Deep gluteal syndrome: an overlooked cause of sciatica

Mention sciatica and most clinicians will first think of pressure on the lumbosacral nerve roots from a herniated intervertebral disc or stenosis of the spinal canal. Magnetic resonance imaging (MRI) raised hopes of making more precise anatomical diagnoses, but MRI, as routinely practised, fails to demonstrate the cause in as many as 49% of patients¹ while disc lesions are present in many asymptomatic people.

A less well known cause of sciatica is impingement of the nerve trunk from a range of musculoskeletal conditions that compress the sciatic nerve as it passes through the confines of the deep gluteal space, termed the deep gluteal syndrome (DGS). This editorial seeks to answer four questions. First, what is the evidence that deep gluteal syndrome exists? Second, how common is it? Third, are there accurate diagnostic tests? Fourth, are there effective treatments? MEDLINE, EMBASE, CINAHL and PEDro were searched using the term ‘deep gluteal syndrome’ without filters. Systematic reviews and primary research were assessed for bias and the best available evidence is reported. Non-systematic reviews were read for background and secondary references.

Compression of the nerve by the piriformis muscle was the first of such conditions to be described and led to the term ‘piriformis syndrome’.² This term is being replaced by DGS as other musculoskeletal structures have been shown to cause sciatica, and in acknowledgement that we often do not understand the precise pathophysiology of a patient’s symptoms and signs. It is estimated that between 6%³ and 17%⁴ of patients seen in secondary care with sciatica meet the diagnostic criteria for DGS, though difficulties with case definition may have led these two studies, which are the best of the prevalence studies, to underestimate the …