# Investigation on the cutting-infiltration integrated strategy based on medical waterjet for targeted drug delivery

## TL;DR

A new water jet system combines tissue cutting with targeted drug delivery, reducing tissue damage and improving precision in surgery.

## Contribution

The study introduces a water jet system that integrates cutting and drug delivery, validated through experiments and imaging.

## Key findings

- Jet parameters like pressure and nozzle size strongly influence cutting depth and drug diffusion.
- The water jet system caused 51% less fiber breakage and 35% less tissue damage than traditional surgery.
- Photoacoustic imaging confirmed a 'cutting-guided diffusion' mechanism for anesthetics near the cutting depth.

## Abstract

The integration of cutting and anesthesia within a single surgical instrument presents a significant opportunity to increase precision and reduce mechanical injury. This study introduces an innovative integrated water jet system that synergistically combines tissue dissection with localized drug delivery. A dedicated experimental platform was developed on the basis of hydrodynamic principles, enabling synchronous cutting and anesthesia. Systematic evaluations were conducted through cutting-diffusion experiments, tissue surface morphology analysis, and spatial diffusion tracking of anesthetics via photoacoustic imaging. The results demonstrated a nonlinear positive correlation between jet parameters (pressure and nozzle diameter) and both the cutting depth and diffusion distance. The optimal performance was achieved at distinct parameters for different tissue types: 4 MPa with a 0.2 mm nozzle for muscle tissue, and 8 MPa with a 0.2 mm nozzle for adipose tissue. Compared with conventional scalpel excision, the water jet technique significantly reduced tissue damage, as evidenced by a 51% reduction in fiber breakage and a 35% decrease in damaged area, while preserving up to 39.45 μm of functional structure. Furthermore, photoacoustic imaging revealed nonmonotonic diffusion dynamics of the anesthetic, with the maximum diffusion distance occurring adjacent to the cutting depth (18.31 ± 2 mm), confirming a “cutting-guided diffusion” mechanism. These findings establish a foundational framework for device-drug synergy in surgery, advancing the development of multifunctional, minimally invasive technologies.