative to the base  12 , which causes the torus-shaped connecting member  16  to deform. 
     When the desired position is found, air is suctioned out of the casing  18  via the valve  34  by the pump  38 , where a vacuum then arises in the casing  18 . The connecting member  16  then is in its second rigid operational state and its last assumed form is fixed. At the same time, the retainer  24  and the trocar sleeve  26  are also fixed in the adjusted orientation. This condition is shown for example in FIG.  5 . 
     A second embodiment of the present holding apparatus is designated in FIG. 6 generally with the numeral  100 . The same reference numerals again are used for the same elements discussed above in the previous figures. 
     The apparatus  100  differs from the apparatus  10  in FIG. 1 essentially in that the connecting member  102  has a casing  104  which passes under the retainer  24 , so that the retainer is nearly completely embedded in the casing  104 . Furthermore, the edges  106  of the retainer  24  are distinctly rounded to avoid damaging the casing  104  when changing the position of the trocar sleeve  26 . The stability of the trocar sleeve  26  is enhanced, especially when it is strongly inclined in one direction, due to the underside support of the retainer  24  with the casing  104  and the material  20  contained in the casing. 
     In a further embodiment, not illustrated here, the retainer  24  can be integrated into the casing  104 . In this case, the head  32  of the trocar sleeve  26  then lies directly on the casing  104 .