Medical instrument with rotary end effector, position sensor, and electromagnetic interference reduction

An apparatus, comprising:

• (a) a medical instrument, the medical instrument comprising:
• (i) an instrument body,
• (ii) a shaft assembly extending distally from the instrument body, and
• (iii) an end effector at a distal end of the shaft assembly, the shaft assembly being operable to drive rotation of the end effector about a longitudinal axis, the medical instrument being configured to generate interference in an electromagnetic field while the end effector rotates about the longitudinal axis;
• and
• (b) a navigation adapter, the navigation adapter comprising:
• (i) an adapter body defining a bore, the bore being sized to receive a portion of the medical instrument, the adapter body further being configured to be fixedly secured to the medical instrument while allowing rotation of the end effector about the longitudinal axis, and
• (ii) a first position sensor supported by the adapter body, the first position sensor being configured to generate a signal indicating a position of the first position sensor in three-dimensional space, the first position sensor being oriented to offset the interference generated by the medical instrument.

An apparatus, comprising:

• (a) a body, the body including:
• (i) a laterally presented recess, the laterally presented recess being configured to receive a distal portion of a shaft assembly of a medical instrument,
• (ii) a distally presented recess adjacent to the laterally presented recess, the distally presented recess having a proximal engagement surface, the distally presented recess being configured to receive an end effector of the medical instrument, the end effector being disposed at a distal end of the shaft assembly, the proximal engagement surface being configured to engage a distal end of the end effector, and
• (iii) a latch, the latch being configured to retain the shaft assembly and the end effector relative to the body;
• and
• (b) a position sensor, the position sensor being secured relative to the body at a fixed distance from the proximal engagement surface, the position sensor being configured to generate a signal indicating a position of the position sensor in three-dimensional space.