Classic history and presentation: Individuals with PS often have a history of prolonged sitting, such as desk work, driving, cycling, or horseback riding, or a fall onto the buttocks. Clinical presentation may include low back and unilateral buttock pain, along with burning or numbness migrating down the back of the leg. The pain is typically increased with hip flexion and internal rotation.
Prevalence: Reports of incidence vary widely, ranging from 5%-36%. It is likely that PS is underdiagnosed, and cases are treated under the name of a different condition.
- Age – Most patients are between the ages of 30 and 50 years.
- Sex / gender – Reports are inconsistent; it is unclear if sex plays a significant role in PS.
Pathophysiology: PS is caused by piriformis muscle contractures / spasms from overuse / underuse, trauma, or hypertrophy. However, several structures could contribute to nondiscogenic entrapment of the sciatic nerve in the subgluteal space: local scar tissue or fibrous bands, other posterior hip muscles, vascular abnormalities or aberrant anatomy, and space-occupying lesions such as a tumor or hematoma.