What it does
Cautris is an endoscope-guided chemical cautery device that replaces traditional sticks, enabling precise silver nitrate delivery to treat both anterior and posterior nosebleeds safely and effectively, reducing risk, cost and time in epistaxis management.
Your inspiration
Initially tasked with improving the simple silver nitrate stick, we discovered its limitations — risk of burns, restricted use in anterior nosebleeds and reliance on ENT expertise. Electrocautery, while an alternative, is costly, time-consuming, and resource-heavy. Inspired to develop a safer, more efficient solution, we designed Cautris — a reusable, endoscope-compatible device with a disposable silver nitrate tip and a pulley-based control system. The mechanism derived from a curtain system and endcaps of a bicycle's brake cables, forming a fusion of the two sparked from a casual discussion of the blinds in the office.
How it works
Cautris is a chemical cauterisation device consisting of two parts: a disposable articulation sleeve and a reusable metal main body with ergonomic controls. It features a 2 mm silver nitrate tip housed in the disposable TPU sleeve which bends via two 0.1 mm nitinol wires embedded in its walls and connects to the main body through small nubs, allowing easy replacement for hygiene in busy clinics. The metal main body offers stability and ease of use with a gun-like grip, requiring minimal training. It includes three key controls: a thumb-operated scroller that pulls the nitinol wires to articulate the tip from -30° to +30° via a pulley system; an index finger slider that sheaths or extends the silver nitrate tip up to 4 mm; and a gear scroller that rotates the tip, exposing unused areas to maintain effectiveness without replacement. Together, these controls enable 360° coverage of the nasal cavity when combined with wrist rotation.
Design process
The 13-week project began with research and observation at an ENT clinic and anatomy simulator, revealing pain points in current silver nitrate sticks and electrocautery — poor ergonomics, limited control, and chemical safety risks. Early low-fidelity prototypes made from foam and cardboard explored grip and actuation, tested on a 3D-printed TPU nose by clinicians who provided key feedback. Progressing to CAD design and 3D printing, mid-fidelity prototypes refined fit, assembly, and actuator mechanisms. ENT doctors tested these, suggesting improvements to nozzle taper, actuation feel, and tool length for better access. The final high-fidelity prototype combined PLA and TPU materials, featuring a protected silver nitrate cartridge, ergonomic grip, and click-to-actuate control for precise deployment. User-centered design guided iterative development through clinical feedback, focusing on visibility, control, safety, and tactile confidence. The process taught the team the importance of collaboration, empathy, and rapid prototyping in healthcare innovation. Clinicians responded positively, highlighting potential adaptations and cost-effective production for broader use.
How it is different
Our design is unique to its own where there has not been a device that utilises silver nitrate to facilitate deeper nasal cautery. Although there are similar qualities to that of articulating guide wire, our design imparts itself where the articulating end is able to be separated from the main body. It is a two-part tool where we meet in the middle for disposable equipment and reusability. The mechanisms in the tool are thought out through the combination downsizing and the streamlining of delivering a miniscule robust control where the user can mechanically "feel" what the tool is doing. Having a chemical cautery device that facilitates the treatment will ease the burden that the burdens of the doctors by providing them a tool to control the movement of chemical instead of reinventing another method for cautery. Instead, this tool focuses on the delivery of proven existing technology by making it more accessible and readily deployable.
Future plans
Future plans include making the main body universal, with attachable front-end units specialised for tasks like forceps, vacuum, or nasal cauterisation. This all-in-one system, like a drill with interchangeable heads, allows doctors to perform diverse delicate procedures with one tool. It is easy to use, minimises setup time, and enables cost savings by replacing only worn parts. The goal is to reduce the need for multiple specialized tools in clinics, making treatments more accessible and safely performed by general practitioners without referrals.
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