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Plastic Surgery - HAND > Chapter 43 - Replantation > Flashcards

Chapter 43 - Replantation Flashcards

1
Q

What is the goal of digital replantation?

A

Equivalent or improved function when compared to revision amputation and prosthesis

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2
Q

What are the current indications for digital replantation?

A

Thumb, multiple digits, single digits distal to FDS insertion, hand at wrist or forearm (sharp), any amputation in a child

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3
Q

What is the appropriate workup for a patient with amputated digit?

A

ATLS, Do not complete amputation until fully evaluated in OR, wrap part in moist gauze and in plastic bag, place plastic bag in ice. IV antibiotics, Tetanus. Xrays. Consent for possible nerve/vein graft and amp as well as replant.

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4
Q

What is the order for replantation steps?

A

Bone, Extensors, Flexors, Arteries, Nerves, Veins

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5
Q

What is the order for multiple digit replantations?

A

Structure by structure (all bones, then all tendons, then all arteries, then all nerves, then veins)

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6
Q

What are the potential advantages in skeletal shortening in digital replantations?

A

May enable more secure bone fixation, may minimize need for vessel or nerve grafting

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7
Q

What are the options for skeletal stabilization in digital replantation?

A

K wires, 90-90 wiring, miniplates and screws, intramedullary bone pegs

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8
Q

What are the functional deficits associated with ray amputations of the index finger?

A

Loss of power grip and key pinch

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9
Q

What is the lumbrical plus deformity?

A

FDP tendon and lumbrical muscle migrate proximally after division of the tendon in trauma. With flexion , tension is exerted on the lumbrical via the radial lateral band causing paradoxical extension of the PIP during flexion of the MP joint

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10
Q

What is the treatment for lumbrical plus deformity?

A

Division of the lumbrical insertion

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11
Q

What is the most common cause of digital replantation failure?

A

Arterial insufficiency

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12
Q

What is the treatment of arterial insufficiency after digital replantation?

A
  1. If any concern about arterial insufficiency, return to OR
  2. Loosen dressings
  3. Heparin
  4. Antivasospastic meds (thorazine)
  5. Sympathetic blocks
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13
Q

What is the treatment for venous congestion after digital replantation?

A
  1. Removal of dressings
  2. Leeches
  3. Heparin
  4. Nail bed bleeding with heparin-soaked sponges
  5. Revision of venous anastamosis
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14
Q

Which tissue is most sensitive to warm ischemia

A

Skeletal muscle

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15
Q

What is the maximum cold ischemia time reported for digital ischemia?

A

30-40 hours

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16
Q

When should prophylactic fasciotomies be performed in upper extremity replantation?

A

With any replantation proximal to the wrist (because of increased skeletal muscle present)

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17
Q

What is the quadriga effect?

A

Weakness in flexion of the fingers secondary to excess pull of one FDP tendon of the amputated finger

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18
Q

What is the maximum nerve gap for use of a neural tube (PGA)?

A

2.5cm

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19
Q

What nerves are available for donor grafting?

A

Posterior interosseous, sural, superficial radial, superficial peroneal

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20
Q

What is the treatment of choice for a tip amputation through the nail bed without bone exposed?

A

Local dressing changes (healing by secondary intention)

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21
Q

What is a good option for failed thumb replantation at the MCP level?

A

Revision amputation followed by toe to thumb transfer at a later date

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22
Q

What donor vessel is the toe-to-thumb transfer based on?

A

First dorsal metatarsal artery from the dorsalis pedis artery or plantar digital artery from the lateral plantar artery

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23
Q

What is a good option for a thumb-tip amputation with exposed bone?

A

Moberg flap

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24
Q

How much advancement can be obtained from a Moberg flap?

A

1.5cm

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25
Q

What are contraindications to digital replantation?

A

Severe concomitent injuries, severely crushed or mangled part, multilevel amputations, significant comorbidities (relative), prolonged warm ischemia time, Mentally instable/self-mutiliation (relative), single finger proximal to FDS insertion

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26
Q

How many arteries and veins are needed for a digital replantation?

A

One artery and one vein (two is preferred if possible)

27
Q

Is an artery-only digital replantation possible?

A

Yes. Leeching and/or bleeding of the nail bed can be used to relieve venous congestion

28
Q

How many places can you find a digital vein?

A

Two. Dorsal and volar.

29
Q

What is the concern in avulsion amputation vs guillotine amputation?

A

Zone of injury is much greater in avulsion injuries

30
Q

What is the red stripe sign?

A

A red streak along an artery indicating severe intimal injury along the length of the vessel

31
Q

What is the best method for treating the zone of injury of an artery or vein in the case of crush or avulsion injuries?

A

Resection of the compromised vessel and vein grafting

32
Q

Where can veins be found on the hand dorsum?

A

Proximal to each webspace

33
Q

What vascular pattern exists in a finger that was crushed and has the appearance of venous congestion and low capillary refill?

A

Loss of proper digital artery inflow, intact venous flow

34
Q

Eight months post digital replantation, what operation would you offer the patient with minimal active or passive ROM?

A

Extensor tenolysis and open capsulotomy

35
Q

What operation would you offer s/p digital replantation with minimal active ROM but good passive ROM?

A

Flexor tenolysis

36
Q

What is the greatest danger in digital reoperation after replantation?

A

Injury to the neurovascular bundle embedded in the scar

37
Q

What is fluorimetry?

A

a method of monitoring tissue perfusion by injecting fluorescein dye intravenously and using a fluorometer to quantitatively measure rise and fall of fluorescein in tissue

38
Q

What if there is a two to threefold rise but no fall in the number on fluorimetry?

A

Signs of venous congestion

39
Q

What if the absolute number (on fluorimetry) is very low and remains low, but the digit clinically looks viable?

A

Thick skin or heavily contaminated skin can alter the numbers

40
Q

When is the highest likelihood of a thrombotic event at the microanastomosis?

A

Within 24-48 hours

41
Q

At the microanatomosis, what is the most prominent cell layer on day 3?

A

Platelets

42
Q

At the microanatomosis, what is the most prominent cell layer on day 4-14?

A

Pseudointima

43
Q

At the microanatomosis, what is the most prominent cell layer on days 14+?

A

Intima

44
Q

One year status post replantation at the PIPJ level with severe arthritis or fusion at the PIPJ. What surgery can you offer the patient?

A

PIP Joint arthroplasty

45
Q

Which Urbanik class of ring avulsion is considered a relative contraindication to replantation?

A

III - complete degloving or complete amputation

46
Q

What type of flap can be used if there is a soft-tissue defect in a Type II ring avulsion injury?

A

Venous flow through flap

47
Q

What is the average two point discrimination of a replanted thumb

A

9-11mm

48
Q

What is the average two point discrimination of a replanted digit?

A

8-15mm - depending on sharp vs avulsion

49
Q

What is the “no reflow phenomenon”?

A

Inability to maintain perfusion to he replanted tissue despite restoration of blood flow through a technically acceptable anastomosis. Thought to be the result of inschemia-induced endothelial injury

50
Q

What is a common long-term sequelae of digit replantation?

A

Cold intolerance. This occurs commonly in the adult population but can also affect peds

51
Q

How much time should you tell a patient they will have to wait for cold intolerance symptoms to resolve?

A

2 years, maybe never

52
Q

What is the scientific name for medical leeches?

A

Hirudo medicinalis

53
Q

Action of Hirudin?

A

Binds activated thrombin (1:1)
Inhibits conversion of fibrinogen to fibrin
Blocks activation of Factors V, VIII, XI, and vWF.
Decreases activation of tPA, protein C and plasmin
Prolongs thrombin-dependent coagulation tests (PTT, TT, ACT, ECT)
There is no direct effect on platelets or endothelial cells
Can monitor by thrombin time and PTT

54
Q

Excretion of hirudin?

A

Renal

55
Q

Organisms to cover while patient is on leech therapy?

A

Aeromonas hydrophilia - enteric organism that can cause severe soft tissue infection.

56
Q

What medications to use with leech therapy?

A

Third generation cephalosporin (Cefizox) or aminoglycosides (tobramycin, gentamicin) in adults. Bactrim or cipro in peds.

57
Q

What is the mechanism of heparin?

A

Action primarily via activation of serum antithrombin III and lowering blood viscosity, increases AT III activity

58
Q

Mechanism of dextran

A

Polysaccharide - molecular weight 40,000 and 70,000
Decreases platelet aggregation by imparting a negative charge on the platelets, inactivating vWF
Modifying the structure of fibrin
Altering rheologic property of blood

59
Q

Possible complications of dextran

A

Possible complications: antigenic test of <5ml must be given before full dose
Renal failure - volume expansion
Noncardiogenic pulmonary edema

60
Q

What is the mechanism of aspirin?

A

Acetylates cyclooxygenase enzyme
Decreases arachnodonic acid, thromboxane, and prostacycline
Decreases platelet aggregation and vasoconstriction

61
Q

What is the mechanism of Thorazine?

A

Potent vasodilator

62
Q

What is the mechanism of papaverine?

A

Salt of opium alkaloid. Smooth muscle relaxant especially with cerebral and peripheral ischemia associated with arterial spasm

63
Q

What is the mechanism of lidocaine?

A

Potent local vasodilitation. Commonly used at 2% dilution

64
Q

What is the definitive role of anticoagulation in microsurgery?

A

Controversial. Not enough RCT. Common uses: high-dose heparin irrigation during microanastomosis. IV heparin after a thrombotic event with anastomotic revision

Plastic Surgery - HAND (16 decks)

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