FR2778549A1 - Heating clips with shape memory, particularly applicable to surgical operations - Google Patents

Abstract

The equipment comprises a box (1) housing supply, control and regulating units which feed switched (8) electrodes (7) through a plug and socket (5,14) and cable (4). The regulating unit may be set (12) to ensure that the correct amount of heat is supplied through the electrodes to close various sizes of surgical clips which are heat shrinkable and have a shape memory. The plug, cable and electrodes (5,4,6,8) may be readily sterilized

Description

The present invention relates to a device for heating and closing

  heat-shrinkable memory clips used in surgery.

  It is specifically designed to heat staples made of NickelTitanium alloy called "hot staples" which are open at room temperature for their installation and require the addition of a quantity of heat to close and thus maintain the tissue.

  Surgical, normative economic and ergonomic constraints impose extremely restrictive specifications.

  In addition, one of the objects of the invention is to provide an apparatus which can be used to close all types of staples, whether they are monocortical or bicortical staples, bipods or quadripods and

whatever their section.

  Another object of the invention is to equip the device with an effective and reliable safety system to prevent accidental bone necrosis due to heat.

  Another object of the invention is to design an apparatus the heating cord of which can be sterilized in an autoclave or disinfectable in a bath.

  All these aims are achieved by the invention which consists of a device for heating and closing heat-shrinkable memory clips used in surgery, device comprising a box enclosing an electronic power and control circuit, a power cord to the mains , characterized in that it further comprises a sterilizable assembly formed by a connecting cord terminated at one end by a plug-in plug on the outlet of the electronic circuit and at its other end by a sleeve carrying the two heating electrodes and a control switch, in that all the elements making up the sterilizable assembly

  support autoclaving. In addition, the sterilisable assembly is completely sealed. According to a preferred embodiment, the control switch is a switch with sensitive contacts.

  Preferably, the electronic circuit essentially consists of a current supply block, a control block and an adjustment block making it possible to deliver several predetermined quantities of heat each corresponding to a given size of staple. For safety purposes, the adjustment block is calculated so that the quantity of heat delivered to a staple does not generate in it a temperature exceeding a maximum value,

for example 55.

  Also for security purposes, the electronic circuit further comprises an automatic circuit breaker block cutting the heating current after a predetermined maximum time, for example 5 seconds. Also for security purposes, the electronic circuit further includes a block of

  sound signal emitting a first sound signal during the heating time and a second sound signal, different from the first if the maximum heating time is exceeded.

  The invention will be better understood using the following description made with reference to

  attached figures below; - Figure 1 schematic overview of the device according to the invention - Figure 2: functional diagram of the electronic circuit of the device according to the invention - Figure 3 detailed diagram of the electronic circuit; - Figure 4 sectional view of a sleeve according to the invention

  - Figure 5 detail view of the front of the housing.

  As shown in FIG. 1, the device according to the invention essentially consists of a box (1) enclosing an electronic power and control circuit, a mains supply cord (2), an assembly sterilizable (3) formed of a connecting cord (4), terminated at one end by a plug (5) pluggable into an outlet (14) of the electronic circuit and at its other end by a sleeve (6) carrying the two electrodes heater (7) of the clip and a control switch (8). The front face of the box (1) (Figure 5) is equipped with a main switch (9), a fault indicator light (10), a power-on signal (11), a button (12) potentiometer for adjusting the quantity of heat, a warning lamp (13) for heating the

  electrodes (7), and an output plug (14) into which the sterilizable assembly (3) is connected.

  The rear face, not shown in detail, is conventionally equipped with a nameplate and with the network outlet (2).

  We now refer to Figures 2 and 3.

  The electronic circuit consists of - a current supply A: It includes two transformers TR1 and TR2 whose primaries are connected to the

network.

  The transformer TR1 is a short-circuit resistant plate transformer, the secondary of which supplies a 12V voltage supplying the control block C, the circuit breaker block D, and the signaling block E. The transformer TR2 is a toroidal transformer with screen effect which the secondary delivers

  a current of 20 A at 4V and is used to supply the heating electrodes (7).

  The transformers are energized by action on the main switch SW3 of FIG. 3, itself controlled by the button (9) (FIG. 1).

  The transformers fulfill, in addition to their power supply function, a safety function isolating the patients and the sector.

  - an adjustment block B The phase attack of the power supply is connected to the primary of the transformer TR2 and consists of a triac TH1, a diac TH2 and a phase shift circuit R1 1, C 10. The triac TH1 switches from 0

  at the maximum value, each time the current alternates in a very short time.

  The blocking time is adjusted by the diac TH2 and the potentiometer R1 3 operated by the button (12). The button (12) is calibrated from 1 to 10, each graduation corresponding to a predetermined amount of current for a given size of clip. For example, for a load between electrodes of 0.1 W and 50 W, and a nominal current of 1A, the voltage measurements at positions 1, 5, 10 of button (10) are respectively

0.9V + 20%, 1.4 + 20%, 2.0V + 20%.

  Positions 1 to 5 are used for a range of monocortical and bicortical staples of different dimensions comprising from 0.8 g to 1.7 g of alloy and positions 6 to 10 for a range

  epiphyseal staples containing up to 2.8 g of alloy.

- a C control block

  Its purpose is to coordinate the functions of the system.

  Heating of the clip must be triggered by the control switch (8).

  This drives the relay K2 and the contact k2 1 sets the capacity C7 to zero volts. At the same time, contact k2 2. sets the clock U3 to + 12 V. - an automatic circuit breaker block D For safety reasons, this block allows the heating to be automatically cut off beyond a predetermined duration, thus limiting the amount of heat delivered to the clip to avoid any risk of necrosis even if for example the surgeon forgets to turn off the switch (8). The clock U3 is the main element of the short-circuit block D. The times are adjusted from 0 to 17 s by the counter and then adjusted by the regulator R1 7. A positive voltage is applied to the input of the clock of so that when stopped, the output (S3) of the clock has a potential and the relay K1

  either fell. The relay contact k2.1 sends the time sequence. Relay k1 is attracted and falls back when the determined time has elapsed.

  - an optical and audible signal block E

  A warning light (11) comes on to signal that the power is switched on when the SW3 contacts are closed.

  An indicator light (13) at L.E.D. (light-emitting diode) D6 and an acoustic signal LA1 indicate the operating state.

  The indicator light (13) comes on when the control switch (8) is closed.

  At the same time, a voltage is established on the relay contact k2.2 of the modulator U2.

  This is activated and induces modulation pulses in the sound signal LA1.

  The modulation pulses are sent by gates U4 to the base of a transistor Q2 which is brought to O volt by intervals.

  If the control switch (8) is kept pressed after the time has elapsed, the

  indicator (13) remains on and the audible signal emits a continuous sound.

  The electronic circuit also includes other components, the mounting of which does not

  no difficulty for the skilled person.

  We will now refer to Figure 4 which shows, seen in section, the sleeve (6) holder

  electrodes. The sleeve (6) has for example, but not limited to, a cylindrical shape

  hollow, but any other ergonomic shape facilitating the grip by the surgeon may be suitable.

  Two conductive wires (15,16) are connected to two contact zones (8a, 8b) of a touch switch (8) connected to two heating electrodes (7a, 7b) held parallel to the end of the sleeve (6 ) and conventionally insulated by an insulating sleeve (17). A driver

  central (18) ensures earthing.

  The connection cord (4), sleeve (6) and plug (5) assembly is made of sterilizable materials in an autoclave supporting up to 1340 C. It also comprises a seal (19) at the connection ( sleeve-cord) to also allow sterilization by immersion in

user choice.

  A reinforcement (20) at the bead outlet prevents kinks and protects the conductive wires

(15,16,18).

  For the installation of a staple, the surgeon proceeds as described below - preparation and positioning of the bone fragments, - installation of the drilling guides on either side of the fracture, - drilling of the holes , - installation of staples, one after the other in drilling, - powering up of the device by the main switch (9) and choice of the position of the button (12), - pressing the sleeve on a clip and start of heating as soon as the current is established by contact with the

  finger on the switch (8). The audible signal is then intermittent.

  The current is interrupted by the surgeon as soon as the clip is closed or, failing this, after five seconds thanks to the automatic circuit breaker D. The audible signal is then continuous and warns

the surgeon.

  The possibilities and qualities of the invention are in particular the following - heating of any type of clip. For this purpose, the 15 mm spacing of the electrodes allows, in a single application, to heat the dorsal part of small and medium staples, for larger staples, first heat one end of the dorsal part, then the 'other, which has the effect of successively bending the branches; - limitation of the quantity of heat delivered and limitation to 55 of the temperature that can be reached by the alloy; - limitation of the duration of application of the heating; - sleeve completely liquid tight

  -not causing any risk of explosion since the contact used does not create an electric arc.

  The invention also relates to heat-shrinkable memory staples used in surgery, designed to be closed by the heating device described above, and comprising

  an amount of nickel-titanium alloy which can vary from 0.8 g to 2.8 g.

Claims (10)

  1. Device for heating and closing heat-shrinkable memory clips used in surgery, device comprising a box enclosing an electronic power and control circuit, a power supply cord (2), characterized in that it comprises in addition a sterilizable assembly (3) formed of a connecting cord (4) terminated at one end by a plug (5) 5 which can be plugged into the outlet (14) of the electronic circuit and at its other end by a sleeve (6) carrying the two heating electrodes (7) and a control switch (8), in that all of the   elements making up the assembly (3) can be sterilized in an autoclave.   2. Device according to the preceding claim, characterized in that the control switch (8) is a switch with sensitive contacts.   3. Device according to one of the preceding claims, characterized in that the circuit   electronics consists essentially of a power supply unit A, a control unit C and an adjustment unit B allowing the delivery of several quantities of predetermined heat each corresponding to a given size of staple. 4. Device according to the preceding claim, characterized in that the adjustment block is calculated so that the quantity of heat delivered to a staple does not generate in it a   temperature exceeding a maximum value.   5. Device according to the preceding claim, characterized in that the maximum temperature is 55.   6- Device according to one of claims 3 to 5, characterized in that the electronic circuit   further includes an automatic circuit breaker block D cutting the heating current at the end of a predetermined maximum time.   7. Device according to the preceding claim, characterized in that the maximum time is set at 5 seconds.   8. Device according to one of claims 3 to 7, characterized in that the electronic circuit   furthermore comprises an audible signaling unit emitting a first audible signal during the heating time and a second audible signal, different from the first if the maximum time of heating is exceeded.   9. Device according to one of claims 1 to 8, characterized in that the assembly (3) is   waterproof and in that the sleeve (6) has a seal (19) at the sleeve-cord connection.   10. Heat-shrinkable memory clip used in surgery, characterized in that it comprises a quantity of nickel-titanium alloy which can vary from 0.8 g to 2.8 g and in that it is   designed to be closed by the device according to one of claims 1 to 9.