Piriformis Injection

Excerpt

Piriformis syndrome is an infrequent cause of entrapment neuropathy. A diagnosis of exclusion, piriformis syndrome occurs secondary compression or entrapment of the sciatic nerve by the piriformis muscle.

Historically, the exact definition of this syndrome has varied in the literature. In 1928, Yeoman was the first to describe pain in the sciatic nerve distribution secondary to piriformis syndrome. In 1947, Robinson coined the term piriformis syndrome and proposed six cardinal features which include:

1. History of trauma to the sacroiliac and gluteal region

2. Pain in the sacroiliac joint

3. Greater sciatic notch and piriformis muscle extending down the leg and causing difficulty walking

4. Acute exacerbations brought on by stooping or lifting and relieved by traction on the affected leg

5. The presence of a palpable tender sausage-shaped mass over the piriformis muscle

6. Positive Lasegue sign and gluteal atrophy.

Since this historical report, many of Robinson's proposed diagnostic criteria have since been disputed or refuted. Contemporary dogma is accepting of a much broader clinical definition accompanying a diagnosis of piriformis syndrome, defined as a syndrome consisting of isolated sciatic pain usually limited to the buttock with radiation down the thigh .