Spinal hematoma compressing cauda equina.

Epidural and subdural spinal hematomas are unusual complications of diagnostic lumbar punctures. A renal allograft recipient on anticoagulant therapy underwent lumbar puncture. Urinary retention and evidence of an S2, S3, and S4 neurologic deficit developed subsequently. A myelogram showed a defect of the posterior lumbosacral spinal canal. Urodynamic investigation demonstrated normal sympathetic innervation of the proximal urethra and impaired parasympathetic and pudendal innervation of the detrusor and external urethral sphincter, respectively.