Principles of Microvascular Surgery.

Principles of 

Microvascular Surgery. 

Arik Zaretski M.D. 

Department of Plastic Surgery 

Tel-Aviv Sourasky Medical Center. 

History 

• In the late 1890’s and early 1900’s - 

» surgeons began approximating blood vessels. 

» Laboratory animals and humans. 

» No magnification. 

• Hallowell, 1759 - repair of the brachial artery by 

hand suture. 

• J.B. Murphy, 1897 - described the first vascular 

anastomosis. 

• Alexis Carrel, 1902 - the triangulation method in 

end-to-end anastomosis in animals. 

1

History 

• Zachariah Janssen, 1590 - 

invention of the compound 

microscope. 

• Nylen, 1921 - first clinical 

application of monocular 

operating microscope - for 

human eardrum surgery. 

• Halmgren, 1921 - 

stereoscopical microscope 

for otolaryngological 

procedures. 

History 

• Perritt, 1950 - microsurgery in clinical 

ophthalmology. 

• Kurze, 1957 - microsurgery in neurosurgery. 

• Jacobson & Suarez, 1960 - microsurgical 

anastomosis in carotid arteries (1.4mm) of 

laboratory animals with 100% patency rate. 

• Jacobson, 1965 - vessels 1mm in diameter with 

100% patency. 

• Green, 1966 - used 9-0 nylon suture on rat aortas 

(1.3mm) & vena cavas (2.7mm) with patency of 37 

out of 40 animals at 21 days. 

2

History 

• Malt & McKhann, 1962 - the first successful 

clinical replantation - 2 patients with arm 

amputations. 

• Chinese surgeons, 1963 - successful replantation 

of a hand amputated at the wrist. 

• kleinert & kasdan, 1963 - revascularized near 

amputated digits. 

» Loupe magnification. 

» Vain grafts. 

History 

• Nakayama, Surgery 1964 - The first clinical series 

of free tissue microsurgical transfers - cervical 

esophageal reconstruction with vascularized 

intestinal segments in 21 patients. 

• Buncke & Schulz, PRS 1965 - experimental 

replantation of rabbit ears and monkey digits. 

3

History 

• Komatsu & Tamai, PRS 1968 - first successful 

replantation of completely amputated digit. 

» Used surgical microscope. 

History 

• Krizek, PRS 1968 - first successful series of free 

flap transfers in a dog model. 

• Cobbett, J Bone Joint Surg 1968 - transferred a 

great toe to the hand. 

• Antia & Buch, Br J Plast Surg 1971 - superficial 

epigastric artery free flap (skin and fat) to fill a 

soft-tissue defect in the cheek. 

• McLean & Bunke, PRS 1971 - omental free flap for 

large scalp defect. 

4

History 

• Danil & Taylor + O’brien, PRS 1973 - free groin 

flaps for lower extremity reconstruction. 

• Since the early 1970’s: 

» More donor sites. 

History 

» Refinement in microvascular tools and techniques. 

» Microsurgery became more prevalent. 

» Rapid gain of clinical experience. 

Improved results - better than 90% in most 

series. 

5

History 

• Khouri, 1992 - review of the clinical experience of 

9 microsurgens. 

• Khouri found that: 

History 

» “Operative experience is the single most critical 

factor related to improved success rates…” 

6

Basic Science Concepts in 

Microsurgery 

• Vessel injury, repair and regeneration. 

• Process of vasospasm and thrombosis. 

» Pharmacological control. 

• Effects ischemia and hypoxia on revscularized 

tissue. 

• Three basic layers: 

Vessel Anatomy 

» Intima - endothelial lining. 

» Media - smooth muscle. 

» Adventitia - outer connective tissue. 

7

Artery 

and vein 

Vein 

Vessel Injury and Regeneration 

• The beginning steps in the formation of a 

thrombotic plug: 

» Exposure of the subendothelium to the bloodstream. 

» Platelet aggregation. 

• The collagen (media and adventitia) stimulates 

platelet clumping. 

• Microvascular anastomoses can disturbs the 

endothelium and subendothelium. 

8

Vessel Injury and Regeneration 

• Weinstein, 1979 - full thickness sutures: 

» offer intimal continuity. 

» Less amount of anastomotic bleeding. 

» Less platelet aggregation. 

• Harashima, PRS 1976 - no difference in patency 

(94%) between adventitial or full thickness 

sutures. 

First day 

Group A Group B 

X100 X100 

9

Group B 

5th day 7th day 

Group A 

X300 

Two weeks 

X300 

Group B 

X100 

X100 

10

Vessel Wall Healing 

• At the time of the anastomosis - a layer of platelet 

covers the denuded endothelium. 

• Next 24-72 h - platelets gradually disappear. 

• Pseudointima forms within 5 days. 

• After 1 - 2 weeks - new endothelium covers the 

anastomotic site. 

• The elastic and muscular layers rarely return to 

their preinjury state. 

The critical period of thrombus formation 

is the first 3-5 days. 

Vessel Regeneration 

• Only the endothelial layer is damaged - 

reconstituted from surrounding cells, 7-10 days. 

• Damage to subendothelial structures - 

regeneration of epithelium by migration and 

differentiation of myoendothelial cells from the 

cut vessel ends. 

• Regeneration of other layers - proliferation of 

fibroblasts, collagen and myointimal thickening at 

the anastomotic site. 

11

Endothelial Damage 

• Margic, PRS 1985 - dissection and exposure of 

vessels from their beds. 

• Bipolar coagulation too close to the branch 

origin. 

• Dryness - exposed vessels should be kept in 

moist environment. 

• Prolonged vasospasm, more then 2h. 

• Injury from microvascular clips. 

• Needles and suture penetration + technique of 

placement. 

Injury from microvascular clips 

• Directly related to clip pressure. 

• Curved or angled clip cause more damage than 

flat clip. 

• Closing pressures should remain below 30 

gr/mm 2 . 

Balloons 

Granulocyte 

Crater-like defect 

12

Damage from needles, sutures and technique 

• Large needles, obliquely placed sutured - 

» Endothelial lacerations. 

» Exposing subendothelium. 

» Platelet aggregation. 

• Repeat needle puncture - 

» Bleeding. 

» Large platelet plugs. 

• Unequal distances between sutures - 

» Endothelial gaps, distortion, constriction. 

» Exposure of intimal flaps. 


• Loosely tied sutures - 

» Exposure of sub endothelial elements. 

» Excessive anastomotic bleeding. 

» Platelet plug formation. 

• Too many sutures or sutures tied too tightly - 

» Endothelial slough. 

• Excessive trauma to vessel walls, tension and 

loosely approximation - 

» Medial discontinuity. 

» Pseudoaneurysms. 

13


• Chow, Br J plast surg 1982 - found greater 

tolerance for microanastomotic tension. 

• Acland & Trachtenberg, PRS 1977 - used SEM to 

evaluate microanastomoses, found 100% patency 

rate despite: 

» Intimal loss below the site of clamp pressure. 

» Medial necrosis at the site of the anastomosis. 

Some tissue damage is tolerated. 

Local factors 

• Lidman & Daniel, Ann Plast Surg 1981- 

» Anastomoses preformed in the zone of injury. 

» External compression of the anastomosis by 

hematoma, tight wound closure, swelling. 

14

The clotting mechanism 

• Platelets do not adhere to undamaged, healthy 

intimal surfaces. 

• Intimal injury - exposed collagen - platelet 

adhesion to the vessel surfaces. 

• Platelet activation. 

• Release of platelet granules. 

• Attract more platelet = aggregation. 

1 


• The activated platelet stimulates receptor site to 

which fibrinogen adheres. 

• Fibrinogen forms proteinaceous bridges between 

platelets. 

• Activated platelet - promote 

the change of fibrinogen to 

fibrin. 

• Fibrin promotes the “red clot” 

formation. 

2 

15


• Platelet contain 2 types of granules, contribute to 

platelet recruitment: 

» Alpha granules - 

• Von Willebrand factor. 

• Fibrinogen. 

» Dense granules - 

• ADP. 

• Calcium ions. 

• Serotonin. 

• When platelet aggregation reach a critical mass 

that causes thrombus formation by: 

» occluding the vessel, or- 

» Initiation of the classic extrinsic pathway of coagulation 

Antithrombotic therapy 

Heparin 

• Increases the action of antithrombin3 -inactivates 

thrombin. 

• Decrease platelet adhesion. 

• Decrease the conversion of fibrinogen to fibrin. 

» Greenberg, Masem and May, PRS 1988 - in a rabbit 

model, low dose heparin infusion significantly 

prevented anastomotic occlusion for 72 hours. 

» Khouri, PRS 1990 - single bolus of heparin given 

before blood flow was reestablished inhibited thrombus 

formation - preventing the conversion of fibrinogen to 

fibrin. 

16


Heparin (cont.) 

• Complications - hematoma formation, in animals 

12.5% (3 of 24). 

• Clinically - heparin is given to save free flaps. 

• Others - Johnson PC, PRS 1990 - heparin dose 

not improve the patency in uncomplicated repairs 

and increases the risk of bleeding. 


• Khouri, PRS 1998 - 

Heparin (cont.) 

» total of 493 free flaps preformed by 23 members of the 

International Microvascular Research Group in a 

prospective study. 

» The use of heparin solution for luminal irrigation had no 

apparent effect on thrombosis or failure. 

» Only subcutaneous heparin given post operatively had 

a significant effect - lower occurrence of postoperative 

thrombosis. 

17


Aspirin 

• Administered in low doses - 0.1 mM (325mg - PO). 

• Inhibits initial platelet aggregation at the 

anastomotic site. 

• Inhibits cyclooxygenase - blockage of 

thromboxane A2. 

• Even at low doses - some inhibition of the release 

of prostacyclin (a potent vasodilator and platelet 

inhibitor). 


• Polysaccharide, molecular weights of: 40,000 or 

70,000. 

• Volume expander. 

• Antiplatelet. 

• Antifibrin. 

» Explanations: 

Dextran 

• raising of negative electrical charge on platelets. 

• Inactivation of von Willebrand factor. 

• Rothkopf, PRS 93 - patency of 85% in the dextran 

group and 48% in controls. 

18


Low molecular weight heparin 

• Ritter, J Reconstr Microsurg 1998 - 

» Anti factor 10a. 

» 66 epigastric free flap in rats. 

» Anastomotic patency was significantly improved . 

» Total tissue survival area was improved. 

» LMWH - improved anastomotic patency while 

minimizing hemorrhage. 


Proteolytic enzymes - Streptokinase & Urokinase 

• Streptokinase - produced by group C beta 

hemolytic streptococci. 

• Urokinase - produced by human kidney cells. 

• Both convert plasminogen into plasmin, a highly 

specific fibrinolytic enzyme. 

• Goldberg, J Reconst Microsurg 1989 - salvage of 

6 of 7 thrombosed free flaps vessels ( subflap 

hematoma in 1 case). 

19


Tissue plasminogen activator (tPA) 

• Produced by human vascular endothelium. 

• Activates plasminogen (inactive precursor to 

plasmin). 

• Levy, J Reconst Microsurg 1991 - no difference 

between tPA and urokinase in the rat model. 

• Others report cases of free flap salvage with tPA 

infusion - Fedem & Walton, J Reconst Microsurg 

1989. Arnljots, PRS 1992. Romano, 1991. 

• Reports on selective tPA infusion. 


• Davies, Br J Plast Surg 1982 - surveyed the use of 

anticoagulation in clinical microsurgery. 

» 73 centers in 22 countries. 

» Found equal success rates (89%) for free flaps with 

anticoagulation (n=691) and flaps without 

anticoagulation (n=134). 

» For limb replantation - success rat was lower with 

anticoagulation (76%) than without (89%). 

20


conclusions: 

• No definite indications when mechanical and 

vascular factors are optimal. 

• When there is thrombosis in the post operative 

period - flap reexploration and treatment with 

fibrinolytic and/or anticoagulation therapy. 

• Anticoagulation or fibrinolytic therapy may be 

indicated where mechanical or metabolic factors 

are not favorable and cannot be improved. 

Tissue response to ischemia and hypoxia 

• Free tissue transfer requires a period of tolerance 

to ischemia by the donor tissue. 

• Skin and subcutis are relatively resistant to 

anoxia - 

» Intracellular pH changes - reversible up to 24h. 

• Mammalian skeletal muscle - 

» much less tolerance to ischemia. 

» Irreversible damage to energy metabolism - 4h. 

» Irreversible damage starts at 6 hours. 

• Connective tissue (fibroblast, chondroblast, 

osteoblast) relatively resistant to hypoxia. 

21


• Cooling prolongs tolerance to ischemia in all 

types of tissues. 

» Donski, Br J Plast Surg 1980 - effect of cooling on 

groin flaps in rabbit - 86% survival after cooling for 1-3 

days. 

» Anderl, 1977 - stored a human groin flap for 24h. 

» Cooley, J Microsurg 1981 - in rats, max ischemia 6h at 

body temp and 48h if cooled. 

» Walkinshaw, PRS 1988 - proximal bowel segments 

are more resistant to warm ischemia at 2h. 


Tissue Warm Cold 

Skin & subcutaneous t. 4-6h Up to 12h 

Muscle

The no-reflow effect 

• Ames, Am J Pathol 1968 - studied the effect of 

ischemia on rabbit brains. 

» Some ischemic organs failed to reperfuse after their 

blood supply was reestablished. 

» Called this - the no-reflow phenomenon. 

• Mechanism - 

» Cellular swelling in the vascular endothelium. 

» Intravascular platelet aggregation. 

» Leakage of intravascular fluid to the interstitial space. 

• Clinical observations - 


» Excellent blood flow immediately after anastomosis. 

» Decrease in blood flow shortly after. 

» The low flow state triggers intravascular thrombosis. 

» Flap ischemia. 

• May, PRS 1978 - no-reflow in groin flap in rabbits- 

» Mild obstruction to blood flow 1h post ischemia. 

» Increasing severity at 8 and 12h. 

» Histologic changes reversible at 4 and 8h. 

23


• Zdeblick, J Hand Surg 1985 - no-reflow in rat hind 

limbs. 

» Predictors - 

• RBC aggregates 5min after replantation. 

• Tissue pH change persisting for 1h or more 

postreplantation. 

» Mechanism - 

• Ongoing arterial obstruction. 

• AV shunting. 

• Altered thrombogenic / fibrinolitic system. 

• Jacobs, PRS 1981 - 


» relationship between warm ischemia time and 

fibrinolitic activity. 

» Greatest drop in fibrinolysis - 0-6h of warm ischemia. 

• Suval, J Surg Res 1987 - 

» Changes in microvascular permeability in reperfusion 

after 30min or 2h of ischemia. 

» First manifestation of tissue damage in reperfusion 

injury - d/t leukocytic and endothelial cell interaction. 

» The no-reflow - in 30% of muscle tissue regardless of 

ischemia time. 

24

• Treatment - 


» Reports of flaps salvage with thrombolytic drugs. 

» Nonsteroidal antiinflamatory agents - inhibit 

cyclooxygenase - blocks thromboxane A2 

(vasoconstriction and thrombus formation). 

• Douglas, PRS 1987 - ibuprofen treated flaps survive 

longer periods of ischemia. 

• Accelerated fluorescein uptake - reversal of thrombosis 

and vasoconstriction. 

Flap failure - summary 

• Endothelial disruption. 

• Exposure of subendothelial collagen. 

• Platelet adherence and aggregation. 

• When critical mass - trigger of fibrin deposition. 

• Vasospasm. 

• Stenosis. 

• Thrombosis of the vessel. 

• Blood flow falls. 

• When critical level - flap failure. 

25

• Instruments. 

• Sutures. 

TECHNICAL FACTORS 

• Type of anastomoses. 

• Technique of anastomosis. 

Instruments and sutures 

• Loupes or operating microscope? 

• Loupes - 

» Shenaq, Klebuc and Vargo, PRS 1995 - 8 year 

experience. 251 free flaps with 5.5X loupes - 

• 97.2% successful. 

• Partial flap necrosis - 1.2%. 

• Revision 8.3%. 

• Free flap 98.5%, toe-to-hand 96.4%, digital replantation 

79.2%. 

• Good for vessels > 1mm. 

• Cost effective, portable, operator freedom. 

26

• Loupes… 

• Or microscope? 

Microsugical instruments 

• “few in number and high in quality”. 

27

• The number is critical!!! 

Number of sutures 

» Too few - excessive bleeding and thrombus formation. 

» Too many - increased damage to the endothelium. 

• The goal - well approximated, sealed, 

nonbleeding union with a minimum number of 

sutures. 

• Cohen, PRS - 1979 - in rat femoral vessels 8- 

suture anastomosis is optimal. 

Type of sutures 

• Absorbable and nonabsorbale. 

• Mii, J Microsurg 1980 - smoother endothelial 

regeneration with polyglycolic acid sutures than 

with nonabsorbale material. 

• Thiede, J Microsurg 1979 - no increased 

aneurysm or pseudoaneurysm formation and no 

vascular raptures d/t decreased mechanical 

endurance with polyglycolic acid or polyglactin 

sutures. 

• Most surgeons use nonabsorable sutures - nylon 

or prolene. 

28

• Key sutures - 

Anastomotic technique 

» Carrel’s triangulation method- 120°. 

» 180° halving sutures. 

Interrupted or continuous sutures? 

• Simple interrupted full thickness 

sutures are preferred and are the 

standard to which all techniques 

are compared. 

• Continuous sutures - 

» Same patency rate. 

» Faster. 

» May narrow the caliber of the 

vessel lumen. 

» Cordeiro, Ann Plast Surg 1998 

- continuous suture 

anastomosis in 200 consecutive 

free flap - similar success rate. 

29

Interrupted or continuous sutures? 

• The sleeve technique - 

» Originally described by Lauritzen, 

Scan PRS 1980 - 

» Said to be: 

• faster, Simpler. 

• Suture cause less trauma to the 

vessels. 

• Less intraluminal suture exposure. 

• Lauritzen: “ endothelialization in 

haft the time”. 

» Clinically: 

• Difficult in veins. 

• Reports of stenosis, thrombus and 

aneurysm formation. 

• Sully, PRS 1982 - lower patency 

rate - 84% (normal - 98%). 

• O’Brien - “not superior in clinical 

situation”. 

End-to-end, end-to-side anastomosis 

• End-to-end anastomosis - 

» The most common type. 

» Size discrepancy up to 2:1. 

• End-to-side anastomosis - 

» when size discrepancy more then 2:1. 

» When limb or organ depends on a 

single vessel for perfusion. 

30

End-to-end, end-to-side and end-in-end 

• End-to-side anastomosis - 

» Godina, PRS 1979 - 

• higher failure rate with end-toend 

anastomosis. 

• End-to-side - choice for lower 

extremity free flaps. 

» Samaha, PRS 1997 - 

• no differences in patency rates 

in 1051 free flaps. 

» Animal experiments - 

• No difference in patency. 

• When different size - end-toside 

is better. 

• Flow dynamics in end-to-side 

are favorable. 

Stapling technique - anastomotic 

coupling systems 

• Nakayama, Surgery 1962 - the first ring device. 

• Ostrup & Berggren, Ann Plast Surg 1986 - 

modification, evolved into 3M microvascular 

anastomotic coupler. 

31

Stapling technique - anastomotic 

coupling systems 

• Clinical series - 

» Equal or greater patency 

rates. 

» Considerably faster. 

» Blair, Microsurgery 1989 - 

Histology - similar healing 

process. 

» Gilbert, Microsurgery 1989 - 

At 16 weeks postrepair 

coupled anastomoses are 

50% stronger. 

Nonpenetrating microvascular stapling device 

• Yamamoto, Ann Plast Surg 1999 - 

32

Laser anastomosis 

• Various experimental models and few clinical 

series. 

» Patency rate favorable. 

» Shorter operating time. 

» Limited endothelial trauma. 

» No suture material to induce foreign body reaction. 


• Wide rang of laser wavelengths - 

CO2, argon, neodymium:YAG, KPT 

and diode lasers. 

• Mechanism - still undefined. 

• Initial strength - physical factors 

(collagen coiling, crosslinking) not 

biological processes (inflammation 

and healing). 

33


• Tissue welding may be d/t simply heat generated 

by the laser energy or wavelength dependent. 

• The us of photosensitizing dyes makes low 

energy discharges possible - minimal collateral 

tissue damage. 

• To date - still investigational - 

» Aneurysm formation. 

» Low breaking and tensile 

strength in the early post 

operative period. 

» Cost. 

Monitoring perfusion 

• Free flap success is enhanced by the rapid 

identification and salvage of failing flaps. 

• Clinical assessment - 

» Skin color. 

» Temperature. 

» Capillary refill 

» Pinprick testing. 

• Devices to monitor blood flow should be - 

» highly reliable. 

» Simple to operate and interpret. 

» Inexpensive. 

34


• Doppler ultrasound flowmeter - 

» The most common. 

» Arterial + venous flow. 

• Laser Doppler - 


» Helium neon laser, penetrate 1.5mm, 

some light will be reflected by RBC 

moving in the capillaries in 1mm 3 of 

tissue. 

» Continuously record the microcirculatory 

flow in all type of cutaneous and 

musculocutaneous free flaps. 

» Walkinshaw, Ann Plast Surg 1987 - 

• Unable to predict future clinical events. 

• No more accurate than clinical 

assessment in pointing the need for 

intervention. 

35


• Temperature monitoring - 

» First described by Baudet, PRS 1976. 

» Good for skin or skin island flaps. 

» Unreliable in free muscle flaps. 

» Khouri & Shaw, PRS 1992 - 

• Series of 600 consecutive free flaps. 

• Monitored the temp difference between the flap and a 

control site. 

• Detected 52 thrombosed flaps - 45 salvaged. 

» Jones, PRS 1992 - 

• Pulse oxymeter is better for replanted digit. 

• Good only for skin that can be monitored more easily by 

capillary refill and Doppler probes. 


• Implantable ultrasonic Doppler - 

» Direct monitoring. 

» Distinguish between arterial and 

venous occlusion. 

» More reliable than thermocouple 

probe. 

» Disa, Cordiero & Hidalgo, PRS 

1999 - 

• 750 free flaps, 673 nonburied. 

• Flap loss - 2.3%. 

• Buried flap loss - 6.5%, non were 

salvaged in reexploration. 

• The use of Implantable Doppler is 

recommended in buried flaps. 

36

The influence of patient factors 

• Tobacco use - 

» Cigarette smoking affect - 

• Cutaneous blood flow. 

• Wound healing. 

• Survival of pedicaled flaps. 

» Byproducts of cigarette smoke produce a 

thrombogenic state and vasoconstricting effect. 

» Large clinical series failed to show any damaging effect 

of cigarette smoking on free tissue transfer. 

» Reus, PRS 1992 - no difference in patency in 162 free 

flaps. 

» Buncke, J Reconstr Microsurgery 1996 - 

• 963 free flaps. 

• No survival or patency difference. 

• In smokers - higher incidence of healing complications at 

the flap interface or donor-site. 

The influence of patient factors 

» Cigarette smoking adversely affect the outcome of 

digital replantation. 

» Blondeel, Br J Plast Surg 1999 - large series - 100 

free DIEP flaps for breast reconstruction - smoking was 

found to be a risk factor. 

37

Microanastomoses to irradiated vessels 

• Radiotherapy is known to impair wound healing - 

» decreasing the number of blood vessels. 

» Tissue ischemia. 

» Decreasing fibroblast proliferation and collagen 

production. 

• In earlier studies - patency was significantly lower 

in irradiated vessels. 

• Mulholland, PRS 1993 - similar failure rates in 226 

irradiated and in 108 nonirradiated. 

• Schusterman, PRS 1994 - large clinical series in 

prior radiotherapy do not predispose to a higher 

rate of acute flap loss or wound complications. 

Microanastomoses to irradiated vessels 

• Kroll, PRS 1996 - 854 consecutive free flaps - no 

effect to previous irradiation. 

• Guelincks, PRS 1984 - 

» limit dissection to recipient vessels. 

» Restrict electrocoagulation of arterial side branches. 

» Use small gauge needles. 

» Pass the needle from inside to outside. 

» Shorten the period of vessel cross clamping. 

» Flush vessels in heparinized solution. 

38

Free flaps 

• Twenty years ago - free tissue transfer was in the 

hands of few pioneers. 

• 10 years ago - primarily practiced at university 

centers. 

• Today - 

» free flap surgery is performed at an increasing rate and 

for expanding indications. 

» Free flaps in more difficult situations - 

• Irradiated fields. 

• Elderly patients. 

• Occlusive peripherovascular disease of lower extremity 

from arteriosclerosis or diabetes mellitus. 

• Success rates - 

Free flaps 

» 10 years ago - 90 - 94%, with 10% incidence of 

thrombosis. 

» Khouri, PRS 1998 - in data from 9 microsurgical 

centers - 

• The success rate was 98.8% 

• Only 3.7% of flaps were reexplored for thrombosis. 

• Today - microsurgery is more than just to cover 

the wound - an esthetic final result is what most 

plastic surgeons currently strive for. 

39

Free flaps 

Free flaps 

• Failure of free tissue transfers - 

• Most often due to technical factors. 

• Khouri, PRS 1998 - 

» Most of the complications occurred in post traumatic 

reconstructions. 

» The magnitude of the traumatic insult is the single 

most important factor. 

» One should always seek the vascular pedicle of largest 

diameter - failures are high when small diameter 

pedicles are used, especially if ,1mm. 

40

• Free groin flap - 

Free flaps - skin 

» Superficial circumflex iliac a+v. 

» Concealment of the donor 

deformity. 

» Donor site - closed primarily. 

» Non hair bearing flap. 

» Short donor pedicle. 

» Arterial anomaly's. 

» Small external diameter 0.8- 

1.8mm. 

» Flap morbidity 15-20%. 


• Free radial forearm flap - 

» Radial a, cephalic/basilic v. 

» The most common and versatile 

skin flap. 

» Head and neck reconstructions. 

» Thin flap. 

» Osseous segment. 

» Long vascular pedicle, up to 

20cm. 

» Can be sensate flap. 

» Skin graft to donor site. 

» Donor site morbidity. 

41

• Free scapular flap - 

» Circumflex scapular a+v. 


» long vascular pedicle 6-14cm, 

arterial diameter 1.5-4.5mm. 

» Large flap. 

» Donor site closed primarily (up to 

9-10cm) - min morbidity. 

» Elevation - rapid and easy. 

» Nonsansate flap. 

» Thickness is variable (1.5-3cm). 

» Positioning the patient in lateral 

decubitus position. 

• Free parascpular flap - 

» Terminal branch of the 

descending circumflex 

scapular artery. 

» May be combined with the 

scapular flap. 


42

Free flaps - fascia 

• Useful where thin, well 

vascularized cover is needed. 

• Can provide unrestricted 

gliding of tendons in the hand. 

• Free temporoparietalis 

fascial flap - 

» Superficial temporal artery +v. 

Free flaps - muscle 

• Tamai, PRS 1970 - first report of free muscle 

transfer - rectus femoris muscle transfer in dogs. 

• Harii, Ohmori & Torii, PRS 1973 - free gracilis 

muscle for facial reanimation. 

• Surgical team in china - the lateral portion of the 

pectoralis major muscle to the forearm. 

• A common operation in plastic surgery. 

• The majority are to bring bulk of soft tissue cover 

in traumatic losses, oncologic resections or 

osteomyelitis. 

43

• The most common - 


» Latissimus dorsi and Rectus abdominis. 

• Reliable. 

• Large caliber. 

• Long vascular pedicles. 

• Relatively low donor site morbidity. 

• Histology - muscle fibers that are not reinnervted 

gradually degenerate and eventually replaced by 

fat cells. 

• Functional muscles - 


» transfer of skeletal muscle by microvascular 

anastomosis + reinervation by microsurgical technique. 

» The working strength of a skeletal muscle is directly 

proportional to the cross-section area of the contracting 

muscle fibers. 

» The range of muscle contraction is a factor of fiber 

length. 

» The donor muscle nerve should match the anatomy of 

the recipient nerve as possible. 

» Terzis, J Hand Surg 1978 - in rabbit rectus femoris - 

despite 100% patency of the anastomosis, only 25% 

working capacity. 

» Importance of reestablishing correct resting tension. 

44


• Free latissimus dorsi muscle 

flap - 

» Thoracodorsal system. 

» The most common donor site. 

» Large - good for extensive defects. 

» Good for contaminated wounds. 

» Augments blood supply to areas of 

deficiency. 

» Long and constant vascular pedicle - 

good for lower extremity. 

» Can be mayocutaneous. 

» Low donor site morbidity. 

• Free latissimus dorsi 

muscle flap - 

» Disadvantages - 

• Loss of functional 

motor unit - minimal 

effect on healthy 

patient. 

• Scar. 


• Seroma at donor site. 

• Some winging of the 

scapula. 

45

Free flaps - osseous / osseocutaneous 

• First transfer - Ostrup & Friedrickson, PRS 1974 - 

• Buncke, PRS 1977 - free rib osseocutaneous flap 

to lower leg for tibial pseudoarthrosis. 

• Serafin, Br J Plast Surg 1977 - rib 

osseocutaneous flap for mandibular 

reconstruction. 

• Taylor, 1979 - first to report the free fibula flap. 

• Taylor, PRS 1978 - free iliac crest flap. 

Free flaps - osseous / osseocutaneous 

• The free fibula flap - 

» Peroneal vessels a+v. 

» Up to 26cm of vascularized cortical bone. 

» Blood supply - endosteal + musculoperiosteal. 

» Good for reconstruction of - femor, tibia, humerus, 

radius and ulna that are not amenable to grafting by 

conventional nonvascularized bone graft. 

» Mandibular reconstruction. 

» Cortical bone - stress and weight bearing. 

» The epiphysis of the fibular head supplied by branches 

of the tibial artery. 

46

Free fibula flap 

47

... 

הדות 

48

Principles of Microvascular Surgery.

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