Contrast enhancing epidural fluid accumulation after percutaneous endoscopic lumbar discectomy: A case report of recurrent disc herniation within pseudocyst secondary to irrigation fluid

Introduction: Percutaneous endoscopic lumbar discectomy (PELD) is increasingly being utilized to treat patients with lumbar disc herniation. PELD is unique in that it uses a single working port endoscope with constant irrigation of the surgical field to visualize pathology. The current report is of a case of postoperative epidural irrigation fluid accumulation presenting as peripherally enhancing epidural lesions, masking an underlying reherniation. Presentation of case: A patient with a Lumbar 5-Sacral 1 level disc herniation presenting with radiculopathy was treated using PELD. Following the operation, the patient experienced recurrent pain, prompting a repeat MRI of the lumbar spine. Multiple ring-enhancing lesions within the epidural space were observed, creating diagnostic dilemmas. The differential diagnoses included epidural abscess, pseudomeningocele from unintended durotomy, epidural hematoma, or trapped epidural fluid collection presenting as a pseudocyst with or without recurrent disc herniation. A repeat endoscopic discectomy was performed to confirm the diagnosis of pseudocyst, revealing a recurrent disc herniation. Discussion: Pseudocysts are not an uncommon complication of PELD, typically believed to be due to an inflammatory response to disc fragments. However, in this case, the epidural fluid collection was likely the result of trapped irrigation fluid from continuous irrigation during the procedure, which masked an underlying reherniation on imaging. Conclusion: With the increasing utilization of PELD, it is important to acknowledge unique complications such as fluid accumulation from irrigation within the epidural space. Fluid accumulation can lead to contrast-enhancing pseudocyst formation, which can theoretically lead to mass effect or increased intracranial and intraspinal pressure and may mask additional underlying pathology.