Microvascular Free Tissue

Transfer Glen T. Porter, MD

Faculty Advisor: Shawn D. Newlands, MD, PhD

The University of Texas Medical Branch

Department of Otolaryngology

Galveston, Texas

Grand Rounds Presentation

October 2004

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

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

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

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

Recipient vessels

Veins

External jugular

Branches of internal jugular

(common facial)

Internal jugular

Retrograde (superficial

temporal, thyroid)

Transverse cervical, occipital

(very small)

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)

Vessel selection

Size

Arterial vs.Venous

Atherosclerosis

XRT-related changes

Vessel geometry (location and

orientation)

Vessel length

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

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)

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

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 ½ times normal –paralyses smooth muscle)

Chemical dilation, if necessary

Suturing

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

3 suture

technique

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

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

End-to-side

Anastomosis

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

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)

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

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

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

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

Anastomotic Failure--timeline

15-20 minutes

<72 hours

5-7 days

>8 days

Thin vs. thick flaps

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)

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

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

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)

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

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

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

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

½ 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

Low molecular weight heparin

Appears to decrease vessel thrombosis in renal

transplants (Broyer M, et al.,1991, Alkhunaizi AM,

et al, 1998)

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

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

Mechanical flap monitoring

Doppler

External

Implanted

Buried flaps

80-100% salvage (Disa J, et al 1999)

Color flow

Other

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)

Free flap reconstruction—the costs

Longer ICU stay, more expensive,

longer OR time (McCrory AL, et al.,

2002)

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.

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.

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

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