External skeletal fixation (internal fixation)

Question 1

What must there be for external skeletal fixation to be effective?

Answer 1

three tranfixation pins in the proximal fragment and three pins in the distal fragment and each pin must fully pass through both cortices of the bone (fewer if IM pin as well)

Question 2

What are benefits of external skeletal placement and removal?

Answer 2

1. relatively sparing of the blood supply

2. usually removal does not require second surgery

Question 3

What are benefits of external skeletal placement and removal?

Answer 3

1. relatively sparing of the blood supply

2. usually removal does not require second surgery

Question 4

What is the technique of external skeletal fixation?

Answer 4

A bone is splinted by passing fixation from the outside of the body through both cortices of the bone in a more or less transverse fashion. Fixation pins are then attached to at least one external connnecting bar. can be combined with IM pin

Question 5

What are transfixation pins?

Answer 5

things that stick into the bone, attach to connecting bars (smooth or threaded–better grip)-

Question 6

What is negative vs positive profile?

Answer 6

in negative profile the threads are cut into the pin. in positive profile the thread is added to the pin

Question 7

What half pins vs full pins? (transfixation pins)

Answer 7

half pins only attach to one connecting bar (end threaded)

full pins have both ends attached to connecting bars (centre threaded)

Question 8

What are clamps?

Answer 8

the grip the transfixation pins as well as the connecting bar.

Question 9

What are clamps?

Answer 9

they grip the transfixation pins as well as the connecting bar. (can use epoxy etc if no clamps)

Question 10

What are connecting bars?

Answer 10

an outside of the limb scaffold that you attach the transfixation pins to.

Question 11

What are the advantages of rod and clamp system?

Answer 11

1. adjustable after you put it in place

Question 12

What are the disadvantages of rod and clamp systems?

Answer 12

1. the transfixation pins have to be in a straight line and of similar size
2. the fracture fragments may not give enough room to put enough pins

Question 13

What are advantages of acrylic connecting bars?

Answer 13

1. tansfixation pins can be of varying sizes, don’t need to be in a stright line

Question 14

What is the disadvantage of acrylic connecting bars?

Answer 14

not adjustable

Question 15

What is a cool trick that can do for birds, puppies, cats?

Answer 15

once transifxaiton pins are placed, bend them and the IM pin if present so parallel to limb, then wrap in acrylic putty/thermoplastic

Question 16

What are the 4 classic types of ESF configuration?

Answer 16

1. Type Ia fixator
2. Type IIa fixaor
3. Type Ib fixator
4. Type III fixator

Question 17

What are the 4 classic types of ESF configuration?

Answer 17

1. Type Ia fixator
2. Type IIa fixaor
3. Type Ib fixator
4. Type III fixator

Question 18

What is type Ia fixator?

Answer 18

a unilateral uniplanar fixator–half pins and one bar. weakest configuration. in young animals and perfectly reduced transverse fractures

Question 19

what is a type II fixator?

Answer 19

a bilateral uniplanar fixator. two full pins, two connecting bars and some half pins (more pins, stronger apparatus)

Question 20

What is a type Ib fixator?

Answer 20

a unilateral biplanar fixator–two type Ia fixators at 90 degrees. even stronger if have a bar between the connecting bars

Question 21

what is a type III fixator?

Answer 21

a bilateral biplanar fixator. type II fixator + type Ia fixator. very very strong. But the bone may not get loaded and thus not heal so not used that much

Question 22

What is an IM pin-ESF tie in?

Answer 22

use an IM pin and leave it long. add half pins and have the pins and the IM pins joined to a connecting bar

Question 23

What is transfixation casting?

Answer 23

adding transfixation pins to a cast to hold thhe proximal fragment up to prevent compression. most often large animal

Question 24

What is circular external skeletal fixation

Answer 24

use rings connected with rods.

thin wires under tension run through the bones

Question 25

What is circular external skeletal fixation

Answer 25

use rings connected with rods.

thin wires under tension run through the bones. Can hae hybrids with regular ESF

Question 26

When are circular external skeletal fixators used?

Answer 26

1. when there are short proximal or distal fragments to be dealt with.
2. can grow new bone by distraction osteogenesis

Question 27

What are the “rules” of ESF pins?

Answer 27

1. 3-4 pins per fragments (1-2 if have IM in)
2. predrill all positive profile threaded pins while a guide hole smaller than threads
3. if using smooth pins, angle them, if positive profile, angle or straight
4. ALL transfixation pins (includes half pins!!!) must FULLY penetrate BOTH cortices of the bone
5. connecting bars should be a finger’s width from the skin
6. transfixation pins are placed through stab incisions in the skin. cover the pad and soft tissue around pins with Robert Jones bandage until 5 days (granulation tissue)

Question 28

What are the advantages of ESF (6)

Answer 28

1. minimal blood supply disruption
2. hardware removal can be done under sedation without surgery
3. fixator removal can be done in stages to gradually transfer forces back to bone
4. since ESF placement does not require anatomic reconstruction of bone, it can be used to treat highly comminuted fractures
5. good way to deal with fractures with very short proximal or distal fragments
6. sometimes cheap

Question 29

What are the advantages of ESF (6)

Answer 29

1. minimal blood supply disruption
2. hardware removal can be done under sedation without surgery
3. fixator removal can be done in stages to gradually transfer forces back to bone
4. since ESF placement does not require anatomic reconstruction of bone, it can be used to treat highly comminuted fractures
5. good way to deal with fractures with very short proximal or distal fragments
6. sometimes cheap

Question 30

What are the disadvantages of ESF?

Answer 30

1. not good for bones that are surrounded by muscle, trunk

2. hardware must be removed!

Question 31

What is ESF a particularly good choice for?

Answer 31

1. open fractures and degloving injuries
2. highly comminuted fractures (if have IM pin tie in)
3. fractures with short proximal or distal fragments
4. stabilization of corrective osteotomies
5. distraction osteogenesis