Intraoperative common duct pressure and flow measurements.

Operative cholangiography is still the most accurate and available method for assessing the presence or absence of stones in the common duct. However, 30 to 40 percent of stones will still be overlooked with cholangiography. To reduce the incidence of overlooked common duct stones we recommended that pressure and flow measurements be obtained before cholangiography. When pressures are high or high normal and flows low, the duct should be explored even in the presence of a normal cholangiogram. Under these circumstances, the incidence of false-positive pressure flow studies is less than 5 percent even in inexperienced hands.