FR2779935A1 - Sterile liquid jet pulse train generating procedure e.g. for medical use - Google Patents

Abstract

The procedure uses a source of pressurized liquid and a vacuum source consisting of a continuous liquid jet and vacuum aspiration at the same recurrence frequency so that the liquid emerges from the hand piece in pulses at a set frequency and a pressure of 10 to 100 bars. The pulse and aspiration frequencies are variable between 0.1 and 10 Hz, and the duration of each output pulse starts and ends before the first half of the aspiration stroke.

Description

The invention relates to a method for generating a pulse train.

  of a sterile pulsed-aspirated liquid jet and the pulsed-aspirated liquid jet thus generated for feeding a handpiece for surgical applications. The use of pulsed jets of a sterile liquid under high pressure is already known for purposes

surgical procedures.

  One can quote for example for this purpose EP n ° 0636345 in the name of SENTINEL MEDICAL which relates to a surgical instrument with pulsed jet of liquid for purposes of cutting and emulsification with a joint aspiration for the evacuation of the liquid and the biological residues.

  The pulsed jet comes from the back and forth movement

  comes repeated from an amplifier piston which receives the

liquid under low pressure.

  The major drawback of this system concerns the use of a piston which can produce only one train of pulses during its working path along its stroke. It is then necessary to refill the piston chamber, which condemns this device to a discontinuous operation which is hardly compatible with the working requirements of the

surgeons.

  There are also inventions relating to eye surgery in which a pulsed jet of liquid is directed on the eye and in particular on the cornea for a work of disintegration of defective tissues and detachment of materials and bodies deposited or encrusted. These inventions are protected by US patents born 3, 818,913 and

3,930,505 in the name of WALLACH.

  These are high frequency pulsed jets intended by the high repetition rate for disintegration work for cleaning the lens by ridding it of defective tissues and foreign matter and bodies. There is conventionally provided a separate suction for evacuation

  liquid and residue from decay work.

  In these latter devices also the suction is continuous and separate. Furthermore, it is not a matter of cutting but of detachment and disintegration with a view to the removal of the materials and

bothersome fabrics.

  In general, the previously known high pressure pulsed liquid jets are trains of liquid pulses triggered on command and

  projected onto the dissection area.

  The sprayed liquid is then evacuated by continuous suction or when it exceeds a certain quantity deemed to be troublesome for the continuation of the dissection work. In these embodiments, the surgeon cannot approach the tissue to be dissected too closely from the end of the handpiece because of the lateral projections of liquid and the splashes thus generated, disturbing the visibility of the operating field. Furthermore, the dissection efficiency is only slightly better than that of a continuous jet.

  due to rebound phenomena.

  Finally, the penetration of even sterile liquid into the cut opening and this in small but not negligible quantities, is a disadvantage for the patient's body which must eliminate it in addition to

  all other intervention-related overloads.

  The present invention aims to remedy the aforementioned drawbacks by proposing a method for generating a pulse train of a sterile pulsed-aspirated liquid jet and a pulsed-aspirated jet thus generated for feeding a handpiece in view

surgical applications.

  To this end, the method according to the invention is characterized in that a pressurized liquid path, for example under high pressure and a pneumatic suction path, is used and that the firing is periodically controlled. of the pressurized jet during the periodic application of the suction and in that the fabric is released during the cutting of

aspiration by venting.

  The method according to the invention presents

many advantages.

  It avoids lateral projections and splashes of all kinds and therefore provides good visibility of the operating field at the same time as the possibility of approaching very closely

the fabric to be cut.

  In the case of a pulsed-aspirated jet, that is to say a jet drawn at the same time as the suction works, the fabric remains flattened, that is to say momentarily stretched before and during the firing at the end of the end sleeve of the handpiece then relaxes during the final phase of the aspiration. We thus shoot a stretched fabric which ensures precision

  and cleanliness of the cutting and the operating field.

  The duration of application of the jet is short,

  low consumption of sterile liquid is guaranteed.

  Other features and benefits of

  the invention will appear in the description which follows,

  given by way of nonlimiting example with reference to the drawing in which: FIG. 1 is a graph of the basic waveforms of the parameters of the pulse train as a function of time; Figure 2 is a graph of waveforms according to

  a first variant with a longer shooting time

  aunt; 35. Figure 3 is a graph of waveforms of

  shots not involving venting.

  The method according to the invention consists of all appropriate means, mechanical, electrical, electromechanical, electromagnetic ... to be generated on command from a first conduit of a sterile pressurized liquid delivered by a generator and a second pneumatic air suction line, a

  pulse train of a sterile pulsed liquid jet

  sucked. More particularly, one uses for each of the conduits on the one hand of liquid and on the other hand of suction a means of closing sequential opening of the flow rate at the same frequency and for a duration

different for the two fluids.

  According to the invention, the firing of the pressurized liquid jet, that is to say the opening of the closing-opening means of the liquid conduit takes place

  during the suction time intervals i.e.

  say during the opening time the means of

  closing-opening of the suction duct.

  The process is completed in that the suction is neutralized by vacuum of air immediately after the closing of the suction duct or the suction duct is placed in the air for

stop aspiration.

  The method can be implemented by simple means such as electromechanical means with pushers or others acting by pinching or crushing on a flexible conduit conveying the liquid or the air sucked in or by hydraulic cut-off components such as flow shutters or solenoid valves all controlled by a circuit

sequencing electronics.

  It is the same for the means of periodic airing of the suction pipe allowing to take off the fabric to be cut from the suction end

  of the handpiece for which the cut-off means

  opening by component will be pneumatic and no longer hydraulic. It is preferably carried out with air through the suction duct for example by bypassing it periodically open and closed, but any other way to compensate for the suction force to relax the tissue is possible. We will now explain the process by

different waveforms.

  The main characteristic phases of each period of the pulse train according to the invention are the following identified by the numbers from 1 to 5

in figure 1.

  phase 1: start of aspiration, phase 2: firing of the pressurized jet for a short time inside the aspiration pulse, 15. phase 3: continuation of the aspiration after firing, phase 4: venting during cut-off of suction, phase 5: continuation of cut-off of suction

until the next period.

  The following general characteristics are noted on observation of the figures. The shooting takes place with a certain delay compared to the beginning of the aspiration. The shooting preferably takes place in the first half of the pulse width of the suction and preferably stops before the start of the second half. The venting takes place after cutting off the suction and preferably but not

  obligatorily just after this cut.

  The main characteristic values of the parameters of the impulse train of pulsed-aspirated pressure liquid jet corresponding to that shown are given by way of non-limiting example.

in figure 1.

  recurrence frequency: 1 Hz 35. firing pulse width: 100 ms suction pulse width: 400 ms suction rest: 600 ms venting pulse width: 300 ms offset between end of the suction pulse and

venting: very low.

  The venting is short and immediately follows the end of suction. The rising edges of the pulses are shown vertical. In practice, the slope will depend on the type of closing-opening device

  of flow used and in particular of its inertia.

  Other different waveforms are possible. Thus, the frequency of recurrence of the pulse regime and the width of the pulses can vary. These variations depend on the surgical application, namely the type of intervention, organ or tissue targeted as well as the depth

  intervention in the human body.

  The device generating this controlled pulse train will make it possible to vary these main

  parameters including time parameters.

  It should be noted that the more the width of the firing pulse increases the more that of the suction must increase in order to be able to completely evacuate the

liquid and residue (s).

  FIG. 2 shows waveforms based on the same principle of a liquid jet under pulsed-aspirated pressure which is the subject of the invention. It is noted that the duration of the shot and the duration of aspiration increase simultaneously. Indeed, the longer the duration of the shot, the longer the suction must last to be able to

  evacuate all the sprayed liquid and solid residues.

  Correlatively, the control pulses or the openings corresponding to the vent move on the time axis to start just after the cut

suction.

  Figure 3 shows waveforms without venting. This example of application is that of a handpiece with an end sleeve open on its periphery for which the relaxation of the tissue after the firing takes place automatically after the cut of the aspiration.

Claims (13)

  1. Method for generating, on command, an impulse train of a sterile liquid jet for a handpiece, in particular for surgical applications by successive periodic commands according to a frequency of recurrence of shots of elementary jets of liquid under pressure putting in operates a pressurized liquid pathway connected to a pressure source and a suction pathway connected to a vacuum source characterized in that one: controls the firing of the elementary jets by periodically cutting the flow of the flow periodically pressurized liquid feeding the handpiece and it is cut before the end of the recurrence period, controls the suction periodically at the same recurrence frequency, periodically cuts the suction at the same recurrence frequency before the next periodic control of firing of the liquid jet under pressure,   creating a pulsed-sucked jet.   2. Method according to claim 1 characterized in that the pressurized liquid is   generated and expelled under high pressure.   3. Method according to the preceding claim characterized in that the high pressure is around of 100 bars.   4. Method according to any one of   previous claims characterized in that   controls the periodic firing of the pressurized jet during   the periodic duration of the application of the suction.   5. Method according to the preceding claim characterized in that one controls the periodic firing of the pressurized jet in the first half of the   period of application of the suction.   6. Method according to claims 4 and 5   characterized in that the period of time for which the pressure jet is fired ends before the first half of   the periodic aspiration pulse.   7. Method according to claim 1 or 2 characterized in that the suction is followed after its cutting by compensation for the suction effect for relax the fabric.   8. Method according to the preceding claim characterized in that the compensation for the suction effect is a venting during the cut of the suction. 9. Method according to the preceding claim characterized in that one proceeds to the venting through the suction pipe.   10. Method according to claim 1 characterized in that the frequency of recurrence is changeable. 11. Method according to the preceding claim, characterized in that the frequency of recurrence is situated in a range delimited by a fraction of Hertz and some Hertz.   12. Method according to the preceding claim characterized in that the frequency of recurrence is around 1 Hz.   13. Jet of sterile liquid under pressure for a handpiece in particular for surgical applications obtained by the method according to one   any of the preceding claims characterized   in that it is pulsed-aspirated at a frequency of recurrence.