Extendable ureteroscope sheath

A sheath assembly for use with an endoscope, comprising:

• an elongate tubular sheath configured to thread onto an elongate shaft of the endoscope, the elongate tubular sheath comprising a pliable segment at a distal end of the elongate tubular sheath;
• and
• a tensile filament extending along a circumference of the pliable segment to form a cinching loop at a distal end of the pliable segment, the tensile filament further extending proximally along the elongate tubular sheath,
• wherein:
• the elongate tubular sheath is displaceable along the endoscope between a retracted position and an extended position,
• a distal end of the endoscope extends distally beyond the pliable segment in the retracted position,
• the pliable segment extends distally beyond the distal end of the endoscope in the extended position to form a chamber,
• proximal displacement of the tensile filament tightens the cinching loop to convert the chamber from an open configuration to a closed configuration,
• the elongate tubular sheath includes:
• a sheath wall extending circumferentially around the chamber, the sheath wall defining an inside surface and an outside surface;
• and
• a filament lumen extending longitudinally along the sheath wall, the filament lumen disposed within the sheath wall between the inside surface and the outside surface, and
• a distal portion of the tensile filament is entirely disposed within the filament lumen, the distal portion extending longitudinally along the pliable segment.