Abstract:
An operating table including a patient support; a block for supporting a patient&#39;s lower back which is moveable in relation to the patient support between a retracted position and a deployed position; an actuator having a first end portion linked to the patient support; and at least one mechanism for adjusting the block between the retracted and deployed positions including a first connecting rod articulatable relative to the patient support, the connecting rod being connected to a second end portion of the actuator for angular displacement and to the block for displacement of the block between the retracted position and the deployed position, and wherein the adjustment mechanism essentially rectilinear displaces the block between the retracted position and the deployed position.

Description:
RELATED APPLICATION 
     This is a continuation of International Application No. PCT/FR01/03587 (published as WO 02/47599), with an international filing date of Nov. 15, 2001, which is based on French Patent Application No. 00/16324, filed Dec. 14, 2000. 
    
    
     FIELD OF THE INVENTION 
     This invention pertains to an operating table of the type including a block for supporting a patient&#39;s lower back, the block being mobile in relation to the structure of the operating table between a retracted position and a deployed position; and at least one mechanism for moving the block between the two positions, the mechanism being equipped with an actuator having an end linked to the structure of the operating table. 
     BACKGROUND 
     The block with which operating tables are equipped is intended to raise the lower back of a patient lying on the operating table to facilitate certain surgical interventions which require a noteworthy stretching of the tissues at the level of the pelvis. This block is currently positioned in the medial region of the operating table. It is adjusted by the operating room personnel after positioning of the patient on the operating table. 
     Current surgical methods increasingly require the use of medical imaging means during operations. There is therefore the requirement that numerous devices must be installed around and under the operating table which leads to the necessity of reducing as much as possible the bulk of the operating table and in particular its side frames or uprights. Consequently, the block and especially its adjustment mechanism must be as reduced in bulk as possible. The solutions known to date for the movement of the block are not very satisfactory. In particular, it is known to provide blocks formed by an inflatable bag, the height of the block being adjusted by means of the amount of air introduced into the inflatable bag. When the bag is not completely inflated to obtain an intermediary elevation of the patient, the block is too soft which prevents satisfactory immobilization of the patient. 
     Also known are blocks whose adjustment mechanism comprises a rack integral with the block, the rack cooperating with a pinion gear driven by a motor integral with the table&#39;s platform. 
     Such an arrangement is relatively bulky because of the rack&#39;s displacement course, the rack passing over the table&#39;s side frames under the platform when the block is in the retracted position. 
     It would therefore be advantageous to provide an operating table equipped with a mobile block whose adjustment mechanism is not bulky. 
     SUMMARY OF THE INVENTION 
     This invention relates to an operating table including a patient support, a block for supporting a patient&#39;s lower back which is moveable in relation to the patient support between a retracted position and a deployed position, and an actuator having a first end portion linked to the patient support, and at least one mechanism for adjusting the block between the retracted and deployed positions including a first connecting rod articulatable relative to the patient support, the connecting rod being connected to a second end portion of the actuator for angular displacement and to the block for displacement of the block between the retracted position and the deployed position, and wherein the adjustment mechanism essentially rectilinearly displaces the block between the retracted position and the deployed position. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Better comprehension of the invention will be obtained by reading the description below presented solely as an example and with reference to the attached drawings in which: 
         FIG. 1  is a schematic view in perspective of an operating table according to the invention; and 
         FIGS. 2 and 3  are elevation views of the block and the adjustment mechanism, partially housed in a side frame of the table, the block being represented respectively in its retracted position and in its deployed position. 
     
    
    
     DETAILED DESCRIPTION 
     The invention is an operating table wherein the or each adjustment mechanism comprises a first connecting rod articulated in relation to the structure of the operating table, the connecting rod being connected to a second end of the actuator for its angular displacement and to the block for the displacement of the block between its retracted position and its deployed position. 
     According to particular modes of implementation, the invention comprises one or more of the following characteristics: 
     the or each adjustment mechanism has a second connecting rod providing the link of the first connecting rod to the block, the second connecting rod being linked to the block and to the structure of the operating table, with the first and second connecting rods being articulated in relation to each other; 
     the or each adjustment mechanism comprises a third connecting rod providing the link of the second connecting rod to the structure of the operating table, third connecting rod being articulated in relation to the structure of the operating table and in relation to the second connecting rod; 
     the axis of articulation defined between the first connecting rod and the second connecting rod is located between the axis of articulation defined between the second connecting rod and the third connecting rod and the linkage point of the block to the second connecting rod; 
     the axis of articulation defined between the first connecting rod and the second connecting rod is closer to the axis of articulation defined between the second connecting rod and the third connecting rod than the linkage point of the block to the second connecting rod; 
     the actuator is a rectilinear displacement actuator which is articulated at its first end in relation to the structure of the operating table and is articulated at its second end in relation to the first connecting rod; 
     the axis of articulation defined between the second end of the actuator and the first connecting rod is located between the axis of articulation of the first connecting rod and the structure of the operating table and the axis of articulation defined between the first connecting rod and the second connecting rod; 
     the axis of articulation defined between the second end of the actuator and the first connecting rod is closer to the axis of articulation defined between the first connecting rod and the structure of the operating table than the axis of articulation between the first connecting rod and the second connecting rod; 
     the axis of the actuator extends essentially perpendicular to the direction of displacement of the block; 
     the block is articulated in relation to the adjustment mechanism and it comprises stops limiting the angular passage of the block in relation to the adjustment mechanism; 
     the or each adjustment mechanism is designed for an essentially rectilinear displacement of the block between its retracted position and its deployed position; 
     the or each adjustment mechanism has at least one supplementary degree of freedom in relation to the structure of the operating table; and 
     the articulation provided at the first end of the actuator has at least one supplementary degree of freedom enabling a displacement between the actuator and the structure of the operating table perpendicularly to the axis of rotation. 
     Turning now to the drawings, the operating table  10  represented in  FIG. 1  comprises a base  12 , a support column  14  and a patient-support platform  16  attached to the top end of the column  14 . The platform  16  is constituted of a set of elements which are mobile in relation to each other to modify the configuration on which the patient rests. 
     In particular, the platform  16  comprises a central plate  18  forming a baseplate at one end of which is attached a leg rest  20  and at the other end of which is articulated a backrest  22 . In  FIG. 1 , the backrest  22  is represented as aligned in the extension of the support plate  18 . However, this backrest can be raised or lowered. The backrest is extended by a removable headrest  23 . 
     In the region of articulation of the backrest  22  on the support plate  18  is installed an articulated block  24 . This articulated block  24  is supported by two adjustment mechanisms  26  partially housed in the posts or side rails  28  of the baseplate support  18 . 
     The block  24  is constituted of a rectangular plate designed to support the patient&#39;s lower back. This plate can be slightly rounded. 
     The block is mounted such that it can be moved between a retracted position illustrated in  FIG. 2  in which the block  24  extends the baseplate  18  and is integrated with it and a deployed position illustrated in  FIGS. 1 and 3  in which the block  24  is mounted vertically in relation to the surface of the baseplate  18  and protrudes in relation to the surface of the baseplate. 
     The two adjustment mechanisms  26  for the block are identical; they are located at the two ends of the block  24 , i.e., at either end of the longitudinal axis of the table. 
     One of the adjustment mechanisms  26  of the block  24  is represented alone in  FIGS. 2 and 3 . 
     It comprises a rectilinear displacement actuator  30  which is constituted, for example, by a hydraulic screw jack connected to a source of fluid under pressure from the operating table system. 
     The actuator  30  is advantageously housed completely in the sidepiece  28 . Its axis extends essentially along the length of the sidepiece irrespective of the extension status of the actuator. 
     A first end  32  of the body of the screw jack is articulated around a hinge pin  34  in relation to the sidepiece  28  forming a structural element of the operating table. The hinge pin  34  extends perpendicularly to the sidepiece  28  and parallel to the surface of the baseplate  18 . 
     The articulation at the first end  32  comprises a hinge pin  34 A integral with the sidepiece  28 . The pin is received in an oblong slot  34 B in a tab  35  integral with the body of the screw jack. The large axis of the slot  34 B is directed along the direction of expansion of the screw jack  30 . 
     The end of the mobile rod of the screw jack  30  forming a second end  36  of the actuator is connected to a first connecting rod  38  of the adjustment mechanism. This first connecting rod  38  is articulated at one end  40  in relation to a sidepiece  28  along a hinge pin  42  extending parallel to the hinge pin  34 . 
     The second end  36  of the screw jack is articulated in the moving part of the first connecting rod  38  around a hinge pin  44 . 
     The connecting rod  24  is preferably connected indirectly to the other end  46  of the first connecting rod  38 . 
     For this purpose, the first connecting rod  38  is articulated in the running part of a second connecting rod  48  around a hinge pin  50 . The connecting rod  24  is connected at one end  52  of the second connecting rod  48 . This connection is advantageously constituted by a hinge pin  54 . 
     The hinge pin  54  extends along the width of the block thereby enabling a swinging upon itself of the block when supporting a patient which enhances the patient&#39;s comfort. 
     The hinge  54  has two stop designed to limit the angular passage of the block around a median position illustrated in FIG.  3 . In particular, these stops can prevent the block&#39;s edge from coming into contact with the patient. 
     At its other end  56 , the second connecting rod  48  is connected to the operating table&#39;s structure and more precisely to the side rail  28 . 
     For this purpose, a third connecting rod  58  is articulated from one of its ends  60  to the end  56  of the second connecting rod  48 . This articulation is implemented around a hinge pin  62 . 
     At its other end  64 , the third connecting rod  58  is articulated in relation to the side rail  28  around a hinge pin  66 . 
     All of the hinge pins of the adjustment mechanism  26  extend parallel to each other and transversely to the displacement plane of the screw jack  30  and the connecting rods  38 ,  48  and  58 . 
     Moreover, the hinge pins  34 ,  42  and  66 , respectively of the screw jack, the first connecting rod and the third connecting rod are aligned in relation to the side rail  28 . 
     Moreover and advantageously, in order to reduce the displacement course of the end  36  of the actuator and its angular passage around the hinge pin, the hinge pin  44  is closer to the hinge pin  42  than the hinge pin  50 . Similarly, on the second connecting rod  48 , the hinge pin  50  is closer to the hinge pin  62  than the connection point of the connecting rod  24  to the second connecting rod, i.e., the hinge pin  54 . 
     The adjustment mechanism represented in the figures enables an essentially rectilinear displacement of the block  24  along a direction extending perpendicularly to the plane defined by the baseplate  18  and the side rails  28 . 
     This displacement is implemented between a retracted position in which the adjustment mechanism is in the position illustrated in  FIG. 2 , and its deployed position in which the adjustment mechanism is in the position illustrated in  FIGS. 1 and 3 . 
     The displacements of the elements of the adjustment mechanisms  26  take place in parallel planes extending perpendicularly to the baseplate  18  and along the length of the table. 
     From the position of the adjustment mechanism illustrated in  FIG. 2 , when the screw jack  30  is activated, it pushes the first connecting rod  38  in the direction of the arrow F 1  so as to cause the angular displacement of it around the hinge pin  42 . Upon this displacement, the end  46  of the first connecting rod causes the lifting of the second connecting rod  48  in relation to the side rail  28 . In order to accomplish this, the third connecting rod  58  rotates around the hinge pin  66  in the direction of the arrow F 3 . Simultaneous with the lifting of the second connecting rod, it is displaced angularly around the hinge pin  62  under the action of the first connecting rod  38 , this angular displacement taking place in the direction of the arrow F 2 . 
     It can be understood that the angular displacement of the first connecting rod  38  according to a first direction combined with the angular displacement induced by the second connecting rod  48  in an opposite direction leads to a vertical displacement of the block  28  essentially along a rectilinear trajectory illustrated by the arrow F 4 . 
     Due to the position of the hinge pins  44  and  50  along the length of the first and second connecting rods, a slight displacement of the mobile end  36  of the screw jack causes a displacement of large amplitude of the block  24 . Moreover, the axis of the actuator always extends essentially perpendicularly to the direction of the displacement of the block  24 . 
     The displacement of the block  24  to its retracted position is attained in a similar and inverse manner under the action of the screw jack  30  pulling back the first connecting rod  38 . 
     In the retracted position of the block, the three connecting rods  38 ,  48  and  58  are housed inside the side rail  28 . They then extend along the length of the screw jack  30 . 
     The operating table described here has a block whose adjustment mechanism is of a greatly reduced bulk. In fact, it can be completely retracted within the side rails of the operating table when the block is in the retracted position. 
     The use of connecting rods articulated to each other makes it possible to avoid the use of elements that have to engage in translational motion with the exception of the screw jack, thus reducing the space required for the rectilinear displacement of these elements. 
     The presence of the oblong hole  34 B in the tab  35  provides a supplementary degree of freedom for the movement of the screw jack in relation to the pin  34 A. This degree of freedom makes it possible to limit the retraction of the block under the action of the actuator in the case in which an object or a limb might obstruct the displacement of the block. Thus, the risks of damage for an object or a limb caught under the block are reduced. In a variant, the supplementary degree of liberty of the adjustment mechanism can be obtained by implementation of an elastic connection tab  35 .