| 摘要 |
A lacrimal bypass drainage device (1) uses a cannula or tube (2) having a flange on the ocular end and a threaded outer surface to provide for greater axial friction. The flange is keyed to allow engagement by a screwdriver type tool (4) having a correspondingly keyed trocar mounted to a manipulable handle. The trocar has a forward shaft portion for coaxially engaging the cylindrical lumen of the tube. The shaft portion has a front end formed into a blade and an opposite rear end formed into a radially widened haft. The haft carries two axially forward projecting prongs to engage correspondingly placed notches in the flange of the tube. The handle portion of the tool extends rearwardly from the haft. The blade can be formed into two frustoconical symmetric arcuate sections to enhance cutting during twisting manipulation of the tool. The trocar portion can be made to be replaceable for differently sized, shaped or bladed trocar portions. A removable biocompatible washer (3) is provided to discourage tissue overgrowth immediately after emplacement. One or more radial drainage holes can be formed near the distal end of the tube to overcome axial blockages. An alternate embodiment provides for a tube placed from the nasal side having nasal side radial protrusions and a removable eye side flange in the form of a keyed nut.
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