IlizarovIlizarov

Dr.Abhishek Dr.Abhishek chachan Mahatma chachan Mahatma gandhi hospital gandhi hospital sitapura, jaipur sitapura, jaipur

Rajasthan, INDIARajasthan, INDIA

Historical reviewHistorical review

Gavriil Gavriil Abramovich Abramovich IlizarovIlizarov

( 15 june 1921 – 24 ( 15 june 1921 – 24 july 1992) july 1992)

Russian physician, Russian physician, known for known for inventing the inventing the Ilizarov apparatusIlizarov apparatus

Historical reviewHistorical review

Ilizarov was born in the AzerbaijanIlizarov was born in the Azerbaijan

In 1944 he was sent to a rural In 1944 he was sent to a rural hospital in hospital in Kurgan Oblast in in Siberia

In 1951, he developed a In 1951, he developed a revolutionary technique and called revolutionary technique and called it a RING FIXATOR . it a RING FIXATOR .

Priciples of IllizarovPriciples of Illizarov DISTRACTION OSTEOGENESIS. This refers to DISTRACTION OSTEOGENESIS. This refers to

the induction of new bone between bone the induction of new bone between bone surfaces that are pulled apart in a gradual, surfaces that are pulled apart in a gradual, controlled manner.controlled manner.

The distraction initially gives rise to The distraction initially gives rise to NEOVASCULARISATION which is what NEOVASCULARISATION which is what actually stimulates new bone formation. actually stimulates new bone formation.

In addition, there is simultaneous histogenesis In addition, there is simultaneous histogenesis of muscles, nerves and skin; in bone diseases of muscles, nerves and skin; in bone diseases (osteomyelitis , fibrous dysplasia, pseudo-(osteomyelitis , fibrous dysplasia, pseudo-arthrosis) this new bone replaces pathological arthrosis) this new bone replaces pathological bone with normal bone. bone with normal bone.

Indications of IllizarovIndications of Illizarov In treating of bone infectionsIn treating of bone infections In Poliomyelitis Sequelae (in limb lengthening and In Poliomyelitis Sequelae (in limb lengthening and

correction of deformities)correction of deformities) In treating of malunited fractures and non-unionsIn treating of malunited fractures and non-unions To correct deformities of the limbs, both To correct deformities of the limbs, both

congenital and acquiredcongenital and acquired In treating badly comminuted fractures (multiple In treating badly comminuted fractures (multiple

fragments) in the limbsfragments) in the limbs Lengthening of limb stumps, foot stumps and Lengthening of limb stumps, foot stumps and

fingersfingers To increase height (for dwarfs)To increase height (for dwarfs)

Instruments and their Instruments and their useuse

Primary components – That join Primary components – That join skeleton to finished frameskeleton to finished frame

Transosseous wiresTransosseous wires RingsRings Wire fixaion boltsWire fixaion bolts

Instruments and usesInstruments and uses

Secondary components – Used to Secondary components – Used to construct frameconstruct frame Threaded and telescopic rodsThreaded and telescopic rods Connecting plates Connecting plates Hinges and postsHinges and posts Nuts and boltsNuts and bolts

Instruments used in Instruments used in ilizarov ilizarov

Wire fixation boltWire fixation bolt

CannulatedCannulated Cannulated Cannulated

with threaded with threaded headhead

SlottedSlotted

Wire fixation buckleWire fixation buckle

Allows Allows mechanical mechanical derotation or derotation or angular angular correctionscorrections

Telescopic rodTelescopic rod

Provide stability Provide stability when long when long distance must distance must be spanned be spanned between ringsbetween rings

Allows Allows lengtheninglengthening

Hinge ( Male and female)Hinge ( Male and female)

Threaded socketThreaded socket

Inerconnect Inerconnect threaded rodsthreaded rods

Stabilize two Stabilize two rings togetherrings together

WiresWires

Trocar- Cancellous Trocar- Cancellous bonebone

Bayonet – Cortical Bayonet – Cortical bonebone

Olive wiresOlive wires

Dynamometric wire Dynamometric wire tensionertensioner

Biomechanics Biomechanics

Tensioned wires (1.5 and 1.8) Tensioned wires (1.5 and 1.8) achieve rigidity equal to half pins.achieve rigidity equal to half pins.

And retain elasticity and low axial And retain elasticity and low axial stiffness.stiffness.

Should not exceed 50% of yield Should not exceed 50% of yield strength of wirestrength of wire

Maximum limitsMaximum limits 90 kg for 1.5 mm wire90 kg for 1.5 mm wire 130 kg for 1.8 mm wire130 kg for 1.8 mm wire

BiomechanicsBiomechanics

Tension in soft tissues also Tension in soft tissues also determine the tension to be applied determine the tension to be applied to wireto wire

In Lengthening its safer to tension In Lengthening its safer to tension wires to 80 -90 Kg wires to 80 -90 Kg

Increasing wire tension from 90-130 Increasing wire tension from 90-130 increases bending and axial stiffness increases bending and axial stiffness but lowers torsional stiffnessbut lowers torsional stiffness

Biomechanics Biomechanics Number of wiresNumber of wires

More the number/ring more More the number/ring more stable is the fixatorstable is the fixator

Wire spreadWire spread 90/90 ideal- Anatomical 90/90 ideal- Anatomical

constraintsconstraints 45/135 configuration less 45/135 configuration less

stable in flexionstable in flexion Off centeringOff centering

Higher axial stiffness and Higher axial stiffness and lower torsional stiffness.lower torsional stiffness.

Olive wiresOlive wires increase bending, axial and increase bending, axial and

torsional stiffnesstorsional stiffness

BiomechanicsBiomechanics

Wires are self stiffeningWires are self stiffening Wires derive increasing rigidity with Wires derive increasing rigidity with

increasing deflectionincreasing deflection On releasing deflection load, wires On releasing deflection load, wires

spring back to its original axially spring back to its original axially tensioned positiontensioned position

Allows axial micromotionAllows axial micromotion

BiomechanicsBiomechanics

Wire diameterWire diameter Increase diameter increases tension Increase diameter increases tension

Optimum wireOptimum wire 1.5 mm for children1.5 mm for children 1.8 mm for adults1.8 mm for adults

Biomechanics of RingBiomechanics of Ring

Stability of assemblyStability of assembly NumberNumber SizeSize Position of ringsPosition of rings

Closer the middle two rings to the Closer the middle two rings to the fracture more stable is the fracture more stable is the configurationconfiguration

BiomechanicsBiomechanics

Reduction of 2 cm of radius of ringsReduction of 2 cm of radius of rings 77% rise in axial stiffness under 100 N 77% rise in axial stiffness under 100 N

loadload Only torsional stiffness increased Only torsional stiffness increased

with increasing ring diameterwith increasing ring diameter Ilizarov recommends minimum of 2 Ilizarov recommends minimum of 2

cm between skin and ring to cm between skin and ring to accomadate edema as blood flow accomadate edema as blood flow increases increases

Biomechanics of Biomechanics of FulcrumFulcrum

In deformity correction Olive wires In deformity correction Olive wires are used as fulcrum to prevent are used as fulcrum to prevent slippage of wiresslippage of wires

Biomechanics of hinges Biomechanics of hinges

Biomechanics of HingesBiomechanics of Hinges

Central Central hinge causes hinge causes distraction distraction on concave on concave side and side and compression compression on convex on convex side.side.

Biomechanics HingesBiomechanics Hinges

Fulcrum on the Fulcrum on the convex sideconvex side

Hinge at apex of Hinge at apex of deformity – deformity – distraction on distraction on convex sideconvex side

Hinge placed Hinge placed more laterally more laterally results in results in lengthening lengthening along with along with angular angular correctioncorrection

Factors affecting stability Factors affecting stability of fixatorof fixator

I Apparatus related (Extrinsic) factors I Apparatus related (Extrinsic) factors Spread between crossing wires approaching Spread between crossing wires approaching

90/9090/90 Increase in wire diameter and tensionIncrease in wire diameter and tension Increase in number of ringsIncrease in number of rings Decreased ring size (wire span distance of Decreased ring size (wire span distance of

2-3cm around the limb)2-3cm around the limb) Close positioning of center rings to fracture Close positioning of center rings to fracture

or nonunion site.or nonunion site. Use of olive (stop) wires.Use of olive (stop) wires.

Factors affecting stability Factors affecting stability of fixatorof fixator

II. Intrinsic factors-II. Intrinsic factors- Area of tissue contact between the bone Area of tissue contact between the bone

ends.ends. Modulus of elasticity of tissue between Modulus of elasticity of tissue between

bone endsbone ends Length of gap between bone ends.Length of gap between bone ends. Tension of soft tissue surrounding boneTension of soft tissue surrounding bone Mechanical configuration and interlock Mechanical configuration and interlock

between bone endsbetween bone ends

Histology of distraction Histology of distraction osteogenesisosteogenesis

FIZ – Fibrous FIZ – Fibrous interzoneinterzone

PMF- Primary PMF- Primary mineralization frontmineralization front

MCF – microcolumn MCF – microcolumn formationformation

HBS – Host bone HBS – Host bone surfacesurface

HistologyHistology Latency period – similar to fracture healingLatency period – similar to fracture healing 1 week after distraction- 1 week after distraction-

Fibrous interzone fills corticotomy gap (6-7 Fibrous interzone fills corticotomy gap (6-7 mm)mm)

By 2By 2ndnd week- week- Osteoblasts appear on each side of FIZ and Osteoblasts appear on each side of FIZ and

collagen bundles fuse with osteoid like matrixcollagen bundles fuse with osteoid like matrix Later in 2Later in 2ndnd week Osteoid mineralizes (Primary week Osteoid mineralizes (Primary

Mineralization Front)Mineralization Front) New bone forms at two cut surfaces of New bone forms at two cut surfaces of

corticotomy.corticotomy.

3 weeks of distraction3 weeks of distraction New bone differentiates to microcolumn New bone differentiates to microcolumn

formation {MCF} with maximum diameter formation {MCF} with maximum diameter of 200 microns.of 200 microns.

FIZ persists throughout distractionFIZ persists throughout distraction After distraction FIZ ossifies, MCF After distraction FIZ ossifies, MCF

unifies bridging the gapunifies bridging the gap At the conclusion of distraction, the FIZ At the conclusion of distraction, the FIZ

ossifies, creating one zone of MCF and ossifies, creating one zone of MCF and completely bridging the gap During this completely bridging the gap During this 6-week consolidation period6-week consolidation period

During the 6 weeks after frame During the 6 weeks after frame removal, the osteogenic area removal, the osteogenic area remodels into cortex and medullary remodels into cortex and medullary canal canal

Blood flow peaks 7 times normal Blood flow peaks 7 times normal during first 4 weeks of distractionduring first 4 weeks of distraction

Then Decreases but remains Then Decreases but remains elevated 3 times normal for next 3 elevated 3 times normal for next 3 monthsmonths

Factors affecting Factors affecting osteogensisosteogensis

Stability of bone fragmentsStability of bone fragments local or regional blood supplylocal or regional blood supply Latency period Latency period Rate and rhythm of distraction Rate and rhythm of distraction Function of limbFunction of limb Timing of frame removalTiming of frame removal

Anatomic considerationsAnatomic considerations

FEMURFEMUR- - When inserting wires into the When inserting wires into the femur, there are several basic problemsfemur, there are several basic problems

First, the bulk of the soft tissues causes First, the bulk of the soft tissues causes difficulties, especially posteriorly, in the difficulties, especially posteriorly, in the buttock.buttock.

Second, the neurovascular Second, the neurovascular bundles,especially the superficial femoral bundles,especially the superficial femoral artery,can be damaged during wire artery,can be damaged during wire insertion. insertion.

Third, the sciatic nerve prevents direct AP Third, the sciatic nerve prevents direct AP wire insertion. wire insertion.

Insert the first olive wire from anteromedial to posterolateral two fingerbreadths lateral to Insert the first olive wire from anteromedial to posterolateral two fingerbreadths lateral to the femoral artery. Insert a second olive wire from back to front, 15° medial to the first the femoral artery. Insert a second olive wire from back to front, 15° medial to the first wire. The posterior olive on this wire prevents the entire frame from displacing anteriorly wire. The posterior olive on this wire prevents the entire frame from displacing anteriorly while the patient lies in bed. A third wire is often inserted between the first two.while the patient lies in bed. A third wire is often inserted between the first two.

To stabilize a hip during femoral lengthening.especially a hip that might sublux or To stabilize a hip during femoral lengthening.especially a hip that might sublux or dislocate,it may be necessary to insert wires into the supraacetabular or iliac portion of the dislocate,it may be necessary to insert wires into the supraacetabular or iliac portion of the pelvis. Leave these wires in place (not allowing movement) until lengthening is complete. pelvis. Leave these wires in place (not allowing movement) until lengthening is complete. Thereafter, the wires are removed and hip motion is commenced.Thereafter, the wires are removed and hip motion is commenced.

For the distal femur, insert wires into either the transverse or the coronal plane. For the distal femur, insert wires into either the transverse or the coronal plane. When selecting the transverse plane, cross the wires at an angle of no less than When selecting the transverse plane, cross the wires at an angle of no less than 60°. Likewise, insert olives from both directions for enhanced stability60°. Likewise, insert olives from both directions for enhanced stability

TIBIATIBIAThe proximal ring for a tibial mounting usually The proximal ring for a tibial mounting usually

incorporates a wire that passes through the incorporates a wire that passes through the fibular head and into the tibia to prevent fibular head and into the tibia to prevent subluxation of the proximal tibia fibula joint subluxation of the proximal tibia fibula joint during lengthening or deformity correction. A during lengthening or deformity correction. A second wire through the tibia crosses the second wire through the tibia crosses the fibula wire, paralleling the medial face of the fibula wire, paralleling the medial face of the tibia. A third transverse drop wire is inserted tibia. A third transverse drop wire is inserted across the tibia into the location used for across the tibia into the location used for skeletal traction. Additional wires are inserted skeletal traction. Additional wires are inserted as needed for greater stability. Distally, the as needed for greater stability. Distally, the fibula must usually be incorporated into the fibula must usually be incorporated into the configuration with a distal fibulotibial wire.configuration with a distal fibulotibial wire.

.

HUMERUSHUMERUS The Proximal And Distal Ends Of The Bone Can Be The Proximal And Distal Ends Of The Bone Can Be

Secured With Three Wires EachSecured With Three Wires Each Through The Proximal Humerus, Abduct The Arm 90° and Through The Proximal Humerus, Abduct The Arm 90° and

externally rotate it 20°. Drive olive wires from both the externally rotate it 20°. Drive olive wires from both the anterior and posterior directions. The third wire is a drop anterior and posterior directions. The third wire is a drop

wire off the plane of the ringwire off the plane of the ring.. In the distal humerus, insert olive wires crossing in the In the distal humerus, insert olive wires crossing in the

frontal plane, one from the lateral supracondylar ridge and frontal plane, one from the lateral supracondylar ridge and one from the medial supracondylar ridge A drop wire one from the medial supracondylar ridge A drop wire (perpendicular to the bone's axis) completes the (perpendicular to the bone's axis) completes the configurationconfiguration

Insert the wires into both epicondyles, exiting the humerus Insert the wires into both epicondyles, exiting the humerus proximally at the medial and lateral supracondylar ridges. proximally at the medial and lateral supracondylar ridges. Take care not to transfix either the ulnar or radial nerves. Take care not to transfix either the ulnar or radial nerves. A third wire straight across from one supracondylar ridge A third wire straight across from one supracondylar ridge to the other completes the mounting.to the other completes the mounting.

After all wires are in place, flex and extend the elbow: After all wires are in place, flex and extend the elbow: there should be no block in either direction.there should be no block in either direction.

FOOTFOOT Before Inserting Wires Into The Before Inserting Wires Into The

Calcaneus, Consider The Diameter Calcaneus, Consider The Diameter Of The Wires,Number , The Angles Of The Wires,Number , The Angles Between, The Direction Of Insertion, Between, The Direction Of Insertion, The Plane Of The Wires.The Plane Of The Wires.

diameter of the wires is determined diameter of the wires is determined by the ageby the age

the amount of osteoporosis and the amount of osteoporosis and degree of deformity influence the degree of deformity influence the number of wires selected-more then number of wires selected-more then 2 wire2 wire

Next, consider the direction from which the Next, consider the direction from which the wires are to be inserted. When correcting an wires are to be inserted. When correcting an equinus, insert both olive wires from the equinus, insert both olive wires from the posterior part of the heel toward the forefoot. posterior part of the heel toward the forefoot. When correcting a cavus or calcaneus When correcting a cavus or calcaneus deformity, insert the olive wires from the deformity, insert the olive wires from the forepart of the foot toward the heel. When forepart of the foot toward the heel. When correcting a forefoot adduction deformity, keep correcting a forefoot adduction deformity, keep both olive wires on the medial side of the heel. both olive wires on the medial side of the heel. When a valgus of the heel is being corrected, When a valgus of the heel is being corrected, place the olive on the lateral side of the foot. In place the olive on the lateral side of the foot. In combined deformities such as talipes combined deformities such as talipes equinovarus, the position of the olives is equinovarus, the position of the olives is determined by the nature of the pathologydetermined by the nature of the pathology

PrecautionsPrecautions

Corticotomy complete – Confirm Corticotomy complete – Confirm fluoroscopicallyfluoroscopically

Distraction no more than 2-4 mmDistraction no more than 2-4 mm Angulation no more than 20-30 Angulation no more than 20-30

degreesdegrees

Radiographic classification Radiographic classification of regenerateof regenerate

NormotrophicNormotrophic

Hypertrophic and Hypertrophic and

HypotrophicHypotrophic

NormotrophicNormotrophic Early radiodense bone formation b/w 21 to 28 Early radiodense bone formation b/w 21 to 28

daysdays At this point bone ends have distracted approx At this point bone ends have distracted approx

14 mm apart14 mm apart Definite columns of longitudinally oriented new Definite columns of longitudinally oriented new

bone extends from each corticotomy surface bone extends from each corticotomy surface towards central transverse radiolucent area towards central transverse radiolucent area measuring approximately 4 mmmeasuring approximately 4 mm

As distraction proceeds columns of new bone As distraction proceeds columns of new bone elongate maintaining central radiolucent bandelongate maintaining central radiolucent band

Following distraction new bone bridges Following distraction new bone bridges centrally & proceeds to homogenous centrally & proceeds to homogenous appearanceappearance

Radiologic evaluation of Radiologic evaluation of calluscallus

HypertrophicHypertrophic

Regenerate appears Regenerate appears radiologically before radiologically before 20 days20 days

Cross sectional Cross sectional diameter of diameter of regenerate exceeds regenerate exceeds that of corticotomy that of corticotomy surfacesurface

Rate of distraction Rate of distraction must be increasedmust be increased

HypertrophicHypertrophic

FactorsFactors Young patientYoung patient More active patientsMore active patients Good local blood supply ( Humerus)Good local blood supply ( Humerus)

HypotrophicHypotrophic

Radioloigcal new bone appears after 30 Radioloigcal new bone appears after 30 daysdays

Or if bone column has multiple breaksOr if bone column has multiple breaks Or regenerate has hourglass appearanceOr regenerate has hourglass appearance FactorsFactors

Vascular deficitsVascular deficits Local scarring or swelling which constricts Local scarring or swelling which constricts

new tissue formationnew tissue formation Lack of function or weight bearing by the Lack of function or weight bearing by the

patientpatient

HypotrophicHypotrophic

Type AType A Spotty Spotty

radiodensities radiodensities after day 50 after day 50 indicating poor indicating poor vascularityvascularity

HypotrophicHypotrophic

Type BType B Hourglass Hourglass

configuration – configuration – distraction rate distraction rate too fasttoo fast

HypotrophicHypotrophic

Type CType C Irregular bone Irregular bone

columns indicate columns indicate instability or instability or vascular vascular disruptiondisruption

HypotrophicHypotrophic

Type DType D Focal failure of Focal failure of

bone formation bone formation indicate local indicate local vascular injury or vascular injury or periosteal damage periosteal damage if peripheralif peripheral

Timing of Frame Timing of Frame RemovalRemoval Depends on the condition of the limb and pathology Depends on the condition of the limb and pathology

invovledinvovled X Ray: Ideally the regenrate bone should be X Ray: Ideally the regenrate bone should be

remodelled with cortex and medullary canal of equal remodelled with cortex and medullary canal of equal cross section diameter to the host bonecross section diameter to the host bone

Q.C.T: Quantitave C.T. scanning of central osteogenic Q.C.T: Quantitave C.T. scanning of central osteogenic area density must be 60% of opposite normal bone is area density must be 60% of opposite normal bone is satisfactory for removal of framesatisfactory for removal of frame

Clinical test for frame dynamization: prior to removal Clinical test for frame dynamization: prior to removal the wire tension is gradually reduced to minimum and the wire tension is gradually reduced to minimum and patient allowed for full wt bearing,if new bone patient allowed for full wt bearing,if new bone supoorts full load without pain or deformity,then supoorts full load without pain or deformity,then device can be safely removeddevice can be safely removed

Clinical applicationsClinical applications

Non unions and deformity correctionNon unions and deformity correction Bone transportBone transport FracturesFractures Limb lengtheningLimb lengthening

Non unionNon union

Hypertrophic non-unions have a vital blood supply from each bone end and a dense collagenous interface.

Bone formation can be stimulated by primary distraction

Atrophic non-unions, with thin, non-reactive bone ends, are treated initially with compression and then with distraction

Bone transportBone transport

Intercalary defects resulting from trauma, infection, tumor, or prosthetic replacement can be treated

with transport of a segment of bone within the limb

Limb lengtheningLimb lengthening

The Ilizarov method allows the surgeon to perform complex and extended lengthening of both congenital and acquired short limbs

Rate and quality of bone formation can be influenced by certain factors Amount of lengthening that is attempted, the site of the lengthening, the selection of the bone to be lengthened, and the number of sites of lengthening within

the bone

The rate of healing is directly proportional to the length of the distraction gap —

the greater the lengthening, the longer the time needed for treatment

Metaphyseal sites generally heal faster than diaphyseal sites.

The femur has been shown to heal faster than the tibia

And tibiae lengthened at two sites heal faster than those lengthened at only one site

Older patients tend to heal more slowly, with greater delays occurring after the age of twenty years

ComplicationsComplications

Complications can involve the pin tracks bones Joints neurovascular structures Mental status

Inflammation surrounding pin tracks is common as a result of mechanical or thermal damage Cellulitis abscess or local osteomyelitis.

Osseous complications may involve premature or delayed consolidation non-union axial deviation late bending fracture

During the lengthening, motion of the joint may be temporarily or permanently lost as a result of muscle contracture arthrofibrosis, or damage to the cartilage.

Nerves and vessels may be damaged directly by pins or osteotomes or Indirectly by the actual stretching.

Regional edema is common; Painful neurapraxia is less common;

and Reflex sympathetic dystrophy, and

compartment syndrome are rare

Advantages of Ilizarov Advantages of Ilizarov over Cantilever type Ex over Cantilever type Ex

fixfix Elastic allow axial micromotion, and Elastic allow axial micromotion, and

controls shear stresscontrols shear stress Multilevel multiplanar fixator, distribute Multilevel multiplanar fixator, distribute

stresses more evenly across fracture - 3 stresses more evenly across fracture - 3 dimensional correction is possible dimensional correction is possible intraop and post op.intraop and post op.

Stable- allow immediate weight bearing Stable- allow immediate weight bearing Better in osteoporotic boneBetter in osteoporotic bone Pins are thin and does not cause much Pins are thin and does not cause much

damage to tissuesdamage to tissues