Microsurgery Flashcards

1
Q

What are the goals of tx of fingertip amputations?

What is the prognosis for tx?

A
  • Sensate Tip
  • Durable Tip
  • Bone support for nail growth

Prognosis

  • Improper tx may result in stiffness adn longterm functional loss
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2
Q

Can you draw/describe the anatomy of the finger tip?

A
  • Eponychium- soft tissue on dorsal surface just proximal to nail
  • Paronychium- lateral nail folds
  • Hyponychium- plug of kerabtinous material situated beneath the distal edge of nail where nail bed meets skin
  • Lunula- white portion of proximal nail, demarcates sterile from germinal matrix
  • Nail bed
    • Sterile matrix- nail adheres to nail bed
    • Germinal matrix- proximal to sterile matrix, responsible for 90% nail growth
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3
Q

What is the aetiology of amputation?

A
  • Avulsion
  • Laceration
  • Crush
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4
Q

What do you see on examinatio of an amputated finger tip?

A
  • Characteristics of laceration
  • presence/absence of exposed bone
  • range of motion- felxor/extensor involved
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5
Q

What investigations useful for amputation of finger tip?

A
  • Xray- ap and lateral to assess Bony involvment
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6
Q

Describe the tx of finger tip amputations?

A

Non operative

  • Healing by secondary intention
    • adults/children with no bone/tendon exposed with <2cm skin loss
    • children with exposed bone

Operative

  • Primary closure- revision amputation
    • finger amputation w exposed bone and ability to rongeur bone proximally without compromising bony support to nail bed
  • Full thickness skin graft from hypothenar region
    • Fingertip ampuation with no exposed bone and >2cm tissue loss
  • Flap Reconstruction
    • exposed bone/tendon where reongeuring bone proximally is not an option
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7
Q

Describe the technique for secondary intention?

A
  • initial tx with irrigation and soft dressing
  • After 7-10 days saok in water-peroxide solution daily followed by application of soft dressing adn fingertip protector
  • complete healing takes 3-5 weeks
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8
Q

Describe the technique for full thickness skin grafting from hypothenar region?

A
  • Split skin grafts not used as
    • Contractile
    • Tender
    • Less Durable
  • Donor site is closed primarily
  • Graft is sutured over defect
  • Cotton ball secured graft helps maintain coaptation with underlying tissue
  • Ball removed after 7 days
  • Range of motion encourage after 7 dyas
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9
Q

Describe the technique for revision amputation?

A

Primary closure with removal of exposed bone

  • Must ablate remaining nail matrix
    • prevent formation of irrating nail remnants
  • If flexor/extensor tendon insertions can’t be preserved disarticulate at DIPJ
  • transect digtial nerves and remaining tendoms proximal as possible
  • Plamar skin is brought over bone and sutured to dorsal skin
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10
Q

Can you describe the flap types available for Finger tip- to DIPJ ?

A
  • Straight/Dorsal Oblique lacerations
    • V-Y Advancement
    • Digital Island Artery- best axial pattern flap
  • Volar Oblique laceration
    • Cross finger Flap if >30 yrs- less stiffness
    • Thenar Flap if <30 yrs- improved cosmesis
    • Digital Island artery
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11
Q

Can you describe the types of flap available for volar proximal finger?

A
  • Cross finger flaps if > 30 years
  • Axial flag flap from long finger
  • Leads to less stiffness - X finger flaps
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12
Q

Can you describe the types of flap available for dorsal proximal finger and MCP lesion?

A
  • **Reverse Cross FInger **
  • Axial FLag flap from long finger
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13
Q

Can you describe the types of flap available for volar thumb lesion?

A
  • Moberg Advancement Volar flap if <2cm
  • First Dorsal Metcarpal Artery flap FDMA if >2cm
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14
Q

Can you describe the types of flap available for dorsal thumb lesion?

A
  • First Dorsal Metacarpal Artery Flap
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15
Q

Can you describe the types of flaps available for first web space lesions?

A
  • Z plasty with 60 degree flaps
    • can increase length by 75%
  • Posterior interosseous fasciocutanoeous flap
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16
Q

Can you describe the flaps types available for dorsal hand?

A
  • Groin flaps
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17
Q

What are the complications of flaps?

A
  • Flap failure
    • inadequate blood flow
    • vasospasm -> thrombosis at anastomosis
  • Hook nail deformity
    • Tight tip closure
    • insufficient bone support
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18
Q

What is the epidemiology of upper extremity amputations?

A
  • Trauma
  • 90% occur after trauma
  • 4:1 male cf female ration
  • most occur at level of digits
  • mechanism of traumatic amputation
    • Sharp dissection
    • Blunt dissection
    • Avulsion
    • Crush
19
Q

What is the imortant history and signs of amputation?

A

Hx

Timing of injury

  • type & location of amputation
  • preservation of amputated tissue
  • PMhx

O/E

  • Stump examination
  • zone of injury/ tissue viability/supporting tissue structures/contamination
  • Amputated portion inspected
    • level, segemental injury/ bone/soft tissue damage/ contamination
20
Q

What are the indications for replantation post trauma?

A

Primary

  • Thumb
  • Multiple digits
  • wrist level or proximal wrist
  • Almost all parts in children

Relative

  • Individual digits distal to the insertion of Felxor digitorium superficialis- zone 1
21
Q

What are the contra- indications for replantation post trauma?

A

Primary

  • Single digit proximal to FDS - zone 2
  • mangled limb/crush injury
  • Semgental amputation
  • prolonged ischaemic time

relative

  • Medically unstable patient
  • disabling psychiatric illness
  • tissue contamination
22
Q

Describe the transport of amputated tissue?

A
  • Keep with patient
  • Wrapped in gauze in lactate ringers solution
  • Placed in sealed plastic bag and placed in ice water- avoid direct contact with ice/dry ice
  • Wrap, cover and compress stump wiht moisten gauze
23
Q

Describe the time to reimplantation?

A
  • proximal to carpus
    • warm ischaemic time <6 hours
    • cold ischaemic time <12 hrs
  • Distal to carpus ( digit)
    • warm ischaemic time <12 hours
    • Cold ischaemic time <24 hrs
24
Q

Can you describe the operative sequence of replantation?

A
  1. Bone
  2. extensor tendon
  3. Flexor tendons
  4. Arteries
  5. Veins
  6. Nerve
  7. Skin

BEFAVNS

25
Q

Can you describe the finger oder for reimplantation?

A
  • Thumb
  • Middle
  • Ring
  • Small
  • Index
26
Q

How is reimplantation achieved for mutliple digits?

A
  • Structure by structure most efficient
  • Digit by digit takes the most time
27
Q

Describe the post operative care for reimplantated digits?

A
  • Environment
    • Warm 80F
    • avoid caffine, chocolate, nicotine
  • Monitor replant
    • Skin temperature- most reliable, concern >2o drop in < 1 hour or temp below 30oC
    • Pulse oximetry <94% - vascular compromise
  • Anticoagulation
    • adequte hydration
    • medications aspirin, heparin
  • Arterial insufficiency
    • release constriction bandages
    • place extremity in dependent position
    • consider heparinisation
    • consider stellate ganglion blockade
    • early surgical exploration
    • thrombosis secondary to vasospasm is most common cause of early implant failure
  • Venous congestion
    • elevate extremity
    • leech application
      • release Hirudin- powerful anticoagulant
      • aeromonous hydrophila infections can occur
      • Heparin soaked pledgets if no leeches
28
Q

Describe the complications of reimplantiation?

A
  • Reimplantation failure
    • within 12 hrs- arterial thrombosis from vasospasm
  • Stiffness
    • 50% of total motion of normal digits
    • tenolysis is most common secondary procedure
  • Myonecrosis
    • > in major limb reimplantation cf digit
  • Myoglobinuria
    • muscle necrosis in larger implants
    • can lead to renal failure-> fatal
  • Reperfusion injury
    • ischaemia induced hypoxanthine conversion to xanthine
    • Allopurinol to decrease xathine production
  • Infection
  • Cold intolerance
29
Q

What is the most important factor in influencing immediate and late outcome of amputations?

A
  • Type of Injury
30
Q

Describe the regions of thumb reconstruction?

A
  • Region A
    • Primary closure
    • Toe to thumb
    • local flaps
  • Region B
    • Web Deepening
    • Metacarpal lengthening
    • Toe to thumb
  • Region C
    • Toe to thumb
    • Osteoplastic thumb reconstruction
    • Dorsal rotational flap
  • Region D
    • Pollicization
31
Q

What does thumb reconstruction require?

A
  • An intact CMCJ that is stable but also **appropriately functional **
32
Q

Describe the different tx of thumb reconstruction?

A
  • Toe to thumb procedure
    • Great toe recieves blood supply from 1st dorsal metatarsal artery & dorsalis pedis
    • morrison/wrap around allows for maintaince of length if hallux. Size and appearance are best replicated.
    • 2nd MT is not suitable for transfer
  • Web Deepening
    • ​Z plasty ( 2/4 flaps)
      • ​2 flaps provide > depth
      • if complete at 45o - relative length increase by 50%, 60o 75%
    • Brand Flaps
      • Index finger used to provide a full thickness
      • can close donor site primarily
    • Dorsal rectangular flaps
      • taken from dorsum of metacarpals
      • may require skin grafting
    • Arterilalized palmar flap
      • may use axial ( local) or island flap ( distal)
  • ​Osteoplastic reconstruction
    • ​iliac crest is used to establish mechanical length to the thumb
    • an island flap from the radial aspect of the 4th ray is combine dwiht reverse radial forearm flap to aid coverage.
33
Q

What is ring avulsion injuries?

A
  • Sudden pull on a ring finger results in severe soft tissue injury ranging from circumferential soft tissue laceration to complete amputation
  • Skin. nerves , vessels are often damaged
34
Q

Describe the epidemiology of ring avulsion injuries?

A
  • Incidence 150,000 incidents of amputation & degloving in us pa
  • 5% of upper limb injuries
  • Usually involves one digit - ( ring)
  • Risk factors
    • working with machinery
    • wearing a ring
35
Q

What is the aetiology of ring avulsion injuries?

A
  • Patients catch wedding ring or finger on moving machinery or protruding object
  • Long segment of MACRO & MICRO Vascular injury from crushing, shearing and avulsion
36
Q

What is the prognosis of avulsion injuries?

A
  • Outcomes of injury
    • Extent of injury is greater than what it appears
    • Poor prognosis because of long segment vascular injury
  • Outcomes of tx
    • Advances in interposition graft techniques have improved results with ring avulsion replantation
37
Q

How long will avulsed digits last for?

A
  • As devoid of muscle avulsed digits will survive >12 h if cooled
  • Skin is the strongest part - once torn the remaining tissue quickly degloves
38
Q

Can you describe the name and classification system of ring avulsion injuries?

A
  • Urbaniak Classification
  • Class 1= (80N) Circulation adequate->standard bone and soft tissue care
  • Class 2-=Circulation inadequate-> vessel repair
  • Class 3= ( 154N)Complete degloving or complete amputation-> amputation
39
Q

what are the signs and symptoms of ring avulsion injury?

A
  • Hx
    • work with machinery, caught in door
  • Symptoms
    • Pain
    • Bleeding
    • Lack of sensation at tip
  • OE
    • Inspect- irrigate wound adn inspect for avulsed vessels, damaged tendons, nerves, skin edges
    • Staggered injury pattern
      • prox skin avulsion from pipj->base of digit
      • Distal bone fracture or dislocation- distal to pipj
40
Q

What investigations are helpful in dx of ring avulsion injuries?

A
  • Xrays of both parts as amputated part may have bone!
41
Q

Describe the tx of ring avulsion injuries?

A
  • Initally
    • Place amputated part in bag with saline moistened gauze , follwed by bag of ice
    • Antibiotics and tetanus prophylaxis

Operative

  • Reimplantation +/- Vein graft, DIPJ fusion
    • for disruption of venous drainage
    • disruption of venous/ arterial flow- revascularisation
    • Intact PIPJ & FDS insertion
  • ​Complete ampuation ( esp distal to PIPJ/FDS is relative CI to reimplantation

  • Revision Amputation
    • complete degloving
    • bony injury with nerve and vessel injury
    • bony amputation proximal to FDS or proximal to PIPJ
      • reimplantation likely-> poor hand function
      • consider revision amputation/ray amputation
42
Q

What are the outcomes of replantation+/- vein graft , dipj fusion for ring avulsion injuries?

A
  • Survival
    • lower survival for avulsed digits 60% cf finger reimplantation in general 90%
    • Lower survival for complete 66% vs incomplete avulsion replantation
    • Lower survival for avulsed thumb than finger
      • surgeons attempt technically difficult rhumb where conditons are not favourable cf digits
  • Sensibility
    • most achieved Protective Sensibilty 2PD 9mm
    • Better sensibility when incomplete avulsion replantation than complete
  • Range of motion
    • Average total arc of motion (TAM) is 170-200
    • better TAM in incomplete avulsion implantation than complete
43
Q

Describe the technique for reimplanatation/revascularisation?

A
  • under microscope
  • lateral incision on ulnar aspect
  • arteries
    • thorough debridment of non viable tissue
    • thorough arterial debridment
    • repair using vein graft-significant damage
    • may need another step- down vein graft because of difficutly of matching sizes
    • may reroute arterial pedicle from adjacent digit
  • Veins
    • repair at least 2 veins
    • important factor in revascularization failure
  • ​Bone
    • ​If amputation at DIPJ , preform primary arthrodesis DIPJ
  • ​Skin
    • ​Preform FTSG or venous flap to prevent tight closire
44
Q

Describe the complications for replantation?

A
  • Cold Intolerance
  • Revascularization/replanatation failure
    • Sig factors is repair of <2 veins
    • Vascular damage to digital pulp
    • smoking and level of bione injury not been found to effect survival
  • Flexion Contracture
  • Malunion
  • revision surgery
  • revision amputations-> Hyperaesthesia