Fig. 4. Entrapment neuropathy of the sciatic nerve caused by perineural cyst. (A) Magnetic resonance imaging of perineural cyst. (B) Two portals are utilized; the posterolateral portal and the distal accessary portal (arrows). (C) Intraoperative arthroscopic images; the perineural cyst (asterisk). (D) Decompression with cystostomy of the perineural cyst.
