JP2011156314A - Fluid injection apparatus - Google Patents

Abstract

A fluid ejecting apparatus capable of stabilizing a resection depth and performing a safe operation is provided.
A fluid ejecting apparatus includes a fluid chamber, an inlet passage and an outlet passage communicating with the fluid chamber, and a piezoelectric element and a diaphragm as volume changing means for changing the volume of the fluid chamber. 40, a fluid ejection opening 96 provided at the end opposite to the fluid chamber 80 of the outlet channel 82, and a pump as a fluid supply unit that communicates with the inlet channel 81 and supplies fluid to the fluid chamber 80 10 and is set so that the fluid ejection speed of the fluid that is pulsed and ejected from the fluid ejection opening 96 exceeds four times the average flow velocity of the fluid supplied from the pump 10. As a result, since the variation in the excision depth is extremely small, it is possible to provide the fluid ejecting apparatus 1 that can perform a safe operation by eliminating the risk of damaging the tissue to be left regardless of the operator's procedure.
[Selection] Figure 2

Description

  The present invention relates to a fluid ejecting apparatus that changes a volume of a fluid chamber by a volume changing unit and pulsates and ejects a fluid.

2. Description of the Related Art Conventionally, methods for excising, incising, and crushing biological tissue using a fluid ejecting apparatus have excellent characteristics as a surgical tool, such as being free from thermal damage and preserving tubule tissue such as blood vessels.
As such a fluid ejecting apparatus, fluid ejecting is performed by supplying liquid from a pump to a tube introduced into a body cavity at a high pressure, ejecting the liquid at a high speed from a nozzle at the distal end of the tube, and excising the tissue in the body cavity by the fluid pressure. There is an apparatus (for example, refer to Patent Document 1).

  In addition, the volume of the fluid chamber is rapidly changed by the volume changing means, the fluid is converted into a pulsating flow, and is ejected from the nozzle at a high speed in a pulse form. There is a fluid ejecting apparatus (see, for example, Patent Document 2).

JP 63-99853 A JP 2008-82202 A

The fluid ejection device according to Patent Document 1 described above is a system that ejects a continuous flow at a high speed, and injects a flow rate several to several tens of times with a high-pressure pump as compared with the Pal flow method to perform excision of a living tissue. . Therefore, since the fluid flow rate is large, it is difficult to secure a visual field of view, and powerful suction is necessary as a solution.
Further, the fluid ejection device according to Patent Document 2 is a system that ejects a pulse flow at a high speed, and does not disturb the visual field of view because the flow rate required for resection is extremely small compared to the continuous flow system.

  The two methods described above have excellent tissue selectivity, and for example, it is possible to excise a tumor while leaving only blood vessels that penetrate the tumor. However, when the fluid ejection device is used as a surgical scalpel, not only the vicinity of the scalpel tip, such as an electric scalpel or an ultrasonic scalpel, is cut off, but also the cutting is performed in the axial direction of the fluid jetted over time by the jet of fluid. proceed.

  Therefore, when used in actual surgery, it is necessary to continue moving the fluid ejecting unit of the fluid ejecting apparatus at a constant speed, and when the speed varies, the excision depth also varies. Furthermore, if the movement is stopped, there is a risk that the tissue is to be excised in the depth direction and the tissue to be left is excised.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 A fluid ejecting apparatus according to this application example includes a fluid chamber, an inlet channel and an outlet channel communicating with the fluid chamber, volume changing means for changing the volume of the fluid chamber, and the outlet flow. A fluid ejection opening provided at an end opposite to the fluid chamber of the channel; and a fluid supply unit that communicates with the inlet channel and supplies the fluid to the fluid chamber. The fluid ejection speed of the fluid pulsed by the volume changing means and ejected from the fluid ejection opening with respect to the average flow velocity of the fluid supplied from the fluid exceeds 4 times.

  Here, the average flow rate is a flow rate obtained by dividing the flow rate of the fluid supplied from the fluid supply unit by the cross-sectional area of the fluid ejection opening, and when the volume changing unit is not driven, that is, the volume of the fluid chamber is constant. This is the flow rate when the fluid is jetted continuously in the state. Note that when the fluid is ejected at an average flow velocity, the living tissue is not excised.

  In this way, by setting the fluid ejection speed of the pulsed fluid to a speed exceeding 4 times the average flow velocity, the excision depth becomes substantially constant after a certain period of time while having excellent excision ability, and the operator Even if the position of the fluid ejection opening is not moved continuously at a constant speed, since the variation of the excision depth is extremely small, the risk of damaging the tissue to be left can be eliminated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration explanatory diagram illustrating a fluid ejection device according to a first embodiment. Sectional drawing which shows the cut surface which cut | disconnected the pulsating flow generation part which concerns on Embodiment 1 along the injection direction of the fluid. Explanatory drawing which represents typically the test method which excises gelatin. A graph showing the relationship between excision time and excision depth in the case of pulsed flow and continuous flow. The graph which shows the relationship between cutting time and cutting depth for every nozzle diameter.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(Embodiment 1)

  FIG. 1 is a configuration explanatory view showing a fluid ejecting apparatus as a surgical instrument according to the first embodiment. In FIG. 1, a fluid ejecting apparatus 1 includes a fluid supply container 2 that contains a fluid, a pump 10 as a fluid supply means, and a fluid supplied from the pump 10 in a pulsating flow (hereinafter sometimes referred to as a pulse flow). And a pulsating flow generation unit 20 that converts the pulsating flow. The pump 10 and the pulsating flow generation unit 20 are connected by a fluid supply tube 4.

  The pulsating flow generator can be adapted to any method that can convert fluid into pulsating flow and jet it in a pulsed manner, such as a piezo method using a piezoelectric element or a bubble jet (registered trademark) method. However, the pulsating flow generation unit described below will be described by exemplifying a piezo method.

  The pulsating flow generation unit 20 is connected with a thin pipe-shaped connection flow channel tube 90, and a nozzle 95 having a fluid ejection opening 96 with a reduced flow channel diameter is inserted into the distal end portion of the connection flow channel tube 90. ing. The connection channel tube 90 has such a rigidity that it does not deform during fluid ejection.

  The flow of fluid in the fluid ejecting apparatus 1 configured as described above will be briefly described. The fluid stored in the fluid supply container 2 is sucked by the pump 10 and supplied to the pulsating flow generation unit 20 through the fluid supply tube 4 at a constant pressure. The pulsating flow generation unit 20 includes a fluid chamber 80 (see FIG. 2), and a piezoelectric element 30 and a diaphragm 40 as volume changing means for changing the volume of the fluid chamber 80. Is driven to generate a pulsating flow in the fluid chamber 80, and the fluid is ejected from the fluid ejection opening 96 in a pulsed manner at a high speed via the connection channel tube 90 and the nozzle 95.

  When the pulsating flow generation unit 20 stops driving, that is, when the volume of the fluid chamber 80 is not changed, the fluid supplied from the pump 10 at a constant pressure passes through the fluid chamber 80 and flows into the fluid ejection opening. The continuous flow is ejected from the section 96.

  Here, the pulsating flow means a fluid flow in which the fluid flow direction is constant and the fluid flow rate or flow velocity is accompanied by periodic or irregular fluctuations. The pulsating flow includes an intermittent flow in which the flow and stop of the fluid are repeated. However, since the flow rate or flow velocity of the fluid only needs to fluctuate periodically or irregularly, the pulsating flow is not necessarily an intermittent flow.

  Similarly, ejecting fluid in pulses means ejecting fluid in which the flow rate or movement speed of the fluid to be ejected varies periodically or irregularly. An example of pulsed injection is intermittent injection in which fluid injection and non-injection are repeated. However, since the flow rate or moving speed of the fluid to be injected only needs to fluctuate periodically or irregularly, it is not always intermittent injection. Need not be.

Next, the structure of the pulsating flow generation unit 20 according to this embodiment will be described.
FIG. 2 is a cross-sectional view illustrating a cut surface obtained by cutting the pulsating flow generation unit according to the present embodiment along the fluid ejection direction. Note that FIG. 2 is a schematic diagram in which the vertical and horizontal scales of members or portions are different from actual ones for convenience of illustration. The pulsating flow generation unit 20 includes an inlet channel 81 that supplies a fluid from the pump 10 to the fluid chamber 80 via the fluid supply tube 4, a piezoelectric element 30 that serves as a volume changing unit that changes the volume of the fluid chamber 80, and the diaphragm 40. And an outlet channel 82 communicating with the fluid chamber 80. The fluid supply tube 4 is connected to the inlet channel 81.

  The diaphragm 40 is made of a disk-shaped thin metal plate and is in close contact with the case 50 and the case 70. In the present embodiment, the piezoelectric element 30 is an example of a laminated piezoelectric element, and one of both end portions is fixed to the diaphragm 40 via the upper plate 35 and the other is fixed to the bottom plate 60.

  The fluid chamber 80 is a space formed by a recess formed on the surface of the case 70 facing the diaphragm 40 and the diaphragm 40. An outlet channel 82 is opened at a substantially central portion of the fluid chamber 80.

  The case 70 and the case 50 are joined and integrated on opposite surfaces. In the case 70, a connection flow channel pipe 90 having a connection flow channel 91 communicating with the outlet flow channel 82 is fitted, and a nozzle 95 is inserted in the tip of the connection flow channel pipe 90. The nozzle 95 has a fluid ejection opening 96 having a reduced flow path diameter.

  Next, the pulse flow ejection operation of the pulsating flow generation unit 20 in this embodiment will be described with reference to FIGS. A fluid is supplied to the inlet channel 81 at a constant pressure by the pump 10. In addition, the fluid supply amount from the pump 10 may be an amount substantially equal to the pulse flow injection amount. Here, when the piezoelectric element 30 does not operate, the fluid flows into the fluid chamber 80 due to the difference between the discharge force of the pump 10 and the channel resistance on the entire inlet channel 81 side.

  When a drive signal is input to the piezoelectric element 30 and the piezoelectric element 30 suddenly expands in a direction perpendicular to the surface of the diaphragm 40 on the fluid chamber 80 side (arrow A direction), the volume of the fluid chamber 80 is reduced, and the fluid chamber 80 The internal pressure rises rapidly and reaches several tens of atmospheres.

  At this time, since the increase amount of the fluid discharged from the outlet channel 82 is larger than the decrease amount of the flow rate of the fluid flowing into the fluid chamber 80 from the inlet channel 81, a pulsating flow is generated in the connection channel 91. . The pressure fluctuation at the time of discharge propagates in the connection flow channel tube 90, and the fluid fluid pulsed from the fluid ejection opening 96 of the nozzle 95 at the tip is ejected at high speed.

Next, a case where tissue excision is performed using the fluid ejecting apparatus 1 will be described.
FIG. 3 is an explanatory view schematically showing a test method for excising gelatin as an alternative to living tissue. Here, the excision time and excision depth D were measured with the distance between gelatin 100 and the fluid ejection device (nozzle 95) constant in water.
FIG. 4 is a graph showing the relationship between the elapsed time from the start of excision (horizontal axis: s) and the excision depth D (vertical axis: mm) in the case of pulse flow and the case of continuous flow. In addition, the flow rate per unit time of the continuous flow inferior to the pulse flow was measured at 4 times the pulse flow.

  As shown in FIG. 4, in the pulse flow, the ablation proceeds rapidly immediately after the start of the ablation. Therefore, the excision depth D increases rapidly in a short time. When the excision depth D reaches a certain depth, the excision does not proceed. On the other hand, in the case of a continuous flow, the progress of excision is slow, and the excision depth D becomes deep with the elapsed time.

  Therefore, in the continuous flow, in order to make the excision depth constant, a high technique of making the moving speed in the plane direction of the nozzle 95 constant is required. When the movement is stopped, the excision depth advances, and the tissue to be left is excised. There is a danger of doing it. Therefore, the use of a pulse flow with very little change in the excision depth with the passage of the excision time is more effective for the excision of the tissue in the vicinity of the tubule tissue such as a blood vessel. In addition, since the ablation by the pulse flow depends on the ratio of the fluid ejection speed and the average flow velocity, this will be described.

Table 1 shows the diameter of the nozzle 95 (the diameter d of the fluid ejection opening 96: mm) and the average flow velocity V0 (m / m) for each nozzle diameter when the fluid supply amount from the pump 10 is 5 ml per minute. s), the pulsed fluid ejection speed V1 (m / s), and the ratio (V1 / V0) between the fluid ejection speed V1 and the average flow velocity V0.
The fluid ejection speed V1 is a result of measuring a pulsed fluid with a high-speed camera, and the average flow speed V0 is an order of the flow rate of the fluid supplied from the pump 10 by the cross-sectional area of the fluid ejection opening 96. This is the value obtained.

  As shown in Table 1, the average flow velocity V0 increases as the nozzle diameter d decreases, and the pulsed fluid ejection speed V1 also increases as the nozzle diameter d decreases. As a result, the ratio of the pulsed fluid jet velocity V1 to the average flow velocity V0 is 4.0 when the nozzle diameter d is 0.1 mm, and 4.6 when the nozzle diameter d is 0.12 mm. The ratio when the nozzle diameter d is 0.15 mm is represented by 6.4. This is because the flow path resistance component increases as the nozzle diameter d decreases, and the ratio between the pulsed fluid ejection speed V1 and the average flow speed V0 decreases.

Next, the relationship between the elapsed time (ms) from the start of excision and the excision depth D (mm) when gelatin described above is excised under the conditions of Table 1 (see FIG. 3) will be described.
FIG. 5 is a graph showing the relationship between the cutting time and the cutting depth for each nozzle diameter. As shown in FIG. 5, the cutting depth D becomes deeper as the nozzle diameter d increases, and the variation in the cutting depth D decreases from the vicinity where the elapsed time exceeds 20 ms for each nozzle diameter.

  Further, according to Table 1 and FIG. 5, when the ratio of the pulsed fluid ejection speed V1 to the average flow velocity V0 exceeds 4.0, that is, the pulsed fluid ejection speed V1 is four times the average flow velocity V0. It shows that the resection progresses rapidly in a larger area and reaches the asymptote of the resection depth D. This means that a constant excision depth can be maintained regardless of the moving speed of the fluid ejecting apparatus 1 (nozzle 95).

Here, the appropriate range of the ratio of the fluidized jet velocity V1 and the average flow velocity V0 will be further described. This will be described with reference to Table 2 and FIG.
Table 2 shows the nozzle diameter (diameter d of the fluid ejection opening 96: mm), the ratio between the pulsed fluid ejection speed V1 and the average flow velocity V0, and the fluid ejection under the conditions of Table 1 described above. The ratio of the excision depth D (mm) after 50 ms and the excision depth D (mm) after 100 ms, and the excision depth after each time (excision depth after 50 ms / 100 ms after Resection depth: In Table 2, expressed as a ratio). Reference is also made to FIG.

  As shown in Table 2, when the ratio between the fluid ejection speed V1 and the average flow velocity V0 is 4.0, the ratio of the excision depth is 88%, which is 90%. When the ratio between the fluid ejection speed V1 and the average flow velocity V0 is 4.6, the ratio of the cutting depth is 95%, and when the ratio between the fluid ejection speed V1 and the average flow velocity V0 is 6.4, The excision depth ratio is 94%. Therefore, when the ratio of the cutting depth is less than 90%, since the progress of the cutting depth with respect to the passage of time is large, a stable cutting depth cannot be expected, and when it is 90% or more, extremely high stability is obtained.

  Thus, by setting the fluid ejection speed V1 of the pulsed fluid to a speed exceeding 4 times the average flow velocity V0, the excision depth becomes substantially constant after a certain period of time while having excellent excision ability, Even if the operator does not keep moving the position of the fluid ejection opening at a constant speed, the excision depth variation is extremely small, eliminating the risk of damaging the tissue that should remain, regardless of the operator's procedure, The fluid ejecting apparatus 1 that can perform a safe operation can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Fluid injection apparatus, 10 ... Pump, 30 ... Piezoelectric element, 40 ... Diaphragm, 80 ... Fluid chamber, 81 ... Inlet flow path, 82 ... Outlet flow path, 96 ... Fluid injection opening part.

Claims (1)

A fluid chamber, an inlet channel and an outlet channel communicating with the fluid chamber, and a volume changing means for changing the volume of the fluid chamber;
A fluid ejection opening provided at an end in a direction opposite to the fluid chamber of the outlet channel;
A fluid supply unit that communicates with the inlet channel and supplies fluid to the fluid chamber;
Fluid ejection characterized in that the fluid ejection speed of the fluid pulsed by the volume changing means and ejected from the fluid ejection opening exceeds 4 times the average flow velocity of the fluid supplied from the fluid supply section apparatus.

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