FR2615397A1 - Continuous inflation ambulatory device with constant pressure of tissue expansion balloons (dilators) - Google Patents

Abstract

The invention relates to an ambulatory method allowing constant-pressure continuous inflation to be ensured in a tissue expansion balloon (dilator) intended to produce an excess of skin used to cover a loss of substance in a patient. It consists of a peristaltic pump 9 injecting a liquid 10 into a tissue expansion balloon (dilator) 11. The pressure of the liquid in the balloon is sampled 12 and measured by a sensor 1. After preamplification 3, the signal leaving the sensor is compared with a reference pressure value 5. The control circuit 7 will actuate the motor of the pump when the value of the pressure in the balloon 4 is less than the predetermined value 6.

Description

 The present invention relates to an ambulatory method for controlling the inflation of tissue expansion balloons to a predetermined pressure value.

 In plastic and restorative surgery, it is necessary to cover the loss of substances from the skin covering. To do this, we have had the TISSUE EXFARSION technique for a few years. This technique was invented in 1976 by FADOVAN.

 The treatment consists in implanting under the patient's skin a system comprising a silicone expansion balloon of variable shape (round, rectangular, etc.) which is connected via a tube to a non-return filling valve. .

 When the healing of the first route, necessary for the implantation is done, one begins to inject, manually with a syringe (or automatically with an electric syringe pump> via a transcutaneous needle, serum physiological by the non-return valve.

 At the end of a more or less long period of time (. Months on average), the balloon is completely filled with liquid at the rate of one or two inflation sessions per week.

 The skin, facing the balloon, is therefore expanded, like a tumor or more simply a pregnancy.

This excess of skin obtained will serve to cover a loss of substance and this, thanks to a completely normal skin and excellent aesthetic appearance.

However, the very length of the method imposes very heavy constraints on the part of the patient
- moral, because the aesthetic aspect is
particularly difficult to bear because
deformity caused by balloons.

- financial, because hospitalization of some
sick is essential for the duration of
treatment.

The method according to the invention makes it possible to shorten this expansion period by replacing the weekly inflations with CONTINUOUS inflation, at constant pressure, using a device designed around a peristaltic pump meeting certain criteria.
- It must be able to be controlled by a parameter
well defined: the pressure must not exceed
60 mmHg, because beyond there is a risk of
too strong compression of the skin and therefore of
necrosis of it.

- It must be autonomous and compact
to be worn on the belt and not
not prevent the patient from going about his
occupations.

 The general principle of the smbulatory process of continuous inflation, at constant pressure of a tissue expansion balloon, is as follows: a peristaltic pump with rollers is controlled by the pressure prevailing inside the balloon.

When the pressure is less than 60 mmig, the pump turns and injects liquid into the balloon. When the pressure reaches 60 mmHg, the pump stops. The elasticity of the skin is such that, quickly, the pressure in the balloon described and the pump starts again to fill the balloon.

 It should be noted that the threshold, currently set at 60 mmig, is adjustable using an external adjustment.

 The pressure is detected using a transducer driving the input of an amplification system and then servo-control of the pump control circuit.

Proof descrlption of diagrams
- Figure 1 shows the general block diagram of the ambulatory process of continuous inflation, at constant pressure of a tissue expansion balloon.

 - Figure 2 shows the electrical diagram of the assembly consisting of the pressure sensor and its preamplification stage.

 - Figure 3 shows the electrical diagram of the pump control circuit, and in particular the setting of the reference pressure.

Detailed description of the process implementation (Fig. 1)
A peristaltic roller pump (9) injects physiological saline (10) into the tissue expansion balloon
(11). The pressure in the balloon, taken in bypass
(12) on the supply line, is transmitted to a pressure sensor (1) consisting of a transducer mounted in the measurement bridge (see Figure 2>.

 When the pressure increases, the sensor delivers between (13) and (14) a proportional positive voltage which is collected and then amplified by a differential circuit constituted by the operational amplifiers (15), (16) and (17).

 The voltage from this measurement circuit is then sent by line (4) to one of the inputs of the control circuit (F) of the pump. This also receives on its input (6) a reference voltage adjustable by the potentiometer (5) (see Figure 3).

 This differential assembly constituted by the assembly comprising the operational amplifier (25> is designed in such a way that the resulting control voltage on line (50) decreases when the pressure in the balloonet [represented by the line voltage (4)] increases .

 The assembly is adjusted using a mercury column, connected to a pneumatic pump.

 The sensor (1) is excited by a pressure equal to the reference pressure (for example 60 mmHg> and the potentiometer (5) is adjusted to obtain a control voltage (line 50) canceling the rotation of the motor (99.

 It is checked that by decreasing the pressure in the balloon, the line voltage <4) decreases and the line control signal 50 increases, starting the pump motor until the reference pressure is reached.

 The supply and control circuit of the continuous motor of the pump is represented on the other part of FIG. 3. The operational amplifier (26) receives on its + input, the control voltage (50) coming from the comparator described. t, above, and on its input - the voltage from the generator ta chymétri que (30) adjusted by the potentiometer (27).

This arrangement allows inflation of the balloon at a regulated flow rate around an average value, avoiding any sudden variation or any oscillation around the reference pressure value, risking pain for the patient. It works as follows
- If the motor <9) is braked
the generator voltage (30) decreases,
the output voltage of (26) increases,
the output transistors (28) and (29) are saturated,
the motor (9) increases its speed.

- If the motor (9) rotates faster
the voltage of the generator (30) increases,
the output voltage of (26) decreases,
the transistors (280 and (29) conduct less,
the motor (9) decreases its speed.

Claims (2)

CLAIMS 1 Ambulatory device for continuous inflation at constant pressure of a tissue expansion balloon characterized in that it comprises  1 peristaltic pump (9) injecting a liquid (10> into a tissue expansion balloon (11) from which the value of the pressure (12) measured using a sensor (1) is taken, which, å through an amplifier stage (3), differentially compared to a reference pressure (5), the control circuit of the pump motor (7).  2 Device according to claim 1, characterized in that the speed3 of rotation of the motor (9) is regulated around a set value (27> by the action of a dynamotachymetric (30).