Upper Limb - Trauma

Question 1

What are the relative contraindication for replantation?

Answer 1

LOCAL
Mechanism of injury - crush or avulsion
Gross contamination
Prolonged ischaemia time
Segmental injury
Previous injury of amputated part
Single digit in zone 2

PATIENT
Polytrauma with other life threatening injuries
Comorbidities e.g. Diabetes, mental instability
Smokers

Question 2

What is the Urbaniak classification of ring avulsion injuries?

Answer 2

Urbaniak classified ring avulsion injuries in 1981
3 types
I - circulation adequate
II - circulation inadequate
III - complete degloving/amputation

Traditionally held view was that class III injuries may be best managed by amputation
- challenged by Kay et al 1989

Question 3

What is the revised classification of ring avulsion injuries as described by Kay et al (1989)

Answer 3

Kay classification:
I - circulation adequate +/- skeletal injury
II - circulation inadequate, NO skeletal injury (a-arterial / v-venous)
III - circulation inadequate, WITH skeletal injury (a-arterial / v-venous)
IV - complete amputation

Classes relate to severity and prognosis
Increased severity with increasing class injury
Even class IV injuries are salvageable
BUT
Increasing complexity/no.of procedures & complications with salvage in higher classes
Higher chance of salvage if either arterial OR venous compromise only compared to pts with both
Salvage is independent of fracture BUT better rehab in pts without skeletal injury

Question 4

What are the relative indications for replantation?

Answer 4

Thumb
Multiple digits
Proximal injury (or distal to FDS insertion)
Child
Puts who MUST have 10 digit hands e.g musician

Question 5

What is my surgical plan for replantation?

Answer 5

Pre-op:
Standard upper limb trauma history and assessment
X-rays
Decide on whether replantation is suitable
- consider WOUND and PATIENT factors
Ensure amputated part stored & transported appropriately
Pt optimisation incl. antibiotics, tetanus etc
Consent pt for all possibilities

Intra-op:
GA +/- tourniquet
2 team approach
1. Exploration and preparation of amputated part (this can even be commenced before pt arrives in theatre)
2. Exploration and preparation of stump
Consider:
- skin incisions and access ?where is my anastomosis going to be
(usually longitudinal mid axial incisions work well)
- adequate debridement
- exploration and preparation/tagging of neurovascular structures
? red streak sign - bruising over NV pedicle
? ribbon sign - corkscrew appearance of vessels following avulsion
? spurt test - proximal bleeding
- bony shortening and preparation for bony fixation
- preparation of flexor/extensor tendons

Then if suitable proceed with replantation
Intra-op heparin 5000u
Sequence:
- Osteosynthesis - to achieve stability
- Flexor tendon repair
- Arterial anastamosis - consider need for vein grafts
- Nerve coaptation
Then turn hand over and work on back
- Extensor tendon repair
- Venous anastomosis (ideally 2 if possible)
NB. If no suitable veins then options incl removing nail plate and scraping sterile matrix/stab incision to periungual area + topical heparin to encourage bleeding OR leech therapy
- Skin coverage

NB. The most important predictive factor of successful revascularisation is good surgical technique!

Special considerations in macroreplantation:
If delayed ischaemia time + macroreplant consider temporary shunt first before osteosynthesis
Considerable bone shortening usually required - facilitates primary neurovascular repair
After arterial repair allow venous drainage before venous repair to flush out toxic metabolites
Fasciotomies
Second look at 48hrs to reassess muscles

Post-op:
Flap monitoring unit (HDU level care)
Hourly flap obs - colour, temp, perfusion +/- handheld doppler
Bair Hugger
Analgesia
Fluid balance
Post op thromboprophylaxis - 80% risk of thrombosis in first 48hrs

Question 6

What is the evidence for replantation?

Answer 6

Thumb - 62% survival but equivalent functional outcome between replant and revision amputation (Goldner 1990)
Also better survival and ROM with great toe transfer (Rosson et al 2008)

Zone 1 - 78% survival (Kim et al 1996) to 92% survival (Hahn et al 2006)

Zone 2 - 56% survival (Trom et al 1995) but in comparison with amputation have longer treatment, more time off work and only 44% have good function at 1yr v 90% with amputations (Goel et al 1995)

Zone 3/4 - 81% survival with good functional results (Daoutis 1992)

Proximal replants - functional results are superior to revision amputation and prosthesis (Graham et al 1998)

Question 7

Tell me about the PIA flap?

Answer 7

PIA = Posterior interosseous artery flap
Septocutaneous flap
Based on posterior interosseous artery - branch of common interosseous division of ulna artery
Enters posterior forearm between heads of supinator and APL
Runs in septum between EDM/ECU
Runs with PIN
Anastamoses with perforating branch of AIA at wrist

May be raised antegrade or retrograde
Antegrade will cover olecranon
Retrograde (reverse flap) will cover defects of dorsal thumb/hand to incl MCPJ’s and proximal phalanx or anterior wrist/palm

Avoid in pts with significant wrist injury - may have PIA thrombosis

Markings
- arm held in 90 degrees elbow flexion
- line drawn between lateral epicondyle and DRUJ
- vessel emerges at junction proximal/middle thirds - largest perforator found here
- flap usually templated over middle third of line
NB. proximally can extend up to 2-3cm beyond where vessel emerges to include main perforator and distal limit is 3-4cm proximal to DRUJ to protect dorsal branch of ulna nerve and anastamosis with AIA
- pivot point is at this mark 3cm proximal to DRUJ

Dissection

• start at radial border
• subfascial dissection until reach EDM
• septocutaneous perforators are identified and followed in septum to main PIA trunk
• ulna part of flap raised to complete flap dissection
• dissection then proceeds proximal to distal ligating muscular branches
• raise septum with deep fascia
• care to avoid damage to PIN and motor branches
• linear extension of incision distally and pedicle traced back to pivot point
• subcutaneous tunnel created to pass flap through

Question 8

Tell me about the Becker flap?

Answer 8

Becker flap
Axial flap
Based on dorsal branch or ulna artery
Given off ~2cm proximal to pisiform
Passes under FCU before splitting into proximal, middle and distal branches (middle branch supplies overlying skin)

Raised retrograde - will cover defects of dorsum/palmar surface of wrist and ulna side of dorsum hand/palm

Markings
- vessel emerges ~2-4cm proximal to pisiform - this is the pivot point
- flap templated along ulna border of distal forearm along axis of ulna
NB. Volar extent is PL and dorsal extent is EDC to RF

Dissection

• start with incision ~2cm proximal to pisiform to identify vessel
• ensure flap is centred correctly
• subfascial dissection proceeds from proximal to distal