Transdural cauda equina herniation after uneventful lumbar surgery: A case report and review of the literature

Background: Although incidental dural tears are relatively common during spine surgery, transdural nerve root herniation without the identification of dural tear is a rare complication during spine surgery.Case presentationAn 80-year-old woman was diagnosed with L4-5 degenerative spondylolisthesis with spinal stenosis. The patient underwent L4-5 posterior decompression surgery and without any obvious incidental dural tear during surgery. On postoperative day (POD) 2, she complained of left leg pain. Magnetic resonance imaging (MRI) on POD 3 did not show any clearly causative lesion. Her left leg pain remained, but she was ambulatory. MRI findings on POD 15 were suggestive of transdural nerve root herniation contained in a pseudomeningocele. Reoperation was performed on the same day. Herniated cauda equina fibers were observed through a dural tear and dural closure was performed with continuous suturing after reduction of the herniated cauda equina fibers. Her left leg pain resolved immediately after surgery. At 12 months after surgery she reported that she had been doing housework without pain or bladder problems. Conclusion: Reoperation was performed for transdural nerve root herniation after lumbar decompression surgery, and resulted in a favorable outcome. Clinicians should be aware that transdural nerve root herniation can occur, even if no dural tear is identified intraoperatively.