The Paraneural Sciatic Sheaths in Longitudinal Axis at the Level of Greater Trochanter: An Ultrasound Cadaveric and Clinical Correlation Study.

Abstract

Paraneural sheath engulfing the sciatic nerve (SN) between the ischial tuberosity and the greater trochanter is well known. In order to explore the anatomical planes separating the paraneurium from the epineurium in SN, we conducted a cadaveric study (two patients and four specimens), followed by a clinical study in 10 patients. We demonstrated an elevation of 5-7 layers of paraneural tissues after an in-plane injection in the longitudinal axis of the proximal SN, which was possibly the last of the paraneural sheath. In the clinical study, the block provided low pain scores with no rescue analgesia postoperatively and no neurological deficit at the time of discharge. This is probably the first series which has described the elevation of several layers of paraneural tissues after an in-plane injection in the longitudinal axis of the proximal SN.