Endoscope insertion cannula assembly

DETAILED DESCRIPTION The present invention provides an insertion cannula assembly with a locking mechanism for holding an endoscopy instrument in a desired orientation with respect to an insertion cannula tube.
The locking mechanism orients the endoscopy instrument in a desired rotational orientation regardless of the rotational orientation of the endoscopy instrument before it is inserted into the cannula assembly and locks the instrument into its desired axial and rotational position to maintain that position during use.
The locking mechanism also provides a tight fluid seal between the cannula assembly and the endoscope so that fluid may be aspirated from or irrigated into the operative site.
In this patent application the word "proximal" will be used to indicate that portion of a device closest to the end which projects outside the body.
The word "distal" will be used to describe that portion of the device closest to the end inside the body.
The endoscope insertion cannula assembly of the present invention includes a cannula housing with a cannula tube extending distally from the housing.
The housing is equipped with a port through which irrigation and aspiration fluid can be introduced down the cannula tube.
The cannula housing has an expanded internal diameter for accepting an endoscope and its associated adapter, guide and locking mechanism.
The adapter is a generally cylindrical device, the exterior dimensions of which are tailored to the interior dimensions of the cannula housing.
The interior dimensions of different adapters can be varied to accommodate different endoscopes.
The endoscope fits through the center of the adapter and projects into the cannula tube.
As mentioned previously, it is important to keep the end of the endoscope instrument, for instance a telescope, in proper rotational and axial register with the end of the cannula tube.
A guide is affixed about the exterior of the adapter and includes a distal surface which is disposed at an angle to the center line of the adapter