cannula or imbedded in the cannula structure material various cannula are envisioned to be interchangeable with the endoscope 12 by unscrewing one guide cannula from the endoscope front hub 18 and its associated connector member 20 and screwing one another on to the connector member the endoscope 12 is provided with tube body 17 formed with objective lens 22 at its distal end and image guide 24 as is more clearly shown in fig2 the endoscope 12 has a proximal end in the form of a back member 26 having a light post 27 and a video port 29 as seen in fig3 the preferred cannula embodiment 30 as seen in fig5 has a cylindrical outer cannula or sheath 32 formed with a beveled distal end 34 as shown in fig4 or a cylindrical end as shown in fig2 the inner wall of sheath 32 defines a cylindrical inner channel 33 which has an inner cylindrical tube 36 eccentrically mounted thereon the tube 36 defines the endoscope channel 37 and holds endoscope 12 the inner cylindrical tube 36 is eccentrically mounted in cylindrical inner channel 33 to the wall of the cannula sheath 32 and its outer surface together with the inner surface of the sheath or tube 32 to define a moon shaped channel 38 which acts as a channel or passageway providing irrigation and aspiration and is also used as a port through which a fiber optic array or a laser probe 60.