Leg Pain? Are you SURE its a disc?

Gluteus minimus dysfunction is often present in gait disorders, including stance phase mechanical problems, since it fires from initial contact through pre swing, like it better known counterpart, the gluteus medius. It is interesting that the trigger point referral pattern of the gluteus minimus has a sciatic distribution, whereas the gluteus medius is more in the local area of the hip. 

 There are several, well known effects of dry needling:

decreased central sensitization

increased range of motion

changes in muscle activation

changes in the chemical environment surrounding a trigger point

changes in local and referred pain

and now we can add (not surprisingly), changes in autonomic function. The mechanism probably has something to do with pain and the reticular formation sending information down the cord via the lateral cell column (intermediolateral cell nucleus) or pain (nociceptive) afferents sending a collateral in the spinal cord to the dysfunctional muscle (Dr Ivo talks about these mechanisms in his dry needling and acupuncture lectures). 

Conclusions

The presence of active TrPs within the gluteus minimus muscle among subacute sciatica subjects was confirmed. Every TrPs-positive sciatica patient presented DN related vasodilatation in the area of referred pain. The presence of vasodilatation suggests the involvement of sympathetic nerve activity in myofascial pain pathomechanism.

BMC Complement Altern Med. 2015; 15: 72. Published online 2015 Mar 20. doi:  10.1186/s12906-015-0587-6PMCID: PMC4426539 Intensive vasodilatation in the sciatic pain area after dry needling

link to full text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4426539/