HK1168522B - Ocular trocar assembly - Google Patents

Description

Ocular trocar assembly

Related patent application

This application claims priority to U.S. provisional application serial No. 61/151,426, filed on 10/2/2009, which is incorporated herein by reference in its entirety.

Background

The main difficulty in the treatment of ophthalmic diseases is to introduce drugs or therapeutic agents into the eye and to maintain these drugs or agents in therapeutically effective concentrations in the eye for the necessary time. Systemic administration may not be an ideal solution because unacceptably high levels of systemic administration are often required to achieve effective intraocular concentrations with an unacceptable increase in the incidence of adverse drug effects. Simple ocular instillation or administration is not a reasonable alternative in many cases, as the drug is quickly washed away by the tear action or from the eye into the systemic circulation. Suprachoroidal injections of drug solutions were also performed, but again the drug effectiveness was transient. Such methods make it difficult to maintain therapeutic levels of the drug for a sufficient period of time.

Attempts to solve this problem have led to the development of drug delivery devices or implants that can be implanted into the eye so that controlled amounts of the desired drug can be released continuously over a period of days, or weeks, or even months. Many such devices have been previously reported.

There are different sites in the eye for implantation of drug delivery devices or implants, such as the vitreous of the eye, the anterior or posterior chamber of the eye, or other regions of the eye, including the intraretinal, subretinal, intrachoroidal, suprachoroidal, intrascleral, scleral, subconjunctival, intracorneal, or supracorneal spaces. Regardless of the intended location of implantation, typical methods of implantation require relatively invasive surgical procedures, pose a risk of excessive trauma to the eye, and require excessive handling of the implant. For example, in one typical method for placement in the vitreous, an incision is made through the sclera and the implant is inserted and placed at the desired location in the vitreous using forceps or other similar manual grasping devices. Once placed, the forceps (or grasping device) are removed and the incision is sutured closed. Alternatively, an incision may be made through the sclera, a trocar may be advanced through the incision, and the implant may then be delivered through the trocar. Similar methods can be used to deliver implants to other locations, such as in the anterior chamber of the eye through an incision in the cornea.

The drawbacks of this type of implant delivery technique are numerous. There is a need in these techniques to over-treat the implant, with the risk that the implant will be damaged or contaminated during the procedure. Many such implants are polymer-based and relatively fragile. If portions of such implants are damaged and break, the release profile and/or effective therapeutic dose delivered by the implant once placed will be significantly altered. In addition, achieving repeatable placement between patients using these methods can be difficult. Also important is the fact that such techniques would require an opening in the sclera that is large enough to require sutures. Thus, such techniques are typically performed in a surgical environment.

An easier, convenient, less invasive, and/or less traumatic method for delivering an implant into an eye would be desirable.

Disclosure of Invention

The present invention provides methods and apparatus for delivering a payload into tissue, such as the eye.

In one aspect of the invention, a trocar assembly for delivering a payload into tissue is provided that includes a main housing, a cannula, a payload, an actuator, and a trocar. The cannula defines a lumen and has a proximal portion received in the housing and a distal portion extending from the housing. In certain embodiments, a payload is disposed in an initial position within the housing and in communication with the cannula. The trocar includes a distal end with a tip for piercing tissue and a proximal end in communication with a motive device for positioning the trocar, wherein in the extended position, the trocar occupies the lumen and extends through the distal end of the cannula, and wherein in the retracted position, the trocar is retracted from the lumen sufficiently that the payload can pass through the lumen to exit past the distal end of the cannula. The actuator advances the payload through the lumen to exit through the distal portion of the cannula.

In certain embodiments, the trocar is non-coring, e.g., does not define an open lumen, e.g., the trocar is solid and/or otherwise capable of substantially filling the lumen of the cannula. The trocar may comprise a metal, such as stainless steel. In certain embodiments, the trocar has a diameter of between 0.20mm and 0.75mm, such as about 0.5 mm. In some embodiments, the trocar may create about 20-to about 32-gauge (gauge) channels in tissue, such as 25-gauge channels in tissue.

In certain embodiments, the movement means for the trocar comprises a trigger mechanism that can be activated by a user to extend and retract the trocar. The assembly may further include a lock for locking the trocar in the retracted position.

In certain embodiments, the payload comprises a liquid. In certain embodiments, the payload may include a gas. In certain embodiments, the payload can include a solid, such as an ocular implant. The payload may include an agent (e.g., a drug or other therapeutic agent) and/or a diagnostic agent. In certain embodiments, the payload is located in a payload receptacle in the housing of the trocar assembly. In certain embodiments, the payload receptacle is removable from the housing. The payload container may be a cartridge or ampoule. The payload container may be disposable, refillable and/or sterilizable.

In certain embodiments, the cannula is coupled to the housing of the trocar assembly. The sleeve may comprise a metal, such as stainless steel, or a polymeric material, such as polyimide and/or polycarbonate.

The present invention also provides a method for delivering a payload into tissue, comprising: positioning the distal end of the cannula of the trocar assembly in contact with or adjacent to the tissue; inserting the trocar into the tissue; retracting the trocar; advancing the payload through the lumen; and indwelling the payload in the tissue. The trocar may be moved from the retracted position to the extended position prior to positioning the trocar within the tissue. In certain such embodiments, the trocar occupies the lumen and may extend through the distal end of the cannula in the extended position prior to positioning the trocar within the tissue. Once the trocar is positioned within the tissue, the distal end of the cannula remains within the tissue upon retraction of the trocar. The payload may then be advanced into the tissue by any means, such as a plunger, pump, vibration, or electrostatic gradient. In certain embodiments, wherein the payload is advanced by a plunger, the plunger may be actuated by any means, such as by a spring, compressed gas, or manual positioning.

Drawings

Figure 1 shows a trocar assembly 8 according to one embodiment of the present invention adjacent tissue 1 prior to insertion.

Figure 2 shows the trocar assembly 8 and trocar 2 inserted into the tissue 1 and the trocar 2 retracted, leaving the cannula 3 within the tissue 1.

Fig. 3 shows a payload 5 advanced from a payload container 4 through a cannula 3 and into tissue 1.

Fig. 4 shows: a. the cannula 3 of the trocar assembly 8 is inserted within the sclera of the eye 11 wherein the cannula 3 has an enlarged diameter portion 10 relative to the rest of the cannula 3 wherein b. the cannula 3 may be advanced into the eye tissue until the enlarged diameter portion 10 of the cannula meets the sclera 11 and obstructs further advancement of the cannula 3 into the eye.

Fig. 5 shows: a. the cannula 3 of the trocar assembly 8 is inserted within the sclera of the eye 11, wherein the cannula 3 has a constricted diameter portion 12 relative to the remainder of the cannula 3, wherein b. the cannula 3 may be advanced into the eye tissue until the constricted diameter portion 12 of the cannula meets the sclera 11 and obstructs further advancement into and/or retraction from the eye.

Detailed Description

One embodiment of the trocar assembly of the present invention is shown in figures 1-3. As shown, the trocar assembly 8 includes a main housing 6 with a cannula 3 and a trocar 2 extending outside the housing 6. The cannula 3 defines an internal lumen and has a proximal portion housed in the housing 6 and a distal portion protruding from the housing 6. The sleeve 3 may be integral with the housing 6 or separate from the housing 6. The trocar 2 comprises a distal end 20 with a tip for penetrating the tissue 1 and a proximal end 21 communicating with the moving means 7 for positioning the trocar 2, wherein in the extended position the trocar 2 occupies the lumen of the cannula 3 and extends through the distal end of the cannula 3, and wherein in the retracted position the trocar 2 is sufficiently retracted from the lumen such that the payload 5 can pass through the lumen to exit through the distal end of the cannula, e.g. into the tissue after retraction of the trocar. The payload 5 is stored in a payload receptacle 4, the payload receptacle 4 being connected to the housing 6 and/or being located partially or wholly within the housing 6.

In certain embodiments, the trocar 2 is moved from the retracted position to the extended position, as shown in figure 1, prior to insertion into the tissue 1. In some such embodiments, the trocar may extend through the distal end of the cannula in the extended position prior to insertion into tissue. In certain such embodiments, the trocar 2 and cannula 3 may be inserted into the tissue 1 by manual pressure in the manner of a needle of a syringe. In certain embodiments, the trocar 2 may be moved with the movement device 7 to access the tissue 1 by other means. In some such embodiments, the movement means 7 comprise a trigger mechanism that can be activated by the user for extending and retracting the trocar 2. After insertion of the cannula 3 into the tissue 1, the trigger mechanism may retract the trocar 2. The distal end of the cannula remains within the tissue upon retraction of the trocar. The trocar 2 may be extended, retracted, or both when the trigger mechanism is activated. In the retracted position, the trocar 2 may be locked in place by a lock 9. The trigger mechanism may work in conjunction with the lock 9 such that when the trigger mechanism is activated, the lock 9 is released and the trocar 2 is extended. In the particular embodiment in which the trigger mechanism activates the trocar 2 to extend and retract, the trigger mechanism may release the lock 9 prior to extending the trocar 9 and lock the trocar 2 in place once the trocar 2 is retracted again. The moving means 7 may be activated by any known method for advancing an object through tissue. Exemplary methods for activating the movement means 7 include springs, compressed gas or mechanical gears.

With the trocar 2 in the retracted position, as shown in figure 2, and the cannula 3 within the tissue 1, the payload 5 may be advanced by the actuator through the lumen to exit through the distal portion of the cannula 3. The payload 5 may be propelled by any known method for advancing a solid, liquid or gas through the casing 3. The payload 5 may be advanced from the payload receptacle 4 with an actuator, such as a plunger, pump, vibration, or electrostatic gradient. In certain embodiments, wherein the actuator is a plunger, the plunger is activated with any one of a spring, compressed gas, or manual compression.

To use the trocar assembly to deliver a payload into tissue of a patient, the trocar assembly is positioned near the desired point of entry into the tissue. The trocar assembly may be mounted on a stand and/or supported by a user's hand. The patient will typically be under topical or local anesthesia. The user may then advance the trocar into the tissue and position the cannula at a desired location within the patient's tissue for payload storage. Once the cannula is positioned, the user may push the actuator to deliver the payload from the payload receptacle through the lumen and out the distal end of the cannula. After delivery of the payload is complete, the cannula is withdrawn from the patient's tissue.

In one exemplary embodiment, a trocar assembly is used to deliver a payload into an eye. The trocar assembly may be used to position the payload at the intended implantation location, such as in the vitreous cavity of the eye. For such embodiments, the trocar assembly may be positioned adjacent the eye with the trocar extending through the sclera and into the vitreous of the eye. The sleeve may be positioned at a desired location in the vitreous of the eye for payload placement. Once the payload is delivered into the eye, the cannula may be retracted.

In certain embodiments, the payload comprises a liquid and/or a gas. The payload may comprise a solid, such as an ocular implant, such as a drug delivery device. Such devices can generally be implanted at any number of locations in tissue and can be designed so that a controlled amount of the desired drug or therapeutic agent can be released over time. The payload may include a pharmaceutical agent. In certain embodiments, the payload is a micro-implant that includes a therapeutic agent and a polymer. The microimplants may be delivered through a cannula corresponding to a 21-gauge cannula or smaller and thus have a cross-sectional diameter of 0.66mm or less. Methods for manufacturing microimplants include extrusion, injection molding, compression molding, and tableting. In certain embodiments, the payload is located in a payload receptacle in the housing of the trocar assembly. In some embodiments, the payload receptacle is removable from the housing. The payload container may be a cartridge or ampoule. The payload container may be disposable, refillable and/or sterilizable.

In certain embodiments, the trocar is non-coring, e.g., the trocar does not include a lumen. The trocar may comprise a metal, such as stainless steel. In certain embodiments, the trocar has a diameter of between 0.20mm and 0.75mm, such as about 0.75mm, about 0.60mm, about 0.50mm, about 0.40mm, about 0.30mm, or about 0.20 mm. In some embodiments, the trocar may create a channel in tissue of about 16-to about 32-gauge, such as about 25-gauge, about 26-gauge, about 27-gauge, about 28-gauge, about 29-gauge, or about 30-gauge, in tissue.

A typical problem when inserting a trocar with a lumen into any tissue is the "coring" of the tissue, where the insertion actually cuts a cylindrical section of tissue that enters the trocar lumen. When such coring occurs in the eye, coring can exacerbate leakage of ocular fluid through the injection site. An alternative is to use a non-coring trocar, such as a solid or partially solid trocar, so that the tip of the trocar does not include an opening. In such embodiments, the proximal end of the trocar may include a sharp or blunt tip. Other conventional methods known in the art for avoiding coring may be used, such as deflecting the tip of the trocar or dulling and sharpening portions of the trocar point.

In certain embodiments, the cannula is coupled to the housing of the trocar assembly. The cannula may comprise a metal, such as stainless steel, or a polymeric material, such as polyimide, silicone, polycarbonate, and/or polyvinyl carbonate. In certain embodiments, the sleeves to be used in the present invention are thin walled. The cannula has an outer diameter of between 0.25mm and 1.0mm, such as about 1.0mm, about 0.90mm, about 0.80mm, about 0.70mm, about 0.60mm, about 0.50mm, about 0.40mm, about 0.30mm or thereabouts, or about 0.25 mm. In some embodiments, the cannula may remain open to about 16-to about 32-gauge passage in tissue, such as about 21-to about 30-gauge passage in tissue, such as about 24-gauge, about 25-gauge, about 26-gauge, about 27-gauge, about 28-gauge, about 29-gauge, or about 30-gauge passage in tissue.

The cannula of the present invention may have a uniform outer diameter, or the diameter may vary along the length of the cannula. For example, as in fig. 4a, the cannula 3 may have an enlarged diameter portion 10 relative to the rest of the cannula 3, and in b the cannula 3 may be advanced into eye tissue until the enlarged diameter portion 10 of the cannula encounters the sclera 11 and obstructs further advancement of the cannula 3 into the eye (fig. 4). In other exemplary embodiments, such as in fig. 5a, the cannula 3 has a constricted diameter portion 12 relative to the rest of the cannula 3, and in b the cannula 3 may be advanced into eye tissue until the constricted diameter portion 12 of the cannula meets the sclera 11 and obstructs further entry into and/or withdrawal from the eye (fig. 5). In certain such embodiments, the enlarged diameter portion 10 and/or the reduced diameter portion 12 of the cannula 3 can correspond to a predetermined depth into tissue and/or a desired depth of implantation.

The present invention also contemplates the use of cannulas having non-circular cross-sections, including oval or elliptical cross-sections. For such non-circular cross-section cannulas, it is desirable that the cross-sectional area corresponds to the cross-sectional area of a circular cannula having a diameter of up to 1.0 mm.

In certain embodiments, the cannula is designed to limit the introduction of air into the eye when injecting the implant. In one exemplary embodiment, the implant may be positioned proximally to the trocar point, but with sufficient tolerance between the implant and the cannula wall to provide venting past the implant as the implant moves through the cannula.

The payload may then be advanced into the tissue by any means, such as a plunger, pump, vibration, or electrostatic gradient. In certain embodiments, wherein the payload is advanced by a plunger, the plunger may be actuated by any means, such as by a spring, compressed air, or manual compression.

Additional embodiments provide safety features including, among other features, a locking mechanism to prevent reuse of the applicator, a gauge to determine the proximal position of a cannula within tissue, and a pressure gauge to monitor pressure increases within tissue (e.g., an eye).

In addition to delivering implants into the eye, devices as disclosed herein can be used to inject implants into other tissues, and are particularly useful where minimal tissue damage is required (e.g., implantation of cerebrospinal fluid, bladder, etc.).

Equivalent replacement

Further, the present invention provides trocar assemblies and methods of use thereof. While specific embodiments of the subject invention have been discussed, the foregoing description is illustrative and not restrictive. Many variations of the invention will become apparent to those of ordinary skill in the art upon reading this specification. The full scope of the invention should be determined by reference to the claims, along with their full scope of equivalents, and the specification, along with such modifications.

Incorporation by reference

All publications and patents mentioned herein are incorporated by reference in their entirety to the same extent as if each individual publication or patent was specifically and individually indicated to be incorporated by reference. In the event of conflict, the present application, including any definitions herein, will control.

Claims (23)

1. A trocar assembly for delivering a payload into tissue, comprising:

a main housing;

a cannula defining a lumen and having a proximal portion received in the housing and a distal portion extending from the housing;

a solid payload disposed in an initial position within the housing and in communication with the casing;

an actuator for advancing the solid payload through the lumen to exit through the distal portion of the cannula;

a trocar including a distal end with a tip for piercing tissue and a proximal end in communication with a motive device for positioning the trocar, wherein in an extended position, the trocar occupies the lumen and extends through the distal end of the cannula, and wherein in a retracted position, the trocar is retracted from the lumen sufficiently that the solid payload can pass through the lumen to exit past the distal end of the cannula.

2. The assembly of claim 1, wherein the trocar is non-coring.

3. The assembly of claim 1, wherein the trocar comprises metal.

4. The assembly of claim 3, wherein the trocar comprises stainless steel.

5. The assembly of any of claims 1-4, wherein the movement means comprises a trigger mechanism actuatable by a user for extending and retracting the trocar.

6. The assembly of claim 1, further comprising a lock for locking the trocar in the retracted position.

7. The assembly of any one of claims 1-4 and 6, wherein the solid payload comprises a pharmaceutical agent.

8. The assembly of claim 1, wherein the trocar is between 0.20mm and 0.75mm in diameter.

9. The assembly of claim 8, wherein the trocar is about 0.5mm in diameter.

10. The assembly of any of claims 1-4, 6, 8, and 9, wherein the trocar creates a 16-gauge to 32-gauge channel in the tissue.

11. The assembly of claim 10, wherein the trocar creates a 25-gauge channel in the tissue.

12. The assembly of claim 1, wherein the sleeve comprises a metal.

13. The assembly of claim 12, wherein the sleeve comprises stainless steel.

14. The assembly of claim 1, wherein the sleeve comprises a polymeric material.

15. The assembly of claim 14, wherein the sleeve comprises polyimide and/or polycarbonate.

16. The assembly of claim 1, wherein the solid payload is located in a payload receptacle in the housing.

17. The assembly of claim 16, wherein the payload receptacle is removable from the housing.

18. The assembly of claim 17, wherein the payload container is a cartridge or ampoule.

19. The assembly of claim 18, wherein the payload container is a single-use container.

20. The assembly of claim 18, wherein the payload receptacle is refillable.

21. The assembly of claim 18, wherein the payload container is sterilizable.

22. The assembly of any of claims 1-4, 6, 8-9, and 12-21, wherein the tissue comprises an eye.

23. The assembly of claim 22, wherein the solid payload comprises an ocular implant.