Microvascular Free Tissue Transfer

1. Microvascular Free Tissue Transfer Glen T. Porter, MD Shawn D. Newlands, MD UTMB-Galveston, TX October 2004

2. History Early 1900�s Alexis Carrel 1950�s Jacobsen and Suarez�anastomoses in animals 1959 Seidenberg� free jejunum segments to repair pharyngoesophageal defects (human) 1972 McLean and Buncke � omental flap to cover a cranial defect (first �microvascular� flap) 1973 Daniels and Taylor� �free flap� First free cutaneous flap 1976 Baker and Panje� first free flap in head and neck cancer reconstruction Groin flap pedicled on the circumflex iliac artery

3. Advantages of free tissue transfer Two team approach Improved vascularity and wound healing Low rate of resorption Defect size of little consequence Potential for sensory and motor innervation Permits use of osseointegrated implants

4. Advantages of free tissue transfer Wide variety of available tissue types Large amount of composite tissue Tailored to match defect Wide range of skin characteristics More efficient use of harvested tissue Immediate reconstruction

5. Recipient vessels Arteries Superficial temporal system �scalp and upper face Facial artery�midface and cervical region (atherosclerosis common) Superior thyroid or lingual artery�lower cervical region Other: thyrocervical trunk, external carotid, common carotid

6. Recipient vessels Veins External jugular Branches of internal jugular (common facial) Internal jugular Retrograde (superficial temporal, thyroid) Transverse cervical, occipital (very small)

7. Recipient vessels after previous neck dissection Gold standard: Angiogram (short-term injury to endothelium reported) Operative reports Long-pedicled flaps Thyrocervical trunk (transverse cervical), Occipital vessels, retrograde drainage (thyroid veins, superficial temporal), external carotid artery Contralateral vessels (recipient or graft) End-to-side anastomoses with large vessels Vein grafts Arteriovenous loop (poorer results)

8. Vessel selection Size Arterial vs.Venous Atherosclerosis XRT-related changes Vessel geometry (location and orientation) Vessel length

9. Vessel preparation Arteries need to have strong pulsatile flow�cut until it flows. Cut back beyond branches or ligate them if sufficiently distant from the anastomosis site. Atherosclerosis Intimal inspection Dilation Removing the adventitia

10. Irradiated vessels Technically more difficult�effects appear specific to arteries Higher incidence of atherosclerosis Vessel wall fibrosis, increased wall thickness, more intimal dehiscence No reported difference in outcome of microvascular anastomoses (Nahabedian MY, et al., 2004, Kroll SS, et al 1998) Microvascular anastomoses tolerate XRT well long-term (Foote RL., et al., 1994) Require careful handling, cut off clot (teasing thrombi may denude vessel wall��sticky� walls), smaller suture, needle introduced from lumen to outside wall (to pin intima to wall)

11. Prepare vessels Evaluate vessel geometry Trim, irrigate, dilate Partial flap insetting (bony cuts and plating done at donor bed, if necessary) Arterial vs. venous anastomosis first with early or delayed unclamping of first vessel showed no difference. (Braun, et al., 2003) Anastomosis of remaining vessel Complete flap insetting Microvascular Anastomosis

12. Microvascular surgical technique Trim adventitia 2-3mm Gentle handling (no full-thickness) Trim free edge, if needed Dissect vessels from surrounding tissues Irrigate and dilate Heparinized saline Mechanical dilation (1 � times normal �paralyses smooth muscle) Chemical dilation, if necessary Suturing

13. Microvascular suture technique 3 guide sutures (120 degrees apart) Perpendicular piercing Entry point 2x thickness of vessel from cut end Equal bites on either side Microforceps in lumen vs. retracting adventitia Pull needle through in circular motion Surgeon�s knot with guide sutures, simple for others Avoid backwalling�2 bites/irrigation

14. 3 suture technique

15. Vessel size mismatch Laminar flow vs. turbulent flow <2:1 � dilation, suture technique >2:1, <3:1 � beveling or spatulation (no more than 30 degrees to avoid turbulence) >3:1 � end-to-side

16. End-to-end vs. End-to-side Recent reports indicate end-to-side without increase in flap loss or blood flow rate. End-to-side overcomes size discrepancy, avoids vessel retraction, and IJ may act as venous siphon. End-to-side felt best when angle is less than 60 degrees (minimize turbulence) Vessel incision should be elliptical, not slit Can use continuous suture technique

17. End-to-side Anastomosis

18. Continuous suture technique May significantly narrow anastomosis May be used on vessels >2.5 mm Decreases anastomosis time by up to 50% Decreases anastomosis leakage Most commonly used for end-to-side anastomoses with large vessels

19. Mechanical anastomosis Devices Clips Coupler Laser Results Increased efficiency and speed, use in difficult areas Patency rates at least equal to hand-sewn (Shindo, et al 1996, De Lorenzi, et al 2002) Can be used for end-to-end or end-to-side (DeLacure, et al 1999) Poorer outcome with arterial anastomosis�20-25% failure (Shindo, et al 1996, Ahn, et al 1994)

20. Vein grafts Used in situation where pedicle is not long enough for tension-free anastomosis Usually harvested from lower extremity (saphenous system) Valve orientation is necessary Avoid anastomosis at level of vein valve Keep clamps in place until both anastomoses sewn Prognosis for success controversial (Jones NF, et al., 1996, German, et al. 1996) Recent literature  30% failure (vs. 5%) in 1993 study, German 1996 showed no difference, but revisions greater in vein graft cases (15% vs. 9%)30% failure (vs. 5%) in 1993 study, German 1996 showed no difference, but revisions greater in vein graft cases (15% vs. 9%)

21. Microvascular Hints & Helps Use background to help visualize suture Demagnetize instruments, if needed May reclamp vessels for repair after 15 minutes of flow Reclamp both arterial and venous vessels when revising venous anastomosis Support your hands and hold instruments like a pencil

22. Ischemia Primary and secondary Primary: 2.25-6 hours Secondary: 1-12 hours Interrelation No flow phenomenon Cold vs. normothermic In vitro studies show benefit to cooling of flaps In vivo studies show surface cooling (<4hr ischemia time) does not adversely effect flap success (Shaw W. et al 1996) Tissue specific critical ischemia times Metobolic rate dependent Perfusates (UW, tissusol, Viaspan, Heparin) Literature unclear

23. Anastomotic failure 93-95% success rate expected Venous thrombosis:Arterial thrombosis 4:1, ateriovenous loop, tobacco use significant factors (Nahabedian M., et al, 2004) Other literature indicates 9/10 thromboses secondary to venous thrombus Tobacco use as contribution controversial (4/5 failures in Nahabedian study - venous thrombosis) Venous occlusion, Delayed reconstruction, Hematoma significant factors in breast free tissue recon. (Nahabedian M., et al, 2004) Salvage 50% in breast reconstruction Age, prior irradiation, DM (well-controlled), method of anastomosis, timing, vein graft, and specific arteries/veins not felt to contribute to failure rate

24. Anastomotic Failure--timeline 15-20 minutes <72 hours 5-7 days >8 days Thin vs. thick flaps

25. Thrombus formation Injury to endothelium and media of vessel Mechanical vs. thermal Error in suture placement Backwall or loose sutures Edges not well-aligned (most common in veins�most common site of thrombus) Intimal discontinuity with exposure of media Oblique sutures, large needles, tight knots Infection Hypovolemia and low flow states Nitroprusside at dose to decrease arterial pressure by 30% causes severe reduction in flap blood flow (40%) (Banic, et al. 2003) Vessel geometry (kinking, tension)

26. Vessel spasm Causes Trauma Contact with blood Vasoconstrictive drugs Phenylephrine--dose causing 30% increase in arterial pressure shows no effect on flap circulation (Banic A, et al., 1999) Nicotine Temperature, drying Treatment Warmth Xylocaine Papavarine, thorazine Volume repletion

27. Treatement for anastomotic failure Revision of anastomoses Exploration of wound Streptokinase, urokinase, rt-PA (Atiyeh BS, et al 1999) Leech therapy Wound care Statistics Revisions successful in 50% Revisions less successful after first 24-48hr >6 hrs of ischemia leads to poor survival 12 hrs of ischemia leads to �no-flow� phenomenon After 5 days almost all flaps in rabbit model survived with loss of artery or vein (but not both)�this is rational for other modalities after 48 hours

28. Post-operative care Anticoagulation Attention to wound care Flap monitoring Nothing around neck that might compress pedicle Antibiotics Hemoglobin/intravascular volume�literature unclear (Velanovich V., et al 1988, Quinlan 2003) No pressors/nicotine/cooling of flap (literature unclear)

29. Anticoagulation Rheology RBC concentration Plasma viscosity RBC aggregation RBC deformability Other (platelets, thrombogenic mediators) Agents Aspirin Heparin Dextran Other Indications Hypercoagulable state (Friedman G, et al, 2001) Excessive vessel trauma Complications

30. Dextran Macromolecule which is a compound of glucose subunit Thought to improve RBC flexibility, increase electronegativity of vessel wall (which decreases platelet adhesion), act as intravascular volume expander, decrease RBC aggregation Shown to decrease clotting secondary to exposed collagen in rabbit arteries. Little effect on platelet, rather inhibits fibrin stabilization of thrombi (Weislander, JB, et al., 1986) No effect on overall flap survival when compared with aspirin. Systemic complications 3.9-7.2 times more common with dextran infusion (Disa J., et al, 2001) Complications can include renal damage, anaphylactic shock, congestive heart failure, MI, pulmonary edema, pleural effusion, pneumonia

31. Aspirin Prevent platelet thrombosis Inhibits arachidonic acid to prostaglandin synthesis on the platelet�prevents release of platelet granuoles that cause platelet aggregation. Mechanism is biphasic and dose-dependant High doses of aspirin can have negative effect on endothelial production of prostacyclin which prevents platelet accumulation on exposed collagen and dilates vessels. ASA PR qd x several weeks (often given at beginning of case)�5 grains (325 mg) No good studies to confirm benefit of use Hematoma formation

32. Heparin Naturally occuring glycosoaminoglycan which interrupts clotting cascade Prevents transformation of prothrombin to thrombin, fibrinogen to fibrin Does not lyse existing thrombi Strongly adheres to endothelium Concentration on endothelium 100x serum � life = 90 minutes Given at time of first quarter of arterial anastomoses vs. at time of unclamping (bolus only vs. bolus with drip x 3 days) Literature unconvincing, although it may increase microvascular perfusion after ischemia Hematoma formation Used as irrigation solution Local infusion may possibly be beneficial

33. Low molecular weight heparin Appears to decrease vessel thrombosis in renal transplants (Broyer M, et al.,1991, Alkhunaizi AM, et al, 1998)

34. Flap monitoring Clinical ��flap checks� Most commonly used Warmth Color Pin prick Wound monitoring (hematoma, fistula) Frequency Mechanical Doppler Implanted vs. external vs. color flow Other

35. Clinical flap monitoring Normal exam: Warm, good color, CRT 2-3 seconds, pinprick slightly delayed with bright red blood Venous occlusion (delayed): Edema, mottled/purple/petechiae, tense CRT decreased Pinprick � immediate dark blood, won�t stop Arterial occlusion (usually <72hr): Prolonged CRT, temperature, turgor Pale Pinprick�little bleeding, very delayed

36. Mechanical flap monitoring Doppler External Implanted Buried flaps 80-100% salvage (Disa J, et al 1999) Color flow Other

37. Antibiotics 8-20% of patients undergoing free tissue transfer will develop an infection despite intravenous antibiotic coverage.(Cloke DJ., et al, 2004) 1 day vs. 5 day course of Clindamycin showed no significant difference in free flap survival (Carroll WR., et al., 2003) Topical antibiotics in combination with intervenous antibiotics did not show a significant difference in post-operative complications after free tissue transfer (Simons JP, et al., 2001)

38. Free flap reconstruction�the costs Longer ICU stay, more expensive, longer OR time (McCrory AL, et al., 2002)

44. Sources Broyer M, Gagnadoux MF, Sierro A, Fischer AM, Niaudet P. Preventive treatment of vascular thrombosis after kidney transplantation in children with low molecular weight heparin. Transplant Proc 1991; 23: 1384. Alkhunaizi AM, Olyaei AJ, Barry JM, et al. Efficacy and safety of low molecular weight heparin in renal transplantation. Transplantation 1998; 66: 533. Nahabedian MY. Singh N. Deune EG. Silverman R. Tufaro AP. Recipient vessel analysis for microvascular reconstruction of the head and neck. [Journal Article] Annals of Plastic Surgery. 52(2):148-55; discussion 156-7, 2004 Feb. McCrory AL. Magnuson JS. Free tissue transfer versus pedicled flap in head and neck reconstruction. [Journal Article] Laryngoscope. 112(12):2161-5, 2002 Dec. Kroll SS. Robb GL. Reece GP. Miller MJ. Evans GR. Baldwin BJ. Wang B. Schusterman MA. Does prior irradiation increase the risk of total or partial free-flap loss?. [Journal Article] Journal of Reconstructive Microsurgery. 14(4):263-8, 1998 May. Jones NF. Johnson JT. Shestak KC. Myers EN. Swartz WM. Microsurgical reconstruction of the head and neck: interdisciplinary collaboration between head and neck surgeons and plastic surgeons in 305 cases. [Journal Article] Annals of Plastic Surgery. 36(1):37-43, 1996 Jan. Foote RL. Olsen KD. Meland NB. Schaid DJ. Kunselman SM. Tumor-ablative surgery, microvascular free tissue transfer reconstruction, and postoperative radiation therapy for advanced head and neck cancer. [Journal Article] Mayo Clinic Proceedings. 69(2):122-30, 1994 Feb. Cloke DJ. Green JE. Khan AL. Hodgkinson PD. McLean NR. Factors influencing the development of wound infection following free-flap reconstruction for intra-oral cancer. [Journal Article] British Journal of Plastic Surgery. 57(6):556-60, 2004 Sep.

45. Sources Braun S. Mine R. Syed SA., et al. The optimal sequence of microvascular repair during prolonged clamping in free flap transfer. Plastic and Reconstructive Surgery 111(1):233-241, 2003 Banic A. Krejci V. Erni D., et al. Effects of sodium nitroprusside and phenylephrine on blood flow in free musculocutaneous flaps during general anesthesia. Anesthesiology 90(1):147-155, 1999 German G. Steinau HU. The clinical reliability of vein grafts in free flap transfer. Journal of Reconstructive Surgery 67:194-199, 1996 Nahabedian MY. Bahram M. Manson PN. Factors associated with anastomotic failure after microvascular reconstruction of the breast. Plastic and Reconstructive Surgery 114(1):74-82, 2004 Nahabedian M. Singh N. Deune EG. Recipient vessel analysis for microvascular reconstruction of the head and neck. Annals of Plastic Surgery 52(2):148-155, 2004 Disa JJ. Polvora VP. Pusic AL Singh B. Cordeiro P. Dextran-related complications in head and neck microsurgery: Do the benefits outweigh the risks? A prospective randomized analysis. Head and Neck Microsurgery 112(6):1534-1539, 2001 Carroll WR. Rosenstiel D. Fix JR. de la Torre J. Solomon JS. Brodish B. Rosenthal EL. Heinz T. Niwas S. Peters GE. Three-dose vs extended-course clindamycin prophylaxis for free-flap reconstruction of the head and neck. [Clinical Trial. Journal Article. Randomized Controlled Trial] Archives of Otolaryngology -- Head & Neck Surgery. 129(7):771-4, 2003 Jul. Simons JP. Johnson JT. Yu VL. Vickers RM. Gooding WE. Myers EN. Pou AM. Wagner RL. Grandis JR. The role of topical antibiotic prophylaxis in patients undergoing contaminated head and neck surgery with flap reconstruction. [Clinical Trial. Journal Article. Randomized Controlled Trial] Laryngoscope. 111(2):329-35, 2001 Feb.

46. Sources Shindo M., Costantino P., Nalbone V., et al., Use of a mechanical microvascular anastomotic device in head and neck free tissue transfer. Archives of Otolaryngology�Head & Neck Surgery 122(5):529-532, 1996. De Lorenzi F., van der Hulst R., Boeckx W., et al., VCS auto suture stapled microvascular anastomoses in lower leg free flaps. Plastic and Reconstructive Surgery 109(6):2023-2030, 2002 DeLacure M., Kuriakose M., Spies A., et al., Clinical experience in end-to-side venous anastomoses with a microvascular anastomotic coupling device in head and neck reconstruction. Archives of Otolaryngology�Head and Neck Surgery 125(8):869-872, 1999 Ahn C., Shaw W., Berns S., et al., Clinical experience with the 3M microvascular coupling anastomotic device in 100 free-tissue transfers. Plastics and Reconstructive Surgery 93:1481-1484, 1994 Berggren A., Ostrup L., Lidman D., et al., Mechanical anastomosis of small arteries and veins with the Unilink apparatus: a histologic and scanning electron microscopic study. Plastic and Reconstructive Surgery, 80:274-283, 1987 Swartz W., Banis J., Head and Neck Microsurgery. Williams & Wilkins, Baltimore, MA, c.1992 Baker S. Microsurgical Reconstruction of the Head and Neck. Churchill Livingstone, New York, NY, c.1989 Panje W., Moran W. Free Flap Reconstruction of the Head and Neck. Thieme Medical Publishers, Inc., New York, NY c.1989 Velanovich V. Smith DJ. Robson MC. Heggers JP. The effect of hemoglobin and hematocrit levels on free flap survival. American Surgeon 54(11):659-663, 1988 Quinlan J. Anaesthesia for reconstructive free flap surgery. Anesthesia and Intensive Care Medicine The Medicine Publishing Company, Ltd., c.2003