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External skeletal fixators

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  • GPC Medical (US FDA 510 (k) approved) is a star exporter house certified by government of India. We are a reputed indian exporter & manufacturer company of india. We are worldwide exporter of orthopaedic external fixators from India. Know more about our external fixator devices: http://bit.ly/UM2u6C
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External skeletal fixators External skeletal fixators Presentation Transcript

    • External skeletal fixation techniques
    • Shahnawaz ahmad bhat
    • 4857
  • Definition
    • A method of fracture treatment ,that involves the percutaneous placement of a series of transcortical pins or wires , which are externally connected to a rigid frame
  • Indications for use
    • Long bone fractures
    • Open fractures
    • Comminuted fractures that cannot be anatomically reconstructed
    • Osteomyelitis
    • High-energy fractures with soft- tissue injuries and vascular compromise
  • Cont’d........
    • Transarticular ESF in arthrodesis
    • Temporary splintage during healing of soft tissue or osseous structures
    • Nonunion / with bone graft
    • Corrective osteotomy for antebrachial /tibial growth deformities
    • Limb lengthening procedures
  • Cont’d……
    • Conjunction with internal fixation- in humeral, femoral or tibial fractures
    • Hybrid ESF system- humeral, radial or tibial fractures with very short distal or proximal fragment
  • Cont’d…..
    • Mandibular or maxillary fractures- usually with acrylic fixators
    • Lubosacral fractures & luxations
    • Avian limb fractures
    • Fracture repair in small exotic mammals
  • Advantages of ESF
    • Minimally invasive method, preserving blood supply & soft tissues
    • No implants at the fracture site
    • Possible closed application which limits iatrogenic trauma
    • Provides immediate wt. bearing after surgery
    • Maintains normal joint mobility
    • Provides optimum environment for osteosynthesis & wound healing
    • compatibility with internal fixation devices
    • Technical ease of application and removal
    • wound management in open fractures
    • Reusability of the pin clamps & connecting bars
  • Disadvantages of ESF
    • Device must be cleaned and monitored regularly
    • Care to prevent additional damage to animal/device
    • Aftercare is more labor intensive
    • More rigid type II and III frames cannot be used for fractures of femur & humerus
    • Difficult to apply and more pain in areas of increased muscle mass
    • Extremely high cost
  • ESF FRAMES LINEAR CIRCULAR HYBRID
  • Equipment ESF 3 BASIC UNITS FIXATION PINS EXTERNAL CONNECTORS LINKAGE DEVICES Inserted into bone To hold major Fragments Support fractured Bones Attach fixation Pins & external Connectors
  • FIXATION PINS : classification
    • on basis of implantation method
    HALF PIN penetrate only one skin surface but both bone cortices FULL PIN Panetrate one skin surface then both cortices ,and then the opposite Skin Surface
  • On basis of structural design
    • Smooth pin :
    • Rely on friction to remain stable in the bone
    • Threaded pins :
    • Positive profile and negative profile
    • Centrally threaded and end threaded
  • Positive & negative profile threaded pins
    • Pins in which core diameter of the threaded section is smaller than the diameter of the smooth section have negative thread profile
    • If the core diameter is consistent b/w smooth & threaded regions ,thread profile is positive
  • Positive profile transfixation pins used in ESF
  • Centrally threaded & End threaded pins
    • Centrally threaded pins are used as full pins with type ÌÌ or ÌÌÌ external fixator frames
    • Central threads engage bone & smooth pin ends extend beyond the skin surface
    • End threaded pins are described a/c to no. of cortices engaged by threads (one cortex & two cortex end threaded pins)
    End treaded pin Centrally threaded pin
  • External connectors
    • Made up of stainless steel, titanium alloy , carbon fiber,aluminium or acrylic
    • External fixator & linkage devices may be fashioned from acrylic for ACRYLIC -PIN EXTERNAL FIXATOR (APEF)
    • APEF system contains +ve profile threaded fixation pins ,packaged acrylic & sterilized acrylic column molding tubes
  • SK double clamp Secur-U clamp S K single clamp Kirschner double clamp Kirschner single clamp Kirschner type linkage devices for joining fixation Pins to external connecting bars & external connecting bars to each other.Note the larger holes for the external connecting bars & smaller holes in the bolts for Fixation pins Linkage devices
  • Linear ESF Configurations
    • Type Ì ,ÌÌ or ÌÌÌ configuration
    • TYPE Ì Configuration
    • Utilize half pin splintage fixation pins
    • Connecting frame placed on only one side of the limb
    • Unilateral constructs
    • Classified as * type Іa (unilateral and uniplanar)
    • * type Іb (unilateral and biplanar)
  • Type Ǐ a (unilateral –uniplanar ) fixators
    • All the fixation pins & connecting frame occupy a single plane (uniplanar)
    • Usually applied to cranial medial surface of radius/ tibia and lateral surface of femur/ humerus
    • Fixation pins are half pins
  • Type Ǐb (unilateral -biplanar ) fixators
    • Applied most often to radius & tibia
    • For radius & tibia–one ext. bar is placed on craniomedial surface & 2 nd bar on craniolateral surface
  • Type ǏǏ (bilateral-uniplanar ) fixators
    • Utilize full pin splintage fixation pins
    • Cannot be placed on femur/ humerus because of adjacent body wall
    • Applied only to radius/tibia in mediolateral plane
    • Maximal type ІІa & minimal type ІІb
    Maximal type ІІa Minimal type ІІb
  • Type ǏǏǏ(Bilateral-biplanar)fixator
    • Combination of type І and type ІІ
    • Type І and type ІІ systems placed approx. 90 ° to each other
    • Can’t be applied to femur or humerus
    • Indicated in very large dogs
  • TIE-IN CONFIGURATION
    • Combination of ESF (type Іa or Іb) with intramedullary pin
    • Increases rigidity of fracture fixation in humerus & femur as type ІІ &Type ІІІ frames cannot be applied
    • No. of fixation pins is limited to 2 or 3 pins above & below the fracture
  • Tie –in configuration
  • Biomechanics
    • Fixator rigidity depends on:
    • Type of configuration-
    • Type ІІІ > type ІІ > type І
    • biplanar type Іb more resistant to cranial/caudal shear forces compared with type ІІ.
    • Number of used pins: at least 2 & up to 4 pins/bone segment
    • Diameter and design of the pins – the diameter ≤ 25 % of the bone’s diameter
    • The fixator rigidity by widening pin spacing within pin groups & by the distance between pin groups
    • The most central pin should be 1-2 cm away from the fracture line
  • Cont’d…..
    • Moving the connecting bar closer to the bone makes the pins more resistant to bending
    • Using a “tie-in” configuration increase significant in bending strength
  • Fixation pin application
    • Preoperative planning
    • Patient fracture assessment
    • Most important principle -asceptic surgery
    • Injured limb suspended from hook in the ceiling
    • Patient Draping
    • choose a surgical approach
    • Delimitation of safe corridors
    • for insertion of pins
  • Cont’d……..
    • Most proximal and distal pins inserted after a stab skin incision
    • Predrilling a pilot hole with slightly smaller diameter drill bit
    • Transfixating pins inserted by using low-speed power drill
    • Fracture reduced & connecting bar connected to proximal and distal pins by clamps
    • Clamps placed 1-2 cm away from the skin surface
    • Central pins are inserted above and below the fracture
    • Rest of needed pins inserted & bolts tightened
  • Postoperative management
    • Postoperative analgesia
    • Pin-skin interface cleaned with antiseptic solution
    • Incision around pins released/extended in case of skin tension
    • Sterile gauze sponges placed around & b/w fixation pins
    • Limb wrapped with vetrap (bandage material )
    • Activity restricted to least walking & physical rehabilitation
  • Circular External Skeletal Fixators(CESF) ( Ilizarov technique)
    • Most recent innovation in ESF technique in dogs and cats & also in large animals.
    • Developed by the Russian physician Gavriil A. Ilizarov
    • CESF consist of a series of complete and/or incomplete external rings that are interconnected by a series of threaded rods
  • Cont’d…..
    • These are modular systems which
    • can be assembled in numerous
    • configurations to
    • stabilize fractures and arthrodeses,
    • perform bone lengthening and transport
    • correct angular, translational and rotational deformities
    • Each ring is secured in position along the rod by placing a nut on either side of the ring
  • Cont’d….
    • Elongation of the frame allows for distraction osteogenesis in which regenerate bone is produced within the gap created when an osteotomy is distracted slowly and sequentially
    • “ Discontinuity of a skeletal segment necessarily triggers the repair process which will continue as long as integrity of both osteogenic tissue & its vascular supply is maintained”
    • Traditional CFs use small diameter wires, rather than pins, as fixation elements
  • Standard circular fixator frame for fracture management
  • Bones can be lengthened by streching a corticotomy 1mm a day The regenerate is composed of Microcolumns originating from both bone ends Radiograph of distraction Callus at 3 wks
  • Regenerated bone appears in the trailing pathway of a distracted bone segment in the dog treated with bone resection & distraction osteogenesis
  •  
  • Equipment
    • Wires
    • Rings
    • Wire fixation bolts
    • Threaded rods
    • Nuts
    • Wire tensioner & wrenches
  • Wires :
    • 1.0,1.2 or1.5mm diameter used in cats/ dogs
    • Olive wires- wires with a bead positioned midway along the wire
    • Provide interfragmentary compression & increase stability of frame construct
    • more the no. of fixation wires- more stability of fixation
    • Wire angles < 45°should be avoided
  • Olive wires
  • Rings
    • Partial ring & full ring
    • Five–eighth/stretch ring are used when rings would limit joint motion (elbow/stifle)
    • Partial rings -versatile
    • Full rings -more available holes for rods & wire, not versatile
    • ring diameter , axial stiffness, torsional & bending stiffness
    • Smallest ring allowing ≥2 cm distance b/w skin & inner circumference of ring selected
  • Wire fixation bolts
    • Cannulated wire fixation bolts –allow wire passage via a concentrically placed hole at base of bolt head
    • Slotted wire fixation bolts have an eccentric slot located under the bolt head & parallel to its long axis
    • Wire must be fixed without deformation
  • Frame construction
    • Threaded rods used to connect rings & form frame
    • Telescopic rods- hollow rods used as supports & connecting elements of ring
    • Frames are constructed so that one ring & its wires are placed at proximal end and another ring & its wires are placed at distal end of long bone
    • 2 additional rings placed so that their wires panetrate proximal & distal bone segments close to the fracture
  • Wire tensioner
  • Hybrid External Fixator
    • Combination of a ring & a linear fixator
    • Indicated for fractures with juxtaarticular bone segments
    • May be applied to radius,tibia,femur & humerus
    • Can also be used to stabilize corrective osteotomies for angular limb deformities
  • Larger transfixation wires can be combined with the use of rings & wires in a Hybrid frame
  • Clinical Applications of ESF
    • Fracture fixation
    • Radial & tibial
    • Humeral & femoral
    • Mandibular & maxillary
    • Stabilization of spinal fractures & luxations
    • Arthrodesis
    • Bone lengthening
    • Bone transport for bone defects
    • Angular limb deformity correction
  • Fixation of spinal fractures & luxations
    • Spinal arch external fixator components developed for spinal stabilization
    • Fluoroscopically guided percutaneous pin placement can be performed when applying external skeletal spinal fixation
  • Bone transport (limb salvage)
    • Method by which one or two segments of normal bone adjacent to a defect are slowly transported into the defect while new bone forms in the distraction pathway
    • Used in dogs with radial/tibial neoplasia or severe osteomyelitis with bone loss
    • A segment of bone is created with a corticotomy made 2-3 cm from one end of one of the main fragment
  •  
  • Acrylic external fixation
    • Acrylics are commonly used for the repair of fractures
    • The acrylic column acts as both the connecting
    • rod and transfixation pin-gripping device
    • Dental acrylic or hoof repair acrylic are suitable
    • It can be moulded over pins after curing to a
    • dough stage
    • Acrylic ESF offers the advantage of reduced
    • cost , improved versatility & simplified application technique when compared with kirschner ESF
  • Advantages of acrylic system
    • Ability to contour the connecting bar to match any fracture configuration
    • Fixation pins of any diameter may be used
    • Fixation pins do not have to be in the same longitudinal plane
    • Light in weight encouraging earlier return to function
  • cont’d……
    • Placing the positive profile threaded pin without the difficulties of passing them through clamps
    • Inexpensive system
  •  
  • Uses of acrylic fixators
    • Fixation of mandibular & maxillary fractures
    • Fixation of long bone fractures
    • Primary fixation device or intra-oral splint for mandibular & maxillary frcatures
  • Complications of ESF
    • Pin tract infection
    • Focal osteomyelitis
    • Ring sequestrum
    • Premature pin loosening
    • Instability at the fracture site
    • Pin breaking
    • Pin tract osteolysis
    • Pressure necrosis of skin
    • Iatrogenic bone fracture
    • soft tissue impalement
  • thank you