The clinical features of the piriformis syndrome: a systematic review

Piriformis syndrome, sciatica caused by compression of the sciatic nerve by the piriformis muscle, has been described for over 70 years; yet, it remains controversial. The literature consists mainly of case series and narrative reviews. The objectives of the study were: first, to make the best use of existing evidence to estimate the frequencies of clinical features in patients reported to have PS; second, to identify future research questions. A systematic review was conducted of any study type that reported extractable data relevant to diagnosis. The search included all studies up to 1 March 2008 in four databases: AMED, CINAHL, Embase and Medline. Screening, data extraction and analysis were all performed independently by two reviewers. A total of 55 studies were included: 51 individual and 3 aggregated data studies, and 1 combined study. The most common features found were: buttock pain, external tenderness over the greater sciatic notch, aggravation of the pain through sitting and augmentation of the pain with manoeuvres that increase piriformis muscle tension. Future research could start with comparing the frequencies of these features in sciatica patients with and without disc herniation or spinal stenosis

Brief review: Piriformis syndrome: Etiology, diagnosis, and management

Purpose: In this narrative review, we aim to provide the pathophysiology and diagnostic criteria of the piriformis syndrome (PS), an underdiagnosed cause of buttock and leg pain that can be difficult to treat. Based on existing evidence, frequencies of clinical features are estimated in patients reported to have PS. In view of the increasing popularity of ultrasound for intervention, the ultrasound-guided technique in the treatment of PS is described in detail. Source: A literature search of the MEDLINE® database was performed from January 1980 to December 2012 using the search terms e.g., " piriformis injection", " ultrasound guided piriformis injection", " botulinum toxin", "pain management", and different structures relevant in this review. There was no restriction on language. Principal findings: A review of the medical literature pertaining to PS revealed that the existence of this entity remains controversial. There is no definitive proof of its existence despite reported series with large numbers of patients. Conclusion: Piriformis syndrome continues to be a controversial diagnosis for sciatic pain. Electrophysiological testing and nerve blocks play important roles when the diagnosis is uncertain. Injection of local anesthetics, steroids, and botulinum toxin into the piriformis muscle can serve both diagnostic and therapeutic purposes. An ultrasound-guided injection technique offers improved accuracy in locating the piriformis muscle. Optimizing the therapeutic approach requires an interdisciplinary evaluation of treatment