Traumatic Amputations

Indications for Replantation

  1. Multiple Digits
    • Will allow early ROM and rehab = good predictable result
  2. Thumb
  3. Any digit in child
  4. Mid-Palmar amputation
  5. Any proximal amputation
    • Results with reimplantation better than prosthetic
    • Sensibility and coordinated function
  6. Single digit distal to FDS insertion (within flexor zone 1)
    • Relative indication
    • Will be able to rehab better than proximal amputation

Contraindications

  1. Single digit proximal to FDS (flexor zone 2)
  2. Crush injury
  3. Segmental amputation
  4. Prolonged ischaemic time

Care of the Amputated Part

  • Place in saline-soaked gauze within a plastic bag in an ice bath
  • Transport at 4 degrees is ideal

Viable Ischaemic Time

  • Viable time is less for body parts containing muscle
  • Muscle very sensitive to ischaemia
    • Results in increased infection risk and necrosis
  • For Hand:
    • 12 hours warm ischemia and 24 hours cold ischemia time
  • Proximal to carpus:
    • 6 hours warm ischemia and 12 hours cold ischemia time

Order of Replantation for Hand and Digits

  1. Digit
    • Thumb: Provides 40% hand function
    • Middle
    • Ring
    • Little
    • Index
  2. Structure
    • Bone
    • Extensor Tendon
    • Flexor Tendon
    • Artery
    • Nerve
    • Vein
    • Skin

Technique

  • For multiple digital amputation use:
    • Structure by structure:
      • Faster
      • Higher viability rate
    • Digit by digit:
      • Slower
    • Transpositional Replantation:
      • Most viable digit re-planted to most important finger
      • Not as good as anatomic replantation if possible

Other Technical Points

  • Sympathetic block in axilla
  • Abx and tetanus cover
  • Dedicated replant team with practice in the lab gives best results
  • Use longitudinal mid-lateral incisions
  • Shorten bones before fixing – reduces tension on soft tissues
  • 10-0 nylon adventitial repair to artery
  • 10-0 epineureal repair for nerves – graft if irreparable (MCNF)

Post-operative Management

  • Hydrate patient
  • Keep warm
  • Anticoagulation:
    • Careful not to overdose – may cause haematoma
  • Avoid vasopressors (nicotine, caffeine, etc.)
  • Monitor O2 sats and skin temperature:
    • Drop in temperature by 2 degrees in 1 hour or absolute temperature of 30 degrees indicates unsatisfactory perfusion

Complications

  • Failure:
    • Early:
      • Arterial thrombosis due to persistent vasospasm
      • Administer heparin, warm finger, stellate ganglion blockade
    • Late (>12 hours):
      • Venous thrombosis/congestion
      • Can be treated with leeches or heparin-soaked gauze
  • Re-perfusion injury:
    • Ischaemia induces hypoxanthine conversion to xanthine
    • Allopurinol given to prevent this
  • Myonecrosis and renal failure
  • Infection
  • Hypersensitivity
  • Cold intolerance

Results of Replantation

  • Best predictor of survival:
    • Mechanism of injury (sharp better than blunt)
  • Following this:
    • Ischaemic time is the main factor (<8 hours = optimal results)
  • Function:
    • Digital replantation can expect 50% ROM and 10mm 2PD

Forearm and Arm Replantation

  • Establish arterial flow first if possible
  • Minimizes warm ischaemia time
  • Prophylactic fasciotomies for all patients

Ring Avulsion Injuries

  • Avulsion of soft tissues and NV structures from finger

Urbaniak Classification

Type 1

  • Circumferential laceration
  • NV viable
  • Treat as soft tissue injury

Type 2

  • Vascular insufficiency
  • Replant if bone/tendon intact (i.e., no other injuries)
  • If vascular injury in addition to bony injury - amputate

Type 3

  • Complete avulsion with bone exposed – amputate

Nail and Finger Tip Injuries

Epidemiology

  • Very common injuries
  • Long finger most common

Mechanism

  • Crush:
    • May include tuft fracture
    • Nail matrix avulsions
    • Nail plate avulsions
  • Sharp:
    • Usually soft tissue loss
    • May expose bone or amputate bone

Nail Structure

Nail Plate

  • Composed of keratin
  • Arises from Germinal matrix proximal to nail fold

Germinal Matrix

  • Contributes 90% of nail thickness

Sterile Matrix

  • Adherent to nail plate
  • Contributes 10% of thickness by producing keratin

Paronychium

  • Skin on lateral edges of nail

Hyponichium

  • Finger tip tough skin just below distal nail plate edge
  • Barrier to micro-organisms

Eponychium (cuticle)

  • Skin at proximal nail plate

Lunula

  • Demarcation between germinal and sterile matrix seen through plate

Goals of Treatment in Finger Tip Injuries

  1. Maintain length where possible
  2. Sensate finger pulp
  3. Prevent contracture
  4. Restore full function

Management of Nail Bed Injury Without Soft Tissue Loss

  • Subungal haematomas can be drained with a needle if <50% nail plate
  • If large haematoma:
    • Remove nail plate
    • Inspect, debride and repair underlying sterile or germinal matrix
    • Early surgical treatment of nail bed injuries gives best results
    • Replace nail plate below eponychium to guide new nail growth
  • If significant matrix loss, consider:
    • Matrix transfer from 2nd toe or adjacent finger
  • Nail re-growth takes 3-6 months

Complications

  • Hook nail
  • Nail ridging
  • Cold hypersensitivity – 50%

Management of Finger Tip Injury with Soft Tissue Loss

Classification

  • Important as it guides coverage choice
  • Descriptive – refers to orientation of residual stump:
    • Transverse
    • Volar oblique
    • Dorsal oblique
    • Lateral Oblique
  • Bone exposed or not

No Exposed Bone, Pulp <1cm Loss

  • Secondary intention healing
  • Full thickness skin graft:
    • Better sensibility, appearance, and durability

Exposed Bone

  • Volar Oblique Injury:
    • Cross finger flap
    • Thenar flap (for index or long finger only)
  • Transverse or Dorsal Oblique Injury:
    • Atasoy VY advancement
    • Kutler VY advancement (smaller – two flaps meet in the middle)
    • Reverse cross finger flap
  • Transverse or Volar Oblique Thumb Injury:
    • Moberg advancement – for defects <2cm
  • Dorsal Thumb:
    • Kite flap
    • Reverse cross finger flap

Flap Types

  • Cross finger; Atasoy VY; Kutler VY; and Thenar flaps

Soft Tissue Coverage & Microsurgery

Reconstructive Ladder

  1. Primary closure
  2. Secondary intention
  3. STSG (Split Thickness Skin Graft)
  4. FTSG (Full Thickness Skin Graft)
  5. Local Flap coverage
  6. Free Flap coverage

Healing by Secondary Intention

  • Granulation tissue, epithelization, contracture of skin
  • Not advised if tendon, nerve, or bone is exposed in the wound bed

Skin Grafting

  • Skin grafts receive their blood supply by diffusion from the wound bed
  • Failure of graft to take is due to:
    • Shear stress and hematoma formation

Split Thickness Skin Graft

  • Preferred for dorsal hand wounds
  • Meshing increases surface area and prevents hematoma accumulation
  • Typical donor site: anterolateral thigh
  • Thickness:
    • 0.005-0.03 inches – 0.015 common
  • Thicker grafts contain hair follicles and sweat glands
    • May or may not be preferred

Full Thickness Skin Graft

  • Higher chance of viability
  • Better re-innervation
  • Better cosmetic appearance
  • Less scar contraction
  • Preferred for palmar defects
  • Typical donor site: volar wrist or forearm

Flaps

  • Tissue unit containing a blood supply taken from a donor site and re-implanted into the wound bed
  • The donor site from which the flap is taken can be closed primarily or skin grafted
  • Flaps may be classified by:
    • Tissue type
    • Blood supply
    • Donor site location

Classification by Tissue Type

  • Cutaneous: contains skin and subcutaneous tissue
  • Fasciocutaneous: contains skin, SC tissue, and fascia
  • Musculocutaneous: skin, SC tissue, fascia, and muscle
  • Osteocutaneous: skin, SC tissue, fascia, muscle, and bone

Classification by Pattern of Blood Supply

  • Axial Pattern Supply Flap:
    • Blood supply is based on a named artery and its draining vein
    • Allows larger flaps to be grafted
    • More likely to take
    • Lower infection rate
  • Random Pattern Flap:
    • Vessels within the flap are allowed to micro-anastomose with those in the wound bed

Classification by Donor Location

Local Flaps

  • Transposition Flap:
    • Geometric in design and designed to close or lengthen a wound without having to actually free-raise any tissue
    • Classic example: Z-plasty – used for:
      • Lengthening a scar (e.g., a scar within a flexion contracture)
      • Preventing formation of contracture (crossing creases)
      • Re-orientating a cosmetically bad scar (soft indication)
      • All limbs must be equal length
      • Full thickness skin flap raised
      • Tissues undermined enough to allow mobilization of limbs
      • Triangular flaps transposed around each other
      • 30-degree angle gives a 25% lengthening
      • 45-degree angle gives a 50% lengthening
      • 60-degree angle gives 75% lengthening
  • Rotation Flaps:
    • Random pattern with regard to blood supply
    • Length of flap should not exceed width of base
  • Advancement Flaps:
    • VY plasty and Moberg flaps
    • Proceed in a straight line to fill the defect
  • Axial Flag Flaps:
    • Based on the dorsal digital artery
    • Can be homodigital (used to fill defect on same digit) or heterodigital (transferred to an adjacent digit)
  • Fillet Flap:
    • Tissue taken from an amputated digit not for replantation

Distant Flaps

  • When there is inadequate local tissue for coverage
  • Example: placement of hand into a groin or abdominal pouch

Free Flaps

  • Distant axial pattern flap based on a named AV blood supply
  • Transferred and re-anastomosed to the local vasculature
  • Lat Dorsi Flap (Thoracodorsal artery) typical
  • Serratus Anterior (subscapular artery branch)

Flap Selection in the Hand

Finger Tip – Volar

  • VY Advancement

Finger Tip – Volar Oblique or Dorsal

  • Cross Finger Flap (older patients)
  • Thenar flap (young patients)

Volar Proximal Finger

  • Cross Finger Flap

Dorsal Proximal Finger

  • Reverse Cross Finger

Volar Thumb

  • Moberg Advancement if <2cm defect
  • FDMA if 2-4cm
  • Neurovascular Island Flap if >4cm

Dorsal Thumb

  • FDMA (First dorsal metacarpal artery flap)

1st Web Space

  • Z Plasty

Dorsal Hand

  • Groin Flap
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