Effect of endoscope flexibility on tissue dissection profile assessed with pulsed water jet device: ensuring safety, efficacy, and handling of thin devices for neuroendoscopic surgery

Objective We developed an actuator-driven pulsed water jet device (ADPJ) for flexible neuroendoscopy to achieve effective tissue dissection with vasculature preservation. Although flexibility is a strong advantage for minimally invasiveness, the effect of the ductile curvature on the dissection profiles remains unknown. The purpose of this study was to clarify the impact of the curvature change of the ADPJ connecting tube on the dissection safety and efficacy. Results Three ADPJ connecting tubes with different inner diameters (1.0, 0.75, 0.5 mm) were used to dissect the brain phantom. They were bent at 3 angles: 0°, 60°, and 120°. The dissection profiles were evaluated using the mean depth and coefficient of variation (CV) for efficacy and safety, respectively.The larger inner diameter connecting tube dissected more deeply. The dissection depth was not changed regardless of the curvature degree in each tube. There was no significant difference in CVs regardless of inner diameter and curvature. The ductile curvature of the flexible neuroendoscope did not affect the efficacy and safety of the ADPJ dissection profile. Among the numerous instruments, tube-formed devices, including suction and injecting devices such as ADPJ, can be used safely and effectively without flexibility-related limitations.

Effect of Endoscope Flexibility on Tissue Dissection Profile Assessed With Pulsed Water Jet Device: Ensuring Safety, Efficacy, and Handling of Thin Devices for Neuroendoscopic Surgery

Objective: We developed an actuator-driven pulsed water jet device (ADPJ) for flexible neuroendoscopy to achieve effective tissue dissection with vasculature preservation. Although flexibility is a strong advantage for minimally invasiveness, the effect of the ductile curvature on the dissection profiles remains unknown. The purpose of this study was to clarify the impact of the curvature change of the ADPJ connecting tube on the dissection safety and efficacy.Results: Three ADPJ connecting tubes with different inner diameters (1.0, 0.75, 0.5 mm) were used to dissect the brain phantom. They were bent at 3 angles: 0 °, 60 °, and 120 °. The dissection profiles were evaluated using the mean depth and coefficient of variation (CV) for efficacy and safety, respectively.The larger inner diameter connecting tube dissected more deeply. The dissection depth was not changed regardless of the curvature degree in each tube. There was no significant difference in CVs regardless of inner diameter and curvature. The ductile curvature of the flexible neuroendoscope did not affect the efficacy and safety of the ADPJ dissection profile. Among the numerous instruments, tube-formed devices, including suction and injecting devices such as ADPJ, can be used safely and effectively without flexibility-related limitations.

Numerical Simulation of Pulsed Water Jet Machining of Al 6061-T6 and Ti-6Al-4V

Aluminum, known for its low density and its ability to resist corrosion through passivation, is vitally important to the aerospace industry, transportation, and building industries. The most common problem when machining titanium using traditional metal cutting processes is that tools rapidly wear out and need to be replaced since the variation of chip thickness, high heat stress, high-pressure loads, spring back, and residual stress result in higher tool wear and worse machined surface integrity. Thus, a technique that allows high precision machining of titanium that preserves the integrity of the machined material, reduces tool wear or even eliminates tooling entirely is an important advance. This study examines the ability to machine Al 6061-T6 and Ti-6Al-4V using a pulsed water jet by simulation using ABAQUS Smoothed Particle Hydrodynamics (SPH). The aluminum results showed that between the three diameters the 0.4572 mm orifice is a better choice based upon the percent increase from the orifice diameter; but based off of the kerf, the 0.3556 mm is the better choice. The results show that the 621 MPa has the highest MRR for Al 6061-T6, 232.1 mm3/s. For the four pressure simulations for the titanium, the 138 MPa pressure has the smoothest surface. Even though the volume removed decreased as the pressures increased for the titanium, the MRR increased due to the shorter machining times with 621 MPa pressure having the second highest MRR, 170.051 mm3/s. The results show that overall the 621 MPa is the best choice from the parameters chosen for machining Al 6061-T6 and Ti-6Al-4V.

Attenuation of Liver Damage After Partial Liver Resection by Piezo Actuator-driven Pulsed Water Jet System and Faster Recovery of the Liver in a Rat Model: an Experimental Study

Background Pulsed water jet dissection is an emerging surgical method for achieving maximal resection of a lesion and postoperative function preservation. We aimed to clarify liver damage and long-term results after liver resection using a novel surgical device, piezo actuator-driven pulsed water jet (ADPJ), in a rat model.Methods We categorizedSprague–Dawley rats into four groups and subjected themto sham operation or liver resection using an ADPJ, an ultrasonic aspirator (UA), or a radio knife. At 1, 3, 7, 14, 28, and 56 days postoperatively, we euthanizedfive rats from each group after collecting blood samples and harvested residual livers.We measured serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and glutamate dehydrogenase (GLDH) concentrations. Morphological characteristics and resection surfaces were assessed by hematoxylin–eosin staining.ResultsOn day 1, serum AST and ALT levels were significantly lower with an ADPJ than with an UA and a radio knife (AST: ADPJ vs. UA, P<0.05, ADPJ vs. radio knife, P<0.01; ALT: ADPJ vs. UA, P<0.05, ADPJ vs. radio knife, P<0.01). GLDH levels on day 1 were significantly lower with an ADPJ than with other devices (ADPJ vs. UA, P<0.05; ADPJ vs. radio knife, P<0.01).Degree of degeneration from the resection surface was mild with an ADPJ. Number of rats in which denaturation completely disappeared was significantly more withan ADPJ than with other devices on day 28 (ADPJ vs. UA, P<0.05; ADPJ vs. radio knife, P<0.01).ConclusionsLiver damage afterliver resection was markedly less with an ADPJ than with an UA or a radio knife. Furthermore, the liver recovered faster after an ADPJ.

The Formation Principle and Characteristics of Self-supercharging Pulsed Water Jet

High-pressure pulsed water jet technology has high development potential in the field of rock fragmentation. Technical bottlenecks such as difficulty in pressurization and inconvenient frequency adjustment for existing types of pulsed jets, a self-supercharging pulsed water jet generation method is proposed based on the theory of pulsed water jet and principle of hydraulic boosting, which changes the flow direction of fluid medium through the valve core to make the piston reciprocate in the cylinder, and relies on the effective area difference between the front and rear chambers in the stroke stage of the piston to realize the organic combination of “pulse” and “supercharging” of the jet, so as to self-supercharging pulsed water jet. Based on revealing the formation principle of self-supercharging pulsed jet, the self-supercharging pulsed jet generation system was designed, and the self-supercharging pulsed jet testing platform was built, many groups of pressure collection and jet shape observation experiments were carried out for different operating parameters. The research results show that both the jet pressure and the jet shape show periodic change, and higher pulse pressure can be obtained at lower inlet pressure. The error of the pressure ratio calculated according to the experimental results is less than 3% compared with the theoretical design value, thus verifying the feasibility of the method . Pulse pressure and pulse frequency are controllable, that is, as the inlet flow rate increases in the stroke phase of the piston, the pulse pressure and pulse frequency increase, and the pulse duration decreases, as the inlet flow rate increase in the backward stroke phase of the piston, the pulse frequency increases, and the pulse pressure and pulse duration remain unchanged. The research results lay the foundation for enriching the theory of pulsed jet generation and expanding its application range.