The valves and tributary veins of the saphenofemoral junction: ultrasound findings in normal limbs

In the past the saphenofemoral junction (SFJ) for the surgeon was regarded as a simple conduit to be obliterated. With modern ultrasound we can distinguish the components of this complex structure and examine their haemodynamic function and suggest more haemodynamically-focused interventions. Despite this, there are no ultrasound studies describing the components of the normal SFJ and their haemodynamic significance. Patients attending our vascular laboratory with suspected deep vein thrombosis were screened and the SFJ in 75 limbs with no physiological or haemodynamic abnormalities were examined. The terminal (TV) and preterminal (PTV) valve morphology and the distance from the SFJ were assessed. The number of tributaries and their position relative to these valves was also examined. TV and PTVs were identified on ultrasound in all 75 limbs. TVs were found at a mean distance of 0.4 cm (range 0–1.2 cm) from the SFJ. Nearly a third of all limbs had at least one tributary vein identified superior to the TV. The greater the distance to the TV, the greater the number of tributary veins one should expect to find superior to the TV. PTV location was more variable. PTVs were identified at a mean distance of 3.1 cm (range 0.4–8.7 cm), giving rise to a large number of configurations of tributary veins in the intervalve space. This study characterizes the ultrasound appearances of the normal SFJ and compares these with reported anatomical studies. Valves can be consistently identified whereas the number and location of the tributaries are very variable. This should inform planning of haemodynamically-focused treatment at the SFJ.