case_images: PMC6743682_01
case_images: Preoperative magnetic resonance imaging showing location of epidural (a,b) and foraminal (c) cysts which are hyperintense on T2 weighted images.
case_images: SNI-10-58-g001.jpg
case_images: PMC6743682_01_SNI-10-58-g001.jpg
case_images: F1
case_images: The magnetic resonance (MR) imaging showed severe L4-L5 stenosis, and two lumbar cysts: cyst I was located in the left foramen, while Cyst II was situated between the dura and ligamentum flavum; there was no evidence of instability [Figures 1 and 2].
case_images: Preoperative X-ray lateral neutral (a), flexion (b), and extension (c) views without any evidence of instability.
case_images: SNI-10-58-g002.jpg
case_images: PMC6743682_01_SNI-10-58-g002.jpg
case_images: F2
case_images: The magnetic resonance (MR) imaging showed severe L4-L5 stenosis, and two lumbar cysts: cyst I was located in the left foramen, while Cyst II was situated between the dura and ligamentum flavum; there was no evidence of instability [Figures 1 and 2].
case_images: Intraoperative images showing huge foraminal cyst I (In circle).
case_images: SNI-10-58-g003.jpg
case_images: PMC6743682_01_SNI-10-58-g003.jpg
case_images: F3
case_images: A transforaminal endoscopic approach revealed that cyst I was attached to the left facet joint; indeed, it proved to be a synovial cyst [Figure 3].
case_images: Intraoperative images showing: (a) Huge intraspinal epidural cyst II (In circle) not attached to ligamentum flavum or dura. (b) Sever adhesion between the ligamentum flavum and dura mater. (c) Free dura after cyst removal.
case_images: SNI-10-58-g004.jpg
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case_images: F4
case_images: A full endoscopic interlaminar approach was utilized to excise cyst II; this huge epidural cyst with marked adhesions was not connected to either the ligamentum flavum or the dura [Figure 4]. [Video 1].
case_images: Magnetic resonance imaging on 1st postoperative day revealed no residual pathology and adequate decompression on T2-weighted sagittal (a) and axial (b,c) images at the L4-L5 level.
case_images: SNI-10-58-g005.jpg
case_images: PMC6743682_01_SNI-10-58-g005.jpg
case_images: F5
case_images: Postoperatively, the patient had immediate pain relief and remained asymptomatic 6 months later [Figure 5].
case_images: Microscopic sections (a-40x, b-100x, c-400x) showing granulation tissue with microcalcifications, woven bone formation, hemosiderin pigments, and focal cystic changes. The lining epithelium of cystic component is denuded.
case_images: SNI-10-58-g006.jpg
case_images: PMC6743682_01_SNI-10-58-g006.jpg
case_images: F6
case_images: The "Spontaneous Degenerative Epidural Cyst II," located in the epidural space between the dura and the ligamentum flavum, showed granulation tissue with microcalcifications, woven bone formation, hemosiderin pigmentation, and focal cystic changes [Figure 6].