Surgery: kinesitherapy – Kinesitherapy – Ultrasonic
Reexamination Certificate
2001-05-03
2003-07-08
Bennett, Henry (Department: 3737)
Surgery: kinesitherapy
Kinesitherapy
Ultrasonic
Reexamination Certificate
active
06589191
ABSTRACT:
The invention concerns a manually actuable ultrasonic disintegrator for producing small passages in muscle tissue, in which both pressure amplitudes/shock waves are introduced into the surrounding tissue by way of power ultrasonics and also simultaneously a definedly thermal input can be applied to the surrounding tissue. The invention further serves for breaking up or removing human or animal tissue, comprising a sonotrode for the transmission or ultrasonic waves and locally delimited high-frequency voltage at its distal end to the tissue, an ultrasonic transducer which can be coupled to the proximal end of the sonotrode, and a passage which extends lengthwise of the sonotrode for flushing and/or sucking away disintegrated and/or cleared-away tissue and/or also for the transmission of sonotrode is also supplied, with its return electrode disposed in the direct proximity, with HF-voltage, by way of an external high-frequency voltage source. The sonotrode serves here for the simultaneously transmission of power ultrasonics and high-frequency voltage.
As is known, high-power ultrasonic waves are used for breaking up and/or clearing away tumour tissue. The tumour cells to be destroyed burst by virtue of the high pressure amplitudes and cavitation phenomena of the ultrasonic waves used, involving a high level of power density. A conventional ultrasonic disintegrator which can be actuated by hand includes an ultrasonic transducer, generally a piezo composite transducer, which is coupled directly or indirectly to a sonotrode. The sonotrode serves to transmit the ultrasonic waves produced by way of its active surface by the ultrasonic transducer, to the tissue to be cleared away, in the form of longitudinal waves. Preferably, in the known units, a mechanical amplitude transformer is connected between the ultrasonic transducer and the sonotrode, and the amplitude transformer provides that the ultrasonic waves which are transmitted to the sonotrode are of a suitable amplitude for disintegrating and clearing away or ablating the tumour cells. In the known units, the ultrasonic transducer, the amplitude transformer and the sonotrode are disposed in an elongate, handle-like housing, wherein the distal end of the sonotrode projects from a distal opening of the housing, at which the unit can be held and guided by hand.
Ultrasonic boring of materials is known from the industrial use of power ultrasonics. When suitable sonotrode geometries are involved, the high mechanical removal forces which power ultrasonics entail mean that holes or passages can be produced in the most widely varying materials, both hard and soft, without involving a substantial application of force.
At the present time predominantly pulsed laser systems are used, known by the term ‘Trans-Myocardial Laser Revascularisation’, in which respect in particular at the present time units from PLC/USA, CARDIO GENESIS/USA and United States Surgical Corporation/USA are used. With those pulsed laser systems, utilising the mechanism of what is referred to as photoablation, it is possible to form transmyocardial passages and, by virtue of the system involved, in that case thermally influenced edge zones are produced and also, due to the process of photoablation, shock waves. It will be noted however that the magnitude of the thermally influenced edge zone and the amplitudes and depth effect of the shock waves cannot be regulated and optimised separately from each other. In addition these systems are extremely expensive.
Surprisingly it was found that the successes achieved hitherto when using those high-energy laser systems can be essentially attributed to two laser-induced effects:
The production of intramuscular shock waves due to the process of photoablation of a fast local thermal explosion for vaporisation of the tissue in the target region and due to the thermal damage to the edge zones which is ultimately inevitable in principle with this kind of laser use (what is meant is the process of photoablation) and which, depending on the setting parameters which are respectively used for the above-indicated lasers, extends from carbonisation through coagulation to extreme hyperthermia. It was now possible to show in a manner that was entirely surprising even for experts in this field that the acute successes with this process, which have previously been reported, are essentially to be attributed to secondary effects of the shock waves produced and pressure amplitudes related thereto, and that the long-term successes are essentially to be attributed to the formation of the thermally influenced edge zone of the passages formed. In the case of the systems used in accordance with the state of the art, it is a priori completely impossible to optimise the mode of operation of the shock waves, that is to say the resulting pressure amplitude and pressure shock duration, as well as the depth action connected therewith, separately from the thermal edge damage effects which occur when implementing the process. It is likewise completely impossible for the clearly advantageous formation of a thermal edge zone to be further optimised separately from the shock waves to achieve and optimise the reported long-term successes.
In regard to the general disintegration of tissue it is not possible, in spite of the selectivity of ultrasound, to prevent relatively small vessels also being broken up. The consequence of this is haemorrhages which cannot be stemmed with the ultrasonic instrument as ultrasonic disintegration is an athermal process. In some known units that problem is resolved in that a hollow sonotrode which is preferably made from titanium is fed with a high frequency alternating current (HF-current). By virtue of suitable development of heat, the electromagnetic high-frequency fields generated at the distal end of the unit in the tissue coagulate the surrounding tissue, whereby finally a haemorrhage can be stemmed.
In that known generation of an electromagnetic high-frequency field, the sonotrode is connected as an electrode while the counterpart electrode is applied from the exterior to the human body—in the region of the treatment zone. That involves what is referred to as a monopolar arrangement in which the current flows through a large part of the body to the counterpart electrode which is generally disposed at one of the extremities.
U.S. Pat. No. 5,312,329 discloses a unit of the kind set forth in the opening part of this specification, in which there is provided a tubular hollow passage along the longitudinal axis of the sonotrode. The mouth opening of the passage is surrounded by the active surface of the sonotrode. The passage leads into the interior of the housing and is isolated from the other electronic and mechanical components in the housing. A vacuum pump can be connected to the passage so that tissue fragments or body fluid or the fumes produced upon coagulation, can be sucked away from the body by virtue of a vacuum produced in the cavity. The passage is likewise used to feed a fluid to the treatment area of the sonotrode in order to liquefy the cell fragments and thereupon suck them away. For that purpose the passage can be connected to a fluid container which provides the flushing fluid.
The consequence of the arrangement of sonotrode and passage, which is known from U.S. Pat. No. 5,312,329, is that the active surface of the sonotrode, that is to say the end face of the sonotrode at its distal end, which provides for the transmission of ultrasonic waves to the tissue, is relatively small, but the outside diameter is nonetheless relatively large due to the presence of the internal flushing passage. Because the removal rate of a sonotrode at constant frequency and constant amplitude is approximately proportional to the active surface thereof, the mouth opening of the passage in the active surface of the sonotrode causes a reduction in the active surface and thus the removal rate. That reduction is remedied by the outside diameter of the active annular surface being increased in size. In the case of that known unit however th
Beck & Tysver P.L.L.C.
Bennett Henry
Dagostino Sabrina
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