Surgery – Means for introducing or removing material from body for... – Material introduced into and removed from body through...
Reexamination Certificate
2000-12-21
2004-04-20
Hayes, Michael J. (Department: 3763)
Surgery
Means for introducing or removing material from body for...
Material introduced into and removed from body through...
C604S027000, C604S035000, C604S045000, C604S048000, C606S107000, C606S166000
Reexamination Certificate
active
06723065
ABSTRACT:
BACKGROUND OF THE INVENTION
This application claims the priority of JP 11-364413, file Dec. 22, 1999, the disclosure of which is expressly incorporated by reference herein.
1. Field of the Invention
The present invention relates to an intraocular surgical apparatus for use in a surgical operation for treating, e.g., cataract.
2. Description of the Related Art
In recent years, for treatment of eye diseases such as cataract, a surgical operation is often carried out to replace the affected crystalline lens in the eye of the subject with an intraocular lens (artificial crystalline lens). In this respect, as an operation for extirpating such an affected part as the crystalline lens, there is known the ultrasonic emulsifying aspirating operation (KPE) for applying ultrasonic waves to the affected part, e.g., crystalline lens, for pulverizing (emulsifying) the part and simultaneously aspirating and discharging the pulverized part to the outside.
A typical apparatus for use in such an ultrasonic emulsifying aspirating operation is shown in FIG.
4
. The apparatus includes a handpiece
3
having an introduction tube
1
for introducing perfusate (artificial aqueous humor) C into the closed intraocular affected part B and a discharge tube
2
for discharging the emulsified affected part together with the perfusate C. A perfusate feed passage D connected to the introduction tube
1
incorporates a perfusate reservoir E capable of feeding the perfusate C with a predetermined rest liquid head pressure (h). A discharge passage G connected to the discharge tube
2
of the handpiece
3
incorporates a suction pump H for controlling the operation of a switch valve F of the feed passage D to open the valve F in association with an aspirating operation or to close it in association with stopping of the aspirating operation.
When operating an apparatus constructed as described above, an outlet opening
1
B of the introduction tube
1
and an aspiration opening
2
A of the discharge tube
2
of the handpiece
3
are inserted together into the closed intraocular affected part B through a small access incision made in the cornea or sclera of the eye to be treated.
Then, ultrasonic waves are applied to the affected part, such as a crystalline lens, for gradual emulsification. At the same time the emulsified part is aspirated and discharged to the outside by the suction force of the suction pump H. During this step, the switch valve F incorporated in the perfusate feed passage D is opened in response to the operation of the suction pump H. Open switch valve F allows the introduction, in association with the sucking action of the pump, of fresh perfusate C into the intraocular affected part B via the introduction tube
1
. The amount of fresh perfusate C introduced into the intraocular affected part B corresponds to the amount of material aspirated and discharged from the perfusate reservoir E. This balances the flow rate of perfusate and the suction force of the suction pump.
However, as illustrated in
FIG. 5
, it sometimes happens that the introduced part may be momentarily stuck at the aspiration opening
2
A of the discharge tube
2
and then suddenly released therefrom to be drawn toward the discharging side. In the case of such an excessive aspiration phenomenon, because the perfusate feed passage D provides certain passage resistance and the outflow rate of the perfusate C from the outlet opening
1
B of the introduction tube
1
is fixedly governed by the effect of free-fall, the balance between the inflow amount from the introduction tube
1
and the outflow or discharge amount from the discharge tube
2
is lost, with the latter exceeding the former. This leads to momentary abnormal pressure reduction and development of negative pressure within the closed intraocular affected part B compared with a normal pressure in the case of a normal operation. The negative pressure may result in a so-called micro-collapse phenomenon characterized by reduction in the content volume of the eyeball and the anterior chamber. In an extreme case, such a micro-collapse phenomenon may result in rupture of the posterior capsule or damage in the endothelium camerae anterioris.
Customarily, when a surgeon notices the possibility of such a phenomenon, the surgeon will expediently adjust the amount of ultrasonic waves and/or the aspiration amount in such a manner as to avoid it. However, in order for the surgeon to be able to do so, they need a good amount of practice with animal or artificial eyes for training as well as a considerable amount of actual experience in the surgery.
SUMMARY OF THE INVENTION
The present invention pertains to the above-described state of the art. The primary object of the invention is to provide an improved intraocular surgical apparatus which effectively prevents occurrence of the micro-collapse phenomenon in the eyeball and the anterior chamber in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part at, e.g., the inlet opening of the discharge tube and subsequent sudden movement thereof toward the discharging side.
For fulfilling the above-noted object, according to one aspect of the present invention, an intraocular surgical apparatus is provided, comprising:
an introduction tube for introducing perfusate into a closed intraocular affected part;
a discharge tube for discharging the affected part together with the perfusate;
a perfusate feed passage connected to the introduction tube, the perfusate feed passage incorporating a perfusate reservoir capable of feeding the perfusate with a predetermined rest liquid head pressure, and a control valve for controlling the amount of perfusate to be fed from the perfusate reservoir to the introduction tube; and
a discharge passage connected to the discharge tube, the discharge passage incorporating a suction pump;
wherein the perfusate feed passage further incorporates, at a passage portion thereof from the control valve to an outlet opening of the introduction tube, a pressure-reduction compensating means capable of feeding a supplementary amount of perfusate into the closed intraocular affected part through a supplementing passage having a smaller passage resistance than the perfusate feed passage in the event of and in association with abnormal pressure reduction inside the affected part.
With the above-described construction, in the event of abnormal pressure reduction in the closed intraocular affected part due to momentary clogging of the affected part (at, e.g., the inlet opening of the discharge tube) and subsequent sudden release and movement thereof toward the discharging side, in operative association with this pressure reduction, the pressure-reduction compensating means can supply, through the supplementing passage, a supplementary amount of perfusate to the affected part in order to compensate for the pressure reduction. Accordingly, occurrence of micro-collapse in the eyeball and the anterior chamber can be effectively prevented, so that the surgical operation may take place in a safe and reliable manner.
In the above construction, the pressure-reduction compensating means is provided midway to the perfusate feed passage. Since the passage resistance becomes smaller closer to the inlet opening of the discharge tube, it is preferred that the pressure-reduction compensating means be provided at a position near the inlet opening of the discharge tube. It is also to be noted that the control valve incorporated within the perfusate feed passage can be a variable-flow control valve instead of a switch valve.
According to one preferred embodiment of the present invention, the pressure-reduction compensating means includes a supplementary perfusate reservoir storing a portion of the perfusate flowing within the perfusate feed passage and acting as a supplementing passage, and a gas reservoir for reserving gas compressed under the predetermined rest liquid head pressure of the perfusate reservoir. With this construction, in the event of abnormal pressure reductio
Crowell & Moring LLP
Ghafoorian Roz
Hayes Michael J.
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