Operating room personnel

I’m a surgeon and have questions regarding nursing in the OR. Does anyone know what the personnel requirements are in an operating room for endoscopies, laparoscopic cases, open bowel cases, simple excisions etc? For example, in a lap chole there is the surgeon, the circulator, a scrub and then is it required to have another person to assist? Does the AORN or ACS or other governing body have guidelines? Any help is appreciated...TIA!!!