Pseudomeningocele presenting with cauda equina syndrome: is a 'ball-valve' theory the answer?

Pseudomeningocele is an uncommon complication of spinal surgery. The condition is most often asymptomatic and self-limiting. A proportion of patients may present with lower back pain, dural fistulas, radiculopathy or myelopathy. Cauda equina syndrome due to a pseudomeningocele has been reported due to herniation of the Cauda equina roots through the dural defect. We report a case of large pseudomeningocele causing an impending Cauda equina syndrome by acting as an extradural mass lesion.