Does endoscopic piriformis tenotomy provide safe and complete tendon release? A cadaver study

Abstract Background Endoscopic piriformis release (EPR) is among the available treatments for piriformis syndrome. This procedure typically involves dividing the muscle near the sciatic nerve in the sub-gluteal space, which contains numerous blood vessels and nerves. The objectives of this prospective cadaver study were: 1) to assess the reproducibility and quality of endoscopic piriformis tenotomy near the greater trochanter; 2) to detect iatrogenic injuries to the lateral hip rotators, nerves, and vessels; 3) and to define the surgical safety margins relative to the sciatic nerve and inferior gluteal bundle. Hypothesis EPR at the greater trochanter ensures full release of the muscle with a limited risk of neuro-vascular injury. Material and methods EPR was performed via two portals on 10 cadaver hips preserved in zinc chloride and placed in the prone position. A third, ancillary portal was required in 7 cases. The area was then dissected with the Kocher-Langenbeck approach to allow an assessment of the tenotomy, detect iatrogenic injuries, and measure the distances separating the tenotomy site from the sciatic nerve and inferior gluteal artery. Results Complete tenotomy was achieved in 9 (90%) cases. The tendon adhered to the capsule in 2 (20%) cases and showed acquired avulsion in 1 case. No injuries to the sciatic nerve or inferior gluteal artery occurred. Mean distances from the tenotomy site were 5.21 ± 0.59 cm (range, 4.5–6.6 cm) for the sciatic nerve and 7.1 ± 0.89 cm (range, 5.4–8.5 cm) for the inferior gluteal artery. Discussion EPR by a tenotomy at the greater trochanter without sciatic nerve release provides full release of the muscle with satisfactory safety margins and a short learning curve. Level of evidence III, prospective cadaver case-control study.