Ultrasonic Knife Research Articles

Dermal microvasculature and tissue selective thinning techniques (ultrasound and water-jet) of short-time expanded skin in dogs.

Certain reconstructive procedures, like auricular reconstructions, require thin and well-vascularized skin. The aims of this study were to analyze if the increased survival of expanded skin flaps was due to morphologic changes of the dermis, if thinning of short-time expanded skin was possible without harm to the microcirculation and if tissue selective cutting methods could be used to resect subcutaneous fat without damaging its vessels. Eighty-two 200-ml expanders were implanted into the trunk regions of 26 beagles and filled immediately with sterile saline. In the first series of experiments, the expansion was terminated after intervals of 0.5-5 weeks and dermal vessels were analyzed morphometrically. In the second series the expanded flaps were raised after 2 weeks and thinned solely surgically or with the additional use of an ultrasonic knife or with cutting by water jet. In contrast to sham flaps, the expanded skin showed only very few areas of necrosis and these were located superficially in most cases. The relative volume of the dermal vessels and their quantity showed a significant increase after the expansion. Additionally, the subcutaneous tissue could be thinned down to 0.4 mm with the water-jet-cutter. Findings demonstrated that the method used could create a well-vascularized skin flap of minimal thickness that could be very helpful for special reconstructive procedures.

Improved ultrasonic knife

Disclosed is an improved ultrasonic knife of the type for surgical incision in various types of tissue and/or for the removal of cement within the body. The knife has a reduced thermal footprint to minimize thermally induced tissue damage. Tooth configuration on the knife cooperates with the stroke of the ultrasonic drive to produce efficient cutting, as well as tactile feedback to the surgeon with respect to the rate of cutting, and changes in tissue density. Ultrasonic knife tip extenders are also disclosed for advancing the ultrasonic knife tip through the working channel of an endoscope. Methods utilizing the foregoing apparatus are also disclosed.

Consistent modelling and control of compacting-sintering process: K.Z. Korczak (KZK Powder Technologies Corp, USA)

We study three-dimensional Khokhlov–Zabolotskaya–Kuznetsov (KZK) model of the nonlinear hydroacoustics with dissipation. This model is described by third order quasilinear partial differential equation of the (KZK). We obtained that the (KZK) equation admits an infinite Lie group of the transformations, depending on the three arbitrary functions. This is due to the fact that in the (KZK) model the main direction of the wave’s propagation is singled out. The submodels of the (KZK) model.are described by the invariant solutions of the (KZK) equation. We studied essentially distinct, not linked by means of the point transformations, invariant solutions of rank 0 and 1 of this equation. Also we considered the invariant solutions of rank 2 and 3. The invariant solutions of rank 0 and 1 are found either explicitly, or their search is reduced to the solution of the nonlinear integro-differential equations. For example, we obtained the invariant solutions that we called by “Ultrasonic knife” and “Ultrasonic destroyer”. The submodel “Ultrasonic knife” have the following property: at each fixed moment of the time in the field of the existence of the solution near a some plane the pressure increases indefinitely and becomes infinite on this plane. The submodel “Ultrasonic destroyer” contains a countable number of “Ultrasonic knives”. The presence of the arbitrary constants in the integro-differential equations, that determine invariant solutions of rank 1 provides a new opportunities for analytical and numerical study of the boundary value problems for the received submodels, and, thus, for the original (KZK) model. With a help of these invariant solutions we researched a propagation of the intensive acoustic waves (one-dimensional, axisymmetric and planar) for which the acoustic pressure, speed and acceleration of its change, or the acoustic pressure , speed and acceleration of its change in the radial direction, or the acoustic pressure, speed and acceleration of its change in the direction of one of the axes are specified at the initial moment of the time at a fixed point. Under the certain additional conditions, we established the existence and the uniqueness of the solutions of boundary value problems, describing these wave processes. Mechanical relevance of the obtained solutions is as follows: (1) these solutions describe nonlinear and diffraction effects in ultrasonic fields of a special kind, (2) these solutions can be used as a test solutions in the numerical calculations performed in studies of ultrasonic fields generated by powerful emitters. Application of the obtained formula generating the new solutions for the found solutions gives families of the solutions containing three arbitrary functions.

Even Bigger and Better Ultrasonic Profiling Machines

THE June, 1986, issue of “Aircraft Engineering” contained a comprehensive description of a custombuilt ultrasonic knife cutting machine which Design Technologies Ltd of Wellingborough has supplied to Westland Helicopters of Yeovil, where it is being used to cut pieces from non‐metallic uncured pre‐impregnated materials for composites such as graphite, fibre‐glass, and Kevlar for the manufacture of rotor blades for the new EH 101 helicopter.

CNC Controlled Ultrasonic Knife for Helicopter Blade Production

AN order for an advanced CNC controlled ultrasonic knife profiling machine for the volume production of carbon fibre and glass fibre helicopter blade components is among £426,000 new orders announced by Design Technologies Ltd, the new Wellingborough‐based supplier of advanced CNC high speed profile cutting systems formed after the recent management buy out of Desitech Ltd with the support of the British Linen Bank. These orders are in addition to the £1m work already in progress at the time of the buy out in April.

Experimental Study of Ultrasonic Surgical Knife

Three ultrasonic surgical knives (resonant frequency, 20 kHz) were made on a trial basis and used for incision tests in order to study their cutting quality. The cutting quality of the knives remained sharp through the experiment at an amplitude of more than 30 µm. Bloodless surgery without damage to the peripheral tissue was also proved to be feasible at an amplitude a's high as 80 µm, if sufficient heat is generated by the friction loss of the knives. For easy handling, trial miniaturized ultrasonic knives (resonant frequency, 50 kHz) were also made.

Bloodless intrasegmental liver resection with the aid of the ultrasonic surgical knife

With the new ultrasonic knife, it is feasible to resect portions of the liver without injury to the blood vessels or to the bile ducts. After ligating these vessels, hepatic resections are performed without significant blood loss.