Performed by – Sarmad Kazzaz, Mark Thomas, Adam Way

The piriformis muscle extends anatomically from the inner surface of the sacral bone and is inserted into the long bone of the leg, the femur. Occasionally the piriformis muscle may become irritable and goes into spasm and may be the cause of sciatic type pain in about 10% of cases of sciatica.

Features of the clinical presentation include buttock pain, referred pain to the thigh or frank sciatic pain, pain on sitting on the affected butt ock and difficulty climbing stairs or inclines.

There are no radiological investigations such as x-rays or scans which adequately demonstrate the presence or absence of a piriformis type syndrome and therefore the diagnosis is made predominantly on clinical grounds. Piriformis syndrome however may be a secondary feature of other spinal abnormalities such as wear and tear in the facet joints or a prolapsed intervertebral disc and therefore your clinician will probably organise an MRI scan of the lumbar spine to establish whether there are other primary changes responsible for the symptoms related to the piriformis muscle.

Treatment of piriformis syndrome consists initially of physiotherapy focusing on stretching the piriformis muscle. If radiological investigations such as scans demonstrate an abnormality in the lumbar spine these will have to be addressed as failure to address the primary pain generator will not adequately solve a piriformis problem.

If physiotherapy fails to alleviate the intense muscle spasm and associated referred pain, then targeted injection of the piriformis muscle is possible under x-ray or CT guidance and sedation. Initially injections into the piriformis muscle consist of preparations of local anaesthetic and a steroid however botulinum toxin has been very successfully injected into the muscle to alleviate spasm and there is reasonably good evidence based for the employment of this technique.