principles of microvascular surgery

PRINCIPLES OFPRINCIPLES OF
MICROVASCULAMICROVASCULA
R SURGERYR SURGERY
-Dr.sumer yadav-Dr.sumer yadav
dr sumer yadav (mch plastic and reconstructive
surgery); sumeryadav2004@gmail.com

INTRODUCTIONINTRODUCTION
►MICROSCOPEMICROSCOPE
MICROSURGERYMICROSURGERY
MICROVASCULAR SURGERYMICROVASCULAR SURGERY
RECONSTRUCTIVERECONSTRUCTIVE
MICROSURGERYMICROSURGERY

HISTORYHISTORY
►1590- Invention of compound microscope1590- Invention of compound microscope
by Zacharia Janseenby Zacharia Janseen
►1897- First vascular anastomosis by1897- First vascular anastomosis by
J.B.MurphyJ.B.Murphy
►1902- End to end anastomosis by 3-stay1902- End to end anastomosis by 3-stay
suture technique by Alexis Carrelsuture technique by Alexis Carrel
►1965- First digital replantation by Tamai1965- First digital replantation by Tamai
►1968- First successful toe to thumb transfer1968- First successful toe to thumb transfer
by Cobbettby Cobbett

►1968- First free flap in Bombay,India by1968- First free flap in Bombay,India by
Antia and Buch(Use of dermatolipomatousAntia and Buch(Use of dermatolipomatous
groin flap to fill a facial defect)groin flap to fill a facial defect)
►1970- First completely successful free flap1970- First completely successful free flap
operation in Oakland,California by Mcleanoperation in Oakland,California by Mclean
and Bunckeand Buncke
►1973- First composite flap (groin flap) by1973- First composite flap (groin flap) by
DanielDaniel

TOOLS IN MICROSURGERYTOOLS IN MICROSURGERY
1. SURGICAL MICROSCOPE:1. SURGICAL MICROSCOPE:
- 4 to 40x magnification- 4 to 40x magnification
- Double-headed system- Double-headed system
- Foot control of focus and zoom- Foot control of focus and zoom
- Interchangeable eyepiece- Interchangeable eyepiece
- Fiber-optic light source- Fiber-optic light source

2. MAGNIFYING LOUPES2. MAGNIFYING LOUPES
*Types:*Types:
a. compound loupesa. compound loupes
b. prismatic loupes (wide-angleb. prismatic loupes (wide-angle
loupes)loupes)
- For hand surgery and dissection of- For hand surgery and dissection of
flaps : 2.5x magnificationflaps : 2.5x magnification
-- For anastomosis : 3.5x or 4.5xFor anastomosis : 3.5x or 4.5x
magnification-- Working distance : 25 tomagnification-- Working distance : 25 to
50 cm50 cm

3. MICROINSTRUMENTS3. MICROINSTRUMENTS
►ScissorsScissors
►Needle holdersNeedle holders
►ForcepsForceps
►ClampsClamps
►Bipolar CoagulatorBipolar Coagulator

PULP TO PULP PINCHPULP TO PULP PINCH

4. MICROSUTURES4. MICROSUTURES
►Most commonly used- Nylon and ProleneMost commonly used- Nylon and Prolene
►Size: 7-0 to 12-0Size: 7-0 to 12-0
►MICRONEEDLES: 3/8 circle taper-pointedMICRONEEDLES: 3/8 circle taper-pointed
needles with a diameter range of 30 to 150needles with a diameter range of 30 to 150
micron are preferredmicron are preferred
►When not in use the needle can be placedWhen not in use the needle can be placed
in the foam in an inclined position ready forin the foam in an inclined position ready for
easy liftingeasy lifting

PREREQUISITES FORPREREQUISITES FOR
MICROSURGEYMICROSURGEY
►COMFORTABLE POSITIONCOMFORTABLE POSITION
►PATIENCEPATIENCE
►GOOD PLANNINGGOOD PLANNING
►ADEQUATE EXPOSUREADEQUATE EXPOSURE

BASIC PRINCIPLES OFBASIC PRINCIPLES OF
MICROSURGERYMICROSURGERY
1. Gentle handling of1. Gentle handling of
tissuestissues
*Avoid grasping the*Avoid grasping the
ends of the vessels toends of the vessels to
be anastomosedbe anastomosed
*Grasp only a small*Grasp only a small
quntity of loosequntity of loose
periadventitiaperiadventitia

2. ADEQUATE DEBRIDEMENT2. ADEQUATE DEBRIDEMENT
► Inspect under highInspect under high
power for signs ofpower for signs of
damagedamage
► Debride until no signsDebride until no signs
of vessel damageof vessel damage
► Strong pulsatile flow ofStrong pulsatile flow of
blood after adequateblood after adequate
debridementdebridement

3.RELIEF OF SPASM3.RELIEF OF SPASM
►Mechanical dilatationMechanical dilatation
►Hydrodistention of the vein graftHydrodistention of the vein graft
►Pharmacologic measuresPharmacologic measures
► Moist gauge soaked in warm salineMoist gauge soaked in warm saline

4. SIMILAR DIAMETER OF4. SIMILAR DIAMETER OF
VESSELSVESSELS
 Vessels with dissimilar diameter uptoVessels with dissimilar diameter upto
50% can be anastomosed50% can be anastomosed
satisfactorilysatisfactorily

►Small vessel isSmall vessel is
dilated and divideddilated and divided
obliquely to giveobliquely to give
adequateadequate
symmetrysymmetry
►When the sizeWhen the size
discrepancy isdiscrepancy is
much greater, anmuch greater, an
interposing veininterposing vein
graft is usedgraft is used

5. TENSION-FREE5. TENSION-FREE
ANASTOMOSISANASTOMOSIS
►Apply an adjustable approximating clamp toApply an adjustable approximating clamp to
bring the vessel end together for convenientbring the vessel end together for convenient
suturingsuturing
►Never apply clamp with excess tensionNever apply clamp with excess tension
►Avoid any kinking or twisting of the vesselsAvoid any kinking or twisting of the vessels
distal to the anastomosisdistal to the anastomosis

6. CORRECT SUTURE6. CORRECT SUTURE
TENSIONTENSION
►Not too tight or too loose suturesNot too tight or too loose sutures
►Too tight sutures- Avoided by a smallToo tight sutures- Avoided by a small
“suture circle” at the end of“suture circle” at the end of
three tiesthree ties

7. APPROPRIATE SUTURE SPACING:7. APPROPRIATE SUTURE SPACING:
-Goal is to achieve an ultimately leak--Goal is to achieve an ultimately leak-
free anastomosis with as few suturesfree anastomosis with as few sutures
as possibleas possible
8. RECHEK OF ANASTOMOSIS:8. RECHEK OF ANASTOMOSIS:
-All anastomosis are rechecked prior to-All anastomosis are rechecked prior to
the final skin closurethe final skin closure

CHOICE OF RECIPIENTCHOICE OF RECIPIENT
VESSELSVESSELS
►Use of healthy vessel of reasonable sizeUse of healthy vessel of reasonable size
with good outflow is the key for successwith good outflow is the key for success
►Pre-operative assessmentPre-operative assessment
 Mobilisation of vsselsMobilisation of vssels

DISSECTION TECHNIQUESDISSECTION TECHNIQUES
►Hemostasis - mustHemostasis - must
*Vascular clips*Vascular clips
*Bipolar coagulator*Bipolar coagulator
*Torniquet*Torniquet
►Avoid perivascular hematomaAvoid perivascular hematoma
►IrrigationIrrigation

PREPARATION OF VESSELSPREPARATION OF VESSELS
►Plane of dissectionPlane of dissection
►Retract the sheath by gentle pullingRetract the sheath by gentle pulling
and remove itand remove it
►Vessels branchesVessels branches
►BackgroundBackground
►Moist fieldMoist field

TECHNIQUE OFTECHNIQUE OF
1.Resection to normal1.Resection to normal
vessels:vessels: --
Resect proximal toResect proximal to
areas withareas with
microscopic signs ofmicroscopic signs of
vessel damage withvessel damage with
fine, straight, sharpfine, straight, sharp
scissors in a singlescissors in a single
motionmotion

Demonstration of forward pulsatile flow priorDemonstration of forward pulsatile flow prior
to clampingto clamping dr sumer yadav (mch plastic and reconstructive

2.Clamping of vessels:2.Clamping of vessels:
- With double- With double
approximating clampapproximating clamp
leaving generousleaving generous
length of vessel endlength of vessel end
for ease of workingfor ease of working
- Tips of the jaws- Tips of the jaws
should project justshould project just
beyond the vessel forbeyond the vessel for
maximal gripmaximal grip

Incorrect vertical positionIncorrect vertical position

Incorrect horizontal positionIncorrect horizontal position

3. Positioning: -Correct position of the clamp is3. Positioning: -Correct position of the clamp is
horizontal and parallel to the operatorhorizontal and parallel to the operator

4. Final Preparation of vessel ends:4. Final Preparation of vessel ends:
► Resect sufficientResect sufficient
periadventitia, flushperiadventitia, flush
with the underlying endwith the underlying end
to expose 2-3 mm ofto expose 2-3 mm of
the vessel wall forthe vessel wall for
suturingsuturing

►If the lumen isIf the lumen is
small or insmall or in
spasm, gentlyspasm, gently
dilate it withdilate it with
vessel dilatorvessel dilator

► Irrigate the lumen withIrrigate the lumen with
solution ofsolution of
heparinizedheparinized salinesaline
(1000 units per 100 ml)(1000 units per 100 ml)

5. SUTURING5. SUTURING
►End to end / End to sideEnd to end / End to side
►Full thickness of wallFull thickness of wall
►Size of the suture materialSize of the suture material
►Number of suturesNumber of sutures
►Distance between suturesDistance between sutures
►Arteries- more sutures than veinsArteries- more sutures than veins

► Pass the needle atPass the needle at
right angles to theright angles to the
wall at a distancewall at a distance
from the marginfrom the margin
slightly greater( 1-2slightly greater( 1-2
times for arteries, 2-3times for arteries, 2-3
times for veins) thantimes for veins) than
the thickness of thethe thickness of the
vessel wallvessel wall

►Make sure that theMake sure that the
posterior wall is notposterior wall is not
accidentally coughtaccidentally cought
►For last 2-3For last 2-3
sutures:sutures:
ModifiedModified
HarshinaHarshina
techniquetechnique

► For thick walledFor thick walled
arteries and largearteries and large
diameter collapsiblediameter collapsible
veins- use 180 degreeveins- use 180 degree
halving method ( firsthalving method ( first
suture at 150 degreesuture at 150 degree
position and secondposition and second
suture at -30 degreesuture at -30 degree

 For thin walledFor thin walled
vessels, use 120vessels, use 120
degree triangulatingdegree triangulating
method for keymethod for key
sutures( First suture atsutures( First suture at
150 degree position150 degree position
and second suture atand second suture at
+30 degree position)+30 degree position)

VENOUS ANASTOMOSISVENOUS ANASTOMOSIS
► Veins are thinner,Veins are thinner,
flatter and moreflatter and more
difficult to anastomosedifficult to anastomose
► Use ringer’s solutionUse ringer’s solution
to float or irrigate theto float or irrigate the
vesselvessel
► Deeper bitesDeeper bites
► More suturesMore sutures

6.RELEASE OF CLAMPS6.RELEASE OF CLAMPS
►The distal clamp is released firstThe distal clamp is released first
►If any major leak, reapply the clamp, irrigateIf any major leak, reapply the clamp, irrigate
and insert additional superficial thicknessand insert additional superficial thickness
suturessutures
►Now release both the clamps- usually smallNow release both the clamps- usually small
amount of blood leaks from anastomosis,amount of blood leaks from anastomosis,
but stops after a few min. with thebut stops after a few min. with the
application of spongesapplication of sponges

ALTERNATIVE ANASTOMOSISALTERNATIVE ANASTOMOSIS
TECHNIQUESTECHNIQUES
1. BACK-WALL FIRST1. BACK-WALL FIRST
( ONE-WAY UP)( ONE-WAY UP)
TECHNIQUETECHNIQUE
-This technique is safest-This technique is safest
because the entirebecause the entire
inside of theinside of the
anastomosis can beanastomosis can be
visualized until thevisualized until the
very last few suturesvery last few sutures
are placedare placed

2. FLIPPING TECHNIQUE2. FLIPPING TECHNIQUE
When free flap, digit or vein graft is fixed fo mobile vessel, itWhen free flap, digit or vein graft is fixed fo mobile vessel, it
can be flipped to expose the back-wall for repair, ascan be flipped to expose the back-wall for repair, as
rotation is not possiblerotation is not possibledr sumer yadav (mch plastic and reconstructive

3. CONTINUOUS SUTURING3. CONTINUOUS SUTURING
► Acceptable patency rates ( 92% for arteries, 84%Acceptable patency rates ( 92% for arteries, 84%
for veins) comparable with interrupted suturesfor veins) comparable with interrupted sutures
► Advantages: Quicker and more hemostaticAdvantages: Quicker and more hemostatic
► Disadvantages:Disadvantages:
* Potential for creating purse-string constriction at* Potential for creating purse-string constriction at
the site of anastomosisthe site of anastomosis **
Entrapment of the suture material in the clampEntrapment of the suture material in the clamp
* Breakage* Breakage
of the sutureof the suture
► So less favourableSo less favourable

4. SLEEVE ANASTOMOSIS4. SLEEVE ANASTOMOSIS
► Microanastomosis ofMicroanastomosis of
vessels in 1 mmvessels in 1 mm
external diameterexternal diameter
range can berange can be
accomplished byaccomplished by
means of invaginatingmeans of invaginating
technique with fewertechnique with fewer
sutures than the end tosutures than the end to
end method of closureend method of closure

►Advantages:Advantages:
- Quicker- Quicker
- Less intraluminal suture exposure- Less intraluminal suture exposure
- Less vessel trauma owing to fewer- Less vessel trauma owing to fewer
suturessutures
►Disadvantages:Disadvantages:
- Patency rate is significantly less than- Patency rate is significantly less than
that achieved by the conventional end tothat achieved by the conventional end to
end method, so it is not superior in clinicalend method, so it is not superior in clinical
situationssituations

END TO SIDE ANASTOMOSISEND TO SIDE ANASTOMOSIS
►Indications:Indications:
*To preserve patency of the recipient vessel*To preserve patency of the recipient vessel
in lower limb,esp. in elderly patients, wherein lower limb,esp. in elderly patients, where
sacrifice of a major vessel can have asacrifice of a major vessel can have a
serious effect on the distal blood flowserious effect on the distal blood flow
*Considerable size or wall thickness*Considerable size or wall thickness
mismatch between the vesselsmismatch between the vessels

Steps of end to side anastomosisSteps of end to side anastomosisdr sumer yadav (mch plastic and reconstructive

An optional end to side anastomosisAn optional end to side anastomosisdr sumer yadav (mch plastic and reconstructive

►Advantages:Advantages:
- Search for recipient arteries is- Search for recipient arteries is
simplifiedsimplified
- No. of possible sites to which free- No. of possible sites to which free
flaps can be transferred is greatlyflaps can be transferred is greatly
increasedincreased

PATENCYPATENCY
►Return of colourReturn of colour
►Capillary oozing and venous bleeding fromCapillary oozing and venous bleeding from
the revascularized tissuethe revascularized tissue
►Direct inspection under the microscopeDirect inspection under the microscope
►Uplift testUplift test

PATENCY TESTPATENCY TEST
► This is traumatic and isThis is traumatic and is
performed as gentlyperformed as gently
and infrequently asand infrequently as
possiblepossible

ANASTOMOTIC FAILUREANASTOMOTIC FAILURE
A) TECHNICAL ERRORS:A) TECHNICAL ERRORS:
1.1. TearingTearing
2.2. LeakingLeaking
3.3. NarrowingNarrowing
4.4. Through-stitchingThrough-stitching
5.5. Inclusion of adventitiaInclusion of adventitia
B) Poor flow from proximal vessel due toB) Poor flow from proximal vessel due to
undetected damage more proximally orundetected damage more proximally or
vasospasmvasospasm

C) A clot or thrombus at the anastomotic site or inC) A clot or thrombus at the anastomotic site or in
an area where a clamp was appliedan area where a clamp was applied
- Damage to endothelium fromDamage to endothelium from
+ Excessive clamp pressure+ Excessive clamp pressure
+ Poor technique or+ Poor technique or
+ Contamination+ Contamination
- Prevention:Prevention:
+ Flushing of the suture line with heparinized+ Flushing of the suture line with heparinized
solutionsolution ++
Systemic heparin (40 u/kg before completion ofSystemic heparin (40 u/kg before completion of
anastomosis and release of clamps)anastomosis and release of clamps)

REVISION OF THE FAILEDREVISION OF THE FAILED
►If the patency test reveals slow filling ofIf the patency test reveals slow filling of
the distal vessel, revise thethe distal vessel, revise the
anastomosis, carefully keeping originalanastomosis, carefully keeping original
problem in mindproblem in mind
►Insert a vein graft, if the vessel lengthInsert a vein graft, if the vessel length
is insufficientis insufficient

*Poor proximal flow that does not*Poor proximal flow that does not
respond to local vasodilator andrespond to local vasodilator and
warming may require:warming may require:
- Proximal exploration of the vesselProximal exploration of the vessel
- Dilatation along a proximal length ofDilatation along a proximal length of
vessel sufficient to relievevessel sufficient to relieve
vasospasmvasospasm

FACTORS INFLUENCING FAILUREFACTORS INFLUENCING FAILURE
OF ANASTOMOSISOF ANASTOMOSIS
A. TECHNICAL:A. TECHNICAL:
► Both walls sutured togetherBoth walls sutured together
► Traumatic vessel handlingTraumatic vessel handling
► Apposition of vessel edgesApposition of vessel edges
► Disproportional vessel sizeDisproportional vessel size
► Tension at suture lineTension at suture line
► Excessive clamp pressureExcessive clamp pressure
► Kinking of vesselsKinking of vessels

B. REPERFUSION FAILURE:B. REPERFUSION FAILURE:
►Blood turbulenceBlood turbulence
►SpasmSpasm
►HypercoagulabilityHypercoagulability
►AcidosisAcidosis
►ColdCold
►HypovolemiaHypovolemia
►VasoconstrictorsVasoconstrictors

C. POSTOPERATIVE CARE:C. POSTOPERATIVE CARE:
►InfectionInfection
►AcidosisAcidosis
►ColdCold
►Limb positionLimb position
►Environmental factorsEnvironmental factors

POST-OPERATIVE MEASURESPOST-OPERATIVE MEASURES
►Oxygen administationOxygen administation
►Bed rest or limited movements for 3 to 5Bed rest or limited movements for 3 to 5
daysdays
►Warm roomWarm room
►Limb elevation to decrease the venousLimb elevation to decrease the venous
congestioncongestion
►Fluid administrationFluid administration

►Adequate analgesiaAdequate analgesia
►Limitation of visitors and telephone calls toLimitation of visitors and telephone calls to
decrease the emotional stressdecrease the emotional stress
►Prohibition of smoking, caffeine andProhibition of smoking, caffeine and
chocolate because they may causechocolate because they may cause
vasoconstrictionvasoconstriction

principles of microvascular surgery

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