Compartment Syndrome of the Lower leg
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Vogt described the acute anterior compartment syndrome in 1943
compartment syndrome in all four anatomic compartments of the leg
Anatomy
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Taylor described 5 compartments with the 5th compartment being tibialis posterior as
it is encased all around by rigid structures
Source arteries and their venae comitantes travel adjacent to, but not within, these
rigid walls
Pathophysiology
 elevated compartment pressure causes muscle and nerve ischemia.
 Tissue perfusion is proportional to the difference between the capillary perfusion
pressure (CPP) and the interstitial fluid pressure (=venous pressure)
1. local blood flow = (PA – PV) / R
 Normal myocyte metabolism requires a 5-7 mm Hg oxygen tension, which can
readily be obtained with a CPP of 25 and an interstitial(compartmental) tissue
pressure of 4-6 mm Hg (4-21mmHg)
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When fluid is introduced into a fixed-volume compartment, tissue pressure increases
and venous pressure rises.
When interstitial pressure exceeds CPP, capillary collapse and muscle and tissue
ischemia occurs.
With myocyte necrosis, myofibrillar proteins decompose into osmotically active
particles that attract water from arterial blood -, a relatively small increase in
osmotically active particles in a closed compartment attracts sufficient fluid to cause a
further rise in intramuscular pressure.
compartmental pressures higher than 30 mm Hg in general require surgical
intervention.
Untreated, within 6-10 hours, muscle infarction, tissue necrosis, and nerve injury will
result
Muscle ischaemia lasting >4hours gives rise to myoglobinurea – which reaches its
maximum 3 hours after circulation is restored
Muscles can tolerate ischemia well for 4hours, by 6 hours outcome is uncertain and
after 8 hours, irreversible.
Peripheral nerves will conduct impulses for 1 hour following ischeamia, can survive 4
hours with only neuropraxic damage; after 8 hours damage is irreversible.
Mechanism of CS following vascular trauma may differ slightly because most cases
occur with reperfusion - related to the ischemic depletion of high-energy
phosphate forms and ischemic muscle injury.
The anterior compartment is particularly vulnerable to ischemia because it is housed
in a compartment with rigid walls across which vascular connections are sparse.
Taylor reports that the blood supply in the anterior compartment is anatomically most
vulnerable to ischaemia as it is the only compartment supplied by 1 vessel (anterior
tibial artery)
Aetiology
Internal pressure
1. trauma
i. 45% caused by tibial fractures – 6% of open fractures and 1.5% of
closed fractures
ii. 23% caused by soft tissue injury without fractures
2. vascular injury
3. crush/compression
4. iatrogenic fluid extravasation
External Pressure
1. prolonged incumbency
2. tight plaster
3. burns
4. poor surgical positioning
Classification
1. acute, - induced by trauma, prolonged ischaemia, severe exercise or tetany
2. chronic
a. usually exercise related
b. Often occurs bilaterally, and similar to claudication, the pain it causes
may be reproducible at a specific exercise distance or time interval
c. tend to subside within 1 hour of terminating the activity and are
minimal during normal daily activities but return when activity is
resumed.
d. anterior and lateral compartments of the lower leg are commonly
affected. The deep and posterior compartments are less commonly
involved.
e. Diagnostic criteria (1 or more of the following; 95% confidence level):
i. a resting pressure of greater than or equal to 15 mm Hg
ii. a 1-minute postexercise pressure of greater than or equal to 30
mm Hg
iii. 5-minute postexercise pressure of greater than or equal to 20
mm Hg
Clinical
 traditional 5 Ps (ie, pain, paraesthesia, pallor, pulselessness, poikilothermia) are not
clinically reliable and manifest only in the late stages of CS
 Important early signs:
1. Pain
o hallmark of muscle and nerve ischaemia is pain – persistent, progressive and
unrelieved by immobilization.
2. Passive stretch test
o best early clinical sign in the awake patient is severe pain with passive stretch
of involved muscles and crescendo pain out of proportion to the original
injury
3. Diminished sensation is the second most important finding
o in acute anterior lower leg CS, the first sign may be numbness between the
first two toes (superficial peroneal nerve). Decreased 2-point discrimination is
the most consistent early finding. Correlation has also been reported between
diminished vibration sense (256Hz) and increasing compartment pressure
4. Weakness/diminished muscle function
o Especially if progressive
5. Palpation for tenseness and tenderness
Investigations
 Blood – serum myoglobin and CK, UE, FBC, coags
 Urinalysis
 Xray
 MRI may show increased signal intensity in an entire compartment on T2-weighted
spin echo sequences.
 US alone is not useful in making the diagnosis of CS
Pressure Measurement
 If the diagnosis is clinically evident, it is not necessary to measure the compartment
pressures.
 Both needle techniques and catheter techniques require a bubble-free column of
saline, and the tip may become blocked by muscle and blood clot.
 Use 18-gauge needle and pressure transducer
 Direct pressure measurement kits are available
Infusion method
 Involves injecting saline into a compartment, pressure required to inject bubble of
saline is recorded
Slit catheter
 Slit catheter filled with saline and attached to transducer
Indications
 Most use a measured compartment pressure of >30 mm Hg as a cutoff for fasciotomy
 Others use the delta p pressure - diastolic pressure minus the intra-compartmental
pressure; if delta p is less than 30mmHg then fasciotomy.
 If CS is diagnosed late, fasciotomy is of little benefit. In fact, fasciotomy is
probably contraindicated after the third or fourth day. When performed late,
severe infection usually develops in the necrotic muscle.
Management
Non surgical
1. Fluid resuscitation especially in the presence of myoglobinurea
2. Place the affected limb(s) at the level of the heart. Elevation is contraindicated
because it decreases arterial flow and narrows the arterial venous pressure
gradient and thus worsens the ischemia.
3. Remove all circumferential dressings - Releasing one side of a plaster cast can
reduce compartment pressure by 30%, bivalving can produce an additional 35%
reduction, and cutting Webril may decrease compartmental pressure by 10-20%.
4. Mannitol may reduce compartment pressures and lessen reperfusion injury.
 shown to reduce the incidence of compartment syndrome after
revascularisation.
5. Hyperbaric treatment reported to be useful - promotes hyperoxic
vasoconstriction, which reduces swelling and edema and improves local blood
flow and oxygenation. It also increases tissue oxygen tensions and improves the
survival of marginally viable tissue.
Surgical
 The goal of decompression is restoration of muscle perfusion within 6 hour
 Treatment is compartment release with subsequent orthopedic reduction or fracture
stabilization and vascular repair, if needed.
 For lower leg - 4(5) compartment release with incisions:
1. single lateral incision
i. incision directly over fibula
ii. find anterior intermuscular septum to release anterior and lateral
compartments
iii. divide the origins of the soleus from the fibula and then, directly
behind the fibula, release the deep posterior compartment.
2. medial and lateral incisions
i. posterior compartment approached from medial
ii. lateral and anterior compartments from lateral
 For thigh –
1. lateral incision
i. able to release all three compartments
ii. to prevent muscle herniation – perform 2 parallel incisions along fascia
lata 4-5cm apart.
Compartment Syndrome of the Foot
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compartment syndromes can occur in the foot
mechanism of injury is severe local trauma, & assoc skeletal injury - may be minimal;
classic symptoms & signs are progressive pain, numbness in toes, and decreased
motion
tense tissue bulging may be the most reliable symptom;
compartmental pressures will be elevated;
note that compartment syndromes of the foot are associated with compartment
syndromes of the deep posterior compartment
Anatomy
 9 compartments of the foot can be placed into 4 groups;
1. Intrinsic Compartment:
o 4 intrinsic muscles between the 1st and 5th metatarsals;
2. Medial Compartment:
o abductor hallucis;
o flexor hallucis brevis;
3. Central Compartment: (Calcaneal Compartment)
o flexor digitorum brevis;
o quadratus plantae;
o adductor hallucis;
4. Lateral Compartment:
o flexor digiti minimi brevis;
o abductor digiti minimi;
Clinical Findings
 pain alone is not sufficient for diagnosis;
 increased pain on passive dorsiflexion of metatarsophalangeal joints is key finding
(indicating myoneural ischemia in intrinsic muscles);
 poor capillary refill and absent pulses are late findings.
 in the presence of massive swelling of the foot, which usually accompanies these
injuries, pulses are usually not palpable.
Surgical Treatment
 appropriate treatment for a suspected compartment syndrome of the foot is immediate
and complete fasciotomy;
 abductor hallucis longus, central, lateral, and interosseous compartments
must be released;
 effective decompression of all 4 compartments can be accomplished thru medial
longitudinal Henry approach, or thru 2 parallel dorsal incision along the lengths
of the second and fourth metatarsals;
1. medial approach:
- approach of choice;
- can be used to all 4 foot compartments;
- extends from a point below the medial malleolus (3 cm from the sole)
to proximal aspect of first metatarsal;
- once the neurovascular bundle has been retracted out of the way, the
fascia overlying the abduction hallucis and FDB is released; medial
intermuscular septum is opened longitudinally;
- the lateral plantar neurovascular bundle is found coursing over the
quadratus plantae (central compartment) as they course laterally;
- the remaining compartments (central, lateral, intrinsic) are entered thru
blunt dissection with a clamp
- lateral compartment is found by retracting the FDB out of the way;
2. dorsal approach:
- often the dorsal approach is not necessary unless there is concomitant
metatarsal or Lisfranc fractures;
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accomplished through 2 dorsal incisions centered just medial to the 2nd
metatarsal and just lateral to the 4th metatarsals (to maximize skin
bridge);
avoid injury to sensory nerves and extensor tendons;
superficial fascia is divided and interosseous are elevated off the
metatarsals to further decompress the compartments;
clamp is used to bluntly dissect thru the central, medial, and lateral
compartments;
separate medial incision may be needed to release the abductor;
fasciotomy incisions may be used for fracture fixation;