From a JAMA Network online study (February 11, 2020):
In this analysis of commercially insured patients who had undergone elective surgery with an in-network surgeon at an in-network facility, approximately 1 in 5 received an out-of-network bill, with a mean potential balance bill of $2011.
In this retrospective analysis of 347 356 surgical episodes among commercially insured patients who had undergone elective surgery with in-network primary surgeons and facilities, 20% of episodes involved out-of-network charges.
The patterns of out-of-network bills varied with the clinical scenario. Simpler ambulatory procedures that tend to involve 1 surgeon (arthroscopic meniscal repair, breast lumpectomy) had fewer out-of-network bills (13%-15% of cases), whereas inpatient procedures (hysterectomy, knee replacement, colectomy, CABG surgery) had more frequent out-of-network bills (24%-33% of cases). These more complex procedures were also associated with larger potential balance bills, in the range of $2000 to $4000.