A human donor (cadaveric) observation study of three needle placements in the piriformis muscle

ABSTRACT

Objective

To compare the safety and accuracy of three dry needling locations in the piriformis muscle using human donors.

Design

Observational dissection study of embalmed human donors.

Methods

A licensed physical therapist of 17 years clinical experience and 5 years teaching dry needling placed three needles in a medial, midpoint, and lateral location of 14 piriformis muscles of seven embalmed human donors. Block dissection allowed for observation of tissues the needles traversed and recording of the structures that the needles pierced.

Results

The lateral needle pierced piriformis in 3/14 trials, and contacted sciatic nerve in 0/14 trials. The medial needle pierced both piriformis and sciatic nerve in 11/14 trials. The midpoint needle pierced the piriformis in 11/14 trials, and contacted sciatic nerve in 3/14 trials. Fisher’s Exact test (p < 0.001) found a nonrandom association between dry needle placement, and dry needle contact.

Conclusions

When dry needling the piriformis, a lateral approach can avoid the sciatic nerve, but cannot accurately pierce the piriformis tendon. Furthermore, while a midpoint and medial approach finds the piriformis muscle with the same accuracy, the midpoint location avoided the sciatic nerve more often.

KEYWORDS:

• Piriformis muscle
• piriformis syndrome
• myofascial pain
• dry needling
• human donor
• cadaver

Acknowledgments

The authors express gratitude to Dean Kolk and Mark Weaver for statistical consultation, to Shani Lewis for graphics, to Monica Zimmerman for proofreading, and to the Elon Anatomical Gift Program.

Disclosure statement

The authors do not have any conflicts of interest.

Ethical approval

Elon University does not require an IRB when performing investigations using human donors (cadavers).

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.