Among hospitalizations for nonmaternal and nonneonatal conditions in 2012, more than one-fourth of stays and half of hospital costs involved stays that included operating room (OR) procedures.

■ The most common inpatient OR procedures in 2012 involved the musculoskeletal system: knee arthroplasty, laminectomy, hip replacement, and spinal fusion.

■ Between 2003 and 2012, the inpatient OR procedures with the greatest change in rate of occurrence overall were gastrectomy (+10.9 percent) and transurethral prostatectomy (TURP) (–10.4 percent).

■ Comparing age groups—Spine and joint procedures were common among all age groups except infants. Brachytherapy (internal radiation therapy) among adults aged 45–84 years had the greatest change in rate of any inpatient OR procedure in any age group, decreasing by about 26 percent annually between 2003 and 2012.

■ Comparing men and women—Musculoskeletal procedures were common among both men and women. The OR procedure with the greatest change in rate among men was brachytherapy (–30.2 percent) and among women was gastrectomy (+14.9 percent).

■ Comparing payer groups—Knee arthroplasty was the most common OR procedure for stays paid by Medicare and by private insurance. Cholecystect-omy was most common for stays paid by Medicaid and for uninsured stays.