• Free flap procedure codes are global and include: 

1. Elevation of the flap 
2. Isolation of donor flap vessels used for microvascular anastomosis 
3. Transfer of the flap to the recipient site 
4. Isolation of the recipient vessels used for microvascular anastomosis 
5. Microvascular anastomosis of one artery 
6. Microvascular anastomosis of one or two veins 
7. Inset of the flap in the recipient site 
8. Primary closure of the donor site

• Consider distal blood flow when performing anastomosis (consideration of end to side vs end to end)

 

• Flap Patency
• Skill #1 determinant for patency rates 

• Venous couplers shown to decrease anastomotic time

• Couplers can manage vessel size mismatch, contraindicated in atherosclerosis
• Couplers decrease complication rate vs. Hand-sewn anastomosis in head and neck free flap reconstruction 
• Couplers should not be used in recipient vein less than 2.0mm (ie 1.5mm coupler) due to increased rates of venous thrombosis 
• There are no known increased complications with use of vasopressive medications
• Known risk factors for thrombosis: AT deficiency, antiphospholipid syndrome, factor V leiden mutation, perioperative tamoxifen
• Patients with autoimmune disease/concern for increased risk of thrombosis should undergo formal hematology consult and anticoagulation workup prior to surgery, with anticoag plan based on that workup
• Heparin is used to improve patency rates

 

• Medications:
• Dextran: decreases factor VIII and VWF resulting in decrease in platelet function/aggregation, modifies structure of fibrin (increases susceptibility to degradation), volume expander, inhibits alpha-2-antiplasmin –> leads to activation of plasminogen (antithrombotic)
• Risks:
• Has antigenicity, give test dose 1-2 minutes prior to infusion
• Improved flap survival has not been demonstrated
• ARDS can result from dextran use
• Can cause ARF, avoid in patients with chronic renal insufficiency
• increased systemic complications
• Papaverine is a PDE inhibitor & vasodilator (phospodiesterase)
• Hirudin and heparin inhibit thrombin, asa inhibits thromboxane by inhibiting COX

 
 

• Flap Monitoring
• NIRS (near infrared spectroscopy): non-invasive modality that allows continuous monitoring of tissue oxygenation saturation (percent of hemoglobin that is oxygenated)
• Improves flap salvage rates (thought to be due to early recognition before it is obvious on clinical examination)
• Buried or partially buried free flaps best monitored by implantable dopplers (especially with omental flaps)
• Have been shown to have improved salvage rates compared to clinical monitoring, but also have higher false-positive rate 

 

• Flap Salvage
• Tpa: 
• Fibrinolytic agent that breaks down clots by activating plasminogen to plasmin
• Decreases the rate of fat necrosis but not flap salvage
• For venous thrombosis, TPA is successful and re-establishing blood flow use in conjunction with thrombectomy
• Do not administer systemically!
• Earlier reoperation improves flap survival –> take the patient back if there is concern for flap compromise! 
• Most common time for thrombosis is 0-24 hours (most within 12) especially in head and neck
• Multiple reoperations are predictor for unsuccessful flap salvage
• Arterial thrombosis is associated with lower salvage rates than venous thrombosis or external causes
•