Piriformis syndrome



Background

  • "Sciatica" entrapment not originating from nerve root compression
  • Probable compression of sciatic nerve, by piriformis muscle
  • Piriformis normally helps ext rotate hip
  • Inactive gluteals vs tight hip flexors (so piriformis strains at hip extension & rotation → compressing the sciatic N.)

Clinical

  • Clinical diagnosis
  • Unilateral (rarely bilat.) buttock pain radiating to hamstrings or below
  • F:M = 3:1
  • 30 - 40 yo
  • Exacerbated by sitting or prolonged "flexion" exercise (e.g. cycling)
  • Associated pudendal nerve compression may result in transient saddle paraesthesia or sphincter symptoms
  • Symptoms relieved by hip extension or ext. rotation (patients walk "toe out")
  • No red flags
  • No convincing root irritation (e.g. valsalva) symptoms
  • Nil constitutional
  • SLR near normal
  • No motor, sphincter or perianal pinprick sensation abnormalities
  • Trigger point at sciatic notch (½ way between ischium & Gr. trochanter)
  • FAIR (hip flexion/adduction/int. rotation) manoeuvre triggers symptoms

Differential Dx


Investigations

  • EMG studies in difficult cases (GP to arrange)

Management

  • Muscle stretching & gluteal strengthening exercises and education (physio referral)
  • NSAIDs
  • Ice


Content by Dr Íomhar O' Sullivan 25/02/2009. Last review Dr ÍOS, Dr C Luke 18/06/21.