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
2
Q
how is the tibia connected to the fibula?
A
- proximally, tibiofibular joint
- distally, tibiofibular syndesmosis
- intermediate: interosseous membrane
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
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
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
- gastrocnemius - plantarflexion of foot and flexion of knee
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
- tibialis posterior - plantar flexion
- 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%
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
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
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
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)
- vascular: palpable DP or PT pulse, colour, CR temperature, turgor of foot, bedside doppler
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
13
Q
what are the 3 most common isolates in lower extremity osteomyelitis?
A
1) Staph aureus
2) Pseudomonas
3) Anaerobes
14
Q
what are the major advances in lower extremity reconstruction through history?
A
- Immobilization
- Antibiotics
- Debridement and delayed closure (WWII)
- Vascular repair (vs. ligation)
- Soft tissue coverage with regional flaps then microsurgery
- Management of bone gaps with vascularized bone or distraction osteogenesis
- VAC
- Perforator flaps
15
Q
Describe your thought process when making a reconstructive plan for lower extremity trauma
A
- Is there a vascular injury?
- Quick access to high quality angio vs. on-table angiography
- If vascular and skeletal injury, consider temporary vascular shunts if completely devascularized lower extremity and warm ischemia time approaching 4-6 hours
- Skeletal stabilization - options
- Casting, traction - uncommon, temporizing, closed
- 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
- Internal fixation
- intramedullary rod - requires immediate ST coverage; endo-osteal stripping; minimally comminuted and minimal bone loss; allows for early ambulation
- plate - requires immediate ST coverage; significant foreign body; significant periosteal/soft-tissue stripping
- Definitive vascular repairs
- 4-compartment Fasciotomy for every case of vascular repair; for most open fracture or crush injury patients
- Debridement of non-viable tissue and debris
- Vital structures NOT exposed, incomplete debridement of further delineation of zone of injury expected
- plan for second/third debridement
- Vital structures ARE exposed
- complete debridbement of all evident and anticipated non-viable tissue
- immediate coverage
- complete debridbement of all evident and anticipated non-viable tissue
- Definitive soft tissue coverage - principle should be generally within 1 week of injury; should be immediately at placement of internal hardware
- When should VAC be considered
- within first week prior to definitive coverage
- may be more useful for small wounds to help avoid operation for soft-tissue cover
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
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
