The present application is directed to a hand-operated (i.e., manual) intraocular fluid delivery device.
Minimally invasive surgical procedures involving ocular incisions and/or intraocular fluid injection can be useful for treating glaucoma and other eye conditions. For example, in a Trabeculectomy, a surgeon can use an ophthalmic blade inserted through an incision in the eye to remove a portion of the trabecular meshwork, thereby improving outflow of the aqueous humour (AH) and relieving intraocular pressure contributing to glaucoma.
During the removal of the trabecular meshwork using an ophthalmic blade, some cases have been observed in which minor bleeding occurs. When bleeding occurs during the surgery, the blood can cover up the trabecular meshwork and Schlemm's canal, creating a visual obstruction. One method of dealing with the blood reflux involves removing the ophthalmic blade from the eye and inserting a viscoelastic syringe. The viscoelastic syringe can be used to push viscoelastic into Schlemm's canal and/or into the collecting channels or move the blood away from the trabecular meshwork. Once the blood is pushed away from the trabecular meshwork, the viscoelastic syringe is removed from the eye and ophthalmic blade is re-inserted to continue the surgery.
With ophthalmic surgeries and drug deliveries in the eye, there is a need for extreme delicacy and precision by the doctor. Any advantage that a medical device can offer in terms of useability, control and precision of movements has a significant impact on surgical outcomes. Using a syringe to dispense fluid in these procedures is proving inadequate and many doctors and medical device companies have tried to find alternate means.
This application presents fluid delivery devices and methods for the treatment of ocular disorders requiring targeted and controlled administration of a fluid into the eye for reduction or prevention of symptoms of the disorder.
A fluid injection device can include a surgical instrument coupled to the distal end for an ophthalmic procedure and can have a lumen configured to convey the substance into an intraocular site of a patient. A fluid compartment can be internal to the device or coupled to the device and configured to hold a substance.
Current fluid injection devices have drawbacks including entrapping air in the system, fluid seeping which leads to unintentional discharge, and inadequacy dealing with the high pressures often experienced. A commonly used fluid in ophthalmic surgeries, viscoelastic, is nonnewtonian and extremely viscous. The characteristics of viscoelastic when used through a reciprocating pump are the cause of poor performance in both device output, as well as the high user force required to dispense fluid. A peristaltic design pump, or externally deforming and advancing fluid through a flexible tube, is superior for dispensing these types of fluids. The fluid path can be a continuous flexible tube which eliminates air entrapment and is better for advancing even the most viscous fluids through the system.
A peristaltic pump system contained in a handheld device can provide the control and precision the doctor requires without the performance limitations of alternative pump systems.
Alternatively, a rotary pump mechanism in the device can be configured to transfer fluid about its axis to draw the substance from the fluid compartment and eject the substance through the lumen/flexible tubing of the tool. One benefit of a rotary pump, like a peristaltic pump, is that fluid can be drawn out of a reservoir. This reservoir can be an internal chamber, or an externally attached chamber, such as a syringe.
Pressing the handle of the pump causes the mechanism to rotate, causing the rollers to crush/squeeze the tubing (Durometer Shore80A or less) which moves the fluid though the tubing and into the cannula to be delivered to the patient. Upon initial use, the handle should be pressed enough times so that fluid is dispensed from the distal end prior to use on the patient.
No part of the mechanism makes contact with the fluid itself. Theoretically, this device could achieve the lowest biocompatibility risk of any ophthalmic pump since the fluid only needs to contact the lumen/flexible tubing and the cannula. However, more components may be necessary in the fluid path for the tubing-to-cannula connection and the tubing-to-fluid compartment connection.
A ratchet, clutch, and one-way bearing may be utilized to prevent the mechanism from reversing direction which reduces risk to the patient. The nature of a manually powered rotary pump also lowers the risk of delivering excess fluid to the patient because there is little pressure buildup within the fluid as compared with other standard fluid pumps.
A push button can be on the side of the housing and configured to engage the rotary pump to actuate a forward fluid flow towards the distal end of the device.
Stored Energy
With a direct drive design, as the handle is depressed the peristaltic pump, which is directly linked, moves a corresponding amount. The speed and length of handle depression directly correlates to fluid output.
With a stored energy design, there is a kinetic force driving the pump. When depressing the handle, it acts as a trigger to release a catch and expend some of the kinetic energy to independently rotate the pump.
Stored energy in the form of a spring can come from a wound clock spring supplying a rotary force to the pump. Stored energy in the form of a spring can also come from a linear spring exerting force on a rack which turns a pinion to supply rotary force to the pump. These stored energy methods can come preloaded or can be loaded by the end user. An example of this would be the user winding up the clock spring or “cocking” the linear spring.
The catch mechanism could be preset or configurable by the user. This catch mechanism would allow escapement of the rotary pump while it has a rotary force applied on it. An example of this type of escapement mechanism with a rotary force applied to it is a clock. In this pump mechanism, a gear with set tooth spacing can dictate the amount of rotation per handle depression. This would allow the user to dispense a set amount of fluid with each handle depression.
This method of stored energy to drive the pump will allow a shorter handle motion along with less force. This is critical for device stability and accuracy when dispensing fluid into the eye.
While the catch mechanism is ideal for dispensing a set amount of fluid, sometimes a continuous flow is desired. When a surgeon uses a syringe to inject fluid, they often dose according to visual feedback. For example, when filling the eye with viscoelastic, they would supply enough fluid to displace all present eye fluid, remove bubbles and hold the shape of the anterior chamber based off their visual feedback.
In place of a catch mechanism, a braking mechanism can be used to supply continuous flow. When the handle is depressed, the brake is released, allowing the pump to rotate. A braking mechanism could directly constrain the axis of rotation of the pump, or it can engage the moving rack. The fluid flow path after the pump could also be pinched or contain an open/shut valve that the handle controls.
In this design, dampening can be used to set the fluid flow velocity. Dampening will allow the pump to spin at a set speed when released, rather than spin uncontrolled until the stored energy is exhausted. The mechanical drive can be dampened directly or the fluid outflow can be constricted to limit fluid flow exiting the device. An example of controlling the fluid flow rate directly would be a valve that the user can adjust to get the desired flow rate.
CO2 Design
Another variation of the rack and pinion method to supply rotational force, would be to replace the linear spring with a piston driven by compressed gas. An example of a compressed gas would be a CO2 cartridge that is already commonly sold.
CO2 cartridges are currently used to power a number of mechanical devices. Some examples include parachute deployment devices, air powered rifles, and intraocular lens deployment devices. In these cases, the gas excerpts a force on a mechanical element. With a CO2 cartridge, the CO2 is a liquid while in its container. As the liquid CO2 enters a larger space, such as a cylinder, it turns to gas. While in the expansion phase from liquid to gas, the pressure exerted from the CO2 is very constant. This constant force can be applied to a piston, so that over the length of the stroke of the piston, the force applied to the piston is very constant. A CO2 driven piston driving a rack would have a more uniform force over the length of travel as compared to a spring driving a rack, since the spring force decreases as the spring approaches relaxed length.
Turbo Design
Another method of supplying rotary force to the peristaltic pump with CO2 is to use a turbocharger like design. In this design, there is a turbine section that is connected mechanically, such as a shaft, to the rotary pump. As the CO2 passes through the turbine or impeller section, it will cause this impeller to rotate and in turn drive the rotary pump that it is coupled to. This design can accommodate both the catch mechanism or braking mechanism to control the fluid outflow.
Activating the CO2 Cartridge
With a CO2 powered device, the user could activate or charge the device by penetrating the cartridge. As with current CO2 devices on the market, this activation could be accomplished by a twisting, pressing or lever mechanism by the user.
Electric Motor Drive
Another method of supplying rotary force to the peristaltic pump is with an electric motor. The most widely available industrial peristaltic pumps are commonly driven by an electric motor. In these commercially available designs, the operator either loads tubing into the pump body or connects tubing to inlet and outlet ports on the pump. These pumps are usually large and made to sit on a desk, or be attached to a power tool.
In this design, the peristaltic pump and driving motor are both be scaled down to fit inside of a handset for ophthalmic use. The motor could be driven by an onboard power source or coupled to external power. Internalizing these components limits the tubing running out of the device and allows for freedom of movement. It also eliminates the large pump unit that would have to sit in the operating room and possibly inside of the sterile field. By eliminating the external pump unit, the length of travel for the ophthalmic fluid is decreased and therefore reduces waste. Ophthalmic fluid, such as viscoelastic, can be very expensive and often only sold in small vials.
A motor driven pump allows the use of electrical controls which can be set by the user to dictate the fluid output. The user can select a specific dosage per handle depression or select a continuous flow with adjustable flow rate.
Features and advantages of the present invention will become appreciated as the same become better understood with reference to the specification, claims, and appended drawings wherein:
The present application provides fluid delivery devices and methods for the treatment of ocular disorders requiring targeted and controlled administration of a fluid to an interior portion of the eye for reduction or prevention of symptoms of the disorder. Applications may include: injecting viscoelastic into the SC, injecting mitomycin under the conjunctiva, and medicine delivery via intravitreal injection.
The device 20 has an outer housing 22 with a proximal luer fitting 24 and a distal surgical instrument 26. The instrument 26 may be a needle, a bent or straight tube, or another specially designed part to interface with selected tissue. In the illustrated embodiment, the instrument 26 is a straight cannula having a distal tip adapted for insertion into an intraocular space in an eye. The device 20 further includes an actuator 30 for advancing fluid in a proximal-distal direction through the device.
Flexible inlet tubing 50 connects to a fluid inlet 52 defined by the proximal luer fitting 24 and extends to the chamber 34. Flexible outlet tubing 54 connects to a fluid outlet 56 defined by a proximal end of cannula 26 and extends to the chamber 34. The inlet tubing 50 and outlet tubing 54 in the illustrated embodiment are contiguous and define a helical loop 58 around the inner wall 36 of the chamber 34.
In the embodiment of
In the embodiment of
Aspects of the present application may include:
Fluid drawn from internal or external reservoir.
Fluid enters eye through a body that penetrates the cornea/sclera and delivers fluid:
Fluid may be transferred by a pump that works by splitting the fluid into segments and then driving those segments forward in a rotary fashion.
The application also discloses a rotary pump mechanism configured to drive fluid in one direction with the aid of a ratchet, clutch, and one-way bearing.
The rotation of the pump will be controlled and mechanically driven via a manually operated arm/lever.
The practitioner will interface with this arm directly to drive the pump. The actuation of this arm is to be of a size, force and movement such that it may be operable with a finger while holding the device.
While the invention has been described in its preferred embodiments, it is to be understood that the words which have been used are words of description and not of limitation. Therefore, changes may be made within the appended claims without departing from the true scope of the invention.
The present application claims priority to prior U.S. provisional Ser. No. 63/417,633, filed Oct. 19, 2022.
Number | Date | Country | |
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20240130852 A1 | Apr 2024 | US |
Number | Date | Country | |
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63417633 | Oct 2022 | US |