Background:
Pseudomeningocele, an extradural collection of cerebrospinal fluid (CSF), has only been rarely reported to occur spontaneously in conjunction with isthmic spondylolisthesis (with lysis) in the lumbar spine.
Case description:
A 68-year-old male presented with low back pain and neurogenic claudication of several years duration without any history of trauma, epidural spine injections, or spine surgery. Lumbosacral magnetic resonance imaging (MRI) revealed a grade-I L4-L5 isthmic spondylolisthesis with spinal canal narrowing and a posterior paravertebral collection consistent with CSF. The patient underwent a spinal decompression consisting of a complete L4 and partial L5 laminectomy, a bilateral L4-L5 instrumented fusion (due to the lysis defect), and closure of the CFS fistula. The histology analysis was compatible with a pseudomeningocele.
Conclusion:
Lumbar isthmic spondylolisthesis may lead to changes in the elastic properties of the underlying dura mater. Rarely, this may lead to meningeal tears and formation of a pseudomeningocele. Historically, one must always check for a prior epidural injection that could have resulted in this complication. Additionally, as most likely the case here, the lysis defect was responsible for the foraminal dural laceration resulting in the pseudomeningocele.