Popliteal Artery Entrapment Syndrome

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Popliteal Artery Entrapment Syndrome
Peter OLeary Med IV
11th April 2006
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Aims

• Background of PAES
• Review anatomy of popliteal fossa
• Classify PAES
• Look at a case
• PC
• Exam
• Investigations
• Differential Dx
• Surgical Treatment
• Outcome

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Introduction

• Popliteal Artery Entrapment Syndrome (PAES)
• Popliteal entrapment was first described by a
  Scottish medical student, T. P. Anderson Stuart,
  in 1879
  
• Crush syndrome resulting from compression of the
  popliteal artery and impairment of its blood flow
  by structures of the popliteal space
  
• Non atheromatous cause of acute limb ischaemia
• Early diagnosis is important
• Very disabling

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Epidemiology

• 3-5 with anatomic predisposition (in pm exams of
  patients with symptomatic vasc disease)
  
• Males 81 Females
• Precise incidence rate is unknown (400 cases in
  literature)
  
• 2 types Congenital form/functional form
• Young people (80 personnel
  
• 25 bilateral

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?Tibial nerve
Adductor hiatus ?
Popliteal Artery ?
?Popliteal Vein

• Popliteal Artery
• Popliteal Vein
• Tibial Nerve
• Gastrocnemius Lat and Med
• Adductor hiatus

Lateral head of gastrocnemius
Medial Head of gastrocnemius
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Classification Type I

• Popliteal artery passes medial to and under a
  normal medial gastrocnemius head
  
• The vein remains in its normal position  

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Type II

• Medial head of the gastroc inserts more lateral
  than normal
  
• Artery descends in a straighter path around the
  medial margin of the muscle

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Type III

• Artery is compressed by a slip of the medial head
  arising more laterally than normal
  
• Artery passes through the body of the medial head
  in a relatively straight path

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Type IV

• Popliteal artery passes deep to the popliteus
  muscle or a band, with or without associated
  gastroc abnormality
  
• Reflects a persistence of a more primitive
  embryological vascular pattern of the leg

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Type VI functional

• Extrinsic compression of the popliteal artery
  without identification of anatomical alterations
  
  
• Hypertrophy of the gastrocnemius muscle

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Presenting Complaint

• 21 yo male
• Sharp pain in right and left calf and great toe
• Began 2 years ago and was becoming progressively
  more debilitating
  
• Pain was exacerbated by walking, not running
• Alleviated with rest
• Feet became cold and pale and he experienced
  numbness in the digits
  
• Toe and calf pain became severe if he stood for
  10 or more minutes

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Examination

• Unremarkable except
• Active Plantar flexion and passive dorsiflexion
  of the foot caused diminished dorsalis pedis and
  post tibial pulses
  
• Patient also had a pigeon toed walking gait
  foot turned inwards

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6 Ps Acute limb ischaemia

• Pulselessness
• Pain
• Pallor
• Poikilothermy (cold)
• Paresthesia
• Paralysis

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Investigations

• Investigations used to diagnose popliteal artery
  entrapment and to grade the severity of
  circulatory insufficiency and arterial damage
  
• Duplex doppler ultrasound screening exam
• Digital Subtraction Angiography (Gold Standard)
• CT scan

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Duplex Doppler ultrasound

• Knee in normal position and doppler shows no
  abnormality
  
• Plantar extension of foot and doppler reveals
  highly phasic, staccato waveforms, which suggest
  high-grade distal arterial stenosis
  
• Peak systolic and end-diastolic velocities can be
  measured

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Ankle-Brachial Index (ABI)
.

• Ratio of the higher systolic blood pressures
  between the dorsalis pedis and the posterior
  tibial artery to the higher of the systolic blood
  pressures in the two brachial arteries
• ABI values relate to severity of PAD

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CT scan

• Submaximal calf muscle contraction demonstrates
  accessory head of the gastrocnemius muscle (white
  arrow) compressing small-caliber right popliteal
  artery (black arrow)
• In comparison with the opposite normal-caliber
  left popliteal artery (arrow)
  

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Intra-arterial Digital Subtraction Angiography

• Images are acquired in digital format
• Blood vessels can be shown in a
  near-instantaneous film
  
• Right transfemoral digital subtraction angiogram
  shows normal popliteal artery flow
  
• Knee in neutral position

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Digital Subtraction Angiography

• Severe stenosis of the popliteal artery (Black
  arrow)
  
• Full extension at the knee and active plantar
  extension at the ankle
  

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Differential Diagnosis
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Histologic changes with continued entrapment
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Treatment

• The principles surrounding treatment of PAES are
  release of the arterial compression, restoration
  of as near-normal anatomy as possible, and
  preservation or restoration of arterial flow to
  the limb
• Surgery is the mandatory treatment of PAES except
  in the case of asymptomatic functional PAES
  
• If fibrosis has reached a point where there is
  aneurysm formation and thrombogenic activity in
  the artery simple release of the artery will not
  prevent worsening of the situation
• Therefore vascular reconstruction may be
  necessary
  

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Surgical Treatment

• Diagnosis and surgery at an early stage will
  decrease the need for vascular reconstruction
  
• A simple myotomy is all that is required
• This will result in fewer complications and a
  better prognosis
  
• Musculotendinous section in the absence of
  arterial damage is the procedure carried out on
  this 21 year old male
  

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Musculotendinous section in the absence of
arterial damage

• A posterior approach, via an S- or Z-shaped
  incision allows
  
• Greater flexibility for the surgeon
• Closer inspection of the structures within the
  popliteal fossa
  
• Sufficient exposure for arterial reconstruction
  if required
  
• Allows short saphanous vein to be harvested

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• The major obstruction was at the medial head of
  the gastrocnemius tendon
  
• Tendon was incised
• And removed from around the popliteal artery
• Popliteal artery was followed to the adductor
  hiatus
  
• Found to be free of obstruction

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Complications

• Symptoms, such as claudication, may occasionally
  persist or recur postoperatively.
  
• If this occurs in the early postoperative period
  then incomplete division of the aberrant
  musculotendinous portion must be considered.
  
• In this event, further operative intervention may
  be required.
  
• Other complications may occur as a result of
  operative intervention such as infection and
  hematoma formation.

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Other therapies

• Endoluminal procedures including intra-arterial
  thrombolysis, percutaneous transluminal
  thromboembolectomy, and percutaneous transluminal
  dilatation are a possibility but they will not
  prevent ongoing problems in the presence of
  fibrosis and vascular reconstruction is required
• Thrombolytic therapy to improve distal runoff is
  described as useful to its use in patients with
  thrombosed popliteal artery aneurysms. This
  appears a reasonable assertion and may reduce the
  extent of, if not the need for, reconstruction.

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Prognosis

• The most exhaustive follow-up study was performed
  by di Marzo et al. They reported both a
  statistically significant lower complication rate
  for MTS as well as a higher patency rate with MTS
  (95) over reconstruction (65).
• Also, patients undergoing MTS were better able to
  undertake a standardized treadmill test than
  those following reconstruction (96 vs. 67).
  
• These results may be explained, in part, by the
  significantly worse runoff status (P and increased likelihood of presence of
  thrombosis, aneurysm, or both (P patients who subsequently underwent
  reconstruction.

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Outcome

• Patient was discharged following surgery
• Returned to work within three weeks of surgery
• Completely asymptomatic following wound healing
• At last follow-up could stand for prolonged
  periods without calf or foot pain
  

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References

• Principles and Practice of Surgery 4th ed by J.
  Garden, A.W. Bradbury, J. Forsythe
  
• Essentials of General Surgery 3rd ed by
  P.Lawrence
  
• Ind J Radiol Imag 2002 12191-93
• J Vasc Br 20032(3)210-8
• Di Marzo L, et al. Popliteal artery entrapment
  syndrome the role of early diagnosis and
  treatment. Surgery 1997, 12226-31
  
• Popliteal Artery Entrapment Syndrome Mark F.
  Henry, MRCS, Denis C. Wilkins, MS, FRCS, and
  Anthony W. Lambert, MS, FRCS (Gen Surg) Current
  Treatment Options in Cardiovascular Medicine
  2004, 6113-120

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