Varicose vein treatments range from conventional surgical ligation and sclerotherapy to venous closure using biological adhesives. However, considering ease of procedure, recovery time, and cosmetic outcomes like minimal scarring, minimally invasive techniques employing lasers or radiofrequency are preferred. The efficacy of these methods heavily relies on clinician expertise and ultrasound imaging, with manual catheter retraction during cauterization presenting challenges, such as overlapping or untreated areas, especially in long vessels exceeding 1 meter, leading to increased procedure time and operator fatigue. To address these issues, we propose an automated catheter procedure for varicose veins. This system features a handpiece for energy generation control (laser, radiofrequency) operated near the clinician for convenience. We designed a pullback system that enables constant speed rotation and forward/backward movements of the catheter without moving the handpiece. Through handpiece operation, the catheter rotates at a set speed, and a roller-driven pullback action occurs as it winds on a reel, expanding the diameter of the reel for retraction while remaining stationary. Conversely, reducing the diameter of the reel facilitates forward movement. The length adjustment of the catheter based on winding turns on the reel makes it adaptable for various vascular procedures, enhancing the procedural accuracy and operator convenience.

Chronic wounds necessitate periodic treatment and management due to their potential for serious complications. Recently, ultrasonic mist therapy has been introduced to treat chronic wounds efficiently. This therapy requires a noncontact spraying method to prevent side effects such as bacterial infections and pain. Therefore, research is needed on a spray nozzle tip that can effectively transmit ultrasonic energy to the wound target with misted cleaning solution mobility in a specific direction and at an appropriate speed. The performance of the nozzle tip is greatly affected by the flow characteristics inside it. Computational fluid dynamics (CFD) is a powerful tool to analyze these characteristics in detail. The behavior of the mist was analyzed in a simulation based on discrete phase model methodology in an unsteady state. Valid design parameters enabling noncontact cleaning were determined by setting the design parameters of the nozzle tip`s internal flow path and measuring the spraying speed of the mist using CFD analysis. Through the simulation results, information on the sprayed skin surface and spray characteristics are measured. Lastly, we present a nozzle tip design guide optimized for ultrasonic mist therapy.