Ratchet-slide handle and system for fiducial deployment
Embodiments include a fiducial deployment system with a handle configured for actuation of same. A fiducial may include one or more protuberances configured to engage one or more slots in a needle of the system. The needle may be configured to deliver a plurality of fiducials to a target location in serial fashion, one at a time. The handle includes an actuation mechanism with a recessible-toothed rack and actuation member(s) configured for incrementally or otherwise controlledly deploying one or more fiducials at a time by advancing a stylet through and/or retracting the body of a slotted needle in which fiducials are disposed with a fiducial protrusion extending into the needle slot, which needle slot also includes retaining structures that do not impede the needle lumen.
1. A medical device handle configured for controlled incremental lengthwise stylet advancement through a cannula, the handle comprising:
an elongate outer handle body defining a longitudinal handle lumen;
an elongate cannula attached directly or indirectly to a distal end of the handle body, the cannula defining a longitudinal cannula lumen in mechanical communication with the handle lumen;
a rack member, including a plurality of longitudinally-aligned, laterally protruding and depressible, retractable, and/or foldable teeth, where the rack member is disposed within the handle lumen;
a stylet extending distally from the rack member into the cannula lumen; and
a pair of actuation members with a portion of the actuation members engaging against one of or between two or more of the plurality of teeth, where actuating of the actuation members by moving the actuation members longitudinally relative to the handle along a handle slot of predetermined length is effective to move the rack member distally by a predetermined lengthwise increment.
2. The medical device handle of claim 1 , where the predetermined lengthwise increment corresponds to a length of a fiducial.
3. The medical device handle of claim 1 , where the actuation members are urged proximally.
4. The medical device handle of claim 1 , where the rack member includes indicia, viewable through a window in the handle member, of a number of fiducials deployed by distalward movement of the rack member relative to the cannula.
5. The medical device handle of claim 1 , where the actuation members are configured as generally symmetrical sliders.
6. The medical device handle of claim 1 , where the rack member and the elongate outer handle body each are generally cylindrical with an outer diameter of the rack member—exclusive of the teeth—about the same or slightly less than an inner diameter of the handle lumen, and where the inner diameter of the handle lumen includes a recessed track allowing longitudinal movement of teeth of the rack member, and a portion of the recessed track comprises a keeper element.
7. The medical device handle of claim 1 , where the rack member teeth, the actuation members, or both, are configured for unidirectional distal rack-advancing engagement when the actuation members are moved distally, and are configured to allow non-rack-moving proximal reciprocation of the actuation members from a proximal handle slot end toward a distal handle slot end.
8. The medical device handle of claim 1 , where the rack member teeth flex out of a longitudinal linear axis in toward a longitudinal central axis of the rack member when contacted by the actuation members.
9. The medical device handle of claim 1 , where the rack member is generally longitudinally hollow along at least a lengthwise portion including the rack member teeth.
10. The medical device handle of claim 1 , where the rack member teeth each is generally shaped as a right triangle.
11. The medical device handle of claim 1 , where the base of each rack member tooth is flexibly attached to an elongate portion of the rack member, providing for reciprocal flexing, folding, or depression, with the teeth being biased to a default position aligned with a longitudinal axis of the rack member.