Patent Publication Number: US-2011060291-A1

Title: Device for injecting into an eyeball a sterile liquid selected from amongst perfluorocarbons

Description:
This invention relates to a device for injecting into an eyeball a sterile liquid selected from amongst perfluorocarbons 
     In particular, this invention refers to a new device that can be used in the surgical treatment of ophthalmic pathologies. Indeed, as described in U.S. Pat. Nos. 5,037,384, 5,336,175 and 5,792,099, for example, some ophthalmic pathologies, such as retinal detachments, are treated surgically by injecting a liquid into the eye which acts as a surgical endotamponade. In particular, in the case of treatment for retinal detachment, the liquid injected into the eyeball is chosen from the perfluorocarbon family. This liquid wholly or partly replaces the vitreous humour and thus, thanks to its high surface tension, is able to push against the detached or curled retina, spreading and remaining adherent to the inner wall of the eyeball to enable subsequent reattachment. 
     In accordance with consolidated practice, insertion of the aforementioned liquid compounds into the rear chamber is generally performed using a normal syringe which, following extraction from its packet (whose purpose is to keep the syringe sterile), is initially coupled with a needle. The surgeon then uses the syringe to make a hole in the rubber seal of the container of the sterile liquid compound and aspirates the required amount. 
     At this point, the needle is removed from the syringe and replaced with a canula for intraocular injection (normally fitted with a small hose coupling to allow the syringe to be kept far enough away from the area being operated on). 
     Alternatively, this same applicant has designed a package containing a syringe prefilled with the sterile liquid (described in European patent application EP 2 020 245 A1). In this case, the surgeon need do no more than extract the syringe from the package and attach the canula. 
     In all known forms of implementation, the dispensing of the sterile liquid into the rear chamber is performed manually by pressing the syringe plunger. 
     However, this recognized methodology presents several inconvenient aspects. 
     Indeed, first of all, in order to be implemented, it always requires the simultaneous intervention of two operators, the surgeon and his/her assistant. 
     Indeed, at the moment in which the perfluorinated liquid is injected, both the surgeon&#39;s hands are occupied: with one, he/she is holding the end of the canula dispensing the perfluorinated liquid or the syringe itself, while with the other, he/she is holding other surgical instruments (which vary from case to case). Consequently, the surgeon is unable to press the syringe plunger at the same time, which, hence, must be done by the assistant. 
     In the second place, the fact that it is the assistant dispensing the sterile liquid requires extreme coordination between the two operators. Indeed, to perform the operation in the best way possible, the fluid must be dispensed at the right speed according to the position of the canula within the rear chamber and the quantity of gas that is gradually aspirated. The entire operation is made even more difficult by the fact that the volume of the rear chamber is minute and the surgeon must observe through a microscope. 
     Furthermore, owing to the dimensions of the syringe, friction with the stopper as it moves and human limitations, it is almost impossible to guarantee that the sterile liquid is dispensed gradually and uniformly; on the contrary, the sterile liquid is normally dispensed in spurts. 
     U.S. Pat. No. 5,037,384 describes an alternative methodology where the sterile liquid is held in a containment chamber, basically consisting of a syringe cylinder with no stopper and plunger and closed on the top with a rubber seal. In this case, in order to use the liquid, the surgeon makes a hole in the seal using a needle connected to a pressurised air source and monitors the flow of liquid via a valve located near the dispensing canula (which, in this case, is rigid and has no coupling tubes). 
     However, this methodology also has its inconvenient aspects. Indeed, by injecting pressurised air directly into the sterile liquid, there is a risk of generating excessive pressure which may cause damage to the eye. Moreover, in this case too, it is difficult to activate the valve in such a way as to obtain a gradual flow. 
     In this situation, the technical aim behind the present invention is to create a device for injecting a sterile liquid chosen from the perfluorocarbon family into the eyeball which overcomes the aforementioned inconvenient factors. 
     In particular, the technical task of the present invention is to create a device for injecting a sterile liquid chosen from the perfluorocarbon family into the eyeball which can be used directly and autonomously by the surgeon, without the need for external assistance, which, at the same time, enables the gradual flow of the liquid. 
     Further, it is the technical task of the present invention to create a device injecting a sterile liquid chosen from the perfluorocarbon family into the eyeball which does not expose the patient&#39;s eye to unnecessary risks. 
     The specified technical task and the exposed aims are essentially achieved with a device for injecting a sterile liquid chosen from the perfluorocarbon family into the eyeball as described in the annexed claims. 
    
    
     
       Further characteristics and advantages of the present invention will appear in greater depth in the detailed description of some of the preferred, but not exclusive, methods of execution of a device for injecting a sterile liquid chosen from the perfluorocarbon family into the eyeball, which are illustrated in the annexed designs, where: 
         FIG. 1  shows an axonometric view of an adapter which is part of the device that is the subject of the present invention; 
         FIG. 2  shows the adapter in  FIG. 1  from a different angle and with no internal stopper; 
         FIG. 3  shows an axial section of a container body which is part of the device that is the subject of the present invention; 
         FIG. 4  shows an axial section of a portion of a tube for feeding pressurised fluid; 
         FIG. 5  shows the adapter in  FIG. 2  from below; 
         FIG. 6  shows the adapter in  FIG. 5  according to trace VI-VI; 
         FIG. 7  shows the adapter in  FIG. 6  coupled to a second end of the container body in  FIG. 3 ; 
         FIG. 8  shows the adapter in  FIG. 5  according to trace VIII-VIII; 
         FIG. 9  shows the adapter in  FIG. 8  coupled to the second end of the container body in  FIG. 3 ; 
     
    
    
     In its more general design form, the device in the present invention consists of two fundamental elements, a container body  3  which holds the sterile liquid  2 , and an adapter  4  which allows the liquid to be connected sealed to a source of pressurised thrust fluid. The sterile liquid  2  is a liquid  2  injectable into the eyeball and is chosen from the perfluorocarbon family. 
     In particular, the container body  3  is tubular and has a first dispensing end  5  and a second end  6 . As can be seen in the annexed figures, the container body  3  advantageously consists of the cylinder of a traditional syringe and advantageously made of glass. 
     The first end  5  is nozzle-shaped, has a smaller cross-section than the other end and can be connected during use to a dispensing means (such as a canula, not illustrated here as the variety is well known). Before use, the first end  5  is closed by a seal  7 . To enable attachment of the dispensing means, the first end  5  may also be fitted with a male or female Luer fitting. Luer fittings are standardised attachments in the medical sector, with a double male-female connector. A first part  8  of the fitting includes a male nozzle  9  which can be inserted in a sealed fashion into a female connector  10  hollowed out from the second part  11 ; furthermore, to ensure the tightness of the seal, the first part  8  is also fitted with an internally threaded bushing  12  mounted around the nozzle  9 , into which a threading can be mounted or plurality of radial teeth  13  shaped from the outside of a coupling  14  which defines the inside of the female connector  10 . Examples of Luer attachments can be seen in  FIGS. 3 and 4  (two second parts  11  referring to the identification in the previous paragraph) and  6 - 9  (two first parts  8  referring to the identification in the previous paragraph). Hereafter, male and female Luer fittings will be referred to as the first part  8  and the second part  11  respectively, as defined above (male-female identification is thus made with reference to the fluid duct). 
     The second end  6  is opposite the first end  5  and its cross-section corresponds essentially to the container body  3  (with the exception of the first end  5 ). In the design illustrated, moreover, the container body  3  presents a radial projection at the second end  6  consisting of two flat tabs  15  perpendicular to the main axis of the container body  3 , diametrically opposite it and coupled via a smaller edge  16  which is level with it (viewed in cross-section in  FIG. 7 ). 
     A first stopper  17 , made from flexible material is slid opportunely into the container body  3 , and opportunely at a distance from the second end  6 , (the first stopper  17  should preferably be coated with a flexible, polymer film which is inert to the sterile liquid  2  and opportunely consisting of a fluorinated polymer). The first stopper  17  divides the internal volume of the container body  3  into two chambers, a collection chamber  18  close between the first end  5  and the first stopper  17 , filled with sterile liquid  2 , and a thrust chamber  19  closed between the first stopper  17  and the second end  6 . 
     The seal  7  of the first end  5  may be opportunely made of the same material as the first stopper  17 . 
     The adapter  4  opportunely has the function of connecting the second end  6  of the container body  3  with a tube  20  for feeding a thrust fluid into the thrust chamber  19 . 
     For this purpose, in general, the adapter  4  includes, first of all, first connecting means  21  to attach the adapter  4  to the feed tube  20  and second connecting means  22  to attach the adapter  4  to the second end  6  of the container body  3 , as well as first seal means  23  to guarantee the fluid seal between the feed tube  20  and the adapter  4  and second seal means  24  to guarantee the fluid seal between adapter  4  and the container body  3 . 
     Further, the adapter  4  has at least one duct  25  for the passage of a thrust fluid, extending from an infeed section  26  to an outfeed section  27 . 
     The infeed section  26  is positioned for when the adapter  4  is attached to a feed tube  20  by the first connecting means  21 ; in this position, the infeed section  26  is in fluid connection with to the inside of the tube  20 . In turn the outfeed section  27  is positioned for when the adapter  4  is attached to the container body  3  by the second connecting means  22 ; with this layout, the outfeed section  27  is in fluid connection with the thrust chamber  19  of the container body  3 . 
     This way, the pressurised thrust fluid dispensed through the tube  20  can reach the thrust chamber  19  and create a uniform thrust on the first stopper  17 , creating a gradual shift towards the first end  5 , with consequent dispensing of the sterile liquid  2 . 
     In the preferred design form, the first connecting means  21  consist of a Luer fitting  11 ,  12 , male or female (female in the annexed figures) designed to connect to a corresponding Luer type connector  11 ,  12 , female or male respective (male in  FIG. 4 ), attached to the feed tube  20 . The first connecting means  21  also consist opportunely of the first seal means  23  (in fact the seal is guaranteed by the tightening of the Luer fitting  11 ,  12 ). 
     In the illustrated design, the second connecting means  22  made by dividing the adapter  4  into a first body  28  and a second body  29  which are hooked onto each other. Once hooked, the first body  28  and the second body  29  form a housing  30  for containing at least the second end  6  of the container body  3  (in other words, the housing  30  forms the second connecting means  22 ). In the annexed figures, in particular, the housing  30  is shaped to surround, lock and completely contain the radial projection of the container body  3 . 
     The first body  28  can be sealed to the second end  6  of the container body  3 . In particular, this can be achieved by attaching the first body  28  to the second end  6  in the same direction as the main axis of the container body  3  itself. In particular, the second seal means  24  consist of a projecting element  31  attached to the first body  28  and made of elastically deformable material (such as rubber), which can be inserted into the second end  6  in a sealed fashion (in this case, the duct  25  extends at least partly through the projecting element  31  itself). In the illustrated design, the projecting element  31  consists of a second stopper  32 , similar to the first, mounted onto a rigid support element  33  projecting from and part of the first body  28 . 
     As can be seen in  FIGS. 6 and 8 , the first body  28  consists of single block of material and includes a first main portion  34  mainly extending flat which has a first  35  on which the first connecting means  21  are mounted (consisting of a female Luer fitting  11 ,  12 ), and a second face  36  on which the second seal means  24 . Near the edge of the second face  36  a plurality of hooked teeth  37  are mounted. Presented in cross-section, each of these consists of a stem  38  which has an engagement head  39  designed to hook to the second body  29  as explained below. 
     The second body  29  has an annular shape shaped to match the outside of the container body  3  thus being able to slide along the container body  3  from the first end  5  towards the second end  6  hooking to the first body  28 . In particular, the second body  29  consist of a second main portion  40  extending mainly flat (essentially similar to the first main portion  34 ) and with a third face  41 , in practice connectable to the second face  36 , and a fourth face  42  opposite the third face, from which there extends cantilever-style a tubular element  43  the inside of which is shaped to match the outer wall of the container body  3 , the hole in the tubular element  43  extends as far as the third face  41  so that the second body  29  takes the overall shape of a bushing. 
     The second  36  and/or the third face  41  (only the latter is shown in the annexed figures) create the housing  30  for the radial projection of the container body  3 . 
     Further, the second main portion  40  also has on the third face  41  undercut seats  44  which can be engaged by the hooking teeth  37 . To hook the two bodies  28 ,  29  together, it is sufficient to push the teeth  37  into the seats  44 , deforming them elastically until they are hooked in. 
     In the illustrated design, the duct  25  is made through the first body  28  (and in particular through the first main portion  34 ), the rigid support element  33  and the second stopper  32 . 
     In its more complete design, the device that is the subject of the present invention may also include a tube  20  ( FIG. 4 ) with a first end  45  able to connect to the first connecting means  21  (e.g. it may have special third connecting means such as a Luer fitting  11 ,  12 ) and a second end able to connect to a source of pressurised thrust fluid (the second end, not illustrated in the annexed figures, will also be fitted with special connecting means to the source of pressurised thrust fluid). 
     Lastly, the various components of the device that is the subject of the present invention (container body  3 , adapter  4 , tube  20 , etc. . . ) may be held in one or several sealed container packages (not illustrated) with sterile air. A dispensing canula may also be inserted in these packages to complete the device). 
     The adapter by itself is part of the present invention  4 , provided it is destined to be used with container bodies of the type described above containing a sterile liquid  2  chosen from the family of perfluorocarbons. 
     The device that is the subject of the present invention functions as described above. 
     In particular, when ready for use, the surgeon removes the components from the package and, connects the adapter  4  to the syringe (if not already connected) and then connects the adapter  4  to the tube  20  and, possibly, connects the tube  20  to the source of pressurised thrust fluid. He or she can then remove the seal  7  of the container body  3  and connect the dispensing canula. 
     The surgeon may then insert the canula into the eye together with the aspirator (using both hands) and monitor the flow of the liquid  2  via the pedal control which is usually fitted on pressurised fluid equipment. 
     In the preferred designs of the present invention, the injection pressure supplied by the equipment is set at between 0.1 and 1.5 bars. Indeed, with pressures of between 0.2 and 0.3 bars, flow may be intermittent, while with pressures at 0.7 bars, the liquid flow can form continuously and gradually. 
     The present invention provides important advantages. 
     Thanks to the possibility of using a control pedal, on one hand, liquid can be dispensed by the surgeon himself/herself; on the other hand, the flow can be monitored with high precision and can take place continuously and gradually with no intermittence, given that the pedal controls the pressure within the thrust chamber. 
     Furthermore, the solution of injecting the thrust fluid behind the stopper, and not into the liquid, allows avoiding the risk of damaging the eye. 
     It is also important to note that the present invention is relatively easy to produce and the production costs of the invention are not very high. 
     The invention design can be subject to numerous modifications and variants, all within the inventive concept which characterises it. 
     All parts may be replaced with other elements that are technically equivalent, and in practice, all the materials employed, along with the shapes and dimensions of the various components, may be of any nature, according to need.