Anatomy of the deep veins Below the knee Above the knee!Anterior tibial ! Popliteal Vein in popliteal fossa!Posterior tibial ! From confluence of 3 calf!Peroneal veins!Gastrocnemial ! To adductor canal!Soleal ! (Superficial) Femoral ! Profunda Femoris joins 4cm below inguinal!Variable ligament!Paired ! Common Femoral!Tricky! ! Long/ great saphenous!Relevance of DVT?
Here’s the problem It would be nice to scan But it’s hard! the below knee veins ! Variable!Incr sensitivity ! Paired!Incr accuracy ! Tiny ! Tricky!Variable ! And most of them don’t ermbolize!Paired ! (But some do…)!Tricky!!Relevance of DVT?
Previous top tip: justlook for above knee Leave the calves to the sonographers! 6
But Lichtenstein came up with a solution! Except for the anterior tibials, the below knee veins travel all in a line, a couple cm below the interosseous membrane! together with their arteries: 2 veins for each artery = 6 vessels, all lined up! We can see them from the front of the leg!! Probe between the tibia & fibula
Now we have 2 options1. Just above knee: leave the calves to the sonographers!2. Below knee (anterior approach) 8
Which sites can I compress?! Internal Jugular V! Subclavian V! IVC! Saphenofemoral confluence (up fem)! Lower (superf) femoral near adductor hiatus! Long saphenous V! Short saphenous V! Popliteal vein & trifurcation! Beloe knee veins
Which sites should I compress?! Up to you! The more veins you scan, the more sensitive you are… eg UL veins add 4% in PE! The fewer you scan, the less irritating it is! 3-point scan is reasonable 1. Upper femoral (confluence) 2. Lower femoral (near adductor hiatus) 3. Popliteal (irritating if supine) …or …below knee (weird at first)
1: Groin! Probe in transverse position! Start just below inguinal ligament! ‘Mickey Mouse’ sign ! Femoral A ! Saphenofemoral confluence ! Then compress
3: fem V just above knee! Adductor hiatus! Medial to the bone! Hand behind, presses forward
4: popliteal fossa! Lie patient on side, or lift leg! Popliteal vein ! Superficial to popliteal artery ! visualise bone beneath ! follow it to the trifurcation
5: below the knee! Supine patient! Probe transverse! Between tibia & fibula
Handy Hints as you go down the leg1. Decrease greyscale (dynamic range)2. Decrease frequency3. Increase depth as you go4. Obese: change to curved probe5. Sit with legs over bed / stand up6. Valsalva (humming works)7. Doppler …
Pitfalls! Duplicate venous systems (duplex popliteal up to 35%)! Non occlusive thrombus! LSV, SSV! Ant tibial veins! However … ‘90% = 100%’
One more time: Handy Hints ! You don’t need Doppler ! You don’t need linear probe ! But you won’t be 100% ! Below-knee isn’t that hard ! Sitting up / standing ! Valsalva (humming works)