External Skeletal fixation (Lewis) Flashcards
1
Q
External skeletal fixation
A
- transosseous pins/wires incorporated into an extracorporeal frame
- can be used as primary or adjunctive stabilization
2
Q
External fixation: indications
A
- Comminuted fractures
- open fractures
- infected and nonunion fractures
- arthrodeses
- transarticular stabilization
- limb deformities
- gunshot wound
*Provides stable not rigid fixation
3
Q
External fixation:
Advantageous properties
A
- Applied either open or closed
- Stable constructs that counteract axial, bending and rotational forces
- can be used as adjunctive fixation to internal fixation
- latitude to make post-op adjustments
- encourage early weight bearing
- versatile and economical
4
Q
Types of external fixators
A
- Linear
- Acrylic
- Circular
- Hybrid
5
Q
External fixation:
Nomenclature: Type I
A
- Type I
- utilizes half-pin splintage
- pins pass through both cortices of bone, but only one skin surface
- Uniplanar and unilateral
- Pins loaded in contilever bending
- CIs cortex: near
- trans cortex: far
- utilizes half-pin splintage
* can be used above elbow and stifle
6
Q
External fixation
Nomenclature: Type II
A
- Utilizes full-pin splintage
- pins pass through both cortices and two skin surfaces
- Is uniplaner but bilateral
- Pins loaded in four-point bending
- holding both ends of the broom
*can’t use above the elbow, above the stifle
7
Q
External fixation
Nomenclature: modified type II
A
- Utilizes both half and full pin splintage
- Easier to apply with comparable stability
*can’t go above stifle or elbow
8
Q
External fixation
Nomenclature: Type III
A
- Utilizes both half and full-pin splintage
- Biplanar
- half and full-pins are oriented in pooposing planes
- Bilateral
- Applies mainly to linear and acrylic fixators
9
Q
External fixation
Biomechanics
A
- Surgeon must determine which construct is appropriate based on both biological and mechanical factors
- Type III
- very rigid constructs
- reserved for difficult, complex cases
10
Q
Fixation pins
A
- Weakest link in external skeletal fixation construct
- pin design and application have substantial effect on stability of bone-pin interface
- don’t use smooth pins
11
Q
Positive profile pins
A
- Superior stiffness and axial extraction characteristics
- can be site dependent
- Effective centrally positioned threads
- pre-drill pilot hole
- approximate the core diameter of fixation pin
12
Q
Kirschner-Ehmer (KE)
Apparatus
A
- Disadvantages
- Can’t place positive profile pins directly through clamps
- Pre-drilling pilot holes is difficult
- Difficult to place a series of parallel full-pin splintage pins
13
Q
IMEX SX External fixation system
A
- advantages
- innovative clamp design allows pre-drilling pilot holes
- allows variability in fixation pin diameter
- better mechanics
- disadvantages
- connecting system not radiolucent
- connecting clamps only accept pins of limited diameter
- connecting rod relatively weak
14
Q
IMEX SK ex fix
summary
A
- Inc stability
- should allow use of less complex frames
- eliminate need for double connecting bars on type I constructs
15
Q
Fixation pins
Application
A
- Place pins through small incisions
- don’t place pins through traumatic or surgical wounds
- Close surgical wounds prior to placing pins
- Avoid large muscle masses
