This article is divided into several pages for easier reading:

6.0     Prevalence and Risk Factors

The prevalence of risk factors for piriformis symdrome include:

  • Epidemiological figures of the prevalence are unknown, but are estimated to be about 12.2% to 27% (Knudsen, Mei-Dan & Brick, 2016).
  • “Reported incidence rates for piriformis syndrome among patients with low back pain vary widely, from 5% to 36%.” (Boyajian-O’Neill et al., 2008, p.657).
  • “Other studies report varying incidence of PS (8% to “rare”) in patients presenting with low back/buttock pain.” (Miller, White & Ross, 2012, p.577).
  • “…occurs most frequently during the fourth and fifth decades of life and affects individuals of all occupations and activity levels.” (Boyajian et al., 2008, p.657).
  • Being middle-aged (mean age 38) (Jankovic, Peng & van Zundert, 2013).
  • It is more common in women than men, possibly because of biomechanics associated with the wide quadriceps femoris muscle angle (i.e. ‘Q angle’) in the os coxae (pelvis) of women (Pace & Nagle, 1976).
  • Being female (Jankovic, Peng & van Zundert, 2013).
  • Overuse or vigorous activity.
  • Improper use or prolonged disuse of the pelvis.
  • Prolonged sitting, walking or running, and may feel better after lying down on the back (supine).
  • Blunt trauma in the gluteal region. It is believed to result from a haematoma following trauma, the commonest mechanism being compression or scarring of the sciatic nerve following a simple fall onto the buttocks.
  • Asymmetry/anatomical variation of the piriformis muscle(s).
  • Disease, for example a tumour.

6.1     Inaccuracy across Studies

  • “Many of these studies are hampered by a retrospective design and are weakened by a lack of uniform inclusion criteria.” (Miller, White & Ross, 2012, p.577).
  • “Review of this subject is hampered by a lack of standardized and accepted diagnostic criteria, making objective, rigorous comparison of different syndromes impossible.” (Miller, White & Ross, 2012, p.587).
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