A Rare Case of a Discal Cyst Following Percutaneous Endoscopic Lumbar Discectomy via a Transforaminal Approach.

A discal cyst is a rare lesion that causes low back pain and radiculopathy of the lower extremities. There are several reports of discal cysts occurring after surgery, but data are limited on their occurrence after percutaneous endoscopic discectomy (PED). A 21-year-old man with disc herniation at the L4-L5 disc level underwent PED via a transforaminal approach. The immediate postoperative course was uneventful and his symptoms were relieved. Six weeks after surgery, low back pain and mild pain in the left thigh recurred. Magnetic resonance imaging (MRI) revealed a cystic lesion adjacent to the left side of the L4-L5 intervertebral disc. Conservative treatment was ineffective, so we reoperated using PED with the same approach. Pain improved and MRI revealed disappearance of the cystic lesion. When symptoms relapse after PED, it is necessary to consider the occurrence of a cyst.