Pseudomeningocele Presenting with Neurological Symptoms 1 Year after Spinal Surgery: A Case Report

Introduction: Pseudomeningocele is a recognized post-operative complication of spinal surgery; however, most patients remain asymptomatic, and neurological manifestations are rare. Consequently, reports providing detailed intraoperative findings are limited. Here, we report a rare case of post-operative pseudomeningocele presenting with neurological symptoms >1 year after the initial surgery. Case Report: A 53-year-old male with thoracolumbar ossification of the ligamentum flavum (OLF) at the T1/2 and L2/3/4 levels underwent T1 laminectomy and L2-4 laminoplasty. Intraoperatively, a dural tear occurred at the lumbar level and was primarily repaired. One year later, the patient developed acute lower back pain, left lower limb pain, and progressive weakness while performing household cleaning in a forward-flexed posture. Pre-operative imaging suggested L3/4 disc herniation and residual OLF at the same level, and surgical treatment (microscopic discectomy and laminoplasty) was planned. After drilling the left facet joint for discectomy, a sac-like structure, which was continuous with the dura mater, migrated posteriorly. This structure was diagnosed as a pseudomeningocele, rather than a disc herniation. No cerebrospinal fluid leakage or dural injury was observed. Adequate decompression was performed without manipulating the pseudomeningocele. The patient's symptoms resolved postoperatively with no recurrence at the 6-month follow-up. Conclusion: This case demonstrates that a pseudomeningocele, although typically asymptomatic, can cause delayed neurological symptoms >1 year after dural repair. Clinicians should consider post-operative pseudomeningocele as a differential diagnosis in patients with new neurological deficits after spinal surgery.