Table 5.

Types of corroborating data with examples

Corroborating item	Examples: description and study (first author and year)
Nerve conduction studies or electromyography show extraspinal delay	EMG findings suggestive of involvement of the inferior gluteal and peroneal branches of the sciatic nerve; case 3. Hughes et al. 1992 [49]
	Delayed responses when hip was held in FAIR position; two out of two cases. Nakamura 2003 [77]
Imaging shows structural abnormality:	Hypertrophy of PM; two cases out of two. Chen and Wan 1992 [21]
	Hypertrophy of PM. Jankiewicz et al. 1991 [53]
	T2 hypersignal at the level of PM and sciatic nerve. Jroundi et al. 2003 [55]
	Abnormal MRI neurography, suggesting entrapment at the level of the PM; 12 out of 14 cases. Lewis et al. 2006 [68]
Operative findings of abnormalities of PM and/or of sciatic nerve and/or of sciatic nerve impingement	Calcified PM. Beauchesne and Schutzer 1997 [5]
	Sciatic nerve impinged between PM and short external rotators; case number 1 out of 2. Chen and Wan 1992 [21]
	Tendinous band of PM indenting peroneal branch of the sciatic nerve; case number 3 out of 5. Hughes et al. 1992 [49]
	Impingement of the sciatic nerve by the PM; six out of seven cases. Foster 2002 [41]
	Impingement by the PM or by an associated fibrous band; all four cases that had surgery. Lewis et al. 2006 [68]
	Anomalous division of the sciatic nerve with its superior branch passing through the PM; case number 2 out of 4. Kouvalchouk 1996 [64]
	Bifurcated sciatic nerve with posterior cutaneous femoral nerve squeezed between the PM and the greater sciatic notch. Ozaki and Muro 1999 [78]
Relief following surgery (long term follow up not reported)	Pain increasing for 9 weeks after fall, relief following excision of calcified muscle. Beauchesne and Schutzer 1997 [5]
	Seven cases, average duration of pain of 2 years, immediate improvement after division of PM and return to work, and relieved of symptoms at 3–6 months. Foster 2002 [41]
	Three cases out of four had surgery. Lewis et al. 2006 [68]
Prolonged post-operative relief (over one year)	Both cases out of two. Chen and Wan 1992 [21]
	All four cases. Kouvalchouk et al. 1996 [64]
	Case 1. Nakamura 2003 [77]
Relief following X-ray guided injection of local anaesthetic and corticosteroid into PM (long term follow up not reported)	Pain for 7 months, free of pain at the 3-month follow-up after two injections. Bustamente [12]