Piriformis syndrome

• piriformis syndrome
  • a tight piriformis muscle may compress the sciatic nerve
    • nerve impingement may result from overuse or hypertrophy of the piriformis muscle
    • nerve impingement may cause features such as radicular pain, numbness, or weakness of the lower extremity
  • clinical examination
    • reveals point tenderness over the buttocks medial to the greater trochanter
    • pain may be exacerbated by internal rotation of the hip may exacerbate the pain
  • differential diagnosis includes
    • trochanteric bursitis
    • sacroiliac joint pain
  • treatment
    • rest, ice, and stretching of the muscle (toe touching with the legs crossed)
    • if non-invasive measures fail, local anaesthetic and corticosteroid injections can be tried
    • failure of conservative measures may require open or arthroscopic surgical release of the piriformis muscle/tendon
    • sciatic neurolysis has been used in this condition

Notes:

• piriformis muscle
  • originates from the pelvic surface of the sacrum, exits through the greater sciatic notch and inserts onto the apex of the greater trochanter of the femur. It functions as an external rotator of the hip when the hip is extended and as a hip abductor when the hip is flexed at 90 degrees
  • in the majority of cases the sciatic nerve runs distal to the piriformis muscle. However, there are variations involving a split or single sciatic nerve passing proximal, through or distal to a split or single piriformis muscle

Reference:

• (1) Noesberger B, Eichenberger AR. Overuse injuries of the hip and snapping hip syndrome. Operative Techniques in Sports Medicine 1997; 5 (3):138-142.
• (2) Kobbe P, Zelle BA, Gruen GS. Case report: recurrent piriformis syndrome after surgical release. Clin Orthop Relat Res 2008; 466: 1745-8.