Investigation of Frequency Characteristics in Cutting of Soft Tissue Using Prototype Ultrasonic Knives (original) (raw)
Related papers
Physics of ultrasonic surgery using tissue fragmentation: Part I
Ultrasound in Medicine and Biology, 1996
Ultrasonic surgical aspirators typically operate at a frequency between 20 and 60 kHz. A vibrating hollow horn moves against the tissue and suction is applied. The interaction causes tissue to fragment; the fragmented material is then aspirated. However, the mechanism of interaction is poorly understood: the most common view relates it to cavitation, probably active in coucert with other mechanisms, including the direct jack-hammer effect, shock-induced stress, acoustic micro&reaming and shearing stress. It has also been attributed to chopping, which will produce emulsification. This article reports a study that collected and analyzed ultrasonic, high-speed photographic, visual/optical and electrical data for a 23-kHz unit operating in water and a range of fresh pig tissues. The primary mechanism for tissue fragmentation is shown to be horn-tip impact and other mechanical forces, operating in combination with hydrodynamic forces applied to the tissue on the forward stroke in each cycle. No evidence of cavitation in tissue was observed.
Physics of ultrasonic surgery using tissue fragmentation: Part II
Ultrasound in Medicine and Biology, 1996
Ultrasonic surgical aspirators typically operate at a frequency between 20 and 60 kHz. A vibrating hollow horn moves against the tissue and suction is applied. The interaction causes tissue to fragment; the fragmented material is then aspirated. However, the mechanism of interaction is poorly understood: the most common view relates it to cavitation, probably active in coucert with other mechanisms, including the direct jack-hammer effect, shock-induced stress, acoustic micro&reaming and shearing stress. It has also been attributed to chopping, which will produce emulsification. This article reports a study that collected and analyzed ultrasonic, high-speed photographic, visual/optical and electrical data for a 23-kHz unit operating in water and a range of fresh pig tissues. The primary mechanism for tissue fragmentation is shown to be horn-tip impact and other mechanical forces, operating in combination with hydrodynamic forces applied to the tissue on the forward stroke in each cycle. No evidence of cavitation in tissue was observed.
Physics of ultrasonic surgery using tissue fragmentation
Ultrasonics, 1996
Ultrasonic surgical aspirators typically operate at a frequency between 20 and 60 kHz. A vibrating hollow horn moves against the tissue and suction is applied. The interaction causes tissue to fragment; the fragmented material is then aspirated. However, the mechanism of interaction is poorly understood: the most common view relates it to cavitation, probably active in coucert with other mechanisms, including the direct jack-hammer effect, shock-induced stress, acoustic micro&reaming and shearing stress. It has also been attributed to chopping, which will produce emulsification. This article reports a study that collected and analyzed ultrasonic, high-speed photographic, visual/optical and electrical data for a 23-kHz unit operating in water and a range of fresh pig tissues. The primary mechanism for tissue fragmentation is shown to be horn-tip impact and other mechanical forces, operating in combination with hydrodynamic forces applied to the tissue on the forward stroke in each cycle. No evidence of cavitation in tissue was observed.
Soft tissue cutting with ultrasonic mechanical waveguides
AIP Conference Proceedings, 2012
The use of ultrasonic vibrations transmitted via small diameter wire waveguides represents a technology that has potential for minimally invasive procedures in surgery. This form of energy delivery results in distal tip mechanical vibrations with amplitudes of vibration of up to 50 µm and at frequencies between 20-50 kHz commonly reported. This energy can then be used by micro-cutting surgical tools and end effectors for a range of applications such as bone cutting, cement removal in joint revision surgery and soft tissue cutting. One particular application which has gained regulatory approval in recent years is in the area of cardiovascular surgery in the removal of calcified atherosclerotic plaques and chronic total occlusions. This paper builds on previous work that was focused on the ultrasonic perforation of soft vascular tissue using ultrasonically activated mechanical waveguides and the applied force required to initiate failure in soft tissue when compared with non-ultrasonic waveguides. An ultrasonic device and experimental rig was developed that can deliver ultrasonic vibrations to the distal tip of 1.0 mm diameter nickel-titanium waveguides. The operation of the ultrasonic device has been characterized at 22.5 kHz with achievable amplitudes of vibration in the range of 16-40µm. The experimental rig allows the ultrasonically activated waveguide to be advanced through a tissue sample over a range of feedrates and the waveguide-tissue interaction force can be measured during perforation into the tissue. Preliminary studies into the effects of feedrate on porcine aortic arterial tissue perforation forces are presented as part of this work. A range of amplitudes of vibration at the wire waveguide distal tip were examined. The resulting temperature increase when perforating artery wall when using the energized wire waveguides is also examined. Results show a clear multistage failure of the tissue. The first stage involves a rise in force up to some critical force and tissue displacement whereby the cut is initiated. The results show that with increasing ultrasonic amplitude of vibration the perforation force decreases considerably. The current results show that for the range of feedrates investigated 19-95 mm/min at an amplitude of vibration of 34.3 µm there was no significant effect on the perforation initiation force. The ΔT in the tissue 3.0 mm from the point of entry is also presented for a range of amplitudes of vibration.
Ultrasonically Assisted Cutting of Bio-tissues in Microtomy
Physics Procedia, 2016
Modern-day histology of bio-tissues for supporting stratified medicine diagnoses requires high-precision cutting to ensure high quality extremely thin specimens used in analysis. Additionally, the cutting quality is significantly affected by a wide variety of soft and hard tissues in the samples. This paper deals with development of a next generation of microtome employing introduction of controlled ultrasonic vibration to realise a hybrid cutting process of bio-tissues. The study is based on a combination of advanced experimental and numerical (finite-element) studies of multi-body dynamics of a cutting system. The quality of cut samples produced with the prototype is compared with the state-of-the-art.
Open Access Surgery, 2014
Background: A new ultrasonic device, Harmonic Focus ® +, has been developed that is smaller and delivers energy more efficiently than its predecessor via the inclusion of Adaptive Tissue Technology. This study was undertaken to compare its dissection capabilities to an advanced bipolar electrosurgery device in benchtop and preclinical evaluations. Methods: In ex vivo testing, Focus+ and LigaSure™ Small Jaw were evaluated for physical dimensions, device and tissue temperature after repeated applications to porcine jejunum, and burst pressure of vessel seals, transection time, and tissue sticking in 3-5 mm porcine carotid arteries. In in vivo testing, the devices were tested on intact porcine carotid arteries for thermal damage via collagen denaturation and in muscle incisions near rat sciatic nerve for acute inflammation via hematoxylin and eosin and for impaired axonal transport via β-APP. Results: Focus+ was smaller than the Small Jaw in width and height, yet it had a longer active blade and larger jaw aperture. Device temperatures were not different after application, but thermal spread (tissue temperature above 50°C) was 78% greater for Small Jaw (9.6 mm) than for Focus+ (5.4 mm). Burst pressures of sealed vessels were not significantly different between the devices: 900 (±466) mmHg for Focus+ versus 974 (±500) mmHg for Small Jaw. Small Jaw had a shorter individual transection time (5.0 seconds compared to 6.3 seconds for Focus+), whereas Focus+ had 70% less tissue sticking. Thermal damage, neural inflammation, and impaired axonal transport were all significantly lower for Focus+ compared to Small Jaw, by 19%, 57%, and 50%, respectively. Conclusion: With the addition of Adaptive Tissue Technology, Harmonic Focus+ builds upon the manifold advantages of ultrasonic devices in procedures requiring meticulous dissecting capability. Improvements in energy sensing and controlled delivery produce lower tissue temperatures and less thermal damage, especially critical when working near nerves. Focus+ produces vessel seal strengths equivalent to advanced bipolar devices and, although individual device activations are longer, the reduction in tissue sticking is expected to materially lessen operative time in clinical practice.
Journal of Materials Processing Technology, 2008
High-power low-frequency ultrasound in the range 20–60 kHz has wide ranging clinical applications in surgical and medical instruments for biological tissue cutting, ablation or fragmentation, and removal. Despite widespread clinical application and common device operating characteristics, there is an incomplete understanding of the mechanism of tissue failure, removal and damage. The relative contribution of cavitation, direct mechanical impact and thermal effects to each process for specific tissue types remains unclear. Different and distinct mechanisms and rates of tissue removal are observed for interaction with soft and hard tissue types. Device operating parameters known to affect the interaction include frequency, peak–peak tip amplitude, suction and application time. To date, there has been little analysis of the effect of variations in, and interactions of, these parameters on tissue removal and damage for individual biological tissue types. Potential controllable damage mechanisms occurring in tissues include alteration in global biomechanical properties, histomorphological changes, protein denaturation and tissue necrosis. This paper presents a critical review of the literature on the clinical application, mechanism of tissue interaction, removal and residual tissue damage. It describes known mechanisms for distinct tissue types.
The Journal of the American Association of Gynecologic Laparoscopists, 2001
Unipolar electrosurgery is a valuable energy source for the endoscopic surgeon; however, injury at a remote site from tissue being dissected remains a concern. Other energy sources have been available since the development of diathermy, including laser and ultrasonic energy. Ultrasonic energy as a cutting and hemostatic tool is relatively new. Since its introduction to laparoscopic surgery in 1993 1 it has been used in a variety of laparoscopic and open surgical applications; for example, in cardiothoracic surgery, where absence of electrical current is particularly important. 2 It has been used to perform cholecystectomies 3 and in splenic, 4 renal, 5 and bowel surgery. 6 In gynecology it has been used in laparoscopic-assisted vaginal hysterectomies 7 and myomectomies. 8
Ultrasonic bone cutting: Experimental investigation and statistical analyses of cutting forces
Scientia Iranica
Low cutting forces can signi cantly reduce the risk of damage to sensitive tissues adjacent to the bone. Because of its better control of the incision, lower cutting force and reduced postoperative complications, the application of ultrasonic tools in bone-cutting is of concern to surgeons. In this study, through the application of a full factorial design of experiments, the e ects of changes in cutting tool geometry, ultrasonic power, bone-cutting direction, and tool speed on the cutting forces of cortical bone are assessed simultaneously. The variance and regression of the experimental data are analyzed, and the impact of factors and interactions of the elements on the cutting forces are discussed. The adjusted coe cient of determination (R 2 adj) of the main cutting force and cutting resistance force of the statistical model were 91.49% and 91.15%, respectively. Both the blade geometry and ultrasonic power, together with their interactions, are the most in uential factors in the cutting forces, contributing 82.2% and 86.6%, respectively. The formation of teeth in the cutting edge improves the cutting process and reduces the cutting force by about 40%. To obtain high e ciency and low cutting force, it is recommended to use an ultrasonic-powered toothed edge blade with a pitch of 1 mm, a low vertical velocity, and a high longitudinal speed.
Journal of Vibroengineering, 2012
This paper presents a brief review of applications of ultrasound in modern surgery and results of original studies of the authors in the field of application of low frequency (24-36 kHz) high-intensity (up to 20 W/cm 2) ultrasonic vibrations for disruption of thrombi and calcified atherosclerotic plaques in blood vessels. Application of non-rigid wire ultrasonic waveguides with length up to 980 mm and diameter of working tip down to 0.3 mm enables minimally invasive surgical intervention, since a waveguide can be introduced along curved segments of blood vessels through a small incision situated at substantial distance from occlusion. Ultrasonic angioplasty can be successfully applied in combination with administration of thrombolytic drugs. The paper also considers physical mechanisms of thrombus disruption under influence of ultrasonic vibrations, particularly, effects of cavitation and acoustic streaming. We described design of ultrasonic waveguides for endovascular surgery and their manufacturing technology based on plasma-electrolytic etching. Application of finite element method and transfer matrix approach for design and model of wire waveguides is considered. Description of clinical system for ultrasonic angioplasty with automated resonance tuning of a waveguide is also provided. In addition, we report results of clinical application of ultrasonic angioplasty in patients with occlusion of iliofemoral segment.