Case of the Month #27: Lower back and buttock pain by Dr Kerry Bosworth

Piriformis syndrome

Piriformis syndrome (PS) has been suggested to account for up to 6% of all lower back pain and is caused by compression of the sciatic nerve by the piriformis muscle. Trauma to the buttocks can lead to soft tissue inflammation and muscle spasm. Overuse injuries may also be seen. PS typically gives lower back and buttock pain which radiates along the posterior thigh in the distribution of the sciatic nerve. Pain is exacerbated by standing from a sitting position and by sitting for an extended period of time. It is most common in middle-aged female patients. There are a number of clinical tests used on examination including the Beatty’s test, Pace test, Freiberg test, FAIR test and Lasague’s sign. These are explained in the recommended reading.

Diagnosis of PS is complicated by the wide range of conditions that may present in a similar manner including lumbosacral disc pathology, spinal stenosis, spondylolisthesis, sacroiliac joint pathology, hamstring injury, proximal hamstring syndrome, ischio-femoral impingement syndrome, gemelli-obturator internus syndrome, malignancy and arteriovenous malformations. Imaging may be helpful and ultrasound has been shown to be a useful aid in diagnosis.

Rest followed by mobilisation is advised. Piriformis stretching can also be of benefit. NSAIDs are the first line analgesics but gabapentin and pregabalin have also been used. Mannitol and vitamin B treatment has shown improvement. 

Ultrasound guided injections of local anaesthetic and steroid may provide relief for those not responding to other treatments. Botox may also been used. Rarely, surgical intervention can be considered.

Difficult consultations

Assessment of patients in the pain clinic can often be very challenging and unrealistic expectations are frequently encountered, like the “magic” solution that this patient wanted to find. Pain catastrophizing alters the structure of the brain and pain processing in the brain and spinal cord is amplified. Patients with high PCS scores can let their feelings of helplessness about pain impede their engagement with therapies, as is seen in this case. It can also undermine the response to treatment.

Motivational interviewing may be used to empower the patient to use their own motivational factors to take positive steps in their pain management. Life events, such as the arrival of a grandchild, can lead patients into the contemplation stage of The Stages of Change Model and to take action. This can allow them to address their cognitive dissonance: in this case, her resistance to treatment options while also wanting to find a way to be the grandmother that she wants to be.

More information about enhancing the therapeutic value of your consultations can be found in the FPM Learning Communication Skills section.

• The patient felt that the piriformis injection was the most beneficial part of her pain management. Which aspects do you feel may have benefitted her most?