CGS Medicare in the below link references a CMS MLN Matters article for 73 74 52 that describes specifically these modifiers being used for hospital billing. The true definition includes outpatient hospital and ASC. Like the other post you received they were indicating modifier 53 if you were reporting for the physician service which you would report 53 instead. But without the procedure technically being started/without incision, modifier 53 would be hard to justify.
http://www.cgsmedicare.com/parta/pubs/news/2014/0814/cope26558.html
?MLN Matters Number MM3507, "Use of Modifiers -52, -73 and -74 for Reduced or Discontinued Services External PDF
OPPS modifiers ?52, ?73 and ?74 are used to report procedures that are discontinued by a physician due to unforeseen circumstances, and for surgeries and certain diagnostic procedures requiring anesthesia:
? The hospital may receive 50 percent of the OPPS payment amount for the discontinued procedure if: ? The procedure is discontinued after 1) the beneficiary was prepared for the procedure and 2) the beneficiary was taken to the room where the procedure was to be performed.
? The hospital may receive the full OPPS payment amount for the discontinued procedure if: ? The procedure is discontinued after 1) the beneficiary has received anesthesia or 2) the procedure was started (e.g., scope inserted, intubation started, incision made). To provide additional clarity:
? Modifier ?73 is used by the facility to indicate that a surgical or diagnostic procedure requiring anesthesia was terminated due to extenuating circumstances that threatened the well being of the patient after the patient had been prepared for the procedure and been taken to the procedure room.
? Modifier ?74 is used by the facility to indicate that a surgical or diagnostic procedure requiring anesthesia was terminated after the induction of anesthesia or after the procedure was started, e.g., the incision made, intubation started, or scope inserted.
? Modifier ?52 is used to indicate partial reduction or discontinuation of radiology procedures and other services that do not require anesthesia. Note that discontinued radiology procedures that do not require anesthesia may not be reported using modifiers ?73 and ?74.