Simple fixation of part of one vertebra (not motion segment) including pars interarticularis, spinous process or pedicle, or simple interspinous wiring between 2 adjacent vertebral levels, not being a service associated with: (a) interspinous dynamic stabilisation devices; or (b) a service to which item 51021, 51022, 51023, 51024, 51025 or 51026 applies (Anaes.) (Assist.)