While most medical tools have seen incredible advances over the past century, the syringe has remained relatively unchanged despite room for improvement. Without the use of live imaging or sensing systems, which require additional time and resources, nurses and physicians must rely on blind insertion techniques using superficial anatomical landmarks, fluid return, and tactile feedback to accurately deliver a syringe’s contents. These techniques can be problematic when targeting smaller areas, or regions where overshoot can result in harm to the patient. One such region is the suprachoroidal space, located between the sclera and chorois, which is less than 1 mm thick and where overshoot can cause damage to the retina. Other common tissue targets include the epidural space around the spinal cord, the peritoneal space in the abdomen, and subcutaneous tissue between the skin and muscles.
To address this issue, investigators at Harvard’s Brigham and Women’s Hospital have designed a new form of mechanical injector, the I2T2, which detects changes in resistance to safely deliver injections. In the design, the operator simply pushes the plunger, and the device can sense the loss of resistance at which time it stops advancing the needle and delivers the payload. The I2T2 works by mounting the needle on a sliding support, allowing it to move along the syringe barrel, and enabling pressure to build on the internal fluid. Once the needle encounters the targeted cavity space, the reduced resistance allows the fluid to be immediately released, which stops the needle from moving any further.
In testing on an animal model of the suprachoroidal space, the device was demonstrated to have reliable injection accuracy without any additional training or reliance on specialized techniques. Because this is a platform technology, the investigators believe that the uses of the I2T2 are widespread, and that design criteria can be adjusted to meet the needs of each implementation. The next steps towards use in humans involve proof of safety and utility in pre-clinical disease models.
Study in Nature Biomedical Engineering: A resistance-sensing mechanical injector for the precise delivery of liquids to target tissue…
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