The invention relates to an HF surgical appliance having an HF generator and an additional transformer.
HF surgical appliances are known for a plurality of possible applications. With some of these possible applications, the load impedance lies between 0.1 and 1 kΩ, with other possible applications, the load impedance can be even lower. In particular, when a transurethral resection of the prostate (TUR) is to be performed with a bipolar instrument with a highly conductive irrigant fluid (NaCl 0.9%), the load impedance is only about 20Ω.
To be able to perform a load adaptation with a conventional HF surgical appliance, as shown in
It is an object of the embodiments of the invention to provide an HF surgical appliance of the type discussed above in which adaptation to low loads is also enabled.
This object is achieved by an HF surgical appliance comprising an HF generator having an output circuit, which contains an output transformer, has an output impedance and comprises output terminals to which an HF surgical instrument for supplying a high-frequency current with a specific frequency into tissue for treating the same can be connected. An additional output circuit, which contains an additional transformer connected between the output circuit and the output terminals to reduce the output impedance is also provided.
The additional output circuit can either be embodied as an external additional appliance or mounted in the HF surgical appliance. This ensures, in a simple manner, that a conventional surgical appliance can be used for special purposes (with a low-resistance load) with a little amount of work.
Preferably, the additional transformer is embodied as an autotransformer so that the galvanic separation is provided by the transformer provided in the HF surgical appliances. This additional transformer comprises an asymmetric or, preferably, a symmetrical winding.
The additional transformer preferably has a small air gap, particularly no air gap. This enables the adaptation to be optimized. In addition, the additional transformer is preferably a low-scattering transformer. Moreover, the inductance of the additional transformer is preferably more than 1 mH.
The additional output circuit also comprises a capacitor between the additional transformer and the output terminals. It is preferable, however, that a resonant circuit having a resonant frequency above the specific frequency of the generator be provided. This further improves the adaptation to the load.
Exemplary embodiments of the invention will be described in more detail with reference to drawings, in which:
In the following description, the same reference numbers are used to refer to the same parts and parts with the same function.
The embodiment shown in
Number | Date | Country | Kind |
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10 2009 012 600.7 | Mar 2009 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP10/01178 | 2/25/2010 | WO | 00 | 11/1/2011 |