From the Agency for Healthcare Research and Quality:
Most hospitalizations involve one or more procedures, which can range from simple vaccinations to complex surgical procedures. The principal procedure is the procedure that is performed for definitive treatment (e.g., an appendectomy), but procedures can also be performed to make a diagnosis (e.g., tissue samples or exploratory surgery). Hospitalizations usually involve more than one procedure, which together constitute the all-listed procedures performed during a hospital stay.
This Statistical Brief presents data from the Healthcare Cost and Utilization Project (HCUP) on the most common all-listed procedures performed during hospital stays in the United States in 2010, overall and by patient age. Changes between 1997 and 2010 in the number of stays and the rate of hospitalization in the population are presented for hospital stays with the most common procedures performed in 2010.