Abstract:
The invention concerns a device for observing a surgical field, comprising a flat monitor video ( 15, 40 ) and a chamber ( 20, 30 ) capable of being sterilized and forming a sealingly closed sterility barrier around the monitor video ( 15, 40 ), wherein the chamber ( 20, 30 ) is sufficiently sealed to maintain internal excess pressure or negative pressure applied on the closure of the chamber ( 20, 30 ), and the chamber ( 20, 30 ) is with an internal pressure sensor ( 160 ) for actuating alarm means when the excess pressure or negative pressure is no longer present, the assembled device being capable of being sterilized to infinity and of being used in all types of sterilized rooms, for example in a surgery or in a laboratory.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to devices for observing a surgical field, and in particular to such devices which are coupled to an endoscope. 
   Such devices are traditionally made up of an endoscopic camera which the surgeon guides manually in the patient&#39;s body, and of a video monitor which is placed a few meters away and on which the image recorded by the camera is displayed. 
   The surgeon uses a surgical instrument, guiding its leading end which appears on the screen. 
   Ordinary television screens of this kind are difficult to sterilize, so that surgeons have for many years contented themselves with keeping these screens away from the patient. 
   2. Description of Related Art 
   In the document WO 98/02107, a sterile enclosure for a flat screen has been proposed, consisting simply of a flexible envelope having substantially the shape of the screen and continuing via a sleeve around a part of a cord for powering the screen and for exchange of signals. 
   This document proposes closing this envelope around the cord and permanently drawing air inside this envelope in order to press it flat against the screen. 
   According to one variant, this document proposes placing a rigid enclosure around the screen, this enclosure having connection orifices intended to be hermetically closed when connected. 
   In this variant, after connection, a totally sealed envelope is obtained which permits sterilizing of the assembly by immersion without having to remove the screen from the enclosure. 
   However, such a device has an important disadvantage in that it is difficult to guarantee its sterility. 
   The sealing of the assembly rests entirely on the sealing between the enclosure and the cable connectors. This sealing is difficult to guarantee, especially as the cables are often moved or pulled and the connection is subjected to high forces. The hermetic closure between the sterile outside and the nonsterile inside of the chamber thus depends on particularly fragile means. 
   In addition, the rigid enclosure must be able to be opened and comprises for this purpose at least two parts which can be detached from one another. Complete sealing at the junction between these two components cannot be guaranteed for an indefinite number of sterilizations of the chamber, and air communication between the inside and the outside of the enclosure takes place at the level of this junction. 
   Such a device therefore cannot be considered as reliable. 
   The main object of the invention is to remedy this disadvantage. 
   BRIEF SUMMARY OF THE INVENTION 
   To do so, the invention makes available a device for observing a surgical field, said device comprising a flat video monitor and a chamber which is sterilizable and which forms a sterility barrier closed in a sealed manner around the monitor, characterized in that the chamber is sufficiently sealed to maintain an internal overpressure or underpressure applied upon closure of the chamber, and in that the chamber is provided with an internal pressure sensor which can activate alarm means in the event of the internal overpressure or underpressure disappearing, the assembled device being sterilizable to infinity and being able to be used in sterile areas of all types, for example in medical areas or in a laboratory. 

   
     DESCRIPTION OF THE DRAWINGS 
     Other characteristics, aims and advantages of the invention will become apparent from the detailed description which follows and in which reference is made to the attached figures, in which: 
       FIG. 1  shows a surgical viewing device according to the invention, in cross section; 
       FIG. 2  shows the same device in the same cross section, in an exploded view. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present viewing device is made up of a video display assembly  10  and of an articulated arm  100  forming a support for the display assembly  10 . 
   The display assembly  10  is made up of two main assemblies, namely a video monitor enclosed in a sealed chamber. 
   The video monitor is in the form of a liquid crystal screen  15  and an electronic module  40  connected to this screen by a wire connection  80 . 
   The screen  15  is here an active-matrix liquid crystal screen (LCD), of the type with microtips, from plasma technology, or from transistorless technology of the DEL type (Digital Electronic Luminescence). 
   In this embodiment, these two elements  15  and  40  are maintained in position relative to one another by the sealed chamber. 
   For this purpose, the latter is formed by two components  20  and  30 , each having a plane and rectangular general shape and with dimensions slightly greater than those of the screen  15 . 
   The element  30  will cover the whole rear face of the screen  15 . For this purpose, it has a part of overall rectangular shape and four rectilinear edges along the four edges of the screen  15 . 
   In its central part, this rear panel  30  extends away from the screen  15  in the form of a hump-shaped undulation whose concave part directed towards the screen  15  forms, at the rear of the latter, a cavity for receiving the electronic module  40 , and whose rear convex part continues as a sleeve  35  intended to be engaged in the support  100 . 
   More precisely, the internal cavity formed by this hump  30  has a parallelepipedal shape complementing that of the module  40 . Once the module  40  is in place in the internal cavity of this hump  30 , and the screen  15  is connected to the module  40 , the screen  15  receives via its front face the component  20  in the general form of a parallelepipedal receptacle whose bottom forms the front panel of the screen  15  and whose four raised edges cover the four edges of the screen  15 . 
   These four edges are high enough also to cover the four free edges of the rear panel  30  extending beyond the edges of the screen  15  and to cooperate with these, so that the two elements  20  and  30  form a closed chamber around the screen  15  and the module  40 . 
   To afford particularly reliable sealing of the assembly, a Teflon seal labelled  70  is arranged between these two elements  20  and  30 , in particular at their edge junction. 
   As can be seen from the exploded view in  FIG. 2 , this seal  70  is in this case a sheet which covers the whole of the front face of the rear panel  30  and is folded back about the four free edges of the rear panel  30 . These folds are sandwiched between the free edges of the panel  30  and the inner faces of the raised edges of the front cover  20 . 
   It will also be noted that the raised edges of the cover  20  form a bulge  22  on their inner face, the rear end of which bulge  22  stops before the end of the raised edge, in the form of a flat shoulder facing the panel  30  and intended to bear against a peripheral portion of the front face of the panel  30 . 
   Distributed about the cover  20 , this bulge  22  has threaded seats adapted to receive fixing screws which pass through the rear panel  30 . This screwing ensures a particularly strong pressing of the bulge  22  on the panel  30  with the Teflon sheet sandwiched in between. 
   The sheet  70  is thus sandwiched not only between the lateral ends of the panel  30  and the inner face of the raised edge of the cover  20 , but also between the bulge  22  and the front face of the panel  30  in such a way that the sheet  70  is subjected, irrespective of the position of the periphery of the panel  30 , to two gripping forces perpendicular to each other. 
   The sheet  70  here covers the whole of the panel  30  but it can be replaced by an annular element, for example of plane shape and parallel to the panel  30 , or of cylindrical shape and covering only the lateral edge of the panel  30 , or else of bracket-shaped cross section in order to receive both the lateral end and the peripheral edge of the front face of the panel  30 . 
   It will also be noted that the bulge  22  advantageously forms a groove open to the rear and inside of the cover  20  and receiving a complementary peripheral rib of the screen  15  in order to hold the latter by gripping it between the bulge  22  and the panel  30 . 
   The present components  20  and  30  are made of glass, which gives them a high degree of rigidity and complete transparency. This glass advantageously includes embedded particles able to form a barrier with respect to interferences which could adulterate the images displayed or various control signals described below. 
   The chamber can be made up of several components, of which only the part covering the front face of the screen  15  is made transparent. 
   The chamber can also be made of plastic, for example of Makrolon DP1-1262 marketed by Bayer, or of Noryl. 
   The electronic module  40  is connected to the screen  15  via a connection  80  simply arranged in the cavity of the hump  32 . 
   The module  40  is also continued via a second double connection which runs along the front face of the panel  30  and the raised edge of the cover  20  and opens out in the inner space of the chamber and has a pressure sensor  160  at this end. This double connection forms a second line of transmission which opens out on the front face of the cover  20  and has a voice sensor  150 . 
   The pressure sensor  160  sends a measurement signal to the electronic module  40  which then compares the measured pressure to a threshold value authorized for the internal pressure. This authorized internal pressure is, in the present example, a pressure markedly higher than atmospheric pressure. Indeed, the sealed chamber is set at an overpressure and then closed hermetically in a preliminary step, and the electronic module monitors the value of this overpressure during the course of time. 
   In the event of escape from the sealed chamber, that is to say in the event of the sealing between the sterile outside atmosphere and the nonsterile internal parts of the chamber being lost, an internal pressure drop detected by the electronic module  40  as falling below the threshold value is translated by the module  40  displaying on the screen  15  a visual warning indicating this loss of pressure. 
   According to one variant of the invention, the chamber can also be subjected to an initial underpressure, the module  40  alerting the user when this underpressure attenuates in an undesired manner. 
   The present device is provided with a channel  170  for fluid communication connecting the internal cavity of the hump  32  to the end of the support sleeve  35 . This channel  170  is closed at its end by a nonreturn valve. 
   After the chamber has been assembled, the sleeve  35  is engaged in a device which can inject a gas into the channel  170  until a sufficient pressurization of the chamber is obtained. Once the chamber has been separated from this pressurizing device, it maintains its internal pressure, by virtue of the arrangements which have just been described, with a particularly high degree of reliability. 
   The present display assembly can be sterilized several times without loss of overpressure, both by immersion and also by a process based on irradiation, such as the known STERRAD procedure. 
   A material of the Sterrad type permits sterilization at low temperature (about 45°) for a plasma gas of the hydrogen peroxide type and application of a radio frequency or gamma rays. The sterilization can also be carried out, for example, with a standard disinfecting product of the SIDEC type. 
   The assembly thus closed and sealed can therefore be used several times in an operating theater, with sterilization between each use. At each use, the operating team can check on the screen that the loss of pressure warning is not present and can thereby gain a guarantee of complete sealing of the chamber, and thus of its sterility. 
   The screen is placed a few centimeters above the patient&#39;s body, for example above the surgeon&#39;s hands, so that the practitioner only has to accommodate his vision over a short distance, which limits eye fatigue. 
   The present electronic module  40  additionally analyzes the signals from the sensor  170  in order, on the basis of these signals, to control different functions of the present screen  15  and also to transmit controls to other devices such as an endoscopy instrument (not shown). 
   To transmit or receive the images to be displayed, the module  40  has wire connections passing through the rear part  32  of the chamber and opening out on the rear outer face of this part. These wire connections have at their end electrical contacts  50  which are hermetically connected to the material constituting the part  32 , in order to ensure a high degree of sealing at their level. This sealed connection with contacts is in this case a sealed connection of the type with contact balls. 
   More precisely, the electrical connections run longitudinally along the sleeve  35  and the metal contacts  50  are distributed along the sleeve  35 . 
   The support  100  is an articulated support, with arms and articulations, the end portion of which forms a cavity  102  complementing the arm  35 , in order to receive the arm  35  and thus maintain the display assembly in the desired position. The articulations of the support  100  are preferably intended to be sealed for easy sterilization, in particular by immersion, of this support. 
   This cavity  102  of the support is also provided on its inner face with metal contacts which bear against the oil contacts of the arm  50 . These contacts are continued by electrical connections running through the assembly of arms and articulations of the support  100  and adapted to permit the movements of the articulations. 
   Thus, the engagement of the arm  35  in the corresponding cavity  102  of the support produces a mechanical support of the display assembly  10  and a signal exchange connection between the electronic module  40  and external electronic arrangements such as the endoscopy instruments and cameras (not shown). 
   A pin  110  is provided which passes through a lateral wall of the cavity  102  and lodges in a corresponding bore in the arm  35 . This pin  110  thus secures the arm  35  against accidental release from the cavity  102  and against rotation of the arm  35  in the cavity  102 . 
   In the present example, the contacts and connections of the support with the display assembly also convey electrical energy for powering the module  40  and the screen  15 . 
   According to one variant, the module  40  can also include a battery which is charged before joining-together and pressurization of the display assembly  10 . 
   According to another variant, the module  40  is continued via at least one electrical connection whose end carries an antenna for emission, reception, or both, of electromagnetic waves. The connections can also carry a light emitter, a light sensor or both. The sensors and emitters of the display assembly are, for example, infrared sensors and/or emitters. These elements for emission or reception of electromagnetic waves or light are preferably embedded in the material constituting the component  30 , at a location close to the outer surface of the component  30 . Thus, means for electromagnetic reception comprising a reception antenna are preferably placed at a location where the chamber has, between this antenna and the outside, a thickness which is less than the average thickness of the chamber. 
   The energy for powering the screen  15  and the module  40  is thus preferably transmitted in the form of such electromagnetic or light waves. 
   In these variants, the internal walls of the cavity  102  advantageously have electromagnetic or light receivers/emitters, each corresponding to the emitters/receivers of the display assembly. 
   Such contactless connection elements can also be elements of the induction type for transmitting signals or for transmitting the power. 
   In view of the features described above, the chamber and the elements which it surrounds form an assembly which is sterilizable to infinity, that is to say without consideration of a limited number of sterilizations fixed in advance. This is because the possible discontinuation of the sterilizations is indicated by the warning given by virtue of the pressure sensor. The internal pressure sensor or sensors guarantee effective and repeated sterilization and, in the absence of a warning, guarantee the perfect state of functioning and sealing of the device, in particular before and after sterilization. The assembly described can be used in sterile areas of any type, whether medical or not, such as an operating theater, laboratory, or areas where work is being carried out on bacteria whose development may be modified by the presence of nonsterile objects.