Specific ESF Applications and Possible Complications Flashcards
How many of tibia # are open and why?
50% - lack of soft tissue coverage
CARE when placing ESH in craniodistal tibia region - why?
Extensor tendons
When placing a ESF on the proximal medial tibia - care of?
Insertion of sartorius m.
Is open or closed reduction preferred for ESF?
Closed
Which of the following is the most common complication seen following application of an external skeletal fixator?
Implant failure
Malunion
Pin tract discharge
Delayed union
Pin tract discharge
What type of tibial # location are particualrly suited for ESF?
Diaphyseal
Which ESF type is recommended on lateral aspect? (Large muscle mass)
Type II
Tibia juxta-articular fractures suited for which fixation (2)
Circular
Hybird
Which of the following best describe a type 2 external skeletal fixator?
Bilateral biplanar
Bilateral uniplanar
Unilateral uniplanar
Unilateral biplanar
Bilateral uniplanar
What are pins inserted using?
ESF tissue protector
Place these steps in order when placing pins:
A) Tighten clamps
B) Adjust frame to achieve correct skin- clamp distance
C) Place connecting bar on medial and lateral aspects of limb
D) Add additional clamps as required
E) Drill additional pin holes via stab incisions using drill guide in clamp
F) Place pins using tissue protector
- C) Place connecting bar on medial and lateral aspects of limb
- D) Add additional clamps as required
- E) Drill additional pin holes via stab incisions using drill guide in clamp
- F) Place pins using tissue protector
- B) Adjust frame to achieve correct skin- clamp distance
- A) Tighten clamps
Why are frame options limited with the femur? (2)
- The proximity of the body wall
- The substantial soft tissue coverage present
Which configurations can be used to treat distal femoral and supracondylar fractures.
Circular-linear hybrid
What are considered the most appropriate locations for pin placement in the femur? (2)
- Greater trochanter
- Lateral epicondyle
With the femur - where are the more hazardous corridors? (2)
- Lateral
- Craniolateral
What does placement of pins in muscle bellies contribute to? (2)
- Pin tract irritation
- Morbidity
Which way are pins placed in the femur?
Normograde
When placing a pin in the femur -walk pin medially off the greater trochanter into..?
Trochanteric fossa
Transfixation pin placement – femur:
A) Transfixation pin diameter cf bone?
B) Avoid placing pins where..?
C) Preferred sites (2)
A) 20-30% of bone diameter
B) Muscle bellies
C) Greater trochanter + Lateral epicondyle
What are frame types of the upper limb limited by?
Body wall
What frames are useful methods for stabilisation of fractures of the humerus, particularly open fractures of the distal region? (2)
Type I or hybrid
What can be a useful adjunct to external fixation in the humerus, and can be tied into the frame to improve stability?
IM pins
Care must be taken when placing fixation pins in twhich part of the humerus, due to the presence of the radial nerve in close association with the brachialis muscle.
The distal third of the lateral diaphysis,
In cats, what is present on the medial aspect through which pass the median nerve and brachial artery?
Supratrochlear foramen
What angulation has been recommended when placing pins in the supracondylar region?
Angulation of the pin from distolateral to proximomedial
Which of the following statements are true?
A) The most proximal pin is placed into the craniolateral aspect of the humerus just distal to the greater tubercle.
B) The distal pin is then placed into the medial aspect of the condyle.
C) If a second pin is to be placed into the condyle, this should be placed just proximal to the lateral epicondyle and directed towards the medial epicondyle.
D) Type I fixators are useful to stabilise intercondylar fractures of the humerus with supracondylar comminution.
A) The most proximal pin is placed into the craniolateral aspect of the humerus just distal to the greater tubercle.
C) If a second pin is to be placed into the condyle, this should be placed just proximal to the lateral epicondyle and directed towards the medial epicondyle.
D) Type I fixators are useful to stabilise intercondylar fractures of the humerus with supracondylar comminution.
Where is the most proximal pin placed in the humerus?
Into the craniolateral aspect of the humerus just distal to the greater tubercle.
Humerus - where is the distal pin placed?
Lateral aspect of condyle
If a second pin is to be placed into the humerus condyle, this should be placed just proximal to the lateral epicondyle and directed where?
To medial epicondyle
What are useful to stabilise intercondylar fractures of the humerus with supracondylar comminution?
Hybrid circular-linear fixators
Hybird circular linear fixators allows adequate fixation into the small distal bone fragments, and the use of WHAT allows compression of the intercondylar fracture.
olive wires
Humerus:
The distal pin is then placed into the lateral aspect of the condyle. This is inserted slightly ? to the lateral epicondyle, and can be placed as a full or half-pin depending upon requirements.
craniodistal
Humerus IM pin with ESF is placed in which direction?
Normograde
Surgical stabilisation of a comminuted humeral fracture with a type Ia linear frame with IM pin tied-in:
From which approach?
Proximal or distal
Surgical stabilisation of a comminuted humeral fracture with a type Ia linear frame with IM pin tied-in:
For normograde placement of an IM pin in the case of distal humeral fractures when you want to apply the IM pin into the trochlea, ensure that a pin size is selected, so that it fits into the trochlea.
How is this done?
Measure the epicondylar rest width, which equals approximately 35% of the intramedullary canal width on a crania-caudal view at the level of 80% of the length of the shaft (from proximal to distal)
Surgical stabilisation of a comminuted humeral fracture with a type Ia linear frame with IM pin tied-in:
Proximally where is it inserted?
From proximal lateral greater tubercle – angle medially
Surgical stabilisation of a comminuted humeral fracture with a type Ia linear frame with IM pin tied-in:
Distally, where is it inserted?
from caudal-distal medial epicondyle.
Transfixation pin placement into the humerus:
Where is proximal pin cf to greater tubercle?
Distal
Transfixation pin placement into the humerus:
Where is distal pin cf to lateral epicondyle?
Craniodistal
Transfixation pin placement into the humerus:
Where is second distal pin cf to lateral epicondyle?
Proximal
What are the important structures to have in consideration when placing the second distal pin just proximal to Humerus lateral epicondyle? (2)
Radial nerve
Supratrochlear foramen (cats).
When placing 2nd distal humeral pin - how should this be angled?
Distolateral to proximomedial
Which aspect of a limb is highly amenable to external fixation?
Distal
What type of reduction + fixation can aid preserving poor blood supply in distal antebrachium
Close
Why is a classic type II linear ESF difficult proximal radius?
As medial to lateral pin placement difficult; narrow bone profile
What type of pin placement helps to maximise bone purchase with type Ib on the antebrachium?
Oblique
If the proximal radial fragment is insufficiently large to allow pin placement a proximal ulna fixation can be used, how does this function?
Strong attachments between radial head and uln
If the proximal radial fragment is insufficiently large to allow pin placement a proximal ulna fixation can be used:
restriction of pronation and supination can cause..? (2)
Some irritation and risk of early pin loosening
Which fixator is useful to periarticular # of the antebrachium?
Circular
Which rings may be advantageous in the proximal antebrachium to prevent elbow irritation?
Partial
What can help with reduction and improved stabilisation of the antebrachium?
IM ulna pin
Where in antebrachium must IM pins NOT be used?
Radius
What securing method must NOT be used in antebrachium?
Tie in
What ESF frame should not be used in large breed for antebrachium?
Type Ia
In toy breed dogs, use any ESF for radial fractures. What is there a high risk of ?
Non-union
When applying the proximal pins, drag and drop the structure that you need to be careful of. In the craniolateral radius area?
Radial n
When applying the proximal pins, drag and drop the structure that you need to be careful of. In craniomedial to caudolateral.
Extensor m
Which direction are distal pins placed in the antebrachium?
- Craniomedial/lateral to caudolateral/medial
- Medial to lateral possible if required
ESF complications. (7)
- Oedema
- Pin tract morbidity
- Pin loosening
- Pin breakage
- Bone fracture
- Delayed or non-union
- Neurovascular injury.
Postoperative oedema is normal to some degree. It is influenced by injury itself and surgery. How can it be prevented or minimized? (3)
Prevent by packing and bandaging post-op (including the foot).
Cold packing once bandage removed.
Physiotherapy.
How to reduce pin trat morbidity(4)
- Avoid skin-pin contact
- Use of safe corridors
- Good pin tract hygiene
- Assess loose/broken pins with x rays
With pin tract morbidity; how to obtain sample for C+S?
FNA/cytology
Where is pin morbidity more likely?
Pariarticular
Pin loosening is a race. What is meant by this?
Remember it is a race between fracture healing and the pins failing.
How to reduce pin loosening? (3)
- Minimise stress at pin bone interface
- Careful pin application (predrill high speed, apply slow speed, flush to keep cool).
- x ray q4-6 weeks
Thermal damage can lead to what?
Sequestrum
How to reduce pin breakage (5)
Ensure appropriate pin use.
Adequate pin sizing.
Sufficient number of pins.
Appropriate tension of wires in circular ESF.
Post-op exercise restriction.
When can bone # occur in pin fixing? (3)
Can happen intra/peri-operatively.
Can be delayed or happen following fixator removal.
Can fracture through the pin tract or at the original fracture.
How to reduce chances of bone #? (3)
Ensure correct pin sizing (not greater than 30% of bone diameter).
Ensure pin centred in bone.
Assess complete healing before removal!
How to reduce delayed/non-union? (6)
Appropriate case selection.
Appropriate frame selection.
Stiffness: insufficient/ excessive (less frequent).
Consider patient factors.
Consider fracture factors.
Ensure all clamps are tight at each recheck.
How common is neurovascular injury?
Rare
What reduces chances of neurovascular injury?
Safe corridors
How to reduce neuro vascular injury intra op? (2)
- Blunt dissect onto bone
- Tissue protector
What is the distance between the closest pins and # line with ESF?
1cm