BACKGROUND

The present disclosure relates to systems and methods for penetration devices used in medical applications. More particularly, the present disclosure provides systems and methods to improve the positional accuracy of penetration devices and, specifically, penetration devices relating to cavities.

Penetration devices such as needles are often used to inject or drain cavities. Issues arise when the individual using the needle is unable to confirm the needle's entrance into a cavity. This type of blind insertion can result in a procedure that is only partially successful, or even a failed procedure.

Current cavity sensing needles are only useful in certain procedures, as they are typically one size per needle. Current solutions also lack the sensitivity necessary for substantially small cavities. One example of such a cavity is the suprachoroidal space, located between the sclera and the choroid within the eye.

The suprachoroidal space has been explored as a potential site for drug delivery to target the back of the eye. This region of the eye, called the posterior segment, has several associated diseases that benefit from drug treatment. Drug delivery via the suprachoroidal space has been shown to be more effective than direct intravitreal injections to the posterior segment. However, determining needle entrance to the suprachoroidal space is both critical to the success of the drug treatment, as well as very difficult to achieve.

Current cavity sensing needles are too large for optical use, and lack the sensitivity necessary to detect the suprachoroidal space.

A system and method for a penetration device that has improved sensitivity and positional accuracy is therefore desired.

SUMMARY

The present disclosure provide a penetration device that employs a new self-regulatory design, via resistance, to achieve accurate penetration device placement. The new penetration device can be particularly accurate when employed relative to a cavity, and can achieve higher performance than conventional penetration devices and methods.

In accordance with one aspect of the present disclosure, a system for delivering an injection of a fluid to a void within a subject is described. The system includes a syringe barrel extending from a first end to a second end and forming a lumen extending from the first end to the second end. The system further includes a plug arranged within the lumen proximate to the first end. The plug forms a seal between the plug and the syringe barrel against fluid movement from the lumen between the plug and the syringe barrel. The system additionally includes a floating seal arranged within the lumen proximate to the second end forming a seal between the floating seal and the syringe barrel against fluid movement from the lumen between the floating seal and the syringe barrel. The system further includes a hollow needle extending from a proximal end connected to the floating seal to a distal end having an opening formed at the distal end for fluid to flow from the lumen, through the floating seal, and through the second end of the syringe barrel via the hollow needle. The syringe barrel, the plug, and the floating seal include material and dimensions selected based on a threshold flowrate for a fluid arranged within the lumen. The threshold flowrate of the fluid is used to, upon applying a force or pressure to the fluid, overcome an opposing force so that the floating seal and hollow needle move from the second end of the syringe barrel and the distal end of the hollow needle extends into a tissue of the subject. The threshold flowrate of the fluid is further used to, upon the distal end of the hollow needle extending beyond the tissue of the subject and into a void, succumb to the opposing force to displace the fluid through the opening formed at the distal end of the hollow needle into the void.

In accordance with one aspect of the present disclosure, a method for delivering an injection of a fluid to a void within a subject is described. The method includes providing a syringe system including: a syringe barrel extending from a first end to a second end and forming a lumen extending from the first end to the second end, a plug arranged within the lumen proximate to the first end and forming a seal between the plug and the syringe barrel against fluid movement from the lumen between the plug and the syringe barrel, a floating seal arranged within the lumen proximate to the second end forming a seal between the floating seal and the syringe barrel against fluid movement from the lumen between the floating seal and the syringe barrel, and a hollow needle extending from a proximal end connected to the floating seal to a distal end having an opening formed at the distal end for fluid to flow from the lumen, through the floating seal, and through the second end of the syringe barrel via the hollow needle. The method further includes arranging the distal end of the hollow needle to extend into the tissue without applying a force to the fluid. The method additionally includes applying a force to the fluid to overcome an opposing force to move the floating seal and hollow needle from the second end of the syringe barrel and extend the distal end of the hollow needle further into the tissue of the subject. The method further includes continuing said applying the force to the fluid as the distal end of the hollow needle extends beyond the tissue of the subject and into the void as the floating seal succumbs to the opposing force between the floating seal and the syringe barrel to displace the fluid through the opening formed at the distal end of the hollow needle into the void.

The foregoing and other advantages of the present disclosure will appear from the following description. In the description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration a preferred embodiment of the disclosure. Such embodiment does not necessarily represent the full scope of the disclosure, however, and reference is made therefore to the claims and herein for interpreting the scope of the disclosure.

