Lower extremity reconstruction Flashcards

1
Q

WHAT ARE SOME UNIQUE FEATURES OF LOWER EXTREMITY RECONSTRUCTION?

A
  • Full body weight is transmitted through the legs and ankle:
    • must withstand stress and gravitational forces
    • is sensate, padded, and stable
  • Greater incidence of vascular disease
    • atherosclerosis
    • Venous stasis, edema, thrombosis 2’ high hydrostatic pressure imposed on LE
  • Longer time (distance) for nerve regeneration
  • Multi-disciplinary - orthopedics, vascular surgery, plastic surgery + allied health
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2
Q

how is the tibia connected to the fibula?

A
  • proximally, tibiofibular joint
  • distally, tibiofibular syndesmosis
  • intermediate: interosseous membrane
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3
Q

Describe the anatomy of the anterior compartment of lower leg

A
  • 4 muscles: tibialis anterior, extensor hallucus longus, extensor digitorum longus, peroneus tertius
    • actions: all dorsiflex the foot. TA also inverts whereas PT everts. EHL extends great toe and EDL extends other toes
    • innervation: deep peroneal n
    • arterial supply: muscular branches from anterior tibial artery.
      • TA: type IV. EHL and EDL
  • Artery travels:
    • originates from politeal artery at it’s lower border
    • crosses btwn 2 heads of TP to enter anterior compartment
    • proximal 1/3 travels on IO membrane btwn TA and EHL
    • middle 1/3 travels on IO membrane btwn TA and EDL
    • lower 1/3 travels on anterior surface of tibia, btwn EHL and 2nd toe EDL; runs under extensor retinaculum to become superficial as dorsalis pedis artery
  • Nerve travels:
    • originates as common peroneal n
    • bifurcates around head of fibula
    • runs on fibula for short distance (3-4cm) before crossing IM septum to enter anterior compartment (from lateral compartment)
    • runs under EHL on anterior surface of IO membrane
    • initially is lateral to anterior tibial artery, then as approaches ankle it runs superficial to medial side
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4
Q

describe the anatomy of the lateral compartment of the lower leg

A
  • muscles include peroneus longus and peroneus brevis
    • action: both evert and plantar flex the foot
    • innervation: superficial peroneal n
    • arterial supply: PL - muscular branches from ATA and peroneal a; PB just muscular branches from peroneal a
    • the superficial peroneal nerve travels between PL and PB
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5
Q

describe the contents of the superficial posterior compartment of lower leg

A
  • muscles
    • gastrocnemius - plantarflexion of foot and flexion of knee
      • tibial nerve
      • medial and lateral sural arteries (from popliteal, type I)
    • soleus - plantarflexion foot
      • tibial nerve
      • muscular branches from posterior tibial and peroneal, and sural arteries
    • plantaris - weak plantarflexion; excellent for tendon graft
      • tibial nerve
      • sural arteries (from politeal)
    • popliteus - flexes knee and rotates tibia
      • tibial nerve
      • genicular brancehs of popliteal artery
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6
Q

describe the contents of the deep posteiror compartment of the lower leg

A
  • muscles:
    • tibialis posterior - plantar flexion
      • tibial nerve
      • muscle branches of peroneal a
    • flexor hallucus longus - great toe flexion, plantar flexion
      • tibial nerve
      • muscular branches of peroneal a
    • flexor digitorum longus - 2nd - 5th toe flexion, plantar flexion
      • tibial nerve
      • muscular branches of posterior tibial artery
  • course of posterior tibial artery - travels w tibial nerve
    • deep to deep investing fascia/solus
    • initially on tibialis posterior, then on FDL,
    • lower 1/3 becomes more superficial, runs medial to tendo-calcaneous, nearly on tibia, then crosses joint
  • the tibial nerve is intially medial, then runs deep and lateral to artery
  • at medial malleolus - Tom, Dick, And Now Harry
    • Tib Post
    • Flexor Digitorum longus
    • Artery - posterior tib
    • Nerve - tibial
    • Flexor Hallucus longus
      *
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7
Q

what is the risk of compartment syndrome wiht open tibial fracture?

A

6-9%

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8
Q

What is the Gustillo Classification? Describe it.

Why is it used?

A
  • Gustillo classification was originally intended to classify open tibial fractures, although now it has extended in context to describe open fractures of long bones in other parts of the body
  • it’s original purpose was to help describe treatment and salvage
  • Grade 1: simple fracture, skin clean, laceration < 1cm
  • Grade 2: open fracture, wound > 1cm, without extensive damage
  • Grade 3:
    • higher velocity injury, segmental fracture, comminution, EXTENSIVE SOFT TISSUE DAMAGE: including, devitalization or contamination,
    • 3A: extensive soft tissue injury, but sufficient viable tissue for bone coverage
    • 3B: with periosteal stripping and bone exposure, insufficient for bone coverage
    • 3C: any open tibial fracture with arterial injury requiring repair
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9
Q

What are the limitations of the Gustillo classification?

A
  • does not sufficiently quantify the extent of soft tissue or bone damage
  • does not differentiate between ambiguity of leg wiht arterial injury while maintaining sengle vessel run-off
  • does not accurately classify patients to salvage vs. amputation
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10
Q

Describe history for lower extremity traumatic wound

A
  • after ATLS

HPI

  • ID: age, occupation, hobbies
  • other associated injuries, their treatments, prognosis
  • mechanism: high vs. low energy, twist/rotational forces vs compression forces vs tangential forces
  • initial ability to ambulate, noted changes to gait, sensation etc
  • initial first aid provided

PMHx/SOC Hx/MEDS/ALL/smoking status

  • all especially DM, CAD, PVD, history of VTE
  • baseline gait and weight bearing, use of assistant devices

Any goals or expectations of management

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11
Q

Describe comprehensive examinations for mangled lower extremity

A

ATLS first

  • Assessment for limb viability: examine wound, vascular, soft tissue, skeletal, nerve injuries
    • vascular: palpable DP or PT pulse, colour, CR temperature, turgor of foot, bedside doppler
      • for a stable patient with gustillo grade III (at least IIIB +) angiogram for lower extremity vascular assessment
    • skeletal injury: visible bone in wound, mandatory XR evaluation: open/closed; simple/segmental/comminuted; displacement/angulation
      • also direct visualization (typically in OR at 1st wash) for extent of periosteal stripping, viability of bone segments
    • soft tissue: status and viability of skin, SC tissue, muscle, periosteum
      • avulsion, crush, viability, etc
      • initial assessment in ED; best assessed in OR during debridement
    • neurologic
      • motor exam: anterior compartment muscles (deep peroneal); lateral compartment (superficial peroneal); deep compartments (tibial)
      • sensory exam: dorsal foot (sup peroneal), dorstal 1st web (deep peroneal), plantar surface (medially and laterally, tibial nerve to medial and lateral plantar nerves); lateral malleolus (sural nerve)
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12
Q

what is the overarching goal of lower extremity reconstruction?

A
  • To reconstruct a limb that is more functional than if it were to be amputated
  • If limb-salvage is not feasible, the goal becomes to preserve sufficient length for a below-knee prosthesis
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13
Q

what are the 3 most common isolates in lower extremity osteomyelitis?

A

1) Staph aureus
2) Pseudomonas
3) Anaerobes

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14
Q

what are the major advances in lower extremity reconstruction through history?

A
  1. Immobilization
  2. Antibiotics
  3. Debridement and delayed closure (WWII)
  4. Vascular repair (vs. ligation)
  5. Soft tissue coverage with regional flaps then microsurgery
  6. Management of bone gaps with vascularized bone or distraction osteogenesis
  7. VAC
  8. Perforator flaps
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15
Q

Describe your thought process when making a reconstructive plan for lower extremity trauma

A
  1. Is there a vascular injury?
  2. Quick access to high quality angio vs. on-table angiography
  3. If vascular and skeletal injury, consider temporary vascular shunts if completely devascularized lower extremity and warm ischemia time approaching 4-6 hours
  4. Skeletal stabilization - options
    1. Casting, traction - uncommon, temporizing, closed
    2. External fixation - preferred method for initial presentation; no additional periosteal/endosteal stripping or soft-tissue disruption; allows access to wound for additional debridements and eventual coverage
    3. Internal fixation
      1. intramedullary rod - requires immediate ST coverage; endo-osteal stripping; minimally comminuted and minimal bone loss; allows for early ambulation
      2. plate - requires immediate ST coverage; significant foreign body; significant periosteal/soft-tissue stripping
  5. Definitive vascular repairs
  6. 4-compartment Fasciotomy for every case of vascular repair; for most open fracture or crush injury patients
  7. Debridement of non-viable tissue and debris
  8. Vital structures NOT exposed, incomplete debridement of further delineation of zone of injury expected
    1. plan for second/third debridement
  9. Vital structures ARE exposed
    1. complete debridbement of all evident and anticipated non-viable tissue
      1. immediate coverage
  10. Definitive soft tissue coverage - principle should be generally within 1 week of injury; should be immediately at placement of internal hardware
  11. When should VAC be considered
    1. within first week prior to definitive coverage
    2. may be more useful for small wounds to help avoid operation for soft-tissue cover
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16
Q

when do you consider getting a CT angiogram during lower extremity trauma

A
  • massive / severely mangled injuries
  • identified or suspected ischemic injury
  • injuries that will require soft tissue reconstruction
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17
Q

Discuss considerations of nerve injury for lower extremity injury

A
  • prognosis for re-innervation is poor
    • long distance from injury to motor end plate
    • large zone of injury necessitating long nerve grafts
    • motor end plate atrophy
  • peroneal nerve injury - in general loss of dorsiflexion (foot drop) & sensation on dorsum
    • sensory loss tolerated well
    • motor loss managed w/ splinting or tendon transfers
  • tibial nerve injury - in general loss of plantar flexion & sensation on plantar
    • loss of plantar flexion significantly impairs ambulation (loss of push-off), would consider joint fusion
    • loss of plantar sension impairs gait, evolve to charcot arthropathy, prone to occult injury - similar to diabetic foot neuropathy
    • reconstruction with tibial nerve injury is guarded but not contra-indicated
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18
Q

Discuss considerations in management of bone gaps in lower extremity trauma

A
  1. Available methods
    1. Non-vascularized bone graft
      1. Small gaps < “few” (?4) cm when there is a well-vascularized and stable bed
    2. Distraction osteogenesis (Iliazarov technique)
      1. Gaps 4-8cm
      2. Obliterate gap w/ graft, then distract after union at fraccture site achieved
      3. Vs. fill gap w/ non-vascularized cancellous graft, then distract proximal or distal segment to the gap
    3. Vascularized bone graft
      1. Gaps > 8 < 24cm
      2. Best choice is fibula for this indication
        1. In theory ipsilateral pedicle may be available; otherwise contralateral free
        2. length of fibula - 12cm is available for reconstruction; could split & fold in 1/2
  2. Timing of repair
    1. Immediate bone gap repair with definitive soft tissue coverage
    2. Wound control, definitive soft tissue coverage with placement of antibiotic beads, wound bed allowed to mature, delayed bone gap management
      1. Preferred approach
19
Q

for mangled lower extremity injuries, what is one factor that promotes use of free tissue transfer compared to use of local fasciocutaneous or muscle flaps?

A
  • Local flaps remain in zone of injury
20
Q

what are the principles of treatment once osteomyelitis has been established after lower extremity trauma?

A
  • debridement of all devitalized soft tissue and bone
  • reconstruction of defect with healthy, well vascularized tissue
  • placement of antibiotic beads
  • external fixation
  • systemic antibiotics
  • delayed definitive management of bone gap
21
Q

Why do we emphasize preservation of length even when we are going to amputate during lower extremity truama?

A
  • BKA has elevated energy expenditure and oxygen consumption compared to non-amputee, but AKA is significantly greater than BKA
  • BKA can walk longer distances
    • AKA are less likely walk at all, may require motorized transport/chair
22
Q

what is the ideal length of preserved tibia for BKA?

A
  • > 6cm below the tibial tubercle
23
Q

List the muscles in each layer of the foot

A
  • Dorsum: EDB
  • Plantar:
    • 1st level: AbdH, FDB, AbdDMB
    • 2nd level: quatratus plantaris, lumbricals
    • 3rd level: FHB, AddH, FDMB
    • 4th level: plantar and dorsal interosseous
24
Q

what branches does the tibial nerve give to the foot?

A
  • medical calcaneal (sensory only)
  • medial and lateral plantar (sensory and motor)
25
Q

What are the contents and boundaries of the femoral triangle?

A
  • boundaries:
    • lateral - sartorius
    • medial - adductor longus
    • superior - inguinal ligament
    • floor: pectineus, iliopsoas, other adductors (brevis, magnus)
  • contents
    • Within femoral sheath, from medial to lateral:
    • Femoral vein, Femoral artery, Lymph nodes (of Cloquet)
    • Lateral to femoral sheath is greater saphenous vein (draining into femoral vein)
    • Femoral nerve (most lateral)
26
Q

What is Hunter’s canal? How is it related to femoral triangle? What enters/exits?

A
  • Hunter’s canal is adductor hiatus / canal through adductor magnus
  • Allows for femoral artery to move from anterior to posterior (otherwise would have significant traction w/ knee bending)
  • Sheath of canal is inferior extension of femoral sheath (from wihtin femoral triangle)
  • Permits the femoral artery (SFA), femoral vein and saphenous nerve
27
Q

what are the specific reconstructive goals for lower extremity reconstruction?

A
  1. debride all devitalized tissue and debris & obtain healthy wound bed
  2. restore vascular integrity
  3. restore skeletal stability
  4. provide stable, durable, well-vascularized soft tissue coverage of bone, nerve, vessels, tendons, internal hardware
  5. obliterate dead space and provide contour over 3D anatomy
  6. provide a functional lower extremity for bipedal ambulation
  7. maintain acceptable aesthetics
  8. minimize donor site morbidity
28
Q

How do you classify lower extremity defects?

A
  1. By etiology
    1. Congenital
    2. Acquired (majority)
      1. Trauma - subclassify by mechanism: low/high velocity; compression/lateral/torsion/crush; open/closed
      2. Tumour - benign, malignant, metastatic; tissue involved by tumour
      3. Infection - soft tissue, osteomyelitis
      4. Ischemic - vascular insufficiency (arterial, venous); compartment syndrome
      5. Iatrogenic - surgical (dehiscence, exposed vital structures), radiation
      6. Endocrine - diabetic foot or lower extremity wonds
    3. By sub-site on extremity
    4. By tissue involved
29
Q

What are the phases of open fracture?

A
  • acute - inflamed - day 1-5
  • subacute - colonized +/- infected - day 5 to week 6
  • chronic - infection of scar, sequestrum - > 6 wks
30
Q

what are some specific systemic coplications of open tibial / lower extremity fracture

A
  • hemorrhage
  • fat embolism
  • venous thromboembolism
  • rhabdomyelitis
  • compartment syndrome
31
Q

List absolute and relative contraindications to limb salvage in mangled lower extremity trauma

A
  • Absolute
    • warm ischemia > 6 hrs
    • gustillo 3C + severe life threatening injuries
    • significant morbidity or other ongoing severe life threatening injury/polytrauma
    • multi-level injury
    • segmental tibial loss > 8cm
  • Relative
    • transection tibial nerve in adult
    • severe ipsilateral foot trauma
    • anticipated protracted (>1yr) course of soft tissue and bone management
32
Q

What factors do you consider when choosing and planning for the reconstruction?

A
  1. Wound
    1. size, site, tissue components
    2. adjacent planned/previous infection or radiation
    3. zone of injury
    4. foreign body / implant planned/present
    5. associated neurovascular injury
  2. Host factors - comorbidities
  3. Functional outcome
  4. Aesthetic outcome
  5. Planned recipient vessel and required pedicle length
  6. Anticipated future 2’ary procedures
33
Q

What factors influence your decision to choose a fasciocutaneous vs. muscle free flap in lower extremity reconstruction?

A
  • Muscle
    • dead space
    • 3D contour
    • more bulk (perhaps)
  • Fasciocutaneous
    • anticipated 2ary procedures
    • avoidance of skin graft / aesthetic outcome
    • less donor site morbidity
    • cutaneous sensation
34
Q

What are options and considerations for coverage of groin wounds?

A
  • Considerations:
    • need to determine which vessels are available or are not available based on regional anatomy, vascular (bypass) grafts, occluded/ligated vessels
  • Options
    • free tissue transfer rarely required
    • small wound: sartorius myoplasty (transpose w/ or w/o division of 1-2 (3) perforators - note periosteal origin counts as 1)
    • ipsilateral femoral vessels intact:
      • muscle (+/- skin or STSG): TFL, VL, RF, gracilis
      • FC: ALT, groin (SCIA)
    • ipsilateral femoral vessels absent, ispilateral external iliac intact
      • muscle (+/- skin or STSG): rectus abdominus/VRAM
      • FC: Ruben’s flap (w/ cuff of EO/IO/TA)
    • ipsilateral femoral and external iliac unavailable: contralateral VRAM (tram) vs free tissue transfer
35
Q

What are options for thigh reconstruction

A
  • depends on site (medial, lateral, anterior, posterior) and whether tere are any exposed vital structures
  • usually can use local tissue / muscle
    • TFL, ALT/VL, rectus femoris, gracilis, posteiror thigh flap, biceps/hamstrings
  • regional tissue/muscle
    • rectus abdominus/VRAM
36
Q

what are options and considerations for segmental femur defects?

A
  • > 12cm
    • free fibula - can be double-barrel or wihtin an allograft
  • 6-12cm
    • free fibula > iliac crest (has a natural curvature, significant donor morbidity)
  • < 6cm
    • free fibula > iliac crest > scapula
37
Q

What are options for coverage of the knee?

A
  • Medial gastroc
  • Lateral gastroc
  • proximally based soleus
  • free tissue transfer
  • (theoretically reverse ALT on anastomosis w/ superior genicular, never seen, don’t say)
38
Q

What are options for coverage of proximal 1/3 of lower leg?

What is #1 preference?

A

Local muscle (w STSG)

  • Medial gastroc - #1 choice
  • Lateral gastroc
  • Proximal (hemi) soleus
  • bipedicle tibialis anterior (small defect of tibia)

Local fasciocutaneous

  • saphenous flap
  • antegrade sural artery flap
  • posterior calf flap (descending cutaneous flap off branch of poplital a)
39
Q

What are options for coverage of middle 1/3 of lower leg defects? What is your #1 choice?

A

Muscle (w STSG)

  • proximally based hemi-soleus #1 option
  • medial > lateral gastroc
  • bipedicle tibialis anterior (small central tibial defect, partial harvest)
  • FHL (often taken w soleus to supplement that flap)
  • EDL or EHL (small defects, significant morbidity)

Fasciocutaneous

  • Ponten flap
  • propellor flap
40
Q

List reconstructive options for distal 1/3 leg (not ankle, foot)

A
  • generally or historically thought to require free tissue transfer, due to lack of reliable local options
  • for larger defects with significant exposed vital structures (vessels, nerves, bones, internal hardware) choose free tissue transfer
    • options
      • mid-sized defect, FC options: lateral arm, radial forearm, parascapular (scapular)
      • mid-sized defect, muscule options: gracilis
      • large-sized defect, FC options: ALT
      • large-sized defect, muscle options: LD, rectus abdominus
  • local options include, but be sure vessel intact and not significantly in ZOI:
    • PTA intact: PTA perforator flap, medial plantar artery flap
    • ATA intact: dorsalis pedis flap, EDB flap
    • PA intact: lateral supramalleolar flap, reverse sural flap (posterior defects)
    • PA & PTA intact: reverse hemi-soleus, lateral supramalleolar flap
41
Q

list local reconstructive options for medial and lateral malleoli

A
  • medial malleolus
    • ATA intact: dorsalis pedis / 1st DMTA +/- EDB, AbdH
    • PTA intact: PT perforator, medial plantar artery flap
    • PA intact: reverse sural
    • PA & PTA: reverse hemi(medial) soleus
  • lateral malleolus
    • ATA intact: dorsalis pedis / 1st DMTA +/- EDB
    • PTA intact: PT perforator
    • PA intact: reverse sural flap, lateral supramalleolar flap, peroneus brevis flap
    • PA & PTA: reverse hemi (lateral) soleus
42
Q

what are local options for heel reconstruction?

A
  • PTA: medial plantar artery flap (best option); can include FDB and medial calcaneal n
    • also lateral calcaneal artery flap + sural n.
  • PA: reverse sural artery flap (also good option) + sural n.
43
Q

What are considerations for recipient vessel for free tissue transfer in distal 1/3 and foot free flaps?

A
  • pre-operative angiogram to determine # / patency of vessels feeding the foot
    • if 1 or 2 vessel foot consider End-to-Side
  • if distal: choose PTA as 1st choice because calibre, superficial but protected location behind medial malleolus
    • ATA prone to kinking or compression w ankle movement when chosen distally
  • more proximally, outside ZOI, choose vessel that is closest to desired position of inset
  • know to find ATA ~ 1cm lateral to tibial crest, between TA and EHL proximally, and between EHL and EDL tendons @ ankle
  • know to find PTA in superficial part of deep posterior compartment proximally and distally until ankle (on PT muscle, then on FHL, then essentially on posteromedial tibia ); at ankle between FDL and tibial nerve/FHL
  • know that peroneal artery travels deep to fibula, pierces interosseous membrane ~ 5cm proximal to lateral malleolus
44
Q
A