Methodological assessment of the reduction of dissemination risk and quantification of debris dispersion during dissection with a surgical aspirator.

OBJECTIVE: We developed an actuator-driven pulsed water jet (ADPJ) device to achieve maximal lesion dissection with minimal risk of normal structural damage. Despite the unique dissection characteristics, there is a risk of dissemination of tissue dispersion; however, there is no established method to quantify the dispersion. Hence, this study aimed to assess the factors associated with dispersion and propose a simple experimental method using spectrophotometry to evaluate the degree of dispersion in a wet field. RESULTS: Methylene blue-stained brain phantom gelatin was immersed in a chamber with distilled water solution and dissected with an ADPJ. The dispersed gelatin solution was stirred and warmed to dissolve. The absorbance of the solution was measured spectrophotometrically. First, a reference standard curve was constructed to confirm the relationship between the absorbance and the amount of the dispersed gelatin. A clear proportional correlation was observed, which indicated that absorbance measurements can help evaluate the amount of dispersion. Using this method, we revealed that a high dissection force, insufficient suction, and inappropriate long distance between the nozzle tip and the target were associated with increased dispersion. This method might constitute a versatile and reliable approach to evaluate dispersion and aid in the development of surgical devices.

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.

The effectiveness of an actuator-driven pulsed water jet for the removal of artificial dental calculus: a preliminary study.

BACKGROUND: While hand and ultrasonic scalers are the primary tools used for the removal of dental calculus in periodontal treatment, many studies have shown that they also damage the enamel surface. We have developed a novel actuator-driven pulsed water jet (ADPJ) system, which has the ability to selectively remove materials depending on their stiffness. Considering the different material properties between teeth and dental calculus, it might be possible to develop the ADPJ to remove dental calculus without damage to the tooth's enamel surface using a suitable jet pressure. Therefore, the aim of this study was to assess the effectiveness of the ADPJ in removing dental calculus, and the surface features of the teeth after its use. METHODS: A total of 93 artificial teeth coated with artificial dental calculus were examined in this study. The weights of 90 teeth were measured before and after the use of ADPJ, which had an applied voltage setting of 150, 200, or 240 V. The three remaining teeth were instrumented with a conventional hand scaler, ultrasonic scaler, or ADPJ (set at 240 V). Damage to the artificial tooth surfaces was evaluated using 5% Evans blue dye under an optical microscope. Furthermore, apatite pellets, which are utilized as experimental substitutes for natural teeth, were assessed after the use of ADPJ and both conventional scalers. RESULTS: The ADPJ significantly reduced the amount of artificial calculus, and the removal rate was dependent on the applied voltage. No damage was observed on the surface of the artificial tooth and apatite pellet following the use of ADPJ, in contrast to the conventional scalers. CONCLUSIONS: The results of this study demonstrate the in vitro effectiveness of ADPJ in the removal of dental calculus, without causing damage to tooth surfaces.