1. Field of the Invention
The invention concerns a flap valve for a trocar system according to the preamble of a patent 1.
2. Description of the Related Art
Trocar systems are being used in minimally invasive surgery to enable entrance to a body cavity, for example, into the visceral cavity. For this procedure, a guide tube (trocar cannula) with a trocar (obturator) inserted therein is passed through the abdominal wall. Subsequently, the trocar is removed and the guide tube remains as an access canal to the visceral cavity. In order to perform surgical procedures in the visceral cavity, it typically is insufflated. To avoid gas leakage from the visceral cavity, a valve is placed at the extracorporeal remaining proximal end of the guide tube, which closes automatically if no instrument is inserted.
To enable the insertion of a delicate instrument and avoid the entanglement of instruments during extraction, flap valves are used that can be manually opened. The flaps on the flap valves include part of a valve that closes, spring-biased, on an aperture, which aligns axially with the guide tube. The flap is pivotally operated against a spring force, perpendicularly to the exocentric pivoting axis of the lead-through opening.
From U.S. Pat. No. 4,654,030 it is known to affix a valve non-rotatingly (torque-proof) upon a pivot axle, and to provide a pivot lever on the end of the axle projecting out from the valve body for the manual actuation of the valve. The manipulation of the flap valve is unfavorable, because the surgeon has to support the trocar system with one hand and use the other hand for pivoting the valve.
In DE 3923243 C2, a flap valve of the previously mentioned type is disclosed. This flap valve is pivoted into the open position with the aid of a sliding rod. The sliding rod is slidable parallel to the axis of the releasable lead-through-opening. To operate the flap, the housing-inner end of the sliding rod engages the flap between the valve part and its pivoting axis. The space needed to operate the slide rod enlarges the radial and axial measurements of the body of the flap valve. Because of spatial reasons the slide rod must be attached very close to the middle axis of the body, so the handling of the slide rod is ergonomically unfavorable.
The object of the invention is to provide a flap valve for a trocar system with a compact configuration that allows an ergonomically favorable handling of the tool.
This task is inventively accomplished by a flap valve having the characteristics of Patent 1.
Preferred embodiments of the invention are set forth in the dependent claims.