Physiotherapists and other manual therapists recognise piriformis syndrome as a cause of buttock and leg pain which sometimes simulates sciatic symptoms. The piriformis muscle is very close to the sciatic nerve as it traverses the buttock and nerve compression or irritation have been put forward as reasons for the pain. Piriformis syndrome is not recognised universally outside physiotherapy and other therapy professions but the diagnosis is gaining credence.
The piriformis muscle is flat and small, lying in the centre of the buttock, taking its origin from the sacral area and inserting on to the top of the greater trochanter of the thigh, the bony prominence easily felt on the side of the leg below the hip. It either turns the leg outwards or moves the thigh away from the body, depending on the position of the hip. The sciatic nerve and the piriformis muscle vary in their structure and position in the buttock. Typically the muscle lies behind the nerve but in some cases the piriformis is divided into two parts with the sciatic nerve passing between them.
There are no clear causative factors for piriformis syndrome which seems to accompany other lumbar or pelvic pains. Direct trauma to the area can cause bleeding and scarring around the nerve and the muscles, with consistent pressure to the buttock perhaps affecting the nerve’s function. The syndrome can also be associated with an increased lordotic posture, hip replacement or vigorous activity and mimics back pain syndromes such as sciatica. Physiotherapists diagnose and treat piriformis syndrome on purely clinical grounds as there are no agreed diagnostic criteria, imaging or other tests.
Piriformis syndrome is often not considered as a cause of low back and leg pain but can mimic sciatic nerve compression, giving symptoms similar to back pain with L5 or S1 nerve compression from disc or joint changes. Cases of trochanteric bursitis may be connected to this syndrome as the muscle inserts onto the trochanter. Physio clinical examination will find intense pain over the piriformis trigger point in the buttock, reduced lateral rotation of the hip, pain and weakness on resisted hip abduction and lateral rotation and a difficulty sitting on the affected buttock.
Physiotherapists use many treatment modalities to improve piriformis symptoms but partly due to the lack of a clear diagnosis there is no agreed scientific treatment approach. Physios check the findings such as tightness in the piriformis, hip external rotator and adductor muscles, hip abductor weakness, sacro-iliac and lumbar dysfunction, externally rotated hip in walking, apparent leg shortening and a shorter stride length.
If the physiotherapist finds that the piriformis and other muscles are tight then treatment consists of loosening up the hip joint followed by stretches of the muscle. Stretching the muscle is performed in lying with the hip flexed, pulling the hip into adduction and internal rotation. A home stretching programme is important, with regular stretching every two or three hours in the acute phase. If the piriformis is looser than expected the Physio may exercise the muscle to tighten it up and stretch out the tight structures which oppose this tendency.
Local manipulation is a common treatment directly over the most painful point in the buttock, which can be very tender indeed. Transverse or longitudinal mobilisations over the muscle is the technique used, maintaining the pressure steadily for up to 10 minutes initially. Treatment of the back and sacro-iliac joints is important to address any dysfunction which might contribute. Modifying posture and activity, muscle injections, mobilisations and stretching are commonly successful in reducing symptoms. In resistant cases surgery to the muscle or the tendon at the greater trochanter may be contemplated.